Project description:We characterized the metabolic and cardiac mitochondrial function in a mouse model of non-ischemic HF. Inhibition of nitric oxide synthesis and hypertension, which often present together, are two important risk factors in human non-ischemic HF. Compared with L-NAME L-NG-Nitroarginine methyl ester (L-NAME), an inhibitor of nitric oxide synthesis or Angiotensin II (AngII), a hypertensive agent treatment alone, L-NAME+AngII induced the most severe HF phenotype characterized by edema, hypertrophy, fibrosis, increased blood pressure and reduced ejection fractions. L-NAME+AngII treated mice had robust deterioration of cardiac mitochondrial function we observed. Microarray analyses revealed majority of the gene changes attributed to the combination of L-NAME+AngII. Pathway analyses indicated significant changes in metabolic pathways such as mitochondrial oxidative phosphorylation, fatty acid metabolism and tricarboxylic acid pathways etc.in L-NAME+AngII hearts. We conclude that combination of L-NAME+AngII exacerbates cardiac contractile and mitochondrial functional de-regulation compared with L-NAME and AngII alone, resulting in non-ischemic HF. This model of heart failure may be highly valuable in studying mechanisms and treatments for non-ischemic heart failure.
Project description:Reconstructing lineage relationships in complex tissues can reveal mechanisms underlying development and disease. Recent methods combine single-cell transcriptomics with mitochondrial DNA variant detection to establish lineage relationships in primary human cells, but are not scalable to interrogate complex tissues. To overcome this limitation, here we develop a technology for high-confidence detection of mitochondrial mutations from high-throughput single-cell RNA-sequencing. We use the new method to identify skewed immune cell expansions in primary human clonal hematopoiesis.
Project description:We characterized the metabolic and cardiac mitochondrial function in a mouse model of non-ischemic HF. Inhibition of nitric oxide synthesis and hypertension, which often present together, are two important risk factors in human non-ischemic HF. Compared with L-NAME L-NG-Nitroarginine methyl ester (L-NAME), an inhibitor of nitric oxide synthesis or Angiotensin II (AngII), a hypertensive agent treatment alone, L-NAME+AngII induced the most severe HF phenotype characterized by edema, hypertrophy, fibrosis, increased blood pressure and reduced ejection fractions. L-NAME+AngII treated mice had robust deterioration of cardiac mitochondrial function we observed. Microarray analyses revealed majority of the gene changes attributed to the combination of L-NAME+AngII. Pathway analyses indicated significant changes in metabolic pathways such as mitochondrial oxidative phosphorylation, fatty acid metabolism and tricarboxylic acid pathways etc.in L-NAME+AngII hearts. We conclude that combination of L-NAME+AngII exacerbates cardiac contractile and mitochondrial functional de-regulation compared with L-NAME and AngII alone, resulting in non-ischemic HF. This model of heart failure may be highly valuable in studying mechanisms and treatments for non-ischemic heart failure. Twelve week-old C57BL6 male mice were randomly assigned to 4 groups: 1. Control, 2. L-NAME treatment, 3. AngII treatment, 4. L-NAME+AngII treatment.L-NAME (0.3 mg/ml with 1% NaCl) was administered in drinking water. AngII (0.7 mg/kg/day) was administered via subcutaneous micro-osmotic pumps. L-NAME and AngII were administered to mice for 5 weeks and 4 weeks in combination to induce HF or alone to study the effects of the individual agents.
Project description:Muscle tissue was longitudinally characterized histologically for electron transport function by staining 1mm of quadriceps muscle at 70 micron intervals for the activities of two complexes in the mitochondrial electron transport chain, Cytochrome C Oxidase and Succinate Dehydrogenase. Unstained serial cryosections were prepared for Laser Capture Microdissection. Target cells from the serial sections were isolated and pooled for RNA extraction, amplification and hybridization on Affymetrix microarrays. We selected homogeneous populations of muscle fibers for expression profiling based upon the presence/absence of electron transport dysfunction caused by the somatic accumulation of mitochondrial DNA deletion mutations. The design of this experiment is limited by the source tissue which is individually identified cells harboring intracellular clonal expansions of mitochondrial DNA deletion mutations. These unique and rare cells were identified in rat Vastus lateralis tissue in an aged 36-month old F344xBN F1 hybrid rat by exhaustive serial sectioning and subsequent histological characterization. Unstained serial sections where isolated by LCM and the purified RNA was amplified by 2 rounds of RNA based transcription prior to fragmentation and hybridization on rat genome affymetrix chips. Two populations of cells were analyzed, Electron transport deficient and normal control cells from the same animal.
Project description:Abstract:The pRb tumor suppressor protein associates with chromatin and regulates gene expression. Numerous studies have identified Rb-dependent RNA signatures, but the proteomic effects of Rb-loss are largely unexplored. We have acutely ablated Rb in adult mice and conducted quantitative analysis of RNA and proteomic changes in colon and lung, where Rb-loss was sufficient or insufficient to induce ectopic proliferation respectively. As expected, RbKO caused similar increases in classic pRb/E2F-regulated transcripts in both tissues, but unexpectedly their protein products increased only in the colon, consistent with its increased proliferative index. Thus, these protein changes induced by Rb-loss are coupled with proliferation, but uncoupled from transcription. The proteomic changes in common between RbKO tissues showed a striking decrease in proteins with mitochondrial functions. Accordingly, RB1 inactivation in human cells decreased both mitochondrial mass and OXPHOS function. RBKO cells showed decreased mitochondrial respiratory capacity and the accumulation of hypopolarized mitochondria. Additionally, RB/Rb-loss altered mitochondrial pyruvate oxidation from 13C-Glucose through the TCA cycle in both cells and mouse tissues. Consequently, RBKO cells have an enhanced sensitivity to mitochondrial stress conditions. In summary, proteomic analyses provide a new perspective on Rb/RB1 mutation, highlighting the importance of pRb for mitochondrial function and suggesting vulnerabilities for treatment.