A cardiac fibroblast-enriched micropeptide regulates inflammation in ischemia/reperfusion injury
Youchen Yan, Tingting Zhang, Xin He, Tailai Du, Gang Dai, Xingfeng Xu, Zhuohui Chen, Jialing Wu, Huimin Zhou, Yazhi Peng, Yan Li, Chen Liu, Xinxue Liao, Yugang Dong, Jing-song Ou, Zhan-Peng Huang
Youchen Yan, Tingting Zhang, Xin He, Tailai Du, Gang Dai, Xingfeng Xu, Zhuohui Chen, Jialing Wu, Huimin Zhou, Yazhi Peng, Yan Li, Chen Liu, Xinxue Liao, Yugang Dong, Jing-song Ou, Zhan-Peng Huang
View: Text | PDF
Research Article Cardiology Cell biology

A cardiac fibroblast-enriched micropeptide regulates inflammation in ischemia/reperfusion injury

Abstract

Inflammation is a critical pathological process in myocardial infarction. Although immunosuppressive therapies can mitigate inflammatory responses and improve outcomes in myocardial infarction, they also increase the risk of infections. Identifying novel regulators of local cardiac inflammation could provide safer therapeutic targets for myocardial ischemia/reperfusion injury. In this study, we identified a previously uncharacterized micropeptide, which we named Inflammation Associated MicroPeptide (IAMP). IAMP is predominantly expressed in cardiac fibroblasts, and its expression is closely associated with cardiac inflammation. Downregulation of IAMP promotes, whereas its overexpression prevents, the transformation of cardiac fibroblasts into a more inflammatory phenotype under stressed/stimulated conditions, as evidenced by changes in the expression and secretion of proinflammatory cytokines. Consequently, loss of IAMP function leads to uncontrolled inflammation and worsens cardiac injury following ischemia/reperfusion surgery. Mechanistically, IAMP promotes the degradation of HIF-1α by interacting with its stabilizing partner HSP90 and, thus, suppresses the transcription of proinflammatory genes downstream of HIF-1α. This study underscores the significance of fibroblast-mediated inflammation in cardiac ischemia/reperfusion injury and highlights the therapeutic potential of targeting micropeptides for myocardial infarction.

Authors

Youchen Yan, Tingting Zhang, Xin He, Tailai Du, Gang Dai, Xingfeng Xu, Zhuohui Chen, Jialing Wu, Huimin Zhou, Yazhi Peng, Yan Li, Chen Liu, Xinxue Liao, Yugang Dong, Jing-song Ou, Zhan-Peng Huang

×

Figure 7

IAMP destabilizes HIF-1α proteins through interacting with HSP90.

Options: View larger image (or click on image) Download as PowerPoint
IAMP destabilizes HIF-1α proteins through interacting with HSP90. (A–C) ...
(A–C) HIF-1α stability in cardiac fibroblasts transfected with IAMP siRNAs (A), isolated from IAMP-KO and Ctrl mice (B), or infected by Ad-FLAG-IAMP (C) were exposed to NiCl2 (50 mM) for 24 hours. Cells were cultured with cycloheximide (CHX) (50 μg/mL) with indicated time before harvest. Western blotting and quantification of HIF-1α were shown. n = 3–4 for each group. (D and E) Coimmunoprecipitation and Western blotting showing the interaction of exogenous HA-HSP90 and FLAG-IAMP (D) and endogenous HSP90 and exogenous FLAG-IAMP in HEK293 cells (E). (F) Coimmunoprecipitation and Western blotting showing the interaction of endogenous HSP90 and exogenous FLAG-IAMP in cardiac fibroblasts. (G) Coimmunoprecipitation and Western blotting showing the interaction of endogenous HSP90 and IAMP in cardiac fibroblasts isolated from IAMP-KO or Ctrl mice. (H) Western blotting and quantification of HIF-1α protein in HEK293 transfected with indicated plasmids for 12, 24, and 48 hours. n = 4 for each group. (I) Western blotting and quantification of HIF-1α protein in HEK293 transfected with indicated plasmids. n = 3 for each group. (J and K) Pull-down experiments with anti-HSP90 antibodies followed by Western blotting detecting the interaction of HSP90 and HIF-1α in control and IAMP-KD cardiac fibroblasts (n = 3 for each group) (J), and in myocardium from Ctrl and IAMP-KO mice 6 hours after I/R surgery (n = 4 for each group) (K). (L and M) Gene expression of Il6, S100a8, and Mmp3 in cardiac fibroblasts (L) and IL-6 protein (M) in the culture medium of cardiac fibroblasts transfected with IAMP or control siRNAs with or without treatment with 17-AAG. n = 3 for each group. *P < 0.05; **P < 0.01; ***P < 0.001; ****P < 0.0001, by 2-tailed Student’s t test (A–C, H, J, and K) or ANOVA with Tukey’s correction (I, L, and M).