Department of Emergency, the Second Affiliated Hospital of Xi'an Jiaotong University, No. 157 Xiwu Road, Xincheng District, 710004, Xi'an, Shaanxi Province, People's Republic of China.
Inflammation. 2021 Aug;44(4):1565-1580. doi: 10.1007/s10753-021-01441-y. Epub 2021 Mar 16.
The purpose of the present study is to investigate the role of CREB in cardiomyocytes proliferation in regulation of HDAC2-dependent TLR4/NF-κB pathway in severe acute pancreatitis (SAP)-induced myocardial injury. The SAP rat model was developed by injecting sodium touracholate into SD rats and then infected with lentivirus vectors expressing sh-CREB in the presence/absence of LPS. The pathological alterations of rat pancreatic and cardiac tissues were observed by HE staining. TUNEL assay was used to study apoptosis of cardiomyocytes. Next, the loss- and gain-function assay was conducted in LPS-induced myocardial injury cardiomyocytes to define the roles of CREB, HDAC2, and TLR4 in cardiomyocyte proliferation, apoptosis, inflammation, and myocardial injury in vitro. ChIP assay was used to study the enrichment of CREB bound to HDAC2 promoter. RT-qPCR and Western blot analysis were used to detect the expressions of related mRNA and proteins in the NF-κB pathway, respectively. CREB was found to be overexpressed in both SAP tissues and cells. CREB directly bound to the promoter of HDAC2 and activated its expression. Overexpressed CREB or HDAC2 inhibited proliferation and promoted apoptosis of cardiomyocytes. Suppression of CREB inhibited the HDAC2/TLR4/NF-κB cascade to promote proliferation and inhibit apoptosis of cardiomyocytes. The in vitro results were validated in vivo experiments. Coherently, suppression of CREB can inhibit HDAC2/TLR4/NF-κB cascade to promote cardiomyocyte proliferation, thus ameliorating SAP-induced myocardial injury.
本研究旨在探讨 CREB 在调控 HDAC2 依赖性 TLR4/NF-κB 通路在重症急性胰腺炎（SAP）诱导的心肌损伤中心肌细胞增殖中的作用。通过向 SD 大鼠注射牛磺胆酸钠并在 LPS 存在/不存在的情况下感染表达 sh-CREB 的慢病毒载体，建立 SAP 大鼠模型。通过 HE 染色观察大鼠胰腺和心脏组织的病理改变。TUNEL assay 用于研究心肌细胞的凋亡。接下来，在 LPS 诱导的心肌损伤心肌细胞中进行失能和增益功能测定，以确定 CREB、HDAC2 和 TLR4 在体外心肌细胞增殖、凋亡、炎症和心肌损伤中的作用。ChIP assay 用于研究 CREB 与 HDAC2 启动子结合的富集情况。RT-qPCR 和 Western blot 分析分别用于检测 NF-κB 通路中相关 mRNA 和蛋白质的表达。在 SAP 组织和细胞中均发现 CREB 过度表达。CREB 直接与 HDAC2 启动子结合并激活其表达。过表达的 CREB 或 HDAC2 抑制心肌细胞的增殖并促进其凋亡。抑制 CREB 抑制了 HDAC2/TLR4/NF-κB 级联反应，促进了心肌细胞的增殖并抑制了其凋亡。体外结果在体内实验中得到验证。一致地，抑制 CREB 可以抑制 HDAC2/TLR4/NF-κB 级联反应，促进心肌细胞增殖，从而改善 SAP 诱导的心肌损伤。
