Proteomics-driven progress in neurodegeneration research

Proteomics technologies have been widely used in the investigation of neurodegenerative and psychiatric disorders, and in particular in the detection of differences between healthy individuals and patients suffering from such diseases. Thus, brain and cerebrospinal fluid (CSF) samples from patients with Alzheimer's disease, Down syndrome, Pick's disease, Parkinson's disease, schizophrenia, and other disorders as well as brain and CSF from animals serving as models of neurological disorders have been analyzed by proteomics. 2-DE followed by MALDI-TOF-MS has been mainly applied as this proteomics approach provides the possibility of convenient quantification of protein levels and detection of post-translational modifications. About 330 unique proteins with deranged levels and modifications have been detected by proteomics approaches to be related to neurodegeneration and psychiatric disorders. They are mainly involved in metabolism pathways, cytoskeleton formation, signal transduction, guidance, detoxification, transport, and conformational changes. In this article, we provide a summary of the major contributions of proteomics technologies in the study of neurodegenerative and psychiatric diseases, in particular, in the detection of changes in protein levels and modifications related to these disorders.

Proteomic analysis of the heat shock response in Synechocystis PCC6803 and a thermally tolerant knockout strain lacking the histidine kinase 34 gene

Proteomic analysis of the heat shock response of wild type and a mutant of the histidine kinase 34 gene (Deltahik34), which shows increased thermal tolerance, has been performed in the cyanobacterium Synechocystis sp. PCC6803. In vivo radioactive labelling demonstrates that major proteomic changes occur within 1 h of heat shock. 2-D DIGE and MS have been used to quantify changes in specific proteins following heat shock in the wild type and the mutant. Over 100 spots, corresponding to 65 different proteins alter following heat shock. Changes occur not only in the classical heat shock proteins but also in the protein biosynthetic machinery, amino acid biosynthetic enzymes, components of the light and dark acts of photosynthesis and energy metabolism. The Deltahik34 cells have elevated levels of heat shock proteins under both non-heat shock and heat shock conditions, in comparison to the wild type, consistent with Hik34, or a down stream component, being a negative regulator of heat shock-responsive genes.

The unfolded protein response affects neuronal cell cycle protein expression: implications for Alzheimer's disease pathogenesis

Alzheimer's disease (AD) is characterized by the accumulation and aggregation of misfolded proteins. The presence of misfolded proteins in the endoplasmic reticulum (ER) triggers a cellular stress response called the unfolded protein response (UPR). Previously, we have shown that the UPR is activated in AD neurons. In actively dividing cells, activation of the UPR is accompanied by decreased cell cycle protein expression and an arrest in the G1 phase of the cell cycle. Aberrant expression of cell cycle proteins has been observed in post mitotic neurons in AD and is suggested to be involved in neurodegeneration. In this study we show that the protein levels of BiP/GRP78, an ER-stress marker, is increased in Braak stages B and C for amyloid deposits. This is in contrast to the levels of cell cycle markers cyclin D1, cyclin E and phosphorylated retinoblastoma protein (ppRb) which are decreased in Braak stage C compared to Braak stage A for amyloid deposits. In addition, we report a negative correlation between neuronal expression of ppRb and expression levels of BiP/GRP78 in control and AD cases. Activation of the UPR in neuronal cells induces changes in cell cycle protein expression similar to these observed in AD brain. ER stress inducers tunicamycin and thapsigargin down-regulate cell cycle proteins ppRb and cyclin D1 in differentiated neuroblastoma cells. In contrast, protein levels of p27, a cyclin dependent kinase inhibitor, are increased after induction of ER-stress using tunicamycin. These data suggest that activation of the UPR affects cell cycle protein expression in neurons during neurodegeneration in AD.

Proteomic identification of a stress protein, mortalin/mthsp70/GRP75: relevance to Parkinson disease

Functional impairment of mitochondria and proteasomes and increased oxidative damage comprise the main pathological phenotypes of Parkinson disease (PD). Using an unbiased quantitative proteomic approach, we compared nigral mitochondrial proteins of PD patients with those from age-matched controls. 119 of 842 identified proteins displayed significant differences in their relative abundance (increase/decrease) between the two groups. We confirmed that one of these, mortalin (mthsp70/GRP75, a mitochondrial stress protein), is substantially decreased in PD brains as well as in a cellular model of PD. In addition, nine candidate mortalin-binding partners were identified as potential mediators of PD pathology. Manipulations of mortalin level in dopaminergic neurons resulted in significant changes in sensitivity to PD phenotypes via pathways involving mitochondrial and proteasomal function as well as oxidative stress.

A proteome reference map and proteomic analysis of Bifidobacterium longum NCC2705

A comprehensive proteomic study was carried out to identify and characterize proteins expressed by Bifidobacterium longum NCC2705. A total of 708 spots representing 369 protein entries were identified by MALDI-TOF-MS and/or ESI-MS/MS. Isoelectric point values estimated by gel electrophoresis matched closely with their predicted ones, although some discrepancies exist suggesting that post-translational protein modifications might be common in B. longum. The identified proteins represent 21.4% of the predicted 1727 ORFs in the genome and correspond to 30% of the predicted proteome. Moreover 95 hypothetical proteins were experimentally identified. This is the first compilation of a proteomic reference map for the important probiotic organism B. longum NCC2705. The study aimed to define a number of cellular pathways related to important physiological processes at the proteomic level. Proteomic comparison of glucose- and fructose-grown cells revealed that fructose and glucose are catabolized via the same degradation pathway. Interestingly the sugar-binding protein specific to fructose (BL0033) and Frk showed higher levels of expression in cells grown on fructose than on glucose as determined by semiquantitative RT-PCR. BL0033 time course and concentration experiments showed that the induction time and fructose concentration correlates to increased expression of BL0033. At the same time, an ABC (ATP-binding cassette) transporter ATP-binding protein (BL0034) was slightly up-regulated in cells grown on fructose compared with glucose. All of the above results suggest that the uptake of fructose into the cell may be conducted by a specific transport system in which BL0033 might play an important role.

Cis-hydroxyproline-induced inhibition of pancreatic cancer cell growth is mediated by endoplasmic reticulum stress

AIM: To investigate the biological effects of cis-hydroxyproline (CHP) on the rat pancreatic carcinoma cell line DSL6A, and to examine the underlying molecular mechanisms.

METHODS: The effect of CHP on DSL6A cell proliferation was assessed by using BrdU incorporation. The expression of focal adhesion kinase (FAK) was characterized by Western blotting and immunofluorescence. Induction of endoplasmic reticulum (ER) stress was investigated by using RT-PCR and Western blotting for the glucose-related protein-78 (GRP78) and growth arrest and DNA inducible gene (GADD153). Cell viability was determined through measuring the metabolic activity based on the reduction potential of DSL6A cells. Apoptosis was analyzed by detection of caspase-3 activation and cleavage of poly(ADP-ribose) polymerase (PARP) as well as DNA laddering.

RESULTS: In addition to inhibition of proliferation, incubation with CHP induced proteolytic cleavage of FAK and a delocalisation of the enzyme from focal adhesions, followed by a loss of cell adherence. Simultaneously, we could show an increased expression of GRP78 and GADD153, indicating a CHP-mediated activation of the ER stress cascade in the DSL6A cell line. Prolonged incubation of DSL6A cells with CHP finally resulted in apoptotic cell death. Beside L-proline, the inhibition of intracellular proteolysis by addition of a broad spectrum protease inhibitor could abolish the effects of CHP on cellular functions and the molecular processes. In contrast, impeding the activity of apoptosis-executing caspases had no influence on CHP-mediated cell damage.

CONCLUSION: Our data suggest that the initiation of ER stress machinery by CHP leads to an activation of intracellular proteolytic processes, including caspase-independent FAK degradation, resulting in damaging pancreatic carcinoma cells.

Resistance training increases heat shock protein levels in skeletal muscle of young and old rats

Heat shock proteins (HSP) HSP72, HSC70 and HSP25 protein levels and mRNA levels of HSP72 genes (Hsp72-1, Hsp72-2, Hsp72-3) and HSC70 were examined in tibialis anterior muscles from young and old rats following 4.5 weeks of heavy resistance exercise. Young (3 months) (n=10) and old (30 months) (n=9) rats were subjected to 14 sessions of electrically evoked resistance training using stretch-shortening contractions of the left limb that activated the dorsiflexor muscle group, including the tibialis anterior muscle, while the right side served as the intra-animal control. Muscle wet weight of the left tibialis anterior increased by 15.6% in young animals compared to the untrained right side, while the aged rats demonstrated no significant hypertrophy based on muscle wet weight. There were no differences in mRNA expression between the control and experimental muscles in either the old or the young animals for any of the four genes examined. On the other hand, HSP72 levels as determined by Western blots were significantly (p<0.01) higher (968.8 and 409.1%) in the trained as compared to the contralateral control muscle in young and old animals, respectively. HSP25 expression was increased significantly (p<0.01) by training in muscles of young rats (943.1%) and old rats (420.3%). Moreover, there was no training by age interaction for HSP72, while a significant age and training by age effects were found in muscles for HSP25. There was no change in HSC70 protein expression in response to the training intervention in either age group. SOD-1 enzyme level increased by 66.6% in the trained muscles of the young rats, while this enzyme was 33% lower in trained muscles compared to the untrained control side in old rats. Moreover, a significant (p<0.05) training by age interaction was found for SOD-1 enzyme levels. This study suggests that fast contracting muscles in young and old animals are capable of increasing HSP expression in response to high intensity contractile stress. Furthermore, the data are consistent with the hypothesis that higher levels of oxidative stress in muscles of old animals limit HSP levels and/or function in response to high intensity contractile stress.

Analytical assays of human HSP27 and thermal-stress survival of Escherichia coli cells that overexpress it

HSP27 is a small heat-shock protein (sHSP). Such proteins are produced in all organisms. These small HSPs exhibit chaperone-like activity that can bind to unfolded polypeptides and prevent uncontrolled protein aggregation in vitro. Cellular anti-apoptosis function and enhanced cell survival are correlated with increased expression of HSPs. This study presents a thermal-stress survival model for cells using the Escherichia coli expression system for which human HSP27, a recombinant protein, is inducible. Results show that E. coli cells overexpressing human HSP27 have enhanced tolerance to 50 degrees C thermal stress.

Visualizing hidden heterogeneity in isogenic populations of C. elegans

Age-specific mortality levels off at advanced ages in many species; one explanation for this phenomenon is provided by the population heterogeneity theory. Although mortality at advanced ages can be well fit by heterogeneity models, population heterogeneity remains theoretical, lacking much direct evidence to support the existence of unobserved heterogeneity. Here, we provide direct evidence to support the heterogeneity theory by using isogenic population of worms of Caenorhabditis elegans. We measure the ability of individual worms to respond to a heat stress using an HSP-16.2 promoter that has been attached to GFP, a fluorescent marker that can be assessed in living animals. Worms differ substantially in their response; worms with high response have a long lifespan, and worms with low response to stress have a short life. Each of these classes results from a mix of two distinct, heterogeneous classes of worms and the addition of more classes does not result in a better fit.

Chronic acid water feeding protects mice against lethal gut-derived sepsis due to Pseudomonas aeruginosa

Acidified feeding formulas have been proposed as a method of controlling gastrointestinal colonization and nosocomial infection in critically ill patients. We examined possible mechanisms by which chronic acid water feeding might protect the host against lethal gut derived sepsis by assessing its effect on both local intestinal epithelial barrier function to bacteria as well as on local and systemic heat shock protein expression. Heat shock protein expression measured by immunoblot demonstrated that HSP25 was increased in the stomach, aorta and kidney of mice chronically fed acid water (8 weeks) compared to tap water fed controls. HSP72 expression was also increased in the aorta of mice drinking acid water. The protein content of cecum and its barrier function were enhanced in mice ingesting acidified water. The direct effect of an acid environment on intestinal epithelial barrier function was tested in cultured human intestinal epithelial cells. An acidified environment protected against bacterial mediated disruption of the intestinal epithelial barrier. Finally, the protective effect of chronic acid water feeding on gut-derived sepsis due to P. aeruginosa was tested in mice. Chronic acid water feeding protected mice from the lethal gut derived sepsis due to P. aeruginosa.

The effect of aging and inflammation on heat shock protein 27 in human monocytes and lymphocytes

Heat shock proteins (Hsp) are highly conserved proteins and their synthesis is ubiquitous in virtually every species in which they have been sought. In the present study we have investigated the effect of age and inflammation on the induction of Hsp27 in human peripheral blood mononuclear cells, using flow cytometry. Sixty-six healthy control subjects or patients suffering from inflammation participated in the study. In both heat shocked (HS) and non-HS conditions, the percentage of Hsp27 producing lymphocytes as well as the intensity of Hsp27 in lymphocytes and monocytes were negatively influenced by age. The basal levels and also the levels of Hsp27 production after HS were higher for monocytes compared to lymphocytes. In addition, we found that HS resulted in a small but significant increase in the levels of Hsp27 in lymphocytes whereas a significant decrease in Hsp27 was noticed for monocytes. In conclusion, results presented herein provide evidence in support of an age-related decrease in the level of Hsp27, which disappeared in the presence of inflammation. Several relationships between the circulating levels of CRP, IL-6 and TNF-alpha with the various Hsp27 determinations were observed, indicating that cytokines are able to influence the production of Hsp27.

Differential proteome analysis of tonsils from children with chronic tonsillitis or with hyperplasia reveals disease-associated protein expression differences

A proteomic approach has been used to establish a proteome map and differentiate between the protein composition of tonsils from patients with chronic tonsillitis (CT) and that of tonsils with hyperplasia (HPL). Two-dimensional gel analysis was performed with material from four patients with HPL and five patients with CT. An average of approximately 600 spots were detected in each gel. A total of 127 different proteins were identified in 158 spots analyzed by mass spectrometry. Our study revealed disease-associated differences between protein abundance for two protein spots, an HSP27 isoform and UMP-CMP kinase. Both protein spots were more abundant in the CT group. HSP27 ELISA was performed for 32 patients, 12 belonging to the HPL group and 20 to the CT group. ELISA could not be used to differentiate HSP27 isoforms nor to distinguish CT from HPL. HSP27 was found to migrate to two further protein spots in the 2D gels. The differently expressed HSP27 isoform migrated as the most acidic of all the HSP27 isoforms detected, indicating the highest degree of phosphorylation. The sum of all three HSP27 abundances in the gels from the CT group was not different from that of the HPL group, consistent with the ELISA results. Our results suggest that phosphorylation differences caused the observed migration differences of HSP27. Together with the UMP-CMP kinase abundance differences, we conclude that kinase and/or phosphatase activity are different in CT and HPL.

Changes in protein synthesis during thermal adaptation of Propionibacterium freudenreichii subsp. shermanii

Dairy propionibacteria are present in Graviera Kritis, a traditional Gruyère-type cheese made without added propionic starter. Ten isolated strains were identified by a combination of SDS-PAGE, species-specific PCR and according to their ability to ferment lactose. They were all found to belong to the Propionibacterium freudenreichii subsp. shermanii species. Because of the stressing Gruyère technology, which includes cooking at 52 to 53 degrees C their thermotolerance was investigated at 55 degrees C. Thermotolerant and thermosensitive strains were clearly discriminated. Interestingly, the reference strain CIP 103027 belongs to the sensitive subset. One sensitive strain, ACA-DC 1305 and one tolerant, ACA-DC 1451, were selected for further study and compared to CIP 103027. For the sensitive strains ACA-DC 1305 and CIP 103027, heat pre-treatment at 42 degrees C conferred thermoprotection of cells at the lethal temperature of 55 degrees C, while there was less effect on the tolerant ACA-DC 1451. No cross-protection of salt-adapted cells against heat stress was observed for none of the strains. Differential proteomic analysis revealed distinct but overlapping cell responses to heat stress between sensitive and tolerant strains. Thermal adaptation upregulated typical HSPs involved in protein repair or turnover in the sensitive one. In the tolerant one, a distinct subset of proteins was overexpressed, whatever the temperature used, in addition to HSPs. This included enzymes involved in propionic fermentation, amino acid metabolism, oxidative stress remediation and nucleotide phosphorylation. These results bring new insights into thermoprotection in propionibacteria and the occurrence of divergent phenotypes within a same subspecies.

Rapid turnover and polyubiquitylation of the retroviral restriction factor TRIM5

TRIM5alpha and TRIMCyp are retroviral restriction factors that, like other members of the tripartite motif (TRIM) family, contain RING, B-box 2 and coiled-coil domains. We found that both proteins are rapidly turned over, with half-lives of 50-60 min. Polyubiquitylation and rapid degradation of TRIM5alpha depended upon intact RING and B-box 2 domains. A chimera consisting of monkey TRIM5alpha with a RING domain of human TRIM21 exhibited a half-life of 210 min, yet potently restricted human immunodeficiency virus; therefore, rapid turnover of TRIM5alpha is not required for its antiretroviral activity. TRIM5alpha forms cytoplasmic bodies that contain other polyubiquitylated proteins, heat shock proteins and dynein, and thus resemble aggresome precursors. Consistent with this interpretation, proteasomal inhibitors triggered the formation of TRIM5alpha(rh)-containing aggresomes in a microtubule-dependent manner. Thus, TRIM5alpha levels in the cell are maintained by continuous synthesis and rapid proteasome-mediated degradation, imbalances in which result in the formation of pre-aggresomal cytoplasmic bodies.

Stress proteins expression in rat kidney and liver chronically exposed to aluminium sulphate

Aluminium (Al) is the third most widespread metal in the environment. It is toxic for the brain, bone and haematological system but unfortunately very little data exist for other organs. Stress proteins are induced or enhanced against metal toxicity with an essential role in the recovery of organules and other cellular proteins. This immunohistochemical study was performed to analyze the distribution of three stress proteins (HSP25, HSP72, GRP75) in rat kidney and liver orally exposed to Al sulphate daily for 3 and 6 months. Al-induced alterations were further studied by histopathology (H-E, PAS, Perl's, Masson) and ultrastructural morphometry. In the kidney: HSP25 was enhanced in proximal tubules after 6 months Al-exposure when abnormal brush borders were observed; HSP72 was induced in proximal tubules only after long Al-treatment; GRP75 was raised in midcortical area sometimes within nuclei. Furthermore, lysosomal and lipofuscins densities increased in the juxtamedullary tubules after 3 months Al exposure with respect to controls. In the liver: Perl's-positive deposits and fibrosis became evident after Al treatment. HSP25 was very weak; HSP72 focal in pericentral hepatocytes at 3 months and induced also in Kupffer cells at 6 months; GRP75 diffuse in periportal hepatocytes and non parenchymal cells at 6 months. Prolonged Al exposure stimulated stress proteins strictly organ-dependently in the rat. Their distribution in kidney and liver seems related to cumulative sublethal effects induced by metal and could be a sensitive index of Al susceptibility of these organs.

Liposome-Doped Nanocomposites as Artificial-Cell-Based Biosensors: Detection of Listeriolysin O

Listeriolysin O (LLO) is a pore-forming hemolysin secreted by the foodborne pathogen Listeria monocytogenes and is required for bacterial virulence. Current detection methods for L. monocytogenes are time-consuming, labor-intensive, and expensive, which is impractical considering the limitations of food storage. To overcome these problems, we developed a liposome-doped silica nanocomposite as a simple, inexpensive, and highly stable biosensor material that mimics existing whole-cell assays for LLO. Small unilamellar liposomes containing fluorescent dyes were immobilized within porous silica using alcohol-free sol-gel synthesis methods. The immobilized liposomes served as cellular surrogates for membrane insertion and pore formation by LLO. The integrity of liposomes in the solid-state sol-gel glass was investigated by fluorescence quenching and leaching assays. The materials were stable for at least 5 months in ambient conditions. Both free and immobilized liposomes responded to LLO at pH 6.0 with concentration dependent kinetics. The pore formation of LLO in liposome-doped silica composites displayed similar kinetic curves as free liposomes but with slower rates. LLO insertion into the immobilized liposomes was pH dependent. No increase in membrane permeability was observed at pH 7.4 for the liposome-doped composites in the presence of LLO. Immobilized liposomes can detect LLO in approximately 1.5 h using a steady state calibration and within 30 min using a kinetic calibration. These liposome silica composites potentially could be used for the detection of hemolysin producing L. monocytogenes as well as the many other bacteria that produce pore-forming toxins.

Heat-shock protein 27 is a major methylglyoxal-modified protein in endothelial cells

In endothelial cells cultured under high glucose conditions, methylglyoxal is the major intracellular precursor in the formation of advanced glycation endproducts. We found that endothelial cells incubated with 30 mM d-glucose produced approximately 2-fold higher levels of methylglyoxal but not 3-deoxyglucosone and glyoxal, as compared to 5 mM d-glucose. Under hyperglycaemic conditions, the methylglyoxal-arginine adduct argpyrimidine as detected with a specific antibody, but not N(e)-(carboxymethyl)lysine and N(e)-(carboxyethyl)lysine, was significantly elevated. The glyoxylase I inhibitor HCCG and the PPARgamma ligand troglitazone also increased argpyrimidine levels. Increased levels of argpyrimidine by glucose, HCCG and troglitazone are accompanied by a decrease in proliferation of endothelial cells. A 27 kDa protein was detected as a major argpyrimidine-modified protein. With in-gel digestion and mass spectrometric analysis, we identified this major protein as heat-shock protein 27 (Hsp27). This argpyrimidine modification of Hsp27 may contribute to changes in endothelial cell function associated to diabetes.

Physiologically relevant increase in temperature causes an increase in intestinal epithelial tight junction permeability

The effects of physiologically relevant increase in temperature (37-41 degrees C) on intestinal epithelial tight junction (TJ) barrier have not been previously studied. Additionally, the role of heat-shock proteins (HSPs) in the regulation of intestinal TJ barrier during heat stress remains unknown. Because heat-induced disturbance of intestinal TJ barrier could lead to endotoxemia and bacterial translocation during physiological thermal stress, the purpose of this study was to investigate the effects of modest, physiologically relevant increases in temperature (37-41 degrees C) on intestinal epithelial TJ barrier and to examine the protective role of HSPs on intestinal TJ barrier. Filter-grown Caco-2 intestinal epithelial cells were used as an in vitro intestinal epithelial model system to assess the effects of heat exposure on intestinal TJ barrier. Exposure of filter-grown Caco-2 monolayers to modest increases in temperatures (37-41 degrees C) resulted in a significant time- and temperature-dependent increases in Caco-2 TJ permeability. Exposure to modest heat (39 or 41 degrees C) resulted in rapid and sustained increases in HSP expression; and inhibition of HSP expression produced a marked increase in heat-induced increase in Caco-2 TJ permeability (P < 0.001). Heat exposure (41 degrees C) resulted in a compensatory increase in Caco-2 occludin protein expression and an increase in junctional localization. Inhibition of HSP expression prevented the compensatory upregulation of occludin protein expression and produced a marked disruption in junctional localization of occludin protein during heat stress. In conclusion, our findings demonstrate for the first time that a modest, physiologically relevant increase in temperature causes an increase in intestinal epithelial TJ permeability. Our data also show that HSPs play an important protective role in preventing the heat-induced disruption of intestinal TJ barrier and suggest that HSP mediated upregulation of occludin expression may be an important mechanism involved in the maintenance of intestinal epithelial TJ barrier function during heat stress.

Odontoblast responses to GaAlAs laser irradiation in rat molars: an experimental study using heat-shock protein-25 immunohistochemistry

Pulpal responses to gallium-aluminum-arsenide (GaAlAs) laser irradiation applied to the tooth remains to be elucidated. This study aimed to evaluate the effect of the GaAlAs laser on odontoblasts using immunohistochemistry for heat-shock protein (HSP)-25, which labels mature and newly differentiated odontoblasts. The mesial surface of the upper right first molar of 8-wk-old Wistar rats was lased at an output power of 0.5-1.5 W for 180 s. The animals were perfusion-fixed at intervals of 6 h to 30 d after irradiation. At 6 h to 7 d, the intensity of HSP-25-immunoreactivity was found to be disturbed in the coronal odontoblast-layer in an energy-dependent manner. At 30 d, tertiary dentin with/without bone-like tissue was formed abundantly in the dental pulp. Statistical analysis revealed that the area occupied by the new hard tissues was significantly wider in 1.5 W-lased specimens than in 0.5 W-lased specimens. An intense HSP-25 immunoreactivity was seen in the odontoblasts underlying the tertiary dentin, whereas immunoreactivity was weak around the bone-like tissue. It was concluded that the GaAlAs laser may induce the formation of tertiary dentin by influencing the secretory activity of odontoblasts. However, higher energies may cause irreversible changes to the pulp, often leading to the formation of an intrapulpal bone-like tissue.

Proteins and dipicolinic acid released during heat shock activation of Bacillus subtilis spores probed by optical spectroscopy

UV fluorescence and absorption spectroscopy from Bacillus subtilis spores detected proteins and dipicolinic acid (DPA) released into the supernatant after heat treatments ranging from 20 degrees to 90 degrees C. The protein and DPA concentration in the supernatant was greater with higher heat treatment temperatures, undergoing a substantial increase for T > or = 60 degrees C, and supporting the theory that spores undergo a phase transition from a glassylike to a rubberylike state at 56 degrees C. Gel electrophoresis detected several small proteins with molecular weights between 6 and 11 kDa. These proteins may be small acid-soluble spore proteins that are present in spores but break down during germination. A 30 kDa protein extracted above 60 degrees C is related to the rubber-glass phase transition.

Targeting heat shock proteins for immunotherapy in multiple myeloma: generation of myeloma-specific CTLs using dendritic cells pulsed with tumor-derived gp96

PURPOSE

To develop effective immunotherapies for patients with multiple myeloma, it is important to use novel tumor antigens. Recent studies in solid tumors show that tumor-derived heat shock proteins (Hsp) can be used as immunogen; however, no such study has yet been reported in multiple myeloma.

EXPERIMENTAL DESIGN

We examined whether myeloma-derived Hsp gp96 can be used as a myeloma antigen. Specific CTL lines were obtained after repeatedly stimulating T cells with autologous, HLA-A*0201+ dendritic cells pulsed with gp96 derived from HLA-A*0201+ human myeloma cell line (HMCL) U266 or primary myeloma cells.

RESULTS

These T cells lysed not only gp96-pulsed dendritic cells, U266, and other HLA-A*0201+ HMCLs IM-9 and XG1 but also effectively killed HLA-A*0201+ primary myeloma cells from patients. No killing was observed against unpulsed dendritic cells, dendritic cells pulsed with control gp96, HLA-A*0201- HMCLs, and primary myeloma cells, or HLA-A*0201+ nonmyeloma cells. Cytotoxicity was mainly MHC class I/HLA-A*0201 restricted, suggesting that the CTLs recognized gp96-chaperoned peptides on HLA-A*0201 that were derived from shared myeloma antigens and that myeloma cells naturally present these peptides in the context of their surface MHC molecules. Upon antigen stimulation, these T cells secreted IFN-gamma and tumor necrosis factor-alpha, indicating that they belong to type 1 T-cell subsets.

CONCLUSION

These results show that these T cells are potent CTLs that are able to effectively lyse myeloma cells but not normal blood cells and also suggest that Hsps from allogeneic tumor cells may be used as vaccines to immunize patients.

Rab1 defines a novel pathway connecting the pre-Golgi intermediate compartment with the cell periphery

The function of the pre-Golgi intermediate compartment (IC) and its relationship with the endoplasmic reticulum (ER) and Golgi remain only partially understood. Here, we report striking segregation of IC domains in polarized PC12 cells that develop neurite-like processes. Differentiation involves expansion of the IC and movement of Rab1-containing tubules to the growth cones of the neurites, whereas p58- and COPI-positive IC elements, like rough ER and Golgi, remain in the cell body. Exclusion of Rab1 effectors p115 and GM130 from the neurites further indicated that the centrifugal, Rab1-mediated pathway has functions that are not directly related to ER-to-Golgi trafficking. Disassembly of COPI coats did not affect this pathway but resulted in missorting of p58 to the neurites. Live cell imaging showed that green fluorescent protein (GFP)-Rab1A-containing IC elements move bidirectionally both within the neurites and cell bodies, interconnecting different ER exit sites and the cis-Golgi region. Moreover, in nonpolarized cells GFP-Rab1A-positive tubules moved centrifugally towards the cell cortex. Hydroxymethylglutaryl-CoA reductase, the key enzyme of cholesterol biosynthesis, colocalized with slowly sedimenting, Rab1-enriched membranes when the IC subdomains were separated by velocity sedimentation. These results reveal a novel pathway directly connecting the IC with the cell periphery and suggest that this Rab1-mediated pathway is linked to the dynamics of smooth ER.

Listeria monocytogenes ferritin protects against multiple stresses and is required for virulence

In this study, the role of Listeria monocytogenes ferritin was investigated. The fri gene encoding the ferritin was deleted and the phenotype of the mutant was analyzed demonstrating that ferritin is necessary for optimal growth in minimal medium in both presence and absence of iron, as well as after cold- and heat-shock. We also showed that ferritin provides protection against reactive oxygen species and is essential for full virulence of L. monocytogenes. A comparative proteomic analysis revealed an effect of the fri deletion on the levels of listeriolysin O and several stress proteins. Together, our study demonstrates that fri has multiple roles that contribute to Listeria virulence.

Expression of stress inducible protein 1 (Stip1) in the mouse testis

Phthalate esters are considered endocrine disruptors that interfere with the endocrine balance and development of the mammalian testis. Mono-2-ethylhexyl phthalate (MEHP), the active metabolite of the ubiquitously used plasticizer di-2-ethylhexyl phthalate (DEHP), acts upon Sertoli cells as initial target. By subtractive cDNA libraries we identified genes deregulated as response to MEHP in primary cultures of mouse Sertoli cells. The expression of mouse stress inducible protein 1 (Stip1) was detected as upregulated as a result of MEHP exposure. Stip1 is a cochaperone protein that is homologous to the human heat shock cognate protein 70 (hsc70)/heat shock protein 90 (hsp90)-organizing protein (Hop). To assess the presence and localization of Stip1 in mouse testis and its potential role in stress defense, we studied the expression pattern of the Stip1 protein by immunohistochemistry and of the mRNA by in situ hybridization. Both the protein and the mRNA of Stip1 were mainly found in the cytoplasm of all types of spermatogonia and spermatocytes up till zygotene, the expression decreased during late pachytene and was very weak in diplotene spermatocytes and round spermatids. Interestingly, this expression pattern resembled the pattern of stress sensitivity of spermatogenic cells in that the most sensitive cell types show the weakest expression of Stip1. This suggests an important role for Stip1 in the ability of germ cells to survive in stress conditions including high temperatures.

The value of immunohistochemical research on PCNA, p53 and heat shock proteins in prostate cancer management: a review

This review addresses the significance of the expression of proliferating cell nuclear antigen (PCNA), p53 and some heat shock proteins (Hsps) in prostate carcinoma (PC). In fact, PCNA and p53 are two widely discussed tools in PC diagnosis, mainly because of the controversy regarding the significance of their expression during prostate cancer development and progression. At the same time, only few studies have shown the potential role of Hsps in carcinogenesis and their overexpression in pre-neoplastic and neoplastic lesions of the prostate. We briefly describe the physiological roles of Hsps in normal cells, and the significance of their immunohistochemical detection in PC as well as in pre-cancerous lesions of the prostate. We will also discuss the possible functional interactions of these molecules in both dysplastic and neoplastic cells.