Doxycycline's and ocular angiogenesis

Identification and Interaction Analysis of Significant Genes and MicroRNAs in Pterygium

PURPOSE

MiRNAs have been widely analyzed in the occurrence and development of many diseases, including pterygium. This study aimed to identify the key genes and miRNAs in pterygium and to explore the underlying molecular mechanisms.

METHODS

MiRNA expression was initially extracted and pooled by published literature. Microarray data about differentially expressed genes was downloaded from Gene Expression Omnibus (GEO) database and analyzed with the R programming language. Functional and pathway enrichment analyses were performed using the database for Annotation, Visualization and Integrated Discovery (DAVID). The protein-protein interaction network was constructed with the STRING database. The associations between chemicals, differentially expressed miRNAs, and differentially expressed genes were predicted using the online resource. All the networks were constructed using Cytoscape.

RESULTS

We found that 35 miRNAs and 301 genes were significantly differentially expressed. Functional enrichment analysis showed that upregulated genes were significantly enriched in extracellular matrix (ECM) organization, while downregulated genes were mainly involved in cell death and apoptotic process. Finally, we concluded the chemical-gene affected network, miRNA-mRNA interacted networks, and significant pathway network.

CONCLUSION

We identified lists of differentially expressed miRNAs and genes and their possible interaction in pterygium. The networks indicated that ECM breakdown and EMT might be two major pathophysiological mechanisms and showed the potential significance of PI3K-Akt signalling pathway. MiR-29b-3p and collagen family (COL4A1 and COL3A1) might be new treatment target in pterygium.

Comparison of gene expression profiles in primary and immortalized human pterygium fibroblast cells

PURPOSE

Pterygium is a fibrovascular growth on the ocular surface with corneal tissue destruction, matrix degradation and varying extents of chronic inflammation. To facilitate investigation of pterygium etiology, we immortalized pterygium fibroblast cells and profiled their global transcript levels compared to primary cultured cells.

METHODS

Fibroblast cells were cultured from surgically excised pterygium tissue using the explant method and propagated to passage number 2-4. We hypothesized that intervention with 3 critical molecular intermediates may be necessary to propage these cells. Primary fibroblast cells were immortalized sequentially by a retroviral construct containing the human telomerase reverse transcriptase gene and another retroviral expression vector expressing p53/p16 shRNAs. Primary and immortalized fibroblast cells were evaluated for differences in global gene transcript levels using an Agilent Genechip microarray.

RESULTS

Light microscopic morphology of immortalized cells was similar to primary pterygium fibroblast at passage 2-4. Telomerase reverse transcriptase was expressed, and p53 and p16 levels were reduced in immortalized pterygium fibroblast cells. There were 3308 significantly dysregulated genes showing at least 2 fold changes in transcript levels between immortalized and primary cultured cells (2005 genes were up-regulated and 1303 genes were down-regulated). Overall, 13.58% (95% CI: 13.08-14.10) of transcripts in immortalized cells were differentially expressed by at least 2 folds compared to primary cells.

CONCLUSION

Pterygium primary fibroblast cells were successfully immortalized to at least passage 11. Although a variety of genes are differentially expressed between immortalized and primary cells, only genes related to cell cycle are significantly changed, suggesting that the immortalized cells may be used as an in vitro model for pterygium pathology.