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Retamal MA, Fernandez-Olivares A, Stehberg J. Over-activated hemichannels: A possible therapeutic target for human diseases. Biochim Biophys Acta Mol Basis Dis 2021; 1867:166232. [PMID: 34363932 DOI: 10.1016/j.bbadis.2021.166232] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 07/21/2021] [Accepted: 07/26/2021] [Indexed: 12/14/2022]
Abstract
In our body, all the cells are constantly sharing chemical and electrical information with other cells. This intercellular communication allows them to respond in a concerted way to changes in the extracellular milieu. Connexins are transmembrane proteins that have the particularity of forming two types of channels; hemichannels and gap junction channels. Under normal conditions, hemichannels allow the controlled release of signaling molecules to the extracellular milieu. However, under certain pathological conditions, over-activated hemichannels can induce and/or exacerbate symptoms. In the last decade, great efforts have been put into developing new tools that can modulate these over-activated hemichannels. Small molecules, antibodies and mimetic peptides have shown a potential for the treatment of human diseases. In this review, we summarize recent findings in the field of hemichannel modulation via specific tools, and how these tools could improve patient outcome in certain pathological conditions.
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Affiliation(s)
- Mauricio A Retamal
- Universidad del Desarrollo, Programa de Comunicación Celular en Cáncer, Santiago, Chile; Universidad del Desarrollo, Centro de Fisiología Celular e Integrativa, Santiago, Chile.
| | | | - Jimmy Stehberg
- Laboratorio de Neurobiología, Instituto de Ciencias Biomédicas, Facultad de medicina y Facultad de Ciencias de la Vida, Universidad Andres Bello, Santiago, Chile
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Natha CM, Vemulapalli V, Fiori MC, Chang CWT, Altenberg GA. Connexin hemichannel inhibitors with a focus on aminoglycosides. Biochim Biophys Acta Mol Basis Dis 2021; 1867:166115. [PMID: 33711451 DOI: 10.1016/j.bbadis.2021.166115] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Revised: 02/06/2021] [Accepted: 02/22/2021] [Indexed: 12/31/2022]
Abstract
Connexins are membrane proteins involved directly in cell-to-cell communication through the formation of gap-junctional channels. These channels result from the head-to-head docking of two hemichannels, one from each of two adjacent cells. Undocked hemichannels are also present at the plasma membrane where they mediate the efflux of molecules that participate in autocrine and paracrine signaling, but abnormal increase in hemichannel activity can lead to cell damage in disorders such as cardiac infarct, stroke, deafness, cataracts, and skin diseases. For this reason, connexin hemichannels have emerged as a valid therapeutic target. Know small molecule hemichannel inhibitors are not ideal leads for the development of better drugs for clinical use because they are not specific and/or have toxic effects. Newer inhibitors are more selective and include connexin mimetic peptides, anti-connexin antibodies and drugs that reduce connexin expression such as antisense oligonucleotides. Re-purposed drugs and their derivatives are also promising because of the significant experience with their clinical use. Among these, aminoglycoside antibiotics have been identified as inhibitors of connexin hemichannels that do not inhibit gap-junctional channels. In this review, we discuss connexin hemichannels and their inhibitors, with a focus on aminoglycoside antibiotics and derivatives of kanamycin A that inhibit connexin hemichannels, but do not have antibiotic effect.
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Affiliation(s)
- Cristina M Natha
- Department of Cell Physiology and Molecular Biophysics, and Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, TX, USA
| | - Varun Vemulapalli
- Department of Cell Physiology and Molecular Biophysics, and Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, TX, USA
| | - Mariana C Fiori
- Department of Cell Physiology and Molecular Biophysics, and Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, TX, USA
| | - Cheng-Wei T Chang
- Department of Chemistry and Biochemistry, Utah State University, Logan, UT, USA
| | - Guillermo A Altenberg
- Department of Cell Physiology and Molecular Biophysics, and Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, TX, USA.
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Subedi YP, Kjellgren A, Roberts P, Montgomery H, Thackeray N, Fiori MC, Altenberg GA, Chang CWT. Amphiphilic aminoglycosides with increased selectivity for inhibition of connexin 43 (Cx43) hemichannels. Eur J Med Chem 2020; 203:112602. [PMID: 32679454 DOI: 10.1016/j.ejmech.2020.112602] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2020] [Revised: 06/18/2020] [Accepted: 06/18/2020] [Indexed: 12/20/2022]
Abstract
Gap junction channels formed by the association of connexin hemichannels play a crucial role in intercellular communication. Connexin 43 (Cx43) is expressed in a variety of tissues and organs, including heart and brain, and abnormal sustained opening of undocked "free" hemichannels contributes to the cell damage in cardiac infarcts and stroke. Selective inhibitors of Cx43 hemichannels for clinical use are then desirable. Here, we synthesized and tested new aminoglycosides for their connexin inhibitory activity towards Cx26 and Cx43 hemichannels. The lead compounds displayed enhanced Cx43/Cx26 selectivity for hemichannel inhibition when compared to the parent kanamycin A and other commercially available aminoglycosides. These lead compounds are not cytotoxic to mammalian cells and show promise for the treatment of ischemic damage of the heart, brain, and kidneys. We identified a new compound as a promising lead based on its good selectivity for Cx43 hemichannels inhibition and the simplicity and affordability of its production.
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Affiliation(s)
- Yagya P Subedi
- Department of Chemistry and Biochemistry, Utah State University, 0300, Old Main Hill, Logan, UT, 84322-0300, USA
| | - Abbey Kjellgren
- Department of Cell Physiology and Molecular Biophysics, And Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, TX, 79430-6551, USA
| | - Paul Roberts
- Department of Chemistry and Biochemistry, Utah State University, 0300, Old Main Hill, Logan, UT, 84322-0300, USA
| | - Heath Montgomery
- Department of Chemistry and Biochemistry, Utah State University, 0300, Old Main Hill, Logan, UT, 84322-0300, USA
| | - Noah Thackeray
- Department of Chemistry and Biochemistry, Utah State University, 0300, Old Main Hill, Logan, UT, 84322-0300, USA
| | - Mariana C Fiori
- Department of Cell Physiology and Molecular Biophysics, And Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, TX, 79430-6551, USA
| | - Guillermo A Altenberg
- Department of Cell Physiology and Molecular Biophysics, And Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, TX, 79430-6551, USA
| | - Cheng-Wei T Chang
- Department of Chemistry and Biochemistry, Utah State University, 0300, Old Main Hill, Logan, UT, 84322-0300, USA.
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