Collagen modulates cell shape and cytoskeleton of embryonic corneal and fibroma fibroblasts: Distribution of actin, α-actinin, and myosin☆

[摘要] Intheembryo,fibroblastsmigratingthroughextracellularmatrices(ECM)aregenerallyelongateinshape,exhibitingaleadingpseudopodiumwithfilopodialextensions,andatrailingcellprocess.LittleisknownaboutthemechanismofmovementofembryoniccellsinECM,forstudiesoffibroblastlocomotioninthepasthavebeenlargelyconfinedtoobservationsofflattenedcellsgrownonplanarsubstrata.Weconfirmherethatembryonicaviancornealfibroblastsmigratingwithinhydratedcollagengelsinvitrohavethebipolarmorphologyoffibroblastsinvivo,andweshowforthefirsttimethathighlyflattenedgerbilfibromafibroblasts,grownascelllinesonplanarsubstrata,canalsorespondtohydratedcollagengelsbybecomingelongateinshape.Wedemonstratethatthecollagen-mediatedchangeincellshapeisaccompaniedbydramaticrearrangementoftheactin,α-actinin,andmyosincomponentsofthecytoskeleton.Byimmunofluorescence,thestressfibersoftheflattenedcornealfibroblastsgrownonglassareseentostainwithantiactin,anti-α-actinin,andantimyosin,ashasbeenreportedforfibromaandotherfibroblastsgrownonglass.Stressfibers,adhesionplaques,andrufflesdonotdevelopwhenthecornealorfibromafibroblastisgrowninECM;thesefeaturesseemtobearesponsetostrongattachmentofthecellundersidetoaplanarsubstratum.WhenthefibroblastsaregrowninECM,antimyosinstainingisdistributeddiffuselythroughthecytoplasm.Antiactinandanti-α-actininstainthemicrofilamentouscellcortexstrongly.WesuggestthatlocomotionofthefibroblastinECMisaccompaniedbyadhesionofthecelltothecollagenfibrilsandmayinvolveaninteractionofthemyosin-richcytosolwiththeactin-richfilamentouscellcortex.Interestingly,thenumerousfilopodiathatcharacterizethetipsofmotilepseudopodiaofcellsinECMareveryrichinactinandα-actinin,butseemtolackmyosin;iffilopodiausemyosintomove,theinteractionmustbeatadistance.Solublecollagendoesnotconvertflattenedfibroblastsonplanarsubstratatobipolarcells.Thus,theeffectofcollagenonthefibroblastcytoskeletonseemstodependonthepresenceofcollagenfibrilsinagelsurroundingthecell.

[学科分类] 生物科学（综合）