Secretion of proteoglycans by chondrocytes. Influence of colchicine, cytochalasin B, and β-d-xyloside

Forskningsoutput: TidskriftsbidragArtikel i vetenskaplig tidskrift

Abstract

Chondrocytes obtained from epiphyseal cartilage of fetal guinea pigs or ear cartilage of young rabbits were cultured in monolayer. The influence of colchicine, cytochalasin B, and p-nitrophenyl-β-d-xylopyranoside on secretion of proteoglycans was investigated. Radioactive sulfate was used as a precursor. As observed previously in other systems, β-d-xylosides initiated the synthesis of free chondroitin sulfate chains, competing with the endogenous proteoglycan core protein acceptor. The molecular weights of the chondroitin sulfate chains synthesized both on the xyloside and on the core-protein acceptor in maximally stimulated cells were similar and significantly lower than in proteoglycans synthesized in the absence of xyloside. The size of the chondroitin sulfate chains synthesized on the xyloside was inversely related to the concentration of this compound. This finding suggests that the chain length is dependent on the ratio between available acceptor and chain-lengthening enzymes or precursors. Cytochalasin B, a microfilament-modifying agent, inhibited proteoglycan synthesis, without any effect on secretion. Cells treated with cytochalasin B could be stimulated with β-d-xyloside to synthesize free chondroitin sulfate chains to the same relative degree as cells with intact microfilaments. Colchicine, an antimicrotubular agent, partially inhibited synthesis and secretion of proteoglycan. However, cells treated with colchicine could be stimulated with β-d-xyloside to synthesize and secrete free chondroitin sulfate chains to about the same relative degree as cells with intact microtubules. The data suggest that microtubules may have a facilitatory rather than an obligatory role in the secretion of proteoglycans and that at least part of the effect of colchicine is located at or after the site of glycosaminoglycan synthesis.

Detaljer

Författare
Enheter & grupper
Externa organisationer
  • Karolinska Institute
Forskningsområden

Ämnesklassifikation (UKÄ) – OBLIGATORISK

  • Ortopedi
Originalspråkengelska
Sidor (från-till)148-157
Antal sidor10
TidskriftArchives of Biochemistry and Biophysics
Volym192
Utgåva nummer1
StatusPublished - 1979
PublikationskategoriForskning
Peer review utfördJa