Effects of integrin metalloproteinases on osteogenic differentiation / 北京大学学报(医学版)

OBJECTIVE@#To study the effects of disintegrin and metalloproteinase (ADAM) 9, 15 and 17 on the osteogenic differentiation of bone marrow mesenchymal stem cells (BMMSCs).@*METHODS@#BMMSCs of ADAM9, ADAM15, ADAM17 conditional knockout mice and wild type mice (WT) were induced and cultured. Alkaline phosphatase (ALP) activity was measured by colorimetry, early osteogenic transcription factors Runx and Osterix were detected by Real-time PCR, and mineral formation was analyzed by alizarin red staining.@*RESULTS@#ALP activity was lower in ADAM9 group (8.08±0.34), ADAM15 group (6.46±3.40), ADAM17 group (9.30±2.30) than that in WT group (9.44±2.50), but there was no significant difference (P>0.05). Stimulated with bone morphogenetic protein 2(BMP2),there was significant difference (P<0.05) between ADAM9 group (14.22±3.25), ADAM15 group (10.14±2.40) and WT group (20.89±3.40), and ADAM 17 group (23.56±2.50) was higher than WT group (20.89±3.40), but no significant difference (P>0.05). Similarly, cultured by osteogenic induction medium (OST), compared with WT group (12.97±1.30), ADAM9 group (9.63±1.00) and ADAM15 group (7.75±1.30) were lower, ADAM17 group (20.09±1.68) was higher, and the difference was statistically significant (P<0.05). Using stimulated culture by BMP2 and OST combined, ADAM9 group (15.75±1.30), ADAM 15 group (12.43±1.30) were less than WT group (26.15 ±1.50), while ADAM17 group (29.55±2.10) was higher than WT group were statistically significant (P<0.05). The expression of Runx2 in ADAM9 group (2.02±0.24), ADAM15 group (3.09±0.19), ADAM17 group (3.89±0.91) had no significant difference compared with WT (2.02±0.21) group (P>0.05). ADAM9 group stimulated by BMP2 (7.00±0.23), ADAM15 group (6.04±0.23) were lower than WT group (12.6±0.23), ADAM17 group (18.52±1.39) was higher than WT group (12.6±0.23), and the difference was statistically significant (P<0.05). In non-stimulating culture, there was no significant difference in Osterix expression between ADAM9 group (9.60±3.87), ADAM17 group (12.40±3.00) and WT group (10.9±1.10, P>0.05), but in ADAM15 group (6.50±1.51) it was slightly lower than that in WT group (P<0.05). After BMP2 stimulation, ADAM9 group (39.20±3.23) and ADAM15 group (20.50±4.80) were less than WT group (60.30±5.93), while ADAM17 group (80.20±3.30) was higher than WT group (P<0.05). Alizarin red staining showed no obvious orange-red mass in the non-induction group. Local calcified nodules could be seen in the BMP2, OST, OST + BMP2 induction culture conditions in all the experimental groups, but there was no significant difference in quantitative analysis (P>0.05).@*CONCLUSION@#ADAM9, 15, 17 took part in the osteogenic differentiation of BMMSCs, and provided new targets for its regulation.

Decreased plasma ADAMTS-13 activity as a predictor of postoperative bleeding in cyanotic congenital heart disease

OBJECTIVE: To analyze the preoperative plasma antigenic concentration and activity of von Willebrand factor and its main cleaving protease ADAMTS-13 in pediatric patients with cyanotic congenital heart disease undergoing surgical treatment and investigate possible correlations with postoperative bleeding. METHODS: Plasma antigenic concentrations (von Willebrand factor:Ag and ADAMTS-13:Ag) were measured using enzyme-linked immunoassays. Collagen-binding assays were developed to measure biological activities (von Willebrand factor:collagen binding and ADAMTS-13 activity). The multimeric structure of von Willebrand factor was analyzed using Western immunoblotting. Demographic, diagnostic, and general and specific laboratory data and surgery-related variables were subjected to univariate, bivariate, and multivariate analysis for the prediction of postoperative bleeding. RESULTS: Forty-eight patients were enrolled, with ages ranging from 9 months to 7.6 years (median 2.5 years). The plasma concentrations of von Willebrand factor:Ag and ADAMTS-13:Ag were decreased by 65 and 82%, respectively, in the patients compared with the controls (p<0.001). An increased density of low-molecular-weight fractions of von Willebrand factor, which are suggestive of proteolytic degradation (p = 0.0081), was associated with decreased ADAMTS-13 activity, which was likely due to ADAMTS-13 consumption (71% of controls, p = 0.0029) and decreased von Willebrand factor:collagen binding (76% of controls, p = 0.0004). Significant postoperative bleeding occurred in 13 patients. The preoperative ADAMTS-13 activity of <64.6% (mean level for the group), preoperative activated partial thromboplastin time, and the need for cardiopulmonary bypass were characterized as independent risk factors for postoperative bleeding, with respective hazard ratios of 22.35 (95% CI 1.69 to 294.79), 1.096 (95% CI 1.016 to 1.183), and 37.43 (95% ...

Molecular correlates of syncytialization in muscle and placenta.

Syncytialization is one of the most fundamental processes in life. It is observed during development of muscle and osteoclast, and syncytiotrophoblast formation in placental villi. Syncytialization involves recognition, migration, adhesion and finally cell fusion between two interacting cells. It is an energy-dependent process which is essentially restricted to a small portion of interacting cellular membranes. Such regions of membranes may differ from other regions of cell surface in terms of physico-chemistry and expression of specific protein biomolecules resulting in restriction of this process to cells of specific competence. Despite the fact that membrane biologists have given significant quanta of efforts to understand the basic principle underlying this fundamental process of life, further large scale initiatives have to be undertaken to dissect the underlying molecular correlates central to this event.