Biology subjects

Kasumov, T.

Publications and source records attributed to Kasumov, T..

3 recordsLinked to original sources

bioRxiv2026

In Vivo Quantification of Histone Acetylation Turnover and Acetyl-CoA Sources Using 2H2O Metabolic Labeling and High-Resolution Mass Spectrometry.

Dysregulated histone acetylation links cellular metabolism to gene expression, but measuring its in vivo turnover remains technically challenging. Here, we introduce a 2H2O-based metabolic labeling method coupled with high-resolution Orbitrap mass spectrometry to quantify in vivo histone acetylation dynamics. The approach leverages differing deuterium incorporation rates between fast-labeling acetyl groups and slow-labeling peptide backbones. A two-tier analytical workflow uses full-scan mass spectrometry for mono-acetylated peptides, combined with parallel reaction monitoring (PRM) to resolve site-specific turnover and stoichiometry. Furthermore, monitoring acetyl-group plateau 2H enrichment enables the evaluation of specific substrate contributions to the acetyl-CoA pool supporting histone acetylation. To demonstrate biological utility, we applied this approach to mice maintained on a high-carbohydrate diet or subjected to 48-h fasting to assess nutrient-dependent histone acetylation dynamics. Acetyl-group labeling reflected the metabolic origin of acetyl-CoA, showing greater 2H enrichment in the fed state and reduced enrichment during fasting due to increased utilization of unlabeled fatty acid-derived acetyl-CoA. Fasting accelerated acetylation turnover across multiple histone sites and reduced overall acetylation stoichiometry. Quantitative tracing revealed that fatty acid oxidation becomes an important contributor to histone acetylation during fasting, whereas glucose remains the predominant source of nucleo-cytosolic acetyl-CoA (supplying > 60% of acetylation used carbon). This approach enables simultaneous in vivo assessment of histone acetylation turnover, site occupancy, and acetyl-CoA substrate utilization, offering a robust platform to investigate metabolic-epigenetic crosstalk in health and disease.

biochemistry↗

bioRxiv2026

Integrated multi-omics reveals adaptive anti-oxidant remodeling in early alcohol-associated liver disease

Alcohol-associated liver disease (ALD) is a leading cause of liver-related morbidity and mortality. Although various omics approaches have revealed early metabolic alterations, individual datasets provide limited mechanistic insight. Here, we integrated RNA sequencing with mass spectrometry-based analyses to quantify gene expression, protein abundance, proteome and acetylome dynamics, and metabolic fluxes in livers of alcohol-fed mice. This multi-layered approach revealed extensive metabolic rewiring characterized by suppressed mitochondrial energy metabolism and compensatory upregulation of glutathione (GSH) production, utilization, and recycling, establishing a high-flux antioxidant network. These changes were coupled to epigenetic histone H3 remodeling, marked by increased permissive acetylation and decreased suppressive methylation, linking alcohol-induced metabolic and redox alterations to chromatin reprogramming. ChEA-based in silico upstream transcription factor analysis, identified hepatocyte nuclear factor 4 (HNF4) and nuclear factor erythroid 2-related factor 2 (NRF2) as key regulatory nodes. Alcohol exposure was associated with a modest HNF4 suppression alongside increased expression of NRF2, indicating a shift from HNF4-driven metabolic programs toward NRF2-mediated antioxidant responses. Despite acetylation-associated impairment of mitochondrial proteins, GSH-related enzymes were preserved, supporting a protective, high-turnover antioxidant response that limits early oxidative stress and defines an adaptive state maintaining redox homeostasis while potentially predisposing to ALD progression.

biochemistry↗

bioRxiv2026

Loss of Propionyl-CoA Carboxylase Reprograms Hepatic Metabolism by Suppressing Mitochondrial Pyruvate Carboxylation and Fatty Acid Oxidation

Propionic acidemia (PA) is an inborn error of metabolism caused by propionyl-CoA carboxylase (PCC) deficiency due to mutations in either PCCA or PCCB. Without proper management, the disease is associated with high mortality. Even with dietary restriction, patients often develop complications later in life, and the underlying pathological mechanisms remain poorly understood. The liver is the primary organ responsible for propionyl-CoA metabolism, yet the metabolic alterations induced by PCC deficiency in the liver have not been systematically investigated. In this study, we used a hepatocyte model of PA-- PCCAnull-HepG2 cells--to comprehensively examine metabolic alterations using stable isotope-based metabolic flux analysis. The PCCA knockout recapitulated key metabolic features of PA in HepG2 cells. Furthermore, PCCA deficiency reduced mitochondrial fatty acid oxidation while increasing glucose oxidation through pyruvate dehydrogenase. In contrast, pyruvate anaplerosis via pyruvate carboxylase was markedly reduced in PCCA knockout cells. This reduction in anaplerotic flux impaired the capacity for gluconeogenesis and lipid synthesis, consistent with observations from in vivo studies in Pcca-/- (A138T) mice. Additionally, branched-chain keto acid catabolism was reduced in PCCA knockout HepG2 cells. Threonine showed minimal metabolic contribution in this model, further supporting the role of propionate as a major source of propionyl-CoA production. Collectively, these findings highlight the metabolic vulnerabilities associated with PCC deficiency and underscore the increased risk of prolonged fasting in patients with PA, particularly those with severe disease.

genetics↗