Expression of adipocyte biomarkers in a primary cell culture model reflects pre-weaning adipobiology [Developmental Biology]

May 7th, 2014 by Chu, D.-T., Malinowska, E., Gawronska-Kozak, B., Kozak, L. P.

A cohort of genes was selected to characterize the adipogenic phenotype in primary cell cultures from 3 tissue sources. We compared the quantitative expression of a biomarker in culture relative to the expression in vivo, since the mere presence or absence of expression is minimally informative. Although all biomarkers analyzed have biochemical functions in adipocytes, the expression of some of the biomarkers varied enormously in culture relative to their expression in the adult fat tissues in vivo, i.e. inguinal fat (ING) for white adipocytes and brite cells, interscapular brown adipose tissue (iBAT) for brown adipocytes and ear mesenchymal stem cells for white adipocytes from adult mice. We propose that the pattern of expression in vitro does not reflect gene expression in an adult mouse, rather it is predominantly the pattern of adipose tissue of the developing mouse between birth and weaning. The variation in gene expression among fat depots in both human and rodent has been an extensively studied phenomenon and as recently reviewed, it is related to sub-phentoypes associated with the immune function, the inflammatory response, fat depot blood flow and insulin sensitivity (1). We suggest that adipose tissue biology in the period from birth to weaning is not just a staging platform for the emergence of adult white fat, but that it has properties to serve the unique needs of energy metabolism in the newborn. A case in point is the differentiation of brite cells which occurs during this period, followed by their involution immediately following weaning (2).