Biomarkers and Proteomics in Corneal Cell Biology

Abstract

AbstractPurpose Developing a basis for personalized medicine requires instrumentation that has a high throughput and appropriate senstivity. To discover proteomic biomarkers of ocular surface diseases using quantitative mass spectrometry for discovery of molecular representatives within the tear film that can be used for clinical application and pharmacological development. Additionally, proteomics carried out by mass spectrometry provides a ready tool for use with quantitative biomarkers.Methods Tear samples can be collected by several means, our lab usually uses type I Schirmer’s test from patients and has been used successfully with patients with dry eye, pterygium or on anti‐glaucoma medications as well as age‐matched healthy unmedicated controls. Tear proteins are analyzed using iTRAQ (Isobaric tags for relative and absolute quantification) based quantitative proteomics or SELDI mass spectrometry. ELISA is used for confirmation of proteomic findings.Results In dry eye patients, over 200 tear proteins have been identified. Potential biomarkers include up‐regulated proteins, alpha‐enolase, alpha‐1‐acid glycoprotein 1, S100 A8, S100 A9, S100 A4 and S100. In chronic glaucoma patients, 128 tear proteins were identified with 99% confidence. We found 5 proteins whose iTRAQ ratios showed significant changes (p < 0.05) when comparing non‐medicated control group and medicated group. Levels of 4 tear proteins (S100 A8, S100 A9, mammaglobin B and 14‐3‐3 z/d protein) were elevated.Conclusion Proteomic biomarkers provide new insights into the disease process as with the inflammatory S100 proteins found here and they are measurable end points for drug development, diagnosis and response to treatment. A biomarker panel for dry eye has been developed for patient use.