We have successfully designed and fabricated an integrated microfluidic platform, the hESC-microChip, which is capable of reproducible and quantitative culture and analysis of individual hESC colonies in a semi-automated fashion. In this device, a serpentine microchannel allows pre-screening of dissociated hESC clusters, and six individually addressable cell culture chambers enable parallel hESC culture, as well as multiparameter analyses in sequence. In order to quantitatively monitor hESC proliferation and pluripotency status in real time, knock-in hESC lines with EGFP driven by the endogenous OCT4 promoter were constructed. On-chip immunoassays of several pluripotency markers were carried out to confirm that the hESC colonies maintained their pluripotency. For the first time, our studies demonstrated well characterized hESC culture and analysis in a microfluidic setting, as well as a proof-of-concept demonstration of parallel/multiparameter/real-time/automated examination of self-renewal and differentiation in the same device.

SUMMARY Transcription factor activity and turnover are functionally linked, but the global patterns by which DNA-bound regulators are eliminated remain poorly understood. We established an assay to define the chromosomal location of DNA-associated proteins that are slated for degradation by the ubiquitin-proteasome system. The genome-wide map described here ties proteolysis in mammalian cells to active enhancers and to promoters of specific gene families. Nuclear-encoded mitochondrial genes in particular correlate with protein elimination, which positively affects their transcription. We show that the nuclear receptor corepressor NCoR1 is a key target of proteolysis and physically interacts with the transcription factor CREB. Proteasome inhibition stabilizes NCoR1 in a site-specific manner and restrains mitochondrial activity by repressing CREB-sensitive genes. In conclusion, this functional map of nuclear proteolysis links chromatin architecture with local protein stability and identifies proteolytic derepression as highly dynamic in regulating the transcription of genes involved in energy metabolism.

Vascular smooth muscle cells (VSMCs) play a major role in the pathophysiology of cardiovascular diseases. The advent of induced pluripotent stem cell (iPSC) technology and their capability to differentiation into virtually every cell type in the human body make this field a ray of hope for vascular regenerative therapy and for understanding disease mechanism. In this review, we first discuss the recent iPSC technology and vascular smooth muscle development from embryo and then examine different methodology to derive VSMCs from iPSCs and their applications in regenerative therapy and disease modeling.