Mohamad Eftekhary - Department of Biotechnology, School of Advanced Technologies in Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
Samira Mohammadi‐Yeganeh - Cellular and Molecular Biology Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
Seyed Mahmoud Hashemi - Department of Immunology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
Hossein Ghanbarian - Department of Biotechnology, School of Advanced Technologies in Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran

Introduction The transcription factor SOX9, a key regulatory factor in chondrogenesis, induces expression of collagen type II and Aggrecan genes during differentiation of Mesenchymal stem cell (MSC) into chondrocyte. Recent studies have shown that long non-coding RNAs, such as natural antisense transcript (NAT) can play regulatory roles in gene expression.ObjectiveWe identified the presence of NAT in the SOX9 locus and its transcriptional level was detected at different time points during MSC chondrocyte differentiation.MethodsHuman MSCs were isolated from adipose tissue by enzymatic digestion, Collagenase TYPE 1. AD-MSCs were then characterized by Flow cytometry and analyzed for their ability to differentiate into osteoblasts and adipocytes. To detect NAT SOX9, strand specific reverse transcription polymerase chain reaction (RT-PCR) was performed. The expression levels of SOX9sense and antisense (AS) transcripts were assessed during chondrogenesis in different time points by real time-PCR assay.ResultsWe identified, for the first time, the presence of NAT in the SOX9 locus in human MSCs. While SOX9 mRNA level was up-regulated during chondrogenic differentiation, the expression level of SOX9-AS decreased, suggesting a possible inhibitory role of antisense transcripts on SOX9 expressionConclusionOur present study reveals that a natural antisense transcript is expressed in SOX9 locus, suggesting a regulatory role on SOX9 during chondrogenesis

MSC, SOX9, Chondrocyte, Long non-coding RNA, Antisense transcript