Inhibitions of Chloride Transport and Gap Junction Reduce Fluid Flow across the Whole Porcine Ciliary Epithelium

Law, C.S.; Candia, Oscar A.; To, Chi‐Ho

doi:10.1167/iovs.08-1888

Cited by 6 publications

(12 citation statements)

References 30 publications

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“…5,6,[19][20][21] Recently, we have demonstrated that the stimulation of Isc by cAMP and forskolin in porcine CE 22 are in good agreement with results obtained in human tissue. 23 In this study, we aimed to characterize the expression of Cx isoforms in porcine CE, determine the relative abundance of various Cx, and investigate the functional significance of the most abundant Cx in mediating fluid movement from PE to NPE cells.…”

supporting

confidence: 81%

“…Based on the results of gene and protein expressions, together with the previous findings showing the crucial role of gap junctions between PE and NPE cells in regulating AH secretion, 6,7 we speculated whether Cx43 was important in transferring fluid from PE to NPE cells leading to AH formation in pigs. To test this hypothesis, we used small interfering RNA (siRNA) to knockdown the expression of Cx43 and determined whether it affected the fluid movement across isolated porcine PE-NPE cell couplets by using the LY dye transfer technique.…”

Section: Effect Of Cx43 Knockdown On Dye Transfermentioning

confidence: 83%

“…5 More importantly, heptanol has been demonstrated to elicit direct inhibition of transepithelial fluid transport across intact CE by~80%. 6 The inhibitory effect is possibly mediated by the uncoupling of gap junctions (i.e., decrease in junctional currents and gap junction permeability) between PE and NPE cells. 7 Generally, gap junction channels aggregate on the plasma membrane where they facilitate intercellular communication by exchanging solutes, metabolites, and signaling messengers between adjacent cells.…”

mentioning

confidence: 99%

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Characterization and Regulation of Gap Junctions in Porcine Ciliary Epithelium

Shan

et al. 2018

Invest. Ophthalmol. Vis. Sci.

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PURPOSE. Gap junctions provide a conduit between the intracellular fluids of the pigmented (PE) and non-pigmented (NPE) ciliary epithelial cells, and are therefore critical in the secretion of the aqueous humor (AH). However, opinions differ concerning the connexin (Cx) composition of the gap junctions. Therefore, we aimed to characterize the expression of Cx in the porcine ciliary epithelium (CE), a favorable model for humans; and determine the contribution of the highest expressed Cx to AH secretion. METHODS.Freshly-harvested porcine CE cells were used. The mRNA and protein expressions of gap junctions were assessed by reverse transcription polymerase chain reaction (RT-PCR) and Western blotting (WB), respectively. The relative gene expressions of various Cx were determined by quantitative PCR. The gap junction permeability of isolated PE-NPE cell couplets was evaluated by Lucifer Yellow dye transfer.RESULTS. Using RT-PCR and WB, Cx43, Cx45, Cx47, Cx50, and Cx60 were present in porcine CE, with Cx43 being the most abundant isoform, having over 200-fold higher expression than other Cx. Cx43 was primarily localized in the PE-NPE interface and the basolateral membranes of PE cells. Knockdown of Cx43 by siRNA significantly reduced gene and protein expressions, resulting in reduction of transcellular fluid flow by 90%.CONCLUSIONS. Cx43 was found to be the major component of gap junctions in porcine CE. Consistent with results from a bovine model, our results support the important role of Cx43 in mediating AH secretion. This finding may shed light on the development of a novel ocular hypotensive agent.

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supporting

confidence: 81%

Section: Effect Of Cx43 Knockdown On Dye Transfermentioning

confidence: 83%

mentioning

confidence: 99%

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Characterization and Regulation of Gap Junctions in Porcine Ciliary Epithelium

Shan

et al. 2018

Invest. Ophthalmol. Vis. Sci.

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“…Because P2Y 6 receptor activation causes TGFβ production (59, 60), UDP may suppress Cl -secretion by producing both TGFβ and cAMP. Another possible candidate is the gap junction because it mediates intercellular connections between PE and NPE cells, which is essential for transepithelial Cl -transport (56,61). Elevation of cAMP caused intercellular uncoupling between PE and NPE cells (56 ]i.…”

Section: Discussionmentioning

confidence: 99%

Purinergic dysregulation causes hypertensive glaucoma–like optic neuropathy

Shinozaki¹,

Kashiwagi²,

Namekata³

et al. 2017

JCI Insight

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“…Fresh bovine corneas with the epithelium scrapped off were used as positive control. Each side of the chamber was filled with Ringer's buffer solution (pH 7.4) [30].…”

Section: Functional Testsmentioning

confidence: 99%

Bovine Posterior Limbus: An Evaluation of an Alternative Source for Corneal Endothelial and Trabecular Meshwork Stem/Progenitor Cells

Grierson

Sheridan

et al. 2015

Stem Cells and Development

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A growing body of evidence has revealed that stem-like cells in the posterior limbus of the eye between the corneal endothelium (CE) and trabecular meshwork (TM) may be able to rejuvenate these tissues in disease. However, these cells have not been clearly defined and we have named them PET cells (progenitor cells of the endothelium and trabeculum). A good and inexpensive animal model for PET cells is lacking, so we investigated bovine eyes as an effective large tissue source. We showed the presence of stem/progenitor cells in the bovine CE, transition zone, and TM in situ. Floating spheres cultured from the CE and TM showed similar stem cell marker expression patterns. Both the CE and TM spheres were bipotent and highly proliferative, but with limited secondary sphere-forming capability. They were highly prone to differentiate back into the cell type of their tissue of origin. It is speculated that the PET cells become more tissue-specific as they migrate away from their niche. Here, we showed that PET cells are present in the posterior limbus of bovine eyes and that they can be successfully cultured and expanded. PET cells represent an attractive target for developing new treatments to regenerate both the CE and TM, thereby reducing the requirement for donor tissue for corneal transplant and invasive treatments for glaucomatous patients.

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Inhibitions of Chloride Transport and Gap Junction Reduce Fluid Flow across the Whole Porcine Ciliary Epithelium

Cited by 6 publications

References 30 publications

Characterization and Regulation of Gap Junctions in Porcine Ciliary Epithelium

Characterization and Regulation of Gap Junctions in Porcine Ciliary Epithelium

Purinergic dysregulation causes hypertensive glaucoma–like optic neuropathy

Bovine Posterior Limbus: An Evaluation of an Alternative Source for Corneal Endothelial and Trabecular Meshwork Stem/Progenitor Cells

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