Phosphate regulates chondrogenesis in a biphasic and maturation-dependent manner.

Phosphate regulates chondrogenesis in a biphasic and maturation-dependent manner.
Differentiation. 2017 May 08;95:54-62
Authors: Wu B, Durisin EK, Decker JT, Ural EE, Shea LD, Coleman RM
Abstract
Inorganic phosphate (Pi) has been recognized as an important signaling molecule that modulates chondrocyte maturation and cartilage mineralization. However, conclusive experimental evidence for its involvement in early chondrogenesis is still lacking. Here, using high-density monolayer (2D) and pellet (3D) culture models of chondrogenic ATDC5 cells, we demonstrate that the cell response to Pi does not correlate with the Pi concentration in the culture medium but is better predicted by the availability of Pi on a per cell basis (Pi abundance). Both culture models were treated with ITS+, 10mM β-glycerophosphate (βGP), or ITS+/10mM βGP, which resulted in three levels of Pi abundance in cultures: basal (Pi/DNA <10ng/µg), moderate (Pi/DNA=25.3 - 32.3ng/µg), and high abundance (Pi/DNA >60ng/µg). In chondrogenic medium alone, the abundance levels were at the basal level in 2D culture and moderate in 3D cultures. The addition of 10mM βGP resulted in moderate abundance in 2D and high abundance in 3D cultures. Moderate Pi abundance enhanced early chondrogenesis and production of aggrecan and type II collagen whereas high Pi abundance inhibited chondrogenic differentiation and induced rapid mineralization. Inhibition of sodium phosphate tr...

Source: Differentiation - May 8, 2017 Category: Research Authors: Wu B, Durisin EK, Decker JT, Ural EE, Shea LD, Coleman RM Tags: Differentiation Source Type: research