CD14 influences host immune responses and alternative activation of macrophages during Schistosoma mansoni infection

The anti-infective and immunologic effect of babassu (Attalea speciosa, Mart. ex Spreng) reduces mortality induced by MRSA-Staphylococcus aureus

ETHNOPHARMACOLOGICAL RELEVANCE

Babassu mesocarp, derived from the Attalea speciosa fruits, is used in folk medicine for infections, inflammatory diseases, and skin wounds.

AIM OF THE STUDY

To investigate the antimicrobial and immunological effect of babassu mesocarp aqueous extract (BAE) in Swiss mice lethally infected with methicillin-resistant Staphylococcus aureus (MRSA).

MATERIALS AND METHODS

The animals (n = 14/group) received an overload of MRSA (3.0 × 108 CFU/mL, via intraperitoneal) and were treated 6 h later with the BAE (125 and 250 mg/kg, subcutaneously). Two experiments were performed with four groups each (Control, ATB, BAE125 and BAE 250). The first was to determine the survival (n = 7 animals/group). The second is to evaluate 24h after infection the number of Colony Forming Units (CFU) and cells in the blood, peritoneum and bronchoalveolar fluid. Cytometric Bead Assay - CBA quantified the cytokines and flow cytometry to determine the cellular distribution in the mesenteric lymph node.

RESULTS

Treatment with BAE improved the survival (60%) in all groups, reduced the number of colony-forming units in the peritoneum and blood, the number of peritoneal and bronchoalveolar cells, and the levels of pro-inflammatory IL-6, TNF-α, and IL-17 cytokines. Additionally, BAE increased: IL-10 and INF-γ levels, nitric oxide release, CD4+ T helper cells, CD14+/IaIe + activated macrophages and Ly6G + neutrophils in the mesenteric lymph node.

CONCLUSIONS

BAE can be used as a complementary treatment during infections due to its antimicrobial and immunomodulatory effect and the ability to protect animals from death after MRSA lethal infection.

The interaction of Schistosoma mansoni infection with diabetes mellitus and obesity in mice

Human schistosomiasis is one of the most prevalent parasitic diseases worldwide. Various host factors can affect the host-parasite interactions. Therefore, the aim of the present work was to determine the parasitological, histopathological, biochemical, and immunological status of Schistosoma mansoni-infected hosts with metabolic disorders to identify the underlying possible mechanisms of these comorbidities. The study animals were divided into four groups. Group I represented the control groups, namely, the normal control group, the S. mansoni-infected control group, and the noninfected type 1 diabetes (T1DM), type 2 diabetes (T2DM), and obesity groups. The mice of the other three groups underwent induction of T1DM (Group II), T2DM (Group III) and obesity (Group IV) before being infected with S. mansoni. All mice were subjected to body weight measurement, blood glucose and insulin assessment, parasitological evaluation of adult worm count, tissue egg count and intestinal oogram. Histopathological and immunohistochemical study using anti-glial fibrillary acidic protein (GFAP) in hepatic stellate cells (HSCs) and image analysis of Masson's trichrome-stained liver sections using ImageJ (Fiji) software were carried out. Additionally, immunological analysis of tumour necrosis factor (TNF) beta, interleukin-5 (IL-5), IL-10, Forkhead box P3 (FOXP3) and pentraxin 3 (PTX3) levels besides biochemical study of total lipid profile were evaluated. The present study revealed a significant increase in the adult worm count and tissue egg output in the obesity group compared to the infected control group. The oogram of counted eggs showed prevalence of immature eggs in T1DM group, while T2DM and obese groups showed prevalence of mature eggs. The fibrosis area percentage showed significant increase in T2DM and obese groups while it was decreased in T1DM group in comparison to infected control group. Our data also showed significant increase in the levels of TNF-β, IL-5, PTX3 in T1DM, T2DM and obesity groups in comparison to infected control group, whilst the levels of FOXP3 and IL-10 were increased in the infected groups in comparison to their noninfected controls. Moreover, infected T1DM, T2DM and obesity groups showed higher blood glucose and lipid profile in comparison to the infected control group. However, these parameters were improved in comparison to their noninfected controls. In sum, induction of T2DM and obesity increased tissue egg counts, mature egg percentage, and fibrosis density, while schistosome infection induced changes in the lipid profile and blood glucose levels in infected diabetic and obese groups and impacted favorably insulin levels in obese mice. By better understanding the complexities of host-parasite interactions, efforts to reduce the burden of these debilitating diseases can be improved.

Immunological mechanisms involved in macrophage activation and polarization in schistosomiasis

Human schistosomiasis is caused by helminths of the genus Schistosoma. Macrophages play a crucial role in the immune regulation of this disease. These cells acquire different phenotypes depending on the type of stimulus they receive. M1 macrophages can be ‘classically activated’ and can display a proinflammatory phenotype. M2 or ‘alternatively activated’ macrophages are considered anti-inflammatory cells. Despite the relevance of macrophages in controlling infections, the role of the functional types of these cells in schistosomiasis is unclear. This review highlights different molecules and/or macrophage activation and polarization pathways during Schistosoma mansoni and Schistosoma japonicum infection. This review is based on original and review articles obtained through searches in major databases, including Scopus, Google Scholar, ACS, PubMed, Wiley, Scielo, Web of Science, LILACS and ScienceDirect. Our findings emphasize the importance of S. mansoni and S. japonicum antigens in macrophage polarization, as they exert immunomodulatory effects in different stages of the disease and are therefore important as therapeutic targets for schistosomiasis and in vaccine development. A combination of different antigens can provide greater protection, as it possibly stimulates an adequate immune response for an M1 or M2 profile and leads to host resistance; however, this warrants in vitro and in vivo studies.

In silico identification of novel biomarkers for key players in transition from normal colon tissue to adenomatous polyps

Adenomatous polyps of the colon are the most common neoplastic polyps. Although most of adenomatous polyps do not show malign transformation, majority of colorectal carcinomas originate from neoplastic polyps. Therefore, understanding of this transformation process would help in both preventive therapies and evaluation of malignancy risks. This study uncovers alterations in gene expressions as potential biomarkers that are revealed by integration of several network-based approaches. In silico analysis performed on a unified microarray cohort, which is covering 150 normal colon and adenomatous polyp samples. Significant gene modules were obtained by a weighted gene co-expression network analysis. Gene modules with similar profiles were mapped to a colon tissue specific functional interaction network. Several clustering algorithms run on the colon-specific network and the most significant sub-modules between the clusters were identified. The biomarkers were selected by filtering differentially expressed genes which also involve in significant biological processes and pathways. Biomarkers were also validated on two independent datasets based on their differential gene expressions. To the best of our knowledge, such a cascaded network analysis pipeline was implemented for the first time on a large collection of normal colon and polyp samples. We identified significant increases in TLR4 and MSX1 expressions as well as decrease in chemokine profiles with mostly pro-tumoral activities. These biomarkers might appear as both preventive targets and biomarkers for risk evaluation. As a result, this research proposes novel molecular markers that might be alternative to endoscopic approaches for diagnosis of adenomatous polyps.

Ovine CD14- an Immune Response Gene Has a Role Against Gastrointestinal Nematode Haemonchus contortus-A Novel Report

CD14 (also known as the monocyte differentiation antigen) is an important immune response gene known to be primarily responsible for innate immunity against bacterial pathogens, and as a pattern recognition receptor (PRR), binds with LPS (endotoxin), lipoproteins, and lipotechoic acid of bacteria. So far very limited work has been conducted in parasitic immunology. In the current study, we reported the role of CD14 in parasitic immunology in livestock species (sheep) for the first time. Ovine CD14 is characterized as a horse-shoe shaped bent solenoid with a hydrophobic amino-terminal pocket for CD14 along with domains. High mutation frequency was observed, out of total 41 mutations identified, 23 mutations were observed to be thermodynamically unstable and 11 mutations were deleterious in nature, causing major functional alteration of important domains of CD14, an indication of variations in individual susceptibility for sheep against Haemonchus contortus infestations. In silico studies with molecular docking reveal a role of immune response against Haemonchus contortus in sheep, which is later confirmed with experimental evidence through differential mRNA expression analysis for sheep, which revealed better expression of CD14 in Haemonchus contortus infected sheep compared to that of non-infected sheep. We confirmed the above findings with supportive evidence through haematological and biochemical analyses. Phylogenetic analysis was conducted to assess the evolutionary relationship with respect to humans and it was observed that sheep may well be used as model organisms due to better genetic closeness compared to that of mice.

Remodeling tumor microenvironment with nanomedicines

The tumor microenvironment (TME) has been recognized as a major contributor to cancer malignancy and therapeutic resistance. Thus, strategies directed to re-engineer the TME are emerging as promising approaches for improving the efficacy of antitumor therapies by enhancing tumor perfusion and drug delivery, as well as alleviating the immunosuppressive TME. In this regard, nanomedicine has shown great potential for developing effective treatments capable of re-modeling the TME by controlling drug action in a spatiotemporal manner and allowing long-lasting modulatory effects on the TME. Herein, we review recent progress on TME re-engineering by using nanomedicine, particularly focusing on formulations controlling TME characteristics through targeted interaction with cellular components of the TME. Importantly, the TME should be re-engineering to a quiescent phenotype rather than be destroyed. Finally, immediate challenges and future perspectives of TME-re-engineering nanomedicines are discussed, anticipating further innovation in this growing field. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease.

Dexamethasone Promotes Aspergillus fumigatus Growth in Macrophages by Triggering M2 Repolarization via Targeting PKM2

Since long-term corticosteroid treatment is associated with emerging opportunistic fungal infections causing high morbidity and mortality in immune-suppressed individuals, here we characterized the impact of dexamethasone (Dex) treatment on Aspergillus fumigatus-related immune modulation. We found by high content screening and flow cytometric analyses that during monocyte-to-macrophage differentiation, as little as 0.1 µg/mL Dex resulted in a shift in macrophage polarization from M1 to M2-like macrophages. This macrophage repolarization mediated via Dex was characterized by significant upregulation of the M2 marker CD163 and downmodulation of M1 markers CD40 and CD86 as well as changes in phenotypic properties and adherence. These Dex-mediated phenotypic alterations were furthermore associated with a metabolic switch in macrophages orchestrated via PKM2. Such treated macrophages lost their ability to prevent Aspergillus fumigatus germination, which was correlated with accelerated fungal growth, destruction of macrophages, and induction of an anti-inflammatory cytokine profile. Taken together, repolarization of macrophages following corticosteroid treatment and concomitant switch to an anti-inflammatory phenotype might play a prominent role in triggering invasive aspergillosis (IA) due to suppression of innate immunological responses necessary to combat extensive fungal outgrowth.

Monoclonal Antibodies Generated against Glycoconjugates Recognize Chemical Linkers

Monoclonal antibodies (mAbs) that recognize glycans are useful tools to assess carbohydrates’ structure and function. We sought to produce IgG mAbs to the human milk oligosaccharide (HMO), lacto-N-fucopentaose III (LNFPIII). LNFPIII contains the Lewis^x antigen, which is found on the surface of schistosome parasites. mAbs binding the Lewis^x antigen are well-reported in the literature, but mAbs recognizing HMO structures are rare. To generate mAbs, mice were immunized with LNFPIII-DEX (P3DEX) plus CpGs in VacSIM^®, a novel vaccine/drug delivery platform. Mice were boosted with LNFPIII-HSA (P3HSA) plus CpGs in Incomplete Freund’s Adjuvant (IFA). Splenocytes from immunized mice were used to generate hybridomas and were screened against LNFPIII conjugates via enzyme-linked immunosorbent assay (ELISA). Three positive hybridomas were expanded, and one hybridoma, producing IgG and IgM antibodies, was cloned via flow cytometry. Clone F1P2H4D8D5 was selected because it produced IgG1 mAbs, but rescreening unexpectedly showed binding to both LNFPIII and lacto-N-neotetraose (LNnT) conjugates. To further assess the specificity of the mAb, we screened it on two glycan microarrays and found no significant binding. This finding suggests that the mAb binds to the acetylphenylenediamine (APD) linker-spacer structure of the conjugate. We present the results herein, suggesting that our new mAb could be a useful probe for conjugates using similar linker spacer structures.

Purification of protein therapeutics via high-affinity supramolecular host-guest interactions

Efficient purification is crucial to providing large quantities of recombinant therapeutic proteins, such as monoclonal antibodies and cytokines. However, affinity techniques for manufacturing protein therapeutics that use biomolecule-conjugated agarose beads that harness specific biomolecular interactions suffer from issues related to protein denaturation, contamination and the need to maintain biomolecule-specific conditions for efficient protein capture. Here, we report a versatile and scalable method for the purification of recombinant protein therapeutics. The method exploits the high-affinity and controllable host-guest interactions between cucurbit[7]uril (CB[7]) and selected guests such as adamantylammonium. We show that the Herceptin (the brand name of trastuzumab, a monoclonal antibody drug used to treat breast cancer) and the much smaller cytokine interferon α-2a can be purified by site-specifically tagging them with adamantylammonium using the enzyme sortase A, followed by high-affinity binding with CB[7]-conjugated agarose beads and the recovery of the protein using a guest with a stronger affinity for CB[7]. The thermal and chemical stability of CB[7] beads and their scalability, recyclability and low cost may also make them advantageous for the manufacturing of biosimilars.

Interactions between macrophages and helminths

Macrophages, the major population of tissue-resident mononuclear phagocytes, contribute significantly to the immune response during helminth infection. Alternatively activated macrophages (AAM) are induced early in the anti-helminth response following tissue insult and parasite recognition, amplifying the early type 2 immune cascade initiated by epithelial cells and ILC2s, and subsequently driving parasite expulsion. AAM also contribute to functional alterations in tissues infiltrated with helminth larvae, mediating both tissue repair and inflammation. Their activation is amplified and occurs more rapidly following reinfection, where they can play a dual role in trapping tissue migratory larvae and preventing or resolving the associated inflammation and damage. In this review, we will address both the known and emerging roles of tissue macrophages during helminth infection, in addition to considering both outstanding research questions and new therapeutic strategies.

Metabolic Programming of Macrophages: Implications in the Pathogenesis of Granulomatous Disease

Metabolic reprogramming is rapidly gaining appreciation in the etiology of immune cell dysfunction in a variety of diseases. Tuberculosis, schistosomiasis, and sarcoidosis represent an important class of diseases characterized by the formation of granulomas, where macrophages are causatively implicated in disease pathogenesis. Recent studies support the incidence of macrophage metabolic reprogramming in granulomas of both infectious and non-infectious origin. These publications identify the mechanistic target of rapamycin (mTOR), as well as the major regulators of lipid metabolism and cellular energy balance, peroxisome proliferator receptor gamma (PPAR-γ) and adenosine monophosphate-activated protein kinase (AMPK), respectively, as key players in the pathological progression of granulomas. In this review, we present a comprehensive breakdown of emerging research on the link between macrophage cell metabolism and granulomas of different etiology, and how parallels can be drawn between different forms of granulomatous disease. In particular, we discuss the role of PPAR-γ signaling and lipid metabolism, which are currently the best-represented metabolic pathways in this context, and we highlight dysregulated lipid metabolism as a common denominator in granulomatous disease progression. This review therefore aims to highlight metabolic mechanisms of granuloma immune cell fate and open up research questions for the identification of potential therapeutic targets in the future.

Macrophage CD14 impacts immune defenses against influenza virus in allergic hosts

Asthma and influenza are leading causes of worldwide morbidity and mortality. Although these two conditions can co-exist in the same patient, the immune parameters that impact disease outcomes are not fully elucidated. The importance of macrophages to both conditions suggested a role for CD14, a co-receptor for endotoxin, as a regulatory mechanism for innate immune responses during asthma and influenza co-morbidity. Herein, we hypothesized that parameters of influenza morbidity will be reduced in the absence of CD14. Age and gender matched wild-type (WT) and CD14 knock-out (KO) mice were subjected to our validated model of Aspergillus-induced model of asthma and/or influenza. Characteristics of disease pathogenesis were investigated using standard methods in weight loss, flow cytometry, airway resistance, histology, quantitative real-time PCR, and viral titer quantification. The absence of CD14 did not have an impact on morbidity as these mice were equally susceptible to disease with similar airway resistance. Peribronchovascular inflammation and goblet cell content were equivalent between WT and KO mice in asthma alone and asthma and influenza co-morbidity. Co-morbid KO mice had less lymphocytes and eosinophils in the airways although their lung viral burden was equivalent to WT. Inflammatory gene signatures were altered in co-morbid mice in each genotype. CD14 expression on macrophages is necessary for airway inflammation but not for viral pathogenesis in allergic hosts.

Study of peritoneal macrophage immunophenotype in sheep experimentally infected with Fasciola hepatica

During Fasciola hepatica infection, the parasite has the capability to modulate the host immune response towards a non-protector Th2 type instead of Th1. This type of immune response is closely related to the alternative activation of macrophages (M2 profile) as has been shown in vivo in murine models. In this study, an experiment was carried out in order to evaluate the expression of CD68, CD14, CD206 and iNOS in cells present in the peritoneal fluid of sheep during early stages of infection with F. hepatica (1, 3, 9 and 18 days post-infection, dpi) by immunocytochemistry. To the authors' knowledge, this is the first report that studies the in vivo immunophenotype of macrophages from the peritoneal fluid of sheep infected with F. hepatica. Throughout the experiments the absolute number of leucocytes progressively increased, reaching its highest value at 18 dpi, mainly due to the increase of eosinophils. This immunocytochemical study had two purposes: 1) CD68 expression was assessed with Hansel counterstaining, to optimally identify peritoneal macrophages, eosinophils and lymphocytes; 2) expression of CD14, CD206 and iNOS was evaluated to identify alternative or classical pathways of macrophage activation. The results showed a significant increase in CD14 from day 3 dpi compared with the non-infected group. CD206 expression at all time-points showed a significant and dramatic increase in comparison with the uninfected group. On the other hand, iNOS expression showed little variation, and was significantly decreased at 18 dpi in comparison with the uninfected group. These results suggest that F. hepatica induces an alternative activation of peritoneal macrophages of sheep from the first day post-infection, which may facilitate parasite survival. This is the first report describing M2 activation of peritoneal macrophages in ruminants infected with F. hepatica.

Variations in CD14 Gene Are Associated With Autoimmune Thyroid Diseases in the Chinese Population

Autoimmune thyroid diseases (AITDs) are chronic organ-specific autoimmune diseases and mainly include Graves' disease (GD) and Hashimoto's thyroiditis (HT). CD14 is an important component of the immune system as a receptor for gram-negative lipopolysaccharide (LPS). The genetic polymorphisms of CD14 have been confirmed to be associated with a variety of autoimmune diseases. However, its relationship with AITDs is still unclear. The study was aimed to determine whether four single nucleotide polymorphisms (rs2915863, rs2569190, rs2569192, and rs2563298) of CD14 are associated with AITDs and its subgroups of GD and HT. The results showed significant association of rs2915863 and rs2569190 with GD. The frequencies of rs2915863 genotypes and T allele in patients with GD differed significantly from their controls (P = 0.007 and P = 0.021, respectively). For rs2569190, frequencies of genotypes and G allele in GD patients also showed positive P-values (P = 0.038 and P = 0.027, respectively). The correlations between these two loci and GD are more pronounced in female GD patients and patients with a family history. In genetic model analysis, the allele model, recessive model, and homozygous model of rs2569190 and rs2915863 embodied strong correlations with GD after the adjusting of age and gender (P = 0.014, P = 0.015, P = 0.009, and P = 0.014, P = 0.001, P = 0.006, respectively). However, these four sites are not related to HT. We firstly discovered the relationship between CD14 gene polymorphism and GD, and the results indicate that CD14 is an important risk locus for AITD and its SNPs may contribute to host's genetic predisposition to GD.

High-dose PMA with RANKL and MCSF induces THP‑1 cell differentiation into human functional osteoclasts in vitro

Osteoclasts are large multinuclear cells, which serve role in erosive bone disease. However, it is not possible to separate osteoclasts from cortical bone in order to culture the cells for further experiments. Therefore, a human osteoclast model is required to investigate the underlying mechanism of bone destruction. The most commonly‑used osteoclast model is the RAW264.7 cell line, a murine mononuclear macrophage cell line; however, there exists no reliable osteoclast model using a human cell line. The aim of the present study was to establish a functional osteoclast model using the THP‑1 cell line. Suspended THP‑1 cells were stimulated for 2 days with 5 or 100 ng/ml phorbol‑12 myristate‑13 acetate (PMA) in order to induce the cells to differentiate into adherent macrophages. A 10‑day stimulation with 50 ng/ml receptor activator of nuclear factor κ‑B ligand (RANKL) and macrophage colony‑stimulating factor (MCSF) was performed in order to induce macrophage differentiation into osteoclasts. Treatment with high‑dose PMA with RANKL and MCSF enabled the THP‑1 cells to form tartrate‑resistant acid phosphatase‑positive osteoclasts, which were able absorb bone in a bone resorption test. Treatment with low‑dose PMA with RANKL and MCSF failed to induce THP‑1 cell differentiation into osteoclasts. PMA alone, or a combination of RANKL and MCSF alone, is insufficient to stimulate THP‑1 cell differentiation into osteoclasts. In the present study, a reliable human osteoclast model was established using the THP‑1 cell line. This osteoclast model may provide a useful tool for further studies.

Macrophage Polarization

Macrophage polarization refers to how macrophages have been activated at a given point in space and time. Polarization is not fixed, as macrophages are sufficiently plastic to integrate multiple signals, such as those from microbes, damaged tissues, and the normal tissue environment. Three broad pathways control polarization: epigenetic and cell survival pathways that prolong or shorten macrophage development and viability, the tissue microenvironment, and extrinsic factors, such as microbial products and cytokines released in inflammation. A plethora of advances have provided a framework for rationally purifying, describing, and manipulating macrophage polarization. Here, I assess the current state of knowledge about macrophage polarization and enumerate the major questions about how activated macrophages regulate the physiology of normal and damaged tissues.

Role of Macrophages in the Repair Process during the Tissue Migrating and Resident Helminth Infections

The Th1/Th2/Th17 balance is a fundamental feature in the regulation of the inflammatory microenvironment during helminth infections, and an imbalance in this paradigm greatly contributes to inflammatory disorders. In some cases of helminthiasis, an initial Th1 response could occur during the early phases of infection (acute), followed by a Th2 response that prevails in chronic infections. During the late phase of infection, alternatively activated macrophages (AAMs) are important to counteract the inflammation caused by the Th1/Th17 response and larval migration, limiting damage and repairing the tissue affected. Macrophages are the archetype of phagocytic cells, with the primary role of pathogen destruction and antigen presentation. Nevertheless, other subtypes of macrophages have been described with important roles in tissue repair and immune regulation. These types of macrophages challenge the classical view of macrophages activated by an inflammatory response. The role of these subtypes of macrophages during helminthiasis is a controversial topic in immunoparasitology. Here, we analyze some of the studies regarding the role of AAMs in tissue repair during the tissue migration of helminths.

Molecular and epigenetic basis of macrophage polarized activation

Macrophages are unique cells for origin, heterogeneity and plasticity. At steady state most of macrophages are derived from fetal sources and maintained in adulthood through self-renewing. Despite sharing common progenitors, a remarkable heterogeneity characterized tissue-resident macrophages indicating that local signals educate them to express organ-specific functions. Macrophages are extremely plastic: chromatin landscape and transcriptional programs can be dynamically re-shaped in response to microenvironmental changes. Owing to their ductility, macrophages are crucial orchestrators of both initiation and resolution of immune responses and key supporters of tissue development and functions in homeostatic and pathological conditions. Herein, we describe current understanding of heterogeneity and plasticity of macrophages using the M1-M2 dichotomy as operationally useful simplification of polarized activation. We focused on the complex network of signaling cascades, metabolic pathways, transcription factors, and epigenetic changes that control macrophage activation. In particular, this network was addressed in sepsis, as a paradigm of a pathological condition determining dynamic macrophage reprogramming.

An agonist antibody that blocks autoimmunity by inducing anti-inflammatory macrophages

We have devised a method of using intracellular combinatorial libraries to select antibodies that control cell fates. Many agonist antibodies have been selected with this method, and the process appears to be limited only by the availability of a phenotypic selection system. We demonstrate the utility of this approach to discover agonist antibodies that engage an unanticipated target and regulate macrophage polarization by selective induction of anti-inflammatory M2 macrophages. This antibody was used therapeutically to block autoimmunity in a classic mouse model of spontaneous systemic lupus erythematosus.

TNF Counterbalances the Emergence of M2 Tumor Macrophages

Cancer can involve non-resolving, persistent inflammation where varying numbers of tumor-associated macrophages (TAMs) infiltrate and adopt different activation states between anti-tumor M1 and pro-tumor M2 phenotypes. Here, we resolve a cascade causing differential macrophage phenotypes in the tumor microenvironment. Reduction in TNF mRNA production or loss of type I TNF receptor signaling resulted in a striking pattern of enhanced M2 mRNA expression. M2 gene expression was driven in part by IL-13 from eosinophils co-recruited with inflammatory monocytes, a pathway that was suppressed by TNF. Our data define regulatory nodes within the tumor microenvironment that balance M1 and M2 populations. Our results show macrophage polarization in cancer is dynamic and dependent on the balance between TNF and IL-13, thus providing a strategy for manipulating TAMs.

A Neoglycoconjugate Containing the Human Milk Sugar LNFPIII Drives Anti-Inflammatory Activation of Antigen Presenting Cells in a CD14 Dependent Pathway

The milk pentasaccharide LNFPIII has therapeutic action for metabolic and autoimmune diseases and prolongs transplant survival in mice when presented as a neoglycoconjugate. Within LNFPIII is the Lewis^x trisaccharide, expressed by many helminth parasites. In humans, LNFPIII is found in human milk and also known as stage-specific embryonic antigen-1. LNFPIII-NGC drives alternative activation of macrophages and dendritic cells via NFκB activation in a TLR4 dependent mechanism. However, the connection between LNFPIII-NGC activation of APCs, TLR4 signaling and subsequent MAP kinase signaling leading to anti-inflammatory activation of APCs remains unknown. In this study we determined that the innate receptor CD14 was essential for LNFPIII-NGC induction of both ERK and NFkB activation in APCs. Induction of ERK activation by LNFPIII-NGC was completely dependent on CD14/TLR4-Ras-Raf1/TPL2-MEK axis in bone marrow derived dendritic cells (BMDCs). In addition, LNFPIII-NGC preferentially induced the production of Th2 “favoring” chemokines CCL22 and matrix metalloprotease protein-9 in a CD14 dependent manner in BMDCs. In contrast, LNFPIII-NGC induces significantly lower levels of Th1 “favoring” chemokines, MIP1α, MIP1β and MIP-2 compared to levels in LPS stimulated cells. Interestingly, NGC of the identical human milk sugar LNnT, minus the alpha 1–3 linked fucose, failed to activate APCs via TLR4/MD2/CD14 receptor complex, suggesting that the alpha 1–3 linked fucose in LNFPIII and not on LNnT, is required for this process. Using specific chemical inhibitors of the MAPK pathway, we found that LNFPIII-NGC induction of CCL22, MMP9 and IL-10 production was dependent on ERK activation. Over all, this study suggests that LNFPIII-NGC utilizes CD14/TLR4-MAPK (ERK) axis in modulating APC activation to produce anti-inflammatory chemokines and cytokines in a manner distinct from that seen for the pro-inflammatory PAMP LPS. These pathways may explain the in vivo therapeutic effect of LNFPIII-NGC treatment for inflammation based diseases.