Sebastian Fuchs

Targeting CpG Oligonucleotides to the Lymph Node by Nanoparticles Elicits Efficient Antitumoral Immunity

Viral nucleic acids are recognized by specific pattern-recognition receptors of the Toll-like and RIG-I-like receptor families. Synthetic DNA and RNA oligonucleotides can activate the immune system through these receptors and potentiate Ab and CD8 cytotoxic responses to Ags. Systemic application of immunostimulatory oligonucleotides however also results in a generalized, non-Ag-specific stimulation of the immune system. In this study, we have dissociated the induction of an Ag-specific response from the systemic immune activation generally associated with immunostimulatory oligonucleotides. Delivery of CpG oligodeoxynucleotides that bind TLR9 by cationized gelatin-based nanoparticles potentiates the in vivo generation of an Ag-specific cytotoxic T cell and Ab response. Furthermore, immunization with CpG-loaded nanoparticles induces a protective antitumoral response in a murine model of melanoma. The systemic release of proinflammatory cytokines and widespread immunostimulation associated with free CpG is however completely abolished. In addition, we show that gelatin nanoparticle formulation prevents the destruction of lymphoid follicles mediated by CpG. Nanoparticle-delivered CpG, in contrast to free CpG, are selectively targeted to APCs in the lymph nodes where they mediate local immune stimulation. We describe a novel strategy to target immunostimulatory oligonucleotides to the initiation site of the immune response while at the same time protecting from an indiscriminate and generalized activation of the immune system.

A novel technique for selective NF-κB inhibition in Kupffer cells: contrary effects in fulminant hepatitis and ischaemia–reperfusion

Background and aims: The transcription factor nuclear factor kappa B (NF-κB) has risen as a promising target for anti-inflammatory therapeutics. In the liver, however, NF-κB inhibition mediates both damaging and protective effects. The outcome is deemed to depend on the liver cell type addressed. Recent gene knock-out studies focused on the role of NF-κB in hepatocytes, whereas the role of NF-κB in Kupffer cells has not yet been investigated in vivo. Here we present a novel approach, which may be suitable for clinical application, to selectively target NF-κB in Kupffer cells and analyse the effects in experimental models of liver injury. Methods: NF-κB inhibiting decoy oligodeoxynucleotides were loaded upon gelatin nanoparticles (D-NPs) and their in vivo distribution was determined by confocal microscopy. Liver damage, NF-κB activity, cytokine levels and apoptotic protein expression were evaluated after lipopolysaccharide (LPS), d-galactosamine (GalN)/LPS, or concanavalin A (ConA) challenge and partial warm ischaemia and subsequent reperfusion, respectively. Results: D-NPs were selectively taken up by Kupffer cells and inhibited NF-κB activation. Inhibition of NF-κB in Kupffer cells improved survival and reduced liver injury after GalN/LPS as well as after ConA challenge. While anti-apoptotic protein expression in liver tissue was not reduced, pro-apoptotic players such as cJun N-terminal kinase (JNK) were inhibited. In contrast, selective inhibition of NF-κB augmented reperfusion injury. Conclusions: NF-κB inhibiting decoy oligodeoxynucleotide-loaded gelatin nanoparticles is a novel tool to selectively inhibit NF-κB activation in Kupffer cells in vivo. Thus, liver injury can be reduced in experimental fulminant hepatitis, but increased at ischaemia–reperfusion.

Delivery of immunostimulatory RNA oligonucleotides by gelatin nanoparticles triggers an efficient antitumoral response.

RNA oligonucleotides have emerged as a new class of biologicals that can silence gene expression but also stimulate immune responses through specific pattern-recognition receptors. The development of effective delivery systems remains a major challenge for the therapeutic application of the RNA oligonucleotides. In this study, we have established a novel biodegradable carrier system that is highly effective for the delivery of immunostimulatory RNA oligonucleotides. Formulation of RNA oligonucleotides with cationized gelatin nanoparticles potentiates immune activation through the Toll-like receptor 7 (TLR7) in both myeloid and plasmacytoid dendritic cells. Further, nanoparticle-delivered RNA oligonucleotides trigger production of the antitumoral cytokines IL-12 and IFN-α. Binding to gelatin nanoparticles protects RNA oligonucleotides from degradation by nucleases, facilitates their uptake by dendritic cells, and targets these nucleic acids to the endosomal compartment in which they are recognized by TLR7. In these effects, the nanoparticles are superior to the conventional transfection reagents lipofectamine, polyethylenimine, and DOTAP. In vivo, the delivery of TLR7-activating RNA oligonucleotides by gelatin nanoparticles triggers antigen-specific CD8+ T-cell and antibody responses. Indeed, immunization with RNA-loaded nanoparticles leads to an efficient antitumoral immune response in two different mouse tumor models. Thus, gelatin-based nanoparticles represent a novel delivery system for immunostimulatory RNA oligonucleotides that is both effective and nontoxic.

A Nebulized Gelatin Nanoparticle-Based CpG Formulation is Effective in Immunotherapy of Allergic Horses

ABSTRACTPurposeIn the recent years, nanotechnology has boosted the development of potential drug delivery systems and material engineering on nanoscale basis in order to increase drug specificity and reduce side effects. A potential delivery system for immunostimulating agents such as Cytosine-Phosphate-Guanine-Oligodeoxynucleotides (CpG-ODN) needs to be developed to maximize the efficacy of immunotherapy against hypersensitivity. In this study, an aerosol formulation of biodegradable, biocompatible and nontoxic gelatin nanoparticle-bound CpG-ODN 2216 was used to treat equine recurrent airway obstruction in a clinical study.MethodsBronchoalveolar lavage fluid was obtained from healthy and allergic horses to quantify Th1/Th2 cytokine levels before and after inhalation regimen. Full clinical examinations were performed to evaluate the therapeutic potential of this nebulized gelatin nanoparticle-based CpG formulation.ResultsMost remarkable was that regulatory anti-inflammatory and anti-allergic cytokine IL-10 expression was significantly triggered by five consecutive inhalations. Thorough assessment of clinical parameters following nanoparticle treatment indicated a partial remission of the allergic condition.ConclusionThus this study, for the first time, showed effectiveness of colloidal nanocarrier-mediated immunotherapy in food-producing animals with potential future applicability to other species including humans.

Transglutaminase: new insights into gelatin nanoparticle cross-linking.

Gelatin nanoparticles (GNPs) have demonstrated to be beneficial as a biodegradable and biocompatible delivery system. So far, nanoparticles prepared by the two-step desolvation technique were subsequently cross-linked by glutaraldehyde to guarantee storage stability. Although in vivo and in vitro toxicological studies have not revealed any glutaraldehyde related undesired effects, an alternative to chemical cross-linking could ease future clinical use in humans. Therefore, the recombinant enzyme microbial transglutaminase was used to examine its cross-linking abilities in nanoparticle production. Various process parameters, such as incubation time, temperature, medium, pH and the particle purification were evaluated regarding their impact on particle size and its distribution. Cross-linking reactions were best at 25°C using an ion-free solvent at a neutral pH and have been terminated after 12u2009h. Preliminary storage stability testing indicated adequate consistency of particle size and particle distribution making transglutaminase a potential candidate for glutaraldehyde substitution in future GNP production.

Immunostimulation of bronchoalveolar lavage cells from recurrent airway obstruction-affected horses by different CpG-classes bound to gelatin nanoparticles

Recurrent airway obstruction (RAO) in horses has become a common problem in stabled horses in industrialized countries and deserves new therapeutic strategies. CpG-oligodeoxynucleotides (CpG-ODNs) were developed as effective immunostimulating agents to induce a Th2/Th1 shift. These agents showed a beneficial therapeutic effect in allergic diseases with predominant Th2 immunoresponse. CpG-ODN delivery by gelatin nanoparticles (GNPs) resulted in enhanced cellular uptake in murine and human in vitro studies and was a starting point for the present trial. The aim of this study was to identify an optimal stimulating CpG motif in horses with regard to species specificity on equine bronchoalveolar lavage (BAL) cells, in terms of a possible specific immunomodulation effect (Th2/Th1 shift) by used CpG-ODN. Accordingly, GNPs were evaluated as a delivery system to improve CpG-ODN immunostimulation in equine BAL cells. BAL fluid (BALF) was obtained from seven horses with moderate RAO and from four healthy horses and was subsequently incubated with five different CpG-ODN sequences (from A-, B- and C-class) and one ODN without any CpG motif. Release of three key cytokines (IL-4, IL-10 and IFN-γ) was quantified by ELISA to detect an allergy mediated Th2 immunoresponse (IL-4) as well as a proinflammatory Th1 response (IFN-γ). Due to its specific anti-inflammatory and anti-allergic effects, IL-10 was considered as a beneficial agent in pathophysiology of RAO. Results showed a significant upregulation of IL-10 and IFN-γ on the one hand and a downregulation of IL-4 on the other hand in RAO affected horses. Cell cultures from healthy horses had a significantly stronger response in cytokine release to all the applied stimuli in contrast to RAO derived cells. Comparing all five CpG sequences, A-class 2216 significantly showed the highest immunomodulatory effects on equine BALF cells and, hence, was chosen for follow-up preliminary clinical studies.

Nanoparticulate CpG Immunotherapy in RAO- Affected Horses: Phase I and IIa Study

Background Recurrent airway obstruction (RAO), an asthma‐like disease, is 1 of the most common allergic diseases in horses in the northern hemisphere. Hypersensitivity reactions to environmental antigens cause an allergic inflammatory response in the equine airways. Cytosine‐phosphate‐guanosine‐oligodeoxynucleotides (CpG‐ODN) are known to direct the immune system toward a Th1‐pathway, and away from the pro‐allergic Th2‐line (Th2/Th1‐shift). Gelatin nanoparticles (GNPs) are biocompatible and biodegradable immunological inert drug delivery systems that protect CpG‐ODN against nuclease degeneration. Preliminary studies on the inhalation of GNP‐bound CpG‐ODN in RAO‐affected horses have shown promising results. Objectives The aim of this study was to evaluate the clinical and immunological effects of GNP‐bound CpG‐ODN in a double‐blinded, placebo‐controlled, prospective, randomized clinical trial and to verify a sustained effect post‐treatment. Animals and Methods Twenty‐four RAO‐affected horses received 1 inhalation every 2 days for 5 consecutive administrations. Horses were examined for clinical, endoscopic, cytological, and blood biochemical variables before the inhalation regimen (I), immediately afterwards (II), and 4 weeks post‐treatment (III). Results At time points I and II, administration of treatment rather than placebo corresponded to a statistically significant decrease in respiratory effort, nasal discharge, tracheal secretion, and viscosity, AaDO 2 and neutrophil percentage, and an increase in arterial oxygen pressure. Conclusion and Clinical Importance Administration of a GNP‐bound CpG‐ODN formulation caused a potent and persistent effect on allergic and inflammatory‐induced clinical variables in RAO‐affected horses. This treatment, therefore, provides an innovative, promising, and well‐tolerated strategy beyond conventional symptomatic long‐term therapy and could serve as a model for asthma treatment in humans.

Towards an inhalative in vivo application of immunomodulating gelatin nanoparticles in horse-related preformulation studies

Delivering active ingredients using biocompatible and biodegradable carriers such as gelatin nanoparticles (GNPs) to the lung constitutes a promising non-invasive route of administration. However, the pulmonary delivery of nanoparticle-based immunotherapy is still a field that requires more clarification. In this study, GNPs loaded with cytosine-phosphate-guanine oligodeoxynucleotides (CpG-ODN)-loaded and plain GNPs were aerosolised either by a conventional pressured metered dose inhaler (pMDI) or by active or passive vibrating-mesh (VM) nebulisers. GNP sizes after nebulisation by active and passive VM nebulisers were 248.2u2009±u20097.34 and 222.3u2009±u20091.42u2009nm, respectively. GNP concentrations after aerosolisation were found consistent and second-stage particle deposition in an impinger was up to 65.68u2009±u200911.2% of the nebulised dose. VM nebulisers produced high fine particle fractions, while pMDIs did not. Nebulised CpG-ODN-loaded GNPs remained capable to stimulate IL-10 release (225.2u2009±u200956.3u2009pg/ml) in vitro from equine alveolar lymphocytes. Thus, a novel system for pulmonary GNP-mediated immunotherapy in vivo was established.

Ultrasonic resonator technology as a new quality control method evaluating gelatin nanoparticles.

Nanomedicine is a quickly evolving field where more and more possible applications become evident and start entering clinical trials or even the market. However, the analytic methods are not always able to keep pace with the new formulations’ demands. One example of a promising medical implementation is oligodeoxynucleotide (ODN) delivery by gelatin nanoparticles (GNPs). Currently, quality control is dependent on either some time consuming or destructive spectrometric, chromatographic or electrophoretic methods. A possible enlargement of the portfolio by Ultrasonic Resonator Technology (URT) is investigated here by subjecting plain GNPs in various sizes and concentrations as well as ODN-loaded GNPs to URT analysis. If calibrated by photon correlation spectroscopy (PCS) and other spectroscopy methods for each single nanoparticle system parameter, URT is an efficient and non-destructive technique and serves as a broad characterization method. URT is emphasized to play a possible future part in the size, concentration and ODN loading monitoring, e.g. of gelatin nanoparticles in the course of formulation development.

Is there a tacit acceptance of student samples in marketing and management research

The evaluation criteria for most marketing and management journals underline the importance of student samples characteristics and how well they represent the population being studied. However, the predominance of student samples in empirical marketing and management research is sufficient proof of the divergence between theoretical requirements and practical implementation. Despite the theoretical and empirical objections, several authors claim that there is a noticeable tacit acceptance of student samples, even in top research societies. However, generalisations are only feasible if the replication of research is carried out with non-student subjects. This paper analyses the status quo of the usage of student samples in the most reputable marketing and management research journals. In doing so, we want to resume the discussion on student sampling, which has been dormant during the last few years. Our results provide some evidence that top-tier journals still rely strongly on student samples.