Ischemic stroke is an acute cerebrovascular incident marked by an interruption of blood supply to the brain, resulting in dysfunction and eventual neuronal death in the affected areas. Therefore, elucidating the mechanisms of neuronal death following ischemic stroke is imperative for developing novel neuroprotective strategies.

Among these mechanisms is pyroptosis, a direct pathway for ischemic neuronal death, characterized by membrane pore formation alongside inflammatory cytokine leakage. The occurrence and development of pyroptosis hinge on the cleavage and activation of gasdermin D (GSDMD) (Shi et al., 2017). Inflammasomes can directly mediate GSDMD cleavage, serving as important checkpoints in pyroptosis (Wei et al., 2022). The best-characterized inflammasome is the NOD-like receptor family pyrin domain–containing 3 (NLRP3) inflammasome (Zhang et al., 2021a). The NLRP3 inflammasome, a complex of NLRP3, ASC, and caspase-1, can be activated by endogenous danger signals produced by ischemic tissue termed as damage-associated molecular patterns (Hu et al., 2022). We and other researchers have shown that NLRP3 inflammasome-mediated pyroptosis exacerbates neuroinflammation, neuronal death, and neurologic impairment after stroke (Xu et al., 2021; Sun et al., 2020). Thus, targeting pyroptosis may be beneficial in limiting cerebral ischemia/reperfusion (I/R) injury.

Elabela (ELA, Apela, or Toddler peptide), a peptide hormone serving as a novel endogenous ligand for the Apelin receptor (APJ), modulates specific biological processes in multiple tissues (Sharma et al., 2022). The exogenous ELA peptide could alleviate oxidative stress and inflammation of vascular smooth muscle cells in rats with spontaneous hypertension (Ye et al., 2022). In the deoxycorticosterone acetate/salt-induced hypertension model, ELA overexpression inhibited renal reactive oxygen species (ROS) production, thus blocking inflammation and NLRP3 inflammasome activation (Chen et al., 2020a). Furthermore, our previous studies demonstrated a protective role of ELA signaling in ischemic neurons in stroke (Xu et al., 2023; Li et al., 2023a). However, the involvement of ELA in ischemic stroke, particularly concerning neuronal pyroptosis, was not investigated.

One of the hallmarks of I/R injury is the altered structure and function of mitochondria. Excessive mitochondrial fission in experimental stroke exacerbated mitochondrial dysfunction, oxidative stress, neuroinflammation, and neuronal death (Zhou et al., 2021; Zhou et al., 2019; Wu et al., 2017). ELA could ameliorate mitochondrial dysfunction against myocardial ischemic/hypoxic insults (Fu et al., 2020). Nevertheless, the impact of ELA on neuronal mitochondrial fission remains poorly defined.

The present study was conducted to investigate the regulatory role and mechanisms of ELA in neuronal pyroptosis and mitochondrial fission post-ischemic stroke using the mouse middle cerebral artery occlusion (MCAO) model and oxygen–glucose deprivation/reperfusion (OGD/R) in HT-22 hippocampal neurons.