Immunostimulatory activity of Y-shaped DNA nanostructures mediated through the activation of TLR9

Macrophage-Targeting DNA Nanomaterials: A Future Direction of Biological Therapy

DNA can be used for precise construction of complex and flexible micro-nanostructures, including DNA origami, frame nucleic acids, and DNA hydrogels. DNA nanomaterials have good biocompatibility and can enter macrophages via scavenger receptor-mediated endocytosis. DNA nanomaterials can be uniquely and flexibly designed to ensure efficient uptake by macrophages, which represents a novel strategy to regulate macrophage function. With the development of nanotechnology, major advances have been made in the design and manufacturing of DNA nanomaterials for clinical therapy. In diseases accompanied by macrophage disturbances including tumor, infectious diseases, arthritis, fibrosis, acute lung injury, and atherosclerosis, DNA nanomaterials received considerable attention as potential treatments. However, we lack sufficient information to guarantee precise targeting of macrophages by DNA nanomaterials, which precludes their therapeutic applications. In this review, we summarize recent studies of macrophage-targeting DNA nanomaterials and discuss the limitations and challenges of this approach with regard to its potential use as a biological therapy.

DNA-directed assembly of nanomaterials and their biomedical applications

In the past decades, DNA has been widely used in the field of nanostructures due to its unique programmable properties. Besides being used to form its own diverse structures such as the assembly of DNA origami, DNA can also be used for the assembly of nanostructures with other materials. In this review, different strategies for the functionalization of DNA on nanoparticle surfaces are listed, and the roles of DNA in the assembly of nanostructures as well as the influencing factors are discussed. Finally, the biomedical applications of DNA-assembled nanostructures were summarized. This review provided new insight into the application of DNA in nanostructure assembly.

Innate Immune Stimulation Using 3D Wireframe DNA Origami

Three-dimensional wireframe DNA origami have programmable structural and sequence features that render them potentially suitable for prophylactic and therapeutic applications. However, their innate immunological properties, which stem from parameters including geometric shape and cytosine-phosphate-guanine dinucleotide (CpG) content, remain largely unknown. Here, we investigate the immunostimulatory properties of 3D wireframe DNA origami on the TLR9 pathway using both reporter cell lines and primary immune cells. Our results suggest that bare 3D polyhedral wireframe DNA origami induce minimal TLR9 activation despite the presence of numerous internal CpG dinucleotides. However, when displaying multivalent CpG-containing ssDNA oligos, wireframe DNA origami induce robust TLR9 pathway activation, along with enhancement of downstream immune response as evidenced by increases in Type I and Type III interferon (IFN) production in peripheral blood mononuclear cells. Further, we find that CpG copy number and spatial organization each contribute to the magnitude of TLR9 signaling and that NANP-attached CpGs do not require phosphorothioate stabilization to elicit signaling. These results suggest key design parameters for wireframe DNA origami that can be programmed to modulate immune pathway activation controllably for prophylactic and therapeutic applications.

DNA Origami Nanostructures Elicit Dose-Dependent Immunogenicity and Are Nontoxic up to High Doses In Vivo

DNA origami (DO) nanotechnology enables the construction of precise nanostructures capable of functionalization with small molecule drugs, nucleic acids, and proteins, suggesting a promising platform for biomedical applications. Despite the potential for drug and vaccine delivery, the impact of DO vehicles on immunogenicity in vivo is not well understood. Here, two DO vehicles, a flat triangle and a nanorod, at varying concentrations are evaluated in vitro and with a repeated dosing regimen administered at a high dose in vivo to study early and late immunogenicity. The studies show normal CD11b⁺ myeloid cell populations preferentially internalize DO in vitro. DO structures distribute well systemically in vivo, elicit a modest pro-inflammatory immune response that diminishes over time and are nontoxic as shown by weight, histopathology, lack of cytokine storm, and a complete biochemistry panel at the day 10 end point. The results take critical steps to characterize the biological response to DO and suggest that DO vehicles represent a promising platform for drug delivery and vaccine development where immunogenicity should be a key consideration.

Recent advances in cancer immunotherapy: Modulation of tumor microenvironment by Toll-like receptor ligands

Immunotherapy is considered a promising approach for cancer treatment. An important strategy for cancer immunotherapy is the use of cancer vaccines, which have been widely used for cancer treatment. Despite the great potential of cancer vaccines for cancer treatment, their therapeutic effects in clinical settings have been limited. The main reason behind the lack of significant therapeutic outcomes for cancer vaccines is believed to be the immunosuppressive tumor microenvironment (TME). The TME counteracts the therapeutic effects of immunotherapy and provides a favorable environment for tumor growth and progression. Therefore, overcoming the immunosuppressive TME can potentially augment the therapeutic effects of cancer immunotherapy in general and therapeutic cancer vaccines in particular. Among the strategies developed for overcoming immunosuppression in TME, the use of toll-like receptor (TLR) agonists has been suggested as a promising approach to reverse immunosuppression. In this paper, we will review the application of the four most widely studied TLR agonists including agonists of TLR3, 4, 7, and 9 in cancer immunotherapy.

Engineering DNA Nanostructures to Manipulate Immune Receptor Signaling and Immune Cell Fates

Immune cells sense, communicate, and logically integrate a multitude of environmental signals to make important cell-fate decisions and fulfill their effector functions. These processes are initiated and regulated by a diverse array of immune receptors and via their dynamic spatiotemporal organization upon ligand binding. Given the widespread relevance of the immune system to health and disease, there have been significant efforts toward understanding the biophysical principles governing immune receptor signaling and activation, as well as the development of biomaterials which exploit these principles for therapeutic immune engineering. Here, how advances in the field of DNA nanotechnology constitute a growing toolbox for further pursuit of these endeavors is discussed. Key cellular players involved in the induction of immunity against pathogens or diseased cells are first summarized. How the ability to design DNA nanostructures with custom shapes, dynamics, and with site-specific incorporation of diverse guests can be leveraged to manipulate the signaling pathways that regulate these processes is then presented. It is followed by highlighting emerging applications of DNA nanotechnology at the crossroads of immune engineering, such as in vitro reconstitution platforms, vaccines, and adjuvant delivery systems. Finally, outstanding questions that remain for further advancing immune-modulatory DNA nanodevices are outlined.

Smart biomaterials to enhance the efficiency of immunotherapy in glioblastoma: State of the art and future perspectives

Glioblastoma multiform (GBM) is considered as the most lethal tumor among CNS malignancies. Although immunotherapy has achieved remarkable advances in cancer treatment, it has not shown satisfactory results in GBM patients. Biomaterial science, along with nanobiotechnology, is able to optimize the efficiency of immunotherapy in these patients. They can be employed to provide the specific activation of immune cells in tumor tissue and combinational therapy as well as preventing systemic adverse effects resulting from hyperactivation of immune responses and off-targeting effect. Advance biomaterials in this field are classified into targeting nanocarriers and localized delivery systems. This review will offer an overview of immunotherapy strategies for glioblastoma and advance delivery systems for immunotherapeutics that may have a high potential in glioblastoma treatment.

Prospective Cancer Therapies Using Stimuli-Responsive DNA Nanostructures

Nanostructures based on DNA self-assembly present an innovative way to address the increasing need for target-specific delivery of therapeutic molecules. Currently, most of the chemotherapeutics being used in clinical practice have undesired and exceedingly high off-target toxicity. This is a challenge in particular for small molecules, and hence, developing robust and effective methods to lower these side effects and enhance the antitumor activity is of paramount importance. Prospectively, these issues could be tackled with the help of DNA nanotechnology, which provides a route for the fabrication of custom, biocompatible, and multimodal structures, which can, to some extent, resist nuclease degradation and survive in the cellular environment. Similar to widely employed liposomal products, the DNA nanostructures (DNs) are loaded with selected drugs, and then by employing a specific stimulus, the payload can be released at its target region. This review explores several strategies and triggers to achieve targeted delivery of DNs. Notably, different modalities are explained through which DNs can interact with their respective targets as well as how structural changes triggered by external stimuli can be used to achieve the display or release of the cargo. Furthermore, the prospects and challenges of this technology are highlighted.

Para-phenylenediamine, an oxidative hair dye ingredient, increases thymic stromal lymphopoietin and proinflammatory cytokines causing acute dermatitis

Due to high consumption of cosmetics in modern society, people are always exposed to the risk of skin damage and complications. Para-phenylenediamine (P-PD), an ingredient of hair dye, has been reported to cause allergic contact dermatitis. However, the mechanism has not been well elucidated. Here, we identify that P-PD causes dermatitis by increasing thymic stromal lymphopoietin (TSLP) and inflammatory cytokines. Topical application of P-PD to mouse ear skin in consecutive 5 days resulted in dermatitis symptoms and increased ear thickness. TSLP production in skin was upregulated by P-PD treatment alone. In addition, P-PD-induced TSLP production was potentiated by MC903, which is an in vivo TSLP inducer. P-PD increased TSLP production in keratinocytes (KCMH-1 cells and phorbol 12-myristate 13-acetate-stimulated PAM212 cells). The production of proinflammatory cytokines such as IL-1β, IL-6, IFN-γ, and CCL2, was upregulated by P-PD treatment together with MC903. The results show that repeated exposure to P-PD causes acute contact dermatitis mediated by increasing the expression of TSLP and proinflammatory cytokines.

DNA Nanostructure as an Efficient Drug Delivery Platform for Immunotherapy

Immunotherapy has received increasing attention due to its low potential side effects and high specificity. For instance, cancer immunotherapy has achieved great success. CpG is a well-known and commonly used immunotherapeutic and vaccine adjuvant, but it has the disadvantage of being unstable and low in efficacy and needs to be transported through an effective nanocarrier. With perfect structural programmability, permeability, and biocompatibility, DNA nanostructures are one of the most promising candidates to deliver immune components to realize immunotherapy. However, the instability and low capability of the payload of ordinary DNA assemblies limit the relevant applications. Consequently, DNA nanostructure with a firm structure, high drug payloads is highly desirable. In the paper, the latest progress of biostable, high-payload DNA nanoassemblies of various structures, including cage-like DNA nanostructure, DNA particles, DNA polypods, and DNA hydrogel, are reviewed. Cage-like DNA structures hold drug molecules firmly inside the structure and leave a large space within the cavity. These DNA nanostructures use their unique structure to carry abundant CpG, and their biocompatibility and size advantages to enter immune cells to achieve immunotherapy for various diseases. Part of the DNA nanostructures can also achieve more effective treatment in conjunction with other functional components such as aPD1, RNA, TLR ligands.