Insights into regulation and function of the major stress-induced hsp70 molecular chaperone in vivo: analysis of mice with targeted gene disruption of the hsp70.1 or hsp70.3 gene

Testicular expression of heat SHOCK proteins 60, 70, and 90 in cryptorchid horses

Heat shock proteins are the most evolutionarily conserved protein families induced by stressors including hyperthermia. In the context of pathologies of the male reproductive tract, cryptorchidism is the most common genital defect that compromises the reproductive potential of the male because it induces an increase in intratesticular temperature. In equine species, cryptorchidism affects almost 9 % of newborns and few studies have been carried out on the molecular aspects of the retained testis. In this study, the expression pattern of HSP60, 70, and 90 in abdominal and inguinal testes, in their contralateral descended normally testes, and in testes of normal horses were investigated by Western blot and immunohistochemistry. The histomorphological investigation of retained and scrotal testes was also investigated. The seminiferous epithelium of the retained testes showed a vacuolized appearance and displayed a completely blocked spermatogenesis for lacking meiotic and spermiogenetic cells. On the contrary, the contralateral scrotal testes did not show morphological damage and the seminiferous epithelium displayed all phases of the spermatogenetic cycle as in the normal testes. The morphology of Leydig cells was not affected by the cryptorchid state. Western blot and immunohistochemistry evidenced that equine testis (both scrotal and retained) expresses the three investigated HSPs. More in detail, the Western blot evidenced that HSP70 is the more expressed chaperone and that together with HSP90 it is highly expressed in the retained gonad (P < 0.05). The immunohistochemistry revealed the presence of the three HSPs in the spermatogonia of normal and cryptorchid testes. Spermatogonia of retained testes showed the lowest expression of HSP60 and the highest expression of HSP90. Spermatocytes, spermatids of scrotal testes, and the Sertoli cells of retained and scrotal testes did not display HSP60 whereas expressed HSP70 and HSP90. These two proteins were also localized in the nucleus of the premeiotic cells. The Leydig cells displayed the three HSPs with the higher immunostaining of HSP70 and 90 in the cryptorchid testes. The results indicate that the heat stress condition occurring in the cryptorchid testis influences the expression of HSPs.

The Emerging Landscape for Combating Resistance Associated with Energy-Based Therapies via Nanomedicine

Cancer represents a serious disease with significant implications for public health, imposing substantial economic burden and negative societal consequences. Compared to conventional cancer treatments, such as surgery and chemotherapy, energy-based therapies (ET) based on athermal and thermal ablation provide distinct advantages, including minimally invasive procedures and rapid postoperative recovery. Nevertheless, due to the complex pathophysiology of many solid tumors, the therapeutic effectiveness of ET is often limited. Nanotechnology offers unique opportunities by enabling facile material designs, tunable physicochemical properties, and excellent biocompatibility, thereby further augmenting the outcomes of ET. Numerous nanomaterials have demonstrated the ability to overcome intrinsic therapeutic resistance associated with ET, leading to improved antitumor responses. This comprehensive review systematically summarizes the underlying mechanisms of ET-associated resistance (ETR) and highlights representative applications of nanoplatforms used to mitigate ETR. Overall, this review emphasizes the recent advances in the field and presents a detailed account of novel nanomaterial designs in combating ETR, along with efforts aimed at facilitating their clinical translation.

Puerarin inhibits inflammation and oxidative stress in female BALB/c mouse models of Graves' disease

Background

Graves' disease (GD) is an autoimmune thyroid disorder. Our previous study has demonstrated a significant decrease in flavone levels among children with GD compared to the control group. Puerarin, a well-known flavonoid with anti-inflammatory and antioxidant properties. We wanted to investigate its potential impact on GD pathogenesis, aiming to determine whether increasing puerarin intake could prevent or delay the onset of GD.

Methods

Adenovirus with TSHR-289 subunit was used to establish a GD mice model, and mice were intragastrically administered with puerarin or sterilized water daily. Thyroid function and inflammatory cytokine levels were quantified using ELISA, lymphocyte subsets were analyzed via flow cytometry, oxidative stress (OS) markers were measured with a microplate reader, and the expression of pertinent signaling pathway proteins were assessed by Western blot.

Results

The results demonstrated that puerarin treatment significantly decreased thyroxin levels and alleviated thyroid pathological changes in GD mice. Furthermore, the immune imbalance of GD mice was improved, as evidenced by reduced inflammatory indexes, elevated antioxidant levels, and decreased malondialdehyde (MDA) levels compared to untreated GD mice. Puerarin-treated GD mice exhibited significantly lower expressions of heat shock protein (HSP): HSP70, HSP90, phosphorylated extracellular regulated kinases (p-ERK) and phosphorylated protein kinase B (p-AKT) than untreated GD mice. Moreover, low dosage puerarin (400 mg/kg) was associated with a better protective effect than high dosage (1,200 mg/kg).

Conclusions

Puerarin may have the potential to mitigate GD by inhibiting inflammatory and OS, through downregulating the expression of HSP70 and HSP90 and suppressing the activation of the PI3K/AKT/ERK signaling pathway. Furthermore, a lower dose exhibited superior protective effects compared to a higher dose.

Advances in Brain Tumor Therapy Based on the Magnetic Nanoparticles

Brain tumors, including primary gliomas and brain metastases, are one of the deadliest tumors because effective macromolecular antitumor drugs cannot easily penetrate the blood-brain barrier (BBB) and blood-brain tumor barrier (BTB). Magnetic nanoparticles (MNPs) are considered the most suitable nanocarriers for the delivery of brain tumor drugs because of their unique properties compared to other nanoparticles. Numerous preclinical and clinical studies have demonstrated the potential of these nanoparticles in magnetic targeting, nuclear magnetic resonance, magnetic thermal therapy, and ultrasonic hyperthermia. To further develop and optimize MNPs for the diagnosis and treatment of brain tumors, we attempt to outline recent advances in the use of MNPs to deliver drugs, with a particular focus on their efficacy in the delivery of anti-brain tumor drugs based on magnetic targeting and low-intensity focused ultrasound, magnetic resonance imaging for surgical real-time guidance, and magnetothermal and ultrasonic hyperthermia therapy. Furthermore, we summarize recent findings on the clinical application of MNPs and the research limitations that need to be addressed in clinical translation.

Fractionated Sonodynamic Therapy Using Gold@Poly(ortho-aminophenol) Nanoparticles and Multistep Low-Intensity Ultrasound Irradiation to Treat Melanoma Cancer: In Vitro and In Vivo Studies

OBJECTIVE

Cancer treatment using ultrasound irradiation with low intensities along with a sonosensitizer has been found to have significant advantages, such as high penetration depth in tissues, non-invasive therapeutic character, minor side effects, good patient adherence and preferential tumor area treatment. In the present study, gold nanoparticles covered by poly(ortho-aminophenol) (Au@POAP NPs) were synthesized and characterized as a new sonosensitizer.

METHODS

We investigated Au@POAP NPs efficacy on fractionated ultrasound irradiation for treatment of melanoma cancer in vitro as well as in vivo.

DISCUSSION

In vitro examinations revealed that although Au@POAP NPs (with a mean size of 9.8 nm) alone represented concentration-dependent cytotoxicity against the B16/F10 cell line, multistep ultrasound irradiation (1 MHz frequency, 1.0 W/cm² intensity, 60 s irradiation time) of the cells in the attendance of Au@POAP NPs led to efficient cell sonodynamic therapy (SDT) and death. Histological analyses revealed that in vivo fractionated SDT toward melanoma tumors of male balb/c mice led to no residual viable tumor cell after 10 d.

CONCLUSION

A deep sonosensitizing effectiveness of Au@POAP NPs on fractionated low-intensity ultrasound irradiation was attained with the main mechanism of tumor cell eradication of promotion of apoptosis or necrosis through dramatically increased reactive oxygen species levels.

The human cumulus cell transcriptome provides poor predictive value for embryo transfer outcome

RESEARCH QUESTION

Is the transcriptome of cumulus cells a good predictor of the embryo's developmental competence?

DESIGN

Cumulus cells were collected from donor oocytes and their transcriptome was analysed by RNA sequencing analysis at >30 × 10⁶ reads in samples grouped according to the developmental potential of their enclosed oocyte: not able to develop to the blastocyst stage (Bl-), able to develop to the blastocyst stage but failing to establish a pregnancy (P-), or able to develop to the blastocyst stage and to establish a clinical pregnancy (P+).

RESULTS

The cumulus cell trancriptome was largely independent of the developmental potential as, using a false dscovery rate-adjusted P-value of <0.05, only 10, 11 and 5 genes were differentially expressed for the comparisons P+ versus P-, P+ versus Bl-, and P- versus Bl-, respectively, out of a total of 17,469 genes expressed. Between the differentially expressed genes, those showing little overlap between samples from different groups were CHAC1, up-regulated in the P- and P+ groups compared with the Bl- group, and CENPE, CD93, PECAM1 and HSPA1B, which showed the opposite expression pattern. Focusing on the pregnancy potential, only EPN3 was consistently downregulated in the P+ compared with the P- and Bl- groups.

CONCLUSIONS

The cumulus cell transcriptome is largely unrelated to the establishment of clinical pregnancy following embryo transfer, although the expression level of a subset of genes in cumulus cells may indicate the ability to develop to the blastocyst stage.

Effect of acute heat shock on stress gene expression and DNA methylation in zebu (Bos indicus) and crossbred (Bos indicus × Bos taurus) dairy cattle

Environmental temperature is one of the major factors to affect health and productivity of dairy cattle. Gene expression networks within the cells and tissues coordinate stress response, metabolism, and milk production in dairy cattle. Epigenetic DNA methylations were found to mediate the effect of environment by regulating gene expression patterns. In the present study, we compared three Indian native zebu cattle, Bos indicus (Sahiwal, Tharparkar, and Hariana) and one crossbred Bos indicus × Bos taurus (Vrindavani) for stress gene expression and differences in the DNA methylation patterns. The results indicated acute heat shock to cultured PBMC affected their proliferation, stress gene expression, and DNA methylation. Interestingly, expressions of HSP70, HSP90, and STIP1 were found more pronounced in zebu cattle than the crossbred cattle. However, no significant changes were observed in global DNA methylation due to acute heat shock, even though variations were observed in the expression patterns of DNA methyltransferases (DNMT1, DNMT3a) and demethylases (TET1, TET2, and TET3) genes. The treatment 5-AzaC (5-azacitidine) that inhibit DNA methylation in proliferating PBMC caused significant increase in heat shock-induced HSP70 and STIP1 expression indicating that hypomethylation facilitated stress gene expression. Further targeted analysis DNA methylation in the promoter regions revealed no significant differences for HSP70, HSP90, and STIP1. However, there was a significant hypomethylation for BDNF in both zebu and crossbred cattle. Similarly, NR3C1 promoter region showed hypomethylation alone in crossbred cattle. Overall, the results indicated that tropically adapted zebu cattle had comparatively higher expression of stress genes than the crossbred cattle. Furthermore, DNA methylation may play a role in regulating expression of certain genes involved in stress response pathways.

An Ethanolic Extract of Cucurbita pepo L. Seeds Modifies Neuroendocrine Disruption in Chronic Stressed Rats and Adrenal Expression of Inflammatory Markers and HSP70

Background: Pumpkins (Cucurbita pepo L.) were described to have antioxidant, anti-inflammatory, anti-fatigue, and antidepressant-like effect. The adrenal gland is an important stress-responsive organ that maintains homeostasis during stress.

Objectives: This study aimed to assess the efficacy of the administration of Cucurbita pepo L. (CP) extract in relieving behavioral, biochemical, and structural changes in the adrenal gland induced by exposure to chronic unpredictable mild stress (CUMS) and to explore the mechanism behind this impact.

Materials and Methods: Forty male albino rats were divided into 4 groups (n = 10): control, CUMS, fluoxetine-treated, and CP-treated groups. Behavioral changes, corticosterone level, pro-inflammatory cytokines TNF-α and IL-6, and oxidant/antioxidant profile were assessed in the serum at the end of the experiment. Adrenal glands were processed for histopathological and immunohistochemical assessment. Gene expression of caspase-3 and Ki67 and heat shock protein 70 (HSP70) were assessed in adrenal glands using RT-PCR.

Results: The CP extract significantly reduced the corticosterone level (p < 0.001), immobility time (p < 0.001), and inflammatory and oxidative changes associated with CUMS-induced depression compared to the untreated group. The CP extract alleviated CUMS-induced adrenal histopathological changes and significantly reduced apoptosis (p < 0.001) and significantly upregulated antioxidant levels in the serum.

Conclusion:Cucurbita pepo L. effectively ameliorated the chronic stress-induced behavioral, biochemical, and adrenal structural changes mostly through its antioxidant and anti-inflammatory effects.

Stoichiometric Analysis of Shifting in Subcellular Compartmentalization of HSP70 within Ischemic Penumbra

The heat shock protein (HSP) 70 is considered the main hallmark in preclinical studies to stain the peri-infarct region defined area penumbra in preclinical models of brain ischemia. This protein is also considered as a potential disease modifier, which may improve the outcome of ischemic damage. In fact, the molecule HSP70 acts as a chaperonine being able to impact at several level the homeostasis of neurons. Despite being used routinely to stain area penumbra in light microscopy, the subcellular placement of this protein within area penumbra neurons, to our knowledge, remains undefined. This is key mostly when considering studies aimed at deciphering the functional role of this protein as a determinant of neuronal survival. The general subcellular placement of HSP70 was grossly reported in studies using confocal microscopy, although no direct visualization of this molecule at electron microscopy was carried out. The present study aims to provide a direct evidence of HSP70 within various subcellular compartments. In detail, by using ultrastructural morphometry to quantify HSP70 stoichiometrically detected by immuno-gold within specific organelles we could compare the compartmentalization of the molecule within area penumbra compared with control brain areas. The study indicates that two cell compartments in control conditions own a high density of HSP70, cytosolic vacuoles and mitochondria. In these organelles, HSP70 is present in amount exceeding several-fold the presence in the cytosol. Remarkably, within area penumbra a loss of such a specific polarization is documented. This leads to the depletion of HSP70 from mitochondria and mostly cell vacuoles. Such an effect is expected to lead to significant variations in the ability of HSP70 to exert its physiological roles. The present findings, beyond defining the neuronal compartmentalization of HSP70 within area penumbra may lead to a better comprehension of its beneficial/detrimental role in promoting neuronal survival.

Loss of DIAPH3, a Formin Family Protein, Leads to Cytokinetic Failure Only under High Temperature Conditions in Mouse FM3A Cells

Cell division is essential for the maintenance of life and involves chromosome segregation and subsequent cytokinesis. The processes are tightly regulated at both the spatial and temporal level by various genes, and failures in this regulation are associated with oncogenesis. Here, we investigated the gene responsible for defects in cell division by using murine temperature-sensitive (ts) mutant strains, tsFT101 and tsFT50 cells. The ts mutants normally grow in a low temperature environment (32 °C) but fail to divide in a high temperature environment (39 °C). Exome sequencing and over-expression analyses identified Diaph3, a member of the formin family, as the cause of the temperature sensitivity observed in tsFT101 and tsFT50 cells. Interestingly, Diaph3 knockout cells showed abnormality in cytokinesis at 39 °C, and the phenotype was rescued by re-expression of Diaph3 WT, but not Diaph1 and Diaph2, other members of the formin family. Furthermore, Diaph3 knockout cells cultured at 39 °C showed a significant increase in the level of acetylated α-tubulin, an index of stabilized microtubules, and the level was reduced by Diaph3 expression. These results suggest that Diaph3 is required for cytokinesis only under high temperature conditions. Therefore, our study provides a new insight into the mechanisms by which regulatory factors of cell division function in a temperature-dependent manner.

The heat shock protein family gene Hspa1l in male mice is dispensable for fertility

Background

Heat shock protein family A member 1 like (Hspa1l) is a member of the 70kD heat shock protein (Hsp70) family. HSPA1L is an ancient, evolutionarily conserved gene with a highly conserved domain structure. The gene is highly abundant and constitutively expressed in the mice testes. However, the role of Hspa1l in the testes has still not been elucidated.

Methods

Hspa1l-mutant mice were generated using the CRISPR/Cas9 system. Histological and immunofluorescence staining were used to analyze the phenotypes of testis and epididymis. Apoptotic cells were detected through TUNEL assays. Fertility and sperm motilities were also tested. Quantitative RT-PCR was used for analyzing of candidate genes expression. Heat treatment was used to induce heat stress of the testis.

Results

We successfully generated Hspa1l knockout mice. Hspa1l ^-/- mice exhibited normal development and fertility. Further, Hspa1l ^-/- mice shown no significant difference in spermatogenesis, the number of apoptotic cells in testes epididymal histology, sperm count and sperm motility from Hspa1l ^+/+ mice. Moreover, heat stress does not exacerbate the cell apoptosis in Hspa1l ^-/- testes. These results revealed that HSPA1L is not essential for physiological spermatogenesis, nor is it involved in heat-induced stress responses, which provides a basis for further studies.

Evaluating cytotoxicity of methyl benzoate in vitro

Methyl benzoate (MB) is a small, hydrophobic organic compound that is isolated from the freshwater fern, Salvinia molesta. Because of its pleasant odor, it has been used as a fragrance and flavor enhancer. In addition, it is used to attract orchid bees for pollination in the farm and has been tested for its potential to be developed as a green pesticide targeting a diverse group of insects. In spite of its wide applications, the safety of MB to humans remains poorly understood. In this study, we tested the cytotoxicity of MB against cultured human cells, including kidney, colon, and neuronal cells. Furthermore, other natural and synthetic benzoic acids such as ethyl benzoate (EB) and vinyl benzoate (VB) were compared with MB for their similarity and broad commercial and industrial applications. We found that MB and VB have the least and most overall toxicity to the tested human cells, respectively. In addition, the expression of some genes involved in cell cycle, protein quality control, and neurotransmission such as cyclin D1, HSP70, and ACHE genes was differentially expressed in the presence of these chemicals, most noticeably in treatment of VB. Our study provided the LC₅₀ values of these benzoic acids for human cells in vitro and suggested their mild toxicity that should be considered in the industrial and agricultural applications to be within safe limits.

Enhanced Tumor Synergistic Therapy by Injectable Magnetic Hydrogel Mediated Generation of Hyperthermia and Highly Toxic Reactive Oxygen Species

Nanoparticle-mediated tumor magnetic induction hyperthermia has received tremendous attention. However, it has been a challenge to improve the efficacy at 42 °C therapeutic temperatures without resistance to induced thermal stress. Therefore, we designed a magnetic hydrogel nanozyme (MHZ) utilizing inclusion complexation between PEGylated nanoparticles and α-cyclodextrin, which can enhance tumor oxidative stress levels by generating reactive oxygen species through nanozyme-catalyzed reactions based on tumor magnetic hyperthermia. MHZ can be injected and diffused into the tumor tissue due to shear thinning as well as magnetocaloric phase transition properties, and magnetic heat generated by the Fe₃O₄ first gives 42 °C of hyperthermia to the tumor. Fe₃O₄ nanozyme exerts peroxidase-like properties in the acidic environment of tumor to generate hydroxyl radicals (^•OH) by the Fenton reaction. The hyperthermia promotes the enzymatic activity of Fe₃O₄ nanozyme to produce more ^•OH. Simultaneously, ^•OH further damages the protective heat shock protein 70, which is highly expressed in hyperthermia to enhance the therapeutic effect of hyperthermia. This single magnetic nanoparticle exerts dual functions of hyperthermia and catalytic therapy to synergistically treat tumors, overcoming the resistance of tumor cells to induced thermal stress without causing severe side effects to normal tissues at 42 °C hyperthermia.

Physiological response of fish under variable acidic conditions: a molecular approach through the assessment of an eco-physiological marker in the brain

The current study demonstrates oxidative damage and associated neurotoxicity following pH stress in two freshwater carp Labeo rohita and Cirrhinus cirrhosus. Carp (n = 6, 3 replicates) were exposed to four different pH (5.5, 6, 7.5, and 8) against control (pH 6.8 ± 0.05) for 7 days. After completion of treatment, levels of enzymatic (superoxide dismutase [SOD], catalase [CAT], glutathione reductase [GRd]) and non-enzymatic antioxidants (malondialdehyde [MDA], glutathione [GSH]), brain neurological parameters (Na⁺-K⁺ATPase, acetylcholinesterase [AcHE], monoamine oxidase [MAO], and nitric oxide [NO]), xanthine oxidase (XO), heat shock proteins (HSP70 and HSP90), and transcription factor NFkB were measured in carp brain. Variation in the pH caused a significant alteration in the glutathione system (glutathione and glutathione reductase), SOD-CAT system, and stress marker malondialdehyde (MDA). Xanthine oxidase was also induced significantly after pH exposure. Brain neurological parameters (MAO, NO, AChE, and Na⁺-K⁺ATPase) were significantly reduced at each pH-treated carp group though inhibition was highest at lower acidic pH (5.5). Cirrhinus cirrhosus was more affected than that of Labeo rohita. Molecular chaperon HSP70 expression was induced in all pH-treated groups though such induction was more in acid-stressed fish. HSP90 was found to increase only in acid-stressed carp brain. Expression of NFkB was elevated significantly at each treatment group except for pH 7.5. Finally, both acidic and alkaline pH in the aquatic system was found to disturb oxidative balance in carp brain which ultimately affects the neurological activity in carp. However, acidic environment in the aquatic system was more detrimental than the alkaline system regarding oxidative damage and subsequent neurotoxicity in carp brain.

The Molecular Chaperone Heat Shock Protein 70 Controls Liver Cancer Initiation and Progression by Regulating Adaptive DNA Damage and Mitogen-Activated Protein Kinase/Extracellular Signal-Regulated Kinase Signaling Pathways

Delineating the mechanisms that drive hepatic injury and hepatocellular carcinoma (HCC) progression is critical for development of novel treatments for recurrent and advanced HCC but also for the development of diagnostic and preventive strategies. Heat shock protein 70 (HSP70) acts in concert with several cochaperones and nucleotide exchange factors and plays an essential role in protein quality control that increases survival by protecting cells against environmental stressors. Specifically, the HSP70-mediated response has been implicated in the pathogenesis of cancer, but the specific mechanisms by which HSP70 may support malignant cell transformation remains to be fully elucidated. Here, we show that genetic ablation of HSP70 markedly impairs HCC initiation and progression by distinct but overlapping pathways. This includes the potentiation of the carcinogen-induced DNA damage response, at the tumor initiation stage, to increase the p53-dependent surveillance response leading to the cell cycle exit or death of genomically damaged differentiated pericentral hepatocytes, and this may also prevent their conversion into more proliferating HCC progenitor cells. Subsequently, activation of a mitogen-activated protein kinase/extracellular signal-regulated kinase (MAPK/ERK) negative feedback pathway diminishes oncogenic signals, thereby attenuating premalignant cell transformation and tumor progression. Modulation of HSP70 function may be a strategy for interfering with oncogenic signals driving liver cell transformation and tumor progression, thus providing an opportunity for human cancer control.

Mechanisms of insulin resistance by simvastatin in C2C12 myotubes and in mouse skeletal muscle

Statins inhibit cholesterol biosynthesis and lower serum LDL-cholesterol levels. They are generally well tolerated, but can cause insulin resistance in patients. Therefore, we investigated the mechanisms underlying the statin-induced insulin resistance. We used mice and C2C12 myotubes (murine cell line): mice (n = 10) were treated with oral simvastatin (5 mg/kg/day) or water (control) for 21 days and C2C12 cells were exposed to 10 μM simvastatin for 24 h. After intraperitoneal glucose application (2 g/kg), simvastatin-treated mice had higher glucose but equal insulin plasma concentrations than controls and lower glucose transport into skeletal muscle. Similarly, glucose uptake by C2C12 myotubes exposed to 10 μM simvastatin for 24 h was impaired compared to control cells. In simvastatin-treated C2C12 myotubes, mRNA and protein expression of the insulin receptor (IR) β-chain was increased, but the phosphorylation (Tyr1361) was impaired. Simvastatin decreased numerically Akt/PKB Thr308 phosphorylation (via insulin signaling pathway) and significantly Akt/PKB Ser473 phosphorylation (via mTORC2), which was explained by impaired phosphorylation of mTOR Ser2448. Reduced phosphorylation of Akt/PKB impaired downstream phosphorylation of GSK3β, leading to impaired translocation of GLUT4 into plasma membranes of C2C12 myotubes. In contrast, reduced phosphorylation of AS160 could be excluded as a reason for impaired GLUT4 translocation. In conclusion, simvastatin caused insulin resistance in mice and impaired glucose uptake in C2C12 myotubes. The findings in myotubes can be explained by diminished activation of Akt/PKB by mTORC2 and downstream effects on GSK3β, impairing the translocation of GLUT4 and the uptake of glucose.

The Hsp70 Gene Family in Boleophthalmus pectinirostris: Genome-Wide Identification and Expression Analysis under High Ammonia Stress

Simple Summary

Heat shock proteins 70 is a family of proteins, which were expressed in response to a wide range of biotic and abiotic stressors. The development of genomic resources and transcriptome sequences makes it practical to conduct a systematic analysis of these genes. In this study, exhaustive searches of all genomic resources for Boleophthalmus pectinirostris Hsp70 genes were performed and their responses to high environmental ammonia stress were investigated. Besides, selection test was implemented on those duplicated genes, and the phylogenetic tree, gene structure, and motif analysis were also constructed to assign names of them. The result showed that there were 20 Hsp70 genes within the genome of Boleophthalmus pectinirostris, and some sites in the duplicated genes may experience positive selection, and most of Hsp70 genes were downregulated after exposure to high concentration ammonia. The present results of this study can be used as a reference for further biological studies on mudskippers.

Abstract

Heat shock proteins 70 have triggered a remarkable large body of research in various fishes; however, no genome-wide identification and expression analysis has been performed on the Hsp70 gene family of Boleophthalmus pectinirostris. In this study, we identified 20 Hsp70 genes within the genome of B. pectinirostris and provided insights into their response to high environmental ammonia (HEA) stress. Positive selection on stress response genes and expansion of hspa1a and hspa1a-like genes might be related to terrestrial adaptations in this species. The expression patterns of the Hsp70 gene family in the gill and liver of B. pectinirostris under HEA stress were studied by examining transcriptome data. The results showed that most Hsp70 genes were downregulated after high concentration ammonia exposure. The downregulation may be related to the hypoxic condition of the tissues.

Melatonin ameliorates H2O2-induced oxidative stress through modulation of Erk/Akt/NFkB pathway

Background

Improper control on reactive oxygen species (ROS) elimination process and formation of free radicals causes tissue dysfunction. Pineal hormone melatonin is considered a potent regulator of such oxidative damage in different vertebrates. Aim of the current communication is to evaluate the levels of oxidative stress and ROS induced damage, and amelioration of oxidative status through melatonin induced activation of signaling pathways. Hepatocytes were isolated from adult Labeo rohita and exposed to H₂O₂ at three different doses (12.5, 25 and 50 µM) to observe peroxide induced damage in fish hepatocytes. Melatonin (25, 50 and 100 μg/ml) was administered against the highest dose of H₂O₂. Enzymatic and non-enzymatic antioxidants such as malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT) and glutathione (GSH) was measured spectrophotometrically. Expression level of heat shock proteins (HSP70 and HSP90), HSPs-associated signaling molecules (Akt, ERK, cytosolic and nuclear NFkB), and melatonin receptor was also measured by western blotting analysis.

Results

H₂O₂ induced oxidative stress significantly altered (P < 0.05) MDA and GSH level, SOD and CAT activity, and up regulated HSP70 and HSP90 expression in carp hepatocytes. Signaling proteins exhibited differential modulation as revealed from their expression patterns in H₂O₂-exposed fish hepatocytes, in comparison with control hepatocytes. Melatonin treatment of H₂O₂-stressed fish hepatocytes restored basal cellular oxidative status in a dose dependent manner. Melatonin was observed to be inducer of signaling process by modulation of signaling molecules and melatonin receptor.

Conclusions

The results suggest that exogenous melatonin at the concentration of 100 µg/ml is required to improve oxidative status of the H₂O₂-stressed fish hepatocytes. In H₂O₂ exposed hepatocytes, melatonin modulates expression of HSP70 and HSP90 that enable the hepatocytes to become stress tolerant and survive by altering the actions of ERK, Akt, cytosolic and nuclear NFkB in the signal transduction pathways. Study also confirms that melatonin could act through melatonin receptor coupled to ERK/Akt signaling pathways. This understanding of the mechanism by which melatonin regulates oxidative status in the stressed hepatocytes may initiate the development of novel strategies for hepatic disease therapy in future.

Targeted Deletion of Hsf1, 2, and 4 Genes in Mice

Heat shock transcription factors (Hsfs) regulate transcription of heat shock proteins as well as other genes whose promoters contain heat shock elements (HSEs). There are at least five Hsfs in mammalian cells, Hsf1, Hsf2, Hsf3, Hsf4, and Hsfy (Wu, Annu Rev Cell Dev Biol 11:441-469, 1995; Morimoto, Genes Dev 12:3788-3796, 1998; Tessari et al., Mol Hum Repord 4:253-258, 2004; Fujimoto et al., Mol Biol Cell 21:106-116, 2010; Nakai et al., Mol Cell Biol 17:469-481, 1997; Sarge et al., Genes Dev 5:1902-1911, 1991). To understand the physiological roles of Hsf1, Hsf2, and Hsf4 in vivo, we generated knockout mouse lines for these factors (Zhang et al., J Cell Biochem 86:376-393, 2002; Wang et al., Genesis 36:48-61, 2003; Min et al., Genesis 40:205-217, 2004). Numbers of other laboratories have also generated Hsf1 (Xiao et al., EMBO J 18:5943-5952, 1999; Sugahara et al., Hear Res 182:88-96, 2003), Hsf2 (McMillan et al., Mol Cell Biol 22:8005-8014, 2002; Kallio et al., EMBO J 21:2591-2601, 2002), and Hsf4 (Fujimoto et al., EMBO J 23:4297-4306, 2004) knockout mouse models. In this chapter, we describe the design of the targeting vectors, the plasmids used, and the successful generation of mice lacking the individual genes. We also briefly describe what we have learned about the physiological functions of these genes in vivo.

Early gestational maternal low-protein diet diminishes hepatic response to fasting in young adult male mice

Maternal low-protein (MLP) diet can lead to hepatic steatosis, which only develops with ageing. It is still unclear whether the young offspring show any signs of past exposure to prenatal adverse conditions. We hypothesized that early nutritional insult would first affect the dynamic responsiveness to nutritional challenges rather than the static state. We analyzed the transcriptome and metabolome profiles of the hepatic response to fasting/refeeding in young male mice offspring to identify changes induced by early gestational MLP diet. Restricted MLP exposure strictly to early gestation was achieved by the embryo transfer method. As a result, the fasting-induced upregulation of genes related to long-chain fatty acid metabolism and of stress response genes related to protein folding were significantly diminished in MLP pups. Lipid profiling after fasting showed that the hepatic signature of triacylglycerols was shifted to longer acyl-chains and higher saturation by the MLP diet. Bioinformatic analyses suggested that these phenomenological changes may be partially linked to the peroxisome proliferator activated receptor α (PPARα) pathway. Taken together, early gestational MLP diet affected the hepatic dynamic response to nutritional stress in seemingly healthy young offspring, accompanied with partial deterioration of PPARα action.

Injectable PLGA/Fe3O4 implants carrying cisplatin for synergistic magnetic hyperthermal ablation of rabbit VX2 tumor

Magnetic hyperthermia ablation has attracted wide attention in tumor therapy for its minimal invasion. Although the chemo-hyperthermal synergism has been proven to be effective in subcutaneously xenografted tumors of nude mice in our previous experiment, the occurrence of residual tumors due to incomplete ablation is more common in relatively larger and deeper-seated tumors in anti-tumor therapy. Thus, a larger tumor and larger animal model are needed for further study of the therapeutic efficacy. In this study, we tested the efficiency of this newly developed technique using a rabbit tumor model. Furthermore, we chose cisplatin (DDP), which has been confirmed with high efficiency in enhancing hyperthermia therapy as the chemotherapeutic drug for the synergistic magnetic hyperthermal ablation therapy of tumors. In vitro studies demonstrated that developed DDP-loaded magnetic implants (DDP/PLGA-Fe₃O₄) have great heating efficacy and the drug release can be significantly boosted by an external alternating magnetic field (AMF). In vivo studies showed that the phase-transitional DDP/PLGA-Fe₃O₄ materials that are ultrasound (US) and computerized tomography (CT) visible can be well confined in the tumor tissues after injection. When exposed to AMF, efficient hyperthermia was induced, which led to the cancer cells’ coagulative necrosis and accelerating release of the drug to kill residual tumors. Furthermore, an activated anti-tumor immune system can promote apoptosis of tumor cells. In conclusion, the DDP/PLGA-Fe₃O₄ implants can be used efficiently for the combined chemotherapy and magnetic-hyperthermia ablation of rabbit tumors.

Colony-stimulating factor 2 enhances the developmental competence of yak (Poephagus grunniens) preimplantation embryos by modulating the expression of heat shock protein 70 kDa 1A

Colony-stimulating factor 2 (CSF₂) is known to promote the development and survival of rodents and ruminants preimplantation embryos; however, the effect of CSF₂ on yak embryos has not been reported. The objective of this study was to investigate the effects of CSF₂ on the developmental competence of yak embryos cultured in vitro in modified synthetic oviduct fluid (mSOF) medium and on the expression pattern of heat shock protein 70 kDa 1A (HSPA1A). In each experiment, cumulus-oocyte complexes (COCs) were matured in vitro and fertilized with frozen-thawed semen. Zygotes were treated with varying concentrations of CSF₂ (0, 10, 50, 100 ng/mL) until day 8 after fertilization. Embryo development was calculated as the percentage of oocytes that formed embryos at the 2-cell, 4-cell, 8-cell, 16-cell, morula and blastocyst stages. The total cell numbers (TCN) per blastocyst and their allocation to the inner cell mass (ICM) and trophectoderm (TE) lineages were determined using differential CDX2 staining. The expression of HSPA1A was examined by quantitative real-time PCR (qRT-PCR) and immunochemistry to determine the mRNA and protein levels. The results showed that treatment with 50 ng/mL CSF₂ significantly (P < 0.05) increased the rate of blastocyst formation (19.01% versus 9.93%) and the TCN per blastocyst (96.94 versus 81.41) compared to the control group. However, no significant differences were observed in the other stages of development. qRT-PCR analysis confirmed that treatment with 50 ng/mL CSF₂ significantly (P < 0.05) inhibited the expression of HSPA1A mRNA in blastocysts cultured in vitro relative to the control group, but there were no significant differences between the other treatment groups. Immunocytochemical analysis confirmed that HSPA1A protein accumulation was gradually reduced in yak blastocysts cultured in 0, 10, 100 or 50 ng/mL CSF₂, however, no significant differences were observed between the 10 and 100 ng/mL treatments (P > 0.05). In conclusion, these findings demonstrate that CSF₂ inhibits the expression of HSPA1A to facilitate yak blastocyst formation and increase cell numbers.

The Role of Heat Shock Factors in Mammalian Spermatogenesis

Heat shock transcription factors (HSFs), as regulators of heat shock proteins (HSPs) expression, are well known for their cytoprotective functions during cellular stress. They also play important yet less recognized roles in gametogenesis. All HSF family members are expressed during mammalian spermatogenesis, mainly in spermatocytes and round spermatids which are characterized by extensive chromatin remodeling. Different HSFs could cooperate to maintain proper spermatogenesis. Cooperation of HSF1 and HSF2 is especially well established since their double knockout results in meiosis arrest, spermatocyte apoptosis, and male infertility. Both factors are also involved in the repackaging of the DNA during spermatid differentiation. They can form heterotrimers regulating the basal level of transcription of target genes. Moreover, HSF1/HSF2 interactions are lost in elevated temperatures which can impair the transcription of genes essential for spermatogenesis. In most mammals, spermatogenesis occurs a few degrees below the body temperature and spermatogenic cells are extremely heat-sensitive. Pro-survival pathways are not induced by heat stress (e.g., cryptorchidism) in meiotic and postmeiotic cells. Instead, male germ cells are actively eliminated by apoptosis, which prevents transition of the potentially damaged genetic material to the next generation. Such a response depends on the transcriptional activity of HSF1 which in contrary to most somatic cells, acts as a proapoptotic factor in spermatogenic cells. HSF1 activation could be the main trigger of impaired spermatogenesis related not only to elevated temperature but also to other stress conditions; therefore, HSF1 has been proposed to be the quality control factor in male germ cells.

Maternal obesity in mice not only affects fresh embryo quality but also aggravates injury due to vitrification

PURPOSE

The aims of the present study are to identify the mechanism(s) whereby obesity impairs fresh embryos and to clarify the effects of vitrification on lipid droplet content within embryos from maternally obese mice.

METHODS

The diet-induced obesity mouse model was established, and the zygotes were captured and cultured to day 3. The eight-cell embryos were selected and divided into fresh and vitrified groups. The blastocysts derived from fresh embryos were used as a control. The expression profiles of endoplasmic reticulum (ER) stress genes (Atf4, Grp78, and Hsp70) and other genes (MnSOD, p53, Gadd45g, caspase-3, IGF-II, ZO-1, and E-cadherin) on day-3 fresh and post-warming eight-cell embryos from obese and control groups were determined. For day-5 fresh blastocysts and blastocysts previously vitrified on day 3, the expression profiles for all of the above genes were also determined.

RESULTS

For the fresh group, obesity significantly upregulated Hsp70, p53, IGF-II, and ZO-1 expression in embryos on day 3 and notably upregulated Atf4, MnSOD, Gadd45g, caspase-3, ZO-1, and E-cadherin expression in blastocysts on day 5. For vitrified ones, obesity significantly upregulated Atf4, MnSOD, and Gadd45g expression in embryos on day 3 and notably upregulated Hsp70 expression and downregulated MnSOD in day 5 blastocysts previously vitrified on day 3.

CONCLUSIONS

Obesity impairs fresh embryos and aggravates embryonic vitrification injury at a molecular level.

Differential regulation of pro- and antiapoptotic proteins in fish adipocytes during hypoxic conditions

Worldwide, the frequencies and magnitudes of hypoxic events in estuarine waters have increased considerably over the past two decades. Fish populations are suitable indicators for the assessment of quality of aquatic ecosystems and often comprise a variety of adaptation systems by triggering oxidants, antioxidants and hypoxia-responsive signaling proteins. Signaling pathway may lead to cell survival or cell death which is fine-tuned by both positive and negative factors, which includes hypoxia-inducible factor-1α (HIF1α), heat-shock protein-70 (HSP70), phospho-c-Jun N-terminal kinase 1/2 (p-JNK1/2) and apoptosis signal-regulating kinase-1 (ASK1). In the present study, we attempt to determine stress-mediated signaling changes and molecular mechanism behind the cell survival by comparing adipocytes of fish from field hypoxic condition and laboratory-induced hypoxic condition (in vitro hypoxia). Comparison of field and laboratory studies in fish adipocytes showed differential expression of HIF1α, HSP70, p-JNK1/2 and ASK1 with altered oxidants and antioxidants. Further, the results also suggest that in vitro hypoxic conditions mimic field hypoxic conditions. Trends of hypoxia response were same in in vitro hypoxia of control adipocytes as in Ennore estuary, and hypoxia response was more pronounced in the test adipocytes under in vitro hypoxic condition. Results of the present work suggest that hypoxia is the major crusade of water pollutants affecting fish by differential regulation of pro- and antiapoptotic proteins probably through HSP70. This may play a vital role by providing cytoprotection in pollutant-induced stressed fish adipocytes substantiated by the in vitro hypoxic studies.

Thymosin β4 has a major role in dermal burn wound healing that involves actin cytoskeletal remodelling via heat-shock protein 70

Rapid vascular remodelling of damaged dermal tissue is required to heal burn wounds. Thymosin β4 (Tβ4) is a growth factor that has been shown to promote angiogenesis and dermal wound repair. However, the underlying mechanisms based on Tβ4 function have not yet been fully investigated. In the present study, we investigated how Tβ4 improves dermal burn wound healing via actin cytoskeletal remodelling and the action of heat-shock proteins (HSPs), which are a vital set of chaperone proteins that respond to heat shock. Our in vitro results achieved with the use of human umbilical vein endothelial cells (HUVECs) revealed a possible signal between Tβ4 and HSP70. Moreover, we confirmed that remodelling of filamentous actin (F-actin) was regulated by Tβ4-induced HSP70 in HUVECs. Based on these in vitro results, we confirmed the healing effects of Tβ4 in an adapted dermal burn wound in vivo model. Tβ4 improved wound-healing markers, such as wound closure and vascularization. Moreover, Tβ4 maintained the long-term expression of HSP70, which is associated with F-actin regulation during the wound-healing period. These results suggest that an association between Tβ4 and HSP70 is responsible for the healing of burn wounds, and that this association may regulate F-actin remodelling. Copyright © 2015 John Wiley & Sons, Ltd.

An artificial HSE promoter for efficient and selective detection of heat shock pathway activity

Detection of cellular stress is of major importance for the survival of cells. During evolution, a network of stress pathways developed, with the heat shock (HS) response playing a major role. The key transcription factor mediating HS signalling activity in mammalian cells is the HS factor HSF1. When activated it binds to the heat shock elements (HSE) in the promoters of target genes like heat shock protein (HSP) genes. They are induced by HSF1 but in addition they integrate multiple signals from different stress pathways. Here, we developed an artificial promoter consisting only of HSEs and therefore selectively reacting to HSF-mediated pathway activation. The promoter is highly inducible but has an extreme low basal level. Direct comparison with the HSPA1A promoter activity indicates that heat-dependent expression can be fully recapitulated by isolated HSEs in human cells. Using this sensitive reporter, we measured the HS response for different temperatures and exposure times. In particular, long heat induction times of 1 or 2 h were compared with short heat durations down to 1 min, conditions typical for burn injuries. We found similar responses to both long and short heat durations but at completely different temperatures. Exposure times of 2 h result in pathway activation at 41 to 44 °C, whereas heat pulses of 1 min lead to a maximum HS response between 47 and 50 °C. The results suggest that the HS response is initiated by a combination of temperature and exposure time but not by a certain threshold temperature.

LPS stimulates and Hsp70 down-regulates TLR4 to orchestrate differential cytokine response of culture-differentiated innate memory CD8(+) T cells

Nonconventional innate memory CD8(+) T cells characteristically expressing CD44, CD122, eomesodermin (Eomes) and promyelocytic leukemia zinc finger (PLZF) were derived in culture from CD4(+)CD8(+) double positive (DP) thymocytes of normal BALB/c and C57BL/6 mice. These culture-differentiated cells constitutively express toll-like receptor (TLR)4 and release interferon (IFN)-γ and interleukin (IL)-10. We show the TLR4-ligand lipopolysaccharide (LPS) stimulate the TLR and up-regulate IFN-γ skewing the cells towards type 1 polarization. In presence of LPS these cells also express suppressor of cytokine signaling (SOCS)1 and thus suppress IL-10 expression. In contrast, heat shock protein (Hsp)70 down-regulated TLR4 augmenting the anti-inflammatory cytokine IL-10. In association with IL-10 release IFN-γ was abrogated. The programmed cell death (PD)-1 mostly present in regulatory T cells was stimulated in these IL-10 producing cells by Hsp70 and not LPS indicating the cells can be driven to two contrast outcomes by the two TLR4 ligands. Our work provides a scope for in vitro monitoring of CD8(+) T cells to decipher important immune therapeutic option during infection or sepsis.

Therapeutic inducers of the HSP70/HSP110 protect mice against traumatic brain injury

Traumatic brain injury (TBI) induces severe harm and disability in many accident victims and combat-related activities. The heat-shock proteins Hsp70/Hsp110 protect cells against death and ischemic damage. In this study, we used mice deficient in Hsp110 or Hsp70 to examine their potential requirement following TBI. Data indicate that loss of Hsp110 or Hsp70 increases brain injury and death of neurons. One of the mechanisms underlying the increased cell death observed in the absence of Hsp110 and Hsp70 following TBI is the increased expression of reactive oxygen species-induced p53 target genes Pig1, Pig8, and Pig12. To examine whether drugs that increase the levels of Hsp70/Hsp110 can protect cells against TBI, we subjected mice to TBI and administered Celastrol or BGP-15. In contrast to Hsp110- or Hsp70i-deficient mice that were not protected following TBI and Celastrol treatment, there was a significant improvement of wild-type mice following administration of these drugs during the first week following TBI. In addition, assessment of neurological injury shows significant improvement in contextual and cued fear conditioning tests and beam balance in wild-type mice that were treated with Celastrol or BGP-15 following TBI compared to TBI-treated mice. These studies indicate a significant role of Hsp70/Hsp110 in neuronal survival following TBI and the beneficial effects of Hsp70/Hsp110 inducers toward reducing the pathological consequences of TBI. Our data indicate that loss of Hsp110 or Hsp70 in mice increases brain injury following TBI. (a) One of the mechanisms underlying the increased cell death observed in the absence of these Hsps following TBI is the increased expression of ROS-induced p53 target genes known as Pigs. In addition, (b) using drugs (Celastrol or BGP-15) to increase Hsp70/Hsp110 levels protect cells against TBI, suggesting the beneficial effects of Hsp70/Hsp110 inducers to reduce the pathological consequences of TBI.

An exploration of heat tolerance in mice utilizing mRNA and microRNA expression analysis

BACKGROUND

Individuals who rapidly develop hyperthermia during heat exposure (heat-intolerant) are vulnerable to heat associated illness and injury. We recently reported that heat intolerant mice exhibit complex alterations in stress proteins in response to heat exposure. In the present study, we further explored the role of genes and molecular networks associated with heat tolerance in mice.

METHODOLOGY

Heat-induced physiological and biochemical changes were assessed to determine heat tolerance levels in mice. We performed RNA and microRNA expression profiling on mouse gastrocnemius muscle tissue samples to determine novel biological pathways associated with heat tolerance.

PRINCIPAL FINDINGS

Mice (n = 18) were assigned to heat-tolerant (TOL) and heat-intolerant (INT) groups based on peak core temperatures during heat exposures. This was followed by biochemical assessments (Hsp40, Hsp72, Hsp90 and Hsf1 protein levels). Microarray analysis identified a total of 3,081 mRNA transcripts that were significantly misregulated in INT compared to TOL mice (p<0.05). Among them, Hspa1a, Dnajb1 and Hspb7 were differentially expressed by more than two-fold under these conditions. Furthermore, we identified 61 distinct microRNA (miRNA) sequences significantly associated with TOL compared to INT mice; eight miRNAs corresponded to target sites in seven genes identified as being associated with heat tolerance pathways (Hspa1a, Dnajb1, Dnajb4, Dnajb6, Hspa2, Hspb3 and Hspb7).

CONCLUSIONS

The combination of mRNA and miRNA data from the skeletal muscle of adult mice following heat stress provides new insights into the pathophysiology of thermoregulatory disturbances of heat intolerance.

Identification and characterization of a novel human methyltransferase modulating Hsp70 protein function through lysine methylation

Hsp70 proteins constitute an evolutionarily conserved protein family of ATP-dependent molecular chaperones involved in a wide range of biological processes. Mammalian Hsp70 proteins are subject to various post-translational modifications, including methylation, but for most of these, a functional role has not been attributed. In this study, we identified the methyltransferase METTL21A as the enzyme responsible for trimethylation of a conserved lysine residue found in several human Hsp70 (HSPA) proteins. This enzyme, denoted by us as HSPA lysine (K) methyltransferase (HSPA-KMT), was found to catalyze trimethylation of various Hsp70 family members both in vitro and in vivo, and the reaction was stimulated by ATP. Furthermore, we show that HSPA-KMT exclusively methylates 70-kDa proteins in mammalian protein extracts, demonstrating that it is a highly specific enzyme. Finally, we show that trimethylation of HSPA8 (Hsc70) has functional consequences, as it alters the affinity of the chaperone for both the monomeric and fibrillar forms of the Parkinson disease-associated protein α-synuclein.

A protective Hsp70-TLR4 pathway in lethal oxidant lung injury

Administering high levels of inspired oxygen, or hyperoxia, is commonly used as a life-sustaining measure in critically ill patients. However, prolonged exposures can exacerbate respiratory failure. Our previous study showed that TLR4 confers protection against hyperoxia-induced lung injury and mortality. Hsp70 has potent cytoprotective properties and has been described as a TLR4 ligand in cell lines. We sought to elucidate the relationship between TLR4 and Hsp70 in hyperoxia-induced lung injury in vitro and in vivo and to define the signaling mechanisms involved. Wild-type, TLR4(-/-), and Trif(-/-) (a TLR4 adapter protein) murine lung endothelial cells (MLECs) were exposed to hyperoxia. We found markedly elevated levels of intracellular and secreted Hsp70 from wild-type mice lungs and MLECs after hyperoxia. We confirmed that Hsp70 and TLR4 coimmunoprecipitate in lung tissue and MLECs. Hsp70-mediated NF-κB activation appears to depend upon TLR4. In the absence of TLR4, Hsp70 loses its protective effects in endothelial cells. Furthermore, these protective properties of Hsp70 are TLR4 adapter Trif dependent and MyD88 independent. Hsp70-deficient mice have increased mortality during hyperoxia, and lung-targeted adenoviral delivery of Hsp70 effectively rescues both Hsp70-deficient and wild-type mice. To our knowledge, our studies are the first to define an Hsp70-TLR4-Trif cytoprotective axis in the lung and endothelial cells. This pathway is a potential therapeutic target against a range of oxidant-induced lung injuries.

Double-effector nanoparticles: a synergistic approach to apoptotic hyperthermia

Highly efficient apoptotic hyperthermia is achieved using a double-effector nanoparticle that can generate reactive oxygen species (ROS) and heat. ROS render cancer cells more susceptible to subsequent heat treatment, which remarkably increases the degree of apoptotic cell death. Xenograft tumors (100 mm(3)) in mice are completely eliminated within 8 days after a single mild magnetic hyperthermia treatment at 43 °C for 30 min.

Effect of KCNJ5 mutations on gene expression in aldosterone-producing adenomas and adrenocortical cells

CONTEXT

Primary aldosteronism is a heterogeneous disease that includes both sporadic and familial forms. A point mutation in the KCNJ5 gene is responsible for familial hyperaldosteronism type III. Somatic mutations in KCNJ5 also occur in sporadic aldosterone producing adenomas (APA).

OBJECTIVE

The objective of the study was to define the effect of the KCNJ5 mutations on gene expression and aldosterone production using APA tissue and human adrenocortical cells.

METHODS

A microarray analysis was used to compare the transcriptome profiles of female-derived APA samples with and without KCNJ5 mutations and HAC15 adrenal cells overexpressing either mutated or wild-type KCNJ5. Real-time PCR validated a set of differentially expressed genes. Immunohistochemical staining localized the KCNJ5 expression in normal adrenals and APA.

RESULTS

We report a 38% (18 of 47) prevalence of KCNJ5 mutations in APA. KCNJ5 immunostaining was highest in the zona glomerulosa of NA and heterogeneous in APA tissue, and KCNJ5 mRNA was 4-fold higher in APA compared with normal adrenals (P < 0.05). APA with and without KCNJ5 mutations displayed slightly different gene expression patterns, notably the aldosterone synthase gene (CYP11B2) was more highly expressed in APA with KCNJ5 mutations. Overexpression of KCNJ5 mutations in HAC15 increased aldosterone production and altered expression of 36 genes by greater than 2.5-fold (P < 0.05). Real-time PCR confirmed increases in CYP11B2 and its transcriptional regulator, NR4A2.

CONCLUSIONS

KCNJ5 mutations are prevalent in APA, and our data suggest that these mutations increase expression of CYP11B2 and NR4A2, thus increasing aldosterone production.

Identification of candidate genes downstream of TLR4 signaling after ozone exposure in mice: a role for heat-shock protein 70

BACKGROUND

Toll-like receptor 4 (TLR4) is involved in ozone (O3)-induced pulmonary hyperpermeability and inflammation, although the downstream signaling events are unknown.

OBJECTIVES

The aims of our study were to determine the mechanism through which TLR4 modulates O3-induced pulmonary responses and to use transcriptomics to determine potential TLR4 effector molecules.

METHODS

C3H/HeJ (HeJ; Tlr4 mutant) and C3H/HeOuJ (OuJ; Tlr4 normal) mice were exposed continuously to 0.3 ppm O3 or filtered air for 6, 24, 48, or 72 hr. We assessed inflammation using bronchoalveolar lavage and molecular analysis by mRNA microarray, quantitative RT-PCR (real-time polymerase chain reaction), immunoblots, immunostaining, and ELISAs (enzyme-linked immunosorbent assays). B6-Hspa1a/Hspa1btm1Dix/NIEHS (Hsp70-/-) and C57BL/6 (B6; Hsp70+/+ wild-type control) mice were used for candidate gene validation studies.

RESULTS

O3-induced TLR4 signaling occurred through myeloid differentiation protein 88 (MyD88)-dependent and -independent pathways in OuJ mice and involved multiple downstream pathways. Genomewide transcript analyses of lungs from air- and O3-exposed HeJ and OuJ mice identified a cluster of genes that were significantly up-regulated in O3-exposed OuJ mice compared with O3-exposed HeJ mice or air-exposed controls of both strains; this cluster included genes for heat-shock proteins (e.g., Hspa1b, Hsp70). Moreover, O3-induced inflammation, MyD88 up-regulation, extracellular-signal-related kinase-1/2 (ERK1/2) and activator protein-1 (AP-1) activation, and kerotinocyte-derived chemokine (KC) protein content were significantly reduced in Hspa1a/Hspa1btm1Dix (Hsp70-/-) compared with Hsp70+/+ mice (p < 0.05).

CONCLUSIONS

These studies suggest that HSP70 is an effector molecule downstream of TLR4 and is involved in the regulation of O3-induced lung inflammation by triggering similar pathways to TLR4. These novel findings may have therapeutic and preventive implications for inflammatory diseases resulting from environmental exposures.

Multiple hsp70 isoforms in the eukaryotic cytosol: mere redundancy or functional specificity?

Hsp70 molecular chaperones play a variety of functions in every organism, cell type and organelle, and their activities have been implicated in a number of human pathologies, ranging from cancer to neurodegenerative diseases. The functions, regulations and structure of Hsp70s were intensively studied for about three decades, yet much still remains to be learned about these essential folding enzymes. Genome sequencing efforts revealed that most genomes contain multiple members of the Hsp70 family, some of which co-exist in the same cellular compartment. For example, the human cytosol and nucleus contain six highly homologous Hsp70 proteins while the yeast Saccharomyces cerevisiae contains four canonical Hsp70s and three fungal-specific ribosome-associated and specialized Hsp70s. The reasons and significance of the requirement for multiple Hsp70s is still a subject of debate. It has been postulated for a long time that these Hsp70 isoforms are functionally redundant and differ only by their spatio-temporal expression patterns. However, several studies in yeast and higher eukaryotic organisms challenged this widely accepted idea by demonstrating functional specificity among Hsp70 isoforms. Another element of complexity is brought about by specific cofactors, such as Hsp40s or nucleotide exchange factors that modulate the activity of Hsp70s and their binding to client proteins. Hence, a dynamic network of chaperone/co-chaperone interactions has evolved in each organism to efficiently take advantage of the multiple cellular roles Hsp70s can play. We summarize here our current knowledge of the functions and regulations of these molecular chaperones, and shed light on the known functional specificities among isoforms.

Cellular thermotolerance is associated with heat shock protein 70.1 genetic polymorphisms in Holstein lactating cows

Heat shock proteins (Hsp) are known to protect cells from several stressors. Nucleotide changes in the flanking regions [5'- and 3'-untranslated region (UTR)] of Hsp gene might affect inducibility, degree of expression, or stability of Hsp70 mRNA. The present study aimed to investigate the association between inducible Hsp70.1 single nucleotide polymorphisms (SNPs) and heat shock (HS) response of peripheral blood mononuclear cells (PBMC) in dairy cows. Four hundred forty-six Italian Holstein cows were genotyped for four Hsp70.1 SNPs: g895 C/- and g1128 G/T in 5'-UTR, and g2154 G/A and g64 G/T in 3'-UTR. Genetic polymorphisms in 3'-UTR of bovine Hsp70.1 gene resulted monomorphic. Distribution of alleles of the nucleotide sequence polymorphism within the 5'-UTR of the bovine Hsp70.1 gene were 81.2% and 18.8% for C and -, respectively, and 77.8% and 22.2% for G and T, respectively. Among the 446 genotyped animals, a group of cows balanced for days in milk and parity was selected to be representative of the following genotypes: CC (n = 8), C- (n = 7), and -- (n = 7) and GG (n = 8), GT (n = 11), and TT (n = 3) in 5'-UTR. PBMC were isolated from blood samples and heated at 43°C in thermal bath for 1 h and then incubated at 39°C in atmosphere of 5% CO(2) for 1, 2, 4, 8, 16, and 24 h (recovery times). Cell viability was determined by XTT assay. Gene and protein expression of Hsp70.1 was determined by real-time reverse transcription-polymerase chain reaction and by ELISA assay, respectively. For the two SNPs detected, one allele was the most frequent (C, 66.8% and G, 56.8%). Genotypes -- and TG showed higher (P < 0.05) viability compared with CC and GG, respectively. Genotypes C- and TT had intermediate viability. Gene expression of Hsp70.1 showed higher (P < 0.001) levels in -- and TG genotype compared with their counterparts. Genotypes -- and TG showed the higher level of inducible Hsp70.1 protein in respect to C-, TT and CC, GG. In conclusion, exposure to HS differently affected cell viability and gene and protein expression of Hsp70.1 in the selected genotypes. These results indicate that the presence of SNPs (C/- and G/T) in the 5'-UTR region of inducible Hsp70.1 ameliorates HS response and tolerance to heat of bovine PBMC. These mutation sites may be useful as molecular genetic markers to assist selection for heat tolerance.

Microarray analysis of cellular thermotolerance

BACKGROUND AND OBJECTIVES

Previously, we have shown that a 43°C pretreatment can provide thermotolerance to a following, more severe, thermal stress at 45°C. Using cells that lack the Hsp70 gene, we have also shown that there is still some thermotolerance in the absence of HSP70 protein. The purpose of this study was to determine which genes play a role in thermotolerance by measuring viability and proliferation of the cells at 2 days after heating. Specifically, we wanted to understand which pathways may be responsible for protecting cells in the absence of HSP70.

STUDY DESIGN/MATERIALS AND METHODS

Murine embryonic fibroblast cells with and without Hsp70 (MEF(+/+) and MEF(-/-), respectively) were exposed to a mild heat shock of 43°C for 30 minutes in a constant temperature water bath. After 3 hours of recovery, RNA was harvested from three heated samples alongside three untreated controls using a MicroRNeasy kit with DNAse treatment. RNA quality was verified by an Agilent Bioanalyzer. The RNA was then converted to cDNA and hybridized to Affymetrix gene expression DNA microarrays. The genes that showed a twofold change (up or down) relative to unheated controls were filtered by t-test for significance at a threshold of P < 0.05 using Genespring software. Data were verified by qRT-PCR. Genes were then categorized based upon their ontology.

RESULTS

While many genes were similarly upregulated, the main difference between cell types was an increase in transcription factors and nucleic acid binding proteins. Several genes known to be involved in the heat response were upregulated more than twofold (Hsp70, Hsp40, Hsp110, Hsp25, Atf3), however, another well studied heat responsive gene Hsp90 only increased by 1.5-fold under these conditions despite its role in thermotolerance.

CONCLUSIONS

The data herein presents genetic pathways which are candidates for further study of pretreatment protocols in laser irradiation.

Differential expression of HSPA1 and HSPA2 proteins in human tissues; tissue microarray-based immunohistochemical study

In the present study we determined the expression pattern of HSPA1 and HSPA2 proteins in various normal human tissues by tissue-microarray based immunohistochemical analysis. Both proteins belong to the HSPA (HSP70) family of heat shock proteins. The HSPA2 is encoded by the gene originally defined as testis-specific, while HSPA1 is encoded by the stress-inducible genes (HSPA1A and HSPA1B). Our study revealed that both proteins are expressed only in some tissues from the 24 ones examined. HSPA2 was detected in adrenal gland, bronchus, cerebellum, cerebrum, colon, esophagus, kidney, skin, small intestine, stomach and testis, but not in adipose tissue, bladder, breast, cardiac muscle, diaphragm, liver, lung, lymph node, pancreas, prostate, skeletal muscle, spleen, thyroid. Expression of HSPA1 was detected in adrenal gland, bladder, breast, bronchus, cardiac muscle, esophagus, kidney, prostate, skin, but not in other tissues examined. Moreover, HSPA2 and HSPA1 proteins were found to be expressed in a cell-type-specific manner. The most pronounced cell-type expression pattern was found for HSPA2 protein. In the case of stratified squamous epithelia of the skin and esophagus, as well as in ciliated pseudostratified columnar epithelium lining respiratory tract, the HSPA2 positive cells were located in the basal layer. In the colon, small intestine and bronchus epithelia HSPA2 was detected in goblet cells. In adrenal gland cortex HSPA2 expression was limited to cells of zona reticularis. The presented results clearly show that certain human tissues constitutively express varying levels of HSPA1 and HSPA2 proteins in a highly differentiated way. Thus, our study can help designing experimental models suitable for cell- and tissue-type-specific functional differences between HSPA2 and HSPA1 proteins in human tissues.

Oocyte-targeted deletion reveals that hsp90b1 is needed for the completion of first mitosis in mouse zygotes

Background

Hsp90b1 is an endoplasmic reticulum (ER) chaperone (also named Grp94, ERp99, gp96,Targ2, Tra-1, Tra1, Hspc4) (MGI:98817) contributing with Hspa5 (also named Grp78, BIP) (MGI:95835) to protein folding in ER compartment. Besides its high protein expression in mouse oocytes, little is known about Hsp90b1 during the transition from oocyte-to-embryo. Because the constitutive knockout of Hsp90b1 is responsible for peri-implantation embryonic lethality, it was not yet known whether Hsp90b1 is a functionally important maternal factor.

Methodology/Findings

To circumvent embryonic lethality, we established an oocyte-specific conditional knockout line taking advantage of the more recently created floxed Hsp90b1 line (Hsp90b1^flox, MGI:3700023) in combination with the transgenic mouse line expressing the cre recombinase under the control of zona pellucida 3 (ZP3) promoter (Zp3-cre, MGI:2176187). Altered expression of Hsp90b1 in growing oocytes provoked a limited, albeit significant reduction of the zona pellucida thickness but no obvious anomalies in follicular growth, meiotic maturation or fertilization. Interestingly, mutant zygotes obtained from oocytes lacking Hsp90b1 were unable to reach the 2-cell stage. They exhibited either a G2/M block or, more frequently an abnormal mitotic spindle leading to developmental arrest. Despite the fact that Hspa5 displayed a similar profile of expression as Hsp90b1, we found that HSPA5 and HSP90B1 did not fully colocalize in zygotes suggesting distinct function for the two chaperones. Consequently, even if HSPA5 was overexpressed in Hsp90b1 mutant embryos, it did not compensate for HSP90B1 deficiency. Finally, further characterization of ER compartment and cytoskeleton revealed a defective organization of the cytoplasmic region surrounding the mutant zygotic spindle.

Conclusions

Our findings demonstrate that the maternal contribution of Hsp90b1 is critical for the development of murine zygotes. All together our data indicate that Hsp90b1 is involved in unique and specific aspects of the first mitosis, which brings together the maternal and paternal genomes on a single spindle.