Chung Yuan-Chang, Ma Ming-Chieh, Huang Bo-Yang, Chiang Han-Sun, Chou Shiu-Huey
Department of Medical Research, Tao-Yuan General Hospital, Taoyuan, Taiwan, Republic of China.
Chin J Physiol. 2011 Jun 30;54(3):169-82. doi: 10.4077/cjp.2011.amm019.
Non-hematopoietic CD45+ precursor cells are not known to differentiate into cardiomyocytes. We found that CD45+/CD34-/lin- stromal cells isolated from mouse bone marrow (BMSCs) potentially differentiated into cardiomyocyte-like cells in vitro. Therefore, we hypothesized that the CD45+/CD34-/ lin- BMSCs might protect rat hearts against ischemia/reperfusion (IR) injury following xeno-transplantation. In the present study, BMSCs were isolated by immunoselection and their cellular phenotype and biochemical properties were characterized. The immunological inertness of BMSCs was examined by the allogeneic and xenogeneic mixed lymphocyte reaction (MLR). The potential role of BMSCs for cardioprotection was evaluated by intravenous introduction of 1 x 10(6) cells into rat IR hearts, induced by left coronary ligation for 45 min and released for 72 h. Changes in cardiac contractility and the degree of myocardial injury were assessed. Our findings indicated that BMSCs expressed the muscle-cell marker alpha-actinin after 5-azacytidine treatment. CD45+/CD34-/lin- stromal cells were characterized as mesenchymal progenitor cells based on the expression of Sca-1 and Rex-1. The MLR assay revealed an immunosuppression of BMSCs on mouse and rat lymphocytes. After xeno-transplantation, the BMSCs engrafted into the infarct area and attenuated IR injury. However, increases in intracardial TGF-beta and IFN-gamma contents of IR hearts were not affected by BMSC treatment. Interestingly, ex vivo evidence indicated that CXCR4, SDF-1 and TGFbeta-1 receptors were up-regulated after the cells were exposed to tissue extracts prepared from rat post-IR hearts. In addition, IFN-gamma treatment also markedly increased Sca-1 expression in BMSCs. Mechanistically, these results indicated that CXCR4/SDF-1 and TGF-beta signals potentially enhanced the interaction of BMSCs with the damaged myocardium, and increased IFN-gamma in post-ischemic hearts might cause BMSC to behave more like stem cells in cardioprotection. These data show that CD45+/CD34-/lin- BMSCs possess cardioprotective capacity. Evidently, the accurate production of soluble factors TGF-beta and IFN-gamma in parallel with increased expression of both TGF-beta and Sca-1 receptors may favor BMSCs to achieve a more efficient protective capacity.
已知非造血性CD45 +前体细胞不会分化为心肌细胞。我们发现，从小鼠骨髓中分离出的CD45 + / CD34 - / lin - 基质细胞（BMSCs）在体外有可能分化为心肌样细胞。因此，我们推测CD45 + / CD34 - / lin - BMSCs可能在异种移植后保护大鼠心脏免受缺血/再灌注（IR）损伤。在本研究中，通过免疫筛选分离出BMSCs，并对其细胞表型和生化特性进行了表征。通过同种异体和异种混合淋巴细胞反应（MLR）检测BMSCs的免疫惰性。通过将1×10（6）个细胞静脉注射到大鼠IR心脏中来评估BMSCs的心脏保护作用，该心脏通过左冠状动脉结扎45分钟并再灌注72小时诱导产生。评估心脏收缩力的变化和心肌损伤程度。我们的研究结果表明，5-氮杂胞苷处理后BMSCs表达肌肉细胞标志物α-肌动蛋白。基于Sca-1和Rex-1的表达，CD45 + / CD34 - / lin - 基质细胞被表征为间充质祖细胞。MLR分析显示BMSCs对小鼠和大鼠淋巴细胞具有免疫抑制作用。异种移植后，BMSCs植入梗死区域并减轻IR损伤。然而，IR心脏中心脏内TGF-β和IFN-γ含量的增加不受BMSC治疗的影响。有趣的是，体外证据表明，细胞暴露于大鼠IR心脏后制备的组织提取物后，CXCR4、SDF-1和TGFβ-1受体上调。此外，IFN-γ处理也显著增加了BMSCs中Sca-1的表达。从机制上讲，这些结果表明CXCR4 / SDF-1和TGF-β信号可能增强BMSCs与受损心肌的相互作用，并且缺血后心脏中IFN-γ的增加可能导致BMSCs在心脏保护中表现得更像干细胞。这些数据表明CD45 + / CD34 - / lin - BMSCs具有心脏保护能力。显然，可溶性因子TGF-β和IFN-γ的准确产生以及TGF-β和Sca-1受体表达的增加可能有利于BMSCs实现更有效的保护能力。
