Bovine Monocyte Chemotactic Protein 3 ELISA Kit

The link between the extensive usage of calcineurin (CN) inhibitors cyclosporin A and tacrolimus (FK506) in transplantation medicine and the increasing rate of opportunistic infections within this segment of patients is alarming. Currently, how peritoneal infections are favored by these drugs, which impair the activity of several signaling pathways including the Ca++/CN/NFAT, Ca++/CN/cofilin, Ca++/CN/BAD, and NF-kappa B networks, is unknown. Here, we show that Saccharomyces cerevisiae infection of peritoneal resident macrophages triggers the transient nuclear translocation of NFATc1 beta isoforms, resulting in a coordinated, CN-dependent induction of the Ccl2, Ccl7, and Ccl12 genes, all encoding CCR2 agonists. CN inhibitors block the CCR2-dependent recruitment of inflammatory monocytes (IM) to the peritoneal cavities of S. cerevisiae infected mice. In myeloid cells, NFATc1/beta proteins represent the most prominent NFATc1 isoforms. NFATc1/beta ablation leads to a decrease of CCR2 chemokines, impaired mobilization of IMs, and delayed clearance of infection. We show that, upon binding to a composite NFAT/BCL6 regulatory element within the Ccl2 promoter, NFATc1/beta proteins release the BCL6-dependent repression of Ccl2 gene in macrophages. These findings suggest a novel CN-dependent cross-talk between NFAT and BCL6 transcription factors, which may affect the outcome of opportunistic fungal infections in immunocompromised patients.

Type 1 diabetes is an autoimmune disease initiated by the invasion of pancreatic islets by immune cells that selectively kill the beta cells. We found that rodent and human T lymphocytes release exosomes containing the microRNAs (miRNAs) miR-142-3p, miR-142-5p, and miR-155, which can be transferred in active form to beta cells favoring apoptosis. Inactivation of these miRNAs in recipient beta cells prevents exosome-mediated apoptosis and protects non-obese diabetic (NOD) mice from diabetes development. Islets from protected NOD mice display higher insulin levels, lower insulitis scores, and reduced inflammation. Looking at the mechanisms underlying exosome action, we found that T lymphocyte exosomes trigger apoptosis and the expression of genes involved in chemokine signaling, including Ccl2, Ccl7, and Cxcl10, exclusively in beta cells. The induction of these genes may promote the recruitment of immune cells and exacerbate beta cell death during the autoimmune attack. Our data point to exosomal-miRNA transfer as a communication mode between immune and insulin-secreting cells.