This project will study fibroblast differentiation during specialization of connective tissues, concentrating especially on differentiation of keratocytes of the corneal stroma from the neural crest population of embryonic progenitor cells in the head region, versus differentiation of fibroblasts in other ocular and non-ocular tissues. Markers of keratocyte differentiation are ability to synthesize the three major keratan sulfate proteoglycan (KSPG) core proteins (lumican, keratocan, KSPG 25 or mimican) and glycosylate them with long, highly sulfated chains of keratan sulfate (KS). Such """"""""KSylation"""""""" is a unique feature of corneal KSPGs and of neural crest/fibroblast differentiation into keratocytes.
Specific Aims are to: 1) Determine if alternative splicing occurs during biosynthesis of the 3 KSPG core proteins in corneal keratocytes and in other fibroblastic and connective tissue cells in the eye and head regions; 2) Identify regulatory elements in genomic DNA that control biosynthesis of KSPGs in corneal keratocytes; 3) Identify factors that regulate glycosylation and sulfation of the three KSPG core proteins in the cornea and other tissues; 4) Characterize the expression patterns of the KSPG mRNAs and core proteins during corneal development, particularly in relation to timing and pattern of corneal innervation; 5) Determine the origin of corneal nerves - neural crest vs. ectodermal placode; 6) Determine the effect on corneal development and innervation of perturbing the biosynthesis of 1, 2, or all 3 corneal KSPGs; and 7) Determine if receptors for KSPGs occur on corneal cell types, as demonstrated on macrophages. Molecular biology methods will be applied to tissues from adult bovine eyes, as well as from those of quail and chicken embryos. Standard biochemical methods for proteoglycans, sugars, and sulfate ions will be used to focus on KSPGs as sensitive markers of keratocyte differentiation. Although transplanted corneas generally remain transparent re-innervation of the graft is very slow (years) and incomplete, depriving patients of corneal touch sensitivity. Research proposed may elucidate a relationship between KSPG distribution and pathways chosen by corneal nerves that mainly arise from the trigeminal ganglion.

Agency
National Institute of Health (NIH)
Institute
National Eye Institute (NEI)
Type
Research Project (R01)
Project #
2R01EY000952-27
Application #
2559059
Study Section
Visual Sciences A Study Section (VISA)
Project Start
1988-08-01
Project End
2003-03-31
Budget Start
1998-04-01
Budget End
1999-03-31
Support Year
27
Fiscal Year
1998
Total Cost
Indirect Cost
Name
Kansas State University
Department
Biology
Type
Schools of Arts and Sciences
DUNS #
City
Manhattan
State
KS
Country
United States
Zip Code
66506
Mao, Xiuli; Zhang, Yuntao; Schwend, Tyler et al. (2015) Effects of polysialic acid on sensory innervation of the cornea. Dev Biol 398:193-205
Zhang, Yuntao; Mao, Xiuli; Schwend, Tyler et al. (2013) Resistance of corneal RFUVA–cross-linked collagens and small leucine-rich proteoglycans to degradation by matrix metalloproteinases. Invest Ophthalmol Vis Sci 54:1014-25
Schwend, Tyler; Lwigale, Peter Y; Conrad, Gary W (2012) Nerve repulsion by the lens and cornea during cornea innervation is dependent on Robo-Slit signaling and diminishes with neuron age. Dev Biol 363:115-27
Schwend, Tyler; Deaton, Ryan J; Zhang, Yuntao et al. (2012) Corneal sulfated glycosaminoglycans and their effects on trigeminal nerve growth cone behavior in vitro: roles for ECM in cornea innervation. Invest Ophthalmol Vis Sci 53:8118-37
Littlechild, Stacy L; Zhang, Yuntao; Tomich, John M et al. (2012) Fibrinogen, riboflavin, and UVA to immobilize a corneal flap--molecular mechanisms. Invest Ophthalmol Vis Sci 53:5991-6003
Zhang, Guodong; Boyle, Daniel L; Zhang, Yuntao et al. (2012) Development and mineralization of embryonic avian scleral ossicles. Mol Vis 18:348-61
Littlechild, Stacy L; Brummer, Gage; Zhang, Yuntao et al. (2012) Fibrinogen, riboflavin, and UVA to immobilize a corneal flap--conditions for tissue adhesion. Invest Ophthalmol Vis Sci 53:4011-20
Zhang, Yuntao; Sukthankar, Pinakin; Tomich, John M et al. (2012) Effect of the synthetic NC-1059 peptide on diffusion of riboflavin across an intact corneal epithelium. Invest Ophthalmol Vis Sci 53:2620-9
Brummer, Gage; Littlechild, Stacy; McCall, Scott et al. (2011) The role of nonenzymatic glycation and carbonyls in collagen cross-linking for the treatment of keratoconus. Invest Ophthalmol Vis Sci 52:6363-9
Zhang, Yuntao; Conrad, Abigail H; Conrad, Gary W (2011) Effects of ultraviolet-A and riboflavin on the interaction of collagen and proteoglycans during corneal cross-linking. J Biol Chem 286:13011-22

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