Recruitment of bone marrow CD11b+Gr-1+ cells by polymeric nanoparticles for antigen cross-presentation

Exploring and Analyzing the Systemic Delivery Barriers for Nanoparticles

Most nanomedicines require efficient in vivo delivery to elicit diagnostic and therapeutic effects. However, en route to their intended tissues, systemically administered nanoparticles often encounter delivery barriers. To describe these barriers, we propose the term "nanoparticle blood removal pathways" (NBRP), which summarizes the interactions between nanoparticles and the body's various cell-dependent and cell-independent blood clearance mechanisms. We reviewed nanoparticle design and biological modulation strategies to mitigate nanoparticle-NBRP interactions. As these interactions affect nanoparticle delivery, we studied the preclinical literature from 2011-2021 and analyzed nanoparticle blood circulation and organ biodistribution data. Our findings revealed that nanoparticle surface chemistry affected the in vivo behavior more than other nanoparticle design parameters. Combinatory biological-PEG surface modification improved the blood area under the curve by ~418%, with a decrease in liver accumulation of up to 47%. A greater understanding of nanoparticle-NBRP interactions and associated delivery trends will provide new nanoparticle design and biological modulation strategies for safer, more effective, and more efficient nanomedicines.

Immune Landscape and an RBM38-Associated Immune Prognostic Model with Laboratory Verification in Malignant Melanoma

Simple Summary

The primary treatment of malignant melanoma is a classical regimen of surgery combined with chemotherapy, targeted drugs, and immunotherapy. The purpose of this study was to explore the immune response mechanism of RNA binding protein RBM38 in the development of melanoma with the screening of effective immunodiagnostic models and targeted therapy. We found that RBM38, as an oncogene, promotes the proliferation, invasion, and migration of melanoma cells and is associated with immune infiltration and pathways. Our investigation presented the prognostic significance of RBM38-associated immune signature. In addition, this model may provide a potential strategy for improving the survival and immunotherapy of melanoma patients.

Abstract

Background: Current studies have revealed that RNA-binding protein RBM38 is closely related to tumor development, while its role in malignant melanoma remains unclear. Therefore, this research aimed to investigate the function of RBM38 in melanoma and the prognosis of the disease. Methods: Functional experiments (CCK-8 assay, cell colony formation, transwell cell migration/invasion experiment, wound healing assay, nude mouse tumor formation, and immunohistochemical analysis) were applied to evaluate the role of RBM38 in malignant melanoma. Immune-associated differentially expressed genes (DEGs) on RBM38 related immune pathways were comprehensively analyzed based on RNA sequencing results. Results: We found that high expression of RBM38 promoted melanoma cell proliferation, invasion, and migration, and RBM38 was associated with immune infiltration. Then, a five-gene (A2M, NAMPT, LIF, EBI3, and ERAP1) model of RBM38-associated immune DEGs was constructed and validated. Our signature showed superior prognosis capacity compared with other melanoma prognostic signatures. Moreover, the risk score of our signature was connected with the infiltration of immune cells, immune-regulatory proteins, and immunophenoscore in melanoma. Conclusions: We constructed an immune prognosis model using RBM38-related immune DEGs that may help evaluate melanoma patient prognosis and immunotherapy modalities.

Calcium activity in response to nAChR ligands in murine bone marrow granulocytes with different Gr-1 expression

Polymorphonuclear neutrophilic granulocytes (PMNs) are the largest proportion of leukocytes in adult human blood that perform numerous functions, including phagocytosis, degranulation, generation of reactive oxygen species, and NETosis. Excessive neutrophil activity associates with hyperinflammation and tissue damage during pathologies such as inflammatory bowel disease, diabetes mellitus, tuberculosis, and coronavirus disease 2019. Nicotinic acetylcholine receptors (nAChRs) can modulate immune cells, including neutrophils, functions, therefore, nAChR ligands are considered as the potent agents for therapy of inflammation. Earlier it was shown, that about 30% of PMNs from the acute inflammatory site responded to nicotine by calcium spikes. In this study, we studied the generation of calcium spikes in murine granulocytes with different maturity level (evaluated by Gr-1 expression) isolated from bone marrow in response to ligands of nAChRs in control and under chronic nicotine consumption. It was found that nearly 20%-25% cells in the granulocyte population responded to nicotine or selective antagonists of different type of nAChRs (α-cobratoxin, GIC, and Vc1.1). We demonstrated that in the control group Ca2+ -mobilizing activity was regulated through α7 and α9α10 nAChRs in immature granulocytes (Gr-1int ), whereas in mature granulocytes (Gr-1hi ) it was regulated through α7, α3β2, and α9-contained nAChRs. Sensitivity of PMNs to nicotine depended on their maturity level after chronic nicotine consumption. Gr-1int cells responded to nicotine through α7 and α9-contained nAChRs, while Gr-1hi did not respond to nicotine. Thus, calcium response to nAChR ligands in bone marrow PMNs depends on their maturity level.

Modulation of the anticancer activities of paclitaxel by Cremophor micelles

The objective of this study was to determine the effect of Cremophor (CrEL) on the antineoplastic effect induced by paclitaxel (PTX). Fluorescence spectroscopy, employing pyrene as a probe, was used to determine the critical micelle concentration (CMC) of CrEL. EL4 murine thymoma cells and MDA-MB-231 human breast cancer cells were treated with PTX in different concentrations of CrEL. G2 arrest with 8 N polyploidy was observed in PTX-treated EL4 cells but not in MDA-MB-231 cells. Cell cycle analysis via propidium iodide (PI) staining showed that the frequency of G2 arrest decreased as the CrEL concentration exceeded 0.02% (w/v), demonstrating the effect of CrEL micelle formation on the antimitotic activity of PTX. CrEL was also shown to enhance PTX-induced cell death in vitro by Annexin V/PI staining. Treatment of C57BL/6 mice with PTX in a lower concentration of CrEL resulted in higher myelosuppression, decreased both Ki-67 expression and survival rate, suggesting that CrEL micelle formation above the CMC may lower the cytotoxic activity of PTX in vivo. The data obtained in this study demonstrate CrEL micelle-mediated modulation of the cell cycle and cell death induced by PTX in vitro and the antineoplastic efficacy of PTX in vivo.

Novel CD11b+Gr-1+Sca-1+ myeloid cells drive mortality in bacterial infection

Extreme pathophysiological stressors induce expansion of otherwise infrequent leukocyte populations. Here, we found a previously unidentified CD11b⁺Gr-1⁺ myeloid cell population that expresses stem cell antigen-1 (Sca-1) induced upon experimental infection with Staphylococcus aureus. Although CD11b⁺Gr-1⁺Sca-1⁺ cells have impaired migratory capacity and superoxide anion-producing activity, they secrete increased levels of several cytokines and chemokines compared to Sca-1^- counterparts. The generation of CD11b⁺Gr-1⁺Sca-1⁺ cells is dependent on IFN-γ in vivo, and in vitro stimulation of bone marrow cells or granulocyte-macrophage progenitors with IFN-γ generated CD11b⁺Gr-1⁺Sca-1⁺ cells. Depletion of CD11b⁺Gr-1⁺Sca-1⁺ cells by administrating anti-Sca-1 antibody strongly increased survival rates in an S. aureus infection model by reducing organ damage and inflammatory cytokines. However, adoptive transfer of CD11b⁺Gr-1⁺Sca-1⁺ cells decreased survival rates by worsening the pathogenesis of S. aureus infection. Together, we found a previously unidentified pathogenic CD11b⁺Gr-1⁺Sca-1⁺ population that plays an essential role in mortality during bacterial infection.

Protein delivery by porous cationic maltodextrin-based nanoparticles into nasal mucosal cells: Comparison with cationic or anionic nanoparticles

Different types of biodegradable nanoparticles (NPs) have been studied as delivery systems for proteins into nasal mucosal cells, especially for vaccine applications. Such a nanocarrier must have the ability to be loaded with proteins and to transport this payload into mucosal cells. However, comparative data on nanoparticles' capacity for protein loading, efficiency of subsequent endocytosis and the quantity of nanocarriers used are either lacking or contradictory, making comparisons and the choice of a best candidate difficult. Here we compared 5 types of nanoparticles with different surface charge (anionic or cationic) and various inner compositions as potential vectors: the NPL (cationic maltodextrin NP with an anionic lipid core), cationic and anionic PLGA (Poly Lactic co-Glycolic Acid) NP, and cationic and anionic liposomes. We first quantified the protein association efficiency and NPL associated the largest amount of ovalbumin, used as a model protein. In vitro, the delivery of fluorescently-labeled ovalbumin into mucosal cells (airway epithelial cells, dendritic cells and macrophages) was assessed by flow cytometry and revealed that the NPL delivered protein to the greatest extent in all 3 different cell lines. Taken together, these data underlined the potential of the porous and cationic maltodextrin-based NPL as efficient protein delivery systems to mucosal cells.