Nitric Oxide Production In Macrophages Research Articles

Curcuma longa L. extract increased immune responses in RAW 264.7 cells and cyclophosphamide-induced BALB/c mice

Curcuma longa L. extract (CLE) exerts various biological functions including antioxidant, anti-inflammation, anticancer, and antiallergenic effects. However, its immune-enhancing capacity remains unclear. Therefore, the immune-enhancing effect of CLE was investigated in RAW 264.7 cells and cyclophosphamide (CPP)-induced immunosuppression model. CLE upregulated nitric oxide (NO) and reactive oxygen species production and increased inducible nitric oxide synthase and cyclooxygenase-2 expression without affecting the RAW 264.7 cells viability. The results of quantitative real-time reverse transcription polymerase chain reaction and sandwich enzyme-linked immunosorbent assay showed that CLE increased the gene expression and protein levels of tumor necrosis factor-α, interleukin-6, and interleukin-1β in RAW 264.7 cells. Moreover, CLE upregulated p65, I kappa B kinase α/β, and I kappa B α (IκBα) phosphorylation and downregulated IκBα expression in RAW 264.7 cells. CLE also increased p65 translocation from the cytoplasmic to the nucleus in RAW 264.7 cells. The oral administration of CLE increased organ indexes (including the spleen and thymus) and NO production in peritoneal macrophages and improved natural killer cell activity in CPP-induced immunosuppression BALB/c mice. Overall, CLE could be a useful health functional food material that can improve innate immunity via macrophage activation.

Extracellular ATP- and adenosine-mediated purinergic signaling modulates inducible nitric oxide synthase (iNOS) gene expression, enzyme activity and nitric oxide production in common carp (Cyprinus carpio) head kidney macrophages

Inducible nitric oxide (NO) synthase (iNOS) is a key immune mediator for production of inflammatory mediator NO from l-arginine. Tight regulation of iNOS expression and enzyme activity is critical for proper NO productions under inflammation and infection conditions. However, the regulatory mechanism for iNOS expression and enzyme activity in fish remains largely unknown. Here, we show that extracellular ATP treatment significantly up-regulates iNOS gene expression and enzyme activity, and consequently leads to enhanced NO production in Cyprinus carpio head kidney macrophages (HKMs). We further show that the extracellular ATP-induced iNOS enzyme activity and NO production can be attenuated by pharmacological inhibition of the ATP-gated P2X4 and P2X7 receptors with their respective specific antagonists, but enhanced by overexpression of P2X4 and P2X7 receptors in grass carp ovary cells. In contrast, adenosine administration significantly reduces iNOS gene expression, enzyme activity and NO production in carp HKMs, and these inhibitory effects can be reversed by pharmacological inhibition of adenosine receptors with the antagonist XAC. Furthermore, LPS- and poly(I:C)-induced iNOS gene expression, enzyme activity, and NO production are significantly attenuated by blockade of P2X4 and P2X7 receptors with their respective specific antagonists in carp HKMs, while overexpression of P2X and P2X7 receptors results in enhanced iNOS gene expression, enzyme activity and NO production in LPS- and poly(I:C)-treated grass carp ovary cells. Taken together, we firstly report an opposite role of extracellular ATP/adenosine-mediated purinergic signaling in modulating iNOS-NO system activity in fish.

병풀주정추출분말의 항염증 효능 검색

Centella asiatica (C. asiatica) is currently widely used in wound healing and has recently been reported to have immune suppressive properties. This study investigated the anti-inflammatory effect with ethanol-extract of C. asiatica cultivated in a smart farm. Analysis of asiaticoside in C. asiatica extract was performed using high performance liquid chromatography (HPLC) and as a result, the asiaticoside content of C. asiatica extract was 23.17 mg/g. The effect of C. asiatica extract on the expression of inflammatory mediators, such as interleukin-1beta (IL-1β), IL-6 and tumor necrosis factor-alpha (TNF-α), and nitric oxide (NO) was examined in murine macrophage cell line, RAW264.7 using ELISA method. C. asiatica extract inhibited the production of NO, IL-1β, IL-6, and TNF-α in macrophages stimulated with lipopolysaccharide (LPS) at a dose dependent manner. C. asiatica extract also suppressed the expression of IL-6 and IL- 8 in HaCaT cells, a human keratinocytes, stimulated with TNF-α/IFN-. These results suggest that C. asiatica cultivated in a smart farm can be effectively utilized as a therapeutic agent for inflammatory disease.

Immunomodulatory effects of lotus seed (Nelumbo nucifera Gaertn.) peptides on macrophages in mice

Immunomodulatory effects of lotus seed (Nelumbo nucifera Gaertn.) peptides (LSPs) were studied in this paper. The LSPs were prepared by trypsin enzymatic hydrolysis and were separated by ultrafiltration separation technology. The following four peptide fractions with different molecular weight were obtained: LSP-I (>10 kDa), LSP-II (5–10 kDa), LSP-III (3–5 kDa), and LSP-IV (<3 kDa). Macrophage phagocytosis capacity, NO production and cytokine levels were measured in healthy and immunosuppressed mice to explore the effects of immunomodulatory activity of LSPs. In vitro, among the four peptides, LSP-IV showed the greatest effect on RAW264.7 macrophage phagocytosis. In vivo, LSP-IV had no significant effect on the levels of nitric oxide (NO), interleukin 6 (IL-6) and tumor necrosis factor (TNF-α) in healthy mice in a dose-dependent manner, but significantly increased the levels of NO, IL -6 and TNF-α secreted by peritoneal macrophages (p < 0.01 and p < 0.001, respectively) in immunosuppressed mice. In particular, high doses of LSP-IV (0.10 g/kg body weight) showed a stronger immunomodulatory potential. Our findings shed light on the potential of low-molecular-weight peptides from lotus seeds as novel natural immunoregulatory dietary factors.

Rapid synthesis of α(1,2)-d-mannans on the surface of Mycobacterium tuberculosis and their nitric oxide-inducing activities

The mannose cap motif, which consists of short-chain α(1,2)-d-mannans located on the non-reducing end of Mycobacterium tuberculosis’ mannose-capped lipoarabinomannan (ManLAM), exhibits strong binding affinities toward the lectins on mammalian host cells. The α(1,2)-d-mannans induce the immunosuppressive effects crucial for the survival and virulence of mycobacteria. However, the biological activities of discrete α(1,2)-d-mannans with different chain lengths remain unknown. In this study, the rapid synthesis of α(1,2)-d-mannans was rationally developed to increase the accessibility of α(1,2)-d-mannans. The rapid synthesis enabled simultaneous productions of the protected α(1,2)-d-mannans with chain lengths of 2–5 units, at room temperature (25 °C), within 4 h. After hydrolysis unmasking, different sizes of α(1,2)-d-mannans, and their α(1,6)-d-mannan counterparts were obtained and biologically evaluated. In summary, this work led to the optimally-designed low-steric-hindrance bicyclic orthoester monomer suitable for the gram-scale rapid synthesis of α(1,2)-d-mannans at 25 °C. This provided a basis for further development of more efficient syntheses for glycans with (1,2)-glycosidic linkages. Notably, the improved accessibility to these glycan motifs allowed us to discover that the α(1,2)-d-mannobioside could significantly enhance LPS-induced nitric oxide production in macrophages, suggesting its potential use as an immunomodulator and implying the existence of an unknown pathway or receptor responsible for this effect.

MEK inhibitors increase the mortality rate in mice with LPS-induced inflammation through IL-12-NO signaling

Lipopolysaccharide (LPS) is an endotoxin that can cause an acute inflammatory response. Nitric oxide (NO) is one of the most important innate immune system components and is synthesized by inducible NOS (iNOS) in macrophages in response to stimulation with LPS. LPS activates the RAS-RAF-mitogen-activated protein kinase/ERK kinase (MEK)-extracellular-signal-regulated kinase (ERK) signaling cascade in macrophages. The purpose of this study was to examine how the combination of LPS and MEK inhibitors, which have been used as anticancer agents in recent years, affects inflammation. We showed that MEK inhibitors enhanced iNOS expression and NO production in LPS-stimulated mouse bone marrow-derived macrophages. A MEK inhibitor increased the mortality rate in mice with LPS-induced inflammation. The expression of the cytokine interleukin-12 (IL-12) in macrophages was enhanced by the MEK inhibitor, as shown by a cytokine array and ELISA. IL-12 enhanced iNOS expression and NO production in response to LPS. We also showed that tumor necrosis factor (TNF-α) was secreted by macrophage after stimulation with LPS and that TNF-α and IL-12 synergistically induced iNOS expression and NO production. An anti-IL-12 neutralizing antibody prevented NO production and mortality in an LPS-induced inflammation mouse model in the presence of a MEK inhibitor. These results suggest that the MEK inhibitor increases the mortality rate in mice with LPS-induced inflammation through IL-12-NO signaling.

Origanum vulgare: peroxidase-, superoxide dismutase- and immunomodulatory activities on macrophages activated with Helicobacter pylori derivatives

Helicobacter pylori, invades the gastric mucosa and is one of the causative agents of stomach cancer and peptic ulcers. Origanum vulgare, is a flavouring herb used worldwide. But little is known about the effects of extracts prepared by maceration in cold PBS. This study was aimed at determining the superoxide dismutase (SOD)- and peroxidase (Px)-like antioxidant activities as well as the immunomodulatory activity (anti-inflammatory/pro-inflammatory) of an aqueous extract of O. vulgare by evaluating the production of nitric oxide (NO) in macrophages stimulated with H. pylori derivatives. The cold extract presented SOD-like and Px-like activities with effective concentration 50 (EC50) values of Px = 489.7 ± 48 µg/ml and SOD= 384.7 ± 30 µg/ml. The extract was also capable of modulating the production of NO in macrophages stimulated by H. pylori derivatives by exerting a pro-inflammatory activity at high concentrations and an anti-inflammatory activity at low concentrations.

Synergistic Pulmonoprotective Effect of Natural Prolyl Oligopeptidase Inhibitors in In Vitro and In Vivo Models of Acute Respiratory Distress Syndrome.

Acute respiratory distress syndrome (ARDS) is a highly morbid inflammatory lung disease with limited pharmacological interventions. The present study aims to evaluate and compare the potential pulmonoprotective effects of natural prolyl oligopeptidase (POP) inhibitors namely rosmarinic acid (RA), chicoric acid (CA), epigallocatechin-3-gallate (EGCG) and gallic acid (GA), against lipopolysaccharide (LPS)-induced ARDS. Cell viability and expression of pro-inflammatory mediators were measured in RAW264.7 cells and in primary murine lung epithelial and bone marrow cells. Nitric oxide (NO) production was also assessed in unstimulated and LPS-stimulated RAW264.7 cells. For subsequent in vivo experiments, the two natural products (NPs) with the most favorable effects, RA and GA, were selected. Protein, cell content and lipid peroxidation levels in bronchoalveolar lavage fluid (BALF), as well as histopathological changes and respiratory parameters were evaluated in LPS-challenged mice. Expression of key mediators involved in ARDS pathophysiology was detected by Western blotting. RA and GA favorably reduced gene expression of pro-inflammatory mediators in vitro, while GA decreased NO production in macrophages. In LPS-challenged mice, RA and GA co-administration improved respiratory parameters, reduced cell and protein content and malondialdehyde (MDA) levels in BALF, decreased vascular cell adhesion molecule-1 (VCAM-1) and the inducible nitric oxide synthase (iNOS) protein expression, activated anti-apoptotic mechanisms and down-regulated POP in the lung. Conclusively, these synergistic pulmonoprotective effects of RA and GA co-administration could render them a promising prophylactic/therapeutic pharmacological intervention against ARDS.

Studies of the Impact of the Bifidobacterium Species on Inducible Nitric Oxide Synthase Expression and Nitric Oxide Production in Murine Macrophages of the BMDM Cell Line.

Bifidobacterium species are one of the most important probiotic microorganisms which are present in both, infants and adults. Nowadays, growing data describing their healthy properties arise, indicating they could act at the cellular and molecular level. However, still little is known about the specific mechanisms promoting their beneficial effects. Nitric oxide (NO), produced by inducible nitric oxide synthase (iNOS), is involved in the protective mechanisms in the gastrointestinal tract, where it can be provided by epithelial cells, macrophages, or bacteria. The present study explored whether induction of iNOS-dependent NO synthesis in macrophages stems from the cellular action of Bifidobacterium species. The ability of ten Bifidobacterium strains belonging to 3 different species (Bifidobacterium longum, Bifidobacterium adolescentis, and Bifidobacterium animalis) to activate MAP kinases, NF-κB factor, and iNOS expression in a murine bone-marrow-derived macrophages cell line was determined by Western blotting. Changes in NO production were determined by the Griess reaction. It was performed that the Bifidobacterium strains were able to induce NF-қB-dependent iNOS expression and NO production; however, the efficacy depends on the strain. The highest stimulatory activity was observed for Bifidobacterium animalis subsp. animals CCDM 366, whereas the lowest was noted for strains Bifidobacterium adolescentis CCDM 371 and Bifidobacterium longum subsp. longum CCDM 372. Both TLR2 and TLR4 receptors are involved in Bifidobacterium-induced macrophage activation and NO production. We showed that the impact of Bifidobacterium on the regulation of iNOS expression is determined by MAPK kinase activity. Using pharmaceutical inhibitors of ERK 1/2 and JNK, we confirmed that Bifidobacterium strains can activate these kinases to control iNOS mRNA expression. Concluding, the induction of iNOS and NO production may be involved in the protective mechanism of action observed for Bifidobacterium in the intestine, and the efficacy is strain-dependent.

The effects of arginine and branched-chain amino acid supplementation to reduced-protein diet on intestinal health, cecal short-chain fatty acid profiles, and immune response in broiler chickens challenged with Eimeria spp.

We investigated the effects of supplementing arginine (Arg) and branched-chain amino acids (BCAA) in broilers fed reduced-protein diets and challenged with Eimeria spp. All birds were fed the same starter diet meeting Cobb 500 nutrient specifications from d 1 to 9. Four grower diets: positive control (PC) with 20.0% crude protein (CP); reduced-protein negative control (NC) with 17.5% CP; or NC supplemented with Arg or BCAA at 50% above recommendations (ARG or BCAA) were fed to the birds from d 9 to 28. Birds were allocated in a 2×4 factorial arrangement (4 diets, each with or without challenge), with 8 replicates per treatment. On d 14, the challenge groups were orally gavaged with mixed Eimeria spp. Intestinal permeability was higher (P < 0.05) in NC than PC, whereas the permeability of ARG and BCAA groups did not differ significantly from PC. On d 28, a significant interaction (P < 0.01) was observed in CD8+: CD4+ ratios in cecal tonsils (CT), Eimeria challenge increased the ratios in all groups except for the ARG group. On d 21, a significant interaction was found for CD4+CD25+ percentages in CT (P < 0.01) that Eimeria challenge increased the percentages only in PC and NC groups. On d 21 and 28, significant interactions (P < 0.01) were found for macrophage nitric oxide (NO) production. In nonchallenged birds, NO was higher in the ARG group than other groups, but in challenged birds, NO was higher in both ARG and BCAA groups. On d 21, a significant interaction was found for bile anticoccidial IgA concentrations (P < 0.05) that Eimeria challenge increased IgA only in NC and ARG groups. The results suggest that a reduced-protein diet exacerbates the impact of the Eimeria challenge on intestinal integrity, but this could be mitigated by Arg and BCAA supplementations. Arginine and BCAA supplementations in reduced-protein diets could be beneficial for broilers against Eimeria infection by enhancing the immune responses. The beneficial effects of Arg supplementation tended to be more pronounced compared to BCAA supplementation.

Putrescine supplementation shifts macrophage L-arginine metabolism related-genes reducing Leishmania amazonensis infection.

Leishmania is a protozoan that causes leishmaniasis, a neglected tropical disease with clinical manifestations classified as cutaneous, mucocutaneous, and visceral leishmaniasis. In the infection context, the parasite can modulate macrophage gene expression affecting the microbicidal activity and immune response. The metabolism of L-arginine into polyamines putrescine, spermidine, and spermine reduces nitric oxide (NO) production, favoring Leishmania survival. Here, we investigate the effect of supplementation with L-arginine and polyamines in infection of murine BALB/c macrophages by L. amazonensis and in the transcriptional regulation of genes involved in arginine metabolism and proinflammatory response. We showed a reduction in the percentage of infected macrophages upon putrescine supplementation compared to L-arginine, spermidine, and spermine supplementation. Unexpectedly, deprivation of L-arginine increased nitric oxide synthase (Nos2) gene expression without changes in NO production. Putrescine supplementation increased transcript levels of polyamine metabolism-related genes Arg2, ornithine decarboxylase (Odc1), Spermidine synthase (SpdS), and Spermine synthase (SpmS), but reduced Arg1 in L. amazonensis infected macrophages, while spermidine and spermine promoted opposite effects. Putrescine increased Nos2 expression without leading to NO production, while L-arginine plus spermine led to NO production in uninfected macrophages, suggesting that polyamines can induce NO production. Besides, L-arginine supplementation reduced Il-1b during infection, and L-arginine or L-arginine plus putrescine increased Mcp1 at 24h of infection, suggesting that polyamines availability can interfere with cytokine/chemokine production. Our data showed that putrescine shifts L-arginine-metabolism related-genes on BALB/c macrophages and affects infection by L. amazonensis.

Comparative study of potent anti-amoebic and anti-inflammatory activities of different extracts from Sida rhombifolia (L)

Background: Sida rhombifolia (L) is a medicinal plant from tropical regions belonging to the Malvaceae family and the plantea kingdom. It is known for its multiple pharmacological properties. The aim of this work was to evaluate the anti-amoebic, and anti-inflammatory potential of Sida rhombifolia aqueous and ethanolic leaf and stem extracts harvested in two localities of Cameroon (Yaoundé and Massangam in the Centre and West regions, respectively). Methods: The anti-amoebic activity was evaluated on a polyxenic culture of Entamoeba histolytica. A primary macrophage culture activated by Saccharomyces cereviseae (SC) was used to evaluate anti-inflammatory potential of the plant extracts. Macrophages were treated with different concentrations (1; 10; 100 and 500 μg/mL) of the extracts for the inhibition of nitric oxide (NO) production and 5-lipoxygenase activity. Methods: The anti-amoebic activity was evaluated on a polyxenic culture of Entamoeba histolytica. A primary macrophage culture activated by Saccharomyces cereviseae (SC) was used to evaluate the anti-inflammatory potential of the plant extracts. Macrophages were treated with different concentrations (1; 10; 100 and 500 μg/mL) of the extracts for the inhibition of nitric oxide (NO) production and 5-lipoxygenase activity. Results: No significant difference was found between the anti-amoebic activity of the ethanolic extract of Yaoundé (Centre region, IC50 = 7.71 μg/mL) and that of ethanolic leaf extract from Massagam (West region IC50 = 7.77 μg/mL) after 72 hours. Among the extracts, ethanolic leaf extracts exhibited the highest anti-amoebic activity after 72 hours of treatment. Metronidazole showed better activity (IC50 = 5.96 µg/mL) in the same periods of time. Phenolic compounds and flavonoid contents were higher in Yaoundé (Centre region) ethanolic leaf extract, proving that these extracts can prevent certain damages linked to a state of oxidative stress. The ethanolic extracts of the leaves significantly inhibited NO production and 5-lipoxygenase activity in macrophages (IC50 of 3.85 µg/mL; 3.99 µg/mL and 36.64 µg/mL; 73.22 µg/mL respectively). Conclusion: This preliminary study shows that the ethanolic extract of S. rhombifolia possesses better anti-amoebic properties and can act at the level of the intestinal mucosa in order to fight against the damage linked to the dysfunction of the inflammatory cells.

Semi-Synthesis of Flavonoid Glycosides and Their Anti-Inflammatory and Antitumor Activities towards Triple Negative Breast Cancer.

Flavonoid glycosides are known to possess diverse bioactivities including antitumor and anti-inflammatory properties. Hesperetin is abundant in nature and can be used to synthesize bioactive flavonoids. This has the advantages of low cost, short synthetic steps, simple operation, and good yields. In this study, we aimed to synthesize bioactive flavonoids and flavonoid glycosides from hesperetin and evaluate the antitumor and anti-inflammatory activities of these compounds. A series of flavonoids and their derivatives were synthesized by methoxylation, oxidative dehydrogenation, benzylation, debenzylation, and deacetylation as well as using a modified peroxyacetone method and a glycoside condensation reaction. Their anti-inflammatory activities were evaluated for their inhibitory effects on nitric oxide (NO), tumor necrosis factor (TNF-α), and interleukin-6 (IL-6) production in LPS-induced RAW264.7 mouse macrophages. Their structures were characterized by HRMS, 1 H-NMR, and 13 C-NMR, and their cytotoxicity on the human triple-negative breast cancer cell (TNBC) line, SUM 149, was tested by using the MST assay. Most of the compounds markedly reduced NO production in LPS-stimulated murine macrophages at the tested concentrations in a dose-dependent manner. Among these, compounds 1, 7, 9, and 17 showed significant anti-inflammatory activities against NO production in LPS-induced RAW264.7 mouse macrophages. In addition, they could also reduce the release of TNF-α and IL-6 in a concentration-dependent manner. Most of the tested compounds showed remarkable anti-human TNBC activities. Compounds 1b-1m, 1, and 3 showed a certain degree of growth inhibition effect on the human TNBC cell lines and their IC50 values were all below 16.61 μM. In addition, compound 1l was the most cytotoxic with IC50 values of 1.38±0.31 μM, while the other compounds were inactive with inhibition rates <50 % at the highest concentration tested (20 μM). A novel series of flavonoids were synthesized from the natural flavonoid, hesperetin, including 17 new compounds. Screening tests indicated that most of these compounds reduced NO production in LPS-stimulated murine macrophages at concentrations of 15 to 60 μM, and the inhibition generally increased in a dose-dependent manner. Some compounds showed different degrees of cytotoxicity on the human TBNC cell lines, SUM 149.

Leishmania infantum NTPDase1 and NTPDase2 play an important role in infection and nitric oxide production in macrophages

Leishmania infantum, the causative agent of American Visceral Leishmaniasis (VL), is known for its ability to modulate the host immune response to its own favor. Ecto-nucleoside triphosphate diphosphohydrolase (ENTPDase) represents a family of enzymes that hydrolyze nucleotides and are involved in nucleotide-dependent biological processes. L. infantum has two ENTPDases, namely LiNTPDase1 and LiNTPDase2. Here, we used genetic tools to overexpress or abolish the expression of LiNTPDase1 and -2 to assess their role in parasite growth in culture and macrophage infection. While LiNTPDase1 or 2-overexpressing clones showed no morphological or growth changes in promastigotes, LiNTPDase2 overexpression increased macrophage adhesion and infection by 50% and 30%, respectively. The individual LiNTPDase1 and 2 knockout mutants showed lag in growth profile, which was reversed by the addition of adenine and guanine to the culture media. Moreover, the morphology of the knockout mutants even in supplemented media was changed to an amastigote-like form. The double knockout of both genes was lethal and a mechanism of compensation of deletion of one isoform was detected in these mutants. Correspondingly, the absence of LiNTPDase1 or LiNTPDase2 led to a dramatic reduction in in vitro infection (∼90%). Interestingly, nitric oxide production was decreased in both knockout mutants during infection, which suggests that both LiNTPDases can inhibit macrophage responses against the parasite. Overall, our results show important roles of LiNTPDase1 and -2 concerning in vitro macrophage infection and reinforce their use as potential targets to control Leishmania infections.

Discovery of fusidic acid derivatives as novel STING inhibitors for treatment of sepsis

Sepsis is often caused by systemic inflammatory responses. Stimulator of interferon genes (STING) could be a promising treatment target for sepsis. In this study, we report the design and synthesis of a new series of fusidic acid derivatives. Among the synthesized derivatives, the promising compound 30 inhibited lipopolysaccharide (LPS)-induced nitric oxide production in macrophages with an IC50 of 1.15 μM. Compound 30 was then identified as a STING inhibitor that suppressed LPS-induced inflammatory responses and inhibited the abnormal activation of the TBK1, IRF3, and NF-κB signaling pathways by targeting STING. In vivo treatment with compound 30 significantly inhibited the inflammatory response and ameliorated the histopathological changes of the liver, and the mechanism of its anti-inflammatory effect in vivo was the same as that in vitro. Our studies identified compound 30 as a potent STING inhibitor, laying the groundwork for future drug development of anti-inflammatory agents for the treatment of sepsis.

Inhibitory Effect on Nitric Oxide Release in LPS-Stimulated Macrophages and Free Radical Scavenging Activity of Croton linearis Jacq. Leaves.

Oxidative stress is an important component of many diseases including cancer, along with inflammatory and neurodegenerative processes. Natural antioxidants have emerged as promising substances to protect the human body against reactive oxygen and nitrogen species. The present study evaluates the inhibition of nitric oxide (NO) production in LPS-stimulated RAW 264.7 murine macrophages and the free radical scavenging activity of Croton linearis Jacq. leaves. UPLC-QTOF-MS analysis identified 18 compounds: nine alkaloids with a morphinane, benzylisoquinoline or aporphine nucleus, and nine O-glycosylated-flavonoids with quercetin, kaempferol and isorhamnetin as the aglycones. The crude extract (IC50 21.59 µg/mL) and the n-hexane fraction (IC50 4.88 µg/mL) significantly reduced the NO production in LPS-stimulated macrophages but with relatively high cytotoxicity (CC50 75.30 and CC50 70.12 µg/mL, respectively), while the ethyl acetate fraction also showed good activity (IC50 40.03 µg/mL) without affecting the RAW 264.7 cell viability. On the other hand, the crude extract, as well as the dichloromethane and ethyl acetate fractions, showed better DPPH and ABTS free radical scavenging activities. Considering the chemical composition and the activity observed for Croton linearis leaves, they may be considered a good source of antioxidants to combat oxidative damage-related diseases.

Three new triterpenoid glycosides from Aronia melanocarpa (Michx.) Elliott

Three new triterpenoid glycosides, 2α,3α,23,24-tetrahydroxyurs-12,19- dien-oic acid 28-O-β- D -glucopyranoside (1), 2α,3β,23,24-tetrahydroxyurs-12, 19(29) -dien-28-oic acid 28-O-β- D -glucopyranoside (2), and 2α,3β,23,24-tetrahydroxyurs-12, 18-dien-28-oic acid 28-O-β- D -glucopyranoside (3) were isolated from Aronia melanocarpa (Michx.) Elliott. Their structures were elucidated by extensive spectroscopic methods. All the isolated compounds displayed moderate inhibitory activity against nitric oxide production in macrophages.

Thiazolidine derivatives: In vitro toxicity assessment against promastigote and amastigote forms of Leishmania infantum and ultrastructural study

Neglected diseases, such as Leishmaniasis, constitute a group of communicable diseases that occur mainly in tropical countries. Considered a public health problem with limited treatment. Therefore, there is a need for new therapies. In this sense, our proposal was to evaluate in vitro two series of thiazolidine compounds (7a-7e and 8a-8e) against Leishmania infantum. We performed in vitro evaluations through macrophage cytotoxicity assays (J774) and nitric oxide production, activity against promastigotes and amastigotes, as well as ultrastructural analyzes in promastigotes. In the evaluation of cytotoxicity, the thiazolidine compounds presented CC50 values between 8.52 and 126.83 μM. Regarding the evaluation against the promastigote forms, the IC50 values ranged between 0.42 and 142.43 μM. Compound 7a was the most promising, as it had the lowest IC50. The parasites treated with compound 7a showed several changes, such as cell body shrinkage, shortening and loss of the flagellum, intense mitochondrial edema and cytoplasmic vacuolization, leading the parasite to cell inviability. In assays against the amastigote forms, the compound showed a low IC50 (0.65 μM). These results indicate that compound 7a was efficient for both evolutionary forms of the parasite. In silico studies suggest that the compound has good oral bioavailability. These results show that compound 7a is a potential drug candidate for the treatment of Leishmaniasis.

Modulation of functional activity of heat-stressed chicken macrophages by poultry-derived probiotic lactobacilli

This study investigated the potential role of lactobacilli in mitigating the negative effects of heat stress on the functional activity of chicken macrophages. Macrophage-like MQ-NCSU cells were incubated at 40 and 44 °C in the presence or absence of a single or a mixture of different poultry-derived Lactobacillus spp., including Lactobacillus animalis, L. acidophilus, L. reuteri, and L. crispatus. Macrophage activation was evaluated by measuring nitric oxide (NO) production, phagocytic activity, and the transcription levels of cytokines, chemokine, and Toll-like receptors (TLRs). Macrophages exposed to heat stress exhibited increased production of NO, diminished expression of interleukin (IL)-1β and IL-12p40, and elevated expression of TLR2 and TLR4, whereas no significant alterations in the phagocytic activity of macrophages were observed. Conversely, treatment of macrophages with probiotic lactobacilli counteracted the effects associated with heat stress. This was evidenced by a notable enhancement in macrophage phagocytic activity, NO production and expression of IL-1β, IL-12p40, IL-18, and chemokine CXCL8, coupled with a reduction in TLR2 and TLR4 expression. These findings suggest that probiotic lactobacilli could be given to chickens to mitigate the negative effects of heat stress on their innate immune system. However, further studies are required to validate the observed effects in an in vivo model.

AK2 Antibacterial Synthetic Peptide Can Potentiate Macrophage Responses

Background: Emphasis on substitutional medications with the elevated bacterial resistance to current antibiotics is pivotal. We evaluated the antibacterial effect of AK2 by Minimum Bactericidal Concentration (MBC) and Minimum inhibitory Concentration (MIC) and its impact on macrophage responses in 17 strains of pathogenic bacteria. The gene expression of macrophage’s cytokines was evaluated. Accordingly, the bioinformatic assessment predicted this peptide’s physicochemical characteristics, behavior, and structures. The present study aimed to assess the antibacterial effect of AK2 peptides on Macrophage responses. Materials and Methods: Cytotoxicity level was assessed by MTT assay on the HeLa cell line. The hemolytic activity of peptides on red blood cells was evaluated. The Griess assay was performed to assess the amount of macrophage nitric oxide production. The real-time PCR method measured the iNOS, IFN-γ, and TNF-α gene expression in isolated macrophages. Results: Peptide concentrations (13-60 µg/mL) were observed as the MBC and MIC value results for various bacteria. No remarkable cytotoxicity was observed at 30 and 60 µg/ml concentrations after 24h. iNOS, IFN-γ, and TNF-α gene expression were upregulated. There was also a higher secretion of nitric oxide in 48 hour-culture of the cell line with peptide. Great antibacterial activity was observed in some bacterial strains, particularly B. melitensis. Conclusion: AK2 peptides display suitable antibacterial activity with negligible toxicity for host cells. This peptide could also stimulate macrophage responses through nitric oxide production and gene expression in proinflammatory cytokines.