To study the cartilage differentiation of mouse mesenchymal stem cells (MSCs) induced by cartilage-derived morphogenetic proteins-2 in vitro, the MSCs were isolated from mouse bone marrow and cultured in vitro. The cells in passage 3 were induced into chondrogenic differentiation with different concentrations of recombinant human cartilage-derived morphogenetic proteins-2 (0, 10, 20, 50 and 100 ng/mL). After 14 days of induction, morphology of cells was observed under phase-contrast microscope. Collagen II mRNA and protein were examined with RT-PCR, Western blotting and immunocytochemistry respectively and the sulfate glycosaminoglycan was measured by Alcian blue staining. RT-PCR showed that CDMP-2 could promote expression of collagen II mRNA in an dose-dependant manner, especially at the concentration of 50 ng/mL and 100 ng/mL. Immunocytochemistry and Western blotting revealed a similar change. Alcian blue staining exhibited deposition of typical cartilage extracellular matrix. Our results suggest that mouse bone marrow mesenchymal stem cells can differentiate into chondrogenic phonotype with the induction of CDMP-2 in vitro, which provides a basis for further research on the role of CDMP-2 in chondrogenesis.
Bone Marrow Cells/*cytology ; Bone Morphogenetic Proteins/*pharmacology ; Cell Differentiation/*drug effects ; Cells, Cultured ; Chondrocytes/*cytology ; Chondrogenesis/drug effects ; Chondrogenesis/physiology ; Mesenchymal Stem Cells/*cytology ; Recombinant Proteins/pharmacology

Due to the poor repair ability of cartilage tissue, regenerative medicine still faces great challenges in the repair of large articular cartilage defects. Quercetin is widely applied as a traditional Chinese medicine in tissue regeneration including liver, bone and skin tissues. However, the evidence for its effects and internal mechanisms for cartilage regeneration are limited. In the present study, the effects of quercetin on chondrocyte function were systematically evaluated by CCK8 assay, PCR assay, cartilaginous matrix staining assays, immunofluorescence assay, and western blotting. The results showed that quercetin significantly up-regulated the expression of chondrogenesis genes and stimulated the secretion of GAG (glycosaminoglycan) through activating the ERK, P38 and AKT signalling pathways in a dose-dependent manner. Furthermore, in vivo experiments revealed that quercetin-loaded silk protein scaffolds dramatically stimulated the formation of new cartilage-like tissue with higher histological scores in rat femoral cartilage defects. These data suggest that quercetin can effectively stimulate chondrogenesis in vitro and in vivo, demonstrating the potential application of quercetin in the regeneration of cartilage defects.
Animals ; Cartilage/cytology* ; Chondrocytes/drug effects* ; Chondrogenesis/drug effects* ; Extracellular Matrix/metabolism* ; Quercetin/pharmacology* ; Rats ; Signal Transduction/drug effects* ; Tissue Scaffolds

OBJECTIVETo investigate the effect of recombinant adenovirus-mediated bone morphogenetic protein (BMP)-2 and -3 over expressions on chondrogenesis and osteogenesis of prenatal mouse intervertebral disc cells and provide experimental evidences for the application of BMPs in the therapy of disc diseases.

METHODSThe prenatal mouse intervertebral disc cells were infected with a recombinant adenovirus expressing BMP-2 and BMP-3 for 5-7 days, and the expressions of collagen type I (Col I), collagen type II (Col II), aggrecan, osteocalcin, osteoprotegerin and osteopontin mRNAs were detected with RT-PCR. The expression of cartilage matrix was evaluated with toluidine blue staining, and alkaline phosphatase (ALP) activity was detected with ALP reading and ALP staining.

RESULTSBMP-2 and -3 overexpression did not enhance chondrogenesis and osteogenesis of annulus fibrosus (AF) cells or cause significant increases in the expressions of Col I, Col II or aggrecan mRNA in nucleus pulposus (NP) cells. Adenovirus-mediated overexpression of BMP-2 and BMP-3, however, promoted osteogenesis of NP cells and significantly increased the expression of osteocalcin mRNA; the overexpression of BMP-2, but not BMP-3, enhanced the mRNA expressions of osteoprotegerin and osteopontin. Toluidine blue staining demonstrated that BMP-2 and BMP-3 overexpression did not obviously affect the secretion of cartilage matrix. In NP cells, BMP-2 and -3 overexpression significantly enhanced ALP activity, which was not observed in AF cells.

CONCLUSIONAdenovirus-mediated BMP-2 and -3 overexpression can promote the osteogenic differentiation of NP cells but can not affect osteogenesis of AF cells or chondrogenesis of NP cells.

Animals ; Bone Morphogenetic Protein 2 ; pharmacology ; Bone Morphogenetic Protein 3 ; pharmacology ; Cell Differentiation ; drug effects ; Cells, Cultured ; Chondrogenesis ; Intervertebral Disc ; cytology ; drug effects ; Mice ; Osteogenesis

Actin cytoskeleton has been known to control and/or be associated with chondrogenesis. Staurosporine and cytochalasin D modulate actin cytoskeleton and affect chondrogenesis. However, the underlying mechanisms for actin dynamics regulation by these agents are not known well. In the present study, we investigate the effect of staurosporine and cytochalasin D on the actin dynamics as well as possible regulatory mechanisms of actin cytoskeleton modulation. Staurosporine and cytochalasin D have different effects on actin stress fibers in that staurosporine dissolved actin stress fibers while cytochalasin D disrupted them in both stress forming cells and stress fiber-formed cells. Increase in the G-/F-actin ratio either by dissolution or disruption of actin stress fiber is critical for the chondrogenic differentiation. Cytochalasin D reduced the phosphorylation of cofilin, whereas staurosporine showed little effect on cofilin phosphorylation. Either staurosporine or cytochalasin D had little effect on the phosphorylation of myosin light chain. These results suggest that staurosporine and cytochalasin D employ different mechanisms for the regulation of actin dynamics and provide evidence that removal of actin stress fibers is crucial for the chondrogenic differentiation.
Actin Cytoskeleton/*drug effects ; Actins/metabolism ; Animals ; Cell Differentiation/*drug effects ; Cells, Cultured ; Chickens ; Chondrogenesis/*drug effects ; Cytochalasin D/*pharmacology ; Mesoderm/cytology/drug effects ; Myosin Light Chains/metabolism ; Nucleic Acid Synthesis Inhibitors/*pharmacology ; Phosphorylation ; Staurosporine/*pharmacology ; Stress Fibers/drug effects

Vertically aligned, laterally spaced nanoscale titanium nanotubes were grown on a titanium surface by anodization, and the growth of chondroprogenitors on the resulting surfaces was investigated. Surfaces bearing nanotubes of 70 to 100 nm in diameter were found to trigger the morphological transition to a cortical actin pattern and rounded cell shape (both indicative of chondrocytic differentiation), as well as the up-regulation of type II collagen and integrin beta4 protein expression through the down-regulation of Erk activity. Inhibition of Erk signaling reduced stress fiber formation and induced the transition to the cortical actin pattern in cells cultured on 30-nm-diameter nanotubes, which maintained their fibroblastoid morphologies in the absence of Erk inhibition. Collectively, these results indicate that a titanium-based nanotube surface can support chondrocytic functions among chondroprogenitors, and may therefore be useful for future cartilaginous applications.
Animals ; Apoptosis ; Cell Differentiation/*drug effects ; Cells, Cultured ; Chick Embryo ; Chickens ; Chondrocytes/cytology/drug effects/metabolism ; Chondrogenesis/*drug effects ; Collagen Type II/metabolism ; Immunohistochemistry ; Integrin beta4/metabolism ; Mesenchymal Stem Cells/*cytology/*drug effects/metabolism ; Nanotubes/*chemistry ; Titanium/*chemistry/*pharmacology

Curcumin is a well known natural polyphenol product isolated from the rhizome of the plant Curcuma longa, anti-inflammatory agent for arthritis by inhibiting synthesis of inflammatory prostaglandins. However, the mechanisms by which curcumin regulates the functions of chondroprogenitor, such as proliferation, precartilage condensation, cytoskeletal organization or overall chondrogenic behavior, are largely unknown. In the present report, we investigated the effects and signaling mechanism of curcumin on the regulation of chondrogenesis. Treating chick limb bud mesenchymal cells with curcumin suppressed chondrogenesis by stimulating apoptotic cell death. It also inhibited reorganization of the actin cytoskeleton into a cortical pattern concomitant with rounding of chondrogenic competent cells and down-regulation of integrin beta1 and focal adhesion kinase (FAK) phosphorylation. Curcumin suppressed the phosphorylation of Akt leading to Akt inactivation. Activation of Akt by introducing a myristoylated, constitutively active form of Akt reversed the inhibitory actions of curcumin during chondrogenesis. In summary, for the first time, we describe biological properties of curcumin during chondrogenic differentiation of chick limb bud mesenchymal cells. Curcumin suppressed chondrogenesis by stimulating apoptotic cell death and down-regulating integrin-mediated reorganization of actin cytoskeleton via modulation of Akt signaling.
Animals ; Anti-Inflammatory Agents, Non-Steroidal/*pharmacology ; Apoptosis/drug effects ; Cells, Cultured ; Chick Embryo ; Chondrogenesis/*drug effects ; Curcumin/*pharmacology ; Cytoskeleton/*drug effects/metabolism ; Limb Buds/*cytology ; Mesenchymal Stem Cells/cytology/*drug effects ; Proto-Oncogene Proteins c-akt/metabolism

OBJECTIVETo investigate the feasibility that transforming growth factor-beta1 (TGF-beta1) -loaded fibrin sealant (FS) promotes bone marrow mesenchymal stem cells (BMSCs) to create tissue engineering cartilage in vivo.

METHODSThe BMSCs were isolated from healthy human and amplified in vitro, and then induced by defined medium containing TGF-beta1 and dexamethasone. After 7 days the induced BMSCs were collected and mixed with TGF-beta1-loaded FS or FS as BMSCs+ FS-TGF-beta1 group and BMSCs+ FS experimental group. Then the mixture was injected by a needle into the dorsum of nude mice. In control group, only FS or BMSCs were injected. The tissue engineering specimens were harvested from nude mice 12 weeks later. Gross observation, average wet weight measurement, glycosaminoglycan (GAG) quantification, histology and immunohistochemistry were used to evaluate the results.

RESULTSThe BMSCs have possessed the shape and functional characters of chondrocyte when transferred to a defined medium. After injection of the mixture, the cartilage-like tissue were formed in two experimental groups. Compared with BMSC+ FS group, the specimens of BMSCs +FS-TGF-beta1 group were larger and firmer. Alcian staining showed better metachromatic matrix formation. The GAG contents were significantly higher. Immunohistochemical staining of collagen type II was stronger. However, no cartilage-like tissue was formed in two control groups.

CONCLUSIONTGF-beta1-loaded FS can promote BMSCs to contract injectable tissue engineering cartilage in vivo.

Animals ; Biocompatible Materials ; Cell Differentiation ; drug effects ; Cells, Cultured ; Chondrogenesis ; drug effects ; Dexamethasone ; pharmacology ; Fibrin Tissue Adhesive ; Humans ; Mesenchymal Stromal Cells ; cytology ; drug effects ; Mice ; Mice, Inbred BALB C ; Mice, Nude ; Tissue Engineering ; methods ; Transforming Growth Factor beta ; pharmacology

BACKGROUNDSynovium-derived stem cells (SDSCs) with higher chondrogenic potential are attracting considerable attention as a cell source for cartilage regeneration. We investigated the effect of bone morphogenetic protein 2 (BMP-2) on transforming growth factor beta3 (TGF-β3)-induced chondrogenesis of SDSCs isolated from human osteoarthritic synovium in a pellet culture system.

METHODSThe clonogenicity, stem cell marker expression and multi-differentiation potential of isolated SDSCs were determined by colony forming unit assay, flow cytometry and specific staining including alizarin red S, Oil red O and alcian blue staining, respectively. SDSCs pellet was cultured in chondrogenic medium with or without TGF-β3 or/and BMP-2. At day 21, the diameter and the weight of the pellets were measured. Chondrogenic differentiation of SDSCs was evaluated by Safranin O staining, immunohistochemical staining of collagen type II, sulfated glycosaminoglycan (sGAG) synthesis and mRNA expression of collagen type II, aggrecan, SOX9, link-protein, collagen type X and BMP receptor II.

RESULTSCells isolated under the optimized culturing density (10(4)/60 cm(2)) showed clonogenicity and multi-differentiation potential. These cells were positive (> 99%) for CD44, CD90, CD105 and negative (< 10%) for CD34 and CD71. SDSCs differentiated to a chondrocytic phenotype in chondrogenic medium containing TGF-β3 with or without BMP-2. Safranin O staining of the extracellular matrix was positive and the expression of collagen type II was detected. Cell pellets treated with TGF-β3 and BMP-2 were larger in diameter and weight, produced more sGAGs, and expressed higher levels of collagen type II and other chondrogenic markers, except COL10A1, than medium with TGF-β3 alone.

CONCLUSIONSSDSCs could be isolated from human osteoarthritic synovium. Supplementation with BMP-2 significantly promoted the in vitro TGF-β3-induced chondrogenic differentiation of SDSCs.

Aged ; Bone Morphogenetic Protein 2 ; pharmacology ; Cell Differentiation ; drug effects ; Cells, Cultured ; Chondrogenesis ; drug effects ; Female ; Humans ; Immunohistochemistry ; Male ; Mesenchymal Stromal Cells ; cytology ; drug effects ; Middle Aged ; Synovial Membrane ; cytology ; Transforming Growth Factor beta3 ; pharmacology

Articular cartilage, which is mainly composed of collagen II, enables smooth skeletal movement. Degeneration of collagen II can be caused by various events, such as injury, but degeneration especially increases over the course of normal aging. Unfortunately, the body does not fully repair itself from this type of degeneration, resulting in impaired movement. Microfracture, an articular cartilage repair surgical technique, has been commonly used in the clinic to induce the repair of tissue at damage sites. Mesenchymal stem cells (MSC) have also been used as cell therapy to repair degenerated cartilage. However, the therapeutic outcomes of all these techniques vary in different patients depending on their age, health, lesion size and the extent of damage to the cartilage. The repairing tissues either form fibrocartilage or go into a hypertrophic stage, both of which do not reproduce the equivalent functionality of endogenous hyaline cartilage. One of the reasons for this is inefficient chondrogenesis by endogenous and exogenous MSC. Drugs that promote chondrogenesis could be used to induce self-repair of damaged cartilage as a non-invasive approach alone, or combined with other techniques to greatly assist the therapeutic outcomes. The recent development of human induced pluripotent stem cell (iPSCs), which are able to self-renew and differentiate into multiple cell types, provides a potentially valuable cell resource for drug screening in a "more relevant" cell type. Here we report a screening platform using human iPSCs in a multi-well plate format to identify compounds that could promote chondrogenesis.
Cell Differentiation ; drug effects ; Chondrocytes ; cytology ; drug effects ; metabolism ; Chondrogenesis ; drug effects ; Drug Evaluation, Preclinical ; methods ; Genes, Reporter ; genetics ; Humans ; Induced Pluripotent Stem Cells ; cytology ; drug effects ; metabolism ; Keratinocytes ; cytology ; drug effects ; metabolism ; Luciferases ; genetics ; Peptides ; chemical synthesis ; metabolism ; Reproducibility of Results ; Small Molecule Libraries ; pharmacology

It is widely known that hypoxia can promote chondrogenesis of human bone marrow derived mesenchymal stem cells (hMSCs) in monolayer cultures. However, the direct impact of oxygen tension on hMSC differentiation in three-dimensional cultures is still unknown. This research was designed to observe the direct impact of oxygen tension on the ability of hMSCs to "self assemble" into tissue-engineered cartilage constructs. hMSCs were cultured in chondrogenic medium (CM) containing 100 ng/mL growth differentiation factor 5 (GDF-5) at 5% (hypoxia) and 21% (normoxia) O2 levels in monolayer cultures for 3 weeks. After differentiation, the cells were digested and employed in a self-assembly process to produce tissue-engineered constructs under hypoxic and normoxic conditions in vitro. The aggrecan and type II collagen expression, and type X collagen in the self-assembled constructs were assessed by using immunofluorescent and immunochemical staining respectively. The methods of dimethylmethylene blue (DMMB), hydroxyproline and PicoGreen were used to measure the total collagen content, glycosaminoglycan (GAG) content and the number of viable cells in each construct, respectively. The expression of type II collagen and aggrecan under hypoxic conditions was increased significantly as compared with that under normoxic conditions. In contrast, type X collagen expression was down-regulated in the hypoxic group. Moreover, the constructs in hypoxic group showed more significantly increased total collagen and GAG than in normoxic group, which were more close to those of the natural cartilage. These findings demonstrated that hypoxia enhanced chondrogenesis of in vitro, scaffold-free, tissue-engineered constructs generated using hMSCs induced by GDF-5. In hypoxic environments, the self-assembled constructs have a Thistological appearance and biochemical parameters similar to those of the natural cartilage.
Aggrecans ; genetics ; metabolism ; Bone Marrow Cells ; drug effects ; metabolism ; Cartilage ; cytology ; metabolism ; Cell Differentiation ; drug effects ; genetics ; Cell Hypoxia ; Cells, Cultured ; Chondrogenesis ; drug effects ; genetics ; Collagen Type II ; genetics ; metabolism ; Collagen Type X ; metabolism ; Female ; Gene Expression ; drug effects ; Glycosaminoglycans ; metabolism ; Growth Differentiation Factor 5 ; pharmacology ; Humans ; Immunohistochemistry ; Male ; Mesenchymal Stromal Cells ; drug effects ; metabolism ; Reverse Transcriptase Polymerase Chain Reaction ; Tissue Engineering ; methods