Keratan sulfate

About: Keratan sulfate is a research topic. Over the lifetime, 1253 publications have been published within this topic receiving 57984 citations. The topic is also known as: keratan sulfate & KS.

Biochemical analyses of proteoglycans in rabbit corneal scars.

Abstract: Macromolecules from normal rabbit cornea and cornea containing a 2-mm diameter button of scar tissue were biosynthetically labeled with 35S-sulfate and 3H-glucosamine in vivo and in organ culture. Labeled macromolecules, including proteoglycans (PGs) extracted from the normal cornea, scar tissue, and corneal tissue adjacent to the scar with guanidine hydrochloride were chromatographed on DEAE-Sepharose CL-6B columns and eluted with increasing concentrations of NaCl. The elution pattern of corneal macromolecules synthesized in vitro was remarkably similar to that in vivo. In another experiment, corneas having 2-, 4-, and 8-week-old scars were labeled in organ culture and also extracted. Scars synthesized PGs with lower sulfation than those of adjacent corneal tissue. Although PG synthesis in scar decreased with wound age, the synthesis in adjacent cornea remained the same. In a third experiment, PGs extracted from pools of unlabeled 2- and 4-week-old scars, adjacent corneal tissue, and normal corneas were chromatographed on ion-exchange columns and analyzed chemically. The quantity of PGs in scar and adjacent cornea increased with healing time. The ratios of keratan sulfate PG to dermatan sulfate PG in normal cornea, scar, and adjacent cornea was 2.3, 0.6, and 1.5, respectively. The PGs from adjacent corneal tissue had a higher charge density than those from scar. The predominant adjacent-cornea dermatan sulfate PG had a higher charge density than that in normal cornea. The authors conclude that cornea adjacent to the healing wound synthesized PGs measurably different fro those in scar and normal cornea.

Sulfated glycosaminoglycans: their distinct roles in stem cell biology

Abstract: Sulfated glycosaminoglycan (GAG) chains are a class of long linear polysaccharides that are covalently attached to multiple core proteins to form proteoglycans (PGs). PGs are major pericellular and extracellular matrix components that surround virtually all mammalian cell surfaces, and create conducive microenvironments for a number of essential cellular events, such as cell adhesion, cell proliferation, differentiation, and cell fate decisions. The multifunctional properties of PGs are mostly mediated by their respective GAG moieties, including chondroitin sulfate (CS), heparan sulfate (HS), and keratan sulfate (KS) chains. Structural divergence of GAG chains is enzymatically generated and strictly regulated by the corresponding biosynthetic machineries, and is the major driving force for PG functions. Recent studies have revealed indispensable roles of GAG chains in stem cell biology and technology. In this review, we summarize the current understanding of GAG chain-mediated stem cell niches, focusing primarily on structural characteristics of GAG chains and their distinct regulatory functions in stem cell maintenance and fate decisions.

Extracellular matrix adhesion-promoting activities of a dermatan sulfate proteoglycan-associated protein (22K) from bovine fetal skin.

Abstract: A 22 x 10(3) Mr protein (abbreviated 22K) that copurifies with dermatan sulfate proteoglycans (DS-PGs) following the biochemical fractionation of bovine fetal skin has been evaluated for adhesion-promoting activity in vitro using Balb/c 3T3 cells, as well as bovine and human dermal fibroblasts. Substrata coated with 22K protein promote attachment of a subset of 3T3 and dermal fibroblasts that respond to plasma fibronectin (pFN) substrata. Cells on 22K protein display partial cytoplasmic spreading, comparable to that of cells adhering to cell-binding fragments of pFN. Adhesion activity of 22K is not due to contamination with known adhesive proteins of dermal matrices and is not dermal cell type-specific, since two classes of neuronal cells also respond effectively to 22K substrata. DS-PGs from cartilage or skin completely inhibit 22K adhesion activity when the PGs are adsorbed to 22K substrata under conditions prohibiting PGs from binding to substrata directly. Cartilage chondroitin/keratan sulfate proteoglycan at much higher concentrations is only partially inhibitory. Inhibition by DS-PGs is mediated by DS chains binding to 22K. Properties of the cell surface 'receptor' for 22K protein were tested by several approaches. It is not cell surface DS-PG, since: (1) cells unable to produce this proteoglycan class also responded; (2) cells treated with chondroitinase ABC responded equally well; and (3) substrata of proteoglycan-binding platelet factor-4 generated responses from cells that were quantitatively and qualitatively different. A synthetic peptide in the medium containing the Arg-Gly-Asp-Ser (RGDS) sequence completely inhibited responses to 22K substrata. This observation, coupled with sequencing data of 22K protein revealing an Arg-Gly-Ala-Thr sequence at residues 151-154, suggest that 22K protein mediates adhesion by cell surface integrin binding. Therefore, this newly discovered matrix protein from skin may serve as a communication link between the dermal fibroblast cell surface and its extracellular matrix environment.