The cornea is the primary refractive element of the eye and therefore it must be smooth and transparent for good vision. Transparency is most affected by the hydration level of the stromal connective tissue. Hydration is dependent on the metabolic activities of the corneal epithelium and endothelium;however it is the endothelium that is primarily responsible for pumping ions and fluid that maintains the steady-state hydration of the stroma. The long-term goal of this project is to understand how the corneal endothelium does this job, so that medical therapies can be developed to enhance endothelial function in corneas that have been compromised by disease or trauma. The endothelial ion and fluid pump is most dependent on HCOa"""""""" for its function. Our approach has been to identify, characterize, and integrate the membrane pumps, transporters and channels into a model for transendothelial HCCV and fluid transport in a cultured endothelial cell system. In this period of the project we focus on understanding the mechanisms for apical HCOa'efflux, particularly the roles of carbonic anhydrases (CAs) and anion exchangers and how they may buffer and facilitate the transport of lactic acid. To do this, we will identify and localize lactate: H+ cotransporters and determine if lactate fluxes are reduced by pharmacological inhibitors for CAs and HCO3"""""""" transporters as well as following treatment with small interfering RNA to reduce CA or transporter expression. We also examine the roles of adenosine receptor stimulation and soluble adenylyl cyclase in setting cell [cAMP], which has a stimulatory effect on endothelial function. This will also use the siRNA approach and examine cAMP/PKA mediated phosphorylation of transporters, myosin light chain, and CREB transcription factor as well as the effects on net HCO3"""""""" transport as measures of relative PKA activity. Lastly, we will examine the model of HCOa"""""""" transport that is being built in vitro with cultured cells in the in vivo rabbit cornea. Our approach is to use lentiviral delivery of interfering RNA molecules to reduce specific transporter expression in vivo and examine the effect on corneal thickness and endothelial function. The results from this Aim will tell us the relative importance of the various transporters in maintaining corneal hydration in the in vivo cornea.

Agency
National Institute of Health (NIH)
Institute
National Eye Institute (NEI)
Type
Research Project (R01)
Project #
5R01EY008834-20
Application #
8035354
Study Section
Special Emphasis Panel (ZRG1-BDCN-F (02))
Program Officer
Mckie, George Ann
Project Start
1991-07-01
Project End
2012-03-31
Budget Start
2011-03-01
Budget End
2012-03-31
Support Year
20
Fiscal Year
2011
Total Cost
$323,968
Indirect Cost
Name
Indiana University Bloomington
Department
Type
Schools of Optometry/Ophthalmol
DUNS #
006046700
City
Bloomington
State
IN
Country
United States
Zip Code
47401
Bhadange, Yogesh; Lautert, Jeferson; Li, Shimin et al. (2018) Hypoxia and the Prolyl Hydroxylase Inhibitor FG-4592 Protect Corneal Endothelial Cells From Mechanical and Perioperative Surgical Stress. Cornea 37:501-507
Li, Shimin; Hundal, Karmjot Singh; Chen, Xingjuan et al. (2018) R125H, W240S, C386R, and V507I SLC4A11 mutations associated with corneal endothelial dystrophy affect the transporter function but not trafficking in PS120 cells. Exp Eye Res 180:86-91
Zhang, Wenlin; Ogando, Diego G; Kim, Edward T et al. (2017) Conditionally Immortal Slc4a11-/- Mouse Corneal Endothelial Cell Line Recapitulates Disrupted Glutaminolysis Seen in Slc4a11-/- Mouse Model. Invest Ophthalmol Vis Sci 58:3723-3731
Zhang, Wenlin; Li, Hongde; Ogando, Diego G et al. (2017) Glutaminolysis is Essential for Energy Production and Ion Transport in Human Corneal Endothelium. EBioMedicine 16:292-301
Li, Shimin; Kim, Edward; Bonanno, Joseph A (2016) Fluid transport by the cornea endothelium is dependent on buffering lactic acid efflux. Am J Physiol Cell Physiol 311:C116-26
Zhang, Wenlin; Ogando, Diego G; Bonanno, Joseph A et al. (2015) Human SLC4A11 Is a Novel NH3/H+ Co-transporter. J Biol Chem 290:16894-905
Li, Shimin; Nguyen, Tracy T; Bonanno, Joseph A (2014) CD147 required for corneal endothelial lactate transport. Invest Ophthalmol Vis Sci 55:4673-81
Robertson, Danielle M; Alexander, Larry J; Bonanno, Joseph A et al. (2014) Cornea and ocular surface disease: application of cutting-edge optometric research. Optom Vis Sci 91:S3-16
Jalimarada, Supriya S; Ogando, Diego G; Bonanno, Joseph A (2014) Loss of ion transporters and increased unfolded protein response in Fuchs' dystrophy. Mol Vis 20:1668-79
Jalimarada, Supriya S; Ogando, Diego G; Vithana, Eranga N et al. (2013) Ion transport function of SLC4A11 in corneal endothelium. Invest Ophthalmol Vis Sci 54:4330-40

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