Association of BCAT2 and BCKDH polymorphisms with clinical, anthropometric and biochemical parameters in young adults

Branched-chain amino acid metabolism: Pathophysiological mechanism and therapeutic intervention in metabolic diseases

Branched-chain amino acids (BCAAs), including leucine, isoleucine, and valine, are essential for maintaining physiological functions and metabolic homeostasis. However, chronic elevation of BCAAs causes metabolic diseases such as obesity, type 2 diabetes (T2D), and metabolic-associated fatty liver disease (MAFLD). Adipose tissue, skeletal muscle, and the liver are the three major metabolic tissues not only responsible for controlling glucose, lipid, and energy balance but also for maintaining BCAA homeostasis. Under obese and diabetic conditions, different pathogenic factors like pro-inflammatory cytokines, lipotoxicity, and reduction of adiponectin and peroxisome proliferator-activated receptors γ (PPARγ) disrupt BCAA metabolism, leading to excessive accumulation of BCAAs and their downstream metabolites in metabolic tissues and circulation. Mechanistically, BCAAs and/or their downstream metabolites, such as branched-chain ketoacids (BCKAs) and 3-hydroxyisobutyrate (3-HIB), impair insulin signaling, inhibit adipogenesis, induce inflammatory responses, and cause lipotoxicity in the metabolic tissues, resulting in multiple metabolic disorders. In this review, we summarize the latest studies on the metabolic regulation of BCAA homeostasis by the three major metabolic tissues-adipose tissue, skeletal muscle, and liver-and how dysregulated BCAA metabolism affects glucose, lipid, and energy balance in these active metabolic tissues. We also summarize therapeutic approaches to restore normal BCAA metabolism as a treatment for metabolic diseases.

Multi-omics analysis identifies BCAT2 as a potential pan-cancer biomarker for tumor progression and immune microenvironment modulation

Branched-chain amino acid transaminase 2 (BCAT2) encodes a crucial protein involved in the initial catalysis of branched-chain amino acid (BCAA) catabolism, with emerging evidence suggesting its association with tumor progression. This study explores BCAT2 in a pan-cancer multi-omics context and evaluates its prognostic significance. We utilized a multi-database approach, analyzing cBioPortal for genetic alterations, RNA-Seq data from TCGA and GTEx for expression patterns, and RSEM for transcript analysis. Protein expression and interaction networks were assessed using the Human Protein Atlas, UniProt, and STRING. Prognostic value was determined through Cox regression analysis of TCGA clinical survival data, while immune cell infiltration across various cancers was examined using TCGA data and the TIMER2 platform. Our results revealed that BCAT2 alterations are primarily amplifications and is upregulated in various tumors, correlating with poor survival rates in several tumor types, including GBMLGG, LGG, and UVM. Elevated BCAT2 protein levels were common in pan-cancer, interacting with a range of metabolic enzymes. Additionally, BCAT2 expression significantly influenced CD4+ T cells, CD8+ T cells, and Treg cells infiltration, with varied correlations across cancer types. These findings indicate BCAT2 as a potential biomarker for cancer diagnosis and therapy, potentially regulating key metabolic and immune factors to mediate tumor progression and the microenvironment.

Genetic risk score for insulin resistance based on gene variants associated to amino acid metabolism in young adults

Circulating concentration of arginine, alanine, aspartate, isoleucine, leucine, phenylalanine, proline, tyrosine, taurine and valine are increased in subjects with insulin resistance, which could in part be attributed to the presence of single nucleotide polymorphisms (SNPs) within genes associated with amino acid metabolism. Thus, the aim of this work was to develop a Genetic Risk Score (GRS) for insulin resistance in young adults based on SNPs present in genes related to amino acid metabolism. We performed a cross-sectional study that included 452 subjects over 18 years of age. Anthropometric, clinical, and biochemical parameters were assessed including measurement of serum amino acids by high performance liquid chromatography. Eighteen SNPs were genotyped by allelic discrimination. Of these, ten were found to be in Hardy-Weinberg equilibrium, and only four were used to construct the GRS through multiple linear regression modeling. The GRS was calculated using the number of risk alleles of the SNPs in HGD, PRODH, DLD and SLC7A9 genes. Subjects with high GRS (≥ 0.836) had higher levels of glucose, insulin, homeostatic model assessment- insulin resistance (HOMA-IR), total cholesterol and triglycerides, and lower levels of arginine than subjects with low GRS (p < 0.05). The application of a GRS based on variants within genes associated to amino acid metabolism may be useful for the early identification of subjects at increased risk of insulin resistance.

Protein restriction and branched-chain amino acid restriction promote geroprotective shifts in metabolism

The proportion of humans suffering from age‐related diseases is increasing around the world, and creative solutions are needed to promote healthy longevity. Recent work has clearly shown that a calorie is not just a calorie—and that low protein diets are associated with reduced mortality in humans and promote metabolic health and extended lifespan in rodents. Many of the benefits of protein restriction on metabolism and aging are the result of decreased consumption of the three branched‐chain amino acids (BCAAs), leucine, isoleucine, and valine. Here, we discuss the emerging evidence that BCAAs are critical modulators of healthy metabolism and longevity in rodents and humans, as well as the physiological and molecular mechanisms that may drive the benefits of BCAA restriction. Our results illustrate that protein quality—the specific composition of dietary protein—may be a previously unappreciated driver of metabolic dysfunction and that reducing dietary BCAAs may be a promising new approach to delay and prevent diseases of aging.