Usf2 Deficiency Promotes Autophagy to Alleviate Cerebral Ischemia-Reperfusion Injury Through Suppressing YTHDF1-m6A-Mediated Cdc25A Translation

m6A reader YTHDC2 mediates NCOA4 mRNA stability affecting ferritinophagy to alleviate secondary injury after intracerebral haemorrhage

Oxidative stress and neuronal dysfunction caused by intracerebral haemorrhage (ICH) can lead to secondary injury. The m6A modification has been implicated in the progression of ICH. This study aimed to investigate the role of the m6A reader YTHDC2 in ICH-induced secondary injury. ICH models were established in rats using autologous blood injection, and neuronal cell models were induced with Hemin. Experiments were conducted to overexpress YTH domain containing 2 (YTHDC2) and examine its effects on neuronal dysfunction, brain injury, and neuronal ferritinophagy. RIP-qPCR and METTL3 silencing were performed to investigate the regulation of YTHDC2 on nuclear receptor coactivator 4 (NCOA4). Finally, NCOA4 overexpression was used to validate the regulatory mechanism of YTHDC2 in ICH. The study found that YTHDC2 expression was significantly downregulated in the brain tissues of ICH rats. However, YTHDC2 overexpression improved neuronal dysfunction and reduced brain water content and neuronal death after ICH. Additionally, it reduced levels of ROS, NCOA4, PTGS2, and ATG5 in the brain tissues of ICH rats, while increasing levels of FTH and FTL. YTHDC2 overexpression also decreased levels of MDA and Fe2+ in the serum, while promoting GSH synthesis. In neuronal cells, YTHDC2 overexpression alleviated Hemin-induced injury, which was reversed by Erastin. Mechanistically, YTHDC2-mediated m6A modification destabilized NCOA4 mRNA, thereby reducing ferritinophagy and alleviating secondary injury after ICH. However, the effects of YTHDC2 were counteracted by NCOA4 overexpression. Overall, YTHDC2 plays a protective role in ICH-induced secondary injury by regulating NCOA4-mediated ferritinophagy.

USF2 and TFEB compete in regulating lysosomal and autophagy genes

Autophagy, a highly conserved self-digestion process crucial for cellular homeostasis, is triggered by various environmental signals, including nutrient scarcity. The regulation of lysosomal and autophagy-related processes is pivotal to maintaining cellular homeostasis and basal metabolism. The consequences of disrupting or diminishing lysosomal and autophagy systems have been investigated; however, information on the implications of hyperactivating lysosomal and autophagy genes on homeostasis is limited. Here, we present a mechanism of transcriptional repression involving upstream stimulatory factor 2 (USF2), which inhibits lysosomal and autophagy genes under nutrient-rich conditions. We find that USF2, together with HDAC1, binds to the CLEAR motif within lysosomal genes, thereby diminishing histone H3K27 acetylation, restricting chromatin accessibility, and downregulating lysosomal gene expression. Under starvation, USF2 competes with transcription factor EB (TFEB), a master transcriptional activator of lysosomal and autophagy genes, to bind to target gene promoters in a phosphorylation-dependent manner. The GSK3β-mediated phosphorylation of the USF2 S155 site governs USF2 DNA-binding activity, which is involved in lysosomal gene repression. These findings have potential applications in the treatment of protein aggregation-associated diseases, including α1-antitrypsin deficiency. Notably, USF2 repression is a promising therapeutic strategy for lysosomal and autophagy-related diseases.

N6-methyladenosine demethylase ALKBH5 homologous protein protects against cerebral I/R injury though suppressing SNHG3-mediated neural PANoptosis: Involvement of m6A-related macromolecules in the diseases of nervous system

In order to address this gap in knowledge, the present study utilized both in vivo and in vitro models to investigate the role of the m6A demethylase ALKBH5 in protecting against cerebral I/R injury by inhibiting PANoptosis (Pytoptosis, Ppoptosis, and Necroptosis) in an m6A-dependent manner. They observed that ALKBH5, the predominant m6A demethylase, was downregulated in these models, while SNHG3 and PANoptosis-related proteins (ZBP1, AIM2, Cappase-3, Caspase-8, cleaved Caspase-1, GSDMD-N, and p-MLKL) were elevated. Additionally, both ALKBH5 overexpression and SNHG3-deficiency were found to ameliorate PANoptosis and injury induced by OGD/reperfusion and OGD/RX in both mice tissues and astrocyte cells. Further experiments demonstrated that ALKBH5 induced m6A-demethylation in SNHG3, leading to its degradation. Low expression of SNHG3, on the other hand, prevented the formation of the SNHG3-ELAVL1-ZBP1/AIM2 complex, which in turn destabilized ZBP1 and AIM2 mRNA, resulting in the downregulation of these PANoptosis-related genes. Ultimately, the rescue experiments provided evidence that ALKBH5 protected against PANoptosis in cerebral I/R injury models through the inhibition of SNHG3.This study sheds light on the intricate molecular mechanisms involved in the pathogenesis of cerebral I/R injury and highlights the potential of m6A-related genes as therapeutic targets in this condition.