| Grant number: | 09/53869-9 |
| Support Opportunities: | Regular Research Grants |
| Start date: | May 01, 2010 |
| End date: | October 31, 2012 |
| Field of knowledge: | Health Sciences - Medicine - Medical Clinics |
| Principal Investigator: | Marisa Passarelli |
| Grantee: | Marisa Passarelli |
| Host Institution: | Faculdade de Medicina (FM). Universidade de São Paulo (USP). São Paulo , SP, Brazil |
| City of the host institution: | São Paulo |
Abstract
Advanced glycation end products (AGE) are independently related to the development of atherosclerosis in diabetes mellitus (DM). By reducing the HDL half-life in plasma and the expression of ABCA-1 and ABCG-1 receptors and by increasing the expression of scavenger receptors and inflammatory markers, AGEs disturb the macrophage reverse cholesterol transport thus contributing to macrophage cholesterol accumulation. These events are related to the AGE-induced reactive oxygen species (ROS) generation, which can be prevented by anti-AGE compounds and chemical inhibitors of NADPH oxidase. In macrophages, the transcriptional activity of the ABCG-1 gene is down regulated by AGE-albumin; on the other hand, the reduced expression of ABCA-1 protein is not related to changes in gene transcription and mRNA levels. Thus, it is reasonable to postulate that post translational degradation, induced by redox imbalance and cell cholesterol accumulation, could contribute to the reduction in ABCA-1 expression elicited by AGE-albumin. Considering that albumin is the major circulating protein modified by glycation in DM and is used as a parameter of tight glycemic control, the objective of this study is to analyze in macrophages the role of in vivo and in vitro advanced glycated albumin in: 1) the differential expression of genes involved in lipid metabolism and inflammation; 2) ROS generation; 3) expression of endoplasmic reticulum stress markers and proteasomal degradation and 4) HDL-mediated lipid efflux. Macrophages will be treated with control albumin, isolated from healthy individual's serum or AGE-albumin, isolated from poorly controlled DM patients or modified in vitro by oxoaldehyde treatment. A detailed analysis of the effect of AGE in macrophage lipid metabolism and its relationship with inflammation and proteasomal degradation contribute to the comprehension of cell signaling involved in ABCA-1 regulation that ultimately brings on the development of atherosclerosis. (AU)
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