PubMed Central (PMC3 - NLM DTD)
(2,081,148 recursos)
Archive of life sciences journal literature at the U.S. National Institutes of Health (NIH), developed and managed by NIH's National Center for Biotechnology Information (NCBI) in the National Library of Medicine (NLM).
Mostrando recursos 61 - 80 de 951
61.
Cell typespecific variations in the induction of hsp70 in human leukocytes by feverlike whole body hyperthermia - Oehler, Rudolf; Pusch, Erich; Zellner, Maria; Dungel, Peter; Hergovics, Nicole; Homoncik, Monika; Eliasen, Maja Munk; Brabec, Marianne; Roth, Erich
Fever has been associated with shortened duration and improved survival in infectious disease. The mechanism of this beneficial response is still poorly understood. The heat-inducible 70-kDa heat shock protein (Hsp70) has been associated with protection of leukocytes against the cytotoxicity of inflammatory mediators and with improved survival of severe infections. This study characterizes the induction of Hsp70 by feverlike temperatures in human leukocytes in vitro and in vivo. Using flow cytometry, Hsp70 expression was determined in whole blood samples. This approach eliminated cell isolation procedures that would greatly affect the results. Heat treatment of whole blood in vitro for 2...
62.
Expression of inducible Hsp70 enhances the proliferation of MCF-7 breast cancer cells and protects against the cytotoxic effects of hyperthermia - Barnes, J. A.; Dix, D. J.; Collins, B. W.; Luft, C.; Allen, J. W.
Heat shock proteins (Hsps) are ubiquitous proteins that are induced following exposure to sublethal heat shock, are highly conserved during evolution, and protect cells from damage through their function as molecular chaperones. Some cancers demonstrate elevated levels of Hsp70, and their expression has been associated with cell proliferation, disease prognosis, and resistance to chemotherapy. In this study, we developed a tetracycline-regulated gene expression system to determine the specific effects of inducible Hsp70 on cell growth and protection against hyperthermia in MCF-7 breast cancer cells. MCF-7 cells expressing high levels of Hsp70 demonstrated a significantly faster doubling time (39 hours) compared...
63.
Heat shock factor 1mediated thermotolerance prevents cell death and results in G2/M cell cycle arrest - Luft, J. Christopher; Benjamin, Ivor J.; Mestril, Ruben; Dix, David J.
Mammalian cells respond to environmental stress by activating heat shock transcription factors (eg, Hsf1) that regulate increased synthesis of heat shock proteins (Hsps). Hsps prevent the disruption of normal cellular mitosis, meiosis, or differentiation by environmental stressors. To further characterize this stress response, transformed wild-type Hsf1+/+ and mutant Hsf1?/? mouse embryonic fibroblasts (MEFs) were exposed to (1) lethal heat (45°C, 60 minutes), (2) conditioning heat (43°C, 30 minutes), or (3) conditioning followed by lethal heat. Western blot analysis demonstrated that only Hsf1+/+ MEFs expressed inducible Hsp70s and Hsp25 following conditioning or conditioning and lethal heat. Exposure of either Hsf1+/+ or...
64.
A 14-mer Hsp70 peptide stimulates natural killer (NK) cell activity - Multhoff, Gabriele; Pfister, Karin; Gehrmann, Mathias; Hantschel, Markus; Gross, Catharina; Hafner, Michael; Hiddemann, Wolfgang
Compared with normal cells, tumor cell lines exhibit an unusual plasma membrane localization of heat shock protein 70 (Hsp70). This tumor-selective Hsp70 membrane expression has been found to correlate with an increased sensitivity to lysis mediated by human natural killer (NK) cells that transiently adhere to plastic following cytokine stimulation. A human Hsp70-specific monoclonal antibody (mAb) detects membrane-bound Hsp70 on viable tumor cells and blocks the immune response of NK cells against Hsp70-expressing tumor cells. By peptide scanning (pepscan) analysis, the epitope of this mAb was mapped as the C-terminallocalized 8-mer NLLGRFEL (NLL, amino acids [aa] 454461). Most interestingly, similar...
65.
Increased expression of cytosolic chaperonin CCT in human hepatocellular and colonic carcinoma - Yokota, Shin-ichi; Yamamoto, Yuzo; Shimizu, Kenji; Momoi, Hirohito; Kamikawa, Tatsuhiko; Yamaoka, Yoshio; Yanagi, Hideki; Yura, Takashi; Kubota, Hiroshi
The chaperonin-containing t-complex polypeptide 1 (CCT) is a hetero-oligomeric molecular chaperone that assists in the folding of actin, tubulin, and other cytosolic proteins. We recently reported that the expression level of CCT is closely correlated with growth rates of mammalian cultured cells. Here we examine the levels of CCT subunits and other molecular chaperones in tumor tissues of patients with hepatocelluar and colonic carcinoma, and compare them with nontumor tissues in the same patients. Expression levels of CCT? in tumor tissues was significantly higher than in nontumor tissues in all patients with hepatocellular carcinoma (n = 15) and 83% of...
66.
Killifish metallothionein messenger RNA expression following temperature perturbation and cadmium exposure - Van Cleef-Toedt, Kathleen A.; Kaplan, Lisa A. E.; Crivello, Joseph F.
Metallothionein (MT), a cysteine-rich metal binding protein, is considered to play an essential role in the regulation of intracellular metals. Induction of MT in mammalian and nonmammalian tissues following heavy metal exposure may serve as a defense mechanism and a biomarker of environmental exposure to chemical stressors such as toxic metals. In this study, MT messenger RNA (mRNA) expression was characterized in male and female nonspawning and spawning killifish (Fundulus heteroclitus) following an 8-day exposure to specific sublethal stressors, which included temperature perturbation (26°C or 10°C) and/or 6 ppb of waterborne cadmium chloride (CdCl2). Hepatic, gill, and intestinal MT mRNA,...
67.
The lack of chaperonelike activity of Caenorhabditis elegans Hsp12.2 cannot be restored by domain swapping with human ?B-crystallin - Kokke, Bas P. A.; Boelens, Wilbert C.; de Jong, Wilfried W.
The small heat shock proteins Hsp12.2 and ?B-crystallin differ in that the former occurs as tetramers, without chaperonelike activity, whereas the latter forms multimers and is a good chaperone. To investigate whether the lack of chaperone activity of Hsp12.2 is primarily due to its tetrameric structure or rather to intrinsic sequence features, we engineered chimeric proteins by swapping the N-terminal, C-terminal, and tail regions of Hsp12.2 and ?B-crystallin, designated as n-c-t and N-C-T, respectively. Three of the chimeric sHsps, namely N-c-T, n-c-T, and N-C-t, showed nativelike secondary and quaternary structures as measured by circular dichroism and gel permeation chromatography. Combining...
68.
Induction of stress response renders human tumor cell lines resistant to curcumin-mediated apoptosis: role of reactive oxygen intermediates - Khar, Ashok; Ali, A. Mubarak; Pardhasaradhi, B. V. V.; Varalakshmi, Ch.; Anjum, Rana; Kumari, A. Leela
Curcumin, a well-known dietary pigment derived from Curcuma longa, has been shown to be a potent anti-inflammatory, antioxidant, and anticarcinogenic compound. The present study was designed to investigate the cytotoxic potential of curcumin against a range of human tumor cell lines in an attempt to understand its mechanism of action, which may lead to its possible therapeutic applications. We have shown that different cancer cell lines differ in their sensitivity to curcumin. Cell lines established from malignancies like leukemia, breast, colon, hepatocellular, and ovarian carcinomas underwent apoptosis in the presence of curcumin, whereas cell lines from lung, kidney, prostate, cervix,...
69.
Genomic organization and promoter analysis of the human heat shock factor 2 gene - Nykänen, Päivi; Alastalo, Tero-Pekka; Ahlskog, Johanna; Horelli-Kuitunen, Nina; Pirkkala, Lila; Sistonen, Lea
Heat shock factor 2 (HSF2) is a member of the heat shock transcription factor family, which appears to be activated during differentiation and development rather than on cellular stress. Here we report the isolation and characterization of the human hsf2 gene and its 5?-flanking region. The transcription unit of the human hsf2 gene consists of 13 exons dispersed over 33 kbp of genomic DNA on chromosome 6. The hsf2 mRNA is transcribed from multiple start sites, and initiation from the major site results in a transcript of 2.45 kb. A functional promoter, as determined by the ability to direct expression...
70.
Exercise increases serum Hsp72 in humans - Walsh, R. C.; Koukoulas, I.; Garnham, A.; Moseley, P. L.; Hargreaves, M.; Febbraio, M. A.
Recent evidence suggests that heat shock proteins (Hsps) may have an important systemic role as a signal to activate the immune system. Since acute exercise is known to induce Hsp72 (the inducible form of the 70-kDa family of Hsp) in a variety of tissues including contracting skeletal muscle, we hypothesized that such exercise would result in the release of Hsp72 from stressed cells into the blood. Six humans (5 males, 1 female) ran on a treadmill for 60 minutes at a workload corresponding to 70% of their peak oxygen consumption. Blood was sampled from a forearm vein at rest (R),...
71.
Association of plasma antibodies against the inducible Hsp70 with hypertension and harsh working conditions - Wu, Tangchun; Ma, Jinxiang; Chen, Sheng; Sun, Yehuan; Xiao, Chengfeng; Gao, Yajuan; Wang, Ruibo; Poudrier, Jacques; Dargis, Michele; Currie, R. William; Tanguay, Robert M.
Autoantibodies against certain stress or heat shock proteins (Hsps) may play a role in the pathogenesis and/or prognosis of some diseases. Using immunoblotting with human recombinant Hsps and univariate and multivariate logistic regression models, we have investigated the presence of antibodies against Hsp70, the inducible member of the 70-kDa family of heat shock proteins, and analyzed its possible association with hypertension and working conditions. Plasma and serum were collected from 764 steel mill workers from 6 work sites exposed to (1) severe noise; (2) severe noise and dust; (3) noise, dust, and heat; (4) noise and heat; (5) severe noise...
73.
Overexpression of Hsp25 in K1735 murine melanoma cells enhances susceptibility to natural killer cytotoxicity - Jantschitsch, Christian; Trautinger, Franz; Klosner, Gabriele; Gsur, Andrea; Herbacek, Irene; Micksche, Michael; Kindås-Mügge, Ingela
In the present study we used a murine melanoma model to investigate the effect of the 25-kDa heat shock protein (Hsp25) on natural killer (NK) cytotoxicity. The melanoma lines K1735-Cl23 (low metastatic potential) and K1735-M2 (high metastatic potential) were transfected with hsp25 and a control plasmid. Highly purified interleukin (IL)-2stimulated DX-5+ NK cells showed enhanced lysis of Hsp25-overexpressing K1735-Cl23 targets in comparison with controls. In contrast, there was no difference in susceptibility to lysis by purified IL-2stimulated DX-5+ NK cells between Hsp25-overexpressing and control-transfected K1735-M2 targets. Fluorescence-activated cell sorter analysis revealed that Hsp25 is displayed on the cell surface independently...
74.
Molecular characterization of a Bombyx mori protein disulfide isomerase (bPDI) - Goo, Tae Won; Yun, Eun Young; Hwang, Jae-Sam; Kang, Seok-Woo; Park, Soojung; You, Kwan-Hee; Kwon, O-Yu
We have isolated a complementary deoxyribonucleic acid clone that encodes the protein disulfide isomerase of Bombyx mori (bPDI). This protein has a putative open reading frame of 494 amino acids and a predicted size of 55.6 kDa. In addition, 2 thioredoxin active sites, each with a CGHC sequence, and an endoplasmic reticulum (ER) retention signal site with a KDEL motif were found at the C-terminal. Both sites are typically found in members of the PDI family of proteins. The expression of bPDI messenger ribonucleic acid (mRNA) was markedly increased during ER stress induced by stimulation with calcium ionophore A23187, tunicamycin,...
75.
Heat shock protein 70 is a potent activator of the human complement system - Prohászka, Zoltán; Singh, Mahavir; Nagy, Kálmán; Kiss, Emese; Lakos, Gabriella; Duba, Jenö; Füst, George
According to new hypotheses, extracellular heat shock proteins (Hsps) may represent an ancestral danger signal of cellular death or lysis-activating innate immunity. Recent studies demonstrating a dual role for Hsp70 as both a chaperone and cytokine, inducing potent proinflammatory response in human monocytes, provided support for the hypothesis that extracellular Hsp is a messenger of stress. Our previous work focused on the complement-activating ability of human Hsp60. We demonstrated that Hsp60 complexed with specific antibodies induces a strong classical pathway (CP) activation. Here, we show that another chaperone molecule also possesses complement-activating ability. Solid-phase enzyme-linked immunosorbent assay was applied for...
76.
Overexpression of apolipoprotein J in human fibroblasts protects against cytotoxicity and premature senescence induced by ethanol and tert-butylhydroperoxide - Dumont, Patrick; Chainiaux, Florence; Eliaers, François; Petropoulou, Chariklia; Remacle, José; Koch-Brandt, Claudia; Gonos, Efstathios S.; Toussaint, Olivier
Human diploid fibroblasts (HDFs) exposed to subcytotoxic stresses under H2O2, tert-butylhydroperoxide (t-BHP), and ethanol (EtOH) undergo stress-induced premature senescence (SIPS) characterized by many biomarkers of HDFs replicative senescence. Among these biomarkers are a growth arrest, an increase in the senescence-associated ?-galactosidase activity, a senescent morphology, an overexpression of p21waf-1 and the subsequent inability to phosphorylate pRb, the presence of the common 4977-bp mitochondrial deletion, and an increase in the steady-state level of several senescence-associated genes such as apolipoprotein J (apo J). Apo J has been described as a survival gene against cytotoxic stress. In order to study whether apo J...
77.
Acute stress-induced tissue injury in mice: differences between emotional and social stress - Sánchez, Olga; Arnau, Anna; Pareja, Miguel; Poch, Enric; Ramírez, Ignasi; Soley, Maria
Emotional stress affects cellular integrity in many tissues including the heart. Much less is known about the effects of social stress. We studied the effect of emotional (immobilization with or without cold exposure) or social (intermale confrontation) stress in mice. Tissue injury was measured by means of the release of enzyme activities to blood plasma: lactate dehydrogenase (LDH), creatine kinase (CK), aspartate transaminase (AST), and alanine transaminase (ALT). Tape-immobilization increased all these activities in the plasma. AST-ALT ratio was also increased in these animals. Electrophoretic analysis of CK isoenzymes showed the appearance of CK-MB. These results indicate that the heart...
78.
The eukaryote chaperonin CCT is a cold shock protein in Saccharomyces cerevisiae - Somer, Lilach; Shmulman, Oshrit; Dror, Tali; Hashmueli, Sharon; Kashi, Yechezkel
The eukaryotic Hsp60 cytoplasmic chaperonin CCT (chaperonin containing the T-complex polypeptide1) is essential for growth in budding yeast, and mutations in individual CCT subunits have been shown to affect assembly of tubulin and actin. The present research focused mainly on the expression of the CCT subunits, CCT? and CCT?, in yeast (Saccharomyces cerevisiae). Previous studies showed that, unlike most other chaperones, CCT in yeast does not undergo induction following heat shock. In this study, messenger ribonucleic acid (mRNA) and protein levels of CCT subunits following exposure to low temperatures, were examined. The Northern blot analysis indicated a 3- to 4-fold...
79.
Effect of geldanamycin on androgen receptor function and stability - Vanaja, Donkena Krishna; Mitchell, Susan H.; Toft, David O.; Young, Charles Y. F.
In the ligand-binding inactive state, the steroid receptor heterocomplex contains Hsp90, Hsp70, highmolecular weight immunophilins, and other proteins. Hsp90 acts in association with co-chaperones to maintain the native state of the receptor within the cells. It was reported earlier that Hsp90 might not be as important for the androgen receptor (AR) activity as for the glucocorticoid receptor (GR) and the progesterone receptor (PR) activities. We used the Hsp90 inhibitor geldanamycin (GA) to explore the role of Hsp90 in the function of the AR heterocomplex. GA selectively binds to Hsp90 and inhibits its activity, leading to the loss of steroid receptor...
80.
Xenopus small heat shock proteins, Hsp30C and Hsp30D, maintain heat- and chemically denatured luciferase in a folding-competent state - Abdulle, Rashid; Mohindra, Ashvin; Fernando, Pasan; Heikkila, John J.
In this study we characterized the chaperone functions of Xenopus recombinant Hsp30C and Hsp30D by using an in vitro rabbit reticulocyte lysate (RRL) refolding assay system as well as a novel in vivo Xenopus oocyte microinjection assay. Whereas heat- or chemically denaturated luciferase (LUC) did not regain significant enzyme activity when added to RRL or microinjected into Xenopus oocytes, compared with native LUC, denaturation of LUC in the presence of Hsp30C resulted in a reactivation of enzyme activity up to 80100?%. Recombinant Hsp30D, which differs from Hsp30C by 19 amino acids, was not as effective as its isoform in preventing...
61.
