9 nots - 1 October 6, 2008 Chondrogenesis, HA and aggrecan...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
1 October 6, 2008 Lecture 9 Chondrogenesis, HA and aggrecan Read pages 1091-1096 Albert 4th edition, Remember from the last lecture that HA is a non-sulfated GAG. Proteoglycans (PGs) are composed of GAG chains consisting of repeated disaccharides, which usually contain a sulfated hexosamine and uronic acid, covalently linked to a central protein core. Distinct classes of GAGs are recognized based on different monosaccharide composition, sulfation, and epimerization of uronic acid. See slides 25-30, lecture 8 and Alberts for details. Hybrid molecules with additional structural diversity may arise due to the attachment of N- and O-linked glycoprotein-type oligosaccharides. You are responsible for remembering the names of sugar repeats that make up the major GAGs, not their precise chemical composition. Chondrogenesis It has long been known that in cartilage, the ECM exerts effects on chondrocyte cells shape, phenotype, and metabolism. Conversely, chondrocyte cell shape changes exert effects on matrix organization, assembly, and retention. The process of dynamic reciprocity we discussed at the beginning of the course. Structure of the growth plate (Verbatim with minor modifications from S. Price, B.O. Oyajobi and R.G.G. Russell Department of Human Metabolism and Clinical Biochemistry, Sheffield University Medical School, Beech Hill Road, Sheffield S10 1RX, UK, http://www.unu.edu/Unupress/food2/UID06E/uid06e0u.htm ,references removed) The epiphyseal growth plate is made up of three tissue types: the cartilage component divided into distinct zones (slides 5) , the bony tissue of the metaphysis and the fibrous tissue that surrounds the growth plate. The vascular supplies to the growth plate are not illustrated in slide 5, but remember that the primary and secondary ossification regions are highly vascularized. Growth plate chondrocytes are organized into different zones (slides 5 and 6) with each cell population being part of a different stage of maturation in the endochondral sequence. Traditionally studies of growth plate have described cell populations in terms of cell size, shape and contents. Functions of these cells used to be speculated upon depending on their morphology. However, improvements in cell and molecular biology techniques now enable growth plate chondrocyte function to be studied where morphology is maintained. Reserve or resting zone . Cells exist singly or in pairs separated by an abundant extracellular matrix, and have low rates of proliferation. Proteoglycan synthesis and type
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
2 II collagen synthesis is low. However, these cells have a high lipid body and vacuole content that has led to the suggestion that this zone is involved with storage for later nutritional requirements. Proliferative cartilage cells or columnar zone
Background image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 6

9 nots - 1 October 6, 2008 Chondrogenesis, HA and aggrecan...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online