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Mendoza-León MJ, Mangalam AK, Regaldiz A, González-Madrid E, Rangel-Ramírez MA, Álvarez-Mardonez O, Vallejos OP, Méndez C, Bueno SM, Melo-González F, Duarte Y, Opazo MC, Kalergis AM, Riedel CA. Gut microbiota short-chain fatty acids and their impact on the host thyroid function and diseases. Front Endocrinol (Lausanne) 2023; 14:1192216. [PMID: 37455925 PMCID: PMC10349397 DOI: 10.3389/fendo.2023.1192216] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Accepted: 05/23/2023] [Indexed: 07/18/2023] Open
Abstract
Thyroid disorders are clinically characterized by alterations of L-3,5,3',5'-tetraiodothyronine (T4), L-3,5,3'-triiodothyronine (T3), and/or thyroid-stimulating hormone (TSH) levels in the blood. The most frequent thyroid disorders are hypothyroidism, hyperthyroidism, and hypothyroxinemia. These conditions affect cell differentiation, function, and metabolism. It has been reported that 40% of the world's population suffers from some type of thyroid disorder and that several factors increase susceptibility to these diseases. Among them are iodine intake, environmental contamination, smoking, certain drugs, and genetic factors. Recently, the intestinal microbiota, composed of more than trillions of microbes, has emerged as a critical player in human health, and dysbiosis has been linked to thyroid diseases. The intestinal microbiota can affect host physiology by producing metabolites derived from dietary fiber, such as short-chain fatty acids (SCFAs). SCFAs have local actions in the intestine and can affect the central nervous system and immune system. Modulation of SCFAs-producing bacteria has also been connected to metabolic diseases, such as obesity and diabetes. In this review, we discuss how alterations in the production of SCFAs due to dysbiosis in patients could be related to thyroid disorders. The studies reviewed here may be of significant interest to endocrinology researchers and medical practitioners.
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Affiliation(s)
- María José Mendoza-León
- Departamento de Ciencias Biológicas, Facultad de Ciencias de la Vida, Universidad Andrés Bello, Santiago, Chile
- Millennium Institute on Immunology and Immunotherapy, Santiago, Chile
| | | | - Alejandro Regaldiz
- Departamento de Ciencias Biológicas, Facultad de Ciencias de la Vida, Universidad Andrés Bello, Santiago, Chile
- Millennium Institute on Immunology and Immunotherapy, Santiago, Chile
- Facultad de Medicina Veterinaria y Agronomía, Instituto de Ciencias Naturales, Universidad de las Américas, Santiago, Chile
| | - Enrique González-Madrid
- Departamento de Ciencias Biológicas, Facultad de Ciencias de la Vida, Universidad Andrés Bello, Santiago, Chile
- Millennium Institute on Immunology and Immunotherapy, Santiago, Chile
| | - Ma. Andreina Rangel-Ramírez
- Departamento de Ciencias Biológicas, Facultad de Ciencias de la Vida, Universidad Andrés Bello, Santiago, Chile
- Millennium Institute on Immunology and Immunotherapy, Santiago, Chile
| | - Oscar Álvarez-Mardonez
- Departamento de Ciencias Biológicas, Facultad de Ciencias de la Vida, Universidad Andrés Bello, Santiago, Chile
- Millennium Institute on Immunology and Immunotherapy, Santiago, Chile
| | - Omar P. Vallejos
- Millennium Institute on Immunology and Immunotherapy, Santiago, Chile
- Millennium Institute of Immunology and Immunotherapy, Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Constanza Méndez
- Millennium Institute on Immunology and Immunotherapy, Santiago, Chile
- Millennium Institute of Immunology and Immunotherapy, Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Susan M. Bueno
- Millennium Institute on Immunology and Immunotherapy, Santiago, Chile
- Millennium Institute of Immunology and Immunotherapy, Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Felipe Melo-González
- Departamento de Ciencias Biológicas, Facultad de Ciencias de la Vida, Universidad Andrés Bello, Santiago, Chile
- Millennium Institute on Immunology and Immunotherapy, Santiago, Chile
| | - Yorley Duarte
- Center for Bioinformatics and Integrative Biology, Facultad de Ciencias de la Vida, Universidad Andrés Bello, Santiago, Chile
| | - Ma. Cecilia Opazo
- Millennium Institute on Immunology and Immunotherapy, Santiago, Chile
- Facultad de Medicina Veterinaria y Agronomía, Instituto de Ciencias Naturales, Universidad de las Américas, Santiago, Chile
| | - Alexis M. Kalergis
- Millennium Institute on Immunology and Immunotherapy, Santiago, Chile
- Millennium Institute of Immunology and Immunotherapy, Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
- Departamento de Endocrinología, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Claudia A. Riedel
- Departamento de Ciencias Biológicas, Facultad de Ciencias de la Vida, Universidad Andrés Bello, Santiago, Chile
- Millennium Institute on Immunology and Immunotherapy, Santiago, Chile
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O'Riordan KJ, Collins MK, Moloney GM, Knox EG, Aburto MR, Fülling C, Morley SJ, Clarke G, Schellekens H, Cryan JF. Short chain fatty acids: Microbial metabolites for gut-brain axis signalling. Mol Cell Endocrinol 2022; 546:111572. [PMID: 35066114 DOI: 10.1016/j.mce.2022.111572] [Citation(s) in RCA: 119] [Impact Index Per Article: 59.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Revised: 01/07/2022] [Accepted: 01/11/2022] [Indexed: 02/08/2023]
Abstract
The role of the intestinal microbiota as a regulator of gut-brain axis signalling has risen to prominence in recent years. Understanding the relationship between the gut microbiota, the metabolites it produces, and the brain will be critical for the subsequent development of new therapeutic approaches, including the identification of novel psychobiotics. A key focus in this regard have been the short-chain fatty acids (SCFAs) produced by bacterial fermentation of dietary fibre, which include butyrate, acetate, and propionate. Ongoing research is focused on the entry of SCFAs into systemic circulation from the gut lumen, their migration to cerebral circulation and across the blood brain barrier, and their potential to exert acute and chronic effects on brain structure and function. This review aims to discuss our current mechanistic understanding of the direct and indirect influence that SCFAs have on brain function, behaviour and physiology, which will inform future microbiota-targeted interventions for brain disorders.
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Affiliation(s)
| | - Michael K Collins
- APC Microbiome Ireland, University College Cork, Ireland; Department of Anatomy & Neuroscience, University College Cork, Ireland
| | - Gerard M Moloney
- APC Microbiome Ireland, University College Cork, Ireland; Department of Anatomy & Neuroscience, University College Cork, Ireland
| | - Emily G Knox
- APC Microbiome Ireland, University College Cork, Ireland; School of Pharmacy, University College Cork, Ireland
| | - María R Aburto
- APC Microbiome Ireland, University College Cork, Ireland
| | | | - Shane J Morley
- APC Microbiome Ireland, University College Cork, Ireland
| | - Gerard Clarke
- APC Microbiome Ireland, University College Cork, Ireland; Department of Psychiatry and Neurobehavioural Science, University College Cork, Cork, Ireland
| | - Harriët Schellekens
- APC Microbiome Ireland, University College Cork, Ireland; Department of Anatomy & Neuroscience, University College Cork, Ireland
| | - John F Cryan
- APC Microbiome Ireland, University College Cork, Ireland; Department of Anatomy & Neuroscience, University College Cork, Ireland.
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3
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Giri D, Hawton K, Senniappan S. Congenital hyperinsulinism: recent updates on molecular mechanisms, diagnosis and management. J Pediatr Endocrinol Metab 2022; 35:279-296. [PMID: 34547194 DOI: 10.1515/jpem-2021-0369] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Accepted: 08/30/2021] [Indexed: 12/20/2022]
Abstract
Congenital hyperinsulinism (CHI) is a rare disease characterized by an unregulated insulin release, leading to hypoglycaemia. It is the most frequent cause of persistent and severe hypoglycaemia in the neonatal period and early childhood. Mutations in 16 different key genes (ABCC8, KCNJ11, GLUD1, GCK, HADH, SLC16A1, UCP2, HNF4A, HNF1A, HK1, KCNQ1, CACNA1D, FOXA2, EIF2S3, PGM1 and PMM2) that are involved in regulating the insulin secretion from pancreatic β-cells have been described to be responsible for the underlying molecular mechanisms of CHI. CHI can also be associated with specific syndromes and can be secondary to intrauterine growth restriction (IUGR), maternal diabetes, birth asphyxia, etc. It is important to diagnose and promptly initiate appropriate management as untreated hypoglycaemia can be associated with significant neurodisability. CHI can be histopathologically classified into diffuse, focal and atypical forms. Advances in molecular genetics, imaging techniques (18F-fluoro-l-dihydroxyphenylalanine positron emission tomography/computed tomography scanning), novel medical therapies and surgical advances (laparoscopic pancreatectomy) have changed the management and improved the outcome of patients with CHI. This review article provides an overview of the background, clinical presentation, diagnosis, molecular genetics and therapy for children with different forms of CHI.
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Affiliation(s)
- Dinesh Giri
- Bristol Royal Hospital for Children, University Hospitals Bristol and Weston NHS Foundation Trust, Bristol, UK.,University of Bristol, Bristol, UK
| | - Katherine Hawton
- Bristol Royal Hospital for Children, University Hospitals Bristol and Weston NHS Foundation Trust, Bristol, UK
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Vander Linden C, Corbet C, Bastien E, Martherus R, Guilbaud C, Petit L, Wauthier L, Loriot A, De Smet C, Feron O. Therapy-induced DNA methylation inactivates MCT1 and renders tumor cells vulnerable to MCT4 inhibition. Cell Rep 2021; 35:109202. [PMID: 34077729 DOI: 10.1016/j.celrep.2021.109202] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2020] [Revised: 03/21/2021] [Accepted: 05/11/2021] [Indexed: 12/13/2022] Open
Abstract
Metabolic plasticity in cancer cells makes use of metabolism-targeting agents very challenging. Drug-induced metabolic rewiring may, however, uncover vulnerabilities that can be exploited. We report that resistance to glycolysis inhibitor 3-bromopyruvate (3-BrPA) arises from DNA methylation in treated cancer cells and subsequent silencing of the monocarboxylate transporter MCT1. We observe that, unexpectedly, 3-BrPA-resistant cancer cells mostly rely on glycolysis to sustain their growth, with MCT4 as an essential player to support lactate flux. This shift makes cancer cells particularly suited to adapt to hypoxic conditions and resist OXPHOS inhibitors and anti-proliferative chemotherapy. In contrast, blockade of MCT4 activity in 3-BrPA-exposed cancer cells with diclofenac or genetic knockout, inhibits growth of derived spheroids and tumors in mice. This study supports a potential mode of collateral lethality according to which metabolic adaptation of tumor cells to a first-line therapy makes them more responsive to a second-line treatment.
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Affiliation(s)
- Catherine Vander Linden
- Pole of Pharmacology and Therapeutics (FATH), Institut de Recherche Expérimentale et Clinique (IREC), UCLouvain, 57 Avenue Hippocrate B1.57.04, 1200 Brussels, Belgium
| | - Cyril Corbet
- Pole of Pharmacology and Therapeutics (FATH), Institut de Recherche Expérimentale et Clinique (IREC), UCLouvain, 57 Avenue Hippocrate B1.57.04, 1200 Brussels, Belgium.
| | - Estelle Bastien
- Pole of Pharmacology and Therapeutics (FATH), Institut de Recherche Expérimentale et Clinique (IREC), UCLouvain, 57 Avenue Hippocrate B1.57.04, 1200 Brussels, Belgium
| | - Ruben Martherus
- Pole of Pharmacology and Therapeutics (FATH), Institut de Recherche Expérimentale et Clinique (IREC), UCLouvain, 57 Avenue Hippocrate B1.57.04, 1200 Brussels, Belgium
| | - Céline Guilbaud
- Pole of Pharmacology and Therapeutics (FATH), Institut de Recherche Expérimentale et Clinique (IREC), UCLouvain, 57 Avenue Hippocrate B1.57.04, 1200 Brussels, Belgium
| | - Laurenne Petit
- Pole of Pharmacology and Therapeutics (FATH), Institut de Recherche Expérimentale et Clinique (IREC), UCLouvain, 57 Avenue Hippocrate B1.57.04, 1200 Brussels, Belgium
| | - Loris Wauthier
- Pole of Pharmacology and Therapeutics (FATH), Institut de Recherche Expérimentale et Clinique (IREC), UCLouvain, 57 Avenue Hippocrate B1.57.04, 1200 Brussels, Belgium
| | - Axelle Loriot
- Group of Genetics and Epigenetics, de Duve Institute, UCLouvain, 75 Avenue Hippocrate B1.75.04, 1200 Brussels, Belgium
| | - Charles De Smet
- Group of Genetics and Epigenetics, de Duve Institute, UCLouvain, 75 Avenue Hippocrate B1.75.04, 1200 Brussels, Belgium
| | - Olivier Feron
- Pole of Pharmacology and Therapeutics (FATH), Institut de Recherche Expérimentale et Clinique (IREC), UCLouvain, 57 Avenue Hippocrate B1.57.04, 1200 Brussels, Belgium.
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Felmlee MA, Jones RS, Rodriguez-Cruz V, Follman KE, Morris ME. Monocarboxylate Transporters (SLC16): Function, Regulation, and Role in Health and Disease. Pharmacol Rev 2020; 72:466-485. [PMID: 32144120 DOI: 10.1124/pr.119.018762] [Citation(s) in RCA: 168] [Impact Index Per Article: 42.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The solute carrier family 16 (SLC16) is comprised of 14 members of the monocarboxylate transporter (MCT) family that play an essential role in the transport of important cell nutrients and for cellular metabolism and pH regulation. MCTs 1-4 have been extensively studied and are involved in the proton-dependent transport of L-lactate, pyruvate, short-chain fatty acids, and monocarboxylate drugs in a wide variety of tissues. MCTs 1 and 4 are overexpressed in a number of cancers, and current investigations have focused on transporter inhibition as a novel therapeutic strategy in cancers. MCT1 has also been used in strategies aimed at enhancing drug absorption due to its high expression in the intestine. Other MCT isoforms are less well characterized, but ongoing studies indicate that MCT6 transports xenobiotics such as bumetanide, nateglinide, and probenecid, whereas MCT7 has been characterized as a transporter of ketone bodies. MCT8 and MCT10 transport thyroid hormones, and recently, MCT9 has been characterized as a carnitine efflux transporter and MCT12 as a creatine transporter. Expressed at the blood brain barrier, MCT8 mutations have been associated with an X-linked intellectual disability, known as Allan-Herndon-Dudley syndrome. Many MCT isoforms are associated with hormone, lipid, and glucose homeostasis, and recent research has focused on their potential roles in disease, with MCTs representing promising novel therapeutic targets. This review will provide a summary of the current literature focusing on the characterization, function, and regulation of the MCT family isoforms and on their roles in drug disposition and in health and disease. SIGNIFICANCE STATEMENT: The 14-member solute carrier family 16 of monocarboxylate transporters (MCTs) plays a fundamental role in maintaining intracellular concentrations of a broad range of important endogenous molecules in health and disease. MCTs 1, 2, and 4 (L-lactate transporters) are overexpressed in cancers and represent a novel therapeutic target in cancer. Recent studies have highlighted the importance of MCTs in glucose, lipid, and hormone homeostasis, including MCT8 in thyroid hormone brain uptake, MCT12 in carnitine transport, and MCT11 in type 2 diabetes.
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Affiliation(s)
- Melanie A Felmlee
- Department of Pharmaceutics and Medicinal Chemistry, Thomas J. Long School of Pharmacy and Health Sciences, University of the Pacific, Stockton, California (M.A.F.); Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, University at Buffalo, State University of New York, Buffalo, New York (R.S.J., V.R.-C., M.E.M.); and Certara Strategic Consulting, Certara USA, Princeton, New Jersey (K.E.F.)
| | - Robert S Jones
- Department of Pharmaceutics and Medicinal Chemistry, Thomas J. Long School of Pharmacy and Health Sciences, University of the Pacific, Stockton, California (M.A.F.); Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, University at Buffalo, State University of New York, Buffalo, New York (R.S.J., V.R.-C., M.E.M.); and Certara Strategic Consulting, Certara USA, Princeton, New Jersey (K.E.F.)
| | - Vivian Rodriguez-Cruz
- Department of Pharmaceutics and Medicinal Chemistry, Thomas J. Long School of Pharmacy and Health Sciences, University of the Pacific, Stockton, California (M.A.F.); Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, University at Buffalo, State University of New York, Buffalo, New York (R.S.J., V.R.-C., M.E.M.); and Certara Strategic Consulting, Certara USA, Princeton, New Jersey (K.E.F.)
| | - Kristin E Follman
- Department of Pharmaceutics and Medicinal Chemistry, Thomas J. Long School of Pharmacy and Health Sciences, University of the Pacific, Stockton, California (M.A.F.); Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, University at Buffalo, State University of New York, Buffalo, New York (R.S.J., V.R.-C., M.E.M.); and Certara Strategic Consulting, Certara USA, Princeton, New Jersey (K.E.F.)
| | - Marilyn E Morris
- Department of Pharmaceutics and Medicinal Chemistry, Thomas J. Long School of Pharmacy and Health Sciences, University of the Pacific, Stockton, California (M.A.F.); Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, University at Buffalo, State University of New York, Buffalo, New York (R.S.J., V.R.-C., M.E.M.); and Certara Strategic Consulting, Certara USA, Princeton, New Jersey (K.E.F.)
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Bernardino RL, Carrageta DF, Sousa M, Alves MG, Oliveira PF. pH and male fertility: making sense on pH homeodynamics throughout the male reproductive tract. Cell Mol Life Sci 2019; 76:3783-3800. [PMID: 31165202 PMCID: PMC11105638 DOI: 10.1007/s00018-019-03170-w] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2018] [Revised: 04/24/2019] [Accepted: 05/29/2019] [Indexed: 02/07/2023]
Abstract
In the male reproductive tract, ionic equilibrium is essential to maintain normal spermatozoa production and, hence, the reproductive potential. Among the several ions, HCO3- and H+ have a central role, mainly due to their role on pH homeostasis. In the male reproductive tract, the major players in pH regulation and homeodynamics are carbonic anhydrases (CAs), HCO3- membrane transporters (solute carrier 4-SLC4 and solute carrier 26-SLC26 family transporters), Na+-H+ exchangers (NHEs), monocarboxylate transporters (MCTs) and voltage-gated proton channels (Hv1). CAs and these membrane transporters are widely distributed throughout the male reproductive tract, where they play essential roles in the ionic balance of tubular fluids. CAs are the enzymes responsible for the production of HCO3- which is then transported by membrane transporters to ensure the maturation, storage, and capacitation of the spermatozoa. The transport of H+ is carried out by NHEs, Hv1, and MCTs and is essential for the electrochemical balance and for the maintenance of the pH within the physiological limits along the male reproductive tract. Alterations in HCO3- production and transport of ions have been associated with some male reproductive dysfunctions. Herein, we present an up-to-date review on the distribution and role of the main intervenient on pH homeodynamics in the fluids throughout the male reproductive tract. In addition, we discuss their relevance for the establishment of the male reproductive potential.
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Affiliation(s)
- Raquel L Bernardino
- Laboratory of Cell Biology, Department of Microscopy, Institute of Biomedical Sciences Abel Salazar and Unit for Multidisciplinary Research in Biomedicine, University of Porto, Porto, Portugal
| | - David F Carrageta
- Laboratory of Cell Biology, Department of Microscopy, Institute of Biomedical Sciences Abel Salazar and Unit for Multidisciplinary Research in Biomedicine, University of Porto, Porto, Portugal
| | - Mário Sousa
- Laboratory of Cell Biology, Department of Microscopy, Institute of Biomedical Sciences Abel Salazar and Unit for Multidisciplinary Research in Biomedicine, University of Porto, Porto, Portugal
| | - Marco G Alves
- Institute of Biomedical Sciences Abel Salazar and Unit for Multidisciplinary Research in Biomedicine, University of Porto, Porto, Portugal
| | - Pedro F Oliveira
- Laboratory of Cell Biology, Department of Microscopy, Institute of Biomedical Sciences Abel Salazar and Unit for Multidisciplinary Research in Biomedicine, University of Porto, Porto, Portugal.
- i3S-Institute for Innovation and Health Research, University of Porto, Porto, Portugal.
- Department of Genetics, Faculty of Medicine, University of Porto, Porto, Portugal.
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Ion Transporters, Channelopathies, and Glucose Disorders. Int J Mol Sci 2019; 20:ijms20102590. [PMID: 31137773 PMCID: PMC6566632 DOI: 10.3390/ijms20102590] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Revised: 05/21/2019] [Accepted: 05/22/2019] [Indexed: 01/19/2023] Open
Abstract
Ion channels and transporters play essential roles in excitable cells including cardiac, skeletal and smooth muscle cells, neurons, and endocrine cells. In pancreatic beta-cells, for example, potassium KATP channels link the metabolic signals generated inside the cell to changes in the beta-cell membrane potential, and ultimately regulate insulin secretion. Mutations in the genes encoding some ion transporter and channel proteins lead to disorders of glucose homeostasis (hyperinsulinaemic hypoglycaemia and different forms of diabetes mellitus). Pancreatic KATP, Non-KATP, and some calcium channelopathies and MCT1 transporter defects can lead to various forms of hyperinsulinaemic hypoglycaemia (HH). Mutations in the genes encoding the pancreatic KATP channels can also lead to different types of diabetes (including neonatal diabetes mellitus (NDM) and Maturity Onset Diabetes of the Young, MODY), and defects in the solute carrier family 2 member 2 (SLC2A2) leads to diabetes mellitus as part of the Fanconi–Bickel syndrome. Variants or polymorphisms in some ion channel genes and transporters have been reported in association with type 2 diabetes mellitus.
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8
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Galcheva S, Demirbilek H, Al-Khawaga S, Hussain K. The Genetic and Molecular Mechanisms of Congenital Hyperinsulinism. Front Endocrinol (Lausanne) 2019; 10:111. [PMID: 30873120 PMCID: PMC6401612 DOI: 10.3389/fendo.2019.00111] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Accepted: 02/06/2019] [Indexed: 12/13/2022] Open
Abstract
Congenital hyperinsulinism (CHI) is a heterogenous and complex disorder in which the unregulated insulin secretion from pancreatic beta-cells leads to hyperinsulinaemic hypoglycaemia. The severity of hypoglycaemia varies depending on the underlying molecular mechanism and genetic defects. The genetic and molecular causes of CHI include defects in pivotal pathways regulating the secretion of insulin from the beta-cell. Broadly these genetic defects leading to unregulated insulin secretion can be grouped into four main categories. The first group consists of defects in the pancreatic KATP channel genes (ABCC8 and KCNJ11). The second and third categories of conditions are enzymatic defects (such as GDH, GCK, HADH) and defects in transcription factors (for example HNF1α, HNF4α) leading to changes in nutrient flux into metabolic pathways which converge on insulin secretion. Lastly, a large number of genetic syndromes are now linked to hyperinsulinaemic hypoglycaemia. As the molecular and genetic basis of CHI has expanded over the last few years, this review aims to provide an up-to-date knowledge on the genetic causes of CHI.
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Affiliation(s)
- Sonya Galcheva
- Department of Paediatrics, University Hospital St. Marina, Varna Medical University, Varna, Bulgaria
| | - Hüseyin Demirbilek
- Department of Paediatric Endocrinology, Hacettepe University Faculty of Medicine, Ankara, Turkey
| | - Sara Al-Khawaga
- Division of Endocrinology, Department of Paediatric Medicine, Sidra Medicine, Doha, Qatar
| | - Khalid Hussain
- Division of Endocrinology, Department of Paediatric Medicine, Sidra Medicine, Doha, Qatar
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Maacha S, Hong J, von Lersner A, Zijlstra A, Belkhiri A. AXL Mediates Esophageal Adenocarcinoma Cell Invasion through Regulation of Extracellular Acidification and Lysosome Trafficking. Neoplasia 2018; 20:1008-1022. [PMID: 30189359 PMCID: PMC6126204 DOI: 10.1016/j.neo.2018.08.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Revised: 08/06/2018] [Accepted: 08/14/2018] [Indexed: 12/14/2022]
Abstract
Esophageal adenocarcinoma (EAC) is a highly aggressive malignancy that is characterized by resistance to chemotherapy and a poor clinical outcome. The overexpression of the receptor tyrosine kinase AXL is frequently associated with unfavorable prognosis in EAC. Although it is well documented that AXL mediates cancer cell invasion as a downstream effector of epithelial-to-mesenchymal transition, the precise molecular mechanism underlying this process is not completely understood. Herein, we demonstrate for the first time that AXL mediates cell invasion through the regulation of lysosomes peripheral distribution and cathepsin B secretion in EAC cell lines. Furthermore, we show that AXL-dependent peripheral distribution of lysosomes and cell invasion are mediated by extracellular acidification, which is potentiated by AXL-induced secretion of lactate through AKT-NF-κB-dependent MCT-1 regulation. Our novel mechanistic findings support future clinical studies to evaluate the therapeutic potential of the AXL inhibitor R428 (BGB324) in highly invasive EAC.
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Affiliation(s)
- Selma Maacha
- Department of Surgery, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Jun Hong
- Department of Surgery, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Ariana von Lersner
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University, Nashville, TN 37240, USA
| | - Andries Zijlstra
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University, Nashville, TN 37240, USA
| | - Abbes Belkhiri
- Department of Surgery, Vanderbilt University Medical Center, Nashville, TN 37232, USA.
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Gutiérrez IL, González-Prieto M, García-Bueno B, Caso JR, Feinstein DL, Madrigal JLM. CCL2 Induces the Production of β2 Adrenergic Receptors and Modifies Astrocytic Responses to Noradrenaline. Mol Neurobiol 2018; 55:7872-7885. [PMID: 29478130 DOI: 10.1007/s12035-018-0960-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Accepted: 02/12/2018] [Indexed: 12/12/2022]
Abstract
The decline in brain noradrenaline levels is associated with the progression of certain neurodegenerative diseases. This seems to be due, at least in part, to the ability of noradrenaline to limit glial activation and to reduce the damage associated with it. Our previous studies of the mechanisms involved in this process indicate that noradrenaline induces the production of the chemokine CCL2 in astrocytes. While CCL2 can protect neurons against certain injuries, its overproduction has also proven to be harmful and to prevent noradrenaline neuroprotective effects. Therefore, in this study, we analyze if the modifications caused to astrocytes by an excessive production of CCL2 may alter their response to noradrenaline. Using primary cultures of rat cortical astrocytes, we observed that CCL2 enhances the production of beta 2 adrenergic receptors in these cells. While this potentiates noradrenaline signaling through cAMP, the activation of the transcription factor CREB is inhibited by CCL2. Furthermore, although CCL2 potentiates noradrenaline induction of glycogenolysis, this does not translate into an augmented release of lactate, one of the processes through which astrocytes help support neurons. Additionally, other neuroprotective actions of noradrenaline, such as the production of brain derived neurotrophic factor and the inhibition of the inducible nitric oxide synthase in astrocytes were modified by CCL2. These data suggest that some of the central nervous system alterations related to CCL2 could be due to its effects on adrenergic receptors and its interference with noradrenaline signaling.
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Affiliation(s)
- Irene L Gutiérrez
- Department of Pharmacology, School of Medicine, Universidad Complutense de Madrid (UCM), Av. Complutense s/n, 28040, Madrid, Spain
- Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), Instituto de Investigación Neuroquímica (IUINQ-UCM) and Instituto de Investigación Sanitaria Hospital 12 de Octubre (Imas12), Madrid, Spain
| | - Marta González-Prieto
- Department of Pharmacology, School of Medicine, Universidad Complutense de Madrid (UCM), Av. Complutense s/n, 28040, Madrid, Spain
- Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), Instituto de Investigación Neuroquímica (IUINQ-UCM) and Instituto de Investigación Sanitaria Hospital 12 de Octubre (Imas12), Madrid, Spain
| | - Borja García-Bueno
- Department of Pharmacology, School of Medicine, Universidad Complutense de Madrid (UCM), Av. Complutense s/n, 28040, Madrid, Spain
- Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), Instituto de Investigación Neuroquímica (IUINQ-UCM) and Instituto de Investigación Sanitaria Hospital 12 de Octubre (Imas12), Madrid, Spain
| | - Javier R Caso
- Department of Pharmacology, School of Medicine, Universidad Complutense de Madrid (UCM), Av. Complutense s/n, 28040, Madrid, Spain
- Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), Instituto de Investigación Neuroquímica (IUINQ-UCM) and Instituto de Investigación Sanitaria Hospital 12 de Octubre (Imas12), Madrid, Spain
| | - Douglas L Feinstein
- Department of Anesthesiology, University of Illinois at Chicago and Jesse Brown VA Medical Center, Chicago, IL, 60612, USA
| | - José L M Madrigal
- Department of Pharmacology, School of Medicine, Universidad Complutense de Madrid (UCM), Av. Complutense s/n, 28040, Madrid, Spain.
- Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), Instituto de Investigación Neuroquímica (IUINQ-UCM) and Instituto de Investigación Sanitaria Hospital 12 de Octubre (Imas12), Madrid, Spain.
- Dpto. Farmacología, Fac. Medicina, Avda. Complutense s/n, 28040, Madrid, Spain.
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11
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Sivaprakasam S, Bhutia YD, Yang S, Ganapathy V. Short-Chain Fatty Acid Transporters: Role in Colonic Homeostasis. Compr Physiol 2017; 8:299-314. [PMID: 29357130 PMCID: PMC6019286 DOI: 10.1002/cphy.c170014] [Citation(s) in RCA: 157] [Impact Index Per Article: 22.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Short-chain fatty acids (SCFA; acetate, propionate, and butyrate) are generated in colon by bacterial fermentation of dietary fiber. Though diffusion in protonated form is a significant route, carrier-mediated mechanisms constitute the major route for the entry of SCFA in their anionic form into colonic epithelium. Several transport systems operate in cellular uptake of SCFA. MCT1 (SLC16A1) and MCT4 (SLC16A3) are H+-coupled and mediate electroneutral transport of SCFA (H+: SCFA stoichiometry; 1:1). MCT1 is expressed both in the apical membrane and basolateral membrane of colonic epithelium whereas MCT4 specifically in the basolateral membrane. SMCT1 (SLC5A8) and SMCT2 (SLC5A12) are Na+-coupled; SMCT1-mediated transport is electrogenic (Na+: SCFA stoichiometry; 2:1) whereas SMCT2-mediated transport is electroneutral (Na+: SCFA stoichiometry; 1:1). SMCT1 and SMCT2 are expressed exclusively in the apical membrane. An anion-exchange mechanism also operates in the apical membrane in which SCFA entry in anionic form is coupled to bicarbonate efflux; the molecular identity of this exchanger however remains unknown. All these transporters are subject to regulation, notably by their substrates themselves; this process involves cell-surface receptors with SCFA as signaling molecules. There are significant alterations in the expression of these transporters in ulcerative colitis and colon cancer. The tumor-associated changes occur via transcriptional regulation by p53 and HIF1α and by promoter methylation. As SCFA are obligatory for optimal colonic health, the transporters responsible for the entry and transcellular transfer of these bacterial products in colonic epithelium are critical determinants of colonic function under physiological conditions and in disease states. © 2018 American Physiological Society. Compr Physiol 8:299-314, 2018.
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Affiliation(s)
- Sathish Sivaprakasam
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock, Texas, USA
| | - Yangzom D. Bhutia
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock, Texas, USA
| | - Shengping Yang
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock, Texas, USA
| | - Vadivel Ganapathy
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock, Texas, USA
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12
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Abstract
Highlights Fermentation of the dietary fiber by intestinal microflora results in production of butyrate.Butyrate possesses anticarcinogenic effect at the colonic level.Three transporters (MCT1, SMCT1 and BCRP) regulate the intracellular concentration of BT in colonic epithelial cells.Changes in the expression of these transporters occur in colorectal cancer. Abstract Colorectal cancer (CRC) is one of the most common solid tumors worldwide. Consumption of dietary fiber is associated with a low risk of developing CRC. The fermentation of the dietary fiber by intestinal microflora results in production of butyrate (BT). This short-chain fatty acid is an important metabolic substrate in normal colonic epithelial cells and has important homeostatic functions at the colonic level. Because the cellular effects of BT (e.g. inhibition of histone deacetylases) are dependent on its intracellular concentration, knowledge on the mechanisms involved in BT membrane transport and its regulation seems particularly relevant. In this review, we will present the carrier-mediated mechanisms involved in BT membrane transport at the colonic epithelial level and their regulation, with an emphasis on CRC. Several xenobiotics known to modulate the risk for developing CRC are able to interfere with BT transport at the intestinal level. Thus, interference with BT transport certainly contributes to the anticarcinogenic or procarcinogenic effect of these compounds and these compounds may interfere with the anticarcinogenic effect of BT. Finally, we suggest that differences in BT transport between normal colonocytes and tumoral cells contribute to the "BT paradox" (the apparent opposing effect of BT in CRC cells and normal colonocytes).
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13
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Saxena S, Shukla D, Bansal A. Expression of Monocarboxylate Transporter Isoforms in Rat Skeletal Muscle Under Hypoxic Preconditioning and Endurance Training. High Alt Med Biol 2015; 17:32-42. [PMID: 26716978 DOI: 10.1089/ham.2015.0048] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
Abstract
Previously, we have reported the regulation of monocarboxylate transporters (MCT)1 and MCT4 by physiological stimuli such as hypoxia and exercise. In the present study, we have evaluated the effect of hypoxic preconditioning and training on expression of different MCT isoforms in muscles. We found the increased mRNA expression of MCT1, MCT11, and MCT12 after hypoxic preconditioning with cobalt chloride and training. However, the expression of other MCT isoforms increased marginally or even reduced after hypoxic preconditioning. Only the protein expression of MCT1 increased after hypoxia preconditioning. MCT2 protein expression increased after training only and MCT4 protein expression decreased both in preconditioning and hypoxic training. Furthermore, we found decreased plasma lactate level during hypoxia preconditioning (0.74-fold), exercise (0.78-fold), and hypoxia preconditioning along with exercise (0.67-fold), which indicates increased lactate uptake by skeletal muscle. The protein-protein interactions with hypoxia inducible factor-1 and MCT isoforms were also evaluated, but no interaction was found. In conclusion, we say that almost all MCTs are expressed in red gastrocnemius muscle at the mRNA level and their expression is regulated differently under hypoxia preconditioning and exercise condition.
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Affiliation(s)
- Saurabh Saxena
- 1 Experimental Biology Division, Defence Institute of Physiology & Allied Sciences , Defence Research and Development Organization, Delhi, India
| | - Dhananjay Shukla
- 2 Department of Biotechnology, Guru Ghasidas University , Bilaspur, India
| | - Anju Bansal
- 1 Experimental Biology Division, Defence Institute of Physiology & Allied Sciences , Defence Research and Development Organization, Delhi, India
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14
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Adeva-Andany M, López-Ojén M, Funcasta-Calderón R, Ameneiros-Rodríguez E, Donapetry-García C, Vila-Altesor M, Rodríguez-Seijas J. Comprehensive review on lactate metabolism in human health. Mitochondrion 2014; 17:76-100. [PMID: 24929216 DOI: 10.1016/j.mito.2014.05.007] [Citation(s) in RCA: 351] [Impact Index Per Article: 35.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2013] [Revised: 03/19/2014] [Accepted: 05/05/2014] [Indexed: 02/07/2023]
Abstract
Metabolic pathways involved in lactate metabolism are important to understand the physiological response to exercise and the pathogenesis of prevalent diseases such as diabetes and cancer. Monocarboxylate transporters are being investigated as potential targets for diagnosis and therapy of these and other disorders. Glucose and alanine produce pyruvate which is reduced to lactate by lactate dehydrogenase in the cytoplasm without oxygen consumption. Lactate removal takes place via its oxidation to pyruvate by lactate dehydrogenase. Pyruvate may be either oxidized to carbon dioxide producing energy or transformed into glucose. Pyruvate oxidation requires oxygen supply and the cooperation of pyruvate dehydrogenase, the tricarboxylic acid cycle, and the mitochondrial respiratory chain. Enzymes of the gluconeogenesis pathway sequentially convert pyruvate into glucose. Congenital or acquired deficiency on gluconeogenesis or pyruvate oxidation, including tissue hypoxia, may induce lactate accumulation. Both obese individuals and patients with diabetes show elevated plasma lactate concentration compared to healthy subjects, but there is no conclusive evidence of hyperlactatemia causing insulin resistance. Available evidence suggests an association between defective mitochondrial oxidative capacity in the pancreatic β-cells and diminished insulin secretion that may trigger the development of diabetes in patients already affected with insulin resistance. Several mutations in the mitochondrial DNA are associated with diabetes mellitus, although the pathogenesis remains unsettled. Mitochondrial DNA mutations have been detected in a number of human cancers. d-lactate is a lactate enantiomer normally formed during glycolysis. Excess d-lactate is generated in diabetes, particularly during diabetic ketoacidosis. d-lactic acidosis is typically associated with small bowel resection.
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Affiliation(s)
- M Adeva-Andany
- Nephrology Division, Hospital General Juan Cardona, Ave. Pardo Bazán, s/n, 15406 Ferrol, La Coruña, Spain.
| | - M López-Ojén
- Internal Medicine Division, Policlínica Assistens, c/Federico García, 4-planta baja, 15009 La Coruña, Spain
| | - R Funcasta-Calderón
- Nephrology Division, Hospital General Juan Cardona, Ave. Pardo Bazán, s/n, 15406 Ferrol, La Coruña, Spain
| | - E Ameneiros-Rodríguez
- Nephrology Division, Hospital General Juan Cardona, Ave. Pardo Bazán, s/n, 15406 Ferrol, La Coruña, Spain
| | - C Donapetry-García
- Nephrology Division, Hospital General Juan Cardona, Ave. Pardo Bazán, s/n, 15406 Ferrol, La Coruña, Spain
| | - M Vila-Altesor
- Nephrology Division, Hospital General Juan Cardona, Ave. Pardo Bazán, s/n, 15406 Ferrol, La Coruña, Spain
| | - J Rodríguez-Seijas
- Nephrology Division, Hospital General Juan Cardona, Ave. Pardo Bazán, s/n, 15406 Ferrol, La Coruña, Spain
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15
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Narumi K, Kobayashi M, Otake S, Furugen A, Takahashi N, Ogura J, Itagaki S, Hirano T, Yamaguchi H, Iseki K. Regulation of human monocarboxylate transporter 4 in skeletal muscle cells: The role of protein kinase C (PKC). Int J Pharm 2012; 428:25-32. [DOI: 10.1016/j.ijpharm.2012.02.021] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2011] [Revised: 01/30/2012] [Accepted: 02/10/2012] [Indexed: 11/16/2022]
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16
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König B, Fischer S, Schlotte S, Wen G, Eder K, Stangl GI. Monocarboxylate transporter 1 and CD147 are up-regulated by natural and synthetic peroxisome proliferator-activated receptor alpha agonists in livers of rodents and pigs. Mol Nutr Food Res 2011; 54:1248-56. [PMID: 20306479 DOI: 10.1002/mnfr.200900432] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Monocarboxylate transporter (MCT)-1 mediates the transport of ketone bodies and other monocarboxylic acids across the plasma membrane. MCT1 is up-regulated by peroxisome proliferator-activated receptor (PPAR)-alpha, a transcription factor that mediates the adaptive response to fasting by up-regulation of genes involved in fatty acid oxidation and ketogenesis. Here, we show for the first time that MCT1 is up-regulated by dietary natural PPAR-alpha agonists. Both, an oxidized fat and conjugated linoleic acids increased MCT1 mRNA concentration in the liver of rats. Also, in the liver of pigs as non-proliferating species MCT1 was up-regulated upon PPAR-alpha activation by clofibrate, oxidized fat and fasting. Concomitant with up-regulation of MCT1, mRNA level of CD147 was increased in livers of rats and pigs. CD147 is a plasma membrane glycoprotein that is required for translocation and transport activity of MCT1. CD147 mRNA increase upon PPAR-alpha activation could not be observed in mice lacking PPAR-alpha, which also fail in up-regulation of MCT1 indicating a co-regulation of MCT1 and CD147. Analysis of the 5'-flanking region of mouse MCT1 gene by reporter gene assay revealed that promoter activity of mouse MCT1 was not induced by PPAR-alpha, indicating that the 5'-flanking region is not involved in MCT1 regulation by PPAR-alpha.
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Affiliation(s)
- Bettina König
- Institute of Agricultural and Nutritional Sciences, Martin-Luther-University Halle-Wittenberg, Halle (Saale), Germany.
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17
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Saksena S, Theegala S, Bansal N, Gill RK, Tyagi S, Alrefai WA, Ramaswamy K, Dudeja PK. Mechanisms underlying modulation of monocarboxylate transporter 1 (MCT1) by somatostatin in human intestinal epithelial cells. Am J Physiol Gastrointest Liver Physiol 2009; 297:G878-85. [PMID: 20501436 PMCID: PMC2777453 DOI: 10.1152/ajpgi.00283.2009] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Somatostatin (SST), an important neuropeptide of the gastrointestinal tract has been shown to stimulate sodium chloride absorption and inhibit chloride secretion in the intestine. However, the effects of SST on luminal butyrate absorption in the human intestine have not been investigated. Earlier studies from our group and others have shown that monocarboxylate transporter (MCT1) plays an important role in the transport of butyrate in the human intestine. The present studies were undertaken to examine the effects of SST on butyrate uptake utilizing postconfluent human intestinal epithelial Caco2 cells. Apical SST treatment of Caco-2 cells for 30-60 min significantly increased butyrate uptake in a dose-dependent manner with maximal increase at 50 nM ( approximately 60%, P < 0.05). SST receptor 2 agonist, seglitide, mimicked the effects of SST on butyrate uptake. SST-mediated stimulation of butyrate uptake involved the p38 MAP kinase-dependent pathway. Kinetic studies demonstrated that SST increased the maximal velocity (V(max)) of the transporter by approximately twofold without any change in apparent Michaelis-Menten constant (K(m)). The higher butyrate uptake in response to SST was associated with an increase in the apical membrane levels of MCT1 protein parallel to a decrease in the intracellular MCT1 pool. MCT1 has been shown to interact specifically with CD147 glycoprotein/chaperone to facilitate proper expression and function of MCT1 at the cell surface. SST significantly enhanced the membrane levels of CD147 as well as its association with MCT1. This association was completely abolished by the specific p38 MAP kinase inhibitor, SB203580. Our findings demonstrate that increased MCT1 association with CD147 at the apical membrane in response to SST is p38 MAP kinase dependent and underlies the stimulatory effects of SST on butyrate uptake.
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Affiliation(s)
- Seema Saksena
- Section of Digestive Diseases and Nutrition, Department of Medicine, University of Illinois at Chicago and Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois 60612, USA.
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18
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Saksena S, Dwivedi A, Gill RK, Singla A, Alrefai WA, Malakooti J, Ramaswamy K, Dudeja PK. PKC-dependent stimulation of the human MCT1 promoter involves transcription factor AP2. Am J Physiol Gastrointest Liver Physiol 2009; 296:G275-83. [PMID: 19033536 PMCID: PMC2643915 DOI: 10.1152/ajpgi.90503.2008] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Monocarboxylate transporter (MCT1) plays an important role in the absorption of short-chain fatty acids (SCFA) such as butyrate in the human colon. Previous studies from our laboratory have demonstrated that phorbol ester, PMA (1 microM, 24 h), upregulates butyrate transport and MCT1 protein expression in human intestinal Caco-2 cells. However, the molecular mechanisms involved in the transcriptional regulation of MCT1 gene expression by PMA in the intestine are not known. In the present study, we showed that PMA (0.1 microM, 24 h) increased the MCT1 promoter activity (-871/+91) by approximately fourfold. A corresponding increase in MCT1 mRNA abundance in response to PMA was also observed. PMA-induced stimulation of MCT1 promoter activity was observed as early as 1 h and persisted until 24 h, suggesting that the effects of PMA are attributable to initial PKC activation. Kinase inhibitor and phosphorylation studies indicated that these effects may be mediated through activation of the atypical PKC-zeta isoform. 5'-deletion studies demonstrated that the MCT1 core promoter region (-229/+91) is the PMA-responsive region. Site-directed mutagenesis studies showed the predominant involvement of potential activator protein 2 (AP2) binding site in the activation of MCT1 promoter activity by PMA. In addition, overexpression of AP2 in Caco-2 cells significantly increased MCT1 promoter activity in a dose-dependent manner. These findings showing the regulation of MCT1 promoter by PKC and AP2 are of significant importance for an understanding of the molecular regulation of SCFA absorption in the human intestine.
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Affiliation(s)
- Seema Saksena
- Department of Medicine, University of Illinois at Chicago, Chicago, IL 60612, USA.
| | - Alka Dwivedi
- Section of Digestive Diseases and Nutrition, Department of Medicine, University of Illinois at Chicago and Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois
| | - Ravinder K. Gill
- Section of Digestive Diseases and Nutrition, Department of Medicine, University of Illinois at Chicago and Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois
| | - Amika Singla
- Section of Digestive Diseases and Nutrition, Department of Medicine, University of Illinois at Chicago and Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois
| | - Waddah A. Alrefai
- Section of Digestive Diseases and Nutrition, Department of Medicine, University of Illinois at Chicago and Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois
| | - Jaleh Malakooti
- Section of Digestive Diseases and Nutrition, Department of Medicine, University of Illinois at Chicago and Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois
| | - Krishnamurthy Ramaswamy
- Section of Digestive Diseases and Nutrition, Department of Medicine, University of Illinois at Chicago and Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois
| | - Pradeep K. Dudeja
- Section of Digestive Diseases and Nutrition, Department of Medicine, University of Illinois at Chicago and Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois
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19
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Lean CB, Lee EJD. Genetic Variations in the MCT1 (SLC16A1) Gene in the Chinese Population of Singapore. Drug Metab Pharmacokinet 2009; 24:469-74. [DOI: 10.2133/dmpk.24.469] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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20
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Borthakur A, Saksena S, Gill RK, Alrefai WA, Ramaswamy K, Dudeja PK. Regulation of monocarboxylate transporter 1 (MCT1) promoter by butyrate in human intestinal epithelial cells: involvement of NF-kappaB pathway. J Cell Biochem 2008; 103:1452-63. [PMID: 17786924 PMCID: PMC2673490 DOI: 10.1002/jcb.21532] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Butyrate, a short chain fatty acid (SCFA) produced by bacterial fermentation of undigested carbohydrates in the colon, constitutes the major fuel for colonocytes. We have earlier shown the role of apically localized monocarboxylate transporter isoform 1 (MCT1) in transport of butyrate into human colonic Caco-2 cells. In an effort to study the regulation of MCT1 gene, we and others have cloned the promoter region of the MCT1 gene and identified cis elements for key transcription factors. A previous study has shown up-regulation of MCT1 expression, and activity by butyrate in AA/C1 human colonic epithelial cells, however, the detailed mechanisms of this up-regulation are not known. In this study, we demonstrate that butyrate, a substrate for MCT1, stimulates MCT1 promoter activity in Caco-2 cells. This effect was dose dependent and specific to butyrate as other predominant SCFAs, acetate, and propionate, were ineffective. Utilizing progressive deletion constructs of the MCT1 promoter, we showed that the putative butyrate responsive elements are in the -229/+91 region of the promoter. Butyrate stimulation of the MCT1 promoter was found to be independent of PKC, PKA, and tyrosine kinases. However, specific inhibitors of the NF-kappaB pathway, lactacystein (LC), and caffeic acid phenyl ester (CAPE) significantly reduced the MCT1 promoter stimulation by butyrate. Also, butyrate directly stimulated NF-kappaB-dependent luciferase reporter activity. Histone deacetylase (HDAC) inhibitor trichostatin A (TSA) also stimulated MCT1 promoter activity, however, unlike butyrate, this stimulation was unaltered by the NF-kappaB inhibitors. Further, the combined effect of butyrate, and TSA on MCT1 promoter activity was additive, indicating that their mechanisms of action were independent. Our results demonstrate the involvement of NF-kappaB pathway in the regulation of MCT1 promoter activity by butyrate.
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Affiliation(s)
| | | | | | | | | | - Pradeep K. Dudeja
- Correspondence to: Pradeep K. Dudeja, PhD, Professor of Physiology in Medicine, University of Illinois at Chicago, Medical Research Service [600/151], Jesse Brown VA Medical Center, 820 South Damen Avenue Chicago, IL 60612. E-mail:
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21
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Evolution and functional divergence of monocarboxylate transporter genes in vertebrates. Gene 2008; 423:14-22. [PMID: 18674605 DOI: 10.1016/j.gene.2008.07.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2008] [Revised: 06/28/2008] [Accepted: 07/03/2008] [Indexed: 11/22/2022]
Abstract
Monocarboxylate transporters (MCTs) form a gene family with an ancient past. The identification of MCTs (MCHs) from bacteria, protozoa, fungi, invertebrates, as well as vertebrates, but not from plants and virus, allowed illuminating the phylogenetic and evolutionary history of this gene family. The significant expansion of vertebrate MCT genes should have primarily occurred after the divergence of vertebrates and invertebrates, but before the divergence time between ray-finned fish and mammals. The divergence of insect MCTs should have at least occurred in the common ancestor of fruit fly, beetle, and honeybee. Fungi monocarboxylate transporter homologues (MCHs) might evolve independently from an ancient ancestor. The results of functional divergence analysis provided statistical evidences for shifted evolutionary rate and/or changes of amino acid property after gene duplication. The sliding window analysis of the d(N)/d(S) ratio values showed that strong functional constraints must impose on the N- and C-terminal domains of vertebrate MCTs. These corresponding regions may play crucial roles for functionality of MCT proteins.
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22
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Morris ME, Felmlee MA. Overview of the proton-coupled MCT (SLC16A) family of transporters: characterization, function and role in the transport of the drug of abuse gamma-hydroxybutyric acid. AAPS JOURNAL 2008; 10:311-21. [PMID: 18523892 DOI: 10.1208/s12248-008-9035-6] [Citation(s) in RCA: 149] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Received: 03/04/2008] [Accepted: 04/01/2008] [Indexed: 11/30/2022]
Abstract
The transport of monocarboxylates, such as lactate and pyruvate, is mediated by the SLC16A family of proton-linked membrane transport proteins known as monocarboxylate transporters (MCTs). Fourteen MCT-related genes have been identified in mammals and of these seven MCTs have been functionally characterized. Despite their sequence homology, only MCT1-4 have been demonstrated to be proton-dependent transporters of monocarboxylic acids. MCT6, MCT8 and MCT10 have been demonstrated to transport diuretics, thyroid hormones and aromatic amino acids, respectively. MCT1-4 vary in their regulation, tissue distribution and substrate/inhibitor specificity with MCT1 being the most extensively characterized isoform. Emerging evidence suggests that in addition to endogenous substrates, MCTs are involved in the transport of pharmaceutical agents, including gamma-hydroxybuytrate (GHB), 3-hydroxy-3-methyl-glutaryl-coenzyme A reductase inhibitors (statins), salicylic acid, and bumetanide. MCTs are expressed in a wide range of tissues including the liver, intestine, kidney and brain, and as such they have the potential to impact a number of processes contributing to the disposition of xenobiotic substrates. GHB has been extensively studied as a pharmaceutical substrate of MCTs; the renal clearance of GHB is dose-dependent with saturation of MCT-mediated reabsorption at high doses. Concomitant administration of GHB and L: -lactate to rats results in an approximately two-fold increase in GHB renal clearance suggesting that inhibition of MCT1-mediated reabsorption of GHB may be an effective strategy for increasing renal and total GHB elimination in overdose situations. Further studies are required to more clearly define the role of MCTs on drug disposition and the potential for MCT-mediated detoxification strategies in GHB overdose.
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Affiliation(s)
- Marilyn E Morris
- Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, University at Buffalo, State University of New York, Amherst, New York 14260, USA.
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23
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Thibault R, De Coppet P, Daly K, Bourreille A, Cuff M, Bonnet C, Mosnier JF, Galmiche JP, Shirazi-Beechey S, Segain JP. Down-regulation of the monocarboxylate transporter 1 is involved in butyrate deficiency during intestinal inflammation. Gastroenterology 2007; 133:1916-27. [PMID: 18054563 DOI: 10.1053/j.gastro.2007.08.041] [Citation(s) in RCA: 150] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/20/2006] [Accepted: 08/09/2007] [Indexed: 01/12/2023]
Abstract
BACKGROUND & AIMS Butyrate oxidation is impaired in intestinal mucosa of patients with inflammatory bowel diseases (IBD). Butyrate uptake by colonocytes involves the monocarboxylate transporter (MCT) 1. We aimed to investigate the role of MCT1 in butyrate oxidation deficiency during colonic inflammation. METHODS Colonic tissues were collected from patients with IBD or healthy controls and from rats with dextran sulfate sodium (DSS)-induced colitis. The intestinal epithelial cell line HT-29 was treated with interferon-gamma (IFN-gamma) and tumor necrosis factor-alpha (TNF-alpha). MCT1 expression was analyzed by real-time reverse-transcription polymerase chain reaction, Western blot, and immunofluorescence. Butyrate uptake and oxidation in HT-29 cells was assessed using [(14)C]-butyrate. The mechanism of MCT1 gene regulation was analyzed by nuclear run-on and reporter gene assays. RESULTS MCT1 messenger RNA (mRNA) and protein levels were markedly decreased in inflamed colonic mucosa of IBD patients and rats. In HT-29 cells, down-regulation of MCT1 mRNA and protein abundance by IFN-gamma and TNF-alpha correlated with a decrease in butyrate uptake and subsequent oxidation. IFN-gamma and TNF-alpha did not affect MCT1 mRNA stability but rather down-regulated gene transcription. We demonstrate that the cytokine response element is located in the proximal -111/+213 core region of the MCT1 promoter. CONCLUSIONS The data suggest that butyrate oxidation deficiency in intestinal inflammation is a consequence of reduction in MCT1-mediated butyrate uptake. This reinforces the proposition that butyrate oxidation deficiency in IBD is not a primary defect.
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Affiliation(s)
- Ronan Thibault
- UMR 1280 Physiologie des Adaptations Nutritionnelles, INRA, Université de Nantes, Nantes, France
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Zhang SXL, Searcy TR, Wu Y, Gozal D, Wang Y. Alternative promoter usage and alternative splicing contribute to mRNA heterogeneity of mouse monocarboxylate transporter 2. Physiol Genomics 2007; 32:95-104. [PMID: 17911380 DOI: 10.1152/physiolgenomics.00192.2007] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Expression patterns of monocarboxylate transporter 2 (MCT2) display mRNA diversity in a tissue-specific fashion. We cloned and characterized multiple mct2 5'-cDNA ends from the mouse and determined the structural organization of the mct2 gene. We found that transcription of this gene was initiated from five independent genomic regions that spanned >80 kb on chromosome 10, resulting in five unique exon 1 variants (exons 1a, 1b, 1c, 1d, and 1e) that were then spliced to the common exon 2. Alternative splicing of four internal exons (exons AS1, AS2, AS3, and exon 3) greatly increased the complexity of mRNA diversity. While exon 1c was relatively commonly used for transcription initiation in various tissues, other exon 1 variants were used in a tissue-specific fashion, especially exons 1b and 1d that were used exclusively for testis-specific expression. Sequence analysis of 5'-flanking regions upstream of exons 1a, 1b, and 1c revealed the presence of numerous potential binding sites for ubiquitous transcription factors in all three regions and for transcription factors implicated in testis-specific or hypoxia-induced gene expression in the 1b region. Transient transfection assays demonstrated that each of the three regions contained a functional promoter and that the in vitro, cell type-specific activities of these promoters were consistent with the tissue-specific expression pattern of the mct2 gene in vivo. These results indicate that tissue-specific expression of the mct2 gene is controlled by multiple alternative promoters and that both alternative promoter usage and alternative splicing contribute to the remarkable mRNA diversity of the gene.
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Affiliation(s)
- Shelley X L Zhang
- Kosair Children's Hospital Research Institute, Department of Pediatrics, University of Louisville, Louisville, Kentucky 40202, USA
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25
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Otonkoski T, Jiao H, Kaminen-Ahola N, Tapia-Paez I, Ullah MS, Parton LE, Schuit F, Quintens R, Sipilä I, Mayatepek E, Meissner T, Halestrap AP, Rutter GA, Kere J. Physical exercise-induced hypoglycemia caused by failed silencing of monocarboxylate transporter 1 in pancreatic beta cells. Am J Hum Genet 2007; 81:467-74. [PMID: 17701893 PMCID: PMC1950828 DOI: 10.1086/520960] [Citation(s) in RCA: 150] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2007] [Accepted: 05/21/2007] [Indexed: 01/03/2023] Open
Abstract
Exercise-induced hyperinsulinism (EIHI) is a dominantly inherited hypoglycemic disorder characterized by inappropriate insulin secretion during anaerobic exercise or on pyruvate load. We aimed to identify the molecular basis of this novel disorder of beta -cell regulation. EIHI mapped to chromosome 1 (LOD score 3.6) in a genome scan performed for two families with 10 EIHI-affected patients. Mutational analysis of the promoter of the SLC16A1 gene, which encodes monocarboxylate transporter 1 (MCT1), located under the linkage peak, revealed changes in all 13 identified patients with EIHI. Patient fibroblasts displayed abnormally high SLC16A1 transcript levels, although monocarboxylate transport activities were not changed in these cells, reflecting additional posttranscriptional control of MCT1 levels in extrapancreatic tissues. By contrast, when examined in beta cells, either of two SLC16A1 mutations identified in separate pedigrees resulted in increased protein binding to the corresponding promoter elements and marked (3- or 10-fold) transcriptional stimulation of SLC16A1 promoter-reporter constructs. These studies show that promoter-activating mutations in EIHI induce SLC16A1 expression in beta cells, where this gene is not usually transcribed, permitting pyruvate uptake and pyruvate-stimulated insulin release despite ensuing hypoglycemia. These findings describe a novel disease mechanism based on the failure of cell-specific transcriptional silencing of a gene that is highly expressed in other tissues.
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Affiliation(s)
- Timo Otonkoski
- Hospital for Children and Adolescents and Biomedicum Helsinki, University of Helsinki, Helsinki, Finland.
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26
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Ullah MS, Davies AJ, Halestrap AP. The plasma membrane lactate transporter MCT4, but not MCT1, is up-regulated by hypoxia through a HIF-1alpha-dependent mechanism. J Biol Chem 2006; 281:9030-7. [PMID: 16452478 DOI: 10.1074/jbc.m511397200] [Citation(s) in RCA: 664] [Impact Index Per Article: 36.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The monocarboxylate transporter MCT4 mediates lactic acid efflux from most tissues that are dependent on glycolysis for their ATP production. Here we demonstrate that expression of MCT4 mRNA and protein was increased >3-fold by a 48-h exposure to 1% O(2), whereas MCT1 expression was not increased. The effect was mimicked by CoCl(2) (50 microm), suggesting transcriptional regulation by hypoxia-inducible factor 1alpha (HIF-1alpha). The predicted promoters for human MCT1, MCT2, and MCT4 were cloned into the pGL3 vector and shown to be active (luciferase luminescence) under basal conditions. Only the MCT4 promoter was activated (>2-fold) by hypoxia. No response was found in cells lacking HIF-1alpha. Four potential hypoxia-response elements were identified, but deletion analysis implicated only two in the hypoxia response. These were just upstream from the transcription start site and also found in the mouse MCT4 promoter. Mutation of site 2 totally abolished the hypoxic response, whereas mutation of site 1 only reduced the response. Gel-shift analysis demonstrated that nuclear extracts of hypoxic but not normoxic HeLa cells contained two transcription factors that bound to DNA probes containing these hypoxia-response elements. The major shifted band was abolished by mutation of site 2, and supershift analysis confirmed that HIF-1alpha bound to this site. Binding of the second factor was abolished by mutation of site 1. We conclude that MCT4, like other glycolytic enzymes, is up-regulated by hypoxia through a HIF-1alpha-mediated mechanism. This adaptive response allows the increased lactic acid produced during hypoxia to be rapidly lost from the cell.
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Affiliation(s)
- Mohammed S Ullah
- Department of Biochemistry, University of Bristol, School of Medical Sciences, University Walk, Bristol BS8 1TD, United Kingdom
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27
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Cuff MA, Shirazi-Beechey SP. The human monocarboxylate transporter MCT1: gene structure and regulation. Am J Physiol Gastrointest Liver Physiol 2005; 289:G977; author reply G977-9. [PMID: 16227529 DOI: 10.1152/ajpgi.00278.2005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
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28
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Pierre K, Pellerin L. Monocarboxylate transporters in the central nervous system: distribution, regulation and function. J Neurochem 2005; 94:1-14. [PMID: 15953344 DOI: 10.1111/j.1471-4159.2005.03168.x] [Citation(s) in RCA: 472] [Impact Index Per Article: 24.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Monocarboxylate transporters (MCTs) are proton-linked membrane carriers involved in the transport of monocarboxylates such as lactate, pyruvate, as well as ketone bodies. They belong to a larger family of transporters composed of 14 members in mammals based on sequence homologies. MCTs are found in various tissues including the brain where three isoforms, MCT1, MCT2 and MCT4, have been described. Each of these isoforms exhibits a distinct regional and cellular distribution in rodent brain. At the cellular level, MCT1 is expressed by endothelial cells of microvessels, by ependymocytes as well as by astrocytes. MCT4 expression appears to be specific for astrocytes. By contrast, the predominant neuronal monocarboxylate transporter is MCT2. Interestingly, part of MCT2 immunoreactivity is located at postsynaptic sites, suggesting a particular role of monocarboxylates and their transporters in synaptic transmission. In addition to variation in expression during development and upon nutritional modifications, new data indicate that MCT expression is regulated at the translational level by neurotransmitters. Understanding how transport of monocarboxylates is regulated could be of particular importance not only for neuroenergetics but also for areas such as functional brain imaging, regulation of food intake and glucose homeostasis, or for central nervous system disorders such as ischaemia and neurodegenerative diseases.
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Affiliation(s)
- Karin Pierre
- Département de Physiologie, Université de Lausanne, Switzerland
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Hadjiagapiou C, Borthakur A, Dahdal RY, Gill RK, Malakooti J, Ramaswamy K, Dudeja PK. Role of USF1 and USF2 as potential repressor proteins for human intestinal monocarboxylate transporter 1 promoter. Am J Physiol Gastrointest Liver Physiol 2005; 288:G1118-26. [PMID: 15691871 DOI: 10.1152/ajpgi.00312.2004] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Butyrate, a short-chain fatty acid, is the major energy fuel for the colonocytes. We have previously reported that monocarboxylate transporter isoform 1 (MCT1) mediates uptake of butyrate by human colonic Caco-2 cells. To better understand the mechanisms of MCT1 expression and regulation in the human intestine, we examined the activity and regulation of MCT1 promoter in Caco-2 cells. The transcription initiation site in the MCT1 promoter was identified as a guanine nucleotide 281 bp upstream from the translation initiation site and is surrounded by a guanine-cytosine-rich area. The promoter was found to be highly active when transfected into Caco-2 cells, and its activity decreased with deletions at its 5'-end. Gel mobility shift experiments showed binding of the transcription factors upstream stimulatory factor (USF)1 and 2 to the site -114 to -119 of the MCT1 promoter. With the use of site-directed mutagenesis and promoter activity in Caco-2 cells, the USF proteins appeared to have a repressor role on the MCT1 promoter, which was further confirmed by cotransfecting expression vectors encoding USF1 and 2 in Caco-2 cells and determining endogenous MCT1 expression in USF2 overexpressed cells. The two potential SP1 binding sites found in the same region of the promoter were found not to be involved in its regulation.
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Affiliation(s)
- Christos Hadjiagapiou
- Univ. of Illinois at Chicago, Medical Research Service (600/151 Jesse Brown VA Medical Center, 820 South Damen Ave., Chicago, IL 60612, USA
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Cuff MA, Shirazi-Beechey SP. The importance of butyrate transport to the regulation of gene expression in the colonic epithelium. Biochem Soc Trans 2005; 32:1100-2. [PMID: 15506978 DOI: 10.1042/bst0321100] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Butyrate is a naturally occurring monocarboxylate, produced in the lumen of the colon by microbial fermentation of complex carbohydrates that escape digestion in the small intestine. It serves as the principal metabolic fuel for colonic epithelial cells, and exerts a variety of effects important to intestinal health and function. This brief discussion focuses on the route, role and regulation of butyrate transport in the large intestine, with particular emphasis on the significance of butyrate transport to the ability of butyrate to modulate expression of genes important to the processes maintaining colonic tissue homoeostasis.
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Affiliation(s)
- M A Cuff
- Epithelial Function and Development Group, Department of Veterinary Preclinical Sciences, The University of Liverpool, Liverpool L69 7ZJ, UK
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31
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Zhang F, Vannucci SJ, Philp NJ, Simpson IA. Monocarboxylate transporter expression in the spontaneous hypertensive rat: effect of stroke. J Neurosci Res 2005; 79:139-45. [PMID: 15578721 DOI: 10.1002/jnr.20312] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The expression of the monocarboxylate transporters (MCT) 1, 2, and 4 have been studied in the brains of spontaneous hypertensive (SH) rats after an ischemic insult induced by a permanent occlusion of the left middle cerebral artery (MCAO). Profound temporal changes in MCT1 expression were observed in various regions of the ipsilateral hemisphere over the period of 1 hr to 5 days after MCAO. Initially, a very rapid and transient increase in MCT1 mRNA was observed in neurons in the second layer of the cortex and in the piriform cortex at 1-3 hr. A slower but sustained increase in MCT1 mRNA expression was observed in astrocytes in the peri-infarct region beginning at 6 hr after MCAO and persisting over a period of 120 hr coinciding with their activation, migration, and involvement in scar formation. An increase in MCT1 expression in endothelial cells was seen over the same period. These increases in MCT1 expression in astrocytes and endothelial cells were accompanied by a corresponding increase in MCT1 protein. Finally at 120 hr post-MCAO, increases in MCT1, MCT2, and MCT4 expression were observed in cells within the infarct and bordering the scar, the identity of which remains to be determined. Consistent with cell death, the levels of MCT1, MCT2, and MCT4 mRNA decreased with cell death within the infarcted area but unlike MCT1, no increases in either MCT2 or 4 were observed within the remaining ipsilateral hemisphere. These studies reveal that the pattern of regulation of MCT1 expression after MCAO is similar to that observed previously for glucose transporter 1 (GLUT1) and suggest that the regulation of MCT1 mRNA expression is mediated by the hypoxia-inducible transcription factor HIF1.
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Affiliation(s)
- Feng Zhang
- Department of Neural and Behavioral Sciences, Penn State College of Medicine, 500 University Drive, Hershey, PA 17033, USA
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32
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Cuff M, Dyer J, Jones M, Shirazi-Beechey S. The human colonic monocarboxylate transporter Isoform 1: its potential importance to colonic tissue homeostasis. Gastroenterology 2005; 128:676-86. [PMID: 15765403 DOI: 10.1053/j.gastro.2004.12.003] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
BACKGROUND & AIMS Butyrate serves as the major source of energy for colonic epithelial cells, and has profound effects on their proliferation, differentiation, and apoptosis. Transport of butyrate across the colonocyte luminal membrane is mediated by the monocarboxylate transporter, MCT1; the expression of which is down-regulated dramatically during colon carcinogenesis. We have proposed that the decline in MCT1 expression during colon carcinogenesis may reduce the intracellular availability of butyrate required to regulate expression of genes associated with the processes maintaining tissue homeostasis within the colonic mucosa. METHODS To test this hypothesis we used the technique of RNA interference to inhibit MCT1 expression specifically, and determined the consequences of this inhibition on the ability of butyrate to exert its recognized effects in vitro using flow cytometry, immunofluorescence, Northern analysis, and Western analysis. RESULTS We show that inhibition of MCT1 expression, and hence butyrate uptake, has profound inhibitory effects on the ability of butyrate to regulate expression of key target genes: p21waf1/cip1 (p21), intestinal alkaline phosphatase (IAP), and cyclin D1, and their associated processes of proliferation and differentiation. In contrast, inhibition of MCT1 expression had no effect on the ability of butyrate to modulate expression of either bcl-XL or bak, and this was reflected in a corresponding lack of effect on butyrate induction of apoptosis. CONCLUSIONS Collectively, these results show the importance of MCT1 to the ability of butyrate to induce cell-cycle arrest and differentiation, and suggest fundamental differences in the mechanisms by which butyrate modulates specific aspects of cell function.
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Affiliation(s)
- Mark Cuff
- Department of Veterinary Preclinical Sciences, University of Liverpool, Liverpool, United Kingdom
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33
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Transcriptional regulation of intestinal nutrient transporters. MOLECULAR MECHANISMS CONTROLLING TRANSMEMBRANE TRANSPORT 2004. [DOI: 10.1007/b96814] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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Mengual R, El Abida K, Mouaffak N, Rieu M, Beaudry M. Pyruvate shuttle in muscle cells: high-affinity pyruvate transport sites insensitive to trans-lactate efflux. Am J Physiol Endocrinol Metab 2003; 285:E1196-204. [PMID: 12915395 DOI: 10.1152/ajpendo.00034.2003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The specificity of the transport mechanisms for pyruvate and lactate and their sensitivity to inhibitors were studied in L6 skeletal muscle cells. Trans- and cis-lactate effects on pyruvate transport kinetic parameters were examined. Pyruvate and lactate were transported by a multisite carrier system, i.e., by two families of sites, one with low affinity and high capacity (type I sites) and the other with high affinity and low capacity (type II). The multisite character of transport kinetics was not modified by either hydroxycinnamic acid (CIN) or p-chloromercuribenzylsulfonic acid (PCMBS), which exert different types of inhibition. The transport efficiency (TE) ratios of maximal velocity to the trans-activation dissociation constant (Kt) showed that lactate and pyruvate were preferentially transported by types I and II sites, respectively. The cis-lactate effect was observed with high Ki values for both sites. The trans-lactate effect on pyruvate transport occurred only on type I sites and exhibited an asymmetric interaction pattern (Kt of inward lactate > Kt of outward lactate). The inability of lactate to trans-stimulate type II sites suggests that intracellular lactate cannot recruit these sites. The high-affinity type II sites act as a specific pyruvate shuttle and constitute an essential relay for the intracellular lactate shuttle.
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Affiliation(s)
- Raymond Mengual
- Laboratoire de Physiologie des Adaptations, Unité de Formation et de Recherche Cochin Port Royal, Université René Descartes, 75014 Paris, France.
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35
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Enerson BE, Drewes LR. Molecular features, regulation, and function of monocarboxylate transporters: implications for drug delivery. J Pharm Sci 2003; 92:1531-44. [PMID: 12884241 DOI: 10.1002/jps.10389] [Citation(s) in RCA: 135] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The diffusion of monocarboxylates such as lactate and pyruvate across the plasma membrane of mammalian cells is facilitated by a family of integral membrane transport proteins, the monocarboxylate transporters (MCTs). Currently, at least eight unique members of the MCT family have been discovered and orthologs to each have been identified in a variety of species. Four MCTs (MCT1-MCT4) have been functionally characterized. Each isoform possesses unique biochemical properties such as kinetic constants and sensitivity to known MCT inhibitors. Several fold changes in the expression of MCTs may be evoked by altered physiological conditions, yet the molecular mechanisms underlying the regulation of MCTs are poorly understood. Post-translational regulation of MCT1 and MCT4 occurs, in part, by interaction with CD147, an accessory protein that is necessary for trafficking, localization, and functional expression of these transporters. Because of the physiological importance of monocarboxylates to the overall maintenance of metabolic homeostasis, the function of MCTs is significant to several pathologies that occur with disease, such as ischemic stroke and cancer. Finally, the expression of MCT1 in the epithelium of the small intestine and colon and in the blood-brain barrier may provide routes for the intestinal and blood to brain transfer of carboxylated pharmaceutical agents and other exogenous monocarboxylates.
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Affiliation(s)
- Bradley E Enerson
- School of Medicine Duluth, Biochemistry and Molecular Biology, 10 University Drive, Duluth, Minnesota 55812, USA
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36
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McClelland GB, Khanna S, González GF, Butz CE, Brooks GA. Peroxisomal membrane monocarboxylate transporters: evidence for a redox shuttle system? Biochem Biophys Res Commun 2003; 304:130-5. [PMID: 12705896 DOI: 10.1016/s0006-291x(03)00550-3] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
One of the many functions of liver peroxisomes is the beta-oxidation of long-chain fatty acids. It is essential for the continuation of peroxisomal beta-oxidation that a redox shuttle system exist across the peroxisomal membrane to reoxidize NADH. We propose that this redox shuttle system consists of a substrate cycle between lactate and pyruvate. Here we present evidence that purified peroxisomal membranes contain both monocarboxylate transporter 1 (MCT 1) and MCT 2 and that along with peroxisomal lactate dehydrogenase (pLDH) form a Peroxisomal Lactate Shuttle. Peroxisomal beta-oxidation was greatly stimulated by the addition of pyruvate and this increase was partially inhibited by the addition of the MCT blocker alpha-cyano-4-hydroxycinnamate (CINN). We also found that peroxisomes generated lactate in the presence of pyruvate. Together these data provide compelling that the Peroxisome Lactate Shuttle helps maintain organelle redox and the proper functioning of peroxisomal beta-oxidation.
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Affiliation(s)
- Grant B McClelland
- Exercise Physiology Laboratory, Department of Integrative Biology, University of California, Berkeley, CA 94720-3140, USA
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