MicroRNA‐138 Inhibits Osteogenic Differentiation and Mineralization of Human Dedifferentiated Chondrocytes by Regulating RhoC and the Actin Cytoskeleton

Abstract

MicroRNAs (miRNAs) are known to play critical roles in many cellular processes including those regulating skeletal development and homeostasis. A previous study from our group identified differentially expressed miRNAs in the developing human growth plate. Among those more highly expressed in hypertrophic chondrocytes compared to progenitor chondrocytes was miR‐138, therefore suggesting a possible role for this miRNA in regulating chondrogenesis and/or endochondral ossification. The goal of this study was to determine the function of miR‐ 138 in regulating osteogenesis by using human osteoarthritic dedifferentiated chondrocytes (DDCs) as source of inducible cells. We show that over‐expression of miR‐138 inhibited osteogenic differentiation of DDCs in vitro. Moreover, cell shape was altered and cell proliferation and possibly migration was also suppressed by miR‐138. Given alterations in cell shape, closer analysis revealed that F‐actin polymerization was also inhibited by miR‐138. Computational approaches showed that the small GTPase, RhoC, is a potential miR‐138 target gene. We pursued RhoC further given its function in regulating cell proliferation and migration in cancer cells. Indeed, miR‐138 over‐expression in DDCs resulted in decreased RhoC protein levels. A series of rescue experiments showed that RhoC over‐expression could attenuate the inhibitory actions of miR‐138 on DDC proliferation, F‐actin polymerization and osteogenic differentiation. Bone formation was also found to be enhanced within human demineralized bone scaffolds seeded with DDCs expressing both miR‐138 and RhoC. In conclusion, we have discovered a new mechanism in DDCs whereby miR‐138 functions to suppress RhoC which subsequently inhibits proliferation, F‐actin polymerization and osteogenic differentiation. To date, there are no published reports on the importance of RhoC in regulating osteogenesis. This opens up new avenues of research involving miR‐138 and RhoC pathways to better understand mechanisms regulating bone formation in addition to the potential use of DDCs as a cell source for bone tissue engineering. © 2018 The Authors. JBMR Plus is published by Wiley Periodicals, Inc. on behalf of the American Society for Bone and Mineral Research.

MicroRNA-181a/b-1 over-expression enhances osteogenesis by modulating PTEN/PI3K/AKT signaling and mitochondrial metabolism

“…Also, stem-like cells with tri-lineage potential (osteogenic, adipogenic, chondrogenic) have been shown to exist in both human healthy and OA articular cartilage (48)(49)(50). We recently published data on the inhibitory effects of miR-138 on osteogenic differentiation of DDCs (46). The same miR-138-mediated osteo-suppressive effect has also been reported using MSCs (51).…”

“…We consistently achieve efficient chondrogenic and osteogenic differentiation of DDCs and MSCs, yet always find adipogenic differentiation to be more robust in MSC cultures. While DDCs from healthy articular cartilage have also been reported to have osteogenic potential (45), we recently published data showing successful osteogenic differentiation of DDCs harvested from human OA cartilage (46). In this work, increased expression of osteoblast-related proteins, RUNX2 and osteocalcin, was found in addition to production of a mineralized extracellular matrix (ECM) during osteogenic induction of DDCs.…”

“…In this work, increased expression of osteoblast-related proteins, RUNX2 and osteocalcin, was found in addition to production of a mineralized extracellular matrix (ECM) during osteogenic induction of DDCs. We also found that transduction of DDCs with a lentivirus expressing a non-silencing (NS) control RNA (LV-NS) did not affect the ability of these cells to differentiate and form a calcified ECM (46). Therefore, in these studies, LV-181a/b-1transduced cultures were always compared to control LV-NS transduced cells.…”

Sdccag3 Promotes Implant Osseointegration during Experimental Hyperlipidemia

“…Long noncoding RNAs (lncRNAs), which are important ncRNAs more than 200 nucleotides (nt) in length, have been shown to modulate posttranscriptional events during gene expression (Yoon et al 2012; Kopp and Mendell 2018; Tang et al 2019). MicroRNAs (miRNAs), which constitute another major type of ncRNA, have been shown to regulate osteoblast differentiation (Zhou et al 2016; Huang, Wang, Li, Huang, et al 2018; Zheng et al 2019) and implant osseointegration (Liu et al 2018).…”

LncRNA LINC01503 aggravates the progression of cervical cancer through sponging miR-342-3p to mediate FXYD3 expression

“…MicroRNAs (miRNAs) are small RNAs that have no protein-coding capacity and play a key role in cellular activities, such as cell proliferation, migration, invasion and apoptosis [22][23][24]. Accumulating evidence has clarified that miRNA functions as an oncogene or a tumor-suppressor to modulate mRNA expression in a variety of cancers [25][26][27]. For instance, miRNA-518 targets MDM2 to inhibit cell growth and induce cell apoptosis in gastric cancer [28].…”