Perilipin 5 regulates hepatic stellate cell activation and high-fat diet-induced non-alcoholic fatty liver disease

Background:Nonalcoholic fatty liver disease(NAFLD)is one of the most common chronic liver diseases globally.Hepatic stellate cells(HSCs)are the major effector cells of liver fibrosis.HSCs contain abundant lipid droplets(LDs)in their cytoplasm during quiescence.Perilipin 5(PLIN 5)is a LD surface-associated protein that plays a crucial role in lipid homeostasis.However,little is known about the role of PLIN 5 in HSC activation.Methods:PLIN 5 was overexpressed in HSCs of Sprague–Dawley rats by lentivirus transfection.At the same time,PLIN 5 gene knockout mice were constructed and fed with a high-fat diet(HFD)for 20 weeks to study the role of PLIN 5 in NAFLD.The corresponding reagent kits were used to measure TG,GSH,Caspase 3 activity,ATP level,and mitochondrial DNA copy number.Metabolomic analysis of mice liver tissue metabolism was performed based on UPLC-MS/MS.AMPK,mitochondrial function,cell proliferation,and apoptosis-related genes and proteins were detected by western blotting and qPCR.Results:Overexpression of PLIN 5 in activated HSCs led to a decrease in ATP levels in mitochondria,inhibition of cell proliferation,and a significant increase in cell apoptosis through AMPK activation.In addition,compared with the HFD-fed C57BL/6J mice,PLIN 5 knockout mice fed with HFD showed reduced liver fat deposition,decreased LD abundance and size,and reduced liver fibrosis.Conclusion:These findings highlight the unique regulatory role of PLIN 5 in HSCs and the role of PLIN 5 in the fibrosis process of NAFLD.

NAD+associated genes as potential biomarkers for predicting the prognosis of gastric cancer

Nicotinamide adenine dinucleotide(NAD+)plays an essential role in cellular metabolism,mitochondrial homeostasis,inflammation,and senescence.However,the role of NAD+-regulated genes,including coding and long non-coding genes in cancer development is poorly understood.We constructed a prediction model based on the expression level of NAD+metabolism-related genes(NMRGs).Furthermore,we validated the expression of NMRGs in gastric cancer(GC)tissues and cell lines;additionally,β-nicotinamide mononucleotide(NMN),a precursor of NAD+,was used to treat the GC cell lines to analyze its effects on the expression level of NMRGs lncRNAs and cellular proliferation,cell cycle,apoptosis,and senescence-associated secretory phenotype(SASP).A total of 13 NMRGs-related lncRNAs were selected to construct prognostic risk signatures,and patients with high-risk scores had a poor prognosis.Some immune checkpoint genes were upregulated in the high-risk group.In addition,cell cycle,epigenetics,and senescence were significantly downregulated in the high-risk group.Notably,we found that the levels of immune cell infiltration,including CD8 T cells,CD4 naïve T cells,CD4 memory-activated T cells,B memory cells,and naïve B cells,were significantly associated with risk scores.Furthermore,the treatment of NMN showed increased proliferation of AGS and MKN45 cells.In addition,the expression of SASP factors(IL6,IL8,IL10,TGF-β,and TNF-α)was significantly decreased after NMN treatment.We conclude that the lncRNAs associated with NAD+metabolism can potentially be used as biomarkers for predicting clinical outcomes of GC patients.

cGAS regulates the DNA damage response to maintain proliferative signaling in gastric cancer cells

The activation of some oncogenes promote cancer cell proliferation and growth,facilitate cancer progression and metastasis by induce DNA replication stress,even genome instability.Activation of the cyclic GMP-AMP synthase(cGAS)mediates classical DNA sensing,is involved in genome instability,and is linked to various tumor development or therapy.However,the function of cGAS in gastric cancer remains elusive.In this study,the TCGA database and retrospective immunohistochemical analyses revealed substantially high cGAS expression in gastric cancer tissues and cell lines.By employing cGAS high-expression gastric cancer cell lines,including AGS and MKN45,ectopic silencing of cGAS caused a significant reduction in the proliferation of the cells,tumor growth,and mass in xenograft mice.Mechanistically,database analysis predicted a possible involvement of cGAS in the DNA damage response(DDR),further data through cells revealed protein interactions of the cGAS and MRE11-RAD50-NBN(MRN)complex,which activated cell cycle checkpoints,even increased genome instability in gastric cancer cells,thereby contributing to gastric cancer progression and sensitivity to treatment with DNA damaging agents.Furthermore,the upregulation of cGAS significantly exacerbated the prognosis of gastric cancer patients while improving radiotherapeutic outcomes.Therefore,we concluded that cGAS is involved in gastric cancer progression by fueling genome instability,implying that intervening in the cGAS pathway could be a practicable therapeutic approach for gastric cancer.