Androgen suppresses hyperosmolarity-induced inflammatory mediators in human corneal epithelial cells

Abstract

Purpose: To investigative the effects of sex steroids on hyperosmolar stress-induced proinflammatory cytokine expression of tumor necrosis factor-alpha (TNF-alpha), interleukin (IL)-8, and IL-6, and on the mitogen-activated protein kinase pathway in immortalized human corneal epithelial cells (hCECs). Methods: Immortalized hCECs were cultured with keratinocyte-free medium until reaching 80% confluency with either 10(-8)M dihidrotestosteron (DHT) or 10(-8)M 17-beta-estradiol, and then, the medium was changed to hyperosmolar for various time points. After hyperosmolar treatment, a real-time polymerase chain reaction was performed to show the TNF-alpha, IL-8, and IL-6 gene expression levels in hCECs. In addition, the treated cells were lysed, and Western blot analysis was applied for phosphorylated and nonphosphorylated forms of extracellular signal-regulated kinase 1/2 (ERK1/2), p38 kinase, and c-Jun N-terminal kinase 1/2 (JNK1/2). hCECs viability was measured with Annexin V/propidium iodide. Results: Pretreatment with 10(-8)M DHT or 17-beta-estradiol inhibited the high osmolarity-induced expression of TNF-alpha, IL-8, and IL-6. The upregulation of p-ERK, p-JNK, and p-p38 with high osmolarity was inhibited partially by DHT, but 17-beta-estradiol pretreatment only affected p-p38 for a short time interval. In addition, DHT increased cell viability of hCECs under hyperosmolar conditions. Conclusions: Our results demonstrated that DHT and 17-beta-estradiol decreased the proinflammatory cytokine gene expression levels which were stimulated by high osmolarity in immortalized hCECs. The mitogen-activated protein kinase signaling pathway is partially involved in the regulatory effects of DHT on hCECs. These findings may contribute to the etiologic role and therapeutic implications of sex steroids in certain ocular surface diseases.