Project description:Mitochondria have an independent genome (mtDNA) and protein synthesis machinery that coordinately activate for mitochondrial generation. Here, we report that Krebs cycle intermediate, fumarate, connects metabolism to mitobiogenesis through binding to malic enzyme 2 (ME2). Proteomic profiling of ME2-interacting protein reveals that ME2 binds to mitoribosome proteins to regulate mitoribosome assembly and mtDNA-encoded protein production. ME2 also interacts with and modulates deoxyuridine 5-triphosphate nucleotidohydrolase activity to regulate thymidine generation and mtDNA abundance
Project description:Diet may be modified seasonally or by biogeographic, demographic or cultural shifts. It can differentially influence mitochondrial bioenergetics, retrograde signalling to the nuclear genome, and anterograde signalling to mitochondria. All these interactions have the potential to influence the frequencies of mtDNA types in nature and human health. In a model laboratory system, we fed four diets varying in Protein: Carbohydrate (P:C) ratio (1:2, 1:4, 1:8 and 1:16 P:C) to four Drosophila mitotypes and assayed their frequency in population cages. The nuclear genome was standardised. When fed a high protein 1:2 P:C diet, the frequency of flies harbouring Alstonville mtDNA increased. In contrast, when fed the high carbohydrate 1:16 P:C food the incidence of flies harbouring Dahomey mtDNA increased. This result was repeated when the laboratory diet was replaced by natural fruits having high and low P:C ratios and when the nuclear genome was permuted. Quaternary structural modelling, in vitro assays of electron transport chain protein complexes, and protein gels suggested a V161L mutation in the ND4 subunit of Complex I of Dahomey mtDNA was functionally deleterious and resulted in an increase in larval development time on the 1:2 P:C diet. Conversely, the 1:16 P:C diet resulted in an elegant remodelling of energy metabolism and relative reduction in development time of larvae harbouring Dahomey mtDNA. These data question the use of mtDNA as an assumed neutral maker. We posit that humans with specific mtDNA variations may differentially metabolise carbohydrates, which has implications for a variety of first-world diseases including cardiovascular disease, diabetes, obesity and perhaps Parkinson’s Disease.
Project description:Type 2 diabetes (T2D), one of the most common metabolic diseases, is the result of insulin resistance or impaired insulin secretion by mitochondrial dysfunctions. Mitochondrial DNA (mtDNA) polymorphisms play an important role in physiological and pathological characteristics of T2D, however, their mechanism is poorly understood. To directly identify candidate mtDNA variants associated with T2D at the genome-wide level, we constructed forty libraries from ten patients with T2D and thirty control individuals for deep sequencing. We characterized their mtDNA atlas, and analyzed their single nucleotide polymorphisms (MtSNPs), insertions and deletions (InDels), and screened potential mtDNA mutation sites associated with T2D. We found ten mtDNA polymorphisms at nucleotides 489T > C, 3105AC > A, 3107N > C, 8701A > G, 9540T > C, 10398A > G, 10400C > T, 10873T > C, 12705C > T and 14783T > C that showed a significant difference between patients and control subjects. Therefore, our results characterize mtDNA atlas of patients with T2D, and further demonstrate that mtDNA variants are participated in the pathophysiology of T2D and other diseases. In addition, mtDNA variants may be candidate molecular biomarkers of T2D, and they may be valuable for early diagnosis of T2D in the future.
Project description:Primary objectives: The primary objective is to investigate circulating tumor DNA (ctDNA) via deep sequencing for mutation detection and by whole genome sequencing for copy number analyses before start (baseline) with regorafenib and at defined time points during administration of regorafenib for treatment efficacy in colorectal cancer patients in terms of overall survival (OS).
Primary endpoints: circulating tumor DNA (ctDNA) via deep sequencing for mutation detection and by whole genome sequencing for copy number analyses before start (baseline) with regorafenib and at defined time points during administration of regorafenib for treatment efficacy in colorectal cancer patients in terms of overall survival (OS).