Directing and Potentiating Stem Cell-Mediated Angiogenesis and Tissue Repair by Cell Surface E-Selectin Coating.

Stem cell therapy has emerged as a promising approach for treatment of a number of diseases, including delayed and non-healing wounds. However, targeted systemic delivery of therapeutic cells to the dysfunctional tissues remains one formidable challenge. Herein, we present a targeted nanocarrier-mediated cell delivery method by coating the surface of the cell to be delivered with dendrimer nanocarriers modified with adhesion molecules. Infused nanocarrier-coated cells reach to destination via recognition and association with the counterpart adhesion molecules highly or selectively expressed on the activated endothelium in diseased tissues. Once anchored on the activated endothelium, nanocarriers-coated transporting cells undergo transendothelial migration, extravasation and homing to the targeted tissues to execute their therapeutic role. We now demonstrate feasibility, efficacy and safety of our targeted nanocarrier for delivery of bone marrow cells (BMC) to cutaneous wound tissues and grafted corneas and its advantages over conventional BMC transplantation in mouse models for wound healing and neovascularization. This versatile platform is suited for targeted systemic delivery of virtually any type of therapeutic cell.

Design and development of high bioluminescent resonance energy transfer efficiency hybrid-imaging constructs.

Here we describe the design and construction of an imaging construct with high bioluminescent resonance energy transfer (BRET) efficiency that is composed of multiple quantum dots (QDs; λem = 655 nm) self-assembled onto a bioluminescent protein, Renilla luciferase (Rluc). This is facilitated by the streptavidin-biotin interaction, allowing the facile formation of a hybrid-imaging construct (HIC) comprising up to six QDs (acceptor) grafted onto a light-emitting Rluc (donor) core. The resulting assembly of multiple acceptors surrounding a donor permits this construct to exhibit high resonance energy transfer efficiency (∼64.8%). The HIC was characterized using fluorescence excitation anisotropy measurements and high-resolution transmission electron microscopy. To demonstrate the application of our construct, a generation-5 (G5) polyamidoamine dendrimer (PAMAM) nanocarrier was loaded with our HIC for in vitro and in vivo imaging. We envision that this design of multiple acceptors and bioluminescent donor will lead to the development of new BRET-based systems useful in sensing, imaging, and other bioanalytical applications.

A targeted and adjuvanted nanocarrier lowers the effective dose of liposomal amphotericin B and enhances adaptive immunity in murine cutaneous leishmaniasis.

BACKGROUND: Amphotericin B (AmB), the most effective drug against leishmaniasis, has serious toxicity. As Leishmania species are obligate intracellular parasites of antigen presenting cells (APC), an immunopotentiating APC-specific AmB nanocarrier would be ideally suited to reduce the drug dosage and regimen requirements in leishmaniasis treatment. Here, we report a nanocarrier that results in effective treatment shortening of cutaneous leishmaniasis in a mouse model, while also enhancing L. major specific T-cell immune responses in the infected host. METHODS: We used a Pan-DR-binding epitope (PADRE)-derivatized-dendrimer (PDD), complexed with liposomal amphotericin B (LAmB) in an L. major mouse model and analyzed the therapeutic efficacy of low-dose PDD/LAmB vs full dose LAmB. RESULTS: PDD was shown to escort LAmB to APCs in vivo, enhanced the drug efficacy by 83% and drug APC targeting by 10-fold and significantly reduced parasite burden and toxicity. Fortuitously, the PDD immunopotentiating effect significantly enhanced parasite-specific T-cell responses in immunocompetent infected mice. CONCLUSIONS: PDD reduced the effective dose and toxicity of LAmB and resulted in elicitation of strong parasite specific T-cell responses. A reduced effective therapeutic dose was achieved by selective LAmB delivery to APC, bypassing bystander cells, reducing toxicity and inducing antiparasite immunity.