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Articles by Z Sun
Total Records ( 4 ) for Z Sun
  X. P Huang , Z Sun , Y Miyagi , H McDonald Kinkaid , L Zhang , R. D Weisel and R. K. Li
  Background—

Cardiac cell therapy for older patients who experience a myocardial infarction may require highly regenerative cells from young, healthy (allogeneic) donors. Bone marrow mesenchymal stem cells (MSCs) are currently under clinical investigation because they can induce cardiac repair and may also be immunoprivileged (suitable for allogeneic applications). However, it is unclear whether allogeneic MSCs retain their immunoprivilege or functional efficacy late after myocardial implantation. We evaluated the effects of MSC differentiation on the immune characteristics of cells in vitro and in vivo and monitored cardiac function for 6 months after post–myocardial infarction MSC therapy.

Methods and Results—

In the in vitro experiments, inducing MSCs to acquire myogenic, endothelial, or smooth muscle characteristics (via 5-azacytidine or cytokine treatment) increased major histocompatibility complex-Ia and -II (immunogenic) expression and reduced major histocompatibility complex-Ib (immunosuppressive) expression, in association with increased cytotoxicity in coculture with allogeneic leukocytes. In the in vivo experiments, we implanted allogeneic or syngeneic MSCs into infarcted rat myocardia. We measured cell differentiation and survival (immunohistochemistry, real-time polymerase chain reaction) and cardiac function (echocardiography, pressure-volume catheter) for 6 months. MSCs (versus media) significantly improved ventricular function for at least 3 months after implantation. Allogeneic (but not syngeneic) cells were eliminated from the heart by 5 weeks after implantation, and their functional benefits were lost within 5 months.

Conclusions—

The long-term ability of allogeneic MSCs to preserve function in the infarcted heart is limited by a biphasic immune response whereby they transition from an immunoprivileged to an immunogenic state after differentiation, which is associated with an alteration in major histocompatibility complex–immune antigen profile.

  Y Wang , M Zhang , C Moon , Q Hu , B Wang , G Martin , Z Sun and H. Wang
 

FE65 is expressed predominantly in the brain and interacts with the C-terminal domain of β-amyloid precursor protein (APP). We examined hippocampus-dependent memory and in vivo long-term potentiation (LTP) at the CA1 synapses with isoform-specific FE65 knockout (p97FE65–/–) mice. When examined using the Morris water maze, p97FE65–/– mice were impaired for the hidden platform task but showed normal performance in the probe test. To further discriminate the role of FE65 in acquisition and memory consolidation, we examined p97FE65–/– mice with temporal dissociative passive avoidance (TDPA) and contextual fear conditioning (CFC). p97FE65–/– mice showed impaired short-term memory for both TDPA and CFC when tested 10 min after training. After multiple TDPA training sessions, the crossover latency of some p97FE65–/– mice reached the cutoff value, but it significantly decayed in 8 d. At the Schaffer collateral-CA1 synapses, p97FE65–/– mice showed defective early-phase LTP (E-LTP). These results demonstrate novel roles of FE65 in synaptic plasticity, acquisition, and retention for certain forms of memory formation.

  J Fourcade , Z Sun , M Benallaoua , P Guillaume , I. F Luescher , C Sander , J. M Kirkwood , V Kuchroo and H. M. Zarour
 

The paradoxical coexistence of spontaneous tumor antigen–specific immune responses with progressive disease in cancer patients furthers the need to dissect the molecular pathways involved in tumor-induced T cell dysfunction. In patients with advanced melanoma, we have previously shown that the cancer-germline antigen NY-ESO-1 stimulates spontaneous NY-ESO-1–specific CD8+ T cells that up-regulate PD-1 expression. We also observed that PD-1 regulates NY-ESO-1–specific CD8+ T cell expansion upon chronic antigen stimulation. In the present study, we show that a fraction of PD-1+ NY-ESO-1–specific CD8+ T cells in patients with advanced melanoma up-regulates Tim-3 expression and that Tim-3+PD-1+ NY-ESO-1–specific CD8+ T cells are more dysfunctional than Tim-3PD-1+ and Tim-3PD-1 NY-ESO-1–specific CD8+ T cells, producing less IFN-, TNF, and IL-2. Tim-3–Tim-3L blockade enhanced cytokine production by NY-ESO-1–specific CD8+ T cells upon short ex vivo stimulation with cognate peptide, thus enhancing their functional capacity. In addition, Tim-3–Tim-3L blockade enhanced cytokine production and proliferation of NY-ESO-1–specific CD8+ T cells upon prolonged antigen stimulation and acted in synergy with PD-1–PD-L1 blockade. Collectively, our findings support the use of Tim-3–Tim-3L blockade together with PD-1–PD-L1 blockade to reverse tumor-induced T cell exhaustion/dysfunction in patients with advanced melanoma.

 
 
 
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