抗纤维化短肽N-乙酰基-丝氨酰-天门冬酰-赖氨酰-脯氨酸对大鼠心脏成纤维细胞胶原合成与降解的调节作用

目的探讨N-乙酰基-丝氨酰-天门冬酰-赖氨酰-脯氨酸（AcSDKP）对血小板源性生长因子（PDGF）诱导的大鼠心脏成纤维细胞增殖、胶原合成和降解代谢的调节作用。方法分离培养新生大鼠心脏成纤维细胞。采用^3H-TdR和。H-脯氨酸掺入法分别检测心脏成纤维细胞增殖与胶原蛋白合成。Western blot法检测心脏成纤维细胞Ⅰ、Ⅲ型胶原蛋白表达和基质金属蛋白酶（MMP）-1蛋白的表达。明胶酶谱法检测心脏成纤维细胞MMP-2和MMP-9活性的表达。结果PDGF促进心脏成纤维细胞增殖、胶原合成,Ⅰ、Ⅲ型胶原表达,以及MMP-2、MMP-9活性和MMP-1表达。AcSDKP对PDGF介导的心脏成纤维细胞增殖、胶原合成均有抑制作用。AcSDKP上调由PDGF介导的心脏成纤维细胞MMP-2、MMP-9活性和MMP-1的表达。结论AcSDKP抑制PDGF介导的心脏成纤维细胞增殖和胶原的合成,上调MMPs活性或表达,促进胶原的降解,这些可能与AcSDKP抗心脏纤维化作用相关。     

miR-30a在血管紧张素II诱导的心肌肥厚中的作用

【】目的 研究miR-30a是否介导了血管紧张素II(AngII)诱导的心肌肥厚。方法 用Real-time PCR观察AngII刺激后心肌细胞miR-30a的变化和肥厚基因的表达,用激光共聚焦观察AngII刺激后心肌细胞大小的变化。通过对miR-30a过表达或者抑制miR-30a活性后,观察心肌细胞肥厚基因表达和心肌细胞大小的变化。结果 AngII刺激心肌细胞后,心肌细胞miR-30a表达量下调至刺激前的32.9%。AngII miR-30a mimics组心肌细胞肥厚基因ANP和β-MHC表达分别是negative control组的51.7%和53.5%。AngII miR-30a inhibitors组心肌细胞肥厚基因ANP和β-MHC表达分别是AngII negative control组的1.88倍和1.64倍。激光共聚焦检测形态学的改变,AngII刺激心肌细胞使心肌细胞面积增加至刺激前的2.95倍。与negative control组比较,AngII miR-30a mimics组心肌细胞面积减少至57.8%,AngII miR-30a inhibitors组心肌细胞面积增加至1.50倍。结论miR-30a下调可介导AngII诱导的心肌肥厚。     

lncRNA MIR155HG通过调控miR-133a-3p/Furin轴对心肌成纤维细胞增殖、迁移、分化和胶原合成的影响

目的 探讨长链非编码RNA MIR155宿主基因(lncRNA MIR155HG)对心肌成纤维细胞增殖、迁移、分化和胶原合成的影响及分子机制。方法 构建小鼠心肌梗死模型。分离心肌成纤维细胞,然后分为沉默对照组、沉默MIR155HG组、沉默MIR155HG和抑制物对照组、沉默MIR155HG和干扰miR-133a-3p组、沉默MIR155HG和过表达弗林蛋白(Furin)组。实时荧光定量PCR检测MIR155HG、miR-133a-3p和Furin表达水平;MTT法检测细胞活力;Transwell实验检测细胞迁移;Western blot检测细胞周期蛋白D1(Cyclin D1)、细胞周期蛋白依赖性激酶抑制剂1A(P21)、血管内皮生长因子(VEGF)、Ⅰ型胶原蛋白(Col-1)、α-平滑肌肌动蛋白(α-SMA)表达;荧光素酶报告实验检测MIR155HG和miR-133a-3p以及miR-133a-3p和Furin的靶向关系。结果 在心肌梗死模型小鼠心脏组织中MIR155HG、Furin高表达,miR-133a-3p低表达(P＜0.05)。抑制MIR155HG表达后心肌成纤维细胞的细胞活力、迁移细胞数及Cyclin D1、VEGF、Col-1、α-SMA表达水平显著降低,P21表达水平显著升高(P＜0.05)。MIR155HG靶向调控miR-133a-3p,miR-133a-3p靶向调控Furin。抑制miR-133a-3p表达和过表达Furin逆转了抑制MIR155HG表达对心肌成纤维细胞增殖、迁移、分化和胶原合成相关蛋白的抑制作用。结论 抑制MIR155HG表达可抑制心肌成纤维细胞增殖、迁移、分化和胶原合成,其机制可能与调节miR-133a-3p/Furin轴有关。     

MiR-21-3p在心肌梗死后心肌纤维化中的作用与机制研究

目的 研究miR-21-3p在心肌梗死后心肌纤维化重塑中的作用与机制。方法 选取40只C57雄性小鼠,随机分为正常组、假手术组、心肌梗死+病毒对照组、心肌梗死+miR-21-3p抑制组各10只。利用miR-21-3p mimics转染心肌成纤维细胞,转染48 h以后,利用实时定量PCR及免疫荧光的方法检测mi R-21-3p对心肌成纤维细胞分化以及胶原合成的影响;手术完成4周后行小动物心脏超声、Masson染色以及定量PCR检测各组实验小鼠心功能状态及心肌纤维化程度。利用双荧光素酶实验以及蛋白电泳实验,明确miR-21-3p与磷酸酶和张力蛋白同源物（PTEN）的调控关系。结果 miR-21-3p在心梗组织中显著上调,miR-21-3p表达上调可以显著促进心肌成纤维细胞的增殖、迁移以及分化功能;相较于心肌梗死+病毒对照组,心肌梗死+miR-21-3p抑制组小鼠的左心室射血分数显著改善[（36.12±6.54）%比（18.72±4.23）%,P<0.05],左心室舒张末容积内径显著减少[（3.54±2.13）mm比（5.67±1.42）mm,P<0.05],同时伴有心肌纤维化面...     

微小RNA-155通过靶向缺氧诱导因子1α调控心肌纤维化

目的 探讨微小RNA（miR）-155对心肌成纤维细胞（cardiac fibroblasts, CFs）中纤维化相关基因表达的作用及其机制。 方法 实验分为对照组、血管紧张素(Ang)Ⅱ组、Scramble组、miR-155 mimic组、AngⅡ+ Scramble组、AngⅡ+ miR-155 mimic组、AngⅡ+ HIF-1α siRNA组。AngⅡ刺激原代分离培养的小鼠CFs,模拟心肌纤维化过程中CFs活化过程,采用PCR及Western blot检测各组miR-155、1型胶原（Col 1）、3型胶原（Col 3）、α-平滑肌肌动蛋白（α-SMA）的表达;采用双荧光素酶报告基因实验检测miR-155与缺氧诱导因子（HIF）-1α 3’端非编码区（3’-UTR）的结合作用。 结果 AngⅡ刺激可显著促进小鼠CFs中纤维化相关基因的表达,同时降低miR-155的水平(P <0.05);过表达miR-155可显著降低AngⅡ诱导的小鼠CFs中纤维化相关基因的表达（P <0.05）;HIF-1α受到了miR-155的负性调控,并能同miR-155结合;miR-155 mimic和HIF-1α siRNA能一致性的降低AngⅡ诱导的小鼠CFs中纤维化相关蛋白的表达。 结论 miR-155能抑制AngⅡ诱导的CFs纤维化,进而抑制心肌纤维化;HIF-1α是miR-155的靶基因,并介导了miR-155发挥抑制AngⅡ诱导的CFs纤维化的过程。     

miR-148b参与心肌梗死后心脏纤维化的作用及机制

目的 探讨miR-148b参与大鼠心肌梗死后心脏纤维化的作用及可能机制。方法 采用结扎大鼠冠状动脉左前降支方法制作大鼠心肌梗死模型,RT-PCR法评价大鼠心脏miR-148b表达水平;应用生物信息学方法预测miR-148b靶基因;采用Western blot方法评价大鼠心脏同源性磷酸酶-张力蛋白（phosphatase and tensin homologue,PTEN）及α-平滑肌蛋白（α-smooth muscle actin,α-SMA）蛋白表达水平;四甲基偶氮唑盐比色（MTT）法检测心脏成纤维细胞增殖能力;应用天狼猩红染色评价心脏纤维化病理改变。结果 大鼠心肌梗死组,梗死周边区纤维化程度显著增加,miR-148b表达显著上调（P<0.01）;miR-148b与预测靶基因PTEN mRNA有结合位点;大鼠心肌梗死组,梗死周边区PTEN表达显著下调（P<0.01）;在心脏成纤维细胞中过表达miR-148b,PTEN的蛋白表达水平显著下调（P<0.01）,α-SMA蛋白表达水平显著上调（P<0.01）,细胞增殖能力显著增强（P<0.05）;在AngII诱导心肌纤维化细胞模型中,抑制miR-148b,PTEN蛋白表达水平显著上调（P<0.05）,α-SMA蛋白表达水平显著下调（P<0.01）,心脏成纤维细胞增殖显著减少（P<0.01）。结论 miR-148b通过PTEN参与心肌梗死后心脏纤维化作用。     

血管紧张素II对心脏成纤维细胞Ets-1表达的影响及机制研究

目的 研究血管紧张素II（AngII）对大鼠心脏成纤维细胞(CFs)转录因子Ets-1及其下游促纤维化因子表达和细胞增殖的调节及相关的分子机制。方法 将原代培养的大鼠CFs分为对照组,AngII处理不同时间组以及不同剂量组,采用实时定量RT-PCR及western blotting实验技术检测AngII对Ets-1mRNA及蛋白表达的影响。用AngII受体拮抗剂、MAPKs、PKC及PTK抑制剂预处理CFs,测定其对AngII诱导的Ets-1、结缔组织生长因子(CTGF)、纤溶酶原激活物抑制因子-1(PAI-1)表达及细胞增殖的影响。结果 在CFs中,AngII可呈时间及浓度依赖性诱导Ets-1表达(P<0.05),对其mRNA稳定性则无显著影响。血管紧张素II1型受体(AT1R)拮抗剂losartan、ERK抑制剂PD98059、JNK抑制剂SP600125及PKC抑制剂BIM预处理可显著抑制AngII诱导Ets-1过表达(P<0.05),下调CTGF及PAI-1蛋白表达,抑制AngII诱导的CFs增殖(P<0.05)。结论 AngII通过AT1R及PKC,ERK、JNK信号通路介导诱导CFs Ets-1基因的表达。而且,转录因子Ets-1可能是心肌纤维化过程的一个重要介导因素,其发挥作用的主要途径可能是通过参与调控CFs增殖及促纤维化因子CTGF及PAI-1的表达。     

N-乙酰基-丝氨酰-天门冬酰-赖氨酰-脯氨酸对大鼠心脏成纤维细胞c-Jun氨基末端激酶通路活化的影响

目的 探讨N-乙酰基-丝氨酰-天门冬酰-赖氨酰-脯氨酸(AcSDKP)对血小板源生长因子诱导的大鼠心脏戍纤维细胞增殖及胶原合成以及c-Jun氨基末端激酶表达的影响.方法 选用新生Wistar大鼠心脏成纤维细胞作为实验研究材料,MTT法检测心脏成纤维细胞代谢活性的改变,免疫细胞化学法检测Ⅰ型、Ⅲ型胶原表达的改变,Western Blotting检测大鼠心脏成纤维细胞中磷酸化JNK(p-JNK)和JNK蛋白及Ⅰ型、Ⅲ型胶原蛋白的表达.结果 10μg/L血小板源生长因子刺激下,代表大鼠心脏成纤维细胞代谢活性的OD值增加,Ⅰ型、Ⅲ型胶原表达增强,表明血小板源生长因子刺激了心脏成纤维细胞增殖,促进了胶原的合成.同时p-JNK蛋白表达增高,而JNK蛋白表达无明显改变.10-9mol/L AcSDKP能够抑制血小板源生长因子诱导的大鼠心脏成纤维细胞代谢活性,同时抑制了Ⅰ型、皿型胶原及p-JNK蛋白的表达,而JNK蛋白表达无明显改变.结论 AcSDKP能够通过阻断血小板源生长因子介导的JNK通路激活进而抑制大鼠心脏成纤维细胞增殖和胶原蛋白表达.     

MiR-143促进心脏成纤维细胞增殖

目的寻找调控心脏成纤维细胞增殖的microRNA。方法微矩阵分析比较正常培养和经TGFβ诱导的人成年心脏成纤维细胞microRNA表达谱,发现受TGFβ调控的microRNA。RealtimePCR验证microRNA的表达改变。通过转染模拟物或antagomir,高表达或敲低miR-143表达,MTT实验观察对心脏成纤维细胞增殖的影响。结果 TGFβ诱导心脏成纤维细胞中多个microRNA表达失调。MiR-143表达被TGFβ特异性诱导上调,但不受AngII、CTGF和TNFα的影响。高表达miR-143能够促进心脏成纤维细胞增殖10%左右,而敲低miR-143则显著抑制心脏成纤维细胞增殖。结论 MiR-143在心脏成纤维细胞中受TGFβ信号通路调控,是心脏成纤维细胞增殖的调控因子。     

MiR-197-3p/STAMP2对ox-LDL诱导的人脐静脉内皮细胞凋亡及炎症应激的影响

目的 探究miR-197-3p/前列腺六次跨膜蛋白（Six transmembrane protein of prostate,STAMP）2对氧化型低密度脂蛋白（ox-LDL）诱导的人脐静脉内皮细胞（HUVECs）凋亡和炎症应答。 方法 用ox-LDL处理HUVEC复制内皮细胞损伤模型;RT-PCR检测miR-197-3p和STAMP2表达;ELISA检测细胞凋亡;Western blot用于检测STAMP2,Bax和Bcl-2的蛋白水平;ELISA检测HUVECs中细胞间黏附分子（ICAM）-1,血管内皮细胞黏附分子（VCAM）-1和E选择素（E-selectin）的表达水平;生物信息学预测miR-197-3p的靶基因;并采用双萤光素酶报告系统、qRT-PCR及Western blot验证miR-197-3p与STAMP2的靶向调控关系。 结果 ox-LDL能明显上调miR-197-3p的表达（P<0.05）,同时降低STAMP2的表达（P<0.05）,且呈时间依赖性;下调miR-197-3p能够显著抑制ox-LDL诱导的细胞凋亡（P<0.05）,同时降低促凋亡蛋白Bax并增加抑凋亡蛋白Bcl-2（P<0.05）;抑制miR-197-3p明显降低ox-LDL诱导的炎症因子的表达（P<0.05）;此外,生物信息学预测提示STAMP2是miR-197-3p的靶基因,而且qRT-PCR及Western blot结果显示抑制miR-197-3p明显上调STAMP2 mRNA和蛋白水平（P<0.05）,从而证实miR-197-3p能够靶向调控STAMP2。 结论 MiR-197-3p可以通过靶向调控STAMP2从而调节ox-LDL诱导的HUVECs凋亡及炎症应答,为动脉粥样硬化的靶向治疗提供理论基础。     

MicroRNA-192 in diabetic kidney glomeruli and its function in TGF-beta-induced collagen expression via inhibition of E-box repressors

Key features of diabetic nephropathy (DN) include the accumulation of extracellular matrix proteins such as collagen 1-alpha 1 and -2 (Col1a1 and -2). Transforming growth factor beta1 (TGF-beta), a key regulator of these extracellular matrix genes, is increased in mesangial cells (MC) in DN. By microarray profiling, we noted that TGF-beta increased Col1a2 mRNA in mouse MC (MMC) but also decreased mRNA levels of an E-box repressor, deltaEF1. TGF-beta treatment or short hairpin RNAs targeting deltaEF1 increased enhancer activity of upstream E-box elements in the Col1a2 gene. TGF-beta also decreased the expression of Smad-interacting protein 1 (SIP1), another E-box repressor similar to deltaEF1. Interestingly, we noted that SIP1 is a target of microRNA-192 (miR-192), a key miR highly expressed in the kidney. miR-192 levels also were increased by TGF-beta in MMC. TGF-beta treatment or transfection with miR-192 decreased endogenous SIP1 expression as well as reporter activity of a SIP1 3' UTR-containing luciferase construct in MMC. Conversely, a miR-192 inhibitor enhanced the luciferase activity, confirming SIP1 to be a miR-192 target. Furthermore, miR-192 synergized with deltaEF1 short hairpin RNAs to increase Col1a2 E-box-luc activity. Importantly, the in vivo relevance was noted by the observation that miR-192 levels were enhanced significantly in glomeruli isolated from streptozotocin-injected diabetic mice as well as diabetic db/db mice relative to corresponding nondiabetic controls, in parallel with increased TGF-beta and Col1a2 levels. These results uncover a role for miRs in the kidney and DN in controlling TGF-beta-induced Col1a2 expression by down-regulating E-box repressors.     

Role of miR-21 in the pathogenesis of atrial fibrosis

Atrial fibrosis is important for the pathogenesis of atrial fibrillation (AF) but the underlying signal transduction is incompletely understood. We therefore studied the role of microRNA-21 (miR-21) and its downstream target Sprouty 1 (Spry1) during atrial fibrillation. Left atria (LA) from patients with AF showed a 2.5-fold increased expression of miR-21 compared to matched LA of patients in sinus rhythm. Increased miR-21 expression correlated positively with atrial collagen content and was associated with a reduced protein expression of Spry1 and increased expression of connective tissue growth factor (CTGF), lysyl oxidase and Rac1-GTPase. Neonatal cardiac fibroblasts treated with angiotensin II (AngII) or CTGF showed an increased miR-21 and decreased Spry1 expression. Pretreatment with an inhibitor of Rac1 GTPase, NSC23766, reduced the AngII-induced upregulation of miR-21. A small molecule inhibitor of lysyl oxidase, BAPN, prevented the AngII as well as the CTGF-induced miR-21 expression. Transgenic mice with cardiac overexpression of Rac1, which develop spontaneous AF and atrial fibrosis with increasing age, showed upregulation of miR-21 expression associated with reduced Spry1 expression. miR-21 expression and signalling in vivo were prevented by long-term treatment of the mice with statins. Direct inhibition of miR-21 by antagomir-21 prevented fibrosis of the atrial myocardium post-myocardial infarction. Left atria of patients with atrial fibrillation are characterized by upregulation of miR-21 und reduced expression of Spry1. Activation of Rac1 by angiotensin II leads to a CTGF- and lysyl oxidase-mediated increase of miR-21 expression contributing to structural remodelling of the atrial myocardium.     

Direct effects of high glucose and insulin on protein synthesis in cultured cardiac myocytes and DNA and collagen synthesis in cardiac fibroblasts

The present study examined the direct effects of high glucose and insulin on protein synthesis in cardiac myocytes and DNA and collagen synthesis in cardiac fibroblasts. Cultured rat cardiac myocytes and fibroblasts were grown in media containing normal glucose, high glucose, or osmotic control, and incubated with or without insulin. In cardiac myocytes, high glucose had no effect, but insulin increased protein synthesis and atrial natriuretic peptide (ANP) secretion and gene expression. The extracellular signal-regulated protein kinase (ERK)/mitogen-activated protein kinase (MAPK) inhibitor and the protein kinase C (PKC) inhibitor blocked insulin-induced protein synthesis. In cardiac fibroblasts, high glucose and osmotic control media increased DNA synthesis. Collagen synthesis and fibronectin and transforming growth factor-beta1 (TGF-beta1) mRNA expression were stimulated by high glucose, but not by osmotic control. Insulin increased DNA and collagen synthesis in fibroblasts, and the insulin-induced increase in DNA synthesis was blocked by the phosphatidylinositol 3 kinase (PI3K) inhibitor. Our findings suggest that cardiomyocyte protein synthesis is mainly regulated by insulin rather than high glucose and both high glucose and insulin contribute to fibroblast DNA and collagen synthesis. High glucose accelerates fibroblast DNA synthesis and collagen synthesis, and fibronectin and TGF-beta1 mRNA expression, dependent or independent of osmotic stress. Insulin regulates myocyte protein synthesis and fibroblast DNA synthesis through different intracellular mechanisms.     

重组人松弛素体外调节血管紧张素Ⅱ诱导的大鼠心肌纤维化

目的:观察在重组人松弛素(rhRLX)及血管紧张素Ⅱ(AngⅡ)作用下对心脏成纤维细胞功能(CFs)的影响。方法:原代培养Sprague-Dawley大鼠心脏成纤维细胞,经AngⅡ(10-6mmol/L)单独作用及AngⅡ加rhRLX(100μg/L)共同作用后,用MTT比色法测定CFs的增殖;用ELISA法检测Ⅰ型前胶原羧基末端肽(PⅠCP)和Ⅲ型前胶原氨基末端肽(PⅢNP)的水平。结果:rhRLX可显著抑制AngⅡ促进CFs增殖,并拮抗AngⅡ促进CFs分泌PⅠCP的作用。结论:rhRLX能够改善AngⅡ诱导的心肌纤维化。     

Angiotensin II AT(1)-receptor induces biglycan in neonatal cardiac fibroblasts via autocrine release of TGFbeta in vitro

OBJECTIVE: After myocardial infarction, angiotensin II (AngII) promotes ventricular remodeling and deposition of extracellular matrix (ECM), e.g., collagen type 1 and 3. Whether AngII regulates the expression of small leucine-rich proteoglycans (SLRP) which are important modulators of collagen fibrillogenesis and are induced after experimental myocardial infarction in rats is not known. The aim of the present study was therefore to analyse in cultured cardiac fibroblasts the expression and secretion of the SLRP biglycan in response to AngII. METHODS: Cardiac fibroblasts were isolated from neonatal Wistar Kyoto rats and used in the first passage. Expression of AT(1)- and AT(2)-receptors was verified by RT-PCR. Expression of protoeglycans was analyzed after metabolic labeling with [35S]-sulfate, by SDS-PAGE and Western analysis. In addition, mRNA expression was examined by means of RT-PCR and Northern analysis. The activity of the biglycan promoter was analyzed using three biglycan promoter-luciferase fusion constructs. RESULTS: Biglycan was found to be the predominant proteoglycan produced by neonatal cardiac fibroblasts in vitro. In response to AngII (10(-7) M), secretion of total [35S]-labeled proteoglycans and mRNA of biglycan were increased to 116+/-1.8% and 121+/-11% (n=5, mean+/-S.E.M.) of unstimulated controls, respectively. Biglycan induction in response to AngII was sensitive to Losartan (10(-5) M) and unaffected by PD123177 (10(-6) M), suggesting that the AT(1)-receptor mediates the induction of biglycan. Direct activation of the biglycan promoter downstream of the AT(1)-receptor was excluded by promoter activity assays. Instead, increased release of transforming growth factor beta 1 (TGFbeta1) was detected by ELISA in response to AT(1)-receptor stimulation. Furthermore, neutralising antibodies to TGFbeta1 inhibited biglycan induction in response to AngII. CONCLUSION: The results indicate that in cardiac fibroblasts AngII via the AT(1)-receptor causes autocrine release of TGFbeta1, which in turn induces biglycan expression and secretion.     

Notch3 Ameliorates Cardiac Fibrosis After Myocardial Infarction by Inhibiting the TGF-β1/Smad3 Pathway

Notch3 and TGF-β1 signaling play a key role in the pathogenesis and progression of chronic cardiovascular disease. However, whether Notch3 protects against myocardial infarction (MI) and the underlying mechanisms remains unknown. C57BL/6 mice were randomized to be treated with Notch3 siRNA (siNotch3) or lentivirus carrying Notch3 cDNA (Notch3) before coronary artery ligation. Four weeks after constructing MI model, cardiac function and fibrosis were compared between groups. The cardiac fibroblast cells (CFs) were isolated from newborn C57BL/6 mice (1–3 days old) and transfected with lentivirus carrying Notch3 cDNA. TGF-β1 (5 ng/ml), a well-known pro-fibrotic factor, was administered 72 h after Notch3 cDNA administration in CFs. The related proteins of fibrosis such as a-smooth muscle actin (a-SMA), Type I collagen, metalloprotease (MMP)-9 and the tissue inhibitor of metalloproteinases (TIMP)-2 were examined by western blot analysis. Notch3 cDNA treatment attenuated cardiac damage and inhibited fibrosis in mice with MI. Meanwhile, Notch3 siRNA administration aggravated cardiac function damage and markedly enhanced cardiac fibrosis in mice with MI. Overexpression of Notch3 inhibited TGF-β1-induced fibroblast–myofibroblast transition of mouse cardiac fibroblast cells, as evidenced by down-regulating a-SMA and Type I collagen expression. Notch3 cDNA treatment also increased MMP-9 expression and decreased TIMP-2 expression in the TGF-β1-stimulated cells. This study indicates that Notch3 is an important protective factor for cardiac fibrosis in a MI model, and the protective effect of Notch3 is attributable to its action on TGF-β1/Smad3 signaling.     

微小RNA-370在心肌梗死后纤维化中的作用

目的:本实验研究了心肌梗死后梗死交界部位微核糖核酸-370(miR-370)的表达情况以及其在梗死后纤维化过程中的作用。方法:建立SD大鼠心肌梗死模型,2w后RT-PCR法、Western blotting法检测心肌梗死交界区TGFβ1、TGFβRⅡ、ColⅠα1、ColⅢα1 mRNA和miR-370的表达情况以及TGFβ1、TGFβRⅡ、α-SMA蛋白的表达。分离、培养SD大鼠乳鼠心肌成纤维细胞,AngⅡ、miR-370干预细胞后检测上述指标的变化。荧光素酶报告实验验证TGFβRⅡ是否为miR-370的靶基因。结果:心肌梗死后梗死交界区miR-370的表达下降而TGFβ1、TGFβRⅡ、ColⅠα1、ColⅢα1 mRNA表达以及TGFβ1、TGFβRⅡ、α-SMA蛋白的表达均增加。荧光素酶报告实验证实TGFβRⅡ是miR-370的靶基因。miR-370能够通过降低TGFβRⅡ的表达,抑制AngⅡ导致的TGFβRⅡ以及胶原蛋白表达升高以及肌成纤维细胞的分化效应但是并不能抑制TGFβ1表达。结论:miR-370能够通过与TGFβRⅡmRNA结合,抑制TGFβRⅡ蛋白的表达部分阻断了TGFβ1-TGFβRⅡ及下游信号转导通路发挥抗纤维化效应。