The Elasticity Effects On The Integrin/Ligand Interaction Studied By Atomic Force Microscope

The cell elastic property is one important parameter on the cell biomechanicsresearch, the structure and physiological functions of cells are closely related with thegrowth environment of cell, and the physical changing of microenvironment of cell cannot only cause the cell elasticity changed but also the expression of integrin and outsideof the cell orientation. They can affect the interactions between integrin and theirligands.The chitosan/polyacrylamide hydrogel is a variable substrate material, and HepG2cells are planted on different rigidity of chitosan/polyacrylamide hydrogen substrates.After48hours, morphological characteristics of HepG2cell (such as spread area,long/short axis ratio) are measured, and the cytoskeleton is observed by FITC-phalloidin, then the expression of integrinα6β1is detected using FCM; the surfacetopography; cell elasticity of HepG2in different rigidity substrate and the interactionsbetween integrinα6β1and LN under physiological conditions are detected by AFM. Themain results obtained in this study as follows:(1) The rigidity of chitosan/polyacrylamide hydrogel is adjustable, and can be used as base material for cellmechanics research.(2) The greater basal rigidity, the more spread area and long/shortaxis ratio of HepG2cell.(3) The surface topography and cell elasticity of HepG2cellare discrepant in different rigidity. The less pseudopodia extending from cell edge in thehardness of substrate of1000Pa, the more pseudopodia in the control group. TheYoung’s modulus of HepG2cells in the control group,3500Pa and1000Pa rigiditysubstrate are2036+1045Pa,714+311Pa and803+445Pa.(4) The adhesion proportion ofcell is different in each rigidity, the interaction force between integrinα6β1and ligand(LN) are19±7pN、37.5±15.8pN and38.85±19.7pN.(5) The cytoskeleton colorationsdetected that the cytoskeleton of HepG2is clear and throughout the cell in control group,while it is not obvious and distributes in the edge of cells in experimental group.(6) Theexpression of integrin on cell surface in different rigidity: the integrinα6β1increaseswhen substrate becomes softer (P<0.05).