Mesenchymal Stem Cells from Mouse Hair Follicles Inhibit the Development of Type 1 Diabetes.

Mesenchymal stem cells (MSCs) are known for their immunosuppressive properties. Based on the demonstrated anti-inflammatory effect of mouse MSCs from hair follicles (moMSCORS) in a murine wound closure model, this study evaluates their potential for preventing type 1 diabetes (T1D) in C57BL/6 mice. T1D was induced in C57BL/6 mice by repeated low doses of streptozotocin. moMSCORS were injected intravenously on weekly basis. moMSCORS reduced T1D incidence, the insulitis stage, and preserved insulin production in treated animals. moMSCORS primarily exerted immunomodulatory effects by inhibiting CD4+ T cell proliferation and activation. Ex vivo analysis indicated that moMSCORS modified the cellular immune profile within pancreatic lymph nodes and pancreatic infiltrates by reducing the numbers of M1 pro-inflammatory macrophages and T helper 17 cells and upscaling the immunosuppressive T regulatory cells. The proportion of pathogenic insulin-specific CD4+ T cells was down-scaled in the lymph nodes, likely via soluble factors. The moMSCORS detected in the pancreatic infiltrates of treated mice presumably exerted the observed suppressive effect on CD4+ through direct contact. moMSCORS alleviated T1D symptoms in the mouse, qualifying as a candidate for therapeutic products by multiple advantages: non-invasive sampling by epilation, easy access, permanent availability, scalability, and benefits of auto-transplantation.

Development of Type 1 Diabetes in Mice Is Associated with a Decrease in IL-2-Producing ILC3 and FoxP3+ Treg in the Small Intestine.

Recent data indicate the link between the number and function of T regulatory cells (Treg) in the gut immune tissue and initiation and development of autoimmunity associated with type 1 diabetes (T1D). Since type 3 innate lymphoid cells (ILC3) in the small intestine are essential for maintaining FoxP3+ Treg and there are no data about the possible role of ILC3 in T1D pathogenesis, the aim of this study was to explore ILC3-Treg link during the development of T1D. Mature diabetic NOD mice had lower frequencies of IL-2-producing ILC3 and Treg in small intestine lamina propria (SILP) compared to prediabetic NOD mice. Similarly, in multiple low doses of streptozotocin (MLDS)-induced T1D in C57BL/6 mice, hyperglycemic mice exhibited lower numbers of ILC3, IL-2+ ILC3 and Treg in SILP compared to healthy controls. To boost T1D severity, mice were treated with broad-spectrum antibiotics (ABX) for 14 days prior to T1D induction by MLDS. The higher incidence of T1D in ABX-treated mice was associated with significantly lower frequencies of IL-2+ ILC3 and FoxP3+ Treg in SILP compared with mice without ABX treatment. The obtained findings show that the lower proportions of IL-2-expressing ILC3 and FoxP3+ Treg in SILP coincided with diabetes progression and severity.

Ethyl pyruvate ameliorates acute respiratory distress syndrome in mice.

Acute respiratory distress syndrome (ARDS) became a focus of intensive research due to its death toll during the Covid-19 pandemic. An uncontrolled and excessive inflammatory response mediated by proinflammatory molecules such as high mobility group box protein 1 (HMGB1), IL-6, and TNF mounts as a response to infection. In this study, ethyl pyruvate (EP), a known inhibitor of HMGB1, was tested in the model of murine ARDS induced in C57BL/6 mice by intranasal administration of polyinosinic:polycytidylic acid (poly(I:C)). Intraperitoneal administration of EP ameliorated the ARDS-related histopathological changes in the lungs of poly(I:C)-induced ARDS and decreased numbers of immune cells in the lungs, broncho-alveolar lavage fluid and draining lymph nodes (DLN). Specifically, fewer CD8+ T cells and less activated CD4+ T cells were observed in DLN. Consequently, the lungs of EP-treated animals had fewer damage-inflicting CD8+ cells and macrophages. Additionally, the expression and production of proinflammatory cytokines, IL-17, IFN-γ and IL-6 were downregulated in the lungs. The expression of chemokine CCL5 which recruits immune cells into the lungs was also reduced. Finally, EP downregulated the expression of HMGB1 in the lungs. Our results imply that EP should be further evaluated as a potential candidate for ARDS therapy.

ILC3: a case of conflicted identity.

Innate lymphoid cells type 3 (ILC3s) are the first line sentinels at the mucous tissues, where they contribute to the homeostatic immune response in a major way. Also, they have been increasingly appreciated as important modulators of chronic inflammatory and autoimmune responses, both locally and systemically. The proper identification of ILC3 is of utmost importance for meaningful studies on their role in immunity. Flow cytometry is the method of choice for the detection and characterization of ILC3. However, the analysis of ILC3-related papers shows inconsistency in ILC3 phenotypic definition, as different inclusion and exclusion markers are used for their identification. Here, we present these discrepancies in the phenotypic characterization of human and mouse ILC3s. We discuss the pros and cons of using various markers for ILC3 identification. Furthermore, we consider the possibilities for the efficient isolation and propagation of ILC3 from different organs and tissues for in-vitro and in-vivo studies. This paper calls upon uniformity in ILC3 definition, isolation, and propagation for the increased possibility of confluent interpretation of ILC3's role in immunity.

Defining the ferroptotic phenotype of beta cells in type 1 diabetes and its inhibition as a potential antidiabetic strategy.

Introduction: Recently, the involvement of ferroptotic cell death in the reduction of ß-cell mass in diabetes has been demonstrated. To elucidate the mechanisms of ß-cell ferroptosis and potential antidiabetic effects of the ferroptosis inhibitor ferrostatin-1 (Fer-1) in vivo, a mouse model of type 1 diabetes (T1D) was used. Methods: Animals were divided into three groups: control (vehicle-treated), diabetic (streptozotocin-treated, 40 mg/kg, from days 1-5), and diabetic treated with Fer-1 (1 mg/kg, from days 1-21). On day 22, glycemia and insulinemia were measured and pancreases were isolated for microscopic analyses. Results: Diabetes disturbed general parameters of ß-cell mass (islet size, ß-cell abundance and distribution) and health (insulin and PDX-1 expression), increased lipid peroxidation in islet cells, and phagocytic removal of iron-containing material. It also downregulated the main players of the antiferroptotic pathway - Nrf2, GPX4, and xCT. In contrast, Fer-1 ameliorated the signs of deterioration of ß-cell/islets, decreased lipid peroxidation, and reduced phagocytic activity, while upregulated expression of Nrf2 (and its nuclear translocation), GPX4, and xCT in ß-cell/islets. Discussion: Overall, our study confirms ferroptosis as an important mode of ß-cell death in T1D and suggests antiferroptotic agents as a promising strategy for the prevention and treatment of diabetes.