# Piezo1 activation in endothelial cells aggravates microvascular ischemia–reperfusion injury in limbs by enhancing ferroptosis

## TL;DR

The study finds that activating Piezo1 in blood vessel cells worsens tissue damage after blood flow is restored to a limb, suggesting that blocking Piezo1 could help prevent this damage.

## Contribution

The paper reveals a novel role of Piezo1 in promoting microvascular and muscle damage through ferroptosis in limb ischemia-reperfusion injury.

## Key findings

- Piezo1 activation increases microvascular and skeletal muscle damage in limb ischemia-reperfusion injury.
- Pharmacological or genetic inhibition of Piezo1 reduces tissue swelling and infarction.
- Piezo1 promotes ferroptosis via cPLA2 and ACSL4 pathways in endothelial cells.

## Abstract

Acute limb ischemia–reperfusion injury (ALIRI) prominently involves microvascular dysfunction, with notable contributions from damage to microvascular endothelial cells (MECs). Previous research suggests that the mechanosensitive ion channel Piezo1 becomes active in response to mechanical stress conditions, including ischemia and trauma. However, its precise function within the ALIRI context remains elusive. Notably, the expression of Piezo1 was markedly elevated postreperfusion in mouse hind limb ischemia/reperfusion (I/R) models, implicating its crucial involvement in limb survival. Employing specific inhibitors of cell death pathways, the study delineated key molecular drivers of ferroptosis during limb damage. Here evaluations of limb vitality, western blot, quantitative PCR and immunofluorescence implicated that activation of Piezo1 by its agonist exacerbates I/R-induced microvascular perfusion deficits, tissue swelling, skeletal muscle damage and increased tissue infarction and MECs damage. Conversely, these detrimental impacts were mitigated through pharmacological blockade of Piezo1 or specific deletion of Piezo1 in MECs. Comprehensive untargeted metabolomic analysis revealed significant changes primarily in glycerophospholipid and arachidonic acid metabolism pathways. Further experiments demonstrated that RNA interference-mediated inhibition of cytosolic phospholipase A2 (cPLA2) and acyl-CoA synthetase long-chain family member 4 (ACSL4) negated the protective effects against ferroptosis and limb damage that were observed with Piezo1 deletion. Moreover, this study confirmed that protein kinase C phosphorylates ACSL4, which mediates Piezo1-induced ferroptosis and exacerbates limb damage, as shown through immunoprecipitation studies. In summary, Piezo1 contributes to the exacerbation of microvascular and skeletal muscle damage in ALIRI by facilitating the cPLA2-dependent release of arachidonic acid and promoting ACSL4-driven lipid peroxidation, thereby intensifying ferroptosis in MECs.

Acute limb ischemia–reperfusion injury (ALIRI) is a serious condition that can occur after blood flow is restored to a limb. This can cause damage to small blood vessels and tissues. Here researchers wanted to understand how a protein called Piezo1 affects this process. The researchers created a model of ALIRI in mice and observed the effects of Piezo1 on cell death and tissue damage. They found that Piezo1 activation increases calcium levels in cells, which then triggers a series of reactions leading to cell death through a process called ferroptosis. They also discovered that inhibiting Piezo1 reduced tissue damage and cell death. The study concludes that targeting Piezo1 could be a potential strategy to prevent tissue damage in ALIRI. Future research may focus on developing treatments that inhibit Piezo1 to improve outcomes for patients with this condition.

This summary was initially drafted using artificial intelligence, then revised and fact-checked by the author.