Src inhibition rescues FUNDC1-mediated neuronal mitophagy in ischaemic stroke

Tianchi Tang; Li-Bin Hu; Chao Ding; Zhihua Zhang; Ning Wang; Tingting Wang; Hang Zhou; Siqi Xia; Linfeng Fan; Xiong-Jie Fu; Feng Yan; Xiangnan Zhang; Gao Chen; Jianru Li

doi:10.1136/svn-2023-002606

Src inhibition rescues FUNDC1-mediated neuronal mitophagy in ischaemic stroke

Stroke Vasc Neurol. 2023 Oct 4:svn-2023-002606. doi: 10.1136/svn-2023-002606. Online ahead of print.

Authors

Tianchi Tang^#¹, Li-Bin Hu^#², Chao Ding³, Zhihua Zhang³, Ning Wang³, Tingting Wang³, Hang Zhou¹, Siqi Xia¹, Linfeng Fan¹, Xiong-Jie Fu², Feng Yan¹, Xiangnan Zhang⁴, Gao Chen², Jianru Li⁵

Affiliations

¹ Department of Neurosurgery, Zhejiang University School of Medicine Second Affiliated Hospital, Hangzhou, Zhejiang, China.
² Neurosurgery, Zhejiang University School of Medicine Second Affiliated Hospital, Hangzhou, Zhejiang, China.
³ Zhejiang University School of Medicine, Hangzhou, Zhejiang, China.
⁴ Zhejiang University Department of Pharmacology, Hangzhou, Zhejiang, China.
⁵ Department of Neurosurgery, Zhejiang University School of Medicine Second Affiliated Hospital, Hangzhou, Zhejiang, China lijianru@zju.edu.cn.

^# Contributed equally.

PMID: 37793899
DOI: 10.1136/svn-2023-002606

Abstract

Background: Ischaemic stroke triggers neuronal mitophagy, while the involvement of mitophagy receptors in ischaemia/reperfusion (I/R) injury-induced neuronal mitophagy remain not fully elucidated. Here, we aimed to investigate the involvement of mitophagy receptor FUN14 domain-containing 1 (FUNDC1) and its modulation in neuronal mitophagy induced by I/R injury.

Methods: Wild-type and FUNDC1 knockout mice were generated to establish models of neuronal I/R injury, including transient middle cerebral artery occlusion (tMCAO) in vivo and oxygen glucose deprivation/reperfusion in vitro. Stroke outcomes of mice with two genotypes were assessed. Neuronal mitophagy was analysed both in vivo and in vitro. Activities of FUNDC1 and its regulator Src were evaluated. The impact of Src on FUNDC1-mediated mitophagy was assessed through administration of Src antagonist PP1.

Results: To our surprise, FUNDC1 knockout mice subjected to tMCAO showed stroke outcomes comparable to those of their wild-type littermates. Although neuronal mitophagy could be activated by I/R injury, FUNDC1 deletion did not disrupt neuronal mitophagy. Transient activation of FUNDC1, represented by dephosphorylation of Tyr18, was detected in the early stages (within 3 hours) of neuronal I/R injury; however, phosphorylated Tyr18 reappeared and even surpassed baseline levels in later stages (after 6 hours), accompanied by a decrease in FUNDC1-light chain 3 interactions. Spontaneous inactivation of FUNDC1 was associated with Src activation, represented by phosphorylation of Tyr416, which changed in parallel with the level of phosphorylated FUNDC1 (Tyr18) during neuronal I/R injury. Finally, FUNDC1-mediated mitophagy in neurons under I/R conditions can be rescued by pharmacological inhibition of Src.

Conclusions: FUNDC1 is inactivated by Src during the later stage (after 6 hours) of neuronal I/R injury, and rescue of FUNDC1-mediated mitophagy may serve as a potential therapeutic strategy for treating ischaemic stroke.

Keywords: Stroke.