A method for bridging cell‐based transcriptomic and systematic data in obesity and aging studies (1180.2)

Abstract

We have reported the challenges of directly interpreting transcriptomic data at systems physiology levels, when hyper‐/hypotrophy or hyper‐/hypoplasia occurs (FASEB J 2007, 21:A1352). We found (1) some gene expressions were under whole body physiological controls; (2) some reflected compensatory feedback control or decompensation at organ levels. Transgenic manipulations on a gene or genes often follow the transcriptomic studies, but may lead to non‐physiological phenotypes and non‐pathophysiological interruption of the gene regulations and the cascade of signal transduction. Here we report a method to bridge the cellular transcriptomic data and tissue/systems physiology. In obesity studies with cell hypertrophy and hyperplasia and enlarged liver and adipose tissue masses, the collected tissues were weighted in whole and in small divided pieces before freezing immediately for DNA, protein and activity tests or after being socked in RANlater for gene expression test. The total DNA and RNA concentrations were measured as the indicators of cell number, assuming that total DNA is constant per cell at normal or disease conditions. Such middle information allowed us to convert the cellular transcriptomic data under the conditions with changes in cell size and number and tissue mass to a tissue/organ level and to interpret the outcomes under the regulations of systems physiology and pathology.