Project description:Deletion of the glycerol channel aquaporin-9 (Aqp9) reduces postprandial blood glucose levels in leptin receptor deficient (db/db) obese mice on a C57BL/6×C57BLKS mixed genetic background. Furthermore, shRNA mediated reduction of Aqp9 expression reduces liver triacylglycerol (TAG) accumulation in a diet induced rat model of obesity. The aim of this study was to investigate metabolic effects of Aqp9 deletion in coisogenic db/db mice of the C57BL/6 background. Aqp9wt db/db and Aqp9-/- db/db mice did not differ in body weight and liver TAG contents. On the C57BL/6 genetic background we observed elevated plasma glucose in Aqp9-/- db/db mice (+ 1.1 mM, life-time average) while plasma insulin concentration was reduced at time of death. Glucose levels changed similarly in pentobarbital anesthetized, glucagon challenged Aqp9wt db/db and Aqp9-/- db/db mice. Liver transcriptional profiling did not detect differential gene expression between genotypes. Metabolite profiling revealed a sex independent increase in plasma glycerol (+55%), glucose (+24%) and reduction in threonate (all at q<0.1) in Aqp9-/- db/db mice compared to controls. Metabolite profiling thus confirms a role of AQP9 in glycerol metabolism of obese C57BL/6 db/db mice. In this animal model of obesity Aqp9 gene deletion elevates plasma glucose and does not alleviate hepatosteatosis.
Project description:Biallelic loss-of-function variants in the Otoferlin gene (OTOF) lead to congenital severe-to-profound sensorineural hearing loss in both humans and in mice. We developed DB-OTO, a hair cell-specific adeno-associated virus (AAV)-based dual-vector gene therapy designed to provide hearing to individuals with OTOF-related hearing loss. DB-OTO is composed of two AAV1 vectors that reconstitute a functional hOTOF gene expression cassette to form the full-length human OTOF isoform 5. A promoter based on the murine Myosin 15 (mMyo15) gene promoter was engineered to restrict the transgene expression to hair cells. The promoter construct was chosen after comparison of multiple variants using a GFP reporter in ex vivo murine explant models, followed by in vivo studies in wild-type mice and in cynomolgus monkeys. Comparison between the 1.0 kb mMyo15 and a ubiquitous promoter driving expression of hOTOFv5 transgene in mice showed that hair cell-specific expression is critical for safe expression of Otoferlin. DB-OTO induced dose-dependent establishment of auditory brainstem response and OTOF expression in inner hair cells over a 10-fold dose range sustained for at least 3 months in a mouse model of OTOF-deficiency. These data supported the initiation of a Phase 1/2 clinical trial of DB-OTO in pediatric patients with OTOF-related hearing loss.
Project description:In several models of obesity-induced diabetes, increased lipid accumulation in the liver has been associated with decreased diabetes susceptibility. For instance, deficiency in leptin receptor (db/db) leads to hyperphagia and obesity in both C57BL/6 and C57BLKS mice but, only on the C57BLKS background do the mice develop beta-cell loss leading to severe diabetes while C57BL/6 mice are relatively resistant. Liver triglyceride levels in the resistant C57BL/6 mice are 3 to 4 fold higher than in C57BLKS. To better understand the mechanisms contributing to metabolic dysfunction in obesity-induced diabetes, we used microarrays to comprehensively profile gene expression livers of F2 mice (B57BL/6 X DBA/2) deficient in leptin receptor (db/db) DBA/2J females were mated to C57BL/6 males carrying leptin receptor deficiency (db/+) and, F1 (db/+) offspring were interbred to produce F2 mice. Offspring deficient in leptin receptor (db/db) were fed on a chow diet until 5 weeks or 12 weeks of age and then euthanized for collection of liver tissue for RNA profiling along with other diabetes-related phenotypes.
Project description:We have employed whole genome microarray expression profiling as a discovery platform to identify genes differentially expressed during leptin receptor deficiency, which is partly responsible for the inhibition of T cell effector functions. Mouse CD4+CD25- T cells were purified from leptin-receptor-deficient mice and wild type mice, and stimulated with anti-CD3 and anti-CD28 for 12h. Six mice of each genotype were used. Leptin receptor deficiency-induced gene expression profiles were evaluated in mouse effector T cells from db/db mice and compared to the ones observed in their WT counterpart (db/+ mice). Two independent experiments were performed, and in each of them, 3 mice/group were pooled.
Project description:In several models of obesity-induced diabetes, increased lipid accumulation in the liver has been associated with decreased diabetes susceptibility. For instance, deficiency in leptin receptor (db/db) leads to hyperphagia and obesity in both C57BL/6 and C57BLKS mice but, only on the C57BLKS background do the mice develop beta-cell loss leading to severe diabetes while C57BL/6 mice are relatively resistant. Liver triglyceride levels in the resistant C57BL/6 mice are 3 to 4 fold higher than in C57BLKS. To better understand the mechanisms contributing to metabolic dysfunction in obesity-induced diabetes, we used microarrays to comprehensively profile gene expression livers of F2 mice (B57BL/6 X DBA/2) deficient in leptin receptor (db/db)
Project description:Asparagine endopeptidase (AEP), a cysteine proteinase found in plants and animals, plays a crucial role in regulating kidney homeostasis, immune response, and bone remodelling. It is dysregulated in cancer and neurodegenerative diseases. A study analysing protein phosphorylation in legumain knock-out mice revealed YBX1 phosphorylation on serine 102 as a key site, activating the NF-kB pathway and enhancing inflammation response in the kidney. The study also identified potential novel legumain substrates, providing insights into its role in cellular processes.
Project description:Gene expression of liver tissue from db/db untreated (6x replicates) and db/db treated with 5mg/kg of 3c7.v44 mAb (6x replicates). Anti-GCGR antibody treatment in db/db mice: fig 2b in Solloway et al.
Project description:The aim of this project was to profile the proteome of mouse-derived serum in order to identify those that showed significant quantitative different proteins among leptin-deficient (db/db) mouse, the genetic non-alcoholic fatty liver disease (NAFLD) mouse model and their lean bks mouse group.
Project description:The aim of this project was to profile the proteome of mouse-derived liver in order to identify those that showed significant quantitative different proteins among leptin-deficient (db/db) mouse, the genetic non-alcoholic fatty liver disease (NAFLD) mouse model and their lean BKS mouse group.
Project description:To identify putative lncRNA changes in the livers of db/db mice and C57 mice, we isolated the liver tissues and carried out a microarray analysis. Here, we found significant changes of lncRNAs in the livers of db/db mice. Among them, abnormal expression of ultraconserved elements was noticed.