Upregulation of S100A9 in orbital tissues of patients with thyroid eye disease.

PURPOSE: To identify the differentially expressed genes in the orbital tissues of patients with thyroid eye disease (TED).

METHODS

The microarray datasets on the orbital tissues of TED patients were collected from the Gene Expression Omnibus DataSets. Upon filtering, the differentially expressed genes (DEGs) of the selected dataset were determined and evaluated by gene ontology analysis. The expressions of genes related to the TED pathophysiological changes were validated by SYBR Green polymerase chain reaction (PCR) and immunofluorescence analyses on separate TED and control orbital tissue specimens.

RESULTS

Analysis on the orbital tissue samples of TED patients in the GSE58331 dataset identified 74 DEGs. Gene ontology analysis revealed that the DEGs are involved in the endocytosis, innate immunity, and extracellular matrix. Out of the 10 selected genes, only S100A9 showed significant upregulation in the orbital tissues of TED patients as compared to that of the control subjects (P = 0.006) in the SYBR Green PCR validation experiment. Immunofluorescence analysis confirmed significantly elevated expression of S100A9 in the orbital tissues of TED patients (P = 0.008). The receiver-operating characteristic curve (ROC) analysis demonstrated that the area under the ROC curve of S100A9 was 0.79 for the discrimination of the TED patients from the control subjects.

CONCLUSION

This study revealed the upregulation of S100A9 in the orbital tissues of TED patients, suggesting that it could be involved in the development of TED.