Complex multicomponent patterns rendered on a 3D DNA-barrel pegboard.

DNA origami, in which a long scaffold strand is assembled with a many short staple strands into parallel arrays of double helices, has proven a powerful method for custom nanofabrication. However, currently the design and optimization of custom 3D DNA-origami shapes is a barrier to rapid application to new areas. Here we introduce a modular barrel architecture, and demonstrate hierarchical assembly of a 100 megadalton DNA-origami barrel of ~90 nm diameter and ~250 nm height, that provides a rhombic-lattice canvas of a thousand pixels each, with pitch of ~8 nm, on its inner and outer surfaces. Complex patterns rendered on these surfaces were resolved using up to twelve rounds of Exchange-PAINT super-resolution microscopy. We envision these structures as versatile nanoscale pegboards for applications requiring complex 3D arrangements of matter, which will serve to promote rapid uptake of this technology in diverse fields beyond specialist groups working in DNA nanotechnology.

Alginate and DNA Gels Are Suitable Delivery Systems for Diabetic Wound Healing.

Diabetic foot ulcers (DFU) represent a severe health problem and an unmet clinical challenge. In this study, we tested the efficacy of novel biomaterials in improving wound healing in mouse models of diabetes mellitus (DM). The biomaterials are composed of alginate- and deoxyribonucleic acid (DNA)-based gels that allow incorporation of effector cells, such as outgrowth endothelial cells (OEC), and provide sustained release of bioactive factors, such as neuropeptides and growth factors, which have been previously validated in experimental models of DM wound healing or hind limb ischemia. We tested these biomaterials in mice and demonstrate that they are biocompatible and can be injected into the wound margins without major adverse effects. In addition, we show that the combination of OEC and the neuropeptide Substance P has a better healing outcome than the delivery of OEC alone, while subtherapeutic doses of vascular endothelial growth factor (VEGF) are required for the transplanted cells to exert their beneficial effects in wound healing. In summary, alginate and DNA scaffolds could serve as potential delivery systems for the next-generation DFU therapies.

Src modulates contractile vascular smooth muscle function via regulation of focal adhesions.

Src is a known regulator of focal adhesion turnover in migrating cells; but, in contrast, Src is generally assumed to play little role in differentiated, contractile vascular smooth muscle (dVSM). The goal of the present study was to determine if Src-family kinases regulate focal adhesion proteins and how this might affect contractility of non-proliferative vascular smooth muscle. We demonstrate here, through the use of phosphotyrosine screening, deconvolution microscopy imaging, and differential centrifugation, that the activity of Src family kinases in aorta is regulated by the alpha agonist and vasoconstrictor phenylephrine, and leads to focal adhesion protein phosphorylation and remodeling in dVSM. Furthermore, Src inhibition via morpholino knockdown of Src or by the small molecule inhibitor PP2 prevents phenylephrine-induced adhesion protein phosphorylation, markedly slows the tissue's ability to contract, and decreases steady state contractile force amplitude. Significant vasoconstrictor-induced and Src-dependent phosphorylation of Cas pY-165, FAK pY-925, paxillin pY-118, and Erk1/2 were observed. However, increases in FAK 397 phosphorylation were not seen, demonstrating differences between cells in tissue versus migrating, proliferating cells. We show here that Src, in a cause and effect manner, regulates focal adhesion protein function and, consequently, modulates contractility during the action of a vasoconstrictor. These data point to the possibility that vascular focal adhesion proteins may be useful drug discovery targets for novel therapeutic approaches to cardiovascular disease.