Chaperone Hsp70 (HSPA1) Is Involved in the Molecular Mechanisms of Sleep Cycle Integration

The molecular mechanisms of sleep cycle integration at the beginning and the end of the inactive period are not clear. Sleep cycles with a predominance of deep slow-wave sleep (SWS) seem to be associated with accelerated protein synthesis in the brain. The inducible Hsp70 chaperone corrects protein conformational changes and has protective properties. This research explores (1) whether the Hspa1 gene encoding Hsp70 protein activates during the daily rapid-eye-movement sleep (REMS) maximum, and (2) whether a lower daily deep SWS maximum affects the Hspa1 expression level during the subsequent REMS. Combining polysomnography in male Wistar rats, RT-qPCR, and Western blotting, we reveal a three-fold Hspa1 upregulation in the nucleus reticularis pontis oralis, which regulates REMS. Hspa1 expression increases during the daily REMS maximum, 5–7 h after the natural peak of deep SWS. Using short-term selective REMS deprivation, we demonstrate that REMS rebound after deprivation exceeds the natural daily maximum, but it is not accompanied by Hspa1 upregulation. The results suggest that a high proportion of deep SWS, usually observed after sleep onset, is a necessary condition for Hspa1 upregulation during subsequent REMS. The data obtained can inform the understanding of the molecular mechanisms integrating SWS and REMS and key biological function(s) of sleep.

Heat Shock Protein HSP70 in Oxidative Stress in Apnea Patients

We studied the level of heat shock protein HSP70 under conditions of oxidative stress in 47 patients with apnea. The control group included 13 healthy subjects without verified apnea. Blood serum, plasma, and erythrocyte hemolysate were used to determine LPO and anti-oxidant protection components by spectrophotometrical and spectrofluorometrical methods. HSP70 was assayed by ELISA. A direct relationship was established between the intensity of oxidative stress and HSP70 expression in patients with apnea. Quantitative determination of HSP70 can be used as a molecular marker in the early diagnosis and prognosis of the development of various pathological conditions in hypoxia.