Stage-Specific miRs in Chondrocyte Maturation: Differentiation-Dependent and Hypertrophy-Related miR Clusters and the miR-181 Family

Abstract

Human mesenchymal stromal cells (hMSC) differentiating toward the chondrogenic lineage recapitulate successive phases of embryonic chondrocyte maturation developing from progenitor cells to hypertrophic chondrocytes. Osteoarthritic cartilage is characterized by an alteration in chondrocyte metabolism and upregulation of hypertrophic differentiation markers. A number of studies point toward a functional role for microRNAs (miRs) in controlling chondrocyte differentiation and development of osteoarthritis (OA). However, information on miRs that may regulate a specific phase of chondrocyte maturation, especially hypertrophy, is lacking. We here aimed to unravel miR profiles modulated during chondrogenesis of hMSC to obtain new differentiation markers and potential new targets relevant for differentiation outcome and OA development. hMSC were subjected to transforming growth factor-β (TGF-β)-driven chondrogenesis and miR profiles were determined by microarray analysis at distinct developmental time points. Expression of selected miRs was compared to cultures lacking chondrogenesis and to redifferentiated nonhypertrophic articular chondrocytes. Among 1349 probed miRs, 553 were expressed and 169 (31%) were significantly regulated during chondrogenesis. Hierarchical clustering identified specific miR expression patterns representative for MSC, prechondrocytes, chondroblasts, chondrocytes, and hypertrophic chondrocytes, respectively. Regulation of miR-181 family members allowed discrimination of successive differentiation stages. Levels of several miRs, including miR-23b, miR-140, miR-181, and miR-210 positively correlated with successful chondrocyte formation. Hypertrophic MSC-derived chondrocytes and nonhypertrophic articular chondrocytes showed differential expression of miR-181a, miR-210, and miR-31, but not miR-148a implicated in COL10A1-regulation. We conclude that the here identified stage-dependent miR clusters may have imperative functions during chondrocyte differentiation providing novel diagnostic tools and targets of potential relevance for OA development.

Targeting anti‐chondrogenic factors for the stimulation of chondrogenesis: A new paradigm in cartilage repair

“…A recent miRNA expression profile study showed that 169 miRNAs were modulated during hMSC chondrogenesis . Notably, 93 of these miRNAs were significantly downregulated, with the expression of 62 miRNAs being completely lost in the transition from MSC to pre‐chondrocyte stage.…”

“…A recent miRNA expression profile study showed that 169 miRNAs were modulated during hMSC chondrogenesis. 70 Notably, 93 of these miRNAs were significantly downregulated, with the expression of 62 miRNAs being completely lost in the transition from MSC to pre-chondrocyte stage. Similar evidence was provided by other studies, 71 suggesting that several microRNAs might exert anti-chondrogenic functions and that suppression of these regulators may be required for chondrogenesis to take place.…”

Differential expression of TGF-β superfamily members and role of Smad1/5/9-signalling in chondral versus endochondral chondrocyte differentiation

“…However, DM may also affect chondrogenic power due to interference with additional receptors like the type II receptor ActRIIA40 and may even affect TGFBR2 like the structurally similar LDN-19318941. Delayed addition of DM from day 14 also strongly reduced collagen type II deposition and appeared to delay chondrogenesis in a way that hypertrophic and osteogenic markers were still significantly lower and no collagen type X protein was yet detected at day 42 by Western blotting42. Conclusively this emphasized that an important pro-chondrogenic stimulus was coming from ALK1,2,3,6 downstream signalling at early and late stages of chondrogenesis and its inhibition did not allow an uncoupling of SOX9-driven cartilage matrix production from RUNX2-driven hypertrophy to reach a phenotype similar to AC.…”

Onset and Progression of Human Osteoarthritis—Can Growth Factors, Inflammatory Cytokines, or Differential miRNA Expression Concomitantly Induce Proliferation, ECM Degradation, and Inflammation in Articular Cartilage?

“…Moreover, activity of MMP-2 and MMP-9 is enhanced by miR-181 mimic [212]. In addition, elevated miR-181a expression is associated with successful chondrogenesis of human MSPCs [213]. However, there are also studies showing a decreased expression of miR-181 family members, including miR-181a, in OA AC cell monolayer cultures, compared to healthy AC cells from younger donors [191,214].…”