Pro-Inflammatory Versus Anti-Inflammatory Effects of Dendrimers: The Two Faces of Immuno-Modulatory Nanoparticles

Enhanced Immunomodulatory Effects of Thymosin-Alpha-1 in Combination with Polyanionic Carbosilane Dendrimers against HCMV Infection

Resistance and toxicity associated with current treatments for human cytomegalovirus (HCMV) infection highlight the need for alternatives and immunotherapy has emerged as a promising strategy. This study examined the in vitro immunological effects of co-administration of Thymosin-alpha-1 (Tα1) and polyanionic carbosilane dendrimers (PCDs) on peripheral blood mononuclear cells (PBMCs) during HCMV infection. The biocompatibility of PCDs was assessed via MTT and LDH assays. PBMCs were pre-treated with the co-administered compounds and then exposed to HCMV for 48 h. Morphological alterations in PBMCs were observed using optical microscopy and total dendritic cells (tDCs), myeloid dendritic cells (mDCs), and plasmacytoid dendritic cells (pDCs), along with CD4+/CD8+ T cells and regulatory T cells (Treg), and were characterized using multiparametric flow cytometry. The findings revealed that Tα1 + PCDs treatments increased DC activation and maturation. Furthermore, increased co-receptor expression, intracellular IFNγ production in T cells and elevated Treg functionality and reduced senescence were evident with Tα1 + G2-S24P treatment. Conversely, reduced co-receptor expression, intracellular cytokine production in T cells, lower functionality and higher senescence in Treg were observed with Tα1 + G2S16 treatment. In summary, Tα1 + PCDs treatments demonstrate synergistic effects during early HCMV infection, suggesting their use as an alternative therapeutic for preventing virus infection.

Methotrexate and Sulforaphane loaded PBA-G5-PAMAM dendrimers as a combination therapy for anti-inflammatory response in an intra-articular joint arthritic animal model

L-sulforaphane (LSF), a natural product developed from cruciferous vegetables, have shown potent anti-inflammatory effect in cancer as well as arthritis. However, the stable delivery of LSF remains a major challenge. Methotrexate (MTX) is currently the first line treatment for managing RA and is most effective in patients when used in combination with other anti-inflammatory or anti-rheumatic drugs. Here we developed phenylboronic acid-PAMAM dendrimer (PBA-G5D) nanoparticles conjugated MTX (MTX-PBA-G5D), and L-sulforaphane (LSF/PBA-G5D) loaded dendrimers. The MTX and LSF drug loading and release kinetics was analyzed using HPLC. The lipopolysaccharide (LPS) stimulated macrophages were treated with the formulations to study the inflammatory response in vitro. For in vivo studies, arthritis was induced in five-week-old female Wistar rats, and the MTX- and LSF/PBA-G5-D were injected via intra-articular injection for treatment and the arthritis reduction was scored by weight, knee diameter, and serum cytokine level measurement. The average size of the drug-nanoparticle conjugates ranged from 135-250 nm, with mostly cationic surface charges. The encapsulation efficiency of the drugs to the modified dendrimer was more than 60% with a slow release of drugs from the nanoparticles within 24 h at pH 7.4. Drugs in the nanoparticle formulation were biocompatible, with promising anti-inflammatory effects in vitro against LPS-activated murine macrophages. Further in vivo studies on arthritis induced female Wistar rats, revealed significant anti-arthritic effects based on the arthritic scoring from the knee diameter reading, and anti-inflammatory effects based on the serum cytokine levels. This study provides a promising strategy for utilizing PAMAM dendrimers as a nanocarrier for LSF delivery for RA therapy.

Curing inflammatory diseases using phosphorous dendrimers

Different types of water-soluble phosphorous dendrimers have been synthesized and display many different biological properties. It has been shown in particular that phosphorous dendrimers of first generation functionalized with azabisphosphonate terminal functions are able to stimulate the human immune system ex vivo. These dendrimers are internalized by monocytes within a few seconds, and induce their anti-inflammatory activation. The presence of the dendrimers induces also the inhibition of the differentiation of monocytes into osteoclasts, the maturation of dendritic cells, and inhibits the proliferation of the proinflammatory CD4⁺ T lymphocytes. Finally, after 2-3 weeks of culture of peripheral blood mononuclear cells, amplifications by several tens of natural killer cells is observed. In view of all these properties, the influence of these azabisphosphonate-dendrimers has been tested in vivo with several animal models, against different chronic or acute inflammatory diseases, such as multiple sclerosis, rheumatoid arthritis, uveitis, and psoriasis, but also against myeloid leukemia, a hematological cancer. The hematological safety has been demonstrated in mice, as there is no platelet aggregation, no hemolysis, and no disturbance in the hematological formula. The safety of the azabisphosphonate-dendrimer has been assessed also with non-human primates (cynomolgus monkeys) which received repeated injections, as a de-risking pre-clinical test. Biochemical, hematological, and all immunological parameters in peripheral blood remained within a normal physiological range throughout the study, and all survived well. Other phosphorous dendrimers also display anti-inflammatory properties in vivo, in particular dendrimers functionalized with mannose derivatives, which prevent acute lung diseases when given orally (per os) to mice. This article is categorized under: Nanotechnology Approaches to Biology > Nanoscale Systems in Biology Therapeutic Approaches and Drug Discovery > Emerging Technologies Therapeutic Approaches and Drug Discovery > Nanomedicine for Neurological Disease.

Dendrimers as nanoscale vectors: Unlocking the bars of cancer therapy

Chemotherapy is the first choice in the treatment of cancer and is always preferred to other approaches such as radiation and surgery, but it has never met the need of patients for a safe and effective drug. Therefore, new advances in cancer treatment are now needed to reduce the side effects and burdens associated with chemotherapy for cancer patients. Targeted treatment using nanotechnology are now being actively explored as they could effectively deliver therapeutic agents to tumor cells without affecting normal cells. Dendrimers are promising nanocarriers with distinct physiochemical properties that have received considerable attention in cancer therapy studies, which is partly due to the numerous functional groups on their surface. In this review, we discuss the progress of different types of dendrimers as delivery systems in cancer therapy, focusing on the challenges, opportunities, and functionalities of the polymeric molecules. The paper also reviews the various role of dendrimers in their entry into cells via endocytosis, as well as the molecular and inflammatory pathways in cancer. In addition, various dendrimers-based drug delivery (e.g., pH-responsive, enzyme-responsive, redox-responsive, thermo-responsive, etc.) and lipid-, amino acid-, polymer- and nanoparticle-based modifications for gene delivery, as well as co-delivery of drugs and genes in cancer therapy with dendrimers, are presented. Finally, biosafety concerns and issues hindering the transition of dendrimers from research to the clinic are discussed to shed light on their clinical applications.

Repolarization of Unbalanced Macrophages: Unmet Medical Need in Chronic Inflammation and Cancer

Monocytes and their tissue counterpart macrophages (MP) constitute the front line of the immune system. Indeed, they are able to rapidly and efficiently detect both external and internal danger signals, thereby activating the immune system to eradicate the disturbing biological, chemical, or physical agents. They are also in charge of the control of the immune response and account for the repair of the damaged tissues, eventually restoring tissue homeostasis. The balance between these dual activities must be thoroughly controlled in space and time. Any sustained unbalanced response of MP leads to pathological disorders, such as chronic inflammation, or favors cancer development and progression. In this review, we take advantage of our expertise in chronic inflammation, especially in rheumatoid arthritis, and in cancer, to highlight the pivotal role of MP in the physiopathology of these disorders and to emphasize the repolarization of unbalanced MP as a promising therapeutic strategy to control these diseases.

Insights into Interactions between Interleukin-6 and Dendritic Polyglycerols

Interleukin-6 (IL-6) is involved in physiological and pathological processes. Different pharmacological agents have been developed to block IL-6 deleterious effects and to recover homeostatic IL-6 signaling. One of the proposed nanostructures in pre-clinical investigations which reduced IL-6 concentrations is polyglycerol dendrimer, a nano-structure with multiple sulfate groups. The aim of the present study was to uncover the type of binding between critical positions in the human IL-6 structure available for binding dPGS and compare it with heparin sulfate binding. We studied these interactions by performing docking simulations of dPGS and heparins with human IL-6 using AutoDock Vina. These molecular docking analyses indicate that the two ligands have comparable affinities for the positively charged positions on the surface of IL-6. All-atom molecular dynamics simulations (MD) employing Gromacs were used to explore the binding sites and binding strengths. Results suggest two major binding sites and show that the strengths of binding are similar for heparin and dPGS (−5.5–6.4 kcal/ mol). dPGS or its analogs could be used in the therapeutic intervention in sepsis and inflammatory disorders to reduce unbound IL-6 in the plasma or tissues and its binding to the receptors. We propose that analogs of dPGS could specifically block IL-6 binding in the desired signaling mode and would be valuable new probes to establish optimized therapeutic intervention in inflammation.

Dendritic Polymers as Promising Additives for the Manufacturing of Hybrid Organoceramic Nanocomposites with Ameliorated Properties Suitable for an Extensive Diversity of Applications

As the field of nanoscience is rapidly evolving, interest in novel, upgraded nanomaterials with combinatory features is also inevitably increasing. Hybrid composites, offer simple, budget-conscious and environmental-friendly solutions that can cater multiple needs at the same time and be applicable in many nanotechnology-related and interdisciplinary studies. The physicochemical idiocrasies of dendritic polymers have inspired their implementation as sorbents, active ingredient carriers and templates for complex composites. Ceramics are distinguished for their mechanical superiority and absorption potential that render them ideal substrates for separation and catalysis technologies. The integration of dendritic compounds to these inorganic hosts can be achieved through chemical attachment of the organic moiety onto functionalized surfaces, impregnation and absorption inside the pores, conventional sol-gel reactions or via biomimetic mediation of dendritic matrices, inducing the formation of usually spherical hybrid nanoparticles. Alternatively, dendritic polymers can propagate from ceramic scaffolds. All these variants are covered in detail. Optimization techniques as well as established and prospected applications are also presented.

Supramolecular and Macromolecular Matrix Nanocarriers for Drug Delivery in Inflammation-Associated Skin Diseases

Skin is our biggest organ. It interfaces our body with its environment. It is an efficient barrier to control the loss of water, the regulation of temperature, and infections by skin-resident and environmental pathogens. The barrier function of the skin is played by the stratum corneum (SC). It is a lipid barrier associating corneocytes (the terminally differentiated keratinocytes) and multilamellar lipid bilayers. This intricate association constitutes a very cohesive system, fully adapted to its role. One consequence of this efficient organization is the virtual impossibility for active pharmaceutical ingredients (API) to cross the SC to reach the inner layers of the skin after topical deposition. There are several ways to help a drug to cross the SC. Physical methods and chemical enhancers of permeation are a possibility. These are invasive and irritating methods. Vectorization of the drugs through nanocarriers is another way to circumvent the SC. This mini-review focuses on supramolecular and macromolecular matrices designed and implemented for skin permeation, excluding vesicular nanocarriers. Examples highlight the entrapment of anti-inflammatory API to treat inflammatory disorders of the skin.

Biomedical nanomaterials for immunological applications: ongoing research and clinical trials

Research efforts on nanomaterial-based therapies for the treatment of autoimmune diseases and cancer have spiked and have made rapid progress over the past years. Nanomedicine has been shown to contribute significantly to overcome current therapeutic limitations, exhibiting advantages compared to conventional therapeutics, such as sustained drug release, delayed drug degradation and site-specific drug delivery. Multiple nanodrugs have reached the clinic, but translation is often hampered by either low targeting efficiency or undesired side effects. Nanomaterials, and especially inorganic nanoparticles, have gained criticism due to their potential toxic effects, including immunological alterations. However, many strategies have been attempted to improve the therapeutic efficacy of nanoparticles and exploit their unique properties for the treatment of inflammation and associated diseases. In this review, we elaborate on the immunomodulatory effects of nanomaterials, with a strong focus on the underlying mechanisms that lead to these specific immune responses. Nanomaterials to be discussed include inorganic nanoparticles such as gold, silica and silver, as well as organic nanomaterials such as polymer-, dendrimer-, liposomal- and protein-based nanoparticles. Furthermore, various approaches for tuning nanomaterials in order to enhance their efficacy and attenuate their immune stimulation or suppression, with respect to the therapeutic application, are described. Additionally, we illustrate how the acquired insights have been used to design immunotherapeutic strategies for a variety of diseases. The potential of nanomedicine-based therapeutic strategies in immunotherapy is further illustrated by an up to date overview of current clinical trials. Finally, recent efforts into enhancing immunogenic cell death through the use of nanoparticles are discussed.

Synthesis, Internalization and Visualization of N-(4-Carbomethoxy) Pyrrolidone Terminated PAMAM [G5:G3-TREN] Tecto(dendrimers) in Mammalian Cells

Tecto(dendrimers) are well-defined, dendrimer cluster type covalent structures. In this article, we present the synthesis of such a PAMAM [G5:G3-(TREN)]-N-(4-carbomethoxy) pyrrolidone terminated tecto(dendrimer). This tecto(dendrimer) exhibits nontraditional intrinsic luminescence (NTIL; excitation 376 nm; emission 455 nm) that has been attributed to three fluorescent components characterized by different fluorescence lifetimes. Furthermore, it has been shown that this PAMAM [G5:G3-(TREN)]-N-(4-carbomethoxy) pyrrolidone terminated tecto(dendrimer) is able to form a polyplex with double stranded DNA, and is nontoxic for HeLa and HMEC-1 cells up to a concentration of 10 mg/mL, even though it accumulates in endosomal compartments as demonstrated by its unique NTIL emission properties. Many of the above features would portend the proposed use of this tecto(dendrimer) as an efficient transfection agent. Quite surprisingly, transfection activity could not be demonstrated in HeLa cells, and the possible reasons are discussed in the article.

An Anti-Inflammatory Poly(PhosphorHydrazone) Dendrimer Capped with AzaBisPhosphonate Groups to Treat Psoriasis

Dendrimers are nanosized, arborescent macromolecules synthesized in a stepwise fashion with attractive degrees of functionality and structure definition. This is one of the reasons why they are widely used for biomedical applications. Previously, we have shown that a poly(phosphorhydrazone) (PPH) dendrimer capped with anionic azabisphosphonate groups (so-called ABP dendrimer) has immuno-modulatory and anti-inflammatory properties towards human immune cells in vitro. Thereafter, we have shown that the ABP dendrimer has a promising therapeutic efficacy to treat models of acute and chronic inflammatory disorders in animal models. In these models, the active pharmaceutical ingredient was administered systematically (intravenous and oral administrations), but also loco-regionally in the vitreous tissue. Herein, we assessed the therapeutic efficacy of the ABP dendrimer in the preclinical mouse model of psoriasis induced by imiquimod. The ABP dendrimer was administered in phosphate-buffered saline solution via either systemic injection or topical application. We show that the topical application enabled the control of both the clinical and histopathological scores, and the control of the infiltration of macrophages in the skin of treated mice.

Materials for Immunotherapy

Breakthroughs in materials engineering have accelerated the progress of immunotherapy in preclinical studies. The interplay of chemistry and materials has resulted in improved loading, targeting, and release of immunomodulatory agents. An overview of the materials that are used to enable or improve the success of immunotherapies in preclinical studies is presented, from immunosuppressive to proinflammatory strategies, with particular emphasis on technologies poised for clinical translation. The materials are organized based on their characteristic length scale, whereby the enabling feature of each technology is organized by the structure of that material. For example, the mechanisms by which i) nanoscale materials can improve targeting and infiltration of immunomodulatory payloads into tissues and cells, ii) microscale materials can facilitate cell-mediated transport and serve as artificial antigen-presenting cells, and iii) macroscale materials can form the basis of artificial microenvironments to promote cell infiltration and reprogramming are discussed. As a step toward establishing a set of design rules for future immunotherapies, materials that intrinsically activate or suppress the immune system are reviewed. Finally, a brief outlook on the trajectory of these systems and how they may be improved to address unsolved challenges in cancer, infectious diseases, and autoimmunity is presented.

Tumor immune microenvironment modulation-based drug delivery strategies for cancer immunotherapy

The past years have witnessed promising clinical feedback for anti-cancer immunotherapies, which have become one of the hot research topics; however, they are limited by poor delivery kinetics, narrow patient response profiles, and systemic side effects. To the best of our knowledge, the development of cancer is highly associated with the immune system, especially the tumor immune microenvironment (TIME). Based on the comprehensive understanding of the complexity and diversity of TIME, drug delivery strategies focused on the modulation of TIME can be of great significance for directing and improving cancer immunotherapy. This review highlights the TIME modulation in cancer immunotherapy and summarizes the versatile TIME modulation-based cancer immunotherapeutic strategies, medicative principles and accessory biotechniques for further clinical transformation. Remarkably, the recent advances of cancer immunotherapeutic drug delivery systems and future prospects of TIME modulation-based drug delivery systems for much more controlled and precise cancer immunotherapy will be emphatically discussed.

Dendritic polyglycerols are modulators of microglia-astrocyte crosstalk

Aim: To determine the ability of sulfated dendritic polyglycerols (dPGS) to modulate neuroglia activation challenged with lipopolysaccharide (LPS). Materials & methods: Microglia/astrocyte activation in vivo was determined in transgenic animals expressing TLR2-/GFAP-luciferase reporter. Mechanisms implicated in microglia-astrocyte crosstalk were studied in primary mouse brain cultures. Results & discussion: dPGS significantly reduced microglia activation in vivo, and decreased astrocytic LCN2 production. Activated microglia are necessary for astrocyte stimulation and increase in LCN2 abundance. LCN2 production in astrocytes involves signaling via toll-like receptor 4, activation of NF-κB, IL6 and enhancement of reactive oxygen species. Conclusion: dPGS are powerful modulators of microglia-astrocyte crosstalk and LCN2 abundance; dPGS are promising anti-inflammatory dendritic nanostructures.

Biodistribution and Biosafety of a Poly(Phosphorhydrazone) Dendrimer, an Anti-Inflammatory Drug-Candidate

Dendrimers are nanosized, arborescent polymers of which size and structure are perfectly controlled. This is one reason why they are widely used for biomedical purposes. Previously, we showed that a phosphorus-based dendrimer capped with anionic azabisphosphonate groups (so-called ABP dendrimer) has immuno-modulatory and anti-inflammatory properties towards human immune cells in vitro. Thereafter, we have shown that the ABP dendrimer has a promising therapeutic efficacy to treat models of chronic inflammatory disorders. On the way to clinical translation, the biodistribution and the safety of this drug-candidate has to be thoroughly assessed. In this article, we present preliminary non-clinical data regarding biodistribution, hematological safety, genotoxicity, maximal tolerated doses, and early cardiac safety of the ABP dendrimer. One of the genotoxicity assays reveals a potential mutagen effect of the item at a concentration above 200 µM, i.e., up to 100 times the active dose in vitro on human immune cells. However, as the results obtained for all the other assays show that the ABP dendrimer has promising biodistribution and safety profiles, there is no red flag raised to hamper the regulatory pre-clinical development of the ABP dendrimer.

Leveraging the interplay of nanotechnology and neuroscience: Designing new avenues for treating central nervous system disorders

Nanotechnology has the potential to open many novel diagnostic and treatment avenues for disorders of the central nervous system (CNS). In this review, we discuss recent developments in the applications of nanotechnology in CNS therapies, diagnosis and biology. Novel approaches for the diagnosis and treatment of neuroinflammation, brain dysfunction, psychiatric conditions, brain cancer, and nerve injury provide insights into the potential of nanomedicine. We also highlight nanotechnology-enabled neuroscience techniques such as electrophysiology and intracellular sampling to improve our understanding of the brain and its components. With nanotechnology integrally involved in the advancement of basic neuroscience and the development of novel treatments, combined diagnostic and therapeutic applications have begun to emerge. Nanotheranostics for the brain, able to achieve single-cell resolution, will hasten the rate in which we can diagnose, monitor, and treat diseases. Taken together, the recent advances highlighted in this review demonstrate the prospect for significant improvements to clinical diagnosis and treatment of a vast array of neurological diseases. However, it is apparent that a strong dialogue between the nanoscience and neuroscience communities will be critical for the development of successful nanotherapeutics that move to the clinic, benefit patients, and address unmet needs in CNS disorders.

Multivalent nanosystems: targeting monocytes/macrophages

Among all the cellular partners involved in inflammatory processes, monocytes and macrophages are the master regulators of inflammation. They are found in almost all the tissues and are nearly the only cells capable of performing each step of inflammation. Consequently, they stand as major relevant therapeutic targets to treat inflammatory disorders and diseases. The physiological phagocytic activity of macrophages prompts them to detect, to recognize, and eventually to engulf any nanosystem cruising in their neighborhood. Interestingly, nanosystems can be rationally engineered to afford multivalent, and multifunctional if needed, entities with multiplexed and/or reinforced biological activities. Indeed, engineered nanosystems bearing moieties specifically targeting macrophages, and loaded with or bound to drugs are promising candidates to modulate, or even eradicate, deleterious macrophages in vivo. In this review we highlight recent articles and concepts of multivalent nanosystems targeting monocytes and macrophages to treat inflammatory disorders.

The ABP Dendrimer, a Drug-Candidate against Inflammatory Diseases That Triggers the Activation of Interleukin-10 Producing Immune Cells

The ABP dendrimer, which is built on a phosphorus-based scaffold and bears twelve azabisphosphonate groups at its surface, is one of the dendrimers that has been shown to display immuno-modulatory and anti-inflammatory effects towards the human immune system. Its anti-inflammatory properties have been successfully challenged in animal models of inflammatory disorders. In this review, we trace the discovery and the evaluation of the therapeutic effects of the ABP dendrimer in three different animal models of both acute and chronic inflammatory diseases. We emphasize that its therapeutic effects rely on the enhancement of the production of Interleukin-10, the paradigm of anti-inflammatory cytokines, by different subsets of immune cells, such as monocytes/macrophages and CD4+ T lymphocytes.

Role of Nanotechnology in Cosmeceuticals: A Review of Recent Advances

Nanotechnology manifests the progression in the arena of research and development, by increasing the efficacy of the product through delivery of innovative solutions. To overcome certain drawbacks associated with the traditional products, application of nanotechnology is escalating in the area of cosmeceuticals. Cosmeceuticals are regarded as the fastest growing segment of the personal care industry and the use has risen drastically over the years. Nanocosmeceuticals used for skin, hair, nail, and lip care, for conditions like wrinkles, photoaging, hyperpigmentation, dandruff, and hair damage, have come into widespread use. Novel nanocarriers like liposomes, niosomes, nanoemulsions, microemulsion, solid lipid nanoparticles, nanostructured lipid carrier, and nanospheres have replaced the usage of conventional delivery system. These novel nanocarriers have advantages of enhanced skin penetration, controlled and sustained drug release, higher stability, site specific targeting, and high entrapment efficiency. However, nanotoxicological researches have indicated concern regarding the impact of increased use of nanoparticles in cosmeceuticals as there are possibilities of nanoparticles to penetrate through skin and cause health hazards. This review on nanotechnology used in cosmeceuticals highlights the various novel carriers used for the delivery of cosmeceuticals, their positive and negative aspects, marketed formulations, toxicity, and regulations of nanocosmeceuticals.

Three-Dimensional Directionality Is a Pivotal Structural Feature for the Bioactivity of Azabisphosphonate-Capped Poly(PhosphorHydrazone) Nanodrug Dendrimers

Dendrimers are nanosized, nonlinear, hyperbranched polymers whose overall 3D shape is key for their biological activity. Poly(PhosphorHydrazone) (PPH) dendrimers capped with aza-bisphosphonate (ABP) end groups are known to have anti-inflammatory properties enabling the control of inflammatory diseases in different mouse models. Here we screen the anti-inflammatory activity of a series of PPH dendrimers bearing between 2 and 16 ABP end groups in a mouse model of arthritis and confront the biological results with atomistic simulations of the dendrimers. We show that only the PPH dendrimers capped with 10 and 12 ABP end groups can control the flare of the inflammatory disease. All-atom accelerated molecular dynamics simulations show that dendrimers with a low number of ABP end groups are directional but highly flexible/dynamic and have thereby limited efficiency in establishing multivalent interactions. The largest dendrimer appears as nondirectional, having 16 ABP end groups forming patches all over the dendrimer surface. Conversely, intermediate dendrimers having 10 or 12 ABP end groups reach the best compromise between the number of surface groups and their stable directional gathering, a real maximization of multivalency.