Illustration of this novel targeted systemic cell delivery system.

<p>The cell surface is coated with nanocarriers composed of dendrimers conjugated with adhesion molecules. These nanocarriers guide coated cells homing to the desired tissue via association with the counterpart molecules highly or selectively expressed on the endothelium of diseased tissues.</p

Local and systemic delivery of Ac-G5-sE-sel nanocarrier coated MSC to murine wound tissues.

<p><b>A</b>: Pro-angiogenic effect of locally injected Ac-G5-sE-sel nanocarrier coated MSC to wounded db/db mice. 1 x 10⁶ of MSC from donor db/db were coated with Ac-G5-sE-sel or Ac-G5-BSA nanocarriers, and directly injected into wound bed of wounded db/db mice. (<i>top</i>) Representative images of confocal microscopy of Dil perfusion; (<i>bottom</i>) quantitative data of Dil-stained blood vessel density in wound (n = 6 mice/group). <b>B</b>: Homing of systemically delivered Ac-G5-sE-sel nanocarrier coated MSC to wound tissues. 1 x 10⁶ of MSC (LacZ⁺/Luc2⁺) from donor mice were coated with Ac-G5-sE-sel or Ac-G5-BSA nanocarriers, and systemically infused into wounded C57BL/6 mice. (<i>top</i>) Representative images of β-gal and CD31 staining (brown) of wound and normal skin tissues. IHC was performed on harvested wounds at day 8 post cell administration in frozen samples that were also subjected to β-gal (blue) staining. Normal skin tissues were used as negative control. (<i>bottom</i>) Quantitative data of β-gal⁺, CD31⁺ (single positive) and β-gal⁺/CD31⁺ (double positive) cells (X10). Numbers of positive cells were counted from 5 randomly selected fields in wound and skin samples. Data are percentage of mean ± SD (n = 6 mice/group). <b>C</b>. Pro-healing effect of systemic delivery of Ac-G5-sE-sel coated MSC. Healing rate expressed as percent of wound re-epithelialization (covered with new skin). <i>Top</i>: representative wounds at different days are shown for each group. <i>Bottom</i>: wound healing rate. Data are percentage of mean ± SD (n = 6 mice/group).</p

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

<div><p>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.</p></div

Increased expression of E-selectin ligand, CD44, in luminal EC of skin wounds compared to normal skin.

<p>A. Co-expression (yellow) of CD44 (green) and KDR (red) in vessels was detected by immunostaining. Representative images were showed (n = 6 mice/group). The lower panels are enlarged highlighted areas in the upper panels. B. Quantification of CD44 expression in vessels. Data are presented as mean ± SD of KDR (red fluorescence intensity), CD44 (green fluorescence intensity) and ratio of CD44: KDR signals from 5 random selected sections of low power field (LPF, X 10).</p

Increased recruitment of systemically infused Ac-G5-sE-sel nanocarrier-coated BMC into grafted corneas enhances neovascularization.

<p><i>Top</i>: increased recruitment of Ac-G5-sE-sel coated EGFP⁺ BMC to the grafted cornea compared to cells coated with control nanocarrier. <b>A & B.</b> Representative images. The enlarged box is an area along the surgical incision that shows the enhanced recruited cells coated with Ac-G5-sE-sel. <b>C.</b> Quantitative intensity of the recruited EGFP⁺ BMC (mean ± SD). <i>Bottom</i>: Enhanced corneal neovascularization. Blood vessel density was measured by DiI perfusion and confocal microscopy. <b>D, E, F.</b> Representative images of neovascularization 2-days post injection of BMC either uncoated or coated with Ac-G5-sE-sel nanocarrier, respectively (OD (oculus dexter (the right eye))-sutured cornea; OS (oculus sinister (the left eye))-non-sutured eye). <b>G.</b> Fluorescent intensity of new-vessels in two groups mean ± SD, n = 5 mice/group.</p

Targeted systemic delivery of nanocarrier-coated MSC to wound tissues.

<p><b>A</b>. <i>In vivo</i> IVIS imaging shows an increased Ac-G5-dendrimer-sE-sel nanocarrier-coated Luc2⁺-MSC homed to wound tissues compared to either uncoated Luc2⁺-MSC or Ac-G5-BSA-coated Luc2⁺-MSC at various time points. <b>B</b>. Quantitative data of bioluminescence signals in each group (n = 4/group) at various time points. <b>C</b>. Bioluminescence imaging shows Ac-G5-dendrimer-sE-sel nanocarrier-coated Luc2⁺-MSC selectively homed to skin wound tissues but not other organs, as demonstrated by IVIS scanning of the harvested lung, heart, liver, spleen, kidney, femur, normal and wounded skins on Day 8.</p

Nanocarrier-mediated cell-cell binding <i>in vitro</i>.

<p>A. Schematic illustration of the design of nanocarriers with a representative image of the desired biological readout. “Mono-arm” (Ac-G5-dendrimer-sE-sel, <i>Left</i>) and “double-arm” (Ac-G5-dendrimer-sE-sel/VEGF, <i>Right</i>) for EPC coating. <b>B.</b> <i>In vitro</i> EPC-EC binding assay. “Mono-arm” and “double-arm” nanocarrier-decorated DsRad⁺ EPC displayed an increased binding capability to EC monolayer. E-selectin blocking antibody inhibited nanocarrier-mediated association of EPC-EC. Quantitative data of DsRed signals. Data are presented as mean ± SD of three independent assays in which samples were duplicated. <i>Insert</i>: Representative images of DsRed fluorescence in wells.</p

Coating cell surface with nanocarriers.

<p><b>A</b>. Schematic illustration for the design of nanocarrier for cell coating. <b>B</b> & <b>C</b>. Murine MSC were coated with albumin-Alexa-488 conjugated Ac-G5-dendrimer nanocarriers and subjected to image analysis 3-hour afterward. Cell membrane binding and the sustained surface stay of the nanocarriers were assessed by 2 methods. TEM imaging is shown in <b>B</b>. Arrows point to Ac-G5-dendrimer-BSA binding on the cell surface. Confocal imaging is shown in <b>C</b>. <i>Left</i>: Top: a orthogonal view of stacks of confocal images showing Ac-G5-dendrimer-BSA localization at the cell surface; Bottom: a surface confocal imaging of coated MSC (X40). <i>Right</i>: 3D overview of confocal z-stack imaging of coated MSC (X40).</p