Premium
Using Dynamic Gene Module Map Analysis To Identify Targets That Modulate Free Fatty Acid Induced Cytotoxicity
Author(s) -
Li Zheng,
Srivastava Shireesh,
Findlan Robert,
Chan Christina
Publication year - 2008
Publication title -
biotechnology progress
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.572
H-Index - 129
eISSN - 1520-6033
pISSN - 8756-7938
DOI - 10.1021/bp070120b
Subject(s) - pentose phosphate pathway , metabolic pathway , cytotoxicity , biological pathway , biochemistry , ketone bodies , fatty acid , biology , citric acid cycle , chemistry , saturated fatty acid , fatty acid synthesis , gene , lipotoxicity , metabolism , glycolysis , gene expression , in vitro , insulin resistance , insulin , endocrinology
The objective of this study was to identify pathways that regulate the cytotoxicity induced by free fatty acids (FFAs) in human hepatoblastoma cells (HepG2/C3A). Gene expression profiles of HepG2/C3A cells were obtained at three time points, after 24, 48, and 72 h of exposure to different types of FFA. Saturated fatty acid (palmitate) was found to be cytotoxic. The pathways activated by the different FFAs at the different time points were identified using global gene module map analysis. Unsaturated FFAs exerted transcriptional regulation mainly within the first 24 h, whereas saturated FFA, palmitate, regulated energy production pathways, such as the electron transport chain (ETC) and tricarboxylic acid cycle, within the first 24 h. In the next 24 h, palmitate up‐regulated 36 cell death relevant pathways and down‐regulated several protective pathways, such as the pentose phosphate pathway and glutathione‐related pathways. In the final 24 h, the FFAs did not induce significant transcriptional regulation. We hypothesized that palmitate induced cytotoxicity by first perturbing metabolic pathways in the initial 24 h, resulting in changes to factors, such as metabolites or signaling molecules, which subsequently triggered cell death relevant pathways in the next 24 h. The uptake and release of 27 metabolites were measured to further elucidate the metabolic changes in the first 24 h. It was determined that ketone bodies such as β‐hydroxybutyrate and acetoacetate were important in separating the toxic from the nontoxic phenotypes. A regression model was used to identify the genes relevant to these metabolites. Some of the genes identified to be important were experimentally validated. It was found that ETC genes such as NADH dehydrogenase and succinate dehydrogenase were involved in palmitate induced cytotoxicity.