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Ge H, Di G, Li B, Han W, Song P, Han S, Wang D, Chen P. Reticulated Retinoic Acid Synthesis is Implicated in the Pathogenesis of Dry Eye in Aqp5 Deficiency Mice. Invest Ophthalmol Vis Sci 2024; 65:25. [PMID: 39017635 PMCID: PMC11262545 DOI: 10.1167/iovs.65.8.25] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2024] [Accepted: 07/01/2024] [Indexed: 07/18/2024] Open
Abstract
Purpose Abnormalities in aquaporins are implicated in the pathological progression of dry eye syndrome. Retinoic acid (RA) regulates cellular proliferation, differentiation, and apoptosis in the cornea, thereby being associated with dry eye disease (DED). The objective of this study is to explore the underlying mechanisms responsible for RA metabolic abnormalities in corneas lacking aquaporin 5 (AQP5). Methods Dry eye (DE) models were induced via subcutaneous scopolamine hydrobromide. Aqp5 knockout (Aqp5-/-) mice and DE mice were utilized to assess corneal epithelial alterations. Tear secretion, goblet cell counts, and corneal punctate defects were evaluated. The impact of Aqp5 on RA-related enzymes and receptors was investigated using pharmacological RA or SR (A JunB inhibitor), a transcription factor JunB inhibitor, treatment in mouse corneal epithelial cells (CECs), or human corneal epithelial cells (HCECs). The HCECs and NaCl-treated HCECs underwent quantitative real-time PCR (qRT-PCR), immunofluorescent, Western blot, and TUNEL assays. The regulation of transcription factor JunB on Aldh1a1 was explored via ChIP-PCR. Results Aqp5 and Aldh1a1 were reduced in both CECs of DE mice and NaCl-induced HCECs. Aqp5-/- mice exhibited DE phenotype and reduced Aldh1a1. RA treatment reduced apoptosis, promoted proliferation, and improved the DE phenotype in Aqp5-/- mice. JunB enrichment in the Aldh1a1 promoter was identified by ChIP-PCR. SR significantly increased Aldh1a1 expression, Ki67, and ΔNp63-positive cells, and decreased TUNEL-positive cells in CECs and HCECs. Conclusions Our findings demonstrated the downregulation of Aqp5 expression and aberrant RA metabolism in DE conditions. Knockout of Aqp5 resulted in reduced production of RA through activation of JunB, subsequently leading to the manifestation of DE symptoms.
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Affiliation(s)
- Huanhuan Ge
- School of Basic Medicine, Qingdao University, Qingdao, China
| | - Guohu Di
- School of Basic Medicine, Qingdao University, Qingdao, China
- Institute of Stem Cell Regeneration Medicine, School of Basic Medicine, Qingdao University, Qingdao, China
| | - Bin Li
- School of Basic Medicine, Qingdao University, Qingdao, China
| | - Wenshuo Han
- School of Basic Medicine, Qingdao University, Qingdao, China
| | - Peirong Song
- School of Basic Medicine, Qingdao University, Qingdao, China
| | - Shiheng Han
- School of Basic Medicine, Qingdao University, Qingdao, China
| | - Dianqiang Wang
- Aier School Ophthalmology, Central South University, Changsha, Hunan, P. R. China
- Department of Ophthalmology, Qingdao Aier Eye Hospital, Qingdao, China
| | - Peng Chen
- School of Basic Medicine, Qingdao University, Qingdao, China
- Institute of Stem Cell Regeneration Medicine, School of Basic Medicine, Qingdao University, Qingdao, China
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Elekes G, Csapó V, Szarka D, Szalay L, Korsós MM, Tálosi D, Török D, Tóth-Molnár E. The Role of Aquaporin 4 in Lacrimal Gland Ductal Fluid Secretion in Mice. Invest Ophthalmol Vis Sci 2024; 65:30. [PMID: 38771571 PMCID: PMC11114615 DOI: 10.1167/iovs.65.5.30] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Accepted: 05/04/2024] [Indexed: 05/22/2024] Open
Abstract
Purpose Earlier reports highlighted the predominant presence of aquaporin 4 (AQP4) in the duct cells of rabbit lacrimal glands (LGs). Whereas significant alterations in AQP4 mRNA levels have been observed in experimental dry eye and during pregnancy, the impact of AQP4 in LG ductal fluid production remains unclear. In our recent work, the role of AQP4 in LG ductal fluid secretion was investigated utilizing wild type (WT) and AQP4 knock out (KO) mice. Methods Tear production was assessed in both WT and KO animals. Immunostaining was used to identify AQP4 protein. Duct segments were harvested from LGs of WT and KO mice. Fluid secretion and filtration permeability (Pf) were quantified using video-microscopy. Ductal tear production, elicited by a cell-permeable cAMP analogue (8-bromo cAMP), carbachol, vasoactive intestinal peptide (VIP), and phenylephrine (PHE), were assessed in both WT and KO ducts. Results A higher expression of AQP4 protein was noted in the duct cells from WT mice when compared to acinar cells. Pf did not show notable alterations between WT and AQP4 KO ducts. Carbachol elicited comparable secretory responses in ducts from both WT and KO animals. However, 8-bromo cAMP, VIP, and PHE stimulation resulted in decreased secretion in ducts from AQP4 KO LGs. Conclusions Our findings underscore the functional relevance of AQP4 in the fluid production of mouse LG ducts. AQP4 seems to play different roles in fluid secretions elicited by different secretagogues. Specifically, cAMP-mediated, and adrenergic agonist-related secretions were reduced in AQP4 KO ducts.
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Affiliation(s)
- Gréta Elekes
- Department of Ophthalmology, University of Szeged, Szeged, Hungary
| | - Virág Csapó
- Department of Ophthalmology, University of Szeged, Szeged, Hungary
| | - Dóra Szarka
- Department of Ophthalmology, University of Szeged, Szeged, Hungary
| | - László Szalay
- Department of Ophthalmology, University of Szeged, Szeged, Hungary
| | | | - Dorottya Tálosi
- Albert Szent-Gyorgyi Medical School, University of Szeged, Szeged, Hungary
| | - Dénes Török
- Department of Anatomy, University of Szeged, Szeged, Hungary
| | - Edit Tóth-Molnár
- Department of Ophthalmology, University of Szeged, Szeged, Hungary
- Faculty of Health Sciences and Social Studies, University of Szeged, Szeged, Hungary
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Zhao L, Chen R, Qu J, Yang L, Li Y, Ma L, Zang X, Qi X, Wang X, Zhou Q. Establishment of mouse model of neurotrophic keratopathy through TRPV1 neuronal ablation. Exp Eye Res 2024; 240:109814. [PMID: 38307190 DOI: 10.1016/j.exer.2024.109814] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Revised: 01/03/2024] [Accepted: 01/29/2024] [Indexed: 02/04/2024]
Abstract
Neurotrophic keratopathy (NK) is a challenging disease with the reduced innervation to the cornea. To establish a genetic and stable mouse model of NK, we utilized the TRPV1-DTR mice with intraperitoneal injection of diphtheria toxin (DT) to selectively eliminate TRPV1 neurons. After DT administration, the mice exhibited robust ablation of TRPV1 neurons in the trigeminal ganglion, accompanied with reduced corneal sensation and nerve density, as well as the decreased calcitonin-gene-related peptide (CGRP) and substance P levels. According to disease progression of TRPV1 neuronal ablation, tear secretion was reduced from day 3, which followed by corneal epithelial punctate lesions from day 7. From day 11 to day 16, the mice exhibited persistent corneal epithelial defects and stromal edema. By day 21, corneal ulceration and stromal melting were observed with the abundant inflammatory cell infiltration, corneal neovascularization, and enhanced cell apoptosis. Moreover, subconjunctival injection of CGRP delayed the NK progression with the characteristics of reduced severe corneal epithelial lesions and corneal inflammation. In addition, the impairments of conjunctival goblet cells, lacrimal gland, and meibomian gland were identified by the diminished expression of MUC5AC, AQP5, and PPARγ, respectively. Therefore, these results suggest that the TRPV1-DTR mice may serve as a reliable animal model for the research of NK pathogenesis.
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Affiliation(s)
- Leilei Zhao
- Medical College, Qingdao University, Qingdao, China
| | - Rong Chen
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Eye Institute of Shandong First Medical University, Qingdao, China
| | - Jingyu Qu
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Eye Institute of Shandong First Medical University, Qingdao, China
| | - Lingling Yang
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Eye Institute of Shandong First Medical University, Qingdao, China
| | - Ya Li
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Eye Institute of Shandong First Medical University, Qingdao, China
| | - Linyan Ma
- Medical College, Qingdao University, Qingdao, China
| | - Xinyi Zang
- Weifang Medical University, Weifang, China
| | - Xia Qi
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Eye Institute of Shandong First Medical University, Qingdao, China
| | - Xiaolei Wang
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Eye Institute of Shandong First Medical University, Qingdao, China.
| | - Qingjun Zhou
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Eye Institute of Shandong First Medical University, Qingdao, China.
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Bai Y, Zhang K, Cao X, Chen P. Aquaporins in lacrimal glands and their role in dry eye disease. Exp Eye Res 2023; 236:109676. [PMID: 37827442 DOI: 10.1016/j.exer.2023.109676] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 10/05/2023] [Accepted: 10/09/2023] [Indexed: 10/14/2023]
Abstract
Aging is the most important known risk factor for dry eye is aging, which is associated with changes in the structure and function of the lacrimal gland (LG) and characterized by atrophy, duct blocking lymphocyte infiltration, and reduced protein secretion. Aquaporins (AQP) have been proposed as a potential producer of exocrine gland fluids since exocrine secretion depends on the mobility of water. Therefore, the main topics of this review will be the expression, localization, and function of AQPs in LG. In addition, we review the mechanisms of fluid transport in exocrine gland fluid secretion and discuss the potential role of AQPs in dry eye.
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Affiliation(s)
- Ying Bai
- Department of Human Anatomy, Histology and Embryology, School of Basic Medicine, Qingdao University, Qingdao, 266071, Shandong Province, China
| | - Kaier Zhang
- Department of Human Anatomy, Histology and Embryology, School of Basic Medicine, Qingdao University, Qingdao, 266071, Shandong Province, China
| | - Xin Cao
- Department of Human Anatomy, Histology and Embryology, School of Basic Medicine, Qingdao University, Qingdao, 266071, Shandong Province, China
| | - Peng Chen
- Department of Human Anatomy, Histology and Embryology, School of Basic Medicine, Qingdao University, Qingdao, 266071, Shandong Province, China; Clinical Laboratory, Qingdao Central Hospital, The Second Affiliated Hospital of Medical College of Qingdao University, Qingdao, 266042, Shandong Province, China.
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Liu X, Cui Z, Chen X, Li Y, Qiu J, Huang Y, Wang X, Chen S, Luo Q, Chen P, Zhuang J, Yu K. Ferroptosis in the Lacrimal Gland Is Involved in Dry Eye Syndrome Induced by Corneal Nerve Severing. Invest Ophthalmol Vis Sci 2023; 64:27. [PMID: 37326593 DOI: 10.1167/iovs.64.7.27] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/17/2023] Open
Abstract
Purpose Dry eye syndrome (DES) is a prevalent postoperative complication after myopic corneal refractive surgeries and the main cause of postoperative dissatisfaction. Although great efforts have been made in recent decades, the molecular mechanism of postoperative DES remains poorly understood. Here, we used a series of bioinformatics approaches and experimental methods to investigate the potential mechanism involved in postoperative DES. Methods BALB/c mice were randomly divided into sham, unilateral corneal nerve cutting (UCNV) + saline, UCNV + vasoactive intestinal peptide (VIP), and UCNV + ferrostatin-1 (Fer-1, inhibitor of ferroptosis) groups. Corneal lissamine green dye and tear volume were measured before and two weeks after the surgery in all groups. Lacrimal glands were collected for secretory function testing, RNA sequencing, ferroptosis verification, and inflammatory factor detection. Results UCNV significantly induced bilateral decreases in tear secretion. Inhibition of the maturation and release of secretory vesicles was observed in bilateral lacrimal glands. More importantly, UCNV induced ferroptosis in bilateral lacrimal glands. Furthermore, UCNV significantly decreased VIP, a neural transmitter, in bilateral lacrimal glands, which increased Hif1a, the dominant transcription factor of transferrin receptor protein 1 (TfR1). Supplementary VIP inhibited ferroptosis, which decreased the inflammatory reaction and promoted the maturation and release of secretory vesicles. Supplementary VIP and Fer-1 improved tear secretion. Conclusions Our data suggest a novel mechanism by which UCNV induces bilateral ferroptosis through the VIP/Hif1a/TfR1 pathway, which might be a promising therapeutic target for DES-induced by corneal refractive surgeries.
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Affiliation(s)
- Xuan Liu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, No. 7 Jinsui Road, Tianhe District, Guangzhou, China
- Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Zedu Cui
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, No. 7 Jinsui Road, Tianhe District, Guangzhou, China
- Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Xi Chen
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, No. 7 Jinsui Road, Tianhe District, Guangzhou, China
- Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Yan Li
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, No. 7 Jinsui Road, Tianhe District, Guangzhou, China
- Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Jin Qiu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, No. 7 Jinsui Road, Tianhe District, Guangzhou, China
- Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Yuke Huang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, No. 7 Jinsui Road, Tianhe District, Guangzhou, China
- Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Xiao Wang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, No. 7 Jinsui Road, Tianhe District, Guangzhou, China
- Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Shuilian Chen
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, No. 7 Jinsui Road, Tianhe District, Guangzhou, China
- Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Qian Luo
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, No. 7 Jinsui Road, Tianhe District, Guangzhou, China
- Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Pei Chen
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, No. 7 Jinsui Road, Tianhe District, Guangzhou, China
- Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Jing Zhuang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, No. 7 Jinsui Road, Tianhe District, Guangzhou, China
- Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Keming Yu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, No. 7 Jinsui Road, Tianhe District, Guangzhou, China
- Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
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Involvement of aquaporin 5 in Sjögren's syndrome. Autoimmun Rev 2023; 22:103268. [PMID: 36621535 DOI: 10.1016/j.autrev.2023.103268] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Accepted: 01/04/2023] [Indexed: 01/07/2023]
Abstract
Sjögren's syndrome (SS) is a chronic autoimmune disease with the pathological hallmark of lymphoplasmacytic infiltration of exocrine glands - more specifically salivary and lacrimal glands - resulting in a diminished production of tears and saliva (sicca syndrome). The pathophysiology underscoring the mechanisms of the sicca symptoms in SS has still yet to be unraveled but recent advances have identified a cardinal role of aquaporin-5 (AQP5) as a key player in saliva secretion as well as salivary gland epithelial cell dysregulation. AQP5 expression and localization are significantly altered in salivary glands from patients and mice models of the disease, shedding light on a putative mechanism accounting for diminished salivary flow. Furthermore, aberrant expression and localization of AQP5 protein partners, such as prolactin-inducible protein and ezrin, may account for altered AQP5 localization in salivary glands from patients suffering from SS and are considered as new players in SS development. This review provides an overview of the role of AQP5 in SS salivary gland epithelial cell dysregulation, focusing on its trafficking and protein-protein interactions.
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Cao X, Di G, Bai Y, Zhang K, Wang Y, Zhao H, Wang D, Chen P. Aquaporin5 Deficiency Aggravates ROS/NLRP3 Inflammasome-Mediated Pyroptosis in the Lacrimal Glands. Invest Ophthalmol Vis Sci 2023; 64:4. [PMID: 36626177 PMCID: PMC9838588 DOI: 10.1167/iovs.64.1.4] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Purpose The pathogenesis of the lacrimal glands (LGs) is facilitated by inflammation mediated by the NACHT, LRR, and NLRP3 inflammasomes in dry eye disease. This research aimed to explore the protective effects of Aquaporin 5 (AQP5) on LGs by inhibiting reactive oxygen species (ROS) and the NLRP3 inflammasome. Methods AQP5 knockout (AQP5-/-) mice were used to evaluate pathological changes in LGs. ROS generation was detected with a dichlorodihydro-fluorescein diacetate assay. Lipid metabolism was assessed by Oil Red O staining. The reversal of the mitochondrial membrane potential was detected using a JC-1 fluorescent probe kit. The effect of AQP5 on NLRP3/caspase-1/Gasdermin-D (GSDMD)-mediated pyroptosis was examined using pharmacological treatment of N-acetyl L-cysteine or MCC950. Results AQP5 loss significantly increased ROS generation, lipid metabolism disorders, TUNEL-positive cells, and reversal of the mitochondrial membrane potential in the AQP5-/- LGs. NLRP3 upregulation, increased caspase-1 and GSDMD activity, and enhanced IL-1β release were detected in the AQP5-/- mouse LGs and primary LG epithelial cells. MCC950 significantly suppressed NLRP3 inflammasome-related pyroptosis induced by AQP5 deficiency in LGs and primary LG epithelial cells. Furthermore, we discovered that prestimulating the AQP5-/- primary LG epithelial cells with N-acetyl L-cysteine decreased NLRP3 expression, caspase-1 and GSDMD activity levels, and IL-1β release. Conclusions Our results revealed that AQP5 loss promoted NLRP3 inflammasome activation through ROS generation. Inhibiting the ROS or NLRP3 inflammasome significantly alleviated the damage and pyroptosis of AQP5-deficient LG epithelial cells, which could provide new insights into dry eye disease.
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Affiliation(s)
- Xin Cao
- Department of Human Anatomy, Histology and Embryology, School of Basic Medicine, Qingdao University, Qingdao, Shandong Province, China
| | - Guohu Di
- Department of Human Anatomy, Histology and Embryology, School of Basic Medicine, Qingdao University, Qingdao, Shandong Province, China,Institute of Stem Cell Regeneration Medicine, School of Basic Medicine, Qingdao University, Qingdao, China
| | - Ying Bai
- Department of Human Anatomy, Histology and Embryology, School of Basic Medicine, Qingdao University, Qingdao, Shandong Province, China
| | - Kaier Zhang
- Department of Human Anatomy, Histology and Embryology, School of Basic Medicine, Qingdao University, Qingdao, Shandong Province, China
| | - Yihui Wang
- Department of Human Anatomy, Histology and Embryology, School of Basic Medicine, Qingdao University, Qingdao, Shandong Province, China
| | - Hui Zhao
- The 971 Hospital of the Chinese People's Liberation Army Navy, Qingdao, Shandong Province, China
| | | | - Peng Chen
- Department of Human Anatomy, Histology and Embryology, School of Basic Medicine, Qingdao University, Qingdao, Shandong Province, China,Institute of Stem Cell Regeneration Medicine, School of Basic Medicine, Qingdao University, Qingdao, China
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Tran TL, Hamann S, Heegaard S. Aquaporins in Eye. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1398:203-209. [PMID: 36717496 DOI: 10.1007/978-981-19-7415-1_14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The major part of the eye consists of water. Continuous movement of water and ions between the ocular compartments and to the systemic circulation is pivotal for many physiological functions in the eye. The movement of water facilitates removal of the many metabolic products of corneal-, ciliary body-, lens-, and retinal metabolism, while maintaining transparency in the optical compartments. Transport across the corneal epithelium and endothelium maintains the corneal transparency. Also, aqueous humor is continuously secreted by the epithelia of the ciliary body and maintains the intraocular pressure. In the retina, water is transported into the vitreous body and across the retinal pigment epithelium to regulate the extracellular environment and the hydration of the retina. Aquaporins are a major contributor in the water transport throughout the eye.
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Affiliation(s)
- Thuy Linh Tran
- Department of Ophthalmology, Rigshospitalet - Glostrup, University of Copenhagen, Copenhagen, Denmark
| | - Steffen Hamann
- Department of Ophthalmology, Rigshospitalet - Glostrup, University of Copenhagen, Copenhagen, Denmark
| | - Steffen Heegaard
- Department of Ophthalmology, Rigshospitalet - Glostrup, University of Copenhagen, Copenhagen, Denmark
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Calamita G, Delporte C. Aquaporins in Glandular Secretion. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1398:225-249. [PMID: 36717498 DOI: 10.1007/978-981-19-7415-1_16] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Exocrine and endocrine glands deliver their secretory product, respectively, at the surface of the target organs or within the bloodstream. The release of their products has been shown to rely on secretory mechanisms often involving aquaporins (AQPs). This chapter will provide insight into the role of AQPs in secretory glands located within the gastrointestinal tract, including salivary glands, gastric glands, duodenal Brunner's glands, liver, gallbladder, intestinal goblets cells, and pancreas, as well and in other parts of the body, including airway submucosal glands, lacrimal glands, mammary glands, and eccrine sweat glands. The involvement of AQPs in both physiological and pathophysiological conditions will also be highlighted.
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Affiliation(s)
- Giuseppe Calamita
- Department of Biosciences, Biotechnologies and Environment, University of Bari "Aldo Moro", Bari, Italy
| | - Christine Delporte
- Laboratory of Pathophysiological and Nutritional Biochemistry, Faculty of Medicine, Université Libre de Bruxelles, Brussels, Belgium.
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Zhao X, Liu G, Yu X, Yang X, Gao W, Zhao Z, Ma T, Ma J. Ablation of AQP5 gene in mice leads to olfactory dysfunction caused by hyposecretion of Bowman's gland. Chem Senses 2023; 48:bjad030. [PMID: 37586060 DOI: 10.1093/chemse/bjad030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2022] [Indexed: 08/18/2023] Open
Abstract
Smell detection depends on nasal airflow, which can make absorption of odors to the olfactory epithelium by diffusion through the mucus layer. The odors then act on the chemo-sensitive epithelium of olfactory sensory neurons (OSNs). Therefore, any pathological changes in the olfactory area, for instance, dry nose caused by Sjögren's Syndrome (SS) may interfere with olfactory function. SS is an autoimmune disease in which aquaporin (AQP) 5 autoantibodies have been detected in the serum. However, the expression of AQP5 in olfactory mucosa and its function in olfaction is still unknown. Based on the study of the expression characteristics of AQP5 protein in the nasal mucosa, the olfaction dysfunction in AQP5 knockout (KO) mice was found by olfactory behavior analysis, which was accompanied by reduced secretion volume of Bowman's gland by using in vitro secretion measure system, and the change of acid mucin in nasal mucus layer was identified. By excluding the possibility that olfactory disturbance was caused by changes in OSNs, the result indicated that AQP5 contributes to olfactory functions by regulating the volume and composition of OE mucus layer, which is the medium for the dissolution of odor molecules. Our results indicate that AQP5 can affect the olfactory functions by regulating the water supply of BGs and the mucus layer upper the OE that can explain the olfactory loss in the patients of SS, and AQP5 KO mice might be used as an ideal model to study the olfactory dysfunction.
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Affiliation(s)
- Xinnan Zhao
- Department of Anatomy, College of Basic Medical Sciences, Dalian Medical University, Dalian, Liaoning, China
| | - Gang Liu
- Department of Anatomy, College of Basic Medical Sciences, Dalian Medical University, Dalian, Liaoning, China
| | - Xin Yu
- The High School Attached to Northeast Normal University, Changchun, Jilin, China
| | - Xiaohan Yang
- Department of Anatomy, College of Basic Medical Sciences, Dalian Medical University, Dalian, Liaoning, China
- Department of Morphology, College of Basic Medical Sciences, Dalian Medical University, Dalian, Liaoning, China
| | - Wenting Gao
- Institute of Genome Engineered Animal Models for Human Disease, National Center of Genetically Engineered Animal Models, College of Integrative Medicine, Dalian Medical University, Dalian, Liaoning, China
| | - Zinan Zhao
- Department of Biotechnology, College of Basic Medical Sciences, Dalian Medical University, Dalian, Liaoning, China
| | - Tonghui Ma
- National-Local Joint Engineering Research Center for Drug-Research and Development (R&D) of Neurodegenerative Diseases, Dalian Medical University, Dalian, Liaoning, China
- School of Medicine, Nanjing University of Chinese Medicine, Nanjing, Jiangsu, China
| | - Jianmei Ma
- Department of Anatomy, College of Basic Medical Sciences, Dalian Medical University, Dalian, Liaoning, China
- National-Local Joint Engineering Research Center for Drug-Research and Development (R&D) of Neurodegenerative Diseases, Dalian Medical University, Dalian, Liaoning, China
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Safonova TN, Pateyuk LS. [Features of water-electrolyte component of the tear fluid]. Vestn Oftalmol 2023; 139:106-113. [PMID: 36924522 DOI: 10.17116/oftalma2023139011106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/18/2023]
Abstract
Tear production is a complex multi-step process that can be arbitrarily divided into three stages: «primary» secretion by the acinar cells of the main lacrimal glands, formation of «secondary» lacrimal fluid in the ducts of the main lacrimal glands, and «tertiary» modification of the tear composition in the conjunctival sac. This article highlights mechanisms of water and electrolytes secretion in the process of tear fluid production and describes the particularities of distribution of the membrane transport proteins in the lacrimal gland and the ocular surface.
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Affiliation(s)
- T N Safonova
- Krasnov Research Institute of Eye Diseases, Moscow, Russia
| | - L S Pateyuk
- Krasnov Research Institute of Eye Diseases, Moscow, Russia
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Wood JPM, Chidlow G, Halliday LA, Casson RJ, Selva D, Sun M. Histochemical Comparison of Human and Rat Lacrimal Glands: Implications for Bio-Engineering Studies. Transl Vis Sci Technol 2022; 11:10. [PMID: 36374486 PMCID: PMC9669807 DOI: 10.1167/tvst.11.11.10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Purpose The purpose of this study was to determine whether rodent lacrimal glands (LGs) represent a suitable surrogate for human tissue in bio-engineering research, we undertook a meticulous histological and histochemical comparison of these two tissues. Methods Histological techniques and immunohistochemistry were used to compare the structure of adult human and rat LG tissues and the expression of key functional tissue elements. Results Compared with humans, the rat LG is comprised of much more densely packed acini which are devoid of an obvious central lumen. Myoepithelial, fibroblasts, dendritic cells, T cells, and putative progenitor cells are present in both tissues. However, human LG is replete with epithelium expressing cytokeratins 8 and 18, whereas rat LG epithelium does not express cytokeratin 8. Furthermore, human LG expresses aquaporins (AQPs) 1, 3, and 5, whereas rat LG expresses AQPs 1, 4, and 5. Additionally, mast cells were identified in the rat but not the human LGs and large numbers of plasma cells were detected in the human LGs but only limited numbers were present in the rat LGs. Conclusions The cellular composition of the human and rat LGs is similar, although there is a marked difference in the actual histo-architectural arrangement of the tissue. Further variances in the epithelial cytokeratin profile, in tissue expression of AQPs and in mast cell and plasma cell infiltration, may prove significant. Translational Relevance The rat LG can serve as a useful surrogate for the human equivalent, but there exist specific tissue differences meaning that caution must be observed when translating results to patients.
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Affiliation(s)
- John P. M. Wood
- Discipline of Ophthalmology & Visual Sciences, University of Adelaide, Adelaide South Australia, Australia
- South Australian Institute of Ophthalmology, Royal Adelaide Hospital, South Australia, Australia
| | - Glyn Chidlow
- Discipline of Ophthalmology & Visual Sciences, University of Adelaide, Adelaide South Australia, Australia
- South Australian Institute of Ophthalmology, Royal Adelaide Hospital, South Australia, Australia
| | - Luke A. Halliday
- Discipline of Ophthalmology & Visual Sciences, University of Adelaide, Adelaide South Australia, Australia
- South Australian Institute of Ophthalmology, Royal Adelaide Hospital, South Australia, Australia
| | - Robert J. Casson
- Discipline of Ophthalmology & Visual Sciences, University of Adelaide, Adelaide South Australia, Australia
- South Australian Institute of Ophthalmology, Royal Adelaide Hospital, South Australia, Australia
| | - Dinesh Selva
- Discipline of Ophthalmology & Visual Sciences, University of Adelaide, Adelaide South Australia, Australia
- South Australian Institute of Ophthalmology, Royal Adelaide Hospital, South Australia, Australia
| | - Michelle Sun
- Discipline of Ophthalmology & Visual Sciences, University of Adelaide, Adelaide South Australia, Australia
- South Australian Institute of Ophthalmology, Royal Adelaide Hospital, South Australia, Australia
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Aquaporins 8 and 9 as Possible Markers for Adult Murine Lacrimal Gland Cells. BIOMED RESEARCH INTERNATIONAL 2021; 2021:6888494. [PMID: 34540996 PMCID: PMC8445729 DOI: 10.1155/2021/6888494] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 08/10/2021] [Accepted: 08/25/2021] [Indexed: 11/17/2022]
Abstract
Aquaporins (AQPs) are proteins that selectively transport water across the cell membrane. Although AQPs play important roles in secretion in the lacrimal gland, the expression and localization of AQPs have not been clarified yet. In the current study, we investigated the expression pattern of AQP family members in the murine lacrimal gland during development. Lacrimal gland tissues were harvested from E13.5 and E17.5 murine embryos and from mice 8 weeks of age (adults). Corneal and conjunctival tissues from the latter served as controls. Total RNA was isolated and analyzed for the expression of AQP family members using qPCR. The localization of AQPs in the adult lacrimal gland in adult murine lacrimal glands was also analyzed. Expression of Aqp8 and Aqp9 mRNAs was detected in the adult lacrimal gland but not in the cornea, conjunctiva, or fetal lacrimal gland. AQP8 and AQP9 and α-SMA partially colocalized around the basal regions of the acinar unit. The levels of Aqp3 mRNAs and protein were much lower in the adult lacrimal gland but were readily detected in the adult cornea and conjunctiva. Our study suggests that AQP8 and AQP9 may serve as markers for adult murine lacrimal gland, ductal, and myoepithelial cells.
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Tang S, Di G, Hu S, Liu Y, Dai Y, Chen P. AQP5 regulates vimentin expression via miR-124-3p.1 to protect lens transparency. Exp Eye Res 2021; 205:108485. [PMID: 33582182 DOI: 10.1016/j.exer.2021.108485] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 01/27/2021] [Accepted: 01/29/2021] [Indexed: 12/18/2022]
Abstract
The pathogenesis of congenital cataract (CC), a major disease associated with blindness in infants, is complex and diverse. Aquaporin 5 (AQP5) represents an essential membrane water channel. In the present study, whole exome sequencing revealed a novel heterozygous missense mutation of AQP5 (c.152 T > C, p. L51P) in the four generations of the autosomal dominant CC (adCC) family. By constructing a mouse model of AQP5 knockout (KO) using the CRISPR/Cas9 technology, we observed that the lens of AQP5-KO mice showed mild opacity at approximately six months of age. miR-124-3p.1 expression was identified to be downregulated in the lens of AQP5-KO mice as evidenced by qRT-PCR analysis. A dual luciferase reporter assay confirmed that vimentin was a target gene of miR-124-3p.1. Organ-cultured AQP5-KO mouse lenses were showed increased opacity compared to those of WT mice, and vimentin expression was upregulated as determined by RT-PCR, western blotting, and immunofluorescence staining. After miR-124-3p.1 agomir was added, the lens opacity in WT mice and AQP5-KO mice decreased, accompanied by the downregulation of vimentin. AQP5-L51P increased vimentin expression of in human lens epithelial cells. Therefore, a missense mutation in AQP5 (c.152 T > C, p. L51P) was associated with adCC, and AQP5 could participate in the maintenance of lens transparency by regulating vimentin expression via miR-124-3p.1.
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Affiliation(s)
- Suzhen Tang
- Department of Human Anatomy, Histology and Embryology, School of Basic Medicine, Qingdao University, Qingdao, 266071, Shandong Province, China
| | - Guohu Di
- Department of Human Anatomy, Histology and Embryology, School of Basic Medicine, Qingdao University, Qingdao, 266071, Shandong Province, China; Institute of Stem Cell Regeneration Medicine, School of Basic Medicine, Qingdao University, Qingdao, 266071, China
| | - Shaohua Hu
- Department of Human Anatomy, Histology and Embryology, School of Basic Medicine, Qingdao University, Qingdao, 266071, Shandong Province, China
| | - Yaning Liu
- Department of Human Anatomy, Histology and Embryology, School of Basic Medicine, Qingdao University, Qingdao, 266071, Shandong Province, China
| | - Yunhai Dai
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Shandong Eye Institute, Shandong First Medical University & Shandong Academy of Medical Sciences, Qingdao, China.
| | - Peng Chen
- Department of Human Anatomy, Histology and Embryology, School of Basic Medicine, Qingdao University, Qingdao, 266071, Shandong Province, China; Institute of Stem Cell Regeneration Medicine, School of Basic Medicine, Qingdao University, Qingdao, 266071, China.
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Tóth-Molnár E, Ding C. New insight into lacrimal gland function: Role of the duct epithelium in tear secretion. Ocul Surf 2020; 18:595-603. [DOI: 10.1016/j.jtos.2020.07.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Revised: 06/21/2020] [Accepted: 07/07/2020] [Indexed: 02/08/2023]
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N-Glycanase 1 Transcriptionally Regulates Aquaporins Independent of Its Enzymatic Activity. Cell Rep 2020; 29:4620-4631.e4. [PMID: 31875565 DOI: 10.1016/j.celrep.2019.11.097] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Revised: 10/22/2019] [Accepted: 11/22/2019] [Indexed: 11/21/2022] Open
Abstract
Patients with pathogenic mutations in NGLY1 cannot make tears and have global developmental delay and liver dysfunction. Traditionally, NGLY1 cleaves intact N-glycans from misfolded, retrotranslocated glycoproteins before proteasomal degradation. We demonstrate that Ngly1-null mouse embryonic fibroblasts, NGLY1 knockout human cells, and patient fibroblasts are resistant to hypotonic lysis. Ngly1-deficient mouse embryonic fibroblasts swell slower and have reduced aquaporin1 mRNA and protein expression. Ngly1 knockdown and overexpression confirms that Ngly1 regulates aquaporin1 and hypotonic cell lysis. Patient fibroblasts and NGLY1 knockout cells show reduced aquaporin11 mRNA, supporting NGLY1 as regulating expression of multiple aquaporins across species. Complementing Ngly1-deficient cells with catalytically inactive NGLY1 (p.Cys309Ala) restores normal hypotonic lysis and aquaporin1 protein. We show that transcription factors Atf1/Creb1 regulate aquaporin1 and that the Atf1/Creb1 signaling pathway is disrupted in Ngly1-deficient mouse embryonic fibroblasts. These results identify a non-enzymatic, regulatory function of NGLY1 in aquaporin transcription, possibly related to alacrima and neurological symptoms.
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Petrova RS, Bavana N, Zhao R, Schey KL, Donaldson PJ. Changes to Zonular Tension Alters the Subcellular Distribution of AQP5 in Regions of Influx and Efflux of Water in the Rat Lens. Invest Ophthalmol Vis Sci 2020; 61:36. [PMID: 32945844 PMCID: PMC7509773 DOI: 10.1167/iovs.61.11.36] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Accepted: 08/20/2020] [Indexed: 11/24/2022] Open
Abstract
Purpose The lens uses circulating fluxes of ions and water that enter the lens at both poles and exit at the equator to maintain its optical properties. We have mapped the subcellular distribution of the lens aquaporins (AQP0, AQP1, and AQP5) in these water influx and efflux zones and investigated how their membrane location is affected by changes in tension applied to the lens by the zonules. Methods Immunohistochemistry using AQP antibodies was performed on axial sections obtained from rat lenses that had been removed from the eye and then fixed or were fixed in situ to maintain zonular tension. Zonular tension was pharmacologically modulated by applying either tropicamide (increased) or pilocarpine (decreased). AQP labeling was visualized using confocal microscopy. Results Modulation of zonular tension had no effect on AQP1 or AQP0 labeling in either the water efflux or influx zones. In contrast, AQP5 labeling changed from membranous to cytoplasmic in response to both mechanical and pharmacologically induced reductions in zonular tension in both the efflux zone and anterior (but not posterior) influx zone associated with the lens sutures. Conclusions Altering zonular tension dynamically regulates the membrane trafficking of AQP5 in the efflux and anterior influx zones to potentially change the magnitude of circulating water fluxes in the lens.
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Affiliation(s)
- Rosica S. Petrova
- Department of Physiology, School of Medical Sciences, New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand
| | - Nandini Bavana
- Department of Physiology, School of Medical Sciences, New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand
| | - Rusin Zhao
- Department of Physiology, School of Medical Sciences, New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand
| | - Kevin L. Schey
- Mass Spectrometry Research Center, Vanderbilt University, Nashville, Tennessee, United States
| | - Paul J. Donaldson
- Department of Physiology, School of Medical Sciences, New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand
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Wang D, Zhao H, Li B, Sun Y, Wei DH. Mechanism of cAMP-PKA Signaling Pathway Mediated by Shaoyao Gancao Decoction (芍药甘草汤) on Regulation of Aquaporin 5 and Muscarinic Receptor 3 Levels in Sjögren’s Syndrome. Chin J Integr Med 2020; 26:502-509. [DOI: 10.1007/s11655-020-3205-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/14/2019] [Indexed: 12/14/2022]
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Lamagna B, Ciaramella P, Lamagna F, Di Loria A, Brunetti A, Pelagalli A. Aquaporin 1 (AQP1) Expression in Healthy Dog Tears. Animals (Basel) 2020; 10:ani10050820. [PMID: 32397372 PMCID: PMC7278581 DOI: 10.3390/ani10050820] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 05/06/2020] [Accepted: 05/07/2020] [Indexed: 12/28/2022] Open
Abstract
Simple Summary The characterisation of tear proteins is very important for scientists and clinicians, as it enhances their understanding of ocular physiological phenomena that sometimes evolve into diseases. Recently, ophthalmic research has been focused on aquaporins (AQPs), a family of water channel proteins that are largely ubiquitous in body tissues and are known for their role in water and small solute transport across cell membranes. Based on AQPs’ presumable role in the eye, the aim of the present study was to investigate the expression of aquaporin-1 (AQP1) by Western blot analysis in canine eye tears. To this end, we collected tears from both eyes of 15 healthy dogs by employing two tear collection methods: Schirmer tear strips (STS) and ophthalmic sponges (OS). Moreover, ocular parameters such as Schirmer tear test 1 (STT 1), intraocular pressure (IOP), and tear film break up time (BUT) were measured, and fluorescein and lissamine green staining were performed to uncover possible correlations among the aforementioned parameters. Our results showed that the expression of AQP1 in tears collected by both methods and expressed as multiple bands (measured by densitometry) was higher for the tears collected by OS than for those collected by STS. This work forms the basis of future studies aiming to understand and establish the involvement of AQPs in the production and secretion of tears. Abstract Aquaporins (AQPs) are a family of thirteen membrane proteins that play an essential role in the transport of fluids across the cell plasma membrane. Recently, the expression of AQPs in different ocular tissues and their involvement in the pathophysiology of eye diseases, have garnered attention. Considering that literature on AQP expression in the lacrimal glands and their secretion is scarce, we aimed to characterise AQP1 expression in the tears of healthy dogs using two tear collection methods (Schirmer tear strips (STS) and ophthalmic sponges (OS)). Fifteen healthy dogs, free of ophthalmic diseases, were included in the study. Tear collection was performed by using STS in one eye and OS in the other. After the extraction of proteins from the tears, the expression of AQP1 was analysed by Western blotting. AQP1 was expressed as a band of 28 kDa. In addition, differences were observed in the expression of AQP1 and in the correlation between tear volume and protein concentration, in tears collected by the two different methods. Our results suggest that AQP1 has a specific role in tear secretion; further research is required to assess its particular role in the function of the ocular surface in eye physiology and pathology.
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Affiliation(s)
- Barbara Lamagna
- Department of Veterinary Medicine and Animal Production, University of Naples Federico II, 80137 Naples, Italy; (B.L.); (P.C.); (F.L.); (A.D.L.)
| | - Paolo Ciaramella
- Department of Veterinary Medicine and Animal Production, University of Naples Federico II, 80137 Naples, Italy; (B.L.); (P.C.); (F.L.); (A.D.L.)
| | - Francesco Lamagna
- Department of Veterinary Medicine and Animal Production, University of Naples Federico II, 80137 Naples, Italy; (B.L.); (P.C.); (F.L.); (A.D.L.)
| | - Antonio Di Loria
- Department of Veterinary Medicine and Animal Production, University of Naples Federico II, 80137 Naples, Italy; (B.L.); (P.C.); (F.L.); (A.D.L.)
| | - Arturo Brunetti
- Department of Advanced Biomedical Sciences, University of Naples Federico II, 80131 Naples, Italy;
| | - Alessandra Pelagalli
- Department of Advanced Biomedical Sciences, University of Naples Federico II, 80131 Naples, Italy;
- Institute of Biostructures and Bioimaging (IBB), National Research Council (CNR), 80131 Naples, Italy
- Correspondence:
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Physiological and pathological impact of AQP1 knockout in mice. Biosci Rep 2019; 39:BSR20182303. [PMID: 31023968 PMCID: PMC6522737 DOI: 10.1042/bsr20182303] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2018] [Revised: 04/21/2019] [Accepted: 04/24/2019] [Indexed: 01/04/2023] Open
Abstract
Aquaporin 1 (AQP1) is a glycoprotein responsible for water passive transport quickly across biological membrane. Here, we reviewed the structural and functional impacts of AQP1 knockout (AQP1-KO) in animal or cell culture models. AQP1 gene deletion can cause a large number of abnormalities including the disturbance in epithelial fluid secretion, polyhydramnios, deficiency of urinary concentrating function, and impairment of pain perception. AQP1-KO mice also displayed aberrations of cardiovascular, gastrointestinal and hepatobiliary, and kidney functions as well as placenta and embryo development. Moreover, AQP1-KO perturbed tumor angiogenesis and led to reduced brain injury upon trauma. On the cellular level, AQP1-KO caused neuroinflammation, aberrant cell proliferation and migration, and macrophages infiltration. Mechanistic studies confirmed that AQP1 gene products regulate the secretory function and participated in balancing the osmotic water flux across the peritoneal membrane. The available data indicated that AQP1 might serve as a potential target for developing novel therapeutic approaches against diverse human diseases.
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Reduced Expression of VAMP8 in Lacrimal Gland Affected by Chronic Graft-versus-Host Disease. J Ophthalmol 2017; 2017:1639012. [PMID: 29098081 PMCID: PMC5643041 DOI: 10.1155/2017/1639012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Accepted: 08/01/2017] [Indexed: 01/06/2023] Open
Abstract
Purpose To investigate whether the SNARE protein vesicle-associated membrane protein 8 (VAMP8) was implicated in the development of chronic ocular graft-versus-host disease (GVHD). Methods Firstly, the chronic GVHD (cGVHD) and Sjögren's syndrome (SS)-impaired lacrimal gland (LG) tissue sections from humans for diagnostic purpose were evaluated for VAMP8 expression by histopathology and immunohistochemistry. Next, serial changes of tear secretion and VAMP8 expression at both protein and mRNA level of LG in an animal cGVHD model compared with the syngeneic control. Results Decreased VAMP 8 expression in the cGVHD-affected human LG was detected in comparison with SS-affected LG. Tear secretion in the murine cGVHD model was significantly reduced compared with that in the syngeneic controls 8 weeks after BMT. Protein expression of VAMP8 in the cGVHD-affected LG in murine cGVHD was decreased in comparison with that in the controls. Gene expression of VAMP8 in the cGVHD-affected murine LG was significantly less than that in the syngeneic control 3 weeks after BMT. Conclusions Our results suggested that expression of VAMP8 in the cGVHD-affected LG was decreased and accordingly tear secretion in cGVHD was reduced. Collectively, the reduction of VAMP8 expression in the cGVHD-affected LG can be involved in the pathogenic processes of cGVHD-induced dry eye disease.
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Abstract
Aquaporins (AQPs ) are expressed in most exocrine and endocrine secretory glands. Consequently, summarizing the expression and functions of AQPs in secretory glands represents a daunting task considering the important number of glands present in the body, as well as the number of mammalian AQPs - thirteen. The roles played by AQPs in secretory processes have been investigated in many secretory glands. However, despite considerable research, additional studies are clearly needed to pursue our understanding of the role played by AQPs in secretory processes. This book chapter will focus on summarizing the current knowledge on AQPs expression and function in the gastrointestinal tract , including salivary glands, gastric glands, Duodenal Brunner's gland, liver and gallbladder, intestinal goblets cells, exocrine and endocrine pancreas, as well as few other secretory glands including airway submucosal glands, lacrimal glands, mammary glands and eccrine sweat glands.
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Affiliation(s)
- Christine Delporte
- Laboratory of Pathophysiological and Nutritional Biochemistry, Faculty of Medicine, Université Libre de Bruxelles, Brussels, Belgium.
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Sutka M, Amodeo G, Ozu M. Plant and animal aquaporins crosstalk: what can be revealed from distinct perspectives. Biophys Rev 2017; 9:545-562. [PMID: 28871493 DOI: 10.1007/s12551-017-0313-3] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Accepted: 08/02/2017] [Indexed: 01/03/2023] Open
Abstract
Aquaporins (AQPs) can be revisited from a distinct and complementary perspective: the outcome from analyzing them from both plant and animal studies. (1) The approach in the study. Diversity found in both kingdoms contrasts with the limited number of crystal structures determined within each group. While the structure of almost half of mammal AQPs was resolved, only a few were resolved in plants. Strikingly, the animal structures resolved are mainly derived from the AQP2-lineage, due to their important roles in water homeostasis regulation in humans. The difference could be attributed to the approach: relevance in animal research is emphasized on pathology and in consequence drug screening that can lead to potential inhibitors, enhancers and/or regulators. By contrast, studies on plants have been mainly focused on the physiological role that AQPs play in growth, development and stress tolerance. (2) The transport capacity. Besides the well-described AQPs with high water transport capacity, large amount of evidence confirms that certain plant AQPs can carry a large list of small solutes. So far, animal AQP list is more restricted. In both kingdoms, there is a great amount of evidence on gas transport, although there is still an unsolved controversy around gas translocation as well as the role of the central pore of the tetramer. (3) More roles than expected. We found it remarkable that the view of AQPs as specific channels has evolved first toward simple transporters to molecules that can experience conformational changes triggered by biochemical and/or mechanical signals, turning them also into signaling components and/or behave as osmosensor molecules.
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Affiliation(s)
- Moira Sutka
- Departamento de Biodiversidad y Biología Experimental, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires e Instituto de Biodiversidad y Biología Experimental, Universidad de Buenos Aires y Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina
| | - Gabriela Amodeo
- Departamento de Biodiversidad y Biología Experimental, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires e Instituto de Biodiversidad y Biología Experimental, Universidad de Buenos Aires y Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina.
| | - Marcelo Ozu
- Departamento de Biodiversidad y Biología Experimental, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires e Instituto de Biodiversidad y Biología Experimental, Universidad de Buenos Aires y Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina.
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Xu C, Jiang L, Zou Y, Xing J, Sun H, Zhu B, Zhang H, Wang J, Zhang J. Involvement of water channel Aquaporin 5 in H 2S-induced pulmonary edema. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2017; 49:202-211. [PMID: 28088675 DOI: 10.1016/j.etap.2016.12.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2016] [Revised: 12/23/2016] [Accepted: 12/27/2016] [Indexed: 06/06/2023]
Abstract
Acute exposure to hydrogen sulfide (H2S) poses a significant threat to life, and the lung is one of the primary target organs of H2S. However, the mechanisms involved in H2S-induced acute pulmonary edema are poorly understood. This study aims to investigate the effects of H2S on the expression of water channel aquaporin 5 (AQP5) and to elucidate the signaling pathways involved in AQP5 regulation. In an in vivo study, C57BL6 mice were exposed to sub-lethal concentrations of inhaled H2S, and histological injury of the lungs and ultrastructure injury of the epithelial cells were evaluated. With real-time PCR and western blot assays, we found that H2S exposure contributed to a significant decrease in AQP5 expression both in murine lung tissue and the A549 cell line, and the ERK1/2 and p38 MAPK signaling pathways were demonstrated to be implicated in AQP5 regulation. Therefore, adjusting AQP5 protein levels could be considered a therapeutic strategy for the treatment of APE induced by H2S and other hazardous gases.
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Affiliation(s)
- Chunyang Xu
- Department of Emergency Medicine, The First Affiliated Hospital of Nanjing Medical University, 300 Guangzhou Road, Nanjing, Jiangsu, 210029, China
| | - Lei Jiang
- Department of Emergency Medicine, The First Affiliated Hospital of Nanjing Medical University, 300 Guangzhou Road, Nanjing, Jiangsu, 210029, China
| | - Yuxia Zou
- Key Lab of Modern Toxicology (NJMU), Ministry of Education. Department of Toxicology, School of Public Health, Nanjing Medical University, 818 Tianyuan East Road, Nanjing, Jiangsu, 211166, China
| | - Jingjing Xing
- Department of Emergency Medicine, The First Affiliated Hospital of Nanjing Medical University, 300 Guangzhou Road, Nanjing, Jiangsu, 210029, China
| | - Hao Sun
- Department of Emergency Medicine, The First Affiliated Hospital of Nanjing Medical University, 300 Guangzhou Road, Nanjing, Jiangsu, 210029, China
| | - Baoli Zhu
- Department of Occupational Disease Prophylactic-Therapeutic Institution, Jiangsu Provincial Center for Disease Prevention and Control, 122 Heban Cun, Nanjing, Jiangsu, 210028, China
| | - Hengdong Zhang
- Department of Occupational Disease Prophylactic-Therapeutic Institution, Jiangsu Provincial Center for Disease Prevention and Control, 122 Heban Cun, Nanjing, Jiangsu, 210028, China
| | - Jun Wang
- Key Lab of Modern Toxicology (NJMU), Ministry of Education. Department of Toxicology, School of Public Health, Nanjing Medical University, 818 Tianyuan East Road, Nanjing, Jiangsu, 211166, China.
| | - Jinsong Zhang
- Department of Emergency Medicine, The First Affiliated Hospital of Nanjing Medical University, 300 Guangzhou Road, Nanjing, Jiangsu, 210029, China.
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Warcoin E, Clouzeau C, Brignole-Baudouin F, Baudouin C. Hyperosmolarité : effets intracellulaires et implication dans la sécheresse oculaire. J Fr Ophtalmol 2016; 39:641-51. [DOI: 10.1016/j.jfo.2016.07.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Revised: 07/27/2016] [Accepted: 07/27/2016] [Indexed: 11/26/2022]
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Nakamachi T, Ohtaki H, Seki T, Yofu S, Kagami N, Hashimoto H, Shintani N, Baba A, Mark L, Lanekoff I, Kiss P, Farkas J, Reglodi D, Shioda S. PACAP suppresses dry eye signs by stimulating tear secretion. Nat Commun 2016; 7:12034. [PMID: 27345595 PMCID: PMC4931240 DOI: 10.1038/ncomms12034] [Citation(s) in RCA: 75] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Accepted: 05/22/2016] [Indexed: 01/05/2023] Open
Abstract
Dry eye syndrome is caused by a reduction in the volume or quality of tears. Here, we show that pituitary adenylate cyclase-activating polypeptide (PACAP)-null mice develop dry eye-like symptoms such as corneal keratinization and tear reduction. PACAP immunoreactivity is co-localized with a neuronal marker, and PACAP receptor (PAC1-R) immunoreactivity is observed in mouse infraorbital lacrimal gland acinar cells. PACAP eye drops stimulate tear secretion and increase cAMP and phosphorylated (p)-protein kinase A levels in the infraorbital lacrimal glands that could be inhibited by pre-treatment with a PAC1-R antagonist or an adenylate cyclase inhibitor. Moreover, these eye drops suppress corneal keratinization in PACAP-null mice. PACAP eye drops increase aquaporin 5 (AQP5) levels in the membrane and pAQP5 levels in the infraorbital lacrimal glands. AQP5 siRNA treatment of the infraorbital lacrimal gland attenuates PACAP-induced tear secretion. Based on these results, PACAP might be clinically useful to treat dry eye disorder.
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Affiliation(s)
- Tomoya Nakamachi
- Laboratory of Regulatory Biology, Graduate School of Science and Engineering, University of Toyama, 3190-Gofuku, Toyama-shi, Toyama 930-8555, Japan.,Department of Anatomy, Showa University School of Medicine, Shinagawa-Ku, Tokyo 142-8555, Japan
| | - Hirokazu Ohtaki
- Department of Anatomy, Showa University School of Medicine, Shinagawa-Ku, Tokyo 142-8555, Japan
| | - Tamotsu Seki
- Department of Anatomy, Showa University School of Medicine, Shinagawa-Ku, Tokyo 142-8555, Japan
| | - Sachiko Yofu
- Department of Anatomy, Showa University School of Medicine, Shinagawa-Ku, Tokyo 142-8555, Japan
| | - Nobuyuki Kagami
- Department of Anatomy, Showa University School of Medicine, Shinagawa-Ku, Tokyo 142-8555, Japan
| | - Hitoshi Hashimoto
- Laboratory of Molecular Neuropharmacology, Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871, Japan.,iPS Cell-based Research Project on Brain Neuropharmacology and Toxicology, Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871, Japan.,Molecular Research Center for Children's Mental Development, United Graduate School of Child Development, Osaka University, Kanazawa University, Hamamatsu University School of Medicine, Chiba University and University of Fukui, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Norihito Shintani
- Laboratory of Molecular Neuropharmacology, Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Akemichi Baba
- Hyogo University of Health Sciences, 1-3-6 Minatojima, Chuo-ku, Kobe, Hyogo 650-8530, Japan
| | - Laszlo Mark
- Department of Analytical Biochemistry, Institute of Biochemistry and Medical Chemistry, Medical School, University of Pécs, Szigeti u 12, Pécs 7624, Hungary.,Imaging Center for Life and Material Sciences, University of Pécs, Szigeti u 12, Pécs 7624, Hungary.,János Szentágothai Research Center, University of Pécs, Szigeti u 12, Pécs 7624, Hungary.,PTE-MTA Human Reproduction Research Group, Szigeti u 12, Pécs 7624, Hungary
| | - Ingela Lanekoff
- Department of Chemistry-BMC, Uppsala University, PO Box 599, Uppsala 751 24, Sweden
| | - Peter Kiss
- Department of Anatomy, MTA-PTE PACAP Lendulet Research Group, Centre for Neuroscience, University of Pécs, Szigeti u 12, Pécs 7624, Hungary
| | - Jozsef Farkas
- Department of Anatomy, Showa University School of Medicine, Shinagawa-Ku, Tokyo 142-8555, Japan.,Department of Anatomy, MTA-PTE PACAP Lendulet Research Group, Centre for Neuroscience, University of Pécs, Szigeti u 12, Pécs 7624, Hungary
| | - Dora Reglodi
- Department of Anatomy, MTA-PTE PACAP Lendulet Research Group, Centre for Neuroscience, University of Pécs, Szigeti u 12, Pécs 7624, Hungary
| | - Seiji Shioda
- Innovative Drug Discovery, Global Research Center for Innovative Life Science, Hoshi University, 4-41 Ebara 2-chome, Shinagawa-ku, Tokyo 142-8501, Japan
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Du Q, Lin M, Yang JH, Chen JF, Tu YR. Overexpression of AQP5 Was Detected in Axillary Sweat Glands of Primary Focal Hyperhidrosis Patients. Dermatology 2016; 232:150-5. [DOI: 10.1159/000444081] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2015] [Accepted: 01/11/2016] [Indexed: 11/19/2022] Open
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Papadopoulos MC, Saadoun S. Key roles of aquaporins in tumor biology. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2014; 1848:2576-83. [PMID: 25204262 DOI: 10.1016/j.bbamem.2014.09.001] [Citation(s) in RCA: 148] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2014] [Revised: 08/25/2014] [Accepted: 09/01/2014] [Indexed: 12/13/2022]
Abstract
Aquaporins are protein channels that facilitate the flow of water across plasma cell membranes in response to osmotic gradients. This review summarizes the evidence that aquaporins play key roles in tumor biology including tumor-associated edema, tumor cell migration, tumor proliferation and tumor angiogenesis. Aquaporin inhibitors may thus be a novel class of anti-tumor agents. However, attempts to produce small molecule aquaporin inhibitors have been largely unsuccessful. Recently, monoclonal human IgG antibodies against extracellular aquaporin-4 domains have become available and could be engineered to kill aquaporin-4 over-expressing cells in the malignant brain tumor glioblastoma. We conclude this review by discussing future directions in aquaporin tumor research. This article is part of a Special Issue entitled: Membrane channels and transporters in cancers.
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Affiliation(s)
| | - Samira Saadoun
- Academic Neurosurgery Unit, St. George's, University of London, London SW17 0RE, UK.
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Abstract
The aquaporins (AQPs) are a family of small, integral membrane proteins that facilitate water transport across the plasma membranes of cells in response to osmotic gradients. Data from knockout mice support the involvement of AQPs in epithelial fluid secretion, cell migration, brain oedema and adipocyte metabolism, which suggests that modulation of AQP function or expression could have therapeutic potential in oedema, cancer, obesity, brain injury, glaucoma and several other conditions. Moreover, loss-of-function mutations in human AQPs cause congenital cataracts (AQP0) and nephrogenic diabetes insipidus (AQP2), and autoantibodies against AQP4 cause the autoimmune demyelinating disease neuromyelitis optica. Although some potential AQP modulators have been identified, challenges associated with the development of better modulators include the druggability of the target and the suitability of the assay methods used to identify modulators.
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She J, Bi J, Tong L, Song Y, Bai C. New insights of aquaporin 5 in the pathogenesis of high altitude pulmonary edema. Diagn Pathol 2013; 8:193. [PMID: 24274330 PMCID: PMC3937216 DOI: 10.1186/1746-1596-8-193] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2013] [Accepted: 10/26/2013] [Indexed: 11/28/2022] Open
Abstract
Background High altitude pulmonary edema (HAPE) affects individuals and is characterized by alveolar flooding with protein-rich edema as a consequence of blood-gas barrier disruption. In this study, we hypothesized that aquaporin 5 (AQP5) which is one kind of water channels may play a role in preservation of alveolar epithelial barrier integrity in high altitude pulmonary edema (HAPE). Methods Therefore, we established a model in Wildtype mice and AQP5 −/− mice were assingned to normoxic rest (NR), hypoxic rest (HR) and hypoxic exercise (HE) group. Mice were produced by training to walk at treadmill for exercising and chamber pressure was reduced to simulate climbing an altitude of 5000 m for 48 hours. Studies using BAL in HAPE mice to demonstrated that edema is caused leakage of albumin proteins and red cells across the alveolarcapillary barrier in the absence of any evidence of inflammation. Results In this study, the Lung wet/dry weight ratio and broncholalveolar lavage protein concentrations were slightly increased in HE AQP5 −/− mice compared to wildtype mice. And histologic evidence of hemorrhagic pulmonary edema was distinctly shown in HE group. The lung Evan’s blue permeability of HE group was showed slightly increased compare to the wildtype groups, and HR group was showed a medium situation from normal to HAPE development compared with NR and HE group. Conclusions Deletion of AQP5 slightly increased lung edema and lung injury compared to wildtype mice during HAPE development, which suggested that the AQP5 plays an important role in HAPE formation induced by high altitude simulation.
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Affiliation(s)
| | | | | | | | - Chunxue Bai
- Department of Pulmonary Medicine, Zhongshan Hospital, Fudan University, NO,180 Fenglin Road, Shanghai 200032, China.
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Schey KL, Wang Z, L Wenke J, Qi Y. Aquaporins in the eye: expression, function, and roles in ocular disease. Biochim Biophys Acta Gen Subj 2013; 1840:1513-23. [PMID: 24184915 DOI: 10.1016/j.bbagen.2013.10.037] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2013] [Revised: 10/22/2013] [Accepted: 10/23/2013] [Indexed: 12/13/2022]
Abstract
BACKGROUND All thirteen known mammalian aquaporins have been detected in the eye. Moreover, aquaporins have been identified as playing essential roles in ocular functions ranging from maintenance of lens and corneal transparency to production of aqueous humor to maintenance of cellular homeostasis and regulation of signal transduction in the retina. SCOPE OF REVIEW This review summarizes the expression and known functions of ocular aquaporins and discusses their known and potential roles in ocular diseases. MAJOR CONCLUSIONS Aquaporins play essential roles in all ocular tissues. Remarkably, not all aquaporin function as a water permeable channel and the functions of many aquaporins in ocular tissues remain unknown. Given their vital roles in maintaining ocular function and their roles in disease, aquaporins represent potential targets for future therapeutic development. GENERAL SIGNIFICANCE Since aquaporins play key roles in ocular physiology, an understanding of these functions is important to improving ocular health and treating diseases of the eye. It is likely that future therapies for ocular diseases will rely on modulation of aquaporin expression and/or function. This article is part of a Special Issue entitled Aquaporins.
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Affiliation(s)
- Kevin L Schey
- Department of Biochemistry, Vanderbilt School of Medicine, Vanderbilt University, Nashville, TN 37232, USA.
| | - Zhen Wang
- Department of Biochemistry, Vanderbilt School of Medicine, Vanderbilt University, Nashville, TN 37232, USA
| | - Jamie L Wenke
- Department of Biochemistry, Vanderbilt School of Medicine, Vanderbilt University, Nashville, TN 37232, USA
| | - Ying Qi
- Department of Biochemistry, Vanderbilt School of Medicine, Vanderbilt University, Nashville, TN 37232, USA
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Abstract
Aquaporins are a group of proteins with high-selective permeability for water. A subgroup called aquaglyceroporins is also permeable to glycerol, urea and a few other solutes. Aquaporin function has mainly been studied in the brain, kidney, glands and skeletal muscle, while the information about aquaporins in the heart is still scarce. The current review explores the recent advances in this field, bringing aquaporins into focus in the context of myocardial ischemia, reperfusion, and blood osmolarity disturbances. Since the amount of data on aquaporins in the heart is still limited, examples and comparisons from better-studied areas of aquaporin biology have been used. The human heart expresses aquaporin-1, -3, -4 and -7 at the protein level. The potential roles of aquaporins in the heart are discussed, and some general phenomena that the myocardial aquaporins share with aquaporins in other organs are elaborated. Cardiac aquaporin-1 is mostly distributed in the microvasculature. Its main role is transcellular water flux across the endothelial membranes. Aquaporin-4 is expressed in myocytes, both in cardiac and in skeletal muscle. In addition to water flux, its function is connected to the calcium signaling machinery. It may play a role in ischemia-reperfusion injury. Aquaglyceroporins, especially aquaporin-7, may serve as a novel pathway for nutrient delivery into the heart. They also mediate toxicity of various poisons. Aquaporins cannot influence permeability by gating, therefore, their function is regulated by changes of expression-on the levels of transcription, translation (by microRNAs), post-translational modification, membrane trafficking, ubiquitination and subsequent degradation. Studies using mice genetically deficient for aquaporins have shown rather modest changes in the heart. However, they might still prove to be attractive targets for therapy directed to reduce myocardial edema and injury caused by ischemia and reperfusion.
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Kosenda K, Ichii O, Otsuka S, Hashimoto Y, Kon Y. BXSB/MpJ-Yaa mice develop autoimmune dacryoadenitis with the appearance of inflammatory cell marker messenger RNAs in the lacrimal fluid. Clin Exp Ophthalmol 2013; 41:788-97. [PMID: 23433092 DOI: 10.1111/ceo.12083] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2012] [Accepted: 01/22/2013] [Indexed: 11/30/2022]
Abstract
BACKGROUND Dacryoadenitis is characteristic of an autoimmune exocrinopathy, e.g. Sjögren syndrome. We pathologically examined the lacrimal glands of autoimmune-prone BXSB/MpJ-Yaa mice for the appearance of pathological signs of dacryoadenitis progression in autoimmune dacryoadenitis models, particularly focusing on messenger RNAs in the lacrimal fluid. METHODS The lacrimal glands of the BXSB/MpJ-Yaa and C57BL/6 mice were histopathologically analyzed in parallel with the evaluation of lacrimation and messenger RNA expression of water channels (Aqp3, Aqp4 and Aqp5). In addition, autoimmune model mice (MRL/MpJ-lpr/lpr and NZB/NZWF1) were used for evaluating cell infiltration and detecting inflammatory cell marker messenger RNAs (Cd68, Ptprc and Cd3e) in the lacrimal fluids by polymerase chain reaction-based methods. RESULTS B-cell predominant lymphocytic infiltrations and the destruction of acini were observed in the lacrimal glands of BXSB/MpJ-Yaa mice. There was no significant difference in the quantity of lacrimal fluid between the BXSB/MpJ-Yaa and C57BL/6 mice. In the BXSB/MpJ-Yaa mice, Aqp3 expression increased significantly with the cell infiltration score, whereas expression of Aqp4 and Aqp5 tended to decrease. Aqp3 expression increased significantly with the cell infiltration score in BXSB/MpJ-Yaa mice. Among inflammatory cell markers, Cd68 was more frequently detected in the lacrimal fluid of the BXSB/MpJ-Yaa, MRL/MpJ-lpr/lpr and NZB/NZWF1 mice than in that of the C57BL/6 mice. CONCLUSION BXSB/MpJ-Yaa mice clearly developed autoimmune dacryoadenitis. The altered expression of water channels in lacrimal glands might be associated with the preservation of lacrimal fluid excretion in BXSB/MpJ-Yaa mice. The detection of inflammatory cell markers in lacrimal fluid could be used as a diagnostic marker for autoimmune dacryoadenitis.
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Affiliation(s)
- Keigo Kosenda
- Laboratory of Anatomy, Department of Biomedical Sciences, Hokkaido University, Sapporo, Japan
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Immunolocalization and translocation of aquaporin-5 water channel in sweat glands. J Dermatol Sci 2013; 70:26-33. [DOI: 10.1016/j.jdermsci.2013.01.013] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2012] [Revised: 01/21/2013] [Accepted: 01/31/2013] [Indexed: 01/10/2023]
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Terakado K, Yogo T, Kohara Y, Soeta S, Nezu Y, Harada Y, Hara Y, Amasaki H, Tagawa M. Marked depletion of the water-channel protein, AQP5, in the canine nictitating membrane glands might contribute to the development of KCS. Vet Pathol 2012; 50:664-7. [PMID: 23160543 DOI: 10.1177/0300985812467467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The objectives of this study were to investigate the normal histological localization of aquaporin (AQP) 5 protein in the lacrimal and nictitating membrane glands and to compare this localization in healthy and keratoconjunctivitis sicca (KCS) dogs. Lacrimal and nictitating membrane glands of 5 healthy Beagles and nictitating membrane glands of 5 KCS dogs (3 Beagles and 2 mongrel dogs: 0-13 years) were used for the present study. The owners of the KCS dogs did not consent to perform biopsies of the lacrimal glands. The localization and distribution of AQP5 protein were investigated by an immunohistochemical technique. In immunohistochemical staining, AQP5 was localized in the apical site of acinar epithelial and ductal epithelial cells from both the lacrimal and nictitating membrane glands in healthy dogs. However, AQP5 was not detected in the 5 KCS dogs. These results for immunohistochemical AQP5 localization might correlate with the deficiency in tear secretion found in KCS dogs.
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Affiliation(s)
- K Terakado
- Department of Veterinary Surgery, Nippon Veterinary and Life Science University, 1-7-1 Kyonancho Musashino, Tokyo 180-8602, Japan.
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Yu D, Thelin WR, Randell SH, Boucher RC. Expression profiles of aquaporins in rat conjunctiva, cornea, lacrimal gland and Meibomian gland. Exp Eye Res 2012; 103:22-32. [PMID: 22828047 DOI: 10.1016/j.exer.2012.07.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2012] [Revised: 06/29/2012] [Accepted: 07/12/2012] [Indexed: 12/22/2022]
Abstract
The aim of the study was to elucidate aquaporin (AQP) family member mRNA expression and protein expression/localization in the rat lacrimal functional unit. The mRNA expression of all rat AQPs (AQP0-9, 11-12) in palpebral, fornical, and bulbar conjunctiva, cornea, lacrimal gland, and Meibomian gland was measured by Reverse Transcriptase-Polymerase Chain Reaction (RT-PCR) and real time RT-PCR. Antibodies against AQP1, 3, 4, 5, 9, and 11 were used in Western blotting and immunohistochemistry to determine protein expression and distribution. Our study demonstrated characteristic AQP expression profiles in rat ocular tissues. AQP1, 3, 4, 5, 8, 9, 11, and 12 mRNA were detected in conjunctiva. AQP0, 1, 2, 3, 4, 5, 6, 11, and 12 mRNA were expressed in cornea. AQP0, 1, 2, 3, 4, 5, 7, 8, and 11 mRNA were detected in lacrimal gland. AQP1, 3, 4, 5, 7, 8, 9, 11, and 12 mRNA were identified in Meibomian gland. By Western blot, AQP1, 3, 5, and 11 were detected in conjunctiva; AQP1, 3, 5, and 11 were identified in cornea; AQP1, 3, 4, 5, and 11 were detected in lacrimal gland; and AQP1, 3, 4, 5, 9, and 11 were present in Meibomian gland. Immunohistochemistry localized AQPs to distinct sites in the various tissues. This study rigorously analyzed AQPs expression and localization in rat conjunctiva, cornea, lacrimal gland, and Meibomian gland tissues. Our findings provide a comprehensive platform for further investigation into the physiological or pathophysiological relevance of AQPs in ocular surface.
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Affiliation(s)
- Dongfang Yu
- Cystic Fibrosis/Pulmonary Research and Treatment Center, University of North Carolina, Chapel Hill, 7011 Thurston-Bowles Building, 96 Manning Drive, NC 27599, United States
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Dysfunction of lacrimal and salivary glands in Sjögren's syndrome: nonimmunologic injury in preinflammatory phase and mouse model. J Biomed Biotechnol 2011; 2011:407031. [PMID: 21660135 PMCID: PMC3110304 DOI: 10.1155/2011/407031] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2010] [Revised: 02/08/2011] [Accepted: 03/08/2011] [Indexed: 11/30/2022] Open
Abstract
Sjögren's syndrome (SjS) is a chronic autoimmune disorder characterized by dry eyes and dry mouth due to dacryoadenitis and sialoadenitis with SS-A/Ro and/or SS-B/La autoantibodies in genetically predisposed individuals. Destruction of lacrimal and salivary glands by autoimmune reactions may lead to clinical manifestation. However, the mechanisms behind the decreased volume of secretions in tears and saliva are complex and are not fully understood. Exocrine gland dysfunction may precede autoimmunity (acquired immunity) or represent a process independent from inflammation in the pathogenesis of SjS. The preceded functional and morphologic changes of those tissues by nonimmunologic injury before the development of inflammation at the sites of target organs have been implicated. This paper focuses on the several factors and components relating to glandular dysfunction and morphologic changes by nonimmunologic injury during the preinflammatory phase in mouse model, including the factors which link between innate immunity and adaptive immunity.
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Ding C, Nandoskar P, Lu M, Thomas P, Trousdale MD, Wang Y. Changes of aquaporins in the lacrimal glands of a rabbit model of Sjögren's syndrome. Curr Eye Res 2011; 36:571-8. [PMID: 21524183 DOI: 10.3109/02713683.2011.574330] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
AIMS To test the hypothesis that the expression of aquaporins (AQPs) 4 and 5 is altered in the lacrimal glands (LG) of rabbits with induced autoimmune dacryoadenitis (IAD). MATERIALS AND METHODS LGs were obtained from adult female rabbits with IAD, and age-matched female control rabbits. LGs were processed for laser capture microdissection (LCM), real time RT-PCR, Western blot, and immunofluorescence for the detection and quantification of protein and mRNAs of AQP4 and AQP5 in whole LGs, and purified acinar cells and duct cells from specific duct segments. RESULTS In rabbits with IAD, abundances of mRNAs for AQP4 and AQP5 from whole LGs were significantly lower than controls. Levels of mRNA for AQP4 were lower in most duct segments from rabbits with IAD. However, the mRNA abundance for AQP5 was significantly lower in acini from rabbits with IAD, while its abundance was higher in each duct segment. Western blot showed that the expression of AQP4 in LGs from rabbits with IAD was 36% more abundant than normal controls, whereas AQP5 was 72% less abundant. Immunofluorescence indicated that AQP4 immunoreactivity (AQP4-IR) was present on the basolateral membranes of acinar and ductal cells in control and diseased LGs, with ductal cells showing stronger AQP4-IR than acinar cells. AQP5-IR was found on apical and basolateral membranes of acinar cells, and showed a "mosaic" pattern, i.e., with some acini and/or acinar cells showing stronger AQP5-IR than others. Minimal AQP5-IR was detected in ductal cells from control animals, while its intensity was significantly increased in rabbits with IAD. CONCLUSIONS These data strongly support our hypothesis that expressions of AQPs are altered in rabbits with IAD, and that specific ductal segment play important roles in lacrimal secretion.
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Affiliation(s)
- Chuanqing Ding
- Department of Cell and Neurobiology, University of Southern California, Keck School of Medicine, Los Angeles, California 90089-9112, USA
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Eberhardt C, Amann B, Feuchtinger A, Hauck SM, Deeg CA. Differential expression of inwardly rectifying K+ channels and aquaporins 4 and 5 in autoimmune uveitis indicates misbalance in Müller glial cell-dependent ion and water homeostasis. Glia 2011; 59:697-707. [DOI: 10.1002/glia.21139] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2010] [Accepted: 12/15/2010] [Indexed: 12/24/2022]
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Fischbarg J. Fluid Transport Across Leaky Epithelia: Central Role of the Tight Junction and Supporting Role of Aquaporins. Physiol Rev 2010; 90:1271-90. [DOI: 10.1152/physrev.00025.2009] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The mechanism of epithelial fluid transport remains unsolved, which is partly due to inherent experimental difficulties. However, a preparation with which our laboratory works, the corneal endothelium, is a simple leaky secretory epithelium in which we have made some experimental and theoretical headway. As we have reported, transendothelial fluid movements can be generated by electrical currents as long as there is tight junction integrity. The direction of the fluid movement can be reversed by current reversal or by changing junctional electrical charges by polylysine. Residual endothelial fluid transport persists even when no anions (hence no salt) are being transported by the tissue and is only eliminated when all local recirculating electrical currents are. Aquaporin (AQP) 1 is the only AQP present in these cells, and its deletion in AQP1 null mice significantly affects cell osmotic permeability (by ∼40%) but fluid transport much less (∼20%), which militates against the presence of sizable water movements across the cell. In contrast, AQP1 null mice cells have reduced regulatory volume decrease (only 60% of control), which suggests a possible involvement of AQP1 in either the function or the expression of volume-sensitive membrane channels/transporters. A mathematical model of corneal endothelium we have developed correctly predicts experimental results only when paracellular electro-osmosis is assumed rather than transcellular local osmosis. Our evidence therefore suggests that the fluid is transported across this layer via the paracellular route by a mechanism that we attribute to electro-osmotic coupling at the junctions. From our findings we have developed a novel paradigm for this preparation that includes 1) paracellular fluid flow; 2) a crucial role for the junctions; 3) hypotonicity of the primary secretion; and 4) an AQP role in regulation rather than as a significant water pathway. These elements are remarkably similar to those proposed by the laboratory of Adrian Hill for fluid transport across other leaky epithelia.
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Affiliation(s)
- Jorge Fischbarg
- Institute of Cardiology Research “A. C. Taquini,” University of Buenos Aires and National Council for Scientific and Technical Investigations, Buenos Aires, Argentina
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The subcellular distribution of aquaporin 5 in the cochlea reveals a water shunt at the perilymph–endolymph barrier. Neuroscience 2010; 168:957-70. [DOI: 10.1016/j.neuroscience.2009.09.002] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2009] [Revised: 08/30/2009] [Accepted: 09/01/2009] [Indexed: 11/23/2022]
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Shen Y, Wang Y, Chen Z, Wang D, Wang X, Jin M, Bai C. Role of aquaporin 5 in antigen-induced airway inflammation and mucous hyperproduction in mice. J Cell Mol Med 2010; 15:1355-63. [PMID: 20550619 PMCID: PMC4373335 DOI: 10.1111/j.1582-4934.2010.01103.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Airway inflammation and mucus hyperproduction play the central role in the development of asthma, although the mechanisms remain unclear. The aquaporin (AQP)-5 may be involved in the process due to its contribution to the volume of liquid secreted from the airways. The present study firstly found the overexpression of AQP5 in the airway epithelium and submucosal glands of asthmatics. Furthermore, we aimed at evaluating the role of AQP5 in airway inflammation and mucous hyperproductions during chronic allergic responses to house dust mite (HDM). Bronchoalveolar lavage levels of interleukin (IL)-2, IL-4, IL-10, interferon-γ and Mucin 5AC (MUC5AC), and number of peribronchial and perivascular cells were measured in AQP5 wild-type and AQP5 knockout (KO) mice. We found that HDM induced airway inflammation, lung Th2 cell accumulation and mucin hypersecretion in C57BL/6 mice rather than AQP5 KO mice. Expression of MUC5AC and MUC5B proteins and genes in the lung tissue was significantly lower in AQP5 KO mice. Thus, our results implicate involvement of AQP5 in the development of airway inflammation and mucous hyperproduction during chronic asthma.
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Affiliation(s)
- Yao Shen
- Department of Pulmonary Medicine, Zhongshan Hospital, Fudan University, Shanghai, China
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Verkman AS. Aquaporins: translating bench research to human disease. ACTA ACUST UNITED AC 2009; 212:1707-15. [PMID: 19448080 DOI: 10.1242/jeb.024125] [Citation(s) in RCA: 121] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
There is considerable potential for translating knowledge of aquaporin structure, function and physiology to the clinic. One area is in aquaporin-based diagnostics. The discovery of AQP4 autoantibodies as a marker of the neuromyelitis optica form of multiple sclerosis has allowed precise diagnosis of this disease. Other aquaporin-based diagnostics are possible. Another area is in aquaporin-based genetics. Genetic diseases caused by loss-of-function mutations in aquaporins include nephrogenic diabetes insipidus and cataracts, and functionally significant aquaporin polymorphisms are beginning to be explored. Perhaps of greatest translational potential is aquaporin-based therapeutics. Information largely from aquaporin knockout mice has implicated key roles of aquaporin-facilitated water transport in transepithelial fluid transport (urinary concentrating, gland fluid secretion), water movement into and out of the brain, cell migration (angiogenesis, tumor metastasis, wound healing) and neural function (sensory signaling, seizures). A subset of aquaporins that transport both water and glycerol, the 'aquaglyceroporins', regulate glycerol content in epidermal, fat and other tissues, and are involved in skin hydration, cell proliferation, carcinogenesis and fat metabolism. Aquaporin-based modulator drugs are predicted to be of broad potential utility in the treatment of edematous states, cancer, obesity, wound healing, epilepsy and glaucoma. These exciting possibilities and their associated challenges are reviewed.
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Affiliation(s)
- A S Verkman
- Department of Medicine, Cardiovascular Research Institute, University of California, San Francisco, CA 94143, USA.
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Li L, Zhang H, Ma T, Verkman AS. Very high aquaporin-1 facilitated water permeability in mouse gallbladder. Am J Physiol Gastrointest Liver Physiol 2009; 296:G816-22. [PMID: 19179619 PMCID: PMC2670675 DOI: 10.1152/ajpgi.90680.2008] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Water transport across gallbladder epithelium is driven by osmotic gradients generated from active salt absorption and secretion. Aquaporin (AQP) water channels have been proposed to facilitate transepithelial water transport in gallbladder and to modulate bile composition. We found strong AQP1 immunofluorescence at the apical membrane of mouse gallbladder epithelium. Transepithelial osmotic water permeability (Pf) was measured in freshly isolated gallbladder sacs from the kinetics of luminal calcein self-quenching in response to an osmotic gradient. Pf was very high (0.12 cm/s) in gallbladders from wild-type mice, cAMP independent, and independent of osmotic gradient size and direction. Although gallbladders from AQP1 knockout mice had similar size and morphology to those from wild-type mice, their Pf was reduced by approximately 10-fold. Apical plasma membrane water permeability was greatly reduced in AQP1-deficient gallbladders, as measured by cytoplasmic calcein quenching in perfluorocarbon-filled, inverted gallbladder sacs. However, neither bile osmolality nor bile salt concentration differed in gallbladders from wild-type vs. AQP1 knockout mice. Our data indicate constitutively high water permeability in mouse gallbladder epithelium involving transcellular water transport through AQP1. The similar bile salt concentration in gallbladders from AQP1 knockout mice argues against a physiologically important role for AQP1 in mouse gallbladder.
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Affiliation(s)
- Lihua Li
- Membrane Channel Research Laboratory, Northeast Normal University, Changchun, People's Republic of China; and Departments of Medicine and Physiology, University of California, San Francisco, California
| | - Hua Zhang
- Membrane Channel Research Laboratory, Northeast Normal University, Changchun, People's Republic of China; and Departments of Medicine and Physiology, University of California, San Francisco, California
| | - Tonghui Ma
- Membrane Channel Research Laboratory, Northeast Normal University, Changchun, People's Republic of China; and Departments of Medicine and Physiology, University of California, San Francisco, California
| | - A. S. Verkman
- Membrane Channel Research Laboratory, Northeast Normal University, Changchun, People's Republic of China; and Departments of Medicine and Physiology, University of California, San Francisco, California
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Ruiz-Ederra J, Levin MH, Verkman AS. In situ fluorescence measurement of tear film [Na+], [K+], [Cl-], and pH in mice shows marked hypertonicity in aquaporin-5 deficiency. Invest Ophthalmol Vis Sci 2009; 50:2132-8. [PMID: 19136711 DOI: 10.1167/iovs.08-3033] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE Tear film composition depends on water and ion transport across ocular surface epithelia and on fluid secretion by lacrimal glands. The purpose of this study was to establish in situ fluorescence methods to measure tear film ionic concentrations and pH in mice and to determine whether tear film composition is sensitive to deficiency of the major ocular surface aquaporin water channels. METHODS Tear film ionic concentrations and pH were measured in anesthetized mice by ratio imaging fluorescence microscopy after topical application of ion/pH-sensing, dual-wavelength fluorescent indicators. [Na(+)], [K(+)], and [Cl(-)] were measured with membrane-impermeant indicators developed by our laboratory, and pH was measured with bis(carboxyethyl)-carboxyfluorescein fluorescence-conjugated dextran. Measurements were performed on wild-type mice and on knockout mice lacking aquaporins AQP1, AQP3, and AQP5. RESULTS In wild-type mice, tear film [Na(+)] was 139 +/- 8 mM, [K(+)] was 48 +/- 1 mM, [Cl(-)] was 127 +/- 4 mM, and pH was 7.59 +/- 0.2 (SE; n = 5-8). pH did not differ significantly in the AQP knockout mice. [Na(+)] was increased by approximately twofold in AQP5 null mice (230 +/- 20 mM) and was greatly reduced after exposure of the ocular surface to a humidified atmosphere. [K(+)] was mildly reduced in AQP1 null mice. CONCLUSIONS These results establish an in situ optical methodology to measure tear film [Na(+)], [K(+)], [Cl(-)], and pH in living mice, without the need for fluid sampling. Tear film hypertonicity in AQP5 deficiency is likely caused by reduced transcorneal water secretion in response to evaporative water loss.
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Affiliation(s)
- Javier Ruiz-Ederra
- Department of Medicine and Physiology, Cardiovascular Research Institute, University of California, San Francisco, California 94143-0521, USA
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Tradtrantip L, Tajima M, Li L, Verkman AS. Aquaporin water channels in transepithelial fluid transport. THE JOURNAL OF MEDICAL INVESTIGATION 2009; 56 Suppl:179-84. [DOI: 10.2152/jmi.56.179] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Affiliation(s)
| | - Masato Tajima
- Departments of Medicine and Physiology, University of California
| | - Lihua Li
- Departments of Medicine and Physiology, University of California
| | - AS Verkman
- Departments of Medicine and Physiology, University of California
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Abstract
The study of water transport began long before the molecular identification of water channels with studies of water-permeable tissues. The discovery of the first aquaporin, AQP1, occurred during experiments focused on the identity of the Rh blood group antigens. Since then the field has expanded dramatically to study aquaporins in all types of organisms. In mammals, some of the aquaporins transport only water. However, there are some family members that collectively transport a diverse set of solutes. The aquaporins can be regulated by factors that affect channel permeability or subcellular localization. An extensive set of studies examines the physiological role of many of the mammalian aquaporins. However, much is still to be discovered about the physiological role of this membrane protein family.
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Abstract
Knockout mice have been informative in the discovery of unexpected biological functions of aquaporins. Knockout mice have confirmed the predicted roles of aquaporins in transepithelial fluid transport, as in the urinary concentrating mechanism and glandular fluid secretion. A less obvious, though predictable role of aquaporins is in tissue swelling under stress, as in the brain in stroke, tumor and infection. Phenotype analysis of aquaporin knockout mice has revealed several unexpected cellular roles of aquaporins whose mechanisms are being elucidated. Aquaporins facilitate cell migration, as seen in aquaporin-dependent tumor angiogenesis and tumor metastasis, by a mechanism that may involve facilitated water transport in lamellipodia of migrating cells. The ' aquaglyceroporins', aquaporins that transport both glycerol and water, regulate glycerol content in epidermis, fat and other tissues, and lead to a multiplicity of interesting consequences of gene disruption including dry skin, resistance to skin carcinogenesis, impaired cell proliferation and altered fat metabolism. An even more surprising role of a mammalian aquaporin is in neural signal transduction in the central nervous system. The many roles of aquaporins might be exploited for clinical benefit by modulation of aquaporin expression/function - as diuretics, and in the treatment of brain swelling, glaucoma, epilepsy, obesity and cancer.
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Affiliation(s)
- Alan S Verkman
- Departments of Medicine and Physiology, Cardiovascular Research Institute, University of California, San Francisco, CA, 94143-0521, USA.
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Mochida H, Nakakura T, Suzuki M, Hayashi H, Kikuyama S, Tanaka S. Immunolocalization of a mammalian aquaporin 3 homolog in water-transporting epithelial cells in several organs of the clawed toad Xenopus laevis. Cell Tissue Res 2008; 333:297-309. [PMID: 18548281 DOI: 10.1007/s00441-008-0628-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2008] [Accepted: 04/28/2008] [Indexed: 12/13/2022]
Abstract
Nucleotide sequences of cDNA were used to construct antibodies against an aquaporin (AQP) expressed in the clawed toad, Xenopus laevis, viz., Xenopus AQP3, a homolog of mammalian AQP3. Xenopus AQP3 was immunolocalized in the basolateral membrane of the principal cells of the ventral skin, the urinary bladder, the collecting duct and late distal tubule of the kidney, the absorptive epithelial cells of the large intestine, and the ciliated epithelial cells of the oviducts. Therefore, we designated this AQP as basolateral Xenopus AQP3 (AQP-x3BL). The intensity of labeling for AQP-x3BL differed between the ventral and dorsal skin, with the basolateral membrane of the principal cells in the ventral skin showing intense labeling, whereas that in the dorsal skin was lightly labeled. AQP-x3BL was also immunolocalized in the basolateral membrane of secretory cells in the small granular and mucous glands of the skin. As AQP-x5, a homolog of mammalian AQP5, is localized in the apical membrane of these same cells, this provides a pathway for fluid secretion by the glands. Although Hyla AQP-h2 is translocated from the cytoplasm to the apical membrane of the Hyla urinary bladder in response to arginine vasotocin (AVT), AQP-h2 immunoreactivity in Xenopus bladder remains in the cytoplasm and barely moves to the apical membrane, regardless of AVT stimulation. AQP-x3 is localized in the basolateral membrane, even though the AVT-stimulated AQP-h2 does not translocate to the apical membrane. These findings provide new insights into AQP function in aquatic anurans.
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Affiliation(s)
- Hiroshi Mochida
- Department of Environmental Science, Shizuoka University, Ohya 836, Suruga-ku, Shizuoka, Japan
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