Abnormal regulation of extracellular matrix and adhesion molecules in corneas of patients with keratoconus

Abstract

Aim: To identify changes in the expression of genes coding for extracellular matrix (ECM) proteins in patients with non-inflammatory corneal disorder keratoconus (KC), patients with corneal scarring, and normal controls.

Materials and methods: Total RNA extracted from corneal tissue of 13 KC patients, 2 patients with corneal scaring and 4 normal controls was analyzed using Human Extracellular Matrix & Adhesion Molecules Profiler PCR Array. Statistically significant changes in gene expression were identified using the Data Analysis software.

Results: Comparison of KC and control corneas with thresholds of 1.5 or greater fold change and a p-value of 0.05 or lower, revealed 21 differentially expressed genes, 16 genes were downregulated and 5 were upregulated. Among transcripts downregulated in KC patients we identified THBS1, ADAMTS1, SPP1, several collagens and integrins. We found TGFBI (BIGH3) gene was the most significantly upregulated transcript.

Conclusion: Development of keratoconus results in deregulation of gene expression of extracellular matrix and adhesion molecules.

Clinical significance: Downregulation of collagens and upregulation of TGFBI repeatedly identified in KC patients may be used as clinical markers of the disease.

Keywords: Laboratory research; adhesion; collagens; expression; extracellular matrix; keratoconus.

Figure 1

Unsupervised clustering analysis of expression levels of genes assessed by the Human Extracellular Matrix & Adhesion Molecules RT² Profiler PCR Array in corneal RNA samples of KC patients (K) and normal controls (C). Samples are identified by their sample IDs as described in Table 1 and throughout the text.

Figure 2

Expression levels of collagen genes in KC patients (red) and controls (blue). Fold difference is graphed on the Y axis. * denotes statistically significant results.