Biological Effects of Nanoparticles on Macrophage Polarization in the Tumor Microenvironment

Nanomedicine for cancer patient-centered care

Cancer is a leading cause of morbidity and mortality worldwide, and an increase in incidence is estimated in the next future, due to population aging, which requires the development of highly tolerable and low-toxicity cancer treatment strategies. The use of nanotechnology to tailor treatments according to the genetic and immunophenotypic characteristics of a patient's tumor, and to allow its targeted release, can meet this need, improving the efficacy of treatment and minimizing side effects. Nanomedicine-based approach for the diagnosis and treatment of cancer is a rapidly evolving field. Several nanoformulations are currently in clinical trials, and some have been approved and marketed. However, their large-scale production and use are still hindered by an in-depth debate involving ethics, intellectual property, safety and health concerns, technical issues, and costs. Here, we survey the key approaches, with specific reference to organ-on chip technology, and cutting-edge tools, such as CRISPR/Cas9 genome editing, through which nanosystems can meet the needs for personalized diagnostics and therapy in cancer patients. An update is provided on the nanopharmaceuticals approved and marketed for cancer therapy and those currently undergoing clinical trials. Finally, we discuss the emerging avenues in the field and the challenges to be overcome for the transfer of nano-based precision oncology into clinical daily life.

Cell-mediated nanoparticle delivery systems: towards precision nanomedicine

Cell-mediated nanoparticle delivery systems (CMNDDs) utilize cells as carriers to deliver the drug-loaded nanoparticles. Unlike the traditional nanoparticle drug delivery approaches, CMNDDs take the advantages of cell characteristics, such as the homing capabilities of stem cells, inflammatory chemotaxis of neutrophils, prolonged blood circulation of red blood cells, and internalization of macrophages. Subsequently, CMNDDs can easily prolong the blood circulation, cross biological barriers, such as the blood-brain barrier and the bone marrow-blood barrier, and rapidly arrive at the diseased areas. Such advantageous properties make CMNDDs promising delivery candidates for precision targeting. In this review, we summarize the recent advances in CMNDDs fabrication and biomedical applications. Specifically, ligand-receptor interactions, non-covalent interactions, covalent interactions, and internalization are commonly applied in constructing CMNDDs in vitro. By hitchhiking cells, such as macrophages, red blood cells, monocytes, neutrophils, and platelets, nanoparticles can be internalized or attached to cells to construct CMNDDs in vivo. Then we highlight the recent application of CMNDDs in treating different diseases, such as cancer, central nervous system disorders, lung diseases, and cardiovascular diseases, with a brief discussion about challenges and future perspectives in the end.

The impact of macrophage phenotype and heterogeneity on the total internalized gold nanoparticle counts

Macrophages play a pivotal role in the internalization and processing of administered nanoparticles (NPs). Furthermore, the phagocytic capacity and immunological properties of macrophages can vary depending on their microenvironment, exhibiting a spectrum of polarization states ranging from pro-inflammatory M1 to anti-inflammatory M2. However, previous research investigating this phenotype-dependent interaction with NPs has predominantly relied on semi-quantitative techniques or conventional metrics to assess intracellular NPs. Here, we focus on the interaction of human monocyte-derived macrophage phenotypes (M1-like and M2-like) with gold NPs (AuNPs) by combining population-based metrics and single-cell analysis by focused ion beam-scanning electron microscopy (FIB-SEM). The multimodal analysis revealed phenotype-dependent response and uptake behavior differences, becoming more pronounced after 48 hours. The study also highlighted phenotype-dependent cell-to-cell heterogeneity in AuNPs uptake and variability in particle number at the single-cell level, which was particularly evident in M2-like macrophages, which increases with time, indicating enhanced heteroscedasticity. Future efforts to design NPs targeting macrophages should consider the phenotypic variations and the distribution of NPs concentrations within a population, including the influence of cell-to-cell heterogeneity. This comprehensive understanding will be critical in developing safe and effective NPs to target different macrophage phenotypes.

Understanding Macrophage Interaction with Antimony-Doped Tin Oxide Plasmonic Nanoparticles

Antimony-doped tin oxide nanoparticles (ATO NPs) have emerged as a promising tool in biomedical applications, namely robust photothermal effects upon near-infrared (NIR) light exposure, enabling controlled thermal dynamics to induce spatial cell death. This study investigated the interplay between ATO NPs and macrophages, understanding cellular uptake and cytokine release. ATO NPs demonstrated biocompatibility with no impact on macrophage viability and cytokine secretion. These findings highlight the potential of ATO NPs for inducing targeted cell death in cancer treatments, leveraging their feasibility, unique NIR properties, and safe interactions with immune cells. ATO NPs offer a transformative platform with significant potential for future biomedical applications by combining photothermal capabilities and biocompatibility.

Entry of nanoparticles into cells and tissues: status and challenges

In this article we discuss how nanoparticles (NPs) of different compositions may interact with and be internalized by cells, and the consequences of that for cellular functions. A large number of NPs are made with the intention to improve cancer treatment, the goal being to increase the fraction of injected drug delivered to the tumor and thereby improve the therapeutic effect and decrease side effects. Thus, we discuss how NPs are delivered to tumors and some challenges related to investigations of biodistribution, pharmacokinetics, and excretion. Finally, we discuss requirements for bringing NPs into clinical use and aspects when it comes to usage of complex and slowly degraded or nondegradable NPs.

Effects of chain lengths and backbone chirality on the bone-targeting ability of poly(glutamic acid)s

Anionic synthetic polypeptides are promising candidates as standalone bone-targeting drug carriers. Nevertheless, the structure-property relationship of the bone-targeting ability of polypeptides remains largely unexplored. Herein we report the optimization of the in vitro and in vivo bone-targeting ability of poly(glutamic acid)s (PGAs) by altering their chain lengths and backbone chirality. PGA 100-mers exhibited higher hydroxyapatite affinity in vitro, but their rapid macrophage clearance limited their targeting ability. Shorter PGA was therefore favored in terms of in vivo bone targeting. Meanwhile, the backbone chirality showed less significant impact on the in vitro and in vivo targeting behavior. This study highlights the modulation of structural parameters on the bone-targeting performance of anionic polypeptides, shedding light on the future design of polypeptide-based carriers.

The Potential of Photodynamic Therapy Using Solid Lipid Nanoparticles with Aluminum Phthalocyanine Chloride as a Nanocarrier for Modulating Immunogenic Cell Death in Murine Melanoma In Vitro

Photodynamic therapy (PDT) uses a photosensitizer to generate reactive oxygen species (ROS) that kill target cells. In cancer treatments, PDT can potentially induce immunogenic cell death (ICD), which is characterized by a well-controlled exposure of damage-associated molecular patterns (DAMPs) that activate dendritic cells (DCs) and consequently modulate the immune response in the tumor microenvironment. However, PDT still has limitations, such as the activity of photosensitizers in aqueous media and poor bioavailability. Therefore, a new photosensitizer system, SLN-AlPc, has been developed to improve the therapeutic efficacy of PDT. In vitro experiments showed that the light-excited nanocarrier increased ROS production in murine melanoma B16-F10 cells and modulated the profile of DCs. PDT induced cell death accompanied by the exposure of DAMPs and the formation of autophagosomes. In addition, the DCs exposed to PDT-treated B16-F10 cells exhibited morphological changes, increased expression of MHCII, CD86, CD80, and production of IL-12 and IFN-γ, suggesting immune activation towards an antitumor profile. These results indicate that the SLNs-AlPc protocol has the potential to improve PDT efficacy by inducing ICD and activating DCs.

Regenerative endodontic therapy: From laboratory bench to clinical practice

BACKGROUND

Maintaining the vitality and functionality of dental pulp is paramount for tooth integrity, longevity, and homeostasis. Aiming to treat irreversible pulpitis and necrosis, there has been a paradigm shift from conventional root canal treatment towards regenerative endodontic therapy.

AIM OF REVIEW

This extensive and multipart review presents crucial laboratory and practical issues related to pulp-dentin complex regeneration aimed towards advancing clinical translation of regenerative endodontic therapy and enhancing human life quality.

KEY SCIENTIFIC CONCEPTS OF REVIEW

In this multipart review paper, we first present a panorama of emerging potential tissue engineering strategies for pulp-dentin complex regeneration from cell transplantation and cell homing perspectives, emphasizing the critical regenerative components of stem cells, biomaterials, and conducive microenvironments. Then, this review provides details about current clinically practiced pulp regenerative/reparative approaches, including direct pulp capping and root revascularization, with a specific focus on the remaining hurdles and bright prospects in developing such therapies. Next, special attention was devoted to discussing the innovative biomimetic perspectives opened in establishing functional tissues by employing exosomes and cell aggregates, which will benefit the clinical translation of dental pulp engineering protocols. Finally, we summarize careful consideration that should be given to basic research and clinical applications of regenerative endodontics. In particular, this review article highlights significant challenges associated with residual infection and inflammation and identifies future insightful directions in creating antibacterial and immunomodulatory microenvironments so that clinicians and researchers can comprehensively understand crucial clinical aspects of regenerative endodontic procedures.

Assessing the toxicity of one-step-synthesized PEG-coated gold nanoparticles: in vitro and in vivo studies

OBJECTIVE

To evaluate the in vitro and in vivo toxicities of polyethylene glycol-coated gold nanoparticles synthesized using a one-step process.

METHODS

Gold nanoparticles were prepared via a co-precipitation method using polyethylene glycol, and the synthesis product was characterized. For the in vitro evaluation, a flow cytometry analysis with Annexin V and iodide propidium staining was used to assess cytotoxicity in MG-63 cells labeled with 10, 50, and 100µg/mL of nanoparticle concentration. For the in vivo evaluation, nanoparticles were administered intraperitoneally at a dose of 10mg/kg dose in 10-week-old mice. Toxicity was assessed 24 hours and 7 days after administration via histopathological analysis of various tissues, as well as through renal, hepatic, and hematopoietic evaluations.

RESULTS

Synthesized nanoparticles exhibited different hydrodynamic sizes depending on the medium: 51.27±1.62nm in water and 268.12±28.45nm (0 hour) in culture medium. They demonstrated a maximum absorbance at 520nm and a zeta potential of -8.419mV. Cellular viability exceeded 90%, with less than 3% early apoptosis, 6% late apoptosis, and 1% necrosis across all labeling conditions, indicating minimal cytotoxicity differences. Histopathological analysis highlighted the accumulation of nanoparticles in the mesentery; however, no lesions or visible agglomeration was observed in the remaining tissues. Renal, hepatic, and hematopoietic analyses showed no significant differences at any time point.

CONCLUSION

Polyethylene glycol-coated gold nanoparticles exhibit extremely low toxicity and high biocompatibility, showing promise for future studies.

Preclinical Efficacy of Cabazitaxel Loaded Poly(2-alkyl cyanoacrylate) Nanoparticle Variants

Background

Biodegradable poly(alkyl cyanoacrylate) (PACA) nanoparticles (NPs) are receiving increasing attention in anti-cancer nanomedicine development not only for targeted cancer chemotherapy, but also for modulation of the tumor microenvironment. We previously reported promising results with cabazitaxel (CBZ) loaded poly(2-ethylbutyl cyanoacrylate) NPs (PEBCA-CBZ NPs) in a patient derived xenograft (PDX) model of triple-negative breast cancer, and this was associated with a decrease in M2 macrophages. The present study aims at comparing two endotoxin-free PACA NP variants (PEBCA and poly(2-ethylhexyl cyanoacrylate); PEHCA), loaded with CBZ and test whether conjugation with folate would improve their effect.

Methods

Cytotoxicity assays and cellular uptake of NPs by flow cytometry were performed in different breast cancer cells. Biodistribution and efficacy studies were performed in PDX models of breast cancer. Tumor associated immune cells were analyzed by multiparametric flow cytometry.

Results

In vitro studies showed similar NP-induced cytotoxicity patterns despite difference in early NP internalization. On intravenous injection, the liver cleared the majority of NPs. Efficacy studies in the HBCx39 PDX model demonstrated an enhanced effect of drug-loaded PEBCA variants compared with free drug and PEHCA NPs. Furthermore, the folate conjugated PEBCA variant did not show any enhanced effects compared with the unconjugated counterpart which might be due to unfavorable orientation of folate on the NPs. Finally, analyses of the immune cell populations in tumors revealed that treatment with drug loaded PEBCA variants affected the myeloid cells, especially macrophages, contributing to an inflammatory, immune activated tumor microenvironment.

Conclusion

We report for the first time, comparative efficacy of PEBCA and PEHCA NP variants in triple negative breast cancer models and show that CBZ-loaded PEBCA NPs exhibit a combined effect on tumor cells and on the tumor associated myeloid compartment, which may boost the anti-tumor response.

Cross-Modal Imaging Reveals Nanoparticle Uptake Dynamics in Hematopoietic Bone Marrow during Inflammation

Nanoparticles have been employed to elucidate the innate immune cell biology and trace cells accumulating at inflammation sites. Inflammation prompts innate immune cells, the initial responders, to undergo rapid turnover and replenishment within the hematopoietic bone marrow. Yet, we currently lack a precise understanding of how inflammation affects cellular nanoparticle uptake at the level of progenitors of innate immune cells in the hematopoietic marrow. To bridge this gap, we aimed to develop imaging tools to explore the uptake dynamics of fluorescently labeled cross-linked iron oxide nanoparticles in the bone marrow niche under varying degrees of inflammation. The inflammatory models included mice that received intramuscular lipopolysaccharide injections to induce moderate inflammation and streptozotocin-induced diabetic mice with additional intramuscular lipopolysaccharide injections to intensify inflammation. In vivo magnetic resonance imaging (MRI) and fluorescence imaging revealed an elevated level of nanoparticle uptake at the bone marrow as the levels of inflammation increased. The heightened uptake of nanoparticles within the inflamed marrow was attributed to enhanced permeability and retention with increased nanoparticle intake by hematopoietic progenitor cells. Moreover, intravital microscopy showed increased colocalization of nanoparticles within slowly patrolling monocytes in these inflamed hematopoietic marrow niches. Our discoveries unveil a previously unknown role of the inflamed hematopoietic marrow in enhanced storage and rapid deployment of nanoparticles, which can specifically target innate immune cells at their production site during inflammation. These insights underscore the critical function of the hematopoietic bone marrow in distributing iron nanoparticles to innate immune cells during inflammation. Our findings offer diagnostic and prognostic value, identifying the hematopoietic bone marrow as an imaging biomarker for early detection in inflammation imaging, advancing personalized clinical care.

Magnetic-driven Interleukin-4 internalization promotes magnetic nanoparticle morphology and size-dependent macrophage polarization

Macrophages are known to depict two major phenotypes: classically activated macrophages (M1), associated with high production of pro-inflammatory cytokines, and alternatively activated macrophages (M2), which present an anti-inflammatory function. A precise control over M1-M2 polarization is a promising strategy in therapeutics to modulate both tissue regeneration and tumor progression processes. However, this is not a simple task as macrophages behave differently depending on the microenvironment. In agreement with this, non-consistent data have been reported regarding macrophages response to magnetic iron oxide nanoparticles (MNPs). To investigate the impact of both tissue microenvironment and MNPs properties on the obtained macrophage responses, single-core (SC) and multi-core (MC) citrate coated MNPs, are synthesized and, afterwards, loaded with a macrophage polarization trigger, IL-4. The developed MNPs are then tested in macrophages subjected to different stimuli. We demonstrate that macrophages treated with low concentrations of MNPs behave differently depending on the polarization stage independently of the concentration of iron. Moreover, we find out that MNPs size and morphology determines the effect of the IL-4 loaded MNPs on M1 macrophages, since IL-4 loaded SC MNPs favor the polarization of M1 macrophages towards M2 phenotype, while IL-4 loaded MC MNPs further stimulate the secretion of pro-inflammatory cytokines.

Integrating osteoimmunology and nanoparticle-based drug delivery systems for enhanced fracture healing

Fracture healing is a complex interplay of molecular and cellular mechanisms lasting from days to weeks. The inflammatory phase is the first stage of fracture healing and is critical in setting the stage for successful healing. There has been growing interest in exploring the role of the immune system and novel therapeutic strategies, such as nanoparticle drug delivery systems in enhancing fracture healing. Advancements in nanotechnology have revolutionized drug delivery systems to the extent that they can modulate immune response during fracture healing by leveraging unique physiochemical properties. Therefore, understanding the intricate interactions between nanoparticle-based drug delivery systems and the immune response, specifically macrophages, is essential for therapeutic efficacy. This review provides a comprehensive overview of the relationship between the immune system and nanoparticles during fracture healing. Specifically, we highlight the influence of nanoparticle characteristics, such as size, surface properties, and composition, on macrophage activation, polarization, and subsequent immune responses. IMPACT STATEMENT: This review provides valuable insights into the interplay between fracture healing, the immune system, and nanoparticle-based drug delivery systems. Understanding nanoparticle-macrophage interactions can advance the development of innovative therapeutic approaches to enhance fracture healing, improve patient outcomes, and pave the way for advancements in regenerative medicine.

Mercury-induced excitotoxicity in presynaptic brain nerve terminals: modulatory effects of carbonaceous airborne particulate simulants

Multipollutant approach is a breakthrough in up-to-date environmental quality and health risk estimation. Both mercury and carbonaceous air particulate are hazardous neurotoxicants. Here, the ability of carbonaceous air particulate simulants, i.e. carbon dots obtained by heating of organics, and nanodiamonds, to influence Hg2+-induced neurotoxicity was monitored using biological system, i.e. presynaptic rat cortex nerve terminals. Using HgCl2 and classical reducing/chelating agents, an adequate synaptic parameter, i.e. the extracellular level of key excitatory neurotransmitter L-[14C]glutamate, was selected for further analysis. HgCl2 starting from 5 µM caused an acute and concentration-dependent increase in the extracellular L-[14C]glutamate level in nerve terminals. Combined application of Hg2+ and carbon dots from heating of citric acid/urea showed that this simulant was able to mitigate in an acute manner excitotoxic Hg2+-induced increase in the extracellular L-[14C]glutamate level in nerve terminals by 37%. These carbon dots and Hg2+ acted as a complex in nerve terminals that was confirmed with fluorimetric data on Hg2+-induced changes in their spectroscopic features. Nanodiamonds and carbon dots from β-alanine were not able to mitigate a Hg2+-induced increase in the extracellular L-[14C]glutamate level in nerve terminals. Developed approach can be applicable for monitoring capability of different particles/compounds to have Hg2+-chelating signs in the biological systems. Therefore, among testing simulants, the only carbon dots from citric acid/urea were able to mitigate acute Hg2+-induced neurotoxicity in nerve terminals, thereby showing a variety of effects of carbonaceous airborne particulate in situ and its potential to interfere and modulate Hg2+-associated health hazard.

Manipulating macrophage polarization with nanoparticles to control metastatic behavior in heterotypic breast cancer micro-tissues via exosome signaling

This study aimed to investigate the effects of nanoparticles on macrophage polarization and their subsequent influence on post-tumorigenic behavior. Initially, seven different nanoparticles were applied to macrophages, and Zn-Ni-FeO (100 nm) and palladium nanoparticles (PdNPs, ∼25 nm) were found to induce M1-polarization in macrophages. A co-culture experiment was then conducted to examine the effects of macrophages on MCF-7 breast cancer micro-tissues. The M2-macrophages promoted tumor proliferation, while M1- and PdNPs-induced macrophages showed anti-tumor effects by suppressing cell proliferation. To reveal the mechanisms of effect, exosomes isolated from M1 (M1-Exo), M0 (M0-Exo), M2 (M2-Exo), and PdNPs-induced (PdNPs-Exo) macrophages were applied to the heterotypic tumor micro-tissues including MCF-7, human umbilical vein endothelial cells (HUVECs), and primary human dermal fibroblasts (phDFs). M2-Exo was seen to promote the migration of cancer cells and induce epithelial-mesenchymal transition (EMT), while M1-Exo suppressed these behaviors. PdNPs-Exo was effective in suppressing the aggressive nature of breast cancer cells similar to M1-Exo, moreover, the efficacy of 5-fluorouracil (5-FU) was increased in combination with PdNPs-Exo in both MCF-7 and heterotypic micro-tissues. In conclusion, PdNPs-Exo has potential anti-tumor effects, can be used as a combination therapy to enhance the efficacy of anti-cancer drugs, as well as innovative implants for breast cancer treatment.

Impact of Macrophages on the Interaction of Cetuximab-Functionalized Polyelectrolyte Capsules with EGFR-Expressing Cancer Cells

Polyelectrolyte capsules (PCs) are a promising tool for anticancer drug delivery and tumor targeting. Surface functionalization of PCs with antibodies is widely used for providing their specific interactions with cancer cells. The efficiency of PC-based targeted delivery systems can be affected by the cellular heterogeneity of the tumor, particularly by the presence of tumor-associated macrophages. We used human epidermoid carcinoma cells and macrophages derived from human leukemia monocytic cells in either monoculture or coculture to analyze the targeting capacity and internalization efficiency of PCs with a mean size of 1.03 ± 0.11 μm. The PCs were functionalized with the monoclonal antibody cetuximab targeting the human epidermal growth factor receptor (EGFR). We have shown that surface functionalization of the PCs with cetuximab ensures a specific interaction with EGFR-expressing cancer cells and promotes capsule internalization. In monoculture, the macrophages derived from human leukemia monocytic cells have been found to internalize both nonfunctionalized PCs and cetuximab-functionalized PCs (Cet-PCs) more intensely compared to epidermoid carcinoma cells. The internalization of Cet-PCs by cancer cells is mediated by lipid rafts of the cell membrane, whereas the PC internalization by macrophages is only slightly influenced by lipid rafts. Experiments with a coculture of human epidermoid carcinoma cells and macrophages derived from human leukemia monocytic cells have shown that Cet-PCs preferentially interact with cancer cells, which are subsequently attacked by macrophages. These data can be used to further improve the strategy of PC functionalization for targeted delivery, with the cellular heterogeneity of the tumor microenvironment taken into consideration.

Upregulation of exosome secretion from tumor-associated macrophages plays a key role in the suppression of anti-tumor immunity

Macrophages play a pivotal role in tumor immunity. We report that reprogramming of macrophages to tumor-associated macrophages (TAMs) promotes the secretion of exosomes. Mechanistically, increased exosome secretion is driven by MADD, which is phosphorylated by Akt upon TAM induction and activates Rab27a. TAM exosomes carry high levels of programmed death-ligand 1 (PD-L1) and potently suppress the proliferation and function of CD8+ T cells. Analysis of patient melanoma tissues indicates that TAM exosomes contribute significantly to CD8+ T cell suppression. Single-cell RNA sequencing analysis showed that exosome-related genes are highly expressed in macrophages in melanoma; TAM-specific RAB27A expression inversely correlates with CD8+ T cell infiltration. In a murine melanoma model, lipid nanoparticle delivery of small interfering RNAs (siRNAs) targeting macrophage RAB27A led to better T cell activation and sensitized tumors to anti-programmed cell death protein 1 (PD-1) treatment. Our study demonstrates tumors use TAM exosomes to combat CD8 T cells and suggests targeting TAM exosomes as a potential strategy to improve immunotherapies.

Functional impact of oxygen-saturated zeolite nanoparticles on macrophages in the context of glioblastoma: an in vitro and in vivo study

In the context of glioblastoma (GBM), hypoxia and inflammation are two main players of the tumor microenvironment. Hypoxia stimulates various features involves in tumor growth and also maintains a specific environment that favors protumor macrophages. Therefore, targeting hypoxia could potentially restore an anti-tumor M1 phenotype in macrophages. Besides, iron demonstrated its capacity to stimulate the polarization of macrophages towards an M1-like phenotype. In this paper we took advantages of microporous nanoparticles to co-deliver both oxygen and iron to bone marrow derived macrophages (BMDM) enabling the investigation of changes in polarization status and proteomic profiles. The nanoparticles were used in two in vivo models of glioblastoma, specifically, in both immunodeficient and immunocompetent settings. Our in vitro findings revealed that iron doped nanoparticles, saturated with oxygen were deemed safe for macrophages but did not demonstrate the capacity to change the M1 or M2 phenotypes. However, these nanoparticles induced some changes in proteomics pathways. The present study reports on in vivo experimentation that revealed the effects of nanoparticles on the hypoxic fraction, tumor volume, and macrophage phenotype in a GBM model. The findings indicated that the presence of nanoparticles led to a reduction in the hypoxic fraction in one of the GBM models, while no significant changes were observed in the tumor volume or macrophage phenotype. The present data showed that nanoparticles possess the capability of delivering both oxygen and iron to macrophages; though, they do not possess the ability to effectively repolarize M2 macrophages. Such strategies could be used in conjunction with other potent molecules to avoid M1 macrophages to inevitably differentiate to M2 macrophages.

Unraveling the potential of 3D bioprinted immunomodulatory materials for regulating macrophage polarization: State-of-the-art in bone and associated tissue regeneration

Macrophage-assisted immunomodulation is an alternative strategy in tissue engineering, wherein the interplay between pro-inflammatory and anti-inflammatory macrophage cells and body cells determines the fate of healing or inflammation. Although several reports have demonstrated that tissue regeneration depends on spatial and temporal regulation of the biophysical or biochemical microenvironment of the biomaterial, the underlying molecular mechanism behind immunomodulation is still under consideration for developing immunomodulatory scaffolds. Currently, most fabricated immunomodulatory platforms reported in the literature show regenerative capabilities of a particular tissue, for example, endogenous tissue (e.g., bone, muscle, heart, kidney, and lungs) or exogenous tissue (e.g., skin and eye). In this review, we briefly introduced the necessity of the 3D immunomodulatory scaffolds and nanomaterials, focusing on material properties and their interaction with macrophages for general readers. This review also provides a comprehensive summary of macrophage origin and taxonomy, their diverse functions, and various signal transduction pathways during biomaterial-macrophage interaction, which is particularly helpful for material scientists and clinicians for developing next-generation immunomodulatory scaffolds. From a clinical standpoint, we briefly discussed the role of 3D biomaterial scaffolds and/or nanomaterial composites for macrophage-assisted tissue engineering with a special focus on bone and associated tissues. Finally, a summary with expert opinion is presented to address the challenges and future necessity of 3D bioprinted immunomodulatory materials for tissue engineering.

Nanoparticles systemically biodistribute to regenerating skeletal muscle in DMD

Skeletal muscle disease severity can often progress asymmetrically across muscle groups and heterogeneously within tissues. An example is Duchenne Muscular Dystrophy (DMD) in which lack of dystrophin results in devastating skeletal muscle wasting in some muscles whereas others are spared or undergo hypertrophy. An efficient, non-invasive approach to identify sites of asymmetry and degenerative lesions could enable better patient monitoring and therapeutic targeting of disease. In this study, we utilized a versatile intravenously injectable mesoporous silica nanoparticle (MSNP) based nanocarrier system to explore mechanisms of biodistribution in skeletal muscle of mdx mouse models of DMD including wildtype, dystrophic, and severely dystrophic mice. Moreover, MSNPs could be imaged in live mice and whole muscle tissues enabling investigation of how biodistribution is altered by different types of muscle pathology such as inflammation or fibrosis. We found MSNPs were tenfold more likely to aggregate within select mdx muscles relative to wild type, such as gastrocnemius and quadriceps. This was accompanied by decreased biodistribution in off-target organs. We found the greatest factor affecting preferential delivery was the regenerative state of the dystrophic skeletal muscle with the highest MSNP abundance coinciding with the regions showing the highest level of embryonic myosin staining and intramuscular macrophage uptake. To demonstrate, muscle regeneration regulated MSNP distribution, we experimentally induced regeneration using barium chloride which resulted in a threefold increase of intravenously injected MSNPs to sites of regeneration 7 days after injury. These discoveries provide the first evidence that nanoparticles have selective biodistribution to skeletal muscle in DMD to areas of active regeneration and that nanoparticles could enable diagnostic and selective drug delivery in DMD skeletal muscle.

Characterization of a novel galectin in Sarcoptes scabiei and its role in regulating macrophage functions

Sarcoptes scabiei (S. scabiei) endangers human and other mammalian health. There has been limited research into S. scabiei pathogenic mechanisms and the immunological interaction between S. scabiei and hosts. Galectins have critical roles in biological processes such as cell adhesion, signal transduction, and immune response mediation. Galectins of S. scabiei (SsGalectins) were cloned, expressed, and identified, and their transcriptional levels in S. scabiei were measured at various developmental stages. Fluorescent tissue localization was performed on SsGalectins of S. scabiei and scabies skin. A mouse AD model was constructed to evaluate the effect of rSsGalectins on skin pathogenic changes. Quantitative polymerase chain reaction and enzyme-linked immunoassay were used to identify macrophage polarization-related components and investigate the immunoregulatory effect of rSsGalectins on mouse macrophages. The results demonstrated that the S. scabiei infection causes macrophage infiltration in the scabies skin. The rSsGalectins displayed strong reactogenicity, and distinct genes of the SsGalectins were differently expressed in different developmental stages of S. scabiei. Fluorescence tissue localization revealed that the SsGalectins were mainly in the mouthparts, intestines, and body surface. Additionally, S. scabiei could secrete SsGalectins into the infected skin, proving that SsGalectins were excretion and secretion proteins of S. scabiei. In the mouse atopic dermatitis model, cutaneous macrophage infiltration and inflammation increase after rSsGalectins injection. Simultaneously, when rSsGalectins acted on bone marrow-derived macrophages, M1 macrophage-related polarization factors IL-1β, IL-6, and inducible nitric oxide synthase all increased, demonstrating that rSsGalectins can induce M1 polarization and produce pro-inflammatory cytokines. In conclusion, the SsGalectins are involved in the pathogenic process of S. scabiei by regulating the polarization of host macrophages to the M1 type when S. scabiei invade the host and promoting the incidence and development of the host's inflammatory response. This study offers fresh light on the pathogenic process of scabies mites, investigates the immunological interaction mechanism between S. scabiei and the host, and offers new insights into S. scabiei prevention and therapy.

A new approach to overcoming resistance to immunotherapy: nanotechnology

Immunotherapy for immune response has ushered in a new era of cancer treatment. In recent years, new immunotherapeutic agents have been introduced into clinical trials and even approved for marketing. However, the widespread use of immunotherapeutic agents faces an unavoidable challenge: immunotherapy does not work at all for some patients, or has good efficacy in the initial phase, but immunotherapy resistance develops within a short period of time, and immunotherapy can also cause serious adverse effects such as autoimmune inflammation and non-specific inflammation. How to enable patients to overcome drug resistance, reduce the toxic side effects of drugs, enhance patient compliance and improve patient survival has become a problem that clinicians have to face. The advent of nanotechnology provides an encouraging platform for immunotherapy. It can not only improve the bioavailability and stability of drugs and reduce toxic side effects, but also reduce resistance to immunotherapy. Here, we discuss these research advances and discuss potential challenges and future directions.

Macrophages as Promising Carriers for Nanoparticle Delivery in Anticancer Therapy

Macrophages play a critical role in the immune response due to their ability to recognize and remove pathogens, as well as present antigens, which are involved in inflammation, but they are also one of the most abundant immune cell populations present in the tumor microenvironment. In recent years, macrophages have become promising cellular carriers for drug and nanoparticle delivery to the tumor microenvironment, mainly due to their natural properties such as biocompatibility, degradability, lack of immunogenicity, long half-life in circulation, crossing biological barriers, and the possibility of migration and accumulation at a site of inflammation such as a tumor. For the effectiveness of this therapeutic strategy, known as "Trojan horse", it is important that the nanoparticles engulfed by macrophages do not affect their proper functioning. In our review, we discussed how the size, shape, chemical and mechanical properties of nanoparticles influence their internalization by macrophages. In addition, we described the promising research utilizing macrophages, their cell membranes and macrophage-derived exosomes as drug carriers in anticancer therapy. As a prospect of the wider use of this therapeutic strategy, we postulate its future application in boron delivery to the tumor environment in boron neutron capture therapy.

Macrophage Reprogramming via the Modulation of Unfolded Protein Response with siRNA-Loaded Magnetic Nanoparticles in a TAM-like Experimental Model

New therapeutic strategies are required in cancer therapy. Considering the prominent role of tumor-associated macrophages (TAMs) in the development and progression of cancer, the re-education of TAMs in the tumor microenvironment (TME) could represent a potential approach for cancer immunotherapy. TAMs display an irregular unfolded protein response (UPR) in their endoplasmic reticulum (ER) to endure environmental stress and ensure anti-cancer immunity. Therefore, nanotechnology could be an attractive tool to modulate the UPR in TAMs, providing an alternative strategy for TAM-targeted repolarization therapy. Herein, we developed and tested polydopamine-coupled magnetite nanoparticles (PDA-MNPs) functionalized with small interfering RNAs (siRNA) to downregulate the protein kinase R (PKR)-like ER kinase (PERK) expression in TAM-like macrophages derived from murine peritoneal exudate (PEMs). After the evaluation of the cytocompatibility, the cellular uptake, and the gene silencing efficiency of PDA-MNPs/siPERK in PEMs, we analyzed their ability to re-polarize in vitro these macrophages from M2 to the M1 inflammatory anti-tumor phenotype. Our results indicate that PDA-MNPs, with their magnetic and immunomodulator features, are cytocompatible and able to re-educate TAMs toward the M1 phenotype by PERK inhibition, a UPR effector contributing to TAM metabolic adaptation. These findings can provide a novel strategy for the development of new tumor immunotherapies in vivo.

Leveraging Macrophage-Mediated Cancer Immunotherapy via a Cascading Effect Induced by a Molecularly Imprinted Nanocoordinator

Reprogramming tumor-associated macrophages (TAMs) has emerged as a promising strategy in cancer immunotherapy. Targeted therapeutics integrating multiple functions to fully leverage the antitumor immune functions of macrophages without affecting systemic or tissue-resident macrophages are crucial for TAM reprogramming. Herein, by integrating molecular imprinting and nanotechnology, we rationally designed and engineered an unprecedented nanocoordinator for targeted remolding of TAMs to fully leverage the antitumor efficacy of macrophages by inducing a cascade effect. The nanocoordinator features a magnetic iron oxide nanoinner core and sialic acid-imprinted shell. Intravenously administered into systemic circulation, the nanocoordinator can rapidly accumulate at the tumor site in response to an external magnet. Then, by specifically binding to sialic acid overexpressed on tumor cells, the nanocoordinator anchors at the tumor site with prolonged retention time. Via binding with the nanocoordinator, tumor cells are tagged with a foreign substance, which promotes the intrinsic phagocytosis of macrophages. Subsequently, the nanocoordinator taken up by macrophages effectively promotes the polarization of macrophages toward the M1 phenotype, thus activating the immunotherapeutic efficacy of macrophages. Synergized by the cascade effect, this nanocoordinator effectively harnesses TAMs for macrophage-mediated immunotherapy. This study offers new TAM-targeted therapeutics that allows us to fully leverage the antitumor immune functions of macrophages without affecting the normal tissue.

Next-generation biomaterials for dental pulp tissue immunomodulation

OBJECTIVES

The current standard for treating irreversibly damaged dental pulp is root canal therapy, which involves complete removal and debridement of the pulp space and filling with an inert biomaterial. A regenerative approach to treating diseased dental pulp may allow for complete healing of the native tooth structure and enhance the long-term outcome of once-necrotic teeth. The aim of this paper is, therefore, to highlight the current state of dental pulp tissue engineering and immunomodulatory biomaterials properties, identifying exciting opportunities for their synergy in developing next-generation biomaterials-driven technologies.

METHODS

An overview of the inflammatory process focusing on immune responses of the dental pulp, followed by periapical and periodontal tissue inflammation are elaborated. Then, the most recent advances in treating infection-induced inflammatory oral diseases, focusing on biocompatible materials with immunomodulatory properties are discussed. Of note, we highlight some of the most used modifications in biomaterials' surface, or content/drug incorporation focused on immunomodulation based on an extensive literature search over the last decade.

RESULTS

We provide the readers with a critical summary of recent advances in immunomodulation related to pulpal, periapical, and periodontal diseases while bringing light to tissue engineering strategies focusing on healing and regenerating multiple tissue types.

SIGNIFICANCE

Significant advances have been made in developing biomaterials that take advantage of the host's immune system to guide a specific regenerative outcome. Biomaterials that efficiently and predictably modulate cells in the dental pulp complex hold significant clinical promise for improving standards of care compared to endodontic root canal therapy.

Modulation of macrophage polarization by iron-based nanoparticles

Macrophage polarization is an essential process involved in immune regulation. In response to different microenvironmental stimulation, macrophages polarize into cells with different phenotypes and functions, most typically M1 (pro-inflammatory) and M2 (anti-inflammatory) macrophages. Iron-based nanoparticles have been widely explored and reported to regulate macrophage polarization for various biomedical applications. However, the influence factors and modulation mechanisms behind are complicated and not clear. In this review, we systemically summarized different iron-based nanoparticles that regulate macrophage polarization and function and discussed the influence factors and mechanisms underlying the modulation process. This review aims to deepen the understanding of the modulation of macrophage polarization by iron-based nanoparticles and expects to provide evidence and guidance for subsequent design and application of iron-based nanoparticles with specific macrophage modulation functions.

Impact of Nanoparticle Physicochemical Properties on Protein Corona and Macrophage Polarization

Macrophages, the major component of the mononuclear phagocyte system, uptake and clear systemically administered nanoparticles (NPs). Therefore, leveraging macrophages as a druggable target may be advantageous to enhance NP-mediated drug delivery. Despite many studies focused on NP-cell interactions, NP-mediated macrophage polarization mechanisms are still poorly understood. This work aimed to explore the effect of NP physicochemical parameters (size and charge) on macrophage polarization. Upon exposure to biological fluids, proteins rapidly adsorb to NPs and form protein coronas. To this end, we hypothesized that NP protein coronas govern NP-macrophage interactions, uptake, and subsequent macrophage polarization. To test this hypothesis, model polystyrene NPs with various charges and sizes, as well as NPs relevant to drug delivery, were utilized. Data suggest that cationic NPs potentiate both M1 and M2 macrophage markers, while anionic NPs promote M1-to-M2 polarization. Additionally, anionic polystyrene nanoparticles (APNs) of 50 nm exhibit the greatest influence on M2 polarization. Proteomics was pursued to further understand the effect of NPs physicochemical parameters on protein corona, which revealed unique protein patterns based on NP charge and size. Several proteins impacting M1 and M2 macrophage polarization were identified within cationic polystyrene nanoparticles (CPNs) corona, while APNs corona included fewer M1 but more M2-promoting proteins. Nevertheless, size impacts protein corona abundance but not identities. Altogether, protein corona identities varied based on NP surface charge and correlated to dramatic differences in macrophage polarization. In contrast, NP size differentially impacts macrophage polarization, which is dominated by NP uptake level rather than protein corona. In this work, specific corona proteins were identified as a function of NP physicochemical properties. These proteins are correlated to specific macrophage polarization programs and may provide design principles for developing macrophage-mediated NP drug delivery systems.

Cellulose nanocrystals vs. cellulose nanospheres: A comparative study of cytotoxicity and macrophage polarization potential

Nanocellulose application has been increasing owing to its appealing physicochemical properties. Monitoring of the crystallinity, surface topography, and reactivity of this high-aspect-ratio nanomaterial is crucial for efficient tissue engineering. Controlling macrophage polarization phenotype remains a challenge in regenerative medicine and tissue engineering. Herein, we monitored the effects of shape-regulated (rod and spherical) nanocellulose on the macrophage modulatory potential of RAW 246.7 cells in vitro. Spherical nanocellulose (s-NC) exhibited higher thermal stability and biocompatibility than rod nanocellulose. Macrophage polarization was profoundly affected by nanocellulose topography and incubation period. M2 polarization was observed in vitro after 1 day of treatment with s-NC, followed by M1 polarization after treatment for longer periods. Transcriptome analysis similarly revealed that M1 polarization was dominant after 1 day h of incubation with both nanocellulose types. These findings demonstrate that macrophage polarization can be controlled by selecting suitable nanocellulose shape and incubation time for desired applications.

Thiolated Mesoporous Silica Nanoparticles as an Immunoadjuvant to Enhance Efficacy of Intravesical Chemotherapy for Bladder Cancer

The characteristics of global prevalence and high recurrence of bladder cancer has led numerous efforts to develop new treatments. The spontaneous voiding and degradation of the chemodrug hamper the efficacy and effectiveness of intravesical chemotherapy following tumor resection. Herein, the externally thiolated hollow mesoporous silica nanoparticles (MSN-SH(E)) is fabricated to serve as a platform for improved bladder intravesical therapy. Enhanced mucoadhesive effect of the thiolated nanovector is confirmed with porcine bladder. The permeation-enhancing effect is also verified, and a fragmented distribution pattern of a tight junction protein, claudin-4, indicates the opening of tight junction. Moreover, MSN-SH(E)-associated reprogramming of M2 macrophages to M1-like phenotype is observed in vitro. The antitumor activity of the mitomycin C (MMC)-loaded nanovector (MMC@MSN-SH(E)) is more effective than that of MMC alone in both in vitro and in vivo. In addition, IHC staining is used to analyze IFN-γ, TGF-β1, and TNF-α. These observations substantiated the significance of MMC@MSN-SH(E) in promoting anticancer activity, holding the great potential for being used in intravesical therapy for non-muscle invasive bladder cancer (NMIBC) due to its mucoadhesivity, enhanced permeation, immunomodulation, and prolonged and very efficient drug exposure.

Adoptive cellular immunotherapy for solid neoplasms beyond CAR-T

In recent decades, immune checkpoint blockade and chimeric antigen receptor T cell (CAR-T) therapy are two milestone achievements in clinical immunotherapy. However, both show limited efficacies in most solid neoplasms, which necessitates the exploration of new immunotherapeutic modalities. The failure of CAR-T and immune checkpoint blockade in several solid neoplasms is attributed to multiple factors, including low antigenicity of tumor cells, low infiltration of effector T cells, and diverse mechanisms of immunosuppression in the tumor microenvironment. New adoptive cell therapies have been attempted for solid neoplasms, including TCR-T, CAR-natural killer cells (CAR-NK), and CAR-macrophages (CAR-M). Compared to CAR-T, these new adoptive cell therapies have certain advantages in treating solid neoplasms. In this review, we summarized the 40-year evolution of adoptive cell therapies, then focused on the advances of TCR-T, CAR-NK, and CAR-M in solid neoplasms and discussed their potential clinical applications.

Response of the Endogenous Antioxidant Defense System Induced in RAW 264.7 Macrophages upon Exposure to Dextran-Coated Iron Oxide Nanoparticles

Presently, iron oxide nanoparticles are the only ones approved for clinical use as contrast agents in magnetic resonance imaging (MRI). Even though there is a high demand for these types of nanoparticles both for clinical use as well as for research, there are difficulties in obtaining stable nanoparticles with reproducible properties. In this context, in this study, we report the obtaining by an adapted coprecipitation method of dextran-coated maghemite nanoparticles (ɤ-Fe2O3 NPs). The morphology and structure of the dextran-coated maghemite nanoparticles (ɤ-Fe2O3 NPs) were determined using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The TEM and SEM micrographs highlighted the obtaining of particles of nanometric size and spherical shape morphology. Furthermore, the high-resolution transmission electron microscopy (HRTEM), as well as selected area diffraction (SAED), revealed that the obtained samples presented the structure of cubic maghemite. In this study, we also explored the effects of the co-precipitation synthesized dextran-coated maghemite nanoparticles (ɤ-Fe2O3 NPs) on the redox status of macrophages. For cytotoxicity evaluation of these NPs, murine macrophages (RAW 264.7 cell line) were exposed to different concentrations of dextran-coated maghemite nanoparticles (ɤ-Fe2O3 NPs) corresponding to 0-500 μg Fe3+/mL and incubated for 24, 48, and 72 h. Intracellular iron uptake, changes in the oxidative stress parameters (reactive oxygen species production and malondialdehyde level), and the activity of antioxidant enzymes, as well as GSH concentration in cells, were evaluated after incubation with a lower (50 μg Fe3+/mL) and higher (500 μg Fe3+/mL) dose of NPs. The results indicated a significant decrease in RAW 264.7 cell viability after 72 h in the presence of NPs at concentrations above 25 μg Fe3+/mL. An important accumulation of NPs, dependent on dose and exposure time, was detected in macrophages, but it induced only a limited raise in the oxidative status. We showed here that the antioxidant capacity of RAW 264.7 macrophages was efficient in counteracting dextran-coated maghemite nanoparticles (ɤ-Fe2O3 NPs) toxicity even at higher doses.

Superparamagnetic Iron Oxide Nanoparticles (SPION): From Fundamentals to State-of-the-Art Innovative Applications for Cancer Therapy

Despite significant advances in cancer therapy over the years, its complex pathological process still represents a major health challenge when seeking effective treatment and improved healthcare. With the advent of nanotechnologies, nanomedicine-based cancer therapy has been widely explored as a promising technology able to handle the requirements of the clinical sector. Superparamagnetic iron oxide nanoparticles (SPION) have been at the forefront of nanotechnology development since the mid-1990s, thanks to their former role as contrast agents for magnetic resonance imaging. Though their use as MRI probes has been discontinued due to an unfavorable cost/benefit ratio, several innovative applications as therapeutic tools have prompted a renewal of interest. The unique characteristics of SPION, i.e., their magnetic properties enabling specific response when submitted to high frequency (magnetic hyperthermia) or low frequency (magneto-mechanical therapy) alternating magnetic field, and their ability to generate reactive oxygen species (either intrinsically or when activated using various stimuli), make them particularly adapted for cancer therapy. This review provides a comprehensive description of the fundamental aspects of SPION formulation and highlights various recent approaches regarding in vivo applications in the field of cancer therapy.

Fibrotic immune microenvironment remodeling mediates superior anti-tumor efficacy of a nano-PD-L1 trap in hepatocellular carcinoma

The local microenvironment where tumors develop can shape cancer progression and therapeutic outcome. Emerging evidence demonstrate that the efficacy of immune-checkpoint blockade (ICB) is undermined by fibrotic tumor microenvironment (TME). The majority of hepatocellular carcinoma (HCC) develops in liver fibrosis, in which the stromal and immune components may form a barricade against immunotherapy. Here, we report that nanodelivery of a programmed death-ligand 1 (PD-L1) trap gene exerts superior efficacy in treating fibrosis-associated HCC when compared with the conventional monoclonal antibody (mAb). In two fibrosis-associated HCC models induced by carbon tetrachloride and a high-fat, high-carbohydrate diet, the PD-L1 trap induced significantly larger tumor regression than mAb with no evidence of toxicity. Mechanistic studies revealed that PD-L1 trap, but not mAb, consistently reduced the M2 macrophage proportion in the fibrotic liver microenvironment and promoted cytotoxic interferon gamma (IFNγ)+tumor necrosis factor α (TNF-α)+CD8+T cell infiltration to the tumor. Moreover, PD-L1 trap treatment was associated with decreased tumor-infiltrating polymorphonuclear myeloid-derived suppressor cell (PMN-MDSC) accumulation, resulting in an inflamed TME with a high cytotoxic CD8+T cell/PMN-MDSC ratio conductive to anti-tumor immune response. Single-cell RNA sequencing analysis of two clinical cohorts demonstrated preferential PD-L1 expression in M2 macrophages in the fibrotic liver, thus supporting the translational potential of nano-PD-L1 trap for fibrotic HCC treatment.

PSMA1-mediated ultrasmall gold nanoparticles facilitate tumor targeting and MR/CT/NIRF multimodal detection of early-stage prostate cancer

Prostate-specific membrane antigen (PSMA) is a prominent biomarker for prostate cancer (PCa) diagnosis. Safe contrast agents able to render the expression and distribution of PSMA would facilitate early accurate screening and prognostic prediction of PCa. However, current Gd-containing nanoparticles are often limited by nonspecific redistribution in mononuclear phagocyte system (MPS) and inadequate perfusion to target sites. Besides, intrinsic defects of magnetic resonance (MR) equipment also hamper their use for precisely depicting PSMA details. Herein, we devised a novel noninvasive MR/CT/NIRF multimodal contrast agent (AGGP) coordinated to a high-affinity PSMA ligand (PSMA1) to specifically detect and quantify PSMA expression in PCa lesions, which exhibited formidable tripe-modal signal augments, preferential PSMA targeting, effective MPS escaping and profitable renal-clearable behavior in living mice. Biocompatibility and histopathological studies substantiated high security of AGGP in vivo, opening the door to future opportunities for improving early-stage PCa detection and clinical implementation of more effective multifunctional nanotherapeutics.

A study of macrophage mechanical properties and functional modulation based on the Young's modulus of PLGA-PEG fibers

The immune response of macrophages plays an important role in defending against viral infection, tumor deterioration and repairing of contused tissue. Macrophage functional differentiation induced by nanodrugs is the leading edge of current research, but nanodrugs have toxic side effects, and the influence of their physical properties on macrophages is not clear. Here we create an alternative way to modulate macrophage function through PLGA-PEG fibers' Young's modulus. Previously, we revealed that by controlling the Young's modulus of the fibers from kPa to MPa, all the fibers entered murine macrophage cells (RWA 264.7) in a similar manner, and based on that, we found that macrophages' mechanical properties were affected by the fibers' Young's modulus, that is, hard fibers with a Young's modulus of ∼1 MPa increased the cell average Young's modulus, but did not affect the cell shape, while soft fibers with a Young's modulus of ∼100 kPa decreased the cell average Young's modulus and modulated the cell shape to a more spherical one. On the other hand, only the soft fibers induced proinflammatory cytokine secretion, indicating an M1 macrophage functional modulation by low Young's modulus fibers. This study explored the mechanical properties of the interactions between PLGA-PEG fibers and cells, in particular, when guiding the direction of the modulation of macrophage function, which is of great significance for the applications of material biology in the biomedical field.

Recent progress in molecular mechanisms of postoperative recurrence and metastasis of hepatocellular carcinoma

Hepatectomy is currently considered the most effective option for treating patients with early and intermediate hepatocellular carcinoma (HCC). Unfortunately, the postoperative prognosis of patients with HCC remains unsatisfactory, predominantly because of high postoperative metastasis and recurrence rates. Therefore, research on the molecular mechanisms of postoperative HCC metastasis and recurrence will help develop effective intervention measures to prevent or delay HCC metastasis and recurrence and to improve the long-term survival of HCC patients. Herein, we review the latest research progress on the molecular mechanisms underlying postoperative HCC metastasis and recurrence to lay a foundation for improving the understanding of HCC metastasis and recurrence and for developing more precise prevention and intervention strategies.

Smart and Multi-Functional Magnetic Nanoparticles for Cancer Treatment Applications: Clinical Challenges and Future Prospects

Iron oxide nanoparticle (IONPs) have become a subject of interest in various biomedical fields due to their magnetism and biocompatibility. They can be utilized as heat mediators in magnetic hyperthermia (MHT) or as contrast media in magnetic resonance imaging (MRI), and ultrasound (US). In addition, their high drug-loading capacity enabled them to be therapeutic agent transporters for malignancy treatment. Hence, smartening them allows for an intelligent controlled drug release (CDR) and targeted drug delivery (TDD). Smart magnetic nanoparticles (SMNPs) can overcome the impediments faced by classical chemo-treatment strategies, since they can be navigated and release drug via external or internal stimuli. Recently, they have been synchronized with other modalities, e.g., MRI, MHT, US, and for dual/multimodal theranostic applications in a single platform. Herein, we provide an overview of the attributes of MNPs for cancer theranostic application, fabrication procedures, surface coatings, targeting approaches, and recent advancement of SMNPs. Even though MNPs feature numerous privileges over chemotherapy agents, obstacles remain in clinical usage. This review in particular covers the clinical predicaments faced by SMNPs and future research scopes in the field of SMNPs for cancer theranostics.

Lighting up Micro-/Nanorobots with Fluorescence

Micro-/nanorobots (MNRs) can be autonomously propelled on demand in complex biological environments and thus may bring revolutionary changes to biomedicines. Fluorescence has been widely used in real-time imaging, chemo-/biosensing, and photo-(chemo-) therapy. The integration of MNRs with fluorescence generates fluorescent MNRs with unique advantages of optical trackability, on-the-fly environmental sensitivity, and targeting chemo-/photon-induced cytotoxicity. This review provides an up-to-date overview of fluorescent MNRs. After the highlighted elucidation about MNRs of various propulsion mechanisms and the introductory information on fluorescence with emphasis on the fluorescent mechanisms and materials, we systematically illustrate the design and preparation strategies to integrate MNRs with fluorescent substances and their biomedical applications in imaging-guided drug delivery, intelligent on-the-fly sensing and photo-(chemo-) therapy. In the end, we summarize the main challenges and provide an outlook on the future directions of fluorescent MNRs. This work is expected to attract and inspire researchers from different communities to advance the creation and practical application of fluorescent MNRs on a broad horizon.

Iron oxide nanoparticle targeting mechanism and its application in tumor magnetic resonance imaging and therapy

Iron oxide nanoparticles (IONPs) can be applied to targeted drug delivery, targeted diagnosis and treatment of tumors due to their easy preparation, good biocompatibility, low biotoxicity, high imaging quality, high magnetothermal sensitivity and stable targeting after certain surface modifications. However, the complexity of the mechanism of action and their properties has led to there being few clinical applications of IONPs. This review first describes the targeting mechanisms of IONPs and their toxicity issues, then discusses the applications of IONP targeting studies in tumor MRI. Finally, the applications of IONP targeting in tumor therapy are listed. The authors show the advantages of targeting IONPs and hope that the review will increase the possibility of converting IONPs from biomedical applications to clinical applications.

Noncoding RNA-mediated macrophage and cancer cell crosstalk in hepatocellular carcinoma

The tumor microenvironment (TME) is a well-recognized system that plays an essential role in tumor initiation, development, and progression. Intense intercellular communication between tumor cells and other cells (especially macrophages) occurs in the TME and is mediated by cell-to-cell contact and/or soluble messengers. Emerging evidence indicates that noncoding RNAs (ncRNAs) are critical regulators of the relationship between cells within the TME. In this review, we provide an update on the regulation of ncRNAs (primarily micro RNAs [miRNAs], long ncRNAs [lncRNAs], and circular RNAs [circRNAs]) in the crosstalk between macrophages and tumor cells in hepatocellular carcinoma (HCC). These ncRNAs are derived from macrophages or tumor cells and act as oncogenes or tumor suppressors, contributing to tumor progression not only by regulating the physiological and pathological processes of tumor cells but also by controlling macrophage infiltration, activation, polarization, and function. Herein, we also explore the options available for clinical therapeutic strategies targeting crosstalk-related ncRNAs to treat HCC. A better understanding of the relationship between macrophages and tumor cells mediated by ncRNAs will uncover new diagnostic biomarkers and pharmacological targets in cancer.

Targeting tumor-associated macrophages for cancer immunotherapy

Tumor-associated macrophages (TAMs) are one of the most abundant immune components in the tumor microenvironment and play a plethora of roles in regulating tumorigenesis. Therefore, the therapeutic targeting of TAMs has emerged as a new paradigm for immunotherapy of cancer. Herein, the review summarizes the origin, polarization, and function of TAMs in the progression of malignant diseases. The understanding of such knowledge leads to several distinct therapeutic strategies to manipulate TAMs to battle cancer, which include those to reduce TAM abundance, such as depleting TAMs or inhibiting their recruitment and differentiation, and those to harness or boost the anti-tumor activities of TAMs such as blocking phagocytosis checkpoints, inducing antibody-dependent cellular phagocytosis, and reprogramming TAM polarization. In addition, modulation of TAMs may reshape the tumor microenvironment and therefore synergize with other cancer therapeutics. Therefore, the rational combination of TAM-targeting therapeutics with conventional therapies including radiotherapy, chemotherapy, and other immunotherapies is also reviewed. Overall, targeting TAMs presents itself as a promising strategy to add to the growing repertoire of treatment approaches in the fight against cancer, and it is hopeful that these approaches currently being pioneered will serve to vastly improve patient outcomes and quality of life.

Polyaniline-Based Glyco-Condensation on Au Nanoparticles Enhances Immunotherapy in Lung Cancer

Lung cancer is considered among the deadliest cancers with a poor prognosis. Au@PG nanoparticles (NPs) are gold (Au)-based NPs featuring a polyaniline-based glyco structure (PG) generated from the polymerization of ortho-nitrophenyl-β-d-galactopyranoside (ONPG) with promising M1 macrophage polarization activity, resulting in tumor remodeling and from a cold to a hot microenvironment, which promotes the cytotoxic T cell response and tumor inhibition. The combination of Au@PG NPs and anti-programmed cell death protein 1 (PD-1) therapy improved tumor inhibition and immunosuppression, accompanied by the secretion of immunogenic cytokines. A one-pot synthetic method was developed to achieve glyco-condensation during the formation of Au@PG NPs, which induced macrophage polarization more efficiently than Au@glucose, Au@mannose, and Au@galactose NPs. The switch from M2 to M1 macrophages was dependent on NP size, with smaller Au@PG NPs performing better than larger ones, with effectiveness ranked as follows: 32.2 nm ≈ 29.8 nm < 26.4 nm < 18.3 nm. Cellular uptake by endocytosis induced size-dependent endoplasmic reticulum (ER) stress, which resulted in the activation of spleen tyrosine kinase (SYK), leading to immune modulations and macrophage polarization. Our results suggested the promising potential of Au@PG NPs in lung cancer immunotherapy.

Nanotechnology Tools Enabling Biological Discovery

Over the years, the engineering aspect of nanotechnology has been significantly exploited. Medical intervention strategies have been developed by leveraging existing molecular biology knowledge and combining it with nanotechnology tools to improve outcomes. However, little attention has been paid to harnessing the strengths of nanotechnology as a biological discovery tool. Fundamental understanding of controlling dynamic biological processes at the subcellular level is key to developing personalized therapeutic and diagnostic interventions. Single-cell analyses using intravital microscopy, expansion microscopy, and microfluidic-based platforms have been helping to better understand cell heterogeneity in healthy and diseased cells, a major challenge in oncology. Also, single-cell analysis has revealed critical signaling pathways and biological intracellular components with key biological functions. The physical manipulation enabled by nanotools can allow real-time monitoring of biological changes at a single-cell level by sampling intracellular fluid from the same cell. The formation of intercellular highways by nanotube-like structures has important clinical implications such as metastasis development. The integration of nanomaterials into optical and molecular imaging techniques has rendered valuable morphological, structural, and biological information. Nanoscale imaging unravels mechanisms of temporality by enabling the visualization of nanoscale dynamics never observed or measured between individual cells with standard biological techniques. The exceptional sensitivity of nanozymes, artificial enzymes, make them perfect components of the next-generation mobile diagnostics devices. Here, we highlight these impactful cancer-related biological discoveries enabled by nanotechnology and producing a paradigm shift in cancer research and oncology.

Appropriate Size of Fe3O4 Nanoparticles for Cancer Therapy by Ferroptosis

Iron oxide nanoparticles can induce cell death due to the ferroptosis mechanism, showing a great potential for cancer therapy. Here, we synthesized different-sized iron oxide nanoparticles (2-100 nm) to investigate their antitumor effect and toxicity mechanism. It was found that ultrasmall nanoparticles (< ∼5 nm) could accumulate in nucleus and were more efficient in triggering the generation of ^•OH than larger nanoparticles due to the quicker release of Fe²⁺, thus exhibiting more remarkable cytotoxicity. Nevertheless, 10 nm iron oxide nanoparticles group displayed the best antitumor effect in vivo. We studied the in vivo and intratumoral biodistribution of the nanoparticles and found that the therapeutic effects were related to both the tumoral accumulation and intratumoral distribution of nanoparticles. This work indicates the appropriate size of Fe₃O₄ NPs for cancer treatment and illustrates the possible factors that influence the therapeutic effect, suggesting the great potential of iron oxide in clinical application.

Joint synovial macrophages as a potential target for intra-articular treatment of osteoarthritis-related pain

Osteoarthritis is the most common form of joint disease and is one of the leading causes of chronic pain. Given the multi-factorial nature, numerous efforts have been made to clarify the multiple factors impacting the pain symptoms and joint pathology, including synovial macrophages in particular. Accumulating evidence from studies involving human participants and experimental animal models suggests that accumulating macrophages in synovial tissue are implicated in peripherally mediated pain sensitization of affected joints in osteoarthritis. Crosstalk between synovial macrophages and the innervating primary nociceptive neurons is thought to contribute to this facilitated pain processing by the peripheral nervous system. Due to high plasticity and complexity of synovial macrophages in the joint, safe therapies targeting single cells or molecules are currently lacking. Using advanced technologies (such as single-cell RNA sequencing and mass cytometry), studies have shown that diverse subpopulations of synovial macrophages exist in the distinct synovial microenvironments of specific osteoarthritis subtypes. Considerable progress has been made in delineating the molecular mechanisms of various subsets of synovial macrophages in the development of osteoarthritis. To develop a novel intra-articular treatment paradigm targeting synovial macrophages, we have summarized in this review the recent advances in identifying the functional consequences of synovial macrophage sub-populations and understanding of the molecular mechanisms driving macrophage-mediated remodeling.