Histone Methyltransferases SUV39H1 and G9a and DNA Methyltransferase DNMT1 in Penumbra Neurons and Astrocytes after Photothrombotic Stroke

Abstract

Background: Cerebral ischemia, a common cerebrovascular disease, is one of the great threats to human health and new targets for stroke therapy are needed. The transcriptional activity in the cell is regulated by epigenetic processes such as DNA methylation/demethylation, acetylation/deacetylation, histone methylation, etc. Changes in DNA methylation after ischemia can have both neuroprotective and neurotoxic effects depending on the degree of ischemia damage, the time elapsed after injury, and the site of methylation. Methods: In this study, we investigated the changes in the expression and intracellular localization of DNA methyltransferase DNMT1, histone methyltransferases SUV39H1, and G9a in penumbra neurons and astrocytes at 4 and 24 h after stroke in the rat cerebral cortex using photothrombotic stroke (PTS) model. Methods of immunofluorescence microscopy analysis, apoptosis analysis, and immunoblotting were used. Additionally, we have studied the effect of DNMT1 and G9a inhibitors on the volume of PTS-induced infarction and apoptosis of penumbra cells in the cortex of mice after PTS. Results: This study has shown that the level of DNMT1 increased in the nuclear and cytoplasmic fractions of the penumbra tissue at 24 h after PTS. Inhibition of DNMT1 by 5-aza-2′-deoxycytidine protected cells of PTS-induced penumbra from apoptosis. An increase in the level of SUV39H1 in the penumbra was found at 24 h after PTS and G9a was overexpressed at 4 and 24 h after PTS. G9a inhibitors A-366 and BIX01294 protected penumbra cells from apoptosis and reduced the volume of PTS-induced cerebral infarction. Conclusion: Thus, the data obtained show that DNA methyltransferase DNMT1 and histone methyltransferase G9a can be potential protein targets in ischemic penumbra cells, and their inhibitors are potential neuroprotective agents capable of protecting penumbra cells from postischemic damage to the cerebral cortex.

Neuroprotective Effect of Polyherbal Recipe Containing Ginger, Chinese Date, and Wood Ear Mushroom against Ischemic Stroke with Metabolic Syndrome Condition via Epigenetic Modification of Inflammation and Oxidative Stress

“…Recently, the role of epigenetic mechanism in the regulation of gene transcription in stroke has been clearly revealed [26,33]. The current data showed the elevation of DNMT1 and HDAC3 in cerebral ischemia corresponding with the changes in the previous studies [34][35][36][37][38][39]. These changes are associated with brain edema [40], neuronal loss, neuronal deficit, and neuronal recovery in cerebral ischemia [41].…”

The Role of DNA Methylation in Stroke Recovery

“…In neuronal cell death including apoptosis after stroke, DNMTs, DNMT1, and DNMT3a expression regulates increased or decreased global DNA methylation [ 8 , 9 , 12 , 26 , 58 , 143 ]. Fetal hypoxia induced a decrease in GR expression by increased DNA methylation in the hippocampus of neonatal mice, as well as increased susceptibility of the brain to hypoxia–ischemic injury [ 60 ].…”

“…In another animal model of photothrombotic stroke (PTS), the level of DNMT1 was increased in the nuclear fraction of neurons and in the cytoplasmic fraction of astrocytes in the penumbra tissue at 24 h after PTS induction; furthermore, apoptosis was induced. Inhibition of DNMT1 by 5-aza-dC protected against PTS-induced apoptosis in the penumbra at 4 days, as well as 24 h after PTS [ 58 ]. The effect of altered DNA methylation using 5-aza-dC on neuronal apoptosis was also confirmed in an experiment with mouse hippocampus-derived neuronal HT22 cells.…”

Lysosomal-associated transmembrane protein 5 deficiency exacerbates cerebral ischemia/reperfusion injury

“… Endres et al (2000) found that DNA methylation levels were upregulated after focal cerebral ischemia and correlated with poor prognosis. Pharmacological inhibition or gene knockout of DNA methyltransferases (DNMTs) can alleviate ischemic brain injury and increase neuronal survival ( Dock et al, 2015 ; Sharifulina et al, 2021 ). In our study, cerebral I/R treatment may increase DNA methylation, resulting in decreased LAPTM5 expression.…”