A Novel CCT5 Missense Variant Associated with Early Onset Motor Neuropathy.

Diseases associated with acquired or genetic defects in members of the chaperoning system (CS) are increasingly found and have been collectively termed chaperonopathies. Illustrative instances of genetic chaperonopathies involve the genes for chaperonins of Groups I (e.g., Heat shock protein 60, Hsp60) and II (e.g., Chaperonin Containing T-Complex polypeptide 1, CCT). Examples of the former are hypomyelinating leukodystrophy 4 (HLD4 or MitCHAP60) and hereditary spastic paraplegia (SPG13). A distal sensory mutilating neuropathy has been linked to a mutation [p.(His147Arg)] in subunit 5 of the CCT5 gene. Here, we describe a new possibly pathogenic variant [p.(Leu224Val)] of the same subunit but with a different phenotype. This yet undescribed disease affects a girl with early onset demyelinating neuropathy and a severe motor disability. By whole exome sequencing (WES), we identified a homozygous CCT5 c.670C>G p.(Leu224Val) variant in the CCT5 gene. In silico 3D-structure analysis and bioinformatics indicated that this variant could undergo abnormal conformation and could be pathogenic. We compared the patient's clinical, neurophysiological and laboratory data with those from patients carrying p.(His147Arg) in the equatorial domain. Our patient presented signs and symptoms absent in the p.(His147Arg) cases. Molecular dynamics simulation and modelling showed that the Leu224Val mutation that occurs in the CCT5 intermediate domain near the apical domain induces a conformational change in the latter. Noteworthy is the striking difference between the phenotypes putatively linked to mutations in the same CCT subunit but located in different structural domains, offering a unique opportunity for elucidating their distinctive roles in health and disease.

The Interplay between Glioblastoma Cells and Tumor Microenvironment: New Perspectives for Early Diagnosis and Targeted Cancer Therapy.

Glioblastoma multiforme (GBM) stands out as the most tremendous brain tumor, constituting 60% of primary brain cancers, accompanied by dismal survival rates. Despite advancements in research, therapeutic options remain limited to chemotherapy and surgery. GBM molecular heterogeneity, the intricate interaction with the tumor microenvironment (TME), and non-selective treatments contribute to the neoplastic relapse. Diagnostic challenges arise from GBM advanced-stage detection, necessitating the exploration of novel biomarkers for early diagnosis. Using data from the literature and a bioinformatic tool, the current manuscript delineates the molecular interplay between human GBM, astrocytes, and myeloid cells, underscoring selected protein pathways belonging to astroglia and myeloid lineage, which can be considered for targeted therapies. Moreover, the pivotal role of extracellular vesicles (EVs) in orchestrating a favorable microenvironment for cancer progression is highlighted, suggesting their utility in identifying biomarkers for GBM early diagnosis.

scFv-oligopeptide chaperoning system-assisted on-column refolding and purification of human muscle creatine kinase from inclusion bodies.

The formation of inclusion bodies in bacterial hosts poses a major challenge for the large-scale recovery of bioactive proteins. The process of obtaining bioactive protein from inclusion bodies is labor intensive, and the yields of recombinant protein are often low. Here, we describe a novel method for the renaturation and purification of inclusion bodies. This method combines a scFv-oligopeptide chaperoning system and an on-column refolding system to help refold human muscle creatine kinase (HCK) inclusion bodies. This method could significantly increase the activity recovery of denatured HCK inclusion bodies and provides an effective method for the production of bioactive proteins from inclusion bodies.

Missense Mutations of Human Hsp60: A Computational Analysis to Unveil Their Pathological Significance.

Two chaperonopathies have been linked to mutations in the human hsp60 (hHsp60; HSPD1) gene, but other existing variants might cause diseases, even if there is no comprehensive information about this possibility. To fill this vacuum, which might be at the basis of misdiagnoses or simply ignorance of chaperonopathies in patients who would benefit by proper identification of their ailments, we searched the sequenced human genomes available in public databases to determine the range of missense mutations in the single hsp60 gene. A total of 224 missense mutations were identified, including those already characterized. Detailed examination of these mutations was carried out to assess their possible impact on protein structure-function, considering: (a) the properties of individual amino acids; (b) the known functions of the amino acids in the human Hsp60 and/or in the highly similar bacterial ortholog GroEL; (c) the location of the mutant amino acids in the monomers and oligomers; and (d) structure-function relationships inferred from crystal structures. And we also applied a bioinformatics tool for predicting the impact of mutations on proteins. A portion of these genetic variants could have a deleterious impact on protein structure-function, but have not yet been associated with any pathology. Are these variants causing disease with mild clinical manifestations and are, therefore, being overlooked? Or are they causing overt disease, which is misdiagnosed? Our data indicate that more chaperonopathies might occur than is currently acknowledged and that awareness of chaperonopathies among medical personnel will increase their detection and improve patient management.

Molecular chaperones in tumors of salivary glands.

The salivary glands are key components of the mouth and play a central role in its physiology. Their importance may be appreciated considering their number, occurrence in pairs, and distribution in the mouth: two parotids, two submandibular, two sublingual, and many other small ones scattered throughout the mouth. They produce saliva, without which ingestion of non-liquid nutrients and speech would be practically impossible. Nevertheless, the physiology and pathology of salivary glands are poorly understood. For instance, tumors of salivary glands occur, and their incidence is on the rise, but their etiology and pathogenesis are virtually unknown, although some risk factors have been identified. Likewise, the role of the chaperoning system in the development, normal functioning, and pathology, including carcinogenesis, remains to be determined. This scarcity of basic knowledge impedes progress in diagnosis, disease monitoring, and therapeutics of salivary gland tumors. We are currently involved in examining the chaperoning system of human salivary glands and we performed a search of the literature to determine what has been reported relating to oncology. We found data pertaining to six components of the chaperone system, namely HSP27, HSP60, HSP70, HSP84, HSP86, and GRP78, and to another HSP, the heme-oxygenase H-O1, also named HSP32, which does not belong in the chaperoning system but seemed to have potential as a biomarker for diagnostic purposes as much as the HSP/chaperones mentioned above. The reported quantitative variations of the six chaperones were distinctive enough to distinguish malignant from benign tumors, suggesting that these molecules hold potential as biomarkers useful in differential diagnosis. Also, the quantitative variations described accompanying tumor development, as observed in cancers of other organs, encourages research to elucidate whether chaperones play a role in the initiation and/or progression of salivary gland tumors.

Hsp60 as a Novel Target in IBD Management: A Prospect.

Inflammatory bowel disease (IBD) encompasses various pathological conditions similar but distinct that share a multifactorial etiology, including involvement of the intestinal barrier function, the immune system, and intestinal microorganisms. Hsp60 is a chaperonin component of the chaperoning system, present in all cells and tissues, including the intestine. It plays important roles in cell physiology outside and inside mitochondria, its canonical place of residence. However, Hsp60 can also be pathogenic in many conditions, the Hsp60 chaperonopathies, possibly including IBD. The various clinico-pathological types of IBD have a complicated mix of causative factors, among which Hsp60 can be considered a putatively important driver of events and could play an etiopathogenic role. This possibility is discussed in this review. We also indicate that Hsp60 can be a biomarker useful in disease diagnosing and monitoring and, if found active in pathogenesis, should become a target for developing new therapies. The latter are particularly needed to alleviate patient suffering and to prevent complications, including colon cancer.

Depleted uranium induces human carcinogenesis involving the immune and chaperoning systems: Realities and working hypotheses.

Cancer is caused by a combination of factors, genetic, epigenetics and environmental. Among the latter, environmental pollutants absorbed by contact, inhalation, or ingestion are major proven or suspected culprits. Depleted uranium (DU) is one of them directly pertinent to the military and civilians working in militarized areas. It is considered a weak carcinogen but its implication in cancer development in exposed individuals is supported by various data. Since not all subjects exposed to DU develop cancer, it is likely that DU-dependent carcinogenesis requires cofactors, such as genetic predisposition and deficiencies of the chaperoning and immune systems. It is of the essence to adopt every possible protective measure as well as performing careful screening for early diagnosis to protect the military that work in war areas in which weapons with DU are, or have been, used. These topics are discussed here, along with a proposed working hypothesis for investigating the pathophysiology of DU-related carcinogenesis, including the possible role of the chaperoning system.