ACSL4 contributes to ferroptosis‐mediated rhabdomyolysis in exertional heat stroke

Abstract

Background Rhabdomyolysis (RM) is a common complication of exertional heat stroke (EHS) and constitutes a direct cause of death. However, the mechanism underlying RM following EHS remains unclear. Methods The murine EHS model was prepared by our previous protocol. RNA sequencing is applied to identify the pathological pathways that contribute to RM following EHS. Inhibition of the acyl‐CoA synthetase long‐chain family member 4 (ACSL4) was achieved by RNA silencing in vitro prior to ionomycin plus heat stress exposure or pharmacological inhibitors in vivo prior to heat and exertion exposure. The histological changes, the iron accumulation, oxidized phosphatidylethanolamines species, as well as histological evaluation and levels of lipid metabolites in skeletal muscle tissues were measured. Results We demonstrated that ferroptosis contributes to RM development following EHS. Ferroptosis inhibitor ferrostatin‐1 administration once EHS onset significantly ameliorated the survival rate of EHS mice from 35.357% to 52.288% within 24 h after EHS (P = 0.0028 compared with control) and markedly inhibited RM development induced by EHS. By comparing gene expression of between sham heat rest (SHR) (n = 3) and EHS (n = 3) mice in the gastrocnemius (Gas) muscle tissue, we identified that Acsl4 mRNA expression is elevated in Gas muscle tissue of EHS mice (P = 0.0038 compared with SHR), so as to its protein levels (P = 0.0001 compared with SHR). Followed by increase in creatine kinase (CK) and myoglobin (MB) levels, the labile iron accumulation, decrease in glutathione peroxidase 4 (GPX4) expression, and elevation of lipid peroxidation products. From in vivo and in vitro experiments, inhibition of Acsl4 significantly improves muscle cell death caused by EHS, thereby ameliorating RM development, followed by reduction in CK and MB levels by 30–40% (P < 0.0001; n = 8–10) and 40% (P < 0.0001; n = 8–10), restoration of GPX4 expression, and decrease in lipid peroxidation products. Mechanistically, ACSL4‐mediated RM seems to be Yes‐associated protein (YAP) dependent via TEA domain transcription factor1/TEA domain transcription factor4. Conclusions These findings demonstrate an important role of ACSL4 in mediating ferroptosis activation in the development of RM following EHS and suggest that targeting ACSL4 may represent a novel therapeutic strategy to limit the skeletal muscle cell death and prevent RM after EHS.

The molecular and metabolic landscape of iron and ferroptosis in cardiovascular disease

“…The enzyme long-chain fatty acid CoA ligase 4 (LACS4) converts PUFAs to the acylated form and is considered to be a specific driver of ferroptosis, as its upregulation increases PUFA content in phospholipids and renders the cell more susceptible to ferroptosis 144 , 145 . Although an in-depth study into the role of LACS4 in cardiac muscle has not yet been conducted, this enzyme has been shown to be a novel therapeutic target for limiting skeletal muscle cell death and preventing rhabdomyolysis 146 .…”

Myostatin/HIF2α-Mediated Ferroptosis is Involved in Skeletal Muscle Dysfunction in Chronic Obstructive Pulmonary Disease

“… 26 Another study with a sarcopenic mouse model suggested that iron overload upregulated p53 expression, thereby inhibiting the expression of SLC7A11, and ultimately leading to ferroptosis through LPO accumulation in skeletal muscle cells. 16 Ferroptosis has also been found to be involved in rhabdomyolysis caused by exertional heat stroke 27 and in atorvastatin-induced myopathy. 28 In our study, mRNA sequencing performed on skeletal muscles showed that the ferroptosis pathway was markedly enriched in COPD, accompanied by abnormal expression of Gpx4 and Ncoa4 .…”

Ferroptosis and musculoskeletal diseases: “Iron Maiden” cell death may be a promising therapeutic target

“…In animal models, iron chelators also have the ability to protect functional and histologic RM ( 132 ). Another previous study indicated the protective role of ACSL4 in mediating ferroptosis in the development of RM following EHS, which suggests that ACSL4 may also be a novel therapeutic target in RM ( 133 ). Overall, we point out that ferroptosis may play a vital role as a fundamental mechanism in a variety of MSKs ( Figure 6 ).…”