Arthritis & Rheumatism, Volume 62,
November 2010 Abstract Supplement

Abstracts of the American College of
Rheumatology/Association of Rheumatology Health Professionals
Annual Scientific Meeting
Atlanta, Georgia November 6-11, 2010.


Down-Regulated MicroRNA-152 Induces Aberrant DNA Methylation in Scleroderma Endothelial Cells by Targeting DNA Methyltransferase 1.

Wang,  Yongqing, R. Kahaly,  Omar, Kahaleh,  Bashar

Objectives:

The underlying mechanism of epigenetic imprinting in SSc microvascular endothelial cells (MVEC) remains unknown. MicroRNAs (miRNAs), which are noncoding RNAs that regulate gene expression, are involved in diverse biological functions. In this study, we investigated whether miRNAs are aberrantly expressed in SSc-MVEC and if they are involved in the regulation of epigenetic imprinting in SSc.

Methods:

The expression levels of the 376 most abundantly expressed miRNAs in the human genome were determined in SSc and control MVEC (derived from 6 SSc and matched control subjects) by RT2 microRNA PCR array. Control and SSc MVEC were transfected with 1.0ug of miRNA isolated from SSc or control MVEC. After 48 hours, cells were harvested and the expression levels of endothelial nitric oxide synthase (NOS3) and DNA methyltransferases1 (DNMT1) were measured by real-time PCR. The expression levels of miR-152 were determined by quantitative PCR. Finally, miRNA-152 was forced expressed or inhibited in SSc and control MVEC.

Results:

Significant differences in the expression levels of miRNAs were noted in SSc-MVEC. To understand the role of altered miRNAs expression in SSc, control-MVEC were transfected with SSc- derived miRNAs which resulted in significant increase expression of DNMT1 (2.5± 0.3 folds, mean ±SD) and reduced NOS3 expression level (25±9%, percent of control). While, the transfection of SSc-MVEC with control miRNAs resulted in decreased expression of DNMT1 and increased expression of NOS3. Since DNMT1 is one of the predicted direct targets of miR-152, we investigated the expression levels of miR-152 in SSc and control MVEC. Levels were frequently down-regulated in SSc-MVEC and were inversely correlated to DNMT1 expression levels. Forced expression of miR-152 in SSc-MVEC led to a reduction in DNMT1 expression at both the mRNA and protein levels in comparison with the negative control, while inhibition of miR-152 expression in control- MVEC enhanced DNMT1 expression levels in association with reduced NOS3 expression level.

Conclusions:

· SSc-miRNAs transfection into control-MVEC can induce SSc-MVEC phenotype.

· miR-152 expression is down regulated in SSc-MVEC and inversely correlates with DNMT1 expression level.

· The forced expression of miR-152 corrected SSc-MVEC phenotype and its inhibition induced SSc phenotype in control MVEC.

· miR- 152 may play a causal role in DNA methylation changes in SSc-MVEC.

To cite this abstract, please use the following information:
Wang, Yongqing, R. Kahaly, Omar, Kahaleh, Bashar; Down-Regulated MicroRNA-152 Induces Aberrant DNA Methylation in Scleroderma Endothelial Cells by Targeting DNA Methyltransferase 1. [abstract]. Arthritis Rheum 2010;62 Suppl 10 :1352
DOI: 10.1002/art.29118

Abstract Supplement

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