Project description:Anti-CD3 mAb delays or prevents type 1 diabetes (T1D) by modulating the immune mediated destruction of beta cells. Our findings described the reshaping of islet-infiltrating T cells and beta cells that lead to operational, but tenuous tolerance to autoimmune diabetes following anti-CD3 mAb treatment.
Project description:Type 1 diabetes (T1D) results from autoimmune destruction of β cells in the pancreas. Protein tyrosine phosphatases (PTPs) are candidate genes for T1D and play a key role in autoimmune disease development and β-cell function. Here, we assessed the global protein and individual PTP profile in the pancreas of diabetic NOD mice treated with anti-CD3 mAb and IL-1RA combination therapy. The treatment reversed hyperglycemia compared to the anti-CD3 alone control group. We observed enhanced expression of PTPN2, a T1D candidate gene, and endoplasmic reticulum (ER) chaperones in the islets from cured mice.
Project description:Type 1 diabetes (T1D) results from autoimmune destruction of β-cells in the pancreas. Protein tyrosine phosphatases (PTPs) are candidate genes for T1D and play a key role in autoimmune disease development and β-cell function. Here, we assessed the global protein and individual PTP profile in the pancreas from diabetic NOD mice treated with anti-CD3 monoclonal antibody and IL-1 receptor antagonist (IL-1RA). The treatment reversed hyperglycemia compared to the anti-CD3 alone control group. We observed enhanced expression of PTPN2, a T1D candidate gene, and endoplasmic reticulum (ER) chaperones in islets from mice with reversed diabetes. To address the functional role of PTPN2 in β-cells, we generated PTPN2 deficient stem cell-derived β-like and human EndoC-βH1 cells. Mechanistically, we demonstrated that PTPN2 inactivation in β-cells exacerbates the type I and type II IFN signalling networks, and the potential progression towards autoimmunity. Moreover, we established the capacity of PTPN2 to modulate the Ca2+-dependent unfolded protein response in β-cells. Adenovirus-induced overexpression of PTPN2 decreased BiP expression and partially protected from ER-stress induced β-cell death. Our results postulate PTPN2 as a key protective factor in β-cells during inflammation and ER stress in autoimmune diabetes.
Project description:Several clinical trials have shown anti-CD3 treatment to be a promising therapy for autoimmune diabetes, but its mechanism of action remains unclear. Foxp3+ regulatory T (Treg) cells are likely to be involved, and we have shown a strong effect of anti-CD3 on homeostatic control of CD4+ FoxP3+ regulatory T (Treg) cells. To analyze the early consequences of anti-CD3 treatment, we sorted and profiled Treg and conventional CD4+ T (Tconv) cells in the first hours and days after anti-CD3 treatment of NOD mice. In practice, NOD mice carrying the Foxp3-GFP reporter were treated with anti-CD3 mAb KT3 (50 ug iv) and CD4+ T cells were sorted from pooled spleen and lymph nodes after 2, 8, 24 and 72 hrs, separating Treg and Tconv cells on the basis of GFP expression. Anti-CD3 treatment led to a transient transcriptional response, terminating faster than most antigen-induced responses. Most transcripts were similarly induced in Treg and Tconv cells, but several were differential, in particular those encoding the IL7 receptor (IL7R) and transcription factors Id2/3 and Gfi1, upregulated in Treg but repressed in Tconv cells. In parallel experiments, we tested the effect of soluble anti-CD3 added to cultures of fresh splenocytes, sorting Treg and Tconv cells at the same time points. Many of the anti-CD3 elicited changes, and of the differential response observed in vivo, were also observed in vitro. Two independent replicate series; Treg and Tconv samples abbreviated TR and TC, respectively. Keywords: Transcriptional activation, TCR All gene expression profiles were obtained from highly purified T cell populations sorted by flow cytometry. RNA from 5 x 104 cells was amplified, labeled, and hybridized to Affymetrix ST1.0 Gene arrays. Raw data were preprocessed with the RMA algorithm in GenePattern, and averaged expression values were used for analysis.
Project description:Several clinical trials have shown anti-CD3 treatment to be a promising therapy for autoimmune diabetes, but its mechanism of action remains unclear. Foxp3+ regulatory T (Treg) cells are likely to be involved, and we have shown a strong effect of anti-CD3 on homeostatic control of CD4+ FoxP3+ regulatory T (Treg) cells. To analyze the early consequences of anti-CD3 treatment, we sorted and profiled Treg and conventional CD4+ T (Tconv) cells in the first hours and days after anti-CD3 treatment of NOD mice. In practice, NOD mice carrying the Foxp3-GFP reporter were treated with anti-CD3 mAb KT3 (50 ug iv) and CD4+ T cells were sorted from pooled spleen and lymph nodes after 2, 8, 24 and 72 hrs, separating Treg and Tconv cells on the basis of GFP expression. Anti-CD3 treatment led to a transient transcriptional response, terminating faster than most antigen-induced responses. Most transcripts were similarly induced in Treg and Tconv cells, but several were differential, in particular those encoding the IL7 receptor (IL7R) and transcription factors Id2/3 and Gfi1, upregulated in Treg but repressed in Tconv cells. In parallel experiments, we tested the effect of soluble anti-CD3 added to cultures of fresh splenocytes, sorting Treg and Tconv cells at the same time points. Many of the anti-CD3 elicited changes, and of the differential response observed in vivo, were also observed in vitro. Two independent replicate series; Treg and Tconv samples abbreviated TR and TC, respectively. Keywords: Transcriptional activation, TCR
Project description:Appropriate tuning of protein homeostasis through mobilization of the unfolded protein response (UPR) is key to the capacity of pancreatic beta cells to cope with highly variable demand for insulin synthesis. An efficient UPR ensures a sufficient beta cell mass and secretory output but can also affect beta cell resilience to autoimmune aggression. However, the factors regulating protein homeostasis in the face of metabolic and immune challenges are insufficie tly understood. We examined beta cell adaptation to stress in mice deficient for insulin-degrading enzyme (IDE), a ubiquitous protease with high affinity for insulin, a putative ill-defined role in protein homeostasis, and genetic association with type 2 diabetes. IDE deficiency induces a low-level UPR in both standard and autoimmune non-obese diabetic (NOD) mice, associated with rapamycin-sensitive beta cell proliferation, as well as protection from diabetes in NOD mice. Moreover, in NOD islets, IDE deficiency specifically induces strong upregulation of regenerating islet-derived protein 2, a protein attenuating inflammation and protecting from autoimmunity. Our findings establish a role of IDE in islet cell protein homeostasis, corroborate the link between low-level UPR and proliferation, and identify an anti-inflammatory islet cell response uncovered in the absence of IDE of potential interest in autoimmune diabetes.
Project description:Checkpoint inhibitors (CPIs) targeting PD-1/PD-L1 and CTLA-4 have revolutionized cancer treatment but can trigger autoimmune complications including CPI-induced diabetes (CPI-DM), which occurs preferentially with PD-1 blockade. We found evidence of pancreatic inflammation in patients with CPI-DM with shrinkage of pancreases, increased pancreatic enzymes, and in a case from a patient who died with CPI-DM, peri-islet lymphocytic infiltration. In the NOD mouse model, anti-PD-L1 but not anti-CTLA-4 induces DM rapidly. RNA sequencing revealed that cytolytic IFNγ+ CD8+ T cells infiltrated islets with anti-PD-L1. Changes in β cells were predominantly driven by IFNγ and TNFα and included induction of a novel β cell population with transcriptional changes suggesting dedifferentiation. IFNγ increased checkpoint ligand expression and activated apoptosis pathways in human β cells in vitro. Treatment with anti-IFNγ and anti-TNFα prevented CPI-DM in anti-PD-L1 treated NOD mice. CPIs targeting the PD-1/PD-L1 pathway result in transcriptional changes in β cells and immune infiltrates that may lead to the development of diabetes. Inhibition of inflammatory cytokines can prevent CPI-DM, suggesting a strategy for clinical application to prevent this complication.
Project description:Checkpoint inhibitors (CPIs) targeting PD-1/PD-L1 and CTLA-4 have revolutionized cancer treatment but can trigger autoimmune complications including CPI-induced diabetes (CPI-DM), which occurs preferentially with PD-1 blockade. We found evidence of pancreatic inflammation in patients with CPI-DM with shrinkage of pancreases, increased pancreatic enzymes, and in a case from a patient who died with CPI-DM, peri-islet lymphocytic infiltration. In the NOD mouse model, anti-PD-L1 but not anti-CTLA-4 induces DM rapidly. RNA sequencing revealed that cytolytic IFNγ+ CD8+ T cells infiltrated islets with anti-PD-L1. Changes in β cells were predominantly driven by IFNγ and TNFα and included induction of a novel β cell population with transcriptional changes suggesting dedifferentiation. IFNγ increased checkpoint ligand expression and activated apoptosis pathways in human β cells in vitro. Treatment with anti-IFNγ and anti-TNFα prevented CPI-DM in anti-PD-L1 treated NOD mice. CPIs targeting the PD-1/PD-L1 pathway result in transcriptional changes in β cells and immune infiltrates that may lead to the development of diabetes. Inhibition of inflammatory cytokines can prevent CPI-DM, suggesting a strategy for clinical application to prevent this complication.
Project description:Senescence in pancreatic beta cells plays a major role in beta cell dysfunction which leads to impaired glucose homeostasis and diabetes. Therefore, prevention of beta cell senescence could reduce the risk of diabetes. Treatment of NOD mice, a model of Type 1 autoimmune diabetes (T1D), with Palmitic acid hydroxy stearic acids (PAHSAs), a novel class of endogenous lipids with antidiabetic and anti-inflammatory effects, delays the onset and reduces the incidence of T1D from 82% with vehicle treatment to 35% with PAHSAs. Here we show that a major mechanism by which PAHSAs protect islets of the NOD mice is by directly preventing and reversing the initial steps of metabolic stress-induced senescence. In vitro PAHSAs increased Mdm2 expression, which decreases the stability of p53, a key inducer of senescence-related genes. In addition, PAHSAs enhanced expression of protective genes, such as those regulating DNA repair and glutathione metabolism, and promoting autophagy. We demonstrate the translational relevance by showing that PAHSAs prevent and reverse early stages of senescence in metabolically-stressed human islets by the same Mdm2 mechanism. Thus, a major mechanism for the dramatic effect of PAHSAs to reduce the incidence of Type 1 diabetes in NOD mice is by decreasing cellular senescence; PAHSAs may have a similar benefit in humans.