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A major shortcoming in the treatment of mesangial cell-associated diseases such as IgA nephropathy, diabetic nephropathy, or lupus nephritis, which frequently progress to end-stage renal disease, is poor drug availability in the glomerular mesangium. Drug delivery via active targeting of nanoparticles, using ligands attached to the particle surface for target cell recognition to increase the biodistribution to the mesangium, is a promising strategy to overcome this hurdle. However, although several glomerular tissue targeting approaches have been described, so far no study has demonstrated the particles' ability to deliver sufficient drug amounts combined with an appropriate nanoparticle target retention time to trigger relevant biological effects in the mesangium. In our study, we encapsulated erastin, a ferroptosis-inducing model compound, into adenovirus-mimetic, mesangial cell-targeting nanoparticles, enabling the direct visualisation of biological effects through ferroptosis-dependent histological changes. By intravital microscopy and analysis of histological sections, we were not only able to localise the injected particles over 10 days within the target cells but also to demonstrate biological activity in the renal glomeruli. In conclusion, we have characterised adenovirus-mimetic nanoparticles as a highly suitable drug delivery platform for the treatment of mesangial cell-associated diseases and additionally provided the basis for a potential renal disease model.
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A major bottleneck diminishing the therapeutic efficacy of various drugs is that only small proportions of the administered dose reach the site of action. One promising approach to increase the drug amount in the target tissue is the delivery via nanoparticles (NPs) modified with ligands of cell surface receptors for the selective identification of target cells. However, since receptor binding can unintentionally trigger intracellular signaling cascades, our objective was to develop a receptor-independent way of NP uptake. Cell-penetrating peptides (CPPs) are an attractive tool since they allow efficient cell membrane crossing. So far, their applicability is severely limited as their uptake-promoting ability is nonspecific. Therefore, we aimed to achieve a conditional CPP-mediated NP internalization exclusively into target cells. We synthesized different CPP candidates and investigated their influence on nanoparticle stability, ζ-potential, and uptake characteristics in a core-shell nanoparticle system consisting of poly(lactid-co-glycolid) (PLGA) and poly(lactic acid)-poly(ethylene glycol) (PLA10kPEG2k) block copolymers with CPPs attached to the PEG part. We identified TAT47-57 (TAT) as the most promising candidate and subsequently combined the TAT-modified PLA10kPEG2k polymer with longer PLA10kPEG5k polymer chains, modified with the potent angiotensin-converting enzyme 2 (ACE2) inhibitor MLN-4760. While MLN-4760 enables selective target cell identification, the additional PEG length hides the CPP during a first unspecific cell contact. Only after the previous selective binding of MLN-4760 to ACE2, the established spatial proximity exposes the CPP, triggering cell uptake. We found an 18-fold uptake improvement in ACE2-positive cells compared to unmodified particles. In summary, our work paves the way for a conditional and thus highly selective receptor-independent nanoparticle uptake, which is beneficial in terms of avoiding side effects.
Assuntos
Peptídeos Penetradores de Células , Nanopartículas , Peptídeos Penetradores de Células/química , Peptídeos Penetradores de Células/farmacologia , Humanos , Nanopartículas/química , Polietilenoglicóis/química , Copolímero de Ácido Poliláctico e Ácido Poliglicólico/químicaRESUMO
Immunization is a straightforward concept but remains for some pathogens like HIV-1 a challenge. Thus, new approaches towards increasing the efficacy of vaccines are required to turn the tide. There is increasing evidence that antigen exposure over several days to weeks induces a much stronger and more sustained immune response compared to traditional bolus injection, which usually leads to antigen elimination from the body within a couple of days. Therefore, we developed a poly(ethylene) glycol (PEG) hydrogel platform to investigate the principal feasibility of a sustained release of antigens to mimic natural infection kinetics. Eight-and four-armed PEG macromonomers of different MWs (10, 20, and 40 kDa) were end-group functionalized to allow for hydrogel formation via covalent cross-linking. An HIV-1 envelope (Env) antigen in its trimeric (Envtri) or monomeric (Envmono) form was applied. The soluble Env antigen was compared to a formulation of Env attached to silica nanoparticles (Env-SiNPs). The latter are known to have a higher immunogenicity compared to their soluble counterparts. Hydrogels were tunable regarding the rheological behavior allowing for different degradation times and release timeframes of Env-SiNPs over two to up to 50 days. Affinity measurements of the VCR01 antibody which specifically recognizes the CD4 binding site of Env, revealed that neither the integrity nor the functionality of Envmono-SiNPs (Kd = 2.1 ± 0.9 nM) and Envtri-SiNPs (Kd = 1.5 ± 1.3 nM), respectively, were impaired after release from the hydrogel (Kd before release: 2.1 ± 0.1 and 7.8 ± 5.3 nM, respectively). Finally, soluble Env and Env-SiNPs which are two physico-chemically distinct compounds, were co-delivered and shown to be sequentially released from one hydrogel which could be beneficial in terms of heterologous immunization or single dose vaccination. In summary, this study presents a tunable, versatile applicable, and effective delivery platform that could improve vaccination effectiveness also for other infectious diseases than HIV-1.
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Vacinas contra a AIDS , Preparações de Ação Retardada , HIV-1 , Hidrogéis , Nanopartículas , Polietilenoglicóis , Hidrogéis/química , Nanopartículas/química , Vacinas contra a AIDS/administração & dosagem , Vacinas contra a AIDS/imunologia , Vacinas contra a AIDS/química , Polietilenoglicóis/química , HIV-1/imunologia , Dióxido de Silício/química , Humanos , Liberação Controlada de Fármacos , Produtos do Gene env do Vírus da Imunodeficiência Humana/imunologia , Produtos do Gene env do Vírus da Imunodeficiência Humana/químicaRESUMO
The specific delivery of a drug to its site of action also known as targeted drug delivery is a topic in the field of pharmaceutics studied for decades. One approach extensively investigated in this context is the use ligand functionalized nanoparticles. These particles are modified to carry receptor specific ligands, enabling them to accumulate at a desired target site. However, while this concept initially appears straightforward to implement, in-depth research has revealed several challenges hindering target site specific particle accumulation - some of which remain unresolved to this day. One of these challenges consists in the still incomplete understanding of how nanoparticles interact with biological systems. This knowledge gap significantly compromises the predictability of particle distribution in biological systems, which is critical for therapeutic efficacy. One of the most crucial steps in delivery is the attachment of nanoparticles to cells at the target site. This attachment occurs via the formation of multiple ligand receptor bonds. A process also referred to as multivalent interaction. While multivalency has been described extensively for individual molecules and macromolecules respectively, little is known on the multivalent binding of nanoparticles to cells. Here, we will specifically introduce the concept of avidity as a measure for favorable particle membrane interactions. Also, an overview about nanoparticle and membrane properties affecting avidity will be given. Thereafter, we provide a thorough review on literature investigating the correlation between nanoparticle avidity and success in targeted particle delivery. In particular, we want to analyze the currently uncertain data on the existence and nature of the correlation between particle avidity and biodistribution.
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Nanopartículas , Sistemas de Liberação de Medicamentos , Ligantes , Nanopartículas/química , Distribuição Tecidual , IncertezaRESUMO
Pharmacotherapy is often limited by undesired side effects while insufficient drug reaches the site of action. Active-targeted nanotherapy should provide a solution for this problem, by using ligands in the nanoparticle corona for the identification of receptors on the target-cell surface. However, since receptor binding is directly associated with pharmacological responses, today's targeting concepts must be critically evaluated. We hypothesized that addressing ectoenzymes would help to overcome this problem, but it was not clear if particles would show sufficiently high avidity to provide us with a viable alternative to classical ligand-receptor concepts. We scrutinized this aspect by immobilizing the highly selective angiotensin-converting enzyme 2 (ACE2) inhibitor MLN-4760 in the corona of block-copolymer nanoparticles and investigated enzyme binding via microscale thermophoresis and flow cytometry. Excellent avidities with Kd values as low as 243 pM for soluble ACE2 and 306 pM for ACE2-positive cells were obtained. In addition, the inhibitory activity had an IC50 value of 2.88 nM. Reliable target cell identification could be proven in coculture experiments. High avidity is the basis for minimizing material loss to off-target sites and paves the way for a paradigm shift in nanoparticle targeting which does not trigger unintended side effects following target cell identification.
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Enzima de Conversão de Angiotensina 2 , Nanopartículas , Polímeros/química , Nanopartículas/química , Ligantes , Ligação ProteicaRESUMO
Interferon-γ (IFN-γ) is well known to reduce the infectivity of viral pathogens by altering their tissue tropism. This effect is induced by upregulation of cholesterol 25-hydroxylase (CH25H). Given the similarity of viral pathogens and ligand-functionalized nanoparticles in the underlying strategy of receptor-mediated cell recognition, it appears conceivable that IFN-γ exceeds similar effects on nanoparticles. Concretely, IFN-γ-induced activation of CH25H could decrease nanoparticle avidity for target cells via depletion of clathrin-coated pits. We hypothesized that this effect would cause deterioration of target-cell specific accumulation of nanoparticles. To prove our hypothesis, we investigated the cell tropism of angiotensin II functionalized nanoparticles (NPLys-Ang II) in a co-culture system of angiotensin II subtype 1 receptor (AT1R) positive rat mesangial target cells (rMCs) and AT1R-negative HeLa off-target cells. In the presence of IFN-γ we observed an up to 5-fold loss of target cell preference for NPLys-Ang II. Thus, our in vitro results suggest a strong influence of IFN-γ on nanoparticle distribution, which is relevant in the context of nanotherapeutic approaches to cancer treatment, as IFN-γ is strongly expressed in tumors. For the target cell tropism of viruses, our results provide a conclusive hypothesis for the underlying mechanism behind non-directed viral distribution in the presence of IFN-γ.
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Atherosclerosis is one of the most urgent global health subjects, causes millions of deaths worldwide, and is associated with enormous healthcare costs. Macrophages are the root cause for inflammatory onset and progression of the disease but are not addressed by conventional therapy. Therefore, we used pioglitazone, which is a drug initially used for diabetes therapies, but at the same time has great potential regarding the mitigation of inflammation. As yet, this potential of pioglitazone cannot be exploited, as drug concentrations at the target site in vivo are not sufficient. To overcome this shortcoming, we established PEG-PLA/PLGA-based nanoparticles loaded with pioglitazone and tested them in vitro. Encapsulation of the drug was analyzed by HPLC and revealed an outstanding encapsulation efficiency of 59% into the nanoparticles, which were 85 nm in size and had a PDI of 0.17. Further, uptake of our loaded nanoparticles in THP-1 macrophages was comparable to the uptake of unloaded nanoparticles. On the mRNA level, pioglitazone-loaded nanoparticles were superior to the free drug by 32% in increasing the expression of the targeted receptor PPAR-γ. Thereby the inflammatory response in macrophages was ameliorated. In this study, we take the first step toward an anti-inflammatory, causal antiatherosclerotic therapy, using the potential of the already established drug pioglitazone, and enable it to enrich at the target site by using nanoparticles. An additional crucial feature of our nanoparticle platform is the versatile modifiability of ligands and ligand density, to achieve an optimal active targeting effect in the future.
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Aterosclerose , Nanopartículas , Humanos , Pioglitazona/farmacologia , Pioglitazona/uso terapêutico , Polímeros/farmacologia , Aterosclerose/tratamento farmacológico , Aterosclerose/genética , Aterosclerose/metabolismo , MacrófagosRESUMO
Inflammation and immune system activation are key pathologic events in the onset and escalation of diabetic retinopathy (DR). Both are driven by cytokines and complement originating from the retinal pigment epithelium (RPE). Despite the RPE's pivotal role, there is no therapeutic tool to specifically interfere with the RPE-related pathomechanism. A therapy that addresses RPE cells and counteracts inflammation and immune response would be of paramount value for the early treatment of DR, where currently are no specific therapies available. Here, we utilized lipoprotein-mimetic lipid nanocapsules to deliver the anti-inflammatory and immunosuppressive drug cyclosporin A (CsA) to RPE cells. Using a mouse model of DR that mirrors all pathologic aspects of human DR, we demonstrate that intravenously applied CsA-loaded lipid nanocapsules comprehensively counteract inflammation and immune system activation. One single injection suppressed the expression of pro-inflammatory cytokines, dampened macrophage infiltration, and prevented macrophage and microglia activation in eyes with DR. This work shows that CsA-loaded lipid nanocapsules can offer new avenues for the treatment of DR.
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Diabetes Mellitus , Retinopatia Diabética , Nanocápsulas , Animais , Humanos , Retinopatia Diabética/tratamento farmacológico , Ciclosporina/uso terapêutico , Nanocápsulas/uso terapêutico , Injeções Intravenosas , Inflamação/tratamento farmacológico , Modelos Animais de Doenças , Citocinas , Sistema Imunitário/metabolismo , Sistema Imunitário/patologia , Lipídeos , Diabetes Mellitus/tratamento farmacológicoRESUMO
Water-free preparation of protein delivery systems has the potential to overcome the limitations of hydrogel depot systems such as off-target reactions, functional group hydrolysis, and limited loading capacity. However, a major roadblock in the development and use of these systems is administration as implantation is often required. In this study, we developed a biodegradable and water-free injectable protein delivery system via inverse electron demand Diels-Alder reaction between norbornene- and tetrazine-functionalized four-armed poly(ethylene glycol) macromonomers. 1:1 mixtures of these precursors gelled rapidly in situ, taking less than 11 s to reach their gelation point. Methyl substitution of tetrazine slowed the gelation time and increased the cross-linking density, whereas oxygen incorporation into norbornene changed the mechanical properties. Introduction of hydrolytically cleavable groups enabled biodegradability. Using phenyl carbamate and phenyl carbonate ester groups, we could tune the stability. Controlled release of the protein surrogate glucose oxidase was achieved over a period of 500 days. The novel preparation method presented here is a promising step toward the development of water-free injectable protein depots for controlled drug delivery.
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Polietilenoglicóis , Polímeros , Preparações de Ação Retardada , Hidrogéis , Sistemas de Liberação de Medicamentos , ProteínasRESUMO
The paramount relevance of clathrin-coated pits (CCPs) to receptor-mediated endocytosis of nanoparticles, extracellular vesicles, and viruses has made them the focus of many studies; however, the role of CCP geometry in the ligand-receptor interactions between multivalent nanoparticles and cells has not been investigated. We hypothesized the general dependence of nanoparticle binding energy on local membrane curvature to be expandable to the specific case of ligand-functionalized nanoparticles binding cell membranes, in the sense that membrane structures whose curvature matches that of the particle (e.g., CCPs) signficantly contribute to binding avidity. We investigated this hypothesis with nanoparticles that bind multivalently to angiotensin II receptor type 1, which is subject to clathrin-mediated endocytosis. When we used cholesterol extraction to prevent the action of CCPs, we found a 67 to 100-fold loss in avidity. We created a theoretical model that predicts this decrease based on the loss of ligand-receptor interactions when CCPs, which perfectly match nanoparticle geometry, are absent. Our findings shed new light on how cells "see" nanoparticles. The presence or absence of CPPs is so influential on how cells interact with nanoparticles that the number of particles required to be visible to cells changes by two orders of magnitude depending on CCP presence.
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Clatrina , Nanopartículas , Clatrina/metabolismo , Ligantes , Membrana Celular/metabolismo , EndocitoseRESUMO
Eight-armed poly(ethylene glycol) (PEG) hydrogels cross-linked via inverse electron demand Diels-Alder reaction between norbornene and tetrazine groups are promising materials for long-term protein delivery. While a controlled release over 265 days is achieved for 15% w/v hydrogels in the previous study, the material shows high stability over 500 days despite having cleavable ester linkages between the PEG macromonomers and their functionalities. In this study, the hydrolyzable ester linkers in the PEG-norbornene precursor structure are exchanged to reduce the degradation time. To this end, 3,6-epoxy-1,2,3,6-tetrahydrophthalimide, phenyl carbamate, carbonate ester, and phenyl carbonate ester are introduced as degradable functional groups. Oscillatory shear experiments reveal that they are not affected the in situ gelation. All hydrogel types have gel points of less than 20 s even at a low polymer concentration of 5% w/v. Hydrogels with varying polymer concentrations have similar mesh sizes, all of which fell in the range of 4-12 nm. The inclusion of phenyl carbonate ester accelerates degradation considerably, with complete dissolution of 15% w/v hydrogels after 302 days of incubation in phosphate buffer (pH 7.4). Controlled release of 150 kDa fluorescein isothiocyanate-dextran over a period of at least 150 days is achieved with 15% w/v hydrogels.
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Elétrons , Hidrogéis , Reação de Cicloadição , Preparações de Ação Retardada/química , Hidrogéis/química , Polietilenoglicóis/química , Norbornanos , Materiais Biocompatíveis , Polímeros , ÉsteresRESUMO
Retinopathy of prematurity (ROP) is a retinal disease that threatens the vision of prematurely born infants. Severe visual impairment up to complete blindness is caused by neovascularization and inflammation, progressively destroying the immature retina. ROP primarily affects newborns in middle- and low-income countries with limited access to current standard treatments such as intraocular drug injections and laser- or cryotherapy. To overcome these limitations, we developed a nanotherapeutic that effectively prevents ROP development with one simple intravenous injection. Its lipid nanocapsules transport the antiangiogenic and anti-inflammatory cyclosporin A efficiently into disease-driving retinal pigment epithelium cells. In a mouse model of ROP, a single intravenous injection of the nanotherapeutic prevented ROP and led to normal retinal development by counteracting neovascularization and inflammation. This nanotherapeutic approach has the potential to bring about a change of paradigm in ROP therapy and prevent millions of preterm born infants from developing ROP.
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Nanocápsulas , Retinopatia da Prematuridade , Animais , Ciclosporina/farmacologia , Ciclosporina/uso terapêutico , Humanos , Recém-Nascido , Inflamação/tratamento farmacológico , Injeções Intravenosas , Lipídeos , Camundongos , Nanocápsulas/uso terapêutico , Retinopatia da Prematuridade/tratamento farmacológico , Retinopatia da Prematuridade/prevenção & controle , Fator A de Crescimento do Endotélio VascularRESUMO
The retinal pigment epithelium (RPE) plays a crucial part in sight-threatening diseases. In this review, we shed light on the pivotal implication of the RPE in age-related macular degeneration, diabetic retinopathy and retinopathy of prematurity; and explain why a paradigm shift toward targeted RPE therapy is needed to efficiently fight these retinal diseases. We provide guidance for the development of RPE-specific nanotherapeutics by giving a comprehensive overview of the possibilities and challenges of drug delivery to the RPE and highlight successful nanotherapeutic approaches targeting the RPE.
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Retinopatia Diabética , Degeneração Macular , Humanos , Recém-Nascido , Epitélio Pigmentado da RetinaRESUMO
Nanoparticles hold great potential as vaccine carriers due to their highly versatile structure and the possibility to influence intracellular trafficking and antigen presentation by their design. In this study, we developed a nanoparticulate system with a new enzyme-triggered antigen release mechanism. For this novel approach, nanoparticle and model antigen ovalbumin were linked with a substrate of the early endosomal protease cathepsin S. This construct enabled the transfer of antigens delivered to bone marrow-derived dendritic cells from the endo-lysosomal compartments in the cytosol. Consecutively, our particles enhanced cross-presentation on dendritic cells and subsequently promoted a stronger activation of CD8+ T cells. Our findings suggest that enzyme-triggered antigen release allows the endosomal escape of the antigen, leading to increased MHC-I presentation. Since T cell immunity is central for the control of viral infections and cancer, this release mechanism offers a promising approach for the development of both prophylactic and therapeutic vaccines.
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Apresentação Cruzada , Vacinas , Animais , Apresentação de Antígeno , Antígenos , Linfócitos T CD8-Positivos , Células Dendríticas , Camundongos , Camundongos Endogâmicos C57BL , Ovalbumina/químicaRESUMO
Off-target interactions between reactive hydrogel moieties and drug cargo as well as slow reaction kinetics and the absence of controlled protein release over an extended period of time are major drawbacks of chemically cross-linked hydrogels for biomedical applications. In this study, the inverse electron demand Diels-Alder (iEDDA) reaction between norbornene- and tetrazine-functionalized eight-armed poly(ethylene glycol) (PEG) macromonomers was used to overcome these obstacles. Oscillatory shear experiments revealed that the gel point of a 15% (w/v) eight-armed PEG hydrogel with a molecular weight of 10 kDa was less than 15 s, suggesting the potential for fast in situ gelation. However, the high-speed reaction kinetics result in a risk of premature gel formation that complicates the injection process. Therefore, we investigated the effect of polymer concentration, temperature, and chemical structure on the gelation time. The cross-linking reaction was further characterized regarding bioorthogonality. Only 11% of the model protein lysozyme was found to be PEGylated by the iEDDA reaction, whereas 51% interacted with the classical Diels-Alder reaction. After determination of the mesh size, fluorescein isothiocyanate-dextran was used to examine the release behavior of the hydrogels. When glucose oxidase was embedded into 15% (w/v) hydrogels, a controlled release over more than 250 days was achieved. Overall, the PEG-based hydrogels cross-linked via the fast iEDDA reaction represent a promising material for the long-term administration of biologics.
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Elétrons , Hidrogéis , Peso Molecular , Polietilenoglicóis , ProteínasRESUMO
The development of nanomedical devices has led to a considerable number of clinically applied nanotherapeutics. Yet, the overall poor translation of nanoparticular concepts into marketable systems has not met the initial expectations and led to increasing criticism in recent years. Most novel nano approaches thereby use highly refined formulations including a plethora of active targeting sequences, but ultimately fail to reach their target due to a generally high off-target deposition in organs such as the liver or kidney. In this context, we argue that initial nanoparticle (NP) development should not entirely become set on conventional formulation aspects. In contrast, we propose a change of focus towards a prior analysis of general sites of NP in vivo deposition and an assessment of how accumulation in these organs or tissues can be harnessed to develop therapies for site-related pathologies. We therefore give a comprehensive overview of existing nanotherapeutic targeting strategies for specific cell types within three of the usual suspects, i.e. the liver, kidney and the vascular system. We discuss the physiological surroundings and relevant pathologies of described tissues as well as the implications for NP-mediated drug delivery. Additionally, successful cell-selective NP concepts using active targeting strategies are assessed. By bringing together both (patho)physiological aspects and concepts for cell-selective NP formulations, we hope to show a novel opportunity for the development of more promising nanotherapeutic devices.
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Sistemas de Liberação de Medicamentos/métodos , Nanomedicina , Nanopartículas , Disponibilidade Biológica , Vasos Sanguíneos/citologia , Vasos Sanguíneos/metabolismo , Humanos , Rim/citologia , Rim/metabolismo , Fígado/citologia , Fígado/metabolismo , Nanomedicina/métodos , Nanomedicina/tendências , Nanopartículas/administração & dosagem , Nanopartículas/metabolismo , Distribuição TecidualRESUMO
Diabetic nephropathy (DN) ranks among the most detrimental long-term effects of diabetes, affecting more than 30% of all patients. Within the diseased kidney, intraglomerular mesangial cells play a key role in facilitating the pro-fibrotic turnover of extracellular matrix components and a progredient glomerular hyperproliferation. These pathological effects are in part caused by an impaired functionality of soluble guanylate cyclase (sGC) and a consequentially reduced synthesis of anti-fibrotic messenger 3',5'-cyclic guanosine monophosphate (cGMP). Bay 58-2667 (cinaciguat) is able to re-activate defective sGC; however, the drug suffers from poor bioavailability and its systemic administration is linked to adverse events such as severe hypotension, which can hamper the therapeutic effect. In this study, cinaciguat was therefore efficiently encapsulated into virus-mimetic nanoparticles (NPs) that are able to specifically target renal mesangial cells and therefore increase the intracellular drug accumulation. NP-assisted drug delivery thereby increased in vitro potency of cinaciguat-induced sGC stabilization and activation, as well as the related downstream signaling 4- to 5-fold. Additionally, administration of drug-loaded NPs provided a considerable suppression of the non-canonical transforming growth factor ß (TGF-ß) signaling pathway and the resulting pro-fibrotic remodeling by 50-100%, making the system a promising tool for a more refined therapy of DN and other related kidney pathologies.
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Benzoatos/administração & dosagem , Sistemas de Liberação de Medicamentos , Células Mesangiais/efeitos dos fármacos , Células Mesangiais/metabolismo , Guanilil Ciclase Solúvel/metabolismo , Animais , Benzoatos/farmacocinética , Materiais Biomiméticos , Células Cultivadas , GMP Cíclico/metabolismo , Nefropatias Diabéticas/tratamento farmacológico , Nefropatias Diabéticas/metabolismo , Nefropatias Diabéticas/patologia , Ativação Enzimática/efeitos dos fármacos , Estabilidade Enzimática/efeitos dos fármacos , Fibrose , Humanos , Células Mesangiais/patologia , Modelos Biológicos , Nanopartículas/administração & dosagem , Ratos , Transdução de Sinais/efeitos dos fármacos , Fator de Crescimento Transformador beta/metabolismoRESUMO
Atherosclerosis is the leading cause of death in developed countries. The pathogenetic mechanism relies on a macrophage-based immune reaction to low density lipoprotein (LDL) deposition in blood vessels with dysfunctional endothelia. Thus, atherosclerosis is defined as a chronic inflammatory disease. A plethora of cardiovascular drugs have been developed and are on the market, but the major shortcoming of standard medications is that they do not address the root cause of the disease. Statins and thiazolidinediones that have recently been recognized to exert specific anti-atherosclerotic effects represent a potential breakthrough on the horizon. But their whole potential cannot be realized due to insufficient availability at the pathological site and severe off-target effects. The focus of this review will be to elaborate how both groups of drugs could immensely profit from nanoparticulate carriers. This delivery principle would allow for their accumulation in target macrophages and endothelial cells of the atherosclerotic plaque, increasing bioavailability where it is needed most. Based on the analyzed literature we conclude design criteria for the delivery of statins and thiazolidinediones with nanoparticles for anti-atherosclerotic therapy. Nanoparticles need to be below a diameter of 100 nm to accumulate in the atherosclerotic plaque and should be fabricated using biodegradable materials. Further, the thiazolidinediones or statins must be encapsulated into the particle core, because especially for thiazolidindiones the uptake into cells is prerequisite for their mechanism of action. For optimal uptake into targeted macrophages and endothelial cells, the ideal particle should present ligands on its surface which bind specifically to scavenger receptors. The impact of statins on the lectin-type oxidized LDL receptor 1 (LOX1) seems particularly promising because of its outstanding role in the inflammatory process. Using this pioneering concept, it will be possible to promote the impact of statins and thiazolidinediones on macrophages and endothelial cells and significantly enhance their anti-atherosclerotic therapeutic potential.
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Aterosclerose , Fármacos Cardiovasculares , Placa Aterosclerótica , Aterosclerose/tratamento farmacológico , Células Endoteliais , Humanos , Lipoproteínas LDL , NanotecnologiaRESUMO
A root cause for the development and progression of primary open-angle glaucoma might be the loss of the Schlemm's canal (SC) cell function due to an impaired Angiopoietin-1 (Angpt-1)/Tie2 signaling. Current therapeutic options fail to restore the SC cell function. We propose Angpt-1 mimetic nanoparticles (NPs) that are intended to bind in a multivalent manner to the Tie2 receptor for successful receptor activation. To this end, an Angpt-1 mimetic peptide was coupled to a poly(ethylene glycol)-poly(lactic acid) (PEG-PLA) block co-polymer. The modified polymer allowed for the fabrication of Angpt-1 mimetic NPs with a narrow size distribution (polydispersity index < 0.2) and the size of the NPs ranging from about 120 nm (100% ligand density) to about 100 nm (5% ligand density). NP interaction with endothelial cells (HUVECs, EA.hy926) as surrogate for SC cells and fibroblasts as control was investigated by flow cytometry and confocal microscopy. The NP-cell interaction strongly depended on the ligand density and size of NPs. The cellular response to the NPs was investigated by a Ca2+ mobilization assay as well as by a real-time RT-PCR and Western blot analysis of endothelial nitric oxide synthase (eNOS). NPs with a ligand density of 25% opposed VEGF-induced Ca2+ influx in HUVECs significantly which could possibly increase cell relaxation and thus aqueous humor drainage, whereas the expression and synthesis of eNOS was not significantly altered. Therefore, we suggest Angpt-1 mimetic NPs as a first step towards a causative therapy to recover the loss of SC cell function during glaucoma.
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Viruses are nanomaterials with a number of properties that surpass those of many synthetic nanoparticles (NPs) for biomedical applications. They possess a rigorously ordered structure, come in a variety of shapes, and present unique surface elements, such as spikes. These attributes facilitate propitious biodistribution, the crossing of complex biological barriers and a minutely coordinated interaction with cells. Due to the orchestrated sequence of interactions of their stringently arranged particle corona with cellular surface receptors they effectively identify and infect their host cells with utmost specificity, while evading the immune system at the same time. Furthermore, their efficacy is enhanced by their response to stimuli and the ability to spread from cell to cell. Over the years, great efforts have been made to mimic distinct viral traits to improve biomedical nanomaterial performance. However, a closer look at the literature reveals that no comprehensive evaluation of the benefit of virus-mimetic material design on the targeting efficiency of nanomaterials exists. In this review we, therefore, elucidate the impact that viral properties had on fundamental advances in outfitting nanomaterials with the ability to interact specifically with their target cells. We give a comprehensive overview of the diverse design strategies and identify critical steps on the way to reducing them to practice. More so, we discuss the advantages and future perspectives of a virus-mimetic nanomaterial design and try to elucidate if viral mimicry holds the key for better NP targeting.