Introduction Despite major leaps in regenerative medicine, the regeneration of cardiomyocytes after ischemic conditions remains to elucidate. It is crucial to understand hypoxia induced cellular mechanisms to provide advanced treatment options, including the use of stem cell paracrine factors for myocardial regeneration. Materials and Methods In this study, the regenerative potential of hypoxic human cardiomyocytes (group Hyp-CMC) in vitro was evaluated when co-cultured with human bone-marrow derived MSC (group Hyp-CMC-MSC) or stimulated with the secretome of MSC (group Hyp-CMC-SMSC). The secretome of normoxic MSC and CMC, and the hypoxic CMC was analyzed with a cytokine panel. Gene expression changes of HIF-1α, proliferation marker Ki-67 and cytokinesis marker RhoA over different reoxygenation time periods of 4, 8, 24, 48, and 72 h were analyzed in comparison to normoxic CMC and MSC. Further, the proinflammatory cytokine IL-18 protein expression change, metabolic activity and proliferation was assessed in all experimental setups. Results and Conclusion HIF-1α was persistently overexpressed in Hyp-CMC-SMSC as compared to Hyp-CMC (except at 72 h). Hyp-CMC-MSC showed a weaker HIF-1α expression than Hyp-CMC-SMSC in most tested time points, except after 8 h. The Ki-67 expression showed the strongest upregulation in Hyp-CMC after 24 and 48 h incubation, then returned to baseline level, while a temporary increase in Ki-67 expression in Hyp-CMC-MSC at 4 and 8 h and at 48 h in Hyp-CMC-SMSC could be observed. RhoA was increased in normoxic MSCs and in Hyp-CMC-SMSC over time, but not in Hyp-CMC-MSC. A temporary increase in IL-18 protein expression was detected in Hyp-CMC-SMSC and Hyp-CMC. Our study demonstrates timely dynamic changes in expression of different ischemia and regeneration-related genes of CMCs, depending from the culture condition, with stronger expression of HIF-1α, RhoA and IL-18 if the hypoxic CMC were subjected to the secretome of MSCs.

中文翻译：

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MSC分泌组与MSC共培养对体外缺氧条件下心肌细胞基因表达的比较影响

引言 尽管再生医学取得了重大飞跃，但缺血条件后心肌细胞的再生仍有待阐明。了解缺氧诱导的细胞机制以提供先进的治疗选择至关重要，包括使用干细胞旁分泌因子进行心肌再生。材料与方法 在本研究中，评估缺氧人心肌细胞（Hyp-CMC 组）与人骨髓来源的 MSC（Hyp-CMC-MSC 组）共培养或用 MSC 分泌物刺激时的体外再生潜能。 （组 Hyp-CMC-SMSC）。用细胞因子面板分析常氧 MSC 和 CMC 以及缺氧 CMC 的分泌组。HIF-1α、增殖标志物 Ki-67 和胞质分裂标志物 RhoA 在 4、8、24、48 不同复氧时间段内的基因表达变化，与常氧 CMC 和 MSC 相比，分析了 72 小时和 72 小时。此外，在所有实验装置中评估了促炎细胞因子 IL-18 蛋白表达变化、代谢活性和增殖。结果和结论与 Hyp-CMC 相比，HIF-1α 在 Hyp-CMC-SMSC 中持续过表达（72 小时除外）。在大多数测试时间点，Hyp-CMC-MSC 显示出比 Hyp-CMC-SMSC 更弱的 HIF-1α 表达，除了 8 小时后。在孵育 24 和 48 小时后，Ki-67 表达在 Hyp-CMC 中表现出最强的上调，然后恢复到基线水平，而在 4 和 8 小时和 48 小时，Hyp-CMC-MSC 中的 Ki-67 表达暂时增加在 Hyp-CMC-SMSC 中可以观察到。RhoA 在含氧量正常的 MSC 和 Hyp-CMC-SMSC 中随时间增加，但在 Hyp-CMC-MSC 中没有增加。在 Hyp-CMC-SMSC 和 Hyp-CMC 中检测到 IL-18 蛋白表达的暂时增加。我们的研究表明，根据培养条件的不同，CMCs 的不同缺血和再生相关基因的表达及时动态变化，如果缺氧 CMC 受到 MSCs 分泌组的影响，HIF-1α、RhoA 和 IL-18 的表达更强。