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

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

Paeoniflorin eliminates a mutant AR via NF-YA-dependent proteolysis in spinal and bulbar muscular atrophy.

The accumulation of abnormal proteins is a common characteristic of neurodegenerative diseases. This accumulation reflects a severe disturbance of cellular homeostasis in pathogenic protein clearance. Here, we demonstrated that the activation of the two major proteolytic machineries, the molecular chaperone-ubiquitin proteasome system (UPS) and the autophagy system, were simultaneously enhanced by paeoniflorin (PF), a major component of Paeonia plants, and exerted therapeutic effects in models of spinal and bulbar muscular atrophy (SBMA).

Common gene expression patterns responsive to mild temperature hyperthermia in normal human fibroblastic cells.

Purpose: Heat stress induces complex cellular responses, and its detailed molecular mechanisms still remain to be clarified. The objective of this study was to investigate the molecular mechanisms underlying cellular responses to mild hyperthermia (MHT) in normal human fibroblastic (NHF) cells.

Materials And Methods: Cells were treated with MHT (41°C, 30 min) and then cultured at 37°C.

Gene networks related to the cell death elicited by hyperthermia in human oral squamous cell carcinoma HSC-3 cells.

Local hyperthermia (HT) for various types of malignant tumors has shown promising antitumor effects. To confirm the detailed molecular mechanism underlying cell death induced by HT, gene expression patterns and gene networks in human oral squamous cell carcinoma (OSCC) cells were examined using a combination of DNA microarray and bioinformatics tools. OSCC HSC-3 cells were treated with HT at 44˚C for 90 min or mild hyperthermia (MHT) at 42˚C for 90 min, followed by culturing at 37˚C for 0-24 h.

Identification of biological functions and gene networks regulated by heat stress in U937 human lymphoma cells.

Although cancer cells exposed to temperatures >42.5°C undergo cell death as the temperature rises, exposure of up to 42.5°C induces slight or no cytotoxicity.

Protective effect of a molecular chaperone inducer, paeoniflorin, on the HCl- and ethanol-triggered gastric mucosal injury.

Aims: We previously found that paeoniflorin, a major constituent of Paeonia lactiflora Pall, could induce heat shock proteins (HSPs) in cultured mammalian cells without apparent toxicity (Yan et al. 2004). We here investigated the induction of HSPs by paeoniflorin in mouse stomach and the effect of paeoniflorin on the HCl- and ethanol-triggered gastric mucosal injury in mouse.

Gene networks involved in apoptosis induced by hyperthermia in human lymphoma U937 cells.

To define the molecular mechanisms that mediate hyperthermia-induced apoptosis, we performed microarray and computational gene expression analyses. U937 cells, a human myelomonocytic lymphoma cell line, were treated with hyperthermia at 42 degrees C for 90 min and cultured at 37 degrees C. Apoptotic cells ( approximately 15%) were seen 6 h after hyperthermic treatment, and elevated expression of heat shock proteins (HSPs) including Hsp27, Hsp40, and Hsp70 was detected, following the activation of heat shock factor-1.

Reinvestigation of the effect of carbenoxolone on the induction of heat shock proteins.

Carbenoxolone (CBX) is a semisynthetic derivative of the licorice root substance glycyrrhizinic acid and has been previously reported to induce only heat shock protein 70 [Hsp70, HSPA1A (the systematic name of heat shock protein is given in the parenthesis after each HSP, according to the recent nomenclature guidelines, Kampinga et al., Cell Stress Chaperones, 14:105-111, 2008) but not other heat shock proteins (HSPs) (Nagayama et al., Life Sci.

Genes and genetic networks responsive to mild hyperthermia in human lymphoma U937 cells.

In this study, to better understand the molecular mechanism underlying cellular responses to mild hyperthermia, we investigated gene expression patterns and genetic networks in human myelomonocytic lymphoma U937 cells using high-density oligonucleotide microarrays and computational gene expression analysis tools. The cells were incubated at 41 degrees C for 30 min (mild hyperthermia treatment) and then at 37 degrees C for 0-6 h. Although the mild hyperthermia treatment of the cells did not induce apoptosis, significant increases in the protein expression levels of heat shock proteins (HSPs), namely, Hsp27, Hsp40 and Hsp70, were observed following the activation of heat shock factor-1.

Identification of genes responsive to paeoniflorin, a heat shock protein-inducing compound, in human leukemia U937 cells.

Purpose And Background: Paeoniflorin (PF) isolated from peony root (Paeoniae radix) has been used as a herbal medicine in East Asia for its anti-allergic, anti-inflammatory, and immunoregulatory effects. PF is known to cause apoptosis and to be a chemical heat shock protein (HSP) inducer. With this information, the effects on the gene expression in human leukemia U937 cells treated with PF were investigated.

Overexpression of heat shock protein 70 restores the structural stability and functional defects of temperature-sensitive mutant of large T antigen at nonpermissive temperature.

The effects of heat shock protein 70 (Hsp70), a molecular chaperone, on the degradation and functional alterations of a mutant large T antigen induced by a nonpermissive temperature were examined. In this study, mouse tracheal epithelial TM02-3 cells harboring temperature-sensitive simian virus 40 large T antigen and stable TM02-3 cells overexpressing human Hsp70 and/or Hsp40 were used. Although the temperature shift from 33 degrees C (permissive temperature) to 39 degrees C (nonpermissive temperature) induced increases in the endogenous chaperones including Hsp70 and Hsp40, degradation of the T antigen, activation of the p53-p21(waf1) pathway, and an arrest of cell growth were observed in the mock cells.

Enhanced expression of heat shock proteins in gradually dying cells and their release from necrotically dead cells.

Heat shock proteins (HSPs) have molecular chaperone functions in protein biogenesis as well as cytoprotective functions against deleterious environmental stresses, and they work mainly inside of the cells. HSPs are usually induced in living cells that have been exposed to mild stresses or have recovered from severe stresses. Here, we show the enhanced synthesis of HSPs in gradually and necrotically dying cells that were treated with a high concentration of acrylamide (10 mM).

Paeoniflorin, a novel heat shock protein-inducing compound.

Heat shock proteins (HSPs) are induced by various physical, chemical, and biological stresses. HSPs are known to function as molecular chaperones, and they not only regulate various processes of protein biogenesis but also function as lifeguards against proteotoxic stresses. Because it is very useful to discover nontoxic chaperone-inducing compounds, we searched for them in herbal medicines.

Formation of aggresome-like structures in herpes simplex virus type 2-infected cells and a potential role in virus assembly.

Herpes simplex virus (HSV) is a large, enveloped DNA virus that replicates in the nucleus and is assembled in the cytoplasm to the mature infectious virion. In this study, we present evidence that, in HSV-2-infected cells, some tegument proteins (UL46 and VP16) and newly synthesized nucleocapsids accumulate in a juxtanuclear domain sharing characteristics with aggresomes, cellular structures formed in response to misfolded proteins [J. Cell Biol.

Reinvestigation of the requirement of cytosolic ATP for mitochondrial protein import.

Protein import into mitochondria requires the energy of ATP hydrolysis inside and/or outside mitochondria. Although the role of ATP in the mitochondrial matrix in mitochondrial protein import has been extensively studied, the role of ATP outside mitochondria (external ATP) remains only poorly characterized. Here we developed a protocol for depletion of external ATP without significantly reducing the import competence of precursor proteins synthesized in vitro with reticulocyte lysate.

Expression of heat shock protein (Hsp) 70 and Hsp 40 in gastric cancer.

Heat shock proteins (Hsp) 70 and Hsp 40 are stress proteins that cooperate as chaperones in mammalian cells. We determined the expression of Hsp 70 and Hsp 40 in 81 gastric cancers. Immunoreactivities to Hsp 70 and Hsp 40 were detected in 67.

Expression of heat shock protein (Hsp) 70 and Hsp 40 in colorectal cancer.

Heat shock protein (Hsp) 70 and Hsp 40 are stress proteins that cooperate as chaperones in mammalian cells. The present study was designed to determine the expression levels of Hsp 70 and Hsp 40 in colorectal cancer by immunohistochemistry and Western blot analysis. Among 50 colorectal cancer tissues studied, 80% and 14% of tumors showed specific immunoreactivity to Hsp 70 and Hsp 40, respectively.

Heat shock protein 70 binds caspase-activated DNase and enhances its activity in TCR-stimulated T cells.

DNA fragmentation is a hallmark of cells undergoing apoptosis and is mediated mainly by the caspase-activated DNase (CAD or DNA-fragmentation factor 40 [DFF40]), which is activated when released from its inhibitor protein (ICAD or DFF45) upon apoptosis signals. Here we analyzed the effect of heat shock protein 70 (Hsp70) on CAD activity in T-cell receptor (TCR)-induced apoptosis using a T-cell line (TAg-Jurkat). Overexpression of Hsp70 significantly augmented the apoptotic cell death as well as DNA fragmentation in CD3/CD28- or staurosporine-stimulated cells.

Hsp105alpha suppresses the aggregation of truncated androgen receptor with expanded CAG repeats and cell toxicity.

Spinal and bulbar muscular atrophy (SBMA) is a neurodegenerative disorder caused by the expansion of a polyglutamine tract in the androgen receptor (AR). The N-terminal fragment of AR containing the expanded polyglutamine tract aggregates in cytoplasm and/or in nucleus and induces cell death. Some chaperones such as Hsp40 and Hsp70 have been identified as important regulators of polyglutamine aggregation and/or cell death in neuronal cells.

Phosphorylation of cytokeratin 17 by herpes simplex virus type 2 US3 protein kinase.

We previously reported the establishment of an HEp2 cell line which expresses the US3 protein kinase (PK) of herpes simplex virus type 2 (HSV-2) upon induction with IPTG. Here we report that expression, phosphorylation and ubiquitination of cytokeratin 17 (CK17) are enhanced in US3-expressing HEp2 cells. In vitro kinase and co-immunoprecipitation assays provided evidence that US3 PK directly phosphorylates CK17.

Hsp70 and Hsp40 improve neurite outgrowth and suppress intracytoplasmic aggregate formation in cultured neuronal cells expressing mutant SOD1.

Mutations of the superoxide dismutase 1 (SOD1) gene cause familial amyotrophic lateral sclerosis (FALS). Intracytoplasmic aggregate formation consisting of mutant SOD1 is the histological hallmark of FALS. Since a previous report revealed that Hsp70 reduced aggregate formation and cell death in a cell model of FALS, here we examined the combined effects of Hsp70 and its cofactor, Hsp40, on a cell model of FALS.

Herpes simplex virus type 2 UL14 gene product has heat shock protein (HSP)-like functions.

The HSV-2 UL14 gene encodes a 32 kDa protein that is a minor component of the viral tegument. The protein relocates other viral proteins such as VP26 and UL33 protein into the nuclei of transiently coexpressing cells (Yamauchi et al., 2001).