ObjectiveTo study the immunological properties of osteogenically differentiated umbilical cord blood derived mesenchymal stem cells (UCB-MSCs). MethodsUCB-MSCs were isolated from the umbilical cord vein, and were expanded; the cells at passage 3 were osteogenically induced for 2 weeks in vitro. The expressions of human leukocyte antigen I (HLA-I) and HLA-Ⅱ molecules were observed by flow cytometry analysis before and after osteogenic induction. Peripheral blood T lymphocytes were isolated and cultured with osteoblastic induced or non-osteoblastic induced UCB-MSCs in different cell concentrations of 1×102, 1×103, 1×104, and 1×105 cells/well. The intake value of 3H-thymidine was calculated with luminescence counter. Then T lymphocytes were pretreated with PHA, and co-cultured with osteoblastic induced and non-osteoblastic induced UCB-MSCs as described above. IL-2 was further added to test the reversed effect of T lymphocytes proliferation stimulated by UCB-MSCs. Finally, to investigate whether the immunomodulatory effects on T lymphocytes proliferation depend on direct or indirect cell contact, the Transwell chamber culture system of UCB-MSCs and T lymphocytes was established. ResultsFlow cytometry analysis showed that non-osteoblastic induced UCB-MSCs expressed HLA-I but did not express HLA-Ⅱ; the expression of HLA-Ⅱ increased in osteoblastic induced UCB-MSCs. No T lymphocyte response was stimulated by non-osteoblastic induced UCB-MSCs, but osteoblastic induced UCB-MSCs could stimulate the proliferation of allogeneic T lymphocytes, especially after IFN-γ treatment. Non-osteoblastic induced UCB-MSCs of 1×104 and 1×105 cells/well could suppress the proliferation of T lymphocytes evoked by PHA, and this suppression could be reversed by the addition of IL-2. While osteoblastic induced UCB-MSCs did not have such suppressive effect. The results of the Transwell culture system also showed that non-osteoblastic induced UCB-MSCs could obviously inhibit the proliferation of T lymphocytes, but the osteoblastic induced UCB-MSCs could not. ConclusionThe immunological properties of UCB-MSCs will change accordingly after osteogenic induction, so UCB-MSCs might not be suitable for the seed cells of bone tissue engineering.
ObjectiveTo investigate the role of the forkhead/Fox transcription factor 2 (Foxc2) over-expression in regulating osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) by Wnt-β-catenin signaling pathways in vitro so as to provide the experimental basis for repairing osteonecrosis of the femoral head. MethodsThe recombinant lentivirus carrying green fluorescent protein (group A) or Foxc2 (group B) were used to transfect the fifth generation rabbit BMSCs, and untransfected BMSCs served as a control (group C). The cell viability was measured with water soluble tetrazolium-1 (WST-1) regent at 72 hours after transfection. After 2 weeks of transfection, the expression of β-catenin in BMSCs was detected by real time fluorescence quantitative PCR, Western blot, and immunofluorescence staining. Meanwhile, the β-catenin inhibitors XAV-939 (0, 0.1, and 1.0 μmol/L) was added in group B; at 2 weeks after osteogenic and adipogenic induction, the gene and protein expressions of collagen type I (COL I), osteocalcin (OCN), and peroxisome proliferator activated receptor gamma 2 (PPARγ-2) were detected by real time PCR and Western blot. ResultsWST-1 results showed that the cell viability of group B (130.85%±0.15%) was significantly higher than that of group A (100.45%±0.35%) (t=7.500, P=0.004) at 72 hours after transfection. At 2 weeks after transfection, the gene and protein expressions of β-catenin in group B were significantly higher than those in group A (P<0.01). After XAV-939 was added in group B, the mRNA and protein expressions of OCN and COL I gradually decreased; the mRNA and protein expressions of PPARγ-2 significantly increased (P<0.05), showing a dose-dependent manner. ConclusionThe over-expression of Foxc2 gene in BMSCs may promote osteogenic differentiation by Wnt-β-catenin signaling pathway.
ObjectiveTo investigate the effect of cyclic stretch stress on the osteogenic differentiation of human cartilage endplate-derived stem cells (CESCs). MethodsCESCs were isolated from the endplate cartilage tissues by the method of agarose suspension culture system. The endplate cartilage tissue was harvested for immunohistochemical staining. Flexercell-4000TM Tension Plus system was used to apply cyclic stretch on CESCs at a frequency of 1 Hz and at a stretch rate of 10% for 1, 6, 12, or 24 hours (experimental group). No stretch stress was performed on CESCs in the same culture condition (control group). After mechanical loading, the protein expression of bone morphogenetic protein 2 (BMP-2) was measured by Western blot, and gene expressions of runt-related transcription factor 2 (Runx2), alkaline phosphatase (ALP), and SOX9 were detected by real-time fluorescent quantitative PCR. ResultsImmunohistochemical staining showed BMP-2 protein expression in chondrocytes. The continuous cyclic stretch stress of 10% can increase the expression of BMP-2 protein in CESCs. Significant differences were observed in the expressions of BMP-2 protein (P<0.05) between 2 groups at the other time points except at 1 hour (P>0.05), in a time-dependent manner. The real-time fluorescent quantitative PCR indicated that the gene expressions of Runx2 and ALP showed an increasing tendency with time in the experimental group when compared with the control group, but there was down-regulated expression of SOX9. Significant difference was found in mRNA expressions of Runx2 and ALP at 12 and 24 hours and in mRNA expressions of SOX9 at 6, 12, and 24 hours between 2 groups (P<0.05), in a time-dependent manner. ConclusionCyclic stretch stress may induce osteogenic differentiation of CESCs by regulating the expressions of some genes related osteogenesis in CESCs.
Objective Simvastatin has been reported to be effective on stimulation of bone formation. To investigate the effects of simvastatin on bone formation relative factors of proximal tibia trabecular bone and on osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs). Methods Fourty 1-week-old male Sprague Dawley rats were divided randomly into 2 groups, 20 rats per group. Rats in experimental group received subcutaneous injection of simvastatin [(5 mg/ (kg? d)], and the rats in control group received injection of normal sal ine at the same dose. The expressions of bone morphogenetic protein 2 (BMP-2), matrix metalloproteinase 13 (MMP-13), and vascular endothel ial growth factor (VEGF) of trabecular bone were analyzed in the tibia by immunohistochemical staining at 1 and 3 weeks after injection. BMSCs from the rat femur at 1 and 3 weeks after injection were cultured under condition of osteogenic induction. ALP staining wasperformed on the 14th day after culture; real-time fluorescent quantitative PCR was used to detect the mRNA expressions of BMP-2, Runx2, Osterix, Msx2, Dlx3, and Dlx5 on the 21st day after culture; and von Kossa staining was performed on the 28th day after culture. Results There was no significant difference in the expressions of BMP-2, MMP-13, and VEGF betweenthe experimental group and control group at 1 and 3 weeks after injection (P gt; 0.05). There was no significant difference in the percentages of ALP positively-stained cells between the experimental group and the control group on the 14th day after culture (P gt; 0.05). The mRNA expressions of BMP-2, Runx2, Osterix, Msx2, Dlx3, and Dlx5 in osteogenic differentiation-inducedBMSCs had also no significant difference between the experimental group and the control group at 1 and 3 weeks after culture (P gt; 0.05). No significant difference in biomineral ization was found between the experimental group and control group at 1 and 3 weeks after culture (P gt; 0.05). Conclusion Subcutaneous injection of simvastatin [(5 mg/(kg?d)] for 1 or 3 weekscan affect neither the expressions of bone formation relative factors of proximal tibia trabecular bone nor the osteogenic differentiation of the BMSCs.
ObjectiveTo investigate the effect of tissue interface stiffness change on the spreading, proliferation, and osteogenic differentiation of rat bone marrow mesenchymal stem cells (BMSCs), and to find the suitable stiffness range for stem cell differentiation. MethodsBone marrow of male Sprague Dawley rats (4 weeks old) were selected to isolate and culture BMSCs by whole bone marrow cell adherent method. The third generation BMSCs (1×105 cells/mL) were inoculated into the ordinary culture dishes covered with polyacrylamide hydrophilic gel (PA) which elastic modulus was 1, 4, 10, 40, and 80 kPa (cells seeded on PA), and ordinary culture dish (75 MPa extreme high elastic modulus) as control. Spreading of cells in different stiffness of PA was observed under light microscope. The elastic modulus values of 4, 10, and 40 kPa PA were selected as groups A, B, and C respectively; the ordinary culture dish (75 MPa extreme high elastic modulus) was used as control group (group D). Cell counts was used to detect the growth conditions of BMSCs, alkaline phosphatase (ALP) kit to detect the concentration of ALP, alizarin red staining technique to detect calcium deposition status, and real-time quatitative PCR technique to detect the expressions of bone gla protein (BGP), Runx2, and collagen type I mRNA. ResultsWith increased PA stiffness, BMSCs spreading area gradually increased, especially in 10 kPa and 40 kPa. At 1 and 2 days after culture, the growth rate showed no significant difference between groups (P > 0.05); at 3-5 days, the growth rate of groups B and C was significantly faster than that of groups A and D (P < 0.05), but difference was not statistically significant between groups A and D (P < 0.05); at 5 days, the proliferation of group C was significantly higher than that of group B (P < 0.05). ALP concentrations were (53.69±0.89), (97.30±1.57), (126.60±14.54), and (12.93±0.58) U/gprot in groups A, B, C, and D respectively; groups A, B, and C were significantly higher than group D, and group C was significantly higher than groups A and B (P < 0.05). Alizarin red staining showed that the percentages of calcium nodules was 20.07%±4.24% in group C; group C was significantly higher than groups A, B, and D (P < 0.05). The expression levels of BGP and collagen type I mRNA were significantly higher in groups A, B, and C than group D, and in group C than groups A and B (P < 0.05). The expression level of Runx2 mRNA was significantly higher in groups B and C than group D, and in group C than group B (P < 0.05), but no significant difference was found between groups A and D (P > 0.05). ConclusionPA elastic modulus of 10-40 kPa can promote the proliferation and osteogenic differentiation of BMSCs, and the higher the stiffness, the stronger the promoting effect.
ObjectiveTo evaluate the effect of leucocyte- and platelet-rich plasma (L-PRP) on the osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) in treating avascular necrosis of the femoral head (ANFH) in rabbits. MethodsTwenty-four New Zealand white rabbits (4-6 months old, both genders, weighing 2.0-3.0 kg) were used for the establishment of bilateral ANFH models and divided into 4 groups (n=6). BMSCs were isolated from the bone marrow of iliac crest, cultured and identified. L-PRP was prepared by Landesberg method. Core decompression only (group A), core decompression and L-PRP implantation (group B), core decompression and BMSCs implantation (group C), and core decompression and implantation of BMSCs and L-PRP were performed in 4 groups. To evaluate bone formation and remodeling of the defects, X-ray photography was taken at 2, 4, and 8 weeks postoperatively. The modified Lane-Sandhu scoring system was used to evaluate the bone formation. Two rabbits were sacrificed at 2, 4, 8 weeks after operation to harvest the specimens for histological observation, new blood vessel count and new bone area ratio. ResultsThe observations of radiology and histology displayed different degrees of bone regeneration at bone defect sites in each group. At 2, 4, and 8 weeks postoperatively, the results of Lane-Sandhu X-ray photography scoring, new blood vessel count, and new bone area ratio showed that groups C and D were significantly better than groups A and B, group D was significantly better than group C. and group B was significantly better than group A (P<0.05). ConclusionThese findings demonstrate that L-PRP can promote osteogenic differentiation of BMSCs in treating ANFH in rabbits, and core decompression associated with BMSCs and L-PRP is an effective and feasible method to treat ANFH.
Objective To clarify the trends of expression levels of several up-regulated micro RNA (miRNA) in tissues of atrophic bone nonunion and mRNAs and proteins of their related target genes in osteogenic differentiation of human bone marrow mesenchymal stem cells (hBMSCs), and to explore their biological functions. Methods The hBMSCs were isolated from bone marrow of il iac bone by gradient centrifugation, and cultured. Osteogenic culture medium was used for osteogenic differentiation of the 4th generation of hBMSCs. The changes of corresponding miRNAs, mRNA and protein expression levels of related target genes were observed at 0 hour, 12 hours, 1 day, 2 days, 4 days, 7 days, and 14 days, by quantitative real-time PCR and Western blot. Results In the process of hBMSCs osteogenic differentiation, the mRNA and protein expression levels of osteoblastic target genes [alkal ine phosphatase l iver/bone/kidney (ALPL), bone morphogeneticprotein 2 (BMP-2), and platelet-derived factor alpha polypeptide (PDGF-A)] at most time points increased significantly whencompared with the values at 0 hour except that of BMP-2 decreased at 12 hours and 1 day, with maximum changes at 1 to 7 days. The miRNA expression levels, mRNA and protein expression levels changed significantly at different time points, while the trends of hsa-miRNA-149 and hsa-miRNA-654-5p changes were negatively correlated with the trends of ALPL and BMP-2 mRNA and protein expression changes respectively (P lt; 0.05). There was no obviously negative correlation between the trends of hsa-miRNA-221 change and PDGF-A change (P gt; 0.05). Conclusion In the osteogenic differentiation process of hBMSCs, hsa-miRNA-149 and hsa-miRNA-654-5p are closely related with the mRNA and protein regulation of ALPL and BMP-2, respectively.
To study the method of isolating and culturing synovium-derived MSCs (SMSCs), and to investigate its multiple differentiation potential in vitro. Methods Three 2-month-old Changfeng hybrid swines weighing 8-10 kg (male and female) were used. SMSCs were harvested from the synovium of swine knee joints and cultured in vitro. When the SMSCs at passage 3 reached confluence, basic culture medium was removed, and the multi ple differentiationpotential of SMSCs was demonstrated in specific induction media (experimental group). The cells at passage 3 cultured with basic culture medium served as control group. After 21 days of chondrogenic differentiation, the cells underwent toluidine blue staining, immunohistochemistry staining and real-time fluorescence quantitative PCR detection. After 10 and 21 days of osteogenic differentiation, the cells underwent ALP staining and Al izarin red staining, respectively. After 21 days of adipogenic differentiation, the cells underwent Oil red O staining. Results SMSCs displayed long and thin or polygonal morphology 24 hours after culture. They prol iferated fast 48 hours after culture and presented large number of spindle-shaped cells with few globular cells 72 hours after culture. For the experimental group 21 days after chondrogenic induction, the cells were positive for toluidine blue staining with the formation of Aggrecan outside the cells; the immunohistochemistry staining revealed the expression of Col II; the real-time fluorescence quantitative PCR detection showed that the expressions of Col II A1, Aggrecan and SOX9 mRNA of the experimental group were greater than that of control group (P lt; 0.05). The cells were positive for ALP staining 10 days after osteogenic induction, and positive for Al izarin red staining 21 days after osteogenic induction, with the formation of calcium nodules. Oil red O staining displayed the formation of l i pid droplets inside the cells 21 days after adi pogenic induction. For the control group, the results of all the staining assays were negative except the ALP staining presenting with sl ight positive result. Conclusion SMSCs can be isolated from knee joint of swine and proliferate and differentiate into osteogenic, adi pogenic and chondrogenic cells in vitro. SMSCs may be a promising source of seed cells for tissue engineering.
Objective To investigate the effects of the recombinanthuman bone morphogenetic protein 2 (rhBMP-2) and/or the osteogenic agents on proliferation and expression of the osteoblast phenotype differentiation of the SD rat mesenchymal stem cells（MSCs）. Methods The rat MSCs were cultured in vitro and were randomly divided into the experimental groups(Groups A-I) and the control group. In the experimental group, MSCs were induced by rhBMP2 in different doses (10, 50, 100 and 200 μg/L) in Groups BE, the osteogenic agent alone (Group A) and by the combined use of rhBMP-2 ［in different doses (10,50, 100 and 200 μg/L)］ and the osteogenic agent in Groups F-I. The MTT colorimetric assay was used to evaluate the proliferation, and the activities of alkaline phosphatase (ALP) and osteocalcin (OC) were observed at 3, 6, 9, 12 days, respectively. Results The inverted phase contrast microscopy showed that MSCs by primary culture for 12 hours were adhibited, with a fusiform shape at 48 hours. At 4 days they were polygonal or atractoid, and were spread gyrately or radiately at 6 days. At 10 days, they were spread at the bottom of the bottle.The statistical analysis showed that the expression of the osteoblast phenotype differentiation of MSCs could be induced in the experimental groups. The proliferation of MSCs could be enhanced in a dosedependent manner in GroupsB-E. The expression of the osteoblast phenotype differentiation, which was tested by the activities of ALP and OC, was significantly higher in Groups F-I than in Groups A-E. Conclusion The combined use of rhBMP-2 and the osteogenic agents can enhance the MSC proliferation and induce an expressionand maintenance of the osteoblast phenotype differentiation of the rat MSCs.
ObjectiveTo investigate the specific microRNA (miRNA) in osteogenic and chondrogenic differentiations of C3H10T1/2 cells. MethodsC3H10T1/2 cells were induced to differentiate into osteoblasts and chondrocytes.Specific miRNA more than 2 fold change and 2 average normalized probe signal between C3H10T1/2 and C3H10T1/2-derived osteoblast,and between C3H10T1/2 and C3H10T1/2-derived chondrocytes were screened out by miRNA microarray,and verified by real-time fluorescence quantitative PCR (RT-qPCR). ResultsAlkaline phosphatase expression of osteogenic induced group was significantly higher than that of control group at 7 days after induced (P<0.05).RT-qPCR results showed the expressions of Runx2,serine protease (Sp7),collagen type I,and osteopontin (OPN) genes were significantly increased at 7,14,and 21 days after induced when compared with before induced (P<0.05).Western blot results showed the expressions of Runx2,Sp7,collagen type I,and OPN proteins of osteogenic induced group were significantly higher than those of control group at 21 days after induced (P<0.05).The expressions of SOX9,collagen type Ⅱ,Aggrecan,and Has2 were significantly increased at 5,10,and 15 days after induced when compared with before induced (P<0.05).The expressions of SOX9,collagen type 2,Aggrecan,and Has2 proteins of chondrogenic induced group were significantly higher than those of control group at 15 days after induced (P<0.05).Totally,10 osteogenic and 3 chondrogenic miRNA more than 2 fold change and 2 average normalized probe signal were screened out by miRNA microarray.RT-qPCR results of these specific miRNAs were similar to microarray results except miR-455-3p. ConclusionSpecific miRNAs are screened out by microarray and it is a good foundation for the future study on miRNA functional verification and target gene prediction.