前列腺素E1调节急性心肌梗死后内质网应激并提高骨髓间充质干细胞存活率的机制研究

MSCs are considered to be cells of best choice for regeneration of infarct myocardial cells. However, its low survival rate in the ischemic microenvironment after implantation in the infarct area limits their clinical application. prostaglandin E1(PGE1) have been used widely as a vasodilator in clinical practice. Its pharmacological effect includes inhibiting proinflammatory cytokine, promoting revascularization of myocardial scar tissue in ischemic heart diseases, improving myocardial microcirculation after reperfusion injury. Our previous study demonstrated that sustained ischemic microenvironment initiated endoplasmic reticulum stress (ERS) of MSCs, leading to MSCs apoptosis. PGE1 could inhibits significantly serum deprive-induced MSCs apoptosis by stabilizing ERS. PERK/eIF2a signal is the most important and the first activation pathway regulating ERS. It is unclear if PERK/eIF2a is involved in mechanism of PGE1 downregulating ERS and inhiting MSCs apoptosis. We hypothesize that PGE1 inhibits MSCs apoptosis via PERK/eIF2a signaling pathway. In our research plan we use SD-induce MSCs apoptosis models in vitro to mimic the ischemic environment in acute myocardial infarction, using PGE1 and PERK signal block agent Salubrinal to treat MSCs to observe whether PGE1 inhibit MSCs apoptosis via PERK signal. In the In vivo study MSCs are transplanted in the myocardial infarction region together with PGE1 in a rat model. Role of PERK/eIF2a signal in mechanism of PGE1inhibit MSCs apoptosis will be studied by using the color ultrasound echocardiography, MRI and molecular technology. Our study will provide a scientific basis for further improvement of survival rate of transplanted PGE1 in ischemic myocardium after AMI.

骨髓间充质干细胞（MSCs）在治疗急性心肌梗死（AMI）、促进心肌细胞再生具有良好的前景，但MSCs在缺血心肌微环境中大量凋亡致疗效欠佳。内质网应激（ERS）决定细胞凋亡或存活, PERK/eIF2a信号则是调节ERS的重要因素。我们前期研究发现：持续的缺血微环境激发ERS并导致MSCs凋亡；前列腺素E1（PGE1）能下调ERS并抑制MSCs凋亡，但是PGE1抑制MSCs凋亡的详细机制尚不清楚。据此我们提出假说：PGE1通过PERK/eIF2a信号通路，下调ERS表达，最终抑制MSCs的凋亡。本研究拟通过体外建立MSCs缺氧/缺血清模型和大鼠AMI模型，使用PGE1和PERK阻断剂Salubrinal进行干预，从体内外阐明PGE1通过PERK/eIF2a抑制MSCs凋亡的机制。为PGE1调节ERS提高MSCs在AMI后移植存活率提供科学依据。

骨髓间充质干细胞（MSCs）在治疗急性心肌梗死（AMI）具有良好的前景，但MSCs在缺血心肌微环境的大量凋亡是其重要应用瓶颈，确切机制仍未阐明。本研究通过体内外实验应用 PGE1及 PERK阻断剂Salubrinal进行干预 MSCs缺氧/缺血清模型和大鼠 AMI 模型， 通过 检测心肌组织CHOP、GRP78等蛋白表达及 PERK,eIF2a,p-PERK, p-eIF2a，ELISA 检测大鼠血液标本炎症指标的浓度，多普勒超声检查分析心功能的改变， MRI检查MSCs在心肌的存活和分布情况及心梗面积的计算，主要发现如下：（1）证明了缺血心肌的微环境下，PERK/ eIF2a 信号通路被激活，并通过ERS导致MSCs凋亡；（2）PGE1 通过PERK/ eIF2a 的信号通路，抑制ERS 减少MSCs 的凋亡，不仅改善了梗死心肌恶劣的微环境，并增强了MSCs的存活率，改善了心脏功能。综上所述，通过整体及细胞水平的研究证实 PERK/ eIF2a信号通路可以作为有效的治疗靶点，为 PGE1 提高MSCs移植存活率，治疗心肌梗死提供新的理论依据和治疗策略。