Insights into the role of heat shock protein 72 to whole-body heat acclimation in humans

Heat acclimation (HA) results in whole body adaptations that increase heat tolerance, and in addition, HA may also result in protective cellular adaptations. We hypothesized that, after HA, basal intracellular heat shock protein (HSP) 72 and extracellular IL-10 levels would increase, while extracellular HSP72 levels decrease. Ten male and two female subjects completed a 10-day exercise/HA protocol (100-min exercise bout at 56% of maximum O2 uptake in a 42.5°C DB, 27.9% RH environment); subjects exhibited classic adaptations that accompany HA. Peripheral blood mononuclear cells (PBMCs) were isolated before and after each acclimation session on days 1, 6, and 10; plasma and serum were collected before and after exercise on the 1st and 10th day of HA. SDS-PAGE was used to determine PBMC HSP72 levels during HA, and ELISA was used to measure plasma IL-10 and serum HSP72 concentrations. The increase in PBMC HSP72 from pre- to postexercise on the 1st day of HA was not significant (mean ± SD, 1.0 ± 0 vs. 1.6 ± 0.6 density units). Preexercise HSP72 levels on day 1 were significantly lower compared with the pre- and postexercise samples on days 6 and 10 (mean ± SD, day 6: 2.1 ± 1.0 and 2.2 ± 1.0, day 10: 2.0 ± 1.3 and 2.2 ± 1.0 density units, respectively, P < 0.05). There were no differences in plasma IL-10 and serum HSP72 postexercise or after 10 days of HA. The sustained elevation of HSP72 from days 6 to 10 may be evidence of a cellular adaptation to HA that contributes to improved heat tolerance and reduced heat illness risk.

Download Full-text

Human physiological and heat shock protein 72 adaptations during the initial phase of humid-heat acclimation

Journal of Thermal Biology ◽

10.1016/j.jtherbio.2007.04.003 ◽

2007 ◽

Vol 32 (6) ◽

pp. 341-348 ◽

Cited By ~ 24

Author(s):

Helen C. Marshall ◽

Samantha A. Campbell ◽

Craig W. Roberts ◽

Myra A. Nimmo

Keyword(s):

Heat Shock ◽

Heat Shock Protein ◽

Initial Phase ◽

Heat Acclimation ◽

Heat Shock Protein 72

Download Full-text

A Novel Mechanism for Cross-Adaptation between Heat and Altitude Acclimation: The Role of Heat Shock Protein 90

Physiology Journal ◽

10.1155/2014/121402 ◽

2014 ◽

Vol 2014 ◽

pp. 1-12 ◽

Cited By ~ 6

Author(s):

Roy M. Salgado ◽

Ailish C. White ◽

Suzanne M. Schneider ◽

Christine M. Mermier

Keyword(s):

Heat Stress ◽

Heat Shock ◽

Heat Shock Protein ◽

Heat Shock Protein 90 ◽

Heat Acclimation ◽

Functional Roles ◽

Hypoxic Environment ◽

Client Proteins

Heat shock protein 90 (HSP90) is a member of a family of molecular chaperone proteins which can be upregulated by various stressors including heat stress leading to increases in HSP90 protein expression. Its primary functions include (1) renaturing and denaturing of damaged proteins caused by heat stress and (2) interacting with client proteins to induce cell signaling for gene expression. The latter function is of interest because, in cancer cells, HSP90 has been reported to interact with the transcription hypoxic-inducible factor 1α (HIF1α). In a normoxic environment, HIF1α is degraded and therefore has limited physiological function. In contrast, in a hypoxic environment, stabilized HIF1α acts to promote erythropoiesis and angiogenesis. Since HSP90 interacts with HIF1α, and HSP90 can be upregulated from heat acclimation in humans, we present a proposal that heat acclimation can mimic molecular adaptations to those of altitude exposure. Specifically, we propose that heat acclimation increases HSP90 which then stabilizes HIF1α in a normoxic environment. This has many implications since HIF1α regulates red blood cell and vasculature formation. In this paper we will discuss (1) the functional roles of HSP90 and HIF1α, (2) the interaction between HSP90 and other client proteins including HIF1α, and (3) results from in vitro studies that may suggest how the relationship between HSP90 and HIF1α might be applied to individuals preparing to make altitude sojourns.

Download Full-text