SEARCH · PubMed Health

Results for “Complement C5a”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 505 records · Page 28Linked to original sources

PubMed1989

Differential sensitivities of purified human eosinophils and neutrophils to defined chemotaxins.

Functions of eosinophils and neutrophils isolated from normal human blood were determined by measuring chemotactic migration and release of beta-glucuronidase. Four well-characterized chemotaxins, the complement fragment C5a, formyl-methionyl-leucyl-phenylalanine (FMLP), platelet-activating factor (PAF), and leukotriene B4 (LTB4) were used as stimuli. Neutrophils showed remarkable chemotactic responses to all four chemotaxins. In contrast, eosinophils showed a significant chemotactic response to C5a and PAF, but only weak responses to FMLP and LTB4. Using these chemotaxins we found the following order of chemotactic potency (maximal number of migrated cells): C5a = LTB4 greater than FMLP greater than PAF for neutrophils and PAF = C5a greater than LTB4 = FMLP for eosinophils. Neutrophils elicited a significant beta-glucuronidase release when stimulated by C5a and FMLP, whereas only small amounts were released with PAF and LTB4. On the other hand, an amount of beta-glucuronidase released from eosinophils comparable to that from neutrophils was elicited only with C5a. FMLP, LTB4, and PAF caused the release of small percentages of beta-glucuronidase. The important cellular functions of eosinophils and neutrophils, chemotaxis and enzyme release, are thought to be controlled by differential responsiveness to stimuli.

Adult↗

PubMed1995

Conversion of murine Fabs isolated from a combinatorial phage display library to full length immunoglobulins.

The use of combinatorial Ig libraries displayed on the surface of bacteriophage has advantages over traditional hybridoma techniques for the generation of mAbs but in many instances full length Igs may be more desirable than Fab fragments. Two murine Fabs reactive with the human complement component C5a, recovered from a combinatorial library, were converted to full length IgG2a mAbs. The VH and VL domains of these antibodies were removed from the bacterial expression vector used for the combinatorial library construction, and subcloned into individual mammalian expression vectors containing the corresponding Ig heavy and light chain constant regions. The subcloning relied on 5' restriction endonuclease sites encoded by the oligonucleotide primers originally used to amplify the Ig cDNAs and 3' sites conserved in CH1 and C kappa. These vectors were co-transfected into COS cells yielding full length IgG2a versions of the anti-C5a antibodies. The mAbs, purified from the culture supernatant, retained the full activity of the Fabs, binding specifically to and neutralizing human recombinant C5a. Refined versions of the mammalian expression vectors have been constructed for single step conversion of murine recombinant Fabs, recovered from combinatorial libraries, to IgG2a mAbs.

Animals↗

PubMed1995

Interaction of neutrophils and endothelium in isolated coronary venules and arterioles.

This study reports measurements of porcine neutrophil dynamics in isolated microvessels. Porcine coronary venules and arterioles were isolated, cannulated, and perfused with fluorescently labeled neutrophils at a series of flow velocities. In venules (62.50 +/- 5.41 microns diam) under control conditions, rolling neutrophils were often observed at intraluminal flow velocities ranging from 600 to 6,000 microns/s, and the rolling fraction varied inversely as a function of flow velocity. There was no significant adherence under the control conditions at any of the various flow velocities. Pretreatment of the neutrophils with human recombinant complement 5a (C5a, 10(-8) M) increased adherence at low flow velocities but did not alter the rolling fraction. In contrast to venules, rolling neutrophils were not observed in arterioles (58.80 +/- 5.6 microns diam). Furthermore, neutrophils that were pretreated with C5a did not adhere to the arteriolar endothelium even at low flow velocities. We suggest that 1) isolated microvessels perfused with fluorescently labeled neutrophils are suitable models for the study of the interaction between neutrophils and the microvascular endothelium, 2) shear force plays an important role in neutrophil rolling in coronary venules but is not the major factor that prevents neutrophil rolling and adherence in arterioles, and 3) C5a causes neutrophil adherence in venules but not in arterioles, indicating that different mechanisms underlie the interaction between neutrophils and endothelium in venules and arterioles.

Animals↗

PubMed2005

Blockade of p38 map kinase inhibits complement-induced acute lung injury in a murine model.

Features of acute lung injury include neutrophil influx and increased vascular permeability with resultant pulmonary edema. Inhibition of p38 mitogen-activated protein kinase (MAPK) in in vivo models of endotoxin-induced inflammation results in reduction of organ injury as well as symptomatic relief. In this study, mice received an oral dose (100 mg/kg) of the p38 MAPK inhibitor, SB203580, followed by intratracheal instillation of an agent of complement origin, C5a des arg, at a concentration (10 microg) that induced acute lung injury. Neutrophil and protein content of bronchoalveolar lavage fluid as indicators of leukocyte influx and vascular permeability respectively were assessed. Animals that received C5a-instillation had a significant influx of neutrophils into the lungs (49+/-8%) while mice receiving C5a-instillation and prior treatment with SB203580 exhibited diminished influx (16+/-5%). Similarly, pretreatment with oral SB203580 resulted in decreased vascular permeability (241+/-34 microg/ml) than the positive control animals (407+/-135 microg/ml). Activity analysis of total lung p38 MAPK revealed that p38 activity was increased at 4 h after C5a-instillation and that SB203580-treated C5a-instilled mouse lungs had lower p38 activity than did the C5a-instilled control. These data indicate that oral administration of an agent inhibitory for p38 MAPK offers a protective effect in the lungs from both neutrophil influx and protein leak associated with acute lung injury.

Analysis of Variance↗

PubMedDate not supplied

Innate immune response to intramammary infection with Serratia marcescens and Streptococcus uberis.

Streptococcus uberis and Serratia marcescens are Gram-positive and Gram-negative bacteria, respectively, that induce clinical mastitis. Once initial host barrier systems have been breached by these pathogens, the innate immune system provides the next level of defense against these infectious agents. The innate immune response is characterized by the induction of pro-inflammatory cytokines, as well as increases in other accessory proteins that facilitate host recognition and elimination of the pathogens. The objective of the current study was to characterize the innate immune response during clinical mastitis elicited by these two important, yet less well-studied, Gram-positive and Gram-negative organisms. The pro-inflammatory cytokine response and changes in the levels of the innate immune accessory recognition proteins, soluble CD14 (sCD14) and lipopolysaccharide (LPS)-binding protein (LBP), were studied. Decreased milk output, induction of a febrile response, and increased acute phase synthesis of LBP were all characteristic of the systemic response to intramammary infection with either organism. Infection with either bacteria similarly resulted in increased milk levels of IL-1 beta, IL-8, IL-10, IL-12, IFN-gamma, TNF-alpha, sCD14, LBP, and the complement component, C5a. However, the duration of and/or maximal changes in the increased levels of these inflammatory markers were significantly different for several of the inflammatory parameters assayed. In particular, S. uberis infection was characterized by the sustained elevation of higher milk levels of IL-1 beta, IL-10, IL-12, IFN-gamma, and C5a, relative to S. marcescens infection. Together, these data demonstrate the variability of the innate immune response to two distinct mastitis pathogens.

Acute-Phase Proteins↗

PubMed1996

Recombinant human eotaxin induces oxygen radical production, Ca(2+)-mobilization, actin reorganization, and CD11b upregulation in human eosinophils via a pertussis toxin-sensitive heterotrimeric guanine nucleotide-binding protein.

The novel human CC-chemokine Eotaxin is a potent and selective chemotaxin for eosinophils. Here, the biological activities and the activation profile of Eotaxin were further characterized and compared with those of other eosinophil chemotaxins such as complement fragment C5a (C5a), platelet-activating factor (PAF), and RANTES in human eosinophils. Eotaxin stimulated the production of reactive oxygen metabolites as shown by lucigenin-dependent chemiluminescence and superoxide dismutase-inhibitable cytochrome C reduction. Furthermore, Eotaxin induced upregulation of the integrin CD11b. In addition, fluorescence measurements with Fura-2-labeled eosinophils in the presence of EGTA indicated Ca(2+)-mobilization from intracellular stores by Eotaxin. Flow cytometric studies showed rapid and translent actin polymerization on stimulation with Eotaxin. At optimal concentrations, the changes induced by Eotaxin were comparable with those obtained by C5a, PAF, and RANTES. Call responses elicited by Eotaxin were inhibited by pertussis toxin, indicating coupling of its putative receptor to heterotrimeric guanine nucleotide-binding proteins. These results indicate that Eotaxin is a strong activator of eosinophils with biological activity comparable with those of the eosinophil chemotaxins C5a, PAF, and RANTES. These findings point to a role of Eotaxin in the pathogenesis of eosinophilic inflammation as a chemotaxin as well as an activator of proinflammatory effector functions.

Actins↗

PubMedDate not supplied

Removal of anaphylatoxins C3a and C5a and chemokines interleukin 8 and RANTES by polyester white cell-reduction and plasma filters.

BACKGROUND: A few bedside polyester white cell (WBC)-reduction filters have been shown to scavenge C3a anaphylatoxin from stored blood components. One has been shown to remove the chemokines interleukin (IL)-8 and RANTES, but not the proinflammatory cytokines IL-1, IL-6, and tumor necrosis factor alpha. Removal by any filter of the anaphylatoxin C5a or the soluble membrane attack complex (SC5b-9) has not been studied. Further, the ability of other filters to scavenge these biologic response modifiers (BRM) is not known. Four WBC-reduction filters and one plasma filter were studied for their ability to remove IL-8, RANTES, IL-1 beta, C3a, C5a, and SC5b-9. STUDY DESIGN AND METHODS: Plasma was obtained either as freshly thawed fresh-frozen plasma, fresh-frozen plasma thawed and stored for 5 days, or platelet-poor supernatant. Cell-poor plasma was obtained and samples were taken before and after filtration through the various filters Levels of IL-1 beta, IL-8, RANTES, C3a, and SC5b9 were quantitated by enzyme immunoassay. To evaluate filter scavenging of C5a, an in vitro model was developed to generate high levels of C5a in plasma by activating plasma with zymosan. RESULTS: Levels of C3a, C5a, IL-8, and RANTES were reduced by filtration through two bedside platelet WBC-reduction filters, a plasma filter, and a prestorage red cell WBC-reduction filter, but not following filtration through a prestorage platelet WBC-reduction filter. For some BRMs and filters, however, evidence of filter saturation was seen. IL-1 beta was not removed by any of the filters tested. CONCLUSION: Some, but not all, bedside polyester filters and prestorage polyester filters can remove IL-8, RANTES, C3a, and C5a from units of plasma or platelets. Improved biomaterial engineering of these and other filters could maximize scavenging of BRMs and potentially diminish the adverse reactions associated with their infusion during transfusion.

Blood Component Removal↗

PubMed2001

Relationship between pancreatitis and lung diseases.

Patients with acute pancreatitis may develop acute lung injury, manifest clinically as the adult respiratory distress syndrome. Most patients who die during the early stages of severe acute pancreatitis die either with or as a result of this lung injury. To explore the events which couple acute pancreatitis to lung injury, a number of recent studies have been performed in the author's laboratory using a variety of experimental models and interventions including gene-targeted deletion of chemokines, cytokines, specific receptors, and adhesion molecules. These studies have indicated that adhesion molecules such as intracellular adhesion molecule-1 (ICAM-1), neutrophils, platelet activating factor (PAF), substance P, and chemokines acting via the CCR-1 chemokine receptor play a pro-inflammatory role while complement factor C5a plays an anti-inflammatory role in pancreatitis and lung injury. Future studies will build on these observations to expand the list of pro- and anti-inflammatory coupling factors and explore the mechanisms by which they act to cause or prevent lung injury in acute pancreatitis.

Acute Disease↗

PubMed1999

Diapedesis across mammary epithelium reduces phagocytic and oxidative burst of bovine neutrophils.

The effect of diapedesis on the phagocytic and oxidative burst activity of polymorphonuclear neutrophil (PMN) was examined, using an in vitro cell culture model consisting of a monolayer of primary mammary epithelial cells. Isolated blood PMN from 10 cows were added to the basal side of the epithelial cell monolayer. Diapedesis was induced by the addition of complement factor C5a to the apical side of the monolayer. PMN phagocytosis of Staphylococcus aureus and oxidative burst were measured before diapedesis on PMN that were non-activated and activated by incubation with C5a and on PMN after diapedesis, using flow cytometry. The percentages of PMN fluorescing due to phagocytosis of S. aureus and oxidative burst were reduced by 21.2 and 14.4%, respectively, after diapedesis. Pre-incubation in the presence of C5a had no effect on percentage PMN fluorescing due to phagocytosis or oxidative burst. The capacity for individual migrated PMN to phagocytose S. aureus and to produce an oxidative burst, as measured by the intensity of fluorescence, decreased by 34.2 and 30.3%. Activation of PMN with C5a increased intensity due to the oxidative burst, but had no effect on intensity due to phagocytosis. These data show that PMN diapedesis across mammary epithelium results in decreased phagocytosis and oxidative burst of the PMN.

Animals↗

PubMed2004

Stroma cell-derived factor 1alpha mediates desensitization of human neutrophil respiratory burst in synovial fluid from rheumatoid arthritic patients.

Classical chemoattractants such as fMLP or the complement factor C5a use G protein (Gi)-coupled receptors to stimulate both chemotaxis and production of reactive oxygen species (respiratory burst, RB) by polymorphonuclear leukocytes (PMN). The chemokine stroma cell-derived factor 1alpha (SDF1alpha) and its Gi-coupled receptor, CXCR4, regulate leukocyte trafficking and recruitment to the synovial fluid of rheumatoid arthritic patients (RA-SF). However, the role of SDF1alpha in the RB is unknown and was studied in this work in vitro with healthy PMN in the absence and presence of RA-SF. In healthy PMN, SDF1alpha failed to stimulate the RB, even though the p38 mitogen-activated protein kinase was activated to a similar level as in fMLP-stimulated PMN. In contrast, the SDF1alpha-mediated calcium transients and activation of phosphatidylinositol 3-kinase/Akt were partially deficient, while p44/42 mitogen-activated protein kinases were not activated. SDF1alpha actually desensitized weakly the fMLP-mediated RB of healthy PMN. This cross-inhibitory effect was amplified in PMN treated with RA-SF, providing a protection against the exacerbation of RB induced by C5a or fMLP. This SDF1alpha beneficial effect, which was prevented by the CXCR4 antagonist AMD3100, was associated with impairment of C5a- and fMLP-mediated early signaling events. Thus, although SDF1alpha promotes leukocyte emigration into rheumatoid synovium, our data suggest it cross-desensitizes the production of oxidant by primed PMN, a property that may be beneficial in the context of arthritis.

Arthritis, Rheumatoid↗

PubMed1994

Effect of a selective protein kinase C inhibitor, Ro 31-8425, on Mac-1 expression and adhesion of human neutrophils.

The role of protein kinase C (PKC) in mediating up-regulation of macrophage 1 adhesion protein (Mac-1) and adhesion of neutrophils in response to physiological agonists is not clear. Previous studies have relied on use of phorbol esters to activate PKC directly or on results obtained with non-selective inhibitors of protein kinases. 3-[8-(Aminomethyl)-6,7,8,9-tetrahydropyridol[1,2-a]-indol-10-yl]-4 -(1- methyl-3-indolyl)-1H-pyrrole-2,5-dione hydrochloride (Ro 31-8425) is a potent and highly selective inhibitor of PKC (Bit et al. J. Med. Chem. 1993. 36: 21). In these studies Ro 31-8425 has been used to define, more definitively, the role of PKC in mediating complement fragment C5a (C5a)-stimulated up-regulation of Mac-1 and adhesion of neutrophils to endothelial cells and to bovine serum albumin (BSA)-coated plastic. Phorbol 12, 13 dibutyrate (PBu2) increased surface expression of Mac-1 and stimulated adhesion of neutrophils to endothelial cells and to BSA-coated plastic. This confirms previous reports that activation of PKC can stimulate these responses. The PKC inhibitor, Ro 31-8425, inhibited the PBu2-stimulated responses, which confirms that Ro 31-8425 was effective in inhibiting PKC in these neutrophils. A more physiological agonist, C5a, also increased surface expression of Mac-1 and adhesion of neutrophils to endothelial cells and BSA-coated plastic. However, the responses to C5a were unaffected by Ro 31-8425. These results suggest that, although activation of PKC can promote up-regulation of Mac-1 and adhesion of neutrophils, this does not appear to be the physiological pathway. A non-selective protein kinase inhibitor, staurosporine, inhibited both PBu2 and C5a-stimulated adhesion. This suggests that a protein kinase other than PKC, possibly a tyrosine protein kinase, is likely to be involved in mediating C5a-stimulated Mac-1 up-regulation and adhesion. These results emphasise the need for caution in interpreting experiments and assuming a role for PKC. Use of a potent and selective inhibitor of PKC, Ro 31-8425, provides more definitive information.

Alkaloids↗

PubMed1991

Dibutyryl cyclic AMP induces formyl peptide receptor expression and chemotactic responses in a human eosinophilic cell line, EoL-1.

We investigated actin polymerization and the increase of cytosolic free calcium concentration ([Ca2+]i) in a human eosinophilic leukemia cell line, EoL-1, in response to stimulation with chemotactic factors; we also investigated the effect of dibutyryl cyclic AMP (dbcAMP) on the responses. EoL-1 cells under normal culture conditions did not show either actin polymerization or an increase in [Ca2+]i when stimulated with formyl-methionyl-leucyl-phenylalanine (fMLP). Expression of formyl peptide receptors was not detectable on untreated EoL-1 cells, either. Dibutyryl cAMP induced the expression of formyl peptide receptors and the responsiveness to fMLP. The responsiveness of EoL-1 cells to the complement fragment C5a and platelet-activating factor (PAF) was also induced or enhanced by dbcAMP. The growth of EoL-1 cells was decreased and the proportion of cells in the G0/G1 phase of the cell cycle was increased by the treatment of EoL-1 cells with dbcAMP. The proportion of eosinophilic granule-containing cells and the content of eosinophil cationic protein (ECP) in EoL-1 cells was also increased when they were stimulated with dbcAMP for a longer period. The responsiveness of EoL-1 cells to fMLP, C5a, and PAF was shown to be regulated independently. EoL-1 cells and dbcAMP seem to be useful for examining chemotactic receptor expression and its signal transduction mechanisms.

Actins↗

PubMed1989

Altered free cytosolic calcium changes and neutrophil chemotaxis in patients with juvenile periodontitis.

Nearly 70-75% of patients with localized juvenile periodontitis (JP) have abnormal polymorphonuclear leukocytic (PMN) chemotaxis. The objective of this study was to determine whether the lower chemotactic response in PMNs from JP patients is associated with a defect in intracellular signal transduction, as measured by stimulus-induced changes in free cytosolic calcium (Ca2+) mobilization. We report that peptide chemoattractants such as N-formyl-methionyl-leucyl-phenylalanine (fMLP) and the complement fragment C5a in direct comparative studies induced lower amounts of initial Ca2+ mobilization in PMNs from JP patients than healthy controls, as monitored by intracellular fura-2 fluorescence. The initial resting levels of free cytosolic Ca2+ in PMNs from JP patients and normal individuals were found to be similar. fMLP and C5a both mobilized Ca2+ in PMNs in a dose-dependent manner. Treatment of PMNs from 0.16 to 20 nM fMLP and 0.2 to 20 nM C5a resulted in elevated levels of free cytosolic Ca2+. However, above 20 nM fMLP and 5 nM C5a concentrations the extent of total Ca2+ mobilization did not differ significantly. Although fMLP and C5a caused Ca2+ mobilization in PMN cells from JP and healthy control subjects, fMLP stimulation induced higher levels of free cytosolic Ca2+ mobilization in PMN cells from healthy control subjects (141.29 +/- 25.55 nM/2 x 10(6) PMNs), than PMNs from JP patients (62.33 +/- 23.76 nM/2 x 10(6) PMNs). Similarly C5a induced higher levels of Ca2+ mobilization in PMNs from healthy control individuals (130.43 +/- 18.26 nM Ca2+/2 x 10(6) PMNs)O, when compared to JP patients (49.92 +/- 14.92 nM Ca2+/2 x 10(6) PMNs).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1983

Procoagulant activity of rabbit alveolar macrophages.

Alveolar macrophages are thought to participate in the clearance of fibrin from the injured lung, but their ability to facilitate the conversion of fibrinogen to fibrin (procoagulant activity) has not been described. In order to characterize their procoagulant properties, unstimulated alveolar macrophages obtained from normal rabbits were tested for their ability to accelerate the coagulation of plasma in a one-stage clotting assay. Compared with control assays containing no macrophages (coagulation times greater than 500 s), intact cells (10(6)/ml) were shown to display procoagulant activity (coagulation time, 153.6 +/- 11.3 s mean +/- SEM). Cell lysis caused further procoagulant activity to be expressed (125.6 +/- 11.8 s). Alveolar macrophages that were stimulated in vitro with bacterial lipopolysaccharide (LPS) or the purified complement fragments C5a and C5a des Arg caused further significant (p less than 0.002) reductions in coagulation times (intact cells, 71 to 76 s; lysed cells, 27 to 32 s), representing 5- to 6-fold and 30- to 40-fold increases in the procoagulant activity of intact and lysed cells, respectively. The generation of this material was independent of the presence of lymphocytes. The procoagulant material was identified as a cell-associated tissue thromboplastin, acting via the extrinsic coagulation pathway. These findings show that alveolar macrophages have procoagulant activity that is markedly augmented by LPS and complement fragments. This suggests that alveolar macrophages may contribute to intra-alveolar fibrin deposition in vivo.

Animals↗

PubMed2002

In vitro blood damage by high shear flow: human versus porcine blood.

Devices for modern heart support are minimized to reduce priming blood volume and contact area with foreign surfaces. Their flow fields are partly governed by very high velocity gradients. In order to investigate blood damage, porcine and human blood was passed through a narrow Couette type shear gap applying defined high shear rates within the typical range for devices such as blood pumps or artificial heart valves (gamma = 1800/s to 110,000/s for 400 ms). Traumatization profiles of both blood species were recorded in terms of hemolysis and platelet count. Sublethal damage in terms of platelet (PF4) and complement activation (C5a) was additionally measured for human blood. Results for porcine and human blood were very similar. Hemolysis was not started until critical shear rates of about 80,000/s. Impact on platelets was severe with drops in cell count of up to 65% (at gamma = 55,000/s to 110,000/s) likely to set stronger limits to the design layout of devices than hemolysis. Concentrations of PF4 and C5a clearly increased with shear rate exhibiting stronger gradients where hemolysis started. Due to the similar results of porcine and human blood for hemolysis and platelet drop, porcine blood seems to be suitable for device testing. Selection of blood species would thus depend on handling, availability and analysis demands.

Animals↗

PubMed2000

Opioids suppress chemokine-mediated migration of monkey neutrophils and monocytes - an instant response.

Opioid users having acquired human immunodeficiency syndrome (AIDS) are at a greater risk than non-users of contracting opportunistic infections. Opioid-administered and simian immunodeficiency virus (SIV)-infected rhesus monkeys have been an excellent model for studying AIDS and drug abuse in humans. In this study, chemotaxis of monkey leukocytes was evaluated using the chemokines interleukin-8 (IL-8) and regulated upon activation, normal T cell expressed (RANTES) as the chemoattractants, and the effects of various opioid agonists and antagonists on the efficiency of chemotaxis were examined. Opioids were either incubated with monkey leukocytes or added directly to chemokines, and the number of cells migrating toward IL-8 (for neutrophils) or RANTES (for monocytes) was scored. Inhibition of chemotaxis was seen with both assay conditions, and the inhibition was mediated by opioids binding to mu or kappa receptors. Binding to delta opiod receptors was rarely, if ever, observed. Although opioids themselves may act as weak chemoattractants for monkey leukocytes, addition of opioid agonists to chemokines would reduce the chemoattractant ability of the chemokines. Opioids did not cause the same inhibitory effect on the chemotactic migration of neutrophils when the complement component C5a or the chemotactic peptide N-formyl-MET-LEU-PHE (fMLP) was used as chemoattractant. These studies suggest that the presence of opioids during SIV infection immediately alters chemokine-mediated immune functions.

Animals↗

PubMed2004

Andrographolide acts through inhibition of ERK1/2 and Akt phosphorylation to suppress chemotactic migration.

We now evaluated the anti-inflammatory mechanisms of andrographolide on complement 5a (C5a)-induced macrophage recruitment in vitro. Andrographolide concentration dependently inhibited cell migration toward C5a with an IC50 of 5.6+/-0.7 microM. With relatively specific kinase inhibitors (PD98059, SB203580, SP600125, wortmannin and LY294002, respectively) the results showed that extracellular signal-regulated kinase1/2 (ERK1/2), p38 mitogen-activated protein kinase (p38 MAPK) and phosphatidylinositol-3-kinase (PI3K) were necessary for C5a-induced migration, whereas c-Jun N-terminal kinase (JNK) was nonessential. Andrographolide significantly attenuated C5a-stimulated phosphorylation of ERK1/2, and of its upstream activator, MAP kinase-ERK kinase (MEK1/2). C5a-activated ERK1/2 phosphorylation was 86+/-9% inhibited by 30 microM andrographolide. Under the same conditions, however, andrographolide failed to affect C5a-stimulated p38 MAPK and JNK phosphorylation. Andrographolide also strongly abolished C5a-stimulated Akt phosphorylation, a downstream target protein for PI3K. These results indicate that inhibition of cell migration by interfering with ERK1/2 and PI3K/Akt signal pathways may contribute to the anti-inflammatory activity of andrographolide.

Androstadienes↗

PubMed1993

Chemoattractant agents and nerve growth factor stimulate human spermatozoal reactive oxygen species generation.

OBJECTIVE: To investigate the ability of N-formyl-methionyl-leucyl-phenylalanine (f-MLP), complement 5a (C5a), and nerve growth factor (NGF) to stimulate human spermatozoal reactive oxygen species generation in fertile and infertile patients. DESIGN: Prospective, controlled study measuring human spermatozoal reactive oxygen species generation after addition of f-MLP, C5a, or NGF. SETTING: A large health maintenance organization. PATIENTS, PARTICIPANTS: The fertile group consisted of 14 men with established fertility and normal bulk semen parameters. The infertile group was comprised of 8 men who were infertile after > 18 months of unprotected sexual intercourse. INTERVENTIONS: The sperm samples were subjected to four test conditions: f-MLP stimulation, C5a stimulation, NGF stimulation, and no stimulation (control). MAIN OUTCOME MEASURE: Reactive oxygen generation was measured over a 15-minute period using the method of chemiluminescence. RESULTS: In both the fertile and infertile groups, reactive oxygen species generation was significantly enhanced by f-MLP, C5a, and NGF compared with controls. No significant difference in f-MLP- and C5a-stimulated reactive oxygen production was demonstrated between the infertile and fertile groups; however, there was a significant difference in reactive oxygen generation between infertile and fertile subjects when stimulated with NGF. CONCLUSIONS: The current study represents the first report of f-MLP-, C5a-, and NGF-stimulated reactive oxygen species generation by human spermatozoa. Nerve growth factor enhanced reactive oxygen species production to a greater extent in infertile subjects compared with fertile subjects. This points to a possible NGF-mediated biochemical defect in the sperm of infertile patients.

Adult↗