Targeting valine catabolism to inhibit metabolic reprogramming in prostate cancer.

Metabolic reprogramming and energetic rewiring are hallmarks of cancer that fuel disease progression and facilitate therapy evasion. The remodelling of oxidative phosphorylation and enhanced lipogenesis have previously been characterised as key metabolic features of prostate cancer (PCa). Recently, succinate-dependent mitochondrial reprogramming was identified in high-grade prostate tumours, as well as upregulation of the enzymes associated with branched-chain amino acid (BCAA) catabolism. In this study, we hypothesised that the degradation of the BCAAs, particularly valine, may play a critical role in anapleurotic refuelling of the mitochondrial succinate pool, as well as the maintenance of intracellular lipid metabolism. Through the suppression of BCAA availability, we report significantly reduced lipid content, strongly indicating that BCAAs are important lipogenic fuels in PCa. This work also uncovered a novel compensatory mechanism, whereby fatty acid uptake is increased in response to extracellular valine deprivation. Inhibition of valine degradation via suppression of 3-hydroxyisobutyryl-CoA hydrolase (HIBCH) resulted in a selective reduction of malignant prostate cell proliferation, decreased intracellular succinate and impaired cellular respiration. In combination with a comprehensive multi-omic investigation that incorporates next-generation sequencing, metabolomics, and high-content quantitative single-cell imaging, our work highlights a novel therapeutic target for selective inhibition of metabolic reprogramming in PCa.

Valine aminoacyl-tRNA synthetase promotes therapy resistance in melanoma.

Transfer RNA dynamics contribute to cancer development through regulation of codon-specific messenger RNA translation. Specific aminoacyl-tRNA synthetases can either promote or suppress tumourigenesis. Here we show that valine aminoacyl-tRNA synthetase (VARS) is a key player in the codon-biased translation reprogramming induced by resistance to targeted (MAPK) therapy in melanoma. The proteome rewiring in patient-derived MAPK therapy-resistant melanoma is biased towards the usage of valine and coincides with the upregulation of valine cognate tRNAs and of VARS expression and activity. Strikingly, VARS knockdown re-sensitizes MAPK-therapy-resistant patient-derived melanoma in vitro and in vivo. Mechanistically, VARS regulates the messenger RNA translation of valine-enriched transcripts, among which hydroxyacyl-CoA dehydrogenase mRNA encodes for a key enzyme in fatty acid oxidation. Resistant melanoma cultures rely on fatty acid oxidation and hydroxyacyl-CoA dehydrogenase for their survival upon MAPK treatment. Together, our data demonstrate that VARS may represent an attractive therapeutic target for the treatment of therapy-resistant melanoma.

Structural basis of translation inhibition by a valine tRNA-derived fragment.

Translational regulation by non-coding RNAs is a mechanism commonly used by cells to fine-tune gene expression. A fragment derived from an archaeal valine tRNA (Val-tRF) has been previously identified to bind the small subunit of the ribosome and inhibit translation in Haloferax volcanii Here, we present three cryo-electron microscopy structures of Val-tRF bound to the small subunit of Sulfolobus acidocaldarius ribosomes at resolutions between 4.02 and 4.53 Å. Within these complexes, Val-tRF was observed to bind to conserved RNA-interacting sites, including the ribosomal decoding center. The binding of Val-tRF destabilizes helices h24, h44, and h45 and the anti-Shine-Dalgarno sequence of 16S rRNA. The binding position of this molecule partially overlaps with the translation initiation factor aIF1A and occludes the mRNA P-site codon. Moreover, we found that the binding of Val-tRF is associated with steric hindrance of the H69 base of 23S rRNA in the large ribosome subunit, thereby preventing 70S assembly. Our data exemplify how tRNA-derived fragments bind to ribosomes and provide new insights into the mechanisms underlying translation inhibition by Val-tRFs.

Catabolism of germinant amino acids is required to prevent premature spore germination in Bacillus subtilis.

Spores of Bacillus subtilis germinate in response to specific germinant molecules that are recognized by receptors in the spore envelope. Germinants signal to the dormant spore that the environment can support vegetative growth, so many germinants, such as alanine and valine, are also essential metabolites. As such, they are also required to build the spore. Here we show that these germinants cause premature germination if they are still present at the latter stages of spore formation and beyond, but that B. subtilis metabolism is configured to prevent this: alanine and valine are catabolized and cleared from wild-type cultures even when alternative carbon and nitrogen sources are present. Alanine and valine accumulate in the spent media of mutants that are unable to catabolize these amino acids, and premature germination is pervasive. Premature germination does not occur if the germinant receptor that responds to alanine and valine is eliminated, or if wild-type strains that are able to catabolize and clear alanine and valine are also present in coculture. Our findings demonstrate that spore-forming bacteria must fine-tune the concentration of any metabolite that can also function as a germinant to a level that is high enough to allow for spore development to proceed, but not so high as to promote premature germination. These results indicate that germinant selection and metabolism are tightly linked, and suggest that germinant receptors evolve in tandem with the catabolic priorities of the spore-forming bacterium. IMPORTANCE: Many bacterial species produce dormant cells called endospores, which are not killed by antibiotics or common disinfection practices. Endospores pose critical challenges in the food industry, where endospore contaminations cause food spoilage, and in hospitals, where infections by pathogenic endospore formers threaten the life of millions every year. Endospores lose their resistance properties and can be killed easily when they germinate and exit dormancy. We have discovered that the enzymes that break down the amino acids alanine and valine are critical for the production of stable endospores. If these enzymes are absent, endospores germinate as they are formed or shortly thereafter in response to alanine, which can initiate the germination of many different species' endospores, or to valine. By blocking the activity of alanine dehydrogenase, the enzyme that breaks down alanine and is not present in mammals, it may be possible to inactivate endospores by triggering premature and unproductive germination.

The critical role of residues Phe120 and Val161 of (2 R,3 R)­2,3­butanediol dehydrogenase from Neisseria gonorrhoeae as probed by molecular docking and site-directed mutagenesis.

NAD+-dependent (2 R,3 R)­2,3­butanediol dehydrogenase (BDH) from Neisseria gonorrhoeae (NgBDH) is a representative member of the medium-chain dehydrogenase/reductase (MDR) superfamily. To date, little information is available on the substrate binding sites and catalytic residues of BDHs from this superfamily. In this work, according to molecular docking studies, we found that conserved residues Phe120 and Val161 form strong hydrophobic interactions with both (2 R,3 R)­2,3­butanediol (RR-BD) and meso-2,3­butanediol (meso-BD) and that mutations of these residues to alanine or threonine impair substrate binding. To further evaluate the roles of these two residues, Phe120 and Val161 were mutated to alanine or threonine. Kinetic analysis revealed that, relative to those of wild type, the apparent KM values of the Phe120Ala mutant for RR-BD and meso-BD increased 36- and 369-fold, respectively; the catalytic efficiencies of this mutant with RR-BD and meso-BD decreased approximately 586- and 3528-fold, respectively; and the apparent KM values of the Val161Ala mutant for RR-BD and meso-BD increased 4- and 37-fold, respectively, the catalytic efficiencies of this mutant with RR-BD and meso-BD decreased approximately 3- and 28-fold, respectively. Additionally, the Val161Thr mutant slightly decreased catalytic efficiencies (twofold with RR-BD; 7.3-fold with meso-BD) due to an increase in KM (sixfold for RR-BD; 24-fold for meso-BD) and a slight increase (2.8-fold with RR-BD; 3.3-fold with meso-BD) in kcat. These findings validate the critical roles of Phe120 and Val161 of NgBDH in substrate binding and catalysis. Overall, the current study provides a better understanding of the substrate binding and catalysis of BDHs within the MDR superfamily.

Valsa mali PR1-like protein modulates an apple valine-glutamine protein to suppress JA signaling-mediated immunity.

Apple Valsa canker (AVC) is a devastating disease of apple (Malus × domestica), caused by Valsa mali (Vm). The Cysteine-rich secretory protein, Antigen 5, and Pathogenesis-related protein 1 (CAP) superfamily protein PATHOGENESIS-RELATED PROTEIN 1-LIKE PROTEIN c (VmPR1c) plays an important role in the pathogenicity of Vm. However, the mechanisms through which it exerts its virulence function in Vm-apple interactions remain unclear. In this study, we identified an apple valine-glutamine (VQ)-motif-containing protein, MdVQ29, as a VmPR1c target protein. MdVQ29-overexpressing transgenic apple plants showed substantially enhanced AVC resistance as compared with the wild type. MdVQ29 interacted with the transcription factor MdWRKY23, which was further shown to bind to the promoter of the jasmonic acid (JA) signaling-related gene CORONATINE INSENSITIVE 1 (MdCOI1) and activate its expression to activate the JA signaling pathway. Disease evaluation in lesion areas on infected leaves showed that MdVQ29 positively modulated apple resistance in a MdWRKY23-dependent manner. Furthermore, MdVQ29 promoted the transcriptional activity of MdWRKY23 toward MdCOI1. In addition, VmPR1c suppressed the MdVQ29-enhanced transcriptional activation activity of MdWRKY23 by promoting the degradation of MdVQ29 and inhibiting MdVQ29 expression and the MdVQ29-MdWRKY23 interaction, thereby interfering with the JA signaling pathway and facilitating Vm infection. Overall, our results demonstrate that VmPR1c targets MdVQ29 to manipulate the JA signaling pathway to regulate immunity. Thus, this study provides an important theoretical basis and guidance for mining and utilizing disease-resistance genetic resources for genetically improving apples.

The Role of Branched-chain Amino Acids and Their Metabolism in Cardiovascular Diseases.

Branched-chain amino acids (BCAAs), including leucine, isoleucine, and valine, are essential amino acids for protein synthesis. Recent studies have yielded new insights into their diverse physiological and pathological roles in health and disease. Cardiovascular diseases (CVDs) are the leading cause of morbidity and mortality globally. An increasing number of clinical studies have demonstrated that high levels of circulating BCAAs are associated with an increased risk of CVDs. Animal studies have provided preliminary evidence linking BCAA intake and metabolism with cardiovascular diseases. Despite these insights, the causal relationship between BCAA metabolism and CVD remains poorly established, and the underlying mechanisms remain incompletely understood. Here, we aim to provide an update on the current understanding of the roles of BCAAs and their metabolism in the development and progression of various CVDs. We also discuss the potential strategies targeting BCAA nutrition and metabolism for the prevention and treatment of CVDs.

Low-Molecular-Weight Fish Collagen Peptide (Valine-Glycine-Proline-Hydroxyproline-Glycine-Proline-Alanine-Glycine) Prevents Osteoarthritis Symptoms in Chondrocytes and Monoiodoacetate-Injected Rats.

The objective of this study was to investigate the effect of low-molecular-weight fish collagen (valine-glycine-proline-hydroxyproline-glycine-proline-alanine-glycine; LMWCP) on H2O2- or LPS-treated primary chondrocytes and monoiodoacetate (MIA)-induced osteoarthritis rat models. Our findings indicated that LMWCP treatment exhibited protective effects by preventing chondrocyte death and reducing matrix degradation in both H2O2-treated primary chondrocytes and cartilage tissue from MIA-induced osteoarthritis rats. This was achieved by increasing the levels of aggrecan, collagen type I, collagen type II, TIMP-1, and TIMP-3, while simultaneously decreasing catabolic factors such as phosphorylation of Smad, MMP-3, and MMP-13. Additionally, LMWCP treatment effectively suppressed the activation of inflammation and apoptosis pathways in both LPS-treated primary chondrocytes and cartilage tissue from MIA-induced osteoarthritis rats. These results suggest that LMWCP supplementation ameliorates the progression of osteoarthritis through its direct impact on inflammation and apoptosis in chondrocytes.

Analysis of the difference in metabolites and gene expressions between pre-receptive and receptive endometria / 中华医学遗传学杂志

OBJECTIVE@#To analyze the difference in the gene expression, amino acid and carnitine levels in the cervical secretions between the endometria of pre-receptive and receptive stages, with an aim to provide clues for identifying new molecular markers for endometrial receptivity.@*METHODS@#Fifty nine infertile women treated at the Department of Reproductive Medicine of Linyi People's Hospital from January 6, 2020 to January 31, 2022 were selected as as the study subjects, which were matched with 3 pairs (6 cases) of infertile women preparing for embryo transfer based on factors such as age, body mass index, and length of infertility. Endometrial tissue samples were collected for gene transcription and expression analysis. Twenty five women who had become pregnant through assisted reproductive technology were selected as the control group, and 28 non-pregnant women receiving ovulation monitoring at the Outpatient Department were enrolled as the case group. Status of endometrial receptivity was determined by ultrasonography. In the former group, endometrial tissues were sampled for sequencing, and GO and KEGG database enrichment analysis of differentially expressed genes was carried out. In the latter group, cervical secretions were collected, and amino acid and carnitine levels were measured by mass spectrometry. Statistical analysis was carried out using rank sum test, t test and chi-square test with SPSS v25.0 software.@*RESULTS@#No difference was found in the clinical data of the patients with regard to age, body mass index, infertility years, AMH, FSH, LH, E2, and type of infertility. Compared with the receptive endometrial tissues, there were 100 significantly up-regulated genes and 191 significantly down-regulated genes in the pre-receptive endometrial tissue, with the most significantly altered ones being HLA-DRB5 and MMP10. The biological processes, molecular functions and pathways enriched by more differentially expressed genes in GO and KEGG were mainly immune regulation, cell adhesion and tryptophan metabolism. Analysis of secretion metabolism also revealed a significant difference in the levels of amino acids and carnitine metabolites between the two groups (P < 0.05), in particular those of Alanine, Valine, 3-hydroxybutyrylcarnitine (C4OH) + malonylcarnitine (C3DC)/captoylcarnitine (C10).@*CONCLUSION@#A significant difference has been discovered in the levels of gene transcription and protein expression in the endometrial tissues from the pre-receptive and receptive stages. The levels of amino acids and carnitine, such as Alanine, Valine, 3-hydroxybutyryl carnitine (C4OH)+malonyl carnitine (C3DC)/caproyl carnitine (C10), may be associated with the receptive status of the endometrium, though this need to be verified with larger samples.

Enfermedad de orina a jarabe de arce / Maple syrup urine disease

Las enfermedades metabólicas pueden presentarse con síntomas, signos y laboratorios inespecíficos, que si no se consideran entre los diagnósticos diferenciales pueden retrasar el diagnóstico de estos pacientes, lo que lleva a un alto grado de secuelas neurológicas o muerte en etapas tempranas. La enfermedad de Orina a Jarabe de Arce es una enfermedad metabólica de baja incidencia caracterizada por la acumulación de niveles tóxicos de valina, isoleucina y principalmente leucina. Se presenta un paciente sin antecedentes que a los 11 días de vida comienza con mala actitud alimentaria, letargia y fontanela tensa. Descartadas las causas infectológicas se realizó un screening para enfermedades metabólicas. Se diagnosticó Leucinosis (Enfermedad de orina con olor a Jarabe de Arce) y se inició el tratamiento con restricción de leucina, valina e isoleucina en la dieta. A los pocos días del tratamiento el paciente mostró evidencias de mejoría clínica y en los parámetros de laboratorio.

Clinical signs, symptoms and lab tests of neonatal metabolic diseases may be unspecific and a high grade of suspicion is necessary to include them among the differential diagnosis avoiding a significant delay in recognizing this condition and consequent risk of neurologic handicap or early dead. Maple syrup urine disease is a congenital metabolic disorder with a low rate of prevalence and characterized by a toxic accumulation of the amino acids valine, isoleucine and mainly leucine. In this report we describe the history of a patient apparently healthy that on the 11th day after birth initiates symptoms like poor feeding, lethargy and tense fontanel. Excluded sepsis a work up for metabolic disease was performed, being diagnosed a leucinosis (Maple syrup urine disease). A dietary treatment with leucine, valine and isoleucine restriction was immediately initiated and a few days after the patient showed significant clinical and lab improvement. A short description and discussion of this disease is presented.

Enfermedad de la orina olor a jarabe de arce / Maple syrup urine disease

La enfermedad de la orina olor a jarabe de arce, es una afección metabólica producida por deficiencia en la descarboxilación oxidativa de los quetoácidos provenientes de los aminoácidos ramificados valina, isoleucina y leucina. Los pacientes parecen normales hasta los 5 a 7 días de vida, cuando muestran rechazo a la alimentación, vómitos, olor a jarabe de arce en la orina y la piel y deterioro neurológico progresivo, que lleva rápidamente al coma. Se presentan tres niños con enfermedad de la orina olor a jarabe de arce clásica, leucina >2 000 µmol/1, que fueron diagnosticados a los 10, 20 y 21 días de vida, iniciándose inmediatamente el tratamiento en base a la dieta especial. el seguimiento está basado en evaluaciones clínicas, nutricionales y bioquímicas periódicas, para adecuar los requerimientos nutricionales a la evolución de la enfermedad. La evaluación psicométrica, escala de Bayley, mostró que el coeficiente de desarrollo mental estaba entre 50 y 82, relacionándose éste con la edad de diagnóstico. Actualmente los niños tienen entre 2 y 3 años de edad, se encuentran con dieta restringida en los 3 aminoácidos ramificados. Su control debe ser frecuente para evitar desbalances metabólicos y prevenir daños neurológicos ocasionados por éstos

Comparison of 15N-labelled glycine, aspartate, valine and leucine for measurement of whole-body protein turnover

Whole-body protein turnover was measured in rats by constant infusion of 15N-labelled glycine, aspartate, valine and leucine and measuring the enrichment of hepatic and renal urea and ammonia nitrogen. The values obtained with [15N] glycine were comparable with values reported with methods based on different assumptions. [15N] Aspartate gave rise to an increased enrichment of urea and ammonia and hence to lower protein-turnover rates. [15N] Valine and [15N] leucine gave low enrichments of nitrogenous end products and hence to high protein-turnover rates. All 15N-labelled amino acids are not equally suitable for measuring whole-body protein turnover by the end-product method. The relative amounts of 15N going to the end products can be prodicted from the known individual metabolism of aspartate and the branched-chain amino acids (AU)

The catabolism of valine in the malnourished rat: studies in vivo and in vitro with different labelled forms of valine

1. The catabolism of valine was estimated in vivo by measurement of the production of labelled CO2 for 2 h after the oral administration of either [U-14C] valine. It was also estimated in vitro in homogenates of liver and muscle incubated with labelled valine. Experiments were performed in rats given diets providing either 215 g (HP) or 25 g (LP) protein per kg diet. 2. The proportion of [U-14C] valine excreted as 14 CO2 was not reduced in rats given the LP diet for 16 d but the excretion of 14 CO 2 from [1-14C] valine was reduced by 40 percent in these animals. When rats were transferred from the HP diet to the LP diet there was a reduction in the excretion of 14CO2 from [1-14C] valine; when the diet was changed from LP to HP output of 14CO2 increased to control values. 3. Homogenates of muscle and liver catabolized valine to CO2. Both liver and muscle from rats fed on the LP diet catabolized less [1-14C] valine than tissues from control animals. 4. Valine aminotransferase activity was higher in muscle than in liver, and did not change in tissues from rats fed on the LP diet. In these animals 2-ketoisovaleric acid dehydrogenase activity was reduced in both liver and muscle. 5. The production of 14CO2 was lower with [U-14C] valine as the substrate than with [1-14C]-valine and there was no difference between tissues from rats fed on the HP and LP diets. 6. The results with [1-14C] valine suggest that both liver and muscle from protein-depleted rats catabolize valine at a reduced rate. The reason for the discrepancy between these results and those with [U-14C] valine is not clear. It is concluded that the results with [U-14C] valine in vitro are affected by dilution of the label before the formation of 14CO2, but that this does not hold in vivo (AU)