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Nutrient competition between tumor and immune cells is a hallmark of the glioblastoma (GBM) microenvironment, yet the mechanisms underlying amino acid metabolic reprogramming and immune evasion remain incompletely understood. Here, we demonstrate that GBM cells outcompete NK cells for branched-chain amino acid (BCAA), leading to BCAA depletion, suppression of NK and CD8 Show less

Testosterone production by testicular Leydig cells (steroidogenesis) is vital to male fertility and overall male health. Information about how nutrition influences Leydig cell steroidogenesis is lacking. Branched chain amino acids (BCAAs - leucine, isoleucine, and valine) are essential amino acids and important regulators of protein synthesis and energy production. Circulating and tissue BCAA levels are tightly regulated by the enzyme branched chain a-keto acid dehydrogenase kinase (BCKDK), which inhibits their catabolism. This work explored how BCAAs, and especially leucine, modulate male fertility and testosterone production. In a mutant mouse model of Bckdk, breeding analysis showed reduced male fertility and circulating testosterone. Further, morphological evaluation demonstrated testicular and epididymal abnormalities consistent with abnormal testicular androgen signaling. Fertility was partially rescued by feeding a high protein diet while circulating testosterone was not. In wild type testes, Leydig cells were the primary cell type to express BCKDK. Leveraging a primary interstitial cell culture, cell survival and apoptosis analyses demonstrated Leydig cells are highly sensitive to leucine deprivation and this sensitivity is enhanced under steroidogenesis stimulating conditions. Lastly, using the same primary cell culture system, testosterone production was shown to be lost under leucine deprivation. In total, this work demonstrates Leydig cells are uniquely sensitive to BCAA status under steroidogenesis stimulation and that regulated BCAA catabolism may be important for optimal male fertility. Show less

Metabolic reprogramming of Branched-chain amino acids (BCAAs)-leucine, isoleucine, and valine-has emerged as a constitutive feature of cancer, extending far beyond their canonical roles in protein synthesis and energy provision. In malignancy, these essential amino acids function as pivotal signaling mediators and epigenetic modulators, thereby propelling tumor progression, facilitating immune evasion, and conferring resistance to therapeutic agents. This review delineates how cancer cells subvert branched-chain amino acid metabolism to fuel anabolic processes, activate oncogenic signaling cascades including mTOR and PI3K/AKT, and remodel the tumor microenvironment. A framework is presented to categorize the differential reliance of various cancers on key catabolic enzymes-BCAT1, BCAT2 and BCKDK-underscoring their therapeutic vulnerability. The paradoxical role of BCAAs in modulating anti-tumor immunity is examined alongside the potential of dietary modulation and the development of pharmacological inhibitors targeting this pathway. Concluding perspectives highlight the trajectory for translating these insights into precision oncology, advocating for biomarker-guided and context-specific therapeutic strategies. Show less

The cardiac lymphatic system plays a crucial role in maintaining myocardial homeostasis by regulating fluid equilibrium, immune surveillance, and metabolite clearance. This review highlights recent advances in understanding its development, molecular regulation, dual roles in pathophysiology, and translational potential. Cardiac lymphatic endothelial cells (LECs) develop from diverse progenitors, including venous endothelium and Isl1⁺ precursors from the second heart field (SHF) under sex-specific molecular guidance. Functionally, the Vascular endothelial growth factor C (VEGFC)/Vascular endothelial growth factor receptor 3 (VEGFR3) signaling is paramount, modulated contextually by factors like adrenomedullin and branched-chain ketoacid dehydrogenase kinase (BCKDK). Lymphatic dysfunction impacts cardiovascular disease paradoxically. While protective in the acute phase of myocardial infarction by limiting inflammatory edema, it becomes detrimental in chronic hypertension and calcific aortic valve disease (CAVD). Single-cell transcriptomics (scRNA-seq) resolve this contradiction by revealing distinct functional LEC subpopulations: Transforming growth factor-beta 1 (TGF-β1)⁺/Interleukin 10 (IL-10)⁺ LECs promote post-infarction repair, while Reelin⁺/C-C motif chemokine ligand 21 (CCL21)⁺ LECs promote osteogenesis and valve calcification in CAVD. Emerging strategies focus on cardiac-targeted nanotherapeutics, epigenetic and metabolic LEC modulation, and sex-specific dosing. Critical unresolved questions involve autonomic nerve-lymphatic integration and lineage-specific epigenetic memory. Advancing precision lymphatic imaging, genotype-informed clinical trials, and spatiotemporal control of LEC phenotypes is critical for therapeutic translation. Deeper understanding promises novel treatments for heart failure, inflammatory cardiomyopathies, and fibrosis. Show less

Metabolic diseases such as obesity, type 2 diabetes mellitus (T2DM), dyslipidaemia, and metabolic dysfunction-associated steatotic liver disease (MASLD) are increasingly recognised as chronic inflammatory conditions driven in part by innate immune dysregulation. Among the metabolic factors implicated in this process, branched-chain amino acids (BCAAs) have emerged as key regulators linking nutrient sensing to immune cell function. Circulating BCAA concentrations are consistently elevated in these metabolic diseases. However, experimental and clinical studies also show that BCAA supplementation can improve metabolic and immune outcomes in specific contexts, revealing a paradoxical relationship between BCAA metabolism and inflammation. This narrative review examines how dysregulated BCAA metabolism and accumulation of branched-chain keto acids (BCKAs) shape the functional programming of innate immune cells across these conditions, including monocytes/macrophages, granulocytes, dendritic cells, and natural killer cells. Evidence indicates that the immunometabolic effects of BCAAs depend not solely on circulating concentrations but on the efficiency of their intracellular catabolism. When BCAA oxidation is preserved, these amino acids support mitochondrial metabolism and immune competence. Conversely, impaired catabolism leads to the accumulation of branched chain ketoacids, which activate inflammatory pathways and contribute to metabolic dysfunction. Resolving this paradox requires the need of targeting catabolic flux restoration rather than simple BCAA restriction or supplementation, and requires stratifying patients by enzymatic capacity, BCAA/BCKA ratios, and disease stage. Pharmacological modulators, including BCKDK inhibitors and BCAT1-targeted agents, show promise in simultaneously addressing metabolic and immune dysregulation. Show less

Pancreatic cancer (PC) is a common gastrointestinal malignancy whose initiation and progression may be closely linked to the gut microbiota. Previous research indicates that Scutellaria barbata D. Don and Scleromitrion diffusum (Willd.) R.J. Wang (SB-SD) exhibit diverse biological activities, such as anti-inflammatory, antioxidant, and antitumor effects, though their precise regulatory mechanisms are not fully elucidated. Here, we treated PC cells with SB-SD to assess its impact on cell viability, apoptosis, migration, and cell cycle progression, while Western blotting analyzed the expression of HSP90AA1, MAPK3, p53, CDK1, and p21. We also established a pancreatic cancer xenograft model in nude mice to evaluate the in vivo inhibitory effect of SB-SD on tumor growth. Furthermore, we employed metagenomic sequencing, untargeted metabolomics, and quantitative proteomics to comprehensively profile changes in the gut microbiota, serum metabolites, and differentially expressed proteins, with Western blotting subsequently validating BCKDK, GATM and p53 expression. The results show that SB-SD significantly inhibited PC cell proliferation, promoted apoptosis, and induced S/G2 phase cell cycle arrest, potentially via modulation of the HSP90AA1/MAPK3 signaling pathway. Measurements of tumor volume and weight, complemented by histopathological analysis, confirmed that SB-SD effectively suppressed the growth of PANC-1 xenograft tumors. Integrated multi-omics analyses suggest that the antitumor effects of SB-SD may involve the modulation of key gut microbes like Bacteroides caccae and Lactobacillus, the promotion of choline metabolism, and the regulation of BCKDK and GATM. Together, these findings not only corroborate the direct antitumor activity of SB-SD against pancreatic cancer but also offer novel mechanistic insights by constructing a microbiota-metabolite-protein interaction network. Show less

Branched-chain α-amino acids (BCAAs) support protein synthesis and their oxidation is restrained by branched-chain α-keto acid dehydrogenase kinase (BCKDK). We previously observed that in the brains of Bckdk knockout (KO) mice, BCAAs fall while glutamate is preserved and other amino acids rise. We asked why this profile emerges and how it affects skeletal muscle versus brain during nutrient stress. Motor behavior, protein synthesis and nutrient signaling were compared in the skeletal muscle and brains of wildtype (WT) and Bckdk KO male mice. In addition, nitrogen delivery into brain from BCAAs was assessed using stable isotope tracing and mass spectrometry imaging. Bckdk KO showed normal grip strength but poor beam traversal and reduced wheel running during protein restriction. In skeletal muscle, leucine or protein-feeding stimulated and fasting suppressed mechanistic target of rapamycin complex 1 (mTORC1) signaling in both genotypes. Fasting reduced muscle protein synthesis in both strains without activating the integrated-stress response (ISR). In contrast, Bckdk KO brains exhibited ISR activation during fasting, and up-regulation of Atf4 and its target genes, including Slc7a5 mRNA. Tracer studies revealed lower serum [ Show less

Mutations in the branched-chain keto-acid dehydrogenase kinase gene (BCKDK), leading to low plasma branched-chain amino acids (BCAAs) levels, have been reported as a contributor to comorbid intellectual disability, autism, epilepsy, and neurodevelopmental delay (NDD). Due to the rarity of knowledge about these mutations, the current case series aims to introduce four confirmed cases. This case series study analyzed children from a neurometabolic clinic. Social and adaptive functions were assessed using the vineland social maturity scale (VSMS). Whole exome sequencing (WES) identified genetic variants filtered using population databases. Candidate variants were confirmed through Sanger sequencing and interpreted based on ACMG guidelines. Four children of unrelated consanguineous families suffering from global NDD and autism were referred to our center. Neuroimaging assessments revealed negligible findings; thus, metabolic tests were sent, in which BCAAs were lower than normal limits. Therefore, genetic testing was done, and genetic variants compatible with BCKDK deficiency were detected. By initiating a BCAAs-rich regimen, the patients had significant improvements in psychomotor and speech development. The diagnosis of BCKDK deficiency should be suspected in patients with NDD and autism, and BCAA supplementation should be initiated as soon as diagnosis confirmation to prevent irreversible brain damage. The results emphasize that early diagnosis and dietary intervention by regulating plasma BCAA levels lead to the prevention of irreversible neurodevelopmental implications. Show less

The protein branched-chain ketoacid dehydrogenase kinase (BCKDK), which regulates the metabolism of branched-chain amino acids, has recently been implicated in tumor progression. However, the role of BCKDK in lung cancer remains largely unexplored. In this study, we explored the mechanisms by which BCKDK influences lung cancer progression and contributes to drug resistance. By integrating single-cell RNA and bulk RNA sequencing data from lung cancer patients, we identified BCKDK as a novel gene related to malignant epithelial cells, involved in tumor initiation and associated with poor patient prognosis. Subsequently, through a series of molecular biology experiments, we demonstrated that BCKDK promotes aerobic glycolysis, Trametinib resistance, and tumor progression in lung cancer by upregulating MYC transcription. Mechanistically, BCKDK interacts with BCLAF1 to promote its phosphorylation at the serine 285 site. This modification facilitates BCLAF1 binding to the MYC promoter, thereby enhancing MYC transcription. Subsequently, elevated MYC levels upregulate hexokinase 2, promoting aerobic glycolysis and lung cancer progression. In addition, the elevated glycolysis product, lactate, promotes Trametinib resistance by upregulating the ABC transporters. Taken together, our data identify BCKDK as a novel regulator of aerobic glycolysis that promotes lung cancer progression and Trametinib resistance through the BCKDK/BCLAF1/MYC/HK2 axis. Targeting BCKDK in combination with Trametinib may offer a promising treatment for lung cancer. Graphical representation of the BCKDK/BCLAF1/MYC/HK2 axis and its role in Trametinib resistance and lung cancer progression. Created with BioRender.com. Show less

By integrating single-cell and bulk RNA-sequencing data for esophageal cancer (ESCA), we developed and validated a seven-macrophage-gene prognostic signature (FCN1, SCARB2, ATF5, PHLDA2, GLIPR1, CHORDC1, and BCKDK). This signature effectively stratified patients into high- and low-risk groups with significantly different overall survival, achieving area under the curve (AUC) values greater than 0.7 for 1-, 2-, and 3-year survival prediction. A high-risk status correlated with an immunosuppressive tumor microenvironment, characterized by lower infiltration of B cells and CD8 + T cells, and was associated with reduced sensitivity to multiple chemotherapeutic agents, including Cisplatin and 5-Fluorouracil. Conversely, a low-risk status was linked to greater immune cell infiltration and higher predicted chemosensitivity. At the single-cell level, pseudotime analysis revealed that macrophage maturation significantly correlated with a decreasing risk score, suggesting that mature macrophages may contribute to a favorable prognosis. Furthermore, cell communication analysis identified high-risk macrophages as dominant drivers of a pro-tumorigenic microenvironment via signaling pathways, such as SPP1 and complement. In conclusion, this seven-gene signature is a robust prognostic biomarker that offers a new strategy for personalized risk assessment and treatment selection in ESCA. The online version contains supplementary material available at 10.1007/s13205-025-04452-w. Show less

Patients with metabolic syndrome and heart failure (HF) often have accompanying kidney dysfunction, which was recently defined as cardiovascular-kidney-metabolic (CKM) syndrome. Prior metabolomics profiling of metabolic syndrome patients identified a plasma branched chain amino acid (BCAA) signature, and BCAAs themselves are elevated in the myocardium of patients with HF, potentially due to a defect in BCAA catabolic breakdown. The rate limiting step of BCAA catabolism is the decarboxylation by the enzyme branched chain ketoacid dehydrogenase (BCKDH), which is negatively regulated by BCKDH kinase (BCKDK or BDK), and BDK inhibitors improve metabolism and heart failure preclinically. Here, using two pre-clinical CKM models, the hyperphagic ZSF1 obese rat and the uninephrectomized SDT fatty rat with high salt drinking water, we applied unbiased proteomic, transcriptomic and metabolomic profiling to assess overall kidney gene expression and mitochondrial function. We show that BCAA catabolic impairment is associated with and may be causal to CKM and demonstrated impairment in BCAA catabolism within ZSF1 obese rat kidneys. In both CKM animal models, treatment with the BDK inhibitor BT2 improved urine protein content, kidney hypertrophy, and kidney pathology. Furthermore, coadministration of BT2 and the sodium-glucose cotransporter-2 inhibitor empagliflozin demonstrated additive effects to improve kidney parameters, kidney gene expression signatures, and kidney mitochondrial density and function. Our study suggests that in addition to its previously reported beneficial effects on metabolism and cardiac function, BDK inhibition may also improve kidney health and therefore could represent a new therapeutic avenue for CKM. Show less

Rubia cordifolia L. (RCL) is a widely used medicinal with a long history. It exhibits anti-inflammatory and antioxidant properties and prevents apoptosis. While there is growing evidence that exhausted exercise (EE) might cause cardiac damage, RCL has been shown to provide cardioprotective effects. The effects and mechanisms of RCL on exercise-induced myocardial injury remain unclear. In this study, we tested the RCL extract using a rat model of exhausted swimming. We evaluated the therapeutic effect of RCL on exercise-induced myocardial damage using PCR, ELISA, hematoxylin-eosin (H&E) staining, DHE staining, and other methods. UPLC-Q-TOF-MS was employed to identify the components of the RCL extract and its blood-entry components, and network pharmacology was constructed. LC-MS was utilized to investigate left ventricular metabolomics. These two approaches were combined to predict the possible metabolic pathways regulated by RCL. Finally, the targets of the metabolic pathway were verified using molecular docking and western blot analysis. The findings suggest that rubioncolin B, 4-hydroxy-2-carbexyanthraquinone, and 9-Oxo-9H-xanthene-4-carboxylic acid may be the primary active compounds of RCL. RCL promotes the degradation pathway of branched-chain amino acids (BCAA), including valine, leucine, and isoleucine, regulates the proteins BCAT2 and BCKDK, reduces pathological injuries, inflammation, oxidative stress, and collagen deposition, and mitigates the effects of exhaustion-induced myocardial injuries by influencing the key target AKR1C1 and the metabolite L-Valine. This study provides a foundation for the development of RCL as a sports supplement to alleviate EE-induced myocardial injury. Show less

Pathological cardiac hypertrophy is an independent risk factor for heart failure (HF). Early identification and timely treatment are crucial for significantly delaying the progression of HF. Targeted amino acid metabolomics and RNA sequencing (RNA-seq) were combined to explore the underlying mechanism. In vitro, H9c2 cells were stimulated with angiotensin II (Ang II) or were incubated with extra valine after Ang II stimulation. The branched chain alpha-ketoate dehydrogenase kinase (Bckdk) inhibitor 3,6-dichlorobenzo[b]thiophene-2-carboxylic acid (BT2) and rapamycin were utilized to confirm the role of the mammalian target of rapamycin complex 1 (mTORC1) signaling pathway in this process. A significant accumulation of valine was detected within hypertrophic hearts from spontaneously hypertensive rats (SHR). When branched chain amino acid (BCAA) degradation was increased by BT2, the most pronounced decrease was observed in the valine level (Δ = 0.185 μmol/g, p < 0.001), and cardiac hypertrophy was ameliorated. The role of imbalanced mitochondrial quality control (MQC), including the suppression of mitophagy and excessive mitochondrial fission, was revealed in myocardial hypertrophy. In vitro, high concentrations of valine exacerbated cardiomyocyte hypertrophy stimulated by Any II, resulting in the accumulation of impaired mitochondria and respiratory chain dysfunction. BT2, rapamycin, and mitochondrial division inhibitor 1 (Mdivi-1) all ameliorated MQC imbalance, mitochondrial damage and oxidative stress in hypertensive models with high valine concentration. Valine exacerbated pathological cardiac hypertrophy by causing a MQC imbalance, probably as an early biomarker for cardiac hypertrophy under chronic hypertension. Show less

Kidney tubular cell injury is largely responsible for the pathophysiological features of diabetic kidney disease (DKD). Increased leucine levels in individuals with DKD have been associated with the progression of diabetes to end-stage renal failure, yet a comprehensive understanding of leucine metabolism in kidney tubules during the progression of DKD is lacking. Human kidney biopsies and mouse models were used to assess leucine metabolism during DKD progression. Enhancement of leucine degradation was achieved through genetic ablation or pharmacological inhibition of branched-chain ketoacid dehydrogenase kinase (BCKDK). Cultured kidney tubular epithelial cells were used to analyse the underlying cellular mechanisms. The association of urinary leucine with progression of DKD was determined in individuals with diabetes. Measurements of metabolites and enzymes suggested defective leucine degradation and increased BCKDK expression in kidney tubules during DKD progression. Enhancement of leucine degradation relieved glucose-induced metabolic remodelling in tubular cells and mitigated DKD in mouse models. Accumulation of leucine stimulated metabolic remodelling via the mTOR signalling pathway; this was relieved by blocking leucine uptake or enhancing its degradation. Restricting dietary leucine significantly decreased albuminuria, kidney hypertrophy and lipid accumulation in mouse models of diabetes. Additionally, we observed that rapid decline in kidney function correlated with a higher urinary leucine-to-creatinine ratio in both female and male individuals with diabetes. In summary, we identify defective leucine degradation in renal tubules of diabetic individuals and propose leucine as a causative factor for DKD, highlighting its potential as a therapeutic target for further investigation. The transcriptomic data supporting the findings of this study are openly available at the National Center for Biotechnology Information Sequence ReadArchive (SRA) ( https://www.ncbi.nlm.nih.gov/sra , identifiers: PRJNA1180888 and PRJNA1180923). The metabolomics data associated with the manuscript are available in the ESM. Show less

Sodium-glucose cotransporter 2 inhibitors (SGLT2i) confer cardio-renal protection, and recent work implicates enhanced branched-chain amino acid (BCAA) catabolism as a potential mechanism in the heart. Whether SGLT2i also promotes renal BCAA catabolism is largely unknown. We hypothesized that SGLT2i enhances renal BCAA catabolism independently of glycemic effects. We conducted a prospective, single-center, open-label, nonrandomized, controlled clinical study in patients with type 2 diabetes stably treated with insulin, who were assigned to dapagliflozin (5 mg/day with dose-reduced insulin; n=8/9 completed) or insulin dose-up (n=5/8 completed). At 12 weeks, changes in urinary and plasma metabolites and short-chain acylcarnitines related to BCAA catabolism were quantified. To explore mechanisms, 10-week-old db/db mice received luseogliflozin (10 mg/kg/day, p.o.) or insulin glargine (10 U/day, s.c.) for 4 weeks; renal histology, mRNA and protein expression of key enzymes involved in BCAA catabolism, including branched-chain aminotransferase 2 (BCAT2), branched-chain ketoacid dehydrogenase (BCKDH), and BCKD kinase (BCKDK), were assessed. Dapagliflozin treatment induced greater increases in urinary excretion of three BCAA-derived metabolites-3-hydroxypropionic acid, C5-OH carnitine, and 3-hydroxybutyric acid-compared with insulin at comparable glycemic levels. In contrast, C4 carnitine (an earlier metabolite in valine catabolism) rose more with insulin. No corresponding between-group differences were detected in plasma metabolites. In db/db mice, luseogliflozin attenuated glomerular mesangial expansion and tubular epithelial atrophy, and reduced Col1a1 mRNA and TGF-β1 protein, compared with glargine at comparable glycemic levels. Luseogliflozin decreased the phosphorylated (inactive) form of the BCKDH E1α subunit (p-BCKDHA/BCKDHA) and lowered BCKDK protein. mRNA expression of amino acid transporters and BCAT2 expression was unchanged. Across complementary human and mouse studies, SGLT2 inhibition was suggested to enhance renal BCAA catabolism compared with insulin at comparable glycemic levels. In humans, increases in urinary BCAA-derived downstream metabolites without corresponding changes in plasma support a kidney-localized metabolic effect. In mice, SGLT2 inhibitor improved renal histopathology, and reduced phosphorylation-mediated inactivation of BCKDH. These findings provide mechanistic, translational evidence that SGLT2i modulate BCAA flux independently of glucose lowering, suggesting BCAA catabolism as a therapeutic axis in diabetic kidney disease. https://rctportal.mhlw.go.jp/en/detail?trial_id=UMIN000052955, identifier UMIN000052955. Show less

Branched-chain amino acid (BCAA) metabolism is perturbed in patients with pancreatic cancer, but the contribution of systemic or pancreas-intrinsic BCAA catabolism to pancreatic carcinogenesis is unclear. We show here that pancreas-specific loss of DBT, the E2 subunit of the branched-chain keto-acid dehydrogenase (BCKDH) complex required for BCAA oxidation, strikingly exacerbates premalignant pancreatic intraepithelial neoplasia (PanIN) lesions in KC ( Show less

Metabolic reprogramming involving branched-chain amino acids (BCAAs)-leucine, isoleucine, and valine-is increasingly recognized as pivotal in cancer progression, metastasis, and immune modulation. This review comprehensively explores how cancer cells rewire BCAA metabolism to enhance proliferation, survival, and therapy resistance. Tumors manipulate BCAA uptake and catabolism via high expression of transporters like L-type amino acid transporter 1 (LAT1) and enzymes including branched chain amino acid transaminase 1(BCAT1), branched chain amino acid transaminase 2 (BCAT2), branched-chain alpha-keto acid dehydrogenase (BCKDH), and branched chain alpha-keto acid dehydrogenase kinase (BCKDK). These alterations sustain energy production, biosynthesis, redox homeostasis, and oncogenic signaling (especially mammalian target of rapamycin complex 1 [mTORC1]). Crucially, tumor-driven BCAA depletion also shapes an immunosuppressive microenvironment, impairing anti-tumor immunity by limiting essential nutrients for T cells and natural killer (NK) cells. Innovative therapeutic strategies targeting BCAA pathways-ranging from selective small-molecule inhibitors (e.g., LAT1 and BCAT1/2) to dietary modulation-have shown promising preclinical and early clinical efficacy, highlighting their potential to exploit metabolic vulnerabilities in cancer cells while bolstering immune responses. By integrating multi-omics data and precision targeting approaches, this review underscores the translational significance of BCAA metabolic reprogramming, positioning it as a novel frontier in cancer treatment. Show less

Branched-chain amino acids (BCAAs), including valine, leucine and isoleucine, are essential nutrient signals that influence mammalian animal metabolism. Many enzymes are involved in the metabolism of BCAAs, such as branched-chain amino acid transaminases (BCATs), branched-chain α-keto acid dehydrogenase (BCKDH), and BCKDH kinase (BCKDK). The aberrant expression of enzymes involved in BCAA metabolism and an imbalance in BCAA amino acid intake can lead to disordered metabolism. Aberrant BCAA metabolism can lead to several diseases, such as human ovarian disease, including ovarian cancer (OC), polycystic ovary syndrome (PCOS), and premature ovarian failure (POF), which are common gynaecological diseases. The overexpression of BCATs is found in OC, which promotes BCAA catalysis to provide a large amount of energy for tumorigenesis. However, BCKDK is overexpressed in epithelial ovarian cancer (EOC), which promotes proliferation and migration via MEK-ERK. In addition, several studies have reported that high levels of BCAAs are increased in the plasma of PCOS and POF patients. This review focuses on the role of BCAA metabolism and potential management methods for OC, PCOS and POF. Show less

The maternal-to-zygotic transition (MZT) is a reprograming process encompassing zygotic genome activation (ZGA) and the clearance of maternally-provided mRNAs. While some factors regulating MZT have been identified, there are thousands of maternal RNAs whose function has not been ascribed yet. Here, we have performed a proof-of-principle CRISPR-RfxCas13d maternal screen, in which we targeted mRNAs encoding kinases and phosphatases or proteins regulating them in zebrafish. This screen identified branched-chain ketoacid dehydrogenase kinase, Bckdk, as a novel post-translational regulator of MZT. Bckdk mRNA knockdown caused epiboly defects, ZGA deregulation, H3K27ac reduction and a partial impairment of miR-430 processing. Phospho-proteomic analysis revealed that Phf10/Baf45a, a chromatin remodeling factor, is less phosphorylated upon Bckdk depletion. Further, phf10 mRNA knockdown also altered ZGA, and expression of a phospho-mimetic mutant of Phf10 rescued the developmental defects observed after bckdk mRNA depletion, as well as restored H3K27ac levels. Altogether, our results demonstrate the competence of CRISPR-RfxCas13d screenings to uncover new regulators of early vertebrate development and shed light on the post-translational control of MZT mediated by protein phosphorylation. Show less

Cancer is one of the major diseases threatening human health in the world. According to the latest global cancer statistics from the International Agency for Research on Cancer (IARC), there were approximately 20 million new cancer cases and 10 million cancer deaths worldwide. Amidst this global health concern, branched chain amino acids have emerged as key players, playing an important role in the occurrence and development of cancer. In certain malignancies like colorectal cancer, the average level of BCAA in tumor tissues is twice that in normal tissues. BCAA metabolism is intricately associated with the progression of multiple tumors and is modulated by diverse enzymes, including BCAT, BCKDH, and BCKDK. The metabolism of BCAA involves multiple enzymes and biochemical processes via signaling pathways such as PI3K/AKT/mTOR and AMPK/mTOR, etc. In addition, mTOR inhibitors show potential value in cancer treatment by regulating the metabolism and signaling pathways of tumor cells, which provides a new direction for anticancer efforts. Simultaneously, BCAAs are closely associated with tumor immunity, including NK cells, CD4 Show less

Parkinson's disease (PD) is a progressive neurodegenerative disorder characterized by the selective loss of dopaminergic neurons in the substantia nigra, resulting in motor symptoms such as bradykinesia, tremor, rigidity, and postural instability, as well as a wide variety of non-motor manifestations. Branched-chain amino acids (BCAAs)-leucine, isoleucine, and valine-are essential nutrients involved in neurotransmitter synthesis, energy metabolism, and cellular signaling. Emerging evidence suggests that BCAA metabolism is intricately linked to the pathophysiology of PD. Dysregulation of BCAA levels has been associated with energy metabolism, mitochondrial dysfunction, oxidative stress, neuroinflammation, and altered neurotransmission. Furthermore, the branched-chain ketoacid dehydrogenase kinase (BCKDK), a key regulator of BCAA catabolism, has been implicated in PD through its role in modulating neuronal energetics and redox homeostasis. In this review, we synthesize current molecular, genetic, microbiome, and clinical evidence on BCAA dysregulation in PD to provide an integrative perspective on the BCAA-PD axis and highlight directions for future translational research. We explored the dualistic role of BCAAs as both potential neuroprotective agents and metabolic stressors, and critically examined the therapeutic prospects and limitations of BCAA supplementation and BCKDK targeting. Show less

Advanced renal cell carcinoma (RCC) primarily relies on targeted and immune-based therapies, yet these treatments often face limitations due to inefficacy and drug resistance. Branched-chain α-keto-acid dehydrogenase kinase (BCKDK) has been implicated in promoting RCC metastasis, but its specific substrates and the mechanisms underlying its regulation of RCC progression remain poorly understood. This study uncovers a novel mechanism whereby BCKDK-mediated AKT phosphorylation drives RCC tumorigenesis and drug resistance. Elevated BCKDK expression correlates with poor prognosis in RCC clinical samples. BCKDK deficiency inhibits RCC cell proliferation and tumorigenesis both in vitro and in vivo. Mechanistic investigations reveal that BCKDK directly binds to and regulates the phosphorylation of AKT. BCKDK-mediated phosphorylation of AKT decreases ubiquitin-mediated AKT protein degradation, and promotes tumorigenesis via activation of the AKT/mTOR signaling pathway. RNA sequencing identifies BCKDK's involvement in the drug metabolism network and apoptotic signaling pathways. The BCKDK/AKT/ABCB1 axis mediates doxorubicin resistance. Targeting BCKDK/AKT inhibits the growth of RCC patient-derived organoids (PDOs), enhances doxorubicin-induced apoptosis in RCC cells, and suppresses tumor growth in vivo. These findings identify a previously unrecognized phosphorylation substrate of BCKDK and highlight the critical role of the BCKDK/AKT signaling axis in RCC progression, offering a promising target for therapeutic intervention. Show less

Recent research has emphasized the significance of testis-specific serine proteases in regulating various aspects of sperm maturation and function. Among them, serine protease 55 (PRS55) plays an important role in the energy metabolism of sperm and is essential for male fertility in mice. A recent case study further suggests its potential importance to human fertility. However, the underlying molecular mechanism by which PRS55 influences sperm function are still not well understood. The present study aims to investigate these mechanisms further. In this study, we found impaired mitochondrial function in Prss55 Our study demonstrates that PRSS55 interacts with BCKDK and BCKDHA, and regulates BCAA metabolism and energy homeostasis, thereby facilitating sperm migration. Our study provides a biological rationale for PRSS55 as a potential therapeutic target for the treatment of male infertility in clinical. Show less

The activation of branched chain amino acid (BCAA) catabolism has garnered interest as a potential therapeutic approach to improve insulin sensitivity, enhance recovery from heart failure, and blunt tumor growth. Evidence for this interest relies in part on BT2, a small molecule that promotes BCAA oxidation and is protective in mouse models of these pathologies. BT2 and other analogs allosterically inhibit branched chain ketoacid dehydrogenase kinase (BCKDK) to promote BCAA oxidation, which is presumed to underlie the salutary effects of BT2. Potential "off-target" effects of BT2 have not been considered, however. We therefore tested for metabolic off-target effects of BT2 in Bckdk Show less

Heart failure with preserved ejection fraction (HFpEF) has become the most prevalent type of heart failure, but effective treatments are lacking. Cardiac lymphatics play a crucial role in maintaining heart health by draining fluids and immune cells. However, their involvement in HFpEF remains largely unexplored. We examined cardiac lymphatic alterations in mice with HFpEF with comorbid obesity and hypertension, and in heart tissues from patients with HFpEF. Using genetically engineered mouse models and various cellular and molecular techniques, we investigated the role of cardiac lymphatics in HFpEF and the underlying mechanisms. In mice with HFpEF, cardiac lymphatics displayed substantial structural and functional anomalies, including decreased lymphatic endothelial cell (LEC) density, vessel fragmentation, reduced branch connections, and impaired capacity to drain fluids and immune cells. LEC numbers and marker expression levels were also decreased in heart tissues from patients with HFpEF. Stimulating lymphangiogenesis with an adeno-associated virus expressing an engineered variant of vascular endothelial growth factor C (VEGFC Our study provides evidence that cardiac lymphatic disruption, driven by impaired BCAA catabolism in LECs, is a key factor contributing to HFpEF. These findings unravel the crucial role of BCAA catabolism in modulating lymphatic biology, and suggest that preserving cardiac lymphatic integrity may present a novel therapeutic strategy for HFpEF. Show less

Homologous recombination repair (HRR) is crucial for maintaining genomic stability by repairing DNA damage. Despite its importance, HRR's role in cancer progression is not fully elucidated. Here, this work shows that nuclear-localized branched-chain α-ketoacid dehydrogenase kinase (BCKDK) acts as a modulator of HRR, promoting cell resistance against DNA damage-inducing therapy in breast cancer. Mechanistically, this work demonstrates that BCKDK is localized in the nucleus and phosphorylates RNF8 at Ser157, preventing the ubiquitin-mediated degradation of RAD51, thereby facilitating HRR-mediated DNA repair under replication stress. Notably, aberrant expression of the BCKDK/p-RNF8/RAD51 axis correlates with breast cancer progression and poor patient survival. Furthermore, this work identifies a small molecule inhibitor of BCKDK, GSK180736A, that disrupts its HRR function and exhibits strong tumor suppression when combined with DNA damage-inducing drugs. Collectively, this study reveals a new role of BCKDK in regulating HRR, independent of its metabolic function, presenting it as a potential therapeutic target and predictive biomarker in breast cancer. Show less

Hepatic insulin resistance is central to type 2 diabetes (T2D) and metabolic syndrome, but defining the molecular basis of this defect in humans is challenging because of limited tissue access. Utilizing inducible pluripotent stem cells differentiated into hepatocytes from control individuals and patients with T2D and liquid chromatography with tandem mass spectrometry-based (LC-MS/MS-based) phosphoproteomics analysis, we identified a large network of cell-intrinsic alterations in signaling in T2D. Over 300 phosphosites showed impaired or reduced insulin signaling, including losses in the classical insulin-stimulated PI3K/AKT cascade and their downstream targets. In addition, we identified over 500 phosphosites of emergent, i.e., new or enhanced, signaling. These occurred on proteins involved in the Rho-GTPase pathway, RNA metabolism, vesicle trafficking, and chromatin modification. Kinome analysis indicated that the impaired phosphorylation sites represented reduced actions of AKT2/3, PKCθ, CHK2, PHKG2, and/or STK32C kinases. By contrast, the emergent phosphorylation sites were predicted to be mediated by increased action of the Rho-associated kinases 1 and 2 (ROCK1/2), mammalian STE20-like protein kinase 4 (MST4), and/or branched-chain α-ketoacid dehydrogenase kinase (BCKDK). Inhibiting ROCK1/2 activity in T2D induced pluripotent stem cell-derived hepatocytes restored some of the alterations in insulin action. Thus, insulin resistance in the liver in T2D did not simply involve a loss of canonical insulin signaling but the also appearance of new phosphorylations representing a change in the balance of multiple kinases. Together, these led to altered insulin action in the liver and identified important targets for the therapy of hepatic insulin resistance. Show less