1984•Unpublished venueRequires access
Inductionof Chondrogenesis inLimb Mesenchymal Cultures by Disruptionofthe ActinCytoskeleton
Michael Solursh, Universityof Iowa
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Abstract
�Cellshape isknown to influencethe chondrogenic differentiation ofculturedlimb bud mesenchyme cells(Solursh,M .,T.F.Linsenmayer,and K.L.Jensen,1982,Dev .Biol.,94: 259-264) .To testwhether specificcytoskeletalcomponents mediate thisinfluenceof cell shape, we examined differentcytoskeletondisruptingagentsfortheirabilityto affectchondrogenesis.Limb bud cellsculturedat subconfluentdensitieson plasticsubstratanormally become flattened,containnumerous cytoplasmicmicrotubulesand actinbundles,and do not undergo spontaneous chondrogenesis.Ifsuch culturesaretreatedwith 2 /Ag/mlcytochalasin D duringthe initial 3-24 h inculture,thecellsround up, losetheiractincables,and undergo chondrogenesis,asindicatedby theproductionofimmunologicallydetectabletype IIcollagen and a pericellular Alcianblue stainingmatrix.CytochalasinD alsoinduces cartilageformation by high-densityculturesof proximal limb bud cells,which normally become blocked ina protodifferentiated state.Inaddition,cytochalasinD was found toreversethenormal inhibition by fibronectinofchondrogenesis by proximal limb bud cellsculturedin hydrated Collagen gels.Agents thatdisruptmicrotubuleshave no apparent effecton the shape orchondrogenic differentiation of limb bud mesenchymal cells.These resultssuggestan involvement of the actincytoskeletonin controllingcellshape and chondrogenic differentiation of limb bud mesenchyme .Interactionsoftheactincytoskeletonand extracellular matrixcomponents may providea regulatorymechanism formesenchyme celldifferentiation intocartilageor fibrous connectivetissueinthedeveloping limb.