[Estradiol-ERβ signaling axis promotes myofiber repair in female mice with acute skeletal muscle inflammation by regulating IGF-1 expression from M2 macrophages].

Authors

Zhaohong Liao, Shuzhen Zhang, Nan Wang, Xiaolu Niu, Jingxia Lu, Yuanqi Sun, Yueming Chen, Chen Li, Jixia Li

Published in

Zhong nan da xue xue bao. Yi xue ban = Journal of Central South University. Medical sciences. Volume 51. Issue 6. Pages 1192-1205. Jun 28, 2026.

Abstract

Estradiol is the principal form of estrogen, and its role in tissue injury and repair varies according to the regenerative capacity of the tissue. However, its mechanism of action in skeletal muscle, which has a strong regenerative capacity, remains unclear. This study aims to investigate the effects of estradiol signaling on myofiber regeneration and repair in a mouse model of cardiotoxin (CTX)-induced acute skeletal muscle inflammation.
In vivo experiments: A total of 80 wild-type male and 205 wild-type female C57BL/6 mice were included, of which 75 female mice underwent ovariectomy (OVX). Following the induction of acute skeletal muscle inflammation with CTX, the mice received intramuscular injections of β-estradiol, 4-[2-phenyl-5,7-bis(trifluoromethyl)pyrazolo[1,5-a]pyrimidin-3-yl]phenol (PHTPP), or other agents. The mice were divided into a control group, a β-estradiol group, a PHTPP group, a OVX group, and an OVX+β-estradiol group. Serum estradiol and creatine kinase (CK) levels were measured using enzyme-linked immunosorbent assays (ELISA). Real-time reverse transcription polymerase chain reaction (real-time RT-PCR) was used to determine the messenger RNA (mRNA) expression of monocyte chemoattractant protein-1 (MCP-1) and interleukin (IL)-13 in injured muscle from female mice. The expression of estrogen receptor (ER)α, ERβ, G protein-coupled estrogen receptor (GPR) 30, in injured muscle was assessed using real-time RT-PCR and Western blotting (WB). Flow cytometry was used to determine macrophage phenotypes and the proportions of M2 macrophages expressing insulin-like growth factor-1 (IGF-1) or hepatocyte growth factor (HGF) in injured muscle from female mice. Immunofluorescence staining was performed to evaluate monocyte/macrophage infiltration and the expression of phosphorylated IGF-1 receptor (p-IGF-1R) and embryonic myosin heavy chain (eMHC). In vitro experiments: C2C12 mouse myoblasts were differentiated into mature myotubes in medium containing 2% horse serum (HS) for 72 hours and then treated with interferon gamma (IFN-γ), β-estradiol, PHTPP, or combinations of these agents for 24 hours. Both monoculture and coculture systems were established. In the monoculture system, the main groups were control (C2C12+HS), IFN-γ, IFN-γ+β-estradiol, IFN-γ+PHTPP, and IFN-γ+β- estradiol+PHTPP. WB was used to assess the expression of mesenchymal-epithelial transition factor (c-Met), p-IGF-1R, paired box protein 7 (Pax7), and other proteins in C2C12 cells. In the coculture system, after 24 hours of treatment with IFN-γ, β-estradiol, PHTPP, or their combinations, C2C12 cells were cocultured with mouse peritoneal macrophages for 4 hours. The main groups were control (C2C12+HS+macrophages), IFN-γ, IFN-γ+β-estradiol, IFN-γ+PHTPP, and IFN-γ+β- estradiol+PHTPP. Flow cytometry was used to determine macrophage phenotypes and the proportions of M2 macrophages expressing HGF or IGF-1. WB was used to assess c-Met, p-IGF-1R, and Pax7 protein expression in C2C12 cells in the coculture system.
Vivo experiments showed that serum estradiol levels and ERβ expression in injured muscle were significantly higher in female mice than in male mice (both P<0.05). Compared with the control group, the OVX group showed significant decreases in the proportion of IGF-1-expressing M2 macrophages in injured muscle, the expression of eMHC and p-IGF-1R, and the mRNA expression of IL-13 (all P<0.05). In the in vitro experiments, no significant between-group differences were observed in c-Met, p-IGF-1R, or Pax7 protein expression in C2C12 cells in the monoculture system (all P>0.05). In the coculture system, compared with the IFN-γ group, the proportion of M2-type Mac expressing IGF-1 in the IFN-γ+β-estradiol group was significantly upregulated in both p-IGF-1R and Pax7 of C2C12 cells (all P<0.05), while in the IFN-γ+PHTPP group, the trend was opposite (all P<0.05).
Estradiol-ERβ signaling axis promotes the infiltration of M2 macrophages into injured skeletal muscle and enhances their expression of IGF-1 in female mice, thereby alleviating inflammation and promoting myofiber regeneration and repair.

PMID:
42702381
Bibliographic data and abstract were imported from PubMed on 07 Sep 2026.

Read full publication at:
Please sign in to see all details.

Stats

1-terrible, 9-excellent. How would you rate this publication? Sign in in to submit your rating.

Post a comment

You need to be signed in to post comments. You can sign in here.

Comments

There are no comments yet.