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Schneider-Futschik EK, Zhu Y, Li D, Habgood MD, Nguyen BN, Pankonien I, Amaral MD, Downie LE, Chinnery HR. The role of CFTR in the eye, and the effect of early highly effective modulator treatment for cystic fibrosis on eye health. Prog Retin Eye Res 2024; 103:101299. [PMID: 39245300 DOI: 10.1016/j.preteyeres.2024.101299] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2024] [Revised: 08/14/2024] [Accepted: 09/05/2024] [Indexed: 09/10/2024]
Abstract
Cystic fibrosis transmembrane conductance regulator (CFTR) is a protein that plays a crucial role in various human organs, including the respiratory and digestive systems. Dysfunctional CFTR is the key variant of the lethal genetic disorder, cystic fibrosis (CF). In the past decade, highly effective CFTR modulator therapies, including elexacaftor-tezacaftor-ivacaftor, have revolutionised CF management by correcting the underlying molecular defect to improve patient outcomes and life expectancy. Despite demonstrating multiorgan efficacy, clinical studies have largely overlooked the potential for ocular disturbances with CFTR modulator therapy, with the exception of a few case studies reporting the presence of crystalline lens pathologies in young children on CFTR modulators, and in breastfed infants born to individuals who were on CFTR modulator treatment during pregnancy. CFTR is present in multiple tissues during embryonic development, including the eye, and its expression can be influenced by genetic and environmental factors. This review summarises the role of CFTR in the eye, and the potential impact of CFTR on eye function and vision later in life. This information provides a framework for understanding the use and possible effects of CFTR-modulating therapeutics in the context of eye health, including the potential to leverage the eye for non-invasive and accessible diagnostic and monitoring capabilities in patients with CF.
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Affiliation(s)
- Elena K Schneider-Futschik
- Department of Biochemistry and Pharmacology, School of Biomedical Sciences, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Parkville, VIC, 3010, Australia.
| | - Yimin Zhu
- Department of Biochemistry and Pharmacology, School of Biomedical Sciences, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Parkville, VIC, 3010, Australia
| | - Danni Li
- Department of Biochemistry and Pharmacology, School of Biomedical Sciences, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Parkville, VIC, 3010, Australia
| | - Mark D Habgood
- Department of Biochemistry and Pharmacology, School of Biomedical Sciences, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Parkville, VIC, 3010, Australia
| | - Bao N Nguyen
- Department of Optometry and Vision Sciences, The University of Melbourne, Parkville, VIC, 3010, Australia
| | - Ines Pankonien
- BioISI - Biosystems & Integrative Sciences Institute, Faculty of Sciences, University of Lisboa, Campo Grande-C8, 1749-016, Lisboa, Portugal
| | - Margarida D Amaral
- BioISI - Biosystems & Integrative Sciences Institute, Faculty of Sciences, University of Lisboa, Campo Grande-C8, 1749-016, Lisboa, Portugal
| | - Laura E Downie
- Department of Optometry and Vision Sciences, The University of Melbourne, Parkville, VIC, 3010, Australia
| | - Holly R Chinnery
- Department of Optometry and Vision Sciences, The University of Melbourne, Parkville, VIC, 3010, Australia; Lions Eye Institute, Nedlands, Western Australia, 6009, Australia; The University of Western Australia, Crawley, Western Australia, 6009, Australia
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Liberski S, Confalonieri F, Cofta S, Petrovski G, Kocięcki J. Ocular Changes in Cystic Fibrosis: A Review. Int J Mol Sci 2024; 25:6692. [PMID: 38928397 PMCID: PMC11203677 DOI: 10.3390/ijms25126692] [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: 04/22/2024] [Revised: 06/10/2024] [Accepted: 06/11/2024] [Indexed: 06/28/2024] Open
Abstract
Cystic fibrosis (CF), also known as mucoviscidosis, is the most common autosomal recessive genetic disease in the Caucasian population, with an estimated frequency of 1:2000-3000 live births. CF results from the mutation of the cystic fibrosis transmembrane conductance regulator (CFTR) gene localized in the long arm of chromosome 7. The product of CFTR gene expression is CFTR protein, an adenosine triphosphate (ATP)-binding cassette (ABC) transporter that regulates the transport of chloride ions (Cl-) across the apical cell membrane. Primary manifestations of CF include chronic lung and pancreas function impairment secondary to the production of thick, sticky mucus resulting from dehydrated secretions. It is well known that CF can cause both anterior and posterior ocular abnormalities. Conjunctival and corneal xerosis and dry eye disease symptoms are the most characteristic manifestations in the anterior segment. In contrast, the most typical anatomical and functional changes relating to the posterior segment of the eye include defects in the retinal nerve fiber layer (RNFL), vascular abnormalities, and visual disturbances, such as reduced contrast sensitivity and abnormal dark adaptation. However, the complete background of ophthalmic manifestations in the course of CF has yet to be discovered. This review summarizes the current knowledge regarding ocular changes in cystic fibrosis.
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Affiliation(s)
- Slawomir Liberski
- Department of Ophthalmology, Poznan University of Medical Sciences, A. Szamarzewskiego 84, 61-848 Poznan, Poland;
| | - Filippo Confalonieri
- Department of Ophthalmology, IRCCS Humanitas Research Hospital, 20089 Rozzano, Milan, Italy;
- Department of Biomedical Sciences, Humanitas University, 20090 Pieve Emanuele, Milan, Italy
- Center for Eye Research and Innovative Diagnostics, Department of Ophthalmology, Institute for Clinical Medicine, University of Oslo, Kirkeveien 166, 0450 Oslo, Norway;
- Department of Ophthalmology, Oslo University Hospital, Kirkeveien 166, 0450 Oslo, Norway
| | - Szczepan Cofta
- Department of Respiratory Medicine, Allergology and Pulmonary Oncology, Poznan University of Medical Sciences, A. Szamarzewskiego 84, 61-848 Poznan, Poland;
| | - Goran Petrovski
- Center for Eye Research and Innovative Diagnostics, Department of Ophthalmology, Institute for Clinical Medicine, University of Oslo, Kirkeveien 166, 0450 Oslo, Norway;
- Department of Ophthalmology, Oslo University Hospital, Kirkeveien 166, 0450 Oslo, Norway
| | - Jarosław Kocięcki
- Department of Ophthalmology, Poznan University of Medical Sciences, A. Szamarzewskiego 84, 61-848 Poznan, Poland;
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Jeon HS, Kang B, Li X, Song JS. Differences in vulnerability to desiccating stress between corneal and conjunctival epithelium in rabbit models of short-term ocular surface exposure. Sci Rep 2022; 12:16941. [PMID: 36209216 PMCID: PMC9547869 DOI: 10.1038/s41598-022-21478-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Accepted: 09/27/2022] [Indexed: 12/29/2022] Open
Abstract
We evaluate the difference in vulnerability to desiccating stress (DS) between the corneal and conjunctival epithelia to understand different ocular surface staining patterns in dry eye patients. We generated a rabbit model of short-term exposure keratopathy. To induce DS in the ocular surface, rabbit right eyelids were opened for 30 min, with blinking once/minute. Corneal staining scores increased from 3-min post-DS exposure, while conjunctival staining increased from 20-min post-DS. At 20 min, the tear MUC5AC level doubled as compared to pre-DS (p = 0.007). In Western blot analysis, conjunctival AQP5, MUC5AC, and CFTR expression increased significantly in response to DS, compared to control (p = 0.039, 0.002, 0.039, respectively). Immunohistochemistry for CD31 and LYVE-1 were performed. CD31-positive cells and lymphatic space surrounded by LYVE-1-positive cells increased significantly in conjunctival tissue post-DS, compared to control (p = 0.0006, p < 0.0001, respectively). Surface damage was worse in the corneal than in the conjunctival epithelium after DS, by scanning electron microscopy. This study showed that the cornea and conjunctival epithelium show differences in vulnerability to DS. Increased blood vessels and dilated lymphatics, accompanied by increased conjunctival epithelial AQP5, MUC5AC, and CFTR expression, underlie the protective mechanism of the conjunctiva to desiccating stress.
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Affiliation(s)
- Hyun Sun Jeon
- grid.222754.40000 0001 0840 2678Department of Ophthalmology, Korea University College of Medicine, Seoul, South Korea ,grid.31501.360000 0004 0470 5905Department of Ophthalmology, Seoul National University College of Medicine, Seoul, South Korea
| | - Boram Kang
- grid.222754.40000 0001 0840 2678Department of Ophthalmology, Korea University College of Medicine, Seoul, South Korea
| | - Xuemin Li
- grid.222754.40000 0001 0840 2678Department of Ophthalmology, Korea University College of Medicine, Seoul, South Korea
| | - Jong Suk Song
- grid.222754.40000 0001 0840 2678Department of Ophthalmology, Korea University College of Medicine, Seoul, South Korea
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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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Fini ME, Jeong S, Gong H, Martinez-Carrasco R, Laver NMV, Hijikata M, Keicho N, Argüeso P. Membrane-associated mucins of the ocular surface: New genes, new protein functions and new biological roles in human and mouse. Prog Retin Eye Res 2019; 75:100777. [PMID: 31493487 DOI: 10.1016/j.preteyeres.2019.100777] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Revised: 08/26/2019] [Accepted: 08/31/2019] [Indexed: 01/17/2023]
Abstract
The mucosal glycocalyx of the ocular surface constitutes the point of interaction between the tear film and the apical epithelial cells. Membrane-associated mucins (MAMs) are the defining molecules of the glycocalyx in all mucosal epithelia. Long recognized for their biophysical properties of hydration, lubrication, anti-adhesion and repulsion, MAMs maintain the wet ocular surface, lubricate the blink, stabilize the tear film and create a physical barrier to the outside world. However, it is increasingly appreciated that MAMs also function as cell surface receptors that transduce information from the outside to the inside of the cell. A number of excellent review articles have provided perspective on the field as it has progressed since 1987, when molecular cloning of the first MAM was reported. The current article provides an update for the ocular surface, placing it into the broad context of findings made in other organ systems, and including new genes, new protein functions and new biological roles. We discuss the epithelial tissue-equivalent with mucosal differentiation, the key model system making these advances possible. In addition, we make the first systematic comparison of MAMs in human and mouse, establishing the basis for using knockout mice for investigations with the complexity of an in vivo system. Lastly, we discuss findings from human genetics/genomics, which are providing clues to new MAM roles previously unimagined. Taken together, this information allows us to generate hypotheses for the next stage of investigation to expand our knowledge of MAM function in intracellular signaling and roles unique to the ocular surface.
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Affiliation(s)
- M Elizabeth Fini
- Department of Ophthalmology, Tufts University School of Medicine, at New England Eye Center, Tufts Medical Center, 800 Washington St, Boston, MA, 02111, USA.
| | - Shinwu Jeong
- USC Roski Eye Institute and Department of Ophthalmology, Keck School of Medicine of USC, University of Southern California, 1975 Zonal Ave, Los Angeles, CA, 90033, USA.
| | - Haiyan Gong
- Department of Ophthalmology, Boston University School of Medicine, 72 E Concord St, Boston, MA, 02118, USA.
| | - Rafael Martinez-Carrasco
- Department of Ophthalmology, Tufts University School of Medicine, at New England Eye Center, Tufts Medical Center, 800 Washington St, Boston, MA, 02111, USA.
| | - Nora M V Laver
- Department of Ophthalmology, Tufts University School of Medicine, at New England Eye Center, Tufts Medical Center, 800 Washington St, Boston, MA, 02111, USA.
| | - Minako Hijikata
- Department of Pathophysiology and Host Defense, The Research Institute of Tuberculosis, Japan Anti-Tuberculosis Association, 3-1-24 Matsuyama, Kiyose-shi, Tokyo, 204-8533, Japan.
| | - Naoto Keicho
- Department of Pathophysiology and Host Defense, The Research Institute of Tuberculosis, Japan Anti-Tuberculosis Association, 3-1-24 Matsuyama, Kiyose-shi, Tokyo, 204-8533, Japan.
| | - Pablo Argüeso
- Department of Ophthalmology, Harvard Medical School, at Schepens Eye Research Institute of Mass. Eye and Ear, 20 Staniford St, Boston, MA, 02114, USA.
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Berczeli O, Vizvári E, Katona M, Török D, Szalay L, Rárosi F, Németh I, Rakonczay Z, Hegyi P, Ding C, Tóth-Molnár E. Novel Insight Into the Role of CFTR in Lacrimal Gland Duct Function in Mice. Invest Ophthalmol Vis Sci 2018; 59:54-62. [PMID: 29305607 PMCID: PMC5756044 DOI: 10.1167/iovs.17-22533] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Purpose The role of cystic fibrosis transmembrane conductance regulator (CFTR) in lacrimal gland (LG) function has only recently received some attention, mainly from our group. In the present study, we investigated the potential changes of LG pathology, tear secretion, ocular surface integrity, and fluid secretion in isolated LG ducts from CFTR knockout (KO) mice. Methods Tear production and ocular surface integrity were investigated in anesthetized wild-type (WT) and KO mice using cotton threads and fluorescein staining, respectively. Immunofluorescence was used to localize CFTR protein in the LGs. Ductal fluid secretions evoked by forskolin (10 μM); cell-permeable cAMP analogue (8-bromo cAMP, 100 μM); or carbachol (100 μM) were measured in isolated LG ducts using video-microscopy. Intracellular Ca2+ homeostasis underlying carbachol stimulation was investigated with microfluorometry. Results Significant decrease in tear secretion and impaired ocular surface integrity were observed in KO mice. Immunofluorescence demonstrated the predominant presence of CFTR protein in the apical membranes of the duct cells from WT mice. Continuous fluid secretion was evoked by forskolin and 8-bromo cAMP in LG ducts from WT mice, while no secretory response was observed in ducts from KO mice. Carbachol caused similar secretory responses in ducts from WT and KO animals without significant differences in cytosolic Ca2+ signaling. Conclusions Our results suggest the important role of CFTR in LG ductal secretion and in the maintenance of ocular surface integrity, suggesting that CFTR may be a promising target of novel therapeutic approaches in the treatment of dry eye.
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Affiliation(s)
- Orsolya Berczeli
- Department of Ophthalmology, University of Szeged, Szeged, Hungary
| | - Eszter Vizvári
- Department of Ophthalmology, University of Szeged, Szeged, Hungary
| | - Máté Katona
- 1st Department of Internal Medicine, University of Szeged, Szeged, Hungary
| | - Dénes Török
- Department of Anatomy, University of Szeged, Szeged, Hungary
| | - László Szalay
- Department of Ophthalmology, University of Szeged, Szeged, Hungary
| | - Ferenc Rárosi
- Department of Medical Physics and Informatics, University of Szeged, Szeged, Hungary
| | - István Németh
- Department of Dermatology and Allergology, University of Szeged, Szeged, Hungary
| | - Zoltán Rakonczay
- 1st Department of Internal Medicine, University of Szeged, Szeged, Hungary.,Department of Pathophysiology, University of Szeged, Szeged, Hungary
| | - Péter Hegyi
- Institute for Translational Medicine and First Department of Medicine, University of Pécs, Pécs, Hungary.,MTA-SZTE Translational Gastroenterology Research Group, Szeged, Hungary
| | - Chuanqing Ding
- Pharmacology & Pharmaceutical Sciences, Ophthalmology, University of Southern California, Los Angeles, California, United States
| | - Edit Tóth-Molnár
- Department of Ophthalmology, University of Szeged, Szeged, Hungary.,Department of Pharmacology and Pharmacotherapy, University of Szeged, Szeged, Hungary
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Yu D, Davis RM, Aita M, Burns KA, Clapp PW, Gilmore RC, Chua M, O'Neal WK, Schlegel R, Randell SH, C Boucher R. Characterization of Rat Meibomian Gland Ion and Fluid Transport. Invest Ophthalmol Vis Sci 2016; 57:2328-43. [PMID: 27127933 PMCID: PMC4855829 DOI: 10.1167/iovs.15-17945] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Purpose We establish novel primary rat meibomian gland (MG) cell culture systems and explore the ion transport activities of the rat MG. Methods Freshly excised rat MG tissues were characterized as follows: (1) mRNA expression of selected epithelial ion channels/transporters were measured by RT-PCR, (2) localization of epithelial sodium channel (ENaC) mRNAs was performed by in situ hybridization, and (3) protein expression and localization of βENaC, the Na+/K+/Cl− cotransporter (NKCC), and the Na+/K+ ATPase were evaluated by immunofluorescence. Primary isolated rat MG cells were cocultured with 3T3 feeder cells and a Rho-associated kinase (ROCK) inhibitor (Y-27632) for expansion. Passaged rat MG cells were cultured as planar sheets under air-liquid interface (ALI) conditions for gene expression and electrophysiologic studies. Passaged rat MG cells also were cultured in matrigel matrices to form spheroids, which were examined ultrastructurally by transmission electron microscopy (TEM) and functionally using swelling assays. Results Expression of multiple ion channel/transporter genes was detected in rat MG tissues. β-ENaC mRNA and protein were localized more to MG peripheral acinar cells than central acinar cells or ductular epithelial cells. Electrophysiologic studies of rat MG cell planar cultures demonstrated functional sodium, chloride, and potassium channels, and cotransporters activities. Transmission electron microscopic analyses of rat MG spheroids revealed highly differentiated MG cells with abundant lysosomal lamellar bodies. Rat MG spheroids culture-based measurements demonstrated active volume regulation by ion channels. Conclusions This study demonstrates the presence and function of ion channels and volume transport by rat MG. Two novel primary MG cell culture models that may be useful for MG research were established.
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Affiliation(s)
- Dongfang Yu
- Marsico Lung Institute/UNC Cystic Fibrosis Research Center School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States
| | - Richard M Davis
- Department of Ophthalmology, The University of North Carolina, Chapel Hill, North Carolina, United States
| | - Megumi Aita
- Neuroscience Center, The University of North Carolina, Chapel Hill, North Carolina, United States
| | - Kimberlie A Burns
- Marsico Lung Institute/UNC Cystic Fibrosis Research Center School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States
| | - Phillip W Clapp
- Marsico Lung Institute/UNC Cystic Fibrosis Research Center School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States
| | - Rodney C Gilmore
- Marsico Lung Institute/UNC Cystic Fibrosis Research Center School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States
| | - Michael Chua
- Marsico Lung Institute/UNC Cystic Fibrosis Research Center School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States
| | - Wanda K O'Neal
- Marsico Lung Institute/UNC Cystic Fibrosis Research Center School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States
| | - Richard Schlegel
- Department of Pathology, Georgetown University Medical School, Washington District of Columbia, United States
| | - Scott H Randell
- Marsico Lung Institute/UNC Cystic Fibrosis Research Center School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States
| | - Richard C Boucher
- Marsico Lung Institute/UNC Cystic Fibrosis Research Center School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States
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Hiscox RJ, Purslow C, North RV, Ketchell I, Evans KSE. Branch retinal vein occlusion in an asymptomatic adult with cystic fibrosis. Optom Vis Sci 2014; 91:S52-4. [PMID: 24584306 DOI: 10.1097/opx.0000000000000186] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
PURPOSE This article aims to describe a case of asymptomatic branch retinal vein occlusion (BRVO) in a patient with cystic fibrosis (CF) and discuss the possible link between the two. CASE REPORT A young adult (aged 35 years) with CF who presented for routine ocular examination was found to have a superior temporal BRVO in the left eye. Visual acuity was unaffected, measuring -0.06 LogMAR, and intraocular pressure was 10 mm Hg. Optical coherence tomography showed no macular involvement. Regarding the patient's general health, blood pressure was within the normal range, and there was no diabetes. Exploratory blood tests revealed elevated fibrinogen levels. CONCLUSIONS It is hypothesized that BRVO occurred secondary to raised fibrinogen levels, a common feature in CF resulting from chronic pulmonary infection and inflammation. Practitioners should be aware of the possible link between BRVO and CF.
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Affiliation(s)
- Rachel J Hiscox
- *PhD †FRCP, PhD School of Optometry and Vision Sciences (RJH, CP, RVN, KSEE), Cardiff University, Cardiff, Wales, United Kingdom; and All Wales Adult Cystic Fibrosis Centre (IK), University Hospital, Llandough, Cardiff, Wales, United Kingdom
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Yu D, Thelin WR, Rogers TD, Stutts MJ, Randell SH, Grubb BR, Boucher RC. Regional differences in rat conjunctival ion transport activities. Am J Physiol Cell Physiol 2012; 303:C767-80. [PMID: 22814399 PMCID: PMC3469597 DOI: 10.1152/ajpcell.00195.2012] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2012] [Accepted: 07/18/2012] [Indexed: 12/26/2022]
Abstract
Active ion transport and coupled osmotic water flow are essential to maintain ocular surface health. We investigated regional differences in the ion transport activities of the rat conjunctivas and compared these activities with those of cornea and lacrimal gland. The epithelial sodium channel (ENaC), sodium/glucose cotransporter 1 (Slc5a1), transmembrane protein 16 (Tmem16a, b, f, and g), cystic fibrosis transmembrane conductance regulator (Cftr), and mucin (Muc4, 5ac, and 5b) mRNA expression was characterized by RT-PCR. ENaC proteins were measured by Western blot. Prespecified regions (palpebral, fornical, and bulbar) of freshly isolated conjunctival tissues and cell cultures were studied electrophysiologically with Ussing chambers. The transepithelial electrical potential difference (PD) of the ocular surface was also measured in vivo. The effect of amiloride and UTP on the tear volume was evaluated in lacrimal gland excised rats. All selected genes were detected but with different expression patterns. We detected αENaC protein in all tissues, βENaC in palpebral and fornical conjunctiva, and γENaC in all tissues except lacrimal glands. Electrophysiological studies of conjunctival tissues and cell cultures identified functional ENaC, SLC5A1, CFTR, and TMEM16. Fornical conjunctiva exhibited the most active ion transport under basal conditions amongst conjunctival regions. PD measurements confirmed functional ENaC-mediated Na(+) transport on the ocular surface. Amiloride and UTP increased tear volume in lacrimal gland excised rats. This study demonstrated that the different regions of the conjunctiva exhibited a spectrum of ion transport activities. Understanding the specific functions of distinct regions of the conjunctiva may foster a better understanding of the physiology maintaining hydration of the ocular surface.
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Affiliation(s)
- Dongfang Yu
- Cystic Fibrosis/Pulmonary Research and Treatment Center. Univ. of North Carolina, Chapel Hill, Chapel Hill, NC 27599, USA
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Abstract
PURPOSE We investigated the role that the cystic fibrosis transmembrane conductance regulator (CFTR) may play in Cl(-) transport in the acinar and ductal epithelial cells of rabbit lacrimal gland (LG). METHODS Primary cultured LG acinar cells were processed for whole-cell patch-clamp electrophysiological recording of Cl(-) currents by using perfusion media with high and low [Cl(-)], 10 µM forskolin and 100 µM 3-isobutyl-1-methylxanthine (IBMX), the non-specific Cl(-) channel blocker 4,4'-disothiocyanostilbene-2, 2' sulphonic acid (DIDS; 100 µM) and CFTRinh-172 (10 µM), a specific blocker for CFTR. Ex vivo live cell imaging of [Cl(-)] changes in duct cells was performed on freshly dissected LG duct with a multiphoton confocal laser scanning microscope using a Cl(-) sensitive fluorescence dye, N-[ethoxycarbonylmethyl]-6-methoxy-quinolinium bromide. RESULTS Whole-cell patch-clamp studies demonstrated the presence of Cl(-) current in isolated acinar cells and revealed that this Cl(-) current was mediated by CFTR channel. Live cell imaging also showed the presence of CFTR-mediated Cl(-) transport across the plasma membrane of duct cells. CONCLUSIONS Our previous data showed the presence of CFTR in all acinar and duct cells within the rabbit LG, with expression most prominent in the apical membranes of duct cells. The present study demonstrates that CFTR is actively involved in Cl(-) transport in both acinar cells and epithelial cells from duct segments, suggesting that CFTR may play a significant role in LG secretion.
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Affiliation(s)
- Michael Lu
- Department of Cell and Neurobiology, Doheny Eye Institute, University of Southern California, Los Angeles, CA, USA
- Department of Cell and Neurobiology, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Chuanqing Ding
- Department of Cell and Neurobiology, Doheny Eye Institute, University of Southern California, Los Angeles, CA, USA
- Department of Cell and Neurobiology, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
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Mrugacz M, Zelazowska B, Bakunowicz-Lazarczyk A, Kaczmarski M, Wysocka J. Elevated tear fluid levels of MIP-1alpha in patients with cystic fibrosis. J Interferon Cytokine Res 2007; 27:491-5. [PMID: 17572013 DOI: 10.1089/jir.2007.0149] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Cystic fibrosis (CF) is the commonest multisystem genetic disease of white races, caused by mutations in the cystic fibrosis transmembrane regulator (CFTR), encoded on the long arm of chromosome 7. Mutations in the CFTR gene result in defective sodium, chloride, and water transport in the epithelial cells of the respiratory, hepatobiliary, gastrointestinal, and reproductive tracts, the pancreas, and the eye. The pathogenesis of ocular changes in CF is still unknown, but CF belongs to the large pathologic group of ocular surface epithelial diseases, termed keratoconjunctivitis sicca (KCS), that develop in dry eye syndrome. The aim of this study was to evaluate the levels of macrophage inflammatory protein-1alpha (MIP-1alpha) in the tear fluid of CF patients. We also investigated the correlation between the tear levels of this chemokine and clinical severity of CF and ocular surface disease. We studied 25 patients with CF with a mean age of 14 years. Chemokine levels were determined by ELISA. Complete ophthalmic examination, including dry eye tests, were used to study the ocular surface. The tear levels of MIP-1alpha in the CF patients were significantly higher when compared with healthy controls. We found a negative correlation between the tear levels of MIP-1alpha and clinical severity in CF patients and a positive correlation between the tear levels of MIP-1alpha and the presence of dry eye findings in CF patients. This current study indicates that chemokines play an important role in the ongoing inflammatory response. Our findings may help to explain one of the key factors contributing to the pathogenesis of ocular surface changes in CF patients.
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Affiliation(s)
- Malgorzata Mrugacz
- Department of Pediatric Ophthalmology, Medical University of Bialystok, 15-274 Bialystok, Poland.
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Levin MH, Verkman AS. Aquaporins and CFTR in ocular epithelial fluid transport. J Membr Biol 2006; 210:105-15. [PMID: 16868675 DOI: 10.1007/s00232-005-0849-1] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2005] [Indexed: 12/13/2022]
Abstract
Aquaporins (AQPs) and the cystic fibrosis transmembrane conductance regulator (CFTR) provide the molecular routes for transport of water and chloride, respectively, through many epithelial tissues. In ocular epithelia, fluid transport generally involves secondary active chloride transport, which creates the osmotic gradient to drive transepithelial water transport. This review is focused on the role of AQPs and CFTR in water and ion transport across corneal/conjunctival epithelia, corneal endothelium, ciliary epithelium, and retinal pigment epithelium. The potential relevance of water and chloride transport to common disorders of ocular fluid balance is also considered. Recent data suggest AQPs and CFTR as attractive targets for drug development for therapy of keratoconjunctivitis sicca, recurrent corneal erosions, corneal edema, glaucoma, retinal detachment, and retinal ischemia.
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Affiliation(s)
- M H Levin
- Department of Medicine, Cardiovascular Research Institute, Graduate Group in Biophysics, University of California, San Francisco, CA 94143-0521, USA
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Mrugacz M, Zak J, Bakunowicz-Lazarczyk A, Wysocka J, Minarowska A. Flow cytometric analysis of HLA-DR antigen in conjunctival epithelial cells of patients with cystic fibrosis. Eye (Lond) 2006; 21:1062-6. [PMID: 16710427 DOI: 10.1038/sj.eye.6702435] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
PURPOSE Cystic fibrosis (CF) is an autosomal-recessive genetic disorder. The disease affects all secretory epithelia including the eye and belongs to the group of ocular surface epithelial diseases, termed keratoconjunctivitis sicca that develop in dry eye. In the pathogenesis of dry eye, inflammation plays a crucial role. The aim of this study was to investigate the expression of HLA-DR on conjunctival epithelial cells from patients with CF. MATERIALS AND METHODS Twenty-five patients with CF and 25 normal subjects underwent ocular examination. Tear film break-up time (TBUT), Schirmer test, lissamine green staining, and conjunctival impression cytology were carried out. Cells were processed for flow cytometry, by using monoclonal antibodies to HLA-DR. RESULTS The Schirmer test and TBUT scores were significantly lower in CF patients compared with controls. A significant increase of HLA-DR expression on epithelial cells was found in patients with CF compared with normal eyes. The Schirmer and TBUT test were positively correlated with HLA-DR expression for the percentage of cells. CONCLUSION These results suggest that conjunctival epithelial cells play an important proinflammatory role in ocular changes in CF patients. Our findings confirm the presence of an inflammatory background and the immune nature of this disease. HLA-DR measurement might be a useful method for monitoring of inflammatory processes in the conjunctiva and could be helpful in the use of anti-inflammatory drugs in the treatment of ocular findings in CF patients.
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Affiliation(s)
- M Mrugacz
- Department of Pediatric Ophthalmology Medical University of Bialystok, Bialystok, Poland.
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15
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Mrugacz M, Tobolczyk J, Minarowska A. Retinol binding protein status in relation to ocular surface changes in patients with cystic fibrosis treated with daily vitamin A supplements. Eur J Pediatr 2005; 164:202-6. [PMID: 15789254 DOI: 10.1007/s00431-004-1587-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2004] [Accepted: 10/22/2004] [Indexed: 11/26/2022]
Abstract
UNLABELLED Cystic fibrosis (CF) is an autosomal recessive disease characterised by increased viscosity of mucus secretions and high chloride concentration in exocrine secretions. Clinically, the patients suffer from chronic pulmonary changes, chronic pancreatic deficiency, and an obstruction of the gastrointestinal tract. The disease affects all secretory epithelia including the eye. The influence of nutritional status on long-term survival and quality of life of CF patients is well documented. Steatorrhea, a consequence of decreased fat digestion and absorption may be associated with vitamin deficiences, including vitamin A. The aim of this study was to document plasma retinol binding protein (RBP) status, a specific plasma transport protein for vitamin A, and ocular surface changes in children and adolescents with CF. The patients were recruited at the 3rd Department of Paediatric Diseases, Medical University of Bialystok, Poland. All patients were regularly seen by a CF specialist dietitian. A group of 15 patients had the following investigations: plasma RBP, visual acuity, physical examination, tear film break-up time, fluorescein staining and Schirmer tear test. A group of 15 age- and sex-matched controls without CF or ocular pathology were also recruited. Plasma RBP concentrations were significantly lower in patients with CF than in the control group. CF patients showed a statistically significant increase in the incidence of clinical blepharitis. Five of the CF patients had clinical evidence of dry eyes. CONCLUSION Low plasma retinol binding protein levels frequently occur in clinically stable and retinol supplemented cystic fibrosis patients, of whom five had dry eyes. We recommend monitoring of plasma retinol binding protein levels and evaluation of ocular surface changes, especially those with dry eye symptoms in all cystic fibrosis patients.
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Affiliation(s)
- Malgorzata Mrugacz
- Department of Paediatric Ophthalmology, Medical University of Bialystok, Washington Street 17, 15-274 Bialystok, Poland.
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Shiue MHI, Gukasyan HJ, Kim KJ, Loo DDF, Lee VHL. Characterization of cyclic AMP-regulated chloride conductance in the pigmented rabbit conjunctival epithelial cells. Can J Physiol Pharmacol 2002; 80:533-40. [PMID: 12117302 DOI: 10.1139/y02-066] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We have previously reported that the pigmented rabbit conjunctiva is a Cl- secreting tissue, subject to cAMP, Ca2+, and PKC modulation. The present study was conducted to characterize, at the cellular and molecular levels, cAMP-regulated Cl- channels in rabbit conjunctival epithelial cells. cAMP-inducible Cl- channel properties were evaluated by monitoring the whole-cell currents using patch clamp techniques. Results showed that 10 microM forskolin significantly stimulated a glibenclamide-inhibitable whole-cell conductance by approximately five-fold. Furthermore, reduction of the Cl- concentration in the bathing solution through partial substitution of NaCl with Na-isethionate resulted in a rightward shift of the reversal potential for both baseline and forskolin-stimulated whole-cell currents from 0 to values close to the theoretical Cl- reversal potential predicted by the Nernst equation. Western blot analysis with a monoclonal antibody recognizing the epitope in the C-terminus of the cystic fibrosis transmembrane conductance regulator (CFTR) showed a positive band at its molecular weight, approximately 170 kD. Immunostaining under confocal microscopy revealed a CFTR specific signal in the apical sections of primary conjunctival epithelial cells. In addition, RT-PCR detection amplified a cDNA fragment 100% identical to the predicted portion of the cloned rabbit CFTR message. The stage is thus set for determining the extent of CFTR contribution to cAMP-regulated Cl- conductance in pigmented rabbit conjunctival epithelial cells.
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Affiliation(s)
- Michael H I Shiue
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles 90089-9121, USA
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17
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Abstract
PURPOSE To investigate modifications of ocular surface and lens transparency in patients with cystic fibrosis in relation to the stage of digestive insufficiency. METHODS Forty consecutive patients with cystic fibrosis and 24 age- and sex-matched healthy volunteers were examined. The tear tests (Schirmer's basic test, tear film break-up time) and conjunctival exfoliative cytology (CC) were used to study the ocular surface. The lens transparency was measured with the Opacity Lens Meter 701 (OLM 701, Interzeag AG, Switzerland). Digestive insufficiency was evaluated by the steatocrit method. RESULTS Significant changes in conjunctival cytology and lens opacity, and abnormal tear tests were detected in CF patients; the alterations were more pronounced in patients with severe digestive insufficiency. CONCLUSIONS Cystic fibrosis patients present ocular surface abnormalities and lens transparency modifications and their severity is related to the digestive insufficiency. Simple, rapid and non-invasive tear tests and cytological procedures might be used as additional tests for assessing the severity of cystic fibrosis.
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Affiliation(s)
- I Castagna
- Institute of Ophthalmology, University of Messina, Italy
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Tsinopoulos I, Nousia-Arvanitakis S, Galli-Tsinopoulou A, Roubies N, Tentzidou K, Xefteri M, Stangos N. Role of electroretinography in the assessment of retinal function as an indicator of vitamin A status. Doc Ophthalmol 2000; 101:211-21. [PMID: 11291950 DOI: 10.1023/a:1002793728087] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Hypovitaminosis A is associated with exocrine pancreatic insufficiency in cystic fibrosis. Peripheral retinal dysfunction is an early finding of vitamin A deficiency. We evaluated serum retinol and zinc as well as visual adaptation in 41 patients with cystic fibrosis, receiving generous pancreatic enzyme and micronutrient supplementation. Forty-one normal individuals matched for age and sex served as controls. Peripheral retinal function was measured by clinical electroretinography using an Electrophysiologic Personal Interfaced Computer and applying a standard protocol. Serum retinol in cystic fibrosis was significantly lower than that of the control group (0.30+/-0.01 versus 0.39+/-0.02 mg/l, p<0.001). Serum zinc concentrations were normal in the cystic fibrosis group (1.21+/-0.03 mg/l) and significantly higher than that of the control group (1.02+/-0.01 mg/l, p<0.001). The overall visual adaptation, however, was found to be normal and comparable in the two groups. It is concluded that, in cystic fibrosis, despite appropriate vitamin A supplementation, retinol serum concentration may be low. As serum retinol does not reflect vitamin A status, evaluation of visual adaptation may be a more appropriate way to monitor for vitamin A deficiency in cystic fibrosis.
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Affiliation(s)
- I Tsinopoulos
- Department of Ophthalmology, Aristotle University of Thessaloniki, Greece.
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Kalayci D, Kiper N, Ozcelik U, Gocmen A, Hasiripi H. Clinical status, ocular surface changes and tear ferning in patients with cystic fibrosis. ACTA OPHTHALMOLOGICA SCANDINAVICA 1996; 74:563-5. [PMID: 9017042 DOI: 10.1111/j.1600-0420.1996.tb00735.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Twenty-three cystic fibrosis patients and 20 controls were examined for ocular surface changes and tear fluid ferning characteristics. The patients were also evaluated systemically and given numerical scores according to Schwachman's scoring system. Frequency of blepharitis, fluorescein staining, and the Schirmer's test values did not differ between patients and controls. Patients with cystic fibrosis had a higher frequency of altered ferning pattern that corresponded to the disease severity as measured by the Schwachman score (r = -0.48, p < 0.05). Although altered ferning pattern was frequent, the rate of type I ferning was also high (30%) in patients with cystic fibrosis. We conclude that the ferning test should not be used as an aid in diagnosis of cystic fibrosis but it may be used as an indicator of clinical status during follow-up.
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Affiliation(s)
- D Kalayci
- Numune Research and Training Hospital, Ankara, Turkey
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Morkeberg JC, Edmund C, Prause JU, Lanng S, Koch C, Michaelsen KF. Ocular findings in cystic fibrosis patients receiving vitamin A supplementation. Graefes Arch Clin Exp Ophthalmol 1995; 233:709-13. [PMID: 8566828 DOI: 10.1007/bf00164674] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
BACKGROUND Vitamin A deficiency with eye symptoms has been reported in patients with cystic fibrosis who received the recommended daily intake of vitamin A. METHODS We measured serum retinol, dark adaptation, contrast sensitivity, and dry eye status in 35 adult cystic fibrosis patients to ascertain whether they had ocular signs or symptoms. RESULTS Median serum retinol concentration was 1.95 mumol/l, range 1.08-4.01 mumol/l, with no values indicating vitamin A deficiency. Retinal light sensitivity was normal. Nineteen patients had reduced contrast sensitivity. Conjunctival imprints all showed plenty of goblet cells, but were characteristic of dry eye in 42% of patients (n = 14). Decreased tear film stability was found in 49% (n = 17), tear production was low in 31% (n = 11), and 23% (n = 8) showed an increased amount of dying epithelial cells. Nine patients (26%) had keratoconjunctivitis sicca according to the Copenhagen criteria. CONCLUSION Our patients had no biochemical or clinical signs of vitamin A deficiency. We speculate that the high incidence of dry eye could be a primary manifestation of cystic fibrosis.
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Affiliation(s)
- J C Morkeberg
- Department of Pediatrics, Cystic Fibrosis Center, State University Hospital, Copenhagen, Denmark
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