Bridging cell‐based gene expression and system biology research: what is required when tissue hypotrophy and hypoplasia occur?

Abstract

Although gene expression studies unmask useful mechanism information at cellular levels, it may encounter some correlation difficulties or paradoxes in explaining anti-adiposity at system biology settings. Receptors and signal transduction mediators are solely regulated to meet intracellular physiological requirements. Our studies showed dramatic weight loss and a 38% volume reduction of abdominal fat pad with herbal WL2 (FASEB J 2006, 20:A587). Array analysis on several organs revealed up-regulated gene expressions of GHR, adrenergic R, thyroid R, adiponectin R, GLUT-2 in muscle and liver and apoptotic genes in adipocytes (p<0.05), and more, suggesting changes in multiple metabolic pathways with WL2 (companion abstract #1279). While biosynthesis, intracellular transportation and secretion of circulating hormones and cytokines are regulated in response to the physiological demands of whole body, with or without changes in the adipocyte mass. Expression of adiponectin gene was found unchanged per cell (−1.1%, p=0.27), paradoxical to the reduction of circulating adiponectin (−27%, p=0.005). When normalizing the data with cell number (DNA) and tissue weight, we found that the expression of adiponectin gene was actually reduced in a whole body level (−26%, p=0.009). Although several biological processes are in between gene transcription and appearance of adiponectin in blood, such normalizations opened an avenue to virtually bridge the data obtained from cell and system biology studies.