Key Vitamin D Target Genes with Functions in the Immune System.

The biologically active form of vitamin D3, 1α,25-dihydroxyvitamin D3 (1,25(OH)2D3), modulates innate and adaptive immunity via genes regulated by the transcription factor vitamin D receptor (VDR). In order to identify the key vitamin D target genes involved in these processes, transcriptome-wide datasets were compared, which were obtained from a human monocytic cell line (THP-1) and peripheral blood mononuclear cells (PBMCs) treated in vitro by 1,25(OH)2D3, filtered using different approaches, as well as from PBMCs of individuals supplemented with a vitamin D3 bolus. The led to the genes ACVRL1, CAMP, CD14, CD93, CEBPB, FN1, MAPK13, NINJ1, LILRB4, LRRC25, SEMA6B, SRGN, THBD, THEMIS2 and TREM1. Public epigenome- and transcriptome-wide data from THP-1 cells were used to characterize these genes based on the level of their VDR-driven enhancers as well as the level of the dynamics of their mRNA production. Both types of datasets allowed the categorization of the vitamin D target genes into three groups according to their role in (i) acute response to infection, (ii) infection in general and (iii) autoimmunity. In conclusion, 15 genes were identified as major mediators of the action of vitamin D in innate and adaptive immunity and their individual functions are explained based on different gene regulatory scenarios.

Gum Acacia mitigates diclofenac nephrotoxicity by targeting monocyte chemoattractant protein-1, complement receptor-1 and pro-apoptotic pathways.

Treatment of many inflammatory diseases involves a chronic use of NSAIDs in large doses increasing acute kidney injury risk. This study was designed to evaluate a potential renoprotective effect of Gum Acacia (GA) on diclofenac (DICF) induced nephrotoxicity. Six groups of rats were used: normal group; control group (deprived from water during week 13), DICF group (deprived from water during week 13 and injected DICF i.p. 15 mg/kg/12 h at days 4 through 6 of water deprivation days, GA groups (1, 2 or 3 g/kg/day in drinking water) for 12 weeks followed by water deprivation and DICF injection as described. Kidney function, oxidative stress and anti-oxidant biomarkers were measured. Interleukin-1ß, IL-10, TNF-α, complement receptor (CR)-1, monocyte chemoattractant protein (MCP)-1 and caspase-3 were assessed. Kidney sections were scored for fibrosis, tubular injury and inflammatory cells. An elevation in renal biomarkers, inflammatory cytokines, malondialdehyde and apoptotic markers was observed after DICF injection (p < 0.001). Gum Acacia (mostly 3 g/kg) markedly reduced fibrosis, tubular injury, IL-1ß, TNF-α, caspase-3 and MCP-1 levels (p < 0.01). It increased IL-10, anti-oxidant capacity, CR-1 level in the kidney (p < 0.001). Protective effect may be mediated by antioxidant, anti-inflammatory and anti-apoptotic mechanisms besides interfering with monocytes and complement mediated tissue damage pathways.

Preclinical Evaluation of AdVince, an Oncolytic Adenovirus Adapted for Treatment of Liver Metastases from Neuroendocrine Cancer.

Cancer immunotherapy is becoming a cornerstone in the clinical care of cancer patients due to the breakthrough trials with immune checkpoint blockade antibodies and chimeric antigen receptor T cells. The next breakthrough in cancer immunotherapy is likely to be oncolytic viruses engineered to selectively kill tumor cells and deceive the immune system to believe that the tumor is a foreign entity that needs to be eradicated. We have developed AdVince, an oncolytic adenovirus for treatment of liver metastases from neuroendocrine tumor (NET). AdVince includes the gene promoter from human chromogranin A for selective replication in neuroendocrine cells, miR122 target sequences for reduced liver toxicity, and a cell-penetrating peptide in the capsid for increased infectivity of tumor cells and optimized spread within tumors. This paper describes the preclinical evaluation of AdVince on freshly isolated human gastrointestinal NET cells resected from liver metastases and freshly isolated human hepatocytes as well as in fresh human blood. AdVince selectively replicates in and kills NET cells. Approximately 73-fold higher concentration of AdVince is needed to induce a similar level of cytotoxicity in NET cells as in hepatocytes. AdVince did not activate complement or induce considerable amount of proinflammatory cytokines or chemokines in human blood. The data presented herein indicate that AdVince can be safely evaluated in a phase I/IIa clinical trial for patients with liver-dominant NET.

Basics of the medical use of ayahuasca: physiology of dimethyltryptamine.

Ayahuasca is a brew made of two admixture plants containing dimethyltryptamine (DMT) and b-carbolines (harmine and tetrahydroharmine). The indigenous groups of the Amazonas basin have been using it for centuries as an ethnomedical substance in healing and spiritual-religious rituals. During the last two decades the brew has raised increased scientific and public interest worldwide about its healing effects. Present paper addresses the therapeutic potentials of ayahuasca use and outlines the cellular mechanisms behind - in focus of the Q-1 receptor mediated action of DMT. The scientific investigation of ayahuasca is complicated by methodical problems, legal issues, and sociocultural pre-conceptions.

Potent heterocyclic ligands for human complement c3a receptor.

The G-protein coupled receptor (C3aR) for human inflammatory protein complement C3a is an important component of immune, inflammatory, and metabolic diseases. A flexible compound (N2-[(2,2-diphenylethoxy)acetyl]-l-arginine, 4), known as a weak C3aR antagonist (IC50 µM), was transformed here into potent agonists (EC50 nM) of human macrophages (Ca(2+) release in HMDM) by incorporating aromatic heterocycles. Antagonists were also identified. A linear correlation between binding affinity for C3aR and calculated hydrogen-bond interaction energy of the heteroatom indicated that its hydrogen-bonding capacity influenced ligand affinity and function mediated by C3aR. Hydrogen-bond accepting heterocycles (e.g., imidazole) conferred the highest affinity and agonist potency (e.g., 21, EC50 24 nM, Ca(2+), HMDM) with comparable efficacy and immunostimulatory activity as that of C3a in activating human macrophages (Ca(2+), IL1ß, TNFα, CCL3). These potent and selective modulators of C3aR, inactivated by a C3aR antagonist, are stable C3a surrogates for interrogating roles for C3aR in physiology and disease.

Inhibitory effects of areca nut extract on expression of complement receptors and fc receptors in human neutrophils.

BACKGROUND: Chewing of areca quid increases the prevalence of periodontal diseases. Areca nut extract (ANE) inhibits the phagocytic activity of human neutrophils. This in vitro study investigates the effects of ANE on complement- and antibody-opsonized phagocytosis by neutrophils. Expression of complement receptors, Fc receptors, and F-actin in ANE-treated neutrophils is also analyzed. METHODS: The viability of ANE-treated neutrophils was determined using the propidium iodide staining method. The possible effects of ANE on the expression of complement receptors and Fc receptors were examined using an immunofluorescence staining method followed by flow cytometry and confocal laser scanning microscopy. The phagocytic activity of neutrophils against complement or immunoglobulin (Ig)G-opsonized fluorescent beads was analyzed using flow cytometry. Expression of F-actin was determined using confocal laser scanning microscopy. RESULTS: ANE significantly inhibited the production of complement receptors (CR1, CR3, and CR4) and Fc receptors (FcγRII and FcγRIII) in a concentration-dependent manner. Treatment of neutrophils with ANE significantly impaired their ability to phagocytose fluorescent beads. ANE also inhibited phagocytosis of fluorescent beads that were opsonized by complement or IgG. Moreover, expression of F-actin was inhibited after ANE treatment. CONCLUSIONS: ANE inhibits the complement- and IgG-mediated neutrophil phagocytosis that may result from reduction of the expression of complement receptors, Fc receptors, and F-actin formation after ANE treatment. The findings suggest that areca nut chewing may jeopardize the defensive functions of neutrophils and affect periodontal health.

Dysregulation of complement system and CD4+ T cell activation pathways implicated in allergic response.

Allergy is a complex disease that is likely to involve dysregulated CD4+ T cell activation. Here we propose a novel methodology to gain insight into how coordinated behaviour emerges between disease-dysregulated pathways in response to pathophysiological stimuli. Using peripheral blood mononuclear cells of allergic rhinitis patients and controls cultured with and without pollen allergens, we integrate CD4+ T cell gene expression from microarray data and genetic markers of allergic sensitisation from GWAS data at the pathway level using enrichment analysis; implicating the complement system in both cellular and systemic response to pollen allergens. We delineate a novel disease network linking T cell activation to the complement system that is significantly enriched for genes exhibiting correlated gene expression and protein-protein interactions, suggesting a tight biological coordination that is dysregulated in the disease state in response to pollen allergen but not to diluent. This novel disease network has high predictive power for the gene and protein expression of the Th2 cytokine profile (IL-4, IL-5, IL-10, IL-13) and of the Th2 master regulator (GATA3), suggesting its involvement in the early stages of CD4+ T cell differentiation. Dissection of the complement system gene expression identifies 7 genes specifically associated with atopic response to pollen, including C1QR1, CFD, CFP, ITGB2, ITGAX and confirms the role of C3AR1 and C5AR1. Two of these genes (ITGB2 and C3AR1) are also implicated in the network linking complement system to T cell activation, which comprises 6 differentially expressed genes. C3AR1 is also significantly associated with allergic sensitisation in GWAS data.

IgG antibodies in food allergy influence allergen-antibody complex formation and binding to B cells: a role for complement receptors.

Allergen-IgE complexes are more efficiently internalized and presented by B cells than allergens alone. It has been suggested that IgG Abs induced by immunotherapy inhibit these processes. Food-allergic patients have high allergen-specific IgG levels. However, the role of these Abs in complex formation and binding to B cells is unknown. To investigate this, we incubated sera of peanut- or cow's milk-allergic patients with their major allergens to form complexes and added them to EBV-transformed or peripheral blood B cells (PBBCs). Samples of birch pollen-allergic patients were used as control. Complex binding to B cells in presence or absence of blocking Abs to CD23, CD32, complement receptor 1 (CR1, CD35), and/or CR2 (CD21) was determined by flow cytometry. Furthermore, intact and IgG-depleted sera were compared. These experiments showed that allergen-Ab complexes formed in birch pollen, as well as food allergy, contained IgE, IgG1, and IgG4 Abs and bound to B cells. Binding of these complexes to EBV-transformed B cells was completely mediated by CD23, whereas binding to PBBCs was dependent on both CD23 and CR2. This reflected differential receptor expression. Upon IgG depletion, allergen-Ab complexes bound to PBBCs exclusively via CD23. These data indicated that IgG Abs are involved in complex formation. The presence of IgG in allergen-IgE complexes results in binding to B cells via CR2 in addition to CD23. The binding to both CR2 and CD23 may affect Ag processing and presentation, and (may) thereby influence the allergic response.

Complement and autoimmunity.

The complement system is a component of the innate immune system. Its main function was initially believed to be limited to the recognition and elimination of pathogens through direct killing or stimulation of phagocytosis. However, in recent years, the immunoregulatory functions of the complement system were demonstrated and it was determined that the complement proteins play an important role in modulating adaptive immunity and in bridging innate and adaptive responses. When the delicate mechanisms that regulate this sophisticated enzymatic system are unbalanced, the complement system may cause damage, mediating tissue inflammation. Dysregulation of the complement system has been involved in the pathogenesis and clinical manifestations of several autoimmune diseases, such as systemic lupus erythematosus, vasculitides, Sjögren's syndrome, antiphospholipid syndrome, systemic sclerosis, dermatomyositis, and rheumatoid arthritis. Complement deficiencies have been associated with an increased risk to develop autoimmune disorders. Because of its functions, the complement system is an attractive therapeutic target for a wide range of diseases. Up to date, several compounds interfering with the complement cascade have been studied in experimental models for autoimmune diseases. The main therapeutic strategies are inhibition of complement activation components, inhibition of complement receptors, and inhibition of membrane attack complex. At present, none of the available agents was proven to be both safe and effective for treatment of autoimmune diseases in humans. Nonetheless, data from preclinical studies and initial clinical trials suggest that the modulation of the complement system could constitute a viable strategy for the treatment of autoimmune conditions in the decades to come.

Retrieving novel C5aR antagonists using a hybrid ligand-based virtual screening protocol based on SVM classification and pharmacophore models.

C5aR antagonists have been thought as potential immune mediators in various inflammatory and autoimmune diseases, and discovery of C5aR antagonists has attracted much attention in recent years. The discovery of C5aR antagonists was usually achieved through high-throughput screening, which usually suffered a high cost and a low success rate. Currently, the fast developing computer-aided virtual screening (VS) methods provide economic and rapid approaches to the lead discovery. In this account, we proposed a hybrid ligand-based VS protocol that is based on support vector machine (SVM) classification and pharmacophore models for retrieving novel C5aR antagonists. Performance evaluation of this hybrid VS protocol in virtual screening against a large independent test set, T-CHEM, showed that the hybrid VS approach significantly increased the hit rate and enrichment factor compared with the individual SVM classification model-based VS and pharmacophore model-based VS, as well as molecular docking-based VS in that the receptor structure was created by homology modeling. The hybrid VS approach was then used to screen several large chemical libraries including PubChem, Specs, and Enamine. Finally, a total of 20 compounds were selected from the top ranking hits, and shifted to the subsequent in vitro and in vivo studies, which results will be reported in the near future.

Efficient osteoclast differentiation requires local complement activation.

Previous studies using blocking antibodies suggested that bone marrow (BM)-derived C3 is required for efficient osteoclast (OC) differentiation, and that C3 receptors are involved in this process. However, the detailed underlying mechanism and the possible involvement of other complement receptors remain unclear. In this report, we found that C3(-/-) BM cells exhibited lower RANKL/OPG expression ratios, produced smaller amounts of macrophage colony-stimulating factor and interleukin-6 (IL-6), and generated significantly fewer OCs than wild-type (WT) BM cells. During differentiation, in addition to C3, WT BM cells locally produced all other complement components required to activate C3 and to generate C3a/C5a through the alter-native pathway, which is required for efficient OC differentiation. Abrogating C3aR/C5aR activity either genetically or pharmaceutically suppressed OC generation, while stimulating WT or C3(-/-) BM cells with exogenous C3a and/or C5a augmented OC differentiation. Furthermore, supplementation with IL-6 rescued OC generation from C3(-/-) BM cells, and neutralizing antibodies to IL-6 abolished the stimulatory effects of C3a/C5a on OC differentiation. These data indicate that during OC differentiation, BM cells locally produce components, which are activated through the alternative pathway to regulate OC differentiation. In addition to C3 receptors, C3aR/C5aR also regulate OC differentiation, at least in part, by modulating local IL-6 production.

Effect of the C3a-receptor antagonist SB 290157 on anti-OVA polyclonal antibody-induced arthritis.

It was investigated whether the C3a-receptor antagonist (C3aRA) SB 290157 was involved in the suppression of anti-OVA pAb-induced arthritis because it is well known that anaphylatoxin C3a plays a crucial role in the development of an effective inflammatory response during complement activation. Anti-OVA pAb-induced arthritis was induced in DBA/1J mice by administration of anti-OVA pAb 0.5 h prior to intra-articular (i.a.) injection of OVA (0 h). Two peaks of joint swelling were observed at 0.5 and 3 h. The role of C3aRA in arthritis was investigated by injection of SB 290157 at concentrations of 10 and 30 mg/kg at 0 and 2 h. The antagonist was able to reduce joint swelling only at 3 h, and about 50% inhibition of joint swelling was observed with the concentration of 30 mg/kg. The C3 level was significantly decreased at 3 h compared with naïve mice showing complement consumption. Furthermore, the C3 activation was observed and increased corresponding to the graded concentration of anti-OVA pAb. The results also revealed that the C3aRA was able to reduce the expression of IL-1beta in synovial tissue. Taken together, the results suggested that C3aRA may be effective in the inhibition of arthritis.

Sequence-derived three-dimensional pharmacophore models for G-protein-coupled receptors and their application in virtual screening.

G-protein-coupled receptors (GPCRs) comprise a large protein family of significant past and current interest of pharmaceutical research. X-ray crystallography and molecular modeling combined with site-directed mutagenesis studies suggest that most family A GPCRs share a small-molecule binding site located in the outer part of the seven-transmembrane (7TM) bundle. Here we describe an automated method to derive sequence-derived three-dimensional (3D) pharmacophore models capturing the key elements for addressing this binding site by a small-molecule ligand. We have generated structure-based pharmacophore models from 10 homology models and 3 X-ray structures of receptor-ligand complexes. These 13 pharmacophores have been dissected into 35 different single-feature pharmacophore elements, each associated with a sequence motif or chemoprint, describing its molecular interaction partner(s) in the receptor. Subsequently, the protein sequences of 270 GPCRs have been searched for the presence of chemoprints and the appropriate single-feature pharmacophores have been assembled into three- to seven-feature 3D-pharmacophore models for each human family A GPCR. These models can be applied for virtual screening and for the design of subfamily directed libraries. A case study demonstrates the successful application of this approach for the identification of potent agonists for the complement component 3a receptor 1 (C3AR1) by virtual screening.

[Effects of Astragalus heteropolysaccharides on erythrocyte immune adherence function of mice with adjuvant-induced arthritis].

Astragalus heteropolysaccharides (AHPS) is obtained from the dried roots of Astragalus membranaceus (Fisch.) Bunge var. mongholious (Bunge) Hsiao. In the present study, we observed its effects on erythrocyte immune adherence function in mice with adjuvant-induced arthritis (AA). The mice were treated intragastrically with AHPS of 1 000, 500, and 250 mg x kg(-1) x d(-1) separately and treated with tripterygium glycosides (TG) of 60 mg x kg(-1) x d(-1) as positive control. The number of complement receptor type 1 (CR1) on erythrocyte, the concentration of circulating immune complex (CIC) in serum and the amount of immune complex (IC) deposition in synovium of knee joint were determined by flow cytometry, polyethylene glycol (PEG-6000) precipitation and ponceau S (P-S) staining and fluorescent immunohistochemistry respectively. The pathological change of knee joint was evaluated by histological section. The results showed that both AHPS and TG improved significantly the primary and secondary local or systemic symptoms of the mice with AA and reduced the synovium hyperplasia, inflammatory cell infiltrate, pannus and cartilage demolish of knee joint, and AHPS of 1 000, 500, and 250 mg x kg(-1) x d(-1) could significantly increase the number of CR1 on erythrocyte, improve the elimination of CIC in the peripheral blood and reduce the deposition of IC in joint synovium in a dose-dependent manner (P < 0.01 or P < 0.05). The results indicate that one of the therapeutic effective mechanisms of AHPS on mice with AA could be to increase gene expression of CR1 of mice with AA.

Effects of Astragalus heteropolysaccharides on erythrocyte immune adherence function of mice with adjuvant-induced arthritis / 药学学报

Astragalus heteropolysaccharides (AHPS) is obtained from the dried roots of Astragalus membranaceus (Fisch.) Bunge var. mongholious (Bunge) Hsiao. In the present study, we observed its effects on erythrocyte immune adherence function in mice with adjuvant-induced arthritis (AA). The mice were treated intragastrically with AHPS of 1 000, 500, and 250 mg x kg(-1) x d(-1) separately and treated with tripterygium glycosides (TG) of 60 mg x kg(-1) x d(-1) as positive control. The number of complement receptor type 1 (CR1) on erythrocyte, the concentration of circulating immune complex (CIC) in serum and the amount of immune complex (IC) deposition in synovium of knee joint were determined by flow cytometry, polyethylene glycol (PEG-6000) precipitation and ponceau S (P-S) staining and fluorescent immunohistochemistry respectively. The pathological change of knee joint was evaluated by histological section. The results showed that both AHPS and TG improved significantly the primary and secondary local or systemic symptoms of the mice with AA and reduced the synovium hyperplasia, inflammatory cell infiltrate, pannus and cartilage demolish of knee joint, and AHPS of 1 000, 500, and 250 mg x kg(-1) x d(-1) could significantly increase the number of CR1 on erythrocyte, improve the elimination of CIC in the peripheral blood and reduce the deposition of IC in joint synovium in a dose-dependent manner (P < 0.01 or P < 0.05). The results indicate that one of the therapeutic effective mechanisms of AHPS on mice with AA could be to increase gene expression of CR1 of mice with AA.

Larrea divaricata Cav (Jarilla): production of superoxide anion, hydrogen peroxide and expression of zymosan receptors.

Larrea divaricata is a plant widely used in folk medicine in Argentina. This work aimed to study the mechanisms of decoction activity on the release of oxygen reactive species. Decoction increased the binding of zymosan-FITC and superoxide production. Cadmium decreased the superoxide production as well as malonate and barbital. Decoction decreased the release of hydrogen peroxide. Decoction increased the reduction of MTT but not when malonate and barbital were included. Together, decoction increased the expression of dectin-1 leading to increased superoxide production. It is possible that decoction increases the activity of peroxidase, and decreases the Cu, Zn-superoxide dismutase.

Pre-clinical evaluation of an sLe x-glycosylated complement inhibitory protein in a non-human primate model of reperfused stroke.

BACKGROUND: Soluble complement receptor-1 (sCR1), a potent complement inhibitor, confers neuroprotection in a murine stroke model. Additional neuroprotective benefit is achieved by sLe x-glycosylation of sCR1. In an effort to translate sCR1-sLe x to clinical trials, we evaluated this agent in a primate stroke model. METHODS: Adult male baboons randomly received either sCR1-sLe x or vehicle. Stroke volume was assessed on day 3, and neurological examinations were conducted daily. Complement activity (CH50) was measured at 30 minute, 2, 6, 12 hour, 3, and 10 days post-ischemia. RESULTS: The experiment was terminated prematurely following an interim analysis. In a preliminary cohort (n = 3 per arm), infarct volume was greater in the treated animals. No difference in neurological score was found between groups. CH50 levels were significantly reduced in the sCR1sLe x-treated groups. A hypotensive response was also observed in animals treated with sCR1-sLe x. Conclusions Further work is necessary to explain the hypotensive response observed in primates prior to further clinical development of sCR1-sLe x.

Genetic deficiency of C3 as well as CNS-targeted expression of the complement inhibitor sCrry ameliorates experimental autoimmune uveoretinitis.

In this report, we describe the effect of complement deficiency and inhibition on experimental autoimmune uveoretinitis (EAU). C57BL/6 mice genetically deficient in C3 (C3-/-) or expressing a soluble complement activation inhibitor (soluble complement receptor related protein Y or sCrry) in a CNS-targeted fashion, (sCrry/GFAP) were induced for EAU via peripheral immunisation with a peptide of amino acids 1-20 of human interphotoreceptor retinoid binding protein in complete Freund's adjuvant with concurrent intraperitoneal pertussis toxin. The incidence and severity of EAU in the mutant mice was compared with that in simultaneously induced C57BL/6 wild type mice. The sCrry protein was detected in retinal extracts from transgenic but not wild type mice by western blot. C3-/- mice had a significant reduction in the incidence of EAU compared with wild type mice (incidence 44 versus 89%, respectively, p=0.0417) and a significant reduction in the severity of EAU (median disease score values 0 versus 1.3, respectively, p=0.0253). Similarly, sCrry mice had a significant reduction in the incidence of EAU compared with wild type mice (incidence 57 versus 100% respectively, p=0.0033) and a significant reduction in the severity of EAU (median disease score values 0.18 versus 1.85, respectively, p=0.0054). A genetic deficiency of C3 and production of a soluble complement inhibitor targeted to the CNS and eye are protective against EAU.

Drug evaluation: the C5a receptor antagonist PMX-53.

Peptech is developing PMX-53, a complement C5a inhibitor for the potential treatment of inflammatory disorders, including rheumatoid arthritis and psoriasis. Phase Ib/IIa clinical trials have been completed for both indications.