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. 2013 Oct 30:19:2124-34.
eCollection 2013.

Preliminary identification of differentially expressed tear proteins in keratoconus

Sivaraman A Balasubramanian  1 , Valerie C Wasinger, David C Pye, Mark D P Willcox
Affiliations

Preliminary identification of differentially expressed tear proteins in keratoconus

Sivaraman A Balasubramanian et al. Mol Vis. .

Abstract

Purpose: To examine the proteins differentially expressed in the tear film of people with keratoconus and normal subjects.

Methods: Unstimulated tears from people with keratoconus (KC) and controls (C) were collected using a capillary tube. Tear proteins from people with KC and controls were partitioned using a novel in-solution electrophoresis, Microflow 10 (ProteomeSep), and analyzed using linear ion trap quadrupole fourier transform mass spectrometry. Spectral counting was used to quantify the individual tear proteins.

Results: Elevated levels of cathepsin B (threefold) were evident in the tears of people with KC. Polymeric immunoglobulin receptor (ninefold), fibrinogen alpha chain (eightfold), cystatin S (twofold), and cystatin SN (twofold) were reduced in tears from people with KC. Keratin type-1 cytoskeletal-14 and keratin type-2 cytoskeletal-5 were present only in the tears of people with KC.

Conclusions: The protein changes in tears, that is, the decrease in protease inhibitors and increase in proteases, found in the present and other previously published studies reflect the pathological events involved in KC corneas. Further investigations into tear proteins may help elucidate the underlying molecular mechanisms of KC, which could result in better treatment options.

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Figures

Figure 1
Figure 1
Schematic diagram showing the workflow to analyze tear proteins in the present study.
Figure 2
Figure 2
The Microflow 10 separation system, modified from Ly et al. [42]. F represents fraction.
Figure 3
Figure 3
Altered tear protein levels. A: Protein that was increased in abundance in tears from people with keratoconus (KC) compared to the controls. B-E: Proteins that were decreased in abundance in tears from people with KC compared to the controls.
Figure 4
Figure 4
Ontology analysis of tear proteins. A: Cellular compartments of the proteins altered in tears from people with keratoconus (KC). B: Probable role in biologic processes of the proteins altered in tears from people with KC. C: Functions of the proteins altered in tears from people with KC.
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References

    1. de Souza GA, Godoy LM, Mann M. Identification of 491 proteins in the tear fluid proteome reveals a large number of proteases and protease inhibitors. Genome Biol. 2006;7:R72. - PMC - PubMed
    1. Kao WW, Vergnes JP, Ebert J, Sundar-Raj CV, Brown SI. Increased collagenase and gelatinase activities in keratoconus. Biochem Biophys Res Commun. 1982;107:929–36. - PubMed
    1. Rehany U, Lahav M, Shoshan S. Collagenolytic activity in keratoconus. Ann Ophthalmol. 1982;14:751–4. - PubMed
    1. Kenney MC, Chwa M, Escobar M, Brown D. Altered gelatinolytic activity by keratoconus corneal cells. Biochem Biophys Res Commun. 1989;161:353–7. - PubMed
    1. Fini ME, Yue BY, Sugar J. Collagenolytic/gelatinolytic metalloproteinases in normal and keratoconus corneas. Curr Eye Res. 1992;11:849–62. - PubMed

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