CORM-2 Pretreatment Attenuates Inflammation-mediated Islet Dysfunction.

During the process of human islet isolation a cascade of stressful events are triggered and negatively influence islet yield, viability, and function, including the production of proinflammatory cytokines and activation of apoptosis. Carbon monoxide-releasing molecule 2 (CORM-2) is a donor of carbon monoxide (CO) and can release CO spontaneously. Accumulating studies suggest that CORM-2 exerts cytoprotective and anti-inflammatory properties. However, the effect of CORM-2 on islet isolation is still unclear. In this study, we found that CORM-2 pretreatment significantly decreased the expression of critical inflammatory genes, including tissue factor, intercellular adhesion molecule-1, chemokine (C-C motif) ligand 2, C-X-C motif chemokine 10, Toll-like receptor 4, interleukin-1ß, interleukin-6, and tumor necrosis factor-α (TNF-α). The isolated islets of the CORM-2 pretreatment group showed reduced apoptotic rate, improved viability, and higher glucose-stimulated insulin secretion, and functional gene expression in comparison to control group. Importantly, CORM-2 pretreatment prevented the impairment caused by TNF-α, evidenced by the improved glucose-stimulated index and transplantation outcomes. The present study demonstrated the anti-inflammatory property of CORM-2 during human islet isolation, and we suggest that CORM-2 pretreatment is an appealing treatment to mitigate inflammation-mediated islet dysfunction during isolation and culture ex vivo and to preserve long-term islet survival and function.

Vγ4+ T Cells: A Novel IL-17-Producing γδ T Subsets during the Early Phase of Chlamydial Airway Infection in Mice.

Our previous studies showed that γδ T cells provided immune protection against Chlamydial muridarum (Cm), an obligate intracellular strain of chlamydia trachomatis, lung infection by producing abundant IL-17. In this study, we investigated the proliferation and activation of lung γδ T cell subsets, specifically the IL-17 and IFNγ production by them following Cm lung infection. Our results found that five γδ T cell subsets, Vγ1+ T, Vγ2+ T, Vγ4+ T, Vγ5+ T, and Vγ6+ T, expressed in lungs of naïve mice, while Cm lung infection mainly induced the proliferation and activation of Vγ4+ T cells at day 3 p.i., following Vγ1+ T cells at day 7 p.i. Cytokine detection showed that Cm lung infection induced IFNγ secretion firstly by Vγ4+ T cells at very early stage (day 3) and changed to Vγ1+ T cells at midstage (day 7). Furthermore, Vγ4+ T cell is the main γδ T cell subset that secretes IL-17 at the very early stage of Cm lung infection and Vγ1+ T cell did not secrete IL-17 during the infection. These findings provide in vivo evidence that Vγ4+T cells are the major IL-17 and IFNγ-producing γδ T cell subsets at the early period of Cm lung infection.