@article {1817, title = {Trail down-regulates the release of osteoprotegerin (OPG) by primary stromal cells.}, journal = {J Cell Physiol}, volume = {226}, year = {2011}, month = {2011 Sep}, pages = {2279-86}, abstract = {

The soluble member of the TNF-R superfamily osteoprotegerin (OPG) is abundantly released under basal conditions by both mesenchymal stem cells (MSC) and fibroblasts and by endothelial cells upon stimulation with inflammatory cytokines. Since MSC, fibroblasts and endothelial cells represent key elements of the normal and tumor microenvironment and express detectable levels of surface TRAIL receptors, we investigated the effect of TRAIL on OPG release. Unexpectedly, recombinant TRAIL decreased the spontaneous OPG release in all cell types examined. Moreover, TRAIL decreased OPG release also in stromal cells co-cultured with lymphoma cells and counteracted the OPG induction by TN-alpha in HUVEC and MSC. Such down-regulation was not due to a masking effect in the ELISA quantification of the OPG released in the culture supernatants due to binding of OPG to its ligands (TRAIL and RANKL), as demonstrated by competition experiments with recombinant TRAIL and by the lack of RANKL release/induction. In addition, OPG down-regulation was not due to induction of cytotoxic effects by TRAIL, since the degree of apoptosis in response to TRAIL was negligible in all primary cell types. With regards to the possible molecular mechanism accounting for the down-regulation of OPG release by TRAIL, we found that treatment of MSC with TRAIL significantly decreased the phosphorylation levels of p38/MAPK. There is a suggestion that this pathway is involved in the stabilization of OPG mRNA. In this respect, the ability of TRAIL to decrease the release of OPG, in the absence of cell cytotoxicity, was mimicked by the p38/MAPK inhibitor SB203580.

}, keywords = {Bone Marrow Cells, Cell Death, Cells, Cultured, Coculture Techniques, Down-Regulation, Endothelial Cells, Enzyme Activation, Enzyme-Linked Immunosorbent Assay, Fibroblasts, Humans, MAP Kinase Signaling System, Mesenchymal Stromal Cells, Osteoprotegerin, p38 Mitogen-Activated Protein Kinases, Protein Binding, Recombinant Proteins, Stromal Cells, TNF-Related Apoptosis-Inducing Ligand, Tumor Necrosis Factor-alpha}, issn = {1097-4652}, doi = {10.1002/jcp.22564}, author = {Corallini, Federica and Celeghini, Claudio and Rimondi, Erika and di Iasio, Maria Grazia and Gonelli, Arianna and Secchiero, Paola and Zauli, Giorgio} } @article {1718, title = {Treatment with recombinant tumor necrosis factor-related apoptosis-inducing ligand alleviates the severity of streptozotocin-induced diabetes.}, journal = {Diabetes}, volume = {59}, year = {2010}, month = {2010 May}, pages = {1261-5}, abstract = {

OBJECTIVE: To evaluate the potential therapeutic effect of recombinant human tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) treatment in a model of type 1 diabetes.

RESEARCH DESIGN AND METHODS: Recombinant TRAIL was added in vitro to primary human and mouse peripheral blood mononuclear cells (PBMCs) and isolated human islets to evaluate the expression of the immunoregulatory gene SOCS1. Diabetes was induced by five consecutive daily injections of low-concentration (50 mg/kg) streptozotocin (STZ) in C57 black mice (n = 24). A group of these mice (n = 12) was co-injected with recombinant TRAIL (20 microg/day) for 5 days, and the diabetic status (glycemia and body weight) was followed over time. After 6 weeks, circulating levels of insulin, TNF-alpha, and osteoprotegerin (OPG) were measured, and animals were killed to perform the histological analysis of the pancreas.

RESULTS: The in vitro exposure of both PBMCs and human islets to recombinant TRAIL significantly upregulated the expression of SOCS1. With respect to STZ-treated animals, mice co-injected with STZ+TRAIL were characterized by 1) lower levels of hyperglycemia, 2) higher levels of body weight and insulinemia, 3) a partial preservation of pancreatic islets with normal morphology, and 4) a lower expression of both systemic (TNF-alpha and OPG) and pancreatic (vascular cell adhesion molecule [VCAM]-1) inflammatory markers.

CONCLUSIONS: Overall, these data demonstrate that the administration of recombinant TRAIL ameliorates the severity of STZ-induced type 1 diabetes, and this effect was accompanied by the upregulation of SOCS1 expression.

}, keywords = {Animals, Cells, Cultured, Diabetes Mellitus, Experimental, Gene Expression, Humans, Islets of Langerhans, Leukocytes, Mononuclear, Mice, Recombinant Proteins, Suppressor of Cytokine Signaling Proteins, TNF-Related Apoptosis-Inducing Ligand}, issn = {1939-327X}, doi = {10.2337/db09-1771}, author = {Zauli, Giorgio and Toffoli, Barbara and di Iasio, Maria Grazia and Celeghini, Claudio and Fabris, Bruno and Secchiero, Paola} }