Evolutionary Aspects of Macrophages Polarization

Macrophage dynamics in prostate cancer: Molecular to therapeutic insights

This review provides an in-depth examination of the role that tumor-associated macrophages (TAMs) play in the progression of prostate cancer (PCa), with a particular focus on the factors influencing the polarization of M1 and M2 macrophages and the implications of targeting these cells for cancer progression. The development and prognosis of PCa are significantly influenced by the behavior of macrophages within the tumor microenvironment. M1 macrophages typically exhibit anti-tumor properties by secreting pro-inflammatory cytokines such as interferon-gamma (IFN-γ) and tumor necrosis factor-alpha (TNF-α), thereby enhancing the immune response. Conversely, M2 macrophages contribute to tumor cell migration and invasion through the production of factors like arginase-1 (Arg1) and interleukin-10 (IL-10). This review not only explores the diverse factors that affect macrophage polarization but also delves into the potential therapeutic strategies targeting macrophage polarization, including the critical roles of non-coding RNA and exosomes in regulating this process. The polarization state of macrophages is highlighted as a key determinant in PCa progression, offering a novel perspective for clinical treatment. Future research should concentrate on gaining a deeper understanding of the molecular mechanisms underlying macrophage polarization and on developing effective targeted therapeutic strategies. The exploration of the potential of combination therapies to improve treatment efficacy is also emphasized. By emphasizing the importance of macrophages as a therapeutic target in PCa, this review aims to provide valuable insights and research directions for clinicians and researchers.

Role of microglia/macrophage polarisation in intraocular diseases (Review)

Macrophages form a crucial component of the innate immune system, and their activation is indispensable for various aspects of immune and inflammatory processes, tissue repair, and maintenance of the balance of the body's state. Macrophages are found in all ocular tissues, spanning from the front surface, including the cornea, to the posterior pole, represented by the choroid/sclera. The neural retina is also populated by specialised resident macrophages called microglia. The plasticity of microglia/macrophages allows them to adopt different activation states in response to changes in the tissue microenvironment. When exposed to various factors, microglia/macrophages polarise into distinct phenotypes, each exhibiting unique characteristics and roles. Furthermore, extensive research has indicated a close association between microglia/macrophage polarisation and the development and reversal of various intraocular diseases. The present article provides a review of the recent findings on the association between microglia/macrophage polarisation and ocular pathological processes (including autoimmune uveitis, optic neuritis, sympathetic ophthalmia, retinitis pigmentosa, glaucoma, proliferative vitreoretinopathy, subretinal fibrosis, uveal melanoma, ischaemic optic neuropathy, retinopathy of prematurity and choroidal neovascularization). The paradoxical role of microglia/macrophage polarisation in retinopathy of prematurity is also discussed. Several studies have shown that microglia/macrophages are involved in the pathology of ocular diseases. However, it is required to further explore the relevant mechanisms and regulatory processes. The relationship between the functional diversity displayed by microglia/macrophage polarisation and intraocular diseases may provide a new direction for the treatment of intraocular diseases.

Infection biology of Salmonella enterica

Salmonella enterica is the leading cause of bacterial foodborne illness in the USA, with an estimated 95% of salmonellosis cases due to the consumption of contaminated food products. Salmonella can cause several different disease syndromes, with the most common being gastroenteritis, followed by bacteremia and typhoid fever. Among the over 2,600 currently identified serotypes/serovars, some are mostly host-restricted and host-adapted, while the majority of serotypes can infect a broader range of host species and are associated with causing both livestock and human disease. Salmonella serotypes and strains within serovars can vary considerably in the severity of disease that may result from infection, with some serovars that are more highly associated with invasive disease in humans, while others predominantly cause mild gastroenteritis. These observed clinical differences may be caused by the genetic make-up and diversity of the serovars. Salmonella virulence systems are very complex containing several virulence-associated genes with different functions that contribute to its pathogenicity. The different clinical syndromes are associated with unique groups of virulence genes, and strains often differ in the array of virulence traits they display. On the chromosome, virulence genes are often clustered in regions known as Salmonella pathogenicity islands (SPIs), which are scattered throughout different Salmonella genomes and encode factors essential for adhesion, invasion, survival, and replication within the host. Plasmids can also carry various genes that contribute to Salmonella pathogenicity. For example, strains from several serovars associated with significant human disease, including Choleraesuis, Dublin, Enteritidis, Newport, and Typhimurium, can carry virulence plasmids with genes contributing to attachment, immune system evasion, and other roles. The goal of this comprehensive review is to provide key information on the Salmonella virulence, including the contributions of genes encoded in SPIs and plasmids during Salmonella pathogenesis.

EBV Impact in Peripheral Macrophages' Polarization Cytokines in Pediatric Patients

Macrophages are exceptionally flexible cells. The presence of inflammatory cytokines such as IFN-γ and TNF-α results in an M1 (CD68) activation, while cytokines such as IL-10 or TGF-β induce the M2 (CD163) activation. Our aim was to study the behavior of peripheral cytokines involved in macrophage polarization and relate them with tissue findings to further comprehend the role of macrophages in EBV pediatric infection. We studied cytokine expression in tonsils and peripheral blood samples of children in different stages of infection. Peripheral cytokines were compared with macrophage polarization markers and viral protein expression in tonsils. Only IL-10 showed a negative correlation between compartments, exclusively in patients undergoing viral reactivation (R). Higher expressions of peripheral IL-1β, IL-23, and IL-12p40 in R children were observed. Lower expressions of local and peripheral TNF-α in patients with broader expressions of latent and lytic viral proteins were demonstrated. In healthy carrier (HC) patients, IL-23 positively correlated with CD163, and IP-10 positively correlated with CD68. Our results indicated that EBV might modulate antigen expression in the presence of TNF-α and influence peripheral cytokine expression differently in each stage of infection. Moreover, peripheral cytokines might have a particular role in macrophage polarization in HC.

Polarizing Macrophage Functional Phenotype to Foster Cardiac Regeneration

There is an increasing interest in understanding the connection between the immune and cardiovascular systems, which are highly integrated and communicate through finely regulated cross-talking mechanisms. Recent evidence has demonstrated that the immune system does indeed have a key role in the response to cardiac injury and in cardiac regeneration. Among the immune cells, macrophages appear to have a prominent role in this context, with different subtypes described so far that each have a specific influence on cardiac remodeling and repair. Similarly, there are significant differences in how the innate and adaptive immune systems affect the response to cardiac damage. Understanding all these mechanisms may have relevant clinical implications. Several studies have already demonstrated that stem cell-based therapies support myocardial repair. However, the exact role that cardiac macrophages and their modulation may have in this setting is still unclear. The current need to decipher the dual role of immunity in boosting both heart injury and repair is due, at least for a significant part, to unresolved questions related to the complexity of cardiac macrophage phenotypes. The aim of this review is to provide an overview on the role of the immune system, and of macrophages in particular, in the response to cardiac injury and to outline, through the modulation of the immune response, potential novel therapeutic strategies for cardiac regeneration.

Mesenchymal stem cells and macrophages and their interactions in tendon-bone healing

Tendon-bone insertion injuries (TBI), such as anterior cruciate ligament (ACL) and rotator cuff injuries, are common degenerative or traumatic pathologies with a negative impact on the patient's daily life, and they cause huge economic losses every year. The healing process after an injury is complex and is dependent on the surrounding environment. Macrophages accumulate during the entire process of tendon and bone healing and their phenotypes progressively transform as they regenerate. As the "sensor and switch of the immune system", mesenchymal stem cells (MSCs) respond to the inflammatory environment and exert immunomodulatory effects during the tendon-bone healing process. When exposed to appropriate stimuli, they can differentiate into different tissues, including chondrocytes, osteocytes, and epithelial cells, promoting reconstruction of the complex transitional structure of the enthesis. It is well known that MSCs and macrophages communicate with each other during tissue repair. In this review, we discuss the roles of macrophages and MSCs in TBI injury and healing. Reciprocal interactions between MSCs and macrophages and some biological processes utilizing their mutual relations in tendon-bone healing are also described. Additionally, we discuss the limitations in our understanding of tendon-bone healing and propose feasible ways to exploit MSC-macrophage interplay to develop an effective therapeutic strategy for TBI injuries.

The Translational potential of this article

This paper reviewed the important functions of macrophages and mesenchymal stem cells in tendon-bone healing and described the reciprocal interactions between them during the healing process. By managing macrophage phenotypes, mesenchymal stem cells and the interactions between them, some possible novel therapies for tendon-bone injury may be proposed to promote tendon-bone healing after restoration surgery.

Targeting tumor-associated macrophages in hepatocellular carcinoma: biology, strategy, and immunotherapy

Hepatocellular carcinoma (HCC), one of the most malignant tumors, is characterized by its stubborn immunosuppressive microenvironment. As one of the main members of the tumor microenvironment (TME) of HCC, tumor-associated macrophages (TAMs) play a critical role in its occurrence and development, including stimulating angiogenesis, enhancing immunosuppression, and promoting the drug resistance and cancer metastasis. This review describes the origin as well as phenotypic heterogeneity of TAMs and their potential effects on the occurrence and development of HCC and also discusses about various adjuvant therapy based strategies that can be used for targeting TAMs. In addition, we have highlighted different treatment modalities for TAMs based on immunotherapy, including small molecular inhibitors, immune checkpoint inhibitors, antibodies, tumor vaccines, adoptive cellular immunotherapy, and nanocarriers for drug delivery, to explore novel combination therapies and provide feasible therapeutic options for clinically improving the prognosis and quality of life of HCC patients.

Nrf2 orchestrates transition from acute to chronic otitis media through inflammatory macrophages

Introduction

Acute and chronic otitis media (AOM and COM) are common middle ear infections that can lead to hearing loss and other complications. Recent research has shown that both macrophages and nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway are involved in the immune response to and the resolution of otitis media. However, the specific effects of Nrf2 on macrophages in the transition of AOM to COM are not well understood, and a practical approach to prevent this transition by targeting Nrf2/macrophages has not been established.

Methods

In an AOM mouse model using lipopolysaccharide (LPS) injection into the middle ear, middle ear effusion (OME)-macrophages were isolated and analyzed for Nrf2 expression. M2-like polarization of macrophages was induced by Nrf2 activation and its effects on inflammatory resolution were studied by examining inflammatory neutrophils and macrophages, proinflammatory cytokines, and oxidative levels. The survival of human middle ear epithelial cells (HMMECs) co-cultured with Nrf2-modified macrophages was also evaluated. Furthermore, restoration of Nrf2 in macrophages with adeno-associated virus (AAV) vectors was performed to determine the effect on the transition of AOM to COM in experimental mice.

Results

Reduced Nrf2 in OME-macrophages during the recovery phase was associated with uncured AOM or its development into COM, demonstrated by persistent increases in inflammatory neutrophils and macrophages, proinflammatory cytokines, and oxidative levels. Nrf2 activation induced M2-like polarization of macrophages, which improved the survival of co-cultured HMMECs treated with LPS in vitro. Restoration of Nrf2 in OME-derived low-Nrf2-expressing macrophages with AAV vectors significantly inhibited the transition of AOM to COM in experimental mice.

Discussion

Nrf2 in macrophages plays a critical role in the immune response to and resolution of otitis media Restoration of Nrf2 expression in OME-macrophages could be a promising therapeutic approach to prevent the development of COM in AOM patients.

Density dependent regulation of inflammatory responses in macrophages

Macrophage distribution density is tightly regulated within the body, yet the importance of macrophage crowding during in vitro culture is largely unstudied. Using a human induced pluripotent stem cell (iPSC)-derived macrophage model of tissue resident macrophages, we characterize how increasing macrophage culture density changes their morphology and phenotype before and after inflammatory stimulation. In particular, density drives changes in macrophage inflammatory cytokine and chemokine secretion in both resting and activated states. This density regulated inflammatory state is also evident in blood monocyte derived-macrophages, the human monocytic THP-1 immortalized cell line, and iPSC-derived microglia. Density-dependent changes appear to be driven by a transferable soluble factor, yet the precise mechanism remains unknown. Our findings highlight cell plating density as an important but frequently overlooked consideration of in vitro macrophage research relevant to a variety of fields ranging from basic macrophage cell biology to disease studies.

Macrophage polarity and wound age determination

We investigated the dynamics of the gene expression of M1 and M2 macrophage markers during skin wound healing in mice. Expression of M1-macrophage markers, such as Il12a, Tnf, Il6, Il1b, and Nos2 was upregulated after wounding and peaked at 1 or 3 days after injury, and that of M2-macrophage markers such as Mrc1, Cd163, Ccl17, Arg, and Tgfb1, peaked at 6 days after injury. Consistent with these findings, using triple-color immunofluorescence analysis revealed that F4/80⁺CD80⁺ M1 macrophages were more abundant than F4/80⁺CD206⁺ M2 macrophages on day 3 in mouse wound specimens, and that M2 macrophages were prominently detected in day 6 wounds. For application in forensic practice, we examined macrophage polarization using human wound specimens. The average ratios of CD68⁺iNOS⁺ M1 macrophages to CD68⁺CD163⁺ M2 macrophages (M1/M2 ratios) were greater than 2.5 for the wounds aged 2-5 days. Out of 11 wounds aged 1-5 days, five samples had the M1/M2 ratios of > 3.0. These observations propose that the M1/M2 ratios of 3.0 would indicate a wound age of 1-5 days as the forensic opinion. This study showed that M1 and M2 macrophages in human skin wound might be a promising marker for wound age determination.

Macrophage Polarization and Alveolar Bone Healing Outcome: Despite a Significant M2 Polarizing Effect, VIP and PACAP Treatments Present a Minor Impact in Alveolar Bone Healing in Homeostatic Conditions

Host inflammatory immune response comprises an essential element of the bone healing process, where M2 polarization allegedly contributes to a favorable healing outcome. In this context, immunoregulatory molecules that modulate host response, including macrophage polarization, are considered potential targets for improving bone healing. This study aims to evaluate the role of the immunoregulatory molecules VIP (Vasoactive intestinal peptide) and PACAP (Pituitary adenylate cyclase activating polypeptide), which was previously described to favor the development of the M2 phenotype, in the process of alveolar bone healing in C57Bl/6 (WT) mice. Experimental groups were submitted to tooth extraction and maintained under control conditions or treated with VIP or PACAP were evaluated by microtomographic (µCT), histomorphometric, immunohistochemical, and molecular analysis at 0, 3, 7, and 14 days to quantify tissue healing and host response indicators at the healing site. Gene expression analysis demonstrates the effectiveness of VIP or PACAP in modulating host response, evidenced by the early dominance of an M2-type response, which was paralleled by a significant increase in M2 (CD206+) in treated groups. However, despite the marked effect of M1/M2 balance in the healing sites, the histomorphometric analysis does not reveal an equivalent/corresponding modulation of the healing process. µCT reveals a slight increase in bone matrix volume and the trabecular thickness number in the PACAP group, while histomorphometric analyzes reveal a slight increase in the VIP group, both at a 14-d time-point; despite the increased expression of osteogenic factors, osteoblastic differentiation, activity, and maturation markers in both VIP and PACAP groups. Interestingly, a lower number of VIP and PACAP immunolabeled cells were observed in the treated groups, suggesting a reduction in endogenous production. In conclusion, while both VIP and PACAP treatments presented a significant immunomodulatory effect with potential for increased healing, no major changes were observed in bone healing outcome, suggesting that the signals required for bone healing under homeostatic conditions are already optimal, and additional signals do not improve an already optimal process. Further studies are required to elucidate the role of macrophage polarization in the bone healing process.

DNA Methylation and Recurrent Pregnancy Loss: A Mysterious Compass?

Recurrent pregnancy loss (RPL) is a common and severe pathological pregnancy, whose pathogenesis is not fully understood. With the development of epigenetics, the study of DNA methylation, provides a new perspective on the pathogenesis and therapy of RPL. The abnormal DNA methylation of imprinted genes, placenta-specific genes, immune-related genes and sperm DNA may, directly or indirectly, affect embryo implantation, growth and development, leading to the occurrence of RPL. In addition, the unique immune tolerogenic microenvironment formed at the maternal-fetal interface has an irreplaceable effect on the maintenance of pregnancy. In view of these, changes in the cellular components of the maternal-fetal immune microenvironment and the regulation of DNA methylation have attracted a lot of research interest. This review summarizes the research progress of DNA methylation involved in the occurrence of RPL and the regulation of the maternal-fetal immune microenvironment. The review provides insights into the personalized diagnosis and treatment of RPL.

Absence of multinucleated giant cell reaction as an indicator of tumor progression in oral tongue squamous cell carcinoma

PURPOSE

The aim of this study was to evaluate the presence and distribution of multinucleated giant cell (MGC) reactions in 61 cases of OTSCC and to verify the association of this microscopic finding with clinicopathological parameters (gender, age, tumor size/extent, regional lymph node metastasis, distant metastasis, clinical stage, and histopathological grade of malignancy).

METHODS

Clinical data were collected from medical records and the histopathological grade of malignancy of OTSCCs was evaluated using the World Health Organization (WHO) grading system. The presence and distribution of MGC reaction in high power fields (HPFs) were evaluated in hematoxylin-eosin-stained histological sections. In all cases containing MGCs, immunohistochemical analysis for CD68 was performed in order to confirm the histiocytic nature of these cells.

RESULTS

Twenty-one (34.4%) cases had MGC reactions, with a higher frequency of the focal distribution pattern (57.1%). All MGCs were immunohistochemically positive for CD68. The absence of MGC reaction was significantly associated with regional lymph node metastasis (PR: 2.75; 95% CI 1.05-7.20; p = 0.027), advanced clinical stage (PR: 3.37; 95% CI 1.28-8.85; p = 0.006), and moderately/poorly differentiated tumors (PR: 3.36; 95% CI 1.51-7.48; p = 0.001). No significant associations were observed between the distribution of MGCs and clinicopathological parameters (p > 0.05).

CONCLUSION

Taken together, the results of this study suggest that the absence of MGC reaction may represent an indicator of tumor progression in OTSCCs.

Mesenchymal stromal cells as carriers of IL-12 reduce primary and metastatic tumors of murine melanoma

Due to immunosuppressive properties and confirmed tropism towards cancer cells mesenchymal stromal cells (MSC) have been used in many trials. In our study we used these cells as carriers of IL-12 in the treatment of mice with primary and metastatic B16-F10 melanomas. IL-12 has confirmed anti-cancer activity, induces a strong immune response against cancer cells and acts as an anti-angiogenic agent. A major limitation of the use of IL-12 in therapy is its systemic toxicity. The aim of the work was to develop a system in which cytokine may be administered intravenously without toxic side effects. In this study MSC were used as carriers of the IL-12. We confirmed antitumor effectiveness of the cells secreting IL-12 (MSC/IL-12) in primary and metastatic murine melanoma models. We observed inhibition of tumor growth and a significant reduction in the number of metastases in mice after MSC/IL-12 administration. MSC/IL-12 decreased vascular density and increased the number of anticancer M1 macrophages and CD8⁺ cytotoxic T lymphocytes in tumors of treated mice. To summarize, we showed that MSC are an effective, safe carrier of IL-12 cytokine. Administered systemically they exert therapeutic properties of IL-12 cytokine without toxicity. Therapeutic effect may be a result of pleiotropic (proinflammatory and anti-angiogenic) properties of IL-12 released by modified MSC.

M2-polarized macrophages mediate wound healing by regulating connective tissue growth factor via AKT, ERK1/2, and STAT3 signaling pathways

BACKGROUND

Timely and sufficient M1 recruitment and M2 polarization are necessary for fibrosis during wound healing. The mechanism of how M2 mediates wound healing is worth exploring. Abnormally up-regulated connective tissue growth factor (CTGF) influences multiple organ fibrosis, including cardiac, pulmonary, hepatic, renal, and cutaneous fibrosis. Previous studies reported that M2 contributed to hepatic and renal fibrosis by secreting CTGF. It is worth discussing if M2 regulates fibrosis through secreting CTGF in wound healing.

METHODS AND RESULTS

We established the murine wound model and inhibited macrophages during proliferation phase with clodronate liposomes in vivo. Macrophages depletion led to down-regulation of wound healing rates, collagen deposition, as well as expression of collagen 1/3 and Ki67. M2 was induced by interleukin-4 (IL-4) and measured by flow cytometry in vitro. Secreted pro-fibrotic and anti-fibrotic factors were tested by enzyme-linked immunosorbent assay (ELISA). M2 was polarized, which producing more CTGF, transforming growth factor-beta1 (TGF-β1), and IL-6, as well as less tumor necrosis factor-α (TNF-α) and IL-10. M2 CTGF gene was blocked using siCTGF. Effects of M2 on fibroblasts activities were detected by cell counting kit 8 (CCK8) and cellular wound healing assay. Expressions of related signaling pathway were assessed by western blotting. Blockade of CTGF in M2 deactivated fibroblasts proliferation and migration by regulating AKT, ERK1/2, and STAT3 pathway. Recombinant CTGF restored these effects.

CONCLUSIONS

Our research, for the first time, indicated that M2 promoted wound healing by secreting CTGF, which further mediating proliferation and migration of fibroblasts via AKT, ERK1/2, and STAT3 pathway.

Specialized Pro-Resolving Mediators Mitigate Cancer-Related Inflammation: Role of Tumor-Associated Macrophages and Therapeutic Opportunities

Inflammation is a fundamental physiological response orchestrated by innate immune cells to restore tissue homeostasis. Specialized pro-resolving mediators (SPMs) are involved in active resolution of inflammation but when inflammation is incomplete, chronic inflammation creates a favorable environment that fuels carcinogenesis and cancer progression. Conventional cancer therapy also strengthens cancer-related inflammation by inducing massive tumor cell death that activate surrounding immune-infiltrating cells such as tumor-associated macrophages (TAMs). Macrophages are key actors of both inflammation and its active resolution due to their plastic phenotype. In line with this high plasticity, macrophages can be hijacked by cancer cells to support tumor progression and immune escape, or therapy resistance. Impaired resolution of cancer-associated inflammation supported by TAMs may thus reinforces tumor progression. From this perspective, recent evidence suggests that stimulating macrophage's pro-resolving functions using SPMs can promote inflammation resolution in cancer and improve anticancer treatments. Thus, TAMs' re-education toward an antitumor phenotype by using SPMs opens a new line of attack in cancer treatment. Here, we review SPMs' anticancer capacities with special attention regarding their effects on TAMs. We further discuss how this new therapeutic approach could be envisioned in cancer therapy.

Systems Pharmacology-Based Dissection of Anti-Cancer Mechanism of Traditional Chinese Herb Saussurea involucrata

Cancer has the highest mortality in humans worldwide, and the development of effective drugs remains a key issue. Traditional Chinese medicine Saussurea involucrata (SI) exhibits a series of effects, such as anti-cancer, but the action mechanisms are still unclear. Here, systems pharmacology was applied to reveal its anti-cancer mechanism. First, we screened the active compounds of SI. Then, the compound–target network, target–disease network, and target–pathway network were constructed. DAVID was applied for GOBP analysis and KEGG pathway enrichment analysis on cancer-related targets. Seven potential compounds and 187 targets were identified. The target–disease classification network showed that compounds mainly regulated proteins related to cancer, nervous system diseases, and cardiovascular system diseases. Also, SI anti-tumor effect mainly associated with the regulation of NO production, angiogenesis, MAPK, and PKB from GOBP enrichment. Additionally, KEGG pathway enrichment indicated that targets involved in anti-inflammatory action, inhibiting angiogenesis and anti-proliferation or inducing apoptosis. Experimental validation showed that four active compounds could inhibit cell proliferation and promote apoptosis in A549 (except for kaempferol), PC-3, and C6 cells. This study not only provides experimental evidence for further research on SI in cancer treatment but also promotes the development of potential drugs of SI in modern medicine.

A non-canonical type 2 immune response coordinates tuberculous granuloma formation and epithelialization

The central pathogen-immune interface in tuberculosis is the granuloma, a complex host immune structure that dictates infection trajectory and physiology. Granuloma macrophages undergo a dramatic transition in which entire epithelial modules are induced and define granuloma architecture. In tuberculosis, relatively little is known about the host signals that trigger this transition. Using the zebrafish-Mycobacterium marinum model, we identify the basis of granuloma macrophage transformation. Single-cell RNA-sequencing analysis of zebrafish granulomas and analysis of Mycobacterium tuberculosis-infected macaques reveal that, even in the presence of robust type 1 immune responses, countervailing type 2 signals associate with macrophage epithelialization. We find that type 2 immune signaling, mediated via stat6, is absolutely required for epithelialization and granuloma formation. In mixed chimeras, stat6 acts cell autonomously within macrophages, where it is required for epithelioid transformation and incorporation into necrotic granulomas. These findings establish the signaling pathway that produces the hallmark structure of mycobacterial infection.

A sweet spot for macrophages: Focusing on polarization

Macrophages are a type of functionally plastic cells that can create a pro-/anti-inflammatory microenvironment for organs by producing different kinds of cytokines, chemokines, and growth factors to regulate immunity and inflammatory responses. In addition, they can also be induced to adopt different phenotypes in response to extracellular and intracellular signals, a process defined as M1/M2 polarization. Growing evidence indicates that glycobiology is closely associated with this polarization process. In this research, we review studies of the roles of glycosylation, glucose metabolism, and key lectins in the regulation of macrophages function and polarization to provide a new perspective for immunotherapies for multiple diseases.

Polarization of Macrophages in Insects: Opening Gates for Immuno-Metabolic Research

Insulin resistance and cachexia represent severe metabolic syndromes accompanying a variety of human pathological states, from life-threatening cancer and sepsis to chronic inflammatory states, such as obesity and autoimmune disorders. Although the origin of these metabolic syndromes has not been fully comprehended yet, a growing body of evidence indicates their possible interconnection with the acute and chronic activation of an innate immune response. Current progress in insect immuno-metabolic research reveals that the induction of insulin resistance might represent an adaptive mechanism during the acute phase of bacterial infection. In Drosophila, insulin resistance is induced by signaling factors released by bactericidal macrophages as a reflection of their metabolic polarization toward aerobic glycolysis. Such metabolic adaptation enables them to combat the invading pathogens efficiently but also makes them highly nutritionally demanding. Therefore, systemic metabolism has to be adjusted upon macrophage activation to provide them with nutrients and thus support the immune function. That anticipates the involvement of macrophage-derived systemic factors mediating the inter-organ signaling between macrophages and central energy-storing organs. Although it is crucial to coordinate the macrophage cellular metabolism with systemic metabolic changes during the acute phase of bacterial infection, the action of macrophage-derived factors may become maladaptive if chronic or in case of infection by an intracellular pathogen. We hypothesize that insulin resistance evoked by macrophage-derived signaling factors represents an adaptive mechanism for the mobilization of sources and their preferential delivery toward the activated immune system. We consider here the validity of the presented model for mammals and human medicine. The adoption of aerobic glycolysis by bactericidal macrophages as well as the induction of insulin resistance by macrophage-derived factors are conserved between insects and mammals. Chronic insulin resistance is at the base of many human metabolically conditioned diseases such as non-alcoholic steatohepatitis, atherosclerosis, diabetes, and cachexia. Therefore, revealing the original biological relevance of cytokine-induced insulin resistance may help to develop a suitable strategy for treating these frequent diseases.

Focusing on the Cell Type Specific Regulatory Actions of NLRX1

Cells utilize a diverse repertoire of cell surface and intracellular receptors to detect exogenous or endogenous danger signals and even the changes of their microenvironment. However, some cytosolic NOD-like receptors (NLR), including NLRX1, serve more functions than just being general pattern recognition receptors. The dynamic translocation between the cytosol and the mitochondria allows NLRX1 to interact with many molecules and thereby to control multiple cellular functions. As a regulatory NLR, NLRX1 fine-tunes inflammatory signaling cascades, regulates mitochondria-associated functions, and controls metabolism, autophagy and cell death. Nevertheless, literature data are inconsistent and often contradictory regarding its effects on individual cellular functions. One plausible explanation might be that the regulatory effects of NLRX1 are highly cell type specific and the features of NLRX1 mediated regulation might be determined by the unique functional activity or metabolic profile of the given cell type. Here we review the cell type specific actions of NLRX1 with a special focus on cells of the immune system. NLRX1 has already emerged as a potential therapeutic target in numerous immune-related diseases, thus we aim to highlight which regulatory properties of NLRX1 are manifested in disease-associated dominant immune cells that presumably offer promising therapeutic solutions to treat these disorders.

Anti-Inflammatory Activity of Extracts and Pure Compounds Derived from Plants via Modulation of Signaling Pathways, Especially PI3K/AKT in Macrophages

The plant kingdom is a source of important therapeutic agents. Therefore, in this review, we focus on natural compounds that exhibit efficient anti-inflammatory activity via modulation signaling transduction pathways in macrophage cells. Both extracts and pure chemicals from different species and parts of plants such as leaves, roots, flowers, barks, rhizomes, and seeds rich in secondary metabolites from various groups such as terpenes or polyphenols were included. Selected extracts and phytochemicals control macrophages biology via modulation signaling molecules including NF-κB, MAPKs, AP-1, STAT1, STAT6, IRF-4, IRF-5, PPARγ, KLF4 and especially PI3K/AKT. Macrophages are important immune effector cells that take part in antigen presentation, phagocytosis, and immunomodulation. The M1 and M2 phenotypes are related to the production of pro- and anti-inflammatory agents, respectively. The successful resolution of inflammation mediated by M2, or failed resolution mediated by M1, may lead to tissue repair or chronic inflammation. Chronic inflammation is strictly related to several disorders. Thus, compounds of plant origin targeting inflammatory response may constitute promising therapeutic strategies.

The Dual Role of Microglia in Blood-Brain Barrier Dysfunction after Stroke

It is well-known that stroke is one of the leading causes of death and disability all over the world. After a stroke, the blood-brain barrier subsequently breaks down. The BBB consists of endothelial cells surrounded by astrocytes. Microglia, considered the long-living resident immune cells of the brain, play a vital role in BBB function. M1 microglia worsen BBB disruption, while M2 microglia assist in repairing BBB damage. Microglia can also directly interact with endothelial cells and affect BBB permeability. In this review, we are going to discuss the mechanisms responsible for the dual role of microglia in BBB dysfunction after stroke.

Cytokine imbalance at materno-embryonic interface as a potential immune mechanism for recurrent pregnancy loss

Recurrent pregnancy loss (RPL) is a prominent reproductive disease that distresses about 2%-5% of couples. RPL is the loss of two or more successive spontaneous pregnancies prior to the 20th week of embryo development. The commencement of pregnancy necessitates implantation of the embryo into responsive maternal decidua synchronized with the process of placentation, decidual and myometrial trophoblast incursion as well as refashioning of spiral blood arteries of uterus. The collapse of any of the processes fundamental for pregnancy success may result into an array of pregnancy problems including spontaneous pregnancy loss. Endometrium of human female manufactures an extensive range of cytokines during the proliferative and secretory stage of the menstrual cycle. These endometrial cytokines are thought as major players for making the uterus ready for embryo implantation and placental development during pregnancy. Decidual cytokines regulate the invasion of trophoblast and remodeling of spiral arteries as well as take part in immune suppression to accomplish the pregnancy. Deterrence of maternal rejection of embryo needs a regulated milieu, which takes place essentially at the embryo-maternal interface and the tissues of the uterus. The reasons of RPL remain anonymous in a large number of cases that lead to difficulties in management and severe trauma in couples. Cytokine modulatory therapies have been shown promising for preventing RPL. Further study of novel factors is wanted to establish more effective RPL treatment protocols. The present study aims to review the outcome of cytokine breach at materno-embryonic interface and the efficacy of cytokine modulatory therapies in RPL.

MicroRNA-301a inhibition enhances the immunomodulatory functions of adipose-derived mesenchymal stem cells by induction of macrophage M2 polarization

MicroRNAs (miRNAs) are a class of short non-coding RNAs that play a significant role in biological processes in various cell types, including mesenchymal stem cells (MSCs). However, how miRNAs regulate the immunomodulatory functions of adipose-derived MSCs (AD-MSCs) remains unknown. Here, we showed that modulation of miR-301a in AD-MSCs altered macrophage polarization. Bone marrow (BM)-derived macrophages were stimulated with LPS (1 μg/ml) and co-cultured with miRNA transfected AD-MSCs for 24 h. The expression of M1 and M2 markers in macrophages was analyzed. Inhibition of miR-301a induced M2 macrophage with arginase-1, CD163, CD206, and IL-10 upregulation. Additionally, toll-like receptor (TLR)-4 mRNA expression in macrophages was downregulated in co-cultures with AD-MSCs transfected with a miR-301a inhibitor. Nitric oxide (NO) in the supernatant of AD-MSC/macrophage co-culture was also suppressed by inhibition of miR-301a in AD-MSCs. We further found that suppression of miR-301a in AD-MSCs increased prostaglandin E₂ (PGE2) concentration in the conditioned medium of the co-culture. Taken together, the results of our study indicate that miR-301a can modulate the immunoregulatory functions of AD-MSCs that favor the applicability as a potential immunotherapeutic agent.

Intracellular Cryptococcus neoformans disrupts the transcriptome profile of M1- and M2-polarized host macrophages

Macrophages serve as a first line of defense against infection with the facultative intracellular pathogen, Cryptococcus neoformans (Cn). However, the ability of these innate phagocytic cells to destroy ingested Cn is strongly influenced by polarization state with classically (M1) activated macrophages better able to control cryptococcal infections than alternatively (M2) activated cells. While earlier studies have demonstrated that intracellular Cn minimally affects the expression of M1 and M2 markers, the impact on the broader transcriptome associated with these states remains unclear. To investigate this, an in vitro cell culture model of intracellular infection together with RNA sequencing-based transcriptome profiling was used to measure the impact of Cn infection on gene expression in both polarization states. The gene expression profile of both M1 and M2 cells was extensively altered to become more like naive (M0) macrophages. Gene ontology analysis suggested that this involved changes in the activity of the Janus kinase-signal transducers and activators of transcription (JAK-STAT), p53, and nuclear factor-κB (NF-κB) pathways. Analyses of the principle polarization markers at the protein-level also revealed discrepancies between the RNA- and protein-level responses. In contrast to earlier studies, intracellular Cn was found to increase protein levels of the M1 marker iNos. In addition, common gene expression changes were identified that occurred post-Cn infection, independent of polarization state. This included upregulation of the transcriptional co-regulator Cited1, which was also apparent at the protein level in M1-polarized macrophages. These changes constitute a transcriptional signature of macrophage Cn infection and provide new insights into how Cn impacts gene expression and the phenotype of host phagocytes.

An Inflamed Human Alveolar Model for Testing the Efficiency of Anti-inflammatory Drugs in vitro

A large number of prevalent lung diseases is associated with tissue inflammation. Clinically, corticosteroid therapies are applied systemically or via inhalation for the treatment of lung inflammation, and a number of novel therapies are being developed that require preclinical testing. In alveoli, macrophages and dendritic cells play a key role in initiating and diminishing pro-inflammatory reactions and, in particular, macrophage plasticity (M1 and M2 phenotypes shifts) has been reported to play a significant role in these reactions. Thus far, no studies with in vitro lung epithelial models have tested the comparison between systemic and direct pulmonary drug delivery. Therefore, the aim of this study was to develop an inflamed human alveolar epithelium model and to test the resolution of LPS-induced inflammation in vitro with a corticosteroid, methylprednisolone (MP). A specific focus of the study was the macrophage phenotype shifts in response to these stimuli. First, human monocyte-derived macrophages were examined for phenotype shifts upon exposure to lipopolysaccharide (LPS), followed by treatment with MP. A multicellular human alveolar model, composed of macrophages, dendritic cells, and epithelial cells, was then employed for the development of inflamed models. The models were used to test the anti-inflammatory potency of MP by monitoring the secretion of pro-inflammatory mediators (interleukin [IL]-8, tumor necrosis factor-α [TNF-α], and IL-1β) through four different approaches, mimicking clinical scenarios of inflammation and treatment. In macrophage monocultures, LPS stimulation shifted the phenotype towards M1, as demonstrated by increased release of IL-8 and TNF-α and altered expression of phenotype-associated surface markers (CD86, CD206). MP treatment of inflamed macrophages reversed the phenotype towards M2. In multicellular models, increased pro-inflammatory reactions after LPS exposure were observed, as demonstrated by protein secretion and gene expression measurements. In all scenarios, among the tested mediators the most pronounced anti-inflammatory effect of MP was observed for IL-8. Our findings demonstrate that our inflamed multicellular human lung model is a promising tool for the evaluation of anti-inflammatory potency of drug candidates in vitro. With the presented setup, our model allows a meaningful comparison of the systemic vs. inhalation administration routes for the evaluation of the efficacy of a drug in vitro.

A Nitric Oxide (NO) Nanoreporter for Noninvasive Real-Time Imaging of Macrophage Immunotherapy

Macrophage-centered therapeutic approaches that rely on immune modulation of tumor associated macrophages (TAMs) from a pro-tumorigenic phenotype (M2) to an anti-tumorigenic phenotype (M1) have facilitated a paradigm shift in macrophage immunotherapy. However, limited clinical success has been achieved due to the low response rates observed in different types of cancers. The ability to measure immune response in real time is critical in order to differentiate responders from non-responders; however, there are currently no platforms to monitor real-time macrophage immunotherapy response. Hence, there is an immediate need to develop imaging techniques that can longitudinally monitor macrophage immunotherapy response. Nitric oxide (NO) produced as a result of activation of macrophages to an anti-tumorigenic state is considered as a hallmark of M1 and can be a direct indication of response. In this study, a NO nanoreporter (NO-NR) is reported that enables real-time monitoring of macrophage immunotherapy drugs in vitro and in vivo. Furthermore, it is observed that sustained inhibition of colony stimulating factor 1 receptor (CSF1R) using a CSF1R inhibitor-NO-NR system leads to enhanced efficacy and better imaging signal. In conclusion, a first-of-its-kind NO nanoreporter tool is reported that can be used as an activatable imaging agent to monitor macrophage immunotherapy response in real time.

(E)-2-Cyano-3-(1H-Indol-3-yl)-N-Phenylacrylamide, a Hybrid Compound Derived from Indomethacin and Paracetamol: Design, Synthesis and Evaluation of the Anti-Inflammatory Potential

The compound (E)-2-cyano-3-(1H-indol-3-yl)-N-phenylacrylamide (ICMD-01) was designed and developed based on the structures of clinically relevant drugs indomethacin and paracetamol through the molecular hybridization strategy. This derivative was obtained by an amidation reaction between substituted anilines and ethyl 2-cyanoacetate followed by a Knoevenagel-type condensation reaction with indole aldehyde that resulted in both a viable synthesis and satisfactory yield. In order to assess the immunomodulatory and anti-inflammatory activity, in vitro assays were performed in J774 macrophages, and significant inhibitions (p < 0.05) of the production of nitrite and the production of cytokines (IL-1β and TNFα) in noncytotoxic concentrations were observed. The anti-inflammatory effect was also studied via CFA-induced paw edema in vivo tests and zymosan-induced peritonitis. In the paw edema assay, ICMD01 (50 mg kg-1) showed satisfactory activity, as did the group treated with dexamethasone, reducing edema in 2-6 h. In addition, there was no significant inhibition of PGE2, IL-1β or TNFα in vivo. Moreover, in the peritonitis assay that assesses leukocyte migration, ICMD-01 exhibited promising results. Therefore, these preliminary studies demonstrate this compound to be a strong candidate for an anti-inflammatory drug together with an improved gastrointestinal safety profile when compared to the conventional anti-inflammatory drugs.

Water Contaminants Associated With Unconventional Oil and Gas Extraction Cause Immunotoxicity to Amphibian Tadpoles

Chemicals associated with unconventional oil and gas (UOG) operations have been shown to contaminate surface and ground water with a variety of endocrine disrupting compounds (EDCs) inducing multiple developmental alteration in mice. However, little is known about the impacts of UOG-associated contaminants on amphibian health and resistance to an emerging ranavirus infectious disease caused by viruses in the genus Ranavirus, especially at the vulnerable tadpole stage. Here we used tadpoles of the amphibian Xenopus laevis and the ranavirus Frog virus 3 (FV3) as a model relevant to aquatic environment conservation research for investigating the immunotoxic effects of exposure to a mixture of 23 UOG-associated chemicals with EDC activity. Xenopus tadpoles were exposed to an equimass mixture of 23 UOG-associated chemicals (range from 0.1 to 10 µg/l) for 3 weeks prior to infection with FV3. Our data show that exposure to the UOG chemical mixture is toxic for tadpoles at ecological doses of 5 to 10 µg/l. Lower doses significantly altered homeostatic expression of myeloid lineage genes and compromised tadpole responses to FV3 through expression of TNF-α, IL-1β, and Type I IFN genes, correlating with an increase in viral load. Exposure to a subset of 6 UOG chemicals was still sufficient to perturb the antiviral gene expression response. These findings suggest that UOG-associated water pollutants at low but environmentally relevant doses have the potential to induce acute alterations of immune function and antiviral immunity.

Carbon Disulfide Induces Embryo Implantation Disorder by Disturbing the Polarization of Macrophages in Mice Uteri

Carbon disulfide (CS₂) induces embryo implantation disorders. Macrophages participate in the process of pregnancy. Therefore, we want to explore the effects of CS₂ exposure on polarization and immune function of macrophages in pregnant mice uteri. The exposure times were gestation days 3 (GD3), 4 (GD4), and 5 (GD5), and the observation end points were arranged in a time series after CS₂ exposure. The uterine tissues were collected to detect the expression levels of macrophages cytokines (IL-6, IL-12, TGF-β1, and Vegf-a) and downstream regulatory cytokines of Th1-type (IL-2 and IFN-γ) and Th2-type (IL-10 and IL-4) by flow cytometry, ELISA, and q-PCR. The results showed that, compared with the controls, the ratios of M1/M2 macrophages in the endometrium significantly increased by 96%, 110%, and 177% at the GD4, GD6, and GD7 observation end points after GD3 exposure and increased about 3.88-fold and 2.37-fold at the GD6 and GD7 observation end points after GD4 exposure, respectively. In contrast, the ratio of M1 and M2 macrophages significantly reduced by 53% at the GD5 observation end point after GD3 exposure. Meanwhile, the expression levels of IL-6 were significantly increased about 2.00-fold for mRNA and 1.60-fold for protein at GD4 observation end points after GD3 exposure, and the mRNA levels of IL-12 increased about 3.61-fold at the GD6 observation end points after GD4 exposure. The mRNA levels of TGF-β1 were significantly decreased by 41%, 25%, and 20% at the GD7 observation end points after exposure at GD3, GD4, and GD5, and the expression levels of Vegf-a mRNA and protein were decreased. Furthermore, the ratio of IL-2/IL4, IL-2/IL-10, IFN-γ/IL-4, and IFN-γ/IL-10 in the uterine tissue was significantly increased at the exposure groups. These findings suggest that the imbalanced polarization of macrophages is the key regulator in the progress of CS₂-induced embryo loss.

Functional aspects, phenotypic heterogeneity, and tissue immune response of macrophages in infectious diseases

Macrophages are a functionally heterogeneous group of cells with specialized functions depending not only on their subgroup but also on the function of the organ or tissue in which the cells are located. The concept of macrophage phenotypic heterogeneity has been investigated since the 1980s, and more recent studies have identified a diverse spectrum of phenotypic subpopulations. Several types of macrophages play a central role in the response to infectious agents and, along with other components of the immune system, determine the clinical outcome of major infectious diseases. Here, we review the functions of various macrophage phenotypic subpopulations, the concept of macrophage polarization, and the influence of these cells on the evolution of infections. In addition, we emphasize their role in the immune response in vivo and in situ, as well as the molecular effectors and signaling mechanisms used by these cells. Furthermore, we highlight the mechanisms of immune evasion triggered by infectious agents to counter the actions of macrophages and their consequences. Our aim here is to provide an overview of the role of macrophages in the pathogenesis of critical transmissible diseases and discuss how elucidation of this relationship could enhance our understanding of the host-pathogen association in organ-specific immune responses.

Olfactory Ensheathing Cells Grafted Into the Retina of RCS Rats Suppress Inflammation by Down-Regulating the JAK/STAT Pathway

The inflammatory microenvironment in the retina plays a vital role in the pathogenesis and progression of retinitis pigmentosa (RP). Microglial inflammatory cytokines production leads to gliosis and apoptosis of retinal neurons, and ultimately, visual loss. Cell-based therapies using grafted olfactory ensheathing cells (OECs) have demonstrated modulation of degenerative microenvironments in the central nervous system (CNS), in a number of animal models. However, mechanisms by which grafted OECs can reduce degeneration in the retina are not well understood. In the present study, we set up an in vitro OEC/BV2 microglia co-culture system, and an in vivo royal college of surgeons (RCS) rat model, used cell transplantation, immunohistochemistry, RT-PCR, western blot to explore the mechanisms by which OECs affect expression of pro- or anti-inflammatory cytokines and polarization of M(IL-6) and M(Arg1) type microglial activation in the retina. We found that compared with the LPS (Lipopolysaccharide) and olfactory nerve fibroblast (ONF), the OEC and BV2 co-culture group modulate microglial cytokines releasing toward the anti-inflammation, and away from the pro-inflammation, which was followed by higher IL-4 and IL-10 and lower TNF-a and IL-6 in their expression levels. In vivo, the transplantation group significantly reduced activated resident microglia/infiltrated macrophage, and expression of pro-inflammatory cytokines in RCS rats retina, increased anti-inflammatory cytokines in transplantation area. Additionally, we found that OECs expressed SOCS3 and down-regulated the JAK2/STAT3 (Janus Kinase 2/Signal Transducer and Activator of Transcription 3) pathway. Thirdly, OEC transplantation reduced Caspase-3 expression, protected inner retinal neurons and photoreceptors and therefore, delayed the visual function degeneration. In conclusion, our data suggest that OECs delay retinal degeneration in RP, at least in part through immunomodulation of microglia via the JAK/STAT pathway.

Emerging role of glycosylation in the polarization of tumor-associated macrophages

Tumors are formed by several cell types interacting in a complex environment of soluble and matrix molecules. The crosstalk between the cells and extracellular components control tumor fate. Macrophages are highly plastic and diverse immune cells that are known to be key regulators of this complex network, which is mostly because they can adjust their metabolism and reprogram their phenotype and effector function. Here, we review the studies that disclose the central role of metabolism and tumor microenvironment in shaping the phenotype and function of macrophages, highlighting the importance of the hexosamine biosynthetic pathway. We further discuss growing evidence of nutrient-sensitive protein modifications such as O-GlcNAcylation and extracellular glycosylation in the function and polarization of tumor-associated macrophages.

Application of CNTF or FGF-2 increases the number of M2-like macrophages after optic nerve injury in adult Rana pipiens

We have previously shown that a single application of the growth factors ciliary neurotrophic factor (CNTF) or fibroblast growth factor 2 (FGF-2) to the crushed optic nerve of the frog, Rana pipiens, increases the numbers and elongation rate of regenerating retinal ganglion cell axons. Here we investigate the effects of these factors on the numbers and types of macrophages that invade the regeneration zone. In control PBS-treated nerves, many macrophages are present 100 μm distal to the crush site at 1 week after injury; their numbers halve by 2 weeks. A single application of CNTF at the time of injury triples the numbers of macrophages at 1 week, with this increase compared to control being maintained at 2 weeks. Application of FGF-2 is equally effective at 1 week, but the macrophage numbers have fallen to control levels at 2 weeks. Immunostaining with a pan-macrophage marker, ED1, and a marker for M2-like macrophages, Arg-1, showed that the proportion of the putative M2 phenotype remained at approximately 80% with all treatments. Electron microscopy of the macrophages at 1 week shows strong phagocytic activity with all treatments, with many vacuoles containing axon fragments and membrane debris. At 2 weeks with PBS or FGF-2 treatment the remaining macrophages are less phagocytically active, containing mainly lipid inclusions. With CNTF treatment, at 2 weeks many of the more numerous macrophages are still phagocytosing axonal debris, although they also contain lipid inclusions. We conclude that the increase in macrophage influx seen after growth factor application is beneficial for the regenerating axons, probably due to more extensive removal of degenerating distal axons, but also perhaps to secretion of growth-promoting substances.

Studies on the Use of Flagellin as an Immunostimulant and Vaccine Adjuvant in Fish Aquaculture

Immunostimulants and vaccines are important for controlling infectious diseases in fish aquaculture. In this study we assess the potential of flagellin to be used for such purposes in rainbow trout (Oncorhynchus mykiss). A recombinant flagellin from the salmonid pathogen Yersinia ruckeri (YRF) has been produced previously by us and shown to be a potent activator of inflammatory cytokines, acute phase proteins and antimicrobial peptides in vitro. Here we show that YRF is the most potent inflammatory activator of three bacterial PAMPs (LPS, peptidoglycan and flagellin) tested. The host response to flagellin was next studied in vivo. The YRF modulated gene expression was examined in two systemic (spleen and liver) and two mucosa-associated (gills and skin) tissues. YRF injection initiated a transient systemic inflammatory response with key pro-inflammatory cytokines (IL-1β, TNFα, IL-6, and IL-11 etc.) and chemokines (CXCL_F4 and CXCL-8) induced rapidly (by 6 h) but subsiding quickly (by 24 h) in multiple tissues. Consequently, a variety of anti-microbial pathways were activated systemically with heightened expression of acute phase proteins, antimicrobial peptides and complement genes in multiple tissues, which was sustained to 24 h in the liver and mucosal tissues. The Th17 cytokine IL-17A/F1 was also induced in the spleen and liver, and Th2 cytokine IL-4/13 was induced in the liver. However, the anti-inflammatory IL-10 and the Th1 cytokine IFNγ were refractory. A secreted form of TLR5 (TLR5s) was induced by flagellin in all tissues examined whilst the membrane form was refractory, suggesting that TLR5s may function as a negative feedback regulator. Trout liver appeared to be an important organ responding to flagellin stimulation, with marked induction of IL-11, IL-23P19, IL-17C1, SAA, and cathelicidin-2. YRF induced a strong antibody response. These antibodies reacted against the middle domain of YRF and were able to decrease YRF bioactivity. Intact YRF was necessary for its bioactivity, as deletion of the N-terminal, C terminal or middle domain of YRF led to functional loss. This study suggests that flagellin could be a potent immunostimulant and vaccine adjuvant for fish aquaculture.

Therapeutic potentials of ginger for treatment of Multiple sclerosis: A review with emphasis on its immunomodulatory, anti-inflammatory and anti-oxidative properties

Multiple sclerosis (MS) is characterized by chronic inflammatory response-induced demyelination of the neurons and degeneration of the axons within the central nervous system (CNS). A complex network of immunopathological-, inflammatory- and oxidative parameters involve in the development and advancement of MS. The anti-inflammatory, immunomodulatory and anti-oxidative characteristics of the ginger and several of its components have been indicated in some of experimental and clinical investigations. The possible therapeutic potentials of ginger and its ingredients in the treatment of MS may exert mainly through the regulation of the Th1-, Th2-, Th9-, Th17-, Th22- and Treg cell-related immune responses, down-regulation of the B cell-related immune responses, modulation of the macrophages-related responses, modulation of the production of pro- and anti-inflammatory cytokines, down-regulation of the arachidonic acid-derived mediators, interfering with the toll like receptor-related signaling pathways, suppression of the inflammasomes, down-regulation of the oxidative stress, reduction of the adhesion molecules expression, and down-regulation of the expression of the chemokines and chemokine receptors. This review aimed to provide a comprehensive knowledge regarding the immunomodulatory-, anti-inflammatory and anti-oxidative properties of ginger and its components, and highlight novel insights into the possible therapeutic potentials of this plant for treatment of MS. The review encourages more investigations to consider the therapeutic potentials of ginger and its effective components for managing of MS.

Differential expression of TLRs 2, 4, 9, iNOS and TNF-α and arginase activity in peripheral blood monocytes from glucantime unresponsive and responsive patients with anthroponotic cutaneous leishmaniasis caused by Leishmania tropica

BACKGROUND

Detection of the mechanism of host/parasite interactions in unresponsive forms of anthroponotic cutaneous leishmaniasis (ACL) caused by Leishmania tropica is helpful for immunotherapy and vaccine development. In the present study, the gene expression of toll-like receptors (TLRs), TNF-α, iNOS and also arginase (ARG) activity in monocytes from Glucantime unresponsive in comparison to responsive patients infected with L. tropica was investigated.

METHODS

In this case-control study, patients with unresponsive (n = 10) and responsive (n = 10) ACL were recruited. Gene expression of TLR2, TLR4, TLR9, TNF-α and iNOS was analyzed in L. tropica-exposed monocytes. The level of ARG activity in both isolated promastigotes and the lysates of monocytes was also determined.

RESULTS

L. tropica-exposed monocytes represented higher expression of all three TLRs and TNF-α and lower expression of iNOS compared to unexposed ones in both groups of patients. Results revealed a significant down-regulation of TLR2 and TNF-α and up-regulation of TLR9 expression in unresponsive isolates in comparison to responsive ones. Besides, ARG level showed a significant increase in L. tropica-stimulated monocytes and cultured promastigotes from unresponsive isolates versus responsive ones.

CONCLUSIONS

The decreased TLR2, TLR4, TNF-α and iNOS and the increased level of TLR9 expression in L. tropica-exposed monocytes from unresponsive isolates and also the increment in ARG activity in their promastigotes and monocytes, might possibly be involved in the severity of the disease and leading to Glucantime unresponsiveness.

Gold nanoparticles attenuates bacterial sepsis in cecal ligation and puncture mouse model through the induction of M2 macrophage polarization

BACKGROUND

Gold nanoparticles (AuNP) have several biochemical advantageous properties especially for a candidate of drug carrier. However, the non-conjugated AuNP has a higher rate of cellular uptake than the conjugated ones. Spherical AuNP in a proper size (20-30 nm) is non-toxic to mice and shows anti-inflammatory properties. We tested if the administration of AuNP, as an adjuvant to antibiotics, could attenuate bacterial sepsis in cecal ligation and puncture (CLP) mouse model with antibiotic (imipenem/cilastatin).

RESULTS

Indeed, AuNP administration at the time of CLP improved the survival, blood bacterial burdens, kidney function, liver injury and inflammatory cytokines (TNF-α, IL-6, IL-1β and IL-10). AuNP also decreased M1 macrophages (CD86 + ve in F4/80 + ve cells) and increased M2 macrophages (CD206 + ve in F4/80 + ve cells) in the spleens of sepsis mice. The weak antibiotic effect of AuNP was demonstrated as the reduction of E. coli colony after 4 h incubation. In addition, AuNP altered cytokine production of bone-marrow-derived macrophages including reduced TNF-α, IL-6 and IL-1β but increased IL-10 at 6 and 24 h. Moreover, AuNP induced macrophage polarization toward anti-inflammatory responses (M2) as presented by increased Arg1 (Arginase 1) and PPARγ with decreased Nos2 (inducible nitric oxide synthase, iNos) and Nur77 at 3 h after incubation in vitro.

CONCLUSIONS

The adjuvant therapy of AuNP, with a proper antibiotic, attenuated CLP-induced bacterial sepsis in mice, at least in part, through the antibiotic effect and the induction of macrophage function toward the anti-inflammatory responses.

Galectin 3 expression in regional lymph nodes and lymph node metastases of oral squamous cell carcinomas

BACKGROUND

Neck dissection is standard in surgical management of oral squamous cell carcinomas (oscc). However, the immunologic link between primary tumor and lymph nodes is insufficiently understood. Galectin 3 (Gal3) promotes M2 polarization of macrophages and contributes to immunosuppression. The current study analyzes the association between Gal3 expression in regional lymph nodes of oscc with histomorphologic parameters (T-, N-, L- Pn-stage, grading) of the primary tumor. Additionally, Gal3 expression is correlated with markers of macrophage polarization (M1 vs. M2).

METHODS

Preoperative diagnostic biopsies (n = 26), tumor resection specimens (n = 34), tumor-free lymph nodes (n = 28) and lymph node metastases (n = 10) of T1/T2 oscc patients were immunohistochemically analyzed for Gal3 and macrophage marker (CD68, CD11c, CD163 and MRC1) expression. The number of positive cells and the expression ratios were quantitatively assessed.

RESULTS

High Gal3 expression in tumor-free regional lymph nodes was significantly (p < 0.05) associated with increased tumor size. The epithelial compartment of lymph node metastases showed a significantly (p < 0.05) increased Gal3 expression compared to biopsies and tumor resection specimens. Cell density of M2 macrophages was significantly (p < 0.05) and positively correlated with the number of Gal3 expressing cells in lymph nodes and tumor specimens.

CONCLUSION

Gal3 expression in regional lymph nodes might be associated with oscc progression. The increased Gal3 expression in regional lymph nodes of larger tumors underlines the need of immunomodulatory treatment concepts in early-stage oscc. Blocking of Gal3 might be a therapeutic option in oral cancer.

Studies on the effects of LPS, ß-glucan and metabolic inhibitors on the respiratory burst and gene expression in Atlantic salmon macrophages

Reactive oxygen species (ROS) production in macrophage-like cells is induced as an antimicrobial defence against invading pathogens. In this study, we have explored how different stimuli and metabolic inhibitors affect the level of respiratory burst in Atlantic salmon (Salmo salar L.) head kidney macrophage-like cells. Cells stimulated in vitro by bacterial lipopolysaccharide (LPS) and ß-glucan showed increased production of ROS compared to unstimulated cells. Both stimulation and costimulation by curdlan (ß-glucan) induced a higher production of ROS compared to stimulation and costimulation by LPS. Metabolic inhibitors co-incubated with the stimulants did not, in most cases, perturb the level of ROS generation in the salmon macrophage-like cells. The NAD⁺ content as well as the NAD⁺ /NADH ratio increased in curdlan and LPS + curdlan-stimulated cells compared to control cells, which indicated increased metabolic activity in the stimulated cells. Supporting these findings, gene analysis using real-time quantitative PCR showed that arginase-1 and IL-1ß genes were highly expressed in the stimulated cells.

Chronic liver injury promotes hepatocarcinoma cell seeding and growth, associated with infiltration by macrophages

Ninety percent of hepatocarcinoma (HCC) develops in a chronically damaged liver. Interactions between non‐tumor stromal components, especially macrophages, and cancer cells are still incompletely understood. Our aim was to determine whether a chronically injured liver represents a favorable environment for the seeding and growth of HCC cells, and to evaluate the potential roles of macrophages infiltrated within the tumor. HCC cells were injected into the liver in healthy mice (healthy liver group [HL]) and in mice chronically treated with carbon tetrachloride (CCl₄) for 7 weeks (CCl₄ 7w group). Livers were examined for the presence of tumor 2 weeks post‐injection. Tumor and non‐tumor tissues were analyzed for macrophage infiltration, origin (monocytes‐derived vs resident macrophages) and polarization state, and MMP production. Fifty‐three percent of mice developed neoplastic lesion in the HL group whereas a tumor lesion was found in all livers in the CCl₄ 7w group. Macrophages infiltrated more deeply the tumors of the CCl₄ 7w group. Evaluation of factors involved in the recruitment of macrophages and of markers of their polarization state was in favor of prominent infiltration of M2 pro‐tumor monocyte‐derived macrophages inside the tumors developing in a chronically injured liver. MMP‐2 and ‐9 production, attributed to M2 pro‐tumor macrophages, was significantly higher in the tumors of the CCl₄ 7w group. In our model, chronic liver damage promotes cancer development. Our results suggest that an injured background favors the infiltration of M2 pro‐tumor monocyte‐derived macrophages. These secrete MMP‐2 and MMP‐9 that promote tumor progression.

Partial Depletion of Peripheral M1 Macrophages Reverses Motor Deficits in MPTP-Treated Mouse by Suppressing Neuroinflammation and Dopaminergic Neurodegeneration

Background: Neuroinflammation plays an important role in the pathogenesis of Parkinson's disease (PD). Inflammatory cytokines in the peripheral immune system can induce neuroinflammation in central nervous system (CNS). Whether the peripheral immune system is involved in PD is unclear. The present study investigated the contribution of the peripheral immune system to the neuronal loss in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine(MPTP) model of PD.

Methods: MPTP was intraperitoneally injected into mice to generate a PD model. Mice received clodronate liposomes every 3 days to deplete peripheral macrophages. The percentages of macrophages were measured by flow cytometry at 1, 3, and 7 days after MPTP injection. Neurobehavioral parameters, protein expression, inflammatory cytokines release, and microglia activation were measured by the open field test, western blotting, quantitative polymerase chain reaction (qPCR), and immunofluorescence staining, respectively at 7 days after MPTP injection.

Results: Our study revealed that intraperitoneal injection of MPTP could increase peripheral M1 macrophages levels. It also can induce T cells infiltration and cytokine release. Depletion of M1 macrophages by clodronate liposomes suppressed these inflammatory effects and blunted the loss of TH+ nigral neurons and functional impairments caused by MPTP.

Conclusion: Our results indicated the critical role of M1 macrophages in the pathogenesis of PD and proposed inhibition of M1 macrophages as a promising therapeutic approach for neurodegeneration.

Transcriptional Regulation of Macrophages Polarization by MicroRNAs

Diversity and plasticity are the hallmarks of cells from the monocyte-macrophage lineage. Macrophages undergo classical M1 or alternative M2 activation in response to the microenvironment signals. Several transcription factors, such as peroxisome proliferator-activated receptors, signal transducers and activators of transcription, CCAAT-enhancer-binding proteins, interferon regulatory factors, Kruppel-like factors, GATA binding protein 3, nuclear transcription factor-κB, and c-MYC, were found to promote the expression of specific genes, which dictate the functional polarization of macrophages. Importantly, these transcription factors can be regulated by microRNAs (miRNAs), a group of small non-coding RNAs, which regulate gene expression through translation repression or mRNA degradation. Recent studies have also revealed that miRNAs control macrophage polarization by regulating transcription factors in response to the microenvironment signals. This review will summarize recent progress of miRNAs in the transcriptional regulation of macrophage polarization and provide the insights into the development of macrophage-centered diagnostic and therapeutic strategies.

ER-localized protein-Herpud1 is a new mediator of IL-4-induced macrophage polarization and migration

ER-localized proteins have been reported function in endoplasmic reticulum, unfolded protein degradation and destruction of misfolded proteins by the ER-associated protein degradation (ERAD) system, but their function in the chemotaxis of macrophage cells remained un-addressed. Here, we showed that ER protein with ubiquitin like domain 1(Herpud1) was upregulated in IL-4-treated M2 macrophage cells and its expression pattern was similar with macrophage polarization markers, such as Arg1, Mrc1 and Fizz1. Inhibition of Herpud1 by using specific target shRNA decreased these marker's expression at mRNA and protein level in IL-4-treated or -untreated M2 macrophage cells. IL-4 treatment promoted M2 macrophage cell migration and polarization, but this promotion was weakened by Herpud1 depletion and we got similar results by inhibition of ER stress response with chemical molecule 4-phenylbutyric acid (4-PBA) in IL-4-treated or untreated-M2 macrophage cells with Herpud1 overexpression. These results indicated that depending on ER-associated protein degradation (ERAD) to help unfolded protein degradation or destruction is not the only function of Herpud1 and acting as a mediator of IL-4 induced macrophage activation and polarization maybe another unrevealed function, elucidating the role of Herpud1-associated M2 macrophage cell polarization and activation are helpful for exploration the function of macrophage cells in immune response.

Fibrocytes: A Novel Stromal Cells to Regulate Resistance to Anti-Angiogenic Therapy and Cancer Progression

An adequate blood supply is essential for cancer cells to survive and grow; thus, the concept of inhibiting tumor angiogenesis has been applied to cancer therapy, and several drugs are already in clinical use. It has been shown that treatment with those anti-angiogenic drugs improved the response rate and prolonged the survival of patients with various types of cancer; however, it is also true that the effect was mostly limited. Currently, the disappointing clinical results are explained by the existence of intrinsic or acquired resistance to the therapy mediated by both tumor cells and stromal cells. This article reviews the mechanisms of resistance mediated by stromal cells such as endothelial cells, pericytes, fibroblasts and myeloid cells, with an emphasis on fibrocytes, which were recently identified as the cell type responsible for regulating acquired resistance to anti-angiogenic therapy. In addition, the other emerging role of fibrocytes as mediator-producing cells in tumor progression is discussed.

Leprosy As a Complex Infection: Breakdown of the Th1 and Th2 Immune Paradigm in the Immunopathogenesis of the Disease

Leprosy is a chronic infectious disease whose evolution involves complex immune mechanisms of the host that influence the clinical presentation of the disease. For many years, the main interpretation of the host defense response was based on characterization of the established immune paradigm between T helper (Th) 1 and Th2 lymphocytes. However, with advances in the knowledge of immunology, new approaches have emerged along with the development of new immunological pathways that have changed the interpretation of the long-established paradigm of the polar forms of the disease, especially with the identification of new subtypes of T lymphocytes such as Th9, Th17, Th22, and Tregs. Thus, this review discusses the role of these new subtypes of T helper lymphocytes and how the development of the immune response of these cells modifies the pattern of the Th1/Th2 response in the immunopathogenesis of leprosy.