Abstract
Purpose: :
To examine the tear and corneal protein profile of fungal keratitis patients, which may have a bearing on pathogenesis and disease progression both in the early and late stage of the infection.
Methods: :
Tear samples were collected from culture positive fungal keratitis patients and healthy humans. Fungal infected corneas were obtained during their removal at the time of transplantation, and normal corneas were obtained from Rotary Aravind International Eye Bank. Tear and corneal proteins were separated on 2D DIGE and 2D respectively. Differentially expressed protein spots were identified by MALDI TOF or Nano LC-MS/MS. DeCyder software was used for spot comparison and quantitation
Results: :
Complex patterns of tear and corneal proteins were detected. Among 62 tear proteins identified, 2D-DIGE analysis showed down regulation of 12 proteins including lipocalin precursors, Lysozyme-C precursor,Cystatin precursors,Lacritin Precursor, Mammaglobin-B precursor, Lactoferrin, Prolactin inducible protein and up regulation of 13 proteins including Serum albumin, Haptoglobin, Apolipoprotein E, Actin in the infected tear samples. Among 30 corneal proteins identified, Transforming growth factor precursor,Glutathione S-transferase, Peroxiredoxin 2, Chloride intracellular channel proteins were down regulated and Transthyretin precursor, Ferritin light chain were up regulated in the Fusarium, A.flavus, A.fumigatus infected corneas when compared to normal corneas with respect to 3 biological replicates in each group. Comparing Tear and Cornea 2D profile,16 proteins are identical,among them 14 have been identified.
Conclusions: :
The down regulated tear and corneal proteins are known to be involved in local immune function and oxidative stress related gene expression respectively. The presence of identical proteins between tear and cornea gives possible clues about the migration of the proteins. Thus this is the first study to reveal the significance of tear and corneal proteomic responses in fungal keratitis with respect to early and late stage of infection, which can give further insights for better treatment.
Keywords: keratitis • cornea: tears/tear film/dry eye • proteomics