Substrate stiffness-dependent gene expression profile for cortical neurons

We undertook mRNA microarray and gene ontology analyses to screen out substrate stiffness-dependent genes. Total mRNA were extracted from E17 cortical neurons grown on soft or stiff substrates at 5 or 16 hr time points. We identified 114 differentially-expressed mRNA transcripts in cells grown on 0.1 kPa and 20 kPa gels at the 5 hr time-point. Among them, 66 were upregulated in 0.1 kPa gel cultures and the remainder were downregulated (compared to cells grown on stiffer substrates). The expressions of three endocytic genes (Cltc, Dab2, and Myo6) and four adhesion genes(Vcl, Robo2, Nrcam, and Cad11) were confirmed by QGP and smRNA FISH. We collected total RNA extracted from E17 cortical neurons on different substrates with various stiffness ( 0.1,1,20 kPa gels and glass). Three independent experiments were performed at two time points (5 hr and 16 hr).