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Involvement of NADPH oxidase isoforms in the dysfunction of insulin secreting cells exposed to pro-inflammatory cytokines


Diabetes mellitus is characterized by failures in the action and/or the production of insulin, which leads to the inability to maintain glycemic homeostasis. Type 1 diabetes is characterized by inflammation of the pancreatic islets (insulitis) causing dysfunction and death of the islet cells. Local production of pro-inflammatory cytokines, such as IL-1², TNF-± and IFN-³, is directly related to beta cells apoptosis due to an increased production of reactive oxygen (ROS) and nitrogen species that induce endoplasmic reticulum stress and increased unfolded protein response (UPR). EROs may be produced, among other sources, by the enzyme NADPH oxidase, which is a superoxide producing enzyme complex formed by membrane and cytosolic subunits. The catalytic core of the enzyme (gp91phox or NOX-2) has several homologs, such as NOX-1. Recent evidence indicates the involvement of NOX-1 in beta cell dysfunction during exposure to cytokines. However, the use of nonspecific NADPH oxidase inhibitors and the expression of different isoforms in the islet has been a limitation for the confirmation of the results obtained up to now. Thus, the relationship between NADPH oxidase and reticulum stress in pancreatic beta cells has been explored in recent years, but still requires further investigation. In this way, we intend to evaluate the importance of NADPH oxidase enzymes, more specifically NOX-1 and NOX-2, in pancreatic beta cells exposed to proinflammatory cytokines and analyze cell viability, endoplasmic reticulum stress, production of reactive oxygen species and insulin secretion. Therefore, we will utilize INS-1E cells treated with iRNA against NOX-1 or NOX-2 or treated with ML171 (a NOX-1 pharmacological inhibitor) and islets isolated from NOX-1 or NOX-2 knockout mice. Both the cell line and the islets of the animals will be maintained in culture and exposed to a mix of proinflammatory cytokines (IL-1² + TNF-± + IFN-³) for the evaluation of the processes described above. (AU)

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Scientific publications
(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)
VILAS-BOAS, ELOISA A.; CARLEIN, CHRISTOPHER; NALBACH, LISA; ALMEIDA, DAVIDSON C.; AMPOFO, EMMANUEL; CARPINELLI, ANGELO R.; ROMA, LETICIA P.; ORTIS, FERNANDA. Early Cytokine-Induced Transient NOX2 Activity Is ER Stress-Dependent and Impacts beta-Cell Function and Survival. ANTIOXIDANTS, v. 10, n. 8, . (17/26339-5, 20/06184-0, 17/04580-2, 13/08769-1)
VILAS-BOAS, ELOISA APARECIDA; NALBACH, LISA; AMPOFO, EMMANUEL; LUCENA, CAMILA FERRAZ; NAUDET, LEA; ORTIS, FERNANDA; CARPINELLI, ANGELO RAFAEL; MORGAN, BRUCE; ROMA, LETICIA PRATES. Transient NADPH oxidase 2-dependent H2O2 production drives early palmitate-induced lipotoxicity in pancreatic islets. Free Radical Biology and Medicine, v. 162, . (13/08769-1, 17/26339-5, 09/51893-0, 11/04511-4)
VILAS-BOAS, ELOISA APARECIDA; ALMEIDA, DAVIDSON CORREA; ROMA, LETICIA PRATES; ORTIS, FERNANDA; CARPINELLI, ANGELO RAFAEL. Lipotoxicity and beta-Cell Failure in Type 2 Diabetes: Oxidative Stress Linked to NADPH Oxidase and ER Stress. CELLS, v. 10, n. 12, . (17/26339-5, 17/04580-2, 19/26062-9, 14/50867-3, 20/06184-0)

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