Myelin pathology: Involvement of molecular chaperones and the promise of chaperonotherapy

The process of axon myelination involves various proteins including molecular chaperones. Myelin alteration is a common feature in neurological diseases due to structural and functional abnormalities of one or more myelin proteins. Genetic proteinopathies may occur either in the presence of a normal chaperoning system, which is unable to assist the defective myelin protein in its folding and migration, or due to mutations in chaperone genes, leading to functional defects in assisting myelin maturation/migration. The latter are a subgroup of genetic chaperonopathies causing demyelination. In this brief review, we describe some paradigmatic examples pertaining to the chaperonins Hsp60 (HSPD1, or HSP60, or Cpn60) and CCT (chaperonin-containing TCP-1). Our aim is to make scientists and physicians aware of the possibility and advantages of classifying patients depending on the presence or absence of a chaperonopathy. In turn, this subclassification will allow the development of novel therapeutic strategies (chaperonotherapy) by using molecular chaperones as agents or targets for treatment

Chaperonopathies and Chaperonotherapy. Hsp60 as Therapeutic Target in Cancer: Potential Benefits and Risks.

In this minireview we focus on Hsp60 as a target for anticancer therapy. We discuss the new concepts of chaperonopathies and chaperonotherapy and present information on Hsp60 localization in the cell membrane of human tumor cells. We describe novel mechanisms for Hsp60 reaching the extracellular environment that involve membrane-associated stages, as well as data on anti-Hsp60 antibodies found in human sera, both in normal subjects and patients affected by autoimmune diseases. Finally, we discuss possible therapeutic applications of anti-Hsp60 antibodies in cancer treatment, evaluating also side effects on non-tumor cells. In conclusion, the way for investigating Hsp60-targeted anti-tumor therapy is open, at least for those tumors that express Hsp60 on its surface and/or secrete it outside the cell, as is the search for the molecular mechanisms involved in Hsp60 translocation from cytosol to cell membrane: elucidation of this mechanism will greatly facilitate the optimization of chaperonotherapy centered on Hsp60 with anti-tumor efficacy and minimal side effects

SARS-CoV-2 in patients with cancer: possible role of mimicry of human molecules by viral proteins and the resulting anti-cancer immunity

A few reports suggest that molecular mimicry can have a role in determining the more severe and deadly forms of COVID-19, inducing endothelial damage, disseminated intravascular coagulation, and multiorgan failure. Heat shock proteins/molecular chaperones can be involved in these molecular mimicry phenomena. However, tumor cells can display on their surface heat shock proteins/molecular chaperones that are mimicked by SARS-CoV-2 molecules (including the Spike protein), similarly to what happens in other bacterial or viral infections. Since molecular mimicry between SARS-CoV-2 and tumoral proteins can elicit an immune reaction in which antibodies or cytotoxic cells produced against the virus cross-react with the tumor cells, we want to prompt clinical studies to evaluate the impact of SARS-CoV-2 infection on prognosis and follow up of various forms of tumors. These topics, including a brief historical overview, are discussed in this paper

Alzheimer’s disease and molecular chaperones: Current knowledge and the future of chaperonotherapy

Background: Alzheimer’s disease (AD) is a dementia, a neurodegenerative condition, and a protein-misfolding disease or proteinopathy, characterized by protein deposits, extracellular plaques and intracellular neurofibrillary tangles, which contain the AD’s typical pathological proteins, abnormal [1]-amyloid and hyperphosphorylated tau, respectively, and are located predominantly in the cortex of the frontal, parietal, and temporal brain lobes. What is the role of molecular chaperones in AD? Data indicate that molecular chaperones, also known as Hsp, are involved in AD, probably displaying protective roles and/or acting as pathogenic factors as it occurs in chaperonopathies in which case AD would be suitable to chaperonotherapy. Hsp60, Hsp70, and Hsp90 can be augmented and overexpressed or diminished and downregulated in various situations in AD affected tissues and cells, indicating they are active during disease development and progression. Question: What is the role of molecular chaperones in AD? Data indicate that molecular chaperones, also known as Hsp, are involved in AD, probably displaying protective roles and/or acting as pathogenic factors as it occurs in chaperonopathies in which case AD would be suitable to chaperonotherapy. Objective: Investigate the role of Hsp in AD, focusing on Hsp60, Hsp70, and Hsp90. Method: Critical examination of published data. Results: Hsp60, Hsp70, and Hsp90 can be augmented and overexpressed or diminished and downregulated in various situations in AD affected tissues and cells, indicating they are active during disease development and progression. Conclusion and Perspectives: Notwithstanding that the roles and mechanisms of action of chaperones in AD are still incompletely understood, there is already enough evidence to encourage the development of therapeutic strategies targeting them, either to block their activity in case they promote disease progression or to boost their performance when they are protective. The latter is an example of positive chaperonotherapy, which also includes chaperone replacement via gene or protein administration. On the contrary, if a chaperone is found to help the disease, it has to be blocked or eliminated, which constitute modalities of negative chaperonotherapy

CD1A-positive cells and HSP60 (HSPD1) levels in keratoacanthoma and squamous cell carcinoma

CD1a is involved in presentation to the immune system of lipid antigen derived from tumor cells with subsequent T cell activation. Hsp60 is a molecular chaperone implicated in carcinogenesis by, for instance, modulating the immune reaction against the tumor. We have previously postulated a synergism between CD1a and Hsp60 as a key factor in the activation of an effective antitumor immune response in squamous epithelia. Keratoacantomas (KAs) are benign tumors that however can transform into squamous cell carcinomas (SCCs), but the reasons for this malignization are unknown. In a previous study, we found that CD1a-positive cells are significantly more numerous in KA than in SCC. In this study, we analyzed a series of KAs and SCCs by immunohistochemistry for CD1a and Hsp60. Our results show that the levels of both are significantly lower in KA than in SCC and support the hypothesis that KA may evolve towards SCC if there is a failure of the local modulation of the antitumor immune response. The data also show that immunohistochemistry for CD1a and Hsp60 can be of help in differential diagnosis between KAs and well-differentiated forms of SCC

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

The Molecular Anatomy of Human Hsp60 and its Similarity with that of Bacterial Orthologs and Acetylcholine Receptor Reveal a Potential Pathogenetic Role of Anti-Chaperonin Immunity in Myasthenia Gravis.

Heat-shock protein 60 (Hsp60) is ubiquitous and highly conserved being present in eukaryotes and prokaryotes, including pathogens. This chaperonin, although typically a mitochondrial protein, can also be found in other intracellular sites, extracellularly, and in circulation. Thus, it can signal the immune system and participate in the development of inflammation and immune reactions. Both phenomena can be elicited by human and foreign Hsp60 (e.g., bacterial GroEL), when released into the blood by infectious agents. Consequently, all these Hsp60 proteins become part of a complex autoimmune response characterized by multiple cross reactions because of their structural similarities. In this study, we demonstrate that Hsp60 proteins from humans and two common pathogens, Chlamydia trachomatis and Chlamydia pneumoniae, share various sequence segments of potentially highly immunogenic epitopes with acetylcholine receptor α1 subunit (AChRα1). The structural data indicate that AChRα1 antibodies, implicated in the pathogenesis of myasthenia gravis, could very well be elicited and/or maintained by self- and/or bacterial Hsp60

Functions and Therapeutic Potential of Extracellular Hsp60, Hsp70, and Hsp90 in Neuroinflammatory Disorders

Neuroinflammation is implicated in central nervous system (CNS) diseases, but the molecular mechanisms involved are poorly understood. Progress may be accelerated by developing a comprehensive view of the pathogenesis of CNS disorders, including the immune and the chaperone systems (IS and CS). The latter consists of the molecular chaperones; cochaperones; and chaperone cofactors, interactors, and receptors of an organism and its main collaborators in maintaining protein homeostasis (canonical function) are the ubiquitin-proteasome system and chaperone-mediated autophagy. The CS has also noncanonical functions, for instance, modulation of the IS with induction of proinflammatory cytokines. This deserves investigation because it may be at the core of neuroinflammation, and elucidation of its mechanism will open roads toward developing efficacious treatments centered on molecular chaperones (i.e., chaperonotherapy). Here, we discuss information available on the role of three members of the CS-heat shock protein (Hsp)60, Hsp70, and Hsp90-in IS modulation and neuroinflammation. These three chaperones occur intra- and extracellularly, with the latter being the most likely involved in neuroinflammation because they can interact with the IS. We discuss some of the interactions, their consequences, and the molecules involved but many aspects are still incompletely elucidated, and we hope that this review will encourage research based on the data presented to pave the way for the development of chaperonotherapy. This may consist of blocking a chaperone that promotes destructive neuroinflammation or replacing or boosting a defective chaperone with cytoprotective activity against neurodegeneration

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