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Biomedical subjects

Ramon Bataller

Publications and source records attributed to Ramon Bataller.

3 recordsLinked to original sources

Unbiased Spatial Proteomics Uncovers Hepatic in Situ Regulation in Alcohol-Associated Hepatitis.

Alcohol-associated hepatitis (AH) is an acute inflammatory form of alcohol-associated liver disease. Previous studies have explored molecular mechanisms associated with AH pathogenesis through bulk liver tissue analysis; however, the heterogeneity of liver tissue and hence the spatial regulation within the AH liver microenvironment remained unaddressed. Here, an unbiased spatial proteomics analysis on the pathologic regions (PRs) of AH liver tissue is presented, including immune cell infiltration foci, lipid droplets, chicken-wire fibrosis, and fibrotic bands. Through combining a highly efficient nanodroplet processing in one pot for trace samples platform with ultrasensitive liquid chromatography-mass spectrometry, this study identified and quantified a total of 5186 unique proteins from PRs isolated in 200-μm-long × 200-μm-wide × 10-μm-thick areas. This in-depth spatial proteome coverage allowed us to discover mechanistic regulations within individual PRs, including compromised resolution of inflammation with infiltrated neutrophils at infiltration foci, increase of mitochondrial and peroxisomal fatty acid β-oxidation at lipid droplets, and differential cellular and extracellular regulations between chicken-wire fibrosis and fibrotic bands. Overall, this study demonstrated a new capability for AH research, revealed the significance of understanding spatial regulation within AH liver tissue, and further facilitated the development of therapeutic strategies at high resolution.

Proteomics

Patient-specific modeling identifies metabolic interventions for reversing glucose use reprogramming in alcohol-associated hepatitis.

Alcoholic hepatitis (AH) is an acute form of alcohol-associated liver disease with very few treatment options. Recent studies highlighted liver metabolic reprogramming in AH as an indicator of severity. We aim at identifying new intervention points to reverse liver metabolic dysregulation across varying degrees of AH. We develop 89 personalized genome-scale metabolic models by integrating a generic human cellular metabolic model with liver transcriptomics data from AH patients with varying disease severity and healthy controls. We grade the AH patients based on the model-predicted level of glycolysis reprogramming and validate the results using published metabolomics data. We test in silico gene knockdown interventions to reverse the aberrant metabolic reprogramming in AH. Knockdown of two glycolytic genes, Hkdc1 and Pkm, significantly rebalance the metabolic fluxes toward a healthy liver metabolic phenotype. We use machine learning on the glycolysis fluxes to develop a quantitative glucose use reprogramming score, which correlates with AH severity and patient-specific responses to in silico gene knockdown interventions. The score was independently validated using a published AH liver transcriptomics dataset. We propose a cellular metabolism-based therapy targeting Hkdc1 and Pkm in the glycolysis pathway as a potential treatment for reversing the aberrant glucose metabolism in AH.

Humans

Global Changes in Gene Expression and Splicing in Alcoholic Liver Disease.

Alcohol use disorder is a widespread illness commonly leading to alcoholic liver disease (ALD) and cirrhosis with an increased incidence of hepatocellular carcinoma (HCC), but the mechanisms of alcohol-related oncogenesis in the liver are incompletely understood. We tested the hypothesis that ALD predisposes to HCC via dysregulation of splicing. RNA sequencing was performed on liver biopsies from patients with different stages of ALD: early alcoholic steatohepatitis (eASH), non-severe alcoholic hepatitis (nsAH), and severe alcoholic hepatitis (sAH); furthermore, explants were collected from patients who underwent liver transplantation due to sAH (exAH). We found that alcohol caused widespread changes in transcriptome in all stages of ALD: among ~ 58,000 analyzed genomic features, ~ 4,900 were altered in eASH, ~ 9,100 - in nsAH, 14,100 - in sAH, and ~ 14,300 - in exAH. We observed thousands of missplicing events in all hepatic conditions, with mutually exclusive exons (MEE) being the most common event and exon skipping (ES) - second most common event. Analysis of ~ 600,000 exons revealed that ALD is associated with a genome-wide effect on exon expression, with ~ 50,000 exons being differentially expressed in eASH, ~ 130,000 - in nsAH, ~ 150,000 - in sAH, and ~ 120,000 - in exAH. To determine whether alcohol directly perturbs splicing, we subjected rats to alcohol vapor for 7 weeks and found that the expression of multiple snRNAs was drastically decreased, while expression of splicing factors was not affected. Screening of oncogenes and tumor suppressors, commonly involved in HCC pathogenesis, revealed that ALD affected the hepatic expression and/or splicing of most of these cancer-related genes. In summary, it appears that alcohol causes profound genome-wide changes in gene expression and splicing in the liver, likely via affecting the spliceosome. This results in altered expression and missplicing of key oncogenes and tumor suppressors involved in HCC, suggesting a novel mechanism of oncogenesis in the liver of patients with ALD.

alcohol use disorder