Antigen- and Epitope-Delivering Nanoparticles Targeting Liver Induce Comparable Immunotolerance in Allergic Airway Disease and Anaphylaxis as Nanoparticle-Delivering Pharmaceuticals

Targeting Polymeric Nanoparticles to Specific Cell Populations in the Liver

Nanoparticles (NPs) are beneficial for delivery of drugs in a variety of settings, serving to protect their cargo and allow for sustained release. Polymeric NPs offer several advantages as therapeutics carriers due to their tunable characteristics like size and shape, ease of manufacturing, and biocompatibility. Despite this, there are no polymeric NPs that are approved for treatment of liver diseases. This is surprising since─when administered intravenously─the majority of NPs accumulate in cells in the liver. NP characteristics like size and surface charge can be altered to affect distribution to the liver, and even cellular distribution, but the conjugation of targeting ligands onto the NP surface for specific receptors on the cells is an important approach for enhancing cell specific delivery. Enhancing cell-specific targeting of conjugated NPs in the liver has two major hurdles: 1) avoiding accumulation of NPs in the liver resident macrophages known as Kupffer cells, which are optimized to phagocytose particulates, and 2) overcoming the transport barriers associated with architectural changes of the diseased liver. To identify the structures and mechanisms most important in NP design, NP administration during ex vivo perfusion (EVP)─achieved by anatomically isolating an organ by perfusing it outside the body─may be the most important and efficient approach. However, EVP is currently underutilized in the NP field, with limited research published on NPs delivered during liver EVP, and therefore representing an opportunity for future investigations.

Tolerogenic nanovaccines for the treatment of type I allergic diseases

The high prevalence of type I allergic diseases such as allergic rhinitis, allergic asthma, food allergies, allergic conjunctivitis, and atopic dermatitis has emerged as a significant public health concern globally. Failure of immune tolerance to ordinarily harmless substances or stimulation, and subsequent induction of T helper 2 cells by antigen-presenting cells evokes the allergic immune response, which results in persistent inflammation, tissue damage, and organ function impairment. Current therapeutic approaches for allergic diseases include avoiding allergen exposure, corticosteroids, biologics, etc. However, these strategies only relieve allergic symptoms but hardly prevent the deteriorative progression and may have adverse effects on patients. With the rapid development of nanotechnology and immunology, emerging tolerogenic nanovaccines represent novel approaches with the potential to cure type I allergic diseases rather than merely alleviate symptoms. In this review, we expound the burgeoning field of tolerogenic nanovaccines against type I allergic diseases, highlight various types of antigens employed in constructing allergen extracts, protein/peptide and nucleic acid-based tolerogenic nanovaccines, and discuss their application in allergic rhinitis, allergic asthma, food allergies, allergic conjunctivitis, and atopic dermatitis.

Unlocking Transplant Tolerance with Biomaterials

For patients suffering from organ failure due to injury or autoimmune disease, allogeneic organ transplantation with chronic immunosuppression is considered the god standard in terms of clinical treatment. However, the true "holy grail" of transplant immunology is operational tolerance, in which the recipient exhibits a sustained lack of alloreactivity toward unencountered antigen presented by the donor graft. This outcome is resultant from critical changes to the phenotype and genotype of the immune repertoire predicated by the activation of specific signaling pathways responsive to soluble and mechanosensitive cues. Biomaterials have emerged as a medium for interfacing with and reprogramming these endogenous pathways toward tolerance in precise, minimally invasive, and spatiotemporally defined manners. By viewing seminal and contemporary breakthroughs in transplant tolerance induction through the lens of biomaterials-mediated immunomodulation strategies-which include intrinsic material immunogenicity, the depot effect, graft coatings, induction and delivery of tolerogenic immune cells, biomimicry of tolerogenic immune cells, and in situ reprogramming-this review emphasizes the stunning diversity of approaches in the field and spotlights exciting future directions for research to come.

A comprehensive overview of tolerogenic vaccine adjuvants and their modes of action

Tolerogenic vaccines represent a therapeutic approach to induce antigen-specific immune tolerance to disease-relevant antigens. As general immunosuppression comes with significant side effects, including heightened risk of infections and reduced anti-tumor immunity, antigen-specific tolerance by vaccination would be game changing in the treatment of immunological conditions such as autoimmunity, anti-drug antibody responses, transplantation rejection, and hypersensitivity. Tolerogenic vaccines induce antigen-specific tolerance by promoting tolerogenic antigen presenting cells, regulatory T cells, and regulatory B cells, or by suppressing or depleting antigen-specific pathogenic T and B cells. The design of tolerogenic vaccines vary greatly, but they all deliver a disease-relevant antigen with or without a tolerogenic adjuvant. Tolerogenic adjuvants are molecules which mediate anti-inflammatory or immunoregulatory effects and enhance vaccine efficacy by modulating the immune environment to favor a tolerogenic immune response to the vaccine antigen. Tolerogenic adjuvants act through several mechanisms, including immunosuppression, modulation of cytokine signaling, vitamin signaling, and modulation of immunological synapse signaling. This review seeks to provide a comprehensive examination of tolerogenic adjuvants currently utilized in tolerogenic vaccines, describing their mechanism of action and examples of their use in human clinical trials and animal models of disease.

Immunomodulatory potential of rapamycin-loaded mesoporous silica nanoparticles: pore size-dependent drug loading, release, and in vitro cellular responses

Rapamycin is a potent immunosuppressive drug that has been recently proposed for a wide range of applications beyond its current clinical use. For some of these proposed applications, encapsulation in nanoparticles is key to ensure therapeutic efficacy and safety. In this work, we evaluate the effect of pore size on mesoporous silica nanoparticles (MSN) as rapamycin nanocarriers. The successful preparation of MSN with 4 different pore sizes was confirmed by dynamic light scattering, zeta potential, transmission electron microscopy and N2 adsorption. In these materials, rapamycin loading was pore size-dependent, with smaller pore MSN exhibiting greater loading capacity. Release studies showed sustained drug release from all MSN types, with larger pore MSN presenting faster release kinetics. In vitro experiments using the murine dendritic cell (DC) line model DC2.4 showed that pore size influenced the biological performance of MSN. MSN with smaller pore sizes presented larger nanoparticle uptake by DC2.4 cells, but were also associated with slightly larger cytotoxicity. Further evaluation of DC2.4 cells incubated with rapamycin-loaded MSN also demonstrated a significant effect of MSN pore size on their immunological response. Notably, the combination of rapamycin-loaded MSN with an inflammatory stimulus (lipopolysaccharide, LPS) led to changes in the expression of DC activation markers (CD40 and CD83) and in the production of the proinflammatory cytokine TNF-α compared to LPS-treated DC without nanoparticles. Smaller-pored MSN induced more substantial reductions in CD40 expression while eliciting increased CD83 expression, indicating potential immunomodulatory effects. These findings highlight the critical role of MSN pore size in modulating rapamycin loading, release kinetics, cellular uptake, and subsequent immunomodulatory responses.

Innate immunity-modulating nanobiomaterials for controlling inflammation resolution

The acute inflammatory response is an inherent protective mechanism, its unsuccessful resolution can contribute to disease pathogenesis and potentially lead to death. Innate immune cells are the first line of host defenders and play a substantial role in inflammation initiation, amplification, resolution, or subsequent disease progression. As the resolution of inflammation is an active and highly regulated process, modulating innate immune cells, including neutrophils, monocytes and macrophages, and endothelial cells, and their interactions offer opportunities to control excessive inflammation. Nanobiomaterials have shown superior therapeutic potential in inflammation-related diseases by manipulating inflammatory responses because nanobiomaterials can target and interact with innate immune cells. Versatile nanobiomaterials can be designed for targeted modulation of specific innate immune responses. Nanopro-resolving medicines have been prepared both with pro-resolving lipid mediators and peptides each demonstrated to active resolution of inflammation in animal disease models. Here, we review innovative nanobiomaterials for modulating innate immunity and alleviating inflammation. We summarise the strategies converging the design of nanobiomaterials and the nano-bio interaction in modulating innate immune profiles and propelling the advancement of nanobiomaterials for inflammatory disease treatments. We also propose the future perspectives and translational challenges of nanobiomaterials that need to be overcome in this swiftly rising field.

Dietary sodium modulates mTORC1-dependent trained immunity in macrophages to accelerate CKD development

Chronic Kidney Disease (CKD) is a significant global health issue linked to dietary habits, especially high salt intake. However, the precise mechanisms driving this progression remain incompletely understood. This study reveals that a high-salt diet intensifies macrophage trained immunity, leading to a marked pro-inflammatory response upon repeated pathogenic exposures, as evidenced by increased renal damage and fibrosis. Under high-salt conditions, there was an induction of CD45+F4/80+ macrophage infiltration into the renal tissue, accompanied by heightened production of inflammatory cytokines. Distinct responses were observed between circulating and resident renal macrophages to a high-salt diet, with a notable upsurge in the migration of pro-inflammatory macrophages, driven by CCL2-CCR2 signaling and aberrant mTORC1 pathway activation. Treatment with rapamycin-liposome effectively reduced this inflammatory cascade by mitigating mTORC1 signaling. Transplantation of monocytes from CKD mice with a high-salt diet significantly exacerbates renal inflammatory damage in the host mice, showing increased migratory tendency and inflammatory activity. The cell co-culture experiment further confirmed that macrophages derived from CKD mice, particularly those under conditions of high salt exposure, significantly induced apoptosis and inflammatory responses in renal tubular cells. Taken together, recurrent exposure to LPS elicits the activation of trained immunity, consequently augmenting inflammatory response of monocytes/macrophages in the involved kidneys. The high-salt diet exacerbates this phenomenon, attributable at least in part to the overactivation of the mTORC1 pathway. This research emphasizes the importance of dietary modulation and targeted immunological interventions in slowing CKD progression, providing new insights into mTORC1-mediated pathophysiological mechanisms and potential management strategies for CKD.

Enhancing RNA-lipid nanoparticle delivery: Organ- and cell-specificity and barcoding strategies

Recent advancements in RNA therapeutics highlight the critical need for precision gene delivery systems that target specific organs and cells. Lipid nanoparticles (LNPs) have emerged as key vectors in delivering mRNA and siRNA, offering protection against enzymatic degradation, enabling targeted delivery and cellular uptake, and facilitating RNA cargo release into the cytosol. This review discusses the development and optimization of organ- and cell-specific LNPs, focusing on their design, mechanisms of action, and therapeutic applications. We explore innovations such as DNA/RNA barcoding, which facilitates high-throughput screening and precise adjustments in formulations. We address major challenges, including improving endosomal escape, minimizing off-target effects, and enhancing delivery efficiencies. Notable clinical trials and recent FDA approvals illustrate the practical applications and future potential of LNP-based RNA therapies. Our findings suggest that while considerable progress has been made, continued research is essential to resolve existing limitations and bridge the gap between preclinical and clinical evaluation of the safety and efficacy of RNA therapeutics. This review highlights the dynamic progress in LNP research. It outlines a roadmap for future advancements in RNA-based precision medicine.

Impact of antigen loading in tolerogenic nanoparticles to mitigate Th2-mediated allergic lung inflammation

Allergic disease is a major global health concern that imposes significant life-altering and economic burdens on affected individuals. However, there is still no cure. Polymer-based nanoparticles (NP) have shown the potential to induce antigen (Ag)-specific immune tolerance in various Th1/17 and Th2-mediated immune disorders including autoimmunity and allergy. Common methods by which Ags are associated with NPs are through surface conjugation or encapsulation. However, these Ag delivery strategies can be associated with several caveats that dampen their effectiveness such as uncontrolled Ag loading, a high Ag burst release, and an increased immune recognition profile. We previously developed Ag-polymer conjugate NPs (acNPs) to overcome those noted limitations, while allowing for controlled delivery of precise quantities of Ag to innate immune cells for Ag-specific CD4 T cell modulation. Here, we utilized ovalbumin (OVA) protein-poly(lactic-co-glycolic acid) (PLGA) conjugate NPs (acNP-OVA) to elucidate the impact of Ag loading on the induction of Th2 tolerance using a prophylactic and therapeutic OVA/ALUM-induced mouse model of allergic lung inflammation (ALI) in comparison to Ag-encapsulated PLGA NPs (NP(Ag)). We demonstrate that acNP-OVA formulations reduced OVA-specific IgE and inhibited Th2 cytokine secretions in an Ag loading-dependent manner when administered prophylactically. Administration of acNP-OVA to pre-sensitized mice did not affect OVA-specific IgE and Th2 cytokines tended to be reduced, however, there was no clear Ag loading dependency. acNP-OVA with medium-to-low Ag loadings were well tolerated, while formulations with high Ag loadings, including NP(Ag) resulted in anaphylaxis. Overall, our results clarify the relationship between Ag loading and Ag-specific IgE and Th2 cytokine responses in a murine model of ALI, which provides insight useful for future design of tolerogenic NP-based immunotherapies.

Platelet Membrane-Coated Curcumin-PLGA Nanoparticles Promote Astrocyte-Neuron Transdifferentiation for Intracerebral Hemorrhage Treatment

Intracerebral hemorrhage (ICH) is a hemorrhagic disease with high mortality and disability rates. Curcumin is a promising drug for ICH treatment due to its multiple biological activities, but its application is limited by its poor watersolubility and instability. Herein, platelet membrane-coated curcumin polylactic-co-glycolic acid (PLGA) nanoparticles (PCNPs) are prepared to achieve significantly improved solubility, stability, and sustained release of curcumin. Fourier transform infrared spectra and X-ray diffraction assays indicate good encapsulation of curcumin within nanoparticles. Moreover, it is revealed for the first time that curcumin-loaded nanoparticles can not only suppress hemin-induced astrocyte proliferation but also induce astrocytes into neuron-like cells in vitro. PCNPs are used to treat rat ICH by tail vein injection, using in situ administration as control. The results show that PCNPs are more effective than curcumin-PLGA nanoparticles in concentrating on hemorrhagic lesions, inhibiting inflammation, suppressing astrogliosis, promoting neurogenesis, and improving motor functions. The treatment efficacy of intravenously administered PCNPs is comparable to that of in situ administration, indicating a good targeting effect of PCNPs on the hemorrhage site. This study provides a potent treatment for hemorrhagic injuries and a promising solution for efficient delivery of water-insoluble drugs using composite materials of macromolecules and cell membranes.

Recent updates in applications of nanomedicine for the treatment of hepatic fibrosis

Over recent decades, nanomedicine has played an important role in the enhancement of therapeutic outcomes compared to those of conventional therapy. At the same time, nanoparticle drug delivery systems offer a significant reduction in side effects of treatments by lowering the off-target biodistribution of the active pharmaceutical ingredients. Cancer nanomedicine represents the most extensively studied nanotechnology application in the field of pharmaceutics and pharmacology since the first nanodrug for cancer treatment, liposomal doxorubicin (Doxil®), has been approved by the FDA. The advancement of cancer nanomedicine and its enormous technological success also included various other target diseases, including hepatic fibrosis. This confirms the versatility of nanomedicine for improving therapeutic activity. In this review, we summarize recent updates of nanomedicine platforms for improving therapeutic efficacy regarding liver fibrosis. We first emphasize the challenges of conventional drugs for penetrating the biological barriers of the liver. After that, we highlight design principles of nanocarriers for achieving improved drug delivery of antifibrosis drugs through passive and active targeting strategies.

Targeted delivery strategies: The interactions and applications of nanoparticles in liver diseases

In recent years, nanoparticles have been broadly utilized in various drugs delivery formulations. Nanodelivery systems have shown promise in solving problems associated with the distribution of hydrophobic drugs and have promoted the accumulation of nanomedicines in the circulation or in organs. However, the injection dose of nanoparticles (NPs) is much greater than that needed by diseased tissues or organs. In other words, most of the NPs are localized off-target and do not reach the desired tissue or organs. With the rapid development of biodegradable and biosafety nanomaterials, the nanovectors represent assurance of safety. However, the off-target effects also induce concerns about the application of NPs, especially in the delivery of gene editing tools. Therefore, a complete understanding of the biological responses to NPs in the body will clearly guide the design of targeted delivery of NPs. The different properties of various nanodelivery systems may induce diverse interactions between carriers and organs. In this review, we describe the relationship between the liver, the most influenced organ of systemic administration of NPs, and targeted delivery nanoplatforms. Various transport vehicles have adopted multiple delivery strategies for the targeted delivery to the cells in the homeostasis liver and in diseased liver. Additionally, nanodelivery systems provide a novel strategy for treating incurable diseases. The appearance of a targeted delivery has profoundly improved the application of NPs to liver diseases.

Calreticulin P-domain-derived "Eat-me" peptides for enhancing liposomal uptake in dendritic cells

Discovering new ligands for enhanced drug uptake and delivery has been the core interest of the drug delivery field. This study capitalizes on the natural "eat-me" signal of calreticulin (CRT), proposing a novel strategy for functionalizing liposomes to improve cellular uptake. CRT is presented on the surfaces of apoptotic cells, and it plays a crucial role in immunogenic cell death (ICD). This is because it is essential for antigen uptake via low-density lipoprotein (LDL) receptor-mediated phagocytosis. Inspired by this mechanism, we interrogated CRT's "eat-me" feature using CRT-derived peptides to functionalize liposomes. We studied liposomal formulation stability, properties, cellular uptake, toxicity, and intracellular trafficking in dendritic cells. We identified key peptide fragments of CRT, specifically from the hydrophilic P-domain, that are compatible with liposomal formulations. Contrary to the more hydrophobic N-domain peptides, the P-domain peptides induced significantly higher liposomal uptake in DC2.4 dendritic cells than cationic DOTAP and anionic DPPG liposomes without inducing toxicity. The P-domain-derived peptides led to enhanced liposomal uptake into DC2.4 dendritic cells compared to the standard DPPC liposomes. The uptake can be partially blocked by the receptor-associated protein (RAP). Upon internalization, P-domain-peptide-decorated liposomes showed higher co-localization with lysosomes compared to the standard DPPC liposomes. Our findings illuminate CRT's operational role and identify P-domain peptides as promising agents for developing biomimetic drug delivery systems that can potentially replicate CRT's "eat-me" function.

Tolerogenic Nano-/Microparticle Vaccines for Immunotherapy

Autoimmune diseases, allergies, transplant rejections, generation of antidrug antibodies, and chronic inflammatory diseases have impacted a large group of people across the globe. Conventional treatments and therapies often use systemic or broad immunosuppression with serious efficacy and safety issues. Tolerogenic vaccines represent a concept that has been extended from their traditional immune-modulating function to induction of antigen-specific tolerance through the generation of regulatory T cells. Without impairing immune homeostasis, tolerogenic vaccines dampen inflammation and induce tolerogenic regulation. However, achieving the desired potency of tolerogenic vaccines as preventive and therapeutic modalities calls for precise manipulation of the immune microenvironment and control over the tolerogenic responses against the autoantigens, allergens, and/or alloantigens. Engineered nano-/microparticles possess desirable design features that can bolster targeted immune regulation and enhance the induction of antigen-specific tolerance. Thus, particle-based tolerogenic vaccines hold great promise in clinical translation for future treatment of aforementioned immune disorders. In this review, we highlight the main strategies to employ particles as exciting tolerogenic vaccines, with a focus on the particles' role in facilitating the induction of antigen-specific tolerance. We describe the particle design features that facilitate their usage and discuss the challenges and opportunities for designing next-generation particle-based tolerogenic vaccines with robust efficacy to promote antigen-specific tolerance for immunotherapy.

Transdermally delivered tolerogenic nanoparticles induced effective immune tolerance for asthma treatment

Induction of antigen-specific immune tolerance for the treatment of allergic or autoimmune diseases is an attractive strategy. Herein, we investigated the protective effect of a transdermal microneedle patch against allergic asthma by stimulating allergen-specific immune tolerance. We fabricated biodegradable tolerogenic nanoparticles (tNPs) that are loaded with a model allergen ovalbumin (OVA) and an immunomodulator rapamycin, and filled the tNPs into microneedle tips by centrifugation to form sustained-release microneedles. After intradermal immunization, the microneedles successfully delivered the cargos into the skin and sustainedly released them for over 96 h. Importantly, the microneedles induced allergen-specific regulatory T cells (Treg), decreased the levels of pro-inflammatory cytokines and antibodies while increased anti-inflammation cytokines, finally leading to restored immune homeostasis. The lung tissue analysis illustrated that the sustained-release microneedles significantly reduced the infiltration of eosinophils, decreased the accumulation of mucus and collagen, and significantly relived asthma symptoms. Our results suggested that the sustained-release microneedle-based transdermal delivery system can induce antigen-specific immune tolerance with improved compliance and efficacy, providing a new therapeutic strategy for the treatment of allergic and autoimmune diseases.

Harnessing Nanovaccines for Effective Immunization─A Special Concern on COVID-19: Facts, Fidelity, and Future Prospective

Nanotechnology has emerged as a transformative pathway in vaccine research and delivery. Nanovaccines, encompassing lipid and nonlipid formulations, exhibit considerable advantages over traditional vaccine techniques, including enhanced antigen stability, heightened immunogenicity, targeted distribution, and the potential for codelivery with adjuvants or immune modulators. This review provides a comprehensive overview of the latest advancements and applications of lipid and non-lipid-based nanovaccines in current vaccination strategies for immunization. The review commences by outlining the fundamental concepts underlying lipid and nonlipid nanovaccine design before delving into the diverse components and production processes employed in their development. Subsequently, a comparative analysis of various nanocarriers is presented, elucidating their distinct physicochemical characteristics and impact on the immune response, along with preclinical and clinical studies. The discussion also highlights how nanotechnology enables the possibility of personalized and combined vaccination techniques, facilitating the creation of tailored nanovaccines to meet the individual patient needs. The ethical aspects concerning the use of nanovaccines, as well as potential safety concerns and public perception, are also addressed. The study underscores the gaps and challenges that must be overcome before adopting nanovaccines in clinical practice. This comprehensive analysis offers vital new insights into lipid and nonlipid nanovaccine status. It emphasizes the significance of continuous research, collaboration among interdisciplinary experts, and regulatory measures to fully unlock the potential of nanotechnology in enhancing immunization and ensuring a healthier, more resilient society.

Curcumin and analogues in mitigating liver injury and disease consequences: From molecular mechanisms to clinical perspectives

BACKGROUND

Liver injury is a prevalent global health concern, impacting a substantial number of individuals and leading to elevated mortality rates and socioeconomic burdens. Traditional primary treatment options encounter resource constraints and high costs, prompting exploration of alternative adjunct therapies, such as phytotherapy. Curcumin demonstrates significant therapeutic potential across various medical conditions, particularly emerging as a promising candidate for liver injury treatment.

PURPOSE

This study aims to provide current evidence maps of curcumin and its analogs in the context of liver injury, covering aspects of biosafety, toxicology, and clinical trials. Importantly, it seeks to summarize the intricate mechanisms modulated by curcumin.

METHODS

We conducted a comprehensive search of MEDLINE, Web of Science, and Embase up to July 2023. Titles and abstracts were reviewed to identify studies that met our eligibility criteria. The screening process involved three authors independently assessing the potential of curcumin mitigating liver injury and its disease consequences by reviewing titles, abstracts, and full texts.

RESULTS

Curcumin and its analogs have demonstrated low toxicity in vitro and in vivo. However, the limited bioavailability has hindered their advanced use in liver injury. This limitation can potentially be addressed by nano-curcumin and emerging drug delivery systems. Curcumin plays a role in alleviating liver injury by modulating the antioxidant system, as well as cellular and molecular pathways. The specific mechanisms involve multiple pathways, such as NF-κB, p38/MAPK, and JAK2/STAT3, and the pro-apoptosis Bcl-2/Bax/caspase-3 axis in damaged cells. Additionally, curcumin targets nutritional metabolism, regulating the substance in liver cells and tissues. The microenvironment associated with liver injury, like extracellular matrix and immune cells and factors, is also regulated by curcumin. Initial evaluation of curcumin and its analogs through 12 clinical trials demonstrates their potential application in liver injury.

CONCLUSION

Curcumin emerges as a promising phytomedicine for liver injury owing to its effectiveness in hepatoprotection and low toxicity profile. Nevertheless, in-depth investigations are warranted to unravel the complex mechanisms through which curcumin influences liver tissues and overall physiological milieu. Moreover, extensive clinical trials are essential to determine optimal curcumin dosage forms, maximizing its benefits and achieving favorable clinical outcomes.

Liver-Targeting Nanoplatforms for the Induction of Immune Tolerance

Liver-targeting nanoparticles have emerged as a promising platform for the induction of immune tolerance by taking advantage of the liver's unique tolerogenic properties and nanoparticles' physicochemical flexibility. Such an approach provides a versatile solution to the treatment of a diversity of immunologic diseases. In this review, we begin by assessing the design parameters integral to cell-specific targeting and the tolerogenic induction of nanoplatforms engineered to target the four critical immunogenic hepatic cells, including liver sinusoidal epithelial cells (LSECs), Kupffer cells (KCs), hepatic stellate cells (HSCs), and hepatocytes. We also include an overview of multiple therapeutic strategies in which nanoparticles are being studied to treat many allergies and autoimmune disorders. Finally, we explore the challenges of using nanoparticles in this field while highlighting future avenues to expand the therapeutic utility of liver-targeting nanoparticles in autoimmune processes.

A Bone Targeting Nanoparticle Loaded OGP to Restore Bone Homeostasis for Osteoporosis Therapy

Restoring bone homeostasis is the key to the treatment of osteoporosis. How to increase osteogenic ability or inhibit osteoclast activity has always been a topic of great concern. In recent years, short peptides with biological activity have received great attention in bone repair. However, the application of short peptides is still limited due to the lack of a stable and targeted delivery system. Poly(lactic-co-glycolic acid) (PLGA) nanoparticles modified by alendronate (AL) to transport osteogenic peptides (OGP) (AL-PLGA@P NPs) are designed. Benefiting from the high affinity of AL for hydroxyapatite, AL-PLGA@P NPs have the ability to target bone. In this delivery system, OGP that promotes osteogenesis synergizes with AL, which inhibits osteoclasts, to regulate bone homeostasis, which gives them more advantages in the treatment of osteoporosis. The data shows that nanoparticles can selectively deliver peptides to the bone surface without systemic toxicity. Moreover, nanoparticles can upregulate osteogenesis-related factors (ALP, Runx-2, and BMP2) and downregulate osteoclast-related factors (TRAP and CTSK) in vitro. With AL-PLGA@P NPs, bone microarchitecture and bone mass are improved in ovariectomized osteoporosis rats. Therefore, this study proposes a novel osteoporosis-based drug system that effectively improves bone density.

Targeting macrophage M1 polarization suppression through PCAF inhibition alleviates autoimmune arthritis via synergistic NF-κB and H3K9Ac blockade

Sustained inflammatory invasion leads to joint damage and progressive disability in several autoimmune rheumatic diseases. In recent decades, targeting M1 macrophage polarization has been suggested as a promising therapeutic strategy for autoimmune arthritis. P300/CBP-associated factor (PCAF) is a histone acetyltransferase (HAT) that exhibits a strong positive relationship with the proinflammatory microenvironment. However, whether PCAF mediates M1 macrophage polarization remains poorly studied, and whether targeting PCAF can protect against autoimmune arthritis in vivo remains unclear. Commonly used drugs can cause serious side effects in patients because of their extensive and nonspecific distribution in the human body. One strategy for overcoming this challenge is to develop drug nanocarriers that target the drug to desirable regions and reduce the fraction of drug that reaches undesirable targets. In this study, we demonstrated that PCAF inhibition could effectively inhibit M1 polarization and alleviate arthritis in mice with collagen-induced arthritis (CIA) via synergistic NF-κB and H3K9Ac blockade. We further designed dextran sulfate (DS)-based nanoparticles (DSNPs) carrying garcinol (a PCAF inhibitor) to specifically target M1 macrophages in inflamed joints of the CIA mouse model via SR-A-SR-A ligand interactions. Compared to free garcinol, garcinol-loaded DSNPs selectively targeted M1 macrophages in inflamed joints and significantly improved therapeutic efficacy in vivo. In summary, our study indicates that targeted PCAF inhibition with nanoparticles might be a promising strategy for treating autoimmune arthritis via M1 macrophage polarization inhibition.

Liver Cell Type-Specific Targeting by Nanoformulations for Therapeutic Applications

Hepatocytes exert pivotal roles in metabolism, protein synthesis and detoxification. Non-parenchymal liver cells (NPCs), largely comprising macrophages, dendritic cells, hepatic stellate cells and liver sinusoidal cells (LSECs), serve to induce immunological tolerance. Therefore, the liver is an important target for therapeutic approaches, in case of both (inflammatory) metabolic diseases and immunological disorders. This review aims to summarize current preclinical nanodrug-based approaches for the treatment of liver disorders. So far, nano-vaccines that aim to induce hepatitis virus-specific immune responses and nanoformulated adjuvants to overcome the default tolerogenic state of liver NPCs for the treatment of chronic hepatitis have been tested. Moreover, liver cancer may be treated using nanodrugs which specifically target and kill tumor cells. Alternatively, nanodrugs may target and reprogram or deplete immunosuppressive cells of the tumor microenvironment, such as tumor-associated macrophages. Here, combination therapies have been demonstrated to yield synergistic effects. In the case of autoimmune hepatitis and other inflammatory liver diseases, anti-inflammatory agents can be encapsulated into nanoparticles to dampen inflammatory processes specifically in the liver. Finally, the tolerance-promoting activity especially of LSECs has been exploited to induce antigen-specific tolerance for the treatment of allergic and autoimmune diseases.

Translational Selenium Nanoparticles to Attenuate Allergic Dermatitis through Nrf2-Keap1-Driven Activation of Selenoproteins

Easy recurrence and strong treatment side effects significantly limit the clinical treatment of allergic dermatitis. The human trace element selenium (Se) plays essential roles in redox regulation through incorporation into selenoproteins in the form of 21st necessary amino acid selenocysteine, to participates in the pathogenesis and intervention of chronic inflammatory diseases. Therefore, based on the safe and elemental properties of Se, we construct a facile-synthesis strategy for antiallergic selenium nanoparticles (LET-SeNPs), and scale up the production by employing a spray drying method with lactose (Lac-LET-SeNPs) or maltodextrin (Mal-LET-SeNPs) as encapsulation agents realizing larger scale production and a longer storage time. As expected, these as-prepared LET-SeNPs could effectively activate the Nrf2-Keap1 signaling pathway to enhance the expression of antioxidative selenoprotein at mRNA and protein levels, then inhibit mast cell activation to achieve efficient antiallergic activity. Interestingly, LET-SeNPs undergo metabolism to seleno-amino acids to promote biosynthesis of selenoproteins, which could suppress ROS-induced cyclooxygenase-2 (COX-2) and MAPKs activation to suppress the release of histamine and inflammatory cytokines. Allergic mouse and Macaca fascicularis models further confirm that LET-SeNPs could increase the Se content and selenoprotein expression in the skin, decrease mast cells activation and inflammatory cells infiltration, and finally exhibit the high therapeutic effects on allergic dermatitis. Taken together, this study not only constructs facile large-scale synthesis of translational Se nanomedicine to break through the bottleneck problem of nanomaterials but also sheds light on its application in the intervention and treatment of allergies.

Counteracting Immunosenescence-Which Therapeutic Strategies Are Promising?

Aging attenuates the overall responsiveness of the immune system to eradicate pathogens. The increased production of pro-inflammatory cytokines by innate immune cells under basal conditions, termed inflammaging, contributes to impaired innate immune responsiveness towards pathogen-mediated stimulation and limits antigen-presenting activity. Adaptive immune responses are attenuated as well due to lowered numbers of naïve lymphocytes and their impaired responsiveness towards antigen-specific stimulation. Additionally, the numbers of immunoregulatory cell types, comprising regulatory T cells and myeloid-derived suppressor cells, that inhibit the activity of innate and adaptive immune cells are elevated. This review aims to summarize our knowledge on the cellular and molecular causes of immunosenescence while also taking into account senescence effects that constitute immune evasion mechanisms in the case of chronic viral infections and cancer. For tumor therapy numerous nanoformulated drugs have been developed to overcome poor solubility of compounds and to enable cell-directed delivery in order to restore immune functions, e.g., by addressing dysregulated signaling pathways. Further, nanovaccines which efficiently address antigen-presenting cells to mount sustained anti-tumor immune responses have been clinically evaluated. Further, senolytics that selectively deplete senescent cells are being tested in a number of clinical trials. Here we discuss the potential use of such drugs to improve anti-aging therapy.

Treatment of food allergy: Oral immunotherapy, biologics, and beyond

The prevalence of food allergy (FA) has been increasing globally and comes with a heavy burden not just economically, but also on quality of life. Although oral immunotherapy (OIT) is effective at inducing desensitization to food allergens, it has several limitations that weaken its success. Limitations include a long duration of build-up, especially when used for multiple allergens, and a high rate of reported adverse events. Furthermore, OIT may not be effective in all patients. Efforts are underway to identify additional treatment options, either as monotherapy or in combination, to treat FA or enhance the safety and efficacy of OIT. Biologics such as omalizumab and dupilumab, which already have US Food and Drug Administration approval for other atopic conditions have been the most studied, but additional biologics and novel strategies are emerging. In this review, we discuss therapeutic strategies including immunoglobulin E inhibitors, immunoglobulin E disruptors, interleukin-4 and interleukin-13 inhibitors, antialarmins, JAK1 and BTK inhibitors, and nanoparticles, and the data surrounding their application in FA and highlighting their potential.

mRNA lipid nanoparticles induce immune tolerance to treat human diseases

Rapid developments in the coronavirus disease 2019 (COVID-19) mRNA vaccine showcased the power of lipid nanoparticle (LNP) delivery systems in fighting infectious diseases. In addition, mRNA therapeutics are also in development for cancer immunotherapy. Recently, mRNA therapy has been expanded to induce immune tolerance, the opposite of immune-boosting effects, to treat diseases involving enhanced immune responses including allergies and autoimmune diseases. mRNA LNPs have been used to treat peanut allergy by us and autoimmune experimental autoimmune encephalomyelitis by Ugur Sahin. It is expected that more and more research is going to delve into the immune tolerance field for allergies and autoimmune diseases, where effective therapies are in short supply.

Use of a Liver-Targeting Immune-Tolerogenic mRNA Lipid Nanoparticle Platform to Treat Peanut-Induced Anaphylaxis by Single- and Multiple-Epitope Nucleotide Sequence Delivery

While oral desensitization is capable of alleviating peanut allergen anaphylaxis, long-term immune tolerance is the sought-after goal. We developed a liver-targeting lipid nanoparticle (LNP) platform to deliver mRNA-encoded peanut allergen epitopes to liver sinusoidal endothelial cells (LSECs), which function as robust tolerogenic antigen-presenting cells that induce FoxP3+ regulatory T-cells (Tregs). The mRNA strand was constructed by including nucleotide sequences encoding for nonallergenic MHC-II binding T-cell epitopes, identified in the dominant peanut allergen, Ara h2. These epitopes were inserted in the mRNA strand downstream of an MHC-II targeting sequence, further endowed in vitro with 5' and 3' capping sequences, a PolyA tail, and uridine substitution. Codon-optimized mRNA was used for microfluidics synthesis of LNPs with an ionizable cationic lipid, also decorated with a lipid-anchored mannose ligand for LSEC targeting. Biodistribution to the liver was confirmed by in vivo imaging, while ELISpot assays demonstrated an increase in IL-10-producing Tregs in the spleen. Prophylactic administration of tandem-repeat or a combination of encapsulated Ara h2 epitopes induced robust tolerogenic effects in C3H/HeJ mice, sensitized to and subsequently challenged with crude peanut allergen extract. In addition to alleviating physical manifestations of anaphylaxis, there was suppression of Th2-mediated cytokine production, IgE synthesis, and mast cell release, accompanied by increased IL-10 and TGF-β production in the peritoneum. Similar efficacy was demonstrated during LNP administration postsensitization. While nondecorated particles had lesser but significant effects, PolyA/LNP-Man lacked protective effects. These results demonstrate an exciting application of mRNA/LNP for treatment of food allergen anaphylaxis, with the promise to be widely applicable to the allergy field.

Biomaterial Strategies for Selective Immune Tolerance: Advances and Gaps

Autoimmunity and allergies affect a large number of people across the globe. Current approaches to these diseases target cell types and pathways that drive disease, but these approaches are not cures and cannot differentiate between healthy cells and disease-causing cells. New immunotherapies that induce potent and selective antigen-specific tolerance is a transformative goal of emerging treatments for autoimmunity and serious allergies. These approaches offer the potential of halting-or even reversing-disease, without immunosuppressive side effects. However, translating successful induction of tolerance to patients is unsuccessful. Biomaterials offer strategies to direct and maximize immunological mechanisms of tolerance through unique capabilities such as codelivery of small molecules or signaling molecules, controlling signal density in key immune tissues, and targeting. While a growing body of work in this area demonstrates success in preclinical animal models, these therapies are only recently being evaluated in human trials. This review will highlight the most recent advances in the use of materials to achieve antigen-specific tolerance and provide commentary on the current state of the clinical development of these technologies.

Tissue-Targeted Drug Delivery Strategies to Promote Antigen-Specific Immune Tolerance

During autoimmunity or organ transplant rejection, the immune system attacks host or transplanted tissue, causing debilitating inflammation for millions of patients. There is no cure for most of these diseases. Further, available therapies modulate inflammation through nonspecific pathways, reducing symptoms but also compromising patients' ability to mount healthy immune responses. Recent preclinical advances to regulate immune dysfunction with vaccine-like antigen specificity reveal exciting opportunities to address the root cause of autoimmune diseases and transplant rejection. Several of these therapies are currently undergoing clinical trials, underscoring the promise of antigen-specific tolerance. Achieving antigen-specific tolerance requires precision and often combinatorial delivery of antigen, cytokines, small molecule drugs, and other immunomodulators. This can be facilitated by biomaterial technologies, which can be engineered to orient and display immunological cues, protect against degradation, and selectively deliver signals to specific tissues or cell populations. In this review, some key immune cell populations involved in autoimmunity and healthy immune tolerance are described. Opportunities for drug delivery to immunological organs are discussed, where specialized tissue-resident immune cells can be programmed to respond in unique ways toward antigens. Finally, cell- and biomaterial-based therapies to induce antigen-specific immune tolerance that are currently undergoing clinical trials are highlighted.

Transcytosis-enabled active extravasation of tumor nanomedicine

Extravasation is the first step for nanomedicines in circulation to reach targeted solid tumors. Traditional nanomedicines have been designed to extravasate into tumor interstitium through the interendothelial gaps previously assumed rich in tumor blood vessels, i.e., the enhanced permeability and retention (EPR) effect. While the EPR effect has been validated in animal xenograft tumor models, accumulating evidence implies that the EPR effect is very limited and highly heterogeneous in human tumors, leading to highly unpredictable and inefficient extravasation and thus limited therapeutic efficacy of nanomedicines, including those approved in clinics. Enabling EPR-independent extravasation is the key to develop new generation of nanomedicine with enhanced efficacy. Transcytosis of tumor endothelial cells can confer nanomedicines to actively extravasate into solid tumors without relying on the EPR effect. Here, we review and prospectthe development of transcytosis-inducing nanomedicines, in hope of providing instructive insights for design of nanomedicines that can undergo selective transcellular transport across tumor endothelial cells, and thus inspiring the development of next-generation nanomedicines for clinical translation.

The Crosstalk Between Liver Sinusoidal Endothelial Cells and Hepatic Microenvironment in NASH Related Liver Fibrosis

Chronic liver injury can be caused by many factors, including virus infection, alcohol intake, cholestasis and abnormal fat accumulation. Nonalcoholic steatohepatitis (NASH) has become the main cause of liver fibrosis worldwide. Recently, more and more evidences show that hepatic microenvironment is involved in the pathophysiological process of liver fibrosis induced by NASH. Hepatic microenvironment consists of various types of cells and intercellular crosstalk among different cells in the liver sinusoids. Liver sinusoidal endothelial cells (LSECs), as the gatekeeper of liver microenvironment, play an irreplaceable role in the homeostasis and alterations of liver microenvironment. Many recent studies have reported that during the progression of NASH to liver fibrosis, LSECs are involved in various stages mediated by a series of mechanisms. Therefore, here we review the key role of crosstalk between LSECs and hepatic microenvironment in the progression of NASH to liver fibrosis (steatosis, inflammation, and fibrosis), as well as promising therapeutic strategies targeting LSECs.

Enrichment Methods for Murine Liver Non-Parenchymal Cells Differentially Affect Their Immunophenotype and Responsiveness towards Stimulation

Hepatocytes comprise the majority of the liver and largely exert metabolic functions, whereas non-parenchymal cells (NPCs)—comprising Kupffer cells, dendritic cells and liver sinusoidal endothelial cells—control the immunological state within this organ. Here, we compared the suitability of two isolation methods for murine liver NPCs. Liver perfusion (LP) with collagenase/DNase I applied via the portal vein leads to efficient liver digestion, whereas the modified liver dissociation (LD) method combines mechanical dissociation of the retrieved organ with enzymatic degradation of the extracellular matrix. In cases of both LP and LD, NPCs were enriched by subsequent gradient density centrifugation. Our results indicate that LP and LD are largely comparable with regards to the yield, purity, and composition of liver NPCs. However, LD-enriched liver NPCs displayed a higher degree of activation after overnight cultivation, and accordingly were less responsive towards stimulation with toll-like receptor ligands that are frequently used as adjuvants, e.g., in nano-vaccines. We conclude that LP is more suitable for obtaining liver NPCs for subsequent in vitro studies, whereas LD as the less laborious method, is more convenient for parallel isolation of larger numbers of samples for ex vivo analysis.

Harnessing the liver to induce antigen-specific immune tolerance

Autoimmune diseases develop when the adaptive immune system attacks the body’s own antigens leading to tissue damage. At least 80 different conditions are believed to have an autoimmune aetiology, including rheumatoid arthritis, type I diabetes, multiple sclerosis or systemic lupus erythematosus. Collectively, autoimmune diseases are a leading cause of severe health impairment along with substantial socioeconomic costs. Current treatments are mostly symptomatic and non-specific, and it is typically not possible to cure these diseases. Thus, the development of more causative treatments that suppress only the pathogenic immune responses, but spare general immunity is of great biomedical interest. The liver offers considerable potential for development of such antigen-specific immunotherapies, as it has a distinct physiological capacity to induce immune tolerance. Indeed, the liver has been shown to specifically suppress autoimmune responses to organ allografts co-transplanted with the liver or to autoantigens that were transferred to the liver. Liver tolerance is established by a unique microenvironment that facilitates interactions between liver-resident antigen-presenting cells and lymphocytes passing by in the low blood flow within the hepatic sinusoids. Here, we summarise current concepts and mechanisms of liver immune tolerance, and review present approaches to harness liver tolerance for antigen-specific immunotherapy.

Therapeutic role of curcumin in adult neurogenesis for management of psychiatric and neurological disorders: a scientometric study to an in-depth review

Aberrant neurogenesis is a major factor in psychiatric and neurological disorders that have significantly attracted the attention of neuroscientists. Curcumin is a primary constituent of curcuminoid that exerts several positive pharmacological effects on aberrant neurogenesis. First, it is important to understand the different processes of neurogenesis, and whether their dysfunction promotes etiology as well as the development of many psychiatric and neurological disorders; then investigate mechanisms by which curcumin affects neurogenesis as an active participant in pathophysiological events. Based on scientometric studies and additional extensive research, we explore the mechanisms by which curcumin regulates adult neurogenesis and in turn affects psychiatric diseases, i.e., depression and neurological disorders among them traumatic brain injury (TBI), stroke, Alzheimer's disease (AD), Gulf War Illness (GWI) and Fragile X syndrome (FXS). This review aims to elucidate the therapeutic effects and mechanisms of curcumin on adult neurogenesis in various psychiatric and neurological disorders. Specifically, we discuss the regulatory role of curcumin in different activities of neural stem cells (NSCs), including proliferation, differentiation, and migration of NSCs. This is geared toward providing novel application prospects of curcumin in treating psychiatric and neurological disorders by regulating adult neurogenesis.

Multifunctional Lipid Bilayer Nanocarriers for Cancer Immunotherapy in Heterogeneous Tumor Microenvironments, Combining Immunogenic Cell Death Stimuli with Immune Modulatory Drugs

In addition to the contribution of cancer cells, the solid tumor microenvironment (TME) has a critical role in determining tumor expansion, antitumor immunity, and the response to immunotherapy. Understanding the details of the complex interplay between cancer cells and components of the TME provides an unprecedented opportunity to explore combination therapy for intervening in the immune landscape to improve immunotherapy outcome. One approach is the introduction of multifunctional nanocarriers, capable of delivering drug combinations that provide immunogenic stimuli for improvement of tumor antigen presentation, contemporaneous with the delivery of coformulated drug or synthetic molecules that provide immune danger signals or interfere in immune-escape, immune-suppressive, and T-cell exclusion pathways. This forward-looking review will discuss the use of lipid-bilayer-encapsulated liposomes and mesoporous silica nanoparticles for combination immunotherapy of the heterogeneous immune landscapes in pancreatic ductal adenocarcinoma and triple-negative breast cancer. We describe how the combination of remote drug loading and lipid bilayer encapsulation is used for the synthesis of synergistic drug combinations that induce immunogenic cell death, interfere in the PD-1/PD-L1 axis, inhibit the indoleamine-pyrrole 2,3-dioxygenase (IDO-1) immune metabolic pathway, restore spatial access to activated T-cells to the cancer site, or reduce the impact of immunosuppressive stromal components. We show how an integration of current knowledge and future discovery can be used for a rational approach to nanoenabled cancer immunotherapy.

Nanoparticles for Inducing Antigen-Specific T Cell Tolerance in Autoimmune Diseases

Autoimmune diseases affect many people worldwide. Current treatment modalities focus on the reduction of disease symptoms using anti-inflammatory drugs which can lead to side effects due to systemic immune suppression. Restoration of immune tolerance by down-regulating auto-reactive cells in an antigen-specific manner is currently the “holy grail” for the treatment of autoimmune diseases. A promising strategy is the use of nanoparticles that can deliver antigens to antigen-presenting cells which in turn can enhance antigen-specific regulatory T cells. In this review, we highlight some promising cell targets (e.g. liver sinusoidal endothelial cells and splenic marginal zone macrophages) for exploiting natural immune tolerance processes, and several strategies by which antigen-carrying nanoparticles can target these cells. We also discuss how nanoparticles carrying immunomodulators may be able to activate tolerance in other antigen-presenting cell types. Finally, we discuss some important aspects that must be taken into account when translating data from animal studies to patients.

Understanding Nanomaterial-Liver Interactions to Facilitate the Development of Safer Nanoapplications

Nanomaterials (NMs) are widely used in commercial and medical products, such as cosmetics, vaccines, and drug carriers. Exposure to NMs via various routes such as dermal, inhalation, and ingestion has been shown to gain access to the systemic circulation, resulting in the accumulation of NMs in the liver. The unique organ structures and blood flow features facilitate the liver sequestration of NMs, which may cause adverse effects in the liver. Currently, most in vivo studies are focused on NMs accumulation at the organ level and evaluation of the gross changes in liver structure and functions, however, cell-type-specific uptake and responses, as well as the molecular mechanisms at cellular levels leading to effects at organ levels are lagging. Herein, the authors systematically review diverse interactions of NMs with the liver, specifically on major liver cell types including Kupffer cells (KCs), liver sinusoidal endothelial cells (LSECs), hepatic stellate cells (HSCs), and hepatocytes as well as the detailed molecular mechanisms involved. In addition, the knowledge gained on nano-liver interactions that can facilitate the development of safer nanoproducts and nanomedicine is also reviewed.

Use of a Liver-targeting Nanoparticle Platform to Intervene in Peanut-induced anaphylaxis through delivery of an Ara h2 T-cell Epitope

To address the urgent need for safe food allergen immunotherapy, we have developed a liver-targeting nanoparticle platform, capable of intervening in allergic inflammation, mast cell release and anaphylaxis through the generation of regulatory T-cells (Treg). In this communication, we demonstrate the use of a poly (lactide-co-glycolide acid) (PLGA) nanoparticle platform for intervening in peanut anaphylaxis through the encapsulation and delivery of a dominant protein allergen, Ara h 2 and representative T-cell epitopes, to liver sinusoidal endothelial cells (LSECs). These cells have the capacity to act as natural tolerogenic antigen-presenting cells (APC), capable of Treg generation by T-cell epitope presentation by histocompatibility (MHC) type II complexes on the LSEC surface. This allowed us to address the hypothesis that the tolerogenic nanoparticles platform could be used as an effective, safe, and scalable intervention for suppressing anaphylaxis to crude peanut allergen extract. Following the analysis of purified Ara h 2 and representative MHC-II epitopes Treg generation in vivo, a study was carried out to compare the best-performing Ara h 2 T-cell epitope with a purified Ara h 2 allergen, a crude peanut protein extract (CPPE) and a control peptide in an oral sensitization model. Prophylactic as well as post-sensitization administration of the dominant encapsulated Ara h 2 T-cell epitope was more effective than the purified Ara h2 in eliminating anaphylactic manifestations, hypothermia, and mast cell protease release in a frequently used peanut anaphylaxis model. This was accompanied by decreased peanut-specific IgE blood levels and increased TGF-β release in the abdominal cavity. The duration of the prophylactic effect was sustained for two months. These results demonstrate that targeted delivery of carefully selected T-cell epitopes to natural tolerogenic liver APC could serve as an effective platform for the treatment of peanut allergen anaphylaxis.

Tuning surface charges of peptide nanofibers for induction of antigen-specific immune tolerance: an introductory study

Induction of antigen-specific immune tolerance has emerged as the next frontier in treating autoimmune disorders, including atherosclerosis and graft-vs-host reactions during transplantation. Nanostructures are under investigation as a platform for the coordinated delivery of critical components, i.e., the antigen epitope combined with tolerogenic agents, to the target immune cells and subsequently induce tolerance. In the present study, the utility of supramolecular peptide nanofibers to induce antigen-specific immune tolerance was explored. To study the influence of surface charges of the nanofibers towards the extent of the induced immune response, the flanking charge residues at both ends of the amphipathic fibrillization peptide sequences were varied. Dexamethasone, an immunosuppressive glucocorticoid drug, and the ovalbumin-derived OVA323-339 peptide that binds to I-A(d) MHC Class II were covalently linked at either end of the peptide sequences. It was shown that the functional extensions did not alter the structural integrity of the supramolecular nanofibers. Furthermore, the surface charges of the nanofibers were modulated by the inclusion of charged residues. Dendritic cell culture assays suggested that nanofiber of less negative ζ-potential can augment the antigen-specific tolerogenic response. Our findings illustrate a molecular approach to calibrate the tolerogenic response induced by peptide nanofibers, which pave the way for better design of future tolerogenic immunotherapies.

Nanotechnology in Drug Delivery for Liver Fibrosis

Liver fibrosis is a reversible disease course caused by various liver injury etiologies, and it can lead to severe complications, such as liver cirrhosis, liver failure, and even liver cancer. Traditional pharmacotherapy has several limitations, such as inadequate therapeutic effect and side effects. Nanotechnology in drug delivery for liver fibrosis has exhibited great potential. Nanomedicine improves the internalization and penetration, which facilitates targeted drug delivery, combination therapy, and theranostics. Here, we focus on new targets and new mechanisms in liver fibrosis, as well as recent designs and development work of nanotechnology in delivery systems for liver fibrosis treatment.

New Therapeutic Approaches for Allergy: A Review of Cell Therapy and Bio- or Nano-Material-Based Strategies

Allergy constitutes a major health issue due to its large prevalence. The established therapeutic approaches (allergen avoidance, antihistamines, and corticosteroids) do not address the underlying causes of the pathology, highlighting the need for other long-term treatment options. Antigen-specific immunotherapy enables the long-term control of allergic diseases by promoting immunological tolerance to the allergen. However, efficacious immunotherapies are not available for all possible allergens, and the risk of undesired reactions during therapy remains a concern, especially in patients with severe allergic reactions. In this context, two types of therapeutic strategies appear especially promising for the future in the context of allergy: cell therapy and bio- or nano-material-based therapy. In this review, the main strategies developed this far in these two types of strategies are discussed, with several examples illustrating the different approaches.

The ancillary effects of nanoparticles and their implications for nanomedicine

Nanoparticles are often engineered as a scaffolding system to combine targeting, imaging and/or therapeutic moieties into a unitary agent. However, mostly overlooked, the nanomaterial itself interacts with biological systems exclusive of application-specific particle functionalization. This nanoparticle biointerface has been found to elicit specific biological effects, which we term 'ancillary effects'. In this Review, we describe the current state of knowledge of nanobiology gleaned from existing studies of ancillary effects with the objectives to describe the potential of nanoparticles to modulate biological effects independently of any engineered function; evaluate how these effects might be relevant for nanomedicine design and functional considerations, particularly how they might be useful to inform clinical decision-making; identify potential clinical harm that arises from adverse nanoparticle interactions with biology; and, finally, highlight the current lack of knowledge in this area as both a barrier and an incentive to the further development of nanomedicine.