Morales T I, Hascall V C
Bone Research Branch, National Institute of Dental Research, Bethesda, Maryland 20892.
J Biol Chem. 1988 Mar 15;263(8):3632-8.
Proteoglycans exist in cartilage as complexes in which many proteoglycan molecules are bound to a central filament of hyaluronic acid. Many studies have investigated changes taking place in proteoglycan monomer structure during cartilage catabolism usually under the assumption that hyaluronic acid is a relatively inert metabolic component of the complex. In this paper we present organ culture data supporting a new hypothesis that the catabolism of proteoglycans and hyaluronic acid are coordinately regulated by chondrocytes. The data indicates that: 1) newly synthesized hyaluronate and proteoglycan maintain a nearly constant ratio, almost identical to that existing for the total chemical amounts of these two components in cartilage tissue; 2) these two components are catabolized with virtually identical kinetics; and 3) this catabolic relationship in vitro reflects the loss of hyaluronate and proteoglycans from native, undissociated aggregates as isolated from the tissue. We conclude that hyaluronate catabolism is an integral part of the overall mechanism of proteoglycan resorption in cartilage and that further understanding of this process may be key to the elucidation of the regulatory pathways for proteoglycan resorption in health and disease.
蛋白聚糖在软骨中以复合物的形式存在，其中许多蛋白聚糖分子与一条透明质酸中心细丝结合。许多研究调查了软骨分解代谢过程中蛋白聚糖单体结构的变化，通常假定透明质酸是该复合物中相对惰性的代谢成分。在本文中，我们展示了器官培养数据，支持一种新的假说，即蛋白聚糖和透明质酸的分解代谢由软骨细胞协同调节。数据表明：1）新合成的透明质酸盐和蛋白聚糖维持着几乎恒定的比例，几乎与软骨组织中这两种成分的总化学量的比例相同；2）这两种成分以几乎相同的动力学进行分解代谢；3）体外的这种分解代谢关系反映了从组织中分离出的天然、未解离聚集体中透明质酸盐和蛋白聚糖的损失。我们得出结论，透明质酸盐分解代谢是软骨中蛋白聚糖再吸收整体机制的一个组成部分，对这一过程的进一步理解可能是阐明健康和疾病状态下蛋白聚糖再吸收调节途径的关键。
