Project description:Mitochondrial dysfunction has been reported in obesity and insulin resistance, but primary genetic mitochondrial dysfunction is generally not associated with these, arguing against a straightforward causal relationship. A rare exception, recently identified in humans, is a syndrome of lower body adipose loss, leptin-deficient severe upper body adipose overgrowth, and insulin resistance caused by the p.Arg707Trp mutation in MFN2, encoding mitofusin-2. How this selective perturbation of mitochondrial function leads to tissue- and adipose depot-specific growth abnormalities and systemic biochemical perturbation is unknown. To address this, Mfn2R707W/R707W knock-in mice were generated and phenotyped on chow and high fat diets. Electron microscopy revealed adipose-specific mitochondrial morphological abnormalities. Oxidative phosphorylation by isolated mitochondria was unperturbed, but the cellular integrated stress response was activated in adipose tissue. Fat mass and distribution, body weight, and systemic glucose and lipid metabolism were unchanged, however serum leptin and adiponectin concentrations, and their secretion from adipose explants were reduced. Pharmacological induction of the integrated stress response in wild-type adipocytes also reduced secretion of leptin and adiponectin, suggesting an explanation for the in vivo findings. These data suggest that the p.Arg707Trp MFN2 mutation perturbs mitochondrial morphology and activates the integrated stress response selectively in adipose tissue. In mice, this does not disrupt most adipocyte functions or systemic metabolism, whereas in humans it is associated with pathological adipose remodelling and metabolic disease. In both species, disproportionate effects on leptin secretion may relate to cell autonomous induction of the integrated stress response.
Project description:The Mfn2 gene was conditionally knock-out from male mice germ cells using Stra8-Cre mice. The spermatocytes were collected from PD 24 and PD 52 male mice, and were further isolated as pachytene cells (P) and leptotene/zygotene cells (L/Z). The transcriptome between MFN2 WT and MFN2 cKO spermatocytes were analyzed via RNA-seq in P and L/Z populations at different ages, PD 24 amd PD 52, respectively.
Project description:We injected LLC1 cells into the tibia of DMP1-Cre Mfn2-/- mice, DMP1-Cre Rhot1-/- mice, and wild-type mice to study the changes in the cellular composition of the cancer microenvironment after knockout of Mfn2 or Rhot1 in osteocytes.
Project description:RNAseq of enterocytes of the jejunum and Ileum from transgene C57BL/6 mice to assess the effects of a CKIα knock-out in combination with expression of a p53 mutant protein (R172H ) compared to a double knock-out of CKIα and p53. In addition, a group of mice exhibiting a CKIα knock-out and mutant p53 (R172H) was treated with gallic acid and compared to untreated mice (Jejunum only).
Project description:We have generated CRISPR edited versions of hESC line MShef11 to produce MFN2 R94Q/+ and MFN2 R94Q/R94Q lines as a model for Charcot Marie Tooth Disease (CMT) 2A. This were differentiated to limb innervating motor neurons, the predominantly affected cell time in CMT2A and RNA was examined to investigate differences in cell lines.
Project description:Mitofusin-2 (MFN2) is an outer mitochondrial membrane protein essential for mitochondrial networking in most cells. Autosomal dominant mutations in the MFN2 gene cause Charcot-Marie-Tooth type 2A disease (CMT2A), a severe and disabling sensory-motor neuropathy with impact on the entire nervous system. To date, no curative treatment is available. In the paper we propose a novel therapeutic strategy tailored to correct the root genetic defect of CMT2A. In our approach, while mutant and wild-type MFN2 mRNA are inhibited by RNA interference (RNAi), the wild-type protein is restored by overexpressing a cDNA encoding a functional MFN2, modified to be resistant to RNAi. This strategy allows proper MFN2 molecular correction in vivo in the MitoCharc1 CMT2A transgenic mouse model after cerebrospinal fluid (CSF) delivery of the constructs via adenoassociated virus 9 (AAV9) in newborn mice. To identify the therapeutic molecular mechanisms and the pathway that are modulated, we have compared the bulk RNA expression profile of spinal cord from one month old wild type (WT) mice and MitoCharc1 transgenic mice (B6;D2-Tg(Eno2-MFN2*R94Q)L51Ugfm/J) which encode the mutant human MFN2*R94Q under the neuron specific rat enolase (Eno2) promoter, as potential mouse model to test the therapeutic approach. We performed gene expression profiling analysis using data (RNA-seq) obtained from 4 wild type mice and 8 MitoCharch1 transgenic mice at one time point.
Project description:The majority of diabetics are susceptible to cardiac dysfunction and heart failure, while conventional drug therapy cannot correct diabetic cardiomyopathy (DCM) progression. Herein, we assessed the potential role and therapeutic value of ubiquitin-specific protease 28 (USP28) on the metabolic vulnerability of DCM. PPARα-/- in the db/db background mice were constructed to check the mechanism of USP28 in vivo. Inducible cardiac-specific deletion of Mfn2 in the db/db background mice was utilized to evaluate USP28-mediated cardioprotection. chromatin immunoprecipitation (ChIP) assays revealed that PPARα promote mitofusin 2 (Mfn2) transcription, thereby impeding mitochondrial morphofunctional defects.