Sexual Dimorphism in Brain Sirtuin-1 and m6A Methylated Sirtuin-1 mRNA, and in Protection with Post-Injury Anti-miR-200c treatment, after Experimental Stroke in Aged Mice

The Aging Immune System: A Critical Attack on Ischemic Stroke

Ischemic stroke caused by cerebrovascular embolism is an age-related disease with high rates of disability and mortality. Although the mechanisms of immune and inflammatory development after stroke have been of great interest, most studies have neglected the critical and unavoidable factor of age. As the global aging trend intensifies, the number of stroke patients is constantly increasing, emphasizing the urgency of finding effective measures to address the needs of elderly stroke patients. The concept of "immunosenescence" appears to explain the worse stroke outcomes in older individuals. Immune remodeling due to aging involves dynamic changes at all levels of the immune system, and the overall consequences of central (brain-resident) and peripheral (non-brain-resident) immune cells in stroke vary according to the age of the individual. Lastly, the review outlines recent strategies aimed at immunosenescence to improve stroke prognosis.

Microglia Autophagy Mediated by TMEM166 Promotes Ischemic Stroke Secondary to Carotid Artery Stenosis

Ischemic stroke can be a serious complication of selective carotid endarterectomy (CEA) in patients with carotid artery stenosis (CAS). The underlying risk factors and mechanisms of these postoperative strokes are not completely understood. Our previous study showed that TMEM166-induced neuronal autophagy is involved in the development of secondary brain injury following cerebral ischemia-reperfusion injury in rats. This current study aimed to investigate the role of TMEM166 in ischemic stroke following CEA. In the clinical part of this study, the quantitative analysis demonstrated circulating TMEM166, interleukin 6 (IL-6), and C-reactive protein (CRP) levels were significantly elevated in patients who suffered an ischemic stroke after CEA compared to those who did not. Furthermore, non-survivors exhibited higher levels of these proteins than survivors. In the preclinical part of this study, a middle cerebral artery occlusion (MCAO) model was implemented following CAS simulation in TMEM166-/- mice. We found TMEM166 expression was positively correlated with the degree of ischemic brain injury. Ad5-TMEM166 transfection aggravated ischemic brain injury by inducing microglial autophagy activation and release of inflammatory cytokines. Accordingly, TMEM166 deficiency reduced brain inflammation and inhibited excessive microglial autophagy through the mammalian target of rapamycin (mTOR) pathway. These findings suggest that TMEM166 may play a key role in the development of ischemic injury after CEA and may serve as a biomarker for risk assessment of postoperative ischemic stroke.

Sex-based differences in short- and longer-term diet-induced metabolic heart disease

Sex-based differences in the development of obesity-induced cardiometabolic dysfunction are well documented, however, the specific mechanisms are not completely understood. Obesity has been linked to dysregulation of the epitranscriptome, but the role of N6-methyladenosine (m6A) RNA methylation has not been investigated in relation to the sex differences during obesity-induced cardiac dysfunction. In the current study, male and female C57BL/6J mice were subjected to short- and long-term high-fat/high-sucrose (HFHS) diet to induce obesogenic stress. Cardiac echocardiography showed males developed systolic and diastolic dysfunction after 4 mo of diet, but females maintained normal cardiac function despite both sexes being metabolically dysfunctional. Cardiac m6A machinery gene expression was differentially regulated by duration of HFHS diet in male, but not female mice, and left ventricular ejection fraction correlated with RNA machinery gene levels in a sex- and age-dependent manner. RNA-sequencing of cardiac transcriptome revealed that females, but not males may undergo protective cardiac remodeling early in the course of obesogenic stress. Taken together, our study demonstrates for the first time that cardiac RNA methylation machinery genes are regulated early during obesogenic stress in a sex-dependent manner and may play a role in the sex differences observed in cardiometabolic dysfunction.NEW & NOTEWORTHY Sex differences in obesity-associated cardiomyopathy are well documented but incompletely understood. We show for the first time that RNA methylation machinery genes may be regulated in response to obesogenic diet in a sex- and age-dependent manner and levels may correspond to cardiac systolic function. Our cardiac RNA-seq analysis suggests female, but not male mice may be protected from cardiac dysfunction by a protective cardiac remodeling response early during obesogenic stress.

Pan-cancer analysis of RNA 5-methylcytosine reader (ALYREF)

The increasing interest in RNA modifications has significantly advanced epigenomic and epitranscriptomic technologies. This study focuses on the immuno-oncological impact of ALYREF in human cancer through a pan-cancer analysis, enhancing understanding of this gene's role in cancer. We observed differential ALYREF expression between tumor and normal samples, correlating strongly with prognosis in various cancers, particularly kidney renal papillary cell carcinoma (KIRP) and liver hepatocellular carcinoma (LIHC). ALYREF showed a negative correlation with most tumor-infiltrating cells in lung squamous cell carcinoma (LUSC) and lymphoid neoplasm diffuse large B-cell lymphoma (DLBC), while positive correlations were noted in LIHC, kidney chromophobe (KICH), mesothelioma (MESO), KIRP, pheochromocytoma and paraganglioma (PARD), and glioma (GBMLGG). Additionally, ALYREF expression was closely associated with tumor heterogeneity, stemness indices, and a high mutation rate in TP53 across these cancers. In conclusion, ALYREF may serve as an oncogenic biomarker in numerous cancers, meriting further research attention.