Inflammasome-activating nanoparticles as modular systems for optimizing vaccine efficacy

Preclinical Development of a Romidepsin Nanoparticle Demonstrates Superior Tolerability and Efficacy in Models of Human T-Cell Lymphoma and Large Granular Lymphocyte Leukemia

Histone deacetylase (HDAC) inhibitors are a widely recognized and valued treatment option for patients with relapsed or refractory peripheral T cell lymphomas (PTCL). Romidepsin is a relatively selective Class I HDAC inhibitor originally approved for patients with relapsed or refractory (R/R) cutaneous T cell lymphoma (CTCL) and subsequently R/R PTCL. Unfortunately, the FDA approval of romidepsin for R/R PTCL was withdrawn due to a negative Phase 4 post-marketing requirement (PMR), diminishing further the treatment options for patients with PTCL. Herein we describe the development of a first-in-class polymer nanoparticle of romidepsin (Nanoromidepsin) using an innovative amphiphilic di-block copolymer-based nanochemistry platform. Nanoromidepsin exhibited superior pharmacologic disposition, with improved tolerability and safety in murine models of T-cell lymphoma. Nanoromidepsin also exhibited superior anti-tumor efficacy in multiple models including in vitro T cell lymphoma (TCL) cell lines, ex vivo LGL leukemia primary patient samples, and murine TCL xenografts. Nanoromidepsin demonstrated greater accumulation in tumors and a statistically significant improvement in overall survival (OS) compared to romidepsin in murine xenograft models. These findings collectively justify the clinical development of Nanoromidepsin in patients with T-cell malignancies.

Nanomedicine - Immune System Interactions: Limitations and Opportunities for the Treatment of Cancer

Nanoparticles interact with immune cells in many different ways. These interactions are crucially important for determining nanoparticles' ability to be used for cancer therapy. Traditionally, strategies such as PEGylation have been employed to reduce (the kinetics of) nanoparticle uptake by immune cells, to endow them with long circulation properties, and to enable them to exploit the Enhanced Permeability and Retention (EPR) effect to accumulate in tumors. More recently, with immunotherapy becoming an increasingly important cornerstone in the clinical management of cancer, ever more research efforts in academia and industry are focusing on specifically targeting immune cells with nanoparticles. In this chapter, we describe the barriers and opportunities of immune cell targeting with nanoparticles, and we discuss how nanoparticle-based drug delivery to specific immune cell populations in tumors as well as in secondary myeloid and lymphoid organs (such as bone marrow, lymph nodes, and spleen) can be leveraged to boost the efficacy of cancer immunotherapy.

Nano-delivery systems as a promising therapeutic potential for epilepsy: Current status and future perspectives

Epilepsy is a common chronic neurological disorder caused by aberrant neuronal electrical activity. Antiseizure medications (ASMs) are the first line of treatment for people with epilepsy (PWE). However, their effectiveness may be limited by their inability to cross the blood-brain barrier (BBB), among many other potential underpinnings for drug resistance in epilepsy. Therefore, there is a need to overcome this issue and, hopefully, improve the effectiveness of ASMs. Recently, synthetic nanoparticle-based drug delivery systems have received attention for improving the effectiveness of ASMs due to their ability to cross the BBB. Furthermore, exosomes have emerged as a promising generation of drug delivery systems because of their potential benefits over synthetic nanoparticles. In this narrative review, we focus on various synthetic nanoparticles that have been studied to deliver ASMs. Furthermore, the benefits and limitations of each nano-delivery system have been discussed. Finally, we discuss exosomes as potentially promising delivery tools for treating epilepsy.

Current Progress and Challenges in the Study of Adjuvants for Oral Vaccines

Over the past 20 years, a variety of potential adjuvants have been studied to enhance the effect of oral vaccines in the intestinal mucosal immune system; however, no licensed adjuvant for clinical application in oral vaccines is available. In this review, we systematically updated the research progress of oral vaccine adjuvants over the past 2 decades, including biogenic adjuvants, non-biogenic adjuvants, and their multi-type composite adjuvant materials, and introduced their immune mechanisms of adjuvanticity, aiming at providing theoretical basis for developing feasible and effective adjuvants for oral vaccines. Based on these insights, we briefly discussed the challenges in the development of oral vaccine adjuvants and prospects for their future development.

Immunogenicity and protective efficacy of an inactivated Newcastle disease virus vaccine encapsulated in poly-(lactic-co-glycolic acid) nanoparticles

An immunization experiment was conducted in specific pathogen-free chickens with the inactivated Newcastle disease virus (NDV) vaccine encapsulated in the poly-(lactic-co-glycolic) acid (PLGA) nanoparticles (NP) to evaluate its immunogenicity and protective efficacy. The NDV vaccine was prepared by inactivating one virulent Indian strain of NDV belonging to Genotype VII by using beta-propiolactone. PLGA nanoparticles encapsulating inactivated NDV were prepared by the solvent evaporation method. Scanning electron microscopy and zeta sizer analysis revealed that the (PLGA+NDV) NP were spherical, with an average size of 300 nm, having a zeta potential of -6 mV. The encapsulation efficiency and loading efficiency were 72% and 2.4%, respectively. On immunization trial in chicken, the (PLGA+NDV) NP induced significantly (P < 0.0001) higher levels of HI and IgY antibodies with the peak HI titer of 2⁸ and higher expression of IL-4 mRNA. The consistency of higher antibody levels suggests slow and pulsatile release of the antigens from the (PLGA+NDV) NP. The nano-NDV vaccine also induced cell mediated immunity with higher expression of IFN-γ indicating strong Th1 mediated immune responses in contrast to the commercial oil adjuvanted inactivated NDV vaccine. Further, the (PLGA+NDV) NP afforded 100% protection against the virulent NDV challenge. Our results suggested that PLGA NP have adjuvant potential on induction of humoral as well as Th1 biased cell mediated immune responses and also enhanced protective efficacy of the inactivated NDV vaccine. This study provides an insight for development of PLGA NP based inactivated NDV vaccine using the same genotype circulating in the field as well as for other avian diseases at exigencies.

Nanoreporter for Real-Time Monitoring of Inflammasome Activity and Targeted Therapy

Inflammasome activation is associated with a myriad of inflammatory diseases. However, existing methods provides a limited understanding of spatiotemporal kinetics of inflammasome activation, with restricted scope for early detection of associated treatment efficacy. This limitation offers an opportunity for the development of biocompatible in-vivo inflammasome monitoring tools with translational prospects. To achieve this, they report developing a pair of lipid-based nanoparticle systems, a reporter nanoparticle consisting of a caspase-1 activatable probe alone, and a theranostic nanoparticle combining the probe with an inflammasome-inhibiting drug. This biocompatible platform enhances the probe's residence time in circulation by preventing its opsonization and allowing its sustained release over time. Their results demonstrate the specificity of reporter nanoparticles towards caspase-1 activity and provides early-on monitoring of inflammasome activation both in-vitro as well as in-vivo. Additionally, the delivery of disulfiram, an inflammasome-inhibiting drug, along with reporter probe using theranostic nanoparticles enables real-time tracking of treatment efficacy in the gouty-arthritis inflammatory model. In summary, they report an unparalleled pair of the inflammasome-associated reporter and theranostic platforms suited not only for diagnostic applications but can also detect inflammasome-targeted treatment efficiency in real-time. These findings establish two novel, sensitive nanotools for non-invasive evaluation of inflammasome-targeted immunotherapy.

Nanomaterials and Their Impact on the Immune System

Nanomaterials have been the focus of intensive development and research in the medical and industrial sectors over the past several decades. Some studies have found that these compounds can have a detrimental impact on living organisms, including their cellular components. Despite the obvious advantages of using nanomaterials in a wide range of applications, there is sometimes skepticism caused by the lack of substantial proof that evaluates potential toxicities. The interactions of nanoparticles (NPs) with cells of the immune system and their biomolecule pathways are an area of interest for researchers. It is possible to modify NPs so that they are not recognized by the immune system or so that they suppress or stimulate the immune system in a targeted manner. In this review, we look at the literature on nanomaterials for immunostimulation and immunosuppression and their impact on how changing the physicochemical features of the particles could alter their interactions with immune cells for the better or for the worse (immunotoxicity). We also look into whether the NPs have a unique or unexpected (but desired) effect on the immune system, and whether the surface grafting of polymers or surface coatings makes stealth nanomaterials that the immune system cannot find and get rid of.

Biological Features of Nanoparticles: Protein Corona Formation and Interaction with the Immune System

Nanoparticles (NPs) are versatile candidates for nanomedical applications due to their unique physicochemical properties. However, their clinical applicability is hindered by their undesirable recognition by the immune system and the consequent immunotoxicity, as well as their rapid clearance in vivo. After injection, NPs are usually covered with layers of proteins, called protein coronas (PCs), which alter their identity, biodistribution, half-life, and efficacy. Therefore, the characterization of the PC is for in predicting the fate of NPs in vivo. The aim of this review was to summarize the state of the art regarding the intrinsic factors closely related to the NP structure, and extrinsic factors that govern PC formation in vitro. In addition, well-known opsonins, including complement, immunoglobulins, fibrinogen, and dysopsonins, such as histidine-rich glycoprotein, apolipoproteins, and albumin, are described in relation to their role in NP detection by immune cells. Particular emphasis is placed on their role in mediating the interaction of NPs with innate and adaptive immune cells. Finally, strategies to reduce PC formation are discussed in detail.

Biopolymer Nanoparticles for Nose-to-Brain Drug Delivery: A New Promising Approach for the Treatment of Neurological Diseases

Diseases affecting the central nervous system (CNS) are among the most disabling and the most difficult to cure due to the presence of the blood–brain barrier (BBB) which represents an impediment from a therapeutic and diagnostic point of view as it limits the entry of most drugs. The use of biocompatible polymer nanoparticles (NPs) as vehicles for targeted drug delivery to the brain arouses increasing interest. However, the route of administration of these vectors remains critical as the drug must be delivered without being degraded to achieve a therapeutic effect. An innovative approach for the administration of drugs to the brain using polymeric carriers is represented by the nose-to-brain (NtB) route which involves the administration of the therapeutic molecule through the neuro-olfactory epithelium of the nasal mucosa. Nasal administration is a non-invasive approach that allows the rapid transport of the drug directly to the brain and minimizes its systemic exposure. To date, many studies involve the use of polymer NPs for the NtB transport of drugs to the brain for the treatment of a whole series of disabling neurological diseases for which, as of today, there is no cure. In this review, various types of biodegradable polymer NPs for drug delivery to the brain through the NtB route are discussed and particular attention is devoted to the treatment of neurological diseases such as Glioblastoma and neurodegenerative diseases.

The Influence of Nanoparticle on Vaccine Responses against Bacterial Infection

Nowadays, nanovaccine is considered as an evolving method in the field of vaccination to induce immunity in the human body against various diseases, including bacterial or viral diseases as well as virulent tumors. Nanovaccines are more efficient than traditional vaccines since they could potentially induce both humoral and cellular immune reactions. Various studies have shown that nanoparticles with multiple compounds have been designed as delivery systems or as adjuvants for vaccines. Nanoparticles could function as a drug delivery tool, as an adjuvant to promote antigen processing, and as an immune modulator to induce immune responses. These nanoparticles generate immune responses through activating immune cells as well as through the production of antibody responses. Design engineering of nanoparticles (NPs) used to produce nanovaccines to induce immunity in the human body needs comprehensive information about the ways they interact with the component of immune system. Challenges remain due to the lack of sufficient and comprehensive information about the nanoparticles' mode of action. Several studies have described the interactions between various classes of nanoparticles and the immune system in the field of prevention of bacterial infections. The results of some studies conducted in recent years on the interaction between nanoparticles and biosystems have considerably affected the methods used to design nanoparticles for medical applications. In this review, NPs’ characteristics influencing their interplay with the immune system were discussed in vivo. The information obtained could lead to the development of strategies for rationalizing the design of nanovaccines in order to achieve optimum induction of immune response.

Targeting NLRP3-Mediated Neuroinflammation in Alzheimer’s Disease Treatment

Alzheimer’s disease (AD) is the most common cause of dementia in the general population and, to date, constitutes a major therapeutic challenge. In the pathogenesis of AD, aggregates of amyloid β (Aβ) and neurofibrillary tangles (NFTs) containing Tau-microtubule-associated protein (tau) are known to trigger a neuroinflammatory response with subsequent formation of an inflammasome. In particular, the NOD-like receptor pyrin domain-containing 3 (NLRP3) inflammasome is thought to play a crucial role in AD-related pathology. While the mechanisms for NLRP3 activation are not fully understood, it has been demonstrated that, after detection of protein aggregates, NLRP3 induces pro-inflammatory cytokines, such as interleukin 18 (IL-18) or interleukin 1β (IL-1β), that further potentiate AD progression. Specific inhibitors of NLRP3 that exhibit various mechanisms to attenuate the activity of NLRP3 have been tested in in vivo studies and have yielded promising results, as shown by the reduced level of tau and Aβ aggregates and diminished cognitive impairment. Herein, we would like to summarize the current state of knowledge on NLRP3 inflammasome priming, activation, and its actual role in AD pathogenesis, and to characterize the NLRP3 inhibitors that have been studied most and their impact on AD-related pathology.

Scientific premise for the involvement of neutrophil extracellular traps (NETs) in vaccine-induced thrombotic thrombocytopenia (VITT)

Following on from the devastating spread of COVID-19, a major global priority has been the production, procurement, and distribution of effective vaccines to ensure that the global pandemic reaches an end. However, concerns were raised about worrying side effects, particularly the occurrence of thrombosis and thrombocytopenia after administration of the Oxford/AstraZeneca and Johnson & Johnson's Janssen COVID-19 vaccine, in a phenomenon being termed vaccine-induced thrombotic thrombocytopenia (VITT). Similar to heparin-induced thrombocytopenia (HIT), this condition has been associated with the development of anti-platelet factor 4 antibodies, purportedly leading to neutrophil-platelet aggregate formation. Although thrombosis has also been a common association with COVID-19, the precise molecular mechanisms governing its occurrence are yet to be established. Recently, increasing evidence highlights the NLRP3 (NOD-like, leucine-rich repeat domains, and pyrin domain-containing protein) inflammasome complex along with IL-1β and effete neutrophils producing neutrophil extracellular traps (NETs) through NETosis. Herein, we propose and discuss that perhaps the incidence of VITT may be due to inflammatory reactions mediated via IL-1β/NLRP3 inflammasome activation and consequent overproduction of NETs, where similar autoimmune mechanisms are observed in HIT. We also discuss avenues by which such modalities could be treated to prevent the occurrence of adverse events and ensure vaccine rollouts remain safe and on target to end the current pandemic.

Circulating extracellular vesicle microRNAs associated with adverse reactions, proinflammatory cytokine, and antibody production after COVID-19 vaccination

mRNA-based vaccines have been used globally to eradicate the coronavirus-disease 2019 (COVID-19) pandemic. Vaccine efficacy and adverse reactions depend on immune responses, such as proinflammatory cytokine production and lymphocyte activation. We conducted a prospective cohort study to investigate relationships among specific antibody titers, adverse reactions, proinflammatory cytokine production, and immune-regulatory microRNA (miRNA) levels in serum extracellular vesicles (EVs) after COVID-19 vaccination (BNT162b2). Local adverse reactions after the second dose, such as local pain and swelling, were less correlated with those of systemic symptoms, such as fever and muscle pain, whereas serum TNF-α levels were associated with systemic adverse reactions and with specific antibody titers. Interestingly, EV miR-92a-2-5p levels in sera were negatively correlated with degrees of adverse reactions, and EV miR-148a levels were associated with specific antibody titers. Our data suggest a potential of circulating EV miRNAs as biomarkers for vaccine efficacy and adverse reactions.

Mechanisms of immune response to inorganic nanoparticles and their degradation products

Careful assessment of the biological fate and immune response of inorganic nanoparticles is crucial for use of such carriers in drug delivery and other biomedical applications. Many studies have elucidated the cellular and molecular mechanisms of the interaction of inorganic nanoparticles with the components of the immune system. The biodegradation and dissolution of inorganic nanoparticles can influence their ensuing immune response. While the immunological properties of inorganic nanoparticles as a function of their physicochemical properties have been investigated in detail, little attention has been paid to the immune adverse effects towards the degradation products of these nanoparticles. To fill this gap, we herein summarize the cellular mechanisms of immune response to inorganic nanoparticles and their degradation products with specific focus on immune cells. We also accentuate the importance of designing new methods and instruments for the in situ characterization of inorganic nanoparticles in order to assess their safety as a result of degradation. This review further sheds light on factors that need to be considered in the design of safe and effective inorganic nanoparticles for use in delivery of bioactive and imaging agents.

COVID-19 Vaccine-Related Thrombosis: A Systematic Review and Exploratory Analysis

Introduction

The World Health Organization declared the coronavirus disease 2019 (COVID-19) pandemic on March 11, 2020. Two vaccine types were developed using two different technologies: viral vectors and mRNA. Thrombosis is one of the most severe and atypical adverse effects of vaccines. This study aimed to analyze published cases of thrombosis after COVID-19 vaccinations to identify patients' features, potential pathophysiological mechanisms, timing of appearance of the adverse events, and other critical issues.

Materials and Methods

We performed a systematic electronic search of scientific articles regarding COVID-19 vaccine-related thrombosis and its complications on the PubMed (MEDLINE) database and through manual searches. We selected 10 out of 50 articles from February 1 to May 5, 2021 and performed a descriptive analysis of the adverse events caused by the mRNA-based Pfizer and Moderna vaccines and the adenovirus-based AstraZeneca vaccine.

Results

In the articles on the Pfizer and Moderna vaccines, the sample consisted of three male patients with age heterogeneity. The time from vaccination to admission was ≤3 days in all cases; all patients presented signs of petechiae/purpura at admission, with a low platelet count. In the studies on the AstraZeneca vaccine, the sample consisted of 58 individuals with a high age heterogeneity and a high female prevalence. Symptoms appeared around the ninth day, and headache was the most common symptom. The platelet count was below the lower limit of the normal range. All patients except one were positive for PF4 antibodies. The cerebral venous sinus was the most affected site. Death was the most prevalent outcome in all studies, except for one study in which most of the patients remained alive.

Discussion

Vaccine-induced thrombotic thrombocytopenia (VITT) is an unknown nosological phenomenon secondary to inoculation with the COVID-19 vaccine. Several hypotheses have been formulated regarding its physiopathological mechanism. Recent studies have assumed a mechanism that is assimilable to heparin-induced thrombocytopenia, with protagonist antibodies against the PF4-polyanion complex. Viral DNA has a negative charge and can bind to PF4, causing VITT. New experimental studies have assumed that thrombosis is related to a soluble adenoviral protein spike variant, originating from splicing events, which cause important endothelial inflammatory events, and binding to endothelial cells expressing ACE2.

Conclusion

Further studies are needed to better identify VITT's pathophysiological mechanisms and genetic, demographic, or clinical predisposition of high-risk patients, to investigate the correlation of VITT with the different vaccine types, and to test the significance of the findings.

Enhancing therapeutic performance of personalized cancer vaccine via delivery vectors

In recent years, personalized cancer vaccines have gained increasing attention as emerging immunotherapies with the capability to overcome interindividual differences and show great benefits for individual patients in the clinic due to the highly tailored vaccine formulations. A large number of materials have been studied as delivery vectors to enhance the therapeutic performance of personalized cancer vaccines, including artificial materials, engineered microorganisms, cells and cell derivatives. These delivery vectors with distinct features are employed to change antigen biodistributions and to facilitate antigen uptake, processing and presentation, improving the strength, velocity, and duration of the immune response when delivered by different strategies. Here, we provide an overview of personalized cancer vaccine delivery vectors, describing their materials, physicochemical properties, delivery strategies and challenges for clinical transformation.

Core Hydrophobicity of Supramolecular Nanoparticles Induces NLRP3 Inflammasome Activation

Designer nanomaterials capable of delivering immunomodulators to specific immune cells have been extensively studied. However, emerging evidence suggests that several of these nanomaterials can nonspecifically activate NLRP3 inflammasomes, an intracellular multiprotein complex controlling various immune cell functions, leading to undesirable effects. To understand what nanoparticle attributes activate inflammasomes, we designed a multiparametric polymer supramolecular nanoparticle system to modulate various surface and core nanoparticle-associated molecular patterns (NAMPs), one at a time. We also investigated several underlying signaling pathways, including lysosomal rupture-cathepsin B maturation and calcium flux-mitochondrial ROS production, to gain mechanistic insights into NAMPs-mediated inflammasome activation. Here, we report that out of the four NAMPs tested, core hydrophobicity strongly activates and positively correlates with the NLRP3 assembly compared to surface charge, core rigidity, and surface hydrophobicity. Moreover, we demonstrate different signaling inclinations and kinetics followed by differential core hydrophobicity patterns with the most hydrophobic ones exhibiting both lysosomal rupture and calcium influx early on. Altogether, this study will help design the next generation of polymeric nanomaterials for specific regulation of inflammasome activation, aiding efficient immunotherapy and vaccine delivery.

Effect of SARS-CoV-2 Mutations on the Efficacy of Antibody Therapy and Response to Vaccines

SARS-CoV-2 causes severe acute respiratory syndrome, which has led to significant morbidity and mortality around the world. Since its emergence, extensive prophylactic and therapeutic countermeasures have been employed to successfully prevent the spread of COVID-19. Extensive work has been undertaken on using monoclonal antibody therapies, mass vaccination programs, and antiviral drugs to prevent and treat COVID-19. However, since antiviral drugs could take years to become widely available, immunotherapy and vaccines currently appear to be the most feasible option. In December 2020, the first vaccine against SARS-CoV-2 was approved by the World Health Organization (WHO) and, subsequently, many other vaccines were approved for use by different international regulators in different countries. Most monoclonal antibodies (mAbs) and vaccines target the SARS-CoV-2 surface spike (S) protein. Recently, mutant (or variant) SARS-CoV-2 strains with increased infectivity and virulence that evade protective host antibodies present either due to infection, antibody therapy, or vaccine administration have emerged. In this manuscript, we discuss the different monoclonal antibody and vaccine therapies available against COVID-19 and how the efficacy of these therapies is affected by the emergence of variants of SARS-CoV-2. We also discuss strategies that might help society cope with variants that could neutralize the effects of immunotherapy and escape the protective immunity conferred by vaccines.

Synopsis on Pharmotechnological Approaches in Diagnostic to Management Strategies in Fighting Against COVID-19

Nanoparticles (NPs) are projected to play a significant role in fighting against coronavirus disease (COVID-19). The various properties of NPs like magnetic and optical can be exploited to build diagnostic test kits. The unembellished morphological and physiochemical resemblances of SARS-CoV-2 with synthetic NPs make them a potent tool for mediation. Nanoparticles can be analytically functionalized with different proteins, polymers, and functional groups to perform specific inhibitory functions while also serving as delivery vehicles . Moreover, NPs can also be employed to prepare broad-spectrum respiratory drugs and vaccines that can guard seasonal flu and prepare the human race for the pandemic in the future. The present review outlines the role of NPs in detection, diagnostic and therapeutic against members of the coronavirus family. We emphasize nanomaterial-based approaches to address coronaviruses in general and SARS-CoV-2 in particular. We discuss NPs based detection systems like graphene (G-FET), biosensors, and plasmonic photothermal associated sensors. Inorganic, organic virus-like & self-assembly protein (VLP), and photodynamic inactivation of SARS-CoV-2 are also presented as therapeutic approaches exploiting NPs.

Feasibility of chitosan-based nanoparticles approach for intranasal immunisation of live attenuated Japanese encephalitis vaccine

Intranasal (IN) administration, a non-invasive route, is explored to overcome the limitations of conventional subcutaneous (SC) injection for Japanese encephalitis (JE) immunisation. Mucoadhesive nanoparticles (NPs) are recognised for the benefits they offer via IN delivery, such as extended retention time of the vaccine on the mucosa. The purpose of this study was to evaluate immunisation effect of live attenuated Japanese encephalitis-chimeric virus vaccine (JE-CV)-loaded mucoadhesive NPs based on chitosan (CS) or chitosan maleimide (CM), a novel mucoadhesive polymer, via the IN route to improve the mucosal immunisation against JE. The results revealed that IN immunisation stimulated seroprotection following PRNT₅₀ evaluation. Moreover, compared with SC immunisation, IN immunisation in mice provided a higher sIgA level, leading to improved mucosal immune response. In addition, chitosan-based NPs showed an adjuvant effect on the IN vaccine due to their mucoadhesive and antigen-uptaken properties. CM NPs successfully induced sIgA. In contrast, SC JE-CV immunisation induced negligible mucosal immunity. These immunological advantages revealed that JE-CV-loaded mucoadhesive NPs are a promising approach for IN vaccination as an alternative route for JE protection due to the stimulatory effects on both mucosal and systemic immune responses.

Sesquiterpene-Loaded Co-Polymer Hybrid Nanoparticle Effects on Human Mast Cell Surface Receptor Expression, Granule Contents, and Degranulation

Biodegradable polymeric nanoparticles (NPs) such as poly(lactic-co-glycolic acid) (PLGA) and polyvinyl alcohol (PVA) have been used as drug delivery systems for natural and synthetic compounds and are designed to control the loading and release of biodegradable materials to target cells, tissues, and organs. Eremophilane-type sesquiterpenes have anti-inflammatory properties but are lipophilic, cytotoxic, and not biocompatible with many cells. To determine whether biodegradable PLGA/PVA could improve the biocompatibility of sesquiterpenes, sesquiterpene-loaded NPs were synthesized and their effects on human mast cells (LAD2), the major effector cells of allergic inflammation, were determined. NPs composed of PLGA/PVA and two types of sesquiterpenes (fukinone, PLGA/PVA-21 and 10βH-8α,12-epidioxyeremophil-7(11)-en-8β-ol, PLGA/PVA-22) were produced using a microfluidic synthesis method. The NPs’ size distribution and morphology were evaluated by dynamic light scattering and cryogenic transmission electron microscopy (TEM). PLGA/PVA-21 and PLGA/PVA-22 were 60 to 70 nm and were readily internalized by LAD2 as shown by flow cytometry, fluorescence microscopy, and TEM. While unencapsulated sesquiterpenes decreased LAD2 cell viability by 20%, PLGA/PVA-21 and PLGA/PVA-22 did not alter LAD2 viability, showing that encapsulation improved the biocompatibility of the sesquiterpenes. PLGA/PVA-21 and PLGA/PVA-22 decreased the expression of genes encoding the subunits of the high affinity immunoglobulin E receptor (FcεR1α, FcεR1β, FcεR1γ) and the stem cell factor receptor (Kit,), suggesting that hybrid NPs could alter mast cell responses to antigens and shift their maturation. Similarly, PLGA/PVA-21 and PLGA/PVA-22 inhibited tryptase expression but had no effect on chymase expression, thereby promoting a shift to the tryptase-positive phenotype (MC_T). Lastly, PLGA/PVA-21 and PLGA/PVA-22 inhibited mast cell degranulation when the LAD2 cells were activated by IgE crosslinking and FcεRI. Overall, our results suggest that PLGA/PVA-21 and PLGA/PVA-22 alter human mast cell phenotype and activation without modifying viability, making them a more biocompatible approach than treating cells with sesquiterpenes alone.

Novel approaches for vaccine development

Vaccines are critical tools for maintaining global health. Traditional vaccine technologies have been used across a wide range of bacterial and viral pathogens, yet there are a number of examples where they have not been successful, such as for persistent infections, rapidly evolving pathogens with high sequence variability, complex viral antigens, and emerging pathogens. Novel technologies such as nucleic acid and viral vector vaccines offer the potential to revolutionize vaccine development as they are well-suited to address existing technology limitations. In this review, we discuss the current state of RNA vaccines, recombinant adenovirus vector-based vaccines, and advances from biomaterials and engineering that address these important public health challenges.

Nanotechnology against the novel coronavirus (severe acute respiratory syndrome coronavirus 2): diagnosis, treatment, therapy and future perspectives

COVID-19, as an emerging infectious disease, has caused significant mortality and morbidity along with socioeconomic impact. No effective treatment or vaccine has been approved yet for this pandemic disease. Cutting-edge tools, especially nanotechnology, should be strongly considered to tackle this virus. This review aims to propose several strategies to design and fabricate effective diagnostic and therapeutic agents against COVID-19 by the aid of nanotechnology. Polymeric, inorganic self-assembling materials and peptide-based nanoparticles are promising tools for battling COVID-19 as well as its rapid diagnosis. This review summarizes all of the exciting advances nanomaterials are making toward COVID-19 prevention, diagnosis and therapy.

Enhancing Immunity with Nanomedicine: Employing Nanoparticles to Harness the Immune System

The failure of immune responses to vaccines and dysfunctional immune responses to viral infection, tumor development, or neoantigens lead to chronic viral infection, tumor progression, or incomplete immune protection after vaccination. Thus, strategies to boost host immunity are a topic of intense research and development. Engineered nanoparticles (NPs) possess immunological properties and can be modified to promote improved local immune responses. Nanoparticle-based approaches have been employed to enhance vaccine efficacy and host immune responses to viral and tumor antigens, with impressive results. In this Perspective, we present an overview of studies, such as the one reported by Alam et al. in this issue of ACS Nano, in which virus-like particles have been employed to enhance immunity. We review the cellular cornerstones of effective immunity and discuss how NPs can harness these interactions to overcome the current obstacles in vaccinology and oncology. We also discuss the barriers to effective NP-mediated immune priming including (1) NP delivery to the site of interest, (2) the quality of response elicited, and (3) the potential of the response to overcome immune escape. Through this Perspective, we aim to highlight the value of nanomedicine not only in delivering therapies but also in coordinating the enhancement of host immune responses. We provide a forward-looking outlook for future NP-based approaches and how they could be tailored to promote this outcome.

Effective and Safe Stimulation of Humoral and Cell-Mediated Immunity by Intradermal Immunization with a Cyclic Dinucleotide/Nanoparticle Combination Adjuvant

Intradermal (ID) immunization is an attractive route of vaccination because it targets tissue rich in dendritic cells, has dose-sparing potential, and allows needle-free delivery. However, few adjuvants are effective, nonreactogenic, and compatible with needle-free delivery devices. In this study, we demonstrate that a combination adjuvant composed of cyclic-di-AMP (cdAMP) and the plant-derived nanoparticle adjuvant Nano-11 significantly enhanced the immune response to ID-injected vaccines in mice and pigs with minimal local reaction at the injection site. The cdAMP/Nano-11 combination adjuvant increased Ag uptake by lymph node-resident and migratory skin dendritic cell subpopulations, including Langerhans cells. ID immunization with cdAMP/Nano-11 expanded the population of germinal center B cells and follicular helper T cells in the draining lymph node and Ag-specific Th1 and Th17 cells in the spleen. It elicited an enhanced immune response with a significant increase of IgG1 and IgG2a responses in mice at a reduced dose compared with i.m. immunization. An increased IgG response was observed following needle-free ID immunization of pigs. Nano-11 and cdAMP demonstrated a strong synergistic interaction, as shown in the activation of mouse, human, and porcine APC, with increased expression of costimulatory molecules and secretion of TNF and IL-1β. The combination adjuvant induced robust activation of both NF-κB and IFN regulatory factor signaling pathways and the NLRP3 inflammasome. We conclude that the combination of Nano-11 and cdAMP is a promising adjuvant for ID delivery of vaccines that supports a balanced immune response.

Anti-Influenza Strategies Based on Nanoparticle Applications

Influenza virus has the potential for being one of the deadliest viruses, as we know from the pandemic's history. The influenza virus, with a constantly mutating genome, is becoming resistant to existing antiviral drugs and vaccines. For that reason, there is an urgent need for developing new therapeutics and therapies. Despite the fact that a new generation of universal vaccines or anti-influenza drugs are being developed, the perfect remedy has still not been found. In this review, various strategies for using nanoparticles (NPs) to defeat influenza virus infections are presented. Several categories of NP applications are highlighted: NPs as immuno-inducing vaccines, NPs used in gene silencing approaches, bare NPs influencing influenza virus life cycle and the use of NPs for drug delivery. This rapidly growing field of anti-influenza methods based on nanotechnology is very promising. Although profound research must be conducted to fully understand and control the potential side effects of the new generation of antivirals, the presented and discussed studies show that nanotechnology methods can effectively induce the immune responses or inhibit influenza virus activity both in vitro and in vivo. Moreover, with its variety of modification possibilities, nanotechnology has great potential for applications and may be helpful not only in anti-influenza but also in the general antiviral approaches.

Pro-Inflammatory Cytokines at Ultra-Low Dose Exert Anti-Inflammatory Effect In Vitro: A Possible Mode of Action Involving Sub-Micron Particles?

Tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) are pro-inflammatory cytokines involved in acute and chronic inflammatory diseases. Indeed, immunotherapy blocking these 2 cytokines has been developed. Micro-immunotherapy (MI) also uses ultra-low doses (ULD) of pro-inflammatory cytokines, impregnated on lactose-sucrose pillules, to counteract their overexpression. The study has been conducted with 2 objectives: examine the anti-inflammatory effect in vitro and the capacity of 2 unitary medicines, TNF-α (27 CH) and IL-1β (27 CH), to reduce the secretion of TNF-α in human primary monocytes and THP-1 cells differentiated with phorbol-12-myristate-13-acetate, after lipopolysaccharide (LPS) exposure; then, investigate the presence of particles possibly containing starting materials using tunable resistive pulse sensing technique. The results show that the unitary medicines, tested at 3 pillules concentrations (5.5, 11 and 22 mM), have reduced the secretion of TNF-α in both models by about 10−20% vs. vehicle control, depending on concentration. In this exploratory study, particles (150−1000 nm) have been detected in MI ULD-impregnated pillules and a hypothesis for MI medicines mode of action has been proposed. Conscious that more evaluations are necessary, authors are cautious in the conclusions because the findings described in the study are still limited, and future investigations may lead to different hypothesis.

Inflammasomes: a preclinical assessment of targeting in atherosclerosis

INTRODUCTION

Inflammasomes are central to atherosclerotic vascular dysfunction with regulatory effects on inflammation, immune modulation, and lipid metabolism. The NLRP3 inflammasome is a critical catalyst for atherogenesis thus highlighting its importance in understanding the pathophysiology of atherosclerosis and for the identification of novel therapeutic targets and biomarkers for the treatment of cardiovascular disease.

AREAS COVERED

This review includes an overview of macrophage lipid metabolism and the role of NLRP3 inflammasome activity in cardiovascular inflammation and atherosclerosis. We highlight key activators, signal transducers and major regulatory components that are being considered as putative therapeutic targets for inhibition of NLRP3-mediated cardiovascular inflammation and atherosclerosis.

EXPERT OPINION

NLRP3 inflammasome activity lies at the nexus between inflammation and cholesterol metabolism; it offers unique opportunities for understanding atherosclerotic pathophysiology and identifying novel modes of treatment. As such, a host of NLRP3 signaling cascade components have been identified as putative targets for drug development. We catalog these current discoveries in therapeutic targeting of the NLRP3 inflammasome and, utilizing the CANTOS trial as the translational (bench-to-bedside) archetype, we examine the complexities, challenges, and ultimate goals facing the field of atherosclerosis research.

Assessment of CafA Targeted BAR-Encapsulated Nanoparticles against Oral Biofilms

Porphyromonas gingivalis adherence to Streptococcus gordonii is a crucial initial event that facilitates the colonization of P. gingivalis, a key pathogen in periodontal disease. As such, blocking these early interactions may present a potential avenue to limit P. gingivalis colonization. Nanoparticles encapsulating a synthetic peptide BAR (BAR-encapsulated NPs) inhibit P. gingivalis/S. gordonii biofilm formation 1.8-fold more potently relative to free BAR. However, BAR-encapsulated NPs, like many orally delivered formulations, may benefit from a strategy that improves their retention in an open flow environment. Here, we sought to enhance the efficacy of BAR-encapsulated NPs by modifying their surfaces with coaggregation factor A (CafA), a fimbrial protein expressed by the early colonizer, Actinomyces oris. We demonstrate that the targeting moiety, CafA, enhances NP binding and exhibits specificity of adherence to S. gordonii, relative to other oral bacterial species. Furthermore, CafA-modified NPs release inhibitory concentrations of BAR for 12 h, a time frame relevant to oral dosage form delivery. Lastly, CafA-modified NPs potently inhibit P. gingivalis/S. gordonii biofilm formation for up to 12 h and are non-toxic at therapeutically-relevant concentrations. These results suggest that CafA-modified NPs represent a novel and efficacious delivery vehicle for localized, targeted delivery of BAR to P. gingivalis preferred niches.

Nanotechnology for COVID-19: Therapeutics and Vaccine Research

The current global health threat by the novel coronavirus disease 2019 (COVID-19) requires an urgent deployment of advanced therapeutic options available. The role of nanotechnology is highly relevant to counter this "virus" nano enemy. Nano intervention is discussed in terms of designing effective nanocarriers to counter the conventional limitations of antiviral and biological therapeutics. This strategy directs the safe and effective delivery of available therapeutic options using engineered nanocarriers, blocking the initial interactions of viral spike glycoprotein with host cell surface receptors, and disruption of virion construction. Controlling and eliminating the spread and reoccurrence of this pandemic demands a safe and effective vaccine strategy. Nanocarriers have potential to design risk-free and effective immunization strategies for severe acute respiratory syndrome coronavirus 2 vaccine candidates such as protein constructs and nucleic acids. We discuss recent as well as ongoing nanotechnology-based therapeutic and prophylactic strategies to fight against this pandemic, outlining the key areas for nanoscientists to step in.

Nanotechnology as a Platform for the Development of Injectable Parenteral Formulations: A Comprehensive Review of the Know-Hows and State of the Art

Within recent decades, the development of nanotechnology has made a significant contribution to the progress of various fields of study, including the domains of medical and pharmaceutical sciences. A substantially transformed arena within the context of the latter is the development and production of various injectable parenteral formulations. Indeed, recent decades have witnessed a rapid growth of the marketed and pipeline nanotechnology-based injectable products, which is a testimony to the remarkability of the aforementioned contribution. Adjunct to the ability of nanomaterials to deliver the incorporated payloads to many different targets of interest, nanotechnology has substantially assisted to the development of many further facets of the art. Such contributions include the enhancement of the drug solubility, development of long-acting locally and systemically injectable formulations, tuning the onset of the drug’s release through the endowment of sensitivity to various internal or external stimuli, as well as adjuvancy and immune activation, which is a desirable component for injectable vaccines and immunotherapeutic formulations. The current work seeks to provide a comprehensive review of all the abovementioned contributions, along with the most recent advances made within each domain. Furthermore, recent developments within the domains of passive and active targeting will be briefly debated.

Hepatitis B virus-induced modulation of liver macrophage function promotes hepatocyte infection

BACKGROUND & AIMS

Liver macrophages can be involved in both pathogen clearance and/or pathogenesis. To get further insight on their role during chronic hepatitis B virus (HBV) infections, our aim was to phenotypically and functionally characterize in vivo and ex vivo the interplay between HBV, primary human liver macrophages (PLMs) and primary blood monocytes differentiated into pro-inflammatory or anti-inflammatory macrophages (M1-MDMs or M2-MDMs, respectively).

METHODS

PLMs or primary blood monocytes, either ex vivo differentiated into M1-MDMs or M2-MDMs, were exposed to HBV and their activation followed by ELISA or quantitative reverse transcription PCR (RT-qPCR). Liver biopsies from HBV-infected patients were analysed by RT-qPCR or immunohistochemistry. Viral parameters in HBV-infected primary human hepatocytes and differentiated HepaRG cells were followed by ELISA, qPCR and RT-qPCR analyses.

RESULTS

HBc protein was present within the macrophages of liver biopsies taken from HBV-infected patients. Macrophages from HBV-infected patients also expressed higher levels of anti-inflammatory macrophage markers than those from non-infected patients. Ex vivo exposure of naive PLMs to HBV led to reduced secretion of pro-inflammatory cytokines. Upon exposure to HBV or HBV-producing cells during differentiation and activation, M1-MDMs secreted less IL-6 and IL-1β, whereas M2-MDMs secreted more IL-10 when exposed to HBV during activation. Finally, cytokines produced by M1-MDMs, but not those produced by HBV-exposed M1-MDMs, decreased HBV infection of hepatocytes.

CONCLUSIONS

Altogether, our data strongly suggest that HBV modulates liver macrophage functions to favour the establishment of infection.

LAY SUMMARY

Hepatitis B virus modulates liver macrophage function in order to favour the establishment and likely maintenance of infection. It impairs the production of the antiviral cytokine IL-1β, while promoting that of IL-10 in the microenvironment. This phenotype can be recapitulated in naive liver macrophages or monocyte-derived-macrophages ex vivo by short exposure to the virus or cells replicating the virus, thus suggesting an "easy to implement" mechanism of inhibition.

Designing inorganic nanomaterials for vaccines and immunotherapies

Vaccines and immunotherapies have changed the face of health care. Biomaterials offer the ability to improve upon these medical technologies through increased control of the types and concentrations of immune signals delivered. Further, these carriers enable targeting, stability, and delivery of poorly soluble cargos. Inorganic nanomaterials possess unique optical, electric, and magnetic properties, as well as defined chemistry, high surface-to-volume- ratio, and high avidity display that make this class of materials particularly advantageous for vaccine design, cancer immunotherapy, and autoimmune treatments. In this review we focus on this understudied area by highlighting recent work with inorganic materials - including gold nanoparticles, carbon nanotubes, and quantum dots. We discuss the intrinsic features of these materials that impact the interactions with immune cells and tissue, as well as recent reports using inorganic materials across a range of emerging immunological applications.

NLRP3 inflammasome in ischemic stroke: As possible therapeutic target

Inflammation is a devastating pathophysiological process during stroke, a devastating disease that is the second most common cause of death worldwide. Activation of the NOD-like receptor protein (NLRP3)-infammasome has been proposed to mediate inflammatory responses during ischemic stroke. Briefly, NLRP3 inflammasome activates caspase-1, which cleaves both pro-IL-1 and pro-IL-18 into their active pro-inflammatory cytokines that are released into the extracellular environment. Several NLRP3 inflammasome inhibitors have been promoted, including small molecules, type I interferon, micro RNAs, nitric oxide, and nuclear factor erythroid-2 related factor 2 (Nrf2), some of which are potentially efficacious clinically. This review will describe the structure and cellular signaling pathways of the NLRP3 inflammasome during ischemic stroke, and current evidence for NLRP3 inflammasome inhibitors.

Interleukin-10 inhibits interleukin-1β production and inflammasome activation of microglia in epileptic seizures

BACKGROUND

Microglia are important for secreting chemical mediators of inflammatory responses in the central nervous system. Interleukin (IL)-10 and IL-1β secreted by glial cells support neuronal functions, but the related mechanisms remain vague. Our goal was to demonstrate the efficacy of IL-10 in suppressing IL-1β and in inflammasome activation in mice with epileptic seizure based on an epileptic-seizure mouse model.

METHODS

In this study, mice in which epileptic seizures were induced by administering picrotoxin (PTX) were used as a case group, and mice injected with saline were employed as the control group. The expression of nucleic acids, cytokines, or signaling pathways was detected by reverse transcription-polymerase chain reaction (RT-PCR), enzyme-linked immunosorbent assay (ELISA), flow cytometry, and Western blotting.

RESULTS

Our results demonstrated that IL-10 inhibits IL-1β production through two distinct mechanisms: (1) Treatment with lipopolysaccharides (LPS) results in IL-10 overexpression in microglia and reduced NLRP3 inflammasome activity, thus inhibiting caspase-1-related IL-1β maturation; (2) next, autocrine IL-10 was found to subsequently promote signal transducer and activator of transcription-3 (STAT-3), reducing amounts of pro-IL-1β.

CONCLUSIONS

Our results indicate that IL-10 is potentially effective in the treatment of inflammation encephalopathy, and suggest the potential usefulness of IL-10 for treating autoimmune or inflammatory ailments.

Amorphous silicon dioxide nanoparticles modulate immune responses in a model of allergic contact dermatitis

Amorphous silicon dioxide nanoparticles (SiNPs) are ubiquitous, and they are currently found in cosmetics, drugs, and foods. Biomedical research is also focused on using these nanoparticles as drug delivery and bio-sensing platforms. Due to the high potential for skin exposure to SiNPs, research into the effect of topical exposure on both healthy and inflammatory skin models is warranted. While we observe only minimal effects of SiNPs on healthy mouse skin, there is an immunomodulatory effect of these NPs in a model of allergic contact dermatitis. The effect appears to be mediated partly by keratinocytes and results in decreases in epidermal hyperplasia, inflammatory cytokine release, immune cell infiltration, and a subsequent reduction in skin swelling. Additional research is required to further our mechanistic understanding and to validate the extent of this immunomodulatory effect in human subjects in order to assess the potential prophylactic use of SiNPs for treating allergic skin conditions.

Challenges of using lipopolysaccharides for cancer immunotherapy and potential delivery-based solutions thereto

Despite being one of the earliest Toll-like receptor (TLR)-based cancer immunotherapeutics discovered and investigated, the full extent of lipopolysaccharide (LPS) potentials within this arena remains hitherto unexploited. In this review, we will debate the challenges that have complicated the improvement of LPS-based immunotherapeutic approaches in cancer therapy. Based on their nature, those will be discussed with a focus on side effect-related, tolerance-related and in vivo model-related challenges. We will then explore how drug delivery strategies can be integrated within this domain to address such challenges in order to improve the therapeutic outcome, and will present a summary of the studies that have been dedicated thereto. This paper may inspire further developments based on reconciling the advantages of drug delivery and LPS-based cancer immunotherapy.

Nanomaterial Exposure Induced Neutrophil Extracellular Traps: A New Target in Inflammation and Innate Immunity

Nanotechnology has become a novel subject with impact in many research and technology areas. Nanoparticles (NPs), as a key component in nanotechnology, are widely used in many areas such as optical, magnetic, electrical, and mechanical engineering. The biomedical and pharmaceutical industries have embraced NPs as a viable drug delivery modality. As such, the potential for NP-induced cytotoxicity has emerged as a major concern for NP drug delivery systems. Thus, it is important to understand how NPs affect the innate immune system. As the most abundant myeloid cell type in innate immune responses, neutrophils are critical for concerns about potentially toxic side effects of NPs. When activated by innate immune stimuli, neutrophils may initiate NETosis to release neutrophil extracellular traps (NETs). Herein, we have reviewed the relationship between NPs and the induction of NETosis and release of NETs.

Biocompatible Polymer Nanoparticles for Drug Delivery Applications in Cancer and Neurodegenerative Disorder Therapies

Polymer nanoparticles (NPs) represent one of the most innovative non-invasive approaches for drug delivery applications. NPs main objective is to convey the therapeutic molecule be they drugs, proteins, or nucleic acids directly into the target organ or tissue. Many polymers are used for the synthesis of NPs and among the currently most employed materials several biocompatible synthetic polymers, namely polylactic acid (PLA), poly lactic-co-glycolic acid (PLGA), and polyethylene glycol (PEG), can be cited. These molecules are made of simple monomers which are naturally present in the body and therefore easily excreted without being toxic. The present review addresses the different approaches that are most commonly adopted to synthetize biocompatible NPs to date, as well as the experimental strategies designed to load them with therapeutic agents. In fact, drugs may be internalized in the NPs or physically dispersed therein. In this paper the various types of biodegradable polymer NPs will be discussed with emphasis on their applications in drug delivery. Close attention will be devoted to the treatment of cancer, where both active and passive targeting is used to enhance efficacy and reduce systemic toxicity, and to diseases affecting the central nervous system, inasmuch as NPs can be modified to target specific cells or cross membrane barriers.

Amphiphilic nanoparticle delivery enhances the anticancer efficacy of a TLR7 ligand via local immune activation

Although immunotherapy shows great promise for the long-term control of cancer, many tumors still fail to respond to treatment. To improve the outcome, the delivery of immunostimulants to the lymph nodes draining the tumor, where the antitumor immune response is initiated, is key. Efforts to use nanoparticles as carriers for cancer immunotherapy have generally required targeting agents and chemical modification of the drug, and have unfortunately resulted in low delivery and therapeutic efficiency. Here, we report on the efficacy of gold nanoparticles with approximately 5 nm hydrodynamic diameter coated with a mixture of 1-octanethiol and 11-mercaptoundecanesulfonic acid for the delivery of an immunostimulatory TLR7 ligand to tumor-draining lymph nodes. The drug was loaded without modification through nonspecific adsorption into the ligand shell of the nanoparticles, taking advantage of their amphiphilic nature. After loading, nanoparticles retained their stability in solution without significant premature release of the drug, and the drug cargo was immunologically active. Upon subcutaneous injection into tumor-bearing mice, the drug-loaded particles were rapidly transported to the tumor-draining lymph nodes. There, they induced a local immune activation and fostered a cytotoxic T-cell response that was specific for the tumor. Importantly, the particle-delivered TLR7 ligand blocked the growth of large established tumors and significantly prolonged survival compared to the free form of the drug. Thus, we demonstrate for the first time that nanoparticle delivery of a TLR7 immunostimulant to the tumor-draining lymph nodes enhances antitumor immunity and improves the outcome of cancer immunotherapy.

A nanoparticle-based approach to improve the outcome of cancer active immunotherapy with lipopolysaccharides

This study sought to develop a simple nanoparticle-based approach to enhance the efficiency and tolerability of lipopolysaccharide (LPS), a potent ligand of Toll-like Receptor 4 (TLR4), for immunotherapy in cancer. Despite holding promise within this context, the strong pro-inflammatory properties of LPS also account for its low tolerability given localized and systemic side effects, which restrict the administrable dosage. Herein, we investigated the effect of LPS decoration as a surface-active molecule on a polymeric matrix upon its efficiency and tolerability. The LPS-decorated nanoparticles (LPS-NP) were about 150 nm in size, with slightly negative zeta potential (about -15 mV) and acceptable LPS incorporation (about 70%). In vitro, the particles accounted for a higher induction of apoptosis in tumor cells cultured with murine splenocytes compared to LPS solution. When used for the treatment of a murine syngeneic colorectal tumor model, higher intratumoral deposition of the particle-bound LPS was observed. Furthermore, unlike LPS solution, which accounted for localized necrosis at high concentrations, treatment of tumor-bearing animals with equivalent doses of LPS-NP was well tolerated. We propose that the observed localized necrosis can be Shwartzman phenomenon, which, due to modulated 24-h post-injection systemic TNF-α and LPS concentrations, have been avoided in case of LPS-NP. This has in turn enhanced the therapeutic efficiency and enabled complete tumor regression at concentrations at which LPS solution was intolerable. The findings indicate that nanoparticles can serve as beyond carriers for the delivery of superficially decorated LPS molecules, but impact their overall efficiency and tolerability in cancer therapy.

A systematic electron microscopic study on the uptake of barium sulphate nano-, submicro-, microparticles by bone marrow-derived phagocytosing cells

Nanoparticles can act as transporters for synthetic molecules and biomolecules into cells, also in immunology. Antigen-presenting cells like dendritic cells are important targets for immunotherapy in nanomedicine. Therefore, we have used primary murine bone marrow-derived phagocytosing cells (bmPCs), i.e. dendritic cells and macrophages, to study their interaction with spherical barium sulphate particles of different size (40 nm, 420 nm, and 1 µm) and to follow their uptake pathway. Barium sulphate is chemically and biologically inert (no dissolution, no catalytic effects), i.e. we can separate the particle uptake effect from potential biological reactions. The colloidal stabilization of the nanoparticles was achieved by a layer of carboxymethylcellulose (CMC) which is biologically inert and gives the particles a negative zeta potential (i.e. charge). The particles were made fluorescent by conjugating 6-aminofluoresceine to CMC. Their uptake was visualized by flow cytometry, confocal laser scanning microscopy (CLSM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and correlative light and electron microscopy (CLEM). Barium sulphate particles of all sizes were readily taken up by dendritic cells and even more by macrophages, with the uptake increasing with time and particle concentration. They were mainly localized inside phagosomes, heterophagosomes, and in the case of nanoparticles also in the nearby cytosol. No particles were found in the nucleus. In nanomedicine, inorganic nanoparticles from the nanometer to the micrometer size are therefore well suited as transporters of biomolecules, including antigens, into dendritic cells and macrophages. The presented model system may also serve to describe the aseptic loosening of endoprostheses caused by abrasive wear of inert particles and the subsequent cell reaction, a question which relates to the field of nanotoxicology. STATEMENT OF SIGNIFICANCE: The interaction of particles and cells is at the heart of nanomedicine and nanotoxicology, including abrasive wear from endoprostheses. It also comprises the immunological reaction to different kinds of nanomaterials, triggered by an immune response, e.g. by antigen-presenting cells. However, it is often difficult to separate the particle effect from a chemical or biochemical reaction to particles or their cargo. We show how chemically inert barium sulphate particles with three different sizes (nano, sub-micro, and micro) interact with relevant immune cells (primary dendritic cells and macrophages). Particles of all three sizes are readily taken up into both cell types by phagocytosis, but the uptake by macrophages is significantly more prominent than that by dendritic cells. The cells take up particles until they are virtually stuffed, but without direct adverse effect. The uptake increases with time and particle concentration. Thus, we have an ideal model system to follow particles into and inside cells without the side effect of a chemical particle effect, e.g. by degradation or ion release.

Liver macrophages: Friend or foe during hepatitis B infection?

The Hepatitis B virus chronically infects the liver of 250 million people worldwide. Over the past decades, major advances have been made in the understanding of Hepatitis B virus life cycle in hepatocytes. Beside these parenchymal cells, the liver also contains resident and infiltrating myeloid cells involved in immune responses to pathogens and much less is known about their interplay with Hepatitis B virus. In this review, we summarized and discussed the current knowledge of the role of liver macrophages (including Kupffer cells and liver monocyte-derived macrophages), in HBV infection. While it is still unclear if liver macrophages play a role in the establishment and persistence of HBV infection, several studies disclosed data suggesting that HBV would favour liver macrophage anti-inflammatory phenotypes and thereby increase liver tolerance. In addition, alternatively activated liver macrophages might also play in the long term a key role in hepatitis B-associated pathogenesis, especially through the activation of hepatic stellate cells. Therapies aiming at a transient activation of pro-inflammatory liver macrophages should therefore be considered for the treatment of chronic HBV infection.

Co-delivery of a CD4 T cell helper epitope via covalent liposome attachment with a surface-arrayed B cell target antigen fosters higher affinity antibody responses

Liposomal vaccines incorporating adjuvant and CD4 T cell helper peptides enhance antibody responses against weakly immunogenic B cell epitopes such as found in the membrane proximal external region (MPER) of the HIV-1 gp41 subunit. While the inclusion of exogenous helper peptides in vaccine formulations facilitates stronger and more durable antibody responses, the helper peptide incorporation strategy per se may influence the overall magnitude and quality of B cell target antigen immunogenicity. Both variability in individual peptide encapsulation as well as the potential for liposome surface-associated helper peptides to misdirect the humoral response are potential parameters impacting outcome. In this study, we used MPER/liposome vaccines as a model system to examine how the mode of the potent LACK T helper peptide formulation modulates antibody responses against the MPER antigen. We directly compared liposome surface-arrayed palmitoyl LACK (pLACK) versus soluble LACK (sLACK) encapsulated in the liposomes and free in solution. Independent of LACK formulation methods, dendritic cell activation and LACK presentation were equivalent in vivo. The frequency of MPER-specific GC B cells promoted by sLACK was higher than that stimulated by pLACK formulation, a finding associated with a significantly greater frequency of LACK-specific GC B cells induced by pLACK. While there were no significant differences in the quantity of MPER-specific serological responses, the MPER-specific antibody titer trended higher with sLACK formulated vaccines at the lower dose of LACK. However, pLACK generated relatively greater MPER-specific antibody affinities than those induced by sLACK-formulated vaccines. Overall, the results suggest that liposomal surface-associated LACK enhances immunogenicity of LACK through better engagement of LACK-specific B cells. Of note, this is not detrimental to the induction of MPER-specific immune responses; rather, the elicitation of higher affinity anti-MPER antibodies benefits from augmented help delivered via covalent linkage of the pLACK CD4 T cell epitope in conjunction with MPER/liposome presentation.

Disease-Triggered Drug Release Effectively Prevents Acute Inflammatory Flare-Ups, Achieving Reduced Dosing

For conditions with inflammatory flare-ups, fast drug-release from a depot is crucial to reduce cell infiltration and prevent long-term tissue destruction. While this concept has been explored for chronic diseases, preventing acute inflammatory flares has not been explored. To address this issue, a preventative inflammation-sensitive system is developed and applied to acute gout, a condition where millions of inflammatory cells are recruited rapidly, causing excruciating and debilitating pain. Rapid drug release is first demonstrated from a pH-responsive acetalated dextran particle loaded with dexamethasone (AcDex-DXM), reducing proinflammatory cytokines in vitro as efficiently as free drug. Then, using the air pouch model of gout, mice are pretreated 24 h before inducing inflammation. AcDex-DXM reduces overall cell infiltration with decreased neutrophils, increases monocytes, and diminishes cytokines and chemokines. In a more extended prophylaxis model, murine joints are pretreated eight days before initiating inflammation. After quantifying cell infiltration, only AcDex-DXM reduces the overall joint inflammation, where neither free drug nor a conventional drug-depot achieves adequate anti-inflammatory effects. Here, the superior efficacy of disease-triggered drug-delivery to prevent acute inflammation is demonstrated over free drug and slow-release depots. This approach and results promise exciting treatment opportunities for multiple inflammatory conditions suffering from acute flares.