Purchase this article with an account.
R. K. Kutty, C. N. Nagineni, W. Samuel, C. Vijayasarathy, J. J. Hooks, T. M. Redmond; Inflammatory Cytokines Regulate the Expression of MicroRNA-155 (miR-155) in Human Retinal Pigment Epithelial Cells. Invest. Ophthalmol. Vis. Sci. 2009;50(13):478.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Inflammatory processes are known to be involved in the development of age-related macular degeneration (AMD). Human retinal pigment epithelial (HRPE) cells in culture respond to inflammatory cytokines by increasing the expression of a number of genes including many chemokines and cytokines. The aim of the present study is to investigate the role in this process of miRNAs, a class of non-coding small RNA known to control gene expression by regulating the stability and/or the translation of target mRNA.
Confluent cultures of HRPE cells established from donor eyes were treated with the cytokines in serum free medium for 16 hours. Total RNA fraction containing miRNA was isolated using mirVana miRNA isolation kit (Applied Biosystems), and the miRNA expression profile was analyzed by microarray hybridization (LC Sciences). Gene expression and miR-155 expression were analyzed by real-time PCR using TaqMan reagents (Applied Biosystems).
Microarray analysis identified miR-155 as the predominant miRNA that is induced by cytokine mix (IFN-γ, TNF- and IL-1β) in HRPE cells. Real-time PCR analysis showed that the miR-155 expression increased ~10-fold under this condition. The increase in the expression was noticed as early as 2 hours after treatment, and the time-dependent increase continued for up to 24 hours. The observed alteration in miR-155 expression by the cytokine mix was associated with marked increases in the expression of CCL2, CCL5, CXCL9, CXCL10 and IL-6 transcripts as well as corresponding proteins. Cultures treated individually with IFN-γ, TNF- or IL-1β showed noticeable but small increases in miR-155 expression, but combination of any two exaggerated the effect. Highest induction was observed when all three cytokines were present, and was effectively blocked when the JAK/STAT signaling pathway was inhibited.
Our results clearly show that the inflammatory cytokines can modulate miR-155 expression in human retinal pigment epithelial cells. Thus, miR-155, an miRNA implicated in immunity, infection and oncogenesis, could play an important role in inflammatory processes leading to AMD or other retinal degenerative diseases.
This PDF is available to Subscribers Only