ACE-inhibition induces a cardioprotective transcriptional response in the metabolic syndrome heart.

The goal of the current study was to characterize the cardiac transcriptional signature of the metabolic syndrome (MetS) murine model relative to the healthy, control heart and the differential changes induced by ACE-inhibition, a frequent intervention in MetS subjects, at the transcriptomic level in control and MetS hearts. Methods - LDLR-/-;ob/ob (DKO, MetS model) and C57Bl6/J (WT) mice were injected with ACE-inhibitor captopril (10 mg/kg/day) between 12 and 24 weeks of age, or NaCl 0,9% as controls. Transcriptome analysis (RNA-seq) from the whole heart RNA samples was performed. Differential gene expression was analysed with Cufdiff. Ingenuity Pathway Analysis (IPA) was used to determine functional enrichment, and analyse pathways, networks, and upstream regulators. Transcription factor motif enrichment analysis was performed with i-cisTarget. Results – 288 genes implicating 72 pathways were differentially expressed between DKO and WT hearts. The hallmarks of MetS in the heart were an increase in activity of the following pathways: ILK, Rho, dendritic cell maturation, production of nitric oxide and reactive oxygen species in macrophages, atherosclerosis, LXR-RXR, cardiac hypertrophy, and acute phase response. ACE-inhibition resulted in a limited transcriptional effect in WT hearts and in a decrease in activity of Rho-associated signalling pathways. In contrast, a more prominent transcriptional effect was observed in DKO hearts. Similar to WT, Rho-associated pathways were affected, but ACE-inhibition further displayed a counteracting effect on the pathways affected by MetS in the heart Conclusion –MetS and control mouse hearts have unique transcriptional profiles, with characteristic baseline gene expression landscapes prior to ACE-inhibition, and a partially specific transcriptional response to ACE-inhibition. The Rho-associated signalling pathways and Rho, Rock, Myl, and Fos genes represent potential therapeutic targets. Overall design: Experimental animal models: DKO; LDLR-/- and ob/ob)18. C57BL/6 (WT); RNA Extraction and Sequencing; RNA-Seq Data Analysis; Pathway and Regulatory Network Analysis; Ethical committee approval.本研究旨在从转录组层面，对比健康对照心脏与代谢综合征（Metabolic Syndrome, MetS）小鼠模型的心脏转录特征，并解析血管紧张素转换酶（Angiotensin-Converting Enzyme, ACE）抑制疗法——代谢综合征患者常用临床干预手段——对对照与MetS小鼠心脏所诱导的差异转录变化。 实验方法：选用LDLR受体敲除/瘦素纯合缺失（DKO，MetS模型）与C57BL/6J（野生型WT）小鼠，于12至24周龄期间每日腹腔注射ACE抑制剂卡托普利（10 mg/kg/天），对照组注射0.9%氯化钠溶液。提取全心脏RNA样本进行转录组测序（RNA Sequencing, RNA-seq）分析；采用Cufdiff进行差异基因表达分析；通过Ingenuity通路分析（Ingenuity Pathway Analysis, IPA）开展功能富集注释，对通路、调控网络及上游调控因子进行解析；利用i-cisTarget完成转录因子基序富集分析。 结果：结果显示，DKO与WT小鼠心脏间共存在288个差异表达基因，涉及72条信号通路。小鼠心脏中代谢综合征的特征性分子改变为以下通路活性上调：整合素连接激酶（Integrin-Linked Kinase, ILK）通路、Rho信号通路、树突状细胞成熟通路、巨噬细胞一氧化氮与活性氧生成通路、动脉粥样硬化通路、LXR-RXR通路、心肌肥厚通路以及急性期反应通路。ACE抑制疗法对WT小鼠心脏的转录调控影响有限，仅可下调Rho相关信号通路的活性。与之相反，该疗法对DKO小鼠心脏的转录调控作用更为显著：除同样影响Rho相关通路外，还可抵消代谢综合征在心脏中诱导的通路异常激活。 结论：综上，代谢综合征与对照小鼠心脏具有独特的转录表达谱，在ACE抑制疗法实施前即存在特征性的基础基因表达特征，且对ACE抑制疗法呈现部分特异性的转录应答。Rho相关信号通路以及Rho、Rock、Myl与Fos基因可作为潜在治疗靶点。 整体实验设计：实验动物模型：DKO（LDLR-/-与ob/ob双敲）18、C57BL/6（WT）；RNA提取与测序；RNA-seq数据分析；通路与调控网络分析；伦理委员会审批。