Vascularized Macrophage-Islet Organoids to Model Immune-Mediated Pancreatic beta cell Pyroptosis upon Viral Infection [scRNAseq.islets]

Immune cells play critical roles in causing host damage in various diseases, including infectious diseases. However, there is a paucity of human models to study immune-mediated host damage. Here, we systematically analyzed the changes in immune cell composition for COVID-19 pancreatic autopsy samples using the GeoMx spatial RNA and protein platform and found accumulation of proinflammatory macrophages. Single cell RNA-seq analysis of human islets upon SARS-CoV-2 or Coxsackievirus B4 (CVB4) infection identified the activation of proinflammatory macrophages and pyroptosis in β cells. To distinguish whether the virus or proinflammatory macrophages mediated β cell pyroptosis, we developed human pluripotent stem cell (hPSC)-derived vascularized macrophage-islet (VMI) organoids, containing pancreatic endocrine cells, endothelial cells, and macrophages. Both pancreatic β cells and endothelial cells in VMI organoids demonstrated improved marker expression and function compared to separately cultured cells. Additionally, proinflammatory macrophages in VMI organoids were found to induce β cell pyroptosis. Further mechanistic studies identified TNFSF12-TNFRSF12A as a contributor to proinflammatory macrophage-mediated β cell pyroptosis. Together, this study established a hPSC-derived VMI organoid as a valuable tool for studying immune cell-mediated host damage and uncovered previous unknown mechanism of β cell damage in viral infection.