PIEZO1 mediates a mechanothrombotic pathway in diabetes.

Thrombosis is the leading complication of common human disorders including diabetes, coronary heart disease, and infection and remains a global health burden. Current anticoagulant therapies that target the general clotting cascade are associated with unpredictable adverse bleeding effects, because understanding of hemostasis remains incomplete. Here, using perturbational screening of patient peripheral blood samples for latent phenotypes, we identified dysregulation of the major mechanosensory ion channel Piezo1 in multiple blood lineages in patients with type 2 diabetes mellitus (T2DM). Hyperglycemia activated PIEZO1 transcription in mature blood cells and selected high Piezo1­expressing hematopoietic stem cell clones. Elevated Piezo1 activity in platelets, red blood cells, and neutrophils in T2DM triggered discrete prothrombotic cellular responses. Inhibition of Piezo1 protected against thrombosis both in human blood and in zebrafish genetic models, particularly in hyperglycemia. Our findings identify a candidate target to precisely modulate mechanically induced thrombosis in T2DM and a potential screening method to predict patient-specific risk. Ongoing remodeling of cell lineages in hematopoiesis is an integral component of thrombotic risk in T2DM, and related mechanisms may have a broader role in chronic disease.

CCL21 Expression in ß-Cells Induces Antigen-Expressing Stromal Cell Networks in the Pancreas and Prevents Autoimmune Diabetes in Mice.

Tumors induce tolerance toward their antigens by producing the chemokine CCL21, leading to the formation of tertiary lymphoid organs (TLOs). Ins2-CCL21 transgenic, nonobese diabetic (NOD) mice express CCL21 in pancreatic ß-cells and do not develop autoimmune diabetes. We investigated by which mechanisms CCL21 expression prevented diabetes. Ins2-CCL21 mice develop TLOs by 4 weeks of age, consisting of naive CD4+ T cells compartmentalized within networks of CD45-gp38+CD31- fibroblastic reticular cell (FRC)-like cells. Importantly, 12-week-old Ins2-CCL21 TLOs contained FRC-like cells with higher contractility, regulatory, and anti-inflammatory properties and enhanced expression of ß-cell autoantigens compared with nontransgenic NOD TLOs found in inflamed islets. Consistently, transgenic mice harbored fewer autoreactive T cells and a higher proportion of regulatory T cells in the islets. Using adoptive transfer and islet transplantation models, we demonstrate that TLO formation in Ins2-CCL21 transgenic islets is critical for the regulation of autoimmunity, and although the effect is systemic, the induction is mediated locally likely by lymphocyte trafficking through TLOs. Overall, our findings suggest that CCL21 promotes TLOs that differ from inflammatory TLOs found in type 1 diabetic islets in that they resemble lymph nodes, contain FRC-like cells expressing ß-cell autoantigens, and are able to induce systemic and antigen-specific tolerance leading to diabetes prevention.