Distinct role of Hsp70 in Drosophila hemocytes during severe hypoxia

Abstract

Severe hypoxia can lead to injury and mortality in vertebrate or invertebrate organisms. Our research is focused on understanding the molecular mechanisms that lead to injury or adaptation to hypoxic stress using Drosophila as a model system. In this current study, we employed the UAS–Gal4 system to dissect the protective role of Hsp70 in specific tissues in vivo under severe hypoxia. In contrast to an over-expression in tissues like muscles, heart and brain, we found that over-expression of Hsp70 in hemocytes of flies provides a remarkable survival benefit to flies exposed to severe hypoxia for days. Furthermore, these flies were not only tolerant to severe hypoxia but also to other stresses such as oxidant stress (e.g., paraquat feeding or hyperoxia). Interestingly we observed that the better survival with Hsp70 over-expression in hemocytes under hypoxia or oxidant stress is causally linked to reactive oxygen species (ROS) reduction in whole flies. We also show that hemocytes are a major source of ROS generation, leading to injury during hypoxia and their elimination results in a better survival under hypoxia. Hence, our study identified a protective role of Hsp70 in Drosophila hemocytes which is linked to ROS reduction in the whole flies and thus helps in their remarkable survival during oxidant or hypoxic stress.

Selection of reference genes for qRT‐PCR and expression analysis of high‐altitude‐related genes in grassland caterpillars (Lepidoptera: Erebidae: Gynaephora) along an altitude gradient

“…Therefore, the HSP family may influence cold tolerance in TP Gynaephora species at various altitudes. Furthermore, the up‐regulated expression of HSPs has been detected in hypoxia‐induced and UV‐radiated insects, which is thought to be responsible for reducing reactive oxygen species (Azad, Ryu, & Haddad, 2011; King & MacRae, 2015). These studies indicate that ecological stressors represent a complex and diverse challenge for high‐altitude animals.…”

Insect Heat Shock Proteins During Stress and Diapause

“…melanogaster adults upregulate at least four HSP genes in the course of hypoxia, including Hsp23, Hsp67Bc, Hsp68, and Hsp40, with Hsp23 most responsive to oxygen deprivation (54). Overexpression of Hsp70 by the UAS-Gal4 system in Drosophila hemocytes and heart allows the insects to survive hypoxia for several days, an effect less evident with Hsp70 overexpression in muscle and brain, and these flies are resistant to insults such as oxidation (3). The enhanced protection is related to Hsp70 that reduces ROS in flies, an effect duplicated in an unknown way by hemocyte elimination (3).…”

Spirotetramat resistance adaption analysis of Aphis gossypii Glover by transcriptomic survey

“…The Hsp70 chaperones are essential proteins in all eukaryotes, and they participate in a large number of protein folding and unfolding processes that affect protein stability, activity, assembly, solubilization and localization [51][52][53]. Upregulation of Hsp70 genes has been reported in insects after exposure to pesticides [54,55], thermal stress [56,57] and oxidative stress [58,59]. Amino acid oxidization leads to the partial unfolding of proteins, and Hsp70s bind to the unfolded protein to stabilize the unfolded state, which allows progression of the unfolded protein along the folding pathway [60].…”