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Laryngeal squamous cell carcinoma (LSCC) constitutes a noteworthy subset of head and neck cancers, contributing to about 4.5% of all malignancies. Its clinical behavior and characteristics exhibit variations contingent upon the specific anatomical site affected, with the glottis, supraglottis, and subglottis emerging as the most prevalent locations. Notably, squamous cell carcinoma represents a predominant histological type, accounting for 85% to 95% of all laryngeal cancers. The gender disparity is evident, with a higher incidence among males, exhibiting a ratio of 3.9:1. Moreover, disparities among racial groups are observed, as African American patients tend to manifest the condition at a younger age, coupled with lower overall survival rates compared to their Caucasian, Hispanic, and Asian counterparts. The primary etiological factors implicated in the onset of laryngeal cancer are tobacco and alcohol consumption, with a direct correlation to the intensity and duration of usage. Importantly, the risk diminishes gradually following cessation, necessitating a substantial period of at least 15 years for a return to baseline rates. Given the diverse nature of laryngeal SCC, treatment modalities are tailored based on the specific site and stage of the disease. Therapeutic interventions, such as radiotherapy, transoral laser microsurgery, open horizontal partial laryngectomy, or total laryngectomy, are employed with the overarching goal of preserving organ function. This study delves into the intricate realm of laryngeal SCC, specifically exploring the involvement of heat shock proteins (HSPs) in disease progression. This research meticulously examines the expression levels of Hsp10, Hsp27, Hsp60, and Hsp90 in dysplastic and benign tissue samples extracted from the right vocal cord, utilizing immunohistochemistry analysis. The focal point of the investigation revolves around unraveling the intricate role of these molecular chaperones in tissue differentiation mechanisms and cellular homeostasis, particularly within the inflammatory milieu characteristic of the tumor phenotype. The findings from this study serve as a robust histopathological foundation, paving the way for more in-depth analyses of the underlying mechanisms governing the contribution of the four chaperones to the development of squamous cell carcinoma in the larynx. Additionally, the data gleaned from this research hint at the potential of these four chaperones as valuable biomarkers, not only for diagnostic purposes but also for prognostication and ongoing patient monitoring. As our understanding of the molecular intricacies deepens, the prospect of targeted therapeutic interventions and personalized treatment strategies for laryngeal SCC becomes increasingly promising. [ABSTRACT FROM AUTHOR]

Background: Anti‐heat shock protein (HSP) autoantibodies are detected in autoimmune diseases. We sought to ascertain whether anti‐HSP10 IgG is present in patients with CSU and to elucidate the role of HSP10 in CSU pathogenesis. Method: Using a human proteome microarray, six potential autoantibodies had higher expression in 10 CSU samples compared with 10 normal controls (NCs). Among them, HSP10 IgG autoantibody was quantified by immune dot‐blot assay in sera from 86 CSU patients and 44 NCs. The serum levels of HSP10 and microRNA‐101‐5p were measured in CSU patients and NCs. The effects of HSP10 and miR‐101‐5p on mast cell degranulation in response to IgE, compound 48/80, and platelet‐activating factor (PAF) were investigated. Results: CSU patients had higher IgG positivity to HSP10 (40.7% vs. 11.4%, p =.001), lower serum HSP10 levels (5.8 ± 3.6 vs. 12.2 ± 6.6 pg/mL, p <.001) than in NCs, and their urticaria severity was associated with anti‐HSP10 IgG positivity, while HSP10 levels were related to urticaria control status. MiR‐101‐5p was increased in CSU patients. PAF enhanced IL4 production in PBMCs from CSU patients. IL‐4 upregulated miR‐101‐5p and reduced HSP10 expression in keratinocytes. Transfection of miR‐101‐5p reduced HSP10 expression in keratinocytes. MiR‐101‐5p promoted PAF‐induced mast cell degranulation, while HSP10 specifically prevented it. Conclusion: A new autoantibody, anti‐HSP10 IgG was detected in CSU patients, which showed a significant correlation with UAS7 scores. A decreased serum HSP10 level was associated with upregulation of miR‐101‐5p due to increased IL‐4 and PAF in CSU patients. Modulation of miR‐101‐5p and HSP10 may be a novel therapeutic approach for CSU. [ABSTRACT FROM AUTHOR]

Chlorpromazine (CPZ), a first‐generation antipsychotic, is widely used in treating schizophrenia and other psychiatric disorders. However, CPZ is also associated with an increased likelihood of sudden cardiac death, and the underlying mechanisms remain unclear. In our study, we aimed to determine the CPZ‐induced changes in some members of the heat shock protein family in rat hearts and further explore the possible mechanisms of CPZ‐induced cardiotoxicity. Twenty‐four Sprague Dawley rats were randomly divided into three groups (n = 8 per group): control, low dose (33.216 mg/kg) and high dose (94.211 mg/kg). CPZ administration induced hypothermia in rats. Pathological changes, including ischaemia and hypoxia, were observed in rat hearts. Furthermore, the serum levels of cardiac Troponin T (c‐TN‐T) and brain natriuretic peptide (BNP) were elevated in the CPZ‐exposed groups. Meanwhile, the protein and gene expression of HSP70, HSP60, HSP27 and HSP10 significantly differed between the CPZ‐exposed and control groups. We conclude that acute CPZ exposure could lead to myocardial injury in rats, in which HSPs might play a crucial role. Further investigations are required to elucidate the underlying mechanisms. To explore the cardiotoxicity mechanism of chlorpromazine (CPZ), 24 Sprague Dawley rats were randomly divided into three groups (n = 8 per group): control, low dose (33.216 mg/kg) and high dose (94.211 mg/kg). Observed pathological changes in rat hearts included ischaemia and hypoxia, and the serum levels of c‐TN‐T and BNP were elevated in the CPZ‐exposed groups. The protein and gene expression of HSP70, HSP60, HSP27 and HSP10 significantly differed between the CPZ‐exposed and control groups. [ABSTRACT FROM AUTHOR]

Simple Summary: A. m. jemenetica occurs naturally on the Arabian Peninsula and in tropical Africa, and this honeybee subspecies has acquired several morphological, behavioral and molecular adaptations to extreme summer temperatures in Saudi Arabia. In this study, expression levels of different heat-shock protein (hsp) genes in forager A. m. jemenetica (a thermotolerant honeybee subspecies) and A. m. carnica (a thermosusceptible subspecies) were explored and compared under desert and semi-arid climates within Saudi Arabia. The results revealed higher expression levels of hsp mRNAs in A. m. jemenetica compared to A. m. carnica. The expression levels of small- as well as large-molecular-weight heat-shock proteins were higher under desert climate conditions in the Riyadh region compared to the semi-arid conditions in Baha. It is clear that the expression of heat-shock proteins is a key molecular mechanism of A. m. jemenetica adaptation to extreme summer conditions. A. m. jemenetica is the indigenous honeybee of the Arabian Peninsula. It is highly adapted to extreme temperatures exceeding 40 °C, yet important molecular aspects of its adaptation are not well documented. In this study we quantify relative expression levels of small- and large-molecular-weight heat-shock proteins (hsp10, hsp28, hsp70, hsp83, hsp90 and hsc70 (mRNAs)) in the thermos-tolerant A. m. jemenetica and thermosusceptible A. m. carnica forager honeybee subspecies under desert (Riyadh) and semi-arid (Baha) summer conditions. The results showed significant day-long higher expression levels of hsp mRNAs in A. m. jemenetica compared to A. m. carnica under the same conditions. In Baha, the expression levels were very modest in both subspecies compared those in Riyadh though the expression levels were higher in A. m. jemenetica. The results also revealed a significant interaction between subspecies, which indicated milder stress conditions in Baha. In conclusion, the higher expression levels of hsp10, hsp28, hsp70ab, hsp83 and hsp90 mRNAs in A. m. jemenetica are key elements in the adaptive nature of A. m. jemenetica to local conditions that enhance its survival and fitness in high summer temperatures. [ABSTRACT FROM AUTHOR]

Laryngeal squamous cell carcinoma (LSCC) constitutes a noteworthy subset of head and neck cancers, contributing to about 4.5% of all malignancies. Its clinical behavior and characteristics exhibit variations contingent upon the specific anatomical site affected, with the glottis, supraglottis, and subglottis emerging as the most prevalent locations. Notably, squamous cell carcinoma represents a predominant histological type, accounting for 85% to 95% of all laryngeal cancers. The gender disparity is evident, with a higher incidence among males, exhibiting a ratio of 3.9:1. Moreover, disparities among racial groups are observed, as African American patients tend to manifest the condition at a younger age, coupled with lower overall survival rates compared to their Caucasian, Hispanic, and Asian counterparts. The primary etiological factors implicated in the onset of laryngeal cancer are tobacco and alcohol consumption, with a direct correlation to the intensity and duration of usage. Importantly, the risk diminishes gradually following cessation, necessitating a substantial period of at least 15 years for a return to baseline rates. Given the diverse nature of laryngeal SCC, treatment modalities are tailored based on the specific site and stage of the disease. Therapeutic interventions, such as radiotherapy, transoral laser microsurgery, open horizontal partial laryngectomy, or total laryngectomy, are employed with the overarching goal of preserving organ function. This study delves into the intricate realm of laryngeal SCC, specifically exploring the involvement of heat shock proteins (HSPs) in disease progression. This research meticulously examines the expression levels of Hsp10, Hsp27, Hsp60, and Hsp90 in dysplastic and benign tissue samples extracted from the right vocal cord, utilizing immunohistochemistry analysis. The focal point of the investigation revolves around unraveling the intricate role of these molecular chaperones in tissue differentiation mechanisms and cellular homeostasis, particularly within the inflammatory milieu characteristic of the tumor phenotype. The findings from this study serve as a robust histopathological foundation, paving the way for more in-depth analyses of the underlying mechanisms governing the contribution of the four chaperones to the development of squamous cell carcinoma in the larynx. Additionally, the data gleaned from this research hint at the potential of these four chaperones as valuable biomarkers, not only for diagnostic purposes but also for prognostication and ongoing patient monitoring. As our understanding of the molecular intricacies deepens, the prospect of targeted therapeutic interventions and personalized treatment strategies for laryngeal SCC becomes increasingly promising.

Neurodegenerative diseases (NDs) are associated with accumulated misfolded proteins (MPs). MPs oligomerize and form multiple forms of amyloid fibril polymorphs that dictate fibril propagation and cellular dysfunction. Protein misfolding processes that impair protein homeostasis are implicated in onset and progression of NDs. A wide variety of molecular chaperones safeguard the cell from MP accumulation. A rather overlooked molecular chaperone is HSP10, known as a co-chaperone for HSP60. Due to the ubiquitous presence in human tissues and protein overabundance compared with HSP60, we studied how HSP10 alone influences fibril formation in vitro of Alzheimer's disease-associated Aβ1–42. At sub-stoichiometric concentrations, eukaryotic HSP10s (human and Drosophila) significantly influenced the fibril formation process and the fibril structure of Aβ1–42, more so than the prokaryotic HSP10 GroES. Similar effects were observed for prion disease-associated prion protein HuPrP90–231. Paradoxically, for a chaperone, low concentrations of HSP10 appeared to promote fibril nucleation by shortened lag-phases, which were chaperone and substrate dependent. Higher concentrations of chaperone while still sub-stoichiometric extended the nucleation and/or the elongation phase. We hypothesized that HSP10 by means of its seven mobile loops provides the chaperone with high avidity binding to amyloid fibril ends. The preserved sequence of the edge of the mobile loop GGIM(V)L (29–33 human numbering) normally dock to the HSP60 apical domain. Interestingly, this segment shows sequence similarity to amyloidogenic core segments of Aβ1–42, GGVVI (37–41), and HuPrP90-231 GGYML (126–130) likely allowing efficient competitive binding to fibrillar conformations of these MPs. Our results propose that HSP10 can function as an important molecular chaperone in human proteostasis in NDs. [ABSTRACT FROM AUTHOR]

Neurodegenerative diseases (NDs) are associated with accumulated misfolded proteins (MPs). MPs oligomerize and form multiple forms of amyloid fibril polymorphs that dictate fibril propagation and cellular dysfunction. Protein misfolding processes that impair protein homeostasis are implicated in onset and progression of NDs. A wide variety of molecular chaperones safeguard the cell from MP accumulation. A rather overlooked molecular chaperone is HSP10, known as a co-chaperone for HSP60. Due to the ubiquitous presence in human tissues and protein overabundance compared with HSP60, we studied how HSP10 alone influences fibril formation in vitro of Alzheimer’s disease-associated Aβ1–42. At sub-stoichiometric concentrations, eukaryotic HSP10s (human and Drosophila) significantly influenced the fibril formation process and the fibril structure of Aβ1–42, more so than the prokaryotic HSP10 GroES. Similar effects were observed for prion disease-associated prion protein HuPrP90–231. Paradoxically, for a chaperone, low concentrations of HSP10 appeared to promote fibril nucleation by shortened lag-phases, which were chaperone and substrate dependent. Higher concentrations of chaperone while still sub-stoichiometric extended the nucleation and/or the elongation phase. We hypothesized that HSP10 by means of its seven mobile loops provides the chaperone with high avidity binding to amyloid fibril ends. The preserved sequence of the edge of the mobile loop GGIM(V)L (29–33 human numbering) normally dock to the HSP60 apical domain. Interestingly, this segment shows sequence similarity to amyloidogenic core segments of Aβ1–42, GGVVI (37–41), and HuPrP90-231 GGYML (126–130) likely allowing efficient competitive binding to fibrillar conformations of these MPs. Our results propose that HSP10 can function as an important molecular chaperone in human proteostasis in NDs.

Juan Feng,1,2 Yuting Zhan,1 Yuting Zhang,1 Hongmei Zheng,1 Weiyuan Wang,3 Songqing Fan1 1Department of Pathology, The Second Xiangya Hospital, Central South University, Changsha, Hunan, People’s Republic of China; 2Clinical Laboratory of Hunan Prevention and Treatment Institute for Occupational Diseases, Changsha, Hunan, People’s Republic of China; 3Department of Pathology, Xiangya Hospital, Central South University, Changsha, Hunan, People’s Republic of ChinaCorrespondence: Songqing FanDepartment of Pathology, The Second Xiangya Hospital, Central South University, 139 Renmin Middle Road, Changsha, Hunan 410011, People’s Republic of ChinaEmail songqingfan@csu.edu.cnBackground: Heat shock proteins (HSPs) are a large family of chaperones implicating in occurrence and progression of tumor. In our previous study, we found HSP10 correlates with poor prognosis of oral squamous cell carcinoma and astrocytoma. HSP70 is also an important part of this family and whether the alterations of HSP10 and HSP70 expression and their common expression correlates with carcinogenesis and progression of nasopharyngeal carcinoma (NPC) has not been reported.Method: In this study, we investigate the correlation between the expression of HSP10 and HSP70 and clinicopathological characteristics in NPC by immunohistochemistry (IHC).Results: Results indicated that positive expression of HSP10 and HSP70 was higher in NPC tissues (both P

We studied the expression of small heat shock proteins HSP10 and HSP27 in left ventricular cardiomyocytes in animals with arterial hypertension, insulin-dependent diabetes mellitus, and their combination. The experiment was performed on 38-week-old male Wistar-Kyoto and 38-57-week-old SHR (spontaneously hypertensive) rats. Insulin-dependent diabetes mellitus was modeled by single parenteral injection of streptozotocin (65 mg/kg). Expression of HSP10 and HSP27 in left ventricular cardiomyocytes was evaluated by immunohistochemical assay. It was found that the content of HSP10 in the left ventricular cardiomyocytes decreased in comparison with the control in case of isolated diabetes mellitus and, on the contrary, increased in case of arterial hypertension combined with diabetes mellitus. The intensity of HSP27 expression decreased in case of 38-week arterial hypertension and a combination of arterial hypertension with diabetes mellitus. However, in case of 57-week arterial hypertension we observed an increase in the content of HSP27 in cardiomyocytes. [ABSTRACT FROM AUTHOR]

Humoral factors released during ischemic preconditioning (IPC) protect the myocardium against ischemia/reperfusion (I/R) injury. We have recently identified 10 kDa-heat shock protein (HSP10) and a fraction of small 5–10 kDa peptides (5–10-sP) in the coronary effluent of IPC-treated hearts and demonstrated their cardioprotective potential. We here used our isolated mitochondria model to characterize the impact of exogenous HSP10 and 5–10-sP on mitochondria function from myocardium subjected to I/R injury. Isolated perfused rat hearts were submitted to 30-min global ischemia and 10-min reperfusion. Before ischemia, isolated hearts were infused with saline or 5–10-sP, with or without a mitochondrial ATP-sensitive-K+-channel blocker (5HD 10 μmol·L−1) or PKC inhibitor (chelerythrine 10 μmol·L−1), before I/R. HSP10 (1 µmol·L−1) was infused into isolated hearts before I/R without blockers. At 10-min reperfusion, the mitochondria were isolated and mitochondrial function was assessed. In a subset of experiments, freshly isolated mitochondria were directly incubated with HSP10 or 5–10-sP with or without 5HD or chelerythrine before in vitro hypoxia/reoxygenation. Infusion of 5–10-sP (n = 5) and HSP10 (n = 5) into isolated hearts before I/R improved mitochondrial ADP-stimulated respiration, ATP production and prevented mitochondrial ROS formation compared to the I/R group (n = 5); this effect was abrogated by 5HD and chelerythrine. In freshly isolated mitochondria with in vitro hypoxia/reoxygenation, HSP10 (n = 16) and 5–10-sP (n = 16) incubation prevented reductions of mitochondrial ADP-stimulated respiration (91.5 ± 5.1 nmol O2/min/mg PTN), ATP production (250.1 ± 9.3 μmol ATP/200μg PTN), and prevented mitochondrial ROS production (219.7 ± 9.0 nmol H2O2/200μg PTN) induced by hypoxia/reoxygenation (n = 12, 51.5 ± 5.0 nmol O2/min/mg PTN; 187 ± 21.7 μmol ATP/200 μg PTN; 339.0 ± 14.3 nmol H2O2/200 μg PTN, p < 0.001, respectively). 5HD reduced the ADP-stimulated respiration in the HSP10 group (65.84 ± 3.3 nmol O2/min/mg PTN), ATP production (193.7 ± 12.1 μmol ATP/200μg PTN) and increased ROS in the 5–10-sP group (274.4 ± 21.7 nmol H2O2/200 μg PTN). Mitochondria are a target of the cardioprotection induced by 5–10-sP and HSP10. This protection is dependent of PKC and mKATP activation. HSP10 can act directly on mitochondria and protects against hypoxia/reoxygenation injury by mKATP activation.

BACKGROUND: HSP60 and its partner HSP10 are members of heat shock proteins (HSPs) family, which help mitochondrial protein to fold correctly. Mcl-1, a member of the Bcl-2 family, plays a crucial role in regulation of cell apoptosis. Aberrant expression of HSP10, HSP60 and Mcl-1 is involved in the development of many tumors. OBJECTIVE: To examine the association between expression of HSP10, HSP60 and Mcl-1 and clinicopathological features of non-small cell lung cancer (NSCLC). METHODS: Tissue microarrays including 53 non-cancerous lung tissues (Non-CLT) and 354 surgically resected NSCLC were stained with anti-HSP10, anti-HSP60 and anti-Mcl-1 antibodies respectively by immunohistochemistry. RESULTS: Higher expression of HSP10, HSP60 and Mcl-1 was found in NSCLC compared with Non-CLT. Both individual and combined HSP10 and HSP60 expression in patients with clinical stage III was higher than that in stage I ∼ II. Expression of HSP10 showed a positive correlation with HSP60 and Mcl-1. Overall survival time of NSCLC patients was remarkably shorter with elevated expression of HSP10, HSP60 and Mcl-1 alone and in combination. Moreover overexpression of HSP10 and Mcl-1 was poor independent prognostic factor for lung adenocarcinoma patients. CONCLUSIONS: High expression of HSP10, HSP60 and Mcl-1 might act as novel biomarker of poor prognosis for NSCLC patients. [ABSTRACT FROM AUTHOR]

Parkinson's disease (PD) is associated with the accumulation of alpha‐synuclein (aSyn) in intracellular inclusions known as Lewy bodies and Lewy neurites. Under physiological conditions, aSyn is found at the presynaptic terminal and exists in a dynamic equilibrium between soluble, membrane‐associated and aggregated forms. Emerging evidence suggests that, under pathological conditions, aSyn begins to accumulate and acquire a toxic function at the synapse, impairing their normal function and connectivity. However, the precise molecular mechanisms linking aSyn accumulation and synaptic dysfunction are still elusive. Here, we provide an overview of our current findings and discuss the hypothesis that certain aSyn aggregates may interact with proteins with whom aSyn normally does not interact with, thereby trapping them and preventing them from performing their normal functions in the cell. We posit that such abnormal interactions start to occur during the prodromal stages of PD, eventually resulting in the overt manifestation of clinical features. Therefore, understanding the nature and behaviour of toxic aSyn species and their contribution to aSyn‐mediated toxicity is crucial for the development of therapeutic strategies capable of modifying disease progression in PD and other synucleinopathies. [ABSTRACT FROM AUTHOR]

Background: The use of various biomarkers in sepsis has an important role in helping diagnosis and decision making therapy quickly and accurately. This study aimed to explain the mechanism of procalcitonin, IL-1ß, RAMPs markers such as HSP10 and resolvin D2 as biomarkers of sepsis in the sepsis model of Eschericia coli infection given with meropenem antibiotics. Methods: An experimental study using the E. coli sepsis model in male Rattus norvegicuswas conducted in 2 stages. The first step was to observe a model of sepsis in rats and determine the time of sepsis and the second step was to compare levels of procalcitonin, HSP10, IL-1ß, and resolvin D2 with different dosage of germs and different antibiotic time of administration. Results: The time of sepsis was occurred between 8 and 10 hours. There were differences in E. coli exposure with IL-1ß levels (p = 0.03), procalcitonin (p = 0.084), HSP10 (p = 0.000), and resolvin D2 (p = 0.024). There were differences in levels of procalcitonin and resolvin D2 between groups at 24, 48 and 72 hours and between the treatment of antibiotics at different times and without antibiotic administration. While there were differences the levels of IL-1ß and HSP10 between groups at 24 and 72 hours, but there was no difference at 48 hours antibiotic treatments. Conclusion: Resolvin D2 and HSP10 have a slightly different pattern at 24 and 72 hours compared to procalcitonin and HSP10. Thus, it has the potential to be developed as a new biomarker in sepsis. [ABSTRACT FROM AUTHOR]

Humoral factors released during ischemic preconditioning (IPC) protect the myocardium against ischemia/reperfusion (I/R) injury. We have recently identified 10 kDa-heat shock protein (HSP10) and a fraction of small 5–10 kDa peptides (5–10-sP) in the coronary effluent of IPC-treated hearts and demonstrated their cardioprotective potential. We here used our isolated mitochondria model to characterize the impact of exogenous HSP10 and 5–10-sP on mitochondria function from myocardium subjected to I/R injury. Isolated perfused rat hearts were submitted to 30-min global ischemia and 10-min reperfusion. Before ischemia, isolated hearts were infused with saline or 5–10-sP, with or without a mitochondrial ATP-sensitive-K+-channel blocker (5HD 10 μmol·L−1) or PKC inhibitor (chelerythrine 10 μmol·L−1), before I/R. HSP10 (1 µmol·L−1) was infused into isolated hearts before I/R without blockers. At 10-min reperfusion, the mitochondria were isolated and mitochondrial function was assessed. In a subset of experiments, freshly isolated mitochondria were directly incubated with HSP10 or 5–10-sP with or without 5HD or chelerythrine before in vitro hypoxia/reoxygenation. Infusion of 5–10-sP (n = 5) and HSP10 (n = 5) into isolated hearts before I/R improved mitochondrial ADP-stimulated respiration, ATP production and prevented mitochondrial ROS formation compared to the I/R group (n = 5); this effect was abrogated by 5HD and chelerythrine. In freshly isolated mitochondria with in vitro hypoxia/reoxygenation, HSP10 (n = 16) and 5–10-sP (n = 16) incubation prevented reductions of mitochondrial ADP-stimulated respiration (91.5 ± 5.1 nmol O2/min/mg PTN), ATP production (250.1 ± 9.3 μmol ATP/200μg PTN), and prevented mitochondrial ROS production (219.7 ± 9.0 nmol H2O2/200μg PTN) induced by hypoxia/reoxygenation (n = 12, 51.5 ± 5.0 nmol O2/min/mg PTN; 187 ± 21.7 μmol ATP/200 μg PTN; 339.0 ± 14.3 nmol H2O2/200 μg PTN, p < 0.001, respectively). 5HD reduced the ADP-stimulated respiration in the HSP10 group (65.84 ± 3.3 nmol O2/min/mg PTN), ATP production (193.7 ± 12.1 μmol ATP/200μg PTN) and increased ROS in the 5–10-sP group (274.4 ± 21.7 nmol H2O2/200 μg PTN). Mitochondria are a target of the cardioprotection induced by 5–10-sP and HSP10. This protection is dependent of PKC and mKATP activation. HSP10 can act directly on mitochondria and protects against hypoxia/reoxygenation injury by mKATP activation. [ABSTRACT FROM AUTHOR]

Poxviruses utilize multiple strategies to prevent activation of extrinsic and intrinsic apoptotic pathways for successful replication. Mitochondrial heat shock proteins (mtHsps), especially Hsp60 and its cofactor Hsp10, are engaged in apoptosis regulation; however, until now, the influence of poxviruses on mtHsps has never been studied. We used highly infectious Moscow strain of ectromelia virus (ECTV) to investigate the mitochondrial heat shock response and apoptotic potential in permissive L929 fibroblasts. Our results show that ECTV-infected cells exhibit mostly mitochondrial localization of Hsp60 and Hsp10, and show overexpression of both proteins during later stages of infection. ECTV infection has only moderate effect on the electron transport chain subunit expression. Moreover, increase of mtHsp amounts is accompanied by lack of apoptosis, and confirmed by reduced level of pro-apoptotic Bax protein and elevated levels of anti-apoptotic Bcl-2 and Bcl-xL proteins. Taken together, we show a positive relationship between increased levels of Hsp60 and Hsp10 and decreased apoptotic potential of L929 fibroblasts, and further hypothesize that Hsp60 and/or its cofactor play important roles in maintaining protein homeostasis in mitochondria for promotion of cell survival allowing efficient replication of ECTV. [ABSTRACT FROM AUTHOR]

Current treatments for Mycobacterium tuberculosis infections require long and complicated regimens that can lead to patient non-compliance, increasing incidences of antibiotic-resistant strains, and lack of efficacy against latent stages of disease. Thus, new therapeutics are needed to improve tuberculosis standard of care. One strategy is to target protein homeostasis pathways by inhibiting molecular chaperones such as GroEL/ES (HSP60/10) chaperonin systems. M. tuberculosis has two GroEL homologs: GroEL1 is not essential but is important for cytokine-dependent granuloma formation, while GroEL2 is essential for survival and likely functions as the canonical housekeeping chaperonin for folding proteins. Another strategy is to target the protein tyrosine phosphatase B (PtpB) virulence factor that M. tuberculosis secretes into host cells to help evade immune responses. In the present study, we have identified a series of GroEL/ES inhibitors that inhibit M. tuberculosis growth in liquid culture and biochemical function of PtpB in vitro. With further optimization, such dual-targeting GroEL/ES and PtpB inhibitors could be effective against all stages of tuberculosis – actively replicating bacteria, bacteria evading host cell immune responses, and granuloma formation in latent disease – which would be a significant advance to augment current therapeutics that primarily target actively replicating bacteria. [ABSTRACT FROM AUTHOR]

Graphical abstract Screening known drugs and natural products for inhibiting GroEL/ES & HSP60/10 chaperonin systems. Abstract All living organisms contain a unique class of molecular chaperones called 60 kDa heat shock proteins (HSP60 – also known as GroEL in bacteria). While some organisms contain more than one HSP60 or GroEL isoform, at least one isoform has always proven to be essential. Because of this, we have been investigating targeting HSP60 and GroEL chaperonin systems as an antibiotic strategy. Our initial studies focused on applying this antibiotic strategy for treating African sleeping sickness (caused by Trypanosoma brucei parasites) and drug-resistant bacterial infections (in particular Methicillin-resistant Staphylococcus aureus – MRSA). Intriguingly, during our studies we found that three known antibiotics – suramin, closantel, and rafoxanide – were potent inhibitors of bacterial GroEL and human HSP60 chaperonin systems. These findings prompted us to explore what other approved drugs, natural products, and known bioactive molecules might also inhibit HSP60 and GroEL chaperonin systems. Initial high-throughput screening of 3680 approved drugs, natural products, and known bioactives identified 161 hit inhibitors of the Escherichia coli GroEL chaperonin system (4.3% hit rate). From a purchased subset of 60 hits, 29 compounds (48%) re-confirmed as selective GroEL inhibitors in our assays, all of which were nearly equipotent against human HSP60. These findings illuminate the notion that targeting chaperonin systems might be a more common occurrence than we previously appreciated. Future studies are needed to determine if the in vivo modes of action of these approved drugs, natural products, and known bioactive molecules are related to GroEL and HSP60 inhibition. [ABSTRACT FROM AUTHOR]

Galeruca daurica (Joannis) is a new outbreak pest in the Inner Mongolia grasslands in northern China. Heat shock protein 10 and 60 (Hsp10 and Hsp60) genes of G. daurica, designated as GdHsp10 and GdHsp60, were cloned by rapid amplification of cDNA ends techniques. Sequence analysis showed that GdHsp10 and GdHsp60 encoded polypeptides of 104 and 573 amino acids, respectively. Sequence alignment and phylogenetic analysis clearly revealed that the amino acids of GdHsp10 and GdHsp60 had high homology and were clustered with other Hsp10 and Hsp60 genes in insects which are highly relative with G. daurica based on morphologic taxonomy. The mRNA expression analysis by real-time PCR revealed that GdHsp10 and GdHsp60 were expressed at all development stages and in all tissues examined, but expressed highest in eggs and in adults’ abdomen; both heat and cold stresses could induce mRNA expression of GdHsp10 and GdHsp60 in the 2nd instar larvae; the two Hsp genes were expressed from high to low with the extension of treatment time in G. daurica eggs exposed to freezing point. Overall, our study provides useful information to understand temperature stress responses of Hsp60 and Hsp10 in G. daurica, and provides a basis to further study functions of Hsp60/Hsp10 relative to thermotolerance and cold hardiness mechanism. [ABSTRACT FROM AUTHOR]

Trypanosoma brucei are protozoan parasites that cause African sleeping sickness in humans (also known as Human African Trypanosomiasis—HAT). Without treatment, T. brucei infections are fatal. There is an urgent need for new therapeutic strategies as current drugs are toxic, have complex treatment regimens, and are becoming less effective owing to rising antibiotic resistance in parasites. We hypothesize that targeting the HSP60/10 chaperonin systems in T. brucei is a viable anti-trypanosomal strategy as parasites rely on these stress response elements for their development and survival. We recently discovered several hundred inhibitors of the prototypical HSP60/10 chaperonin system from Escherichia coli , termed GroEL/ES. One of the most potent GroEL/ES inhibitors we discovered was compound 1 . While examining the PubChem database, we found that a related analog, 2e - p , exhibited cytotoxicity to Leishmania major promastigotes, which are trypanosomatids highly related to Trypanosoma brucei . Through initial counter-screening, we found that compounds 1 and 2e - p were also cytotoxic to Trypanosoma brucei parasites (EC 50 = 7.9 and 3.1 μM, respectively). These encouraging initial results prompted us to develop a library of inhibitor analogs and examine their anti-parasitic potential in vitro. Of the 49 new chaperonin inhibitors developed, 39% exhibit greater cytotoxicity to T. brucei parasites than parent compound 1 . While many analogs exhibit moderate cytotoxicity to human liver and kidney cells, we identified molecular substructures to pursue for further medicinal chemistry optimization to increase the therapeutic windows of this novel class of chaperonin-targeting anti-parasitic candidates. An intriguing finding from this study is that suramin, the first-line drug for treating early stage T. brucei infections, is also a potent inhibitor of GroEL/ES and HSP60/10 chaperonin systems. [ABSTRACT FROM AUTHOR]

We recently reported results from a high-throughput screening effort that identified 235 inhibitors of the Escherichia coli GroEL/ES chaperonin system [ Bioorg. Med. Chem. Lett. 2014 , 24 , 786]. As the GroEL/ES chaperonin system is essential for growth under all conditions, we reasoned that targeting GroEL/ES with small molecule inhibitors could be a viable antibacterial strategy. Extending from our initial screen, we report here the antibacterial activities of 22 GroEL/ES inhibitors against a panel of Gram-positive and Gram-negative bacteria, including E. coli , Bacillus subtilis , Enterococcus faecium , Staphylococcus aureus , Klebsiella pneumoniae , Acinetobacter baumannii , Pseudomonas aeruginosa , and Enterobacter cloacae . GroEL/ES inhibitors were more effective at blocking the proliferation of Gram-positive bacteria, in particular S. aureus , where lead compounds exhibited antibiotic effects from the low-μM to mid-nM range. While several compounds inhibited the human HSP60/10 refolding cycle, some were able to selectively target the bacterial GroEL/ES system. Despite inhibiting HSP60/10, many compounds exhibited low to no cytotoxicity against human liver and kidney cell lines. Two lead candidates emerged from the panel, compounds 8 and 18 , that exhibit >50-fold selectivity for inhibiting S. aureus growth compared to liver or kidney cell cytotoxicity. Compounds 8 and 18 inhibited drug-sensitive and methicillin-resistant S. aureus strains with potencies comparable to vancomycin, daptomycin, and streptomycin, and are promising candidates to explore for validating the GroEL/ES chaperonin system as a viable antibiotic target. [ABSTRACT FROM AUTHOR]

[Display omitted] While many studies have established the importance of protein homeostasis in tumor progression, little effort has been made to examine the therapeutic potential of targeting the HSP60 chaperonin system. In healthy cells, HSP60 is localized to the mitochondrial matrix; however, emerging evidence indicates HSP60 can be over-expressed and mis-localized to the cytosol of cancer cells, which is hypothesized to promote tumor cell survival and proliferation. This opens a potential avenue to selectively target the aberrant HSP60 in the cytosol as a chemotherapeutic strategy. In the present work, we examined a series of bis -aryl-α,β-unsaturated ketone (ABK) HSP60 inhibitors for their ability to selectively target cancerous vs non-cancerous colon and intestine cells. We found that lead analogs inhibited migration and clonogenicity of cancer cells, with cytotoxicity correlating with the level of aberrant HSP60 in the cytosol. [ABSTRACT FROM AUTHOR]

Human mitochondria harbor a single type I chaperonin system that is generally thought to function via a unique single-ring intermediate. To date, no crystal structure has been published for any mammalian type I chaperonin complex. In this study, we describe the crystal structure of a football-shaped, double-ring human mitochondrial chaperonin complex at 3.15 Å, which is a novel intermediate, likely representing the complex in an early stage of dissociation. Interestingly, the mitochondrial chaperonin was captured in a state that exhibits subunit asymmetry within the rings and nucleotide symmetry between the rings. Moreover, the chaperonin tetradecamers show a different interring subunit arrangement when compared to GroEL. Our findings suggest that the mitochondrial chaperonins use a mechanism that is distinct from the mechanism of the well-studied Escherichia coli system. [ABSTRACT FROM AUTHOR]

Heat-shock protein (Hsp)10 is the co-chaperone for Hsp60 inside mitochondria, but it also resides outside the organelle. Variations in its levels and intracellular distribution have been documented in pathological conditions, e.g. cancer and chronic obstructive pulmonary disease (COPD). Here, we show that Hsp10 in COPD undergoes changes at the molecular and subcellular levels in bronchial cells from human specimens and derived cell lines, intact or subjected to stress induced by cigarette smoke extract (CSE). Noteworthy findings are: (i) Hsp10 occurred in nuclei of epithelial and lamina propria cells of bronchial mucosa from non-smokers and smokers; (ii) human bronchial epithelial (16HBE) and lung fibroblast (HFL-1) cells, in vitro, showed Hsp10 in the nucleus, before and after CSE exposure; (iii) CSE stimulation did not increase the levels of Hsp10 but did elicit qualitative changes as indicated by molecular weight and isoelectric point shifts; and (iv) Hsp10 nuclear levels increased after CSE stimulation in HFL-1, indicating cytosol to nucleus migration, and although Hsp10 did not bind DNA, it bound a DNA-associated protein.

Hsp10 and Hsp60 are important heat shock proteins (HSPs), which might be indispensable in the heat shock response and many other physiological processes. We obtained full-length cDNAs of genes hsp10 and hsp60 and classified their mRNA expression levels under thermal stress in the sea cucumber Apostichopus japonicus. Full-length hsp10 cDNA was 1528bp containing a 5′ untranslated region (UTR) of 83bp, a 3′ UTR of 1133bp and an open reading frame (ORF) of 312bp encoding 103 amino acid residues. Full-length hsp60 cDNA was 2560bp containing a 118-bp 5′ UTR, a 678-bp 3′ UTR and a 1764-bp ORF encoding 586 amino acid residues. The deduced amino acid sequences of Hsp10 and Hsp60 shared the highest identity with sequences of the sea urchin Strongylocentrotus purpuratus, and phylogenetic trees showed that the evolution of Hsp10 and Hsp60 was almost in accord with the evolution of species. Further analysis by real-time PCR showed that the expression of hsp10 and hsp60 mRNA was highly up-regulated at 26°C compared with other three groups (20, 22, 24°C), and their expression in the intestine was in a time-dependent manner at 26°C. The results suggested that hsp10 and hsp60 were involved in the heat-shock response in the sea cucumber A. japonicus. [ABSTRACT FROM AUTHOR]

Abstract: Objective: To investigate the effect of heat shock protein 10 (HSP10) on apoptosis induced by testosterone in granulosa cells (GCs) of mouse ovaries in order to define the possible roles of HSP10 in ovarian pathological development of polycystic ovarian syndrome (PCOS) and hyperandrogenic conditions. Study design: Cultured mouse ovarian GCs were treated with testosterone (10−5 mol/l). Apoptosis was assessed using flow cytometry, and proliferation was assessed using the MTT assay. HSP10 expression in the treated GCs was detected by real-time polymerase chain reaction (PCR). HSP10 gene was downregulated in the cultured GCs by AdCMV-H1-SiRNA/HSP10 or overexpressed by AdCMV-HSP10. PD98059 [phosphorylated ERK (p-ERK) inhibitor] was used to treat GCs to induce a high apoptosis index. Critical apoptotic factors and proliferation factors, including P-ERK, Bcl-2, Bax, caspase 9, caspase 3 and Ki67, were monitored by real-time reverse transcriptase PCR (RT-PCR) and Western blot. Results: Compared with the control group, the apoptosis index was higher (p <0.05) and HSP10 expression was lower (p <0.05) in the testosterone-treated groups. In the AdCMV-H1-SiRNA/HSP10-treated group, cell viability was decreased (p <0.05) and the cell cycle was arrested at G2. Expression of p-ERK, Bcl-2 and Ki67, and the Bcl-2:Bax ratio were lower, while expression of apoptotic factors, including Bax, caspase 9 and caspase 3, was higher (p <0.05). Compared with the control group, Bcl-2 expression in the GCs that overexpressed HSP10 was increased (p <0.05), while the reduction of p-ERK and Bcl-2 and the elevation of caspase 9 and caspase 3 induced by PD98059 were significantly suppressed (p <0.05). Conclusions: Hyperandrogenic conditions induced apoptosis of mouse GCs. Testosterone may have reduced HSP10 expression in GCs, leading to reduced Bcl-2 expression and increased Bax expression. [Copyright &y& Elsevier]

Abstract: Heat shock protein 10 (HSP10) gene of humphead snapper (Lutjanus sanguineus), designated as ByHSP10, was cloned by rapid amplification of cDNA ends (RACE) techniques with the primers designed from the known EST sequence identified from the subtracted cDNA library of the head kidney of humphead snapper. Sequence analysis showed the full length cDNA of ByHSP10 was 529bp, containing a 5′ terminal untranslated region (UTR) of 51bp, a 3′ terminal UTR of 181bp, and an open reading frame (ORF) of 297bp encoding a polypeptide of 99 amino acids. Based on the deduced amino acid sequence, the theoretical molecular mass of ByHSP10 was calculated to be 10.92kDa with an isoelectric point of 9.46. Moreover, chaperonins hsp10/cpn10 signature was found in the amino acids sequence of ByHSP10 by PredictProtein. BLAST analysis revealed that the amino acids of ByHSP10 had the highest homology of 88% compared with other HSP10s. Fluorescent real-time quantitative RT-PCR was used to examine the expression of ByHSP10 gene in eight kinds of tissues of humphead snapper after the challenge with Vibrio harveyi. There was a clear time-dependent expression pattern of ByHSP10 in head kidney, spleen and thymus after bacteria challenge. The expression of mRNA reached the maximum level at the time point of 9h, 6h and 24h, respectively and then returned to control level in 36h. The up-regulated mRNA expression of ByHSP10 in humphead snapper after bacteria challenge indicated that the HSP10 gene was inducible and might be involved in immune response. A phylogenetic tree was constructed based on the ORF nucleotide sequences of HSP10 for 30 species. The relatonships among them were generally in agreement with the traditional taxonomy which suggested that HSP10 genes could aid in the system classification research. [Copyright &y& Elsevier]

Objectives. To study the roles of heat shock proteins10 (HSP10) in the regulation of mouse ovarian granulose cell (GC) apoptosis, and to further define the possible roles of HSP10 in the development of polycystic ovary syndrome (PCOS). Methods. Mouse HSP10 small interfering RNA (siRNA) and recombinant adenoviruses overexpressing HSP10 were constructed and subsequently transfected into cultured mouse ovarian GCs. After an infection period of 48 h, the expression levels of the HSP10 gene in mouse GCs were confirmed by Western blot. The GCs were also assessed for apoptosis using flow cytometry and the TUNEL assay. Apoptosis of GCs overexpressing HSP10 was assessed by flow cytometry after cisplatin treatment. Results. Compared with control group, the expression of HSP10 was decreased in mouse GCs infected with AdCMV-siRNA/HSP10, whereas mouse GCs infected with AdCMV-HSP10 showed increased HSP10 expression p < 0.05. Knock-down of HSP10 in mouse GCs significantly increased apoptosis ( p < 0.05), whereas overexpression of HSP10 significantly suppressed apoptosis induced by cisplatin ( p < 0.05). Conclusion. In the present primary study, we have successfully employed recombinant adenovirus technologies to modulate HSP10 gene expression in mouse GCs, and examined the effects on apoptosis. Our experiments have demonstrated that knock-down of HSP10 induces apoptosis of mouse ovarian GCs, whereas overexpression of HSP10 suppresses apoptosis. These findings suggested that HSP10 may play a role in the regulation of apoptosis of mouse ovarian GCs. [ABSTRACT FROM AUTHOR]

Abstract: This article is about Hsp10 and its intracellular and extracellular forms focusing on the relationship of the latter with Early Pregnancy Factor and on their roles in cancer and immunity. Cellular physiology and survival are finely regulated and depend on the correct functioning of the entire set of proteins. Misfolded or unfolded proteins can cause deleterious effects and even cell death. The chaperonins Hsp10 and Hsp60 act together inside the mitochondria to assist protein folding. Recent studies demonstrated that these proteins have other roles inside and outside the cell, either together or independently of each other. For example, Hsp10 was found increased in the cytosol of different tumors (although in other tumors it was found decreased). Moreover, Hsp10 localizes extracellularly during pregnancy and is often indicated as Early Pregnancy Factor (EPF), which is released during the first stages of gestation and is involved in the establishment of pregnancy. Various reports show that extracellular Hsp10 and EPF modulate certain aspects of the immune response with anti-inflammatory effects in patients with autoimmune conditions improving clinically after treatment with recombinant Hsp10. Moreover, Hsp10 and EPF are involved in embryonic development, acting as a growth factor, and in cell proliferation/differentiation mechanisms. Therefore, it becomes evident that Hsp10 is not only a co-chaperonin, but an active player in its own right in various cellular functions. In this article, we present an overview of various aspects of Hsp10 and EPF as they participate in physiological and pathological processes such as the antitumor response and autoimmune diseases. [Copyright &y& Elsevier]

Objective. To study the possible roles of HSP10 in the follicular development. Methods. In this study, we examined the expression of HSP10 during the follicular development in human ovaries and cultured mouse follicles as well as its functional relevance with PCOS. Ovary tissues from normal adults (n = 3) were obtained with consents. Mouse early antral follicles (diameter: 220-250 μm) were cultured for 3 days in vitro. Western Blot and immunohistochemistry were used to determine the HSP10 expression and localisation during follicular development in vivo and in vitro. Results. HSP10 protein was detected only in oocytes from human preantral follicles, whereas in antral follicles, it was localised in oocytes, granulosa cells, theca cells and stroma cells. Furthermore, in cultured mouse antral follicles, a similar trend of HSP10 expression during follicle development was observed. Conclusion. HSP10 expression was increased as larger area and higher level of density during follicular development both in human and mouse follicles cultured in vitro. Our previous studies showed that HSP10 was highly expressed in normal ovaries compared with those from PCOS. The mouse early antral follicle culture approach may help to understand the role of HSP10 in pathophysiological development of PCOS. [ABSTRACT FROM AUTHOR]

Abstract: Antigen three-dimensional structure potentially controls presentation of CD4+ T-cell epitopes by limiting the access of proteolytic enzymes and MHC class II antigen-presenting proteins. The protease-sensitive mobile loops of Hsp10s from mycobacteria, Escherichia coli, and bacteriophage T4 (T4Hsp10) are associated with adjacent immunodominant helper T-cell epitopes, and a mobile-loop deletion in T4Hsp10 eliminated the protease sensitivity and the associated epitope immunodominance. In the present work, protease-sensitivity and epitope presentation was analyzed in a group of T4Hsp10 variants. Two mobile-loop sequence variants of T4Hsp10 were constructed by replacing different segments of the mobile loop with an irrelevant sequence from hen egg lysozyme. The variant proteins retained native-like structure, and the mobile loops retained protease sensitivity. Mobile-loop deletion and reconstruction affected the presentation of two epitopes according to whether the epitope was protease-independent or protease-dependent. The protease-independent epitope lies within the mobile loop, and the protease-dependent epitope lies in a well-ordered segment on the carboxy-terminal flank of the mobile loop. The results are consistent with a model for processing of the protease-dependent epitope in which an endoproteolytic nick in the mobile-loop unlocks T4Hsp10 three-dimensional structure, and then the epitope becomes available for binding to the MHC protein. [Copyright &y& Elsevier]

Molecular chaperones assist protein folding, and variations in their encoding genes may be disease-causing in themselves or influence the phenotypic expression of disease-associated or susceptibility-conferring variations in many different genes. We have screened three candidate patient groups for variations in the HSPD1 and HSPE1 genes encoding the mitochondrial Hsp60/Hsp10 chaperone complex: two patients with multiple mitochondrial enzyme deficiency, 61 sudden infant death syndrome cases (MIM: #272120), and 60 patients presenting with ethylmalonic aciduria carrying non-synonymous susceptibility variations in the ACADS gene (MIM: *606885 and #201470). Besides previously reported variations we detected six novel variations: two in the bidirectional promoter region, and one synonymous and three non-synonymous variations in the HSPD1 coding region. One of the non-synonymous variations was polymorphic in patient and control samples, and the rare variations were each only found in single patients and absent in 100 control chromosomes. Functional investigation of the effects of the variations in the promoter region and the non-synonymous variations in the coding region indicated that none of them had a significant impact. Taken together, our data argue against the notion that the chaperonin genes play a major role in the investigated diseases. However, the described variations may represent genetic modifiers with subtle effects. [ABSTRACT FROM AUTHOR]

Abstract: Infection, in particular by Chlamydia pneumoniae (Cp), has been associated with atherosclerosis and coronary heart disease. Immune reactions to heat shock proteins (HSPs) have been advocated to link infection to atherosclerosis and its acute sequelae based on molecular mimicry with host HSPs. We have here evaluated the role played by recombinant Cp-HSP60 and Cp-HSP10 for their ability to induce maturation of human monocyte-derived dendritic cells (MDDC) and T cell polarization. Cp-HSP60, but not Cp-HSP10, induced a strong MDCC maturation, as assessed by the expression of co-stimulatory molecules and other markers. Secretion of regulatory cytokines and enhancement of antigen presenting ability of mature (m)MDDC toward a clear T helper (Th) 1 pattern were also induced by Cp-HSP60. An analysis of the IL-12 cytokine family demonstrated that Cp-HSP60-matured MDDC were able to express p35 and p40 mRNA subunits to form IL-12, and p19 and p40 subunits to form IL-23. Thus, preferential Th1 polarization of immune response induced by Cp-HSP60-matured MDDC appears to be due to the concomitant expression of IL-12 and IL-23. Our data suggest that Cp-HSP60-matured DC may contribute to T-cell mediated immunopathology of atherosclerosis via a chronic stimulation of Th1 immune responses. [Copyright &y& Elsevier]

Abstract: In this study the prevalence of antibodies against the heat shock protein 10 (HSP10) of Chamydophila pneumoniae (CP) (as assessed by ELISA) in patients with coronary heart disease (CHD) and seropositive or seronegative to CP, as assessed by microimmunofluorescence (MIF), was investigated. The controls were age- and sex-matched healthy subjects. The HSP10 preparation used throughout this study was a 6-his-tagged recombinant protein preliminarily shown to be immunogenic in mice. Low level IgG reactivity against CP-HSP10 was detected in 19 out of 200 and 5 out of 100 CHD patients and controls, respectively. No IgM or IgA isotypes were found. Furthermore, there was no difference in the frequency or level of anti-HSP10 IgG between CP-positive and CP-negative sera either in patients (11/140=7.9% vs. 8/60=13%) or in healthy subjects (3/40=7.5% vs. 2/60=3.3%). Overall, our data indicate that CP-HSP10, at variance with CP-HSP60, to which it is genetically and physiologically linked, should not be regarded as a major expressed immunogen or a marker of infection by CP in CHD patients. [Copyright &y& Elsevier]