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:Cobalamin C deficiency (cblC), the most common inborn error of intracellular cobalamin metabolism, is caused by mutations in MMACHC, a gene responsible for the processing and intracellular trafficking of vitamin B12. This recessive disorder is characterized by a failure to metabolize cobalamin into adenosyl- and methylcobalamin, which results in the biochemical perturbations of methylmalonic acidemia, hyperhomocysteinemia, and hypomethioninemia caused by impaired activity of the downstream enzymes, methylmalonyl-CoA mutase and methionine synthase. Cobalamin C deficiency can be accompanied by a wide spectrum of clinical manifestations, including progressive blindness, and in mice, manifests with very early embryonic lethality. Because zebrafish harbor a full complement of cobalamin metabolic enzymes, we used genome editing to study loss of mmachc function. mmachc homozygotes survived the embryonic period but perished in early juvenile life. The mutants displayed metabolic and clinical features of cblC deficiency including methylmalonic acidemia, severe growth retardation, and lethality. Clinical and metabolic parameters improved when the mutants were raised in water supplemented with small molecules used to treat patients, including hydroxocobalamin, methylcobalamin, methionine, and betaine. Furthermore, mmachc mutants, some bred to express rod and or cone fluorescent reporters, manifested a retinopathy and thin optic nerves. Expression analysis using whole eye mRNA revealed dysregulation of genes involved in phototransduction and cholesterol metabolism. Zebrafish with mmachc deficiency recapitulate the phenotypic and biochemical features of the human disorder, including ocular pathology, and a show a response to established treatments
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:Primary graft dysfunction (PGD) continues to be a major cause of early death after lung transplantation. Moreover, there remains a lack of accurate pre-transplant molecular markers for predicting PGD. To identify distinctive gene expression signatures associated with PGD, we profiled human donor lungs using microarray technology prior to the graft implantation. The genomic profiles of 10 donor lung samples from patients who subsequently developed clinically defined severe PGD were compared with 16 case-matched donor lung samples from those who had a favorable outcome without PGD. Matched factors used were: recipient age (± 10 years), recipient gender, recipient lung disease, and type of transplantation (single or bilateral). Keywords: Observational case-control study Matched case-control observational study: 10 primary graft dysfunction cases vs 16 Good outcome cases. One replicate per array.