Enriched Environment Attenuates Ferroptosis after Cerebral Ischemia/Reperfusion Injury via the HIF-1α-ACSL4 Pathway

Abstract

Enriched environment (EE) has been proven to be an effective intervention strategy which can improve neurofunctional recovery following cerebral ischemia/reperfusion (I/R) injury. However, it still needs further investigation for the underlying mechanisms. Recently, it has been shown that ferroptosis played an essential role in the pathophysiological development of ischemic stroke (IS). This study is aimed at investigating whether EE plays a neuroprotective role by attenuating ferroptosis after cerebral I/R injury. We used middle cerebral artery occlusion/reperfusion (MCAO/R) to build a model of cerebral I/R injury. To evaluate the effect of EE on neurological recovery, we used the modified neurological severity score (mNSS) and the Morris water maze (MWM). We used the western blot to detect the protein levels of glutathione peroxidase 4 (GPX4), hypoxia-inducible factor-1α (HIF-1α), and acyl-CoA synthetase long-chain family member 4 (ACSL4). We used the quantitative real-time PCR (qRT-PCR) to measure the mRNA levels of ACSL4 and inflammatory cytokines including tumor necrosis factor alpha (TNFα), interleukin-6 (IL-6), and interleukin 1 beta (IL-1β). The occurrence of ferroptosis was detected by TdT-mediated dUTP nick-end labeling (TUNEL) assay, diaminobenzidine- (DAB-) enhanced Perls’ staining, iron level assays, and malondialdehyde (MDA) level assays. The results verified that EE enhanced functional recovery and attenuated ferroptosis and neuroinflammation after cerebral I/R injury. EE increased the expression of HIF-1α while inhibited the expression of ACSL4. Our research indicated that EE improved functional recovery after cerebral I/R injury through attenuating ferroptosis, and this might be related to its regulation of the neuroinflammation and HIF-1α-ACSL4 pathway.

Progress of Ferroptosis in Ischemic Stroke and Therapeutic Targets

“…The increase of HIF-1α protein was also observed in mice and primate brains after experimental cerebral ischemia (Speer et al 2013 ), which might account for the early neuroprotective role of HIF-1α (Cui et al 2021 ). As shown in a recent study, enriched environment (EE) promoted HIF-1α expression and thus inhibited ACSL4 expression at the transcriptional level, ultimately acting to inhibit ferroptosis in MCAO/R rats (Liu et al 2023b ).…”

“…It was demonstrated that PIO could decrease infarct volume and improve the neurological score of transient MCAO mice (Jin et al 2021 ). Reduction in infarct volume and inflammation as well as improvement in neurological function were observed during the treatment with PIO of rats before or after MCAO (Liu et al 2023b ). As a synthetic agonist of proliferation-activated receptor γ (PPARγ), TZDs exhibited no correlation between their anti-ferroptosis ability and PPAR-γ-mediated gene transcription (Doll et al 2017 ).…”

Multi-omics profiling identifies microglial Annexin A2 as a key mediator of NF-κB pro-inflammatory signaling in ischemic reperfusion injury

“…Cerebral stroke is a devastating and debilitating cerebrovascular disease, that causes high disability and mortality, and has emerged as one of the major public health issues around the world ( 1 , 2 , 3 ). More than 80% of cerebral strokes are ischemic stroke ( 4 , 5 , 6 ).…”