Serum amyloid A effects in the pancreatic ²-cell

• Grant number: 11/19589-9
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: December 01, 2011
• End date: December 31, 2014
• Field of knowledge: Biological Sciences - Pharmacology - Biochemical and Molecular Pharmacology
• Principal Investigator: Elaine Hatanaka Dermargos
• Grantee: Maysa Braga Barros Silva
• Host Institution: Pró-Reitoria de Pós-Graduação e Pesquisa. Universidade Cruzeiro do Sul (UNICSUL). São Paulo , SP, Brazil

Abstract

Inflammation plays a key role in the development of ²-cell dysfunction that is associated with loss of glucose-stimulated insulin secretion, reduction in ²-cell mass, and insulin resistance. Decreased insulin secretion by pancreatic ²-cells may be caused by amyloid deposition or lipotoxicity. Serum amyloid A (SAA), a classical acute phase protein, plays a role in the inflammatory process by increasing the production of inflammatory mediators. During the acute phase response, SAA can displace apoA-I from HDL. Because of the association of apoA-I with HDL particles, SAA was thought to be involved in lipid metabolism, altering fatty acid levels. Persistently elevated SAA levels characterize a number of metabolic disorders, such as obesity. The biological effects of this protein are far from being completely understood despite SAA's role in most forms of inflammation, infection, and tissue damage. We hypothesize that chronic pancreatic exposure to SAA may lead to alterations in insulin secretion by inflammatory/oxidative mechanisms. Thus, the purpose of this study is to investigate the effects of SAA on the function of pancreatic ²-cells. To define the toxic dose of SAA in ²-cells, we will assay (a) DNA fragmentation, (b) membrane integrity, and (c) reactive oxygen species release. DNA fragmentation and membrane integrity will be assessed by flow cytometry. The effect of SAA on the production of ROS by pancreatic ² cells will be investigated using luminol, lucigenin amplified chemiluminescence, hydroethidine, and phenol red reduction. We will later seek to verify the expression and release of cytokines (TNF-±, IL-1², IL-8, and IL-6) by qPCR and ELISA, respectively. Additionally, we will monitor the release of insulin.(AU)