Nasal Acai Polysaccharides Potentiate Innate Immunity to Protect against Pulmonary Francisella tularensis and Burkholderia pseudomallei Infections

Pulmonary Francisella tularensis and Burkholderia pseudomallei infections are highly lethal in untreated patients, and current antibiotic regimens are not always effective. Activating the innate immune system provides an alternative means of treating infection and can also complement antibiotic therapies. Several natural agonists were screened for their ability to enhance host resistance to infection, and polysaccharides derived from the Acai berry (Acai PS) were found to have potent abilities as an immunotherapeutic to treat F. tularensis and B. pseudomallei infections. In vitro, Acai PS impaired replication of Francisella in primary human macrophages co-cultured with autologous NK cells via augmentation of NK cell IFN-γ. Furthermore, Acai PS administered nasally before or after infection protected mice against type A F. tularensis aerosol challenge with survival rates up to 80%, and protection was still observed, albeit reduced, when mice were treated two days post-infection. Nasal Acai PS administration augmented intracellular expression of IFN-γ by NK cells in the lungs of F. tularensis-infected mice, and neutralization of IFN-γ ablated the protective effect of Acai PS. Likewise, nasal Acai PS treatment conferred protection against pulmonary infection with B. pseudomallei strain 1026b. Acai PS dramatically reduced the replication of B. pseudomallei in the lung and blocked bacterial dissemination to the spleen and liver. Nasal administration of Acai PS enhanced IFN-γ responses by NK and γδ T cells in the lungs, while neutralization of IFN-γ totally abrogated the protective effect of Acai PS against pulmonary B. pseudomallei infection. Collectively, these results demonstrate Acai PS is a potent innate immune agonist that can resolve F. tularensis and B. pseudomallei infections, suggesting this innate immune agonist has broad-spectrum activity against virulent intracellular pathogens

Polysaccharides from Agaricus bisporus and Agaricus brasiliensis show similarities in their structures and their immunomodulatory effects on human monocytic THP-1 cells

<p>Abstract</p> <p>Background</p> <p>Mushroom polysaccharides have traditionally been used for the prevention and treatment of a multitude of disorders like infectious illnesses, cancers and various autoimmune diseases. Crude mushroom extracts have been tested without detailed chemical analyses of its polysaccharide content. For the present study we decided to chemically determine the carbohydrate composition of semi-purified extracts from 2 closely related and well known basidiomycete species, i.e. <it>Agaricus bisporus </it>and <it>A. brasiliensis </it>and to study their effects on the innate immune system, in particular on the <it>in vitro </it>induction of pro-inflammatory cytokines, using THP-1 cells.</p> <p>Methods</p> <p>Mushroom polysaccharide extracts were prepared by hot water extraction and precipitation with ethanol. Their composition was analyzed by GC-MS and NMR spectroscopy. PMA activated THP-1 cells were treated with the extracts under different conditions and the production of pro-inflammatory cytokines was evaluated by qPCR.</p> <p>Results</p> <p>Semi-purified polysaccharide extracts of <it>A. bisporus </it>and <it>A. brasiliensis </it>(= <it>blazei</it>) were found to contain (1→6),(1→4)-linked α-glucan, (1→6)-linked β-glucan, and mannogalactan. Their proportions were determined by integration of ¹H-NMR signs, and were considerably different for the two species. <it>A. brasiliensis </it>showed a higher content of β-glucan, while <it>A. bisporus </it>presented mannogalactan as its main polysaccharide. The extracts induced a comparable increase of transcription of the pro-inflammatory cytokine genes IL-1β and TNF-α as well as of COX-2 in PMA differentiated THP-1 cells. Pro-inflammatory effects of bacterial LPS in this assay could be reduced significantly by the simultaneous addition of <it>A. brasiliensis </it>extract.</p> <p>Conclusions</p> <p>The polysaccharide preparations from the closely related species <it>A. bisporus </it>and <it>A. brasiliensis </it>show major differences in composition: <it>A. bisporus </it>shows high mannogalactan content whereas <it>A. brasiliensis </it>has mostly β-glucan. Semi-purified polysaccharide extracts from both <it>Agaricus </it>species stimulated the production of pro-inflammatory cytokines and enzymes, while the polysaccharide extract of <it>A. brasiliensis </it>reduced synthesis of these cytokines induced by LPS, suggesting programmable immunomodulation.</p

Targeting tumor-associated macrophages by anti-tumor Chinese materia medica

Tumor-associated macrophages (TAMs) play a key role in all stages of tumorigenesis and tumor progression. TAMs secrete different kinds of cytokines, chemokines, and enzymes to affect the progression, metastasis, and resistance to therapy depending on their state of reprogramming. Therapeutic benefit in targeting TAMs suggests that macrophages are attractive targets for cancer treatment. Chinese materia medica (CMM) is an important approach for treating cancer in China and in the Asian region. According to the theory of Chinese medicine (CM) and its practice, some prescriptions of CM regulate the body's internal environment possibly including the remodeling the tumor microenvironment (TME). Here we briefly summarize the pivotal effects of TAMs in shaping the TME and promoting tumorigenesis, invasion, metastasis and immunosuppression. Furthermore, we illustrate the effects and mechanisms of CMM targeting TAMs in antitumor therapy. Finally, we reveal the CMM's dual-regulatory and multi-targeting functions on regulating TAMs, and hopefully, provide the theoretical basis for CMM clinical practice related to cancer therapy

3-(1H-Indol-3-yl)-2-[3-(4-nitrophenyl)ureido]propanamide Derivatives are Agonists of Human Formyl Peptide Receptor 2

N-formyl peptide receptor (FPR1) and FPR2 are G protein-coupledreceptors (GPCR) involved in host defense and sensing cellular dysfunction. Previously we found that antagonists of gastrin-releasing peptide/neuromedin B receptors (BB1/BB2), PD168368 and PD176252, were potent mixed FPR1/FPR2 agonists [Mol. Pharm. (2011) 79: 77-90]. In the present studies, we screened 13 structural derivatives of PD176252 for their ability to activate human neutrophils and HL-60 cells transfected with human FPR1 or FPR2. While none of the compounds had BB2 antagonist activity, five of the compounds stimulated Ca2+ flux in HL-60 cells expressing FPR2, but not in HL-60 cells expressing FPR1, suggesting they were selective for FPR2. The most potent compounds EMY-96 [(R)3-(1H-indol-3-yl)-2-(3-(4-nitrophenyl)ureido)-N-((1-(pyridin-2-yl)cyclohexyl) methyl)propanamide] and its S-isomer ML-16 induced Ca2+ flux with EC50 values in the low micromolar range. Furthermore, pretreatment of FPR2/HL-60 cells with specific the FPR2 antagonist WRW4 prevented Ca2+ flux activated by EMY-96 and ML-16. Interestingly, neither EMY-96 nor ML-16 was able to induce Ca2+ flux in human neutrophils; however, EMY-96 desensitized human neutrophils and FPR2/HL-60 cells to subsequent activation by the hexapeptide WKYMVM. In addition, all five active compounds dose-dependently stimulated human neutrophil chemotaxis. Lastly, these compounds induced β-arrestin binding to FPR2. Thus, these 3-(1H-Indol-3-yl)-2-[3-(4-nitrophenyl)ureido] propanamide derivatives represent unique FPR2 agonists and exhibit novel properties in human neutrophils and FPR-transfected HL-60 cells. This work was supported in part by National Institutes of Health grant P20 RR-020185, National Institutes of Health contract HHSN266200400009C, an equipment grant from the M.J. Murdock Charitable Trust, and the Montana State University Agricultural Experimental Station

3-(1H-indol-3-yl)-2-[3-(4-nitrophenyl)ureido]propanamide enantiomers with human formyl-peptide receptor agonist activity: Molecular modeling of chiral recognition by FPR2.

N-formyl peptide receptors (FPRs) are G protein-coupled receptors (GPCRs) that play critical roles in inflammatory reactions, and FPR-specific interactions can possibly be used to facilitate the resolution of pathological inflammatory reactions. Recent studies indicated that FPRs have stereo-selective preference for chiral ligands. Here, we investigated the structure-activity relationship of 24 chiral ureidopropanamides, including previously reported compounds PD168368/PD176252 and their close analogs, and used molecular modeling to define chiral recognition by FPR2. Unlike previously reported 6-methyl-2,4-disubstituted pyridazin-3(2H)-ones, whose R-forms preferentially activated FPR1/FPR2, we found that four S-enantiomers in the seven ureidopropanamide pairs tested preferentially activated intracellular Ca(2+) flux in FPR2-transfected cells, while the R-counterpart was more active in two enantiomer pairs. Thus, active enantiomers of FPR2 agonists can be in either R- or S-configurations, depending on the molecular scaffold and specific substituents at the chiral center. Using molecular modeling approaches, including field point methodology, homology modeling, and docking studies, we propose a model that can explain stereoselective activity of chiral FPR2 agonists. Importantly, our docking studies of FPR2 chiral agonists correlated well with the FPR2 pharmacophore model derived previously. We conclude that the ability of FPR2 to discriminate between the enantiomers is the consequence of the arrangement of the three asymmetric hydrophobic subpockets at the main orthosteric FPR2 binding site with specific orientation of charged regions in the subpockets

Novel 3-(1H-indol-3-yl)-2-[3-(4-methoxyphenyl)ureido]propanamides as selective agonists of human formyl-peptide receptor 2.

N-formyl peptide receptors (FPRs) are G protein-coupled receptors (GPCRs) that play critical roles in inflammatory reactions, and FPR-specific interactions can possibly be used to facilitate the resolution of pathological inflammatory reactions. We here report the synthesis and biological evaluation of six pairs of chiral ureidopropanamido derivatives as potent and selective formyl peptide receptor-2 (FPR2) agonists, that were designed starting from our lead agonist (S)-3-(1H-indol-3-yl)-2-[3-(4-methoxyphenyl)ureido]-N-[[1-(5-methoxy-2-pyridinyl)cyclohexyl]methyl]propanamide ((S)-9a). The new compounds were obtained in overall yields considerably higher than (S)-9a. Various of the new compounds showed agonist properties comparable to that of (S)-9a along with higher selectivity over FPR1. Molecular modeling was used to define chiral recognition by FPR2. In vitro metabolic stability of selected compounds was also assessed to obtain preliminary insight on drug-like properties of this class of compounds