Initiation of Chondrocyte Self-Assembly Requires an Intact Cytoskeletal Network

Tissue Eng Part A. 2016 Feb;22(3-4):318-25. doi: 10.1089/ten.TEA.2015.0491. Epub 2016 Jan 27.

Abstract

Self-assembly and self-organization have recently emerged as robust scaffold-free tissue engineering methodologies that can be used to generate various tissues, including cartilage, vessel, and liver. Self-assembly, in particular, is a scaffold-free platform for tissue engineering that does not require the input of exogenous energy to the system. Although self-assembly can generate functional tissues, most notably neocartilage, the mechanisms of self-assembly remain unclear. To study the self-assembling process, we used articular chondrocytes as a model to identify parameters that can affect this process. Specifically, the roles of cell-cell and cell-matrix adhesion molecules, surface-bound collagen, and the actin cytoskeletal network were investigated. Using time-lapse imaging, we analyzed the early stages of chondrocyte self-assembly. Within hours, chondrocytes rapidly coalesced into cell clusters before compacting to form tight cellular structures. Chondrocyte self-assembly was found to depend primarily on integrin function and secondarily on cadherin function. In addition, actin or myosin II inhibitors prevented chondrocyte self-assembly, suggesting that cell adhesion alone is not sufficient, but rather the active contractile actin cytoskeleton is essential for proper chondrocyte self-assembly and the formation of neocartilage. Better understanding of the self-assembly mechanisms allows for the rational modulation of this process toward generating neocartilages with improved properties. These findings are germane to understanding self-assembly, an emerging platform for tissue engineering of a plethora of tissues, especially as these neotissues are poised for translation.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Cartilage, Articular / cytology
  • Cartilage, Articular / metabolism*
  • Cattle
  • Chondrocytes / cytology
  • Chondrocytes / metabolism*
  • Cytoskeleton / metabolism*
  • Models, Biological*