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Study of the differential NF-kB activation in beta cells and the mechanisms that can be modulated for the prevention of its pro-apoptotic effect

Abstract

Type 1 diabetes mellitus (T1DM) is an autoimmune disease characterized by the selective destruction of the insulin producing pancreatic beta cells. A better understanding of the molecular mechanisms that regulate apoptosis in beta cells could open new strategies for the treatment (prevention or cure) of this devastating disease. Cytokines such as interleukin (IL)-1b, tumor necrosis factor (TNF)-a and interferon (IFN)-g contribute for pancreatic beta cell death during T1DM. Blocking NF-kB activation prevents cytokine-induced apoptosis in beta cells. This is a surprising finding, since NF-kB has preferentially an anti-apoptotic effect in other cell types. Due to its important role in different cellular responses to a variety of stimulis it is vital to have a better understanding of the specific characteristics that lead to its pro-apoptotic effect, in order to design therapies to prevent beta cell destruction without disturbing cell homeostasis. Previously we showed that NF-kB activation by pro-inflammatory cytokines in beta cells differs in intensity and duration compared to other cell types, and that its induction by IL-1b has a more pronounced pro-apoptotic effect than TNF-a. The differences between IL-1b and TNF-a seems to be related to the higher intensity, induced by IL-1b, in the activation of kinases that modulate NF-kB activation and increase expression of NF-kB-dependent genes that are putatively involved in beta cell dysfunction and death. Recently, we observed that the kinase complex IKK, important for NF-kB activation, is differentially modulated by IL-1b and TNF-a, both quantitatively and qualitative, with IL-1b inducing a differential utilization of IKK members. In the present study we intent to clarify the specific characteristics of NF-kB activation, and the role of the quinases IKKa and IKKb, that lead to a pro-apoptotic effect of this transcription factor in beta cells. To this end, we will use siRNA for the silencing of specific kinases and adaptor proteins with a potential role in NF-kB regulation in insulin producing cell lines and cells from dispersed islets of rodents, and analyze its effect on gene expression, viability and function of these cells after exposure to pro-inflammatory cytokines. The most relevant results will be confirmed in islets from rodent, to analyze the impact of our data in a more complex ambient, where beta cells are exposed to interaction with other cellular types that can also influence its response to injury. After discovery of potential candidates to be used in the prevention of beta cell destruction after an immune assault and/or after islet transplantation, this model will be tested in vivo by the use of animal models of T1DM transplanted with islets KD for key candidate genes. The results obtained in the present project can provide important information for the development of new strategies for genetic intervention for the prevention of beta cell destruction in DM1. (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)
MEYEROVICH, KIRA; ORTIS, FERNANDA; ALLAGNAT, FLORENT; CARDOZO, ALESSANDRA K.. Endoplasmic reticulum stress and the unfolded protein response in pancreatic islet inflammation. JOURNAL OF MOLECULAR ENDOCRINOLOGY, v. 57, n. 1, p. R1-R17, . (10/05587-1)
MEYEROVICH, KIRA; FUKAYA, MAKIKO; TERRA, LETICIA F.; ORTIS, FERNANDA; EIZIRIK, DECIO L.; CARDOZO, ALESSANDRA K.. The non-canonical NF-kappa B pathway is induced by cytokines in pancreatic beta cells and contributes to cell death and proinflammatory responses in vitro. Diabetologia, v. 59, n. 3, p. 512-521, . (10/05587-1)

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