MicroRNA-200a Regulates the Development of Mandibular Condylar Cartilage

Abstract

Mandibular condylar cartilage (MCC) is classified as secondary cartilage, the histologic structure of which is unique from that of primary cartilage. MicroRNA (miRNA) is a small noncoding RNA that binds to the messenger RNA (mRNA) target to repress its translation and plays an important role in cell differentiation, proliferation, and death. Microarray analysis revealed that miR-200a was characteristically expressed during embryonic development. We hypothesized that miR-200a may be involved in regulating the formation of cartilage during MCC growth. We investigated the function of miR-200a by transfecting an inhibitor or mimic into MCC organ and cell cultures. A histologic examination revealed the localized inhibitory effects of the miR-200a mimic and widespread enhancing effects of the inhibitor on chondrocytic differentiation in the MCC organ culture system. An immunohistochemical examination and gene expression analysis demonstrated that the miR-200a inhibitor enhanced chondrogenesis, while the mimic had the opposite effect by enhancing cell proliferation. Quantitative reverse transcription polymerase chain reaction analysis revealed that miR-200a downregulated the gene expression of chondrocyte markers. Moreover, transfection of the miR-200a mimic into ATDC5 cells repressed the formation of the cartilaginous matrix. These results indicate that miR-200a contributed to chondrogenesis in developing MCC by controlling proliferation and differentiation in MCC cells.

The Role of MicroRNAs and Their Targets in Osteoarthritis

“…These miRNAs include miR-16-5p and miR-337, both of which target Smad3 [146] and TGFβR2 [147], respectively. A number of other miRNAs may target SOX9 and COL2A1 in chondrocytes including miR-101 [148], miR-675 [149], and miR-200a [150]. Interestingly, inhibition of these miRNAs may enhance chondrogenesis and have a protective function in OA conditions.…”

MicroRNA‐3064‐3p regulates the differentiation of cementoblasts through targeting DKK1

“…MicroRNAs (miRNAs) are endogenous, short (~22 nucleotide), noncoding, single‐stranded RNAs that can regulate translational inhibition or mRNA degradation by binding to the 3′ untranslated regions (3′‐UTRs) of some specific mRNAs . Studies have shown that miRNAs participate in a range of pathological and physiological processes, including cell proliferation, differentiation, apoptosis, organ development, and tumor oncogenesis . In particular, numerous studies have published that miRNAs play critical roles in osteogenic differentiation .…”

Emerging potential of gene silencing approaches targeting anti-chondrogenic factors for cell-based cartilage repair

“…Umeda et al identified miR200a as a major regulator of the formation of cartilage during mandibular condylar cartilage (MCC) development. Transfection of antimiR-200a in MCC cells or organ culture positively influenced chondrogenesis, inducing the expression of Sox9 and collagen type II [24].…”

“…Nevertheless, increasing evidence strongly suggests that the silencing of key anti-chondrogenic regulators may be effectively employed to enhance or even induce chondrogenesis, stimulate the production of cartilage matrix, and improve or stabilize the chondrocytic phenotype [21][22][23][24].…”

“…Increased expression of collagen II, IX, XI, aggrecan, and COMP [96] miR-34a Increased synthesis of cartilage ECM (collagen II, GAGs) by limb bud mesenchymal cells. Protection of human chondrocytes from inflammatory stimuli (IL-1b) [98,100] miR-142 Increased cell viability, proliferation, migration and precartilage condensation of mesenchymal cells [99] miR-375 Increased proliferation, migration and precartilage condensation of mesenchymal cells [97] miR-99a Promotion of early chondrogenesis of rat MSCs with increased production of cartilage ECM (collagen II, aggrecan, GAGs) [101] miR-193b Increased expression of SOX9, collagen II and aggrecan in human chondrocytes [93] miR-200a Enhanced chondrogenesis in MCC cells and organ cultures, with increased levels of SOX9 and collagen II [24] miR-221…”