Detection of differentially expressed genes in healing mouse corneas, using cDNA microarrays

PURPOSE. To identify differentially expressed genes in healing mouse corneas by using cDNA microarrays. METHODS. Transepithelial excimer laser ablations were performed on mouse corneas, and the wounds were allowed to heal partially in vivo for 18 to 22 hours. Total RNA was isolated from both normal and healing corneas and was used for synthesis of cDNA probes. 33 P-labeled exponential cDNA probes were hybridized to mouse cDNA nylon arrays. RESULTS. Of the 1176 genes on the nylon arrays, the expression of 37 was upregulated and that of 27 was downregulated more than fivefold in the healing corneas compared with the normal, uninjured corneas. Interleukin (IL)-1beta, laminin-5, and thrombospondin-1, which have been shown to be upregulated in healing corneas, were all found to be induced in the corneas in response to excimer laser treatment. Many genes were identified for the first time to be differentially regulated during corneal wound healing. Among the upregulated genes were intercellular adhesion molecule (ICAM)-1, macrophage inflammatory proteins, suppressors of cytokine signaling proteins (SOCS), IL-10 receptor, and galectin-7. Among the downregulated genes were connexin-31, a gap junction protein; ZO1 and occludin, tight junction proteins; and Smad2, a key component in the TGFbeta signaling pathway. Microarray data were validated on a limited number of genes by semiquantitative RT-PCR and Western blot analyses. CONCLUSIONS. Gene array technology was used to identify for the first time many genes that are differentially regulated during corneal wound healing. These differentially expressed genes have not previously been investigated in the context of wound healing and represent novel factors for further study of the mechanism of wound healing.