Project description:Immune-mediated destruction of insulin-producing β-cells causes type 1 diabetes (T1D). However, how β-cells themselves participate in the disease process is poorly understood. Here, we report that modulating the unfolded protein response (UPR) in β-cells of non-obese diabetic (NOD) mice in early stages of disease results in preserved β-cell function, substantially reduced islet immune cell infiltration, and β-cell apoptosis leading to protection from T1D. NOD mice that lack the UPR sensor IRE1α in β-cells show greatly reduced expression of β-cell identity markers, islet autoantigens, and genes involved in antigen presentation. These mice exhibit upregulation of immune inhibitory markers in β-cells and significantly less cytotoxic CD8+ T cells in the pancreas. Our results indicate that triggering transient β-cell dedifferentiation via targeting a specific branch of the UPR in β-cells, prior to insulitis, allow β-cells to escape from immune destruction and may be used as a novel preventive strategy for high-risk individuals.
Project description:Immune-mediated destruction of insulin-producing β-cells causes type 1 diabetes (T1D). However, how β-cells themselves participate in the disease process is poorly understood. Here, we report that modulating the unfolded protein response (UPR) in β-cells of non-obese diabetic (NOD) mice in early stages of disease results in preserved β-cell function, substantially reduced islet immune cell infiltration, and β-cell apoptosis leading to protection from T1D. NOD mice that lack the UPR sensor IRE1α in β-cells show greatly reduced expression of β-cell identity markers, islet autoantigens, and genes involved in antigen presentation. These mice exhibit upregulation of immune inhibitory markers in β-cells and significantly less cytotoxic CD8+ T cells in the pancreas. Our results indicate that triggering transient β-cell dedifferentiation via targeting a specific branch of the UPR in β-cells, prior to insulitis, allow β-cells to escape from immune destruction and may be used as a novel preventive strategy for high-risk individuals.
Project description:Immune-mediated destruction of insulin-producing β cells causes type 1 diabetes (T1D). However, how β cells participate in their own destruction during the disease process is poorly understood. Here, we report that modulating the unfolded protein response (UPR) in β cells of non-obese diabetic (NOD) mice by deleting the UPR sensor IRE1α prior to insulitis induced a transient dedifferentiation of β cells, resulting in substantially reduced islet immune cell infiltration and β cell apoptosis. Single-cell and whole-islet transcriptomics analyses of immature β cells revealed remarkably diminished expression of β cell autoantigens and MHC class I components, and upregulation of immune inhibitory markers. IRE1α-deficient mice exhibited significantly fewer cytotoxic CD8+ T cells in their pancreata, and adoptive transfer of their total T cells did not induce diabetes in Rag1-/- mice. Our results indicate that inducing β cell dedifferentiation, prior to insulitis, allows these cells to escape immune-mediated destruction and may be used as a novel preventive strategy for T1D in high-risk individuals.
Project description:Type 1 diabetes (T1D) is characterized by pancreatic islet infiltration by autoreactive immune cells and a near-total loss of β-cells. Restoration of insulin-producing β-cells coupled with immunomodulation to suppress the autoimmune attack has emerged as a potential approach to counter T1D. Here we report that enhancing β-cell mass in female NOD mice early in life (prior to weaning) results in immunomodulation of T-cells, reduced islet infiltration and lower β-cell apoptosis, that together protect them from developing T1D. We observed that a model exhibiting β-cell hyperplasia on the NOD background (NOD-LIRKO) displayed altered β-cell antigens, and islet transplantation studies showed prolonged graft survival of NOD-LIRKO islets even upon exposure to diabetogenic splenocytes in vivo. Adoptive transfer of splenocytes from the NOD-LIRKOs prevented diabetes development in pre-diabetic NOD mice, while conversely, similar protective outcomes were obtained when NOD-LIRKO splenocytes were adoptively transferred after mixing them with diabetogenic NOD splenocytes in a dose-dependent manner. A significant increase in the splenic CD4+CD25+FoxP3+ regulatory T-cell (Treg) population in the NOD-LIRKO mice was observed to drive the protected phenotype since Treg depletion rendered NOD-LIRKO mice diabetic. The increase in Tregs coupled with a downregulation of key mediators of cellular function, upregulation of apoptosis and activation of TGF-β/SMAD3 signaling pathway in pathogenic T-cells favored reduced ability to kill β-cells. These data provide novel evidence that initiating β-cell proliferation, alone, prior to islet infiltration by immune cells alters the identity of β-cells, decreases pathologic self-reactivity of effector cells and increases Tregs to prevent progression of T1D.
Project description:Type 1 diabetes (T1D) is characterized by pancreatic islet infiltration by autoreactive immune cells and a near-total loss of β-cells1. Restoration of insulin-producing β-cells coupled with immunomodulation to suppress the autoimmune attack has emerged as a potential approach to counter T1D2-4. Here we report that enhancing β-cell mass early in life, in two models of female NOD mice, results in immunomodulation of T-cells, reduced islet infiltration and lower β-cell apoptosis, that together protect them from developing T1D. The animals displayed altered β-cell antigens, and islet transplantation studies showed prolonged graft survival in the NOD-LIRKO model. Adoptive transfer of splenocytes from the NOD-LIRKOs prevented development of diabetes in pre-diabetic NOD mice. A significant increase in the splenic CD4+CD25+FoxP3+ regulatory T-cell (Treg) population was observed to underlie the protected phenotype since Treg depletion rendered NOD-LIRKO mice diabetic. The increase in Tregs coupled with activation of TGF-β/SMAD3 signaling pathway in pathogenic T-cells favored reduced ability to kill β-cells. These data support a previously unidentified observation that initiating β-cell proliferation, alone, prior to islet infiltration by immune cells alters the identity of β-cells, decreases pathologic self-reactivity of effector cells and increases Tregs to prevent progression of T1D.
Project description:Modern lifestyles have altered diet and metabolic homeostasis, with increased sugar intake, glycemic index, and prediabetes. A strong positive correlation between sugar consumption and diabetic incidence is revealed, but the underlying mechanisms remain obscure. Here we show that oral intake of long-term oscillating glucose (LOsG) (4 times/day) for 38 days, which produces physiological glycemic variability in rats, can lead to β-cells gaining metabolic memory in reactive oxygen species (ROS) stress. This stress leads to suppression of forkhead box O1 (FoxO1) signaling and subsequent upregulation of thioredoxin interacting protein, inhibition of insulin and SOD-2 expression, re-expression of Neurog3, and β-cell dedifferentiation and functional failure. LOsG-treated animals develop prediabetes exhibiting hypoinsulinemia and glucose intolerance. Dynamic and timely administration of antioxidant glutathione prevents LOsG/ROS-induced β-cell failure and prediabetes. We propose that ROS stress is the initial step in LOsG-inducing prediabetes. Manipulating glutathione-related pathways may offer novel options for preventing the occurrence and development of diabetes.