bims-caglex 2024-02-04 papers

Aging Cell. 2024 Feb 01. e14077

The SATB1-MIR22-GBA axis mediates glucocerebroside accumulation inducing a cellular senescence-like phenotype in dopaminergic neurons.

Taylor Russo, Benjamin Kolisnyk, Aswathy B S, Jonathan Plessis-Belair, Tae Wan Kim, Jacqueline Martin, Jason Ni, Jordan A Pearson, Emily J Park, Roger B Sher, Lorenz Studer, Markus Riessland.

Idiopathic Parkinson's disease (PD) is characterized by the loss of dopaminergic neurons in the substantia nigra pars compacta, which is associated with neuroinflammation and reactive gliosis. The underlying cause of PD and the concurrent neuroinflammation are not well understood. In this study, we utilize human and murine neuronal lines, stem cell-derived dopaminergic neurons, and mice to demonstrate that three previously identified genetic risk factors for PD, namely SATB1, MIR22HG, and GBA, are components of a single gene regulatory pathway. Our findings indicate that dysregulation of this pathway leads to the upregulation of glucocerebrosides (GluCer), which triggers a cellular senescence-like phenotype in dopaminergic neurons. Specifically, we discovered that downregulation of the transcriptional repressor SATB1 results in the derepression of the microRNA miR-22-3p, leading to decreased GBA expression and subsequent accumulation of GluCer. Furthermore, our results demonstrate that an increase in GluCer alone is sufficient to impair lysosomal and mitochondrial function, thereby inducing cellular senescence. Dysregulation of the SATB1-MIR22-GBA pathway, observed in both PD patients and normal aging, leads to lysosomal and mitochondrial dysfunction due to the GluCer accumulation, ultimately resulting in a cellular senescence-like phenotype in dopaminergic neurons. Therefore, our study highlights a novel pathway involving three genetic risk factors for PD and provides a potential mechanism for the senescence-induced neuroinflammation and reactive gliosis observed in both PD and normal aging.

Keywords: MicroRNAs; Parkinson's disease; gene expression regulation; glucosylceramides; lysosomes; mitochondria; neuroinflammation; senescence

DOI: https://doi.org/10.1111/acel.14077

J Cardiovasc Transl Res. 2024 Jan 31.

Therapeutic Strategies for Angiogenesis Based on Endothelial Cell Epigenetics.

Yue Cai, Lihua Li, Chen Shao, Yiliu Chen, Zhongqun Wang.

With the in-depth investigation of various diseases, angiogenesis has gained increasing attention. Among the contributing factors to angiogenesis research, endothelial epigenetics has emerged as an influential player. Endothelial epigenetic therapy exerts its regulatory effects on endothelial cells by controlling gene expression, RNA, and histone modification within these cells, which subsequently promotes or inhibits angiogenesis. As a result, this therapeutic approach offers potential strategies for disease treatment. The purpose of this review is to outline the pertinent mechanisms of endothelial cell epigenetics, encompassing glycolysis, lactation, amino acid metabolism, non-coding RNA, DNA methylation, histone modification, and their connections to specific diseases and clinical applications. We firmly believe that endothelial cell epigenetics has the potential to become an integral component of precision medicine therapy, unveiling novel therapeutic targets and providing new directions and opportunities for disease treatment.

Keywords: Angiogenesis; Endothelial cell; Epigenetics

DOI: https://doi.org/10.1007/s12265-024-10485-y

BMC Gastroenterol. 2024 Feb 02. 24(1): 59

Dietary intervention reverses molecular markers of hepatocellular senescence in the GAN diet-induced obese and biopsy-confirmed mouse model of NASH.

Mathias Flensted-Jensen, Denise Oró, Emma A Rørbeck, Chen Zhang, Martin Rønn Madsen, Andreas Nygaard Madsen, Jenny Norlin, Michael Feigh, Steen Larsen, Henrik H Hansen.

BACKGROUND: Hepatocellular senescence may be a causal factor in the development and progression of non-alcoholic steatohepatitis (NASH). The most effective currently available treatment for NASH is lifestyle intervention, including dietary modification. This study aimed to evaluate the effects of dietary intervention on hallmarks of NASH and molecular signatures of hepatocellular senescence in the Gubra-Amylin NASH (GAN) diet-induced obese (DIO) and biopsy-confirmed mouse model of NASH.
METHODS: GAN DIO-NASH mice with liver biopsy-confirmed NASH and fibrosis received dietary intervention by switching to chow feeding (chow reversal) for 8, 16 or 24 weeks. Untreated GAN DIO-NASH mice and chow-fed C57BL/6J mice served as controls. Pre-to-post liver biopsy histology was performed for within-subject evaluation of NAFLD Activity Score and fibrosis stage. Terminal endpoints included blood/liver biochemistry, quantitative liver histology, mitochondrial respiration and RNA sequencing.
RESULTS: Chow-reversal promoted substantial benefits on metabolic outcomes and liver histology, as demonstrated by robust weight loss, complete resolution of hepatomegaly, hypercholesterolemia, elevated transaminase levels and hepatic steatosis in addition to attenuation of inflammatory markers. Notably, all DIO-NASH mice demonstrated ≥ 2 point significant improvement in NAFLD Activity Score following dietary intervention. While not improving fibrosis stage, chow-reversal reduced quantitative fibrosis markers (PSR, collagen 1a1, α-SMA), concurrent with improved liver mitochondrial respiration, complete reversal of p21 overexpression, lowered γ-H2AX levels and widespread suppression of gene expression markers of hepatocellular senescence.
CONCLUSIONS: Dietary intervention (chow reversal) substantially improves metabolic, biochemical and histological hallmarks of NASH and fibrosis in GAN DIO-NASH mice. These benefits were reflected by progressive clearance of senescent hepatocellular cells, making the model suitable for profiling potential senotherapeutics in preclinical drug discovery for NASH.

Keywords: Animal model; Dietary intervention; Fibrosis; Hepatocellular senescence; Mitochondrial respiration; Non-alcoholic steatohepatitis

DOI: https://doi.org/10.1186/s12876-024-03141-x