Pathologic Conditions in Which Surface Hsp60 Has Been Correlated with Pathogenesis.

<p>Pathologic Conditions in Which Surface Hsp60 Has Been Correlated with Pathogenesis.</p

Potential effects of anti-CT-Hsp60 antibodies generated during persistent CT infections.

<p>CT-Hsp60 is released from cells infected with <i>Chlamydia trachomatis</i> (CT), and anti-CT-Hsp60 antibodies are produced by the host's immune system. In turn, these antibodies recognize surface Hsp60 on either stressed or tumor cells and, consequently, cell lysis and organ destruction can occur, determining pathogenesis of a number of diseases (see text for further details). Likewise, immunocomplexes formed by anti-CT-Hsp60 antibodies and CT- (or human-, not shown) Hsp60 can form deposits in the glomerular basal membrane, causing an idiopathic form of glomerulonephritis. Tumor cell lysis can arrest tumorigenesis, in which case it is likely that the infected individual escapes from cancer without having experienced a detectable pathology or symptom.</p

Comparison between the structures of <i>Chlamydia trachomatis</i> (ct-) and human- (h-) Hsp60.

<p>Shown are the positions of the four epitopes with 100% homologies. Circle: apical domain; arrow: intermediate domain; arrowhead: equatorial domain. See text and reference <a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1000552#ppat.1000552-Witkin1" target="_blank">[94]</a> for further details. The images were created with PyMol (<a href="http://pymol.sourceforge.net" target="_blank">http://pymol.sourceforge.net</a>).</p

Hsp60 is integrated in the membrane of exosomes from tumor cells. A–C.

<p>Illustrative data on the exosome preparations utilized in this work. <b>A</b>, Transmission electron microscopy demonstrates that the dimension of isolated vesicles is equal to, or smaller than 100 nm, which is consistent with exosomes. Bar: 100 nm. <b>B</b> and <b>C</b>, acetylcholinesterase (AChEase) and ATPse enzymatic activities, respectively, typical of isolated exosomal vesicles, compared to control (conditioned culture medium). In B, the solid line represents data from exosomes, and the broken line represents results from conditioned culture medium. Vertical axis, AChEase activity in arbitrary units (AU), reflecting 412 nm absorbance; horizontal axis, time of reaction in minutes. In C, 1, marker (positive control); 2, conditioned culture medium; 3, exosomes. <b>D.</b> Treatment with sodium carbonate alone (lane 3, asterisk), or in association with proteinase K buffer (lane 4), does not remove Hsp60 from the exosomes, whereas treatment with Proteinase K does (lane 2). Lane 1, untreated exosomes (positive control).</p

Golgi involvement in Hsp60 secretion from tumor cells. A.

<p>TEM<b>-</b>Immunogold shows Hsp60 (black dots) in tumor cells, including in the Golgi (framed by a dashed rectangle). The arrows show the plasma membrane and arrowheads indicate Hsp60 in it. Bar: 100 nm. <b>B.</b> Extracellular levels of Hsp60 decrease after Brefeldin A (BFA) treatment of the tumor cells, as measured in immunoprecipitates from the conditioned medium (left upper panel). In contrast, Hsp70 levels are not influenced by BFA treatment (left lower panel). Right hand panel: histograms showing densitometric measurements of the Western blots to the left. UT, untreated; A.U.: arbitrary units; asterisk indicates p<0.005. <b>C.</b> ELISA results demonstrate a reduction of Hsp60 levels in the conditioned culture medium from tumor cells after BFA treatment. UT: untreated. <b>D.</b> ELISA results show a reduction of Hsp60 levels in exosomes after BFA treatment of the tumor cells. UT: untreated. Asterisks in C and D, p<0.05. Error bars represent SD.</p

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

NFkB-p65 binding sites in the human <i>hsp60</i> gene.

<p>NFkB-p65 binding sites in the human <i>hsp60</i> gene.</p

Hsps in the bronchial epithelium and lamina propria: Representative images.

<p>Photomicrographs showing frozen sections of bronchial mucosa from a control non smoker (A, C, E) and from a patient with severe stable COPD (B, D, F) immunostained to identify Hsp10 (A, B), Hsp40 (C, D), and Hsp60 (E, F). Nuclei were counterstained with haematoxylin (blue). Cells positive for Hsps are in red. Inset in F shows a cell double stained for neutrophil elastase (red) and Hsp60 (brown). Bar  = 50 microns.</p

Inflammatory markers in bronchial mucosa.

<p>Abbreviations: COPD, chronic obstructive pulmonary disease; MPO, myeloperoxidase; FoxP3: forkhead box P3. Data expressed as median (range). Statistics: Kruskal-Wallis test for multiple comparisons. For comparison between groups the Mann-Whitney U test was applied: #, p<0.05, significantly different from control non smokers; ε, p<0.05, significantly different from control smokers with normal lung function; ^, p<0.05, significantly different from mild/moderate COPD. The exact “p” values for comparison between groups are given in the Results section.</p

Correlations between neutrophils and Hsp60.

<p>Regression analysis between number of Hsp60 positive cells (vertical axis) and number of neutrophils (horizontal axis), panels A and B, and between number of Hsp60 positive cells (vertical axis) and number of MPO positive neutrophils (horizontal axis), panels C and D, in the lamina propria of all smokers (panels A and C) and of patients with COPD alone, considered as a single group (panels B and D).</p