Characterization and regulation of cold-induced heat shock protein
expression in mouse brown adipose tissue.
Matz, Jeannine M., Michael J. Blake, Hal M. Tatelman, Kathleen P.
Lavoi, and Nikki J. Holbrook.
Department of Pharmacology and Toxicology, University of North
Dakota, Grand Forks, ND 58202 & Section on Gene Expression and Aging,
National Institute on Aging, Gerontology Research Center, Baltimore,
MD 21224
APStracts 2:0025R, 1995.
The accumulation of Heat Shock Proteins (HSPs) following the exposure
of cells or organisms to elevated temperatures is well established.
It is also known that a variety of other environmental and cellular
metabolic stressors can induce HSP synthesis. However, few studies
have investigated the effect of cold temperature on HSP expression.
Here we report that exposure of ICR mice to cold ambient temperatures
results in a tissue-selective induction of HSPs in brown adipose
tissue (BAT) coincident with the induction of mitochondrial
uncoupling protein (UCP) synthesis. Cold-induced HSP expression is
associated with enhanced binding of heat shock transcription factors
to DNA, similar to that which occurs following exposure of cells or
tissues to heat and other metabolic stresses. Adrenergic receptor
antagonists were found to block cold-induced HSP70 expression in BAT
while adrenergic agonists induced BAT HSP expression in the absence
of cold exposure. These findings suggest that norepinephrine,
released in response to cold exposure, induces HSP expression in BAT.
Norepinephrine appears to initiate transcription of HSP genes after
binding to BAT adrenergic receptors through, as yet, undetermined
signal transduction pathways. Thermogenesis results from an increase
in activity and synthesis of several metabolic enzymes in BAT of
animals exposed to cold challenge. The concomitant increase in HSPs
may function to facilitate the translocation and activity of the
enzymes involved in this process.
Received 17 August 1994; accepted in final form 22 January 1995.
APS Manuscript Number R456-4.
Article publication pending Am. J. Physiol. (Regulatory Integrative
Comp. Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 25 February 1995.