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Mattii L, Moscato S, Ippolito C, Polizzi E, Novo G, Zucchi R, De Caterina R, Ghelardoni S, Madonna R. Empagliflozin mitigates ponatinib-induced cardiotoxicity by restoring the connexin 43-autophagy pathway. Biomed Pharmacother 2024; 178:117278. [PMID: 39116784 DOI: 10.1016/j.biopha.2024.117278] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2024] [Revised: 08/02/2024] [Accepted: 08/05/2024] [Indexed: 08/10/2024] Open
Abstract
BACKGROUND Empagliflozin (EMPA), a selective sodium-glucose cotransporter type 2 (SGLT2) inhibitor, has been shown to reduce major adverse cardiovascular events in patients with heart failure of different etiologies, although the underlying mechanism still remains unclear. Ponatinib (PON) is a multi-tyrosine kinase inhibitor successfully used against myeloid leukemia and other human malignancies, but its cardiotoxicity remains worrisome. Cardiac connexins (Cxs) are both substrates and regulators of autophagy and responsible for proper heart function. Alteration in connexin expression and localization have been described in patients with heart failure. AIMS To assess whether EMPA can mitigate PON-induced cardiac dysfunction by restoring the connexin 43-autophagy pathway. METHODS AND RESULTS Male C57BL/6 mice, randomized into four treatment groups (CNTRL, PON, EMPA, PON+EMPA) for 28 days, showed increased autophagy, decreased Cx43 expression as well as Cx43 lateralization, and attenuated systo-diastolic cardiac dysfunction after treatment with EMPA and PON compared with PON alone. Compared with CNTRL (DMSO), cardiomyocyte-differentiated H9c2 (dH9c2) cells treated with PON showed significantly reduced cell viability to approximately 20 %, decreased autophagy, increased cell senescence and reduced DNA binding activity of serum response factor (SRF) to serum response elements (SRE), which were paralleled by reduction in cardiac actin expression. Moreover, PON induced a significant increase of Cx43 protein and its S368-phosphorylated form (pS368-Cx43), as well as their displacement from the plasma membrane to the perinuclear and nuclear cellular region. All these effects were reverted by EMPA. CONCLUSION EMPA attenuates PON-induced cardiotoxicity by reducing senescence, enhancing the SRE-SRF binding and restoring the connexin 43-autophagy pathway. This effect may pave the way to use of SGLT2 inhibitors in attenuating tyrosine-kinase inhibitor cardiotoxicity.
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Affiliation(s)
- Letizia Mattii
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - Stefania Moscato
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - Chiara Ippolito
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - Enza Polizzi
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - Giuseppina Novo
- Department of Health Promotion, Mother and Child Care, Internal Medicine and Medical Specialties, University of Palermo, Palermo, Italy
| | - Riccardo Zucchi
- Department of Pathology, Laboratory of Biochemistry, University of Pisa, Italy
| | | | - Sandra Ghelardoni
- Department of Pathology, Laboratory of Biochemistry, University of Pisa, Italy
| | - Rosalinda Madonna
- Department of Pathology, Cardiology Division, University of Pisa, Pisa, Italy.
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2
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Nikoo MH, Hatamnejad MR, Emkanjoo Z, Arjangzadeh A, Motahari Moadab M, Bazrafshan M, Bazrafshan Drissi H. The association between GJB2 gene (producing Cx26 protein) and the ventricular storm: A case report. ARYA ATHEROSCLEROSIS 2024; 20:1-7. [PMID: 39170815 PMCID: PMC11335029 DOI: 10.48305/arya.2023.11842.0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Accepted: 05/10/2023] [Indexed: 08/23/2024]
Abstract
BACKGROUND A structural heart disease or functional electrical abnormalities can cause an electrical storm. CASE PRESENTATION We present a young boy with an electrical storm who had no cardiac risk factors and a positive family history of sudden cardiac death. The stepwise diagnostic approach was ineffective in determining previously known causes as the origin of the electrical storm. However, whole-exome sequencing (with Next Generation Illumina Sequencing) revealed a mutation in the GJB2 (NM_004004:exon2:c.G71A:p.W24X) gene. CONCLUSION A mutation in the GJB2 gene, which forms the connexin 26 protein, a crucial component of the myocytes' intercalated disc of gap junction complex between the myocytes, results in an abnormal electrical cell-by-cell conductance, and, eventually, ventricular storm. General anesthesia was used to control the storm, and intracardiac pacing was fruitful in ceasing the subsequent VT storms.
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Affiliation(s)
- Mohammad Hossein Nikoo
- Non-Communicable Disease Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | | | - Zahra Emkanjoo
- Rajaie Cardiovascular, Medical and Research Center, Tehran, Iran
| | - Alireza Arjangzadeh
- Department of Cardiology Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Mehdi Motahari Moadab
- Department of Cardiology Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Mehdi Bazrafshan
- Faculty of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
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3
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Falleni A, Moscato S, Fulvio G, Polizzi E, Bernardeschi M, Bianchi F, Donati V, Cabiati M, Ippolito C, Del Ry S, Baldini C, Mattii L. Connexin Expression in Human Minor Salivary Glands: An Immunohistochemical Microscopy Study. Molecules 2022; 27:molecules27185926. [PMID: 36144660 PMCID: PMC9505306 DOI: 10.3390/molecules27185926] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Revised: 09/02/2022] [Accepted: 09/08/2022] [Indexed: 11/25/2022] Open
Abstract
Connexins (Cxs) are transmembrane proteins involved in the formation of hemichannels and gap junctions (GJs). GJs are involved in various physiological functions, including secretion in glandular tissue. It has been demonstrated that Cx26, Cx32, and Cx43 are mainly expressed in glands, but no data are available in human salivary glands to date. The aim of our study was to investigate the presence and the localization of Cxs in human minor labial salivary glands. Immunofluorescence and immunoelectron microscopy were employed to evaluate the Cx26, Cx32, and Cx43 protein in human labial salivary gland biopsies (hLSGBs). RT-PCR was also used to detect their mRNA expression. Cx expression was found at both the mRNA and protein levels in all hLSGBs analysed. Cxs were observed at the level of the duct and acinar cells, as well as in myoepithelial cells. The localization of the three Cx types was very similar, suggesting colocalization of these Cxs in the same connexons. These results demonstrated the presence of Cxs in human salivary glands for the first time. Moreover, the few samples with primary Sjögren’s Syndrome analysed only by immunofluorescence showed an alteration of the Cx expression, indicating that these proteins could be involved in salivary gland dysfunctions.
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Affiliation(s)
- Alessandra Falleni
- Department of Clinical and Experimental Medicine, University of Pisa, 56126 Pisa, Italy
- Correspondence: (A.F.); (L.M.); Tel.: +39-050-221-9106 (A.F.); +39-050-221-8615 (L.M.)
| | - Stefania Moscato
- Department of Clinical and Experimental Medicine, University of Pisa, 56126 Pisa, Italy
| | - Giovanni Fulvio
- Department of Clinical and Experimental Medicine, University of Pisa, 56126 Pisa, Italy
| | - Enza Polizzi
- Department of Clinical and Experimental Medicine, University of Pisa, 56126 Pisa, Italy
| | | | - Francesco Bianchi
- Department of Clinical and Experimental Medicine, University of Pisa, 56126 Pisa, Italy
| | - Valentina Donati
- Pathological Anatomy Unit, Azienda Ospedaliero-Universitaria Pisana, 56126 Pisa, Italy
| | - Manuela Cabiati
- Institute of Clinical Physiology (IFC), National Research Council (CNR), 56124 Pisa, Italy
| | - Chiara Ippolito
- Department of Clinical and Experimental Medicine, University of Pisa, 56126 Pisa, Italy
| | - Silvia Del Ry
- Institute of Clinical Physiology (IFC), National Research Council (CNR), 56124 Pisa, Italy
| | - Chiara Baldini
- Department of Clinical and Experimental Medicine, University of Pisa, 56126 Pisa, Italy
| | - Letizia Mattii
- Department of Clinical and Experimental Medicine, University of Pisa, 56126 Pisa, Italy
- Correspondence: (A.F.); (L.M.); Tel.: +39-050-221-9106 (A.F.); +39-050-221-8615 (L.M.)
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4
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Subcellular Localization of Connexin 26 in Cardiomyocytes and in Cardiomyocyte-Derived Extracellular Vesicles. Molecules 2021; 26:molecules26216726. [PMID: 34771134 PMCID: PMC8587102 DOI: 10.3390/molecules26216726] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Revised: 10/26/2021] [Accepted: 11/03/2021] [Indexed: 12/13/2022] Open
Abstract
Connexins (Cxs) are a family of membrane-spanning proteins, expressed in vertebrates and named according to their molecular weight. They are involved in tissue homeostasis, and they function by acting at several communication levels. Cardiac Cxs are responsible for regular heart function and, among them, Cx26 and Cx43 are widely expressed throughout the heart. Cx26 is present in vessels, as well as in cardiomyocytes, and its localization is scattered all over the cell aside from at the intercalated discs as is the case for the other cardiac Cxs. However, having been found in cardiomyocytes only recently, both its subcellular localization and its functional characterization in cardiomyocytes remain poorly understood. Therefore, in this study we aimed to obtain further data on the localization of Cx26 at the subcellular level. Our TEM immunogold analyses were performed on rat heart ventricles and differentiated H9c2 cardiac cell sections as well as on differentiated H9c2 derived extracellular vesicles. The results confirmed the absence of Cx26 at intercalated discs and showed the presence of Cx26 at the level of different subcellular compartments. The peculiar localization at the level of extracellular vesicles suggested a specific role for cardiac Cx26 in inter-cellular communication in an independent gap junction manner.
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5
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The Autophagy-Related Organelle Autophagoproteasome Is Suppressed within Ischemic Penumbra. Int J Mol Sci 2021; 22:ijms221910364. [PMID: 34638703 PMCID: PMC8508911 DOI: 10.3390/ijms221910364] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Revised: 09/22/2021] [Accepted: 09/24/2021] [Indexed: 01/18/2023] Open
Abstract
The peri-infarct region, which surrounds the irreversible ischemic stroke area is named ischemic penumbra. This term emphasizes the borderline conditions for neurons placed within such a critical region. Area penumbra separates the ischemic core, where frank cell loss occurs, from the surrounding healthy brain tissue. Within such a brain region, nervous matter, and mostly neurons are impaired concerning metabolic conditions. The classic biochemical marker, which reliably marks area penumbra is the over-expression of the heat shock protein 70 (HSP70). However, other proteins related to cell clearing pathways are modified within area penumbra. Among these, autophagy proteins like LC3 increase in a way, which recapitulates Hsp70. In contrast, components, such as P20S, markedly decrease. Despite apparent discrepancies, the present study indicates remarkable overlapping between LC3 and P20S redistribution within area penumbra. In fact, the amount of both proteins is markedly reduced within vacuoles. Specifically, a massive loss of LC3 + P20S immuno-positive vacuoles (autophagoproteasomes) is reported here. This represents the most relevant sub-cellular alteration here described in cell clearing pathways within area penumbra. The functional significance of these findings remains to be determined and it will take a novel experimental stream to decipher the fine-tuning of such a phenomenon.
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6
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Martins-Marques T. Connecting different heart diseases through intercellular communication. Biol Open 2021; 10:bio058777. [PMID: 34494646 PMCID: PMC8443862 DOI: 10.1242/bio.058777] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2021] [Accepted: 07/12/2021] [Indexed: 12/22/2022] Open
Abstract
Well-orchestrated intercellular communication networks are pivotal to maintaining cardiac homeostasis and to ensuring adaptative responses and repair after injury. Intracardiac communication is sustained by cell-cell crosstalk, directly via gap junctions (GJ) and tunneling nanotubes (TNT), indirectly through the exchange of soluble factors and extracellular vesicles (EV), and by cell-extracellular matrix (ECM) interactions. GJ-mediated communication between cardiomyocytes and with other cardiac cell types enables electrical impulse propagation, required to sustain synchronized heart beating. In addition, TNT-mediated organelle transfer has been associated with cardioprotection, whilst communication via EV plays diverse pathophysiological roles, being implicated in angiogenesis, inflammation and fibrosis. Connecting various cell populations, the ECM plays important functions not only in maintaining the heart structure, but also acting as a signal transducer for intercellular crosstalk. Although with distinct etiologies and clinical manifestations, intercellular communication derailment has been implicated in several cardiac disorders, including myocardial infarction and hypertrophy, highlighting the importance of a comprehensive and integrated view of complex cell communication networks. In this review, I intend to provide a critical perspective about the main mechanisms contributing to regulate cellular crosstalk in the heart, which may be considered in the development of future therapeutic strategies, using cell-based therapies as a paradigmatic example. This Review has an associated Future Leader to Watch interview with the author.
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Affiliation(s)
- Tania Martins-Marques
- Univ Coimbra, Coimbra Institute for Clinical and Biomedical Research (iCBR), Faculty of Medicine, 3000-548 Coimbra, Portugal
- Univ Coimbra, Center for Innovative Biomedicine and Biotechnology (CIBB), 3004-504 Coimbra, Portugal
- Clinical Academic Centre of Coimbra (CACC), 3004-561 Coimbra, Portugal
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7
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Ngezahayo A, Ruhe FA. Connexins in the development and physiology of stem cells. Tissue Barriers 2021; 9:1949242. [PMID: 34227910 DOI: 10.1080/21688370.2021.1949242] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Abstract
Connexins (Cxs) form gap junction (GJ) channels linking vertebrate cells. During embryogenesis, Cxs are expressed as early as the 4-8 cell stage. As cells differentiate into pluripotent stem cells (PSCs) and during gastrulation, the Cx expression pattern is adapted. Knockdown of Cx43 and Cx45 does not interfere with embryogenic development until the blastula stage, questioning the role of Cxs in PSC physiology and development. Studies in cultivated and induced PSCs (iPSCs) showed that Cx43 is essential for the maintenance of self-renewal and the expression of pluripotency markers. It was found that the role of Cxs in PSCs is more related to regulation of transcription or cell-cell adherence than to formation of GJ channels. Furthermore, a crucial role of Cxs for the self-renewal and differentiation was shown in cultivated adult mesenchymal stem cells. This review aims to highlight aspects that link Cxs to the function and physiology of stem cell development.
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Affiliation(s)
- Anaclet Ngezahayo
- Dept. Cell Physiology and Biophysics, Institute of Cell Biology and Biophysics, Leibniz University Hannover, Hannover, Germany.,Center for Systems Neuroscience (ZSN), University of Veterinary Medicine Hannover, Hannover, Germany
| | - Frederike A Ruhe
- Dept. Cell Physiology and Biophysics, Institute of Cell Biology and Biophysics, Leibniz University Hannover, Hannover, Germany
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8
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Connexin 43 and Connexin 26 Involvement in the Ponatinib-Induced Cardiomyopathy: Sex-Related Differences in a Murine Model. Int J Mol Sci 2021; 22:ijms22115815. [PMID: 34071707 PMCID: PMC8199144 DOI: 10.3390/ijms22115815] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Revised: 05/24/2021] [Accepted: 05/25/2021] [Indexed: 12/15/2022] Open
Abstract
Cardiac connexins (Cxs) are proteins responsible for proper heart function. They form gap junctions that mediate electrical and chemical signalling throughout the cardiac system, and thus enable a synchronized contraction. Connexins can also individually participate in many signal transduction pathways, interacting with intracellular proteins at various cellular compartments. Altered connexin expression and localization have been described in diseased myocardium and the aim of this study is to assess the involvement of Cx43, Cx26, and some related molecules in ponatinib-induced cardiac toxicity. Ponatinib is a new multi-tyrosine kinase inhibitor that has been successfully used against human malignancies, but its cardiotoxicity remains worrisome. Therefore, understanding its signaling mechanism is important to adopt potential anti cardiac damage strategies. Our experiments were performed on hearts from male and female mice treated with ponatinib and with ponatinib plus siRNA-Notch1 by using immunofluorescence, Western blotting, and proteomic analyses. The altered cardiac function and the change in Cxs expression observed in mice after ponatinib treatment, were results dependent on the Notch1 pathway and sex. Females showed a lower susceptibility to ponatinib than males. The downmodulation of cardiac Cx43, Cx26 and miR-122, high pS368-Cx43 phosphorylation, cell viability and survival activation could represent some of the female adaptative/compensatory reactions to ponatinib cardiotoxicity.
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9
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Moscato S, Cabiati M, Bianchi F, Panetta D, Burchielli S, Massimetti G, Del Ry S, Mattii L. Heart and liver connexin expression related to the first stage of aging: A study on naturally aged animals. Acta Histochem 2020; 122:151651. [PMID: 33171391 DOI: 10.1016/j.acthis.2020.151651] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Revised: 10/09/2020] [Accepted: 10/27/2020] [Indexed: 12/26/2022]
Abstract
Connexins are membrane-spanning proteins that form membrane channels and hemichannels. They are involved in the cellular communication and in the maintenance of tissue homeostasis. Recent studies in humans and animals have demonstrated that the expression and distribution of Cx43, the most studied connexin, can change during aging. However, the research on the involvement of the other connexins in cardiac and hepatic aging is, at present, still very poor. Hence, the aim of this study is to evaluate the expression of Cx43 and Cx26 in the heart as well as Cx26 and Cx32 in the liver of a rat model that aged naturally, rather than prematurely because of genetic mutations or age-related diseases. The results obtained in the present study have demonstrated that these connexins decrease in rat cardiomyocytes and in rat hepatocytes as they age. This change was revealed only at protein level, as connexin-mRNAs remained unchanged during aging. Moreover, the aged rats showed an increase in body fat, whose subcutaneous layer tended to be higher. Finally, how these changes could represent signs of physiological adaptation in successful aging was discussed.
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Affiliation(s)
- Stefania Moscato
- Unit of Histology and Medical Embriology, Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy; University of Pisa, Interdepartmental Research Center Nutraceuticals and Food for Health, Pisa, Italy; Italian Institute of Technology, Smart Bio-Interfaces, Pontedera (Pisa), Italy
| | - Manuela Cabiati
- Laboratory of Biochemistry and Molecular Biology, Institute of Clinical Physiology, CNR, Pisa, Italy
| | - Francesco Bianchi
- Unit of Histology and Medical Embriology, Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - Daniele Panetta
- Laboratory of Biochemistry and Molecular Biology, Institute of Clinical Physiology, CNR, Pisa, Italy
| | | | - Gabriele Massimetti
- Psychiatric Clinic, Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - Silvia Del Ry
- Laboratory of Biochemistry and Molecular Biology, Institute of Clinical Physiology, CNR, Pisa, Italy; Institute of Life Sciences, ScuolaSuperioreSant'Anna, Pisa, Italy
| | - Letizia Mattii
- Unit of Histology and Medical Embriology, Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy; University of Pisa, Interdepartmental Research Center Nutraceuticals and Food for Health, Pisa, Italy.
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10
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Mattii L, Bianchi F, Falleni A, Frascarelli S, Masini M, Alì G, Chiellini G, Sabbatini ARM. Ultrastructural Localization of Histidine-rich Glycoprotein in Skeletal Muscle Fibers: Colocalization With AMP Deaminase. J Histochem Cytochem 2019; 68:139-148. [PMID: 31880188 DOI: 10.1369/0022155419897573] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Histidine-rich glycoprotein (HRG) is a plasma protein synthesized by the liver. We have given the first evidence of a tissue localization of HRG demonstrating its presence in skeletal muscle, associated with the zinc enzyme AMP deaminase (AMPD1). Moreover, we have shown that muscle cells do not synthesize HRG, but they can internalize it from plasma. We have recently demonstrated by confocal laser scanning microscopy that in human skeletal muscle, HRG is mainly localized in the myofibrils, preferentially at the I-band of the sarcomere, in the sarcoplasm, and in the nuclei. Using transmission electron microscopy and immunogold analysis, we carried out this study on human and rat normal skeletal muscles with the purpose to deepen the ultrastructural localization of HRG in skeletal muscle fibers. The immunogold analysis evidenced the presence of HRG in the sarcomeres, mainly in the I-band and to a less extent in the A-band, in the heterochromatin of nuclei, and in the sarcoplasmic reticulum. The colocalization of HRG and skeletal muscle AMPD1 was also analyzed. A colabeling of HRG and AMPD1 was evident at sarcomeric, sarcoplasmic reticulum, and nuclear levels. The significance of these interesting and new results is discussed in this article.
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Affiliation(s)
- Letizia Mattii
- Dipartimento di Medicina Clinica e Sperimentale, Università di Pisa, Pisa, Italy.,Nutrafood, Centro Interdipartimentale di Ricerca Nutraceutica e Alimentazione per la salute, Pisa, Italy
| | - Francesco Bianchi
- Dipartimento di Medicina Clinica e Sperimentale, Università di Pisa, Pisa, Italy
| | - Alessandra Falleni
- Dipartimento di Medicina Clinica e Sperimentale, Università di Pisa, Pisa, Italy
| | - Sabina Frascarelli
- Dipartimento di Patologia Chirurgica, Medica, Molecolare e dell'Area Critica, Università di Pisa, Pisa, Italy
| | - Matilde Masini
- Dipartimento di Ricerca Traslazionale e delle Nuove Tecnologie in Medicina e Chirurgia, Università di Pisa, Pisa, Italy
| | - Greta Alì
- U.O. Anatomia Patologica III, Azienda Ospedaliero Universitaria Pisana, Pisa, Italy
| | - Grazia Chiellini
- Dipartimento di Patologia Chirurgica, Medica, Molecolare e dell'Area Critica, Università di Pisa, Pisa, Italy
| | - Antonietta R M Sabbatini
- Dipartimento di Patologia Chirurgica, Medica, Molecolare e dell'Area Critica, Università di Pisa, Pisa, Italy
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11
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Wang H, Stahl F, Scheper T, Steffens M, Warnecke A, Zeilinger C. Microarray-based screening system identifies temperature-controlled activity of Connexin 26 that is distorted by mutations. Sci Rep 2019; 9:13543. [PMID: 31537823 PMCID: PMC6753059 DOI: 10.1038/s41598-019-49423-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Accepted: 08/24/2019] [Indexed: 11/09/2022] Open
Abstract
Here, we show that human Connexin 26 (hCx26 or Cx26WT) hemichannel opening rapidly enables the transport of small molecules when triggered by temperature and by compensation of the Ca2+ blockade with EDTA. Point mutations within Cx26 were analysed by a novel optical microarray-based Lucifer Yellow uptake assay or by two electrode voltage clamp (TEVC) on frog oocytes to monitor simultaneous activities of channel proteins. Point mutations L90P, F161S, R184P or K188N influenced the temperature-dependent activity drastically. Since several mutations blocked trafficking, the temperature-dependent activity of the recombinant synthesized and purified wild-type Cx26WT and Cx26K188N hemichannel was tested by liposome flux assay (LFA) and on a microarray-based Lucifer Yellow uptake assay under warm conditions (>30 °C). The data from TEVC measurements and dye flux experiments showed that the mutations gave no or only a weak activity at increased temperature (>30 °C). We conclude that the position K188 in the Cx26WT forms a temperature-sensitive salt bridge with E47 whereas the exchange to K188N destabilizes the network loop- gating filter, which was recently identified as a part of the flexible Ca2+ binding site. We assume that the temperature sensitivity of Cx26 is required to protect cells from uncontrolled release or uptake activities through Cx26 hemichannels.
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Affiliation(s)
- Hongling Wang
- Hannover Medical School, Department of Otorhinolaryngology, Head- and Neck-Surgery, Carl-Neuberg-Str. 1, 30625, Hannover, Germany.,Gottfried-Wilhelm-Leibniz University of Hannover, BMWZ (Zentrum für Biomolekulare Wirkstoffe), Schneiderberg 38, 30167, Hannover, Germany
| | - Frank Stahl
- Gottfried-Wilhelm-Leibniz University of Hannover, Institut für Technische Chemie/BMWZ (Zentrum für Biomolekulare Wirkstoffe), Callinstr. 5, 30167, Hannover, Germany.,Gottfried-Wilhelm-Leibniz University of Hannover, BMWZ (Zentrum für Biomolekulare Wirkstoffe), Schneiderberg 38, 30167, Hannover, Germany
| | - Thomas Scheper
- Gottfried-Wilhelm-Leibniz University of Hannover, Institut für Technische Chemie/BMWZ (Zentrum für Biomolekulare Wirkstoffe), Callinstr. 5, 30167, Hannover, Germany.,Gottfried-Wilhelm-Leibniz University of Hannover, BMWZ (Zentrum für Biomolekulare Wirkstoffe), Schneiderberg 38, 30167, Hannover, Germany
| | - Melanie Steffens
- Hannover Medical School, Department of Otorhinolaryngology, Head- and Neck-Surgery, Carl-Neuberg-Str. 1, 30625, Hannover, Germany
| | - Athanasia Warnecke
- Hannover Medical School, Department of Otorhinolaryngology, Head- and Neck-Surgery, Carl-Neuberg-Str. 1, 30625, Hannover, Germany.,Cluster of Excellence EXC1077 "Hearing4all", German Research Foundation (DFG; "Deutsche Forschungsgemeinschaft"), Hannover, Germany
| | - Carsten Zeilinger
- Gottfried-Wilhelm-Leibniz University of Hannover, BMWZ (Zentrum für Biomolekulare Wirkstoffe), Schneiderberg 38, 30167, Hannover, Germany.
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12
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Hausner EA, Elmore SA, Yang X. Overview of the Components of Cardiac Metabolism. Drug Metab Dispos 2019; 47:673-688. [PMID: 30967471 PMCID: PMC7333657 DOI: 10.1124/dmd.119.086611] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Accepted: 03/26/2019] [Indexed: 12/20/2022] Open
Abstract
Metabolism in organs other than the liver and kidneys may play a significant role in how a specific organ responds to chemicals. The heart has metabolic capability for energy production and homeostasis. This homeostatic machinery can also process xenobiotics. Cardiac metabolism includes the expression of numerous organic anion transporters, organic cation transporters, organic carnitine (zwitterion) transporters, and ATP-binding cassette transporters. Expression and distribution of the transporters within the heart may vary, depending on the patient’s age, disease, endocrine status, and various other factors. Several cytochrome P450 (P450) enzyme classes have been identified within the heart. The P450 hydroxylases and epoxygenases within the heart produce hydroxyeicosatetraneoic acids and epoxyeicosatrienoic acids, metabolites of arachidonic acid, which are critical in regulating homeostatic processes of the heart. The susceptibility of the cardiac P450 system to induction and inhibition from exogenous materials is an area of expanding knowledge, as are the metabolic processes of glucuronidation and sulfation in the heart. The susceptibility of various transcription factors and signaling pathways of the heart to disruption by xenobiotics is not fully characterized but is an area with implications for disruption of normal postnatal development, as well as modulation of adult cardiac health. There are knowledge gaps in the timelines of physiologic maturation and deterioration of cardiac metabolism. Cross-species characterization of cardiac-specific metabolism is needed for nonclinical work of optimum translational value to predict possible adverse effects, identify sensitive developmental windows for the design and conduct of informative nonclinical and clinical studies, and explore the possibilities of organ-specific therapeutics.
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Affiliation(s)
- Elizabeth A Hausner
- United States Food and Drug Administration, Center for Drug Evaluation and Research, Silver Spring, Maryland (E.A.H., X.Y.); and National Toxicology Program, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina (S.A.E.)
| | - Susan A Elmore
- United States Food and Drug Administration, Center for Drug Evaluation and Research, Silver Spring, Maryland (E.A.H., X.Y.); and National Toxicology Program, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina (S.A.E.)
| | - Xi Yang
- United States Food and Drug Administration, Center for Drug Evaluation and Research, Silver Spring, Maryland (E.A.H., X.Y.); and National Toxicology Program, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina (S.A.E.)
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