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Articles by X Zhang
Total Records ( 47 ) for X Zhang
  X Liu , X Zhang and I. Lee
 

Fluid shear stress (FSS) is widely explored regarding its influence on osteoblasts. In vitro studies have shown that the cytoskeleton is very important in cellular responses to FSS. However, morphological changes, which would reflect the cytoskeleton changes as well as other cellular responses, were rarely quantitatively studied in the past years. Therefore, FSS-induced morphological changes in osteoblasts were quantified in this study. Real-time rapid morphological responses were observed by exposing osteoblasts to FSS with magnitude of 1.2, 1.6, and 1.9 Pa for 1 h. Afterward, osteoblast actin cytoskeleton was labeled with rhodamine phalloidin and observed using fluorescence microscopy. The results showed that 1.6 and 1.9 Pa FFS resulted in significant cellular elongation and reorientation along the direction of fluid flow. Besides, along with the enhancement of FSS magnitude, cytoskeleton aggregated more remarkably. Furthermore, extracellular Ca2+-depleted fluid flow was also used to stimulate osteoblasts for 1 h with magnitude of 1.6 and 1.9 Pa. No morphological change was observed after removing extracellular calcium. Our study suggested that the level of FSS from 1.2 to 1.9 Pa is capable of influencing cellular morphology, and extracellular calcium might play a role in osteoblasts' response to FSS stimulation.

  X Ren , J Zhang , X Gong , X Niu , X Zhang , P Chen and X. Zhang
 

The kidney is formed from two tissue populations derived from the intermediate mesoderm, the ureteric bud, and the metanephric mesenchyme. Metanephric mesenchyme is a pluripotent renal stem population, and conversion of renal mesenchyme into epithelia depends on the ureteric bud in vivo and in vitro. Embryonic stem (ES) cells have been induced to differentiate into a broad spectrum of specialized cell types in vitro, including hematopoietic, pancreatic, and neuronal cells. Such ES-derived cells can provide a valuable source of progenitor cells. However, whether ES cells can be stimulated by factors secreted from the fetal renal cells to differentiate into renal precursor cells in vitro has not been reported. In this study, we showed that murine ES cells can give rise to embryoid bodies in the absence of leukemia inhibitory factor. Culture conditions were optimized [6 days, 10 ng/ml activin and 10–7 M retinoic acid (RA)] to generate maximal mesoderm populations specifically expressing Pax2 and brachyury. Results showed that 72% of the cells were brachyury positive by fluorescent activated cell sorter on Day 6 of EB cell differentiation. Conditioned medium collected from cultures of ureteric bud cells from renal cells of a 13-day-old fetus was added to the culture medium. Mesoderm cells were cultured for up to 10 days before showing expression of renal markers, initiation of nephrogenesis (WT-1 and Pax2), and terminally differentiated renal cell types (POD-1 and E-cadherin). This study suggests that ES cells pre-treated by RA and activin can interact with secreted molecules of the fetal renal cells to specifically differentiate into renal precursor cells. Our results provide an experimental basis for the development of in vitro assays to steer differentiation of ES cells toward renal lineages.

  X Zhang , H Huang , Z Xu and R. Zhan
 

2-Methoxyestradiol (2-ME2) is an endogenous metabolite of 17β-estradiol (E2) with estrogen receptor-independent anti-cancer activity. The current study sought to determine the mechanism of anti-cancer activity of 2-ME2 in human acute T lymphoblastic leukemia CEM cells. Results showed that 2-ME2 markedly suppressed proliferation of CEM cells in a time- and dose-dependent manner. 2-ME2-treated CEM cells underwent typical apoptotic changes. Exposure to 2-ME2 led to G2/M phase cell-cycle arrest, which preceded apoptosis characterized by the appearance of a sub-G1 cell population. In addition, cytosolic cytochrome c release, increased procaspase-9 and -3 expressions, poly(ADP-ribose) polymerase (PARP) cleavage, and induced expression of caspase-8 were detected, suggesting that both the intrinsic apoptotic pathway and extrinsic apoptotic pathway were involved in 2-ME2-induced apoptosis. Moreover, the expression level of p21 protein was upregulated, whereas Bcl-2 and dysfunctional p53 protein were downregulated, which also contributed to 2-ME2-induced apoptosis. Our findings revealed that 2-ME2 might be a potent natural candidate for chemotherapeutic treatment of human acute T lymphoblastic leukemia when the precise effects of 2-ME2 were investigated further in other T leukemia cell lines and in primary T-cell leukemias.

  X Zhang , Z Zhang , G Chen , M Zhao , D Wang , Z Du , Y Xu and X. Yu
 

Previous studies have shown that histone deacetylase inhibitors (HDACis) can kill cancer cells. In addition, HDACis can induce mitotic catastrophe in cancer cells due to insufficient localization of chromosomal passenger complex (CPC) to the centromere. However, the mechanisms behind these phenomena remain unclear. In this study, we found that a HDACi, FK228, affected multiple epigenetic modification characteristics of the centromere, including enhanced acetylation of histone H3 lysine 9 (H3K9), decreased trimethylation of H3K9, and decreased phosphorylation of histone H3 serine 10 (H3S10) and centromere protein A (CENP-A). These epigenetic changes implied that H3K9 hyperacetylation inhibits the CPC recruitment, induces impaired centromere assembly and function, and eventually leads to aberrant mitosis. These data suggested that hypoacetylation of histone in the pericentromere is the most important landmark for recruiting CPC and leading to the mitotic catastrophe in HDACi-induced killing of cancer cells.

  R Ning , X Zhang , X Guo and Q. Li
 

Nuclear factor kappa B (NF-B) plays a prominent role in the pathogenesis of infectious diseases. Staphylococcus aureus (S. aureus), which can attach to and invade human osteoblasts, is the most common causative agent of osteomyelitis. To determine whether S. aureus can activate NF-B in human osteoblasts and explore the possible factors of activation in response to infection, we used flow cytometry, enzyme-linked immunosorbent assay, immunoblots, and electrophoretic mobility shift assays to quantify the invasion of bacteria, to measure the interleukin-6 (IL-6) of culture supernatants, and to investigate the IB degradation and NF-B activation in human osteoblasts. Moreover, we explored the possible factors responsible for the activation of NF-B by preventing S. aureus from physically touching human osteoblasts or inhibiting the invasion of S. aureus into human osteoblasts under co-culture conditions, by incubating proteinase K-treated or ultraviolet-killed S. aureus with human osteoblasts and by treating human osteoblasts with peptidoglycan (PGN) or lipoteichoic acid (LTA). We found that S. aureus induced the IB degradation and NF-B activation, which could regulate IL-6 secretion in the culture supernatants of human osteoblasts in response to infection. In addition, the maximal IB degradation and NF-B activation in human osteoblasts occurred prior to the maximal invasion of S. aureus. It was the attachment not invasion or the secreted soluble factor(s), PGN, LTA of S. aureus, that could induce the IB degradation and NF-B activation in human osteoblasts. These results indicated that S. aureus can activate NF-B in human osteoblasts and that the attachment of S. aureus is required for this activation in response to infection.

  Z. J Ou , W Wei , D. D Huang , W Luo , D Luo , Z. P Wang , X Zhang and J. S. Ou
 

l-Arginine can attenuate pulmonary hypertension (PH) by a mechanism that are not fully understood. This study investigated the molecule mechanism of l-arginine attenuating PH. Sprague Dawley rats were treated with monocrotaline (MCT) with or without l-arginine for 3 or 5 wk. Right ventricular systolic pressure (RVSP), right heart hypertrophy, survival rate, pulmonary artery wall thickness, nitric oxide (NO) concentration, and superoxide anion (O2·–) generation in the lung were measured. Expressions of endothelial nitric oxide synthase (eNOS) and heat shock protein 90 (HSP90), phosphorylation of eNOS at Ser1177, and the association of eNOS and HSP90 in the lung were determined by Western blot and immunoprecipitation experiments. MCT increased RVSP, right heart hypertrophy, mortality, pulmonary artery wall thickness, and O2·– generation and decreased eNOS and HSP90 expression and association, phosphorylation of eNOS at Ser1177, and NO production. l-Arginine decreased RVSP, right heart hypertrophy, mortality, O2·– generation, and pulmonary artery wall thickness and increased NO production. l-Arginine increased eNOS expression, phosphorylation of eNOS at Ser1177, and association of eNOS and HSP90 without significantly altering HSP90 expression. l-Arginine may act through three pathways, providing a substrate for NO generation, preserving eNOS expression/phosphorylation, and maintaining the association of eNOS and HSP90, which allows restoration of eNOS activity and coupling activity, to maintain the balance between NO and O2·– and delay the development of PH.

  M Pu , Z Gao , X Zhang , D Liao , D. K Pu , T Brennan and W. R. Davidson
 

The aim of the study was to assess the impact of mitral regurgitation (MR) on left ventricular (LV) anatomic and molecular remodeling and function and to determine whether early LV remodeling and function predict long-term outcome in experimental organic MR. A new rodent model of chronic MR was created. Twenty-eight rats had surgically induced MR, twelve rats had a sham operation, and twelve rats had no operation. LV diameters, volume, and mass and LV ejection fraction (LVEF) and LV fractional shortening (LVFS) were assessed using echocardiography in the early stage of MR (6 and 12 wk after induction of MR). LV hemodynamics was assessed invasively. Cardiac - and β-myosin heavy chains and sarco(endo)plasmic reticulum Ca2+-ATPase 2 (SERCA2) were measured to assess molecular remodeling and contractility. Cox's proportional hazard ratios (HR) were used to identify outcome predictors. Early LV dilation was demonstrated in rats with MR when LVEF and LVFS were still normal. LV remodeling was associated with an increase in LV end-diastolic pressure and decrease in maximal change in pressure over time. Shifting of - to β-myosin and reduced SERCA2 were observed in rats with MR. Cox's proportional hazard analysis showed that LV end-diastolic diameters (HR, 1.2–2.4; P = 0.007) and LV end-diastolic volume (HR, 1.1–1.4; P = 0.005) at 6 wk and LV mass index (HR, 1.1–2.0; P = 0.004) at 12 wk after induction of MR were significantly associated with 1-yr mortality. However, LVEF (HR, 0.7–6.8 for the 6 wk, P > 0.05; and HR, 0.4–3.2 for the 12 wk, P > 0.05) and LVFS (HR, 0.4–1.4 for the 6 wk; and 0.4–3.1 for the 12 wk, P > 0.05) did not predict late death. Chronic MR leads to LV anatomic and cellular remodeling and impaired contractility. The time course of LV remodeling and function changes in the rat model of MR is similar to humans. Prediction of outcome may be achieved by assessments of early LV remodeling.

  M Wang , D. C Hood , J. S Cho , Q Ghadiali , G. V De Moraes , X Zhang , R Ritch and J. M. Liebmann
 

Objective  To explore the feasibility of obtaining a local measurement of the thickness of the retinal ganglion cell layer in patients with glaucoma using frequency-domain optical coherence tomography (fdOCT) and a computer-aided manual segmentation procedure.

Methods  The fdOCT scans were obtained from the horizontal midline for 1 eye of 26 patients with glaucoma and 20 control subjects. The thickness of various layers was measured with a manual segmentation procedure aided by a computer program. The patients were divided into low- and high-sensitivity groups based on their foveal sensitivity on standard automated perimetry.

Results  The RGC plus inner plexiform and the retinal nerve fiber layers of the low-sensitivity group were significantly thinner than those of the high-sensitivity group. While these layers were thinner in the patients than the controls, the thicknesses of inner nuclear layer and receptor layer were similar in all 3 groups. Further, the thinning of the retinal ganglion cell plus inner plexiform layer in 1 glaucoma-affected eye showed qualitative correspondence to the loss in 10-2 visual field sensitivity.

Conclusions  Local measures of RGC layer thickness can be obtained from fdOCT scans using a manual segmentation procedure, and these measures show qualitative agreement with visual field sensitivity.

  Z Tian , T Ye , X Zhang , E Liu , W Wang , P Wang , G Liu , X Yang , G Hu and Z. Yu
 

Objective  To investigate the association between sleep duration and risk of hyperglycemia among preschool Chinese children.

Design  A population-based cross-sectional study.

Setting  Seventy-one randomly selected kindergartens in Tianjin, China.

Participants  Six hundred nineteen obese (body mass index z score ≥1.65) and 617 nonobese (body mass index z score <1.65) children aged 3 to 6 years were recruited and matched by age.

Main Exposure  Sleep duration.

Main Outcome Measures  Hyperglycemia, defined as a fasting glucose level of 100 mg/dL or higher.

Results  Obese children were more likely to have shorter sleep duration (≤8 hours) compared with their nonobese counterparts (P < .001). Compared with those who slept for 9 or 10 hours per night, those who slept for 8 hours or less had a significantly higher likelihood of having hyperglycemia, controlling for age and sex (odds ratio [OR], 1.65; 95% confidence interval [CI], 1.12-2.45). After further adjustment for other potential confounders, the association still remained statistically significant (OR, 1.64; 95% CI, 1.09-2.46). In the stratified multivariable analyses, those who were obese and slept for 8 hours or less had an increased risk of having hyperglycemia (OR, 2.12; 95% CI, 1.06-4.21) compared with those who were nonobese and slept for 9 hours or more.

Conclusions  Shorter sleep duration is associated with an increased risk of having hyperglycemia among preschool Chinese children. Whether adequate sleep may help maintain euglycemia among children, especially for those who are overweight or obese, warrants further investigation.

  X Zhang , X Wei , L Liu , G. P Marti , M. S Ghanamah , M. J Arshad , L Strom , R Spence , J Jeng , S Milner , J. W Harmon and G. L. Semenza
 

Objective  To perform a systematic exploration of the phenomenon of mobilization of circulating angiogenic cells (CACs) in an animal model. This phenomenon has been observed in patients with cutaneous burn wounds and may be an important mechanism for vasculogenesis in burn wound healing.

Design  We used a murine model, in which burn depth can be varied precisely, and a validated culture method for quantifying circulating CACs.

Setting  Michael D. Hendrix Burn Research Center, Baltimore, Maryland.

Participants  Male 129S1/SvImJ mice, aged 8 weeks, and 31 patients aged 19-59 years with burn injury on 1% to 64% of the body surface area and evidence of hemodynamic stability.

Main Outcome Measures  Burn wound histological features, including immunohistochemistry for blood vessels with CD31 and -smooth muscle actin antibodies, blood flow measured with laser Doppler perfusion imaging, and mobilization of CACs into circulating blood measured with a validated culture technique.

Results  Increasing burn depth resulted in a progressive delay in the time to mobilization of circulating CACs and reduced mobilization of CACs. This delay and reduction in CAC mobilization was associated with reduced perfusion and vascularization of the burn wound tissue. Analysis of CACs in the peripheral blood of the human patients, using a similar culture assay, confirmed results previously obtained by flow cytometry, that CAC levels peak early after the burn wound.

Conclusion  If CAC mobilization and wound perfusion are important determinants of clinical outcome, then strategies designed to augment angiogenic responses may improve outcome in patients with severe burn wounds.

Trial Registration  clinicaltrials.gov Identifier: NCT00796627

  L Wang , B Wu , Y Sun , T Xu , X Zhang , M Zhou and W. Jiang
  Background

Previous studies have indicated that protein kinase C (PKC) may enhance endothelial nitric oxide synthase (eNOS) activation, although the detailed mechanism(s) remains unclear. In this study, we investigated the roles of PKC isoforms in regulating propofol-induced eNOS activation in human umbilical vein endothelial cells (HUVECs).

Methods

We applied western blot (WB) analysis to investigate the effects of propofol on Ser1177 phosphorylation-dependent eNOS activation in HUVECs. Nitrite (NO2) accumulation was measured using the Griess assay. The phosphatidylinositol 3-kinase/Akt (PI3K/Akt) pathway was examined by WB assay. Propofol-induced translocation of individual PKC isoforms in subcellular fractions in HUVECs was analysed using WB assay.

Results

In HUVECs, protocol treatment (1–100 µM) for 10 min induced a concentration-dependent increase in phosphorylation of eNOS at Ser1177. The NO production was also increased accordingly. PKC inhibitors, bisindolylmaleimide I (0.1–1 µM), and staurosporine (20 and 100 nM), effectively blocked propofol-induced eNOS activation and NO production. Further analyses in fractionated endothelial lysate showed that short-term propofol treatment (50 µM) led to translocation of PKC-, PKC-, PKC-, PKC-, and PKC- from cytosolic to membrane fractions, which could also be inhibited by both PKC inhibitors. These data revealed that the differential redistribution of these isozymes is indispensable for propofol-induced eNOS activation. In addition, Akt was not phosphorylated in response to propofol at Ser473 or Thr308.

Conclusions

Propofol induces the Ser1177 phosphorylation-dependent eNOS activation through the drug-stimulated translocation of PKC isoforms to distinct intracellular sites in HUVECs, which is independent of PI3K/Akt-independent pathway.

  M. Z Fang , X Zhang and H. Zarbl
 

Epidemiologic and animal studies indicate that disruption of circadian rhythm increases breast cancer risk. Previously, we showed that methylselenocysteine reduced the incidence of N-nitroso-N-methylurea (NMU)–induced mammary carcinomas in Fischer 344 rats by 63%. Methylselenocysteine also increased the expression of Period 2 (Per2) and D-binding protein (DBP), providing evidence for a link between circadian rhythm and chemoprevention. Here, we report that NMU disrupted the expression of core circadian genes (Per1, Per2, Cry1, Cry2, and RevErbA) and circadian-controlled genes, including melatonin receptor 1 (MTNR1A), estrogen receptors (ER and ERβ), and growth-regulatory genes (Trp53, p21, Gadd45, and c-Myc) in mammary glands of Fischer 344 rats. By contrast, dietary methylselenocysteine (3 ppm selenium) given for 30 days, significantly enhanced the circadian expression of these genes (except for Cry1 and Cry2). The largest effect was on the levels of the Per2, MTNR1A, and ERβ mRNAs, which showed 16.5-fold, 4.7-fold, and 9.5-fold increases in their rhythm-adjusted means, respectively, and 44.5-fold, 6.5-fold, and 9.7-fold increases in amplitude as compared with the control diet, respectively. Methylselenocysteine also shifted the peak expression times of these genes to Zeitgeber time 12 (ZT12; lights off). Methylselenocysteine also induced rhythmic expression of Trp53, p21, and Gadd45 mRNAs with peak levels at ZT12, when c-Myc expression was at its lowest level. However, methylselenocysteine had no significant effect on the circadian expression of these genes in liver. These results suggest that dietary methylselenocysteine counteracted the disruptive effect of NMU on circadian expression of genes essential to normal mammary cell growth and differentiation. Cancer Prev Res; 3(5); 640–52. ©2010 AACR.

  M Chen , M. A. T Hildebrandt , J Clague , A. M Kamat , A Picornell , J Chang , X Zhang , J Izzo , H Yang , J Lin , J Gu , S Chanock , M Kogevinas , N Rothman , D. T Silverman , M Garcia Closas , H. B Grossman , C. P Dinney , N Malats and X. Wu
 

Sonic hedgehog (Shh) pathway genetic variations may affect bladder cancer risk and clinical outcomes. Therefore, we genotyped 177 single-nucleotide polymorphisms (SNP) in 11 Shh pathway genes in a study including 803 bladder cancer cases and 803 controls. We assessed SNP associations with cancer risk and clinical outcomes in 419 cases of non–muscle-invasive bladder cancer (NMIBC) and 318 cases of muscle-invasive and metastatic bladder cancer (MiMBC). Only three SNPs (GLI3 rs3823720, rs3735361, and rs10951671) reached nominal significance in association with risk (P ≤ 0.05), which became nonsignificant after adjusting for multiple comparisons. Nine SNPs reached a nominally significant individual association with recurrence of NMIBC in patients who received transurethral resection (TUR) only (P ≤ 0.05), of which two (SHH rs1233560 and GLI2 rs11685068) were replicated independently in 356 TUR-only NMIBC patients, with P values of 1.0 x 10–3 (SHH rs1233560) and 1.3 x 10–3 (GLI2 rs11685068). Nine SNPs also reached a nominally significant individual association with clinical outcome of NMIBC patients who received Bacillus Calmette-Guérin (BCG; P ≤ 0.05), of which two, the independent GLI3 variants rs6463089 and rs3801192, remained significant after adjusting for multiple comparisons (P = 2 x 10–4 and 9 x 10–4, respectively). The wild-type genotype of either of these SNPs was associated with a lower recurrence rate and longer recurrence-free survival (versus the variants). Although three SNPs (GLI2 rs735557, GLI2 rs4848632, and SHH rs208684) showed nominal significance in association with overall survival in MiMBC patients (P ≤ 0.05), none remained significant after multiple-comparison adjustments. Germ-line genetic variations in the Shh pathway predicted clinical outcomes of TUR and BCG for NMIBC patients. Cancer Prev Res; 3(10); 1235–45. ©2010 AACR.

  T Melkamu , X Zhang , J Tan , Y Zeng and F. Kassie
 

MicroRNAs (miRNAs) are small, non-protein-coding RNAs that can function as tumor suppressors or oncogenes. Deregulation of miRNA expression has been reported in lung cancer. However, modulation of miRNA expression by chemopreventive agents remains to be defined. In the present study, we examined if the chemopreventive agent indole-3-carbinol (I3C) reversed vinyl carbamate (VC)-induced deregulation of miRNA levels in lung tissues of female A/J mice. Lung tissues were obtained from a previous chemoprevention study, in which mice were treated with VC and given I3C in the diet for 15 weeks. Microarray studies revealed alterations in the expression of a number of miRNAs in lung tumors relative to that of normal lungs. miR-21, mir-31, miR-130a, miR-146b and miR-377 were consistently upregulated, whereas miR-1 and miR-143 were downregulated in lung tumors relative to normal lungs. In mice treated with VC and given I3C in the diet, levels of miR-21, mir-31, miR-130a, miR-146b and miR-377 were reduced relative to the level in mice treated with the carcinogen only. The results of the microarray study were confirmed by quantitative reverse transcription–polymerase chain reaction and gel analysis of polymerase chain reaction products. Further studies with miR-21 indicated that phosphatase and tensin homolog, programmed cell death 4 and rich protein with Kazal motifs are potential targets for the oncogenic effect of miR-21 and the chemopreventive activity of I3C. Taken together, we showed here that miRNAs are deregulated during VC-induced mouse lung tumorigenesis and their levels are modulated by I3C. Therefore, miRNAs and their target genes are promising biomarkers for the diagnosis of lung cancer and efficacy of chemopreventive/chemotherapeutic agents.

  Y Dong , B Lu , X Zhang , J Zhang , L Lai , D Li , Y Wu , Y Song , J Luo , X Pang , Z Yi and M. Liu
 

Cucurbitacin E (CuE, -elaterin), a tetracyclic triterpenes compound from folk traditional Chinese medicine plants, has been shown to inhibit cancer cell growth, inflammatory response and bilirubin–albumin binding. However, the effects of CuE on tumor angiogenesis and its potential molecular mechanism are still unknown. Here, we demonstrated that CuE significantly inhibited human umbilical vascular endothelial cell (HUVEC) proliferation, migration and tubulogenesis in vitro and blocked angiogenesis in chick embryo chorioallantoic membrane assay and mouse corneal angiogenesis model in vivo. Furthermore, we found that CuE remarkably induced HUVEC apoptosis, inhibited tumor angiogenesis and suppressed human prostate tumor growth in xenograft tumor model. Finally, we showed that CuE blocked vascular endothelial growth factor receptor (VEGFR) 2-mediated Janus kinase (Jak) 2–signal transducer and activator of transcription (STAT) 3 signaling pathway in endothelial cells and suppressed the downstream protein kinases, such as extracellular signal-regulated kinase and p38 mitogen-activated protein kinases. Therefore, our studies provided the first evidence that CuE inhibited tumor angiogenesis by inhibiting VEGFR2-mediated Jak–STAT3 and mitogen-activated protein kinases signaling pathways and CuE is a potential candidate in angiogenesis-related disease therapy.

  X Zhang , H Yang , J. J Lee , E Kim , S. M Lippman , F. R Khuri , M. R Spitz , R Lotan , W. K Hong and X. Wu
 

Second primary tumor (SPT) and/or recurrence negatively impact the prognosis of patients with curatively treated early-stage head and neck cancer. MicroRNAs (miRNAs) play important roles in cancer development. We explored whether the variations of miRNA-related pathway were associated with the risk of SPT/recurrence in patients with early-stage head and neck cancer. This study includes 150 early-stage head and neck cancer patients with SPT/recurrence and 300 patients without SPT/recurrence. Two hundred and thirty-five tagging and potentially functional single-nucleotide polymorphisms (SNPs) were genotyped from eight miRNA biogenesis pathway genes and 135 miRNA-targeted genes. Eighteen miRNA-related SNPs were significantly associated with the risk of SPT/recurrence. The most significant SNP was rs3747238, a miRNA-binding site SNP in SMC1B. The variant homozygous genotype of this SNP was associated with a 1.74-fold increased risk [95% confidence interval (CI) 1.19–2.54; P = 0.004]. Cumulative effect analysis showed joint effects for the number of unfavorable genotype in patients. Survival tree analysis further identified the high-order gene–gene interactions and categorized the study subjects into low-, medium- and high-risk groups. Patients in the high-risk group had a 4.84-fold increased risk (95% CI: 3.11–7.51; P = 2.45 x 10–12) and a shorter event-free median survival time of 37.9 months (log rank P = 2.28 x 10–13). Our results suggested that miRNA-related genetic polymorphisms may be used individually and jointly to predict the risk of SPT/recurrence of early-stage head and neck cancer patients.

  X Zheng , D Lian , A Wong , M Bygrave , T. E Ichim , M Khoshniat , X Zhang , H Sun , T De Zordo , J. C Lacefield , B Garcia , A. M Jevnikar and W. P. Min
 

Background— Ischemia/reperfusion injury is a major factor in graft quality and subsequent function in the transplantation setting. We hypothesize that the process of RNA interference may be used to "engineer" a graft to suppress expression of genes associated with inflammation, apoptosis, and complement, which are believed to cause ischemia/reperfusion injury. Such manipulation of pathological gene expression may be performed by treatment of the graft ex vivo with small interfering RNA (siRNA) as part of the preservation procedure.

Methods and Results— Heart grafts from BALB/c mice were preserved in UW solution (control) or UW solution containing siRNAs targeting tumor necrosis factor-, C3, and Fas genes (siRNA solution) at 4°C for 48 hours and subsequently transplanted into syngeneic recipients. Tumor necrosis factor-, C3, and Fas genes were elevated by ischemia/reperfusion injury after 48 hours of preservation in UW solution. Preservation in siRNA solution knocked down gene expression at the level of messenger RNA and protein in the grafts after transplantation. All grafts preserved in siRNA solution showed strong contraction, whereas grafts preserved in control solution demonstrated no detectable contraction by high-frequency ultrasound scanning. siRNA solution–treated organs exhibited improved histology and diminished neutrophil and lymphocyte infiltration compared with control solution–treated organs. Furthermore, the treated heart grafts retained strong beating up to the end of the observation period (>100 days), whereas all control grafts lost function within 8 days.

Conclusion— Incorporation of siRNA into organ storage solution is a feasible and effective method of attenuating ischemia/reperfusion injury, protecting cardiac function, and prolonging graft survival.

  Y Sun , G Hu , X Zhang and R. D. Minshall
 

Rationale: Oxidants are important signaling molecules known to increase endothelial permeability, although the mechanisms underlying permeability regulation are not clear.

Objective: To define the role of caveolin-1 in the mechanism of oxidant-induced pulmonary vascular hyperpermeability and edema formation.

Methods and Results: Using genetic approaches, we show that phosphorylation of caveolin-1 Tyr14 is required for increased pulmonary microvessel permeability induced by hydrogen peroxide (H2O2). Caveolin-1–deficient mice (cav-1–/–) were resistant to H2O2-induced pulmonary vascular albumin hyperpermeability and edema formation. Furthermore, the vascular hyperpermeability response to H2O2 was completely rescued by expression of caveolin-1 in cav-1–/– mouse lung microvessels but was not restored by the phosphorylation-defective caveolin-1 mutant. The increase in caveolin-1 phosphorylation induced by H2O2 was dose-dependently coupled to both increased 125I-albumin transcytosis and decreased transendothelial electric resistance in pulmonary endothelial cells. Phosphorylation of caveolin-1 following H2O2 exposure resulted in the dissociation of vascular endothelial cadherin/β-catenin complexes and resultant endothelial barrier disruption.

Conclusions: Caveolin-1 phosphorylation–dependent signaling plays a crucial role in oxidative stress-induced pulmonary vascular hyperpermeability via transcellular and paracellular pathways. Thus, caveolin-1 phosphorylation may be an important therapeutic target for limiting oxidant-mediated vascular hyperpermeability, protein-rich edema formation, and acute lung injury.

  W Ma , H Kantarjian , B Bekele , A. C Donahue , X Zhang , Z. J Zhang , S O`Brien , E Estey , Z Estrov , J Cortes , M Keating , F Giles and M. Albitar
 

Purpose: Cytogenetic abnormalities are currently the most important predictors of response and clinical outcome for patients with acute myeloid leukemia (AML) or advanced-stage myelodysplastic syndrome (MDS). Because clinical outcomes vary markedly within cytogenetic subgroups, additional biological markers are needed for risk stratification.

Experimental Design: We assessed the utility of measuring pretreatment proteasome chymotrypsin-like, caspase-like, and trypsin-like activities in plasma to predict response and survival of patients with AML (n = 174) or advanced-stage MDS (n = 52).

Results: All three enzymatic activities were significantly (P < 0.001) increased in the plasma of patients with AML and MDS compared with normal controls. Both chymotrypsin-like and caspase-like activities, but not trypsin-like activity, correlated with outcome. Chymotrypsin-like and caspase-like activities, but not trypsin-like activity, predicted response in univariate analysis (P = 0.002). However, only chymotrypsin-like activity was independent predictor of response from age grouping (<70 versus ≥70 years), cytogenetics, and blood urea nitrogen in multivariate analysis. Similarly, both chymotrypsin-like and caspase-like activities, but not trypsin-like activity, were predictors of overall survival in univariate analysis (P < 0.0001), but only chymotrypsin-like activity was independent of cytogenetics, age, performance status, blood urea nitrogen, and β2-microglobulin in multivariate Cox regression models. Chymotrypsin-like activity was also a strong independent predictor of survival in patients with intermediate karyotype (n = 124).

Conclusions: Measuring plasma chymotrypsin-like activity may provide a powerful biomarker for risk stratification in patients with AML and advanced-stage MDS, including those with normal karyotype.

  L. S Chou , C. S. J Liu , B Boese , X Zhang and R. Mao
 

Background: The introduction and use of next-generation sequencing (NGS) techniques have taken genomic research into a new era; however, implementing such powerful techniques in diagnostics laboratories for applications such as resequencing of targeted disease genes requires attention to technical issues, including sequencing template enrichment, management of massive data, and high interference by homologous sequences.

Methods: In this study, we investigated a process for enriching DNA samples that uses a customized high-density oligonucleotide microarray to enrich a targeted 280-kb region of the NF1 (neurofibromin 1) gene. The captured DNA was sequenced with the Roche/454 GS FLX system. Two NF1 samples (CN1 and CN2) with known genotypes were tested with this protocol.

Results: Targeted microarray capture may also capture sequences from nontargeted regions in the genome. The capture specificity estimated for the targeted NF1 region was approximately 60%. The de novo Alu insertion was partially detected in sample CN1 by additional de novo assembly with 50% base-match stringency; the single-base deletion in sample CN2 was successfully detected by reference mapping. Interferences by pseudogene sequences were removed by means of dual-mode reference-mapping analysis, which reduced the risk of generating false-positive data. The risk of generating false-negative data was minimized with higher sequence coverage (>30x).

Conclusions: We used a clinically relevant complex genomic target to evaluate a microarray-based sample-enrichment process and an NGS instrument for clinical resequencing purposes. The results allowed us to develop a systematic data-analysis strategy and algorithm to fit potential clinical applications.

  M Zappitelli , X Zhang and B. J. Foster
 

Background and objectives: Estimation of GFR in children from serum creatinine measures in regional databases is limited by a lack of height data. Furthermore, the ability of GFR estimating equations to quantify changes in GFR over time is unknown. Two methods of estimating GFR when height is unknown and the ability of several GFR equations to quantify GFR changes over time were evaluated.

Design, setting, participants & measurements: This retrospective study included 195 children (mean age 11.9 ± 4.6 years, GFR = 78.8 ± 34.5) who underwent iothalamate GFR, serum creatinine, and height measurements; 93 children underwent a second GFR measurement and 47 a third GFR measurement. Four equations were evaluated for bias and precision and for quantifying GFR change over time: (1) Schwartz, using measured height; (2) Schwartz, using estimated height (based on previous height percentile); (3) a locally derived modification of a previously derived height-independent equation.

Results: The Schwartz (measured height) displayed the least bias (–2 to +7%), followed by the modified height-independent equation and Schwartz (estimated height). All equations were imprecise. All equations performed similarly at capturing change in measured GFR over time, with no significant difference between estimated and measured GFR percentage change over time. The height-estimated Schwartz formula performed similarly to the height-measured Schwartz in all aspects of equation performance.

Conclusions: Pediatric GFR follow-up studies may be possible using height-independent equations. Estimating height from prior height measurements enhances GFR estimation when height is unknown. These findings will hopefully help advance future pediatric renal function database studies.

  A Liu , A. D Patterson , Z Yang , X Zhang , W Liu , F Qiu , H Sun , K. W Krausz , J. R Idle , F. J Gonzalez and R. Dai
 

Fenofibrate, widely used for the treatment of dyslipidemia, activates the nuclear receptor, peroxisome proliferator-activated receptor . However, liver toxicity, including liver cancer, occurs in rodents treated with fibrate drugs. Marked species differences occur in response to fibrate drugs, especially between rodents and humans, the latter of which are resistant to fibrate-induced cancer. Fenofibrate metabolism, which also shows species differences, has not been fully determined in humans and surrogate primates. In the present study, the metabolism of fenofibrate was investigated in cynomolgus monkeys by ultraperformance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-QTOFMS)-based metabolomics. Urine samples were collected before and after oral doses of fenofibrate. The samples were analyzed in both positive-ion and negative-ion modes by UPLC-QTOFMS, and after data deconvolution, the resulting data matrices were subjected to multivariate data analysis. Pattern recognition was performed on the retention time, mass/charge ratio, and other metabolite-related variables. Synthesized or purchased authentic compounds were used for metabolite identification and structure elucidation by liquid chromatographytandem mass spectrometry. Several metabolites were identified, including fenofibric acid, reduced fenofibric acid, fenofibric acid ester glucuronide, reduced fenofibric acid ester glucuronide, and compound X. Another two metabolites (compound B and compound AR), not previously reported in other species, were characterized in cynomolgus monkeys. More importantly, previously unknown metabolites, fenofibric acid taurine conjugate and reduced fenofibric acid taurine conjugate were identified, revealing a previously unrecognized conjugation pathway for fenofibrate.

  A Liu , A. D Patterson , Z Yang , X Zhang , W Liu , F Qiu , H Sun , K. W Krausz , J. R Idle , F. J Gonzalez and R. Dai
 

Fenofibrate, widely used for the treatment of dyslipidemia, activates the nuclear receptor, peroxisome proliferator-activated receptor . However, liver toxicity, including liver cancer, occurs in rodents treated with fibrate drugs. Marked species differences occur in response to fibrate drugs, especially between rodents and humans, the latter of which are resistant to fibrate-induced cancer. Fenofibrate metabolism, which also shows species differences, has not been fully determined in humans and surrogate primates. In the present study, the metabolism of fenofibrate was investigated in cynomolgus monkeys by ultraperformance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-QTOFMS)-based metabolomics. Urine samples were collected before and after oral doses of fenofibrate. The samples were analyzed in both positive-ion and negative-ion modes by UPLC-QTOFMS, and after data deconvolution, the resulting data matrices were subjected to multivariate data analysis. Pattern recognition was performed on the retention time, mass/charge ratio, and other metabolite-related variables. Synthesized or purchased authentic compounds were used for metabolite identification and structure elucidation by liquid chromatographytandem mass spectrometry. Several metabolites were identified, including fenofibric acid, reduced fenofibric acid, fenofibric acid ester glucuronide, reduced fenofibric acid ester glucuronide, and compound X. Another two metabolites (compound B and compound AR), not previously reported in other species, were characterized in cynomolgus monkeys. More importantly, previously unknown metabolites, fenofibric acid taurine conjugate and reduced fenofibric acid taurine conjugate were identified, revealing a previously unrecognized conjugation pathway for fenofibrate.

  M. H Chen , C. W Wilson , Y. J Li , K. K. L Law , C. S Lu , R Gacayan , X Zhang , C. c Hui and P. T. Chuang
 

A central question in Hedgehog (Hh) signaling is how evolutionarily conserved components of the pathway might use the primary cilium in mammals but not fly. We focus on Suppressor of fused (Sufu), a major Hh regulator in mammals, and reveal that Sufu controls protein levels of full-length Gli transcription factors, thus affecting the production of Gli activators and repressors essential for graded Hh responses. Surprisingly, despite ciliary localization of most Hh pathway components, regulation of Gli protein levels by Sufu is cilium-independent. We propose that Sufu-dependent processes in Hh signaling are evolutionarily conserved. Consistent with this, Sufu regulates Gli protein levels by antagonizing the activity of Spop, a conserved Gli-degrading factor. Furthermore, addition of zebrafish or fly Sufu restores Gli protein function in Sufu-deficient mammalian cells. In contrast, fly Smo is unable to translocate to the primary cilium and activate the mammalian Hh pathway. We also uncover a novel positive role of Sufu in regulating Hh signaling, resulting from its control of both Gli activator and repressor function. Taken together, these studies delineate important aspects of cilium-dependent and cilium-independent Hh signal transduction and provide significant mechanistic insight into Hh signaling in diverse species.

  H. H Liu , P Lu , Y Guo , E Farrell , X Zhang , M Zheng , B Bosano , Z Zhang , J Allard , G Liao , S Fu , J Chen , K Dolim , A Kuroda , J Usuka , J Cheng , W Tao , K Welch , Y Liu , J Pease , S. A de Keczer , M Masjedizadeh , J. S Hu , P Weller , T Garrow and G. Peltz
 

Acetaminophen-induced liver toxicity is the most frequent precipitating cause of acute liver failure and liver transplant, but contemporary medical practice has mainly focused on patient management after a liver injury has been induced. An integrative genetic, transcriptional, and two-dimensional NMR-based metabolomic analysis performed using multiple inbred mouse strains, along with knowledge-based filtering of these data, identified betaine-homocysteine methyltransferase 2 (Bhmt2) as a diet-dependent genetic factor that affected susceptibility to acetaminophen-induced liver toxicity in mice. Through an effect on methionine and glutathione biosynthesis, Bhmt2 could utilize its substrate (S-methylmethionine [SMM]) to confer protection against acetaminophen-induced injury in vivo. Since SMM is only synthesized in plants, Bhmt2 exerts its beneficial effect in a diet-dependent manner. Identification of Bhmt2 and the affected biosynthetic pathway demonstrates how a novel method of integrative genomic analysis in mice can provide a unique and clinically applicable approach to a major public health problem.

  G Zhang , G Guo , X Hu , Y Zhang , Q Li , R Li , R Zhuang , Z Lu , Z He , X Fang , L Chen , W Tian , Y Tao , K Kristiansen , X Zhang , S Li , H Yang , J Wang and J. Wang
 

Understanding the dynamics of eukaryotic transcriptome is essential for studying the complexity of transcriptional regulation and its impact on phenotype. However, comprehensive studies of transcriptomes at single base resolution are rare, even for modern organisms, and lacking for rice. Here, we present the first transcriptome atlas for eight organs of cultivated rice. Using high-throughput paired-end RNA-seq, we unambiguously detected transcripts expressing at an extremely low level, as well as a substantial number of novel transcripts, exons, and untranslated regions. An analysis of alternative splicing in the rice transcriptome revealed that alternative cis-splicing occurred in ~33% of all rice genes. This is far more than previously reported. In addition, we also identified 234 putative chimeric transcripts that seem to be produced by trans-splicing, indicating that transcript fusion events are more common than expected. In-depth analysis revealed a multitude of fusion transcripts that might be by-products of alternative splicing. Validation and chimeric transcript structural analysis provided evidence that some of these transcripts are likely to be functional in the cell. Taken together, our data provide extensive evidence that transcriptional regulation in rice is vastly more complex than previously believed.

  Y He , Y Li , Z Peng , H Yu , X Zhang , L Chen , Q Ji , W Chen and R. Wang
 

A prominent feature of the rodent Muc3 SEA module is the precursor cleavage event that segregates the O-glycosylated N-terminal fragment and transmembrane domain into the noncovalently attached heterodimer. There are seven potential N-glycosylation sites that occur in a cluster in the SEA module of Muc3. However, it is unknown if these sites are modified or what the function of these N-glycans may be in the SEA module. Our data show that the proteolytic cleavage of the rodent Muc3 SEA module was partially prevented by treatment with tunicamycin, an inhibitor of N-glycosylation. Each single mutant of the seven N-glycosylation sites (N1A, N2A, N3A, N4A, N5A, N6A, and N7A) and multiple mutants, including double (N34A) and triple (N345A) mutants, and mutants with four (N3457A), five (N34567A), six (N134567A and N234567A), seven (N1234567A) mutations, confirmed that all seven of these potential sites are N-glycosylated simultaneously. The proteolytic cleavage of the SEA module was not affected when it lacked only one, two, or three N-glycans, but was partially inhibited when lacking four, five, and six N-glycans. In all, 2%, 48%, 85%, and 73% of the products from N3457A, N34567A, N134567A, and N234567A transfectants, respectively, remained uncleaved. The proteolytic cleavage was completely prevented in the N1234567A transfectant, which eliminated all seven N-glycans in the SEA module. The interaction of the heterodimer was independent of the N-glycans within the rodent Muc3 SEA module. Thus, the N-glycosylation pattern constituted a control point for the modulation of the proteolytic cleavage of the SEA module.

  E Sandwall , P O'Callaghan , X Zhang , U Lindahl , L Lannfelt and J. P. Li
 

Heparan sulfate (HS) has been found associated with amyloid deposits, including the toxic amyloid-beta (Aβ) peptide aggregates in cerebral vasculature and neuronal tissues in patients with Alzheimer's disease. However, the pathophysiological significance of the HS-Aβ interaction has remained unclear. In the present study, we applied cell models to gain insight into the roles of HS in relation to Aβ toxicity. Wild-type Chinese hamster ovary (CHO-WT) cells showed loss of viability following exposure to Aβ40, whereas the HS-deficient cell line, pgsD-677, was essentially resistant. Immunocytochemical analysis showed Aβ internalization by CHO-WT, but not pgsD-677 cells. Aβ40 toxicity was also attenuated in human embryonic kidney cells overexpressing heparanase. Finally, addition of heparin to human umbilical vein endothelial cells prevented internalization of added Aβ40 and protected against Aβ toxicity. Taken together, these findings suggest that cell-surface HS mediates Aβ internalization and toxicity.

  X Zhang , B Han , J Huang , B Zheng , Q Geng , F Aziz and Q. Dong
  Objective

The purpose of this study was to detect the presence of cancer stem-like cells with bronchioalveolar stem cells (BASCs) properties and investigate the clinicopathological role of expression of OCT4 as well as the correlation with clinical outcomes in adenocarcinoma of the lung.

Methods

Specimens of 112 cases of Stage IB–IIIA lung adenocarcinoma after radical surgery were collected from June 1999 to June 2002. The putative cancer stem cells in tumor sections were visualized immunofluorescently by using the antibodies against three bronchioalveolar stem cells markers: surfactant protein C (SPC), Clara cell secretary protein (CCSP) and Octamer-4 (OCT4). Cancer stem-like cells with bronchioalveolar stem cell properties in human lung adenocarcinoma were subdivided into two phenotypes: OCT4+BASC (SPC+CCSP+OCT4+) and OCT4BASC (SPC+CCSP+OCT4).

Results

Cancer cells with CCSP+SPC+BASC phenotype were detected in 107 cases, 80 cases with OCT4+BASC phenotype (SPC+CCSP+OCT4+) and 27 cases with SPC+CCSP+OCT4. There was a correlation between differentiation and OCT4 expression (P = 0.047). The pattern of survival curves shows the expected trend of decreasing survival with increasing stage at diagnosis (P = 0.015) and with OCT4+BASC expression (P = 0.019). Multivariate Cox's analysis reveals that pathological stages of TNM (P = 0.008) and bronchioalveolar stem cells phenotypes (P = 0.015) are the independent prognostic factors.

Conclusions

The cancer cells with bronchioalveolar stem cells phenotype are detectable in adenocarcinoma of the lung and the expression of self-renewal regulatory gene OCT4 in these cells indicated the worse clinical outcomes.

  X Zhang , Q Chen , J Feng , J Hou , F Yang , J Liu , Q Jiang and C. Zhang
 

Nedd1 is a new member of the -tubulin ring complex (TuRC) and targets the TuRC to the centrosomes for microtubule nucleation and spindle assembly in mitosis. Although its role is known, its functional regulation mechanism remains unclear. Here we report that the function of Nedd1 is regulated by Cdk1 and Plk1. During mitosis, Nedd1 is firstly phosphorylated at T550 by Cdk1, which creates a binding site for the polo-box domain of Plk1. Then, Nedd1 is further phosphorylated by Plk1 at four sites: T382, S397, S637 and S426. The sequential phosphorylation of Nedd1 by Cdk1 and Plk1 promotes its interaction with -tubulin for targeting the TuRC to the centrosome and is important for spindle formation. Knockdown of Plk1 by RNAi decreases Nedd1 phosphorylation and attenuates Nedd1 accumulation at the spindle pole and subsequent -tubulin recruitment at the spindle pole for microtubule nucleation. Taken together, we propose that the sequential phosphorylation...

  J Zhang , C Yu , Z Liao , X Zhang , L You and D. Yu
 

Mn-doped ZnO nanobelts have been synthesized via the vapor phase evaporation method, which exhibited ferromagnetism at room temperature. Electron energy-loss spectroscopy was used to investigate the chemical state of Mn dopants. It revealed that the Mn species had the chemical valence of +2. Meanwhile, the fine structures of the Mn L23 edges indicated that the Mn dopant was located at the center of an oxygen octahedron but not an oxygen tetrahedron. This suggested that the Mn dopants did not substitute on the Zn sites as expected and sub-nanoscale MnO clusters had been formed in the synthesized ZnO nanobelts.

  X Zhang , L Wang , A Lu and M. Zhang
 

Objective: To summarize the clinical characteristics of idiopathic pulmonary haemosiderosis (IPH) to explore the aetiopathogenesis, risk factors, diagnosis and experiences in therapy of IPH. Methods: The documents of 28 IPH cases, who were hospitalized in Children’s Hospital of Fudan University between February 1989 and June 2009 were reviewed. Results: (i) fifteen cases were males and 13 were females, and 88.5% of the cases had first onset under the age of 10 years; (ii) the triad occurred in 57.1% cases; (iii) radiographic features of IPH including diffuse alveolar-type infiltrates, ground glass attenuation, interstitial reticular and micronodular patterns; (iv) haemosiderin-laden macrophages were found in 60.7% of the cases;(v) the trend of positive correlation was found between the severity of ventilatory restrictive pattern and the disease courses (r = 0.229, p = 0.237); and (vi) glucocorticosteroids can control the symptoms. Conclusion: (i) the clinical presentations are not classical. If long-term anaemia exists without reason, this case must be considered; (ii) corticosteroid can control the symptom; and (iii) IPH may be associated with the imbalance of immune system.

  L Kang , X Zhang , Y Xie , Y Tu , D Wang , Z Liu and Z. Y. Wang
 

Accumulating evidence suggested that an orphan G protein-coupled receptor (GPR)30, mediates nongenomic responses to estrogen. The present study was performed to investigate the molecular mechanisms underlying GPR30 function. We found that knockdown of GPR30 expression in breast cancer SK-BR-3 cells down-regulated the expression levels of estrogen receptor (ER)-36, a variant of ER-. Introduction of a GPR30 expression vector into GPR30 nonexpressing cells induced endogenous ER-36 expression, and cotransfection assay demonstrated that GPR30 activated the promoter activity of ER-36 via an activator protein 1 binding site. Both 17β-estradiol (E2) and G1, a compound reported to be a selective GPR30 agonist, increased the phosphorylation levels of the MAPK/ERK1/2 in SK-BR-3 cells, which could be blocked by an anti-ER-36-specific antibody against its ligand-binding domain. G1 induced activities mediated by ER-36, such as transcription activation activity of a VP16-ER-36 fusion protein and activation of the MAPK/ERK1/2 in ER-36-expressing cells. ER-36-expressing cells, but not the nonexpressing cells, displayed high-affinity, specific E2 and G1 binding, and E2- and G1-induced intracellular Ca2+ mobilization only in ER-36 expressing cells. Taken together, our results demonstrated that previously reported activities of GPR30 in response to estrogen were through its ability to induce ER-36 expression. The selective G protein-coupled receptor (GPR)30 agonist G1 actually interacts with ER-36. Thus, the ER- variant ER-36, not GPR30, is involved in nongenomic estrogen signaling.

  L Yu , J. E Coelho , X Zhang , Y Fu , A Tillman , U Karaoz , B. B Fredholm , Z Weng and J. F. Chen
 

Caffeine is the most widely consumed psychoactive substance and has complex pharmacological actions in brain. In this study, we employed a novel drug target validation strategy to uncover the multiple molecular targets of caffeine using combined A2A receptor (A2AR) knockouts (KO) and microarray profiling. Caffeine (10 mg/kg) elicited a distinct profile of striatal gene expression in WT mice compared with that by A2AR gene deletion or by administering caffeine into A2AR KO mice. Thus, A2ARs are required but not sufficient to elicit the striatal gene expression by caffeine (10 mg/kg). Caffeine (50 mg/kg) induced complex expression patterns with three distinct sets of striatal genes: 1) one subset overlapped with those elicited by genetic deletion of A2ARs; 2) the second subset elicited by caffeine in WT as well as A2AR KO mice; and 3) the third subset elicited by caffeine only in A2AR KO mice. Furthermore, striatal gene sets elicited by the phosphodiesterase (PDE) inhibitor rolipram and the GABAA receptor antagonist bicucullin, overlapped with the distinct subsets of striatal genes elicited by caffeine (50 mg/kg) administered to A2AR KO mice. Finally, Gene Set Enrichment Analysis reveals that adipocyte differentiation/insulin signaling is highly enriched in the striatal gene sets elicited by both low and high doses of caffeine. The identification of these distinct striatal gene populations and their corresponding multiple molecular targets, including A2AR, non-A2AR (possibly A1Rs and pathways associated with PDE and GABAAR) and their interactions, and the cellular pathways affected by low and high doses of caffeine, provides molecular insights into the acute pharmacological effects of caffeine in the brain.

  X Zhang , P Sebastiani , G Liu , F Schembri , Y. M Dumas , E. M Langer , Y Alekseyev , G. T O'Connor , D. R Brooks , M. E Lenburg and A. Spira
 

Previous studies have shown that physiological responses to cigarette smoke can be detected via bronchial airway epithelium gene expression profiling and that heterogeneity in this gene expression response to smoking is associated with lung cancer. In this study, we sought to determine the similarity of the effects of tobacco smoke throughout the respiratory tract by determining patterns of smoking-related gene expression in paired nasal and bronchial epithelial brushings collected from 14 healthy nonsmokers and 13 healthy current smokers. Using whole genome expression arrays, we identified 119 genes whose expression was affected by smoking similarly in both bronchial and nasal epithelium, including genes related to detoxification, oxidative stress, and wound healing. While the vast majority of smoking-related gene expression changes occur in both bronchial and nasal epithelium, we also identified 27 genes whose expression was affected by smoking more dramatically in bronchial epithelium than nasal epithelium. Both common and site-specific smoking-related gene expression profiles were validated using independent microarray datasets. Differential expression of select genes was also confirmed by RT-PCR. That smoking induces largely similar gene expression changes in both nasal and bronchial epithelium suggests that the consequences of cigarette smoke exposure can be measured in tissues throughout the respiratory tract. Our findings suggest that nasal epithelial gene expression may serve as a relatively noninvasive surrogate to measure physiological responses to cigarette smoke and/or other inhaled exposures in large-scale epidemiological studies.

  Y Ding , L Jiao , W Zhang , L Zhou , X Zhang and L. Zhang
 

Sucrose is a convenient, common, tissue-equivalent material suitable for electron paramagnetic resonance (EPR) dosimetry of ionising radiation. A number of publications have reported on the dosimetric properties of sucrose and their use in radiation accident dose reconstruction. However, previous studies did not include specially the description of measurement methods of sucrose by EPR. The aim of this work is to introduce particularly the EPR measurement methods of sucrose. In this regard, practical considerations of sample size, microwave power, modulation amplitude, EPR spectrum and signal stability are discussed.

  X Wei , X Zhang , L. M Flick , H Drissi , E. M Schwarz and R. J. O'Keefe
 

In prosthetic loosening, bone resorption is induced by wear debris particles generated from the artificial joint articulation. Our prior work showed that synovial-like fibroblasts respond to titanium particles by producing receptor activator of NF-B ligand (RANKL), a critical activator of osteoclastogenesis. While this effect occurs through a cyclooxygenase-2 (COX-2)-dependent pathway, the mechanism of COX-2 stimulation by titanium particles is not clear. Here we show that titanium particles induce COX-2 gene expression by activating NF-B signaling. Inhibitor of NF-B (IB) is degraded following particle treatment, permitting active NF-B to translocate to the nucleus where it interacts with the COX-2 promoter and drives transcription. NF-B activation is dependent on reactive oxygen species since antioxidants block the NF-B signaling induced by particles. Surprisingly, IB degradation is independent of IKK (IB kinase) and the 26S proteasome. Instead, calpain inhibitor can block the IB degradation induced by particles. Furthermore, the calpain-targeted COOH-terminal PEST sequence of IB is necessary for phosphorylation and degradation, consistent with a proteasome-independent mechanism of catabolism. Altogether, the data demonstrate a signaling pathway by which titanium particles induce oxidative stress, stimulate calpain-mediated NF-B activation, and activate target gene expression, including COX-2. These findings define important targets for osteolysis but may also have importance in other diseases where fibroblasts respond to environmental particles, including pulmonary diseases.

  X Zhang , N Cui , Z Wu , J Su , J. S Tadepalli , S Sekizar and C. Jiang
 

Rett syndrome caused by mutations in methyl-CpG-binding protein 2 (Mecp2) gene shows abnormalities in autonomic functions in which brain stem norepinephrinergic systems play an important role. Here we present systematic comparisons of intrinsic membrane properties of locus coeruleus (LC) neurons between Mecp2–/Y and wild-type (WT) mice. Whole cell current clamp was performed in brain slices of 3- to 4-wk-old mice. Mecp2–/Y neurons showed stronger inward rectification and had shorter time constant than WT cells. The former was likely due to overexpression of inward rectifier K+ (Kir)4.1 channel, and the latter was attributable to the smaller cell surface area. The action potential duration was prolonged in Mecp2–/Y cells with an extended rise time. This was associated with a significant reduction in the voltage-activated Na+ current density. After action potentials, >60% Mecp2–/Y neurons displayed fast and medium afterhyperpolarizations (fAHP and mAHP), while nearly 90% WT neurons showed only mAHP. The mAHP amplitude was smaller in Mecp2–/Y neurons. The firing frequency was higher in neurons with mAHP, and the frequency variation was greater in cells with both fAHP and mAHP in Mecp2–/Y mice. Small but significant differences in spike frequency adaptation and delayed excitation were found in Mecp2–/Y neurons. These results indicate that there are several electrophysiological abnormalities in LC neurons of Mecp2–/Y mice, which may contribute to the dysfunction of the norepinephrine system in Rett syndrome.

  Y Chen , C Qian , C Guo , F Ge , X Zhang , X Gao , S Shen , B Lian , K Kitazato , Y Wang and S. Xiong
 

Nucleoside diphosphate phosphate transferase A (NDPK-A) has been shown to play critical roles in the regulation of proliferation, differentiation, growth and apoptosis of cells. Our previous study suggested that the disulphide cross-linkage between cysteine 4 (C4) and cysteine 145 (C145) of NDPK-A might be a possible regulator of its activity. To confirm this hypothesis, the C145 residue of NDPK-A was mutated to serine, and the isomerization and biological activities of the mutant were investigated and compared with those of its wild-type counterpart. It was found the C145S mutation eliminated the intramolecular disulphide bond (DB) and prevented the formation of intermolecular DB, which was known to dissociate the hexameric NDPK-A into dimeric one. We also demonstrated that the C145S mutation didn’t affect the autologous hexamerization of this protein, and the mutant had increased bioactivities including phosphate transferase and DNase. These findings support the hypothesis that the formation of DBs in NDPK-A is involved in the regulation of the oligomerization and bioactivity of this multiple function protein, and that C145 is a key residue in the regulation of NDPK-A. In addition, the C145S mutant that we have constructed might be an attractive candidate for use in applications that require NDPK-A.

  J Yang , R Yoshida , Y Kariya , X Zhang , S Hashiguchi , T Nakashima , Y Suda , A Takada , Y Ito and K. Sugimura
 

The development of new therapeutic targets and strategies to control highly pathogenic avian influenza (HPAI) H5N1 virus infection in humans is urgently needed. Neutralizing recombinant human antibodies would provide important agents for immunotherapy on human H5N1 virus infection and definition of the critical mimotope for vaccine development. In this study, we have characterized an anti-H5-specific scFv clone, 3D1 from the human-scFv-displaying phage library. 3D1 blocked the binding of H5-Fc to MDCK cells in flow cytometry and neutralized H5N1 subtype influenza A viruses in a microneutralization assay. Employing a peptide-displaying phage library, Ph.D-12, the mimotope was determined to be at #128-131 and #204-211 of H5, which are silic acid-binding regions. In consistency with this result, 3D1 binds the recombinant sugar-binding domain (#50G-#272E) produced by a baculovirus vector. The 3D1 antibody employs the germline gene VH1-23. As this antibody is the first human anti-H5 scFv clearly defined on the sugar-binding epitope, it allows us to investigate the influence of amino acid substitutions in this region on the determination of the binding specificity to either sialic acid 2,6-galactose (SA 2,6Gal) or sialic acid 2,3-galactose (SA 2,3Gal) providing new insight for the development of effective H5N1 pandemic vaccines.

  X Shi , C Shao , X Zhang , C Zambonelli , A. G Redfield , J. F Head , B. A Seaton and M. F. Roberts
 

Cleavage of phosphatidylinositol (PI) to inositol 1,2-(cyclic)-phosphate (cIP) and cIP hydrolysis to inositol 1-phosphate by Bacillus thuringiensis phosphatidylinositol-specific phospholipase C are activated by the enzyme binding to phosphatidylcholine (PC) surfaces. Part of this reflects improved binding of the protein to interfaces. However, crystallographic analysis of an interfacially impaired phosphatidylinositol-specific phospholipase (W47A/W242A) suggested protein dimerization might occur on the membrane. In the W47A/W242A dimer, four tyrosine residues from one monomer interact with the same tyrosine cluster of the other, forming a tight dimer interface close to the membrane binding regions. We have constructed mutant proteins in which two or more of these tyrosine residues have been replaced with serine. Phospholipid binding and enzymatic activity of these mutants have been examined to assess the importance of these residues to enzyme function. Replacing two tyrosines had small effects on enzyme activity. However, removal of three or four tyrosine residues weakened PC binding and reduced PI cleavage by the enzyme as well as PC activation of cIP hydrolysis. Crystal structures of Y247S/Y251S in the absence and presence of myo-inositol as well as Y246S/Y247S/Y248S/Y251S indicate that both mutant proteins crystallized as monomers, were very similar to one another, and had no change in the active site region. Kinetic assays, lipid binding, and structural results indicate that either (i) a specific PC binding site, critical for vesicle activities and cIP activation, has been impaired, or (ii) the reduced dimerization potential for Y246S/Y247S/Y248S and Y246S/Y247S/Y248S/Y251S is responsible for their reduced catalytic activity in all assay systems.

  J Jia , M Maccarana , X Zhang , M Bespalov , U Lindahl and J. P. Li
 

HSEPI (glucuronyl C5-epimerase) catalyzes the conversion of d-glucuronic acid to l-iduronic acid in heparan sulfate (HS) biosynthesis. Disruption of the Hsepi gene in mice yielded a lethal phenotype with selective organ defects but had remarkably little effect on other organ systems. We have approached the underlying mechanisms by examining the course and effects of FGF2 signaling in a mouse embryonic fibroblast (MEF) cell line derived from the Hsepi/ mouse. The HS produced by these cells is devoid of l-iduronic acid residues but shows up-regulated N- and 6-O-sulfation compared with wild type (WT) MEF HS. In medium fortified with 10% fetal calf serum, the Hsepi/ MEFs proliferated and migrated similarly to WT cells. Under starvation conditions, both cell types showed attenuated proliferation and migration that could be restored by the addition of FGF2 to WT cells, whereas Hsepi/ cells were resistant. Moreover, ERK phosphorylation following FGF2 stimulation was delayed in Hsepi/ compared with WT cells. Assessment of HS-growth factor interaction by nitrocellulose filter trapping revealed a strikingly aberrant binding property of FGF2 and glia-derived neurotropic factor to Hsepi/ but not to WT HS. glia-derived neurotropic factor has a key role in kidney development, defective in Hsepi/ mice. By contrast, Hsepi/ and WT HS interacted similarly and in conventional mode with FGF10. These findings correlate defective function of growth factors with their mode of HS interaction and may help explain the partly modest organ phenotypes observed after genetic ablation of selected enzymes in HS biosynthesis.

  D Grandy , J Shan , X Zhang , S Rao , S Akunuru , H Li , Y Zhang , I Alpatov , X. A Zhang , R. A Lang , D. L Shi and J. J. Zheng
 

Dishevelled (Dvl) is an essential protein in the Wnt signaling pathways; it uses its PDZ domain to transduce the Wnt signals from the membrane receptor Frizzled to downstream components. Here, we report identifying a drug-like small molecule compound through structure-based ligand screening and NMR spectroscopy and show the compound to interact at low micromolar affinity with the PDZ domain of Dvl. In a Xenopus testing system, the compound could permeate the cell membrane and block the Wnt signaling pathways. In addition, the compound inhibited Wnt signaling and reduced the levels of apoptosis in the hyaloid vessels of eye. Moreover, this compound also suppressed the growth of prostate cancer PC-3 cells. These biological effects suggest that by blocking the PDZ domain of Dvl, the compound identified in our studies effectively inhibits the Wnt signaling and thus provides a useful tool for studies dissecting the Wnt signaling pathways.

 
 
 
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