Cell-derived matrices (CDM)-Methods, challenges and applications.

Extracellular matrix (ECM) provides both physical support and bioactive signals such as growth factors and cytokines to cells at their microenvironment or niche. Engineering the matrix niche becomes an important approach to study or manipulate cellular fate. This work presents an overview on the reconstitution of the ECM niche through a wide range of approaches ranging from coating culture dish with ECM molecules to decellularization of native tissues. In particular, we focused on reconstituting the complex ECM niche through cell-derived matrix (CDM) by reviewing the methodological approaches used in our group to derive ECM from mature cells such as chondrocytes and nucleus pulposus cells (NPCs), undifferentiated stem cells such as mesenchymal stem cells (MSCs), as well as MSCs undergoing chondrogenic and osteogenic differentiation, in 2D or 3D models. Specific attention has also been given to key factors that should be considered in various applications and challenges in relation to the CDM. Last but not the least, a few future perspectives and their significance have been proposed.

[Study on the influence of Wnt3a on osteogenetic differentiation ability of dental pulp stem cells induced by mineralizing medium].

Objective: To investigate the effects of Wnt3a protein on proliferation and osteogenic differentiation of human dental pulp stem cells(DPSC). Methods: Intact human permanent teeth extracted for orthodontic reasons were collected and used as study models. The biological effects of Wnt3a on DPSC were investigated using methyl thiazolyl tetrazolium(MTT), alkaline phosphatase(ALP) activity assay, alizarin red S staining and realtime fluorescence quantitative PCR. Osteogenic-related gene expression of induced DPSC was examinedby using tests of bone sialoprotein(BSP), osteocalcin(OCN), collagen type Ⅰ (COL-Ⅰ) and Runt-related transcription factor 2(RUNX-2). Results: Wnt3a proteininduced an increase of cell growth and treatment of DPSC with Wnt3a induced a highest increase in cell growth at the concentration of 5 µg/L. 5 µg/L Wnt3a proteins combined with the osteogenic medium treatment caused up-regulated osteogenic differentiation, ALP activity and express of osteogenic-related genes of DPSC, and the ALP activity(0.47±0.04) was significantly stronger than the other groups(osteogenic medium: 0.39±0.05; 20 µg/L: 0.34±0.03; 50 µg/L: 0.27±0.07; 100 µg/L: 0.20±0.03). Conclusions: Exogenous Wnt3a protein treatment on DPSC could affect the proliferation and osteogenic differentiation.