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Wei H, Cao J, Fallert T, Yeo S, Felmlee MA. GHB toxicokinetics and renal monocarboxylate transporter expression are influenced by the estrus cycle in rats. BMC Pharmacol Toxicol 2023; 24:58. [PMID: 37919807 PMCID: PMC10623699 DOI: 10.1186/s40360-023-00700-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2022] [Accepted: 10/30/2023] [Indexed: 11/04/2023] Open
Abstract
BACKGROUND The illicit use and abuse of gamma-hydroxybutyric acid (GHB) occurs due to its sedative/hypnotic and euphoric effects. Currently, there are no clinically available therapies to treat GHB overdose, and care focuses on symptom treatment until the drug is eliminated from the body. Proton- and sodium-dependent monocarboxylate transporters (MCTs (SLC16A) and SMCTs (SLC5A)) transport and mediate the renal clearance and distribution of GHB. Previously, it has been shown that MCT expression is regulated by sex hormones in the liver, skeletal muscle and Sertoli cells. The focus of the current study is to evaluate GHB toxicokinetics and renal monocarboxylate transporter expression over the estrus cycle in females, and in the absence of male and female sex hormones. METHODS GHB toxicokinetics and renal transporter expression of MCT1, SMCT1 and CD147 were evaluated in females over the estrus cycle, and in ovariectomized (OVX) female, male and castrated (CST) male rats. GHB was administered iv bolus (600 and 1000 mg/kg) and plasma and urine samples were collected for six hours post-dose. GHB concentrations were quantified using a validated LC/MS/MS assay. Transporter mRNA and protein expression was quantified by qPCR and Western Blot. RESULTS GHB renal clearance and AUC varied between sexes and over the estrus cycle in females with higher renal clearance and a lower AUC in proestrus females as compared to males (intact and CST), and OVX females. We demonstrated that renal MCT1 membrane expression varies over the estrus cycle, with the lowest expression observed in proestrus females, which is consistent with the observed changes in GHB renal clearance. CONCLUSIONS Our results suggest that females may be less susceptible to GHB-induced toxicity due to decreased exposure resulting from increased renal clearance, as a result of decreased renal MCT1 expression.
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Affiliation(s)
- Hao Wei
- Department of Pharmaceutics and Medicinal Chemistry, Thomas J Long School of Pharmacy and Health Sciences, University of the Pacific, Stockton, CA, 95211, USA
| | - Jieyun Cao
- Department of Pharmaceutics and Medicinal Chemistry, Thomas J Long School of Pharmacy and Health Sciences, University of the Pacific, Stockton, CA, 95211, USA
- AstraZeneca, Gaithersburg, Maryland, USA
| | - Tyler Fallert
- Department of Pharmaceutics and Medicinal Chemistry, Thomas J Long School of Pharmacy and Health Sciences, University of the Pacific, Stockton, CA, 95211, USA
- Clovis Community Medical Center, Clovis, CA, USA
| | - Su Yeo
- Department of Pharmaceutics and Medicinal Chemistry, Thomas J Long School of Pharmacy and Health Sciences, University of the Pacific, Stockton, CA, 95211, USA
- Kaiser Permanente, Santa Clara, CA, USA
| | - Melanie A Felmlee
- Department of Pharmaceutics and Medicinal Chemistry, Thomas J Long School of Pharmacy and Health Sciences, University of the Pacific, Stockton, CA, 95211, USA.
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The RAGE/multiligand axis: a new actor in tumor biology. Biosci Rep 2022; 42:231455. [PMID: 35727208 PMCID: PMC9251583 DOI: 10.1042/bsr20220395] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Revised: 06/02/2022] [Accepted: 06/21/2022] [Indexed: 01/06/2023] Open
Abstract
The receptor for advanced glycation end-products (RAGE) is a multiligand binding and single-pass transmembrane protein which actively participates in several chronic inflammation-related diseases. RAGE, in addition to AGEs, has a wide repertoire of ligands, including several damage-associated molecular pattern molecules or alarmins such as HMGB1 and members of the S100 family proteins. Over the last years, a large and compelling body of evidence has revealed the active participation of the RAGE axis in tumor biology based on its active involvement in several crucial mechanisms involved in tumor growth, immune evasion, dissemination, as well as by sculpturing of the tumor microenvironment as a tumor-supportive niche. In the present review, we will detail the consequences of the RAGE axis activation to fuel essential mechanisms to guarantee tumor growth and spreading.
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Niu Z, Yang F, Li H, Wang J, Ni Q, Ma C, Zhu H, Chang H, Zhou X, Lu J, Gao H. MCT4 Promotes Hepatocellular Carcinoma Progression by Upregulating TRAPPC5 Gene. J Hepatocell Carcinoma 2022; 9:289-300. [PMID: 35425722 PMCID: PMC9005128 DOI: 10.2147/jhc.s352948] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Accepted: 03/30/2022] [Indexed: 11/23/2022] Open
Affiliation(s)
- Zheyu Niu
- Department of Hepatobiliary Surgery, Shandong Provincial Hospital, Shandong Provincial Hospital Affiliated to Shandong University, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, Shandong, People’s Republic of China
| | - Faji Yang
- Department of Hepatobiliary Surgery, Shandong Provincial Hospital, Shandong Provincial Hospital Affiliated to Shandong University, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, Shandong, People’s Republic of China
| | - Hongguang Li
- Department of Hepatobiliary Surgery, Shandong Provincial Hospital, Shandong Provincial Hospital Affiliated to Shandong University, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, Shandong, People’s Republic of China
| | - Jianlu Wang
- Department of Hepatobiliary Surgery, Shandong Provincial Hospital, Shandong Provincial Hospital Affiliated to Shandong University, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, Shandong, People’s Republic of China
| | - Qingqiang Ni
- Department of Hepatobiliary Surgery, Shandong Provincial Hospital, Shandong Provincial Hospital Affiliated to Shandong University, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, Shandong, People’s Republic of China
| | - Chaoqun Ma
- Department of Hepatobiliary Surgery, Shandong Provincial Hospital, Shandong Provincial Hospital Affiliated to Shandong University, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, Shandong, People’s Republic of China
| | - Huaqiang Zhu
- Department of Hepatobiliary Surgery, Shandong Provincial Hospital, Shandong Provincial Hospital Affiliated to Shandong University, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, Shandong, People’s Republic of China
| | - Hong Chang
- Department of Hepatobiliary Surgery, Shandong Provincial Hospital, Shandong Provincial Hospital Affiliated to Shandong University, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, Shandong, People’s Republic of China
| | - Xu Zhou
- Department of Hepatobiliary Surgery, Shandong Provincial Hospital, Shandong Provincial Hospital Affiliated to Shandong University, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, Shandong, People’s Republic of China
| | - Jun Lu
- Department of Hepatobiliary Surgery, Shandong Provincial Hospital, Shandong Provincial Hospital Affiliated to Shandong University, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, Shandong, People’s Republic of China
- Correspondence: Jun Lu; Hengjun Gao, Department of Hepatobiliary Surgery, Shandong Provincial Hospital, Shandong Provincial Hospital affiliated to Shandong University, Shandong Provincial Hospital affiliated to Shandong First Medical University, Jinan, Shandong, People’s Republic of China, Email ;
| | - Hengjun Gao
- Department of Hepatobiliary Surgery, Shandong Provincial Hospital, Shandong Provincial Hospital Affiliated to Shandong University, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, Shandong, People’s Republic of China
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Hanke-Gogokhia C, Lehmann GL, Benedicto I, de la Fuente-Ortega E, Arshavsky VY, Schreiner R, Rodriguez-Boulan E. Apical CLC-2 in retinal pigment epithelium is crucial for survival of the outer retina. FASEB J 2021; 35:e21689. [PMID: 34085737 PMCID: PMC8252757 DOI: 10.1096/fj.202100349r] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Revised: 04/16/2021] [Accepted: 05/06/2021] [Indexed: 12/15/2022]
Abstract
Knockout of the chloride channel protein 2 (CLC‐2; CLCN2) results in fast progressing blindness in mice. Retinal Pigment Epithelium (RPE) and photoreceptors undergo, in parallel, rapid, and profound morphological changes and degeneration. Immunohistochemistry and electron microscopy of the outer retina and electroretinography of the CLC‐2 KO mouse demonstrated normal morphology at postnatal day 2, followed by drastic changes in RPE and photoreceptor morphology and loss of vision during the first postnatal month. To investigate whether the RPE or the photoreceptors are the primary cause of the degeneration, we injected lentiviruses carrying HA‐tagged CLC‐2 with an RPE‐specific promotor in the subretinal space of CLC‐2‐KO mice at the time of eye opening. As expected, CLC‐2‐HA was expressed exclusively in RPE; strikingly, this procedure rescued the degeneration of both RPE and photoreceptors. Light response in transduced eyes was also recovered. Only a fraction of RPE was transduced with the lentivirus; however, the entire RPE monolayer appears healthy, even the RPE cells not expressing the CLC‐2‐HA. Surprisingly, in contrast with previous physiological observations that postulate that CLC‐2 has a basolateral localization in RPE, our immunofluorescence experiments demonstrated CLC‐2 has an apical distribution, facing the subretinal space and the photoreceptor outer segments. Our findings suggest that CLC‐2 does not play the postulated role in fluid transport at the basolateral membrane. Rather, they suggest that CLC‐2 performs a critical homeostatic role in the subretinal compartment involving a chloride regulatory mechanism that is critical for the survival of both RPE and photoreceptors.
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Affiliation(s)
| | | | - Ignacio Benedicto
- Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain
| | - Erwin de la Fuente-Ortega
- Departamento de Ciencias Biomédicas, Facultad de Medicina, Universidad Católica del Norte, Coquimbo, Chile
| | - Vadim Y Arshavsky
- Department of Ophthalmology, Duke University School of Medicine, Durham, NC, USA
| | - Ryan Schreiner
- Division of Regenerative Medicine, Ansary Stem Cell Institute, Department of Medicine, Weill Cornell Medicine, New York, NY, USA
| | - Enrique Rodriguez-Boulan
- Department of Ophthalmology, Margaret Dyson Vision Research Institute, Weill Cornell Medicine, New York, NY, USA
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Lujan P, Campelo F. Should I stay or should I go? Golgi membrane spatial organization for protein sorting and retention. Arch Biochem Biophys 2021; 707:108921. [PMID: 34038703 DOI: 10.1016/j.abb.2021.108921] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 04/12/2021] [Accepted: 05/03/2021] [Indexed: 12/23/2022]
Abstract
The Golgi complex is the membrane-bound organelle that lies at the center of the secretory pathway. Its main functions are to maintain cellular lipid homeostasis, to orchestrate protein processing and maturation, and to mediate protein sorting and export. These functions are not independent of one another, and they all require that the membranes of the Golgi complex have a well-defined biochemical composition. Importantly, a finely-regulated spatiotemporal organization of the Golgi membrane components is essential for the correct performance of the organelle. In here, we review our current mechanistic and molecular understanding of how Golgi membranes are spatially organized in the lateral and axial directions to fulfill their functions. In particular, we highlight the current evidence and proposed models of intra-Golgi transport, as well as the known mechanisms for the retention of Golgi residents and for the sorting and export of transmembrane cargo proteins. Despite the controversies, conflicting evidence, clashes between models, and technical limitations, the field has moved forward and we have gained extensive knowledge in this fascinating topic. However, there are still many important questions that remain to be completely answered. We hope that this review will help boost future investigations on these issues.
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Affiliation(s)
- Pablo Lujan
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860, Barcelona, Spain.
| | - Felix Campelo
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860, Barcelona, Spain.
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Fairweather SJ, Shah N, Brӧer S. Heteromeric Solute Carriers: Function, Structure, Pathology and Pharmacology. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 21:13-127. [PMID: 33052588 DOI: 10.1007/5584_2020_584] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Solute carriers form one of three major superfamilies of membrane transporters in humans, and include uniporters, exchangers and symporters. Following several decades of molecular characterisation, multiple solute carriers that form obligatory heteromers with unrelated subunits are emerging as a distinctive principle of membrane transporter assembly. Here we comprehensively review experimentally established heteromeric solute carriers: SLC3-SLC7 amino acid exchangers, SLC16 monocarboxylate/H+ symporters and basigin/embigin, SLC4A1 (AE1) and glycophorin A exchanger, SLC51 heteromer Ost α-Ost β uniporter, and SLC6 heteromeric symporters. The review covers the history of the heteromer discovery, transporter physiology, structure, disease associations and pharmacology - all with a focus on the heteromeric assembly. The cellular locations, requirements for complex formation, and the functional role of dimerization are extensively detailed, including analysis of the first complete heteromer structures, the SLC7-SLC3 family transporters LAT1-4F2hc, b0,+AT-rBAT and the SLC6 family heteromer B0AT1-ACE2. We present a systematic analysis of the structural and functional aspects of heteromeric solute carriers and conclude with common principles of their functional roles and structural architecture.
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Affiliation(s)
- Stephen J Fairweather
- Research School of Biology, Australian National University, Canberra, ACT, Australia. .,Resarch School of Chemistry, Australian National University, Canberra, ACT, Australia.
| | - Nishank Shah
- Research School of Biology, Australian National University, Canberra, ACT, Australia
| | - Stefan Brӧer
- Research School of Biology, Australian National University, Canberra, ACT, Australia.
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7
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Klipfel L, Cordonnier M, Thiébault L, Clérin E, Blond F, Millet-Puel G, Mohand-Saïd S, Goureau O, Sahel JA, Nandrot EF, Léveillard T. A Splice Variant in SLC16A8 Gene Leads to Lactate Transport Deficit in Human iPS Cell-Derived Retinal Pigment Epithelial Cells. Cells 2021; 10:cells10010179. [PMID: 33477551 PMCID: PMC7831140 DOI: 10.3390/cells10010179] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Revised: 01/05/2021] [Accepted: 01/15/2021] [Indexed: 12/27/2022] Open
Abstract
Age-related macular degeneration (AMD) is a blinding disease for which most of the patients remain untreatable. Since the disease affects the macula at the center of the retina, a structure specific to the primate lineage, rodent models to study the pathophysiology of AMD and to develop therapies are very limited. Consequently, our understanding relies mostly on genetic studies highlighting risk alleles at many loci. We are studying the possible implication of a metabolic imbalance associated with risk alleles within the SLC16A8 gene that encodes for a retinal pigment epithelium (RPE)-specific lactate transporter MCT3 and its consequences for vision. As a first approach, we report here the deficit in transepithelial lactate transport of a rare SLC16A8 allele identified during a genome-wide association study. We produced induced pluripotent stem cells (iPSCs) from the unique patient in our cohort that carries two copies of this allele. After in vitro differentiation of the iPSCs into RPE cells and their characterization, we demonstrate that the rare allele results in the retention of intron 2 of the SLC16A8 gene leading to the absence of MCT3 protein. We show using a biochemical assay that these cells have a deficit in transepithelial lactate transport.
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Affiliation(s)
- Laurence Klipfel
- Institut de la Vision, Sorbonne Université, INSERM, CNRS, 17 rue Moreau, F-75012 Paris, France; (L.K.); (M.C.); (L.T.); (E.C.); (F.B.); (G.M.-P.); (O.G.); (J.-A.S.); (E.F.N.)
| | - Marie Cordonnier
- Institut de la Vision, Sorbonne Université, INSERM, CNRS, 17 rue Moreau, F-75012 Paris, France; (L.K.); (M.C.); (L.T.); (E.C.); (F.B.); (G.M.-P.); (O.G.); (J.-A.S.); (E.F.N.)
| | - Léa Thiébault
- Institut de la Vision, Sorbonne Université, INSERM, CNRS, 17 rue Moreau, F-75012 Paris, France; (L.K.); (M.C.); (L.T.); (E.C.); (F.B.); (G.M.-P.); (O.G.); (J.-A.S.); (E.F.N.)
| | - Emmanuelle Clérin
- Institut de la Vision, Sorbonne Université, INSERM, CNRS, 17 rue Moreau, F-75012 Paris, France; (L.K.); (M.C.); (L.T.); (E.C.); (F.B.); (G.M.-P.); (O.G.); (J.-A.S.); (E.F.N.)
| | - Frédéric Blond
- Institut de la Vision, Sorbonne Université, INSERM, CNRS, 17 rue Moreau, F-75012 Paris, France; (L.K.); (M.C.); (L.T.); (E.C.); (F.B.); (G.M.-P.); (O.G.); (J.-A.S.); (E.F.N.)
| | - Géraldine Millet-Puel
- Institut de la Vision, Sorbonne Université, INSERM, CNRS, 17 rue Moreau, F-75012 Paris, France; (L.K.); (M.C.); (L.T.); (E.C.); (F.B.); (G.M.-P.); (O.G.); (J.-A.S.); (E.F.N.)
| | - Saddek Mohand-Saïd
- CHNO des Quinze-Vingts, INSERM-DGOS CIC 1423, 28 rue de Charenton, F-75012 Paris, France;
| | - Olivier Goureau
- Institut de la Vision, Sorbonne Université, INSERM, CNRS, 17 rue Moreau, F-75012 Paris, France; (L.K.); (M.C.); (L.T.); (E.C.); (F.B.); (G.M.-P.); (O.G.); (J.-A.S.); (E.F.N.)
| | - José-Alain Sahel
- Institut de la Vision, Sorbonne Université, INSERM, CNRS, 17 rue Moreau, F-75012 Paris, France; (L.K.); (M.C.); (L.T.); (E.C.); (F.B.); (G.M.-P.); (O.G.); (J.-A.S.); (E.F.N.)
- CHNO des Quinze-Vingts, INSERM-DGOS CIC 1423, 28 rue de Charenton, F-75012 Paris, France;
| | - Emeline F. Nandrot
- Institut de la Vision, Sorbonne Université, INSERM, CNRS, 17 rue Moreau, F-75012 Paris, France; (L.K.); (M.C.); (L.T.); (E.C.); (F.B.); (G.M.-P.); (O.G.); (J.-A.S.); (E.F.N.)
| | - Thierry Léveillard
- Institut de la Vision, Sorbonne Université, INSERM, CNRS, 17 rue Moreau, F-75012 Paris, France; (L.K.); (M.C.); (L.T.); (E.C.); (F.B.); (G.M.-P.); (O.G.); (J.-A.S.); (E.F.N.)
- Correspondence: ; Tel.: +33-153-462-548
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Storm T, Burgoyne T, Futter CE. Membrane trafficking in the retinal pigment epithelium at a glance. J Cell Sci 2020; 133:133/16/jcs238279. [PMID: 32855284 DOI: 10.1242/jcs.238279] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The retinal pigment epithelium (RPE) is a highly specialised pigmented monolayer sandwiched between the choroid and the photoreceptors in the retina. Key functions of the RPE include transport of nutrients to the neural retina, removal of waste products and water from the retina to the blood, recycling of retinal chromophores, absorption of scattered light and phagocytosis of the tips of the photoreceptor outer segments. These functions place a considerable membrane trafficking burden on the RPE. In this Cell Science at a Glance article and the accompanying poster, we focus on RPE-specific adaptations of trafficking pathways. We outline mechanisms underlying the polarised expression of membrane proteins, melanosome biogenesis and movement, and endocytic trafficking, as well as photoreceptor outer segment phagocytosis and degradation. We also briefly discuss theories of how dysfunction in trafficking pathways contributes to retinal disease.
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Affiliation(s)
- Tina Storm
- Institute of Ophthalmology, University College London, London EC1V 9EL, UK
| | - Thomas Burgoyne
- Institute of Ophthalmology, University College London, London EC1V 9EL, UK
| | - Clare E Futter
- Institute of Ophthalmology, University College London, London EC1V 9EL, UK
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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: 162] [Impact Index Per Article: 40.5] [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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10
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Han JYS, Kinoshita J, Bisetto S, Bell BA, Nowak RA, Peachey NS, Philp NJ. Role of monocarboxylate transporters in regulating metabolic homeostasis in the outer retina: Insight gained from cell-specific Bsg deletion. FASEB J 2020; 34:5401-5419. [PMID: 32112484 DOI: 10.1096/fj.201902961r] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 01/29/2020] [Accepted: 02/07/2020] [Indexed: 02/06/2023]
Abstract
The neural retina metabolizes glucose through aerobic glycolysis generating large amounts of lactate. Lactate flux into and out of cells is regulated by proton-coupled monocarboxylate transporters (MCTs), which are encoded by members of the Slc16a family. MCT1, MCT3, and MCT4 are expressed in the retina and require association with the accessory protein basigin, encoded by Bsg, for maturation and trafficking to the plasma membrane. Bsg-/- mice have severely reduced electroretinograms (ERGs) and progressive photoreceptor degeneration, which is presumed to be driven by metabolic dysfunction resulting from loss of MCTs. To understand the basis of the Bsg-/- phenotype, we generated mice with conditional deletion of Bsg in rods (RodΔBsg), cones (Cone∆Bsg), or retinal pigment epithelial cells (RPEΔBsg). RodΔBsg mice showed a progressive loss of photoreceptors, while ConeΔBsg mice did not display a degenerative phenotype. The RPEΔBsg mice developed a distinct phenotype characterized by severely reduced ERG responses as early as 4 weeks of age. The loss of lactate transporters from the RPE most closely resembled the phenotype of the Bsg-/- mouse, suggesting that the regulation of lactate levels in the RPE and the subretinal space is essential for the viability and function of photoreceptors.
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Affiliation(s)
- John Y S Han
- Department of Pathology, Anatomy, & Cell Biology, Thomas Jefferson University, Philadelphia, PA, USA
| | | | - Sara Bisetto
- Department of Pathology, Anatomy, & Cell Biology, Thomas Jefferson University, Philadelphia, PA, USA
| | - Brent A Bell
- Department of Ophthalmology, University of Pennsylvania, Philadelphia, PA, USA
| | - Romana A Nowak
- Animal Sciences, University of Illinois at Urbana-Champaign, Urbana-Champaign, IL, USA
| | - Neal S Peachey
- Cole Eye Institute, Cleveland Clinic, Cleveland, OH, USA.,Louis Stokes Cleveland VA Medical Center, Cleveland, OH, USA.,Department of Ophthalmology, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, OH, USA
| | - Nancy J Philp
- Department of Pathology, Anatomy, & Cell Biology, Thomas Jefferson University, Philadelphia, PA, USA
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11
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Lakkaraju A, Umapathy A, Tan LX, Daniele L, Philp NJ, Boesze-Battaglia K, Williams DS. The cell biology of the retinal pigment epithelium. Prog Retin Eye Res 2020; 78:100846. [PMID: 32105772 PMCID: PMC8941496 DOI: 10.1016/j.preteyeres.2020.100846] [Citation(s) in RCA: 170] [Impact Index Per Article: 42.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Revised: 02/19/2020] [Accepted: 02/23/2020] [Indexed: 02/07/2023]
Abstract
The retinal pigment epithelium (RPE), a monolayer of post-mitotic polarized epithelial cells, strategically situated between the photoreceptors and the choroid, is the primary caretaker of photoreceptor health and function. Dysfunction of the RPE underlies many inherited and acquired diseases that cause permanent blindness. Decades of research have yielded valuable insight into the cell biology of the RPE. In recent years, new technologies such as live-cell imaging have resulted in major advancement in our understanding of areas such as the daily phagocytosis and clearance of photoreceptor outer segment tips, autophagy, endolysosome function, and the metabolic interplay between the RPE and photoreceptors. In this review, we aim to integrate these studies with an emphasis on appropriate models and techniques to investigate RPE cell biology and metabolism, and discuss how RPE cell biology informs our understanding of retinal disease.
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Affiliation(s)
- Aparna Lakkaraju
- Department of Ophthalmology, University of California, San Francisco, San Francisco, CA, USA
| | - Ankita Umapathy
- Department of Ophthalmology and Stein Eye Institute, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA; Department of Neurobiology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Li Xuan Tan
- Department of Ophthalmology, University of California, San Francisco, San Francisco, CA, USA
| | - Lauren Daniele
- Department of Biochemistry, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Nancy J Philp
- Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA, USA
| | - Kathleen Boesze-Battaglia
- Department of Biochemistry, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - David S Williams
- Department of Ophthalmology and Stein Eye Institute, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA; Department of Neurobiology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA.
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12
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Di Martino R, Sticco L, Luini A. Regulation of cargo export and sorting at the trans‐Golgi network. FEBS Lett 2019; 593:2306-2318. [DOI: 10.1002/1873-3468.13572] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Revised: 08/02/2019] [Accepted: 08/06/2019] [Indexed: 12/28/2022]
Affiliation(s)
- Rosaria Di Martino
- Institute of Biochemistry and Cell Biology (IBBC) Italian National Research Council (CNR) Naples Italy
| | - Lucia Sticco
- Institute of Biochemistry and Cell Biology (IBBC) Italian National Research Council (CNR) Naples Italy
| | - Alberto Luini
- Institute of Biochemistry and Cell Biology (IBBC) Italian National Research Council (CNR) Naples Italy
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13
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Zhang S, Xu W, Wang H, Cao M, Li M, Zhao J, Hu Y, Wang Y, Li S, Xie Y, Chen G, Liu R, Cheng Y, Xu Z, Zou K, Gong S, Geng L. Inhibition of CREB-mediated ZO-1 and activation of NF-κB-induced IL-6 by colonic epithelial MCT4 destroys intestinal barrier function. Cell Prolif 2019; 52:e12673. [PMID: 31418947 PMCID: PMC6869122 DOI: 10.1111/cpr.12673] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2019] [Revised: 06/13/2019] [Accepted: 07/07/2019] [Indexed: 02/06/2023] Open
Abstract
Objective Inflammatory bowel disease (IBD) is a disorder intestinal inflammation and impaired barrier function, associated with increased epithelial expression of monocarboxylate transporter 4 (MCT4). However, the specific non‐metabolic function and clinical relevance of MCT4 in IBD remain to be fully elucidated. Methods Lentivirus‐mediated overexpression of MCT4 was used to assess the role of MCT4 in transcriptionally regulating ZO‐1 and IL‐6 expression by luciferase assays, WB and ChIP. IP was used to analyse the effect of MCT4 on the interaction NF‐κB‐CBP or CREB‐CBP, and these MCT4‐mediated effects were confirmed in vivo assay. Results We showed that ectopic expression of MCT4 inhibited ZO‐1 expression, while increased pro‐inflammatory factors expression, leading to destroy intestinal epithelial barrier function in vitro and in vivo. Mechanistically, MCT4 contributed NF‐κB p65 nuclear translocation and increased the binding of NF‐κB p65 to the promoter of IL‐6, which is attributed to MCT4 enhanced NF‐κB‐CBP interaction and dissolved CREB‐CBP complex, resulting in reduction of CREB activity and CREB‐mediated ZO‐1 expression. In addition, treatment of experimental colitis with MCT4 inhibitor α‐cyano‐4‐hydroxycinnamate (CHC) ameliorated mucosal intestinal barrier function, which was due to attenuation of pro‐inflammation factors expression and enhancement of ZO‐1 expression. Conclusion These findings suggested a novel role of MCT4 in controlling development of IBD and provided evidence for potential targets of IBD.
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Affiliation(s)
- Shunxian Zhang
- Guangzhou Institute of Pediatrics, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, China.,Department of Gastroenterology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, China
| | - Wanfu Xu
- Guangzhou Institute of Pediatrics, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, China.,Department of Gastroenterology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, China
| | - Hongli Wang
- Department of Gastroenterology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, China
| | - Meiwan Cao
- Department of Gastroenterology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, China
| | - Musheng Li
- Department of Gastroenterology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, China
| | - Junhong Zhao
- Department of Gastroenterology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, China
| | - Yan Hu
- Department of Anesthesiology, Hainan General Hospital, Haikou, China
| | - Yaodong Wang
- Department of Gastroenterology, Kunshan affiliated Hospital of Nanjing University of Chinese Medicine, Kunshan, China
| | - Songyu Li
- Department of Clinical Laboratory, Qionghai Hospital of Traditional Chinese Medicine, Qionghai, China
| | - Yuanwen Xie
- Department of Anorectal, Qionghai Hospital of Traditional Chinese Medicine, Qionghai, China
| | - Guanhua Chen
- Department of Gastroenterology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, China
| | - Ruitao Liu
- Department of Gastroenterology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, China
| | - Yang Cheng
- Guangzhou Institute of Pediatrics, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, China.,Department of Gastroenterology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, China
| | - Zhaohui Xu
- Department of Gastroenterology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, China
| | - Kejian Zou
- Department of General Surgery, Hainan General Hospital, Haikou, China
| | - Sitang Gong
- Guangzhou Institute of Pediatrics, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, China.,Department of Gastroenterology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, China
| | - Lanlan Geng
- Guangzhou Institute of Pediatrics, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, China.,Department of Gastroenterology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, China
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14
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Park SJ, Smith CP, Wilbur RR, Cain CP, Kallu SR, Valasapalli S, Sahoo A, Guda MR, Tsung AJ, Velpula KK. An overview of MCT1 and MCT4 in GBM: small molecule transporters with large implications. Am J Cancer Res 2018; 8:1967-1976. [PMID: 30416849 PMCID: PMC6220151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Accepted: 09/20/2018] [Indexed: 06/09/2023] Open
Abstract
Monocarboxylate transporters (MCTs) represent a diverse group of transmembrane proteins encoded by the SLC16 gene family found ubiquitously across mammalian species. Two members of this family, MCT1 and MCT4, have been linked to key roles in the metabolic activity of tissues through the proton-coupled transport of monocarboxylates, most notably L-lactate, ketone bodies, and pyruvate. This review aims to provide an overview of MCT1 and MCT4, followed by the implications of their expression in a multitude of cancers and in glioblastoma (GBM) specifically. Further, the possible mechanisms underlying these effects will be discussed. Given the relationships between MCT1 and MCT4 and cancer, they offer a unique opportunity for novel treatment strategies. We aim to explore current therapies focused on MCT1 and MCT4 and propose future studies to better understand their role in GBM to optimize future treatment regimens.
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Affiliation(s)
- Simon J Park
- Department of Cancer Biology and Pharmacology, University of Illinois College of Medicine at PeoriaPeoria, IL, USA
| | - Chase P Smith
- Department of Cancer Biology and Pharmacology, University of Illinois College of Medicine at PeoriaPeoria, IL, USA
| | - Ryan R Wilbur
- Department of Cancer Biology and Pharmacology, University of Illinois College of Medicine at PeoriaPeoria, IL, USA
| | - Charles P Cain
- Department of Cancer Biology and Pharmacology, University of Illinois College of Medicine at PeoriaPeoria, IL, USA
| | - Sankeerth R Kallu
- Department of Cancer Biology and Pharmacology, University of Illinois College of Medicine at PeoriaPeoria, IL, USA
| | - Srijan Valasapalli
- Department of Cancer Biology and Pharmacology, University of Illinois College of Medicine at PeoriaPeoria, IL, USA
| | - Arpit Sahoo
- Department of Cancer Biology and Pharmacology, University of Illinois College of Medicine at PeoriaPeoria, IL, USA
| | - Maheedhara R Guda
- Department of Cancer Biology and Pharmacology, University of Illinois College of Medicine at PeoriaPeoria, IL, USA
| | - Andrew J Tsung
- Department of Cancer Biology and Pharmacology, University of Illinois College of Medicine at PeoriaPeoria, IL, USA
- Department of Neurosurgery, University of Illinois College of Medicine at PeoriaPeoria, IL, USA
- Illinois Neurological InstitutePeoria, IL, USA
| | - Kiran K Velpula
- Department of Cancer Biology and Pharmacology, University of Illinois College of Medicine at PeoriaPeoria, IL, USA
- Department of Neurosurgery, University of Illinois College of Medicine at PeoriaPeoria, IL, USA
- Department of Pediatrics, University of Illinois College of Medicine at PeoriaPeoria, IL, USA
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15
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Knöpfel T, Atanassoff A, Hernando N, Biber J, Wagner CA. Renal localization and regulation by dietary phosphate of the MCT14 orphan transporter. PLoS One 2017; 12:e0177942. [PMID: 28662032 PMCID: PMC5490967 DOI: 10.1371/journal.pone.0177942] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Accepted: 05/05/2017] [Indexed: 01/15/2023] Open
Abstract
MCT14 is an orphan transporter belonging to the SLC16 transporter family mediating the transport of monocarboxylates, aromatic amino acids, creatine, and thyroid hormones. The expression, tissue localization, regulation, and function of MCT14 are unknown. In mouse MCT14 mRNA abundance is highest in kidney. Using a newly developed and validated antibody, MCT14 was localized to the luminal membrane of the thick ascending limb of the loop of Henle colocalizing in the same cells with uromodulin and NKCC2. MCT14 mRNA and protein was found to be highly regulated by dietary phosphate intake in mice being increased by high dietary phosphate intake at both mRNA and protein level. In order to identify the transport substrate(s), we expressed MCT14 in Xenopus laevis oocytes where MCT14 was integrated into the plasma membrane. However, no transport was discovered for the classic substrates of the SLC16 family nor for phosphate. In summary, MCT14 is an orphan transporter regulated by phosphate and highly enriched in kidney localizing to the luminal membrane of one specific nephron segment.
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Affiliation(s)
- Thomas Knöpfel
- Institute of Physiology, University of Zurich, Zurich, Switzerland
- NCCR Kidney.CH, Switzerland
| | - Alexander Atanassoff
- Institute of Physiology, University of Zurich, Zurich, Switzerland
- NCCR Kidney.CH, Switzerland
| | - Nati Hernando
- Institute of Physiology, University of Zurich, Zurich, Switzerland
- NCCR Kidney.CH, Switzerland
| | - Jürg Biber
- Institute of Physiology, University of Zurich, Zurich, Switzerland
- NCCR Kidney.CH, Switzerland
| | - Carsten A. Wagner
- Institute of Physiology, University of Zurich, Zurich, Switzerland
- NCCR Kidney.CH, Switzerland
- * E-mail:
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16
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Caceres PS, Benedicto I, Lehmann GL, Rodriguez-Boulan EJ. Directional Fluid Transport across Organ-Blood Barriers: Physiology and Cell Biology. Cold Spring Harb Perspect Biol 2017; 9:a027847. [PMID: 28003183 PMCID: PMC5334253 DOI: 10.1101/cshperspect.a027847] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Directional fluid flow is an essential process for embryo development as well as for organ and organism homeostasis. Here, we review the diverse structure of various organ-blood barriers, the driving forces, transporters, and polarity mechanisms that regulate fluid transport across them, focusing on kidney-, eye-, and brain-blood barriers. We end by discussing how cross talk between barrier epithelial and endothelial cells, perivascular cells, and basement membrane signaling contribute to generate and maintain organ-blood barriers.
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Affiliation(s)
- Paulo S Caceres
- Margaret Dyson Vision Research Institute, Department of Ophthalmology, Weill Cornell Medical College, New York, New York 10065
| | - Ignacio Benedicto
- Margaret Dyson Vision Research Institute, Department of Ophthalmology, Weill Cornell Medical College, New York, New York 10065
| | - Guillermo L Lehmann
- Margaret Dyson Vision Research Institute, Department of Ophthalmology, Weill Cornell Medical College, New York, New York 10065
| | - Enrique J Rodriguez-Boulan
- Margaret Dyson Vision Research Institute, Department of Ophthalmology, Weill Cornell Medical College, New York, New York 10065
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17
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Lobato-Álvarez JA, Roldán ML, López-Murillo TDC, González-Ramírez R, Bonilla-Delgado J, Shoshani L. The Apical Localization of Na +, K +-ATPase in Cultured Human Retinal Pigment Epithelial Cells Depends on Expression of the β 2 Subunit. Front Physiol 2016; 7:450. [PMID: 27774068 PMCID: PMC5054689 DOI: 10.3389/fphys.2016.00450] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2016] [Accepted: 09/20/2016] [Indexed: 11/28/2022] Open
Abstract
Na+, K+-ATPase, or the Na+ pump, is a key component in the maintenance of the epithelial phenotype. In most epithelia, the pump is located in the basolateral domain. Studies from our laboratory have shown that the β1 subunit of Na+, K+-ATPase plays an important role in this mechanism because homotypic β1-β1 interactions between neighboring cells stabilize the pump in the lateral membrane. However, in the retinal pigment epithelium (RPE), the Na+ pump is located in the apical domain. The mechanism of polarization in this epithelium is unclear. We hypothesized that the apical polarization of the pump in RPE cells depends on the expression of its β2 subunit. ARPE-19 cells cultured for up to 8 weeks on inserts did not polarize, and Na+, K+-ATPase was expressed in the basolateral membrane. In the presence of insulin, transferrin and selenic acid (ITS), ARPE-19 cells cultured for 4 weeks acquired an RPE phenotype, and the Na+ pump was visible in the apical domain. Under these conditions, Western blot analysis was employed to detect the β2 isoform and immunofluorescence analysis revealed an apparent apical distribution of the β2 subunit. qPCR results showed a time-dependent increase in the level of β2 isoform mRNA, suggesting regulation at the transcriptional level. Moreover, silencing the expression of the β2 isoform in ARPE-19 cells resulted in a decrease in the apical localization of the pump, as assessed by the mislocalization of the α2 subunit in that domain. Our results demonstrate that the apical polarization of Na+, K+-ATPase in RPE cells depends on the expression of the β2 subunit.
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Affiliation(s)
- Jorge A Lobato-Álvarez
- Laboratory of Epithelial Research, Department of Physiology, Biophysics and Neurosciences, CINVESTAV-IPN México City, Mexico
| | - María L Roldán
- Laboratory of Epithelial Research, Department of Physiology, Biophysics and Neurosciences, CINVESTAV-IPN México City, Mexico
| | - Teresa Del Carmen López-Murillo
- Laboratory of Epithelial Research, Department of Physiology, Biophysics and Neurosciences, CINVESTAV-IPN México City, Mexico
| | - Ricardo González-Ramírez
- Department of Molecular Biology and Histocompatibility, Hospital General Dr. Manuel Gea González México City, Mexico
| | - José Bonilla-Delgado
- Research Unit, Laboratory of Genetics and Molecular Diagnosis, Hospital Juárez de México México City, Mexico
| | - Liora Shoshani
- Laboratory of Epithelial Research, Department of Physiology, Biophysics and Neurosciences, CINVESTAV-IPN México City, Mexico
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18
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Al-Mosauwi H, Ryan E, McGrane A, Riveros-Beltran S, Walpole C, Dempsey E, Courtney D, Fearon N, Winter D, Baird A, Stewart G. Differential protein abundance of a basolateral MCT1 transporter in the human gastrointestinal tract. Cell Biol Int 2016; 40:1303-1312. [PMID: 27634412 DOI: 10.1002/cbin.10684] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Accepted: 09/05/2016] [Indexed: 11/06/2022]
Abstract
Bacterially derived short chain fatty acids (SCFAs), such as butyrate, are vital in maintaining the symbiotic relationship that exists between humans and their gastrointestinal microbial populations. A key step in this process is the transport of SCFAs across colonic epithelial cells via MCT1 transporters. This study investigated MCT1 protein abundance in various human intestinal tissues. Initial RT-PCR analysis confirmed the expected MCT1 RNA expression pattern of colon > small intestine > stomach. Using surgical resection samples, immunoblot analysis detected higher abundance of a 45 kDa MCT1 protein in colonic tissue compared to ileum tissue (P < 0.001, N = 4, unpaired t-test). Importantly, MCT1 abundance was found to be significantly lower in sigmoid colon compared to ascending colon (P < 0.01, N = 8-11, ANOVA). Finally, immunolocalization studies confirmed MCT1 to be abundant in the basolateral membranes of surface epithelial cells of the ascending, transverse, and descending colon, but significantly less prevalent in the sigmoid colon (P < 0.05, N = 5-21, ANOVA). In conclusion, these data confirm that basolateral MCT1 protein abundance is correlated to levels of bacterially derived SCFAs along the human gastrointestinal tract. These findings highlight the importance of precise tissue location in studies comparing colonic MCT1 abundance between normal and diseased states.
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Affiliation(s)
- Hashemeya Al-Mosauwi
- School of Biology and Environmental Science, Science Centre West, University College Dublin, Room 2.55, Belfield, Dublin 4, Ireland
| | - Elizabeth Ryan
- Institute for Clinical Outcomes Research and Education, St.Vincent's University Hospital, Dublin, Ireland.,College of Life Sciences and Conway Institute of Biomedical and Biomolecular Science, University College Dublin, Dublin, Ireland
| | - Alison McGrane
- School of Biology and Environmental Science, Science Centre West, University College Dublin, Room 2.55, Belfield, Dublin 4, Ireland
| | - Stefanie Riveros-Beltran
- School of Biology and Environmental Science, Science Centre West, University College Dublin, Room 2.55, Belfield, Dublin 4, Ireland
| | - Caragh Walpole
- School of Biology and Environmental Science, Science Centre West, University College Dublin, Room 2.55, Belfield, Dublin 4, Ireland
| | - Eugene Dempsey
- School of Biology and Environmental Science, Science Centre West, University College Dublin, Room 2.55, Belfield, Dublin 4, Ireland
| | - Danielle Courtney
- Institute for Clinical Outcomes Research and Education, St.Vincent's University Hospital, Dublin, Ireland.,College of Life Sciences and Conway Institute of Biomedical and Biomolecular Science, University College Dublin, Dublin, Ireland
| | - Naomi Fearon
- Institute for Clinical Outcomes Research and Education, St.Vincent's University Hospital, Dublin, Ireland.,College of Life Sciences and Conway Institute of Biomedical and Biomolecular Science, University College Dublin, Dublin, Ireland
| | - Desmond Winter
- Institute for Clinical Outcomes Research and Education, St.Vincent's University Hospital, Dublin, Ireland
| | - Alan Baird
- College of Life Sciences and Conway Institute of Biomedical and Biomolecular Science, University College Dublin, Dublin, Ireland
| | - Gavin Stewart
- School of Biology and Environmental Science, Science Centre West, University College Dublin, Room 2.55, Belfield, Dublin 4, Ireland
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19
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Uggenti C, Briant K, Streit AK, Thomson S, Koay YH, Baines RA, Swanton E, Manson FD. Restoration of mutant bestrophin-1 expression, localisation and function in a polarised epithelial cell model. Dis Model Mech 2016; 9:1317-1328. [PMID: 27519691 PMCID: PMC5117222 DOI: 10.1242/dmm.024216] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2015] [Accepted: 07/21/2016] [Indexed: 01/13/2023] Open
Abstract
Autosomal recessive bestrophinopathy (ARB) is a retinopathy caused by mutations in the bestrophin-1 protein, which is thought to function as a Ca2+-gated Cl− channel in the basolateral surface of the retinal pigment epithelium (RPE). Using a stably transfected polarised epithelial cell model, we show that four ARB mutant bestrophin-1 proteins were mislocalised and subjected to proteasomal degradation. In contrast to the wild-type bestrophin-1, each of the four mutant proteins also failed to conduct Cl− ions in transiently transfected cells as determined by whole-cell patch clamp. We demonstrate that a combination of two clinically approved drugs, bortezomib and 4-phenylbutyrate (4PBA), successfully restored the expression and localisation of all four ARB mutant bestrophin-1 proteins. Importantly, the Cl− conductance function of each of the mutant bestrophin-1 proteins was fully restored to that of wild-type bestrophin-1 by treatment of cells with 4PBA alone. The functional rescue achieved with 4PBA is significant because it suggests that this drug, which is already approved for long-term use in infants and adults, might represent a promising therapy for the treatment of ARB and other bestrophinopathies resulting from missense mutations in BEST1. Summary: Chemical chaperone 4PBA fully restores Cl− conductance activity for mutant bestrophin-1 proteins associated with inherited retinal dystrophy, autosomal recessive bestrophinopathy.
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Affiliation(s)
- Carolina Uggenti
- Faculty of Biology, Medicine and Health, The University of Manchester, Manchester M13 9PT, UK
| | - Kit Briant
- Faculty of Biology, Medicine and Health, The University of Manchester, Manchester M13 9PT, UK
| | - Anne-Kathrin Streit
- Faculty of Biology, Medicine and Health, The University of Manchester, Manchester M13 9PT, UK
| | - Steven Thomson
- Faculty of Biology, Medicine and Health, The University of Manchester, Manchester M13 9PT, UK
| | - Yee Hui Koay
- Faculty of Biology, Medicine and Health, The University of Manchester, Manchester M13 9PT, UK
| | - Richard A Baines
- Faculty of Biology, Medicine and Health, The University of Manchester, Manchester M13 9PT, UK
| | - Eileithyia Swanton
- Faculty of Biology, Medicine and Health, The University of Manchester, Manchester M13 9PT, UK
| | - Forbes D Manson
- Faculty of Biology, Medicine and Health, The University of Manchester, Manchester M13 9PT, UK
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20
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Ziegler K, Kerimi A, Poquet L, Williamson G. Butyric acid increases transepithelial transport of ferulic acid through upregulation of the monocarboxylate transporters SLC16A1 (MCT1) and SLC16A3 (MCT4). Arch Biochem Biophys 2016; 599:3-12. [PMID: 26854723 PMCID: PMC4884672 DOI: 10.1016/j.abb.2016.01.018] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Revised: 01/27/2016] [Accepted: 01/29/2016] [Indexed: 12/21/2022]
Abstract
Ferulic acid is released by microbial hydrolysis in the colon, where butyric acid, a major by-product of fermentation, constitutes the main energy source for colonic enterocytes. We investigated how varying concentrations of this short chain fatty acid may influence the absorption of the phenolic acid. Chronic treatment of Caco-2 cells with butyric acid resulted in increased mRNA and protein abundance of the monocarboxylate transporters SLC16A1 (MCT1) and SLC16A3 (MCT4), previously proposed to facilitate ferulic acid absorption in addition to passive diffusion. Short term incubation with butyric acid only led to upregulation of MCT4 while both conditions increased transepithelial transport of ferulic acid in the apical to basolateral, but not basolateral to apical, direction. Chronic treatment also elevated intracellular concentrations of ferulic acid, which in turn gave rise to increased concentrations of ferulic acid metabolites. Immunofluorescence staining of cells revealed uniform distribution of MCT1 protein in the cell membrane, whereas MCT4 was only detected in the lateral plasma membrane sections of Caco-2 cells. We therefore propose that MCT1 may be acting as an uptake transporter and MCT4 as an efflux system across the basolateral membrane for ferulic acid, and that this process is stimulated by butyric acid. Dietary fibre gives both short chain fatty acids and phenolic acids in the colon. Ferulic acid is partially taken into cells by the transporter MCT1. Ferulic acid is effluxed basolaterally by the transporter MCT4. Butyrate upregulates transporters of phenolic acids in a colonic model. A short chain fatty acid can regulate phenolic acid absorption.
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Affiliation(s)
- Kerstin Ziegler
- School of Food Science and Nutrition, University of Leeds, Leeds LS2 9JT, UK.
| | - Asimina Kerimi
- School of Food Science and Nutrition, University of Leeds, Leeds LS2 9JT, UK.
| | - Laure Poquet
- Nestlé Research Center, CH-1000 Lausanne, Switzerland.
| | - Gary Williamson
- School of Food Science and Nutrition, University of Leeds, Leeds LS2 9JT, UK.
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21
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How, with whom and when: an overview of CD147-mediated regulatory networks influencing matrix metalloproteinase activity. Biosci Rep 2015; 36:e00283. [PMID: 26604323 PMCID: PMC4718507 DOI: 10.1042/bsr20150256] [Citation(s) in RCA: 83] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Accepted: 11/24/2015] [Indexed: 12/11/2022] Open
Abstract
Matrix metalloproteinases (MMPs) comprise a family of 23 zinc-dependent enzymes involved in various pathologic and physiologic processes. In cancer, MMPs contribute to processes from tumour initiation to establishment of distant metastases. Complex signalling and protein transport networks regulate MMP synthesis, cell surface presentation and release. Earlier attempts to disrupt MMP activity in patients have proven to be intolerable and with underwhelming clinical efficacy; thus targeting ancillary proteins that regulate MMP activity may be a useful therapeutic approach. Extracellular matrix metalloproteinase inducer (EMMPRIN) was originally characterized as a factor present on lung cancer cells, which stimulated collagenase (MMP-1) production in fibroblasts. Subsequent studies demonstrated that EMMPRIN was identical with several other protein factors, including basigin (Bsg), all of which are now commonly termed CD147. CD147 modulates the synthesis and activity of soluble and membrane-bound [membrane-type MMPs (MT-MMPs)] in various contexts via homophilic/heterophilic cell interactions, vesicular shedding or cell-autonomous processes. CD147 also participates in inflammation, nutrient and drug transporter activity, microbial pathology and developmental processes. Despite the hundreds of manuscripts demonstrating CD147-mediated MMP regulation, the molecular underpinnings governing this process have not been fully elucidated. The present review summarizes our present knowledge of the complex regulatory systems influencing CD147 biology and provides a framework to understand how CD147 may influence MMP activity.
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22
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de la Fuente-Ortega E, Gravotta D, Perez Bay A, Benedicto I, Carvajal-Gonzalez JM, Lehmann GL, Lagos CF, Rodríguez-Boulan E. Basolateral sorting of chloride channel 2 is mediated by interactions between a dileucine motif and the clathrin adaptor AP-1. Mol Biol Cell 2015; 26:1728-42. [PMID: 25739457 PMCID: PMC4436783 DOI: 10.1091/mbc.e15-01-0047] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2015] [Accepted: 02/25/2015] [Indexed: 01/03/2023] Open
Abstract
ClC-2 is a ubiquitous chloride channel that regulates cell volume, ion transport, and acid-base balance. Mice knocked out for ClC-2 are blind and sterile. Basolateral localization of ClC-2 in epithelia is mediated by the interaction of a dileucine motif with a highly conserved pocket in the γ1-σ1A hemicomplex of AP-1. In spite of the many key cellular functions of chloride channels, the mechanisms that mediate their subcellular localization are largely unknown. ClC-2 is a ubiquitous chloride channel usually localized to the basolateral domain of epithelia that regulates cell volume, ion transport, and acid–base balance; mice knocked out for ClC-2 are blind and sterile. Previous work suggested that CLC-2 is sorted basolaterally by TIFS812LL, a dileucine motif in CLC-2's C-terminal domain. However, our in silico modeling of ClC-2 suggested that this motif was buried within the channel's dimerization interface and identified two cytoplasmically exposed dileucine motifs, ESMI623LL and QVVA635LL, as candidate sorting signals. Alanine mutagenesis and trafficking assays support a scenario in which ESMI623LL acts as the authentic basolateral signal of ClC-2. Silencing experiments and yeast three-hybrid assays demonstrated that both ubiquitous (AP-1A) and epithelium-specific (AP-1B) forms of the tetrameric clathrin adaptor AP-1 are capable of carrying out basolateral sorting of ClC-2 through interactions of ESMI623LL with a highly conserved pocket in their γ1-σ1A hemicomplex.
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Affiliation(s)
- Erwin de la Fuente-Ortega
- Dyson Vision Research Institute, Department of Ophthalmology, Weill Cornell Medical College, New York, NY 10065
| | - Diego Gravotta
- Dyson Vision Research Institute, Department of Ophthalmology, Weill Cornell Medical College, New York, NY 10065
| | - Andres Perez Bay
- Dyson Vision Research Institute, Department of Ophthalmology, Weill Cornell Medical College, New York, NY 10065
| | - Ignacio Benedicto
- Dyson Vision Research Institute, Department of Ophthalmology, Weill Cornell Medical College, New York, NY 10065
| | | | - Guillermo L Lehmann
- Dyson Vision Research Institute, Department of Ophthalmology, Weill Cornell Medical College, New York, NY 10065
| | - Carlos F Lagos
- Department of Endocrinology, School of Medicine, Pontificia Universidad Católica de Chile, Santiago Centro 8330074, Santiago, Chile Facultad de Ciencia, Universidad San Sebastián, Providencia 7510157, Santiago, Chile
| | - Enrique Rodríguez-Boulan
- Dyson Vision Research Institute, Department of Ophthalmology, Weill Cornell Medical College, New York, NY 10065
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Bergersen LH. Lactate transport and signaling in the brain: potential therapeutic targets and roles in body-brain interaction. J Cereb Blood Flow Metab 2015; 35:176-85. [PMID: 25425080 PMCID: PMC4426752 DOI: 10.1038/jcbfm.2014.206] [Citation(s) in RCA: 147] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Revised: 09/30/2014] [Accepted: 10/24/2014] [Indexed: 12/26/2022]
Abstract
Lactate acts as a 'buffer' between glycolysis and oxidative metabolism. In addition to being exchanged as a fuel by the monocarboxylate transporters (MCTs) between cells and tissues with different glycolytic and oxidative rates, lactate may be a 'volume transmitter' of brain signals. According to some, lactate is a preferred fuel for brain metabolism. Immediately after brain activation, the rate of glycolysis exceeds oxidation, leading to net production of lactate. At physical rest, there is a net efflux of lactate from the brain into the blood stream. But when blood lactate levels rise, such as in physical exercise, there is net influx of lactate from blood to brain, where the lactate is used for energy production and myelin formation. Lactate binds to the lactate receptor GPR81 aka hydroxycarboxylic acid receptor (HCAR1) on brain cells and cerebral blood vessels, and regulates the levels of cAMP. The localization and function of HCAR1 and the three MCTs (MCT1, MCT2, and MCT4) expressed in brain constitute the focus of this review. They are possible targets for new therapeutic drugs and interventions. The author proposes that lactate actions in the brain through MCTs and the lactate receptor underlie part of the favorable effects on the brain resulting from physical exercise.
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Affiliation(s)
- Linda Hildegard Bergersen
- 1] The Brain and Muscle Energy Group, SN-Lab, Department of Anatomy, Institute of Basic Medical Sciences, Healthy Brain Ageing Centre, University of Oslo, Oslo, Norway [2] Department of Neuroscience and Pharmacology, University of Copenhagen, Copenhagen, Denmark [3] Center for Healthy Aging, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark [4] The Brain and Muscle Energy Group, Department of Oral Biology, University of Oslo, Oslo, Norway
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Lehmann GL, Benedicto I, Philp NJ, Rodriguez-Boulan E. Plasma membrane protein polarity and trafficking in RPE cells: past, present and future. Exp Eye Res 2014; 126:5-15. [PMID: 25152359 DOI: 10.1016/j.exer.2014.04.021] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Revised: 04/15/2014] [Accepted: 04/24/2014] [Indexed: 10/24/2022]
Abstract
The retinal pigment epithelium (RPE) comprises a monolayer of polarized pigmented epithelial cells that is strategically interposed between the neural retina and the fenestrated choroid capillaries. The RPE performs a variety of vectorial transport functions (water, ions, metabolites, nutrients and waste products) that regulate the composition of the subretinal space and support the functions of photoreceptors (PRs) and other cells in the neural retina. To this end, RPE cells display a polarized distribution of channels, transporters and receptors in their plasma membrane (PM) that is remarkably different from that found in conventional extra-ocular epithelia, e.g. intestine, kidney, and gall bladder. This characteristic PM protein polarity of RPE cells depends on the interplay of sorting signals in the RPE PM proteins and sorting mechanisms and biosynthetic/recycling trafficking routes in the RPE cell. Although considerable progress has been made in our understanding of the RPE trafficking machinery, most available data have been obtained from immortalized RPE cell lines that only partially maintain the RPE phenotype and by extrapolation of data obtained in the prototype Madin-Darby Canine Kidney (MDCK) cell line. The increasing availability of RPE cell cultures that more closely resemble the RPE in vivo together with the advent of advanced live imaging microscopy techniques provides a platform and an opportunity to rapidly expand our understanding of how polarized protein trafficking contributes to RPE PM polarity.
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Affiliation(s)
- Guillermo L Lehmann
- Margaret Dyson Vision Research Institute, Department of Ophthalmology, Weill Cornell Medical College, 1300 York Ave, New York, NY 100652, USA
| | - Ignacio Benedicto
- Margaret Dyson Vision Research Institute, Department of Ophthalmology, Weill Cornell Medical College, 1300 York Ave, New York, NY 100652, USA
| | - Nancy J Philp
- Thomas Jefferson University, Department of Pathology, Anatomy, and Cell Biology, Philadelphia, PA 19107, USA.
| | - Enrique Rodriguez-Boulan
- Margaret Dyson Vision Research Institute, Department of Ophthalmology, Weill Cornell Medical College, 1300 York Ave, New York, NY 100652, USA.
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Pinheiro C, Penna V, Morais-Santos F, Abrahão-Machado LF, Ribeiro G, Curcelli EC, Olivieri MV, Morini S, Valença I, Ribeiro D, Schmitt FC, Reis RM, Baltazar F. Characterization of monocarboxylate transporters (MCTs) expression in soft tissue sarcomas: distinct prognostic impact of MCT1 sub-cellular localization. J Transl Med 2014; 12:118. [PMID: 24885736 PMCID: PMC4036386 DOI: 10.1186/1479-5876-12-118] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2013] [Accepted: 04/28/2014] [Indexed: 12/03/2022] Open
Abstract
Background Soft tissue sarcomas (STSs) are a group of neoplasms, which, despite current therapeutic advances, still confer a poor outcome to half of the patients. As other solid tumors, STSs exhibit high glucose consumption rates, associated with worse prognosis and therapeutic response. As highly glycolytic tumors, we hypothesized that sarcomas should present an increased expression of lactate transporters (MCTs). Methods Immunohistochemical expression of MCT1, MCT2, MCT4 and CD147 was assessed in a series of 86 STSs and the expression profiles were associated with patients’ clinical-pathological parameters. Results MCT1, MCT4 and CD147 were mainly observed in the plasma membrane of cancer cells (around 60% for MCTs and 40% for CD147), while MCT2 was conspicuously found in the cytoplasm (94.2%). Importantly, we observed MCT1 nuclear expression (32.6%). MCT1 and MCT4, alone or co-expressed with CD147 in the plasma membrane, were associated with poor prognostic variables including high tumor grade, disease progression and shorter overall survival. Conversely, we found MCT1 nuclear expression to be associated with low grade tumors and longer overall survival. Conclusions The present work represents the first report of MCTs characterization in STSs. We showed the original finding of MCT1 expression in the nucleus. Importantly, opposite biological roles should be behind the dual sub-cellular localization of MCT1, as plasma membrane expression of MCT1 is associated with worse patients’ prognosis, while nuclear expression is associated with better prognosis.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | - Fátima Baltazar
- Life and Health Sciences Research Institute, School of Health Sciences, University of Minho, 4710-057 Braga, Portugal.
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Uhernik AL, Li L, LaVoy N, Velasquez MJ, Smith JP. Regulation of monocarboxylic acid transporter-1 by cAMP dependent vesicular trafficking in brain microvascular endothelial cells. PLoS One 2014; 9:e85957. [PMID: 24454947 PMCID: PMC3894203 DOI: 10.1371/journal.pone.0085957] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2013] [Accepted: 12/03/2013] [Indexed: 01/23/2023] Open
Abstract
In this study, a detailed characterization of Monocarboxylic Acid Transporter-1 (Mct1) in cytoplasmic vesicles of cultured rat brain microvascular endothelial cells shows them to be a diverse population of endosomes intrinsic to the regulation of the transporter by a brief 25 to 30 minute exposure to the membrane permeant cAMP analog, 8Br-cAMP. The vesicles are heterogeneous in size, mobility, internal pH, and co-localize with discreet markers of particular types of endosomes including early endosomes, clathrin coated vesicles, caveolar vesicles, trans-golgi, and lysosomes. The vesicular localization of Mct1 was not dependent on its N or C termini, however, the size and pH of Mct1 vesicles was increased by deletion of either terminus demonstrating a role for the termini in vesicular trafficking of Mct1. Using a novel BCECF-AM based assay developed in this study, 8Br-cAMP was shown to decrease the pH of Mct1 vesicles after 25 minutes. This result and method were confirmed in experiments with a ratiometric pH-sensitive EGFP-mCherry dual tagged Mct1 construct. Overall, the results indicate that cAMP signaling reduces the functionality of Mct1 in cerebrovascular endothelial cells by facilitating its entry into a highly dynamic vesicular trafficking pathway that appears to lead to the transporter's trafficking to autophagosomes and lysosomes.
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Affiliation(s)
- Amy L. Uhernik
- Department of Biology, Colorado State University-Pueblo, Pueblo, Colorado, United States of America
| | - Lun Li
- Department of Biology, Colorado State University-Pueblo, Pueblo, Colorado, United States of America
| | - Nathan LaVoy
- Department of Biology, Colorado State University-Pueblo, Pueblo, Colorado, United States of America
| | - Micah J. Velasquez
- Department of Biology, Colorado State University-Pueblo, Pueblo, Colorado, United States of America
| | - Jeffrey P. Smith
- Department of Biology, Colorado State University-Pueblo, Pueblo, Colorado, United States of America
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28
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Halestrap AP. The SLC16 gene family – Structure, role and regulation in health and disease. Mol Aspects Med 2013; 34:337-49. [DOI: 10.1016/j.mam.2012.05.003] [Citation(s) in RCA: 403] [Impact Index Per Article: 36.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2012] [Accepted: 03/08/2012] [Indexed: 11/29/2022]
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30
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Smith JP, Uhernik AL, Li L, Liu Z, Drewes LR. Regulation of Mct1 by cAMP-dependent internalization in rat brain endothelial cells. Brain Res 2012; 1480:1-11. [PMID: 22925948 DOI: 10.1016/j.brainres.2012.08.026] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2012] [Revised: 08/08/2012] [Accepted: 08/15/2012] [Indexed: 10/28/2022]
Abstract
In the cerebrovascular endothelium, monocarboxylic acid transporter 1 (Mct1) controls blood-brain transport of short chain monocarboxylic and keto acids, including pyruvate and lactate, to support brain energy metabolism. Mct1 function is acutely decreased in rat brain cerebrovascular endothelial cells by β-adrenergic signaling through cyclic adenosine monophosphate (cAMP); however, the mechanism for this acute reduction in transport capacity is unknown. In this report, we demonstrate that cAMP induces the dephosphorylation and internalization of Mct1 from the plasma membrane into caveolae and early endosomes in the RBE4 rat brain cerebrovascular endothelial cell line. Additionally, we provide evidence that Mct1 constitutively cycles through clathrin vesicles and recycling endosomes in a pathway that is not dependent upon cAMP signaling in these cells. Our results are important because they show for the first time the regulated and unregulated vesicular trafficking of Mct1 in cerebrovascular endothelial cells; processes which have significance for better understanding normal brain energy metabolism, and the etiology and potential therapeutic approaches to treating brain diseases, such as stroke, in which lactic acidosis is a key component.
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Affiliation(s)
- Jeffrey P Smith
- Colorado State University-Pueblo, Department of Biology, 2200 Bonforte Blvd., Pueblo, CO 81001, USA.
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31
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Abstract
The polarized distribution of proteins and lipids at the surface membrane of epithelial cells results in the formation of an apical and a basolateral domain, which are separated by tight junctions. The generation and maintenance of epithelial polarity require elaborate mechanisms that guarantee correct sorting and vectorial delivery of cargo molecules. This dynamic process involves the interaction of sorting signals with sorting machineries and the formation of transport carriers. Here we review the recent advances in the field of polarized sorting in epithelial cells. We especially highlight the role of lipid rafts in apical sorting.
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32
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Nguyen TT, Bonanno JA. Lactate-H⁺ transport is a significant component of the in vivo corneal endothelial pump. Invest Ophthalmol Vis Sci 2012; 53:2020-9. [PMID: 22410572 DOI: 10.1167/iovs.12-9475] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
PURPOSE To confirm the expression of monocarboxylate transporters (MCT) 1, 2, and 4 in rabbit CE and to test the hypothesis that cellular buffering contributed by HCO₃⁻, NBCe1, and carbonic anhydrase (CA) activity facilitates lactate-H⁺ efflux thereby controlling corneal hydration in vivo. METHODS MCT1-4 expression of rabbit endothelium was examined by Western blotting and immunofluorescence staining. Lactate-induced acidification (LIA) was measured in perfused CE in the presence and absence of HCO₃⁻ and acetazolamide (ACTZ) using tissue treated with siRNA specific to MCT1, 2, and 4. Corneal thickness and lactate concentration were measured in New Zealand White rabbits treated with the topical CA inhibitor Azopt, and from eyes that were injected intracamerally with ouabain, disodium 4,4'-diisothiocyanatostilbene-2,2'-disulfonate (DIDS), and shRNA specific to the 1Na⁺:2HCO₃⁻ cotransporter NBCe1. RESULTS MCT1 and MCT4 are localized to the lateral membrane, while MCT2 is apical. Cell pH measurements showed LIA in response to 40 mM lactate in bicarbonate free (BF) Ringer's that was inhibited by niflumic acid and by MCT siRNA knockdown, and significantly reduced in the presence of HCO₃⁻. Lactate-dependent proton flux in vitro was not significantly greater in the presence of HCO₃⁻ or reduced by ACTZ. However, when active transport, NBCe1, or CA activity was disrupted in vivo, corneal edema ensued and was associated with significant corneal lactate accumulation. CONCLUSIONS MCT1, 2, and 4 are expressed in rabbit CE on both the apical and basolateral surfaces and function to transport lactate-H⁺. Lactate-H⁺ flux is facilitated by active transport, HCO₃⁻ transport and CA activity, disruption of which causes corneal edema in vivo and indicates that facilitation of lactate efflux is a component of the endothelial pump.
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Affiliation(s)
- Tracy T Nguyen
- Indiana University School of Optometry, Bloomington, Indiana 47405, USA
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Carvajal-Gonzalez JM, Gravotta D, Mattera R, Diaz F, Perez Bay A, Roman AC, Schreiner RP, Thuenauer R, Bonifacino JS, Rodriguez-Boulan E. Basolateral sorting of the coxsackie and adenovirus receptor through interaction of a canonical YXXPhi motif with the clathrin adaptors AP-1A and AP-1B. Proc Natl Acad Sci U S A 2012; 109:3820-5. [PMID: 22343291 PMCID: PMC3309744 DOI: 10.1073/pnas.1117949109] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
The coxsackie and adenovirus receptor (CAR) plays key roles in epithelial barrier function at the tight junction, a localization guided in part by a tyrosine-based basolateral sorting signal, (318)YNQV(321). Sorting motifs of this type are known to route surface receptors into clathrin-mediated endocytosis through interaction with the medium subunit (μ2) of the clathrin adaptor AP-2, but how they guide new and recycling membrane proteins basolaterally is unknown. Here, we show that YNQV functions as a canonical YxxΦ motif, with both Y318 and V321 required for the correct basolateral localization and biosynthetic sorting of CAR, and for interaction with a highly conserved pocket in the medium subunits (μ1A and μ1B) of the clathrin adaptors AP-1A and AP-1B. Knock-down experiments demonstrate that AP-1A plays a role in the biosynthetic sorting of CAR, complementary to the role of AP-1B in basolateral recycling of this receptor. Our study illustrates how two clathrin adaptors direct basolateral trafficking of a plasma membrane protein through interaction with a canonical YxxΦ motif.
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Affiliation(s)
- Jose Maria Carvajal-Gonzalez
- Department of Ophthalmology, Department of Cell and Developmental Biology, Department of Physiology and Biophysics, Margaret Dyson Vision Research Institute, Weill Cornell Medical College, New York, NY 10065
| | - Diego Gravotta
- Department of Ophthalmology, Department of Cell and Developmental Biology, Department of Physiology and Biophysics, Margaret Dyson Vision Research Institute, Weill Cornell Medical College, New York, NY 10065
| | - Rafael Mattera
- Cell Biology and Metabolism Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892
| | - Fernando Diaz
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA 02115
| | - Andres Perez Bay
- Department of Ophthalmology, Department of Cell and Developmental Biology, Department of Physiology and Biophysics, Margaret Dyson Vision Research Institute, Weill Cornell Medical College, New York, NY 10065
| | - Angel C. Roman
- Instituto Cajal–Consejo Superior de Investigaciones Cientificas, 28002 Madrid, Spain; and
| | - Ryan P. Schreiner
- Department of Ophthalmology, Department of Cell and Developmental Biology, Department of Physiology and Biophysics, Margaret Dyson Vision Research Institute, Weill Cornell Medical College, New York, NY 10065
| | | | - Juan S. Bonifacino
- Cell Biology and Metabolism Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892
| | - Enrique Rodriguez-Boulan
- Department of Ophthalmology, Department of Cell and Developmental Biology, Department of Physiology and Biophysics, Margaret Dyson Vision Research Institute, Weill Cornell Medical College, New York, NY 10065
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Cereijido M, Contreras RG, Shoshani L, Larre I. The Na+-K+-ATPase as self-adhesion molecule and hormone receptor. Am J Physiol Cell Physiol 2011; 302:C473-81. [PMID: 22049208 DOI: 10.1152/ajpcell.00083.2011] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Thanks to the homeostasis of the internal milieu, metazoan cells can enormously simplify their housekeeping efforts and engage instead in differentiation and multiple forms of organization (tissues, organs, systems) that enable them to produce an astonishing diversity of mammals. The stability of the internal milieu despite drastic variations of the external environment (air, fresh or seawater, gastrointestinal fluids, glomerular filtrate, bile) is due to transporting epithelia that can adjust their specific permeability to H(2)O, H(+), Na(+), K(+), Ca(2+), and Cl(-) over several orders of magnitude and exchange substances with the outer milieu with exquisite precision. This exchange is due to the polarized expression of membrane proteins, among them Na(+)-K(+)-ATPase, an oligomeric enzyme that uses chemical energy from ATP molecules to translocate ions across the plasma membrane of epithelial cells. Na(+)-K(+)-ATPase presents two types of asymmetries: the arrangement of its subunits, and its expression in one pole of the epithelial cell ("polarity"). In most epithelia, polarity consists of the expression of Na(+)-K(+)-ATPase towards the intercellular space and arises in part from the interaction of the extracellular segment of the β-subunit with another β-subunit present in a Na(+)-K(+)-ATPase molecule expressed by a neighboring cell. In addition to enabling the Na(+)-K(+)-ATPase to transport ions and water vectorially, this position exposes its receptors to ouabain and analogous cardiotonic steroids, which are present in the internal milieu because these were secreted by endocrine cells.
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Affiliation(s)
- M Cereijido
- CINVESTAV, Col. San Pedro Zacatenco, Del. Gustavo A. Madero, México, D.F., México.
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Gephart JD, Singh B, Higginbotham JN, Franklin JL, Gonzalez A, Fölsch H, Coffey RJ. Identification of a novel mono-leucine basolateral sorting motif within the cytoplasmic domain of amphiregulin. Traffic 2011; 12:1793-804. [PMID: 21917092 DOI: 10.1111/j.1600-0854.2011.01282.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Epithelial cells establish apical and basolateral (BL) membranes with distinct protein and lipid compositions. To achieve this spatial asymmetry, the cell utilizes a variety of mechanisms for differential sorting, delivery and retention of cell surface proteins. The EGF receptor (EGFR) and its ligand, amphiregulin (AREG), are transmembrane proteins delivered to the BL membrane in polarized epithelial cells. Herein, we show that the cytoplasmic domain of AREG (ACD) contains dominant BL sorting information; replacement of the cytoplasmic domain of apically targeted nerve growth factor receptor with the ACD redirects the chimera to the BL surface. Using sequential truncations and site-directed mutagenesis of the ACD, we identify a novel BL sorting motif consisting of a single leucine C-terminal to an acidic cluster (EEXXXL). In adaptor protein (AP)-1B-deficient cells, newly synthesized AREG is initially delivered to the BL surface as in AP-1B-expressing cells. However, in these AP-1B-deficient cells, recycling of AREG back to the BL surface is compromised, leading to its appearance at the apical surface. These results show that recycling, but not delivery, of AREG to the BL surface is AP-1B dependent.
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Affiliation(s)
- Jonathan D Gephart
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37232, USA
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Castorino JJ, Gallagher-Colombo SM, Levin AV, Fitzgerald PG, Polishook J, Kloeckener-Gruissem B, Ostertag E, Philp NJ. Juvenile cataract-associated mutation of solute carrier SLC16A12 impairs trafficking of the protein to the plasma membrane. Invest Ophthalmol Vis Sci 2011; 52:6774-84. [PMID: 21778275 DOI: 10.1167/iovs.10-6579] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE SLC16A12 encodes an orphan member of the monocarboxylate transporter family, MCT12. A nonsense mutation in SLC16A12 (c.643C>T; p.Q215X) causes juvenile cataract with a dominant inheritance pattern. In the present study, in vitro and in vivo experimental models were used to gain insight into how the SLC16A12 (c.643C>T) mutation leads to cataract formation. METHODS MCT12 peptide antibodies were generated and used to examine the expression of MCT12 in the lens using immuno-confocal microscopy. To determine whether loss of Slc16a12 resulted in cataract formation, a Slc16a12 hypomorphic rat generated by transposon insertional mutagenesis was characterized using RT-PCR, slit lamp microscopy and histologic methods. Exogenous expression of MCT12 and MCT12:214Δ, a mimic of the mutant allele, were used to assess protein expression and trafficking. RESULTS MCT12 protein was detected in the lens epithelium and secondary fiber cells at postnatal day 1. In the Slc16a12(TKO) rat, complete loss of MCT12 did not result in any detectable ocular phenotype. Exogenous expression of MCT12-GFP and MCT12:214Δ-GFP revealed that the full-length protein was trafficked to the plasma membrane (PM), whereas the truncated protein was retained in the endoplasmic reticulum (ER). When both MCT12 and MCT12:214Δ were coexpressed, to mimic the heterozygous patient genotype, the truncated protein was retained in the ER whereas full-length MCT12 was trafficked to the PM. Furthermore, MCT12 was identified as another MCT isoform that requires CD147 for trafficking to the cell surface. CONCLUSIONS These data support a model whereby the SLC16A12 (c.643C>T) mutation causes juvenile cataract by a defect in protein trafficking rather than by haploinsufficiency.
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Affiliation(s)
- John J Castorino
- Department of Pathology, Anatomy, and Cell Biology, Jefferson Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA
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