Project description:Methylmalonic acidemia (MMA), an organic acidemia characterized by metabolic instability and multiorgan complications, is most frequently caused by mutations in methylmalonyl-CoA mutase (MUT). To define the metabolic adaptations in MMA, in the chronic and acute settings, we studied a mouse model generated by transgenic expression of Mut in the muscle. Mut-/-;TgINS-MCK-Mut mice accurately replicate the hepato-renal mitochondriopathy and growth failure seen in severely affected patients, and were used to characterize the response to fasting. The hepatic transcriptome in MMA mice was characterized by the chronic activation of stress-related pathways and responded abberrantly to fasting when compared to controls.
Project description:Methylmalonic acidemia (MMA) is a rare inborn error of propionate metabolism caused by deficiency of the mitochondrial methylmalonyl-CoA mutase (MUT) enzyme. As matter of fact, MMA patients manifest impairment of the primary metabolic network with profound damages that involve several cell components, many of which have not been discovered yet. We employed cellular models and patients-derived fibroblasts to refine and uncover new pathologic mechanisms connected with MUT deficiency through the combination of multi-proteomics and bioinformatics approaches.
Project description:Isolated methylmalonic acidemia (MMA) is a pleiotropic enzymatic defect of branched-chain amino acid oxidation most commonly caused by deficiency of methylmalonyl-CoA mutase (MUT). End stage renal disease (ESRD) is emerging as an inevitable disease-related complication, recalcitrant to conventional therapies and liver transplantation. To establish a viable model of MMA-associated renal disease, methylmalonyl-CoA mutase (Mut) was expressed in the liver of Mut -/- mice as a stable transgene under the control of an albumin (INS-Alb-Mut) promoter. Mut -/- ;TgINS-Alb-Mut mice were rescued from the neonatal lethality displayed by Mut -/- mice and manifested a decreased glomerular filtration rate (GFR), chronic tubulointerstital nephritis (CTIN) and prominent ultrastructural changes in the proximal tubular mitochondria, replicating precisely the renal manifestations seen in a large MMA patient cohort.
Project description:Isolated methylmalonic acidemia (MMA) is a pleiotropic enzymatic defect of branched-chain amino acid oxidation most commonly caused by deficiency of methylmalonyl-CoA mutase (MUT). End stage renal disease (ESRD) is emerging as an inevitable disease-related complication, recalcitrant to conventional therapies and liver transplantation. To establish a viable model of MMA-associated renal disease, methylmalonyl-CoA mutase (Mut) was expressed in the liver of Mut -/- mice as a stable transgene under the control of an albumin (INS-Alb-Mut) promoter. Mut -/- ;TgINS-Alb-Mut mice were rescued from the neonatal lethality displayed by Mut -/- mice and manifested a decreased glomerular filtration rate (GFR), chronic tubulointerstital nephritis (CTIN) and prominent ultrastructural changes in the proximal tubular mitochondria, replicating precisely the renal manifestations seen in a large MMA patient cohort. To explore the pathophysiological changes that underlie the renal disease of MMA, we compared gene expression profiles of whole kidney mRNA samples between 4 female Mut +/+, Mut +/- and Mut -/- ;TgINS-Alb-Mut mice after they ingested a HP diet for 2 months. Females were used because more survived the dietary challenge, whereas the histology, ultrastructure and GFR effects were identical between sexes
Project description:Methylmalonic academia (MMA) is a rare inborn error of the metabolism due to defects of the methylmalonyl-CoA mutase (MUT) enzyme that result in methylmalonic acid accumulation in the blood and increased excretion in urine. Affected patients can manifest vomiting, dehydration, hypotonia, developmental delay and failure to thrive. The emergency treatment of the newborns with MMA mainly comprises rehydration and promotion of anabolism, followed by long-term dietary management that mostly includes restriction of propiogenic amino acids by a low protein diet and carnitine and vitamin B12 supplementation. The effects of MUT deficiency on the cellular damage in patients is still unknown. Fibroblasts obtained from two distinct MMA patients were analyzed by shotgun label-free quantitative (LFQ) proteomics.
Project description:Systemic levels of methylmalonic acid (MMA), a byproduct of propionate metabolism, increase with age and MMA promotes tumor progression via its direct effects in tumor cells. However, the role of MMA in modulating the tumor ecosystem remains to be investigated. The proliferation and function of CD8+ T cells, key anti-tumor immune cells, declines with age and in conditions of vitamin B12 deficiency, which are the two most well-established conditions that lead to increased systemic levels of MMA. Thus, we hypothesized that increased circulatory levels of MMA would lead to a suppression of CD8+ T cell immunity. Treatment of primary CD8+ T cells with MMA induced a dysfunctional phenotype characterized by robust immunosuppressive transcriptional reprogramming and marked increases in the expression of the exhaustion regulator, TOX. Accordingly, MMA treatment upregulated exhaustion markers in CD8+ T cells and decreased their effector functions, which drove the suppression of anti-tumor immunity in vitro and in vivo. Mechanistically, MMA-induced CD8+ T cell exhaustion was associated with a suppression of NADH-regenerating reactions in the TCA cycle and concomitant defects in mitochondrial function. Thus, MMA has immunomodulatory roles, thereby highlighting MMA as an important link between aging, immune dysfunction, and cancer.
Project description:Methylmalonic acidemia (MMA) is one of the most common inherited metabolic disorders, due to deficiency of the mitochondrial methylmalonyl ̶ coenzyme A mutase (MUT). How MUT deficiency triggers mitochondrial alterations and cell damage remains unknown, preventing the development of disease-modifying therapies. To assess the effect of MUT deficiency on gene expression we investigated the transcriptome of in kidney cells derived from healthy controls or patients with MMA who harbor inactivating mutations in MUT. Microarray data indicate that MUT deficiency induces a profound and global change in gene expression that may be in part responsible of cellular alterations observed in patient cells.
Project description:From age 65 onwards, the risk of cancer incidence and associated mortality is substantially higher. Nonetheless, our understanding of the complex relationship between age and cancer is still in its infancy. For decades, the link has largely been attributed to increased exposure time to mutagens in older individuals. However, this view does not account for the well-established role of diet, exercise and small molecules that target the pace of metabolic aging. Here, we show that metabolic alterations that occur with age can render a systemic environment favorable to progression and aggressiveness of tumors. Specifically, we show that methylmalonic acid (MMA), a by-product of propionate metabolism, is significantly up-regulated in the serum of older people, and functions as a mediator of tumor progression. We traced this to the induction of SOX4 and a consequent transcriptional reprogramming that can endow cancer cells with aggressive properties. Thus, accumulation of MMA represents a novel link between aging and cancer progression, implicating MMA as a novel therapeutic target for advanced carcinomas.
Project description:The systemic metabolic shifts that occur during aging and the local metabolic alterations of a tumor, its stroma and their communication cooperate to establish a unique tumor microenvironment (TME) that fosters cancer progression. Here, we show that methylmalonic acid (MMA), an aging-increased oncometabolite that is also produced by aggressive cancer cells, activates fibroblasts in the TME and stimulates the release of extracellular vesicles (EVs) that drive cancer progression, drug resistance and metastasis. The cancer-associated fibroblast (CAF)-released EV cargo is modified as a result of reactive oxygen species (ROS) generation and activation of the canonical and noncanonical TGFβ signaling pathways in CAFs. EV-associated IL-6 functions as a stroma-tumor messenger that activates the JAK/STAT3 and TGFβ signaling pathways in tumor cells and promote an epithelial-to-mesenchymal transition (EMT) and drug resistance in vitro, and metastatic progression in vivo. Our findings reveal the role of MMA in the activation of CAFs to drive metastatic reprogramming, unveiling multiple potential therapeutic avenues to target MMA at the nexus of aging, the tumor microenvironment and metastasis.
2022-10-04 | GSE190929 | GEO
Project description:combined methylmalonic acidemia and homocysteinemia