Type I collagen gels for assessing the combined effects of ligand concentration-dependent elasticity and fibril density on cells

Type I collagen (Col-I) is the most abundant fibrous protein in the extracellular matrix (ECM); its densification is involved in conditions including cancer, fibrosis, vascular diseases, and aging. Increased Col-I concentrations lead to increased ECM fibril density and stiffening; therefore, the effects of such changes in the microenvironment of cells require examination. Three types of Col-I gels were developed by introducing reagent-free radiation-induced crosslinking, while adjusting the distance between the Col-I monomers or fibrils. The adhesion area of HeLa human cervical cancer epithelial cells, human induced pluripotent stem (hiPS) cells, and 3T3-Swiss albino mouse embryonic fibroblasts, tended to decrease with increasing fibril density when the ligand concentration-dependent elasticity (C-E) was constant. In the absence of fibrils, the adhesion area of HeLa and 3T3-swiss cells increased with increasing C-E, whereas hiPS cells clustered regardless of C-E. When C-E and the fibril density increased simultaneously, the adhesion area of HeLa and 3T3-swiss cells remained unchanged due to the two opposing effects. Our results highlight the importance of evaluating the combined effects of the compositional, mechanical, and topographical cues of Col-I on cells. The developed Col-I gels will contribute to elucidating the role of Col-I in development, differentiation, regeneration, disease, and aging. HighlightsO_LICol-I concentration-dependent elasticity (C-E) and fibril density were separated. C_LIO_LIAdhesion areas of cells decreased with increasing fibril density at constant C-E. C_LIO_LIAdhesion areas of cells increased with increasing C-E in absence of Col-I fibrils. C_LIO_LIAdhesion areas remained unchanged when both C-E and fibril density increased. C_LIO_LIStructural, mechanical and topographical cues work in combination to affect cells. C_LI Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=78 SRC="FIGDIR/small/642521v1_ufig1.gif" ALT="Figure 1"> View larger version (34K): org.highwire.dtl.DTLVardef@11b5779org.highwire.dtl.DTLVardef@bd1b5org.highwire.dtl.DTLVardef@1f4cf6eorg.highwire.dtl.DTLVardef@15e7f5c_HPS_FORMAT_FIGEXP M_FIG C_FIG