Heat stress modulated gastrointestinal barrier dysfunction: role of tight junctions and heat shock proteins

Abstract

Increased environmental temperature exerts a visible impact on an individual’s physiology. At the onset of heat stress, there is an increase in core body temperature which triggers peripheral vasodilation and sweating in an effort to dissipate the elevated body heat. The increase in peripheral circulation however reduces blood flow to the internal organs which are thus adversely affected. In particular, the gastrointestinal (GI) tract gets adversely affected during hyperthermia resulting in loosening of the tight junctions (TJs) that finally leads to higher intestinal permeability. At the cellular level, elevated levels of heat shock proteins (HSPs) induced in response to heat stress mediated cytoprotection by maintaining proper protein folding, releasing survival signals and preserving cytoskeleton integrity. Recent studies have indicated that HSPs play a crucial role in maintaining the localization of TJ proteins. Dietary supplements have also shown to have a positive effect on the maintenance of intestinal TJs. Therefore, it becomes imperative to understand the cellular, molecular and physiological alterations in response to heat stress in GI tract. In the present report, the effect of thermal stress on GI tract has been summarized. Specific role of HSPs along with mitogen activated protein (MAP) kinase signaling pathway in response to hyperthermia has also been discussed.

Keywords:

• Heat stress
• hyperthermia
• heat shock protein
• tight junction
• gastrointestinal tract and MAP kinase

Acknowledgements

We are thankful to Dr Bhuvnesh Kumar, Scientist ‘G’ & Director, DIPAS and Dr. Lilly Ganju, Scientist ‘G’ HOD, Molecular Biology, DIPAS for their support during the course of writing this review article.

Disclosure statement

There are no conflicts of interest.

Additional information

Funding

This work was supported by the Defence Institute of Physiology and Allied Sciences (DIPAS), Defence Research and Development Organization (DRDO) under Project No. DIPAS/TASK-184, Ministry of Defence, Government of India. AG, NRC and DC are supported by a fellowship from the DRDO and AS is supported by a fellowship from the Council of Scientific and Industrial Research, Government of India.