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Chierichetti M, Cerretani M, Ciammaichella A, Crippa V, Rusmini P, Ferrari V, Tedesco B, Casarotto E, Cozzi M, Mina F, Pramaggiore P, Galbiati M, Piccolella M, Bresciani A, Cristofani R, Poletti A. Identification of HSPB8 modulators counteracting misfolded protein accumulation in neurodegenerative diseases. Life Sci 2022; 322:121323. [PMID: 36574942 DOI: 10.1016/j.lfs.2022.121323] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Revised: 12/17/2022] [Accepted: 12/20/2022] [Indexed: 12/25/2022]
Abstract
AIMS The small Heat Shock Protein B8 (HSPB8) is the core component of the chaperone-assisted selective autophagy (CASA) complex. This complex selectively targets, transports, and tags misfolded proteins for their recognition by autophagic receptors and insertion into autophagosome for clearance. CASA is essential to maintain intracellular proteostasis, especially in heart, muscle, and brain often exposed to various types of cell stresses. In neurons, HSPB8 protects against neurotoxicity caused by misfolded proteins in several models of neurodegenerative diseases; by facilitating autophagy, HSPB8 assists misfolded protein degradation also counteracting proteasome overwhelming and inhibition. MATERIALS AND METHODS To enhance HSPB8 protective activity, we screened a library of approximately 120,000 small molecules to identify compounds capable of increasing HSPB8 gene transcription, translation, or protein stability. We found 83 compounds active in preliminary dose-response assays and further classified them in 19 chemical classes by medicinal chemists' visual inspection. Of these 19 prototypes, 14 induced HSPB8 mRNA and protein levels in SH-SY5Y cells. KEY FINDINGS Out of these 14, 3 successfully reduced the aggregation propensity of a disease-associated mutant misfolded Superoxide Dismutase 1 (SOD1) protein in a flow cytometry-based "aggregation assay" [Flow cytometric analysis of Inclusions and Trafficking" (FloIT)] and induced the expression (mRNA and protein) of some autophagy receptors. Notably, the 3 hits were inactive in HSPB8-depleted cells, confirming that their protective activity is mediated by and requires HSPB8. SIGNIFICANCE Thus, these compounds may be highly relevant for a therapeutic approach in several human disorders, including neurodegenerative diseases, in which enhancement of CASA exerts beneficial activities.
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Affiliation(s)
- Marta Chierichetti
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Milan, Italy
| | - Mauro Cerretani
- Department of Translational and Discovery Research, IRBM S.p.A., Via Pontina Km 30,600, 00071 Pomezia, Roma, Italy
| | - Alina Ciammaichella
- Department of Drug Discovery, IRBM S.p.A., Via Pontina Km 30,600, 00071 Pomezia, Roma, Italy
| | - Valeria Crippa
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Milan, Italy
| | - Paola Rusmini
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Milan, Italy
| | - Veronica Ferrari
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Milan, Italy
| | - Barbara Tedesco
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Milan, Italy; Unit of Medical Genetics and Neurogenetics, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Elena Casarotto
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Milan, Italy
| | - Marta Cozzi
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Milan, Italy
| | - Francesco Mina
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Milan, Italy
| | - Paola Pramaggiore
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Milan, Italy
| | - Mariarita Galbiati
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Milan, Italy
| | - Margherita Piccolella
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Milan, Italy
| | - Alberto Bresciani
- Department of Translational and Discovery Research, IRBM S.p.A., Via Pontina Km 30,600, 00071 Pomezia, Roma, Italy
| | - Riccardo Cristofani
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Milan, Italy.
| | - Angelo Poletti
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Milan, Italy.
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Qu H, Feldman AM, Hakonarson H. Genetics of BAG3: A Paradigm for Developing Precision Therapies for Dilated Cardiomyopathies. J Am Heart Assoc 2022; 11:e027373. [PMID: 36382946 PMCID: PMC9851466 DOI: 10.1161/jaha.122.027373] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Nonischemic dilated cardiomyopathy is a common form of heart muscle disease in which genetic factors play a critical etiological role. In this regard, both rare disease-causing mutations and common disease-susceptible variants, in the Bcl-2-associated athanogene 3 (BAG3) gene have been reported, highlighting the critical role of BAG3 in cardiomyocytes and in the development of dilated cardiomyopathy. The phenotypic effects of the BAG3 mutations help investigators understand the structure and function of the BAG3 gene. Indeed, we report herein that all of the known pathogenic/likely pathogenic variants affect at least 1 of 3 protein functional domains, ie, the WW domain, the second IPV (Ile-Pro-Val) domain, or the BAG domain, whereas none of the missense nontruncating pathogenic/likely pathogenic variants affect the proline-rich repeat (PXXP) domain. A common variant, p.Cys151Arg, associated with reduced susceptibility to dilated cardiomyopathy demonstrated a significant difference in allele frequencies among diverse human populations, suggesting evolutionary selective pressure. As BAG3-related therapies for heart failure move from the laboratory to the clinic, the ability to provide precision medicine will depend in large part on having a thorough understanding of the potential effects of both common and uncommon genetic variants on these target proteins. The current review article provides a roadmap that investigators can utilize to determine the potential interactions between a patient's genotype, their phenotype, and their response to therapeutic interventions with both gene delivery and small molecules.
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Affiliation(s)
- Hui‐Qi Qu
- The Center for Applied Genomics, Children’s Hospital of PhiladelphiaPhiladelphiaPA
| | - Arthur M. Feldman
- Department of Medicine, Division of CardiologyThe Lewis Katz School of Medicine at Temple UniversityPhiladelphiaPA,The Center for Neurovirology and Gene EditingThe Lewis Katz School of Medicine at Temple UniversityPhiladelphiaPA
| | - Hakon Hakonarson
- The Center for Applied Genomics, Children’s Hospital of PhiladelphiaPhiladelphiaPA,Department of Pediatrics, The Perelman School of MedicineUniversity of PennsylvaniaPhiladelphiaPA,Division of Human GeneticsChildren’s Hospital of PhiladelphiaPhiladelphiaPA,Division of Pulmonary MedicineChildren’s Hospital of PhiladelphiaPhiladelphiaPA,Faculty of MedicineUniversity of IcelandReykjavikIceland
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The Role of Small Heat Shock Proteins in Protein Misfolding Associated Motoneuron Diseases. Int J Mol Sci 2022; 23:ijms231911759. [PMID: 36233058 PMCID: PMC9569637 DOI: 10.3390/ijms231911759] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Revised: 09/29/2022] [Accepted: 09/30/2022] [Indexed: 11/17/2022] Open
Abstract
Motoneuron diseases (MNDs) are neurodegenerative conditions associated with death of upper and/or lower motoneurons (MNs). Proteostasis alteration is a pathogenic mechanism involved in many MNDs and is due to the excessive presence of misfolded and aggregated proteins. Protein misfolding may be the product of gene mutations, or due to defects in the translation process, or to stress agents; all these conditions may alter the native conformation of proteins making them prone to aggregate. Alternatively, mutations in members of the protein quality control (PQC) system may determine a loss of function of the proteostasis network. This causes an impairment in the capability to handle and remove aberrant or damaged proteins. The PQC system consists of the degradative pathways, which are the autophagy and the proteasome, and a network of chaperones and co-chaperones. Among these components, Heat Shock Protein 70 represents the main factor in substrate triage to folding, refolding, or degradation, and it is assisted in this task by a subclass of the chaperone network, the small heat shock protein (sHSPs/HSPBs) family. HSPBs take part in proteostasis by bridging misfolded and aggregated proteins to the HSP70 machinery and to the degradative pathways, facilitating refolding or clearance of the potentially toxic proteins. Because of its activity against proteostasis alteration, the chaperone system plays a relevant role in the protection against proteotoxicity in MNDs. Here, we discuss the role of HSPBs in MNDs and which HSPBs may represent a valid target for therapeutic purposes.
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Muranova LK, Shatov VM, Gusev NB. Role of Small Heat Shock Proteins in the Remodeling of Actin Microfilaments. BIOCHEMISTRY. BIOKHIMIIA 2022; 87:800-811. [PMID: 36171660 DOI: 10.1134/s0006297922080119] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Revised: 04/28/2022] [Accepted: 04/28/2022] [Indexed: 06/16/2023]
Abstract
Small heat shock proteins (sHsps) play an important role in the maintenance of proteome stability and, particularly, in stabilization of the cytoskeleton and cell contractile apparatus. Cell exposure to different types of stress is accompanied by the translocation of sHsps onto actin filaments; therefore, it is commonly believed that the sHsps are true actin-binding proteins. Investigations of last years have shown that this assumption is incorrect. Stress-induced translocation of sHsp to actin filaments is not the result of direct interaction of these proteins with intact actin, but results from the chaperone-like activity of sHsps and their interaction with various actin-binding proteins. HspB1 and HspB5 interact with giant elastic proteins titin and filamin thus providing an integrity of the contractile apparatus and its proper localization in the cell. HspB6 binds to the universal adapter protein 14-3-3 and only indirectly affects the structure of actin filament. HspB7 interacts with filamin C and controls actin filament assembly. HspB8 forms tight complex with the universal regulatory and adapter protein Bag3 and participates in the chaperone-assisted selective autophagy (CASA) of actin-binding proteins (e.g., filamin), as well as in the actin-depending processes taking place in mitoses. Hence, the mechanisms of sHsp participation in the maintenance of the contractile apparatus and cytoskeleton are much more complicated and diverse than it has been postulated earlier and are not limited to direct interactions of sHsps with actin. The old hypothesis on the direct binding of sHsps to intact actin should be revised and further detailed investigation on the sHsp interaction with minor proteins participating in the formation and remodeling of actin filaments is required.
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Affiliation(s)
- Lydia K Muranova
- Faculty of Biology, Lomonosov Moscow State University, Moscow, 119991, Russia
| | - Vladislav M Shatov
- Faculty of Biology, Lomonosov Moscow State University, Moscow, 119991, Russia
| | - Nikolai B Gusev
- Faculty of Biology, Lomonosov Moscow State University, Moscow, 119991, Russia.
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