miRNA-140 inhibits C3H10T1/2 mesenchymal stem cell proliferation by targeting CXCL12 during transforming growth factor-β3-induced chondrogenic differentiation

A Residual N-Terminal Peptide Enhances Signaling of Depalmitoylated Hedgehog to the Patched Receptor

During their biosynthesis, Sonic hedgehog (Shh) morphogens are covalently modified by cholesterol at the C-terminus and palmitate at the N-terminus. Although both lipids initially anchor Shh to the plasma membrane of producing cells, it later translocates to the extracellular compartment to direct developmental fates in cells expressing the Patched (Ptch) receptor. Possible release mechanisms for dually lipidated Hh/Shh into the extracellular compartment are currently under intense debate. In this paper, we describe the serum-dependent conversion of the dually lipidated cellular precursor into a soluble cholesteroylated variant (ShhC) during its release. Although ShhC is formed in a Dispatched- and Scube2-dependent manner, suggesting the physiological relevance of the protein, the depalmitoylation of ShhC during release is inconsistent with the previously postulated function of N-palmitate in Ptch receptor binding and signaling. Therefore, we analyzed the potency of ShhC to induce Ptch-controlled target cell transcription and differentiation in Hh-sensitive reporter cells and in the Drosophila eye. In both experimental systems, we found that ShhC was highly bioactive despite the absence of the N-palmitate. We also found that the artificial removal of N-terminal peptides longer than eight amino acids inactivated the depalmitoylated soluble proteins in vitro and in the developing Drosophila eye. These results demonstrate that N-depalmitoylated ShhC requires an N-peptide of a defined minimum length for its signaling function to Ptch.

Regulatory of miRNAs in tri-lineage differentiation of C3H10T1/2

MicroRNAs (miRNAs) are non-coding single-stranded RNA molecules encoded by endogenous genes, which play a vital role in cell generation, metabolism, apoptosis and stem cell differentiation. C3H10T1/2, a mesenchymal cell extracted from mouse embryos, is capable of osteogenic differentiation, adipogenic differentiation and chondrogenic differentiation. Extensive studies have shown that not only miRNAs can directly trigger targeted genes to regulate the tri-lineage differentiation of C3H10T1/2, but it also can indirectly regulate the differentiation by triggering different signaling pathways or various downstream molecules. This paper aims to clarify the regulatory roles of different miRNAs on C3H10T1/2 differentiation, and discussing their balance effect among osteogenic differentiation, adipogenic differentiation and chondrogenic differentiation of C3H10T1/2. We also review the biogenesis of miRNAs, Wnt signaling pathways, MAPK signaling pathways and BMP signaling pathways and provide some specific examples of how these signaling pathways act on C3H10T1/2 tri-lineage differentiation. On this basis, we hope that a deeper understanding of the differentiation and regulation mechanism of miRNAs in C3H10T1/2 can provide a promising therapeutic method for the clinical treatment of bone defects, osteoporosis, osteoarthritis and other diseases.

miR-199b-5p promoted chondrogenic differentiation of C3H10T1/2 cells by regulating JAG1

Mesenchymal stem cells (MSCs) are considered a promising candidate for use in cell-based therapy for cartilage repair. To promote understanding of the molecular control of chondrogenesis differentiation in MSCs, we compared the changes in microRNAs during in vitro chondrogenesis process of human bone-marrow mesenchymal stem cells (hBMSCs). MiR-199b-5p was up-regulated significantly during this process. The aim of the study was to investigate the effects of miR-199b-5p on chondrogenic differentiation of C3H10T1/2 MSC cells and explore the underlying mechanisms. MiR-199b-5p mimics or inhibitor were transfected into C3H10T1/2 cells, respectively, and then, the effects of miR-199b-5p on chondrogenic differentiation of C3H10T1/2 cells were detected. The results indicated that miR-199b-5p overexpression inhibited the growth of C3H10T1/2 cells but promoted transforming growth factor-β3 (TGF-β3)-induced C3H10T1/2 cells of chondrogenic differentiation, as supported by enhancing the gene and protein expression of chondrocyte specific markers of SOX9, aggrecan, and collagen type II (Col2a1). In contrast, inhibiting miR-199b-5p notably promoted the proliferation of C3H10T1/2 cells but decreased chondrogenic differentiation. Furthermore, mechanism studies revealed that JAG1 was a direct target of miR-199b-5p by dual luciferase reporter assays. While silencing of JAG1 by isRNA resulted an increase of chondrogenic differentiation. Further, JAG1 knockdown was demonstrated to block the effect of miR-199b-5p inhibition. In conclusion, the present study revealed for the first time that miR-199b-5p was the positive regulators to modulate chondrogenic differentiation of C3H10T1/2 cells by targeting JAG1. These findings may provide a novel insight on miRNA-mediated MSC therapy for cartilage related disorders.

Effects of Conditioned Medium From Osteoarthritic Cartilage Fragments on Donor-Matched Infrapatellar Fat Pad-Derived Mesenchymal Stromal Cells

BACKGROUND

Mesenchymal stromal cell (MSC)-based therapies have emerged as a promising strategy for osteoarthritis (OA) treatment. In particular, infrapatellar fat pad (IPFP)-derived MSCs have become a good option to treat knee OA.

PURPOSE

To investigate the influence of the local microenvironment of the knee joint, especially OA cartilage, on the bioactivities of injected/implanted IPFP MSCs.

STUDY DESIGN

Controlled laboratory study.

METHODS

Conditioned medium (CM) derived from OA cartilage fragments was collected and characterized. Donor-matched IPFP MSCs were treated with control medium (Dulbecco's modified Eagle medium (DMEM)/F-12 or chondrogenic medium), control medium + CM, or CM alone; and a series of behaviors including the viability, migration, chondrogenic and hypertrophic differentiation, and catabolic activity of IPFP MSCs were evaluated among groups.

RESULTS

There were 14 cytokines detected in CM. CM treatment improved the viability of IPFP MSCs. CM hindered the migration of IPFP MSCs. In chondrogenic differentiation, the presence of CM increased the expression of chondrogenic markers but also enhanced the state of hypertrophy and catabolism.

CONCLUSION

OA cartilage-secreted factors could induce chondrogenic differentiation but also resulted in negative effects including the weakened migration, increased hypertrophy, and catabolism of IPFP MSCs in vitro.

CLINICAL RELEVANCE

These findings provide an insight on the fate of IPFP MSCs after intra-articular injections.

Therapeutic potential of microRNAs in osteoporosis function by regulating the biology of cells related to bone homeostasis

MicroRNAs (miRNAs) are novel regulatory factors that play important roles in numerous cellular processes through the posttranscriptional regulation of gene expression. Recently, deregulation of the miRNA-mediated mechanism has emerged as an important pathological factor in osteoporosis. However, a detailed molecular mechanism between miRNAs and osteoporosis is still not available. In this review, the roles of miRNAs in the regulation of cells related to bone homeostasis as well as miRNAs that deregulate in human or animal are discussed. Moreover, the miRNAs that act as clusters in the biology of cells in the bone microenvironment and the difference of some important miRNAs for bone homeostasis between bone and other organs are mentioned. Overall, miRNAs that contribute to the pathogenesis of osteoporosis and their therapeutic potential are considered.

Interleukin‑1β‑mediated suppression of microRNA‑27a‑3p activity in human cartilage via MAPK and NF‑κB pathways: A potential mechanism of osteoarthritis pathogenesis

The aim of the present study was to investigate the role of microRNA (miR)‑27a‑3p in osteoarthritis (OA). Reverse transcription‑quantitative polymerase chain reaction and western blotting were performed to determine the expression of miR‑27a‑3p and aggrecanase‑2 (ADAMTS5) in cartilage tissues from patients with OA and healthy controls, and also in interleukin (IL)‑1β‑treated primary human chondrocytes. Primary human chondrocytes were transfected with miR‑27a‑3p. A luciferase reporter assay was used to validate the direct contact between miR‑27a‑3p and its putative binding site in the 3'‑untranslated region ADAMTS5 mRNA. Furthermore, the effects of IL‑1β‑induced activation of mitogen‑activated protein kinase (MAPK) and nuclear factor (NF)‑κB on miR‑27a‑3p were evaluated using specific inhibitors. The results revealed that the level of miR‑27a‑3p was reduced in OA cartilage tissues compared with those of normal controls. In addition, decreased miR‑27a‑3p and increased ADAMTS5 expression was observed in a time‑ and dose‑dependent manner in chondrocytes treated with IL‑1β. Furthermore, overexpression of miR‑27a‑3p suppressed the expression of ADAMTS5 in human chondrocytes induced by IL‑1β. miR‑27a‑3p overexpression also decreased the luciferase activity of the wild‑type ADAMTS5 reporter plasmid. Mutation of the miR‑27a‑3p binding site in the 3'‑untranslated region of ADAMTS5 mRNA abolished the miR‑27a‑3p‑mediated repression of reporter activity. Furthermore, the use of specific inhibitors demonstrated that IL‑1β may regulate miR‑27a‑3p expression via NF‑κB and MAPK signaling pathways in chondrocytes. The present study concluded that miR‑27a‑3p was downregulated in human OA and was suppressed by IL‑1β, and functions as a crucial regulator of ADAMTS5 in OA chondrocytes. In addition, IL‑1β‑mediated suppression of miR‑27a‑3p activity may occur via the MAPK and NF‑κB pathways. The present study may provide a novel strategy for clinical treatment of OA caused by upregulation of miR‑27a‑3p.