1
|
Peña-Münzenmayer G, George AT, Llontop N, Mazola Y, Apablaza N, Spichiger C, Brauchi S, Sarmiento J, Zúñiga L, González W, Catalán MA. K +-Driven Cl -/HCO 3- Exchange Mediated by Slc4a8 and Slc4a10. Int J Mol Sci 2024; 25:4575. [PMID: 38674160 PMCID: PMC11050268 DOI: 10.3390/ijms25084575] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2024] [Revised: 04/11/2024] [Accepted: 04/12/2024] [Indexed: 04/28/2024] Open
Abstract
Slc4a genes encode various types of transporters, including Na+-HCO3- cotransporters, Cl-/HCO3- exchangers, or Na+-driven Cl-/HCO3- exchangers. Previous research has revealed that Slc4a9 (Ae4) functions as a Cl-/HCO3- exchanger, which can be driven by either Na+ or K+, prompting investigation into whether other Slc4a members facilitate cation-dependent anion transport. In the present study, we show that either Na+ or K+ drive Cl-/HCO3- exchanger activity in cells overexpressing Slc4a8 or Slc4a10. Further characterization of cation-driven Cl-/HCO3- exchange demonstrated that Slc4a8 and Slc4a10 also mediate Cl- and HCO3--dependent K+ transport. Full-atom molecular dynamics simulation on the recently solved structure of Slc4a8 supports the coordination of K+ at the Na+ binding site in S1. Sequence analysis shows that the critical residues coordinating monovalent cations are conserved among mouse Slc4a8 and Slc4a10 proteins. Together, our results suggest that Slc4a8 and Slc4a10 might transport K+ in the same direction as HCO3- ions in a similar fashion to that described for Na+ transport in the rat Slc4a8 structure.
Collapse
Affiliation(s)
- Gaspar Peña-Münzenmayer
- Instituto de Bioquímica y Microbiología, Facultad de Ciencias, Universidad Austral de Chile, Valdivia 5090000, Chile; (G.P.-M.); (N.A.); (C.S.)
- Millennium Nucleus of Ion Channels-Associated Diseases (MiNICAD), Valdivia 5090000, Chile
| | - Alvin T. George
- Secretory Mechanisms and Dysfunction Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD 20892, USA
| | - Nuria Llontop
- Instituto de Fisiología, Facultad de Medicina, Universidad Austral de Chile, Valdivia 5090000, Chile; (N.L.); (J.S.)
| | - Yuliet Mazola
- Center for Bioinformatics and Molecular Simulations (CBSM), Universidad de Talca, Talca 3460000, Chile (W.G.)
| | - Natalia Apablaza
- Instituto de Bioquímica y Microbiología, Facultad de Ciencias, Universidad Austral de Chile, Valdivia 5090000, Chile; (G.P.-M.); (N.A.); (C.S.)
| | - Carlos Spichiger
- Instituto de Bioquímica y Microbiología, Facultad de Ciencias, Universidad Austral de Chile, Valdivia 5090000, Chile; (G.P.-M.); (N.A.); (C.S.)
| | - Sebastián Brauchi
- Millennium Nucleus of Ion Channels-Associated Diseases (MiNICAD), Valdivia 5090000, Chile
- Instituto de Fisiología, Facultad de Medicina, Universidad Austral de Chile, Valdivia 5090000, Chile; (N.L.); (J.S.)
| | - José Sarmiento
- Instituto de Fisiología, Facultad de Medicina, Universidad Austral de Chile, Valdivia 5090000, Chile; (N.L.); (J.S.)
| | - Leandro Zúñiga
- Centro de Nanomedicina, Diagnóstico y Desarrollo de Fármacos (ND3), Laboratorio de Fisiología Molecular, Escuela de Medicina, Universidad de Talca, Casilla, Talca 3460000, Chile;
| | - Wendy González
- Center for Bioinformatics and Molecular Simulations (CBSM), Universidad de Talca, Talca 3460000, Chile (W.G.)
- Millennium Nucleus of Ion Channels-Associated Diseases (MiNICAD), Talca 3460000, Chile
| | - Marcelo A. Catalán
- Instituto de Fisiología, Facultad de Medicina, Universidad Austral de Chile, Valdivia 5090000, Chile; (N.L.); (J.S.)
| |
Collapse
|
2
|
Palacios J, Asunción-Alvarez D, Aravena D, Chiong M, Catalán MA, Parra C, Cifuentes F, Paredes A. A new oxime synthesized from Senecio nutans SCh. Bip (chachacoma) reduces calcium influx in the vascular contractile response in rat aorta. RSC Adv 2024; 14:9933-9942. [PMID: 38528924 PMCID: PMC10962255 DOI: 10.1039/d4ra01058b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2024] [Accepted: 03/13/2024] [Indexed: 03/27/2024] Open
Abstract
Senecio nutans Sch. Bip is an endemic plant commonly employed in the Andes culture to counteract the effects of mountain sickness, and its bioactive molecules could provide new drugs for treating hypertension. The purpose was to determine whether the vascular response of the plant bioactive molecules, such as (5-acetyl-6-hydroxy-2-isopropenyl-2,3-dihydrobenzofurane; Sn-I), could be improved by a simple structural modification to synthesize oximes (Ox-Sn-I). We characterized both compounds using IR and NMR spectroscopy and Heteronuclear Multiple Quantum Coherence (HMQC). We investigated vascular relaxation mechanisms in response to Sn-I and Ox-Sn-I using rat aorta and vascular smooth muscle cells (A7r5) as experimental models. Preincubation of aortic rings with Sn-I (10-5 M) significantly (p < 0.001) decreased the contractile effect in response to phenylephrine (PE) and potassium chloride (KCl). The sensitivity (EC50) to PE significantly (p < 0.01) decreased in the presence of Sn-I (10-5 M), but not with Ox-Sn-I. Sn-I significantly (p < 0.001) reduced the PE-induced contraction under calcium-free conditions. When A7r5 cells were preincubated with Sn-I and Ox-Sn-I (10-5 M), both compounds blunted the increase in intracellular Ca2+ induced by KCl. 2,3-Dihydrobenzofurane derived from S. nutans (Sn-I) reduces the contractile response probably by blocking Ca2+ entry through voltage-gated Ca2+ channels (VGCC) in vascular smooth cells. This effect also causes relaxation in rat aorta mediated by reduction of intracellular Ca2+ concentration, rather than an increase of NO generation in endothelial vascular cells.
Collapse
Affiliation(s)
- Javier Palacios
- Laboratorio de Bioquímica Aplicada, Facultad de Ciencias de la Salud, Universidad Arturo Prat Iquique 1110939 Chile
| | - Daniel Asunción-Alvarez
- Laboratorio de Bioquímica Aplicada, Facultad de Ciencias de la Salud, Universidad Arturo Prat Iquique 1110939 Chile
| | - Diego Aravena
- Laboratorio de Bioquímica Aplicada, Facultad de Ciencias de la Salud, Universidad Arturo Prat Iquique 1110939 Chile
| | - Mario Chiong
- Universidad de Chile, Advanced Center for Chronic Diseases (ACCDiS), Facultad de Ciencias Químicas y Farmacéuticas Santiago Chile
| | - Marcelo A Catalán
- Instituto de Fisiología, Facultad de Medicina, Universidad Austral de Chile Valdivia 5090000 Chile
| | - Claudio Parra
- Departamento de Química Orgánica, Facultad de Ciencias Químicas, Universidad de Concepción Edmundo Larenas 129 Concepción 4070371 Chile
| | - Fredi Cifuentes
- Laboratorio de Fisiología Experimental (EPhyL), Instituto Antofagasta (IA), Universidad de Antofagasta Antofagasta 1271155 Chile
| | - Adrián Paredes
- Departamento de Química, Facultad de Ciencias Básicas, Universidad de Antofagasta Antofagasta 1271155 Chile
| |
Collapse
|
3
|
Muñoz M, Acevedo A, Ovitt CE, Luitje ME, Maruyama EO, Catalán MA. CFTR expression in human salivary gland acinar cells. Am J Physiol Cell Physiol 2024; 326:C742-C748. [PMID: 38284125 DOI: 10.1152/ajpcell.00549.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Revised: 01/08/2024] [Accepted: 01/20/2024] [Indexed: 01/30/2024]
Abstract
The key role of CFTR in secretory epithelia has been extensively documented. Additionally, CFTR plays a significant role in ion absorption in exocrine glands, including salivary and sweat glands. Most of the knowledge about CFTR expression comes from animal models such as the mouse or the rat, but there is limited information about CFTR expression in human tissues. In the present study, we assessed the expression of CFTR in human submandibular and parotid glands. Consistent with findings in rodent salivary glands, our immunolocalization studies show that CFTR is expressed in duct cells. However, CFTR expression in human salivary glands differs from that in rodents, as immunolocalization and single-cell RNA sequencing analysis from a previous study performed in the human parotid gland revealed the presence of CFTR protein and transcripts within a distinct cell cluster. Based on cell marker expression, this cluster corresponds to acinar cells. To obtain functional evidence supporting CFTR expression, we isolated human parotid acinar cells through collagenase digestion. Acinar cells displayed an anion conductance that was activated in response to cAMP-increasing agents and was effectively blocked by CFTRInh172, a known CFTR blocker. This study provides novel evidence of CFTR expression within acinar cells of human salivary glands. This finding challenges the established model positioning CFTR exclusively in duct cells from exocrine glands.NEW & NOTEWORTHY This study addresses the uncertainty about the impact of CFTR on human salivary gland function. We found CFTR transcripts in a subset of duct cells known as ionocytes, as well as in acinar cells. Isolated human parotid acinar cells exhibited Cl- conductance consistent with CFTR activity. This marks the first documented evidence of functional CFTR expression in human salivary gland acinar cells.
Collapse
Affiliation(s)
- Manuel Muñoz
- Instituto de Nutrición y Tecnología de los Alimentos, Universidad de Chile, Santiago, Chile
| | - Alejandro Acevedo
- Instituto de Nutrición y Tecnología de los Alimentos, Universidad de Chile, Santiago, Chile
| | - Catherine E Ovitt
- Department of Biomedical Genetics, University of Rochester Medical Center, Rochester, New York, United States
| | - Martha E Luitje
- Department of Otolaryngology, University of Rochester Medical Center, Rochester, New York, United States
| | - Eri O Maruyama
- Department of Biomedical Genetics, University of Rochester Medical Center, Rochester, New York, United States
| | - Marcelo A Catalán
- Instituto de Fisiología, Facultad de Medicina, Universidad Austral de Chile, Valdivia, Chile
| |
Collapse
|
4
|
Ybañez-Julca RO, Pino-Ríos R, Quispe-Díaz IM, Asunción-Alvarez D, Acuña-Tarrillo EE, Mantilla-Rodríguez E, Minchan-Herrera P, Catalán MA, Zevallos-Escobar L, Vásquez-Corales E, Yáñez O, Gutiérrez-Alvarado WO, Benites J. Antispasmodic Effect of Valeriana pilosa Root Essential Oil and Potential Mechanisms of Action: Ex Vivo and In Silico Studies. Pharmaceutics 2023; 15:2072. [PMID: 37631286 PMCID: PMC10458982 DOI: 10.3390/pharmaceutics15082072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Revised: 07/28/2023] [Accepted: 07/30/2023] [Indexed: 08/27/2023] Open
Abstract
Infusions of Valeriana pilosa are commonly used in Peruvian folk medicine for treating gastrointestinal disorders. This study aimed to investigate the spasmolytic and antispasmodic effects of Valeriana pilosa essential oil (VPEO) on rat ileum. The basal tone of ileal sections decreased in response to accumulative concentrations of VPEO. Moreover, ileal sections precontracted with acetylcholine (ACh), potassium chloride (KCl), or barium chloride (BaCl2) were relaxed in response to VPEO by a mechanism that depended on atropine, hyoscine butylbromide, solifenacin, and verapamil, but not glibenclamide. The results showed that VPEO produced a relaxant effect by inhibiting muscarinic receptors and blocking calcium channels, with no apparent effect on the opening of potassium channels. In addition, molecular docking was employed to evaluate VPEO constituents that could inhibit intestinal contractile activity. The study showed that α-cubebene, β-patchoulene, β-bourbonene, β-caryophyllene, α-guaiene, γ-muurolene, valencene, eremophyllene, and δ-cadinene displayed the highest docking scores on muscarinic acetylcholine receptors and voltage-gated calcium channels, which may antagonize M2 and/or M3 muscarinic acetylcholine receptors and block voltage-gated calcium channels. In summary, VPEO has both spasmolytic and antispasmodic effects. It may block muscarinic receptors and calcium channels, thus providing a scientific basis for its traditional use for gastrointestinal disorders.
Collapse
Affiliation(s)
- Roberto O. Ybañez-Julca
- Facultad de Farmacia y Bioquímica, Universidad Nacional de Trujillo, Trujillo 13011, Peru; (I.M.Q.-D.); (D.A.-A.); (E.E.A.-T.); (E.M.-R.); (P.M.-H.)
| | - Ricardo Pino-Ríos
- Química y Farmacia, Facultad de Ciencias de la Salud, Universidad Arturo Prat, Casilla 121, Iquique 1100000, Chile;
- Instituto de Estudios de la Salud, Universidad Arturo Prat, Casilla 121, Iquique 1100000, Chile
| | - Iván M. Quispe-Díaz
- Facultad de Farmacia y Bioquímica, Universidad Nacional de Trujillo, Trujillo 13011, Peru; (I.M.Q.-D.); (D.A.-A.); (E.E.A.-T.); (E.M.-R.); (P.M.-H.)
| | - Daniel Asunción-Alvarez
- Facultad de Farmacia y Bioquímica, Universidad Nacional de Trujillo, Trujillo 13011, Peru; (I.M.Q.-D.); (D.A.-A.); (E.E.A.-T.); (E.M.-R.); (P.M.-H.)
| | - Edwin E. Acuña-Tarrillo
- Facultad de Farmacia y Bioquímica, Universidad Nacional de Trujillo, Trujillo 13011, Peru; (I.M.Q.-D.); (D.A.-A.); (E.E.A.-T.); (E.M.-R.); (P.M.-H.)
| | - Elena Mantilla-Rodríguez
- Facultad de Farmacia y Bioquímica, Universidad Nacional de Trujillo, Trujillo 13011, Peru; (I.M.Q.-D.); (D.A.-A.); (E.E.A.-T.); (E.M.-R.); (P.M.-H.)
| | - Patricia Minchan-Herrera
- Facultad de Farmacia y Bioquímica, Universidad Nacional de Trujillo, Trujillo 13011, Peru; (I.M.Q.-D.); (D.A.-A.); (E.E.A.-T.); (E.M.-R.); (P.M.-H.)
| | - Marcelo A. Catalán
- Instituto de Fisiología, Facultad de Medicina, Universidad Austral de Chile, Valdivia 5090000, Chile;
| | - Liz Zevallos-Escobar
- Escuela de Farmacia y Bioquímica, Universidad Católica Los Ángeles de Chimbote, Chimbote 02801, Peru; (L.Z.-E.); (E.V.-C.)
| | - Edison Vásquez-Corales
- Escuela de Farmacia y Bioquímica, Universidad Católica Los Ángeles de Chimbote, Chimbote 02801, Peru; (L.Z.-E.); (E.V.-C.)
| | - Osvaldo Yáñez
- Facultad de Ingeniería y Negocios, Universidad de las Américas, Santiago 7500000, Chile;
| | | | - Julio Benites
- Química y Farmacia, Facultad de Ciencias de la Salud, Universidad Arturo Prat, Casilla 121, Iquique 1100000, Chile;
- Instituto de Estudios de la Salud, Universidad Arturo Prat, Casilla 121, Iquique 1100000, Chile
| |
Collapse
|
5
|
Palacios J, Paredes A, Cifuentes F, Catalán MA, García-Villalón AL, Borquez J, Simirgiotis MJ, Jones M, Foster A, Greensmith DJ. A hydroalcoholic extract of Senecio nutans SCh. Bip (Asteraceae); its effects on cardiac function and chemical characterization. J Ethnopharmacol 2023; 300:115747. [PMID: 36152785 DOI: 10.1016/j.jep.2022.115747] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 09/07/2022] [Accepted: 09/18/2022] [Indexed: 06/16/2023]
Abstract
ETHNOPHARMACOLOGY RELEVANCE The plant Senecio nutans SCh. Bip. is used by Andean communities to treat altitude sickness. Recent evidence suggests it may produce vasodilation and negative cardiac inotropy, though the cellular mechanisms have not been elucidated. PURPOSE To determinate the mechanisms action of S. nutans on cardiovascular function in normotensive animals. METHODS The effect of the extract on rat blood pressure was measured with a transducer in the carotid artery and intraventricular pressure by a Langendorff system. The effects on sheep ventricular intracellular calcium handling and contractility were evaluated using photometry. Ultra-high-performance liquid-chromatography with diode array detection coupled with heated electrospray-ionization quadrupole-orbitrap mass spectrometric detection (UHPLC-DAD-ESI-Q-OT-MSn) was used for extract chemical characterization. RESULTS In normotensive rats, S. nutans (10 mg/kg) reduced mean arterial pressure (MAP) by 40% (p < 0.05), causing a dose-dependent coronary artery dilation and decreased left ventricular pressure. In isolated cells, S. nutans extract (1 μg/ml) rapidly reduced the [Ca2+]i transient amplitude and sarcomere shorting by 40 and 49% (p < 0.001), respectively. The amplitude of the caffeine evoked [Ca2+]i transient was reduced by 24% (p < 0.001), indicating reduced sarcoplasmic reticulum (SR) Ca2+ content. Sodium-calcium exchanger (NCX) activity increased by 17% (p < 0.05), while sarcoendoplasmic reticulum Ca2+-ATPase (SERCA) activity was decreased by 21% (p < 0.05). LC-MS results showed the presence of vitamin C, malic acid, and several antioxidant phenolic acids reported for the first time. Dihydroeuparin and 4-hydroxy-3-(3-methylbut-2-enyl) acetophenone were abundant in the extract. CONCLUSION In normotensive animals, S. nutans partially reduces MAP by decreasing heart rate and cardiac contractility. This negative inotropy is accounted for by decreased SERCA activity and increased NCX activity which reduces SR Ca2+ content. These results highlight the plant's potential as a source of novel cardio-active phytopharmaceuticals or nutraceuticals.
Collapse
Affiliation(s)
- Javier Palacios
- Laboratorio de Bioquímica Aplicada, Química y Farmacia, Facultad de Ciencias de la Salud, Universidad Arturo Prat, Iquique, 1110939, Chile.
| | - Adrián Paredes
- Departamento de Química, Facultad de Ciencias Básicas, Universidad de Antofagasta, Antofagasta, 1271155, Chile; Instituto Antofagasta (IA), Universidad de Antofagasta, Antofagasta, 1271155, Chile.
| | - Fredi Cifuentes
- Instituto Antofagasta (IA), Universidad de Antofagasta, Antofagasta, 1271155, Chile; Departamento de Biomédico, Facultad Ciencias de la Salud, Universidad de Antofagasta, Antofagasta, 1271155, Chile.
| | - Marcelo A Catalán
- Instituto de Fisiología, Facultad de Medicina, Universidad Austral de Chile, Valdivia, 5090000, Chile.
| | | | - Jorge Borquez
- Departamento de Química, Facultad de Ciencias Básicas, Universidad de Antofagasta, Antofagasta, 1271155, Chile.
| | - Mario J Simirgiotis
- Center for Interdisciplinary Studies on the Nervous System (CISNe), Universidad Austral de Chile, Valdivia, 5090000, Chile.
| | - Matthew Jones
- Biomedical Research Centre, School of Science, Engineering and Environment, The University of Salford, Salford, United Kingdom.
| | - Amy Foster
- Biomedical Research Centre, School of Science, Engineering and Environment, The University of Salford, Salford, United Kingdom.
| | - David J Greensmith
- Biomedical Research Centre, School of Science, Engineering and Environment, The University of Salford, Salford, United Kingdom.
| |
Collapse
|
6
|
Peña-Münzenmayer G, Kondo Y, Salinas C, Sarmiento J, Brauchi S, Catalán MA. Activation of the Ae4 (Slc4a9) cation-driven Cl -/HCO 3- exchanger by the cAMP-dependent protein kinase in salivary gland acinar cells. Am J Physiol Gastrointest Liver Physiol 2021; 321:G628-G638. [PMID: 34585968 PMCID: PMC8887885 DOI: 10.1152/ajpgi.00145.2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Revised: 09/24/2021] [Accepted: 09/27/2021] [Indexed: 01/31/2023]
Abstract
Ae4 transporters are critical for Cl- uptake across the basolateral membrane of acinar cells in the submandibular gland (SMG). Although required for fluid secretion, little is known about the physiological regulation of Ae4. To investigate whether Ae4 is regulated by the cAMP-dependent signaling pathway, we measured Cl-/HCO3- exchanger activity in SMG acinar cells from Ae2-/- mice, which only express Ae4, and found that the Ae4-mediated activity was increased in response to β-adrenergic receptor stimulation. Moreover, pretreatment with H89, an inhibitor of the cAMP-activated kinase (PKA), prevented the stimulation of Ae4 exchangers. We then expressed Ae4 in CHO-K1 cells and found that the Ae4-mediated activity was increased when Ae4 is coexpressed with the catalytic subunit of PKA (PKAc), which is constitutively active. Ae4 sequence analysis showed two potential PKA phosphorylation serine residues located at the intracellular NH2-terminal domain according to a homology model of Ae4. NH2-terminal domain Ser residues were mutated to alanine (S173A and S273A, respectively), where the Cl-/HCO3- exchanger activity displayed by the mutant S173A was not activated by PKA. Conversely, S273A mutant kept the PKA dependency. Together, we conclude that Ae4 is stimulated by PKA in SMG acinar cells by a mechanism that probably depends on the phosphorylation of S173.NEW & NOTEWORTHY We found that Ae4 exchanger activity in secretory salivary gland acinar cells is increased upon β-adrenergic receptor stimulation. The activation of Ae4 was prevented by H89, a nonselective PKA inhibitor. Protein sequence analysis revealed two residues (S173 and S273) that are potential targets of cAMP-dependent protein kinase (PKA). Experiments in CHO-K1 cells expressing S173A and S273A mutants showed that S173A, but not S273A, is not activated by PKA.
Collapse
Affiliation(s)
- Gaspar Peña-Münzenmayer
- Facultad de Ciencias, Instituto de Bioquímica y Microbiología, Universidad Austral de Chile, Valdivia, Chile
- Millennium Nucleus of Ion Channel-Associated Diseases (MiNICAD), Valdivia, Chile
| | - Yusuke Kondo
- Division of Oral Reconstruction and Rehabilitation, Kyushu Dental University, Fukuoka, Japan
| | - Constanza Salinas
- Facultad de Medicina, Instituto de Fisiología, Universidad Austral de Chile, Valdivia, Chile
| | - José Sarmiento
- Facultad de Medicina, Instituto de Fisiología, Universidad Austral de Chile, Valdivia, Chile
| | - Sebastián Brauchi
- Facultad de Medicina, Instituto de Fisiología, Universidad Austral de Chile, Valdivia, Chile
- Millennium Nucleus of Ion Channel-Associated Diseases (MiNICAD), Valdivia, Chile
| | - Marcelo A Catalán
- Facultad de Ciencias de la Salud, Universidad Arturo Prat, Iquique, Chile
- Facultad de Medicina, Instituto de Fisiología, Universidad Austral de Chile, Valdivia, Chile
| |
Collapse
|
7
|
Catalán MA, Julio-Kalajzić F, Niemeyer MI, Cid LP, Sepúlveda FV. Short Chain Fatty Acids Effect on Chloride Channel ClC-2 as a Possible Mechanism for Lubiprostone Intestinal Action. Cells 2020; 9:cells9081781. [PMID: 32722648 PMCID: PMC7464869 DOI: 10.3390/cells9081781] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 07/22/2020] [Accepted: 07/23/2020] [Indexed: 01/22/2023] Open
Abstract
Lubiprostone, a 20-carbon synthetic fatty acid used for the treatment of constipation, is thought to act through an action on Cl− channel ClC-2. Short chain fatty acids (SCFAs) are produced and absorbed in the distal intestine. We explore whether SCFAs affect ClC-2, re-examine a possible direct effect of lubiprostone on ClC-2, and use mice deficient in ClC-2 to stringently address the hypothesis that the epithelial effect of lubiprostone targets this anion channel. Patch-clamp whole cell recordings of ClC-2 expressed in mammalian cells are used to assay SCFA and lubiprostone effects. Using chamber measurements of ion current in mice deficient in ClC-2 or CFTR channels served to analyze the target of lubiprostone in the distal intestinal epithelium. Intracellular SCFAs had a dual action on ClC-2, partially inhibiting conduction but, importantly, facilitating the voltage activation of ClC-2. Intra- or extracellular lubiprostone had no effect on ClC-2 currents. Lubiprostone elicited a secretory current across colonic epithelia that was increased in mice deficient in ClC-2, consistent with the channel’s proposed proabsorptive function, but absent from those deficient in CFTR. Whilst SCFAs might exert a physiological effect on ClC-2 as part of their known proabsorptive effect, ClC-2 plays no part in the lubiprostone intestinal effect that appears mediated by CFTR activation.
Collapse
Affiliation(s)
- Marcelo A. Catalán
- Centro de Estudios Científicos (CECs), Avenida Arturo Prat 514, Valdivia 5110466, Chile; (F.J.-K.); (M.I.N.); (L.P.C.)
- Instituto de Fisiología, Facultad de Medicina, Universidad Austral de Chile, Valdivia 5090000, Chile
- Correspondence: (M.A.C.); (F.V.S.); Tel.: +56-63-2221686 (M.A.C.)
| | - Francisca Julio-Kalajzić
- Centro de Estudios Científicos (CECs), Avenida Arturo Prat 514, Valdivia 5110466, Chile; (F.J.-K.); (M.I.N.); (L.P.C.)
| | - María Isabel Niemeyer
- Centro de Estudios Científicos (CECs), Avenida Arturo Prat 514, Valdivia 5110466, Chile; (F.J.-K.); (M.I.N.); (L.P.C.)
| | - Luis Pablo Cid
- Centro de Estudios Científicos (CECs), Avenida Arturo Prat 514, Valdivia 5110466, Chile; (F.J.-K.); (M.I.N.); (L.P.C.)
| | - Francisco V. Sepúlveda
- Centro de Estudios Científicos (CECs), Avenida Arturo Prat 514, Valdivia 5110466, Chile; (F.J.-K.); (M.I.N.); (L.P.C.)
- Correspondence: (M.A.C.); (F.V.S.); Tel.: +56-63-2221686 (M.A.C.)
| |
Collapse
|
8
|
Concha G, Bustos D, Zúñiga R, Catalán MA, Zúñiga L. Correction: Concha, G., et al. The Insensitivity of TASK-3 K 2P Channels to External Tetraethylammonium (TEA) Partially Depends on the Cap Structure. Int. J. Mol. Sci. 2018, 19, 2437. Int J Mol Sci 2019; 20:ijms20184651. [PMID: 31546836 PMCID: PMC6770687 DOI: 10.3390/ijms20184651] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Accepted: 09/15/2019] [Indexed: 11/17/2022] Open
Affiliation(s)
- Guierdy Concha
- Centro de Investigaciones Médicas (CIM), Programa de Investigación Asociativa en Cáncer Gástrico (PIA-CG), Escuela de Medicina, Universidad de Talca, Talca 3460000, Chile.
- Magíster en Gestión de Operaciones, Facultad de Ingeniería (Campus Los Niches), Universidad de Talca, Talca 3460000, Chile.
| | - Daniel Bustos
- Centro de Investigaciones Médicas (CIM), Programa de Investigación Asociativa en Cáncer Gástrico (PIA-CG), Escuela de Medicina, Universidad de Talca, Talca 3460000, Chile.
- CBSM y Doctorado en Ciencias, mención Modelado de Sistemas Químicos y Biológicos, Facultad de Ingeniería, Universidad de Talca, Talca 3460000, Chile.
| | - Rafael Zúñiga
- Centro de Investigaciones Médicas (CIM), Programa de Investigación Asociativa en Cáncer Gástrico (PIA-CG), Escuela de Medicina, Universidad de Talca, Talca 3460000, Chile.
| | - Marcelo A Catalán
- Laboratorio de Fisiología Epitelial, Facultad de Ciencias de la Salud, Universidad Arturo Prat, Iquique 1130000, Chile.
| | - Leandro Zúñiga
- Centro de Investigaciones Médicas (CIM), Programa de Investigación Asociativa en Cáncer Gástrico (PIA-CG), Escuela de Medicina, Universidad de Talca, Talca 3460000, Chile.
| |
Collapse
|
9
|
Concha G, Bustos D, Zúñiga R, Catalán MA, Zúñiga L. The Insensitivity of TASK-3 K₂P Channels to External Tetraethylammonium (TEA) Partially Depends on the Cap Structure. Int J Mol Sci 2018; 19:ijms19082437. [PMID: 30126179 PMCID: PMC6121469 DOI: 10.3390/ijms19082437] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Revised: 08/10/2018] [Accepted: 08/13/2018] [Indexed: 01/12/2023] Open
Abstract
Two-pore domain K⁺ channels (K₂P) display a characteristic extracellular cap structure formed by two M1-P1 linkers, the functional role of which is poorly understood. It has been proposed that the presence of the cap explains the insensitivity of K₂P channels to several K⁺ channel blockers including tetraethylammonium (TEA). We have explored this hypothesis using mutagenesis and functional analysis, followed by molecular simulations. Our results show that the deletion of the cap structure of TASK-3 (TWIK-related acid-sensitive K⁺ channel) generates a TEA-sensitive channel with an IC50 of 11.8 ± 0.4 mM. The enhanced sensitivity to TEA displayed by the cap-less channel is also explained by the presence of an extra tyrosine residue at position 99. These results were corroborated by molecular simulation analysis, which shows an increased stability in the binding of TEA to the cap-less channel when a ring of four tyrosine is present at the external entrance of the permeation pathway. Consistently, Y99A or Y205A single-residue mutants generated in a cap-less channel backbone resulted in TASK-3 channels with low affinity to external TEA.
Collapse
Affiliation(s)
- Guierdy Concha
- Centro de Investigaciones Médicas (CIM), Programa de Investigación Asociativa en Cáncer Gástrico (PIA-CG), Escuela de Medicina, Universidad de Talca, Talca 3460000, Chile.
| | - Daniel Bustos
- Centro de Investigaciones Médicas (CIM), Programa de Investigación Asociativa en Cáncer Gástrico (PIA-CG), Escuela de Medicina, Universidad de Talca, Talca 3460000, Chile.
| | - Rafael Zúñiga
- Centro de Investigaciones Médicas (CIM), Programa de Investigación Asociativa en Cáncer Gástrico (PIA-CG), Escuela de Medicina, Universidad de Talca, Talca 3460000, Chile.
| | - Marcelo A Catalán
- Laboratorio de Fisiología Epitelial, Facultad de Ciencias de la Salud, Universidad Arturo Prat, Iquique 1130000, Chile.
| | - Leandro Zúñiga
- Centro de Investigaciones Médicas (CIM), Programa de Investigación Asociativa en Cáncer Gástrico (PIA-CG), Escuela de Medicina, Universidad de Talca, Talca 3460000, Chile.
| |
Collapse
|
10
|
Catalán MA, José Viveros J, Fernandez F, Flores L, Brauchi S, Peña-Münzenmayer G. Exploring the Transport Mechanism of the Human AE4 (SLC4A9) CL-/HCO3- Exchanger. Biophys J 2018. [DOI: 10.1016/j.bpj.2017.11.1851] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
|
11
|
Vera-Sigüenza E, Catalán MA, Peña-Münzenmayer G, Melvin JE, Sneyd J. A Mathematical Model Supports a Key Role for Ae4 (Slc4a9) in Salivary Gland Secretion. Bull Math Biol 2017; 80:255-282. [PMID: 29209914 DOI: 10.1007/s11538-017-0370-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Accepted: 11/22/2017] [Indexed: 12/18/2022]
Abstract
We develop a mathematical model of a salivary gland acinar cell with the objective of investigating the role of two [Formula: see text] exchangers from the solute carrier family 4 (Slc4), Ae2 (Slc4a2) and Ae4 (Slc4a9), in fluid secretion. Water transport in this type of cell is predominantly driven by [Formula: see text] movement. Here, a basolateral [Formula: see text] adenosine triphosphatase pump (NaK-ATPase) and a [Formula: see text]-[Formula: see text]-[Formula: see text] cotransporter (Nkcc1) are primarily responsible for concentrating the intracellular space with [Formula: see text] well above its equilibrium potential. Gustatory and olfactory stimuli induce the release of [Formula: see text] ions from the internal stores of acinar cells, which triggers saliva secretion. [Formula: see text]-dependent [Formula: see text] and [Formula: see text] channels promote ion secretion into the luminal space, thus creating an osmotic gradient that promotes water movement in the secretory direction. The current model for saliva secretion proposes that [Formula: see text] anion exchangers (Ae), coupled with a basolateral [Formula: see text] ([Formula: see text]) (Nhe1) antiporter, regulate intracellular pH and act as a secondary [Formula: see text] uptake mechanism (Nauntofte in Am J Physiol Gastrointest Liver Physiol 263(6):G823-G837, 1992; Melvin et al. in Annu Rev Physiol 67:445-469, 2005. https://doi.org/10.1146/annurev.physiol.67.041703.084745 ). Recent studies demonstrated that Ae4 deficient mice exhibit an approximate [Formula: see text] decrease in gland salivation (Peña-Münzenmayer et al. in J Biol Chem 290(17):10677-10688, 2015). Surprisingly, the same study revealed that absence of Ae2 does not impair salivation, as previously suggested. These results seem to indicate that the Ae4 may be responsible for the majority of the secondary [Formula: see text] uptake and thus a key mechanism for saliva secretion. Here, by using 'in-silico' Ae2 and Ae4 knockout simulations, we produced mathematical support for such controversial findings. Our results suggest that the exchanger's cotransport of monovalent cations is likely to be important in establishing the osmotic gradient necessary for optimal transepithelial fluid movement.
Collapse
Affiliation(s)
- Elías Vera-Sigüenza
- Department of Mathematics, The University of Auckland, Level 2, Building 303, 38 Princes Street, Auckland CBD, New Zealand.
| | - Marcelo A Catalán
- Departamento de Ciencias Químicas y Farmacéuticas, Facultad de Ciencias de la Salud, Universidad Arturo Prat, Iquique, Chile
| | - Gaspar Peña-Münzenmayer
- Center for Interdisciplinary Studies on the Nervous System (CISNe) and Instituto de Fisiología, Facultad de Medicina, Universidad Austral de Chile, Valdivia, Chile
| | - James E Melvin
- Secretory Mechanisms and Dysfunction Section, Division of Intramural Research, NIDCR, National Institutes of Health, Bethesda, MD, 20892, USA
| | - James Sneyd
- Department of Mathematics, The University of Auckland, Level 2, Building 303, 38 Princes Street, Auckland CBD, New Zealand
| |
Collapse
|
12
|
Peña-Münzenmayer G, George AT, Shull GE, Melvin JE, Catalán MA. Ae4 (Slc4a9) is an electroneutral monovalent cation-dependent Cl-/HCO3- exchanger. J Gen Physiol 2017; 147:423-36. [PMID: 27114614 PMCID: PMC4845690 DOI: 10.1085/jgp.201611571] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Accepted: 04/05/2016] [Indexed: 12/31/2022] Open
Abstract
Ae4 (Slc4a9) belongs to the Slc4a family of Cl(-)/HCO3 (-) exchangers and Na(+)-HCO3 (-) cotransporters, but its ion transport cycle is poorly understood. In this study, we find that native Ae4 activity in mouse salivary gland acinar cells supports Na(+)-dependent Cl(-)/HCO3 (-) exchange that is comparable with that obtained upon heterologous expression of mouse Ae4 and human AE4 in CHO-K1 cells. Additionally, whole cell recordings and ion concentration measurements demonstrate that Na(+) is transported by Ae4 in the same direction as HCO3 (-) (and opposite to that of Cl(-)) and that ion transport is not associated with changes in membrane potential. We also find that Ae4 can mediate Na(+)-HCO3 (-) cotransport-like activity under Cl(-)-free conditions. However, whole cell recordings show that this apparent Na(+)-HCO3 (-) cotransport activity is in fact electroneutral HCO3 (-)/Na(+)-HCO3 (-) exchange. Although the Ae4 anion exchanger is thought to regulate intracellular Cl(-) concentration in exocrine gland acinar cells, our thermodynamic calculations predict that the intracellular Na(+), Cl(-), and HCO3 (-) concentrations required for Ae4-mediated Cl(-) influx differ markedly from those reported for acinar secretory cells at rest or under sustained stimulation. Given that K(+) ions share many properties with Na(+) ions and reach intracellular concentrations of 140-150 mM (essentially the same as extracellular [Na(+)]), we hypothesize that Ae4 could mediate K(+)-dependent Cl(-)/HCO3 (-) exchange. Indeed, we find that Ae4 mediates Cl(-)/HCO3 (-) exchange activity in the presence of K(+) as well as Cs(+), Li(+), and Rb(+) In summary, our results strongly suggest that Ae4 is an electroneutral Cl(-)/nonselective cation-HCO3 (-) exchanger. We postulate that the physiological role of Ae4 in secretory cells is to promote Cl(-) influx in exchange for K(+)(Na(+)) and HCO3 (-) ions.
Collapse
Affiliation(s)
- Gaspar Peña-Münzenmayer
- Secretory Mechanisms and Dysfunction Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD 20892
| | - Alvin T George
- Secretory Mechanisms and Dysfunction Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD 20892
| | - Gary E Shull
- Department of Molecular Genetics, Biochemistry, and Microbiology, University of Cincinnati College of Medicine, Cincinnati, OH 45267
| | - James E Melvin
- Secretory Mechanisms and Dysfunction Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD 20892
| | - Marcelo A Catalán
- Secretory Mechanisms and Dysfunction Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD 20892
| |
Collapse
|
13
|
Peña-Münzenmayer G, Catalán MA, Kondo Y, Jaramillo Y, Liu F, Shull GE, Melvin JE. Ae4 (Slc4a9) Anion Exchanger Drives Cl- Uptake-dependent Fluid Secretion by Mouse Submandibular Gland Acinar Cells. J Biol Chem 2015; 290:10677-88. [PMID: 25745107 DOI: 10.1074/jbc.m114.612895] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2014] [Indexed: 12/22/2022] Open
Abstract
Transcellular Cl(-) movement across acinar cells is the rate-limiting step for salivary gland fluid secretion. Basolateral Nkcc1 Na(+)-K(+)-2Cl(-) cotransporters play a critical role in fluid secretion by promoting the intracellular accumulation of Cl(-) above its equilibrium potential. However, salivation is only partially abolished in the absence of Nkcc1 cotransporter activity, suggesting that another Cl(-) uptake pathway concentrates Cl(-) ions in acinar cells. To identify alternative molecular mechanisms, we studied mice lacking Ae2 and Ae4 Cl(-)/HCO3 (-) exchangers. We found that salivation stimulated by muscarinic and β-adrenergic receptor agonists was normal in the submandibular glands of Ae2(-/-) mice. In contrast, saliva secretion was reduced by 35% in Ae4(-/-) mice. The decrease in salivation was not related to loss of Na(+)-K(+)-2Cl(-) cotransporter or Na(+)/H(+) exchanger activity in Ae4(-/-) mice but correlated with reduced Cl(-) uptake during β-adrenergic receptor activation of cAMP signaling. Direct measurements of Cl(-)/HCO3 (-) exchanger activity revealed that HCO3 (-)-dependent Cl(-) uptake was reduced in the acinar cells of Ae2(-/-) and Ae4(-/-) mice. Moreover, Cl(-)/HCO3 (-) exchanger activity was nearly abolished in double Ae4/Ae2 knock-out mice, suggesting that most of the Cl(-)/HCO3 (-) exchanger activity in submandibular acinar cells depends on Ae2 and Ae4 expression. In conclusion, both Ae2 and Ae4 anion exchangers are functionally expressed in submandibular acinar cells; however, only Ae4 expression appears to be important for cAMP-dependent regulation of fluid secretion.
Collapse
Affiliation(s)
- Gaspar Peña-Münzenmayer
- From the Secretory Mechanisms and Dysfunction Section, Division of Intramural Research, NIDCR, National Institutes of Health, Bethesda, Maryland 20892
| | - Marcelo A Catalán
- From the Secretory Mechanisms and Dysfunction Section, Division of Intramural Research, NIDCR, National Institutes of Health, Bethesda, Maryland 20892
| | - Yusuke Kondo
- From the Secretory Mechanisms and Dysfunction Section, Division of Intramural Research, NIDCR, National Institutes of Health, Bethesda, Maryland 20892, the Department of Oral Reconstruction and Rehabilitation, Kyushu Dental University, Kitakyushu, Fukuoka, Japan
| | - Yasna Jaramillo
- From the Secretory Mechanisms and Dysfunction Section, Division of Intramural Research, NIDCR, National Institutes of Health, Bethesda, Maryland 20892
| | - Frances Liu
- From the Secretory Mechanisms and Dysfunction Section, Division of Intramural Research, NIDCR, National Institutes of Health, Bethesda, Maryland 20892
| | - Gary E Shull
- the Department of Molecular Genetics, Biochemistry, and Microbiology, University of Cincinnati College of Medicine, Cincinnati, Ohio 45267, and
| | - James E Melvin
- From the Secretory Mechanisms and Dysfunction Section, Division of Intramural Research, NIDCR, National Institutes of Health, Bethesda, Maryland 20892,
| |
Collapse
|
14
|
Catalán MA, Peña-Munzenmayer G, Melvin JE. Ca²⁺-dependent K⁺ channels in exocrine salivary glands. Cell Calcium 2014; 55:362-8. [PMID: 24559652 DOI: 10.1016/j.ceca.2014.01.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2013] [Revised: 01/14/2014] [Accepted: 01/21/2014] [Indexed: 11/28/2022]
Abstract
In the last 15 years, remarkable progress has been realized in identifying the genes that encode the ion-transporting proteins involved in exocrine gland function, including salivary glands. Among these proteins, Ca(2+)-dependent K(+) channels take part in key functions including membrane potential regulation, fluid movement and K(+) secretion in exocrine glands. Two K(+) channels have been identified in exocrine salivary glands: (1) a Ca(2+)-activated K(+) channel of intermediate single channel conductance encoded by the KCNN4 gene, and (2) a voltage- and Ca(2+)-dependent K(+) channel of large single channel conductance encoded by the KCNMA1 gene. This review focuses on the physiological roles of Ca(2+)-dependent K(+) channels in exocrine salivary glands. We also discuss interesting recent findings on the regulation of Ca(2+)-dependent K(+) channels by protein-protein interactions that may significantly impact exocrine gland physiology.
Collapse
Affiliation(s)
- Marcelo A Catalán
- Secretory Mechanisms and Dysfunction Section (SMDS), National Institute of Dental and Craniofacial Research, National Institutes of Health, 10 Center Drive, Building 10/Room 5N102, Bethesda, MD 20892, USA.
| | - Gaspar Peña-Munzenmayer
- Secretory Mechanisms and Dysfunction Section (SMDS), National Institute of Dental and Craniofacial Research, National Institutes of Health, 10 Center Drive, Building 10/Room 5N102, Bethesda, MD 20892, USA
| | - James E Melvin
- Secretory Mechanisms and Dysfunction Section (SMDS), National Institute of Dental and Craniofacial Research, National Institutes of Health, 10 Center Drive, Building 10/Room 5N102, Bethesda, MD 20892, USA.
| |
Collapse
|
15
|
Yin H, Cabrera-Perez J, Lai Z, Michael D, Weller M, Swaim WD, Liu X, Catalán MA, Rocha EM, Ismail N, Afione S, Rana NA, Di Pasquale G, Alevizos I, Ambudkar I, Illei GG, Chiorini JA. Association of bone morphogenetic protein 6 with exocrine gland dysfunction in patients with Sjögren's syndrome and in mice. ACTA ACUST UNITED AC 2014; 65:3228-38. [PMID: 23982860 DOI: 10.1002/art.38123] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2012] [Accepted: 08/01/2013] [Indexed: 11/07/2022]
Abstract
OBJECTIVE Primary Sjögren's syndrome (SS) is characterized by autoimmune activation and loss of function in secretory epithelia. The present study was undertaken to investigate and characterize changes in the epithelia associated with the loss of gland function in primary SS. METHODS To identify changes in epithelial gene expression, custom microarrays were probed with complementary RNA (cRNA) isolated from minor salivary glands (MSGs) of female patients with primary SS who had low focus scores and low salivary flow rates, and the results were compared with those obtained using cRNA from the MSGs of sex-matched healthy volunteers. The effect of bone morphogenetic protein 6 (BMP-6) on salivary gland function was tested using adeno-associated virus-mediated gene transfer to the salivary glands of C57BL/6 mice. RESULTS A significant increase in expression of BMP-6 was observed in RNA isolated from SS patients compared with healthy volunteers. Overexpression of BMP-6 locally in the salivary or lacrimal glands of mice resulted in the loss of fluid secretion as well as changes in the connective tissue of the salivary gland. Assessment of the fluid movement in either isolated acinar cells from mice overexpressing BMP-6 or a human salivary gland cell line cultured with BMP-6 revealed a loss in volume regulation in these cells. Lymphocytic infiltration in the submandibular gland of BMP-6 vector-treated mice was increased. No significant changes in the production of proinflammatory cytokines or autoantibodies associated with SS (anti-Ro/SSA and anti-La/SSB) were found after BMP-6 overexpression. CONCLUSION In addition to identifying BMP-6 expression in association with xerostomia and xerophthalmia in primary SS, the present results suggest that BMP-6-induced salivary and lacrimal gland dysfunction in primary SS is independent of the autoantibodies and immune activation associated with the disease.
Collapse
Affiliation(s)
- Hongen Yin
- National Institute of Dental and Craniofacial Research, NIH, Bethesda, Maryland
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
16
|
Abstract
Transient receptor potential vanilloid subtype 4 (TRPV4) is a ligand-gated nonselective cation channel that participates in the transduction of mechanical and osmotic stimuli in different tissues. TRPV4 is activated by endogenous arachidonic acid metabolites, 4α-phorbol-12,13 didecanoate, GSK1016790A, moderate heat, and mechanical stress. TRPV4 is expressed in the salivary glands, but its expression pattern and function are poorly understood. The aim of this study was to evaluate the functional role of TRPV4 channels in the mouse submandibular gland. Using RT-PCR and Western blot analysis, we detected expression of TRPV4 message and protein, respectively, in the submandibular gland. Immunolocalization studies showed that TRPV4 targeted to the basolateral membrane of mouse submandibular gland acinar cells. Pharmacological TRPV4 activation using the selective agonist GSK1016790A caused Ca(2+) influx in isolated acinar cells in a basal-to-apical wave. Consistent with these observations, GSK1016790A elicited salivation in the perfused submandibular gland that was dependent on extracellular Ca(2+). In summary, we report that activation of TRPV4 channels induced Ca(2+) influx and salivation and, thus, may contribute a novel nonadrenergic, noncholinergic secretion pathway in the mouse submandibular gland.
Collapse
Affiliation(s)
- Yan Zhang
- Secretory Mechanisms and Dysfunction Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland
| | - Marcelo A. Catalán
- Secretory Mechanisms and Dysfunction Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland
| | - James E. Melvin
- Secretory Mechanisms and Dysfunction Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland
| |
Collapse
|
17
|
Patterson K, Catalán MA, Melvin JE, Yule DI, Crampin EJ, Sneyd J. A quantitative analysis of electrolyte exchange in the salivary duct. Am J Physiol Gastrointest Liver Physiol 2012; 303:G1153-63. [PMID: 22899825 PMCID: PMC3517652 DOI: 10.1152/ajpgi.00364.2011] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
A healthy salivary gland secretes saliva in two stages. First, acinar cells generate primary saliva, a plasma-like, isotonic fluid high in Na(+) and Cl(-). In the second stage, the ducts exchange Na(+) and Cl(-) for K(+) and HCO(3)(-), producing a hypotonic final saliva with no apparent loss in volume. We have developed a tool that aims to understand how the ducts achieve this electrolyte exchange while maintaining the same volume. This tool is part of a larger multiscale model of the salivary gland and can be used at the duct or gland level to investigate the effects of genetic and chemical alterations. In this study, we construct a radially symmetric mathematical model of the mouse salivary gland duct, representing the lumen, the cell, and the interstitium. For a given flow and primary saliva composition, we predict the potential differences and the luminal and cytosolic concentrations along a duct. Our model accounts well for experimental data obtained in wild-type animals as well as knockouts and chemical inhibitors. Additionally, the luminal membrane potential of the duct cells is predicted to be very depolarized compared with acinar cells. We investigate the effects of an electrogenic vs. electroneutral anion exchanger in the luminal membrane on concentration and the potential difference across the luminal membrane as well as how impairing the cystic fibrosis transmembrane conductance regulator channel affects other ion transporting mechanisms. Our model suggests the electrogenicity of the anion exchanger has little effect in the submandibular duct.
Collapse
Affiliation(s)
- Kate Patterson
- Dept. of Mathematics, Univ. of Auckland, Auckland, New Zealand.
| | - Marcelo A. Catalán
- 2Secretory Mechanisms and Dysfunction Section, Division of Intramural Research, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland;
| | - James E. Melvin
- 2Secretory Mechanisms and Dysfunction Section, Division of Intramural Research, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland;
| | - David I. Yule
- 3Department of Pharmacology and Physiology and the Center for Oral Biology, University of Rochester Medical Center, Rochester, New York; and
| | - Edmund J. Crampin
- 4Auckland Bioengineering Institute and Department of Engineering Science, University of Auckland, Auckland, New Zealand
| | - James Sneyd
- 1Department of Mathematics, University of Auckland, Auckland, New Zealand;
| |
Collapse
|
18
|
Catalán MA, Flores CA, González-Begne M, Zhang Y, Sepúlveda FV, Melvin JE. Severe defects in absorptive ion transport in distal colons of mice that lack ClC-2 channels. Gastroenterology 2012; 142:346-54. [PMID: 22079595 PMCID: PMC3267842 DOI: 10.1053/j.gastro.2011.10.037] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/14/2011] [Revised: 10/25/2011] [Accepted: 10/26/2011] [Indexed: 01/05/2023]
Abstract
BACKGROUND & AIMS The fluid secretion model predicts that intestinal obstruction disorders can be alleviated by promoting epithelial Cl(-) secretion. The adenosine 3',5'-cyclic monophosphate (cAMP)-activated anion channel CFTR mediates Cl(-)-dependent fluid secretion in the intestine. Although the role of the ClC-2 channel has not been determined in the intestine, this voltage-gated Cl(-) channel might compensate for the secretory defects observed in patients with cystic fibrosis and other chronic constipation disorders. We investigated whether mice that lack ClC-2 channels (Clcn2(-/-)) have defects in intestinal ion transport. METHODS Immunolocalization and immunoblot analyses were used to determine the cellular localization and the amount of ClC-2 expressed in mouse early distal colon (EDC) and late distal colon (LDC). Colon sheets from wild-type and Clcn2(-/-) littermates were mounted in Ussing chambers to determine transepithelial bioelectrical parameters and Na(+), K(+), and Cl(-) fluxes. RESULTS Expression of ClC-2 was higher in the basolateral membrane of surface cells in the EDC compared with the LDC, with little expression in crypts. Neither cAMP nor Ca(2+)-induced secretion of Cl(-) was affected in the EDC or LDC of Clcn2(-/-) mice, whereas the amiloride-sensitive short-circuit current was increased approximately 3-fold in Clcn2(-/-) EDC compared with control littermates. Conversely, electroneutral Na(+), K(+), and Cl(-) absorption was dramatically reduced in colons of Clcn2(-/-) mice. CONCLUSIONS Basolateral ClC-2 channels are required for colonic electroneutral absorption of NaCl and KCl. The increase in the amiloride-sensitive short-circuit current in Clcn2(-/-) mice revealed a compensatory mechanism that is activated in the colons of mice that lack the ClC-2 channel.
Collapse
Affiliation(s)
- Marcelo A. Catalán
- Secretory Mechanisms and Dysfunction Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, 10 Center Drive, Building 10/Room 5N102, Bethesda, MD 20892 USA
| | | | - Mireya González-Begne
- Center for Oral Biology, University of Rochester Medical Center, Rochester, NY 14642 USA
| | - Yan Zhang
- Secretory Mechanisms and Dysfunction Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, 10 Center Drive, Building 10/Room 5N102, Bethesda, MD 20892 USA
| | | | - James E. Melvin
- Secretory Mechanisms and Dysfunction Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, 10 Center Drive, Building 10/Room 5N102, Bethesda, MD 20892 USA
| |
Collapse
|
19
|
Catalán MA, Scott-Anne K, Klein MI, Koo H, Bowen WH, Melvin JE. Elevated incidence of dental caries in a mouse model of cystic fibrosis. PLoS One 2011; 6:e16549. [PMID: 21304986 PMCID: PMC3031584 DOI: 10.1371/journal.pone.0016549] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2010] [Accepted: 12/23/2010] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Dental caries is the single most prevalent and costly infectious disease worldwide, affecting more than 90% of the population in the U.S. The development of dental cavities requires the colonization of the tooth surface by acid-producing bacteria, such as Streptococcus mutans. Saliva bicarbonate constitutes the main buffering system which neutralizes the pH fall generated by the plaque bacteria during sugar metabolism. We found that the saliva pH is severely decreased in a mouse model of cystic fibrosis disease (CF). Given the close relationship between pH and caries development, we hypothesized that caries incidence might be elevated in the mouse CF model. METHODOLOGY/PRINCIPAL FINDINGS We induced carious lesions in CF and wildtype mice by infecting their oral cavity with S. mutans, a well-studied cariogenic bacterium. After infection, the mice were fed a high-sucrose diet for 5 weeks (diet 2000). The mice were then euthanized and their jaws removed for caries scoring and bacterial counting. A dramatic increase in caries and severity of lesions scores were apparent in CF mice compared to their wildtype littermates. The elevated incidence of carious lesions correlated with a striking increase in the S. mutans viable population in dental plaque (20-fold increase in CF vs. wildtype mice; p value < 0.003; t test). We also found that the pilocarpine-stimulated saliva bicarbonate concentration was significantly reduced in CF mice (16 ± 2 mM vs. 31 ± 2 mM, CF and wildtype mice, respectively; p value < 0.01; t test). CONCLUSIONS/SIGNIFICANCE Considering that bicarbonate is the most important pH buffering system in saliva, and the adherence and survival of aciduric bacteria such as S. mutans are enhanced at low pH values, we speculate that the decrease in the bicarbonate content and pH buffering of the saliva is at least partially responsible for the increased severity of lesions observed in the CF mouse.
Collapse
Affiliation(s)
- Marcelo A. Catalán
- Department of Pharmacology and Physiology, University of Rochester Medical Center, Rochester, New York, United States of America
| | - Kathleen Scott-Anne
- Center for Oral Biology, University of Rochester Medical Center, Rochester, New York, United States of America
| | - Marlise I. Klein
- Center for Oral Biology, University of Rochester Medical Center, Rochester, New York, United States of America
| | - Hyun Koo
- Center for Oral Biology, University of Rochester Medical Center, Rochester, New York, United States of America
| | - William H. Bowen
- Center for Oral Biology, University of Rochester Medical Center, Rochester, New York, United States of America
| | - James E. Melvin
- Department of Pharmacology and Physiology, University of Rochester Medical Center, Rochester, New York, United States of America
- * E-mail:
| |
Collapse
|
20
|
Abstract
Fluid secretion by exocrine glands requires the coordinated activity of multiple water and ion transporter and channel proteins. The molecular cloning of many of the transporter molecules involved in fluid secretion has yielded a better understanding of the fluid secretion process. Mouse salivary glands are easily accessible model systems for the study of exocrine gland secretion at the cellular and organ level. Indeed, the characterization of mice with null mutations in many of the water and ion transporter and channel genes has demonstrated the physiological roles of individual proteins. This overview will focus on recent developments in determining the molecular identification of the proteins that are involved in the fluid secretion process.
Collapse
Affiliation(s)
- Marcelo A Catalán
- Department of Pharmacology and Physiology, University of Rochester Medical Center, New York, NY 14642, USA
| | | | | |
Collapse
|
21
|
Romanenko VG, Catalán MA, Brown DA, Putzier I, Hartzell HC, Marmorstein AD, Gonzalez-Begne M, Rock JR, Harfe BD, Melvin JE. Tmem16A encodes the Ca2+-activated Cl- channel in mouse submandibular salivary gland acinar cells. J Biol Chem 2010; 285:12990-3001. [PMID: 20177062 DOI: 10.1074/jbc.m109.068544] [Citation(s) in RCA: 160] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Activation of an apical Ca(2+)-dependent Cl(-) channel (CaCC) is the rate-limiting step for fluid secretion in many exocrine tissues. Here, we compared the properties of native CaCC in mouse submandibular salivary gland acinar cells to the Ca(2+)-gated Cl(-) currents generated by Tmem16A and Best2, members from two distinct families of Ca(2+)-activated Cl(-) channels found in salivary glands. Heterologous expression of Tmem16A and Best2 transcripts in HEK293 cells produced Ca(2+)-activated Cl(-) currents with time and voltage dependence and inhibitor sensitivity that resembled the Ca(2+)-activated Cl(-) current found in native salivary acinar cells. Best2(-/-) and Tmem16A(-/-) mice were used to further characterize the role of these channels in the exocrine salivary gland. The amplitude and the biophysical footprint of the Ca(2+)-activated Cl(-) current in submandibular gland acinar cells from Best2-deficient mice were the same as in wild type cells. Consistent with this observation, the fluid secretion rate in Best2 null mice was comparable with that in wild type mice. In contrast, submandibular gland acinar cells from Tmem16A(-/-) mice lacked a Ca(2+)-activated Cl(-) current and a Ca(2+)-mobilizing agonist failed to stimulate Cl(-) efflux, requirements for fluid secretion. Furthermore, saliva secretion was abolished by the CaCC inhibitor niflumic acid in wild type and Best2(-/-) mice. Our results demonstrate that both Tmem16A and Best2 generate Ca(2+)-activated Cl(-) current in vitro with similar properties to those expressed in native cells, yet only Tmem16A appears to be a critical component of the acinar Ca(2+)-activated Cl(-) channel complex that is essential for saliva production by the submandibular gland.
Collapse
Affiliation(s)
- Victor G Romanenko
- Department of Pharmacology and Physiology, University of Rochester, Rochester, New York 14642, USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|
22
|
Catalán MA, Nakamoto T, Gonzalez-Begne M, Camden JM, Wall SM, Clarke LL, Melvin JE. Cftr and ENaC ion channels mediate NaCl absorption in the mouse submandibular gland. J Physiol 2009; 588:713-24. [PMID: 20026617 DOI: 10.1113/jphysiol.2009.183541] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Cystic fibrosis is caused by mutations in CFTR, the cystic fibrosis transmembrane conductance regulator gene. Disruption of CFTR-mediated anion conductance results in defective fluid and electrolyte movement in the epithelial cells of organs such as the pancreas, airways and sweat glands, but the function of CFTR in salivary glands is unclear. Salivary gland acinar cells produce an isotonic, plasma-like fluid, which is subsequently modified by the ducts to produce a hypotonic, NaCl-depleted final saliva. In the present study we investigated whether submandibular salivary glands (SMGs) in F508 mice (Cftr(F/F)) display ion transport defects characteristic of cystic fibrosis in other tissues. Immunolocalization and whole-cell recordings demonstrated that Cftr and the epithelial Na(+) (ENaC) channels are co-expressed in the apical membrane of submandibular duct cells, consistent with the significantly higher saliva [NaCl] observed in vivo in Cftr(F/F) mice. In contrast, Cftr and ENaC channels were not detected in acinar cells, nor was saliva production affected in Cftr(F/F) mice, implying that Cftr contributes little to the fluid secretion process in the mouse SMG. To identify the source of the NaCl absorption defect in Cftr(F/F) mice, saliva was collected from ex vivo perfused SMGs. Cftr(F/F) glands secreted saliva with significantly increased [NaCl]. Moreover, pharmacological inhibition of either Cftr or ENaC in the ex vivo SMGs mimicked the Cftr(F/F) phenotype. In summary, our results demonstrate that NaCl absorption requires and is likely to be mediated by functionally dependent Cftr and ENaC channels localized to the apical membranes of mouse salivary gland duct cells.
Collapse
Affiliation(s)
- Marcelo A Catalán
- Department of Pharmacology and Physiology, University of Rochester Medical Center, Rochester, NY 14620, USA
| | | | | | | | | | | | | |
Collapse
|
23
|
Nakamoto T, Brown DA, Catalán MA, Gonzalez-Begne M, Romanenko VG, Melvin JE. Purinergic P2X7 receptors mediate ATP-induced saliva secretion by the mouse submandibular gland. J Biol Chem 2008; 284:4815-22. [PMID: 19097994 DOI: 10.1074/jbc.m808597200] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Salivary glands express multiple isoforms of P2X and P2Y nucleotide receptors, but their in vivo physiological roles are unclear. P2 receptor agonists induced salivation in an ex vivo submandibular gland preparation. The nucleotide selectivity sequence of the secretion response was BzATP >> ATP > ADP >> UTP, and removal of external Ca(2+) dramatically suppressed the initial ATP-induced fluid secretion ( approximately 85%). Together, these results suggested that P2X receptors are the major purinergic receptor subfamily involved in the fluid secretion process. Mice with targeted disruption of the P2X(7) gene were used to evaluate the role of the P2X(7) receptor in nucleotide-evoked fluid secretion. P2X(7) receptor protein and BzATP-activated inward cation currents were absent, and importantly, purinergic receptor agonist-stimulated salivation was suppressed by more than 70% in submandibular glands from P2X(7)-null mice. Consistent with these observations, the ATP-induced increases in [Ca(2+)](i) were nearly abolished in P2X(7)(-/-) submandibular acinar and duct cells. ATP appeared to also act through the P2X(7) receptor to inhibit muscarinic-induced fluid secretion. These results demonstrate that the ATP-sensitive P2X(7) receptor regulates fluid secretion in the mouse submandibular gland.
Collapse
Affiliation(s)
- Tetsuji Nakamoto
- Center for Oral Biology, University of Rochester Medical Center, Rochester, New York 14642, USA
| | | | | | | | | | | |
Collapse
|
24
|
Romanenko VG, Nakamoto T, Catalán MA, Gonzalez-Begne M, Schwartz GJ, Jaramillo Y, Sepúlveda FV, Figueroa CD, Melvin JE. Clcn2 encodes the hyperpolarization-activated chloride channel in the ducts of mouse salivary glands. Am J Physiol Gastrointest Liver Physiol 2008; 295:G1058-67. [PMID: 18801913 PMCID: PMC2584831 DOI: 10.1152/ajpgi.90384.2008] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Transepithelial Cl(-) transport in salivary gland ducts is a major component of the ion reabsorption process, the final stage of saliva production. It was previously demonstrated that a Cl(-) current with the biophysical properties of ClC-2 channels dominates the Cl(-) conductance of unstimulated granular duct cells in the mouse submandibular gland. This inward-rectifying Cl(-) current is activated by hyperpolarization and elevated intracellular Cl(-) concentration. Here we show that ClC-2 immunolocalized to the basolateral region of acinar and duct cells in mouse salivary glands, whereas its expression was most robust in granular and striated duct cells. Consistent with this observation, nearly 10-fold larger ClC-2-like currents were observed in granular duct cells than the acinar cells obtained from submandibular glands. The loss of inward-rectifying Cl(-) current in cells from Clcn2(-/-) mice confirmed the molecular identity of the channel responsible for these currents as ClC-2. Nevertheless, both in vivo and ex vivo fluid secretion assays failed to identify significant changes in the ion composition, osmolality, or salivary flow rate of Clcn2(-/-) mice. Additionally, neither a compensatory increase in Cftr Cl(-) channel protein expression nor in Cftr-like Cl(-) currents were detected in Clcn2 null mice, nor did it appear that ClC-2 was important for blood-organ barrier function. We conclude that ClC-2 is the inward-rectifying Cl(-) channel in duct cells, but its expression is not apparently required for the ion reabsorption or the barrier function of salivary ductal epithelium.
Collapse
Affiliation(s)
- Victor G. Romanenko
- The Center for Oral Biology and the Department of Pharmacology and Physiology, and Department of Pediatrics, University of Rochester School of Medicine and Dentistry, Rochester, New York; Centro de Estudios Científicos, Valdivia; and Instituto de Anatomía, Histología y Patología. Universidad Austral de Chile, Valdivia, Chile
| | - Tetsuji Nakamoto
- The Center for Oral Biology and the Department of Pharmacology and Physiology, and Department of Pediatrics, University of Rochester School of Medicine and Dentistry, Rochester, New York; Centro de Estudios Científicos, Valdivia; and Instituto de Anatomía, Histología y Patología. Universidad Austral de Chile, Valdivia, Chile
| | - Marcelo A. Catalán
- The Center for Oral Biology and the Department of Pharmacology and Physiology, and Department of Pediatrics, University of Rochester School of Medicine and Dentistry, Rochester, New York; Centro de Estudios Científicos, Valdivia; and Instituto de Anatomía, Histología y Patología. Universidad Austral de Chile, Valdivia, Chile
| | - Mireya Gonzalez-Begne
- The Center for Oral Biology and the Department of Pharmacology and Physiology, and Department of Pediatrics, University of Rochester School of Medicine and Dentistry, Rochester, New York; Centro de Estudios Científicos, Valdivia; and Instituto de Anatomía, Histología y Patología. Universidad Austral de Chile, Valdivia, Chile
| | - George J. Schwartz
- The Center for Oral Biology and the Department of Pharmacology and Physiology, and Department of Pediatrics, University of Rochester School of Medicine and Dentistry, Rochester, New York; Centro de Estudios Científicos, Valdivia; and Instituto de Anatomía, Histología y Patología. Universidad Austral de Chile, Valdivia, Chile
| | - Yasna Jaramillo
- The Center for Oral Biology and the Department of Pharmacology and Physiology, and Department of Pediatrics, University of Rochester School of Medicine and Dentistry, Rochester, New York; Centro de Estudios Científicos, Valdivia; and Instituto de Anatomía, Histología y Patología. Universidad Austral de Chile, Valdivia, Chile
| | - Francisco V. Sepúlveda
- The Center for Oral Biology and the Department of Pharmacology and Physiology, and Department of Pediatrics, University of Rochester School of Medicine and Dentistry, Rochester, New York; Centro de Estudios Científicos, Valdivia; and Instituto de Anatomía, Histología y Patología. Universidad Austral de Chile, Valdivia, Chile
| | - Carlos D. Figueroa
- The Center for Oral Biology and the Department of Pharmacology and Physiology, and Department of Pediatrics, University of Rochester School of Medicine and Dentistry, Rochester, New York; Centro de Estudios Científicos, Valdivia; and Instituto de Anatomía, Histología y Patología. Universidad Austral de Chile, Valdivia, Chile
| | - James E. Melvin
- The Center for Oral Biology and the Department of Pharmacology and Physiology, and Department of Pediatrics, University of Rochester School of Medicine and Dentistry, Rochester, New York; Centro de Estudios Científicos, Valdivia; and Instituto de Anatomía, Histología y Patología. Universidad Austral de Chile, Valdivia, Chile
| |
Collapse
|
25
|
Srivastava A, Romanenko VG, Gonzalez-Begne M, Catalán MA, Melvin JE. A variant of the Ca2+-activated Cl channel Best3 is expressed in mouse exocrine glands. J Membr Biol 2008; 222:43-54. [PMID: 18414923 DOI: 10.1007/s00232-008-9098-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2007] [Accepted: 02/21/2008] [Indexed: 11/27/2022]
Abstract
Fluid secretion by exocrine glands requires the activation of an apical Ca2+-dependent Cl channel, the molecular identity of which is unknown. We found that mouse exocrine glands expressed an alternately spliced variant of Best3, a member of the Bestrophin (Vmd2) Ca2+-activated Cl channel gene family, whereas the heart expressed full-length Best3. The spliced transcript lacked exons 2, 3 and 6 (Best3-Delta2,3,6) and is predicted to generate an in-frame protein missing the entire cytoplasmic N terminus, the initial two transmembrane domains and part of the first intracellular loop. In addition to exocrine glands, the Best3-Delta2,3,6 splice variant transcript was detected in lung, testis and kidney. The parotid gland and heart expressed proteins of the predicted size for Best3-Delta2,3,6 and full-length Best3, respectively, that targeted to the plasma membrane in HEK293 cells. HEK293 cells expressing Best3 displayed Ca2+-dependent Cl(-) currents that were sensitive to the Cl channel blocker DIDS. In contrast, no Ca2+-dependent Cl(-) currents were detected in cells expressing Best3-Delta2,3,6. Cotransfection of Best3-Delta2,3,6 with Best3 or Best2 (also expressed in salivary gland acinar cells) had no significant effects on the currents generated by either of these Ca2+-dependent Cl channels. Our results demonstrate that exocrine glands express a unique splice variant of Best3. Nevertheless, Best3-Delta2,3,6 does not produce Ca2+-dependent Cl(-) currents, nor does it regulate the activity of Best2 or the full-length Best3 channel.
Collapse
Affiliation(s)
- Alaka Srivastava
- Center for Oral Biology, Medical Center, University of Rochester School of Medicine and Dentistry, 601 Elmwood Ave., Box 611, Rochester, NY 14642, USA
| | | | | | | | | |
Collapse
|
26
|
Mata LJ, Catalán MA, Gordon JE. Studies of diarrheal disease in Central America. IX. Shigella carriers among young children of a heavily seeded Guatemalan convalescent home. Am J Trop Med Hyg 1966; 15:632-8. [PMID: 5328734] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
|