Project description:Protein homeostasis, or proteostasis is critical for organelle function, including mitochondria, but its role in cancer is controversial. Here, we show that transgenic mice expressing the mitochondrial chaperone, TRAP1 in the prostate develop prostatic hyperplasia and cellular atypia. When examined on a Pten+/- background, a common alteration in prostate cancer patients, TRAP1 transgenic mice showed accelerated incidence of invasive prostatic adenocarcinoma, characterized by increased cell proliferation and reduced apoptosis, in situ. Conversely, homozygous deletion of TRAP1 delays prostatic tumorigenesis in Pten+/- mice, without affecting hyperplasia or prostatic intraepithelial neoplasia (PIN). Global RNA sequencing and reverse phase protein array profiling of Pten+/--TRAP1 transgenic tumors reveals modulation of oncogenic networks of cell proliferation, apoptosis, cell motility, DNA damage and metabolism. Mechanistically, reconstitution of Pten+/- prostatic epithelial cells with TRAP1 results in increased cell proliferation, reduced apoptosis, heightened cell invasion, and no changes in mitochondrial bioenergetics. Therefore, TRAP1 promotes invasive prostate cancer, and provides an “actionable” therapeutic target in patients with advanced disease.
Project description:Here we show that TRAP1 directly binds translation elongation factors, both inside and outside mitochondria, and slows down translation. TRAP1 overexpression or silencing affects the synthesis of respiratory complex components. Inside mitochondria, TRAP1 binds the Complex III core component UQCRC2 and regulates Complex III activity. This decreases respiration rate upon basal condition but allows sustained oxidative phosphorylation when glucose is limiting, a condition in which TRAP1-UQCRC2 binding is lost. In humans, TRAP1 is co-expressed with the mitochondrial translational machinery, which synthesize respiratory complex proteins. Altogether, our results show an unprecedented level of complexity in the regulation of cancer cell metabolism, in which mitochondrial and cytosolic protein synthesis are co-regulated with energetic metabolism through the contribution of a common molecular chaperone
Project description:TRAP1 is a HSP90 molecular chaperone involved in cancer cell adaptation to unfavorable environments and metabolic reprogramming. The role of TRAP1 in the adaptive response to hypoxia was investigated in human colorectal cancer.
Project description:The molecular chaperone TRAP1, the mitochondrial isoform of cytosolic HSP90, remains poorly understood with respect to its pivotal role in the regulation of mitochondrial metabolism. Most studies have found it to be an inhibitor of mitochondrial oxidative phosphorylation (OXPHOS) and an inducer of the Warburg phenotype of cancer cells. However, others have reported the opposite and there is no consensus on the relevant TRAP1 interactors. This calls for a more comprehensive analysis of the TRAP1 interactome and of how TRAP1 and mitochondrial metabolism mutually affect each other.
Project description:The molecular chaperone TRAP1, the mitochondrial isoform of cytosolic HSP90, remains poorly understood with respect to its pivotal role in the regulation of mitochondrial metabolism. Most studies have found it to be an inhibitor of mitochondrial oxidative phosphorylation (OXPHOS) and an inducer of the Warburg phenotype of cancer cells. However, others have reported the opposite and there is no consensus on the relevant TRAP1 interactors. This calls for a more comprehensive analysis of the TRAP1 interactome and of how TRAP1 and mitochondrial metabolism mutually affect each other. We show that the disruption of the gene for TRAP1 in a panel of cell lines dysregulates OXPHOS by a metabolic rewiring that induces the anaplerotic utilization of glutamine metabolism to replenish TCA cycle intermediates. Restoration of wild-type levels of OXPHOS requires full-length TRAP1. Whereas the TRAP1 ATPase activity is dispensable for this function, it modulates the interactions of TRAP1 with various mitochondrial proteins. Quantitatively by far the major interactors of TRAP1 are the mitochondrial chaperones mtHSP70 and HSP60. However, we find that the most stable stoichiometric TRAP1 complex is a TRAP1 tetramer, whose levels change in response to both a decline or an increase in OXPHOS. Our work provides a roadmap for further investigations of how TRAP1 and its interactors such as the ATP synthase regulate cellular energy metabolism. Our results highlight that TRAP1 function in metabolism and cancer cannot be understood without a focus on TRAP1 tetramers as potentially the most relevant functional entity.
Project description:The tendency of mitochondria to undergo or resist BCL2-controlled apoptosis (so-called mitochondrial priming) is a powerful predictor of response to cytotoxic chemotherapy. To fully exploit this finding, it will be important to understand the molecular genetic contexts responsible for the relative mitochondrial priming of chemotherapy-sensitive versus resistant cell populations. Here, we report that mitochondrial apoptosis resistance in T-cell acute lymphoblastic leukemia (T-ALL) is mediated by inactivation of polycomb repressive complex 2 (PRC2). In T-ALL clinical samples from children with T-ALL treated on recent Dana-Farber Cancer Institute or Children’s Oncology Group clinical trials, we found that loss-of-function mutations in any of three core components of PRC2 (EZH2, EED or SUZ12) were associated with resistance to mitochondrial apoptosis. In human T-ALL cells, PRC2 depletion induced resistance to apoptosis induction by multiple chemotherapeutics with distinct mechanisms of action, including dexamethasone, doxorubicin and vincristine. PRC2 loss induced apoptosis resistance via transcriptional upregulation of the LIM domain transcription factor CRIP2, and subsequent downstream upregulation of the mitochondrial chaperone TRAP1. Importantly, TRAP1 overexpression was necessary to induce resistance to chemotherapy-induced apoptosis downstream of PRC2 inactivation, and pharmacologic inhibition of TRAP1 synergized with dexamethasone and doxorubicin. These findings demonstrate the importance of relative mitochondrial apoptotic priming as a prognostic factor in T-ALL, and implicate mitochondrial chaperone function as a molecular determinant of response to cancer chemotherapy, suggesting a rationale for targeted therapeutic intervention.
Project description:There is growing evidence of mitochondrial disturbance in autism spectrum disorders (ASD) but causative relations remain to be established. We identified postzygotic mozaicp.Q639* mutation in the TRAP1 gene encoding mitochondrial chaperone of the HSP90 family in ASD patient whose monozygotic twin brother was healthy. An additional survey of 176 unrelated ASD probands showed identical TRAP1 variant in a single male patient. We generated a knock-in Trap1 p.Q641*mouse which displayed behavioral abnormalities relevant for ASD, that were more pronounced in males. This effect was corroborated by gender-specific differences in synaptic plasticity and the density of synaptic mitochondria. Next we performed transcriptome profiling by sequencing of RNA isolated from hippocampi of WT, HET and MUT male and female mice
Project description:Introgressed variants from other species can be an important source of genetic variation because they may arise rapidly, can include multiple mutations on a single haplotype, and have often been pretested by selection in the species of origin. Although introgressed alleles are generally deleterious, several studies have reported introgression as the source of adaptive alleles-including the rodenticide-resistant variant of Vkorc1 that introgressed from Mus spretus into European populations of Mus musculus domesticus. Here, we conducted bidirectional genome scans to characterize introgressed regions into one wild population of M. spretus from Spain and three wild populations of M. m. domesticus from France, Germany, and Iran. Despite the fact that these species show considerable intrinsic postzygotic reproductive isolation, introgression was observed in all individuals, including in the M. musculus reference genome (GRCm38). Mus spretus individuals had a greater proportion of introgression compared with M. m. domesticus, and within M. m. domesticus, the proportion of introgression decreased with geographic distance from the area of sympatry. Introgression was observed on all autosomes for both species, but not on the X-chromosome in M. m. domesticus, consistent with known X-linked hybrid sterility and inviability genes that have been mapped to the M. spretus X-chromosome. Tract lengths were generally short with a few outliers of up to 2.7 Mb. Interestingly, the longest introgressed tracts were in olfactory receptor regions, and introgressed tracts were significantly enriched for olfactory receptor genes in both species, suggesting that introgression may be a source of functional novelty even between species with high barriers to gene flow.
Project description:Translational research is commonly performed in the C57B6/J mouse strain, chosen for its genetic homogeneity and phenotypic uniformity. Here, we evaluate the suitability of the white-footed deer mouse (Peromyscus leucopus) as a model organism for aging research, offering a comparative analysis against C57B6/J and diversity outbred (DO) Mus musculus strains. Our study includes comparisons of body composition, skeletal muscle function, and cardiovascular parameters, shedding light on potential applications and limitations of P. leucopus in aging studies. Notably, P. leucopus exhibits distinct body composition characteristics, emphasizing reduced muscle force exertion and a unique metabolism, particularly in fat mass. Cardiovascular assessments showed changes in arterial stiffness, challenging conventional assumptions and highlighting the need for a nuanced interpretation of aging-related phenotypes. Our study also highlights inherent challenges associated with maintaining and phenotyping P. leucopus cohorts. Behavioral considerations, including anxiety-induced responses during handling and phenotyping assessment, pose obstacles in acquiring meaningful data. Moreover, the unique anatomy of P. leucopus necessitates careful adaptation of protocols designed for Mus musculus. While showcasing potential benefits, further extensive analyses across broader age ranges and larger cohorts are necessary to establish the reliability of P. leucopus as a robust and translatable model for aging studies.