Differential Regulation of circRNA, miRNA, and piRNA during Early Osteogenic and Chondrogenic Differentiation of Human Mesenchymal Stromal Cells

Abstract

The goal of the present study is to identify the differential expression of circular RNA (circRNA), miRNA, and piwi-interacting RNA (piRNA) after lineage commitment towards osteoand chondrogenesis of human bone marrow mesenchymal stromal cells (hMSCs). The cells were maintained for 7 days in either osteogenic or chondrogenic medium. RNA sequencing was performed to assess the expression of miRNA and piRNA, while RNA hybridization arrays were used to identify which circRNA were differentially expressed. qPCR validation of a selection of targets for both osteogenic and chondrogenic differentiation was carried out. The differential expression of several circRNA, miRNA, and piRNA was identified and validated. The expression of total and circular isoforms of FKBP5 was upregulated both in osteo-and chondrogenesis and it was influenced by the presence of dexamethasone. ZEB1, FADS2, and SMYD3 were also identified as regulated in differentiation and/or by dexamethasone. In conclusion, we have identified a set of different non-coding RNAs that are differentially regulated in early osteogenic and chondrogenic differentiation, paving the way for further investigation to understand how dexamethasone controls the expression of those genes and what their function is in MSC differentiation.

Adipogenesis, Osteogenesis, and Chondrogenesis of Human Mesenchymal Stem/Stromal Cells: A Comparative Transcriptome Approach

“…Recently several circRNAs, miRNAs and piRNA were differentially expressed after 7 days of chondrogenic and osteogenic induction ( Della Bella et al, 2020 ). This analysis identified 130 up and 97 downregulated circRNAs in chondrogenesis, of which 15 were also identified in osteogenesis.…”

“…Investigating if the expression of these genes were influenced by dexamethasone, a component of both induction media ( Table 1 ), the cells were exposed only to the compound in monolayer or pellet culture. The results indicated that while the expression of FKBP5 was affected by the presence of dexamethasone, FASD2 gene showed no alteration in its levels ( Della Bella et al, 2020 ). FASD2 and FKBP5 were previously identified in chondrogenic induction.…”

“…Regarding miRNAs, more than 200 were identified as differentially expressed (102 up and 108 downregulated) in chondrogenic differentiation ( Della Bella et al, 2020 ). Its mRNA targets had relation to PI3K-AKT signaling pathway, NK-kappa B signaling pathway and others.…”

“…Furthermore, the identification of miRNAs allowed to relate them with the circRNA expressed in chondrogenesis, once they can act as miRNAs sponges. For example, some of circRNAs with binding sites for hsa-miR-665 were upregulated (hsa_circRNA_081069, hsa_circRNA_100833, hsa_circRNA_002161), while the miRNA was downregulated ( Della Bella et al, 2020 ). An interesting observation is that while in osteogenesis only 54 piRNAs were differentially expressed, in chondrogenesis it was identified 131 piRNAs, the most part upregulated (73).…”

“…An interesting observation is that while in osteogenesis only 54 piRNAs were differentially expressed, in chondrogenesis it was identified 131 piRNAs, the most part upregulated (73). But future studies need to be performed to understand the role of this class of RNA in differentiation process ( Della Bella et al, 2020 ).…”