Wednesday, August 24, 2011

LSJL and integrin alpha 11

LSJL induces integrin alpha 11 expression.

BMP-2 and TGF-beta1 differentially control expression of type II procollagen and alpha 10 and alpha 11 integrins in mouse chondrocytes.

"The expression of alpha 10 and alpha 11 integrin subunits and the IIA/IIB spliced forms of type II procollagen have been monitored for the first time in parallel in the same in vitro model of mouse chondrocyte dedifferentiation/redifferentiation. We demonstrated that TGF-beta1 stimulates the expression of the non-chondrogenic form of type II procollagen, IIA isoform, and of a marker of mesenchymal tissues, i.e. the alpha 11 integrin subunit. On the contrary, BMP-2 stimulates the cartilage-specific form of type II procollagen, IIB isoform, and a specific marker of chondrocytes, i.e. the alpha 10 integrin subunit. Collectively, our results demonstrate that BMP-2 has a better capability than TGF-beta1 to stimulate chondrocyte redifferentiation and reveal that the relative expressions of type IIB to type IIA procollagens and alpha 10 to alpha 11 integrin subunits are good markers to define the differentiation state of chondrocytes. In addition, adenoviral expression of Smad6, an inhibitor of BMP canonical Smad signaling, did not affect expression of total type II procollagen or the ratio of type IIA and type IIB isoforms in mouse chondrocytes exposed to BMP-2. This result strongly suggests that signaling pathways other than Smad proteins are involved in the effect of BMP-2 on type II procollagen expression."

"the shift from type IIA [Collagen] to type IIB is a sign of chondrocyte differentiation."

"α11 integrin is more characteristic of mesenchymal tissues"

"chondrocytic differentiation of mesenchymal stem cells is associated with an increase in α10 expression and a decrease in α11 expression "<-unfortunately this wasn't observed in LSJL.  Although this could be indicative of pre-chondrogenesis induced by LSJL.  Expression of alpha10 was normal and alpha11 increased.

"BMP-2 primarily stimulates expression of a well-differentiated chondrocytic phenotype whereas TGF-β1 stimulates a pre-chondrocytic phenotype"

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