[Regulation of heat shock gene expression in response to stress]

Phylogenetic annotation of Caenorhabditis elegans heat shock protein 70 genes

Annotation of the 70 kDa heat shock proteins (Hsp70s) has been chaotic especially in invertebrates. In this study, we validated an emerging nomenclature of Hsp70s, which can be potentially applied to all metazoan Hsp70s, by conducting a genome-wide annotation of Caenorhabditis elegans Hsp70s. Using the phylogenetic annotation, the seven canonical C. elegans Hsp70s were successfully classified into four known lineages, cytosolic A, cytosolic B, endoplasmic reticulum, and mitochondria. Motifs specific to each lineage were all conserved in the C. elegans Hsp70s. From these results, we propose new aliases of C. elegans Hsp70s that should help future annotation of this important molecular chaperone.

Inflammation: A New Look at an Old Problem

Pro-inflammatory stress is inherent in any cells that are subject to damage or threat of damage. It is defined by a number of universal components, including oxidative stress, cellular response to DNA damage, unfolded protein response to mitochondrial and endoplasmic reticulum stress, changes in autophagy, inflammasome formation, non-coding RNA response, formation of an inducible network of signaling pathways, and epigenetic changes. The presence of an inducible receptor and secretory phenotype in many cells is the cause of tissue pro-inflammatory stress. The key phenomenon determining the occurrence of a classical inflammatory focus is the microvascular inflammatory response (exudation, leukocyte migration to the alteration zone). This same reaction at the systemic level leads to the development of life-critical systemic inflammation. From this standpoint, we can characterize the common mechanisms of pathologies that differ in their clinical appearance. The division of inflammation into alternative variants has deep evolutionary roots. Evolutionary aspects of inflammation are also described in the review. The aim of the review is to provide theoretical arguments for the need for an up-to-date theory of the relationship between key human pathological processes based on the integrative role of the molecular mechanisms of cellular and tissue pro-inflammatory stress.

Phylogenetic annotation of Drosophila melanogaster heat shock protein 70 genes

The traditional classification of stress-inducible 70 kDa heat shock protein (Hsp70) and heat shock cognate (Hsc70) requires a revision because of a recent finding that neither of them constitutes a monophyletic gene family. Here we inferred a phylogenetic relationship among Drosophila melanogaster Hsp70 family members. D. melanogaster Hsp70 family members were separated into four known metazoan Hsp70 lineages: cytosolic A, cytosolic B, endoplasmic reticulum, and mitochondria. Hsc70s sporadically distributed in the phylogenetic tree, indicating their paraphyletic origin. Detailed sequence inspection found several motifs that support the phylogenetic analysis. Taken together, we propose new aliases of D. melanogaster Hsp70 family members based on their evolutionary history.

PLOD1 acts as a tumor promoter in glioma via activation of the HSF1 signaling pathway

Procollagen-lysine, 2-oxoglutarate 5-dioxygenase 1 (PLOD1) is a collagen-related lysyl hydroxylase and its prognostic value in glioma patients was verified. However, its biological function in glioma has yet to be fully investigated. The PLOD1 mRNA status and clinical significance in gliomas were assessed via the GEPIA database. Overexpression or targeted depletion of PLOD1 was carried out in the human glioma cell line U87 and verified by western blotting. CCK8 and colony formation assays were implemented to examine the impact of PLOD1 on the proliferative and colony-forming phenotypes of U87 cells. Luciferase reporter assays and HSF1-specific pharmacologic inhibitors (KRIBB11) were employed to determine the regulatory relationship between PLOD1 and heat shock factor 1 (HSF1). High expression of PLOD1 was observed in tissue samples of glioblastoma multiforme (GBM) and brain lower-grade glioma (LGG). GEPIA overall survival further demonstrated that both GBM and LGG patients with high PLOD1 displayed worse clinical outcomes compared with those with low PLOD1. Overexpression and targeted depletion of PLOD1 enhanced and suppressed U87 cell proliferation and colony formation, respectively. Luciferase reporter assays showed that PLOD1 significantly enhanced the transcriptional activity of HSF1 in HEK293T cells. PLOD1 deficiency in U87 cells inhibited HSF1-induced survivin accumulation, whereas KRIBB11 also blocked the PLOD1-overexpressing induced survivin expression. An inhibitor of HSF1 signaling events abolished the increased clonogenic potential caused by PLOD1 overexpression in U87 cells. High expression of PLOD1 can increase the proliferation and colony formation of U87 cells by activating the HSF1 signaling pathway. This study suggested PLOD1/HSF1 as an effective therapeutic target for gliomas.

Functional implication of heat shock protein 70/90 and tubulin in cold stress of Dermacentor silvarum

Background

The tick Dermacentor silvarum Olenev (Acari: Ixodidae) is a vital vector tick species mainly distributed in the north of China and overwinters in the unfed adult stage. The knowledge of the mechanism that underlies its molecular adaptation against cold is limited. In the present study, genes of hsp70 and hsp90 cDNA, named Dshsp70 and Dshsp90, and tubulin were cloned and characterized from D. silvarum, and their functions in cold stress were further evaluated.

Methods

The genome of the heat shock proteins and tubulin of D. silvarum were sequenced and analyzed using bioinformatics methods. Each group of 20 ticks were injected in triplicate with Dshsp90-, Dshsp70-, and tubulin-derived dsRNA, whereas the control group was injected with GFP dsRNA. Then, the total RNA was extracted and cDNA was synthesized and subjected to RT-qPCR. After the confirmation of knockdown, the ticks were incubated for 24 h and were exposed to − 20 °C lethal temperature (LT50), and then the mortality was calculated.

Results

Results indicated that Dshsp70 and Dshsp90 contained an open reading frame of 345 and 2190 nucleotides that encoded 114 and 729 amino acid residues, respectively. The transcript Dshsp70 showed 90% similarity with that identified from Dermacentor variabilis, whereas Dshsp90 showed 85% similarity with that identified from Ixodes scapularis. Multiple sequence alignment indicates that the deduced amino acid sequences of D. silvarum Hsp90, Hsp70, and tubulin show very high sequence identity to their corresponding sequences in other species. Hsp90 and Hsp70 display highly conserved and signature amino acid sequences with well-conserved MEEVD motif at the C-terminal in Hsp90 and a variable C-terminal region with a V/IEEVD-motif in Hsp70 that bind to numerous co-chaperones. RNA interference revealed that the mortality of D. silvarum was significantly increased after injection of dsRNA of Dshsp70 (P = 0.0298) and tubulin (P = 0.0448), whereas no significant increases were observed after the interference of Dshsp90 (P = 0.0709).

Conclusions

The above results suggested that Dshsp70 and tubulin play an essential role in the low-temperature adaptation of ticks. The results of this study can contribute to the understanding of the survival and acclimatization of overwintering ticks.

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s13071-021-05056-y.

The complex evolution of the metazoan HSP70 gene family

The metazoan 70-kDa heat shock protein (HSP70) family contains several members localized in different subcellular compartments. The cytosolic members have been classified into inducible HSP70s and constitutive heat shock cognates (HSC70s), but their distinction and evolutionary relationship remain unclear because of occasional reports of “constitutive HSP70s” and the lack of cross-phylum comparisons. Here we provide novel insights into the evolution of these important molecular chaperones. Phylogenetic analyses of 125 full-length HSP70s from a broad range of phyla revealed an ancient duplication that gave rise to two lineages from which all metazoan cytosolic HSP70s descend. One lineage (A) contains a relatively small number of genes from many invertebrate phyla, none of which have been shown to be constitutively expressed (i.e., either inducible or unknown). The other lineage (B) included both inducible and constitutive genes from diverse phyla. Species-specific duplications are present in both lineages, and Lineage B contains well-supported phylum-specific clades for Platyhelminthes, Rotifera, Nematoda, Porifera/Cnidaria, and Chordata. Some genes in Lineage B have likely independently acquired inducibility, which may explain the sporadic distribution of “HSP70” or “HSC70” in previous phylogenetic analyses. Consistent with the diversification history within each group, inducible members show lower purifying selection pressure compared to constitutive members. These results illustrate the evolutionary history of the HSP70 family, encouraging us to propose a new nomenclature: “HSP70 + subcellular localization + linage + copy number in the organism + inducible or constitutive, if known.” e.g., HSP70cA1i for cytosolic Lineage A, copy 1, inducible.

Role of a Heat Shock Transcription Factor and the Major Heat Shock Protein Hsp70 in Memory Formation and Neuroprotection

Heat shock proteins (Hsps) represent the most evolutionarily ancient, conserved, and universal system for protecting cells and the whole body from various types of stress. Among Hsps, the group of proteins with a molecular weight of 70 kDa (Hsp70) plays a particularly important role. These proteins are molecular chaperones that restore the native conformation of partially denatured proteins after exposure to proteotoxic forms of stress and are critical for the folding and intracellular trafficking of de novo synthesized proteins under normal conditions. Hsp70s are expressed at high levels in the central nervous system (CNS) of various animals and protect neurons from various types of stress, including heat shock, hypoxia, and toxins. Numerous molecular and behavioral studies have indicated that Hsp70s expressed in the CNS are important for memory formation. These proteins contribute to the folding and transport of synaptic proteins, modulate signaling cascades associated with synaptic activation, and participate in mechanisms of neurotransmitter release. In addition, HSF1, a transcription factor that is activated under stress conditions and mediates Hsps transcription, is also involved in the transcription of genes encoding many synaptic proteins, whose levels are increased in neurons under stress and during memory formation. Thus, stress activates the molecular mechanisms of memory formation, thereby allowing animals to better remember and later avoid potentially dangerous stimuli. Finally, Hsp70 has significant protective potential in neurodegenerative diseases. Increasing the level of endogenous Hsp70 synthesis or injecting exogenous Hsp70 reduces neurodegeneration, stimulates neurogenesis, and restores memory in animal models of ischemia and Alzheimer’s disease. These findings allow us to consider recombinant Hsp70 and/or Hsp70 pharmacological inducers as potential drugs for use in the treatment of ischemic injury and neurodegenerative disorders.

Zinc alleviates the heat stress of primary cultured hepatocytes of broiler embryos via enhancing the antioxidant ability and attenuating the heat shock responses

Zinc (Zn) has been shown to attenuate the adverse effects of heat stress on broilers, but the mechanisms involving this process remain unclear. We aimed to investigate possible protective mechanisms of Zn on primary cultured hepatocytes of broiler embryos subjected to heat stress. Three experiments were conducted. In Exp. 1, hepatocytes were treated with 0, 50, 100, 200, or 400 μmol/L added Zn as inorganic Zn sulfate (iZn) for 12, 24 or 48 h. In Exp. 2, cells were exposed to 40 °C (a normal temperature [NT]) and 44 °C (a high temperature [HT]) for 1, 2, 4, 6, or 8 h. In Exp. 3, cells were preincubated with 0 or 50 μmol/L Zn as iZn or organic Zn lysine chelate (oZn) for 8 h under NT, and then incubated with the same Zn treatments under NT or HT for 4 or 6 h. The biomarkers of antioxidative status and heat stress in cells were measured. The results in Exp. 1 indicated that 50 μmol/L Zn and 12 h incubation were the optimal conditions for increasing antioxidant ability of hepatocytes. In Exp. 2, the 4 or 6 h incubation under HT was effective in inducing heat shock responses of hepatocytes. In Exp. 3, HT elevated (P < 0.01) malondialdehyde content and expressions of heat shock protein 70 (HSP70) mRNA and protein, as well as HSP90 mRNA. However, Zn supplementation increased (P < 0.05) copper zinc superoxide dismutase (CuZnSOD) activity and metallothionein mRNA expression, and effectively decreased (P < 0.05) the expressions of HSP70 mRNA and protein, as well as HSP90 mRNA. Furthermore, oZn was more effective (P < 0.05) than iZn in enhancing CuZnSOD activity of hepatocytes under HT. It was concluded that Zn (especially oZn) could alleviate heat stress of broiler hepatocytes via enhancing their antioxidant ability and attenuating heat shock responses.

Adenosine Receptor and Its Downstream Targets, Mod(mdg4) and Hsp70, Work as a Signaling Pathway Modulating Cytotoxic Damage in Drosophila

Adenosine (Ado) is an important signaling molecule involved in stress responses. Studies in mammalian models have shown that Ado regulates signaling mechanisms involved in “danger-sensing” and tissue-protection. Yet, little is known about the role of Ado signaling in Drosophila. In the present study, we observed lower extracellular Ado concentration and suppressed expression of Ado transporters in flies expressing mutant huntingtin protein (mHTT). We altered Ado signaling using genetic tools and found that the overexpression of Ado metabolic enzymes, as well as the suppression of Ado receptor (AdoR) and transporters (ENTs), were able to minimize mHTT-induced mortality. We also identified the downstream targets of the AdoR pathway, the modifier of mdg4 (Mod(mdg4)) and heat-shock protein 70 (Hsp70), which modulated the formation of mHTT aggregates. Finally, we showed that a decrease in Ado signaling affects other Drosophila stress reactions, including paraquat and heat-shock treatments. Our study provides important insights into how Ado regulates stress responses in Drosophila.

Advances in visualizing transcription factor - DNA interactions

At the heart of the transcription process is the specific interaction between transcription factors (TFs) and their target DNA sequences. Decades of molecular biology research have led to unprecedented insights into how TFs access the genome to regulate transcription. In the last 20 years, advances in microscopy have enabled scientists to add imaging as a powerful tool in probing two specific aspects of TF-DNA interactions: structure and dynamics. In this review, we examine how applications of diverse imaging technologies can provide structural and dynamic information that complements insights gained from molecular biology assays. As a case study, we discuss how applications of advanced imaging techniques have reshaped our understanding of TF behavior across the cell cycle, leading to a rethinking in the field of mitotic bookmarking.

Autophagy is a pro-survival adaptive response to heat shock in bovine cumulus-oocyte complexes

Autophagy is a physiological mechanism that can be activated under stress conditions. However, the role of autophagy during oocyte maturation has been poorly investigated. Therefore, this study characterized the role of autophagy on developmental competence and gene expression of bovine oocytes exposed to heat shock (HS). Cumulus-oocyte-complexes (COCs) were matured at Control (38.5 °C) and HS (41 °C) temperatures in the presence of 0 and 10 mM 3-methyladenine (3MA; autophagy inhibitor). Western blotting analysis revealed that HS increased autophagy marker LC3-II/LC3-I ratio in oocytes. However, there was no effect of temperature for oocytes matured with 3MA. On cumulus cells, 3MA reduced LC3-II/LC3-I ratio regardless of temperature. Inhibition of autophagy during IVM of heat-shocked oocytes (3MA-41 °C) reduced cleavage and blastocyst rates compared to standard in vitro matured heat-shocked oocytes (IVM-41 °C). Therefore, the magnitude of HS detrimental effects was greater in the presence of autophagy inhibitor. Oocyte maturation under 3MA-41 °C reduced mRNA abundance for genes related to energy metabolism (MTIF3), heat shock response (HSF1), and oocyte maturation (HAS2 and GREM1). In conclusion, autophagy is a stress response induced on heat shocked oocytes. Inhibition of autophagy modulated key functional processes rendering the oocyte more susceptible to the deleterious effects of heat shock.

Lin28A Regulates Stem-like Properties of Ovarian Cancer Cells by Enriching RAN and HSBP1 mRNA and Up-regulating its Protein Expression

Ovarian cancer (OC) is one of the malignant tumors that seriously threaten women's health, with the highest mortality rate in gynecological malignancies. The prognosis of patients with advanced OC is still poor, and the 5-year survival rate is only 20-30%. Therefore, how to improve the early diagnosis rate and therapeutic effect are urgent for patients with OC. In this research, we found that Lin28A can promote the expression of stem cell marker molecules CD133, CD44, OCT4 and Nanog. We later confirmed that Lin28A can enrich the mRNA of ras-related nuclear protein (RAN) and heat shock factor binding protein 1 (HSBP1) through RIP assay, and that Lin28A can regulate their protein expression. We also identified that RAN and HSBP1 are highly expressed in OC tissues, and that they are significantly positively correlated with the expression of Lin28A and negatively correlated with the survival prognosis of OC patients. After stable knockdown of RAN or HSBP1 in OC cells with high expression of Lin28A, the expression of the stem cell marker molecules such as OCT4, CD44 and Nanog are reduced. And after knocking down of RAN or HSBP1 in Lin28A highly expressed OC cells, the survival and invasion of OC cells and tumor size of OC xenograft in nude mice were markedly inhibited and apoptosis was increased. Our data also showed that knock down of RAN or HSBP1 can inhibit the invasion ability of OC cells by decreasing the expression of N-cadherin, Vimentin and promoting the expression of E-cadherin. Meanwhile, knockdown of RAN or HSBP1 induced cell apoptosis by inhibiting the expression of PARP. Our results indicated that Lin28A could regulate the biological behaviors in OC cells through RAN/HSBP1. These findings suggest that Lin28A/RAN/HSBP1 can be used as a marker for diagnosis and prognosis of OC patients, and RAN/HSBP1 may be a potential new target for gene therapy of OC.

Immune Responses of the Critically Endangered Yangtze Finless Porpoises (Neophocaena asiaeorientalis ssp. asiaeorientalis) to Escalating Anthropogenic Stressors in the Wild and Seminatural Environments

Increasing anthropogenic stressors are potential threats to biodiversity conservation and management of Yangtze finless porpoises (YFPs). The objective of this study was to indirectly compare the habitat quality of a natural reserve, Poyang Lake and a seminatural reserve, the Tian-E-Zhou Oxbow (TZO) in terms of anthropogenic stressors by investigating different stress and immunological parameters in the blood of YFPs. Samples from a total of 74 YFPs from the TZO (n = 43) and Poyang Lake (n = 31) were collected and analyzed. The animals were divided into ontogenetic groups: male calf, female calf, juvenile female, juvenile male, and adult male, and reproductive groups: pregnant female, lactating female, and pregnant plus lactating. The blood from all the animals was analyzed for general stress (HSP14, SOD1, TXN, and FTL), metabolic stress (ACAT2 and THRA), and immunity-related genes (IL12p40, IFNγ, TNFα; IL1α, IL1ra, COX2, CRPL, IL4, and IL8) using qPCR. YFPs living in Poyang Lake showed an increased relative expression pattern for IFNγ, IL1ra, IL4, ACAT2, and CRPL across all the ontogenetic groups with significantly higher expression in adult males. In contrast, YFPs living in the TZO showed a significantly higher expression in 13 of 15 genes analyzed in the male calf group. Across the reproductive states for porpoises living in Poyang Lake, eight of the 15 genes in the pregnant female and three of the 15 genes in the pregnant plus lactating group had a significantly higher expression level. However, in YFPs living in the TZO, eight of the 15 genes showed significantly higher expression in the pregnant and lactating groups. There was significantly a higher expression of most of the genes in porpoises living in the TZO compared to the age-matched groups from porpoises living in Poyang Lake. The exception was the pregnant female group. The higher relative expression of stress and immune genes in the TZO porpoise population compared to porpoises living in Poyang Lake suggests the effects of worsening habitat quality, possibly indicating water pollution and lack of feeding resources.

HSP-Target of Therapeutic Agents in Sepsis Treatment

Sepsis is a syndrome characterized by a dysregulated inflammatory response, cellular stress, and organ injury. Sepsis is the main cause of death in intensive care units worldwide, creating need for research and new therapeutic strategies. Heat shock protein (HSP) analyses have recently been developed in the context of sepsis. HSPs have a cytoprotection role in stress conditions, signal to immune cells, and activate the inflammatory response. Hence, HSP analyses have become an important focus in sepsis research, including the investigation of HSPs targeted by therapeutic agents used in sepsis treatment. Many therapeutic agents have been tested, and their HSP modulation showed promising results. Nonetheless, the heterogeneity in experimental designs and the diversity in therapeutic agents used make it difficult to understand their efficacy in sepsis treatment. Therefore, future investigations should include the analysis of parameters related to the early and late immune response in sepsis, HSP localization (intra or extracellular), and time to the onset of treatment after sepsis. They also should consider the differences in experimental sepsis models. In this review, we present the main results of studies on therapeutic agents in targeting HSPs in sepsis treatment. We also discuss limitations and possibilities for future investigations regarding HSP modulators.