Adseverin, an Actin Binding Protein, Regulates Articular Chondrocyte Phenotype.
Authors of this article are:
Chan B, Parreno J, Glogauer M, Wang Y, Kandel R.
A summary of the article is shown below:
Chondrocytes dedifferentiate as a result of monolayer culture for cell number expansion. This is associated with the development of an elongated shape, increased actin polymerization, development of stress fibers, and expression of contractile molecules. Given the changes in actin status with dedifferentiation, the hypothesis of this study was that adseverin, an actin severing and capping protein, plays a role in regulating chondrocyte phenotype and function. This study reports that serial passaging of articular chondrocytes in monolayer culture resulted in loss of adseverin protein expression as early as day 14 of culture and remained repressed in passage 2 (P2) cells. Knockdown of adseverin by siRNA in primary chondrocytes promoted an increase in cell size and an elongated shape, actin stress fibers, decreased G-/F-actin ratio, and increased number of actin free barbed ends. The cells also showed increased expression of the contractile genes and proteins, vinculin and α-SMA, and increased ability to contract collagen gels. These are all features of dedifferentiation. These effects were due to adseverin as adseverin overexpression following transfection of the GFP-adseverin plasmid partially reversed all of these changes in P2 chondrocytes. Furthermore, sox9 and aggrecan chondrogenic gene expression was upregulated and collagen type I genes expression was downregulated with adseverin overexpression. The change in aggrecan mRNA expression had functional consequence as these cells exhibited increased total proteoglycan synthesis. These findings demonstrate adseverin regulates features indicative of redifferentiation in passaged articular chondrocytes through modulation of the actin cytoskeleton status and potentially may regulate the maintenance of phenotype in primary chondrocytes.This article is protected by copyright. All rights reserved.
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This article is a good source of information and a good way to become familiar with topics such as: Actin binding protein; Adseverin; Chondrocyte; Dedifferentiation; Phenotype; Redifferentiation.