Natural compounds that regulate lymph node sinus macrophages: Inducing an anti-tumor effect by regulating macrophage activation

Naringenin counteracts LPS-induced inflammation and immune deficits in chicken thymus by alleviating mtROS/ferroptosis levels

Naringenin is a flavonoid with significant anti-inflammatory and antioxidant properties. Mitochondrial dynamics, the mitochondrial respiratory chain, and mtROS are closely related to each other and regulate various biological processes. Ferroptosis is closely related to inflammatory responses and immune function in multiple tissues and organs. However, whether naringenin can alleviate LPS-induced inflammation and immune disorders in the chicken thymus via mtROS/ferroptosis has not been reported. Therefore, in this study, we constructed chicken thymus and MSB-1 cell models of LPS and naringenin based on screening for naringenin concentrations that have positive effects on inflammation and immune function to further investigate the anti-inflammatory, antiferroptosis, and maintenance of the immune function of naringenin. The results showed that 40 mg/kg naringenin alleviated LPS-induced tissue damage, elevated serum inflammatory factors, and decreased serum immune factors. The mechanism by which naringenin attenuates mtROS release by alleviating the imbalance of mitochondrial dynamics and the blockage of the respiratory chain. The effect of naringenin on alleviating LPS-induced lipid peroxidation, disruption of the GSH/GSSG system, iron overload, and GPx4 inactivation, thereby attenuating ferroptosis in thymus tissue, was inhibited by the addition of mtROS activators. In conclusion, naringenin alleviates LPS-induced ferroptosis in chicken thymus by attenuating mtROS release.

Cytotoxic, antioxidant, and antiglycation activities, and tyrosinase inhibition using silver nanoparticles synthesized by leaf extract of Solanum aculeatissimum Jacq

The present study aimed to determine the biological properties of an extract of Solanum aculeatissimum aqueous extract (SaCE) alone as well as silver nanoparticles (AgNPs) generated by green synthesis utilizing S. aculeatissimum aqueous extract (SaCE). These synthesized SaCE AgNPs were characterized using UV-VIS spectrophotometry, scanning transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS), zeta potential (ZP), dynamic light scattering (DLS). Determination of total polyphenols, flavonoids, saponins content was conducted. In addition, high performance liquid chromatography-mass spectrometry (HPLC-MS) was employed to identify constituents in this extract. Antioxidant activity was determined by DPPH radical scavenging and ferric ion reducing power (FRAP) methods. Antiglycation activity was demonstrated through relative mobility in electrophoresis (RME) and determination of free amino groups. The inhibitory activity on tyrosinase was also examined. Molecular docking analyses were performed to assess the molecular interactions with DNA and tyrosinase. The antitumor activity SaCE was also measured. Phytochemical analysis of SaCE and AgNPs showed presence polyphenols (1000.41 and 293.37 mg gallic acid equivalent/g), flavonoids (954.87 and 479.87 mg rutin equivalent/g), saponins (37.89 and 23.01% total saponins), in particular steroidal saponins (aculeatiside A and B). Both SaCE and AgNPs exhibited significant antioxidant (respectively, 73.97%, 56.27% in DPPH test, 874.67 and 837.67 μM Trolox Equivalent/g in FRAP test) and antiglycation activities (72.81 and 67.98% free amino groups, results observed in RME). SaCE and AgNPs presented 33.2, 36.1% inhibitory activity on tyrosinase, respectively. In silico assay demonstrated interaction between steroidal saponins, DNA or tyrosinase. SaCE exhibited antitumor action against various human tumor cells. Data demonstrated that extracts SaCE alone and AgNPs synthesized from SaCE presented biological properties of interest for application in new therapeutic formulations in medicine.

Dysfunction of sinus macrophages in tumor-bearing host induces resistance to immunotherapy

Sinus macrophages in draining lymph nodes (DLNs) are involved in anti-tumor immune reactions. CD169 (Sialoadhesin, Siglec-1) is expressed on sinus macrophages and is considered a surrogate marker for the immunostimulatory phenotype of macrophages. In this study, the significance of sinus macrophages in immunotherapy was evaluated using mouse models. Treatment with anti-programmed death-ligand 1 (PD-L1) antibody suppressed the subcutaneous tumor growth of MC38 and E0771 cells but was not effective against MB49 and LLC tumors. Decreased cytotoxic T-lymphocyte (CTL) infiltration in tumor tissues and CD169 expression in sinus macrophages were observed in MB49 and LLC cells compared to corresponding parameters in MC38 and E0771 cells. The anti-tumor effects of the anti-PD-L1 antibody on MC38 and E0771 cells were abolished when sinus macrophages in DLNs were depleted, suggesting that sinus macrophages are involved in the therapeutic effect of the anti-PD-L1 antibody. Naringin activated sinus macrophages. Naringin inhibited tumor growth in MB49- and LLC-bearing mice but did not affect that in MC38- and E0771-bearing mice. The infiltration of CTLs in tumor tissues and their activation were increased by naringin, and this effect was impaired when sinus macrophages were depleted. Combination therapy with naringin and anti-PD-L1 antibody suppressed MB49 tumor growth. In conclusion, CD169-positive sinus macrophages in DLNs are critical for anti-tumor immune responses, and naringin suppresses tumor growth by activating CD169-positive sinus macrophages and anti-tumor CTL responses. The activation status of sinus macrophages has been suggested to differ among tumor models, and this should be investigated in future studies.

Anticancer immune reaction and lymph node sinus macrophages: a review from human and animal studies

Lymph nodes are secondary lymphoid organs localized throughout the body that typically appear as bean-like nodules. Numerous antigen-presenting cells, including dendritic cells and macrophages, that mediate host defense responses against pathogens, such as bacteria and viruses, reside within lymph nodes. To react to cancer cell-derived antigens in a variety of cancers, antigen-presenting cells induce cytotoxic T lymphocytes (CTLs). In relation to anticancer immune responses, macrophages in the lymph node sinus have been of particular interest because a number of studies involving both human specimens and animal models have reported that lymph node macrophages expressing CD169 play a key role in activating anticancer CTLs. Recent studies have indicated that dysfunction of lymph node macrophages potentially contributes to immune suppression in elderly patients and immunological "cold" tumors. Therefore, in anticancer therapy, the regulation of lymph node macrophages is a potentially promising approach.

Mechanisms and characteristics of subcapsular sinus macrophages in tumor immunity: a narrative review

Background and Objective

Lymph nodes constitute an integral component of the secondary lymphoid organs, housing a diverse population of macrophages. Macrophages exhibit heterogeneity in terms of localization, phenotype and ontogeny. Recent evidence has established that subcapsular sinus macrophages (SCSMs) are the initial cells exposed to antigens from afferent lymph vessels, playing a crucial role in the host immune response against invading pathogens and tumor cells. In order to summarize the role and mechanisms of SCSM in tumor immunity, this study systematically reviews research on SCSMs in tumor immunity.

Methods

A systematic search was conducted in PubMed and Web of Science to identify articles investigating clinical significance and mechanisms of SCSMs. Study eligibility was independently evaluated by two authors based on the assessment of titles, abstracts and full-texts.

Key Content and Findings

The narrative review included a total of 17 studies. Previous research consistently showed that a high level of SCSM in patients with various carcinomas is associated with a favorable long-term prognosis. SCSM acts as the front-line defender in antitumor activity, engaging in intricate communication with other immune cells. Moreover, SCSM could directly and indirectly modulate tumor immunity, and the integrity of SCSM layer is interrupted in disease status. Several studies explored the feasibility of targeting SCSM to activate immunity against tumors. However, the direct molecular interactions and alternation in signal pathway in the tumor immunity of SCSM are less well established in previous researches.

Conclusions

This narrative review underscores the critical role of SCSM in tumor immunity. Future studies should focus on the deeper mechanism underlying SCSMs and explore their clinical applications.

Hairy root culture: a potent method for improved secondary metabolite production of Solanaceous plants

Secondary metabolites synthesized by the Solanaceous plants are of major therapeutic and pharmaceutical importance, many of which are commonly obtained from the roots of these plants. 'Hairy roots', mirroring the same phytochemical pattern of the corresponding root of the parent plant with higher growth rate and productivity, are therefore extensively studied as an effective alternative for the in vitro production of these metabolites. Hairy roots are the transformed roots, generated from the infection site of the wounded plants with Agrobacterium rhizogenes. With their fast growth, being free from pathogen and herbicide contamination, genetic stability, and autotrophic nature for plant hormones, hairy roots are considered as useful bioproduction systems for specialized metabolites. Lately, several elicitation methods have been employed to enhance the accumulation of these compounds in the hairy root cultures for both small and large-scale production. Nevertheless, in the latter case, the cultivation of hairy roots in bioreactors should still be optimized. Hairy roots can also be utilized for metabolic engineering of the regulatory genes in the metabolic pathways leading to enhanced production of metabolites. The present study summarizes the updated and modern biotechnological aspects for enhanced production of secondary metabolites in the hairy root cultures of the plants of Solanaceae and their respective importance.

Research progress on the anti-tumor effect of Naringin

Naringin is a kind of natural dihydro flavone, which mainly exists in citrus fruits of the Rutaceae family, as well as traditional Chinese medicines such as trifoliate orange, fingered citron, exocarpium citri grandis, and rhizoma dynamite. Modern pharmacological studies have shown that Naringin has excellent anti-tumor activity. Through reviewing the relevant literature at home and abroad in recent years, we summarized the pharmacological mechanism of Naringin to play an anti-cancer role in blocking tumor cell cycle, inhibiting tumor cell proliferation, inducing tumor cell apoptosis, inhibiting tumor cell invasion and metastasis, inducing tumor cell autophagy, reversing tumor cell drug resistance and enhancing chemotherapeutic drug sensitivity, as well as anti-inflammatory to prevent canceration, alleviate Adverse drug reaction of chemotherapy, activate and strengthen immunity, It provides theoretical basis and reference basis for further exploring the anticancer potential of Naringin and its further development and utilization.

Naringenin potentiates anti-tumor immunity against oral cancer by inducing lymph node CD169-positive macrophage activation and cytotoxic T cell infiltration

The CD169⁺ macrophages in lymph nodes are implicated in cytotoxic T lymphocyte (CTL) activation and are associated with improved prognosis in several malignancies. Here, we investigated the significance of CD169⁺ macrophages in oral squamous cell carcinoma (OSCC). Further, we tested the anti-tumor effects of naringenin, which has been previously shown to activate CD169⁺ macrophages, in a murine OSCC model. Immunohistochemical analysis for CD169 and CD8 was performed on lymph node and primary tumor specimens from 89 patients with OSCC. We also evaluated the effects of naringenin on two murine OSCC models. Increased CD169⁺ macrophage counts in the regional lymph nodes correlated with favorable prognosis and CD8⁺ cell counts within tumor sites. Additionally, naringenin suppressed tumor growth in two murine OSCC models. The mRNA levels of CD169, interleukin (IL)-12, and C-X-C motif chemokine ligand 10 (CXCL10) in lymph nodes and CTL infiltration in tumors significantly increased following naringenin administration in tumor-bearing mice. These results suggest that CD169⁺ macrophages in lymph nodes are involved in T cell-mediated anti-tumor immunity and could be a prognostic marker for patients with OSCC. Moreover, naringenin is a new potential agent for CD169⁺ macrophage activation in OSCC treatment.

Tumor-associated macrophages: Potential target of natural compounds for management of breast cancer

A large body of experimental research reveals that tumor-associated macrophages (TAMs) are the major immunosuppressor cells in the breast tumor microenvironment (TME). The infiltration of macrophages is correlated with inverse outcomes like disease-free survival and overall survival of cancer patients. They are responsible for heterogeneity, metastasis, and drug resistance. Further, their density in tumor beds is correlated with stage and therapy response. The current review is aimed at summarizing mechanisms and signaling pathways that modulate immune-suppressive phenotype and expansion of TAMs. The review presents an overview of the interdependence of tumor cells and TAMs in TME to promote metastasis, drug resistance and immune suppressive phenotype. This review also presents the potential natural compounds that modulate the immune-suppressive functions of TAMs and their signaling pathways. Finally, this review provides nanotechnology approaches for the targeted delivery of natural products. This review shed light on BC management including clinical studies on the prognostic relevance of TAMs and natural compounds that sensitizes BC.

Subtilase cytotoxin from Shiga-toxigenic Escherichia coli impairs the inflammasome and exacerbates enteropathogenic bacterial infection

Subtilase cytotoxin (SubAB) is an AB₅ toxin mainly produced by the locus of enterocyte effacement-negative Shiga-toxigenic Escherichia coli (STEC) strain such as O113:H21, yet the contribution of SubAB to STEC infectious disease is unclear. We found that SubAB reduced activation of the STEC O113:H21 infection-induced non-canonical NLRP3 inflammasome and interleukin (IL)-1β and IL-18 production in murine macrophages. Downstream of lipopolysaccharide signaling, SubAB suppressed caspase-11 expression by inhibiting interferon-β/STAT1 signaling, followed by disrupting formation of the NLRP3/caspase-1 assembly. These inhibitions were regulated by PERK/IRE1α-dependent endoplasmic reticulum (ER) stress signaling initiated by cleavage of the host ER chaperone BiP by SubAB. Our murine model of SubAB-producing Citrobacter rodentium demonstrated that SubAB promoted C. rodentium proliferation and worsened symptoms such as intestinal hyperplasia and diarrhea. These findings highlight the inhibitory effect of SubAB on the NLRP3 inflammasome via ER stress, which may be associated with STEC survival and infectious disease pathogenicity in hosts.

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SubAB from STEC inhibits inflammasome activation and IL-1β/IL-18 production

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SubAB prevents caspase-11 expression via IRE1α/PERK-dependent inhibition of STAT1

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SubAB reduces LPS-induced pro-IL-1β production via IRE1α/PERK-dependent pathway

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SubAB promotes C. rodentium survival in mouse colon and facilitates the infection

Immunoregulatory properties of a crude extraction fraction rich in polysaccharide from Chrysanthemum zawadskii Herbich var. latilobum and its potential role as a vaccine adjuvant

The objective of the current study was to demonstrate the immunostimulatory effects of a polysaccharide isolated from Chrysanthemum zawadskii Herbich var. latilobum leaves (CP) and evaluate its potential as a vaccine adjuvant. Results showed that CP induced maturation of the dendritic cells (DCs). In addition, CP-treated DCs activated naïve T cells to polarized CD4+ and CD8+ T cells and substantially induced the production of IFN-γ and IL-2 in vitro. Furthermore, CP initiated the maturation of DCs via the activation of MAPK and NF-κB signaling pathways. Interestingly, systemic administration of CP-treated DCs pulsed with ovalbumin (OVA) peptides significantly enhanced the immune response in vivo, which included the generation of antigen (OVA)-specific polyfunctional T cells, increased cytotoxic T lymphocyte activity, induction of Th1-mediated humoral immunity, and suppression of tumor growth. Taken together, our study highlighted the immunoregulatory activity of CP as well as its potential as a candidate vaccine adjuvant.

Targeting the tumor immune microenvironment with "nutraceuticals": From bench to clinical trials

The occurrence of immune effector cells in the tissue microenvironment during neoplastic progression is critical in determining tumor growth outcomes. On the other hand, tumors may also avoid immune system-mediated elimination by recruiting immunosuppressive leukocytes and soluble factors, which coordinate a tumor microenvironment that counteracts the efficiency of the antitumor immune response. Checkpoint inhibitor therapy results have indicated a way forward via activation of the immune system against cancer. Widespread evidence has shown that different compounds in foods, when administered as purified substances, can act as immunomodulators in humans and animals. Although there is no universally accepted definition of nutraceuticals, the term identifies a wide category of natural compounds that may impact health and disease statuses and includes purified substances from natural sources, plant extracts, dietary supplements, vitamins, phytonutrients, and various products with combinations of functional ingredients. In this review, we summarize the current knowledge on the immunomodulatory effects of nutraceuticals with a special focus on the cancer microenvironment, highlighting the conceptual benefits or drawbacks and subtle cell-specific effects of nutraceuticals for envisioning future therapies employing nutraceuticals as chemoadjuvants.

Targeting Lymph Node Sinus Macrophages to Inhibit Lymph Node Metastasis

Lymph nodes are important peripheral immune organs in which numerous important immune responses occur. During the process of lymphatic metastasis, lymph nodes are also sites through which tumor cells must pass. Therefore, it is essential to develop a drug delivery system that can specifically transfer immunostimulatory medicine into lymph nodes to block lymphatic metastasis. Here, we developed a nucleic acid drug delivery system containing cationic agarose (C-agarose) and CpG oligodeoxynucleotides. C-agarose has a high affinity for Siglec-1 on the surface of lymph node sinus macrophages, which have a high specificity for targeting lymph nodes. Subcutaneous implantation of C-agarose+CpG gel caused the accumulation of CpG in the lymph node sinus macrophages and generated antitumor immune responses in the lymph node. C-agarose+CpG gel treatment decreased the metastasis size in the tumor-draining lymph node (TDLN) and lung metastatic nodules and suppressed tumor growth in both a mouse 4T1 breast cancer model and a B16F10 melanoma model. On this basis, this study proposes a nonsurgical invasive lymph node targeting immunotherapy concept that may provide a new approach for antitumor metastasis.

Preparation of fibrin hydrogels to promote the recruitment of anti-inflammatory macrophages

Macrophages play an important role in regulating inflammation and tissue regeneration. In the present study, uniform fibrin hydrogel scaffolds were engineered in millimeters. These scaffolds induced anti-inflammatory macrophages to digest and infiltrate the scaffold. The culture conditions of the fibrin hydrogels decreased the secretion of tumor necrosis factor-α (TNF-α), a pro-inflammatory cytokine, and increased the secretion of interleukin-10 (IL-10), an anti-inflammatory cytokine, in mouse bone marrow-derived macrophages. Similar results were also observed in human monocyte-derived macrophages (HMDMs). In addition, most of cells that infiltrated the fibrin hydrogels were macrophages expressing CD163, CD204, and CD206, which are anti-inflammatory macrophages markers, both in mice and in human cells. Therefore, to induce increased macrophage infiltration, we attempted to combine fibrin hydrogels with SEW2871, a monocyte/macrophage recruitment agent that is known to be a sphingosine-1 phosphate receptor 1 agonist, solubilized in water by micelle formation with a cholesterol-grafted gelatin. However, the fibrin hydrogels alone retained the same monocyte migration activity as the hydrogels with SEW2871-incorporated micelles in the hydrogel-bearing mouse model. These findings indicate that fibrin hydrogels have a strong promoting effect on the recruitment of anti-inflammatory macrophages. Therefore, fibrin hydrogels may be an optimal biomaterial in the design of medicines for macrophage-induced regenerative therapies. STATEMENT OF SIGNIFICANCE: The immune response to tissue injury is important for determining the speed and the result of the regeneration. Alternatively activated macrophages (M2 macrophages) resolve inflammatory response and promote tissue repair by producing anti-inflammatory factors. Promoting the recruitment of macrophages is a hopeful strategy in the design of biomaterials for tissue regeneration. In the present study, we combined the fibrin hydrogel, which promotes anti-inflammatory polarization, with a macrophage recruitment agent. We revealed that the fibrin hydrogel significantly promoted anti-inflammatory polarization in mouse in vivo and human in vitro. Moreover, macrophages significantly infiltrated into the fibrin hydrogel regardless of the agent combination. Fibrin hydrogels may become a reliable biomaterial for tissue regeneration, and the present study is believed to provide information for many researchers.

High CD169 expression in lymph node macrophages predicts a favorable clinical course in patients with esophageal cancer

Recent findings indicate CD169-positive lymph node sinus macrophages (LySMs) in the regional lymph nodes (RLNs) play an important role in anti-cancer immunity. In the present study, we investigated the correlation between CD169 expression in RLNs and clinicopathologic factors. Higher CD169 expression in LySMs was significantly associated with longer cancer-specific survival (CSS). The density of tumor-infiltrating lymphocytes (TILs) in the cancer nest and CD169 expression on LySMs were positively associated in patients who underwent pretreatment. As CD169 expression is thought to reflect a high interferon signature in RLNs, we tried to identify immunity-related genes that are up-regulated by interferon in macrophages as well as CD169. Indoleamine 2,3-dioxygenase (IDO1) was found to be elevated by interferon, and expression of IDO1 was tested using immunohistochemistry. IDO1 expression on LySMs was positively correlated with CD169 expression; however, there was no significant correlation between IDO1 and clinicopathologic factors. These results suggest that high expression of CD169 in LySMs reflects a high potential for anti-cancer immune responses in esophageal cancer patients and that monitoring CD169 expression would be useful for evaluating the potential of anti-cancer immune reactions.