Search

Due to the lipophilicity of the metal-ion receptor, previously reported Cu(I)-selective fluorescent probes form colloidal aggregates, as revealed by dynamic light scattering. To address this problem, we have developed a hydrophilic triarylpyrazoline-based fluorescent probe, CTAP-2, that dissolves directly in water and shows a rapid, reversible, and highly selective 65-fold fluorescence turn-on response to Cu(I) in aqueous solution. CTAP-2 proved to be sufficiently sensitive for direct in-gel detection of Cu(I) bound to the metallochaperone Atox1, demonstrating the potential for cation-selective fluorescent probes to serve as tools in metalloproteomics for identifying proteins with readily accessible metal-binding sites.

In microbial communities, extracellular polymeric substances (EPS), also called the extracellular matrix, provide the spatial organization and structural stability during biofilm development. One of the major components of EPS is protein, but it is not clear what specific functions these proteins contribute to the extracellular matrix or to microbial physiology. To investigate this in biofilms from an extremely acidic environment, we used shotgun proteomics analyses to identify proteins associated with EPS in biofilms at two developmental stages, designated DS1 and DS2. The proteome composition of the EPS was significantly different from that of the cell fraction, with more than 80% of the cellular proteins underrepresented or undetectable in EPS. In contrast, predicted periplasmic, outer membrane, and extracellular proteins were overrepresented by 3- to 7-fold in EPS. Also, EPS proteins were more basic by ∼2 pH units on average and about half the length. When categorized by predicted function, proteins involved in motility, defense, cell envelope, and unknown functions were enriched in EPS. Chaperones, such as histone-like DNA binding protein and cold shock protein, were overrepresented in EPS. Enzymes, such as protein peptidases, disulfide-isomerases, and those associated with cell wall and polysaccharide metabolism, were also detected. Two of these enzymes, identified as β-N-acetylhexosaminidase and cellulase, were confirmed in the EPS fraction by enzymatic activity assays. Compared to the differences between EPS and cellular fractions, the relative differences in the EPS proteomes between DS1 and DS2 were smaller and consistent with expected physiological changes during biofilm development.

Background: DYT1 dystonia is an autosomal dominant neurological condition caused by a mutation that removes a single glutamic acid residue (ΔE) from the torsinA (torA) AAA+ protein. TorA appears to possess a nuclear envelope (NE) localized activity that requires Lamina-Associated-Polypeptide 1 (LAP1), which is an inner nuclear membrane localized torA-binding partner. Although hypoactive, the DYT1 dystonia torA-ΔE isoform often concentrates in the NE, suggesting that torA-ΔE also interacts with an NE-localized binding partner., Results: We confirm that NE-localized torA-ΔE does not co-immunoprecipitate with LAP1, and find that torA-ΔE continues to concentrate in the NE of cells that lack LAP1. Instead, we find that variability in torA-ΔE localization correlates with the presence of the SUN-domain and Nesprin proteins that assemble into the LINC complex. We also find that siRNA depletion of SUN1, but not other LINC complex components, removes torA-ΔE from the NE. In contrast, the LAP1-dependent NE-accumulation of an ATP-locked torA mutant is unaffected by loss of LINC complex proteins. This SUN1 dependent torA-ΔE localization requires the torA membrane association domain, as well as a putative substrate-interaction residue, Y147, neither of which are required for torA interaction with LAP1. We also find that mutation of these motifs, or depletion of SUN1, decreases the amount of torA-WT that colocalizes with NE markers, indicating that each also underlies a normal NE-localized torA binding interaction., Conclusions: These data suggest that the disease causing ΔE mutation promotes an association between torA and SUN1 that is distinct to the interaction between LAP1 and ATP-bound torA. This evidence for two NE-localized binding partners suggests that torA may act on multiple substrates and/or possesses regulatory co-factor partners. In addition, finding that the DYT1 mutation causes abnormal association with SUN1 implicates LINC complex dysfunction in DYT1 dystonia pathogenesis, and suggests a gain-of-function activity contributes to this dominantly inherited disease.

A class of peptides from the bombolitin family, not previously identified for nitroaromatic recognition, allows near-infrared fluorescent single-walled carbon nanotubes to transduce specific changes in their conformation. In response to the binding of specific nitroaromatic species, such peptide-nanotube complexes form a virtual "chaperone sensor," which reports modulation of the peptide secondary structure via changes in single-walled carbon nanotubes, near-infrared photoluminescence. A split-channel microscope constructed to image quantized spectral wavelength shifts in real time, in response to nitroaromatic adsorption, results in the first single-nanotube imaging of solvatochromic events. The described indirect detection mechanism, as well as an additional exciton quenching-based optical nitroaromatic detection method, illustrate that functionalization of the carbon nanotube surface can result in completely unique sites for recognition, resolvable at the single-molecule level.

Missense mutations of SOD1 are linked to familial amyotrophic lateral sclerosis (FALS) through a yet-to-be identified toxic-gain-of-function. One of the proposed mechanisms involves enhanced aggregate formation. However, a recent study showed that dual transgenic mice overexpressing both G93A and CCS copper chaperone (G93A/CCS) exhibit no SOD1-positive aggregates yet show accelerated FALS symptoms with enhanced mitochondrial pathology compared to G93A mice. Using a dicistronic mRNA to simultaneously generate hSOD1 mutants, G93A, A4V and G85R, and hCCS in AAV293 cells, we revealed: (i) CCS is degraded primarily via a macroautophagy pathway. It forms a stable heterodimer with inactive G85R, and via its novel copper chaperone-independent molecular chaperone activity facilitates G85R degradation via a macroautophagy-mediated pathway. For active G93A and A4V, CCS catalyzes their maturation to form active and soluble homodimers. (ii) CCS reduces, under non-oxidative conditions, yet facilitates in the presence of H(2)O(2), mitochondrial translocation of inactive SOD1 mutants. These results, together with previous reports showing FALS SOD1 mutants enhanced free radical-generating activity, provide a mechanistic explanation for the observations with G93A/CCS dual transgenic mice and suggest that free radical generation by FALS SOD1, enhanced by CCS, may, in part, be responsible for the FALS SOD1 mutant-linked aggregation, mitochondrial translocation, and degradation., (Published by Elsevier Inc.)

Objective: PIAS3 is the endogenous inhibitor of STAT3, which has been implicated in the pathogenesis of many cancers. However, the effect of PIAS3 on human tumors remains elusive. The aim of this article is to investigate the expression of PIAS3 in gastric carcinoma and its adjacent non-tumor tissues., Methods: Samples were taken from 30 patients with gastric cancer, which included tumor or non-tumor tissues in the excised sections. The expression of PIAS3 protein was detected by immunocytochemistry, and that of mRNA by in situ hybridization. The results were semi-quantitative analyzed by using cell count and color depth to stage., Results: The expression levels of PIAS3 protein and mRNA were significantly lower in gastric cancerous tissues than in its adjacent non-tumor tissues, and had a close relation with tumor size and differentiation, but not with age, gender and lymphatic metastasis in gastric carcinoma. The more large in size and poorly in differentiation, the more low PIAS3 expression was., Conclusion: Loss of PIAS3 expression may be an important characteristic of gastric cancer and suggest vicious degree of the tumor., (Copyright © 2011 Elsevier Masson SAS. All rights reserved.)

The cell envelope of Escherichia coli is an essential structure that modulates exchanges between the cell and the extra-cellular milieu. Previous proteomic analyses have suggested that it contains a significant number of proteins with no annotated function. To gain insight into these proteins and the general organization of the cell envelope proteome, we have carried out a systematic analysis of native membrane protein complexes. We have identified 30 membrane protein complexes (6 of which are novel) and present reference maps that can be used for cell envelope profiling. In one instance, we identified a protein with no annotated function (YfgM) in a complex with a well-characterized periplasmic chaperone (PpiD). Using the guilt by association principle, we suggest that YfgM is also part of the periplasmic chaperone network. The approach we present circumvents the need for engineering of tags and protein overexpression. It is applicable for the analysis of membrane protein complexes in any organism and will be particularly useful for less-characterized organisms where conventional strategies that require protein engineering (i.e., 2-hybrid based approaches and TAP-tagging) are not feasible.

Objective: To discuss protein marks expressed differentially in placenta of Down's syndrome by means of proteomics., Methods: We collected placenta of 18 patients (from March 2009 to December 2009 at Beijing Obstetrics and Gynecology Hospital), and divided them into two groups, one was 10 patients with fetal Down's syndrome, the other was normal pregnancies (normal chromosome) with other diseases. We separated proteins expressed in placentas of two groups by two-dimensional difference gel electrophoresis (2D-DIGE), and then analyzed the differential protein spots by software Decyder 6.5, then, spots differentially expressed by 1.5 fold or more were analyzed by matrix assisted laser desorption ionization-time of flight-mass spectrometry (MALDI-TOF-MS). In the end, the differential expressional levels of partially identified proteins were validated by western blot analysis., Results: (1) Differential proteins of two groups protein spots of placentas separated by 2D-DIGE were analyzed by software Decyder 6.5 (these colored lights scattered in the image were protein spots), a total of 56 spots out of 352 were differentially expressed (P < 0.05) in two groups. We analyzed 17 protein spots (12 protein spots were over-expressed and 5 protein spots were down-expressed) differentially expressed by 1.5 fold or more by MALDI-TOF-MS. (2) Protein matching after searching protein database, 17 protein spots turn out to be 10 proteins. Four kinds [superoxide dismutase 1 (SOD1), peroxiredoxin 6 (PRDX6), heat shock protein 27 (HSP27), endoplasmic reticulum protein 29 (ERP29)] of them were validated by western blot analysis, the group of fetal Down's syndrome were 0.74 ± 0.12, 0.29 ± 0.10, 0.53 ± 0.16, 0.20 ± 0.09, the group of normal pregnancies were 0.51 ± 0.08, 0.34 ± 0.16, 0.18 ± 0.07, 0.35 ± 0.09, the results confirmed the observed changes in proteomics., Conclusions: Compared with normal pregnancies, there were differential proteins expressed in placenta of Down's syndrome. This approach might provide new screening markers in use for prediction of Down's syndrome, however, further study should be done to make these 4 proteins (SOD1, HSP27, ERP29, PRDX6) be new screening markers.

We describe a computational protocol to identify functional modules and pathway relationship of chaperones based on physical interaction data derived from high-throughput proteomic experiments. The protocol first identifies interacting proteins shared by the different chaperone systems to organize the chaperones into functional modules. The chaperone functional modules represent groups of chaperones that are involved in mediating the folding of the shared interacting proteins. Either the chaperones in a module can function along a single folding pathway of a given substrate protein or the substrate protein might have two or more different folding pathways that the chaperones act on independently. As described in our computational protocol, probabilities of these pathway relationships between two chaperones in a two-component chaperone module can be determined using whole-genome expression and cellular pathways as reference. This protocol is potentially useful for identifying functional modules and pathway relationships in other biological systems that involve multiple proteins with many identified interactions.

ATP-dependent proteases unfold their substrates and then refold (via chaperone activity) or degrade (via protease activity) them. The proteases choose between these two activities by selecting their substrates; however, little is known about their substrate selection mechanism. The present study attempts to clarify this mechanism by investigating the role of the Escherichia coli (E. coli) ATP-dependent protease ClpAP. To address this, a reaction system that can measure both chaperone and protease activities simultaneously must be constructed. However, the chaperone activities cannot be evaluated in the presence of protease units. Green fluorescent protein (GFP) is usually used as a model substrate of ClpAP; the fluorescence decrease reflects the degradation of substrates. However, it is difficult to evaluate the chaperone activity of ClpAP using this system, because it cannot distinguish between intact and refolded substrates. Therefore, it is necessary to evaluate the exact unfolding activity while avoiding restoration of substrate spectroscopic characteristics due to chaperone activity. In this study, E. coli Ferredoxin (Fd) was used as a new model substrate for ClpAP to evaluate its unfolding activity. Intact and refolded substrates may be distinguished by the existence of an Fd Fe-S cluster. To verify this hypothesis, the absorption spectrum of Fd complexed with ClpA, the chaperone unit of ClpAP, was measured. A decrease in two peaks derived from the Fe-S cluster was observed, indicating that the Fe-S cluster of Fd was disrupted by the ClpA chaperone. This reaction system should prove useful to evaluate the exact unfolding activity of ATP-dependent proteases.

Mass spectrometry (MS) is a powerful analytical tool for proteomics research and drug and biomarker discovery. MS enables identification and quantification of known and unknown compounds by revealing their structural and chemical properties. Proper sample preparation for MS-based analysis is a critical step in the proteomics workflow because the quality and reproducibility of sample extraction and preparation for downstream analysis significantly impact the separation and identification capabilities of mass spectrometers. The highly expressed proteins represent potential biomarkers that could aid in diagnosis, therapy, or drug development. Because the proteome is so complex, there is no one standard method for preparing protein samples for MS analysis. Protocols differ depending on the type of sample, source, experiment, and method of analysis. Molecular chaperones play significant roles in almost all biological functions due to their capacity for detecting intracellular denatured/unfolded proteins, initiating refolding or denaturation of such malfolded protein sequences and more recently for their role in the extracellular milieu as chaperokines. In this chapter, we describe the latest techniques for quantitating the expression of molecular chaperones in human clinical samples.

Due to the potential for increasing ocean temperatures to detrimentally impact reef-building corals, there is an urgent need to better understand not only the coral thermal stress response, but also natural variation in their sub-cellular composition. To address this issue, while simultaneously developing a molecular platform for studying one of the most common Taiwanese reef corals, Seriatopora hystrix, 1,092 cDNA clones were sequenced and characterized. Subsequently, RNA, DNA and protein were extracted sequentially from colonies exposed to elevated (30°C) temperature for 48 hours. From the RNA phase, a heat shock protein-70 (hsp70)-like gene, deemed hsp/c, was identified in the coral host, and expression of this gene was measured with real-time quantitative PCR (qPCR) in both the host anthozoan and endosymbiotic dinoflagellates (genus Symbiodinium). While mRNA levels were not affected by temperature in either member, hsp/c expression was temporally variable in both and co-varied within biopsies. From the DNA phase, host and Symbiodinium hsp/c genome copy proportions (GCPs) were calculated to track changes in the biological composition of the holobiont during the experiment. While there was no temperature effect on either host or Symbiodinium GCP, both demonstrated significant temporal variation. Finally, total soluble protein was responsive to neither temperature nor exposure time, though the protein/DNA ratio varied significantly over time. Collectively, it appears that time, and not temperature, is a more important driver of the variation in these parameters, highlighting the need to consider natural variation in both gene expression and the molecular make-up of coral holobionts when conducting manipulative studies. This represents the first study to survey multiple macromolecules from both compartments of an endosymbiotic organism with methodologies that reflect their dual-compartmental nature, ideally generating a framework for assessing molecular-level changes within corals and other endosymbioses exposed to changes in their environment.

Molecular chaperones, including the extracellular protein clusterin (CLU), play a significant role in maintaining proteostasis; they have a unique capacity to bind and stabilize non-native protein conformations, prevent aggregation, and keep proteins in a soluble folding-competent state. In this study, we investigated amyloid-infiltrated cardiac tissue for the presence of CLU and measured serum levels of CLU in patients with and without amyloidotic cardiomyopathy (CMP). Cardiac tissues containing amyloid deposits composed of either transthyretin (TTR) or Ig light chain from nine patients with amyloidotic CMP were examined for the presence of CLU using immunohistochemical techniques. CLU staining coincided with the extracellular myocardial amyloid deposits in tissues from patients with familial TTR, senile systemic, and Ig light chain amyloidosis. The association of CLU with cardiac amyloid deposits was confirmed by immunogold electron microscopy. Serum concentrations of CLU were measured in familial TTR, senile systemic, and Ig light chain amyloidosis patient groups and compared with both age-matched healthy controls and with patients with CMP unrelated to amyloid disease. Subset analysis of disease cohorts, based on cardiac involvement, indicated that decreased serum CLU concentrations were associated with amyloidotic CMP. Taken together, these results suggest that CLU may play a pathogenetic role in TTR and Ig light chain amyloidoses and amyloidotic CMP., (Copyright © 2011 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.)

Muscle atrophy occurring in several pathophysiological conditions determines decreases in muscle protein synthesis, increases in the rate of proteolysis and changes in muscle fiber composition. To determine the effect of muscle atrophy induced by hindlimb unloading (HU) on membrane proteins from rat soleus, a proteomic approach based on two-dimensional Blue Native/SDS-PAGE was performed. Proteomic analysis of normal and HU soleus muscle demonstrates statistically significant changes in the relative level of 36 proteins. Among the proteins identified by mass spectrometry, most are involved in pathways associated with muscle fuel utilization, indicating a shift in metabolism from oxidative to glycolytic. Moreover, immunoblotting analysis revealed an increase in aquaporin-4 (AQP4) water channel and an alteration of proteins belonging to the dystrophin-glycoprotein complex (DGC). AQP4 and DGC are regulated in soleus muscle subjected to simulated microgravity in response to compensatory mechanisms induced by muscle atrophy, and they parallel the slow-to-fast twitch conversion that occurs in soleus fibers during HU. In conclusion, the alterations of soleus muscle membrane proteome may play a pivotal role in the mechanisms involved in disuse-induced muscle atrophy.

Protein-arginine methylation is one of the modifications that yields mono and dimethyl (asymmetric or symmetric) arginine residues in proteins. Previously, we found that asymmetric arginine methylation is decreased proportionately with a decrease of cell proliferation potential of cells, and such arginine methylation is greatest in immortalized cells, followed by normal young cells, and lowest in replicatively senescent cells. Using an asymmetric dimethyl-arginine-specific antibody, we identified arginine-methylated proteins in these cell types by immunoprecipitation and 2-D immunoblotting followed by MS. As a result, arginine methylation of chaperone molecules and RNA-binding proteins was differentially regulated between immortalized or young cells and senescent cells. Immortalized cells had significantly higher levels of methyl-accepting proteins, such as cleavage stimulation factor 2 (CstF2) and heterogeneous nuclear ribonucleoprotein (hnRNP) R, than young cells. However, senescent cells contained hypomethylated CstF2, hnRNP K, and chaperone containing TCP1 subunit 7, as well as decreased hnRNP R level. Further, significant reduction of arginine modification in CstF2 and chaperone containing TCP1 subunit 7 was observed in prematurely senescent fibroblasts, induced by treatment with adenosine dialdehyde, a transmethylation inhibitor, or subcytotoxic concentration of H(2)O(2). These results suggest that asymmetric modification of RNA-binding proteins and molecular chaperones plays an essential role in maintaining cell proliferation capability.

Background: Molecular chaperones have been shown to be important in the growth of the malaria parasite Plasmodium falciparum and inhibition of chaperone function by pharmacological agents has been shown to abrogate parasite growth. A recent study has demonstrated that clinical isolates of the parasite have distinct physiological states, one of which resembles environmental stress response showing up-regulation of specific molecular chaperones., Methods: Chaperone networks operational in the distinct physiological clusters in clinical malaria parasites were constructed using cytoscape by utilizing their clinical expression profiles., Results: Molecular chaperones show distinct profiles in the previously defined physiologically distinct states. Further, expression profiles of the chaperones from different cellular compartments correlate with specific patient clusters. While cluster 1 parasites, representing a starvation response, show up-regulation of organellar chaperones, cluster 2 parasites, which resemble active growth based on glycolysis, show up-regulation of cytoplasmic chaperones. Interestingly, cytoplasmic Hsp90 and its co-chaperones, previously implicated as drug targets in malaria, cluster in the same group. Detailed analysis of chaperone expression in the patient cluster 2 reveals up-regulation of the entire Hsp90-dependent pro-survival circuitries. In addition, cluster 2 also shows up-regulation of Plasmodium export element (PEXEL)-containing Hsp40s thought to have regulatory and host remodeling roles in the infected erythrocyte., Conclusion: In all, this study demonstrates an intimate involvement of parasite-encoded chaperones, PfHsp90 in particular, in defining pathogenesis of malaria.

The 26S proteasome is a large multiprotein complex involved in the regulated degradation of ubiquitinated proteins in the cell. The 26S proteasome has been shown to control an increasing number of essential biochemical mechanisms of the cellular lifecycle including DNA synthesis, repair, transcription, translation, and cell signal transduction. Concurrently, it is increasingly seen that malfunction of the ubiquitin proteasome system contributes to the pathogenesis of disease. The recent identification of four molecular chaperones, in addition to five previously identified chaperones, have provided mechanistic insight into how this cellular megastructure is assembled in the cell. These data, together with new insights into the structure and function of the proteasome, provide a much better understanding of this complex protease., (Crown Copyright 2010. Published by Elsevier Ltd. All rights reserved.)

Chromatin structure is important for controlling gene expression, but mechanisms underlying chromatin remodeling are not fully understood. Here we report that an FKBP (FK506 binding protein) type immunophilin, AtFKBP53, possesses histone chaperone activity and is required for repressing ribosomal gene expression in Arabidopsis. The AtFKBP53 protein is a multidomain FKBP with a typical peptidylprolyl isomerase (PPIase) domain and several highly charged domains. Using nucleosome assembly assays, we showed that AtFKBP53 has histone chaperone activity and the charged acidic domains are sufficient for the activity. We show that AtFKBP53 interacts with histone H3 through the acidic domains, whereas the PPIase domain is dispensable for histone chaperone activity or histone binding. Ribosomal RNA gene (18S rDNA) is overexpressed when AtFKBP53 activity is reduced or eliminated in Arabidopsis plants. Chromatin immunoprecipitation assay showed that AtFKBP53 is associated with the 18S rDNA gene chromatin, implicating that AtFKBP53 represses rRNA genes at the chromatin level. This study identifies a new histone chaperone in plants that functions in chromatin remodeling and regulation of transcription.

Deregulation of muscle mitochondrial biogenesis may explain the altered mitochondrial properties associated with aging. Maintenance of the mitochondrial network requires the continuous incorporation of nascent proteins into their subcompartments via the protein import pathway. We examined whether this pathway was impaired in muscle of aged animals, focusing on the subsarcolemmal and intermyofibrillar mitochondrial populations. Our results indicate that the import of proteins into the mitochondrial matrix was unaltered with age. Interestingly, import assays supplemented with the cytosolic fraction illustrated an attenuation of protein import, and this effect was similar between age groups. We observed a 2.5-fold increase in protein degradation in the presence of the cytosolic fraction obtained from aged animals. Thus, the reduction of mitochondrial content and/or function observed with aging may not rely on altered activity of the import pathway but rather on the availability of preproteins that are susceptible to elevated rates of degradation by cytosolic factors.

Molecular chaperones of the heat shock proteins (HSP) family are important in numerous cellular processes. In this study, the expression of Hsp60 and Grp78 proteins was investigated in the male reproductive tract. The cellular distribution of Hsp60 and Grp78 proteins was analysed in the human testis and epididymis by immunohistochemical approaches. DNA microarray technology was used to analyse HSP60 and GRP78 gene expression along human epididymis. The cellular localization of these chaperone proteins in ejaculated spermatozoa was investigated by indirect immunofluorescence and by Western blot following sperm sub-cellular fractionation. In the human testis, Hsp60 was detected in spermatogonia, whereas a strong Grp78 staining was observed in spermatocytes and round spermatids. Grp78 protein was also observed in the epididymal epithelium, whereas no Hsp60 staining was observed in this organ by immunohistochemistry. The presence of both Hsp60 and Grp78 RNA in human epididymis was confirmed by microarrays. In ejaculated spermatozoa, Hsp60 was localized in the mid-piece, whereas Grp78 was detected in the neck region. These results indicate that in addition to being expressed in human testis spermatogenic cells, both Hsp60 and Grp78 proteins persist in ejaculated spermatozoa. These findings are in agreement with the involvement of Hsp60 and Grp78 during spermatogenesis and in sperm functions such as fertilization.

Copper chaperone for Cu, Zn superoxide dismutase (CCS) has been shown to be reflective of Cu status in mice and rats. The objective of this study was to evaluate liver and erythrocyte CCS as an indicator of Cu status in beef cattle (Exp. 1), and to test the acute-phase properties of CCS under conditions of inflammation (Exp. 2). In Exp. 1, samples of whole blood and liver were collected at slaughter (492 d of age) from 15 Cu-deficient and 6 Cu-adequate Angus calves. At the time of tissue collection, severe Cu deficiency had been achieved and differences (P < 0.0001) in plasma and liver Cu among Cu-adequate and Cu-deficient calves were extreme (1.26 vs. 0.19 mg/L and 208.4 vs. 6.3 mg/kg for plasma and liver Cu, respectively). Protein levels of CCS were greater in liver (40%; P = 0.02) and erythrocytes (65%; P < 0.0001) of Cu-deficient vs. Cu-adequate calves. In Exp. 2, inflammatory responses were elicited in beef heifers by administration of a Mannheimia hemolytica vaccine. Four days after vaccination, plasma concentrations of the Cu-dependent protein ceruloplasmin and the Cu-independent protein haptoglobin were increased (P < 0.001) by 71 and 83%, respectively. In contrast, detection of CCS protein in samples of liver and erythrocytes did not differ (P >or= 0.45) between baseline (d 0) and d 4 after vaccination. These data demonstrate that bovine erythrocyte and liver CCS protein levels increase in Cu-deficient cattle. Furthermore, levels of CCS protein do not change after a vaccine-induced inflammatory response, suggesting that unlike ceruloplasmin, CCS may be a reliable indicator of Cu status in cattle.

A primary cilium, a sensory organelle present in almost every vertebrate cell, is regularly described in odontoblasts, projecting from the surfaces of the cells. Based on the hypothesis that the primary cilium is crucial both for dentin formation and possibly in tooth pain transmission, we have investigated the expression and localization of the main cilium components and involvement of the OFD1 gene in tooth morphogenesis. Odontoblasts in vitro express tubulin, inversin, rootletin, OFD1, BBS4, BBS6, ALMS1, KIF3A, PC1, and PC2. In vivo, cilia are aligned parallel to the dentin walls, with the top part oriented toward the pulp core. Close relationships between cilium and nerve fibers are evidenced. Calcium channels are concentrated in the vicinity of the basal body. Analysis of these data suggests a putative role of cilia in sensing the microenvironment, probably related to dentin secretion. This hypothesis is enhanced by the huge defects observed on molars from Ofd1 knockout mice, showing undifferentiated dentin-forming cells.

Mycobacterium tuberculosis, the causative agent of tuberculosis, initially contacts host cells with elements of its outer cell wall, or capsule. We have shown that capsular material from the surface of M. tuberculosis competitively inhibits the nonopsonic binding of whole M. tuberculosis bacilli to macrophages in a dose-dependent manner that is not acting through a global inhibition of macrophage binding. We have further demonstrated that isolated M. tuberculosis capsular proteins mediate a major part of this inhibition. Two-dimensional polyacrylamide gel electrophoresis analysis of the capsular proteins showed the presence of a wide variety of protein species, including proportionately high levels of the Cpn60.2 (Hsp65, GroEL2) and DnaK (Hsp70) molecular chaperones. Both of these proteins were subsequently detected on the bacterial surface. To determine whether these molecular chaperones play a role in bacterial binding, recombinant Cpn60.2 and DnaK were tested for their ability to inhibit the association of M. tuberculosis bacilli with macrophages. We found that recombinant Cpn60.2 can inhibit approximately 57% of bacterial association with macrophages, while DnaK was not inhibitory at comparable concentrations. Additionally, when polyclonal F(ab')(2) fragments of anti-Cpn60.2 and anti-DnaK were used to mask the surface presentation of these molecular chaperones, a binding reduction of approximately 34% was seen for anti-Cpn60.2 F(ab')(2), while anti-DnaK F(ab')(2) did not significantly reduce bacterial association with macrophages. Thus, our findings suggest that while M. tuberculosis displays both surface-associated Cpn60.2 and DnaK, only Cpn60.2 demonstrates adhesin functionality with regard to macrophage interaction.

J-domain containing co-chaperone Mrj (mammalian relative to DnaJ) has been implicated in diverse cellular functions including placental development and inhibition of Huntingtin mediated cytotoxicity. It has also been shown to interact with keratin intermediate filaments. Since keratins undergo extensive reorganization during cell division, its interactor Mrj might also play an important role in the regulation of cell cycle. In support of this hypothesis, we report the up-regulation of Mrj protein in M-phase of HeLa cells implicating its role in mitosis related activities. The protein is dispersed throughout the cell during late mitosis and is localized in nucleolus during interphase, confirming that the activity of Mrj is regulated by its cell cycle specific expression together with its differential subcellular localization.

Background: Expansion of the CAG repeat of the TATA-box binding protein (TBP) gene has been identified as the causative mutations in spinocerebellar ataxia 17 (SCA17). TBP is ubiquitously expressed in both central nervous system and peripheral tissues. The underlying molecular changes of SCA17 are rarely explored., Methods: To study the molecular mechanisms underlying SCA17, we generated stably induced isogenic 293 cells expressing normal TBP-Q(36) and expanded TBP-Q(61) and analyzed the expressed proteins using two-dimensional difference in gel electrophoresis (2D-DIGE), followed by mass spectrometry and immunoblotting., Results: Upon induction with doxycycline, the expanded TBP-Q(61) formed aggregates with significant increase in the cell population at subG1 phase and cleaved caspase-3. Proteomics study identified a total of 16 proteins with expression changes greater than 1.5 fold. Among the 16 proteins, PARK7, GLRX3, HNRNPA1, GINS1, ENO1, HNRPK and NPM1 are increased, and SERPINA5, HSPA5, VCL, KHSRP, HSPA8, HNRPH1, IMMT, VCP and HNRNPL are decreased in cells expressing TBP-Q(61) compared with those expressing TBP-Q(36). The altered expression of HSPA5, HSPA8 and PARK7 were further validated by 2D and Western immunoblot analyses., Conclusions: The results illustrate the utility of proteomics to identify alterations of proteins which underlie pathogenesis of SCA17, and may serve as potential therapeutic targets.

Many litres of fluids are found outside cells in the human body. These fluids are rich in dissolved proteins that each have a characteristic three dimensional shape, necessary for normal function, which has been attained by the correct folding of their polypeptide chain(s). The structure of these extracellular proteins can be damaged by a variety of environmental stresses (e.g. heat and oxidation) leading to their partial unfolding and aggregation. This in turn can produce toxic soluble aggregates and/or large insoluble protein deposits, either of which can disrupt normal body function (e.g. in Alzheimer's disease and the systemic amyloidoses). A small family of abundant human blood proteins with the ability to inhibit the aggregation and deposition of stressed (partially unfolded) proteins has been discovered. These extracellular chaperones (ECs) form stable, soluble complexes with stressed proteins. It has been proposed that once bound to stressed proteins, ECs guide them to specific cell surface receptors that direct the "cargo" into lysosomes for degradation. Thus ECs and their receptors may be critical parts of a quality control system to protect the body against the deleterious effects of inappropriately aggregating extracellular proteins. This review focuses on the role of extracellular protein aggregation and deposition in disease, what little is known about mechanisms that act to control these processes, and, lastly, potential new targets for drug development. Newly identified potential drug targets include direct inhibition of protein aggregation, and manipulation of the expression levels of ECs and their receptors.

Molecular chaperones are known to be involved in many cellular functions, however, a detailed and comprehensive overview of the interactions between chaperones and their cofactors and substrates is still absent. Systematic analysis of physical TAP-tag based protein-protein interactions of all known 63 chaperones in Saccharomyces cerevisiae has been carried out. These chaperones include seven small heat-shock proteins, three members of the AAA+ family, eight members of the CCT/TRiC complex, six members of the prefoldin/GimC complex, 22 Hsp40s, 1 Hsp60, 14 Hsp70s, and 2 Hsp90s. Our analysis provides a clear distinction between chaperones that are functionally promiscuous and chaperones that are functionally specific. We found that a given protein can interact with up to 25 different chaperones during its lifetime in the cell. The number of interacting chaperones was found to increase with the average number of hydrophobic stretches of length between one and five in a given protein. Importantly, cellular hot spots of chaperone interactions are elucidated. Our data suggest the presence of endogenous multicomponent chaperone modules in the cell.

Purpose: To identify pretherapeutic predictive biomarkers in tumor biopsies of patients with locally advanced esophageal adenocarcinomas treated with neoadjuvant chemotherapy, we used an explorative proteomic approach to correlate pretherapeutic protein expression profiles with tumor response to neoadjuvant chemotherapy., Experimental Design: Thirty-four patients with locally advanced esophageal adenocarcinomas who received neoadjuvant platin/5-fluorouracil-based chemotherapy before surgical resection were enrolled in this study. Response to chemotherapy was determined (a) by the amount of decline of [18F]fluorodeoxyglucose tumor uptake 2 weeks after the start of chemotherapy measured by positron emission tomography and (b) by histopathologic evaluation of tumor regression after surgical resection. Explorative quantitative and qualitative protein expression analysis was done through a quantitative differential protein expression analysis that used dual-isotope radioactive labeling of protein extracts. Selected identified biomarkers were validated by immunohistochemistry and quantitative real time reverse transcription-PCR., Results: Proteomic analysis revealed four cellular stress response-associated proteins [heat-shock protein (HSP) 27, HSP60, glucose-regulated protein (GRP) 94, GRP78] and a number of cytoskeletal proteins whose pretherapeutic abundance was significantly different (P < 0.001) between responders and nonresponders. Immunohistochemistry and gene expression analysis confirmed these data, showing a significant association between low HSP27 expression and nonresponse to neoadjuvant chemotherapy (P = 0.049 and P = 0.032, respectively)., Conclusions: Albeit preliminary, our encouraging data suggest that protein expression profiling may distinguish cancers with a different response to chemotherapy. Our results suggest that response to chemotherapy may be related to a different activation of stress response and inflammatory biology in general. Moreover, the potential of HSPs and GRPs as biomarkers of chemotherapy response warrants further validation.

Heat shock proteins represent the major elements of the cellular stress response that protects cells from diseases caused by protein misfolding. Small-molecule amplifiers of heat shock proteins have shown promising results in several animal models, demonstrating the potential importance of such compounds for therapeutics. The expression of many heat shock proteins is controlled by HSF1, which forms stress granules in the nucleus when transcriptionally activated. Activation of the cellular stress also correlates with the translocation of HSP70 into nucleoli. The authors have developed an image-based, multiparametric assay to simultaneously monitor the effects of compounds on HSF1/HSP70 stress granule formation in heat-shocked Hela cells. High-content screening of the compound library was performed with a Z' of 0.62, demonstrating a highly robust assay for large-scale screening. The resulting hits showed prolonged amplification of HSP70 induction in heat-stressed cells but no effects in cells without stress. Treatment of cells with selected hits exhibited significant cytoprotection from both oxygen glucose deprivation and rotenone-induced stresses. Thus, high-content screening of HSF1/HSP70 amplifiers provides a practical opportunity for clinical therapeutics targeting protein misfolding diseases.

Endoplasmic reticulum stress has been suggested to play a crucial role in the pathogenesis of diabetic complications. However, whether it is involved in the renal injury of diabetic nephropathy is still not known. We investigated the involvement of ER-associated apoptosis in kidney disease of streptozocin (STZ)-induced diabetic rats. We used albuminuria examination, hematoxylin & eosin (H&E) staining and TUNEL analysis to identify the existence of diabetic nephropathy and enhanced apoptosis. We performed immunohistochemistry, Western blot, and real-time PCR to analyze indicators of ER molecule chaperone and ER-associated apoptosis. GRP78, the ER chaperone, was up-regulated significantly in diabetic kidney compared to control. Furthermore, three hallmarks of ER-associated apoptosis, C/EBP homologous protein (CHOP), c-JUN NH2-terminal kinase (JNK) and caspase-12, were found to have activated in the diabetic kidney. Taken together, those results suggested that apoptosis induced by ER stress occurred in diabetic kidney, which may contribute to the development of diabetic nephropathy.

Microchip-based systems have many desirable characteristics and can be used in much cellular biochemical analysis. Glucose-regulated protein 78 (GRP78), an endoplasmic reticulum chaperone, has a critical role in chemotherapy resistance of some cancers. This work aimed at analyzing the correlation between the expression of GRP78 and an anticancer drug, topoisomerase II inhibitor-VP-16, in human lung cancer cell line NCI-H460 using this microchip-based system. The cells were cultured on a PDMS chip, the expression of GRP78 at both protein and mRNA levels for the cells under the condition with or without the induction of A23187 were assayed by immunofluorescence and chip electrophoresis, respectively. Then the cells were treated by VP-16, percentages of apoptosis and the cycle distributions of the cells were detected by flow cytometry. The cells cultured on the PDMS attached and spread well to micro-channels with high viability. Compared with the non-induced cells, the expression of GRP78 at both protein and mRNA levels for the A23187-induced cells were increased greatly. After treatment by VP-16, the percentage of apoptotic cells decreased nearly threefold for the A23187-induced cells in contrast to the non-induced cells (13.15 +/- 3.84% versus 34.03 +/- 11.45%), and the cells distributed in S phase reduced dramatically (11.96 +/- 1.27% versus 20.76 +/- 3.05%) whereas in G(1) phase increased greatly (74.16 +/- 0.95% versus 57.06 +/- 4%). GRP78 is correlated to the resistance to VP-16 in human lung cancer cell line. The microchip-based system has the potential application and feasibility for cell culture and its functional research.

Time series profiling is a powerful approach for obtaining information on protein expression dynamics and prevailing biochemical pathways. To date, such information could only be obtained at the mRNA level using mature and highly parallel technologies such as microarray gene expression profiling. The generation of time series data at the protein level has lagged due to the lack of robust and highly reproducible methodologies. Using a combination of SILAC strategy, SDS-PAGE and LC-MS/MS, we demonstrate successful monitoring of expression levels of the same set of proteins across different time points within the ER compartment of human primary fibroblast cells when exposed to ER stress inducers tunicamycin and thapsigargin. Data visualization was facilitated using GeneSpring GX analysis platform that was designed to process Affymetrix microarray data. This software also facilitated the generation of important parameters such as data normalization, calculation of statistical values to extract significant changes in protein expression, and the cross comparison of data sets.

Microtubules (MTs) play crucial roles in a variety of cell functions, such as mitosis, vesicle transport and cell motility. MTs also compose specialized structures, such as centrosomes, spindles and cilia. However, molecular mechanisms of these MT-based functions and structures are not fully understood. Here, we analyzed MT co-sedimented proteins from rat brain by tandem mass spectrometry (MS) upon ion exchange column chromatography. We identified a total of 391 proteins. These proteins were grouped into 12 categories: 57 MT cytoskeletal proteins, including MT-associated proteins (MAPs) and motor proteins; 66 other cytoskeletal proteins; 4 centrosomal proteins; 10 chaperons; 5 Golgi proteins; 7 mitochondrial proteins; 62 nucleic acid-binding proteins; 14 nuclear proteins; 13 ribosomal proteins; 28 vesicle transport proteins; 83 proteins with diverse function and/or localization; and 42 uncharacterized proteins. Of these uncharacterized proteins, six proteins were expressed in cultured cells, resulting in the identification of three novel components of centrosomes and cilia. Our present method is not specific for MAPs, but is useful for identifying low abundant novel MAPs and components of MT-based structures. Our analysis provides an extensive list of potential candidates for future study of the molecular mechanisms of MT-based functions and structures.

Activation of endoplasmic reticulum (ER) stress-related cell signals has been reported in several neurologic disorders and may contribute to neurodegeneration. Endoplasmic reticulum stress is also linked to ischemic injury. However, activation of an ER stress response has not been investigated in multiple sclerosis (MS) lesions. We detected increased expression of ER stress-associated C/EBP homologous protein, immunoglobulin heavy chain-binding protein, and X-box-binding protein 1 in multiple cell types, including oligodendrocytes, astrocytes, T cells, and microglia in active MS lesions. Semiquantitative analysis of expression in active, chronic active, and chronic inactive lesions indicated that levels of immunoglobulin heavy chain-binding protein were significantly higher in acute lesions than in non-MS controls or MS normal-appearing white matter, and that ER stress-associated C/EBP homologous protein was upregulated to the greatest extent at the edges of chronic active lesions. Because demyelination may be triggered by a tissue response to ischemia-like conditions, changes in the hypoxia-related antigen D-110 were also investigated, and it was found that increased ER stress-associated C/EBP homologous protein expression can occur in either the presence or absence of D-110. A possible link between a perturbed ER and lesion development in MS suggests a signaling pathway that may represent a new therapeutic target in MS.

Msj-1 gene encodes a DnaJ protein highly expressed in spermatids and spermatozoa of both rodents and amphibians, possibly involved in vesicle fusion and protein quality control by means of interaction with heat shock proteins. We isolated and characterized the entire murine msj-1 gene and searched for putative msj-1-like genes into the human genome. Furthermore, ultrastructural localization of MSJ-1 was analyzed in mouse germ cells by immunogold electron microscopy. The analysis of murine msj-1 genomic sequence reveals that it is an intron less gene. Putative promoter region was predicted within the 600 bp upstream the transcription start site. In mouse, msj-1 maps on chromosome 1, into an intronic region of UDP glucuronosyl-transferase 1 family cluster. At ultrastructural level, MSJ-1 marks the developing acrosomic vesicle and the sperm centriolar region. A blast search against the human genome database revealed two closed regions (Ha and Hb) on human chromosome 2 having high nucleotide identity with murine msj-1 coding region. Similarly to mouse, in human both regions map into an intronic region of UDP glycosyl-transferase 1 family polypeptide A cluster (ugt1a@). A significant ORF encoding a putative DnaJ protein of 145 aa was predicted from Ha. Finally, expression analysis, conducted by RT-PCR in human sperm cells, demonstrated that Ha mRNA is effectively present in humans; by Western blot, a specific MSJ-1 band of approximately 30kDa was detected in human sperm. Taken together, these data suggest that msj-1 gene might be conserved among vertebrates and might exert fundamental functions in reproduction.

Background: Idiopathic adult-onset primary dystonia usually affects the upper body and remains focal. Underlying mechanisms are unknown, and there are only limited neuropathologic studies in the literature. Recently, ubiquitinated perinuclear inclusion bodies were found in the brainstem of patients with DYT1-related dystonia. In X-linked recessive dystonia-parkinsonism, neuronal loss in the striosome compartment of the striatum has been described. However, it was unclear whether these changes are characteristic of these particular disorders or an epiphenomenon of dystonic conditions in general., Methods: Six cases of adult-onset dystonia and four controls were studied using immunohistochemistry to determine the presence of inclusion bodies immunoreactive for torsinA, ubiquitin, and laminA/C in the brainstem. The distribution of calcineurin expressing neurons in the striatum was also determined to ascertain whether there is loss of neurons in the striosome compartment., Results: In contrast to early-onset dystonia, neuronal inclusions immunoreactive for torsinA, ubiquitin, and laminA/C were not present in the brainstem nuclei. There was no apparent loss of the striatal striosome compartment., Conclusion: Our findings suggest that the underlying mechanism in the adult-onset primary torsion dystonia is different from that of early-onset DYT1-related dystonia and also DYT3 X-linked recessive dystonia-parkinsonism. Alternative mechanisms may underpin the pathophysiology of adult-onset primary dystonia.

Prefoldin is a hetero-hexameric ATP-independent chaperone, shared by eukaryotes and archaea, which binds non-native proteins preventing them from aggregation. We report the identification and characterization in vivo and in vitro of the first prefoldin from a crenarchaeon, the hyperthermophile Sulfolobus solfataricus. A functional complex was obtained either co-expressing the alpha- and beta-prefoldin subunits in Escherichia coli, or incubating at high temperature the separately expressed subunits. In S. solfataricus, prefoldin expression and apparent molecular weight were not affected by either heat or cold shock.

AtTic40 is part of the chloroplastic protein import apparatus that is anchored in the inner envelope membrane by a single N-terminal transmembrane domain, and has a topology in which the bulk of the C-terminal domain is oriented toward the stroma. The targeting of AtTic40 to the inner envelope membrane involves two steps. Using an in vitro import assay, we showed that the sorting of AtTic40 requires a bipartite transit peptide, which was first cleaved by the stromal processing peptidase (SPP), thus generating a soluble AtTic40 stromal intermediate (iAtTic40). iAtTic40 was further processed by a second unknown peptidase, which generates its mature form (mAtTic40). Using deletion mutants, we identified a sequence motif N-terminal of the transmembrane domain that was essential for reinsertion of iAtTic40 into the inner envelope membrane. We have designated this region a serine/proline-rich (S/P-rich) domain and present a model describing its role in the targeting of AtTic40 to the inner envelope membrane.

High mobility group A (HMGA) proteins (HMGA1a, HMGA1b, HMGA1c and HMGA2) are nonhistone chromosomal proteins that do not have transcriptional activity per se, but they orchestrate the assembly of multiprotein complexes involved in gene transcription, replication and chromatin structure through a complex network of protein-DNA and protein-protein interactions. To better understand their mechanisms of action, we have used a combination of coimmunoprecipitation, 1-D gel SDS-PAGE and MS to identify new potential molecular interactors. We have found 11 proteins that associate with HMGA1. These proteins belong to three different classes: mRNA processing proteins, RNA helicases and protein chaperones. Some interactions were confirmed by coimmunoprecipitation and pull-down experiments in human embryonal kidney 293 cells. These experimental data suggest that HMGA1 proteins can associate with proteins that are strictly involved in chromatin structure and in several important mRNA processing steps, supporting the idea that HMGA1 proteins can also participate in these events.

Nontypeable Haemophilus influenzae (NTHi) is an important cause of illness among children. To further understand the role of laterally transferred genes in NTHi colonization and otitis media, the prevalence of hicAB, lav, tnaA, and hifBC was determined among 44 middle ear and 35 throat NTHi isolates by dot-blot hybridization.

Background: High-fat enteral nutrition reduces the inflammatory response following hemorrhagic shock in the rat., Aims: We hypothesized that this intervention might also ameliorate the remote organ injury to the liver associated with this model., Methods: Male Sprague-Dawley rats were either starved or fed low-fat or high-fat isocaloric isonitrogenous feed prior to nonlethal hemorrhagic shock induced by a 40% reduction in the blood volume. Animals were sacrificed at 90 minutes or 24 hours after injury. Liver cell damage was assessed by histology and long polymerase chain reaction (PCR) to detect mitochondrial DNA damage. Stress protein expression was measured by Western blot and mRNA expression by real-time PCR and immunohistochemistry., Results: Animals fed a low-fat diet had the same severity of liver injury as starved animals and increased expression of stress proteins. Animals fed a high-fat diet had minimal liver injury, no evidence of mitochondrial DNA damage, and significantly lower expression of stress proteins. This effect is associated with preservation of hepatocellular morphology, attenuation of mitochondrial DNA damage, and a reduced stress protein response to injury., Conclusions: High-fat enteral nutrition protects the liver from the remote effects of hemorrhagic shock, but the mechanism of this effect is not yet known.

Chaperone proteins are effective antitumor vaccines when purified from a tumor source, some of which are in clinical trials. Such vaccines culminate in tumor-specific T cell responses, implicating the role of adaptive immunity. We have developed a rapid and efficient procedure utilizing an isoelectric focusing technique to obtain vaccines from tumor or normal tissues called chaperone-rich cell lysate (CRCL). Tumor-associated peptides, the currency of T cell-mediated anticancer immunity, are believed to be purveyed by chaperone vaccines. Our purpose was to demonstrate our ability to manipulate the peptide antigen repertoire of CRCL vaccines as a novel anticancer strategy. Our methods allow us to prepare "designer" CRCL, utilizing the immunostimulation activity and the carrying capacity of CRCL to quantitatively acquire and deliver exogenous antigenic peptides (e.g., derived from the oncogenic BCR/ABL protein in chronic myelogenous leukemia). Using fluorescence-based and antigen-presentation assays, we determined that significant quantities of exogenously added peptide could accumulate in "designer" CRCL and could stimulate T cell activation. Further, we concluded that peptide-embedded CRCL, devoid of other antigens, could generate potent immunity against pre-established murine leukemia. Designer CRCL allows for the development of personalized vaccines against cancers expressing known antigens, by embedding antigens into CRCL derived from normal tissue.

Periodontitis is an inflammatory disease initiated by host-parasite interactions which contributes to connective tissue destruction and alveolar bone resorption. Porphyromonas gingivalis (P.g.), a black-pigmented Gram-negative anaerobic bacterium, is a major pathogen in the development and progression of periodontitis. To characterize the role that P. gingivalis and its cell surface components play in disease processes, we investigated the differential expression of proteins induced by live P.g., P.g. LPS, and P.g. FimA, using two-dimensional gel electrophoresis in combination with mass spectrometry. We have tested whether, at the level of protein expression, unique signaling pathways are differentially induced by the bacterial components P.g. LPS and P.g. FimA, as compared to live P.g. We found that P.g. LPS stimulation of THP-1 up-regulated the expression of a set of proteins compared to control: deoxyribonuclease, actin, carbonic anhydrase 2, alpha enolase, adenylyl cyclase-associated protein (CAP1), protein disulfide isomerase (PDI), glucose regulated protein (grp78), and 70-kDa heat shock protein (HSP70), whereas FimA treatment did not result in statistically significant changes to protein levels versus the control. Live P.g. stimulation resulted in 12 differentially expressed proteins: CAP1, tubulin beta-2 chain, ATP synthase beta chain, tubulin alpha-6 chain, PDI, vimentin, 60-kDa heat shock protein, and nucleolin were found to be up-regulated, while carbonic anhydrase II, beta-actin, and HSP70 were down-regulated relative to control. These differential changes by the bacteria and its components are interpreted as preferential signal pathway activation in host immune/inflammatory responses to P.g. infection.

Objective: To identify epitopes on Escherichia coli heat-shock protein (HSP) dnaJ or on homologous human HSP dnaJ involved in the induction/modulation of autoimmune inflammation in patients with oligoarticular juvenile idiopathic arthritis (JIA)., Methods: We used a proliferation assay and cytokine production to evaluate the immune responses of synovial fluid mononuclear cells (SFMCs) to pan-HLA-DR binder peptides derived from either homologous or nonhomologous regions on bacterial and human HSP dnaJ. Cytofluorometric analysis was performed in order to phenotype and sort Treg cells. Sorted cells were then analyzed for the expression of the forkhead box P3 (FoxP3) transcription factor, and their regulatory capacity was tested in coculture assays., Results: T cell responses to E coli HSP dnaJ-derived peptides were eminently proinflammatory. Conversely, peptides derived from human HSP dnaJ induced interleukin-10 (IL-10) production from SFMCs of patients with oligoarticular JIA. A positive correlation was found between disease with a better prognosis (persistent oligoarticular JIA) and recognition of 3 human HSP dnaJ-derived peptides. The recognition of the human peptide H134-148 also induced a significantly greater amount of IL-10 in patients with persistent oligoarticular JIA than in those with extended oligoarticular JIA (P = 0.0012). Incubation of SFMCs from patients with persistent oligoarticular JIA with this human epitope increased the percentage of Treg cells and FoxP3 expression. It also induced the recovery of suppressor activity by Treg cells., Conclusion: This is the first description of a self-regulating immune modulator circuit active during autoimmune inflammation through recognition of HSP epitopes with different functional properties. These epitopes induce T cells with regulatory function. Such induction correlates with disease severity and prognosis.

In type-1 diabetes mellitus (T1DM) with diabetic nephropathy (DN), accumulation of abnormal proteins in the kidney and other tissues may derive from constitutive alterations of intracellular protein recognition, assembly, and turnover. We characterized the proteins involved in these functions in cultured skin fibroblasts from long-term T1DM patients with [DN+] or without [DN-] nephropathy but similar metabolic control, and from matched healthy subjects. 2-D gel electrophoresis and MS-MALDI analysis were employed. The [DN+] T1DM patients, compared with the two other groups, exhibited increased abundance of a high-molecular weight isoform of protein disulphide-isomerase A3 and a decrease of two low-molecular weight isoforms. They also had increased levels of heat shock protein (HSP) 60 kDa isoform #A4, of HSP71 kDa isoform #A30, and of HSP27 kDa isoform #6, whereas the HSP27 kDa isoforms #A90 and #A71 were decreased. Cathepsin beta-2 (#40), the cation-independent mannose 6-phosphate receptor binding protein 1 (CIMPR) (#A27), and annexin 2 (#A9) were also decreased in the [DN+] T1DM patients, whereas the RNA-binding protein regulatory subunity (#38) and the translationally-controlled tumor protein (TCTP) (#A45) were increased. These changes of chaperone-like proteins in fibroblasts may highlight those of the kidney and be patho-physiologically related to the development of nephropathy in T1DM.

Genes at the centromeric end of the human leukocyte antigen region influence adaptive autoimmune diseases and cancer. In this study, we characterized protein expression of HKE2, a gene located in the centromeric portion of the class II region of the major histocompatibility complex encoding subunit 6 of prefoldin. Immunohistochemical analysis using an anti-HKE2 antibody indicated that HKE2 protein expression is dramatically upregulated as a consequence of activation. In a tissue microarray and in several tumors, HKE2 was overexpressed in certain cancers compared with normal counterparts. The localization of the HKE2 gene to the class II region, its cytoplasmic expression and putative protein-binding domain suggest that HKE2 may function in adaptive immunity and cancer.

In human reproduction, hyperhomocysteinemia has been reported as a risk factor for early pregnancy loss and congenital birth defects. Hyperhomocysteinemia is also recognized as a cause of maternal obstetric complications such as preeclampsia. The role of plasma hyperhomocysteinemia in female fertility was examined using cystathionine beta synthase knockout (cbs KO) mice. Cbs KO females were infertile, showed alterations in the estrus cycle and an increased progesterone response during pseudo-pregnancy induction. Both cbs KO ovaries and ovulated oocytes showed no major morphological alterations. However, placental and uterine masses were decreased at day 18 of pregnancy and showed morphological abnormalities. In cbs-KO pregnant females, the number of uterine implantation sites was not decreased despite the low number of surviving embryos. Fertility was restored when cbs-deficient ovaries were transplanted to normal ovarectomized recipients. We detected an increased uterine expression of Grp78, a marker of endoplasmic reticulum stress, which was accompanied by the decreased levels of uterine cbs mRNA in both hyperhomocysteinemic heterozygous (fertile) and homozygous (non-fertile) females. Our results indicate that cbs -/- female infertility is a consequence of the uterine failure and demonstrate that uterine endoplasmic reticulum stress and cbs expression are not determinant of infertility, suggesting that uterine dysfunction is a consequence of either hyperhomocysteinemia or other factor(s) in the uterine environment of cbs -/- animals. In summary, these studies demonstrate the potential importance of homocysteine levels for uterine handling of embryos.