The human heat-shock genes HSPA6 and HSPA7 are both expressed and localize to chromosome 1

YBX2 modulates mRNA stability via interaction with YTHDF2 in endometrial cancer cells

RNA-binding proteins (RBPs) fine-tune gene expression by modulating RNA stability, translation, and degradation. RBPs are involved in the development of endometrial cancer. In particular, Y-box binding protein 2 (YBX2), a germ cell-specific member of the YBX family, has been reported to maintain cancer stem cell-like phenotypes in endometrial cancer. However, the mechanism by which YBX2 modulates mRNA stability in endometrial cancer cells remains unknown. In this study, we examined the effects of the ectopic expression of YBX2 in endometrial adenocarcinoma-derived Ishikawa cells. We found that elevated levels of YBX2 delayed cell proliferation, without increasing cell apoptosis. Transcriptomic analysis revealed disturbances in gene expression caused by YBX2. Interestingly, heat shock protein family A (Hsp70) member 6 (HSPA6) levels were downregulated due to the reduced mRNA stability after YBX2 binding. YBX2 facilitated the formation of relatively stable cytoplasmic granules in tumor cells via its mRNA-binding domain. Moreover, N⁶-methyladenosine (m⁶A) reader proteins are recruited by YBX2 granules via the cold-shock domains. Notably, knockdown of YTH N⁶-methyladenosine RNA-binding protein F2 (YTHDF2), an m⁶A reader, ameliorated the reduction in HSPA6 mRNA levels induced by YBX2, indicating the synergistic effects of YBX2 and YTHDF2 on mRNA stability. Therefore, YBX2 regulates RNA stability by interacting with the m⁶A reader proteins.

HSPA6, a novel prognostic and therapeutic biomarker, associated with Ming classification in gastric cancer

OBJECTIVE

This study aimed to explore the clinical relevance of heat shock protein family A member 6 (HSPA6) in gastric cancer (GC) and its effect on GC cell proliferation.

METHODS

HSPA6 mRNA and protein levels were analyzed by bioinformatics, RT-qPCR, western blot and immunohistochemistry. HSPA6 was correlated with clinicopathological variables by the Chi-square test. Kaplan-Meier survival analysis and the univariate and multivariate Cox models were used to assess the prognostic value of HSPA6. Nomogram was used to predict overall survival in patients with GC. Knockdown or over-expression of HSPA6 in GC cell lines was constructed by lentiviral transduction. EdU and CCK-8 assay were used to detect cell proliferation. In vivo mouse tumor models were performed to evaluate the effects of HSPA6 on GC growth.

RESULTS

HSPA6 were significantly upregulated in the GC tissues compared to the normal stomach epithelium and were associated with Ming classification (p < 0.001) and tumor size (p = 0.002). Patients with high expression of HSPA6 showed worse survival compared to the low expression group. HSPA6 was identified to be an independent prognostic biomarker for GC. HSPA6 was functionally annotated with the cell cycle, G2M checkpoint and Hippo pathway. Knockdown of HSPA6 suppressed XGC-1 cell proliferation both in vitro and in vivo. Overexpression of HSPA6 in AGS cells increased proliferation rates, increased the levels of cyclinB1 and YAP and decreased that of phosphorylated YAP. HSPA6 knockdown in the NUGC2 cells had the opposite effect.

CONCLUSIONS

HSPA6 promotes GC proliferation by the Hippo pathway, as a novel prognostic biomarker and potential therapeutic target.

Targeted Analysis of HSP70 Isoforms in Human Spermatozoa in the Context of Capacitation and Motility

HSP70s constitute a family of chaperones, some isoforms of which appear to play a role in sperm function. Notably, global proteomic studies analyzing proteins deregulated in asthenozoospermia, a main cause of male infertility characterized by low sperm motility, showed the dysregulation of some HSP70 isoforms. However, to date, no clear trend has been established since the variations in the abundance of HSP70 isoforms differed between studies. The HSPA2 isoform has been reported to play a key role in fertilization, but its dysregulation and possible relocation during capacitation, a maturation process making the spermatozoon capable of fertilizing an oocyte, is debated in the literature. The aim of the present study was to investigate the fate of all sperm HSP70 isoforms during capacitation and in relation to sperm motility. Using Multiple-Reaction Monitoring (MRM) mass spectrometry, we showed that the relative abundance of all detected isoforms was stable between non-capacitated and capacitated spermatozoa. Immunofluorescence using two different antibodies also demonstrated the stability of HSP70 isoform localization during capacitation. We also investigated spermatozoa purified from 20 sperm samples displaying various levels of total and progressive sperm motility. We showed that the abundance of HSP70 isoforms is not correlated to sperm total or progressive motility.

Increased systemic HSP70B levels in spinal muscular atrophy infants

Despite newly available treatments for spinal muscular atrophy (SMA), novel circulating biomarkers are still critically necessary to track SMA progression and therapeutic response. To identify potential biomarkers, we performed whole‐blood RNA sequencing analysis in SMA type 1 subjects under 1 year old and age‐matched healthy controls. Our analysis revealed the Heat Shock Protein Family A Member 7 (HSPA7)/heat shock 70kDa protein 7 (HSP70B) as a novel candidate biomarker to track SMA progression early in life. Changes in circulating HSP70B protein levels were associated with changes in circulating neurofilament levels in SMA newborns and infants. Future studies will determine whether HSP70B levels respond to molecular therapies.

Prognostic Significance of the Hsp70 Gene Family in Colorectal Cancer

Background

Colorectal cancer (CRC) is a deadly form of cancer worldwide. Heat shock protein 70 (Hsp70) belongs to the family of human HSPs and plays an essential role in multiple cellular developments and in responding to environmental changes. However, studies on the relationship between CRC and the Hsp70 family are rare.

Material/Methods

Data pertaining to 438 patients with CRC was downloaded from The Cancer Genome Atlas database. To investigate the prognostic significance of the Hsp70 genes, survival and joint-effect analyses were conducted. The correlation between prognosis-related Hsp70 genes and clinical factors in CRC was analyzed using a nomogram. Gene set enrichment analysis (GSEA) was performed to explore the complex enrichment pathway in CRC with the prognosis-related Hsp70 genes.

Results

According to multivariate Cox regression survival analysis, low expression levels of HSPA1A, HSPA1B, and HSPA1L were correlated with improved overall survival (OS). According to the joint-effects survival analysis, the joint low expression levels of HSPA1A, HSPA1B, and HSPA1L were related to improved OS. The 1-, 3-, 5-, and 10-year survival rates of patients with CRC were predicted by constructing a nomogram model based on HSPA1A, HSPA1B, HSPA1L, and tumor stage. The GSEA results indicated the biological roles of HSPA1A, HSPA1B, and HSPA1L in CRC.

Conclusions

Low expression levels of HSPA1A, HSPA1B, and HSPA1L were strongly correlated with improved prognosis in CRC and might serve as latent prognostic biomarkers in CRC.

Effective control of tumor growth through spatial and temporal control of theranostic sodium iodide symporter (NIS) gene expression using a heat-inducible gene promoter in engineered mesenchymal stem cells

Purpose: The tumor homing characteristics of mesenchymal stem cells (MSCs) make them attractive vehicles for the tumor-specific delivery of therapeutic agents, such as the sodium iodide symporter (NIS). NIS is a theranostic protein that allows non-invasive monitoring of the in vivo biodistribution of functional NIS expression by radioiodine imaging as well as the therapeutic application of ¹³¹I. To gain local and temporal control of transgene expression, and thereby improve tumor selectivity, we engineered MSCs to express the NIS gene under control of a heat-inducible HSP70B promoter (HSP70B-NIS-MSCs).

Experimental Design: NIS induction in heat-treated HSP70B-NIS-MSCs was verified by ¹²⁵I uptake assay, RT-PCR, Western blot and immunofluorescence staining. HSP70B-NIS-MSCs were then injected i.v. into mice carrying subcutaneous hepatocellular carcinoma HuH7 xenografts, and hyperthermia (1 h at 41°C) was locally applied to the tumor. 0 - 72 h later radioiodine uptake was assessed by ¹²³I-scintigraphy. The most effective uptake regime was then selected for ¹³¹I therapy.

Results: The HSP70B promoter showed low basal activity in vitro and was significantly induced in response to heat. In vivo, the highest tumoral iodine accumulation was seen 12 h after application of hyperthermia. HSP70B-NIS-MSC-mediated ¹³¹I therapy combined with hyperthermia resulted in a significantly reduced tumor growth with prolonged survival as compared to control groups.

Conclusions: The heat-inducible HSP70B promoter allows hyperthermia-induced spatial and temporal control of MSC-mediated theranostic NIS gene radiotherapy with efficient tumor-selective and temperature-dependent accumulation of radioiodine in heat-treated tumors.

HSPA6: A new autosomal recessive candidate gene for the VATER/VACTERL malformation spectrum

BACKGROUND

The VATER/VACTERL association refers to the nonrandom co-occurrence of at least three of the following component features (CFs): vertebral defects (V), anorectal malformations (ARM) (A), cardiac defects (C), tracheoesophageal fistula with or without esophageal atresia (TE), renal malformations (R), and limb defects (L). Patients presenting with two CFs have been termed VATER/VACTERL-like phenotypes.

METHODS

We surveyed the exome for recessive disease variants in three affected sib-pairs. Sib-pair 971 consisted of two brothers with ARM and additional hydronephrosis in one brother. Sib-pair 1098 consisted of two sisters with ARM. In family 1346, the daughter presented with ARM and additional hypoplasia of both small fingers and ankyloses. Her brother presented with unilateral isolated radial hypoplasia. Sib-pairs 971 and 1346 resembled a VATER/VACTERL-like phenotype.

RESULTS

We detected a novel maternally inherited missense variant (c.1340G > T) and a rare paternally inherited deletion of the trans-allele in HSPA6 in both siblings of family 1346. HSPA6 belongs to the heat shock protein (HSP) 70 family. Re-sequencing of HSPA6 in 167 patients with VATER/VACTERL and VATER/VACTERL-like phenotypes did not reveal any additional bi-allelic variants.

CONCLUSIONS

Until now, only TNF-receptor associated protein 1 (TRAP1) had been reported as an autosomal recessive disease-gene for the VATER/VACTERL association. TRAP1 belongs to the heat shock protein 90 family (HSP90). Both Hsp70 and Hsp90 genes have been shown to be important embryonic drivers in the formation of mouse embryonic forelimb tissue. Our results suggest HSPA6 as a new candidate gene in VATER/VACTERL-like phenotypes.

Olive Oil and the Hallmarks of Aging

Aging is a multifactorial and tissue-specific process involving diverse alterations regarded as the "hallmarks of aging", which include genomic instability, telomere attrition, epigenetic alterations, loss of proteostasis, deregulated nutrient sensing, mitochondrial dysfunction, cellular senescence, stem cell exhaustion and altered intracellular communication. Virtually all these hallmarks are targeted by dietary olive oil, particularly by virgin olive oil, since many of its beneficial effects can be accounted not only for the monounsaturated nature of its predominant fatty acid (oleic acid), but also for the bioactivity of its minor compounds, which can act on cells though both direct and indirect mechanisms due to their ability to modulate gene expression. Among the minor constituents of virgin olive oil, secoiridoids stand out for their capacity to modulate many pathways that are relevant for the aging process. Attenuation of aging-related alterations by olive oil or its minor compounds has been observed in cellular, animal and human models. How olive oil targets the hallmarks of aging could explain the improvement of health, reduced risk of aging-associated diseases, and increased longevity which have been associated with consumption of a typical Mediterranean diet containing this edible oil as the predominant fat source.

Xenohormetic and anti-aging activity of secoiridoid polyphenols present in extra virgin olive oil: a new family of gerosuppressant agents

Aging can be viewed as a quasi-programmed phenomenon driven by the overactivation of the nutrient-sensing mTOR gerogene. mTOR-driven aging can be triggered or accelerated by a decline or loss of responsiveness to activation of the energy-sensing protein AMPK, a critical gerosuppressor of mTOR. The occurrence of age-related diseases, therefore, reflects the synergistic interaction between our evolutionary path to sedentarism, which chronically increases a number of mTOR activating gero-promoters (e.g., food, growth factors, cytokines and insulin) and the "defective design" of central metabolic integrators such as mTOR and AMPK. Our laboratories at the Bioactive Food Component Platform in Spain have initiated a systematic approach to molecularly elucidate and clinically explore whether the "xenohormesis hypothesis," which states that stress-induced synthesis of plant polyphenols and many other phytochemicals provides an environmental chemical signature that upregulates stress-resistance pathways in plant consumers, can be explained in terms of the reactivity of the AMPK/mTOR-axis to so-called xenohormetins. Here, we explore the AMPK/mTOR-xenohormetic nature of complex polyphenols naturally present in extra virgin olive oil (EVOO), a pivotal component of the Mediterranean style diet that has been repeatedly associated with a reduction in age-related morbid conditions and longer life expectancy. Using crude EVOO phenolic extracts highly enriched in the secoiridoids oleuropein aglycon and decarboxymethyl oleuropein aglycon, we show for the first time that (1) the anticancer activity of EVOO secoiridoids is related to the activation of anti-aging/cellular stress-like gene signatures, including endoplasmic reticulum (ER) stress and the unfolded protein response, spermidine and polyamine metabolism, sirtuin-1 (SIRT1) and NRF2 signaling; (2) EVOO secoiridoids activate AMPK and suppress crucial genes involved in the Warburg effect and the self-renewal capacity of "immortal" cancer stem cells; (3) EVOO secoiridoids prevent age-related changes in the cell size, morphological heterogeneity, arrayed cell arrangement and senescence-associated β-galactosidase staining of normal diploid human fibroblasts at the end of their proliferative lifespans. EVOO secoiridoids, which provide an effective defense against plant attack by herbivores and pathogens, are bona fide xenohormetins that are able to activate the gerosuppressor AMPK and trigger numerous resveratrol-like anti-aging transcriptomic signatures. As such, EVOO secoiridoids constitute a new family of plant-produced gerosuppressant agents that molecularly "repair" the aimless (and harmful) AMPK/mTOR-driven quasi-program that leads to aging and aging-related diseases, including cancer.

Quantitative analyses of postmortem heat shock protein mRNA profiles in the occipital lobes of human cerebral cortices: implications in cause of death

Quantitative RNA analyses of autopsy materials to diagnose the cause and mechanism of death are challenging tasks in the field of forensic molecular pathology. Alterations in mRNA profiles can be induced by cellular stress responses during supravital reactions as well as by lethal insults at the time of death. Here, we demonstrate that several gene transcripts encoding heat shock proteins (HSPs), a gene family primarily responsible for cellular stress responses, can be differentially expressed in the occipital region of postmortem human cerebral cortices with regard to the cause of death. HSPA2 mRNA levels were higher in subjects who died due to mechanical asphyxiation (ASP), compared with those who died by traumatic injury (TI). By contrast, HSPA7 and A13 gene transcripts were much higher in the TI group than in the ASP and sudden cardiac death (SCD) groups. More importantly, relative abundances between such HSP mRNA species exhibit a stronger correlation to, and thus provide more discriminative information on, the death process than does routine normalization to a housekeeping gene. Therefore, the present study proposes alterations in HSP mRNA composition in the occipital lobe as potential forensic biological markers, which may implicate the cause and process of death.

Measuring intracellular hsp70 in leukocytes by flow cytometry

Heat shock or stress proteins are constitutively expressed redox-sensitive proteins, the synthesis of which is induced in almost all organisms exposed to a range of stressors, including heat shock, oxidative stress, free radicals, UV radiation, and heavy metals. This unit details a method, with supporting protocols, for the measurement of their expression in peripheral blood leukocytes by flow cytometry.

Molecular cloning and characterization of cDNA encoding a putative stress-induced heat-shock protein from Camelus dromedarius

Heat shock proteins are ubiquitous, induced under a number of environmental and metabolic stresses, with highly conserved DNA sequences among mammalian species. Camelus dromedaries (the Arabian camel) domesticated under semi-desert environments, is well adapted to tolerate and survive against severe drought and high temperatures for extended periods. This is the first report of molecular cloning and characterization of full length cDNA of encoding a putative stress-induced heat shock HSPA6 protein (also called HSP70B′) from Arabian camel. A full-length cDNA (2417 bp) was obtained by rapid amplification of cDNA ends (RACE) and cloned in pET-b expression vector. The sequence analysis of HSPA6 gene showed 1932 bp-long open reading frame encoding 643 amino acids. The complete cDNA sequence of the Arabian camel HSPA6 gene was submitted to NCBI GeneBank (accession number HQ214118.1). The BLAST analysis indicated that C. dromedaries HSPA6 gene nucleotides shared high similarity (77–91%) with heat shock gene nucleotide of other mammals. The deduced 643 amino acid sequences (accession number ADO12067.1) showed that the predicted protein has an estimated molecular weight of 70.5 kDa with a predicted isoelectric point (pI) of 6.0. The comparative analyses of camel HSPA6 protein sequences with other mammalian heat shock proteins (HSPs) showed high identity (80–94%). Predicted camel HSPA6 protein structure using Protein 3D structural analysis high similarities with human and mouse HSPs. Taken together, this study indicates that the cDNA sequences of HSPA6 gene and its amino acid and protein structure from the Arabian camel are highly conserved and have similarities with other mammalian species.

Chemo-resistant protein expression pattern of glioblastoma cells (A172) to perillyl alcohol

Glioblastoma multiform (GBM) is by far the most malignant glioma. We have introduced a new treatment for GBMs that comprises the inhalation of a naturally occurring terpene with chemotherapeutic properties known as perillyl alcohol (POH). Clinical trial results on recurrent GBM patients showed that POH extends the average life by more than eight months, temporarily slows tumor growth, and in some cases even decreases tumor size. After approximately seven months, the tumor continues to grow and leads to a dismal prognosis. To investigate how these tumors become resistant to POH, we generated an A172 human glioblastoma cell culture tolerant to 0.06 mM of POH (A172r). We used Multidimensional Protein Identification Technology (MudPIT) to compare the protein expression profile of A172r cells to the established glioblastoma A172 cell line. Our results include a list of identified proteins unique to either the resistant or the nonresistant cell line. These proteins are related to cellular growth, negative apoptosis regulation, Ras pathway, and other key cellular functions that could be connected to the underlying mechanisms of resistance.

Crystal structures of the ATPase domains of four human Hsp70 isoforms: HSPA1L/Hsp70-hom, HSPA2/Hsp70-2, HSPA6/Hsp70B', and HSPA5/BiP/GRP78

The 70-kDa heat shock proteins (Hsp70) are chaperones with central roles in processes that involve polypeptide remodeling events. Hsp70 proteins consist of two major functional domains: an N-terminal nucleotide binding domain (NBD) with ATPase activity, and a C-terminal substrate binding domain (SBD). We present the first crystal structures of four human Hsp70 isoforms, those of the NBDs of HSPA1L, HSPA2, HSPA5 and HSPA6. As previously with Hsp70 family members, all four proteins crystallized in a closed cleft conformation, although a slight cleft opening through rotation of subdomain IIB was observed for the HSPA5-ADP complex. The structures presented here support the view that the NBDs of human Hsp70 function by conserved mechanisms and contribute little to isoform specificity, which instead is brought about by the SBDs and by accessory proteins.

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HSP70s: From Tumor Transformation to Cancer Therapy

Heat shock proteins (HSPs) are a defined set of chaperones for maintaining proper functions of proteins. The HSP70 family, one of the most inducible families in response to stress, protects cells from stress-induced cell death. It has been documented that HSP70s are highly expressed in various types of cancer cells and make the cells resistant to adverse microenvironments, such as hypoxia and glucose starvation, which are common features in malignant progression. Over-expression of HSP70s is thus associated with tumor transformation and eventually results in a decrease of chemotherapy efficacy. Notably, the distribution of HSP70s is deregulated in cancer cells. It has been reported that HSP70s localize distinct organelles or are exported to humoral circulation during cancer development. Either surface or exported HSP70s play danger signals and trigger immune response to destroy the tumor cells. In this review, we lay out recent advances in the HSP70s-mediated cancer diagnosis and therapy. This review would be enlightening for clinical cancer medicine.

hsp70 genes in the human genome: Conservation and differentiation patterns predict a wide array of overlapping and specialized functions

Background

Hsp70 chaperones are required for key cellular processes and response to environmental changes and survival but they have not been fully characterized yet. The human hsp70-gene family has an unknown number of members (eleven counted over ten years ago); some have been described but the information is incomplete and inconsistent. A coherent body of knowledge encompassing all family components that would facilitate their study individually and as a group is lacking. Nowadays, the study of chaperone genes benefits from the availability of genome sequences and a new protocol, chaperonomics, which we applied to elucidate the human hsp70 family.

Results

We identified 47 hsp70 sequences, 17 genes and 30 pseudogenes. The genes distributed into seven evolutionarily distinct groups with distinguishable subgroups according to phylogenetic and other data, such as exon-intron and protein features. The N-terminal ATP-binding domain (ABD) was conserved at least partially in the majority of the proteins but the C-terminal substrate-binding domain (SBD) was not. Nine proteins were typical Hsp70s (65–80 kDa) with ABD and SBD, two were lighter lacking partly or totally the SBD, and six were heavier (>80 kDa) with divergent C-terminal domains. We also analyzed exon-intron features, transcriptional variants and protein structure and isoforms, and modality and patterns of expression in various tissues and developmental stages. Evolutionary analyses, including human hsp70 genes and pseudogenes, and other eukaryotic hsp70 genes, showed that six human genes encoding cytosolic Hsp70s and 27 pseudogenes originated from retro-transposition of HSPA8, a gene highly expressed in most tissues and developmental stages.

Conclusion

The human hsp70-gene family is characterized by a remarkable evolutionary diversity that mainly resulted from multiple duplications and retrotranspositions of a highly expressed gene, HSPA8. Human Hsp70 proteins are clustered into seven evolutionary Groups, with divergent C-terminal domains likely defining their distinctive functions. These functions may also be further defined by the observed differences in the N-terminal domain.

Induction of heat shock proteins in differentiated human and rodent neurons by celastrol

Neurodegenerative disorders such as Alzheimer's disease, Parkinson's disease, and amyotrophic lateral sclerosis have been termed protein misfolding disorders that are characterized by the neuronal accumulation of protein aggregates. Manipulation of the cellular stress-response involving induction of heat shock proteins (Hsps) in differentiated neurons offers a therapeutic strategy to counter conformational changes in neuronal proteins that trigger pathogenic cascades resulting in neurodegenerative diseases. Hsps are protein repair agents that provide a line of defense against misfolded, aggregation-prone proteins. These proteins are not induced in differentiated neurons by conventional heat shock. We have found that celastrol, a quinine methide triterpene, induced expression of a wider set of Hsps, including Hsp70B', in differentiated human neurons grown in tissue culture compared to cultured rodent neuronal cells. Hence the beneficial effect of celastrol against human neurodegenerative diseases may exceed its potential in rodent models of these diseases.

The heat shock protein 70 family: Highly homologous proteins with overlapping and distinct functions

The human heat shock protein 70 (Hsp70) family contains at least eight homologous chaperone proteins. Endoplasmatic reticulum and mitochondria have their specific Hsp70 proteins, whereas the remaining six family members reside mainly in the cytosol and nucleus. The requirement for multiple highly homologous although different Hsp70 proteins is still far from clear, but their individual and tissue-specific expression suggests that they are assigned distinct biological tasks. This concept is supported by the fact that mice knockout for different Hsp70 genes display remarkably discrete phenotypes. Moreover, emerging data suggest that individual Hsp70 proteins can bring about non-overlapping and chaperone-independent functions essential for growth and survival of cancer cells. This review summarizes our present knowledge of the individual members of human Hsp70 family and elaborate on the functional differences between the cytosolic/nuclear representatives.

Transactivation of hsp70-1/2 in geldanamycin-treated human non-small cell lung cancer H460 cells: involvement of intracellular calcium and protein kinase C

Geldanamycin is an antitumor drug that binds HSP90 and induces a wide range of heat shock proteins, including HSP70s. In this study we report that the induction of HSP70s is dose-dependent in geldanamycin-treated human non-small cell lung cancer H460 cells. Analysis of the induction of HSP70s specific isoform using LC-ESI-MS/MS analysis and Northern blotting showed that HSP70-1/2 are the major inducible forms under geldanamycin treatment. Transactivation of hsp70-1/2 was determined by electrophoretic mobility-shift assay using heat shock element (HSE) as a probe. The signaling pathway mediators involved in hsp70-1/2 transactivation were screened by the kinase inhibitor scanning technique. Pretreatment with serine/threonine protein kinase inhibitors H7 or H8 blocked geldanamycin-induced HSP70-1/2, whereas protein kinase A inhibitor HA1004, protein kinase G inhibitor KT5823, and myosin light chain kinase inhibitor ML-7 had no effect. Furthermore, the protein kinase C (PKC)-specific inhibitor Ro-31-8425 and the Ca2+-dependent PKC inhibitor Gö-6976 diminished geldanamycin-induced HSP70-1/2, suggesting an involvement of the PKC in the process. In addition, geldanamycin treatment causes a transient increase of intracellular Ca2+. Chelating intracellular Ca2+ with BAPTA-AM or depletion of intracellular Ca2+ store with A23187 or thapsigargin significantly decreased geldanamycin-transactivated HSP70-1/2 expression. Taken together, our results demonstrate that geldanamycin-induced specific HSP70-1/2 isoforms expression in H460 cells through signaling pathway mediated by Ca2+ and PKC.

Characterization of multiple members of the HSP70 family in platyfish culture cells: molecular evolution of stress protein HSP70 in vertebrates

A shift from 28 to 37 degrees C in the incubation temperature of a culture of the platyfish fibroblast cell line, EHS cells (platyfish fibroblast cell line), induced a set of stress proteins. A two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) analysis showed that the cells expressed three genetically distinct forms of heat-shock protein 70 (HSP70) family proteins: heat-inducible forms of HSP70, the constitutively expressed heat-shock cognate protein 70 (HSC70) and its phosphorylated isoform, and the glucose-regulated protein 78 (GRP78). Three different clones encoding two major isoforms of heat-inducible HSP70, platyfish HSP70-1 and HSP70-2, and of the HSC70 were isolated from a platyfish cDNA library. We compared the deduced amino acid sequences of the platyfish HSP70 and HSC70 proteins with those of other vertebrates. Phylogenetic analysis showed that vertebrate HSP70 could be classified into four cluster groups: (a) fish HSP70, with two isoforms of heat-inducible HSP70 in fish, fish HSP70-1 and HSP70-2; (b) the mammalian testis-specific HSP70-related protein HST70; (c) the mammalian heat-inducible HSP70B'; and (d) the mammalian major histocompatibility complex (MHC)-linked HSP70, including the MHC-linked heat-inducible HSP70 and the testis-specific HSP70-related protein. These findings suggest that vertebrate HSP70 was derived from a single ancestral HSP70 gene during vertebrate evolution and that multiple copies of heat-inducible HSP70 were probably evolved during genetic divergence in fish and higher vertebrates.

Microarray analysis of A549 cells infected with rabbitpox virus (RPV): a comparison of wild-type RPV and RPV deleted for the host range gene, SPI-1

A documented consequence of poxvirus infections is global inhibition of host protein synthesis and reduction in mRNA levels. We examined this mRNA decrease by infecting A549 cells, derived from a human lung carcinoma, with rabbitpox virus (RPV), or RPV deleted for the serine protease inhibitor SPI-1 (RPVDeltaSPI-1), which exhibits a growth defect on A549 cells. At various times postinfection, mRNA profiles were analyzed using Affymetrix U95AV2 microarrays. There was a decline in overall cellular mRNA levels beginning at 2.5 hpi, and by 5 hpi, mRNA levels were drastically reduced for the majority of genes. However, several mRNAs increased, including those of heat-shock genes. Finally, a comparison of host mRNA profiles of RPV- to RPVDeltaSPI-1-infected cells revealed subtle differences in mRNA levels at 5 and 12 hpi. In summary, while there was a global decrease of host mRNA levels, the induction of selected mRNAs may be required for a successful poxvirus infection.

Spatial and temporal control of transgene expression through ultrasound-mediated induction of the heat shock protein 70B promoter in vivo

Adenoviral vectors have been constructed that express the transgenes luciferase (Adeno-HSP-Luc) or Fas ligand (Adeno-HSP-FasL) under the control of the heat shock protein 70B (hsp70B) promoter. Cultures infected with Adeno-HSP-Luc transiently expressed high levels of luciferase after heat shock. When cultures infected with Adeno-HSP-FasL were maintained at 37 degrees C, no transgene expression was observed, but when cultures were exposed to heat stress, transgene expression resulted in apoptotic cell death. In vivo, transgene expression was induced by ultrasound-mediated heating of adenovirus-infected tissue. In mice or rats injected with the Adeno-HSP-Luc construct, high levels of localized expression of luciferase activity were observed in regions subjected to ultrasound-mediated irradiation. Adeno-HSP-FasL was administered systemically to mice via the tail vein to evaluate safety. Animals receiving Adeno-HSP-FasL in the absence of ultrasound treatment did not display liver toxicity, whereas animals receiving ultrasound treatment to induce the expression of Fas ligand from the hsp70B promoter had significant increases in serum levels of liver enzymes. These data demonstrate that combining the inducible hsp70B promoter with ultrasound induction allows safe local expression of cytotoxic genes with possible therapeutic utility.

No variation in Hsp70 mRNA level during cardiac surgery in pediatric patients evaluated by semiquantitative RT-PCR

We evaluated mRNA expression of the heat shock protein gene, Hsp70-1, by means of a semiquantitative RT-PCR in atrial tissue specimens from pediatric patients collected before and after cardiopulmonary bypass surgery for congenital heart diseases, to see whether surgical stress may affect the expression level of this mRNA. We studied thirty nine pediatric patients (aged 3 months to 15 years) undergoing surgical correction of congenital heart malformation. Twenty-one patients were affected by the tetralogy of Fallot, two by combined atrioventricular septal defects, six by ventricular septal defect, three by atrial septal defect, two by atrioventricular canal defect, two by pulmonary valve stenosis, one by mitral insufficiency, and one by double-outlet right ventricle. Our results showed no significant changes in the Hsp70-1 mRNA expression in atrial tissue of patients before and after cross-clamping (the mean relative expression after cross-clamping was 1.0+/-0.6 compared to the baseline value). Furthermore, no significant correlations were observed between cross-clamping time and temperature, cardiopulmonary bypass time and mRNA variation. Our study suggests that, during cardioplegia, myocardial tissue does not have an appropriate adaptive response to surgical stress.

The human Hsp70B gene at the HSPA7 locus of chromosome 1 is transcribed but non-functional

The human heat-inducible Hsp70B and Hsp70B' genes were co-localized to 1q23.1 by in situ hybridization. However, though transcripts from Hsp70B could be detected in heat-shocked cells, DNA sequence analyses of both the gene and cDNA copies of the mRNA indicate the gene is non-functional. Moreover, mouse homologues of Hsp70B/B' were not detected by Southern blot analysis, suggesting Hsp70B/B' arose from either Hsp70-1or Hsp70-2 after the divergence of mice and humans.

What do the paralogous regions in the genome tell us about the origin of the adaptive immune system?

During the last decade, our understanding of the immune system of ectothermic vertebrates has advanced significantly. It is now clear that all jawed vertebrates are equipped with the adaptive immune system characterized by the MHC molecules and the rearranging receptors. In contrast, there is no molecular evidence that suggests the existence of adaptive immunity in jawless vertebrates. How did the adaptive immune system emerge? Our recent work suggests that one of the driving forces that enabled the emergence of the adaptive immune system was one or more genome-wide or large-scale chromosomal duplications presumed to have taken place in a common ancestor of jawed vertebrates.

Analysis of heat shock protein 70 in human chromosome 21 containing hybrids

An Hsp70 gene, HspA3, has been given provisional assignment to chromosome 21 based on the heat induced expression of a 70 kDa protein in a Chinese hamster ovary-human hybrid cell line. This assignment has not been supported by hybridization data or by cloning of the gene. The aim of the current study is to clarify this localization. We have analysed a series of Chinese hamster ovary-human hybrid lines containing human chromosome 21 by two-dimensional gel electrophoresis and Western blot analysis with anti-Hsp70 antibodies. Only one of these, hybrid 72532-X6, was found to contain an additional Hsp70 protein. Three other hybrid cell lines spanning different parts of chromosome 21 did not contain any additional Hsp70 proteins. The Hsp70 protein in 72532-X6 is constitutively expressed and is not heat inducible. Southern blot analysis indicates that this protein is not the major human cognate protein, Hsp73 (Hsp70-8), but may be one of the other cognate Hsp70s. Our data indicate that hybrid cell lines containing human chromosome 21 do not express a human Hsp70, as has been reported previously. The recent report that the hybrid cell line used to make this claim also contains other human chromosome fragments leads us to conclude that an Hsp70 gene is not localized on human chromosome.

Genetic aspects of the hsp70 multigene family in vertebrates

The family of genes encoding heat shock proteins of about 70 kDa (hsp70) in vertebrates is reviewed under genetic aspects. After a detailed description of the various hsp70 genes more general characteristics of the organization and evolution of the multigene family are discussed.

Alpha 2-chimerin, an SH2-containing GTPase-activating protein for the ras-related protein p21rac derived by alternate splicing of the human n-chimerin gene, is selectively expressed in brain regions and testes

n-Chimerin (alpha 1-chimerin) is a brain GTPase-activating protein (GAP) for the ras-related p21rac. We now report the occurrence of another form of chimerin, termed alpha 2-chimerin. This is the product of an alternately spliced transcript of the human n-chimerin gene encoding an N-terminal SH2 (src homology 2) domain in addition to the phorbol ester receptor and GAP domains. alpha 1- and alpha 2-chimerin mRNAs were expressed differently. In the rat brain, only alpha 1-chimerin mRNA was expressed in cerebellar Purkinje cells, although both alpha 1- and alpha 2-chimerin mRNAs occurred in neurons in the cerebral cortex, hippocampus, and thalamus. Only alpha 2-chimerin RNA was expressed in rat testes, in early pachytene spermatocytes. A 45-kDa SH2-containing chimerin corresponding to the alpha 2 form was purified from rat brain. As with Escherichia coli 45-kDa recombinant alpha 2-chimerin, purified brain alpha 2-chimerin exhibited racGAP activity which was stimulated by phosphatidylserine. The recombinant SH2 domain bound several 32P-labelled phosphoproteins of PC12 cells, whose phosphorylation increased in response to trophic factors, including nerve growth factor. To examine the relationships of alpha 1- and alpha 2-chimerin transcripts, human genomic DNA clones were characterized. In alpha 2-chimerin mRNA, a 3' splice acceptor site within exon 1 of alpha 1-chimerin mRNA was used, replacing its 5' untranslated region and N-terminal coding sequence. The single human n-chimerin gene was mapped to chromosome 2q31-q32.1, colocalizing with the CRE-BP1 transcription factor gene (2q32). It contained several splice junctions conserved with the sequence-related protein kinase C and bcr genes. alpha 2-Chimerin is only the second SH2-containing GAP and the first example of an SH2 domain generated by alternate splicing.

Alpha 2-chimerin, an SH2-containing GTPase-activating protein for the ras-related protein p21rac derived by alternate splicing of the human n-chimerin gene, is selectively expressed in brain regions and testes

n-Chimerin (alpha 1-chimerin) is a brain GTPase-activating protein (GAP) for the ras-related p21rac. We now report the occurrence of another form of chimerin, termed alpha 2-chimerin. This is the product of an alternately spliced transcript of the human n-chimerin gene encoding an N-terminal SH2 (src homology 2) domain in addition to the phorbol ester receptor and GAP domains. alpha 1- and alpha 2-chimerin mRNAs were expressed differently. In the rat brain, only alpha 1-chimerin mRNA was expressed in cerebellar Purkinje cells, although both alpha 1- and alpha 2-chimerin mRNAs occurred in neurons in the cerebral cortex, hippocampus, and thalamus. Only alpha 2-chimerin RNA was expressed in rat testes, in early pachytene spermatocytes. A 45-kDa SH2-containing chimerin corresponding to the alpha 2 form was purified from rat brain. As with Escherichia coli 45-kDa recombinant alpha 2-chimerin, purified brain alpha 2-chimerin exhibited racGAP activity which was stimulated by phosphatidylserine. The recombinant SH2 domain bound several 32P-labelled phosphoproteins of PC12 cells, whose phosphorylation increased in response to trophic factors, including nerve growth factor. To examine the relationships of alpha 1- and alpha 2-chimerin transcripts, human genomic DNA clones were characterized. In alpha 2-chimerin mRNA, a 3' splice acceptor site within exon 1 of alpha 1-chimerin mRNA was used, replacing its 5' untranslated region and N-terminal coding sequence. The single human n-chimerin gene was mapped to chromosome 2q31-q32.1, colocalizing with the CRE-BP1 transcription factor gene (2q32). It contained several splice junctions conserved with the sequence-related protein kinase C and bcr genes. alpha 2-Chimerin is only the second SH2-containing GAP and the first example of an SH2 domain generated by alternate splicing.

Characterization of a polymorphic heat shock protein 70 gene in swine outside the SLA major histocompatibility complex

To characterize a hitherto unidentified swine Hsp70 gene, a cDNA library was prepared from total RNA isolated from swine lymphocytes and heat-shocked at 42 degrees C for 2 h. One positive clone with a 2.6 kb insert was found. Its sequencing revealed a maximum homology with the human inducible Hsp70B' gene. The genomic polymorphism of this insert was investigated by restriction fragment length polymorphism (RFLP) in an informative family for the major histocompatibility complex SLA. Digestion with PvuII generated 8 bands which were common to both parents, and for the male two extra bands at 0.69 and 0.64 kb. After digestion with PstI, there was also an extra band at 1.6 kb for the male in addition to the seven bands common to both parents. The eleven offsprings' RFLP patterns exhibited all the common parental bands, but four piglets displayed the male's specific bands in addition. All the polymorphic bands belonged to the same locus and segregated independently of SLA. Restriction mapping of the Hsp70 gene indicated the absence of introns, and showed that the polymorphic PstI site was located upstream of the gene's 5' coding region, and the PvuII site inside its coding region.

Chromosomal localization of HSP70 genes in cattle

Five genomic clones representing three HSP70 genes of cattle were biotin labeled and independently hybridized to cattle chromosomes. Fluorescence in situ hybridization localized HSP70-2 to Chromosome (Chr) 23 band 22 (the BoLA region), HSP70-3 to Chr 10 band 34, and HSP70-4 to Chr 3 band 13. Since HSP70-1, a fourth HSP70 gene, is tightly linked with HSP70-2 and the BOLA, HSP70-1 was also localized to Chr 23 band 22. The localization of HSP70-4 is the first assignment of a cattle U6 marker; thus, this entire syntenic group is tentatively placed in cattle Chr 3.

Isolation of four HSP70 genes in the pig and localization on chromosomes 7 and 14

For insight into the general organization of the swine leukocyte antigen (SLA) complex, the swine major histocompatibility complex (MHC), four sequences related to the heat-shock proteins HSP70 were characterized by screening of a pig genomic cosmid library with a swine cDNA HSP70 2.6-kb probe. This yielded three positive clones: HC2.2, HC3.2, and HC4.2. Restriction site maps revealed a large overlap of HC2.2 with HC3.2, whereas HC4.2 was independent. Southern blot hybridization with the 5' section, the central section, and the 3' section of the 2.6-kb probe and also with a swine 4.5-kb HSP70 genomic probe suggested the existence, within the overlapping clones, of three distinct HSP70 sequences encompassing a segment no longer than 22 kb. The HC4.2 clone, which hybridized with the same probes, displayed a single band of 7.3 kb, probably corresponding to one gene only. Fluorescent in situ hybridization on swine chromosome metaphases with the whole HC2.2 or HC4.2 cosmids allowed the assignment of HC2.2 to MHC region on Chromosome (Chr) 7 (Cen-p1.1), and of HC4.2 to Chr 14 (q2.4-2.5). Thus, as in humans, the swine MHC comprises three closely linked HSP70 loci. The presence of additional genes belonging to the same inducible HSP70 gene family can be expected from what is known in humans. The HSP70 gene found here on the pig Chr 14 may be one of these putative unidentified genes.

Syntenic conservation of HSP70 genes in cattle and humans

A phage library of bovine genomic DNA was screened for hybridization with a human HSP70 cDNA probe, and 21 positive plaques were identified and isolated. Restriction mapping and blot hybridization analysis of DNA from the recombinant plaques demonstrated that the cloned DNAs were derived from three different regions of the bovine genome. One region contains two tandemly arrayed HSP70 sequences, designated HSP70-1 and HSP70-2, separated by approximately 8 kb of DNA. Single HSP70 sequences, designated HSP70-3 and HSP70-4, were found in two other genomic regions. Locus-specific probes of unique flanking sequences from representative HSP70 clones were hybridized to restriction endonuclease-digested DNA from bovine-hamster and bovine-mouse somatic cell hybrid panels to determine the chromosomal location of the HSP70 sequences. The probe for the tandemly arrayed HSP70-1 and HSP70-2 sequences mapped to bovine chromosome 23, syntenic with glyoxalase 1, 21 steroid hydroxylase, and major histocompatibility class I loci. HSP70-3 sequences mapped to bovine chromosome 10, syntenic with nucleoside phosphorylase and murine osteosarcoma viral oncogene (v-fos), and HSP70-4 mapped to bovine syntenic group U6, syntenic with amylase 1 and phosphoglucomutase 1. On the basis of these data, we propose that bovine HSP70-1,2 are homologous to human HSPA1 and HSPA1L on chromosome 6p21.3, bovine HSP70-3 is the homolog of an unnamed human HSP70 gene on chromosome 14q22-q24, and bovine HSP70-4 is homologous to one of the human HSPA-6,-7 genes on chromosome 1.