Immunohistochemistry of Human Hsp60 in Health and Disease: From Autoimmunity to Cancer.

Hsp60 (also called Cpn60) is a chaperonin with essential functions for cell physiology and survival. Additionally, its involvement in the pathogenesis of a variety of diseases (e.g., some autoimmune disorders and cancer) is becoming evident with new research. For example, the distribution and levels of Hsp60 in cells and tissues have been found altered in many pathologic conditions, and the significance of these alterations is being investigated in a number of laboratories. The aim of this ongoing research is to determine the meaning of these Hsp60 alterations with regard to pathogenetic mechanisms, diagnosis, classification of lesions, and assessing prognosis and response to treatment.Hsp60 occurs in the mitochondria, i.e., its typical residence according to classic knowledge, and also in other locales, such as the cytosol, the cell membrane, the intercellular space, and biological fluids (e.g., blood and cerebrospinal fluid). Detection and quantitative determinations in all these locations are becoming essential components of laboratory pathology in clinics and research. Consequently, immunohistochemistry targeting Hsp60 is also becoming essential for pathologists and researchers interested in disorders involving this chaperonin.In this chapter, we summarize some recent discoveries on the participation of Hsp60 in the pathogenesis of human diseases, and describe in detail how to perform immunohistochemical reactions for detecting the chaperonin, determining its location, and measuring its quantitative levels.

Functional characterization of a novel 3D model of the epithelial-mesenchymal trophic unit.

BACKGROUND/AIM: Epithelial-mesenchymal communication plays a key role in tissue homeostasis and abnormal signaling contributes to chronic airways disease such as COPD. Most in vitro models are limited in complexity and poorly represent this epithelial-mesenchymal trophic unit. We postulated that cellular outgrowth from bronchial tissue would enable development of a mucosal structure that recapitulates better in vivo tissue architecture. MATERIALS AND METHODS: Bronchial tissue was embedded in Matrigel and outgrowth cultures monitored using time-lapse microscopy, electrical resistance, light and electron microscopy. Cultures were challenged repetitively with cigarette smoke extract (CSE). RESULTS: The outgrowths formed as a multicellular sheet with motile cilia becoming evident as the Matrigel was remodeled to provide an air interface; cultures were viable for more than one year. Immunofluorescence and electron microscopy (EM) identified an upper layer of mucociliary epithelium and a lower layer of highly organized extracellular matrix (ECM) interspersed with fibroblastic cells separated by a basement membrane. EM analysis of the mucosal construct after repetitive exposure to CSE revealed epithelial damage, loss of cilia, and ECM remodeling, as occurs in vivo. CONCLUSIONS: We have developed a robust bronchial mucosal model. The structural changes observed following CSE exposure suggest the model should have utility for drug discovery and preclinical testing, especially those targeting airway remodeling.

The dissociation of the Hsp60/pro-Caspase-3 complex by bis(pyridyl)oxadiazole copper complex (CubipyOXA) leads to cell death in NCI-H292 cancer cells.

Cell survival and proliferation are central to carcinogenesis, involving various mechanisms among which those that impede apoptosis are important. In this, the role of the molecular chaperone Hsp60 is unclear since it has been reported that it can be both, pro- or anti-apoptotic. A solution to this riddle is crucial to the development of anti-cancer therapies targeting Hsp60. We addressed this question using a tumor cell line, NCI-H292, and [Cu(3,5-bis(2'-pyridyl)-1,2,4-oxadiazole)2(H2O)2](ClO4)2, CubipyOXA, a copper-containing compound with cytotoxic properties. We treated cells with various doses of the compound and measured cell viability; apoptosis indicators; and levels of Hsp60, pro-Caspase-3 (pC3), Caspase-3 (C3), and complex Hsp60/pC3, with complementary methods. The quantitative dose-response curves of the levels of Hsp60, activated C3, inactivated pC3, Hsp60/pC3 complex and indicators of cell apoptosis, and cell death, all coincided to show that CubipyOXA has pro-apoptotic activity and promotes cell death. The curves also indicate that the pro-apoptotic effects of CubipyOXA could likely be due to a lowering of Hsp60 levels and to its blocking the formation of the Hsp60/pC3 complex and/or its dissociating the complex when already formed, thus, interfering with the anti-apoptotic action of Hsp60. These findings shed some light on how a tumor cell may avert apoptosis using Hsp60 and point to the anti-cancer potential of drugs, such as CubipyOXA, which interfere with Hsp60/pC3 complex formation, and thus allow the apoptotic cascade to proceed. In view of these findings it becomes clear that the novel compound CubipyOXA should be considered a potential, high-efficiency antitumor agent deserving further testing.

Doxorubicin anti-tumor mechanisms include Hsp60 post-translational modifications leading to the Hsp60/p53 complex dissociation and instauration of replicative senescence.

The chaperone Hsp60 is pro-carcinogenic in certain tumor types by interfering with apoptosis and with tumor cell death. In these tumors, it is not yet known whether doxorubicin anti-tumor effects include a blockage of the pro-carcinogenic action of Hsp60. We found a doxorubicin dose-dependent viability reduction in a human lung mucoepidermoid cell line that was paralleled by the appearance of cell senescence markers. Concomitantly, intracellular Hsp60 levels decreased while its acetylation levels increased. The data suggest that Hsp60 acetylation interferes with the formation of the Hsp60/p53 complex and/or promote its dissociation, both causing an increase in the levels of free p53, which can then activate the p53-dependent pathway toward cell senescence. On the other hand, acetylated Hsp60 is ubiquitinated and degraded and, thus, the anti-apoptotic effect of the chaperonin is abolished with subsequent tumor cell death. Our findings could help in the elucidation of the molecular mechanisms by which doxorubicin counteracts carcinogenesis and, consequently, it would open new roads for the development of cancer treatment protocols targeting Hsp60.

Effects of Conjugated Linoleic Acid Associated With Endurance Exercise on Muscle Fibres and Peroxisome Proliferator-Activated Receptor γ Coactivator 1 α Isoforms.

Conjugated linoleic acid (CLA) has been reported to improve muscle hypertrophy, steroidogenesis, physical activity, and endurance capacity in mice, although the molecular mechanisms of its actions are not completely understood. The aim of the present study was to identify whether CLA alters the expression of any of the peroxisome proliferator-activated receptor γ coactivator 1α (PGC1α) isoforms, and to evaluate the possible existence of fibre-type-specific hypertrophy in the gastrocnemius and plantaris muscles. Mice were randomly assigned to one of four groups: placebo sedentary, CLA sedentary, placebo trained, or CLA trained. The CLA groups were gavaged with 35 µl per day of Tonalin® FFA 80 food supplement containing CLA throughout the 6-week experimental period, whereas the placebo groups were gavaged with 35 µl sunflower oil each day. Each administered dose of CLA corresponded to approximately 0.7 g/kg or 0.5%, of the dietary daily intake. Trained groups ran 5 days per week on a Rota-Rod for 6 weeks at increasing speeds and durations. Mice were sacrificed by cervical dislocation and hind limb posterior muscle groups were dissected and used for histological and molecular analyses. Endurance training stimulated mitochondrial biogenesis by PGC1α isoforms (tot, α1, α2, and α3) but CLA supplementation did not stimulate PGC1α isoforms or mitochondrial biogenesis in trained or sedentary mice. In the plantaris muscle, CLA supplementation induced a fibre-type-specific hypertrophy of type IIx muscle fibres, which was associated with increased capillary density and was different from the fibre-type-specific hypertrophy induced by endurance exercise (of types I and IIb muscle fibres). J. Cell. Physiol. 232: 1086-1094, 2017. © 2016 Wiley Periodicals, Inc.

Nutrition, oxidative stress and intestinal dysbiosis: Influence of diet on gut microbiota in inflammatory bowel diseases.

BACKGROUND: Microbiota refers to the population of microorganisms (bacteria, viruses and fungi) that inhabit the entire gastrointestinal tract, more particularly the colon whose role is to maintain the integrity of the intestinal mucosa and control the proliferation of pathogenic bacteria. Alteration in the composition of the gut microbiota is called dysbiosis. Dysbiosis redisposes to inflammatory bowel diseases such as ulcerative colitis, Crohn disease and indeterminate colitis. METHODS: The purpose of this literature review is to elucidate the influence of diet on the composition of the gastrointestinal microbiota in the healthy gut and the role of diet in the development of dysbiosis. CONCLUSION: The "Western diet", in particular a low - fiber high fat/high carbohydrate diet is one factor that can lead to severe dysbiosis. In contrast, "mediterranean" and vegetarian diets that includes abundant fruits, vegetables, olive oil and oily fish are known for their anti-inflammatory effects and could prevent dysbiosis and subsequent inflammatory bowel disease.

Quantitative patterns of Hsps in tubular adenoma compared with normal and tumor tissues reveal the value of Hsp10 and Hsp60 in early diagnosis of large bowel cancer.

Large bowel carcinogenesis involves accumulation of genetic alterations leading to transformation of normal mucosa into dysplasia and, lastly, adenocarcinoma. It is pertinent to elucidate the molecular changes occurring in the pre-neoplastic lesions to facilitate early diagnosis and treatment. Heat shock proteins (Hsps), many of which are molecular chaperones, are implicated in carcinogenesis, and their variations with tumor progression encourage their study as biomarkers. There are many reports on Hsps and cancer but none to our knowledge on their systematic quantification in pre-neoplastic lesions of the large bowel. We performed immunohistochemical determinations of Hsp10, Hsp60, Hsp70, and Hsp90 in biopsies of large bowel tubular adenomas with moderate grade of dysplasia and compared to normal mucosa and adenocarcinoma with a moderate grade of differentiation (G2). A significant elevation of Hsp10 and Hsp60 only, i.e., in the absence of elevation of Hsp70 or Hsp90, in both epithelium and lamina propria was found in tubular adenoma by comparison with normal mucosa. In contrast, adenocarcinoma was characterized by the highest levels of Hsp10 and Hsp60 in epithelium and lamina propria, accompanied by the highest levels of Hsp70 only in epithelium and of Hsp90 only in lamina propria, by comparison with normal and tubular adenoma counterparts. Hsp10 and Hsp60 are promising biomarkers for early diagnosis of tubular adenoma and for its differentiation from more advanced malignant lesions. Hsp10 and Hsp60 may be implicated in carcinogenesis from its very early steps and, thus, are potentially convenient targets for therapy.

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

OBJECTIVES: Alcoholism is one of the most devastating diseases with high incidence, but knowledge of its pathology and treatment is still plagued with gaps mostly because of the inherent limitations of research with patients. We developed an animal model for studying liver histopathology, Hsp (heat-shock protein)-chaperones involvement, and response to treatment. METHODS: The system was standardized using mice to which ethanol was orally administered alone or in combination with Lactobacillus fermentum following a precise schedule over time and applying, at predetermined intervals, a battery of techniques (histology, immunohistochemistry, western blotting, real-time PCR, immunoprecipitation, 3-nitrotyrosine labeling) to assess liver pathology (e.g., steatosis, fibrosis), and Hsp60 and iNOS (inducible form of nitric oxide synthase) gene expression and protein levels, and post-translational modifications. RESULTS: Typical ethanol-induced liver pathology occurred and the effect of the probiotic could be reliably monitored. Steatosis score, iNOS levels, and nitrated proteins (e.g., Hsp60) decreased after probiotic intake. CONCLUSIONS: We describe a mouse model useful for studying liver disease induced by chronic ethanol intake and for testing pertinent therapeutic agents, e.g., probiotics. We tested L. fermentum, which reduced considerably ethanol-induced tissue damage and deleterious post-translational modifications of the chaperone Hsp60. The model is available to test other agents and probiotics with therapeutic potential in alcoholic liver disease.

Skeletal muscle Heat shock protein 60 increases after endurance training and induces peroxisome proliferator-activated receptor gamma coactivator 1 α1 expression.

Heat shock protein 60 (Hsp60) is a chaperone localizing in skeletal muscle mitochondria, whose role is poorly understood. In the present study, the levels of Hsp60 in fibres of the entire posterior group of hindlimb muscles (gastrocnemius, soleus, and plantaris) were evaluated in mice after completing a 6-week endurance training program. The correlation between Hsp60 levels and the expression of four isoforms of peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PGC1α) were investigated only in soleus. Short-term overexpression of hsp60, achieved by in vitro plasmid transfection, was then performed to determine whether this chaperone could have a role in the activation of the expression levels of PGC1α isoforms. The levels of Hsp60 protein were fibre-type specific in the posterior muscles and endurance training increased its content in type I muscle fibers. Concomitantly with the increased levels of Hsp60 released in the blood stream of trained mice, mitochondrial copy number and the expression of three isoforms of PGC1α increased. Overexpressing hsp60 in cultured myoblasts induced only the expression of PGC1 1α, suggesting a correlation between Hsp60 overexpression and PGC1 1 α activation.

Comparative analysis of the structure of temporomandibular joint in human and rabbit.

In order to increase knowledge on the morphology and structure of the articular disc of the TMJ for a better understanding of the functional role of the same, it proceeded with an investigation on histological samples in the block of 'TMJ and periarticular tissues of adult rabbits and human fetuses at different stage of development.

Heat shock protein 60 levels in tissue and circulating exosomes in human large bowel cancer before and after ablative surgery.

BACKGROUND: Heat shock protein 60 (Hsp60) is a chaperonin involved in tumorigenesis, but its participation in tumor development and progression is not well understood and its value as a tumor biomarker has not been fully elucidated. In the current study, the authors presented evidence supporting the theory that Hsp60 has potential as a biomarker as well as a therapeutic target in patients with large bowel cancer. METHODS: The authors studied a population of 97 subjects, including patients and controls. Immunomorphology, Western blot analysis, and quantitative real-time polymerase chain reaction were performed on tissue specimens. Exosomes were isolated from blood and characterized by electron microscopy, biochemical tests, and Western blot analysis. RESULTS: Hsp60 was found to be increased in cancerous tissue, in which it was localized in the tumor cell plasma membrane, and in the interstitium associated with cells of the immune system, in which it was associated with exosomes liberated by tumor cells and, as such, circulated in the blood. An interesting finding was that these parameters returned to normal shortly after tumor removal. CONCLUSIONS: The data from the current study suggested that Hsp60 is a good candidate for theranostics applied to patients with large bowel carcinoma and encourage similar research among patients with other tumors in which Hsp60 has been implicated.

Cigarette smoke causes caspase-independent apoptosis of bronchial epithelial cells from asthmatic donors.

BACKGROUND: Epidemiologic studies have demonstrated important links between air pollution and asthma. Amongst these pollutants, environmental cigarette smoke is a risk factor both for asthma pathogenesis and exacerbation. As the barrier to the inhaled environment, the bronchial epithelium is a key structure that is exposed to cigarette smoke. OBJECTIVES: Since primary bronchial epithelial cells (PBECs) from asthmatic donors are more susceptible to oxidant-induced apoptosis, we hypothesized that they would be susceptible to cigarette smoke-induced cell death. METHODS: PBECs from normal and asthmatic donors were exposed to cigarette smoke extract (CSE); cell survival and apoptosis were assessed by fluorescence-activated cell sorting, and protective effects of antioxidants evaluated. The mechanism of cell death was evaluated using caspase inhibitors and immunofluorescent staining for apoptosis-inducing factor (AIF). RESULTS: Exposure of PBEC cultures to CSE resulted in a dose-dependent increase in cell death. At 20% CSE, PBECs from asthmatic donors exhibited significantly more apoptosis than cells from non-asthmatic controls. Reduced glutathione (GSH), but not ascorbic acid (AA), protected against CSE-induced apoptosis. To investigate mechanisms of CSE-induced apoptosis, caspase-3 or -9 inhibitors were tested, but these failed to prevent apoptosis; in contrast, CSE promoted nuclear translocation of AIF from the mitochondria. GSH reduced the number of nuclear-AIF positive cells whereas AA was ineffective. CONCLUSION: Our results show that PBECs from asthmatic donors are more susceptible to CSE-induced apoptosis. This response involves AIF, which has been implicated in DNA damage and ROS-mediated cell-death. Epithelial susceptibility to CSE may contribute to the impact of environmental tobacco smoke in asthma.

Hsp60 response in experimental and human temporal lobe epilepsy.

The mitochondrial chaperonin Hsp60 is a ubiquitous molecule with multiple roles, constitutively expressed and inducible by oxidative stress. In the brain, Hsp60 is widely distributed and has been implicated in neurological disorders, including epilepsy. A role for mitochondria and oxidative stress has been proposed in epileptogenesis of temporal lobe epilepsy (TLE). Here, we investigated the involvement of Hsp60 in TLE using animal and human samples. Hsp60 immunoreactivity in the hippocampus, measured by Western blotting and immunohistochemistry, was increased in a rat model of TLE. Hsp60 was also increased in the hippocampal dentate gyrus neurons somata and neuropil and hippocampus proper (CA3, CA1) of the epileptic rats. We also determined the circulating levels of Hsp60 in epileptic animals and TLE patients using ELISA. The epileptic rats showed circulating levels of Hsp60 higher than controls. Likewise, plasma post-seizure Hsp60 levels in patients were higher than before the seizure and those of controls. These results demonstrate that Hsp60 is increased in both animals and patients with TLE in affected tissues, and in plasma in response to epileptic seizures, and point to it as biomarker of hippocampal stress potentially useful for diagnosis and patient management.

Silk fibroin scaffolds enhance cell commitment of adult rat cardiac progenitor cells.

The use of three-dimensional (3D) cultures may induce cardiac progenitor cells to synthesize their own extracellular matrix (ECM) and sarcomeric proteins to initiate cardiac differentiation. 3D cultures grown on synthetic scaffolds may favour the implantation and survival of stem cells for cell therapy when pharmacological therapies are not efficient in curing cardiovascular diseases and when organ transplantation remains the only treatment able to rescue the patient's life. Silk fibroin-based scaffolds may be used to increase cell affinity to biomaterials and may be chemically modified to improve cell adhesion. In the present study, porous, partially orientated and electrospun nanometric nets were used. Cardiac progenitor cells isolated from adult rats were seeded by capillarity in the 3D structures and cultured inside inserts for 21 days. Under this condition, the cells expressed a high level of sarcomeric and cardiac proteins and synthesized a great quantity of ECM. In particular, partially orientated scaffolds induced the synthesis of titin, which is a fundamental protein in sarcomere assembly.

Data mining-based statistical analysis of biological data uncovers hidden significance: clustering Hashimoto's thyroiditis patients based on the response of their PBMC with IL-2 and IFN-γ secretion to stimulation with Hsp60.

The pathogenesis of Hashimoto's thyroiditis includes autoimmunity involving thyroid antigens, autoantibodies, and possibly cytokines. It is unclear what role plays Hsp60, but our recent data indicate that it may contribute to pathogenesis as an autoantigen. Its role in the induction of cytokine production, pro- or anti-inflammatory, was not elucidated, except that we found that peripheral blood mononucleated cells (PBMC) from patients or from healthy controls did not respond with cytokine production upon stimulation by Hsp60 in vitro with patterns that would differentiate patients from controls with statistical significance. This "negative" outcome appeared when the data were pooled and analyzed with conventional statistical methods. We re-analyzed our data with non-conventional statistical methods based on data mining using the classification and regression tree learning algorithm and clustering methodology. The results indicate that by focusing on IFN-γ and IL-2 levels before and after Hsp60 stimulation of PBMC in each patient, it is possible to differentiate patients from controls. A major general conclusion is that when trying to identify disease markers such as levels of cytokines and Hsp60, reference to standards obtained from pooled data from many patients may be misleading. The chosen biomarker, e.g., production of IFN-γ and IL-2 by PBMC upon stimulation with Hsp60, must be assessed before and after stimulation and the results compared within each patient and analyzed with conventional and data mining statistical methods.

Comparative analysis of Hsp10 and Hsp90 expression in healthy mucosa and adenocarcinoma of the large bowel.

BACKGROUND: Heat shock proteins (Hsps) assist other proteins in their folding and drive the degradation of defective proteins. During evolution, these proteins have also acquired other roles. Hsp10 is involved in immunomodulation and tumor progression. Hsp90 stabilizes a range of "client" proteins involved in cell signaling. The present study evaluated the expression levels of Hsp10 and Hsp90 in normal mucosa and adenocarcinoma samples of human large bowel. MATERIALS AND METHODS: Samples of normal mucosa and adenocarcinoma were collected and Reverse transcriptase-polymerase chain reaction RT-PCR, western blotting (WB) analyses, as well as immunohistochemistry were performed to evaluate the expression levels of Hsp10 and Hsp90. RESULTS: RT-PCR showed a higher gene expression of Hsp10 and Hsp90 in adenocarcinoma samples compared to healthy mucosa. WB results confirmed these findings. Immunohistochemistry revealed higher levels of Hsp10 in adenocarcinoma in both the epithelium and the lamina propria, while Hsp90 expression was higher in the adenocarcinoma samples only in the lamina propria. CONCLUSION: Hsp10 and Hsp90 may be involved in large bowel carcinogenesis.

Human Hsp60 with its mitochondrial import signal occurs in solution as heptamers and tetradecamers remarkably stable over a wide range of concentrations.

It has been established that Hsp60 can accumulate in the cytosol in various pathological conditions, including cancer and chronic inflammatory diseases. Part or all of the cytosolic Hsp60 could be naïve, namely, bear the mitochondrial import signal (MIS), but neither the structure nor the in solution oligomeric organization of this cytosolic molecule has still been elucidated. Here we present a detailed study of the structure and self-organization of naïve cytosolic Hsp60 in solution. Results were obtained by different biophysical methods (light and X ray scattering, single molecule spectroscopy and hydrodynamics) that all together allowed us to assay a wide range of concentrations of Hsp60. We found that Naïve Hsp60 in aqueous solution is assembled in very stable heptamers and tetradecamers at all concentrations assayed, without any trace of monomer presence.

Elevated blood Hsp60, its structural similarities and cross-reactivity with thyroid molecules, and its presence on the plasma membrane of oncocytes point to the chaperonin as an immunopathogenic factor in Hashimoto's thyroiditis.

The role Hsp60 might play in various inflammatory and autoimmune diseases is under investigation, but little information exists pertaining to Hashimoto's thyroiditis (HT). With the aim to fill this gap, in the present work, we directed our attention to Hsp60 participation in HT pathogenesis. We found Hsp60 levels increased in the blood of HT patients compared to controls. The chaperonin was immunolocalized in thyroid tissue specimens from patients with HT, both in thyrocytes and oncocytes (Hurthle cells) with higher levels compared to controls (goiter). In oncocytes, we found Hsp60 not only in the cytoplasm but also on the plasma membrane, as shown by double immunofluorescence performed on fine needle aspiration cytology. By bioinformatics, we found regions in the Hsp60 molecule with remarkable structural similarity with the thyroglobulin (TG) and thyroid peroxidase (TPO) molecules, which supports the notion that autoantibodies against TG and TPO are likely to recognize Hsp60 on the plasma membrane of oncocytes. This was also supported by data obtained by ELISA, showing that anti-TG and anti-TPO antibodies cross-react with human recombinant Hsp60. Antibody-antigen (Hsp60) reaction on the cell surface could very well mediate thyroid cell damage and destruction, perpetuating inflammation. Experiments with recombinant Hsp60 did not show stimulation of cytokine production by peripheral blood mononuclear cells from HT patients. All together, these results led us to hypothesize that Hsp60 may be an active player in HT pathogenesis via an antibody-mediated immune mechanism.

Endurance exercise and conjugated linoleic acid (CLA) supplementation up-regulate CYP17A1 and stimulate testosterone biosynthesis.

A new role for fat supplements, in particular conjugated linoleic acid (CLA), has been delineated in steroidogenesis, although the underlying molecular mechanisms have not yet been elucidated. The aims of the present study were to identify the pathway stimulated by CLA supplementation using a cell culture model and to determine whether this same pathway is also stimulated in vivo by CLA supplementation associated with exercise. In vitro, Leydig tumour rat cells (R2C) supplemented with different concentrations of CLA exhibited increasing testosterone biosynthesis accompanied by increasing levels of CYP17A1 mRNA and protein. In vivo, trained mice showed an increase in free plasma testosterone and an up-regulation of CYP17A1 mRNA and protein. The effect of training on CYP17A1 expression and testosterone biosynthesis was significantly higher in the trained mice supplemented with CLA compared to the placebo. The results of the present study demonstrated that CLA stimulates testosterone biosynthesis via CYP17A1, and endurance training led to the synthesis of testosterone in vivo by inducing the overexpression of CYP17A1 mRNA and protein in the Leydig cells of the testis. This effect was enhanced by CLA supplementation. Therefore, CLA-associated physical activity may be used for its steroidogenic property in different fields, such as alimentary industry, human reproductive medicine, sport science, and anti-muscle wasting.