Molecular chaperone function of mammalian Hsp70 and Hsp40--a review

HSP70-A key regulator in chondrocyte homeostasis under naturally coupled hydrostatic pressure-thermal stimuli

OBJECTIVE

During physical activities, chondrocytes experience coupled stimulation of hydrostatic pressure (HP) and a transient increase in temperature (T), with the latter varying within a physiological range from 32.5 °C to 38.7 °C. Previous short-term in vitro studies have demonstrated that the combined hydrostatic pressure-thermal (HP-T) stimuli more significantly enhance chondroinduction and chondroprotection of chondrocytes than isolated applications. Interestingly, this combined benefit is associated with a corresponding increase in HSP70 levels when HP and T are combined. The current study therefore explored the indispensable role of HSP70 in mediating the combined effects of HP-T stimuli on chondrocytes.

DESIGN

In this mid-long-term study of in vitro engineered cartilage constructs, we assessed chondrocyte responses to HP-T stimuli using customized bioreactor in standard and HSP70-inhibited cultures.

RESULTS

Surprisingly, under HSP70-inhibited conditions, the usually beneficial HP-T stimuli, especially its thermal component, exerted detrimental effects on chondrocyte homeostasis, showing a distinct and unfavorable shift in gene and protein expression patterns compared to non-HSP70-inhibited settings. Such effects were corroborated through mechanical testing and confirmed using a secondary cell source. A proteomic-based mechanistic analysis revealed a disruption in the balance between biosynthesis and fundamental cellular structural components in HSP70-inhibited conditions under HP-T stimuli.

CONCLUSIONS

Our results highlight the critical role of sufficient HSP70 induction in mediating the beneficial effects of coupled HP-T stimulation on chondrocytes. These findings help pave the way for new therapeutic approaches to enhance physiotherapy outcomes and potentially shed light on the elusive mechanisms underlying the onset of cartilage degeneration, a long-standing enigma in orthopedics.

Structural insights into GrpEL1-mediated nucleotide and substrate release of human mitochondrial Hsp70

Maintenance of protein homeostasis is necessary for cell viability and depends on a complex network of chaperones and co-chaperones, including the heat-shock protein 70 (Hsp70) system. In human mitochondria, mitochondrial Hsp70 (mortalin) and the nucleotide exchange factor (GrpEL1) work synergistically to stabilize proteins, assemble protein complexes, and facilitate protein import. However, our understanding of the molecular mechanisms guiding these processes is hampered by limited structural information. To elucidate these mechanistic details, we used cryoEM to determine the first structures of full-length human mortalin-GrpEL1 complexes in previously unobserved states. Our structures and molecular dynamics simulations allow us to delineate specific roles for mortalin-GrpEL1 interfaces and to identify steps in GrpEL1-mediated nucleotide and substrate release by mortalin. Subsequent analyses reveal conserved mechanisms across bacteria and mammals and facilitate a complete understanding of sequential nucleotide and substrate release for the Hsp70 chaperone system.

Cell type-specific regulation of CFTR trafficking-on the verge of progress

Trafficking of the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) protein is a complex process that starts with its biosynthesis and folding in the endoplasmic reticulum. Exit from the endoplasmic reticulum (ER) is coupled with the acquisition of a compact structure that can be processed and traffic through the secretory pathway. Once reaching its final destination-the plasma membrane, CFTR stability is regulated through interaction with multiple protein partners that are involved in its post-translation modification, connecting the channel to several signaling pathways. The complexity of the process is further boosted when analyzed in the context of the airway epithelium. Recent advances have characterized in detail the different cell types that compose the surface epithelium and shifted the paradigm on which cells express CFTR and on their individual and combined contribution to the total expression (and function) of this chloride/bicarbonate channel. Here we review CFTR trafficking and its relationship with the knowledge on the different cell types of the airway epithelia. We explore the crosstalk between these two areas and discuss what is still to be clarified and how this can be used to develop more targeted therapies for CF.

Downregulation of ARNTL in renal tubules of diabetic db/db mice reduces kidney injury by inhibiting ferroptosis

BACKGROUND

The prevalence of ferroptosis in diabetic kidney tubules has been documented, yet the underlying mechanism remains elusive. The aim of this study was to ascertain the pivotal gene linked to ferroptosis and establish a novel target for the prevention and management of diabetic kidney disease (DKD).

METHODS

Transcriptomics data (GSE184836) from DKD mice (C57BLKS/J) were retrieved from the GEO database and intersected with ferroptosis-related genes from FerrDb. Then, differentially expressed genes associated with ferroptosis in the glomeruli and tubules were screened. Gene ontology analysis and protein-protein interaction network construction were used to identify key genes. Western blotting and real-time quantitative polymerase chain reaction were employed to validate the expression in the same model. Aryl hydrocarbon receptor nuclear translocator-like protein 1 (ARNTL) expression in patients and mice with DKD was assessed using immunohistochemistry staining. ARNTL knockdown in C57BLKS/J mice was established and plasma malonaldehyde, superoxide dismutase, and renal pathology were analyzed. The efficacy of ARNTL knockdown was evaluated using proteomics analysis. Mitochondrial morphology was observed using transmission electron microscopy.

RESULTS

ARNTL was screened by bioinformatics analysis and its overexpression verified in patients and mice with DKD. ARNTL knockdown reduced oxidative stress in plasma. Kidney proteomics revealed that ferroptosis was inhibited. The reduction of the classic alteration in mitochondrial morphology associated with ferroptosis was also observed. Gene set enrichment analysis demonstrated that the downregulation of the TGFβ pathway coincided with a decrease in collagen protein and TGFβ1 levels.

CONCLUSIONS

The ferroptosis-associated gene ARNTL is a potential target for treating DKD.

DnaJA2 interacts with Japanese encephalitis virus NS3 via its C-terminal to promote viral infection

Numerous studies have documented that the interaction of viral and cellular proteins is essential in the viral life cycle. In our previous study, to screen cellular proteins that take part in the life cycle of JEV, cellular proteins that interacted with JEV NS3 were identified by Co-immunoprecipitation coupled with mass spectrometry analysis (Co-IP-MS), the results showed that ILF2, DnaJA1, DnaJA2, CKB, TUFM, and PABPC1 that putatively interact with NS3. Another candidate protein, DnaJA2, which interacted with JEV NS3 protein, was selected for further study. Overexpression of DnaJA2 increased JEV infection. Conversely, the knockdown of DnaJA2 suppressed JEV infection. Furthermore, DnaJA2 interacted with NS5 besides NS3 and colocalized with viral dsRNA. Additionally, the level of viral NS3 protein expression was higher in cells overexpressing DnaJA2 than in cells with empty vector expression, whereas DnaJA2 knockdown resulted in NS3 protein degradation, which was subsequently restored by MG132 treatment. Further analysis revealed that the C-terminal of DnaJA2 was a critical domain for interaction with NS3 and promoted JEV infection. Collectively, our study identified DnaJA2 as an essential host factor required for JEV infection, potentially representing a novel therapeutic target for the development of antiviral therapies against JEV.

Genetic architecture of acute hyperthermia resistance in juvenile rainbow trout (Oncorhynchus mykiss) and genetic correlations with production traits

BACKGROUND

Selective breeding is a promising solution to reduce the vulnerability of fish farms to heat waves, which are predicted to increase in intensity and frequency. However, limited information about the genetic architecture of acute hyperthermia resistance in fish is available. Two batches of sibs from a rainbow trout commercial line were produced: the first (N = 1382) was phenotyped for acute hyperthermia resistance at nine months of age and the second (N = 1506) was phenotyped for main production traits (growth, body length, muscle fat content and carcass yield) at 20 months of age. Fish were genotyped on a 57 K single nucleotide polymorphism (SNP) array and their genotypes were imputed to high-density based on the parent's genotypes from a 665 K SNP array.

RESULTS

The heritability estimate of resistance to acute hyperthermia was 0.29 ± 0.05, confirming the potential of selective breeding for this trait. Since genetic correlations of acute hyperthermia resistance with the main production traits near harvest age were all close to zero, selecting for acute hyperthermia resistance should not impact the main production traits, and vice-versa. A genome-wide association study revealed that resistance to acute hyperthermia is a highly polygenic trait, with six quantitative trait loci (QTL) detected, but explaining less than 5% of the genetic variance. Two of these QTL, including the most significant one, may explain differences in acute hyperthermia resistance across INRAE isogenic lines of rainbow trout. Differences in mean acute hyperthermia resistance phenotypes between homozygotes at the most significant SNP was 69% of the phenotypic standard deviation, showing promising potential for marker-assisted selection. We identified 89 candidate genes within the QTL regions, among which the most convincing functional candidates are dnajc7, hsp70b, nkiras2, cdk12, phb, fkbp10, ddx5, cygb1, enpp7, pdhx and acly.

CONCLUSIONS

This study provides valuable insight into the genetic architecture of acute hyperthermia resistance in juvenile rainbow trout. We show that the selection potential for this trait is substantial and selection for this trait should not be too detrimental to improvement of other traits of interest. Identified functional candidate genes provide new knowledge on the physiological mechanisms involved in acute hyperthermia resistance, such as protein chaperoning, oxidative stress response, homeostasis maintenance and cell survival.

Characterisation of the heat shock protein Tid and its involvement in stress response regulation in Apis cerana

Objective: The impact of various environmental stresses on native Apis cerana cerana fitness has attracted intense attention in China. However, the defence responses of A. cerana cerana to different stressors are poorly understood. Here, we aimed to elucidate the regulatory mechanism mediated by the tumorous imaginal discs (Tid) protein of A. cerana cerana (AccTid) in response to stressors. Methods: We used some bioinformatics softwares to analyse the characterisation of Tid. Then, qRT-PCR, RNA interference and heat resistance detection assays were used to explore the function of Tid in stress response in A. cerana cerana. Results: AccTid is a homologous gene of human Tid1 and Drosophila Tid56, contains a conserved J domain and belongs to the heat shock protein DnaJA subfamily. The level of AccTid induced expression was increased under temperature increases from 40°C to 43°C and 46°C, and AccTid knockdown decreased the heat resistance of A. cerana cerana, indicating that the upregulation of AccTid plays an important role when A. cerana cerana is exposed to heat stress. Interestingly, contrary to the results of heat stress treatment, the transcriptional level of AccTid was inhibited by cold, H₂O₂ and some agrochemical stresses and showed no significant change under ultraviolet ray and sodium arsenite stress. These results suggested that the requirement of A. cerana cerana for Tid differs markedly under different stress conditions. In addition, knockdown of AccTid increased the mRNA levels of some Hsps and antioxidant genes. The upregulation of these Hsps and antioxidant genes may be a functional complement of AccTid knockdown. Conclusion: AccTid plays a crucial role in A. cerana cerana stress responses and may mediate oxidative damage caused by various stresses. Our findings will offer fundamental knowledge for further investigations of the defence mechanism of A. cerana cerana against environmental stresses.

The role of heat shock proteins in metastatic colorectal cancer: A review

Heat shock proteins (HSPs) are a large molecular chaperone family classified by their molecular weights, including HSP27, HSP40, HSP60, HSP70, HSP90, and HSP110. HSPs are likely to have antiapoptotic properties and participate actively in various processes such as tumor cell proliferation, invasion, metastases, and death. In this review, we discuss comprehensively the functions of HSPs associated with the progression of colorectal cancer (CRC) and metastasis and resistance to cancer therapy. Taken together, HSPs have numerous clinical applications as biomarkers for cancer diagnosis and prognosis and potential therapeutic targets for CRC and its related metastases.

Characterization of thermo-physiological, hematological, and molecular changes in response to seasonal variations in two tropically adapted native cattle breeds of Bos indicus lineage in hot arid ambience of Thar Desert

The selection of climate resilient animal is necessary to secure the future of sustainable animal production. The present investigation therefore was an effort to unravel answers to the adaptation at physiological, hematological, and molecular levels in cows of hot arid region that helps them to survive harsh environment, to continue production and reproduction. This investigation was carried out in indicine cows over a period of one year, encompassing four seasons, wherein physiological data of 50 animals, hematological data of 15 animals, and gene expression profile of 5 animals from each of Sahiwal and Kankrej breeds per season was generated. In total, 5600 physiological observations, 1344 hematological observations, and 480 molecular samples were processed. The meteorological data revealed a high diurnal variation of temperature across seasons, with THI exceeding 80 during the months of summer and hot-humid seasons, indicating significant heat stress (HS). The physiological parameters showed an increasing trend with the incremental THI, with significantly (p < 0.05) higher values of rectal temperature (RT), respiration rate (RR), pulse rate (PR), and body surface temperature (BST) at ventral (VT), lateral (LT), dorsal (DT), and frontal (FT), in both breeds recorded during HS. The hematological pictures also revealed significant (p < 0.05) seasonal perturbations in erythrocytic and leucocytic parameters. Moreover, the molecular response was driven by a significant (p < 0.05) upregulation of all the key HSPs, HSP70, HSP90, HSP60, and HSP40, except HSP27 during the hotter months of summer and hot-humid seasons. The expression of HSF1, an important transcriptional regulator of  HSP70 was also significantly (p < 0.05) upregulated during summer season in both breeds. All the molecular chaperones revealed a significant upregulation during the summer season, followed by a decreasing trend by hot-humid season. The study indicated a well-developed thermotolerance mechanism in animals of both breeds, with Kankrej cows exhibiting better thermotolerance compared to Sahiwal cows.

Mutation screening of the DNAJC7 gene in Japanese patients with sporadic amyotrophic lateral sclerosis

DNAJC7 has recently been identified as an amyotrophic lateral sclerosis (ALS) gene via large-scale exome analysis, and its involvement in ALS is still unclear in various populations. This study aimed to determine the frequencies and characteristics of the DNAJC7 variants in a Japanese ALS cohort. A total of 807 unrelated Japanese patients with sporadic ALS were screened via exome analysis. In total, we detected six rare missense variants and one splice-site variant of the DNAJC7 gene, which are not reported in the Japanese public database. Furthermore, the missense variants are located around the TPR domain, which is important for the function of DNAJC7. The total frequency of the DNAJC7 variants in Japanese ALS patients was estimated at 0.87%. Collectively, these results suggest that variants of DNAJC7 are rare cause of Japanese patients with sporadic ALS.

Bio-indicators in cadmium toxicity: Role of HSP27 and HSP70

Heat shock proteins (HSPs) are a family of proteins that are expressed by cells in reply to stressors. The changes in concentration of HSPs could be utilized as a bio-indicator of oxidative stress caused by heavy metal. Exposure to the different heavy metals may induce or reduce the expression of different HSPs. The exposure to cadmium ion (Cd²⁺) could increase HSP70 and HSP27 over 2- to 10-fold or even more. The in vitro and in vivo models indicate that the HSP70 family is more sensitive to Cd intoxication than other HSPs. The analyses of other HSPs along with HSP70, especially HSP27, could also be useful to obtain more accurate results. In this regard, this review focuses on examining the literature to bold the futuristic uses of HSPs as bio-indicators in the initial assessment of Cd exposure risks in defined environments.

Cytosolic protein quality control machinery: Interactions of Hsp70 with a network of co-chaperones and substrates

The chaperone heat shock protein 70 (Hsp70) and its network of co-chaperones serve as a central hub of cellular protein quality control mechanisms. Domain organization in Hsp70 dictates ATPase activity, ATP dependent allosteric regulation, client/substrate binding and release, and interactions with co-chaperones. The protein quality control activities of Hsp70 are classified as foldase, holdase, and disaggregase activities. Co-chaperones directly assisting protein refolding included J domain proteins and nucleotide exchange factors. However, co-chaperones can also be grouped and explored based on which domain of Hsp70 they interact. Here we discuss how the network of cytosolic co-chaperones for Hsp70 contributes to the functions of Hsp70 while closely looking at their structural features. Comparison of domain organization and the structures of co-chaperones enables greater understanding of the interactions, mechanisms of action, and roles played in protein quality control.

The Taming of Nuclear Factor Erythroid-2-Related Factor-2 (Nrf2) Deglycation by Fructosamine-3-Kinase (FN3K)-Inhibitors-A Novel Strategy to Combat Cancers

Simple Summary

Aim of this review is to provide an overview on (a) Fructosamine-3-Kinase (FN3K) and its role in regulating Nuclear Factor Erythorid-2-Related Factor-2 (Nrf2); (b) the role of glycation and deglycation mechanisms in modulating the functional properties of proteins, in particular, the Nrf2; (c) the dual role of Nrf2 in the prevention and treatment of cancers. Since controlling the glycation of Nrf2 is one of the key mechanisms determining the fate of a cell; whether to get transformed into a cancerous one or to stay as a normal one, it is important to regulate Nrf2 and deglycating FN3K using pharmacological agents. Inhibitors of FN3K are being explored currently to modulate Nrf2 activity thereby control the cancers.

Abstract

Glycated stress is mediated by the advanced glycation end products (AGE) and the binding of AGEs to the receptors for advanced glycation end products (RAGEs) in cancer cells. RAGEs are involved in mediating tumorigenesis of multiple cancers through the modulation of several downstream signaling cascades. Glycated stress modulates various signaling pathways that include p38 mitogen-activated protein kinase (p38 MAPK), nuclear factor kappa–B (NF-κB), tumor necrosis factor (TNF)-α, etc., which further foster the uncontrolled proliferation, growth, metastasis, angiogenesis, drug resistance, and evasion of apoptosis in several cancers. In this review, a balanced overview on the role of glycation and deglycation in modulating several signaling cascades that are involved in the progression of cancers was discussed. Further, we have highlighted the functional role of deglycating enzyme fructosamine-3-kinase (FN3K) on Nrf2-driven cancers. The activity of FN3K is attributed to its ability to deglycate Nrf2, a master regulator of oxidative stress in cells. FN3K is a unique protein that mediates deglycation by phosphorylating basic amino acids lysine and arginine in various proteins such as Nrf2. Deglycated Nrf2 is stable and binds to small musculoaponeurotic fibrosarcoma (sMAF) proteins, thereby activating cellular antioxidant mechanisms to protect cells from oxidative stress. This cellular protection offered by Nrf2 activation, in one way, prevents the transformation of a normal cell into a cancer cell; however, in the other way, it helps a cancer cell not only to survive under hypoxic conditions but also, to stay protected from various chemo- and radio-therapeutic treatments. Therefore, the activation of Nrf2 is similar to a double-edged sword and, if not controlled properly, can lead to the development of many solid tumors. Hence, there is a need to develop novel small molecule modulators/phytochemicals that can regulate FN3K activity, thereby maintaining Nrf2 in a controlled activation state.

Gene expression in the epileptic (EL) mouse hippocampus

The neuropathology of hippocampal seizure foci in human temporal lobe epilepsy (TLE) and several animal models of epilepsy reveal extensive neuronal loss along with astrocyte and microglial activation. Studies of these models have advanced hypotheses that propose both pathological changes are essential for seizure generation. However, some seizure foci in human TLE show an extreme loss of neurons in all hippocampal fields, giving weight to hypotheses that favor neuroglia as major players. The epileptic (EL) mouse is a seizure model in which there is no observable neuron loss but associated proliferation of microglia and astrocytes and provides a good model to study the role of activated neuroglia in the presence of an apparently normal population of neurons. While many studies have been carried out on the EL mouse, there is a paucity of studies on the molecular changes in the EL mouse hippocampus, which may provide insight on the role of neuroglia in epileptogenesis. In this paper we have applied high throughput gene expression analysis to identify the molecular changes in the hippocampus that may explain the pathological processes. We have observed several classes of genes whose expression levels are changed. It is hypothesized that the upregulation of heat shock proteins (HSP70, HSP72, FOSL2 (HSP40), and their molecular chaperones BAG3 and DNAJB5 along with the down regulated gene MALAT1 may contribute to the neuroprotection observed. The increased expression of BDNF along with immediate early gene expression (FosB, JunB, ERG4, NR4A1, NR4A2, FBXO3) and the down regulation of GABRD, DBP and MALAT1 it is hypothesized may contribute to the hyperexcitability of the hippocampal neurons in this model. Activated astrocytes and microglia may also contribute to excitability pathomechanisms. Activated astrocytes in the ELS mouse are deficient in glutamine synthetase and thus reduce the clearance of extracellular glutamate. Activated microglia which may be associated with C1Q and MHC class I molecules we propose may mediate a process of selective removal of defective GABAergic synapses through a process akin to trogocytosis that may reduce neuronal inhibition and favor hyperexcitability.

Cellular Prion Protein (PrPc): Putative Interacting Partners and Consequences of the Interaction

Cellular prion protein (PrPc) is a small glycosylphosphatidylinositol (GPI) anchored protein most abundantly found in the outer leaflet of the plasma membrane (PM) in the central nervous system (CNS). PrPc misfolding causes neurodegenerative prion diseases in the CNS. PrPc interacts with a wide range of protein partners because of the intrinsically disordered nature of the protein’s N-terminus. Numerous studies have attempted to decipher the physiological role of the prion protein by searching for proteins which interact with PrPc. Biochemical characteristics and biological functions both appear to be affected by interacting protein partners. The key challenge in identifying a potential interacting partner is to demonstrate that binding to a specific ligand is necessary for cellular physiological function or malfunction. In this review, we have summarized the intracellular and extracellular interacting partners of PrPc and potential consequences of their binding. We also briefly describe prion disease-related mutations at the end of this review.

Effect of air pre-exposure on Tetrabromobisphenol A resistance in the clam Ruditapes philippinarum

The present study was conducted to evaluate how air pre-exposure influences the responses in gills and digestive gland of Ruditapes philippinarum on subsequent Tetrabromobisphenol A (TBBPA) exposure. Firstly, clams were maintained in seawater or pre-exposed to air for 24 h, and then exposed to 0 or 100 μg/L TBBPA. Clam tissues were sampled after 1 day (T1) and 7 days (T7) of exposure to TBBPA. The results showed that in comparison with TBBPA exposure alone, air pre-exposure following TBBPA exposure reduced TBBPA accumulation in both tissues, up-regulated mRNA levels of CAT, Hsp70 and pi-GST in gills, and induced GST activity and P-glycoprotein (Pgp) mRNA level in digestive gland of clams at T1, whereas increased lipid peroxidation at T7. Overall, the findings indicate that 24-h exposure to air can activate a priming mechanism withstanding the subsequent TBBPA exposure, which is transient and may change after prolonged subsequent exposure.

HIKESHI silencing can enhance mild hyperthermia sensitivity in human oral squamous cell carcinoma HSC‑3 cells

Hyperthermia (HT) is considered to be of value as a treatment modality in various cancers. However, the acquisition of thermotolerance in cancer cells due to the induction of heat shock proteins (HSPs) makes HT less effective. Recent findings have indicated that heat shock protein nuclear import factor hikeshi (HIKESHI), also referred to as C11orf73, acts as a nuclear import carrier of Hsp70 under heat stress conditions. The aim of the present study was to determine whether knockdown (KD) of HIKESHI by small interfering RNA (siRNA) can potentiate mild HT (MHT) sensitivity in human oral squamous cell carcinoma (OSCC) HSC‑3 cells. The mRNA and protein expression of HIKESHI was found to be markedly suppressed in HSC‑3 cells treated with siRNA for HIKESHI (siHIKE). Silencing HIKESHI significantly decreased the cell viability under MHT conditions (42˚C for 90 min). Immunocytochemical and western blot analyses clearly demonstrated that Hsp70 protein translocated from the cytoplasm to the nucleus under MHT conditions, and this translocation was significantly inhibited in cells treated with siHIKE. Treatment of the cells with MHT transiently increased the phosphorylation level of extracellular signal‑regulated kinase (ERK)2. Furthermore, the phosphorylation was sustained in HIKESHI‑KD cells under MHT conditions, and this sustained phosphorylation was abolished by pretreatment with U0126, an inhibitor of mitogen‑activated protein kinase/ERK. In addition, U0126 significantly decreased the viability of cells treated with the combination of HIKESHI‑KD and MHT. The data of the present study suggest that HIKESHI silencing enhanced the sensitivity of human OSCC HSC‑3 cells to MHT.

Identification of Zinc Absorption Biomarkers in Muscle Tissue of Nile Tilapia Fed with Organic and Inorganic Sources of Zinc Using Metallomics Analysis

The development of metallomics techniques has allowed for metallomics analysis of biological systems, enabling a better understanding of the response mechanisms for different stimuli, their relationship to metallic species, and the characterization of biomarkers. In this study, a metallomics analysis of the muscle tissue of Nile tilapia was used to aid the understanding of the molecular mechanisms involved in zinc absorption in this fish species when fed organic and/or inorganic sources of zinc and to identify possible biomarkers for the absorption of this micromineral. To accomplish this, the fish were separated into three groups of 24 g, 74 g, and 85 g initial weights, and each group, respectively, was fed a zinc-free diet (control group, G1), a diet containing zinc found in organic sources (treatment 1, G2), and a diet containing zinc from an inorganic source (treatment 2, G3). Two-dimensional polyacrylamide (2D PAGE) gel electrophoresis was used to separate the proteins of the muscle tissue. Subsequently, the expression profiles of protein spots in the samples where zinc was applied in different concentrations were compared, using the software ImageMaster 2D Platinum version 7.0, to identify proteins that were differentially expressed. The identified proteins were then exposed to atomic absorption spectrometry in a graphite furnace to determine zinc mapping and were subsequently characterized via electrospray ionization tandem mass spectrometry (ESI-MS/MS). The metallomic analysis identified 15 proteins differentially expressed and associated with zinc, leading to the conclusion that three metal-binding proteins presented as possible biomarkers of zinc absorption in fish.

Roles of Extracellular HSPs as Biomarkers in Immune Surveillance and Immune Evasion

Extracellular heat shock proteins (ex-HSPs) have been found in exosomes, oncosomes, membrane surfaces, as well as free HSP in cancer and various pathological conditions, also known as alarmins. Such ex-HSPs include HSP90 (α, β, Gp96, Trap1), HSP70, and large and small HSPs. Production of HSPs is coordinately induced by heat shock factor 1 (HSF1) and hypoxia-inducible factor 1 (HIF-1), while matrix metalloproteinase 3 (MMP-3) and heterochromatin protein 1 are novel inducers of HSPs. Oncosomes released by tumor cells are a major aspect of the resistance-associated secretory phenotype (RASP) by which immune evasion can be established. The concepts of RASP are: (i) releases of ex-HSP and HSP-rich oncosomes are essential in RASP, by which molecular co-transfer of HSPs with oncogenic factors to recipient cells can promote cancer progression and resistance against stresses such as hypoxia, radiation, drugs, and immune systems; (ii) RASP of tumor cells can eject anticancer drugs, targeted therapeutics, and immune checkpoint inhibitors with oncosomes; (iii) cytotoxic lipids can be also released from tumor cells as RASP. ex-HSP and membrane-surface HSP (mHSP) play immunostimulatory roles recognized by CD91+ scavenger receptor expressed by endothelial cells-1 (SREC-1)+ Toll-like receptors (TLRs)+ antigen-presenting cells, leading to antigen cross-presentation and T cell cross-priming, as well as by CD94+ natural killer cells, leading to tumor cytolysis. On the other hand, ex-HSP/CD91 signaling in cancer cells promotes cancer progression. HSPs in body fluids are potential biomarkers detectable by liquid biopsies in cancers and tissue-damaged diseases. HSP-based vaccines, inhibitors, and RNAi therapeutics are also reviewed.

Reactivation of heat-inactivated Ku proteins by heat shock cognate protein HSC73

PURPOSE

Mouse double-stranded DNA-dependent protein kinase (DNA-PK) activity is heat sensitive. Recovery of heat-inactivated DNA repair activity is a problem after combination therapy with radiation and heat. We investigated the mechanism of recovery of heat-inactivated DNA-PK activity.

METHODS

Hybrid cells containing a fragment of human chromosome 8 in scid cells (RD13B2) were used. DNA-PK activity was measured by an in vitro assay. Immunoprecipitation of the nuclear extract was performed with an anti-Ku80 antibody. Proteins co-precipitated with Ku80 were separated by sodium dodecyl sulfate (SDS) polyacrylamide gel electrophoresis and detected by Western blotting using anti-heat shock protein (HSP)72 and anti-heat shock cognate protein (HSC)73 antibodies. HSC73 was overexpressed with the pcDNA3.1 vector. Short hairpin (sh)RNA was used to downregulate HSC73 and HSP72.

RESULTS

The activity of heat-inactivated DNA-PK recovered to about 50% of control during an additional incubation at 37 °C after heat treatment at 44 °C for 15 min in the presence of cycloheximide (which inhibits de novo protein synthesis). Maximal recovery was observed within 3 h of incubation at 37 °C after heat treatment. Constitutively expressed HSC73, which folds newly synthesized proteins, reached maximal levels 3 h after heat treatment using a co-immunoprecipitation assay with the Ku80 protein. Inhibiting HSC73, but not HSP72, expression with shRNA decreased the recovery of DNA-PK activity after heat treatment.

CONCLUSIONS

These results suggest that de novo protein synthesis is unnecessary for recovery of some heat-inactivated DNA-PK. Rather, it might be reactivated by the molecular chaperone activity of HSC73, but not HSP72.

Molecular cloning, characterization of Pomacea canaliculata HSP40 and its expression analysis under temperature change

Heat shock proteins (HSPs) play important roles in the adaption of Pomacea canaliculata to unsuitable environments. In the present study, a cDNA encoding HSP40 in P. canaliculata (PocaHSP40) was cloned and characterized. The PocaHSP40 cDNA was 1466 bp, containing an ORF of 954 bp encoding 317 amino acids. Bioinformatics analysis showed that PocaHSP40 belonged to type II HSP40s and had four predicted phosphorylation sites. Phylogenetic analysis proved the conservation of HSP40s in mollusks. PocaHSP40 was widely expressed in the gill, digestive gland, kidney, and foot muscle of P. canaliculata. Challenged by different temperatures, the expression of PocaHSP40 was up-regulated under low temperatures but not high temperatures, which was contrary to the expression change of PocaHSP70 under low and high temperatures. These results implied that P. canaliculata evolved different strategies for survival under low temperature and high temperature through the regulation of HSPs.

Transcript profiling in the testes and prostates of postnatal day 30 Sprague-Dawley rats exposed prenatally and lactationally to 2-hydroxy-4-methoxybenzophenone

2-hydroxy-4-methoxybenzophenone (HMB) is an ultraviolet light-absorbing compound that is used in sunscreens, cosmetics and plastics. HMB has been reported to have weak estrogenic activity by in vivo and in vitro studies, making it a chemical with potential reproductive concern. To explore if prenatal and lactational HMB exposure alters gene expression profiles of the developing reproductive organs, we performed microarray analysis using the prostate and testis of postnatal day (PND) 30 male Sprague-Dawley rats offspring exposed to 0, 3000, or 30,000 ppm of HMB from gestational day 6 through PND 21. Gene expression profiles of the prostate and testis were differentially affected by HMB dose with significant alterations observed at the 30,000 ppm HMB group. Tissue-specific gene expression was also identified. These genes, whose expression was altered by HMB exposure, may be considered as candidate biomarker(s) for testicular or prostatic toxicity; however, further studies are necessary to explore this potential.

Differential intracellular localization of Hsp70 in the gill and heart tissue of fresh water prawn Macrobrachium malcolmsonii during thermal stress

Exposure of organisms to heat stress induces the expression of evolutionarily conserved proteins called the stress proteins or heat shock proteins (HSPs). At the cellular level, HSPs by acting as molecular chaperone prevents the heat induced aggregation of denatured proteins and play a significant role in adaptation to temperature. Among different HSP family members, Hsp70 is the highly conserved and ubiquitously expressed protein. The present study is carried out to detect changes in the localization of Hsp70/Hsc70 in gill and heart tissues of control and heat shocked juveniles of Macrobrachium malcolmsonii that could be correlated with the functional significance of these two isoforms. Two groups of prawn acclimated at 30 °C were exposed to reported optimum Hsp70 induction temperatures of 36 °C and 38 °C for heart and gill, respectively, for a duration of 48 h. These tissues were processed by immunocytochemical methods to detect intra-cellular localization of Hsp70/Hsc70. Western blotting analysis was performed to determine the cytoplasmic or nuclear localization of Hsp70/Hsc70 and band intensity was detected in total lysate, cytosolic and nuclear extracts of gill and heart tissue. The present investigation clearly shows that there are alterations in the intracellular localization of Hsp70/Hsc70 in the cells of the gill and heart tissues of M. malcolmsonii following heat stress. The western blotting results corroborate the results obtained by immunohistochemical localisation. The differential intracellular localization of Hsp70/Hsc70 appears to indicate the functional roles of this stress protein during exposure to thermal stress.

Prognostic role of HSPs in human gastrointestinal cancer: a systematic review and meta-analysis

Background

Heat shock proteins (HSPs) have been reported to be overexpressed in a wide range of human tumors. It has been shown that HSPs act as an oncogenic regulator and are involved in tumorigenesis. The clinical and prognostic significance of HSPs in gastrointestinal cancers (GICs) remains controversial. The aim of this study was to conduct a meta-analysis to assess the prognostic value of HSPs in GICs.

Materials and methods

A literature search was performed in PubMed, Cochrane Library, Web of Science, and Embase databases. Data on the relationship between expression of HSPs and survival outcomes were extracted. Pooled hazard ratios (HRs) with 95% CI were calculated.

Results

The expression of HSPs was not associated with the overall survival (OS) of GIC patients; however, it was significantly associated with worse OS for gastric cancer (GC) and colorectal cancer (CRC) patients.

Conclusion

Current evidence suggests that a high level of HSPs may not be a potential marker to predict the survival rate for every type of GICs. However, the expression of HSPs may predict a poor prognosis for GC and CRC patients.

A review of the evidence for threshold of burn injury

INTRODUCTION

Burn injury is common and depth is one measure of severity. Although the depth of burn injury is determined by many factors, the relationship between the temperature of the injurious agent and exposure duration, known as the time-temperature relationship, is widely accepted as one of the cornerstones of burn research. Moritz and Henriques first proposed this relationship in 1947 and their seminal work has been cited extensively. However, over the years, readers have misinterpreted their findings and incorporated misleading information about the time-temperature relationship into a wide range of industrial standards, burn prevention literature and medicolegal opinion.

AIM

The purpose of this paper is to present a critical review of the evidence that relates temperature and time to cell death and the depth of burn injury. These concepts are used by researchers, burn prevention strategists, burn care teams and child protection professionals involved in ascertaining how the mechanism of burning relates to the injury pattern and whether the injury is consistent with the history.

REVIEW METHODS

This review explores the robustness of the currently available evidence. The paper summarises the research from burn damage experimental work as well as bioheat transfer models and discusses the merits and limitations of these approaches.

REVIEW FINDINGS

There is broad agreement between in vitro and in vivo studies for superficial burns. There is clear evidence that the perception of pain in adult human skin occurs just above 43°C. When the basal layer of the epidermis reaches 44°C, burn injury occurs. For superficial dermal burns, the rate of tissue damage increases logarithmically with a linear increase in temperature. Beyond 70°C, rate of damage is so rapid that interpretation can be difficult. Depth of injury is also influenced by skin thickness, blood flow and cooling after injury. There is less clinical evidence for a time-temperature relationship for deep or subdermal burns. Bioheat transfer models are useful in research and becoming increasingly sophisticated but currently have limited practical use. Time-temperature relationships have not been established for burns in children's skin, although standards for domestic hot water suggest that the maximum temperature should be revised downward by 3-4°C to provide adequate burn protection for children.

CONCLUSION

Time-temperature relationships established for pain and superficial dermal burns in adult human skin have an extensive experimental modeling basis and reasonable clinical validation. However, time-temperature relationships for subdermal burns, full thickness burns and burn injury in children have limited clinical validation, being extrapolated from other data, and should be used with caution, particularly if presented during expert evidence.

Identification of Key Genes Affecting Results of Hyperthermia in Osteosarcoma Based on Integrative ChIP-Seq/TargetScan Analysis

Background

The purpose of this study was to research the effects of hyperthermia on osteosarcoma (OS) by integrating the Chromatin Immunoprecipitation with the generation sequencing (ChIP-Seq) and TargetScan analysis of heat shock transcription factor 1 (HSF1).

Material/Methods

The HSF1 ChIP-seq dataset of GSE60984 was downloaded from the Gene Expressed Omnibus (GEO) database. The HSF1-binding sites were screened by MACS2 in OS cells after 10 and 20 min of hyperthermia, and they were annotated using the ChIPseeker package. The overlapped genes were selected out when HSF1-binding sites were located in the promoter region. The Database for Annotation, Visualization, and Integrated Discovery (DAVID) was used to perform Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis of the overlaps. The miRNA-gene pairs of the overlaps were screened out via TargetScan, and the miRNA-gene-regulated network was constructed by Cytoscape software.

Results

1880 and 1283 genes of promoter regions were obtained in the osteosarcoma cells after 10 and 20 min of hyperthermia, respectively, and 889 of them were overlapped. The overlapped genes were enriched in 122 GO terms and 3 KEGG pathways. There were 13 657 pairs involved in the miRNA-gene regulated network of the overlaps.

Conclusions

Some biomarkers were identified for OS treated with hyperthermia. Moreover, some GO terms (regulation of programmed cell death and regulation of cell death) and pathways (p53 signaling pathway, methane metabolism, and viral myocarditis) might be involved.

Heat Shock Protein A2 (HSPA2): Regulatory Roles in Germ Cell Development and Sperm Function

Among the numerous families of heat shock protein (HSP) that have been implicated in the regulation of reproductive system development and function, those belonging to the 70 kDa HSP family have emerged as being indispensable for male fertility. In particular, the testis-enriched heat shock 70 kDa protein 2 (HSPA2) has been shown to be critical for the progression of germ cell differentiation during spermatogenesis in the mouse model. Beyond this developmentally important window, mounting evidence has also implicated HSPA2 in the functional transformation of the human sperm cell during their ascent of the female reproductive tract. Specifically, HSPA2 appears to coordinate the remodelling of specialised sperm domains overlying the anterior region of the sperm head compatible with their principle role in oocyte recognition. The fact that levels of the HSPA2 protein in mature spermatozoa tightly correlate with the efficacy of oocyte binding highlight its utility as a powerful prognostic biomarker of male fertility. In this chapter, we consider the unique structural and biochemical characteristics of HSPA2 that enable this heat shock protein to fulfil its prominent roles in orchestrating the morphological differentiation of male germ cells during spermatogenesis as well as their functional transformation during post-testicular sperm maturation.

HSP70 Modulates the Enhanced Production of Reactive Intermediate Metabolites and a Proinflammatory Cytokine TNF-α Expression in a T Cell Lymphoma

Heat shock proteins are intracellular soluble proteins expressed consecutively in all cells. They are immunogenic proteins able to activate antigen-presenting cells by binding through the CD91 receptor and activate both CD4+ and CD8+ T-cells. Macrophage plays a pivotal role in innate immune response and secretes a number of regulatory molecules upon activation. In the present study, we investigate the activation of normal and tumor-associated macrophage to produce the effector molecules which have a role in immunomodulation, especially in the killing of the transformed or tumor cells. In vitro and in vivo treatment of NMO and TAMs (from T-Cell Lymphoma) with optimum dose 10 μg of hsp70 produce effector molecules such as nitric oxide (NO), hydrogen peroxide (H2O2) and tumor necrosis factor-α (TNF α). The results of our experiments reveal that the production of effector molecules is dose-dependent, and the result of immunoblots also confirms the increased expression of iNOS. These findings suggest that autologous hsp70 are highly immunogenic and potent activating agents for the enhanced production of effector molecules in NMO and TAMs in a T-cell lymphoma.

Network analysis of genes involved in the enhancement of hyperthermia sensitivity by the knockdown of BAG3 in human oral squamous cell carcinoma cells

BCL2-associated athanogene 3 (BAG3), a co-chaperone of the heat shock 70 kDa protein (HSPA) family of proteins, is a cytoprotective protein that acts against various stresses, including heat stress. The aim of the present study was to identify gene networks involved in the enhancement of hyperthermia (HT) sensitivity by the knockdown (KD) of BAG3 in human oral squamous cell carcinoma (OSCC) cells. Although a marked elevation in the protein expression of BAG3 was detected in human the OSCC HSC-3 cells exposed to HT at 44˚C for 90 min, its expression was almost completely suppressed in the cells transfected with small interfering RNA against BAG3 (siBAG) under normal and HT conditions. The silencing of BAG3 also enhanced the cell death that was increased in the HSC-3 cells by exposure to HT. Global gene expression analysis revealed many genes that were differentially expressed by >2-fold in the cells exposed to HT and transfected with siBAG. Moreover, Ingenuity® pathways analysis demonstrated two unique gene networks, designated as Pro-cell death and Anti-cell death, which were obtained from upregulated genes and were mainly associated with the biological functions of induction and the prevention of cell death, respectively. Of note, the expression levels of genes in the Pro-cell death and Anti-cell death gene networks were significantly elevated and reduced in the HT + BAG3-KD group compared to those in the HT control group, respectively. These results provide further insight into the molecular mechanisms involved in the enhancement of HT sensitivity by the silencing of BAG3 in human OSCC cells.

Heat shock proteins in the retina: Focus on HSP70 and alpha crystallins in ganglion cell survival

Heat shock proteins (HSPs) belong to a superfamily of stress proteins that are critical constituents of a complex defense mechanism that enhances cell survival under adverse environmental conditions. Cell protective roles of HSPs are related to their chaperone functions, antiapoptotic and antinecrotic effects. HSPs' anti-apoptotic and cytoprotective characteristics, their ability to protect cells from a variety of stressful stimuli, and the possibility of their pharmacological induction in cells under pathological stress make these proteins an attractive therapeutic target for various neurodegenerative diseases; these include Alzheimer's, Parkinson's, Huntington's, prion disease, and others. This review discusses the possible roles of HSPs, particularly HSP70 and small HSPs (alpha A and alpha B crystallins) in enhancing the survival of retinal ganglion cells (RGCs) in optic neuropathies such as glaucoma, which is characterized by progressive loss of vision caused by degeneration of RGCs and their axons in the optic nerve. Studies in animal models of RGC degeneration induced by ocular hypertension, optic nerve crush and axotomy show that upregulation of HSP70 expression by hyperthermia, zinc, geranyl-geranyl acetone, 17-AAG (a HSP90 inhibitor), or through transfection of retinal cells with AAV2-HSP70 effectively supports the survival of injured RGCs. RGCs survival was also stimulated by overexpression of alpha A and alpha B crystallins. These findings provide support for translating the HSP70- and alpha crystallin-based cell survival strategy into therapy to protect and rescue injured RGCs from degeneration associated with glaucomatous and other optic neuropathies.

AAV-mediated and pharmacological induction of Hsp70 expression stimulates survival of retinal ganglion cells following axonal injury

We evaluated the effect of AAV2- and 17-AAG (17-N-allylamino-17-demethoxygeldanamycin)-mediated upregulation of Hsp70 expression on the survival of retinal ganglion cells (RGCs) injured by optic nerve crush (ONC). AAV2-Hsp70 expression in the retina was primarily observed in the ganglion cell layer. Approximately 75% of all transfected cells were RGCs. RGC survival in AAV2-Hsp70-injected animals was increased by an average of 110% 2 weeks after the axonal injury compared with the control. The increase in cell numbers was not even across the retinas with a maximum effect of approximately 306% observed in the inferior quadrant. 17-AAG-mediated induction of Hsp70 expression has been associated with cell protection in various models of neurodegenerative diseases. We show here that a single intravitreal injection of 17-AAG (0.2 ug ul(-1)) results in an increased survival of ONC-injured RGCs by approximately 49% compared with the vehicle-treated animals. Expression of Hsp70 in retinas of 17-AAG-treated animals was upregulated approximately by twofold compared with control animals. Our data support the idea that the upregulation of Hsp70 has a beneficial effect on the survival of injured RGCs, and the induction of this protein could be viewed as a potential neuroprotective strategy for optic neuropathies.

Levels of metacaspase1 and chaperones related to protein quality control in alcoholic and nonalcoholic steatohepatitis

Efficient management of misfolded or aggregated proteins in ASH and NASH is crucial for continued hepatic viability. Cellular protein quality control systems play an important role in the pathogenesis and progression of ASH and NASH. In a recent study, elevated Mca1 expression counteracted aggregation and accumulation of misfolded proteins and extended the life span of the yeast Saccharomyces cerevisiae (Hill et al, 2014). Mca1 may also associate with Ssa1 and Hsp104 in disaggregation and fragmentation of aggregated proteins and their subsequent degradation through the ER-associated degradation (ERAD) pathway. If degradation is not available, protection of the cellular environment from a misfolded protein is accomplished by its sequestration into two distinct inclusion bodies (Kaganovich et al., 2008) called the JUNQ (JUxta Nuclear Quality control compartment) and the IPOD (Insoluble Protein Deposit). Mca1, Hsp104, Hsp40, Ydj1, Ssa1, VCP/p97, and p62 all play important roles in protein quality control systems. This study aims to measure the expression of Mca1 and related chaperones involved in protein quality control in alcoholic steatohepatitis (ASH), and nonalcoholic steatohepatitis (NASH) compared with normal control liver biopsies. Mca1, Hsp104, Hsp40, Ydj1, Ssa1, VCP/p97, and p62 expressions were measured in three to six formalin-fixed paraffin embedded ASH and NASH liver biopsies and control normal liver specimens by immunofluorescence staining and quantified by immunofluorescence intensity. Mca1, Hsp104, Ydj1 and p62 were significantly upregulated compared to control (p<0.05) in ASH specimens. Hsp40 and VCP/p97 were also uptrending in ASH. In NASH, the only significant difference was the increased expression of Hsp104 compared to control (p<0.05). Ssa1 levels were uptrending in both ASH and NASH specimens. The upregulation of Mca1, Hsp104, Ydj1 and p62 in ASH may be elicited as a response to the chronic exposure of the hepatocytes to the toxicity of alcohol. Recruitment of Mca1, Hsp104, Ydj1 and p62 may indicate that autophagy, the ERAD, JUNQ, and IPOD systems are active in ASH. Whereas in NASH, elevated Hsp104 and uptrending Ssa1 levels may indicate that autophagy and IPOD may be the only active protein quality control systems involved.

BAG3 protects against hyperthermic stress by modulating NF-κB and ERK activities in human retinoblastoma cells

PURPOSE

BCL2-associated athanogene 3 (BAG3), a co-chaperone of HSP70, is a cytoprotective and anti-apoptotic protein that acts against various stresses, including heat stress. Here, we examined the effect of BAG3 on the sensitivity of human retinoblastoma cells to hyperthermia (HT).

METHODS

We examined the effects of BAG3 knockdown on the sensitivity of Y79 and WERI-Rb-1cells to HT (44 °C, 1 h) by evaluating apoptosis and cell proliferation using western blotting, real-time quantitative PCR (qPCR), flow cytometry, and a WST-8 assay kit. Furthermore, we examined the effects of activating nuclear factor-kappa B (NF-κB) and extracellular signal-regulated kinase (ERK) using western blotting and real time qPCR.

RESULTS

HT induced considerable apoptosis along with the activation of caspase-3 and chromatin condensation. The sensitivity of Y79 and WERI-Rb-1 cells to HT was significantly enhanced by BAG3 knockdown. Compared to HT alone, the combination of BAG3 knockdown and HT reduced phosphorylation of the inhibitors of kappa B α (IκBα) and p65, a subunit of NF-κB, and degraded IκB kinase γ (IKKγ) during the recovery period after HT. Furthermore, BAG3 knockdown increased the HT-induced phosphorylation of ERK after HT treatment, and the ERK inhibitor U0126 significantly improved the viability of the cells treated with a combination of BAG3 knockdown and HT.

CONCLUSIONS

The silencing of BAG3 seems to enhance the effects of HT, at least in part, by maintaining HT-induced inactivity of NF-κB and the phosphorylation of ERK. These findings indicate that BAG3 may be a potential molecular target for modifying the outcomes of HT in retinoblastoma.

DNAJB13, a type II HSP40 family member, localizes to the spermatids and spermatozoa during mouse spermatogenesis

BACKGROUND

Hundreds of HSP40s derived from various species have been identified, of which several proteins are involved in spermatogenesis. DNAJB13 is a type II HSP40/DnaJ protein. In a previous study, we cloned mouse Dnajb13, which is up-regulated in cryptorchidism. To date, however, little is known about the localization and functions of DNAJB13 during spermatogenesis. This study intends to identify the expression pattern of DNAJB13 during mammalian spermatogenesis.

RESULTS

RT-PCR and western blot revealed that the Dnajb13 gene and DNAJB13 protein were expressed not only in the testis but also in several other ciliated cell-containing tissues like the trachea, lung and oviduct. Quantitative PCR showed that the expression of Dnajb13 mRNA in testis was detectable as early as postnatal week 1, and sharply increased from postnatal week 3. Western blotting and immunohistochemistry determined that the DNAJB13 protein, which was located in the cytoplasm of spermatids and the sperm flagellum, was detectable from postnatal week 4.

CONCLUSIONS

Based on the spatiotemporal expression observed in the cytoplasm of spermatids and sperm flagella, we suggest that DNAJB13 participates in spermiogenesis and the motility of mature spermatozoa.

CUEDC2 interacts with heat shock protein 70 and negatively regulates its chaperone activity

Recently studies have revealed that CUEDC2, a CUE domain-containing protein, plays critical roles in many biological processes, such as cell cycle, inflammation and tumorigenesis. In this study, to further explore the function of CUEDC2, we performed affinity purification combined with mass spectrometry analysis to identify its interaction proteins, which led to the identification of heat shock protein 70 (HSP70). We confirmed the interaction between CUEDC2 and HSP70 in vivo by co-immunoprecipitation assays. Mapping experiments revealed that CUE domain was required for their binding, while the PBD and CT domains of HSP70, mediated the interaction with CUEDC2. The intracellular Luciferase refolding assay indicated that CUEDC2 could inhibit the chaperone activity of HSP70. Together, our results identify HSP70 as a novel CUEDC2 interaction protein and suggest that CUEDC2 might play important roles in regulating HSP70 mediated stress responses.

HSP40 interacts with pyruvate kinase M2 and regulates glycolysis and cell proliferation in tumor cells

Pyruvate kinase M2 (PKM2) is predominantly expressed in cancers, which is considered as a key regulator of the Warburg effect. In this study, HSP40 was identified as a novel binding partner of PKM2. HSP40-PKM2 association destabilized PKM2 protein through HSC70. In the presence of HSP40, PKM2 protein level and PKM2-mediated PDK1 expression were down-regulated. Moreover, HSP40 was involved in regulating glucose metabolism on PKM2 dependent way and at the mean time had an effect on mitochondrial oxygen respiration. In line with inhibition effect of HSP40 on glycolysis, the growth of cancer cells was inhibited by HSP40.Our data provided a new regulation mechanism of PKM2, which suggested a new therapeutic target for cancer therapy.

Toll-like receptor-2 mediates adaptive cardiac hypertrophy in response to pressure overload through interleukin-1β upregulation via nuclear factor κB activation

BACKGROUND

Inflammation is induced in the heart during the development of cardiac hypertrophy. The initiating mechanisms and the role of inflammation in cardiac hypertrophy, however, remain unclear. Toll-like receptor-2 (TLR2) recognizes endogenous molecules that induce noninfectious inflammation. Here, we examined the role of TLR2-mediated inflammation in cardiac hypertrophy.

METHODS AND RESULTS

At 2 weeks after transverse aortic constriction, Tlr2(-/-) mice showed reduced cardiac hypertrophy and fibrosis with greater left ventricular dilatation and impaired systolic function compared with wild-type mice, which indicated impaired cardiac adaptation in Tlr2(-/-) mice. Bone marrow transplantation experiment revealed that TLR2 expressed in the heart, but not in bone marrow-derived cells, is important for cardiac adaptive response to pressure overload. In vitro experiments demonstrated that TLR2 signaling can induce cardiomyocyte hypertrophy and fibroblast and vascular endothelial cell proliferation through nuclear factor-κB activation and interleukin-1β upregulation. Systemic administration of a nuclear factor-κB inhibitor or anti-interleukin-1β antibodies to wild-type mice resulted in impaired adaptive cardiac hypertrophy after transverse aortic constriction. We also found that heat shock protein 70, which was increased in murine plasma after transverse aortic constriction, can activate TLR2 signaling in vitro and in vivo. Systemic administration of anti-heat shock protein 70 antibodies to wild-type mice impaired adaptive cardiac hypertrophy after transverse aortic constriction.

CONCLUSIONS

Our results demonstrate that TLR2-mediated inflammation induced by extracellularly released heat shock protein 70 is essential for adaptive cardiac hypertrophy in response to pressure overload. Thus, modulation of TLR2 signaling in the heart may provide a novel strategy for treating heart failure due to inadequate adaptation to hemodynamic stress.

Expression and significance of HMGB1, TLR4 and NF-κB p65 in human epidermal tumors

Background

High mobility group protein box 1 (HMGB1) is a DNA binding protein located in nucleus. It is released into extracellular fluid where it acts as a novel proinflammatory cytokine which interacts with Toll like receptor 4 (TLR4) to activate nuclear factor-κB (NF-κB). This sequence of events is involved in tumor growth and progression. However, the effects of HMGB1, TLR4 and NF-κB on epidermal tumors remain unclear.

Methods

Human epidermal tumor specimens were obtained from 96 patients. Immunohistochemistry was used to detect expression of HMGB1, TLR4 and NF-κB p65 in human epidermal tumor and normal skin specimens. Western blot analysis was used to detect the expression of NF-κB p65 in epithelial cell nuclei in human epidermal tumor and normal tissues.

Results

Immunohistochemistry and western blot analysis indicated a progressive but statistically significant increase in p65 expression in epithelial nuclei in benign seborrheic keratosis (SK), precancerous lesions (PCL), low malignancy basal cell carcinoma (BCC) and high malignancy squamous cell carcinoma (SCC) (P <0.01). The level of extracellular HMGB1 in SK was significantly higher than in normal skin (NS) (P <0.01), and was higher than in SCC but without statistical significance. The level of TLR4 on epithelial membranes of SCC cells was significantly higher than in SK, PCL, BCC and NS (P <0.01). There was a significant positive correlation between p65 expression in the epithelial nuclei and TLR4 expression on the epithelial cell membranes (r = 0.3212, P <0.01).

Conclusions

These findings indicate that inflammation is intensified in parallel with increasing malignancy. They also indicate that the TLR4 signaling pathway, rather than HMGB1, may be the principal mediator of inflammation in high-grade malignant epidermal tumors. Combined detection of p65 in the epithelial nuclei and TLR4 on the epithelial membranes may assist the accurate diagnosis of malignant epidermal tumors.

Morphological effects of autologous hsp70 on peritoneal macrophages in a murine T cell lymphoma

Heat shock protein 70 is highly conserved cytosolic protein which have important role in growth, development, and apoptosis. Hsp70 is well-known activator of macrophages and enhances the release of specific and non-specific effector molecules that have major role in tumor destruction and immunopotentiation of host. However, morphological effects of hsp 70 has not been carried out, therefore, morphological effects of hsp 70 on murine peritoneal macrophages were examined by light microscopy and scanning electron microscopy. Thioglycolate-induced peritoneal macrophages were prepared from BALB/c mice and cultured for 24 h in the presence of the hsp70. Tumor-associated macrophages treated with 10 μg/ml were varied in shape, mostly spindle shaped, i.e., stretched bidirectionally; surface ruffles were increased and their lamellipodia was prominent which suggest that hsp 70 treatment not only enhances the functional state of the peritoneal macrophages but also initiate immense morphological changes leading to increased endothelium adherence, increased antigen uptake, and increased migration to the inflammatory site.

Temperature-dependent, behavioural, and transcriptional variability of a tritrophic interaction consisting of bean, herbivorous mite, and predator

Different organisms compensate for, and adapt to, environmental changes in different ways. In this way, environmental changes affect animal-plant interactions. In this study, we assessed the effect of temperature on a tritrophic system of the lima bean, the herbivorous spider mite Tetranychus urticae and the predatory mite Phytoseiulus persimilis. In this system, the plant defends itself against T. urticae by emitting volatiles that attract P. persimilis. Over 20-40 °C, the emission of volatiles by infested plants and the subsequent attraction of P. persimilis peaked at 30 °C, but the number of eggs laid by T. urticae adults and the number of eggs consumed by P. persimilis peaked at 35 °C. This indicates that the spider mites and predatory mites performed best at a higher temperature than that at which most volatile attractants were produced. Our data from transcriptome pyrosequencing of the mites found that P. persimilis up-regulated gene families for heat shock proteins (HSPs) and ubiquitin-associated proteins, whereas T. urticae did not. RNA interference-mediated gene suppression in P. persimilis revealed differences in temperature responses. Predation on T. urticae eggs by P. persimilis that had been fed PpHsp70-1 dsRNA was low at 35 °C but not at 25 °C when PpHsp70-1 expression was very high. Overall, our molecular and behavioural approaches revealed that the mode and tolerance of lima bean, T. urticae and P. persimilis are distinctly affected by temperature variability, thereby making their tritrophic interactions temperature dependent.

Exposure of Wistar rats to 24-h psycho-social stress alters gene expression in the inferior colliculus

Recently, we have demonstrated that the exposure of Wistar rats to psycho-social stress results in a transient auditory hypersensitivity. Here, to learn more about modifications occurring in auditory brainstem, we have analyzed gene expression pattern in inferior colliculus using quantitative RT-PCR. As targets, we have chosen genes associated with: neural activity (FBJ osteosarcoma viral oncogene, cFos), hypoxia (nitric oxide synthase inducible, iNos; superoxide dismutase 2, Sod2), neuroprotection (nerve growth factor beta, Ngfb; heat shock factor 1, Hsf1; heat shock protein 70, Hsp70) and inflammation (tumor necrosis factor alpha, Tnfa; tumor necrosis factor alpha receptor, Tnfar; substance P, Sp; cyclooxygenase 2, Cox2). We found that the expression of all genes was modified following stress, as compared to the controls. Immediately after stress, the number of transcripts encoding iNos, Sod2, Hsf1, Ngfb, Tnfa, Tnfar and Sp was significantly increased, suggesting possible modulation during exposure to stressor. Interestingly, we found that expression of Hsf1 and Ngfb at this particular time was left-right asymmetrical: there were more transcripts of both genes found in the left colliculi, as compared to the right colliculi. Three hours post-stress, iNos, Hsf1, Tnfa and Tnfar were still upregulated, Sod2, Ngfb and Sp went back to baseline and Cox2 was upregulated. Six hours post-stress, cFos mRNA became downregulated. The number of Hsp70 mRNA increased 24h post-stress. Except for the reduced number of cFos transcripts, expression of all other genes tested reached the baseline seven days post-stress. Presented results corroborate the concept of auditory system responding to the psycho-social stress. Post-stress changes in the IC gene expression could likely indicate shift from allostasis to homeostasis in the auditory brainstem.