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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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Hirata H, Mizerska K, Marfurt CF, Rosenblatt MI. Hyperosmolar Tears Induce Functional and Structural Alterations of Corneal Nerves: Electrophysiological and Anatomical Evidence Toward Neurotoxicity. Invest Ophthalmol Vis Sci 2016; 56:8125-40. [PMID: 26720465 DOI: 10.1167/iovs.15-18383] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE In an effort to elucidate possible neural mechanisms underlying diminished tearing in dry eye disease, this study sought to determine if hyperosmolar tears, a ubiquitous sign of dry eye disease, produce functional changes in corneal nerve responses to drying of the cornea and if these changes correlate with alterations in corneal nerve morphology. METHODS In vivo extracellular electrophysiological recordings were performed in rat trigeminal ganglion neurons that innervated the cornea before, and up to 3 hours after, the ocular application of continuous hyperosmolar tears or artificial tears. In corollary experiments, immunohistochemical staining was performed to compare corneal nerve morphology in control and in eyes treated with hyperosmolar solutions. RESULTS Our previous studies identified a population of corneal afferents, dry-sensitive neurons that are strongly excited by corneal dessication ("dry response"), a response thought to trigger the lacrimation reflex. In the present study, we found that the dry responses of corneal dry-sensitive neurons were depressed or even completely abolished by hyperosmolar tears in a time- (30 minutes to 3 hours) and dose (450- to 1000-mOsm solutions)-dependent manner. Furthermore, eyes treated with hyperosmolar tears for 3 hours contained large numbers of morphologically abnormal (granular, fragmented, or prominently beaded) subbasal nerves that appeared to be undergoing degeneration. CONCLUSIONS These results demonstrate that tear hyperosmolarity, considered to be a "core" mechanism of dry eye disease, significantly decreases physiological sensitivity and morphologic integrity of the corneal nerves important in tear production. These alterations might contribute to the diminished tearing seen clinically in dry eye patients.
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Affiliation(s)
- Harumitsu Hirata
- Department of Ophthalmology Weill Cornell Medical College, New York, New York, United States
| | - Kamila Mizerska
- Department of Ophthalmology Weill Cornell Medical College, New York, New York, United States
| | - Carl F Marfurt
- Department of Anatomy and Cell Biology, Indiana University School of Medicine-Northwest, Gary, Indiana, United States
| | - Mark I Rosenblatt
- Department of Ophthalmology and Visual Science, University of Illinois College of Medicine, Chicago, Illinois, United States
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Sivasankar M, Erickson E, Rosenblatt M, Branski RC. Hypertonic challenge to porcine vocal folds: effects on epithelial barrier function. Otolaryngol Head Neck Surg 2009; 142:79-84. [PMID: 20096227 DOI: 10.1016/j.otohns.2009.09.011] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2009] [Revised: 08/31/2009] [Accepted: 09/18/2009] [Indexed: 10/20/2022]
Abstract
OBJECTIVE Dehydration challenges can increase the chemical composition of surface fluid overlying vocal fold epithelia (hypertonic surface fluid). The vocal fold epithelium is posited to act as a barrier, shielding the lamina propria from perturbations in the airway lumen. However, the effects of hypertonic surface fluid on the barrier functions of vocal fold epithelia have not been quantified. We, therefore, sought to investigate whether hypertonic surface fluid compromises epithelial barrier function. We examined the effects of hypertonic surface fluid on vocal fold epithelial resistance, paracellular pathway morphology, and tight junction protein integrity. STUDY DESIGN Ex vivo, between group design. SETTING Laboratory. METHODS Porcine vocal folds (n = 24) were exposed to hypertonic or isotonic challenge and examined by electrophysiology, transmission electron microscopy, and Western blot analyses. RESULTS Hypertonic, but not isotonic, challenge significantly reduced transepithelial resistance. This decrease in resistance was observed immediately after the challenge and was consistent with the appearance of dilated paracellular pathway morphology. However, hypertonic challenge did not alter protein levels of occludin, zona occludens-1, E-cadherin, or beta-catenin. CONCLUSION Hypertonic surface fluid alters epithelial barrier function in the vocal folds. Specifically, exposure to hypertonic challenges increases epithelial permeability. Given the important role of the vocal fold epithelium in shielding the underlying mucosa from inhaled pathogens and pollutants, our data provide the impetus for future studies on pharmacological treatments aimed at restoring the hydration level and chemical composition of vocal fold surface fluid.
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Affiliation(s)
- Mahalakshmi Sivasankar
- Department of Speech, Language, and Hearing Sciences, Purdue University, West Lafayette, IN, USA.
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Ste20-related proline/alanine-rich kinase (SPAK) regulated transcriptionally by hyperosmolarity is involved in intestinal barrier function. PLoS One 2009; 4:e5049. [PMID: 19343169 PMCID: PMC2660421 DOI: 10.1371/journal.pone.0005049] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2009] [Accepted: 02/06/2009] [Indexed: 01/01/2023] Open
Abstract
The Ste20-related protein proline/alanine-rich kinase (SPAK) plays important roles in cellular functions such as cell differentiation and regulation of chloride transport, but its roles in pathogenesis of intestinal inflammation remain largely unknown. Here we report significantly increased SPAK expression levels in hyperosmotic environments, such as mucosal biopsy samples from patients with Crohn's disease, as well as colon tissues of C57BL/6 mice and Caco2-BBE cells treated with hyperosmotic medium. NF-kappaB and Sp1-binding sites in the SPAK TATA-less promoter are essential for SPAK mRNA transcription. Hyperosmolarity increases the ability of NF-kappaB and Sp1 to bind to their binding sites. Knock-down of either NF-kappaB or Sp1 by siRNA reduces the hyperosmolarity-induced SPAK expression levels. Furthermore, expression of NF-kappaB, but not Sp1, was upregulated by hyperosmolarity in vivo and in vitro. Nuclear run-on assays showed that hyperosmolarity increases SPAK expression levels at the transcriptional level, without affecting SPAK mRNA stability. Knockdown of SPAK expression by siRNA or overexpression of SPAK in cells and transgenic mice shows that SPAK is involved in intestinal permeability in vitro and in vivo. Together, our data suggest that SPAK, the transcription of which is regulated by hyperosmolarity, plays an important role in epithelial barrier function.
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Iskeleli G, Karakoc Y, Abdula A. Tear film osmolarity in patients with thyroid ophthalmopathy. Jpn J Ophthalmol 2008; 52:323-326. [DOI: 10.1007/s10384-008-0545-7] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2007] [Accepted: 02/22/2008] [Indexed: 11/24/2022]
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Luo L, Li DQ, Pflugfelder SC. Hyperosmolarity-induced apoptosis in human corneal epithelial cells is mediated by cytochrome c and MAPK pathways. Cornea 2007; 26:452-60. [PMID: 17457195 DOI: 10.1097/ico.0b013e318030d259] [Citation(s) in RCA: 105] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
PURPOSE To study whether hyperosmolarity induces apoptosis in human corneal epithelial cells through cytochrome c-mediated death pathways and by activation of mitogen-activated protein kinases (MAPKs). METHODS Primary human corneal epithelial cells cultured in normal osmolar media (312 mOsM) were switched to hyperosmolar media (450, 500, and 550 mOsM) by adding 70, 90, and 120 mM NaCl, respectively, with or without the c-jun N-terminal kinase (JNK) inhibitor SB202190 or the extracellular-regulated kinase (ERK) inhibitor PD98059. Apoptosis was assessed by the ApopTag In Situ Oligo Ligation (ISOL) assay. Confocal microscopy was used to detect cytochrome c and active caspase-3. Total RNA was extracted and subjected to reverse transcriptase-polymerase chain reaction for apoptosis-associated genes. Western blots were performed on cell extracts for the apoptogenic molecules cytochrome c and Smac/DIABLO, and phospho-JNK and ERK. RESULTS ISOL-positive apoptotic cells significantly increased from 3.3 +/- 1.6% in control medium to 11.4 +/- 5.8%, 18.9 +/- 4.8%, and 43.9 +/- 8.8% in 70, 90, and 120 mM NaCl added media, respectively. The 90 mM NaCl high saline medium notably increased release of cytochrome c and Smac/DIABLO from mitochondria; activated caspase-3, JNK and ERK; stimulated mRNA expression of interleukin-1-converting enzyme and Bax; and reduced Bcl2 expression. SB202190 and PD98059 significantly suppressed hyperosmolarity-induced JNK/ERK activation and ISOL-positive cells. In addition, PD98059 inhibited the release of cytochrome c and Smac/DIABLO from mitochondria. CONCLUSIONS These findings show that hyperosmolarity induces apoptosis of human corneal epithelial cells through a cytochrome c-mediated death pathway, which may be mediated by JNK and ERK MAPK signaling pathways.
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Affiliation(s)
- Lihui Luo
- Ocular Surface Center, Cullen Eye Institute, Department of Ophthalmology, Baylor College of Medicine, Houston, TX 77030, USA
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Begley CG, Himebaugh N, Renner D, Liu H, Chalmers R, Simpson T, Varikooty J. Tear Breakup Dynamics: A Technique for Quantifying Tear Film Instability. Optom Vis Sci 2006; 83:15-21. [PMID: 16432468 DOI: 10.1097/01.opx.0000195569.36185.fd] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
PURPOSE The purpose of this study was to develop a novel, quantitative measurement of tear film breakup dynamics (TBUD) to study the phenomenon of tear breakup in dry eye and control subjects and its impact on dry eye symptoms. METHODS Ten control and 10 dry eye subjects completed the Dry Eye (DEQ) and other questionnaires. After the instillation of sodium fluorescein, subjects kept the tested eye open for as long as possible, similar to a staring contest, while tear film breakup was videotaped (S-TBUD). The maximum blink interval (MBI) and tear breakup time (TBUT) were measured from digital movies by a masked observer. Individual frames of movies were converted to gray-scale images, maps of relative tear film fluorescence were generated, and the total area of tear breakup (AB) of the exposed cornea was quantified. RESULTS On average, dry eye subjects demonstrated a higher AB and shorter TBUT and MBI, but only the AB was significantly different (p = 0.023). Subjects most often used the descriptors stinging and burning to describe their sensations during staring trials. The AB showed a high correlation between eyes and with some DEQ symptom measures. CONCLUSIONS These methods allow objective quantification and tracking of the phenomenon of tear breakup. Our results suggest that tear breakup stresses the corneal surface, resulting in stimulation of underlying nociceptors. The tear film of dry eye subjects was less stable than controls. They had a larger AB measured from the last video frame before MBI (i.e., just before blinking) than did controls. This perhaps reflects adaptation to the repeated stress of tear instability in dry eye.
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Affiliation(s)
- Carolyn G Begley
- Indiana University School of Optometry, 800 E. Atwater Street, Bloomington, IN 47405, USA.
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Li DQ, Luo L, Chen Z, Kim HS, Song XJ, Pflugfelder SC. JNK and ERK MAP kinases mediate induction of IL-1beta, TNF-alpha and IL-8 following hyperosmolar stress in human limbal epithelial cells. Exp Eye Res 2005; 82:588-96. [PMID: 16202406 PMCID: PMC2198933 DOI: 10.1016/j.exer.2005.08.019] [Citation(s) in RCA: 257] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2005] [Revised: 08/18/2005] [Accepted: 08/19/2005] [Indexed: 10/25/2022]
Abstract
Hyperosmolarity has been recognized to be a pro-inflammatory stress to the corneal epithelium. The cell signalling pathways linking hyperosmolar stress and inflammation have not been well elucidated. This study investigated whether exposure of human limbal epithelial cells to hyperosmotic stress activates the mitogen-activated protein kinase (MAPK) pathways and induces production of pro-inflammatory cytokines, interleukin (IL) -1beta, tumor necrosis factor (TNF) alpha, and the C-X-C chemokine IL-8. Primary human limbal epithelial cultures in normal osmolar media (312 mOsM) were exposed to media with higher osmolarity (400-500 mOsM) by adding 50-90 mM NaCl, with or without SB202190, an inhibitor of c-Jun N-terminal kinases (JNK) pathway, PD 98059, an inhibitor of extracellular-regulated kinase (ERK) pathway, dexamethasone or doxycycline for different lengths of time. The conditioned media were collected after 24 hr of treatment for ELISA. Total RNA was extracted from cultures treated for 6 hr for semi-quantitative RT-PCR. Cells treated for 15-60 min were lysed in RIPA buffer and subjected to Western blot with phospho (p)-specific antibodies against p-JNK and p-ERK. The concentrations of IL-1beta, TNF-alpha and IL-8 proteins in 24 hr conditioned media of limbal epithelial cells progressively increased as the media osmolarity increased from 312 to 500 mOsM. Active p-JNK-1/p-JNK-2 and p-ERK-1/p-ERK-2 were detected by Western blot and peaked at 60 min in cells exposed to hyperosmolar media. The levels of p-JNK-1/p-JNK-2 and p-ERK1/p-ERK2 were positively correlated with the medium osmolarity. SB202190, PD98059 and doxycycline markedly suppressed the levels of p-JNK-1/p-JNK-2 and/or p-ERK1/p-ERK2, as well as IL-1beta, TNF-alpha and IL-8 mRNAs and proteins stimulated by hyperosmolar media. These findings provide direct evidence that hyperosmolarity induces inflammation in human limbal epithelial cells by increasing expression and production of pro-inflammatory cytokines and chemokines, a process that appears to be mediated through activation of the JNK and ERK MAPK signalling pathways. The efficacy of doxycycline in treating ocular surface diseases may be due to its ability to suppress JNK and ERK signalling activation and inflammatory mediator production in the limbal epithelium.
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Affiliation(s)
- De-Quan Li
- Ocular Surface Center, Cullen Eye Institute, Department of Ophthalmology, Baylor College of Medicine, 6565 Fannin Street, NC-205, Houston, TX 77030, USA
| | - Lihui Luo
- Ocular Surface Center, Cullen Eye Institute, Department of Ophthalmology, Baylor College of Medicine, 6565 Fannin Street, NC-205, Houston, TX 77030, USA
| | - Zhuo Chen
- Ocular Surface Center, Cullen Eye Institute, Department of Ophthalmology, Baylor College of Medicine, 6565 Fannin Street, NC-205, Houston, TX 77030, USA
| | - Hyun-Seung Kim
- Ocular Surface Center, Cullen Eye Institute, Department of Ophthalmology, Baylor College of Medicine, 6565 Fannin Street, NC-205, Houston, TX 77030, USA
- Department of Ophthalmology, College of Medicine, The Catholic University of Korea, South Korea
| | - Xiu Jun Song
- Ocular Surface Center, Cullen Eye Institute, Department of Ophthalmology, Baylor College of Medicine, 6565 Fannin Street, NC-205, Houston, TX 77030, USA
- Third Hospital of Hebei Medical University, Shijiazhuang, China
| | - Stephen C Pflugfelder
- Ocular Surface Center, Cullen Eye Institute, Department of Ophthalmology, Baylor College of Medicine, 6565 Fannin Street, NC-205, Houston, TX 77030, USA
- * Corresponding author. Address: Dr. Stephen C. Pflugfelder, Ocular Surface Center, Cullen Eye Institute, Department of Ophthalmology, Baylor College of Medicine, 6565 Fannin Street, NC-205, Houston, TX 77030, USA. E-mail address: (S.C. Pflugfelder)
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Luo L, Li DQ, Corrales RM, Pflugfelder SC. Hyperosmolar Saline Is a Proinflammatory Stress on the Mouse Ocular Surface. Eye Contact Lens 2005; 31:186-93. [PMID: 16163009 DOI: 10.1097/01.icl.0000162759.79740.46] [Citation(s) in RCA: 236] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
PURPOSE To investigate whether hyperosmolar stress stimulates production of inflammatory mediators and activates the mitogen-activated protein kinase (MAPK) signaling pathways, c-jun n-terminal kinases (JNKs), extracellular-regulated kinases (ERKs), and p38 on the mouse ocular surface. METHODS 129SvEv/CD-1 mixed mice were treated with a balanced salt solution (BSS) (305 mOsM) or a hyperosmotic saline solution (HOSS) (500 mOsM). Untreated age-matched mice were used as controls. The concentrations of interleukin 1beta (IL-1beta) and tumor necrosis factor alpha (TNF-alpha) were measured by enzyme-linked immunosorbent assay. Gelatinase activity was determined by in situ zymography. Corneal and conjunctival epithelia were lysed for Western blot with MAPK antibodies or used for semiquantitative reverse transcription and polymerase chain reaction and gene array. RESULTS Compared with age-matched controls and mice treated with BSS, the concentration of IL-1beta in tear fluid washings and the concentrations of IL-1beta and TNF-alpha and gelatinolytic activity in the corneal and conjunctival epithelia were significantly increased in mice treated with HOSS for 2 days. The expressions of IL-1beta, TNF-alpha, and matrix metalloproteinase 9 (MMP-9) messenger RNA by the corneal and conjunctival epithelia were also notably stimulated in mice treated with HOSS. The levels of phosphorylated JNK1/2, ERK1/2, and p38 MAPKs in the corneal and conjunctival epithelia were slightly increased in mice treated with BSS, but markedly increased in mice treated with HOSS. CONCLUSIONS These results show that the hyperosmolarity stimulates expression and production of IL-1beta, TNF-alpha, and MMP-9 and activates JNK, ERK, and p38 MAPK signaling pathways on the mouse ocular surface. These findings suggest that hyperosmolar stress, as it may occur in dry eye, promotes ocular surface inflammation.
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Affiliation(s)
- Lihui Luo
- Ocular Surface Center, Cullen Eye Institute, Department of Ophthalmology, Baylor College of Medicine, Houston, TX 77030, USA
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