Heat Shock Protein Hsp70 Expression Research Articles

Magnetic and GRPR-targeted reduced graphene oxide/doxorubicin nanocomposite for dual-targeted chemo-photothermal cancer therapy

Herein, we design a rGO-based magnetic nanocomposite by decorating rGO with citrate-coated magnetic nanoparticles (CMNP). The magnetic rGO (mrGO) was modified by phospholipid-polyethylene glycol to prepare PEGylated mrGO, for conjugating with gastrin-releasing peptide receptor (GRPR)-binding peptide (mrGOG). The anticancer drug doxorubicin (DOX) was bound to mrGO (mrGOG) by π-π stacking for drug delivery triggered by the low pH value in the endosome. The mrGOG showed enhanced photothermal effect under NIR irradiation, endorsing its role for dual targeted DOX delivery. With efficient DOX release in the endosomal environment and heat generation from light absorption in the NIR range, mrGOG/DOX could be used for combination chemo-photothermal therapy after intracellular uptake by cancer cells. We characterized the physico-chemical as well as biological properties of the synthesized nanocomposites. The mrGOG is stable in biological buffer solution, showing high biocompatibility and minimum hemolytic properties. Using U87 glioblastoma cells, we confirmed the magnetic drug targeting effect in vitro for selective cancer cell killing. The peptide ligand-mediated targeted delivery increases the efficiency of intracellular uptake of both nanocomposite and DOX up to ~3 times due to the over-expressed GRPR on U87 surface, leading to higher cytotoxicity. The increased cytotoxicity using mrGOG over mrGO was shown from a decreased IC50 value (0.70 to 0.48 μg/mL) and an increased cell apoptosis rate (19.8% to 47.1%). The IC50 and apoptosis rate changed further to 0.19 μg/mL and 76.8% in combination with NIR laser irradiation, with the photothermal effect supported from upregulation of heat shock protein HSP70 expression. Using U87 tumor xenograft model created in nude mice, we demonstrated that magnetic guidance after intravenous delivery of mrGOG/DOX could significantly reduce tumor size and prolong animal survival over free DOX and non-magnetic guided groups. Augmented with NIR laser treatment for 5 min, the anti-cancer efficacy significantly improves with elevated cell apoptosis and reduced cell proliferation. Together with safety profiles from hematological as well as major organ histological analysis of treated animals, the mrGOG nanocomposite is an effective nanomaterial for combination chemo-photothermal cancer therapy.

The Effect of a Single Heating Treatment on Laboratory Mice Behavior, Adult Neurogenesis, and the Expression of Heatshock Protein HSP-70

Male hybrid mice (F1 CBA × C57BL/6J) were kept for 1.5 h at 39.5°С. In cognitive tests (extrapolation and puzzle-box elementary logic task solution), mice of the experimental groups (after exposure to an elevated temperature) solved the tasks more quickly and more successfully, while their activity in the “small open field” (in which no stress-inducing stimuli were present) and in the Porsolt test (unescapable swimming) was higher than in control mice. In separate experiments, the temporary impairment in the adult neurogenesis (the decrease of new cell numbers detected immunо-histochemically by the marker Ki67) after elevated temperature exposure was demonstrated in both the subgranular area of dentate fascia and in the subventricular proliferative zone of the forebrain. The heating treatment was accompanied by the increase of HSP-70 expression at the time point 3 h after the treatment, while no differences from control were found after 24 h.

Down regulation of Hsp70 expression level prolongs the duration of heat‐induced male sterility in Drosophila buzzatii

Summary The relationship between heat shock protein Hsp70 expression level and the duration of heat‐induced male sterility was investigated in four populations of Drosophila buzzatii Patterson and Wheeler. The effect of heat hardening on the duration of sterility was further examined after flies developed at either 25 or 31 °C. In addition, Hsp70 expression was measured in testes after development at three different thermal regimes. Four main hypotheses were tested: (i) Hsp70 is expressed in testes of D. buzzatii males even at non‐stressful temperatures, and the level of expression increases with increasing rearing temperature. (ii) Hsp70 expression level differs between populations and is negatively correlated with the duration of poststress sterility. (iii) Experimentally induced Hsp70 expression at the pupal stage shortens the sterility period of flies reared above the temperature threshold of sterility. (iv) In contrast, a hardening treatment during the pupal stage of flies reared at 25 °C results in a longer time to fertility. The results matched the hypotheses, leading to the conclusion that higher Hsp70 expression reduces the duration of heat‐induced male sterility.

Heat shock protein Hsp70 expression and DNA damage in Baikalian sponges exposed to model pollutants and wastewater from Baikalsk Pulp and Paper Plant

Lake Baikal, a unique habitat for a great number of endemic species, is the largest freshwater reservoir in the world which is still largely unaffected by anthropogenic pollution, except for some shore regions with industrial activity. The expressions of a biomarker of exposure (heat shock protein Hsp70) and a biomarker of effect (DNA single-strand breaks) were measured for the first time in endemic Baikalian sponge species ( Baikalospongia intermedia, Lubomirskia fusifera, and Lubomirskia abietina). Tissue cubes of B. intermedia and dissociated cells of L. fusifera and L. abietina reacted to temperature stress (10–16 °C above ambient temperature) with a time-dependent increase in expression of Hsp70. In B. intermedia, the effects of model pollutants (lead, copper, and zinc, and the organochlorines tetrachloroguaiacol, TCG, and pentachlorophenol, PCP) and of the wastewater from the final refinement and aeration reservoirs of the Baikalsk Pulp and Paper Plant (BPPP), located at the shore of the southern basin of Lake Baikal, on the expression of Hsp70 and the extent of DNA damage were investigated. It was found that lead and zinc but not copper cause a strong induction of Hsp70 in this sponge, while the frequency of DNA single-strand breaks increased after exposure to all these heavy metals tested. Induction of DNA single-strand breaks was also observed after exposure to TCG and PCP, but these compounds did not (consistently) enhance Hsp70 expression. Wastewater taken from the final water aeration pond of BPPP caused a concentration-dependent increase in Hsp70 expression in B. intermedia. However, there was no difference in the basal levels of Hsp70 between sponges collected in the shallow water at an unpolluted site near Baikalsk City and at a polluted site where the wastewaters of BPPP are discharged into the lake. There was also no clear difference in the wastewater concentration-dependent induction of Hsp70 expression between sponges collected at these sites, indicating no adaptation to continuous stress exposure.