Harry J. Mersmann, PhD
No longer at Baylor College of Medicine
Research Chemist, Agricultural Research Service
Regulation of Adipocyte Differentiation
My research concerns the bioregulation of the differentiation and
growth of adipocytes. Precursor cells (preadipocytes) when confronted
with the appropriate milieu of hormones and growth factors begin
to differentiate. One of the early events in differentiation is
an increase in the transcription and translation of specific transcription
factors, particularly those of the CCAAT enhancer binding protein
(C/EBP) and the peroxisome proliferator-activated receptor (PPAR)
families. Genes for a number of proteins that define the adipocyte
phenotype have response elements for PPAR and C/EBP. In this manner,
these transcription factors control the transcription and translation
of these proteins and thus, the differentiation of adipocytes.
Previous efforts of this laboratory were to study the ß-adrenergic
receptor (ßAR) modulation of adipocyte hypertrophy via regulation
of adipocyte lipid metabolism. Major species differences were observed
in the ßAR subtypes present in adipocytes and thus in the
pharmacological regulation of adipocyte growth. Current efforts
are to understand nutrient gene interaction in the regulation of
adipocyte differentiation and growth. Of particular interest has
been the role of individual long-chain fatty acids in the regulation
of differentiation. Some fatty acids stimulate, some have little
or no effect, and some inhibit differentiation of porcine preadipocytes
in vitro. The mechanism for fatty acid stimulation of differentiation
may reside in their acting as ligands for PPARg.
McNeel, R.L. and H.J. Mersmann . 2003.
Effects of isomers of conjugated linoleic acid on porcine
adipocyte growth and differentiation. J. Nutr. Biochem.
Ding, S-T., R.L. McNeel, and H.J. Mersmann
. 2002. Modulation of adipocyte determination and differentiation-dependent
factor 1 by selected polyunsaturated fatty acids. In
Vitro Cell. Dev. Biol. - Animal. 38:352-357.
Mersmann, H.J. 2002. Mechanisms for conjugated linoleic
acid-mediated reduction in fat deposition. J. Anim.
Sci. 80(E. Suppl. 2):E126-E134.
Ding, S-T. and H.J. Mersmann. 2001. Fatty acids
modulate porcine adipocyte differentiation and transcripts
for transcription factors and adipocyte-characteristic
proteins. J. Nutr. Biochem. 12:101-108.
McNeel, R.L., S-T. Ding, E.O = Brian Smith, and
H.J. Mersmann. 2000. Expression of porcine adipocyte
transcripts during differentiation in vitro and in
vivo. Comp. Biochem. Physiol. (Part B) 126:291-302.
McNeel, R.L. and H.J. Mersmann. 2000. Nutritional
deprivation reduces the transcripts for transcription
factors and adipocyte-characteristic proteins in porcine
adipocytes. J. Nutr. Biochem. 11:139-146.
McNeel, R.L. and H.J. Mersmann. 1999. Distribution
and quantification of beta1-, beta2-, and beta3-adrenergic
receptor subtype transcripts in porcine tissues. J.
Anim. Sci. 77:611-621.