title: Riboflavin inhibits IL-6 expression and p38 activation in islet cells.
abstract: Riboflavin is a water-soluble vitamin that reduces the production of proinflammatory mediators and oxygen radicals. Because islet beta-cells are very sensitive to oxidative stress and to cytokines, we investigated the possible cytoprotective effects of riboflavin on insulinoma NIT-1 cells and on isolated rodent islets. NIT-1 cells and islets cultured in the presence or absence of 10 microM riboflavin were studied at baseline and after exposure to cytokines (TNF-alpha, IL-1beta, INF-gamma). Riboflavin treatment did not affect islet cell viability as assessed by flow cytometry for caspases activation. However, riboflavin prevented the cytokine-induced increase in IL-6 mRNA expression and p38 phosphorylation analyzed by real-time PCR and immunoassay, respectively. In summary, nontoxic doses of riboflavin prevent cytokines-induced p38 phosphorylation and IL-6 upregulation in islet cells. This observation, together with the safety profile of riboflavin in the clinical setting, makes it an appealing agent for islet cytoprotection in islet transplantation protocols.
authors: Cell Transplant Center, Diabetes Research Institute, Leonard M. Miller School of Medicine, University of Miami, Miami, FL 33136, USA.
authors: Lorenzo
authors: L
authors: Cobianchi
authors: Alessia
authors: A
authors: Fornoni
authors: Antonello
authors: A
authors: Pileggi
authors: R Damaris
authors: RD
authors: Molano
authors: Nahir Y
authors: NY
authors: Sanabria
authors: Jorge
authors: J
authors: Gonzalez-Quintana
authors: Nicola
authors: N
authors: Bocca
authors: Simona
authors: S
authors: Marzorati
authors: Elsie
authors: E
authors: Zahr
authors: Anthony R
authors: AR
authors: Hogan
authors: Camillo
authors: C
authors: Ricordi
authors: Luca
authors: L
authors: Inverardi
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D003922:Diabetes Mellitus, Type 1 / Q000378:metabolism / Q000628:therapy; D004789:Enzyme Activation / Q000187:drug effects; D015870:Gene Expression / Q000187:drug effects*; D053583:Interleukin-1beta / Q000378:metabolism; D015850:Interleukin-6 / Q000096:biosynthesis*; D007515:Islets of Langerhans / Q000187:drug effects / Q000378:metabolism*; D016381:Islets of Langerhans Transplantation; D008297:Male; D051379:Mice; D016688:Mice, Inbred NOD; D051381:Rats; D012256:Riboflavin / Q000378:metabolism / Q000494:pharmacology*; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism*
chemical_list: D053583:Interleukin-1beta; D015850:Interleukin-6; D014409:Tumor Necrosis Factor-alpha; D048051:p38 Mitogen-Activated Protein Kinases; D012256:Riboflavin