Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0851184 (thinning)
 11,252 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Fibroblasts were cultured on top of or at the bottom of hydrated collagen lattices. Shortly after initially interacting with the collagen lattices, fibroblasts appeared to attach to individual collagen fibrils and in many cases cell processes were found wrapped around clusters of collagen fibrils. Tension generated by cells during spreading resulted in proximal collagen fibrils becoming aligned distal in the plane of spreading and more densely packed. During subsequent culture, the collagen fibrils to the cells underwent a similar reorganization and the lattice thinned to one-tenth of its original thickness. The rate of thinning was similar regardless of whether the cells were originally above or at the bottom of the lattices. The presence of cells distributed throughout the lattice was unnecessary for lattice reorganization to occur. When the lattices were allowed to come off the underlying substratum, compaction of the collagen gels was observed, and the resulting matrix had the typical appearance of dermis as observed by both light and electron microscopy. Collagen fibrils associated with the cell surface often appeared to be under tension and, in regions of close fibril binding, there was a prominent reorganization of submembranous microfilaments. It is suggested that reorganization of the collagen lattice by fibroblasts may depend upon secreted cell factors as well as physical forces generated by the cells.
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PMID:Reorganization of hydrated collagen lattices by human skin fibroblasts. 654 Feb 73

Membrane tension modulates cellular processes by initiating changes in the dynamics of its molecular constituents. To quantify the precise relationship between tension, structural properties of the membrane, and the dynamics of lipids and a lipophilic reporter dye, we performed atomistic molecular dynamics (MD) simulations of DiI-labeled dipalmitoylphosphatidylcholine (DPPC) lipid bilayers under physiological lateral tensions ranging from -2.6 mN m(-1) to 15.9 mN m(-1). Simulations showed that the bilayer thickness decreased linearly with tension consistent with volume-incompressibility, and this thinning was facilitated by a significant increase in acyl chain interdigitation at the bilayer midplane and spreading of the acyl chains. Tension caused a significant drop in the bilayer's peak electrostatic potential, which correlated with the strong reordering of water and lipid dipoles. For the low tension regime, the DPPC lateral diffusion coefficient increased with increasing tension in accordance with free-area theory. For larger tensions, free area theory broke down due to tension-induced changes in molecular shape and friction. Simulated DiI rotational and lateral diffusion coefficients were lower than those of DPPC but increased with tension in a manner similar to DPPC. Direct correlation of membrane order and viscosity near the DiI chromophore, which was just under the DPPC headgroup, indicated that measured DiI fluorescence lifetime, which is reported to decrease with decreasing lipid order, is likely to be a good reporter of tension-induced decreases in lipid headgroup viscosity. Together, these results offer new molecular-level insights into membrane tension-related mechanotransduction and into the utility of DiI in characterizing tension-induced changes in lipid packing.
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PMID:Atomistic simulation of lipid and DiI dynamics in membrane bilayers under tension. 2115 16