A selective microRNA-based strategy inhibits restenosis while preserving endothelial function.

Drugs currently approved to coat stents used in percutaneous coronary interventions do not discriminate between proliferating vascular smooth muscle cells (VSMCs) and endothelial cells (ECs). This lack of discrimination delays reendothelialization and vascular healing, increasing the risk of late thrombosis following angioplasty. We developed a microRNA-based (miRNA-based) approach to inhibit proliferative VSMCs, thus preventing restenosis, while selectively promoting reendothelialization and preserving EC function.

Adhesion strength-based, label-free isolation of human pluripotent stem cells.

We demonstrate substantial differences in 'adhesive signature' between human pluripotent stem cells (hPSCs), partially reprogrammed cells, somatic cells and hPSC-derived differentiated progeny. We exploited these differential adhesion strengths to rapidly (over ∼10 min) and efficiently isolate fully reprogrammed induced hPSCs (hiPSCs) as intact colonies from heterogeneous reprogramming cultures and from differentiated progeny using microfluidics. hiPSCs were isolated label free, enriched to 95%-99% purity with >80% survival, and had normal transcriptional profiles, differentiation potential and karyotypes.

Quantitative analysis of retroviral and lentiviral gene transfer to murine embryonic stem cells.

The effectiveness of retrovirus or lentivirus transduction of embryonic stem (ES) cells is often limited because transgene expression is silenced or variegated. We wondered if other steps of transduction, in addition to gene expression, were restricted in ES cells. We quantitatively compared (1) the amount of virus binding, (2) the number of integrated transgenes, and (3) the resulting level of gene expression.

Complexation of retroviruses with polymers significantly increases the number of genes transferred to murine embryonic stem cells, but does not raise transgene expression levels.

Embryonic stem cells efficiently silence retrovirus transgene expression. To help to solve this problem, retroviruses have been developed that are more resistant to silencing, such as retroviruses derived from the MSCV (murine-stem-cell virus). A complementary approach to increasing transgene expression might be to increase the number of integrated transgenes.