[U-133, a heat shock proteins inducer, precludes sleep disturbances in a model of the preclinical stage of Parkinson's disease in aged rats.]

Parkinson's disease (PD) is a chronic progressive neurodegenerative disease, closely associated with aging. It is considered incurable due to both late diagnosis and symptomatic treatment, which is able to alter neither molecular mechanisms of sleep disruption nor the neurodegenerative processes, developing with aging and PD progression. In the present study, we assess the therapeutic potential of a novel chaperone inducer U-133 (acetyl 2,3,7-tris-O-glucoside echinochrome) in the preclinical stage of PD modelled in aged rats by the inhibition of the proteasomal system in the brain. U-133 is a derivative of the sea urchin pigment echinochrome (2,3,5,7,8-pentahydroxy-1,4-naphthoquinone) produced by glycosylation, which possesses neuroprotective, antioxidant, anticancer properties. The administration of U-133, inducing the synthesis of Hsp70i and Hdj1 heat shock proteins in the brain, precludes the increase of light sleep (drowsiness) stage and the decrease of deep slow-wave sleep total time, both occurring with the progression of the preclinical stage of PD modelled in aged Wistar rats. Deep slow-wave sleep is thought to promote glymphatic clearance and to accelerate protein synthesis. Thus, U-133-induced increase in deep slow-wave sleep percentage, as compared to the preclinical model, is considered having a neuroprotective effect that contributes to the intensification of the restorative function of neurons and counteracts the progressing neurodegeneration.

Kinetics of chaperone activity of proteins Hsp70 and Hdj1 in human leukemia u-937 cells after preconditioning with thermal shock or compound u-133.

Kinetics of the chaperone activity of proteins Hsp70 and Hdj1 were analyzed in human U-937 promonocytes during their response to heat shock or to treatment with the echinochrome triacetyl glucoside derivative U-133. To measure the chaperone activity of both proteins, a special test was developed for their recognition and binding of a denatured protein. Using this test, the chaperone activity could be concurrently estimated in large numbers of cellular or tissue extracts. We also estimated the contents of both chaperones in cells by immunoblotting. The values for contents of Hsp70 and Hdj1 obtained by two independent test systems coincided, and this suggested that the substrate-binding activity could change proportionally to the chaperone content in the protein mixture. Therefore, the test developed by us can be employed for high throughput screening of drugs activating cellular chaperones. The analysis of quantity and activity of two cellular chaperones during the cell response to heat stress or to the drug-like substance U-133 showed that both factors caused the accumulation of chaperones with similar kinetics. We conclude that the efficiency of drug preconditioning could be close to the efficiency of hyperthermia and that the high activity of chaperones could be retained in human cells for no less than 1.5 days.

[Novel compounds increasing chaperone Hsp70 expression and their biological activity].

Hsp70 possesses chaperonic activity, the property associated with the protective function that was demonstrated in experiments on a great number of cell and animal models. Therefore, it seems important to search for the substances able to innocuously elevate the chaperone concentration in an organism cells and tissues. In our work, we screened of more that 60 compounds and found two chemicals, derivatives of shikonin and echinochrome that able to increase the chaperone level in a variety of human cells. It was shown that in human erythroleukemia K562 cells treated with the both substances concomitantly with elevation of Hsp70 level the absolute chaperonic activity was also increased; this can indicate mobilization of the whole cellular chaperonic machinery by above mentioned compounds. Estimating biological activity of the two substances, we demonstrated that treatments of cells by them prior to hard heat stress, hydrogen peroxide or staurosporine reduced cell mortality by 20-50 % depending on a cytotoxic factor. The results show that after simple chemical modifications these compounds might be taken as a basis of pharmaceuticals for therapy of wide range of disorders.