Fam117b调控cAMP信号通路促进病理性心肌肥厚的作用机制

Fam117b Regulating cAMP Signaling Pathway to Promote Pathological Myocardial Hypertrophy

目的:通过加权基因共表达网络分析(WGCNA)对小鼠心脏转录组测序数据进行分析,筛选与心肌肥厚发生有关的基因和细胞信号通路。方法:通过主动脉弓缩窄法(TAC)构建心肌肥厚小鼠模型,在体外水平、解剖水平和病理水平对模型进行评价。对小鼠心肌组织进行转录组测序,筛选表达差异的基因。利用基因集富集分析(GSEA)和WGCNA筛选与心肌肥厚发生相关的蛋白和细胞信号通路。结果:模型建立4周后,小鼠心脏的结构和功能发生明显改变,主要表现在小鼠左室后壁舒张末期厚度(LVPWd)较对照小鼠明显增加(P<0.05),而左室射血分数(LVEF)和左室短轴缩短率(LVFS)较对照组明显降低(P<0.05)。模型组心体比和心胫比均较对照组明显增加(P<0.05)。心肌组织麦胚凝集素/凝集蛋白(WGA)染色结果显示,模型组小鼠心肌细胞麦胚凝集素/凝集蛋白染色定量较对照组小鼠明显增大(P<0.05)。小鼠心肌组织转录组测序结果显示,与对照组比较,模型组心肌组织中分别有451个基因明显上调,225个基因明显下调。对差异基因进行GSEA分析,环磷酸腺苷(cAMP)信号通路被明显富集,且其在模型组小鼠心肌组织中被明显上调。小鼠心肌转录组测序数据WGCNA分析结果显示,由385个基因构成的共表达网络与心肌肥厚的表型相关,其中包括19个明显上调基因和32个明显下调基因。对共表达网络进行基因本体(GO)分析,富集得到多条与心肌肥厚发生密切相关的生物过程,如蛋白代谢及磷酸化、器官发育、细胞凋亡等。进一步相关分析发现,共表达网络中的基因Fam117b在心肌肥厚小鼠心脏中的表达与cAMP信号通路中的基因表达呈正相关,且其在模型组小鼠心肌组织中表达被明显上调。结论:Fam117b能够通过激活cAMP信号通路诱导病理性心肌肥厚的发生,这将为该病的临床治疗提供新的靶点。

Objective:Mouse heart transcriptome sequencing data were analyzed by weighted gene coexpression network analysis(WGCNA)to screen genes and cell signaling pathways related to the occurrence with myocardial hypertrophy.Methods:A mouse model of myocardial hypertrophy was constructed by transverse aortic constriction(TAC)and evaluated at the in vitro,anatomical and pathological levels.Transcriptome sequencing was performed on mouse myocardial tissue to screen the genes with different expression.Gene set enrichment analysis(GSEA)and WGCNA were used to screen proteins and cell signaling pathways associated with myocardial hypertrophy.Results:Four weeks after the establishment of the model,the structure and function of the mouse heart were significantly changed,mainly in the end diastolic thickness(LVPWd)of the left ventricular posterior wall significantly increased compared with that of the control mice(P<0.05),while the left ventricular ejection fraction(LVEF)and left ventricular short axis shortening rate(LVFS)significantly decreased compared with that of the control group(P<0.05).The heart-to-body ratio in model group and tibia ratio in control group significantly increased(P<0.05).The results of wheat germ lectin/agglutinin(WGA)staining showed that the area of myocardial cells in the model group was significantly increased compared with that in the control group(P<0.05).Transcriptome sequencing of mouse myocardial tissue showed that 451 and 225 genes were significantly up-regulated or down-regulated in the myocardial tissue of the model group compared with that of the control group.By GSEA analysis of differential genes,cyclic adenosine phosphate(cAMP)signaling pathway obviously enriched,and it was significantly upregulated in myocardial tissue of model group mice.The results of WGCNA analysis of mouse myocardial transcriptome sequencing data showed that the co-expression network composed of 385 genes associated with the phenotype of myocardial hypertrophy,including 19 significantly up-regulated genes and 32 significantly down-regulated genes.Through gene ontology(GO)analysis of co-expression network,multiple biological processes closely related to myocardial hypertrophy were obtained,such as protein metabolism and phosphorylation,organ development,cell apoptosis,etc.Further correlation analysis showed that the expression of the gene Fam117b in the co-expression network was positively correlated with the gene expression in the cAMP signaling pathway in the heart of mice with myocardial hypertrophy,and its expression was significantly up-regulated in the myocardial tissue of mice in the model group.Conclusion:Fam117b can induce pathological myocardial hypertrophy by activating cAMP signaling pathway,which will provide a new target for clinical treatment of this disease.