system
Medical AI Inquiry: You was designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.  Labels: OBJECTIVE, RESULTS. Meshes: Alleles, Animals, Aorta, Cell Division, Cell Movement, Cells, Cultured, Collagen Type I, Collagen Type VIII, Extracellular Matrix, Matrix Metalloproteinase 2, Matrix Metalloproteinase 9, Mice, Mice, Knockout, Microscopy, Video, Muscle, Smooth, Vascular, Up-Regulation.
user
Are migration and growth attenuated in vascular smooth muscle cells with type VIII collagen-null alleles? Context: Type VIII collagen is upregulated after vascular injury and in atherosclerosis. However, the role of type VIII collagen endogenously expressed by smooth muscle cells (SMCs) and in the context of the vascular matrix microenvironment, which is rich in type I collagen, is not known. To address this, we have compared aortic SMCs from wild-type (WT) mice to SMCs from type VIII collagen-deficient (KO) mice when plated on type I collagen. Type VIII collagen was upregulated after wounding of WT SMCs. KO SMCs exhibited greater adhesion to type I collagen than WT SMCs (optical density [OD595]=0.458+/-0.044 versus 0.193+/-0.071). By contrast, the WT SMCs spread more (389+/-75% versus 108+/-14% increase in cell area), migrated further (total distance 80.6+/-6.2 microm versus 64.2+/-4.4 microm), and exhibited increased [3H]-thymidine uptake (160,000+/-22,300 versus 63,100+/-12,100 counts per minute) when compared with KO SMCs. Gelatin zymograms showed that WT SMCs expressed latent matrix metalloproteinase 2, whereas KO SMCs did not. Addition of exogenous type VIII collagen returned levels of KO SMC adhesion (OD595=0.316+/-0.038), migration (79.5+/-5.8 microm), and latent matrix metalloproteinase 2 expression to levels comparable to WT SMCs.
assistant
This study suggests that SMCs can modify the matrix microenvironment by producing type VIII collagen, using it to overlay type I collagen, and generating a substrate favorable for migration. Final Decision: yes