%0 Journal Article
%T Building a Solid Foundation: CCS in Developing Skeleton and the CCN Family Role
%A Herman Yeger
%J Cell Communication and Signaling
%D 2003
%I BioMed Central
%R 10.1186/1478-811x-1-2
%X In its simplest organizational perspective, a committed mesenchyme initiates formation of cartilage where differentiating chondroblasts progress to become chondrocytes and in doing so lay down a highly specialized extracellular matrix. Hypertrophy of one zone of chondrocytes and death through apoptosis set the framework for ensuing stages in osteogenesis, beginning with a scaffold for growing bone, and then vascularization of the territory which then brings in osteoblasts and osteoclasts to initiate formation of trabecular bone further remodeling and therein the development of a second prominent and unique extracellular matrix. The list of morphogenetic factors, growth factors, steroids and key transcription factors that orchestrate this complex process is already extensive and continues to grow, almost mimicking the process itself [1,2]. Outside to inside and vice versa signaling events are critical to the process of cartilage and bone formation since the different cell populations involved must coordinate their activities in order to realize the ultimate anatomical structure. Thus it is not surprising that disruptions in these intricate communications and loss of factors would lead to development of mild to severe abnormalities. Add to this the importance of precise timing of signaling events and attention to physiologically effective concentrations of factors that dictate growth, differentiation and apoptosis, it is evident that specific molecules are needed to assist in 'pacing' the developmental steps. In this first Commentary we highlight a number of reviews and studies that address the complex biology of cartilage and bone formation, a prime example of cell-cell interaction, communication through diffusible factors, and critical signaling pathways of cell behavior that are inimical to the development of the skeleton. While these processes require a variety of growth factors and hormones we bring attention to one member of the CCN family of genes [3], CCN2(CTG
%U http://www.biosignaling.com/content/1/1/2