Icam-1 targeted nanogels loaded with dexamethasone alleviate pulmonary inflammation

Abstract

Lysozyme dextran nanogels (NG) have great potential in vitro as a drug delivery platform, combining simple chemistry with rapid uptake and cargo release in target cells with "stealth" properties and low toxicity. In this work, we study for the first time the potential of targeted NG as a drug delivery platform in vivo to alleviate acute pulmonary inflammation in animal model of LPS-induced lung injury. NG are targeted to the endothelium via conjugation with an antibody (Ab) directed to Intercellular Adhesion Molecule-1(ICAM-NG), whereas IgG conjugated NG (IgG-NG) are used for control formulations. The amount of Ab conjugated to the NG and distribution in the body after intravenous (IV) injection have been quantitatively analyzed using a tracer isotope-labeled [125I]IgG. As a proof of concept, Ab-NG are loaded with dexamethasone, an anti-inflammatory therapeutic, and the drug uptake and release kinetics are measured by HPLC. In vivo studies in mice showed that: i) ICAM-NG accumulates in mouse lungs (∼120% ID/g vs ∼15% ID/g of IgG-NG); and, ii) DEX encapsulated in ICAM-NG, but not in IgG-NG practically blocks LPS-induced overexpression of pro-inflammatory cell adhesion molecules including ICAM-1 in the pulmonary inflammation.

Figure 1. Schematic illustrating the conjugation of Ab to NG and loading of DEX.

Figure 2. Characterization of Ab-NG.

(a) Size distribution of nanogel before (NG) and after Ab coating (Ab-NG), as measured by DLS. The particle size (z-average) is 137 nm (pdi = 0.081) and 160 nm (pdi = 0.095) for NG and Ab-NG, respectively. (b) Summary of anti-ICAM coverage of NGs, [¹²⁵I]IgG conjugation increases with [¹²⁵I]IgG added to the NGs. Representative cryo-TEM images of NG before (c) and after (d) anti-ICAM coating (ICAM-NG). Scale bar: 50 nm.

Figure 3. In vivo targeting of [¹²⁵I]Ab-NG.

Organ uptake of [¹²⁵I]ICAM-1 targeted and [¹²⁵I]IgG-NG were analyzed at 30 min post-IV administration. **p<0.005, *p<0.05.

Figure 4. In vitro DEX release kinetics of IgG-NG in 1 wt% BSA/PBS.

The red line is extended Langmuir model fit.

Figure 5. In vivo VCAM and ICAM protein expression in lung tissue for naïve and LPS-treated (+LPS) mice following injection for the different treatments studied.

(a) Representative Western blot detection, (b) summary of % protection for VCAM expression, (c) summary of % protection for ICAM expression. *p<0.05.