The structure and degradation of aggrecan in human intervertebral disc.

The ability of the intervertebral disc to resist compression is dependent on its high proteoglycan concentration. The disc proteoglycans are classified as aggregating or non-aggregating depending on their ability to interact with hyaluronan. The majority of the aggregating proteoglycans are derived from aggrecan, though their glycosaminoglycan substitution pattern has not been determined.

Cleavage of fibromodulin in cartilage explants involves removal of the N-terminal tyrosine sulfate-rich region by proteolysis at a site that is sensitive to matrix metalloproteinase-13.

Integrity of cartilage fails in joint disease. The current work aimed to identify candidate active proteinases in joint diseases using an in vitro model for cartilage degradation induced by interleukin-1. A critical event in the process of cartilage destruction in joint disease is the failure of the collagen fiber network to maintain integrity.

Identification of tyrosine sulfation in extracellular leucine-rich repeat proteins using mass spectrometry.

Multiple and variable tyrosine sulfation in extracellular class II leucine-rich repeat proteins/proteoglycans were characterized by mass spectrometry. The sulfogroup on tyrosine is labile and is released from peptides under normal mass spectrometric conditions. Thus, special approaches must be considered in order to identify this modification.

The human lumbar endplate. Evidence of changes in biosynthesis and denaturation of the extracellular matrix with growth, maturation, aging, and degeneration.

Study Design: The authors measured concentrations of specific molecules reflecting matrix synthesis and degradation in 121 human endplates and correlated them with aging and grade of degeneration.

Objectives: Abnormal endplate development has been implicated in many spinal abnormalities, yet little is known about endplate matrix component turnover.

Summary Of Background Data: Techniques are available to perform an in situ investigation of matrix component turnover with aging and degeneration.

Enhanced denaturation of the alpha (II) chains of type-II collagen in normal adult human intervertebral discs compared with femoral articular cartilage.

The mechanical strength of connective tissues is dependent on the integrity of their fibrillar collagen frameworks. The objective of the present study was to assess type-II collagen damage (denaturation) in the adult human intervertebral disc compared with articular cartilage, in order to determine whether damage to this molecule may vary in different anatomical sites in the same person. A new immunochemical assay was used to measure the amounts of denatured and total type-II collagen in the annulus fibrosus and nucleus pulposus of the L5-S1 disc and in cartilage from the femoral condyles of the same individuals (n = 7).