Stress causes decrease in vascular relaxation linked with altered phosphorylation of heat shock proteins

Leslie C. Fuchs, Ararat D. Giulumian, Louis Knoepp, Walter Pipkin, Mary Dickinson, Chad Hayles, Colleen Brophy
2000 American Journal of Physiology. Regulatory Integrative and Comparative Physiology  
Stress causes decrease in vascular relaxation linked with altered phosphorylation of heat shock proteins. Am J Physiol Regulatory Integrative Comp Physiol 279: R492-R498, 2000.-Cyclic nucleotide-dependent vascular relaxation is associated with increases in the phosphorylation of a small heat shock protein (HSP), HSP20. An increase in phosphorylation of another small HSP, HSP27, is associated with impaired cyclic nucleotide-dependent vascular relaxation. Expression of HSPs is altered by exposure
more » ... altered by exposure to several types of cellular stress in vitro. To determine if behavioral stress in vivo alters vascular expression and phosphorylation of the small HSPs and cyclic nucleotide-dependent vascular relaxation, borderline hypertensive rats were stressed by restraint and exposure to air-jet stress 2 h/day for 10 days or remained in their home cage. Stress impaired relaxation of aorta to forskolin, which activates adenylyl cyclase, and sodium nitroprusside, which activates guanylyl cyclase. This was associated with an increase in the aortic expression and phosphorylation of HSP27, which was localized to the vascular smooth muscle, but a decrease in the amount of phosphorylated (P)-HSP20. To determine if P-HSP27 inhibits phosphorylation of HSP20, P-HSP27 was added to a reaction mixture containing recombinant HSP20 and the catalytic subunit of cAMP-dependent protein kinase. P-HSP27 inhibited phosphorylation of HSP20 in a concentration-dependent manner. These data demonstrate that P-HSP27 can inhibit phosphorylation of HSP20. The increase in P-HSP27 and decrease in P-HSP20 were associated with reduced cyclic nucleotide-dependent vascular smooth muscle relaxation in response to behavioral stress in vivo, an effect similar to that observed previously in response to cellular stress in vitro. behavioral stress; vascular smooth muscle; hypertension EXPOSURE OF ORGANISMS TO STRESS leads to activation of the hypothalamic-pituitary-adrenal axis with the production and release of catecholamines. On a cellular level, stress is associated with the induction of a group of proteins termed heat shock proteins (HSPs). The heat shock response was first described in Drosophila
doi:10.1152/ajpregu.2000.279.2.r492 pmid:10938237 fatcat:tjvqnyzpkbfobaig4jbbirsm4e