In-situ crosslinking hydrogels for combinatorial delivery of chemokines and siRNA-DNA carrying microparticles to dendritic cells

ArticleinBiomaterials 30(28):5187-200 · July 2009with18 Reads
DOI: 10.1016/j.biomaterials.2009.06.001 · Source: PubMed
Polymer-based, injectable systems that can simultaneously deliver multiple bioactive agents in a controlled manner could significantly enhance the efficacy of next generation therapeutics. For immunotherapies to be effective, both prophylactically or therapeutically, it is not only critical to drive the antigen (Ag)-specific immune response strongly towards either T helper type 1 (Th1) or Th2 phenotype, but also to promote recruitment of a high number of antigen-presenting cells (APCs) at the site of immunization. We have recently reported a microparticle-based system capable of simultaneously delivering siRNA and DNA to APCs. Here we present an in-situ crosslinkable, injectable formulation containing dendritic cell (DC)-chemo-attractants and dual-mode DNA-siRNA loaded microparticles to attract immature DCs and simultaneously deliver, to the migrated cells, immunomodulatory siRNA and plasmid DNA antigens. These low crosslink density hydrogels were designed to degrade within 2-7 days in vitro and released chemokines in a sustained manner. Chemokine carrying gels attracted 4-6 folds more DCs over a sustained period in vitro, compared to an equivalent bolus dose. Interestingly, migrated DCs were able to infiltrate the hydrogels and efficiently phagocytose the siRNA-DNA carrying microparticles. Hydrogel embedded microparticles co-delivering Interleukin-10 siRNA and plasmid DNA antigens exhibited efficient Interleukin-10 gene knockdown in migrated primary DCs in vitro.
    • "For example, they can be coated with chemoattractants (e.g. CCL19, CCL20, CCL21) that specifically stimulate DC accumulation to the area of administration in vivo [60,61], and once taken up, the microparticle can release its tolerogenic payload with or without the provision of antigens. Finally, microparticles can also be programmed to release their various contents at different times after in vivo injection. "
    [Show abstract] [Hide abstract] ABSTRACT: We have developed novel antisense oligonucleotide-formulated microspheres that can reverse hyperglycemia in newly-onset diabetic mice. Dendritic cells taking up the microspheres adopt a restrained co-stimulation ability and migrate to the pancreatic lymph nodes when injected into an abdominal region that is drained by those lymph nodes. Furthermore, we demonstrate that the absolute numbers of antigen-specific Foxp3+ T regulatory cells are increased only in the lymph nodes draining the site of administration and that these T-cells proliferate independently of antigen supply in the microspheres. Taken together, our data add to the emerging model where antigen supply may not be a requirement in "vaccines" for autoimmune disease, but the site of administration - subserved by lymph nodes draining the target organ - is in fact critical to foster the generation of antigen-specific regulatory cells. The implications of these observations on "vaccine" design for autoimmunity are discussed and summarized. Copyright © 2015. Published by Elsevier Inc.
    Full-text · Article · Mar 2015
    • "A promising approach is to locally engineer CK gradients with the goal of promoting the accumulation of key immune players, such as DCs and neutrophils, or eliciting cascades of immune responses to eliminate pathogens or tumors567. Recent advances in nanotechnology now offer innovative ways to reach this goal using controlled-release materials to engineer CK gradients for basic studies and therapeutic applications89101112. It has been reported that biodegradable NPs providing a sustained release of various CKs are able to direct in vitro migration of dendritic cells (DCs), monocytes (DC precursors), and T cells [8,9]. "
    [Show abstract] [Hide abstract] ABSTRACT: Chemokines (CKs) secreted by the host cells into surrounding tissue establish concentration gradients directing the migration of leukocytes. We propose an in vivo CK gradient remodeling approach based on sustained release of CKs by the crosslinked poly(N-isopropylacrylamide) hydrogel open meshwork nano-particles (NPs) containing internal crosslinked dye affinity baits for a reversible CK binding and release. The sustained release is based on a new principle of affinity off-rate tuning. The NPs with Cibacron Blue F3G-A and Reactive Blue-4 baits demonstrated a low-micromolar affinity binding to IL-8, MIP-2, and MCP-1 with a half-life of several hours at 37°C. The capacity of NPs loaded with IL-8 and MIP-1α to increase neutrophil recruitment to lymph nodes (LNs) was tested in mice after footpad injection. Fluorescently-labeled NPs used as tracers indicated the delivery into the sub-capsular compartment of draining LNs. The animals administered the CK-loaded NPs demonstrated a widening of the sub-capsular space and a strong lymph node influx of leukocytes, while mice injected with control NPs without CKs or bolus doses of soluble CKs alone showed only a marginal neutrophil response. This technology provides a new means therapeutically direct or restore immune cell traffic, and can also be employed for simultaneous therapy delivery.
    Full-text · Article · Mar 2015
    • "In addition, the encapsulation of polymer particles may increase their biocompatibility by " hiding " them within the polymer networks and also prevents rapid clearance of the particles at the site of interest in vivo [279]. Hybrid hydrogels have been used to modulate the release of small molecule drugs [280,281], genetic material282283284, proteins285286287 and vaccines [288]. These systems also allow for delivery of multiple different bioactive agents with independent release rates [289]. "
    [Show abstract] [Hide abstract] ABSTRACT: Polymer hydrogels have been widely explored as therapeutic delivery matrices because of their ability to present sustained, localized and controlled release of bioactive factors. Bioactive factor delivery from injectable biopolymer hydrogels provides a versatile approach to treat a wide variety of diseases, to direct cell function and to enhance tissue regeneration. The innovative development and modification of both natural- (e.g., alginate (ALG), chitosan, hyaluronic acid (HA), gelatin, heparin (HEP), etc.) and synthetic- (e.g., polyesters, polyethyleneimine (PEI), etc.) based polymers has resulted in a variety of approaches to design drug delivery hydrogel systems from which loaded therapeutics are released. This review presents the state-of-the-art in a wide range of hydrogels that are formed though self-assembly of polymers and peptides, chemical crosslinking, ionic crosslinking and biomolecule recognition. Hydrogel design for bioactive factor delivery is the focus of the first section. The second section then thoroughly discusses release strategies of payloads from hydrogels for therapeutic medicine, such as physical incorporation, covalent tethering, affinity interactions, on demand release and/or use of hybrid polymer scaffolds, with an emphasis on the last 5 years.
    Full-text · Article · Jul 2014
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