Fisetin alleviates cerebral ischemia/reperfusion injury by regulating Sirt1/Foxc1/Ubqln1 pathway-mediated proteostasis

Int Immunopharmacol. 2024 Mar 30:130:111742. doi: 10.1016/j.intimp.2024.111742. Epub 2024 Mar 7.

Abstract

Background: Cerebral ischemia/reperfusion injury (IRI) is pathologically associated with protein damage. The flavonoid fisetin has good therapeutic effects on cerebral IRI. However, the role of fisetin in regulating protein damage during cerebral IRI development remains unclear. This study investigated the pharmacological effects of fisetin on protein damage during cerebral IRI progression and defined the underlying mechanism of action.

Methods: In vivo and in vitro models of cerebral IRI were established by middle cerebral artery occlusion/reperfusion (MACO/R) and oxygen-glucose deprivation/reperfusion (OGD/R) treatment, respectively. Triphenyl tetrazolium chloride staining was performed to detect cerebral infarct size, and the modified neurologic severity score was used to examine neurological deficits. LDH activity and protein damage were assessed using kits. HT22 cell vitality and apoptosis were examined using CCK-8 assay and TUNEL staining, respectively. Interactions between Foxc1, Ubqln1, Sirt1, and Ezh2 were analyzed using CoIP, ChIP and/or dual-luciferase reporter gene assays.

Results: Fisetin alleviated protein damage and ubiquitinated protein aggregation and neuronal death caused by MCAO/R and OGD/R. Ubqln1 knockdown abrogated the inhibitory effect of fisetin on OGD/R-induced protein damage, ubiquitinated protein aggregation, and neuronal death in HT22 cells. Further experiments demonstrated that Foxc1 functions as a transcriptional activator of Ubqln1 and that Sirt1 promotes Foxc1 expression by deacetylating Ezh2 and inhibiting its activity. Furthermore, Sirt1 knockdown abrogated fisetin-mediated biological effects on OGD/R-treated HT22 cells.

Conclusion: Fisetin improved proteostasis during cerebral IRI by regulating the Sirt1/Foxc1/Ubqln1 signaling axis. Our findings strongly suggest that fisetin-mediated inhibition of protein damage after ischemic stroke is a part of the mechanism through which fisetin is neuroprotective in cerebral IRI.

Keywords: Cerebral ischemia/reperfusion injury; Fisetin; Proteostasis; Sirt1; Ubqln1.

MeSH terms

  • Adaptor Proteins, Signal Transducing* / metabolism
  • Animals
  • Apoptosis
  • Autophagy-Related Proteins* / metabolism
  • Brain Ischemia* / drug therapy
  • Flavonols* / pharmacology
  • Flavonols* / therapeutic use
  • Forkhead Transcription Factors* / metabolism
  • Infarction, Middle Cerebral Artery / drug therapy
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Protein Aggregates
  • Proteostasis* / drug effects
  • Reperfusion Injury* / drug therapy
  • Sirtuin 1* / metabolism

Substances

  • fisetin
  • Flavonols
  • Protein Aggregates
  • Sirtuin 1
  • Foxc1 protein, mouse
  • UBQLN1 protein, mouse
  • Forkhead Transcription Factors
  • Autophagy-Related Proteins
  • Adaptor Proteins, Signal Transducing