Differential regulation of pro-inflammatory cytokine signalling by protein tyrosine phosphatases in pancreatic β-cells

Bcl-2 and Bcl-xL in Diabetes: Contributions to Endocrine Pancreas Viability and Function

Diabetes is a chronic metabolic disorder whose prevalence increases every year, affecting more than 530 million adults worldwide. Type 1 (T1D) and type 2 diabetes (T2D), the most common forms of diabetes, are characterized by the loss of functional pancreatic β-cells, mostly due to apoptosis. B-cell leukemia/lymphoma 2 (Bcl-2) and B-cell lymphoma-extra large (Bcl-xL), two anti-apoptotic proteins belonging to the Bcl-2 family, are crucial for regulating the intrinsic pathway of apoptosis. However, over the years, they have been implicated in many other cellular processes, including intracellular Ca2+ homeostasis and the regulation of mitochondrial metabolism. Thus, understanding the biological processes in which these proteins are involved may be crucial to designing new therapeutic targets. This review summarizes the roles of Bcl-2 and Bcl-xL in apoptosis and metabolic homeostasis. It focuses on how the dysregulation of Bcl-2 and Bcl-xL affects pancreatic β-cell function and survival, and the consequences for diabetes development.

Applications of Genome-Editing Technologies for Type 1 Diabetes

Type 1 diabetes (T1D) is a chronic autoimmune disease characterized by the destruction of insulin-producing pancreatic β-cells by the immune system. Although conventional therapeutic modalities, such as insulin injection, remain a mainstay, recent years have witnessed the emergence of novel treatment approaches encompassing immunomodulatory therapies, such as stem cell and β-cell transplantation, along with revolutionary gene-editing techniques. Notably, recent research endeavors have enabled the reshaping of the T-cell repertoire, leading to the prevention of T1D development. Furthermore, CRISPR-Cas9 technology has demonstrated remarkable potential in targeting endogenous gene activation, ushering in a promising avenue for the precise guidance of mesenchymal stem cells (MSCs) toward differentiation into insulin-producing cells. This innovative approach holds substantial promise for the treatment of T1D. In this review, we focus on studies that have developed T1D models and treatments using gene-editing systems.

Insulin-Binding Peptide Probes Provide a Novel Strategy for Pancreatic β-Cell Imaging

Type 1 diabetes develops in childhood and adolescence, with peak incidence in the early teenage years. There is an urgent need for an accurate method to detect insulin-producing β-cells in patients that is not affected by alterations in β-cell function. As part of our research program to design specific probes to measure β-cell mass, we recently developed a novel insulin-binding peptide probe (IBPP) for the detection of β-cells in vivo. Here, we applied our innovative method to show specific labeling of this IBPP to human and mouse fixed β-cells in pancreatic islets. Importantly, we showed staining of human and mouse islets in culture without any negative functional or cell viability impact. Moreover, the IBPP-stained mouse islets after tail vein injection in vivo, albeit with batch differences in staining efficiency. In conclusion, we provide evidence showing that the IBPP can be used for future accurate detection of β-cell mass in a variety of preclinical models of diabetes.

Novel Strategies to Protect and Visualize Pancreatic β Cells in Diabetes

A common feature in the pathophysiology of different types of diabetes is the reduction of β cell mass and/or impairment of β cell function. Diagnosis and treatment of type 1 and type 2 diabetes is currently hampered by a lack of reliable techniques to restore β cell survival, to improve insulin secretion, and to quantify β cell mass in patients. Current new approaches may allow us to precisely and specifically visualize β cells in vivo and provide viable therapeutic strategies to preserve, recover, and regenerate β cells. In this review, we discuss recent protective approaches for β cells and the advantages and limitations of current imaging probes in the field.

IL-17F induces inflammation, dysfunction and cell death in mouse islets

Type 17 immune responses, typified by the production of the cytokines IL-17A and IL-17F, have been implicated in the development of type 1 diabetes in animal models and human patients, however the underlying pathogenic mechanisms have not been clearly elucidated. While previous studies show that IL-17A enhances inflammatory gene expression and cell death in mouse β-cells and human islets, the function of IL-17F in pancreatic β-cells is completely untested to date. Here we show that IL-17F exhibits potent pathogenic effects in mouse β-cell lines and islets. IL-17F signals via the IL-17RA and -RC subunits in β-cells and in combination with other inflammatory cytokines induces expression of chemokine transcripts, suppresses the expression of β-cell identity genes and impairs glucose stimulated insulin secretion. Further IL-17F induces cell death in primary mouse islets. This occurs via Jnk, p38 and NF-κB dependent induction of Nos2 and is completely ablated in the presence of an inducible nitric oxide synthase (iNOS) inhibitor. Together these data indicate that IL-17F possesses similar pathogenic activities to IL-17A in mouse β-cell lines and islets and is likely to be a type 17 associated pathogenic factor in type 1 diabetes.