In this work, we found that sub-toxic Pb concentrations suppressed bone nodule formation and inhibited differentiation in MC3T3-E1 subclone 14 cells, as shown by decreased expression levels of the differentiation markers alkaline phosphatase (ALP), type 1 collagen (COL1), osteocalcin (OC), and runt-related transcription factor 2 (RUNX2).
In vitro experimental results show that in the presence of an external SMF, cell attachment and osteogenic differentiation were significantly improved using the IO-OA/PLGA composites, as indicated by enhanced alkaline phosphatase (ALP) activity, increased mineralized nodule formation, and upregulated bone-associated gene expression (ALP, OCN, and BMP2), in a dose- and time-dependent manner.
The contents and activity of alkaline phosphatase, levels of collagen type I and bone gla protein, and calcium nodule formation were increased significantly after T-614 treated.
HIF1A-AS2 and IL6 improved the expression level of osteoblast markers Runx2, Osterix, and Osteocalcin and also accelerated the formation of calcium nodule and ALP activity, yet miR-665 had opposite effects.
Transfection with shRNAs markedly increased mineralized nodule formation and the osteogenic-related markers ALP and OCN levels in hPDLCs, whereas the overexpression of S100A4 significantly reduced mineralized nodule formation, and increased the matrix degradation enzymes MMP-2 and MMP-13 levels in hPDLCs.
These cells displayed significantly suppressed bone nodule formation and decreased expression of osteoblast markers such as osteocalcin and osteopontin.
The suppression of ATF4 expression by siRNA abrogated osteocalcin expression and mineralized nodule formation by MC3T3-E1 cells induced by bortezomib, indicating a critical role for ATF4 in bortezomib-mediated osteoblastogenesis.