Hsp60 Is Actively Secreted by Human Tumor Cells

Background: Hsp60, a Group I mitochondrial chaperonin, is classically considered an intracellular chaperone with residence in the mitochondria; nonetheless, in the last few years it has been found extracellularly as well as in the cell membrane. Important questions remain pertaining to extracellular Hsp60 such as how generalized is its occurrence outside cells, what are its extracellular functions and the translocation mechanisms that transport the chaperone outside of the cell. These questions are particularly relevant for cancer biology since it is believed that extracellular chaperones, like Hsp70, may play an active role in tumor growth and dissemination. Methodology/Principal Findings: Since cancer cells may undergo necrosis and apoptosis, it could be possible that extracellular Hsps are chiefly the result of cell destruction but not the product of an active, physiological process. In this work, we studied three tumor cells lines and found that they all release Hsp60 into the culture media by an active mechanism independently of cell death. Biochemical analyses of one of the cell lines revealed that Hsp60 secretion was significantly reduced, by inhibitors of exosomes and lipid rafts. Conclusions/Significance: Our data suggest that Hsp60 release is the result of an active secretion mechanism and, since extracellular release of the chaperone was demonstrated in all tumor cell lines investigated, our observations most likel

Aminopeptidase activity of pig spermatozoa before and after incubation with prostasome-like vesicles

At fixed intervals, aliquots of 50 × 10cells were withdrawn and assayed for enzyme activity. Values are mean percentage ± SD. *.<p><b>Copyright information:</b></p><p>Taken from "Prostasome-like vesicles stimulate acrosome reaction of pig spermatozoa"</p><p>http://www.rbej.com/content/6/1/5</p><p>Reproductive biology and endocrinology : RB&E 2008;6():5-5.</p><p>Published online 30 Jan 2008</p><p>PMCID:PMC2266753.</p><p></p

Fluorescence pattern of pig spermatozoa stained with FITC-PNA PI for the assessment of acrosome status and sperm viability

Dead cells showing nuclear red PI fluorescence: C-D. Live cells without PI staining: A acrosome-reacted cells with uniform green FITC-PNA fluorescence of acrosome cap; B: acrosome-unreacted cells with no staining of acrosomal cap (original magnification ×1000).<p><b>Copyright information:</b></p><p>Taken from "Prostasome-like vesicles stimulate acrosome reaction of pig spermatozoa"</p><p>http://www.rbej.com/content/6/1/5</p><p>Reproductive biology and endocrinology : RB&E 2008;6():5-5.</p><p>Published online 30 Jan 2008</p><p>PMCID:PMC2266753.</p><p></p

Impact of Mycobacterium tuberculosis Infection on Human B Cell Compartment and Antibody Responses

Tuberculosis (TB) remains one of the most important health challenges worldwide. Control of the TB epidemic has not yet been achieved because of the lack of an effective vaccine and rapid and sensitive diagnostic approaches, as well as the emergence of drug-resistant forms of M. tuberculosis. Cellular immunity has a pivotal role against M. tuberculosis infection, but the role of humoral immunity is still controversial. We analyzed the frequency, absolute counts, and phenotypic and functional subsets of B lymphocytes in the peripheral blood of patients with active TB and subjects with latent infection compared to healthy donors. Moreover, we analyzed serum levels of total Ig and their IgA, IgM, and IgG isotypes and the titers of preexisting antibodies against a pool of common viral pathogens. FlowCT and unsupervised clusterization analysis show that patients with active TB and LTBI subjects have modest non-significant reduction in the numbers of circulating B lymphocytes as compared to healthy donors. Moreover, LTBI subjects had high percentages of atypical B cell population and lower percentages of naive and switched memory B cells. These findings were supported by gene expression and GSEA analysis. Moreover, there were no differences between active TB patients, LTBI subjects and HD, either in serum levels of total Ig isotypes or in preexisting IgG antibody titers, to ten different antigens from eight common pathogenic viruses, clearly demonstrating that either active or latent M. tuberculosis infection preserves the antibody production capacity of long-lived plasma cells. Thus, our results agree with previous studies reporting unaltered B cell frequencies in the blood of active TB patients and LTBI individuals as compared to healthy controls

Alcoholic Liver Disease: A Mouse Model Reveals Protection by Lactobacillus fermentum

Alcoholism is one of the most devastating diseases with high incidence, but knowledge of its pathology and treatment is still plagued with gaps mostly because of the inherent limitations of research with patients. We developed an animal model for studying liver histopathology, Hsp (heat-shock protein)-chaperones involvement, and response to treatment

Effects of protein-secretion inhibitors on Hsp60 secretion by tumor cells.

<p><b>A</b>) Hsp60 and Hsp70 detected by Western blotting in: (<b>a</b>) immunoprecipitates from conditioned media from untreated (Unt) and inhibitor-treated H292 tumor cells; and (<b>b</b>) whole-cell lysates from H292 cells. The inhibitors are listed on top of the respective lanes. Histograms to the right represent the levels of the Hsps in immunoprecipitates determined in three separate experiments as mean percentages +/− SD of arbitrary units (AU) obtained with NIH image J 1.40 analysis software. * and ** significantly different from untreated control, p<0.005 and p<0.001, respectively. The two inhibitors (listed below the bars) significantly decreased secretion of Hsp60 and Hsp70. Also, the data from whole-cell lysates show that the protein-secretion inhibitors had no detectable effect on Hsp levels inside the cells. <b>B</b>) Hsp60 levels secreted by the H292 tumor cells before and after exposure for 1 hour, followed by a 4 hours recovery period, to protein-secretion inhibitors measured by ELISA in: (<b>a</b>) conditioned media; and (<b>b</b>) exosomes. Histograms represent Hsp60 levels expressed as pg of protein normalized for mL normalised for 10⁶ cells. Data represent mean +/− SD of three different experiments in duplicate. * Significantly different from untreated control, p<0.005. The results, which are in agreement with those obtained by Western blotting, show that the inhibitors tested significantly reduced secretion of Hsp60 by the H292 tumor cells.</p