Enhanced osteoprogenitor elongated collagen fiber matrix formation by bioactive glass ionic silicon dependent on Sp7 (osterix) transcription

Abstract

Bioactive glasses release ions, those enhance osteoblast collagen matrix synthesis and osteogenic marker expression during bone healing. Collagen matrix density and osteogenic marker expression depend on osteogenic transcription factors, (e.g., Osterix (OSX)). We hypothesize that enhanced expression and formation of collagen by Si(4+) depends on enhanced expression of OSX transcription. Experimental bioactive glass (6P53-b) and commercial Bioglass(TM) (45S5) were dissolved in basal medium to make glass conditioned medium (GCM). ICP-MS analysis was used to measure bioactive glass ion release rates. MC3T3-E1 cells were cultured for 20 days, and gene expression and extracellular matrix collagen formation was analyzed. In a separate study, siRNA was used to determine the effect of OSX knockdown on impacting the effect of Si(4+) on osteogenic markers and matrix collagen formation. Each bioactive glass exhibited similar ion release rates for all ions, except Mg(2+) released by 6P53-b. Gene expression results showed that GCM markedly enhanced many osteogenic markers, and 45S5 GCM showed higher levels of expression and collagen matrix fiber bundle density than 6P53-b GCM. Upon knockdown of OSX transcription, collagen type 5, alkaline phosphatase, and matrix density were not enhanced as compared to wild type cells. This study illustrates that the enhancement of elongated collagen fiber matrix formation by Si(±) depends on OSX transcription. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 2604-2615, 2016.

In Vitro Human Umbilical Vein Endothelial Cells Response to Ionic Dissolution Products from Lithium-Containing 45S5 Bioactive Glass

“…In addition, IGF1 is involved in the activation of β-catenin [ 54 , 55 , 56 ], generating a positive feedback circuit that contributes to the proliferation, migration, and survival of endothelial cells [ 24 , 25 , 26 , 27 ]. On the other hand, it is important to point out that Si and Li + ions also promote osteogenesis and bone repair [ 18 , 19 , 50 , 63 , 64 , 65 , 66 , 67 , 68 , 69 ]. It would be therefore of interest to further evaluate the angiogenic and osteogenic effects of 45S5.5Li particles of different sizes (nano- and micrometric) and/or scaffolds derived from the bioactive glass 45S5.5Li by using more complex cell cultures such as the co-culture of osteoblasts with endothelial cells, as well as in experimental models of bone repair in vivo.…”

Biological Effects of a Three-Dimensionally Printed Ti6Al4V Scaffold Coated with Piezoelectric BaTiO3 Nanoparticles on Bone Formation

“…Osterix, a zinc finger transcription factor, is widely accepted as a master osteogenic factor. The essential role of osterix in osteogenesis relies on its ability to regulate the expression of a number of osteoblast markers, such as osteopontin, Dkk1, and collagen type I. − The above results have confirmed that the piezoelectric effect can effectively promote the upregulation of osterix gene expression. Therefore, our study further clarifies the mechanism of osterix upregulation.…”

In vitro evaluation of novel low-pressure spark plasma sintered HA–BG composite scaffolds for bone tissue engineering

“…This amplied OSX expression may be associated with the presence of an increased glassy phase (Si) and enhanced Ca dissolution in HB 30 S. This was supported by a previous nding, where commercial Bioglass™ (45S5)-conditioned media signicantly induced OSX and osteogenic differentiation of the MC3T3-E1 calvaria cell line. 73…”