gms | German Medical Science

Background: In healthy normal blood vessels, vSMCs exhibit a contractile, quiescent state, in which cells have increased cytoplasmic myofilaments and are involved in maintaining the vascular tone. However, during a pathogenic vascular remodeling (i.e. after endovascular intervention), vSMCs are triggered to re-enter the cell cycle and transform from a contractile (differentiated) to a synthetic (dedifferentiated) phenotype. The molecular mechanism which control this phenotypic switch are not yet systematically investigated

Materials and methods: An optimized high-throughput RNAi screening platform was developed using time-lapse imaging of live human cells in combination with automated image analysis to identify novel genes that are involved in enhanced proliferation, apoptosis, migration and perturbation of mitosis of HaoSMCs

Results: 257 among 2000 genes tested resulted in a inhibition of cell proliferation in HaoSMCs. After pathway analysis, 38 significant genes were selected to be studied further. 23 genes were confirmed to inhibit proliferation, 13 genes were found to induce apoptosis in the synthetic phenotype. 11 genes led to an aberrant nuclear phenotype indicating a central role in cell mitosis. 4 genes affected the cell migration in synthetic HaoSMCs. Using computational biological network analysis, 11 genes were identified to have an indirect or direct interaction with the osteopontin pathway. For 10 of those genes, protein levels from downstream proteins in the osteopontin pathway were found to be down-regulated by RNAi

Conclusion: We here used a phenotypic high-throughput siRNA screen to identify genes relevant for the cell biology of HaoSMCs. Novel genes were identified which play a role for proliferation, apoptosis mitosis and migration of HaoSMCs. These may represent potential drug candidates in the future