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Holmberg SR, Sakamoto Y, Kato A, Romero MF. The role of Na +-coupled bicarbonate transporters (NCBT) in health and disease. Pflugers Arch 2024; 476:479-503. [PMID: 38536494 PMCID: PMC11338471 DOI: 10.1007/s00424-024-02937-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2023] [Revised: 02/26/2024] [Accepted: 02/27/2024] [Indexed: 04/11/2024]
Abstract
Cellular and organism survival depends upon the regulation of pH, which is regulated by highly specialized cell membrane transporters, the solute carriers (SLC) (For a comprehensive list of the solute carrier family members, see: https://www.bioparadigms.org/slc/ ). The SLC4 family of bicarbonate (HCO3-) transporters consists of ten members, sorted by their coupling to either sodium (NBCe1, NBCe2, NBCn1, NBCn2, NDCBE), chloride (AE1, AE2, AE3), or borate (BTR1). The ionic coupling of SLC4A9 (AE4) remains controversial. These SLC4 bicarbonate transporters may be controlled by cellular ionic gradients, cellular membrane voltage, and signaling molecules to maintain critical cellular and systemic pH (acid-base) balance. There are profound consequences when blood pH deviates even a small amount outside the normal range (7.35-7.45). Chiefly, Na+-coupled bicarbonate transporters (NCBT) control intracellular pH in nearly every living cell, maintaining the biological pH required for life. Additionally, NCBTs have important roles to regulate cell volume and maintain salt balance as well as absorption and secretion of acid-base equivalents. Due to their varied tissue expression, NCBTs have roles in pathophysiology, which become apparent in physiologic responses when their expression is reduced or genetically deleted. Variations in physiological pH are seen in a wide variety of conditions, from canonically acid-base related conditions to pathologies not necessarily associated with acid-base dysfunction such as cancer, glaucoma, or various neurological diseases. The membranous location of the SLC4 transporters as well as recent advances in discovering their structural biology makes them accessible and attractive as a druggable target in a disease context. The role of sodium-coupled bicarbonate transporters in such a large array of conditions illustrates the potential of treating a wide range of disease states by modifying function of these transporters, whether that be through inhibition or enhancement.
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Affiliation(s)
- Shannon R Holmberg
- Physiology & Biomedical Engineering, Mayo Clinic College of Medicine & Science, 200 1st Street SW, Rochester, MN 55905, USA
- Biochemistry & Molecular Biology, Mayo Clinic College of Medicine & Science, 200 1st Street SW, Rochester, MN, USA
| | - Yohei Sakamoto
- School of Life Science and Technology, Tokyo Institute of Technology, Midori-Ku, Yokohama, 226-8501, Japan
| | - Akira Kato
- School of Life Science and Technology, Tokyo Institute of Technology, Midori-Ku, Yokohama, 226-8501, Japan
| | - Michael F Romero
- Physiology & Biomedical Engineering, Mayo Clinic College of Medicine & Science, 200 1st Street SW, Rochester, MN 55905, USA.
- Nephrology & Hypertension, Mayo Clinic College of Medicine & Science, 200 1st Street SW, Rochester, MN, USA.
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Liu Z, Wang Q, Zhai G, Ke S, Yu X, Guo J. SLC4A4 promotes prostate cancer progression in vivo and in vitro via AKT-mediated signalling pathway. Cancer Cell Int 2022; 22:127. [PMID: 35305629 PMCID: PMC8933877 DOI: 10.1186/s12935-022-02546-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Accepted: 03/10/2022] [Indexed: 01/23/2023] Open
Abstract
Abstract
Background
Prostate cancer (PCa) is the second leading cause of cancer-related male deaths worldwide. The purpose of this study was to investigate the effects of homo sapiens solute carrier family 4 member 4 (SLC4A4), which encodes the electrogenic Na+/HCO3− cotransporter isoform 1 (NBCe1), in the development and progression of PCa.
Methods
The expression levels of SLC4A4 in PCa and normal prostate tissues were evaluated by immunohistochemistry. The SLC4A4 knockdown cell model was structured by lentiviral infection, and the knockdown efficiency was validated by RT-qPCR and Western blotting. The effects of SLC4A4 knockdown on cell proliferation, apoptosis and cycle, migration, and invasion were detected by Celigo cell counting assay and CCK-8 assay, flow cytometry analysis, wound-healing, and Transwell assay, respectively. Tumor growth in nude mice was surveyed by in vivo imaging and Ki-67 staining. Furthermore, underlying mechanism of SLC4A4 silence induced inhibition of PCa progression was explored by human phospho-kinase array.
Results
Our results revealed that SLC4A4 expression was up-regulated in PCa tissues and human PCa cell lines. High expression of SLC4A4 in tumor specimens was significantly correlated with disease progression. SLC4A4 knockdown inhibited cell proliferation, migration and invasion, while facilitated apoptosis, which was also confirmed in vivo. Moreover, SLC4A4 promoted PCa progression through the AKT-mediated signalling pathway.
Conclusion
The results of this study indicated that SLC4A4 overexpression was closely associated with the progression of PCa; SLC4A4 knockdown suppressed PCa development in vitro and in vivo. SLC4A4 acts as a tumor promotor in PCa by regulating key components of the AKT pathway and may therefore act as a potential therapeutic target for PCa treatment.
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Zhao W, Zhang L, Ermilov LG, Colmenares Aguilar MG, Linden DR, Eisenman ST, Romero MF, Farrugia G, Sha L, Gibbons SJ. Bicarbonate ion transport by the electrogenic Na + /HCO 3- cotransporter, NBCe1, is required for normal electrical slow-wave activity in mouse small intestine. Neurogastroenterol Motil 2021; 33:e14149. [PMID: 33837991 PMCID: PMC8485339 DOI: 10.1111/nmo.14149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Revised: 02/26/2021] [Accepted: 03/21/2021] [Indexed: 02/08/2023]
Abstract
BACKGROUND Normal gastrointestinal motility depends on electrical slow-wave activity generated by interstitial cells of Cajal (ICC) in the tunica muscularis of the gastrointestinal tract. A requirement for HCO3- in extracellular solutions used to record slow waves indicates a role for HCO3- transport in ICC pacemaking. The Slc4a4 gene transcript encoding the electrogenic Na+ /HCO3- cotransporter, NBCe1, is enriched in mouse small intestinal myenteric region ICC (ICC-MY) that generate slow waves. This study aimed to determine how extracellular HCO3- concentrations affect electrical activity in mouse small intestine and to determine the contribution of NBCe1 activity to these effects. METHODS Immunohistochemistry and sharp electrode electrical recordings were used. KEY RESULTS The NBCe1 immunoreactivity was localized to ICC-MY of the tunica muscularis. In sharp electrode electrical recordings, removal of HCO3- from extracellular solutions caused significant, reversible, depolarization of the smooth muscle and a reduction in slow-wave amplitude and frequency. In 100 mM HCO3- , the muscle hyperpolarized and slow wave amplitude and frequency increased. The effects of replacing extracellular Na+ with Li+ , an ion that does not support NBCe1 activity, were similar to, but larger than, the effects of removing HCO3- . There were no additional changes to electrical activity when HCO3- was removed from Li+ containing solutions. The Na+ /HCO3- cotransport inhibitor, S-0859 (30µM) significantly reduced the effect of removing HCO3- on electrical activity. CONCLUSIONS & INFERENCES These studies demonstrate a major role for Na+ /HCO3- cotransport by NBCe1 in electrical activity of mouse small intestine and indicated that regulation of intracellular acid:base homeostasis contributes to generation of normal pacemaker activity in the gastrointestinal tract.
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Affiliation(s)
- Wenchang Zhao
- Enteric Neuroscience Program, Division of Gastroenterology and Hepatology, Rochester, Minnesota, USA.,Physiology and Biomedical Engineering, Rochester, Minnesota, USA.,Neuroendocrine Pharmacology, China Medical University, Shenyang, Liaoning Province, P. R. China
| | - Liwen Zhang
- Enteric Neuroscience Program, Division of Gastroenterology and Hepatology, Rochester, Minnesota, USA.,Physiology and Biomedical Engineering, Rochester, Minnesota, USA.,Neuroendocrine Pharmacology, China Medical University, Shenyang, Liaoning Province, P. R. China
| | - Leonid G. Ermilov
- Enteric Neuroscience Program, Division of Gastroenterology and Hepatology, Rochester, Minnesota, USA.,Physiology and Biomedical Engineering, Rochester, Minnesota, USA
| | - Maria Gabriela Colmenares Aguilar
- Enteric Neuroscience Program, Division of Gastroenterology and Hepatology, Rochester, Minnesota, USA.,Physiology and Biomedical Engineering, Rochester, Minnesota, USA
| | - David R. Linden
- Enteric Neuroscience Program, Division of Gastroenterology and Hepatology, Rochester, Minnesota, USA.,Physiology and Biomedical Engineering, Rochester, Minnesota, USA
| | - Seth T. Eisenman
- Enteric Neuroscience Program, Division of Gastroenterology and Hepatology, Rochester, Minnesota, USA.,Physiology and Biomedical Engineering, Rochester, Minnesota, USA
| | - Michael F. Romero
- Physiology and Biomedical Engineering, Rochester, Minnesota, USA.,Division of Nephrology and Hypertension, Mayo Clinic, Rochester, Minnesota, USA
| | - Gianrico Farrugia
- Enteric Neuroscience Program, Division of Gastroenterology and Hepatology, Rochester, Minnesota, USA.,Physiology and Biomedical Engineering, Rochester, Minnesota, USA
| | - Lei Sha
- Neuroendocrine Pharmacology, China Medical University, Shenyang, Liaoning Province, P. R. China.,Corresponding Authors: Simon J Gibbons, Ph.D., Enteric Neuroscience Program, Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, MN, 55905, USA. . Telephone: +1 507 284 9652, Lei Sha, M.D., China Medical University, 77 Pu He Road, Shenbei New District, Shenyang, Liaoning Province, P. R. China, 110122, , . Telephone: +86 18900911003
| | - Simon J. Gibbons
- Enteric Neuroscience Program, Division of Gastroenterology and Hepatology, Rochester, Minnesota, USA.,Physiology and Biomedical Engineering, Rochester, Minnesota, USA.,Corresponding Authors: Simon J Gibbons, Ph.D., Enteric Neuroscience Program, Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, MN, 55905, USA. . Telephone: +1 507 284 9652, Lei Sha, M.D., China Medical University, 77 Pu He Road, Shenbei New District, Shenyang, Liaoning Province, P. R. China, 110122, , . Telephone: +86 18900911003
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