The Missing Link in the Human Thermoregulation Systems

Abstract

The study of human thermoregulation is one of the most developed areas of modern physiology and medicine. This is due to the important role of temperature in normal and pathological conditions. Directly or indirectly almost all systems and organs are involved in maintaining of relatively constant temperature in the body, since their normal functioning is closely related to the temperature of the internal environment (temperature homeostasis). Currently, the existence of two systems of thermoregulation is recognized: a physiological organ-based system with a center in the hypothalamus and a molecular system, which manifests itself in the form of the production of proteins (heat shock- and cold shock proteins) and by activation of RNA thermometers in response to heat or cold shock. Based on studies of the variability of chromosomal heterochromatin regions in the genome of human populations permanently living in various climatic and geographical conditions of Eurasia and Africa, as well as individuals well adapted to the extreme conditions of the high altitudes of the Pamirs and Tien-Shan (mountaineers) and the Far North (oil drillers of the Yamal Peninsula, Eastern Siberia), we came to the conclusion that, apparently, there is a third system of thermoregulation at the cellular level (cell thermoregulation). By cell thermoregulation, we mean the removal of excess heat from the nucleus of an interphase cell in order to avoid the harmful effects of high temperature on the complex molecular processes occurring in the nucleoplasm. We believe that some intracellular formations (a dense layer of condensed chromatin around the nucleus, nucleoli, chromocenters and other membraneless bodies) serve as a structural basis for the removal of heat from the cell nucleus, because the material basis of all these temporary structures in the interphase nucleus is the chromosomal heterochromatin regions. In this review, we discuss a set of data, which indicate that cell thermoregulation, may be a missing link between organism and molecular level in maintaining temperature homeostasis in the human body.