Influence of glucose on swarming and quorum sensing of Dickeya solani.

Dickeya solani is a pathogen most frequently responsible for infecting potato plants in Europe. As in the case of most plant pathogens, its ability to colonize and invade the host depends on chemotaxis and motility. The coordinated movement of Dickeya over solid surfaces is governed by a quorum sensing mechanism. In D. solani motility is regulated by ExpI-ExpR proteins, homologous to luxI-luxR system from Vibrio fisheri, in which N-acyl-homoserine lactones (AHLs) serve as signaling molecules. Moreover, in many Gram-negative bacteria motility is coupled with central metabolism via carbon catabolite repression. This enables them to reach more nutrient-efficient niches. The aim of this study was to analyze the swarming motility of D. solani depending on the volume of the medium in the cultivation plate and glucose content. We show that the ability of this bacterium to move is strictly dependent on both these factors. Moreover, we analyze the production of AHLs and show that the quorum sensing mechanism in D. solani is also influenced by the availability of glucose in the medium and that the distribution of these signaling molecules are different depending on the volume of the medium in the plate.

The effect of an isoquinoline alkaloid on treatment of periodontitis by regulating the neutrophils chemotaxis.

Neutrophil plays a critical role in the progression of periodontitis. In general, its chemotaxis and activation are benefit for the host defense of bacterial infection and inflammation. However, previous studies have reported that the hyperactive and reactive neutrophils appear to be one of the reasons for tissue destruction in periodontitis tissues. In this study, we investigated an isoquinoline alkaloid Litcubanine A (LA), which from the Traditional Chinese medicinal plant, Litsea cubeba. We found LA showed significant activity in inhibiting neutrophils chemotaxis in the zebrafish yolk sac microinjection model in vivo and in mouse neutrophils in vitro. Further investigation proved that LA could inhibit the expression levels of neutrophil respiratory burst-related and inflammation-related genes CYBB and NCF2, as well as inhibit the activation of MAPK signaling pathway. Moreover, using LA, we successfully achieved the effect of reducing periodontitis bone loss by regulating neutrophil chemotaxis and related functions in a mouse ligature-induced periodontitis model.

Effects of Euphorbia umbellata extracts on complement activation and chemotaxis of neutrophils.

ETHNOPHARMACOLOGICAL RELEVANCE: The species Euphorbia umbellata (leitosinha) has been traditionally used for the treatment of inflammatory diseases and cancer. AIM OF THE STUDY: Evaluation the effect of E. umbellata latex extracts obtained with hexane, chloroform, ethyl acetate and methanol on the activation of the complement pathways and neutrophil chemotaxis. MATERIALS AND METHODS: The latex was partitioned using Soxhlet apparatus and hexane, chloroform, ethyl acetate and methanol as solvents. The classical and alternative pathway activity were performed by hemolytic assays with sensitized sheep or rabbit erythrocytes, respectively; the lectin pathway activity was quantified by ELISA, through the measurement of C4 molecules and the chemotaxis of human neutrophils was performed using 1% casein as the chemotactic inducer and Boyden's chamber. GC-Q-ToF and NMR analyses were applied to evaluate the chemical composition of E. umbellata latex extracts. RESULTS: All E. umbellata latex extracts exhibited an inhibitory effect on the activation of the alternative pathway. Methanol and ethyl acetate extracts inhibited the classical pathway while chloroform extract activated this pathway. Ethyl acetate and hexane extracts inhibited lectin activation. All E. umbellata extracts inhibited casein-induced neutrophil chemotaxis. Terpenes and phenolic compounds have been suggested to be present in the E. umbellta latex extracts. CONCLUSION: The E. umbellata latex was able to modulate the functions of the immune system. Thus, it is possible to infer that the terpenes and phenolic compounds of the phytocomplex of E. umbellata latex can contribute for the activity on the complement pathways.

Oral Administration of Aloe vera Ameliorates Wound Healing through Improved Angiogenesis and chemotaxis in Sprague Dawley Rats.

BACKGROUND: Aloe vera has been reported as a topical antibiotic and healing agent for wounds, but advantages of oral administration and mechanisms of wound healing have not been reported. Present study focuses on the evaluation of effects of oral administration of Aloe vera for excisional cutaneous wounds in Sprague Dawley rats. METHODS: Sprague Dawley (SD) rats were inflicted with excisional wounds and were either treated with Aloe vera orally (Aloe vera) or kept untreated (wound). In contrast, healthy rats were kept as control group. Wound area was measured from day 7th to day 21st. Collagen content was estimated by hydroxyproline assay. Histology was analysed by hematoxylin and eosin staining. Angiogenesis was observed by indirect ELISA for Insulin like Growth Factor (IGF-1) and Vascular Endothelial Growth Factor (VEGF) protein from skin, serum and bone marrow. Chemotaxis was evaluated by RT-PCR analysis for Stromal cell-Derived Factor-1 (SDF-1) and C-X-C chemokine receptor type 4 (CXCR-4) from skin and bone marrow. RESULTS: Aloe vera healed wounds earlier than untreated rats with gradual improvement in wound areas and collagen content. Aloe vera also improved the expression of IGF-1 and VEGF in skin and bone marrow indicating an improvement in angiogenesis. RT- PCR analysis showed increased expression of genes for chemotaxis (SDF-1 and CXCR-4) in skin and bone marrow. CONCLUSION: Aloe vera improves healing by increasing collagen content, improving angiogenesis and chemotaxis.

Vitamin D/CD46 Crosstalk in Human T Cells in Multiple Sclerosis.

Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system (CNS), in which T-cell migration into the CNS is key for pathogenesis. Patients with MS exhibit impaired regulatory T cell populations, and both Foxp3+ Tregs and type I regulatory T cells (Tr1) are dysfunctional. MS is a multifactorial disease and vitamin D deficiency is associated with disease. Herein, we examined the impact of 1,25(OH)2D3 on CD4+ T cells coactivated by either CD28 to induce polyclonal activation or by the complement regulator CD46 to promote Tr1 differentiation. Addition of 1,25(OH)2D3 led to a differential expression of adhesion molecules on CD28- and CD46-costimulated T cells isolated from both healthy donors or from patients with MS. 1,25(OH)2D3 favored Tr1 motility though a Vitamin D-CD46 crosstalk highlighted by increased VDR expression as well as increased CYP24A1 and miR-9 in CD46-costimulated T cells. Furthermore, analysis of CD46 expression on T cells from a cohort of patients with MS supplemented by vitamin D showed a negative correlation with the levels of circulating vitamin D. Moreover, t-Distributed Stochastic Neighbor Embedding (t-SNE) analysis allowed the visualization and identification of clusters increased by vitamin D supplementation, but not by placebo, that exhibited similar adhesion phenotype to what was observed in vitro. Overall, our data show a crosstalk between vitamin D and CD46 that allows a preferential effect of Vitamin D on Tr1 cells, providing novel key insights into the role of an important modifiable environmental factor in MS.

Discovery of BMS-986235/LAR-1219: A Potent Formyl Peptide Receptor 2 (FPR2) Selective Agonist for the Prevention of Heart Failure.

Formyl peptide receptor 2 (FPR2) agonists can stimulate resolution of inflammation and may have utility for treatment of diseases caused by chronic inflammation, including heart failure. We report the discovery of a potent and selective FPR2 agonist and its evaluation in a mouse heart failure model. A simple linear urea with moderate agonist activity served as the starting point for optimization. Introduction of a pyrrolidinone core accessed a rigid conformation that produced potent FPR2 and FPR1 agonists. Optimization of lactam substituents led to the discovery of the FPR2 selective agonist 13c, BMS-986235/LAR-1219. In cellular assays 13c inhibited neutrophil chemotaxis and stimulated macrophage phagocytosis, key end points to promote resolution of inflammation. Cardiac structure and functional improvements were observed in a mouse heart failure model following treatment with BMS-986235/LAR-1219.

[Effect of butyl alcohol extract of Baitouweng Decoction on vaginal mucosal neutrophil chemotaxis in vulvovaginal candidiasis mice].

To investigate the effects of butyl alcohol extract of Baitouweng Decoction(BAEB) on neutrophil chemotaxis in vaginal mucosa of mice with vulvovaginal candidiasis(VVC). Seventy-two SPF female Kunming mice were randomly divided into normal control group, model group, fluconazole group, BAEB low-dose group, middle-dose group and high-dose group. Subcutaneous injection of estradiol benzoate was conducted to induce pseudo-estrus, and then 2×10~6 CFU·mL~(-1)of Candida albicans was inoculated into vaginal lumen, followed by drug treatment for 7 days. Gram staining was used to observe the morphological changes of C. albicans in vagina; vaginal fungal load was detected on agar plate. Histological changes of vaginal tissues in mice were observed by HE staining. Lactate dehydrogenase(LDH), interleukin-6(IL-6) and tumor necrosis factor(TNF-α) levels in mouse lavage fluid were detected by enzyme-linked immunosorbent assay(ELISA). Neutrophils in vaginal lavage fluid was observed and counted by using Pap smear. The levels of IL-8 and MIP-2 in vaginal mucosa were detected by ELISA. IL-8 and MIP-2 mRNA levels in vaginal mucosa of mice were detected by qRT-PCR. The results showed that as compared with the normal group, VVC model group had a large number of hyphae and a high level of fungal loadinvagina. The vaginal mucosa was completely destroyed, the number of neutrophils increased, and the protein and mRNA levels of IL-8 and MIP-2 were up-regulated. After BAEB treatment, the hyphae of the treatment group was decreased, the fungal load was decreased, the impaired mucosa showed different degrees of improvement, the inflammatory factors were decreased to varying degrees, and the protein and mRNA levels of chemokine IL-8 and MIP-2 were down-regulated. In conclusion, BAEB may be used to treat VVC by inhibiting vulvovaginal candidiasis via blocking neutrophils recruitment into vagina.

Bioguided identification of daucosterol, a compound that contributes to the cytotoxicity effects of Crateva adansonii DC (capparaceae) to prostate cancer cells.

ETHNOPHARMACOLOGICAL RELEVANCE: Crateva adansonii DC (Capparaceae) is a shrub used to treat tumors in Cameroon. In our previous reports, a Crateva adansonii dichloromethane-methanol (DCM/MeOH) extract was shown to prevent chemically induced tumors in Wistar rats. AIM OF STUDY: To determine the bioactive principle of Crateva adansonii extract and to elucidate its underlying mechanism. MATERIALS AND METHODS: An activity-guided fractionation was realized using MTT assay. To investigate if the bioactive compound daucosterol (CA2) accounted for the previously observed anticancer effects of the C. adansonii extract, it was tested on cell growth, cell proliferation, cell cycle, cell death mechanism and cell migration. In addition, cell cycle- and apoptosis-regulating proteins were assessed by Western blotting. RESULTS: Daucosterol (CA2), a steroid saponin, was identified as major anticancer principle of the C. adansonii extract. Daucosterol significantly inhibited LNCaP, DU145 and PC3 prostate carcinoma cell growth and proliferation at the optimal concentration of 1 µg/mL. It also significantly increased the number of late apoptotic (DU145) and apoptotic (PC3) cells. The number of cells in S phase increased in DU145, while the number of G0/G1 cells decreased. Cell cycle proteins (cdk1, pcdk1, cyclin A and B) were down-regulated in DU145 and PC3 cells, whereas only cdk2 was down-regulated in PC3 cells. Moreover, the anti-apoptotic Akt, pAKT and Bcl-2 proteins were down-regulated, while the pro-apoptotic protein Bax was up-regulated. CA2 induced anti-metastatic effects by decreasing chemotaxis and cell migration, while it increased cell adhesion to fibronectin and collagen matrix. CONCLUSION: These results suggest that daucosterol is the major active principle responsible at least in part for the anticancer effect of the extract of Crateva adansonii.

Amygdalin Modulates Prostate Cancer Cell Adhesion and Migration In Vitro.

The natural compound, amygdalin, is notably popular with prostate cancer patients as an alternative or complementary treatment option. However, knowledge about its mode of action is sparse. We investigated amygdalin's impact on prostate cancer adhesion and motile behavior. DU-145 and PC3 cancer cells were exposed to amygdalin. Adhesion to human vascular endothelium or immobilized collagen was then explored. The influence of amygdalin on chemotaxis and migration was also investigated, as well as amygdalin induced alteration to surface and total cellular α and ß integrin expression. Integrin knockdown was performed to evaluate the integrin influence on chemotaxis and adhesion. Amygdalin significantly reduced chemotactic activity, migration, and adhesion of DU-145 but not of PC3 cells. Amygdalin elevated integrin α2 in both cell lines. Integrin α6 was reduced by amygdalin only in DU-145 cells, whereas ß1 increased only in PC3 cells. Functional blocking revealed a negative association of α2 with PC3 and DU-145 chemotaxis. The ß1 increase correlated with enhanced chemotaxis, the diminished α6 expression with reduced chemotaxis. Amygdalin acted on prostate cancer cells in vitro. It induced downregulation of α6 integrin in DU-145 but not in PC3 cells, suggesting that exposing certain prostate cancer cells to amygdalin might inhibit metastatic spread promoted by this particular integrin.

Euryops arabicus displays anti-inflammatory activities in experimental models.

ETHNOPHARMACOLOGICAL RELEVANCE: Euryops arabicus (Asteraceae) is grown in Arab Peninsula. Its aerial parts possess ethnomedicinal applications against several inflammatory conditions. AIM OF THE STUDY: To evaluate the anti-inflammatory activity of Euryops arabicus (E. arabicus) organic extract as well as its major polymethoxylated flavonoids. MATERIALS AND METHODS: Acute toxicity of the total extract of E. ararbicus was evaluated by assessing LD50. In vivo anti-inflammatory activity was evaluated in rats injected with carrageenan in the plantar area. Paw edema volume, histological changes and rats'stair climbing and motility were assessed. In vitro anti-inflammatory activity of the isolated compounds was evaluated in peripheral blood mononuclear cells (PBMCs) challenged with carrageenan. Inflammation markers were assessed in cellular lysates and collected media. RESULTS: The extract was found safe and considered unclassified with an oral LD50 > 2000 mg/kg in rats. Pretreatment of rats with a total extract of E. arabicus at doses of 100 and 250 mg/kg significantly inhibited carrageenan-induced increase in paw edema volume and histopathological changes. Also, it significantly ameliorated diminution of climbing and motility. Phytochemical studies led to the isolation and identification of five polymethoxylated flavonoids. The anti-inflammatory properties of the isolated compounds were evaluated in carrageenan-challenged peripheral blood mononuclear cells (PBMCs). All compounds exhibited appreciable antioxidant activities. Further, pre-incubation of the cells with the isolated metabolites significantly ameliorated the rise in cyclo-oxygenase-2 (COX-2), inducible nitric oxide synthase (iNOS) and monocyte chemoattractant protein-1 (MCP-1) induced by carrageenan challenge. Further, the compounds inhibited the leakage of interleukin-1ß (IL-1ß), interleukin-6 (IL-6) and myeloperoxidase (MPO) in media collected from stimulated cells. CONCLUSION: E. arabicus exhibited in vivo anti-inflammatory effects in the carrageenan model as it ameliorated rat paw edema, histopathological changes and movement dysfunction. in vitro activity of isolated compounds was confirmed in stimulated PBMCs. Thus, the anti-inflammatory activity of E. arabicus can be attributed, at least partly, to its anti-oxidant, anti-inflammatory and anti-chemotactic properties.

Standardized ethanol extract, essential oil and zerumbone of Zingiber zerumbet rhizome suppress phagocytic activity of human neutrophils.

BACKGROUND: Zingiber zerumbet rhizome and its bioactive metabolites have previously been reported to exhibit innumerable pharmacological properties particularly anti-inflammatory activities. In the present study, the 80% ethanol extract, essential oil and zerumbone of Z. zerumbet rhizomes were explored for their in vitro immunosuppressive properties on chemotaxis, CD11b/CD18 expression, phagocytosis and chemiluminescence of isolated human polymorphonuclear neutrophils (PMNs). METHODS: The extract was analyzed quantitatively by performing a validated reversed phase high performance liquid chromatography (RP-HPLC). Zerumbone was isolated by chromatographic technique while the essential oil was acquired through hydro-distillation of the rhizomes and further analyzed by gas chromatography (GC) and GC-MS. Chemotaxis assay was assessed by using a 24-well cell migration assay kit, while CD18 integrin expression and phagocytic engulfment were measured using flow cytometry. The reactive oxygen species (ROS) production was evaluated by applying lucigenin- and luminol-enhanced chemiluminescence assays. RESULTS: Zerumbone was found to be the most abundant compound in the extract (242.73 mg/g) and the oil (58.44%). Among the samples tested, the oil revealed the highest inhibition on cell migration with an IC50 value of 3.24 µg/mL. The extract, oil and zerumbone showed moderate inhibition of CD18 integrin expression in a dose-dependent trend. Z. zerumbet extract showed the highest inhibitory effect on phagocytic engulfment with percentage of phagocytizing cells of 55.43% for PMN. Zerumbone exhibited strong inhibitory activity on oxidative burst of zymosan- and PMA-stimulated neutrophils. Zerumbone remarkably inhibited extracellular ROS production in PMNs with an IC50 value of 17.36 µM which was comparable to that of aspirin. CONCLUSION: The strong inhibition on the phagocytosis of neutrophils by Z. zerumbet extract and its essential oil might be due the presence of its chemical components particularly zerumbone which was capable of impeding phagocytosis at different stages.

Selective Adhesion and Directional Migration of Endothelial Cells Guided by Cys-Ala-Gly Peptide Density Gradient on Antifouling Polymer Brushes.

Selective adhesion and directional migration of endothelial cells (ECs) on biomaterials is critical to realize the rapid endothelialization. In this study, a Cys-Ala-Gly (CAG) peptide density gradient is generated on homogeneous cell-resisting poly(2-hydroxyethyl methacrylate-co-glycidyl methacrylate) brushes by immersing the brushes in a complementary gradient solution of CAG and competitive mercapto-terminated methoxyl poly(ethylene glycol). The adhesion and spreading of smooth muscle cells (SMCs) is impaired effectively on the gradient surface. About six folds of adherent ECs over SMCs are achieved at the position (10 mm) of highest CAG density on the gradient surface in a co-culture condition. Due to the gradient cues, ECs migrate fastest with the best directionality of 86.7% at the middle of the gradient, leading to the maximum net displacement as well.

Gastrodin protects dopaminergic neurons via insulin-like pathway in a Parkinson's disease model.

BACKGROUND: Recently, the use of traditional Chinese medicine (TCM) has become more generally accepted, including by the Food and Drug Administration. To expand the use of TCM worldwide, it is important to study the molecular mechanisms by which TCM and its active ingredients produce effects. Gastrodin is an active ingredient from Gastrodia elata Blume. It is reported that gastrodin has neuroprotective function in Parkinson's disease. But its mechanisms of neuroprotection remain not clear in PD. Here, we build two C. elegans PD model using 6-OHDA and transgenic animal to observe the changes of PD worms treated with or without gastrodin to confirm the function of gastrodin, then utilize mutant worms to investigate DAF-2/DAF-16 signaling pathway, and finally verify the mechanism of gastrodin in PD. RESULTS: Gastrodin attenuates the accumulation of α-synuclein and the injury of dopaminergic neurons, improves chemotaxis behavior in Parkinson's disease models, then recovers chemotaxis behavior by insulin-like pathway. DAF-2/DAF-16 is required for neuroprotective effect of dopamine neuron in PD. CONCLUSIONS: Our study demonstrated that gastrodin rescued dopaminergic neurons and reduced accumulation of α-synuclein protein, and the activity of gastrodin against Parkinson's disease depended on the insulin-like DAF-2/DAF-16 signaling pathway. Our findings revealed that this insulin-like pathway mediates neuroprotection of gastrodin in a Parkinson's disease model.

Innate positive chemotaxis to paeonal from highly attractive Chinese medicinal herbs in the cigarette beetle, Lasioderma serricorne.

Lasioderma serricorne, also known as cigarette beetle, can exploit a wide variety of stored materials as foods, but it is particularly common on tobacco and herbs. This beetle is a dominant pest species of stored Chinese medicinal materials (CMMs) causing high economic damages, making effective control strategies urgently needed. Behavioural manipulation is an important component of Integrated Pest Management. To the best of our knowledge, plant-borne volatile organic compounds (VOCs) have never been explored to develop lures for managing L. serricorne. In this study, the behavioural responses of L. serricorne to VOCs from four selected CMMs (Euphorbia kansui, Aconitum carmichaelii, Eucommia ulmoides and Pinellia ternata) were studied and their components analysed. Then, the olfactory responses of L. serricorne to the most abundant VOC identified in the preferred CMM, i.e., paeonal, was tested. L. serricorne showed significant differences in its preferences for the VOCs from the four CMMs, i.e, E. kansui > A. carmichaelii > E. ulmoides > P. ternata. From the VOCs of E. kansui, A. carmichaelii, E. ulmoides, and P. ternata, 77, 74, 56, and 81 molecules, were identified, respectively. Paeonal (23.5%), junipene (17.2%), hexanal (17.1%), and benzeneacetonitrile (14.0%) were the most abundant, respectively. Since paeonal dominated the VOC spectrum of the most preferred CMM, this compound was selected for further studies. L. serricorne showed significant positive responses to paeonal tested at various doses, with the most attractive ones being 100 µg and 500 µg. Our findings shed light on the olfactory cues routing the food searching behaviour in the cigarette beetle, providing important information on how L. serricorne targets particular CMMs. The high attractiveness of paeonal at low doses tested here may be exploited further to develop novel monitoring and control tools (e.g., lure-and-kill strategies) against this important stored product pest.

Leishmanicidal and antichemotactic activities of icetexanes from Salvia uliginosa Benth.

BACKGROUND: Several species of Salvia are used as medicinal plants around the world. Biological activities of isolated compounds have been described, being diterpenes frequently responsible for the effects. PURPOSE: Isolation of diterpenes from Salvia uliginosa Benth. and evaluation of the antichemotactic and leishmanicidal activities of the isolated compounds. STUDY DESIGN: To isolate diterpenes from S. uliginosa and evaluate their antichemotactic and leishmanicidal activities in vitro. METHODS: The exudate of S. uliginosa was obtained by rapidly dipping the aerial parts in dichloromethane. The compounds were isolated by repeated column chromatography over silica gel. The effects on L. amazonensis growth, survival, DNA degradation, ROS generation, as well as the antichemotactic activity and cytotoxicity of the compounds towards human erythrocytes and macrophages were evaluated. RESULTS: A novel icetexane diterpene, isoicetexone (IsoICT) along with the known diterpenes icetexone (ICT), and 7-acetoxy-6,7-dihydroicetexone were isolated from the dichloromethane surface exudate of S. uliginosa. The structures were elucidated using NMR and MS experiments, and by comparison with previously reported data. IsoICT and ICT at low concentrations caused completely inhibition of neutrophils migration in vitro. In addition, IsoICT and ICT showed high leishmanicidal activity against L. amazonensis, induced ROS production in parasites and presented low cytotoxicity against macrophages and human erythrocytes, and moderate to high selectivity index. CONCLUSION: These data indicated that IsoICT and ICT exhibit potent antichemotactic and leishmanicidal effects. Further studies are needed in order to evaluate the in vivo activities as well as the toxicity of the compounds.

A Dual Role of Amino Acids from Sesbania rostrata Seed Exudates in the Chemotaxis Response of Azorhizobium caulinodans ORS571.

Azorhizobium caulinodans ORS571 can induce nodule formation on the roots and the stems of its host legume, Sesbania rostrata. Plant exudates are essential in the dialogue between microbes and their host plant and, in particular, amino acids can play an important role in the chemotactic response of bacteria. Histidine, arginine, and aspartate, which are the three most abundant amino acids present in S. rostrata seed exudates, behave as chemoattractants toward A. caulinodans. A position-specific-iterated BLAST analysis of the methyl-accepting chemotaxis proteins (MCPs) (chemoreceptors) in the genome of A. caulinodans was performed. Among the 43 MCP homologs, two MCPs harboring a dCache domain were selected as possible cognate amino acid MCPs. After analysis of relative gene expression levels and construction of a gene-deleted mutant strain, one of them, AZC_0821 designed as TlpH, was confirmed to be responsible for the chemotactic response to the three amino acids. In addition, it was found that these three amino acids can also influence chemotaxis of A. caulinodans independently of the chemosensory receptors, by being involved in the increase of the expression level of several che and fla genes involved in the chemotaxis pathway and flagella synthesis. Thus, the contribution of amino acids present in seed exudates is directly related to the role as chemoattractants and indirectly related to the role in the regulation of expression of key genes involved in chemotaxis and motility. This "dual role" is likely to influence the formation of biofilms by A. caulinodans and the host root colonization properties of this bacterium.

Rumen microbial responses to supplemental nitrate. I. Yeast growth and protozoal chemotaxis in vitro as affected by nitrate and nitrite concentrations.

Nitrates have been fed to ruminants, including dairy cows, as an electron sink to mitigate CH4 emissions. In the NO3- reduction process, NO2- can accumulate, which could directly inhibit methanogens and some bacteria. However, little information is available on eukaryotic microbes in the rumen. Protozoa were hypothesized to enhance nitrate reductase but also have more circling swimming behavior, and the yeast Saccharomyces cerevisiae was hypothesized to lessen NO2- accumulation. In the first experiment, a culture of S. cerevisiae strain 1026 was evaluated under 3 growth phases: aerobic, anoxic, or transition to anoxic culture. Each phase was evaluated with a control or 1 of 3 isonitrogenous doses, including NO3-, NO2-, or NH4+ replacing peptone in the medium. Gas head phase, NO3-, or NH4+ did not influence culture growth, but increasing NO2- concentration increasingly inhibited yeast growth. In experiment 2, rumen fluid was harvested and incubated for 3 h in 2 concentrations of NO3-, NO2-, or sodium nitroprusside before assessing chemotaxis of protozoa toward glucose or peptides. Increasing NO2- concentration decreased chemotaxis by isotrichids toward glucose or peptides and decreased chemotaxis by entodiniomorphids but only toward peptides. Live yeast culture was inhibited dose-responsively by NO2- and does not seem to be a viable mechanism to prevent NO2- accumulation in the rumen, whereas a role for protozoal nitrate reductase and NO2- influencing signal transduction requires further research.

Development of analytical method for the quality control of the fruit bark of Punica granatum L. (pomegranate) and antichemotatic activity of extract and rich fraction in punicalagins.

Pomegranate is of current interest owing to the existing potential for industrial uses of fruit peels. This includes its availability as a raw vegetable material, a byproduct that constitutes residue in the use of the species and is recognized as a functional product, and beneficial health properties, as will be demonstrated in the studies cited. Therefore, it is necessary to ensure its effectiveness and safety. Toward this end, the aim of this study was to develop and validate an analytical method for the separation and quantification of total punicalagin present in the bark of the fruit of Punica granatum by HPLC. Purity tests such as water determination and total ashes were also performed. The ability of the extract and enriched fraction of punicalagin to inhibit leukocyte migration in vitro was determined by the Boyden's chamber method. The developed HPLC method demonstrated good separation and quantification of the punicalagin α and ß anomers. The method is efficient and reliable, and can ultimately be used for the analysis of the extract of pomegranate. The crude extract and the fraction of punicalagins significantly inhibited leukocyte migration at concentrations of 1 and 10 µg/mL in relation to the negative control, indicating potential antichemotactic action.

Partial agonist activity of α1-adrenergic receptor antagonists for chemokine (C-X-C motif) receptor 4 and atypical chemokine receptor 3.

We observed in PRESTO-Tango ß-arrestin recruitment assays that the α1-adrenergic receptor (AR) antagonist prazosin activates chemokine (C-X-C motif) receptor (CXCR)4. This prompted us to further examine this unexpected pharmacological behavior. We screened a panel of 14 α1/2- and ß1/2/3-AR antagonists for CXCR4 and atypical chemokine receptor (ACKR)3 agonist activity in PRESTO-Tango assays against the cognate agonist CXCL12. We observed that multiple α1-AR antagonists activate CXCR4 (CXCL12 = prazosin = cyclazosin > doxazosin) and ACKR3 (CXCL12 = prazosin = cyclazosin > alfuzosin = doxazosin = phentolamine > terazosin = silodosin = tamsulosin). The two strongest CXCR4/ACKR3 activators, prazosin and cyclazosin, were selected for a more detailed evaluation. We found that the drugs dose-dependently activate both receptors in ß-arrestin recruitment assays, stimulate ERK1/2 phosphorylation in HEK293 cells overexpressing each receptor, and that their effects on CXCR4 could be inhibited with AMD3100. Both α1-AR antagonists induced significant chemical shift changes in the 1H-13C-heteronuclear single quantum correlation spectrum of CXCR4 and ACKR3 in membranes, suggesting receptor binding. Furthermore, prazosin and cyclazosin induced internalization of endogenous CXCR4/ACKR3 in human vascular smooth muscle cells (hVSMC). While these drugs did not in induce chemotaxis in hVSMC, they inhibited CXCL12-induced chemotaxis with high efficacy and potency (IC50: prazosin-4.5 nM, cyclazosin 11.6 pM). Our findings reveal unexpected pharmacological properties of prazosin, cyclazosin, and likely other α1-AR antagonists. The results of the present study imply that prazosin and cyclazosin are biased or partial CXCR4/ACKR3 agonists, which function as potent CXCL12 antagonists. Our findings could provide a mechanistic basis for previously observed anti-cancer properties of α1-AR antagonists and support the concept that prazosin could be re-purposed for the treatment of disease processes in which CXCR4 and ACKR3 are thought to play significant pathophysiological roles, such as cancer metastases or various autoimmune pathologies.

Flavonoids of Artocarpus heterophyllus Lam. heartwood inhibit the innate immune responses of human phagocytes.

OBJECTIVES: To investigate the effects of flavonoids isolated from Artocarpus heterophyllus. heartwood on chemotaxis, phagocytosis, reactive oxygen species (ROS) production and myeloperoxidase (MPO) activity of human phagocytes. METHODS: Chemotaxis was evaluated using a modified Boyden chamber and phagocytosis was determined by flowcytometer. Respiratory burst was investigated by luminol-based chemiluminescence assay while MPO activity was determined by colorimetric assay. KEY FINDINGS: Artocarpanone and artocarpin strongly inhibited all steps of phagocytosis. Artocarpanone and artocarpin showed strong chemotactic activity with IC50 values of 6.96 and 6.10 µm, respectively, which were lower than that of ibuprofen (7.37 µm). Artocarpanone was the most potent compound in inhibiting ROS production of polymorphonuclear leucocytes and monocytes with IC50 values comparable to those of aspirin. Artocarpin at 100 µg/ml inhibited phagocytosis of opsonized bacteria (28.3%). It also strongly inhibited MPO release with an IC50 value (23.3 µm) lower than that of indomethacin (69 µm). Structure-activity analysis indicated that the number of hydroxyl group, the presence of prenyl group and variation of C-2 and C-3 bonds might contribute towards their phagocytosis. CONCLUSIONS: Artocarpanone and artocarpin were able to suppress strongly the phagocytosis of human phagocytes at different steps and have potential to be developed into potent anti-inflammatory agents.