Project description:Background: Exposure to pollutants including the ubiquitous ‘forever chemical’, Perfluorooctane sulfonate (PFOS) has increasingly been associated with metabolic dysfunction-associated steatotic liver disease (MASLD). Recent epidemiological evidence has identified associations between Per- and polyfluoroalkyl substances (PFAS) exposure and increased liver injury in alcohol consumers, suggesting potential interactions between these exposures. However, the intersection of pollutant exposures and alcohol-associated liver disease (ALD) is not well studied. We hypothesize that pollutants may disrupt hepatic metabolism to modify ALD severity. Recently, we developed a two-hit (ethanol plus pollutant) mouse model, enabling testing of this hypothesis. Here, we elucidate the metabolic and disease-modifying effects of PFOS in this model. Methods: Male C57BL/6J mice were fed isocaloric control or 5% Ethanol (EtOH) Lieber-DeCarli diet for 15 days. From day 6 of feeding, mice were concurrently gavaged with 1 mg/kg PFOS or 2% tween-80 vehicle for 10 days, followed by a 5 g/kg EtOH binge dose and euthanized 5-6 hours later. Results: Approximately 60% of the administered PFOS dose accumulated in liver. PFOS exacerbated EtOH-induced hepatic steatosis and was associated by higher levels of plasma very low-density lipoprotein (vLDL) and alanine aminotransferase (ALT). PFOS upregulated hepatic ethanol-metabolizing enzymes and lowered blood alcohol levels. Ingenuity Pathway Analysis (IPA) Top Toxicity Functions/Lists associated with hepatic gene expression following PFOS co-exposure in EtOH-fed mice included: fatty acid metabolism and liver steatosis; nuclear receptor activation, cytochrome P450, and reactive oxygen species (ROS); apoptosis; liver fibrosis; and hepatocellular carcinoma (HCC). GO/KEGG analyses similarly revealed enrichment in fatty acid, xenobiotic, alcohol, or glutathione metabolic processes; and Peroxisome proliferator-activated receptor (PPAR) signaling. PFOS upregulated hepatic expression of several nuclear receptors (e.g., Pparα, Car, and Pxr) and their P450 target genes (e.g., Cyp4a10, Cyp2b10, and Cyp3a11) by RT-PCR or Western blot, confirming key IPA predictions. Conclusions: PFOS is a metabolism disrupting chemical that worsened ALD severity. PFOS activated hepatic nuclear receptors and enriched hepatic transcriptional pathways associated with steatosis, xenobiotic metabolism, oxidative stress, cell death, fibrosis, and HCC. These data demonstrate a novel mechanism whereby PFOS exacerbates ALD through coordinated dysregulation of lipid homeostasis and liver injury, potentially mediated by nuclear receptor activation. The identification of PFOS as an ALD risk modifier highlight the critical need to evaluate environmental pollutants as potential contributors to liver disease progression in vulnerable populations. More data are required on environmental pollution as a disease modifying factor in ALD.

Project description:Background. Skeletal muscle is a major target organ for ethanol induced perturbations with resultant sarcopenia in alcohol-related liver disease (ALD). Targeted studies show that in skeletal muscle, ethanol causes mitochondrial oxidative dysfunction and impaired mTORC1 signaling with consequent decreased protein synthesis and increased autophagy. However, complex interactions and pathway intersections involved in cellular adaptive and maladaptive responses are not well understood. Unlike hypotheses driven focused experiments, an integrated multiomics-experimental validation approach helps identify the global landscape of complex, interacting perturbations in the skeletal muscle. Methods. We used an integrated multiomics approach in a comprehensive array of models, including murine and human induced pluripotent stem cell-derived myotubes (hiPSCm), skeletal muscle from a mouse model of ALD (mALD), and human patients with alcohol-related cirrhosis (CIR) and controls (CON), to identify novel regulatory mechanisms of sarcopenia in ALD. We generated 13 untargeted datasets, including chromosomal conformation, RNA sequencing, proteomics, phosphoproteomics, acetylomics, and metabolomics and conducted a comprehensive analysis using upset plots and feature extraction-based approaches. The most altered molecular interactions were experimentally validated in different models using immunoblots, redox measurements, imaging methods, and measures of senescence associated molecular phenotype (SAMP). Redox ratio was reversed using mitochondrial targeted Lactobacillus brevis NADH oxidase (MitoLbNOX). Results. Enrichments in mitochondrial oxidative function, protein synthesis, and senescence pathways were identified. Multiomics analyses were consistent with the known effects of hypoxia inducible factor 1 (HIF1) that inhibits mitochondrial oxidative dysfunction and promotes skeletal muscle senescence. Pertubrations in genes in the nicotinamide dinucleotide-related pathways including sirtuin signaling, known regulators of senescence, was also noted with ethanol treatment. Experimentally, HIF1 protein was stabilized in myotubes and muscle tissue without cellular hypoxia. Mitochondrial electron transport chain protein expression was less in murine myotubes and hiPSCm with lower redox ratio, less expression of sirtuins, and increased acetylation of mitochondrial proteins. SAMP noted in multiple models in response to ethanol exposure and reversing redox ratio with MitoLbNOX prevented HIF1a stabilization and SAMP in murine myotubes. Conclusions. Our integrated multiomics analyses combined with complementary experimental validation, identify HIF1a stabilization with accelerated skeletal muscle post-mitotic senescence as novel mechanisms of sarcopenia in ALD, highlighting the complex interactions that result in mitochondrial dysfunction with persistent and progressive sarcopenia in ALD.

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	210302D_Irene_10_control_S1-D10_1_1109.RAW	Raw
	210302D_Irene_11_control_S1-D11_1_1110.RAW	Raw
	210302D_Irene_12_control_S1-D12_1_1111.RAW	Raw
	210302D_Irene_13_control_S1-E1_1_1112.RAW	Raw
	210302D_Irene_14_control_S1-E2_1_1113.RAW	Raw

Dataset Information

Modulatory Effects of CNNM4 on Protein-L-Isoaspartyl-O-Methyltransferase Repair Function during Alcohol-Induced Hepatic Damage

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Modulatory effects of CNNM4 on protein- l -isoaspartyl- O -methyltransferase repair function during alcohol-induced hepatic damage.

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