Alginate Microspheres Elicit Innate M1-Inflammatory Response in Macrophages Leading to Bacillary Killing

A Sodium Alginate-Based Multifunctional Nanoplatform for Synergistic Chemo-Immunotherapy of Hepatocellular Carcinoma

Efficient hepatocellular carcinoma (HCC) treatment remains a significant challenge due to the inherent limitations of traditional strategies. The exploration of polysaccharides' natural immunity for HCC immunotherapy is rarely explored. For this purpose, facile construction of a multifunctional nanoplatform, biotinylated aldehyde alginate-doxorubicin nano micelle (BEACNDOXM) is reported in this study for synergistic chemo-immunotherapy by using constant β-D-mannuronic acid (M) units and modulated α-L-guluronic acid (G) units in the alginate (ALG) structure. The M units show natural immunity and specific binding ability with mannose receptors (MRs) via strong receptor-ligand interactions, and the G units serve as highly reactive conjugation sites for biotin (Bio) and DOX. Therefore, this formulation not only integrates the natural immunity of ALG and the immunogenic cell death (ICD) triggering function of DOX, but also shows dual targeting properties to HCC cells via MRs and Bio receptors (BRs)-mediated endocytosis. Notably, BEACNDOXM mediates a tumor inhibitory efficiency 12.10% and 4.70% higher than free DOX and single targeting aldehyde alginate-doxorubicin nano micelle controls, respectively, at an equivalent DOX dose of 3 mg kg-1 in Hepa1-6 tumor-bearing mice. This study reports the first example of integrating the natural immunity of ALG and the ICD effect of anticancer drugs for enhanced chemo-immunotherapy of HCC.

Anisotropic, Hydrogel Microparticles as pH-Responsive Drug Carriers for Oral Administration of 5-FU

In the last 20 years, the development of stimuli-responsive drug delivery systems (DDS) has received great attention. Hydrogel microparticles represent one of the candidates with the most potential. However, if the role of the cross-linking method, polymer composition, and concentration on their performance as DDS has been well-studied, still, a lot needs to be explained regarding the effect caused by the morphology. To investigate this, herein, we report the fabrication of PEGDA-ALMA-based microgels with spherical and asymmetric shapes for 5-fluorouracil (5-FU) on-demand loading and in vitro pH-triggered release. Due to anisotropic properties, the asymmetric particles showed an increased drug adsorption and higher pH responsiveness, which in turn led to a higher desorption efficacy at the target pH environment, making them an ideal candidate for oral administration of 5-FU in colorectal cancer. The cytotoxicity of empty spherical microgels was higher than the cytotoxicity of empty asymmetric microgels, suggesting that the gel network's mechanical proprieties of anisotropic particles were a better three-dimensional environment for the vital functions of cells. Upon treatment with drug-loaded microgels, the HeLa cells' viability was lower after incubation with asymmetric particles, confirming a minor release of 5-FU from spherical particles.

Systems pharmacology reveals the mechanism of Astragaloside IV in improving immune activity on cyclophosphamide-induced immunosuppressed mice

ETHNOPHARMACOLOGICAL RELEVANCE

Myelosuppression, also known as bone marrow suppression (BMS), is a pathological phenomenon of the decrease in the production of blood cells and further lead to immune homeostasis disorder. Astragalus mongholicus Bunge (AM, checked with The World Flora Online, http://www.worldfloraonline.org, updated on January 30, 2023) is a traditional Chinese medicine with efficacy of tonifying Qi and strengthening body immunity in thousands of years of clinical practice in China. Astragaloside IV (AS-IV) is a major active ingredient of AM, which plays an important role in regulating immune system through different ways.

AIM OF THE STUDY

This study was aimed to investigate the protective effect and mechanism of AS-IV on macrophages in vitro and cyclophosphamide (CTX)-induced immunosuppressive mice in vivo, and to provide experimental basis for the prevention and treatment of AS-IV in myelosuppression.

MATERIALS AND METHODS

Based on network pharmacology and molecular docking technology, the core targets and signaling pathways of saponins of AM against myelosuppression were screened. And then, the immunoregulatory effect of AS-IV on RAW264.7 cells was investigated by cellular immune activity and cellular secretion analysis in vitro. In this way, the effects of AS-IV on the main potential targets of HIF-1α/NF-κB signaling pathway were analyzed by qRT-PCR and Western blot methods. Furthermore, comprehensive analysis of the effects of AS-IV against CTX-induced mice were conducted on the basis of immune organs indices analysis, histopathological analysis, hematological analysis, natural killer cell activity analysis and spleen lymphocyte transformation activity analysis. In order to further verify the relationship between active ingredients and action targets, drug inhibitor experiments were finally conducted.

RESULTS

AS-IV, as a potential anti-myelosuppressive compound, was screened by systematic pharmacological methods to act on target genes including HIF1A and RELA together with the HIF-1α/NF-κB signaling pathway. Further studies by molecular docking technology showed that AS-IV had good binding activity with HIF1A, RELA, TNF, IL6, IL1B and other core targets. Besides, cellular and animal experiments validation results showed that AS-IV could enhance the migration and phagocytosis of RAW264.7 cells, and protect the immune organs such as spleen and thymus together with bone tissues from damage. By this means, immune cell function including spleen natural killer cell and lymphocyte transformation activity were also enhanced. In addition, white blood cells, red blood cells, hemoglobin, platelets and bone marrow cells were also significantly improved in the suppressed bone marrow microenvironment (BMM). In kinetic experiments, the secretion of cytokines such as TNF-α, IL-6 and IL-1β were increased, and IL-10, TGF-β1 were decreased. The key regulatory proteins such as HIF-1α, NF-κB, PHD3 in HIF-1α/NF-κB signaling pathway were also regulated in the results of upregulated expression of HIF-1α, p-NF-κB p65 and PHD3 at the protein or mRNA level. Finally, the inhibition experiment results suggested that AS-IV could significantly improve protein response in immunity and inflammation such as HIF-1α, NF-κB and PHD3.

CONCLUSION

AS-IV could significantly relieve CTX-induced immunosuppressive and might improve the immune activity of macrophages by activating HIF-1α/NF-κB signaling pathway, and provide a reliable basis for the clinical application of AS-IV as a potentially valuable regulator of BMM.

Pulmonary drug delivery applications of natural polysaccharide polymer derived nano/micro-carrier systems: A review

Respiratory distress syndrome and pneumothorax are the foremost causes of death as a result of the changing lifestyle and increasing air pollution. Numerous approaches have been studied for the pulmonary delivery of drugs, proteins as well as peptides using meso/nanoparticles, nanocrystals, and liposomes. These nano/microcarrier systems (NMCs) loaded with drug provide better systemic as well as local action. Furthermore, natural polysaccharide-based polymers such as chitosan (CS), alginate (AG), hyaluronic acid, dextran, and cellulose are highly used for the preparation of nanoparticles and delivery of the drug into the pulmonary tract due to their advantageous properties such as low toxicity, high hydrophobicity, supplementary mucociliary clearance, mucoadhesivity, and biological efficacy. These properties ease the delivery of drugs onto the targeted site. Herein, recent advances in the natural polymer-derived NMCs have been reviewed for their transport and mechanism of action into the bronchiolar region as well as the respiratory region. Various physicochemical properties such as surface charge, size of nanocarrier system, surface modifications, and toxicological effects of these nanocarriers in vitro and in vivo are elucidated as well. Furthermore, challenges faced for the preparation of a model NMCs for pulmonary drug delivery are also discoursed.

The role of neuroplastin65 in macrophage against E. coli infection in mice

BACKGROUND

Innate immune response constitutes the first line of defense against pathogens. Inflammatory responses involve close contact between different populations of cells. These adhesive interactions mediate migration of cells to sites of infection leading the effective action of cells within the lesions. Cell adhesion molecules are critical to controlling immune response mediating cell adhesion or chemotaxis, as well as coordinating actin-based cell motility during phagocytosis and chemotaxis. Recently, a newly discovered neuroplastin (Np) adhesion molecule is found to play an important role in the nervous system. However, there is limited information on Np functions in immune response. To understand how Np is involved in innate immune response, a mouse model of intraperitoneal infection was established to investigate the effect of Np on macrophage-mediated clearance of E. coli infection and its possible molecular mechanisms.

METHODS

Specific deficiency mice with Nptn gene controlling Np65 isoform were employed in this study. The expression levels of mRNA and proteins were detected by qPCR and western blot, or evaluated by flow cytometry. The expression level of NO and ROS were measured with their specific indicators. Cell cycle and apoptosis were detected by specific detection kits. Acid phosphatase activity was measured by flow cytometry after labelling with LysoRed fluorescent probe. Bone marrow derived macrophages (BMDMs) were isolated from bone marrow of mice hind legs. Cell proliferation was detected by CCK8 assay. Cell migration was measured by wound healing assay or transwell assay.

RESULTS

The lethal dose of E. coli infection in Np65^-/- mice dropped to the half of lethal dose in WT mice. The bacterial load in the spleen, kidney and liver from Np65^-/- mice were significantly higher than that from WT mice, which were due to the dramatic reduction of NO and ROS production in phagocytes from Np65^-/- mice. Np65 gene deficiency remarkably impaired phagocytosis and function of lysosome in macrophage. Furthermore, Np65 molecule was involved in maturation and proliferation, even in migration and chemotaxis of BMDM in vitro.

CONCLUSION

This study for the first time demonstrates that Np is involved in multi-function of phagocytes during bacterial infection, proposing that Np adhesion molecule plays a critical role in clearing pathogen infection in innate immunity.

Meta-Analysis of Drug Delivery Approaches for Treating Intracellular Infections

This meta-analysis aims to evaluate the trend, methodological quality and completeness of studies on intracellular delivery of antimicrobial agents. PubMed, Embase, and reference lists of related reviews were searched to identify original articles that evaluated carrier-mediated intracellular delivery and pharmacodynamics (PD) of antimicrobial therapeutics against intracellular pathogens in vitro and/or in vivo. A total of 99 studies were included in the analysis. The most commonly targeted intracellular pathogens were bacteria (62.6%), followed by viruses (16.2%) and parasites (15.2%). Twenty-one out of 99 (21.2%) studies performed neither microscopic imaging nor flow cytometric analysis to verify that the carrier particles are present in the infected cells. Only 31.3% of studies provided comparative inhibitory concentrations against a free drug control. Approximately 8% of studies, albeit claimed for intracellular delivery of antimicrobial therapeutics, did not provide any experimental data such as microscopic imaging, flow cytometry, and in vitro PD. Future research on intracellular delivery of antimicrobial agents needs to improve the methodological quality and completeness of supporting data in order to facilitate clinical translation of intracellular delivery platforms for antimicrobial therapeutics.

A γ-PGA/KGM-based injectable hydrogel as immunoactive and antibacterial wound dressing for skin wound repair

Injectable hydrogels, of which the cover area and volume can be flexibly adjusted according to the shape and depth of the wound, are considered to be an ideal material for wound dressing. Konjac glucomannan (KGM) is a natural polysaccharide with immunomodulatory capability, while γ-polyglutamic acid (γ-PGA) is a single chain polyamino acid with moisturizing, water-retention and antibacterial properties. This work intended to combine the advantages of the two materials to prepare an injectable hydrogel (P-OK) by mixing the adipic acid dihydrazide (ADH) modified γ-PGA with oxidized KGM. The chemical structures, the physical and chemical properties, and the biological properties of the P-OK hydrogel were evaluated. The optimal conditions to form the P-OK hydrogel were fixed, and the cytotoxicity, qPCR, antibacterial and animal experiments were performed. Results showed that the P-OK hydrogel had a fast gelation time, good water-retention rate, little cytotoxicity, good immunomodulating and antibacterial capabilities, and could shorten the healing period in the rat full-thickness defect model, which makes it a potential candidate for wound repair dressing.

The Influence of Polysaccharides-Based Material on Macrophage Phenotypes

Macrophage polarization is a key factor in determining the success of implanted tissue engineering scaffolds. Polysaccharides (derived from plants, animals, and microorganisms) are known to modulate macrophage phenotypes by recognizing cell membrane receptors. Numerous studies have developed polysaccharide-based materials into functional biomaterial substrates for tissue regeneration and pharmaceutical application due to their immunostimulatory activities and anti-inflammatory response. They are used as hydrogel substrates, surface coatings, and drug delivery carriers. In addition to their innate immunological functions, the newly endowed physical and chemical properties, including substrate modulus, pore size/porosity, surface binding chemistry, and the mole ratio of polysaccharides in hybrid materials may regulate macrophage phenotypes more precisely. Growing evidence indicates that the sulfation pattern of glycosaminoglycans and proteoglycans expressed on polarized macrophages leads to the changes in protein binding, which may alter macrophage phenotype and influence the immune response. A comprehensive understanding of how different types of polysaccharide-based materials alter macrophage phenotypic changes can be beneficial to predict transplantation/implantation outcomes. This review focuses on recent advances in promoting wound healing and balancing macrophage phenotypes using polysaccharide-based substrates/coatings and new directions to address the limitations in the current understanding of macrophage responses to polysaccharides.

Formulation of host-targeted therapeutics against bacterial infections

The global burden of bacterial infections is rising due to increasing resistance to the majority of first-line antibiotics, rendering these drugs ineffective against several clinically important pathogens. Limited transport of antibiotics into cells compounds this problem for gram-negative bacteria that exhibit prominent intracellular lifecycles. Furthermore, poor bioavailability of antibiotics in infected tissues necessitates higher doses and longer treatment regimens to treat resistant infections. Although emerging antibiotics can combat these problems, resistance still may develop over time. Expanding knowledge of host-pathogen interactions has inspired research and development of host-directed therapies (HDTs). HDTs target host-cell machinery critical for bacterial pathogenesis to treat bacterial infections alone or as adjunctive treatment with traditional antibiotics. Unlike traditional antibiotics that directly affect bacteria, a majority of HDTs function by boosting the endogenous antimicrobial activity of cells and are consequently less prone to bacterial tolerance induced by selection pressure. Therefore, HDTs can be quite effective against intracellular cytosolic or vacuolar bacteria, which a majority of traditional antibiotics are unable to eradicate. However, in vivo therapeutic efficacy of HDTs is reliant on adequate bioavailability. Particle-based formulations demonstrate the potential to enable targeted drug delivery, enhance cellular uptake, and increase drug concentration in the host cell of HDTs. This review selected HDTs for clinically important pathogens, identifies formulation strategies that can improve their therapeutic efficacy and offers insights toward further development of HDTs for bacterial infections.

Immunomodulation as a Novel Strategy for Prevention and Treatment of Bordetella spp. Infections

Well-adapted pathogens have evolved to survive the many challenges of a robust immune response. Defending against all host antimicrobials simultaneously would be exceedingly difficult, if not impossible, so many co-evolved organisms utilize immunomodulatory tools to subvert, distract, and/or evade the host immune response. Bordetella spp. present many examples of the diversity of immunomodulators and an exceptional experimental system in which to study them. Recent advances in this experimental system suggest strategies for interventions that tweak immunity to disrupt bacterial immunomodulation, engaging more effective host immunity to better prevent and treat infections. Here we review advances in the understanding of respiratory pathogens, with special focus on Bordetella spp., and prospects for the use of immune-stimulatory interventions in the prevention and treatment of infection.