Project description:In type 1 diabetes (T1D), the innate and adaptive immune systems attack and eventually destroy the insulin-secreting islet β cells. During this process, β cells activate inflammatory signaling pathways that augment the dysfunction and destruction imposed by cellular autoimmunity. The 12-lipoxygenase (12-LOX) pathway produces the pro-inflammatory eicosanoid 12-HETE, which induces oxidative and endoplasmic reticulum stress and results in diminished insulin secretion and apoptosis. The G protein-coupled receptor 31 (GPR31) has been identified as a putative receptor for 12-HETE. In this study, we generated conventional GPR31 knockout mice. To interrogate the role of GPR31 in β cells, we treated islets from wildtype and Gpr31b-/- mice with proinflammatory cytokines and subjected the islets to RNA sequencing. Differentially expressed genes in Gpr31b-/- islets included those pertaining to receptor signaling, inflammation, oxidative stress, and macrophage migration — effects that are reminiscent of 12-LOX inhibition. Bone-marrow derived macrophages from Gpr31b-/- mice had reduced macrophage migration compared to wildtype macrophages. To mimic islet and macrophage inflammation as seen in T1D, wildtype and Gpr31b-/- mice were treated with the pro-diabetic toxin streptozotocin. Compared to wildtype, Gpr31b-/- mice had improved glucose tolerance and preserved β-cell mass. These results are consistent with previously published data using 12-LOX knockout mice and suggests that GPR31 mediates the proinflammatory responses of 12-HETE in the β cell.
Project description:In type 1 diabetes (T1D), the innate and adaptive immune systems attack and eventually destroy the insulin-secreting islet β cells. During this process, β cells activate inflammatory signaling pathways that augment the dysfunction and destruction imposed by cellular autoimmunity. The 12-lipoxygenase (12-LOX) pathway produces the pro-inflammatory eicosanoid 12-HETE, which induces oxidative and endoplasmic reticulum stress and results in diminished insulin secretion and apoptosis. The G protein-coupled receptor 31 (GPR31) has been identified as a putative receptor for 12-HETE. In this study, we generated conventional GPR31 knockout mice. To interrogate the role of GPR31 in β cells, we treated islets from wildtype and Gpr31b-/- mice with proinflammatory cytokines and subjected the islets to RNA sequencing. Differentially expressed genes in Gpr31b-/- islets included those pertaining to receptor signaling, inflammation, oxidative stress, and macrophage migration — effects that are reminiscent of 12-LOX inhibition. Bone-marrow derived macrophages from Gpr31b-/- mice had reduced macrophage migration compared to wildtype macrophages. To mimic islet and macrophage inflammation as seen in T1D, wildtype and Gpr31b-/- mice were treated with the pro-diabetic toxin streptozotocin. Compared to wildtype, Gpr31b-/- mice had improved glucose tolerance and preserved β-cell mass. These results are consistent with previously published data using 12-LOX knockout mice and suggests that GPR31 mediates the proinflammatory responses of 12-HETE in the β cell.
Project description:We report that the decreased expression of mitochondrial genes we observe in hepatocyte-specific Nampt knockout mice is normalized in primary hepatocytes, and that hepatocyte isolations causes major changes to the hepatocyte transcriptome for both knockouts and wildtype mice.
Project description:GPR31 signaling induced dendrite protrusion of lysozyme-expressing dendritic cells (LysoDCs) into basolateral pockets of M cells. To investigate the effect of GPR31 signaling on LysoDC function during infection, we analyzed the gene expression profile of LysoDCs from WT and Gpr31b-deficient mice at 2 days after L. monocytogenes infection.
Project description:Single-nucleus RNA-seq reveals hepatocyte heterogeneity and progenitor-like populations in Lamtor2-deficient mouse liver Single-nucleus RNA sequencing (snRNA-seq) was performed on whole livers from control mice and from two models of hepatocyte-specific Lamtor2 deletion (a chronic developmental knockout and an acute adult knockout). Unsupervised transcriptomic analysis identified multiple liver cell types and hepatocyte subpopulations, revealing that early (developmental) loss of Lamtor2 triggers the emergence of hepatocytes with a biliary/progenitor-like gene expression signature, whereas acute adult deletion leads to a distinct hepatocyte subcluster with altered metabolic gene expression. These findings highlight hepatocyte plasticity and metabolic reprogramming in Lamtor2-deficient livers, underscoring the crucial role of the Ragulator/mTORC1 signaling complex in maintaining normal hepatocyte identity and function.