TLR7 ligand prevents allergen-induced airway hyperresponsiveness and eosinophilia in allergic asthma by a MYD88-dependent and MK2-independent pathway

Asthma is one of the leading causes of childhood hospitalization, and its incidence is on the rise throughout the world. Currently, the standard treatment for asthma is the use of corticosteroids to try to suppress the inflammatory reaction taking place in the bronchial tree. Using a murine model of atopic allergic asthma employing a methacholine-hyperresponsive (A/J) as well as a hyporesponsive (C57BL/6) strain of mice sensitized and challenged with ovalbumin, we show that treatment with a synthetic Toll-like receptor 7 (TLR7) ligand (S-28463, a member of the imidazoquinoline family) prevents development of the asthmatic phenotype. Treatment with S-28463 resulted in a reduction of airway resistance and elastance following ovalbumin sensitization and challenge. This was accompanied by a dramatic reduction in infiltration of leukocytes, especially eosinophils, into the lungs of both C57BL/6 and A/J mice following OVA challenge. Treatment with S-28463 also abolished both the elevation in serum IgE level as well as the induction of IL-4, IL-5, and IL-13 by OVA challenge. The protective effects of S-28463 were also observed in MK2 knockout, but not MYD88 knockout, mice. We did not observe a switch in cytokine profile from TH2 to TH1, as both IL-12p70 and IFN-γ levels were reduced following S-28463 treatment. These results clearly demonstrate the anti-inflammatory effect of imidazoquinolines in an allergic asthma model as well as the clinical potential of TLR7 ligands in the treatment of allergic diseases.

Synergistic epistasis and alternative hypotheses

Inbreeding generally results in deleterious shifts in mean fitness. If the fitness response to increasing inbreeding coefficient is non-linear, this suggests a contribution of epistasis to inbreeding depression. In a cross-breeding experiment, Salathe & Ebert (2003. J. Evol. Biol. 16: 976-985) tested and found the presence of this non-linearity in Daphnia magna. They argue that epistatic interactions cause this non-linearity. We argue here that their experimental protocol does not allow disentangling the effect of synergistic epistasis from two alternative hypotheses, namely hybrid vigour and statistical non-independence of data.

Batroxobin against anoxic damage of rat hippocampal neurons in culture: morphological changes and Hsp70 expression

Batroxobin, the thrombin-like enzyme, is used for therapeutic defibrination. We have found that batroxobin has good therapeutic effect in ischemic reperfusion rats and clinical practices in vivo. But we have not studied the neuroprotective effect of batroxobin on anoxic hippocampal neurons in vitro. The purpose of this study was to obtain further information on the mechanism of the batroxobin-induced neuroprotection and examine the neuroprotective effect on neurons exposed to anoxia. The effect of batroxobin on anoxic damages in cultured hippocampal neurons of neonatal rats was investigated by using morphological changes and heat shock protein 70 Kd (Hsp70) immunoreactive expression as indicators. The results indicate that batroxobin, besides its defibrination, may have a direct neuroprotective effect on anoxic damage of hippocampal neurons.

The role of MyD88 and TLR4 in the LPS-mimetic activity of Taxol

Taxol can mimic bacterial lipopolysaccharide (LPS) by activating mouse macrophages in a cell cycle-independent, LPS antagonist-inhibitable manner. Macrophages from C3H/HeJ mice, which have a spontaneous mutation in Toll-like receptor 4 (TLR4), are hyporesponsive to both LPS and Taxol, suggesting that LPS and Taxol may share a signaling pathway involving TLR4. To determine whether TLR4 and its interacting adaptor molecule MyD88 are necessary for Taxol's LPS mimetic actions, we examined Taxol responses of primary macrophages from genetically defective mice lacking either TLR4 (C57BL/10ScNCr) or MyD88 (MyD88 knockout). When stimulated with Taxol, macrophages from wild-type mice responded robustly by secreting both TNF and NO, while macrophages from either TLR4-deficient C57BL/10ScNCr mice or MyD88 knockout mice produced only minimal amounts of TNF and NO. Taxol-induced NF-kappa B-driven luciferase activity was reduced after transfection of RAW 264.7 macrophages with a dominant negative version of mouse MyD88. Taxol-induced microtubule-associated protein kinase (MAPK) activation and NF-kappa B nuclear translocation were absent from TLR4-null macrophages, but were preserved in MyD88 knockout macrophages with a slight delay in kinetics. Neither Taxol-induced NF-kappa B activation, nor I kappa B degradation was affected by the presence of phosphatidylinositol 3-kinase inhibitors. These results suggest that Taxol and LPS not only share a TLR4/MyD88-dependent pathway in generating inflammatory mediators, but also share a TLR4-dependent/MyD88-independent pathway leading to activation of MAPK and NF-kappa B.

Biological control of leachate from municipal landfills

Landfilling is still a popular way for municipal solid waste (MSW) treatment. Leachate generated from landfills is becoming a great threat to the surroundings as it contains high concentrations of toxic substances. How to control leachate migration and to protect environmental pollution is now a concern for many environmentalists. In this work, eight effective microorganisms (EMs) were isolated from wastewater, sludge and soil samples by enrichment culturing techniques and used for leachate migration control in columns and pilot experiments. The preliminary experiments reveal that the EMs could remove 25% and 40% of chemical oxygen demand (COD) from leachate in fine sand and sabulous clay columns, respectively. An aquifer system was designed to simulate in-situ control for leachate migration with EMs. The EMs were injected into the simulated aquifer and formed a permeable biological barrier. The experimental results show that the barrier removed 95% of COD and approximately 100% inorganic nitrogen, that is, nitrate-N plus nitrite-N plus ammonia-N, from the migrating leachate. CO2 production, redox potential and microbial number were monitored simultaneously in the aquifer during the experiment to assess the EMs' activities and the effect of the bio-barrier. The data indicate that the EMs isolated in this work had high activities and were effective for organic and nitrogenous contaminant removal throughout the experiment.

[The pathology and DNA quantitative study of renal clear cell carcinoma in children]

OBJECTIVE

To investigate the pathological features of renal clear cell carcinoma (RCCC) in children and its relationship to the DNA content of cancer cells and DNA ploidy.

METHODS

The pathologic morphology of 4 cases of RCCC in children were observed. Using image analysis instruments the quantity of tumor cell DNA was measured.

RESULTS

The cytoplasm of the tumor cells were clear in all four cases. Papillary structures were present in these tumors, of which the papillary structure in two cases was over 50%, three cases had small calcified bodies with prominent bleeding and necrosis. Around tumor the glomerular and tubular of kidney always is normal the average DNA index was 1.31. They presented diploidy, high diploidy or subtetraploidy.

CONCLUSIONS

The specific features of most RCCC in children are clear cytoplasm, most contain papillary structures, calcified bodies, often with bleeding and necrosis. Around tumor the glomerular and tubular of kidney is always normal. The DNA contents of cancer cells present diploidy, high diploidy or subtetraploidy.

[The research on the chemical components of Schizonepeta tenuifolia Briq]

Eicosane acid, beta-sitosterol, oleanolic acid, ursolic acid and daucosterol have been firstly isolated and identified from Schizonepeta tenuifolia Briq..

Secretory leukocyte protease inhibitor, an inhibitor of neutrophil activation, is elevated in serum in human sepsis and experimental endotoxemia

OBJECTIVES

To document changes in serum secretory leukocyte protease inhibitor (SLPI) in human sepsis and in experimental endotoxemia in vivo. To compare changes in serum SLPI in human sepsis with changes in interleukin (IL)-6, IL-10, and tumor necrosis factor (TNF)-alpha. To determine whether or not changes in SLPI correlate with the severity of multiple organ dysfunction syndrome as measured by the maximal multiple organ dysfunction score. Finally, because neutrophils have been implicated in tissue injury associated with organ dysfunction, to determine whether recombinant human SLPI blocks activation of isolated human neutrophils.

DESIGN

Case-control study and ex-vivo cellular assay.

SETTING

Surgical intensive care unit and clinical research center of university hospitals; laboratory of a medical school.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

There was a significant dose-dependent elevation (50.2+/-4.0 ng/mL, p = .01) in plasma SLPI 12 hrs after administration of lipopolysaccharide to seven healthy adults (36.4+/-2.3 ng/mL). Further, serum concentrations of SLPI (132+/-15 ng/mL) were elevated in septic surgical patients compared with healthy controls (43+/-2 ng/mL, p < .01) and nonseptic surgical controls (69+/-10 ng/mL, p = .01). Serum SLPI concentrations correlated (r2 = .71, p < .01) better with organ dysfunction as measured by maximal multiple organ dysfunction score than did serum IL-6 (r2 = .49, p < .01), IL-10 (r2 = .05, p = .22), or TNF-alpha (r2 = .02, p = .44). We found that recombinant human SLPI in vitro inhibits TNF-alpha-induced hydrogen peroxide production by human neutrophils (ID50 = 1-2 microg/mL).

CONCLUSIONS

Serum SLPI is elevated in human sepsis and experimental endotoxemia. Maximal concentrations of serum SLPI correlate significantly with maximal multiple organ dysfunction scores in patients with sepsis. Secretory leukocyte protease inhibitor may function to limit ongoing neutrophil-mediated tissue injury associated with organ dysfunction.

Suppression of macrophage responses to bacterial lipopolysaccharide by a non-secretory form of secretory leukocyte protease inhibitor

Expression of secretory leukocyte protease inhibitor (SLPI) suppresses the ability of macrophages to respond to bacterial lipopolysaccharide (LPS). Here, addition of recombinant or native SLPI to the extracellular medium was non-suppressive, while transfection with a non-secretory form of SLPI was fully suppressive, an effect overcome by treatment with interferon-gamma. A portion of the SLPI produced by untransfected macrophages was localized in the cytosol. Thus, SLPI can act intracellularly to block macrophage activation by LPS.

Secretory leukocyte protease inhibitor interferes with uptake of lipopolysaccharide by macrophages

Macrophages are among the most sensitive targets of bacterial endotoxin (LPS), responding to minute amounts of LPS by releasing a battery of inflammatory mediators. Transfection of macrophages with secretory leukocyte protease inhibitor (SLPI) renders these cells refractory to LPS stimulation. Here we show that uptake of LPS from soluble CD14 (sCD14)-LPS complexes by SLPI-overexpressing cells was only 50% of that seen in control cells. SLPI transfectants and mock transfectants did not differ in the surface expression of CD14 or CD18. We show, in addition, that recombinant human SLPI can bind to purified endotoxin in vitro. SLPI caused a decrease in the binding of LPS to sCD14 as assessed both by fluorescence quenching of labeled LPS and by nondenaturing polyacrylamide gel electrophoresis. These results suggest that the inhibitory effect of SLPI on macrophage responses to LPS may, in part, be due to its blockade of LPS transfer to soluble CD14 and its interference with uptake of LPS from LPS-sCD14 complexes by macrophages.

Prospective study of symptom control in 133 cases of palliative care inpatients in Shatin Hospital

We report a prospective study assessing the prevalence and severity of physical and nonphysical symptoms, and the benefits from treatment and intervention, in advanced cancer patients presenting to a local palliative care unit in Hong Kong. Patients were assessed by a modified version of the support team assessment schedule (STAS). The study highlighted some symptoms which needed better control, and also reinforced the team morale by demonstrating aspects where there was definite improvement. In general, the STAS was found to be practicable and acceptable by our patients and staff. The most important benefit gained from the study was the successful dissemination of the concept of audit and quality assurance throughout the unit, which is essential for continuous improvement in the future.

Heat shock protein 90 mediates macrophage activation by Taxol and bacterial lipopolysaccharide

Taxol, a plant-derived antitumor agent, stabilizes microtubules. Taxol also elicits cell signals in a manner indistinguishable from bacterial lipopolysaccharide (LPS). LPS-like actions of Taxol are controlled by the lps gene and are independent of binding to the known Taxol target, beta-tubulin. Using biotin-labeled Taxol, avidin-agarose affinity chromatography, and peptide mass fingerprinting, we identified two Taxol targets from mouse macrophages and brain as heat shock proteins (Hsps) of the 70- and 90-kDa families. Geldanamycin, a specific inhibitor of the Hsp 90 family, blocked the nuclear translocation of NF-kappaB and expression of tumor necrosis factor in macrophages treated with Taxol or with LPS. Geldanamycin did not block microtubule bundling by Taxol or macrophage activation by tumor necrosis factor. Thus, Taxol binds Hsps, and Hsp 90 helps mediate the activation of macrophages by Taxol and by LPS.

Paradoxical preservation of a lipopolysaccharide response in C3H/HeJ macrophages: induction of matrix metalloproteinase-9

C3H/HeJ mice carry a mutant allele (Lpsd) of a recently identified gene whose normal allele (Lpsn) confers responsiveness to bacterial LPS in C3H/HeN and most other mouse strains. Recently we reported differential display analysis of matched macrophage-derived cell lines from C3H/HeJ and C3H/HeN mice under LPS-free conditions. Of the approximately 12,000 transcripts evaluated, 4 were differentially expressed. One transcript represented secretory leukocyte protease inhibitor. In this study, we report another differentially expressed transcript, mouse matrix metalloprotease-9 (MMP-9). Like secretory leukocyte protease inhibitor, MMP-9 was expressed constitutively in the Lpsd macrophage cell line and not in the Lpsn cell line. Similarly, two additional macrophage cell lines that respond readily to LPS by producing nitric oxide and TNF expressed no MMP-9 under LPS-free conditions. However, in all four cell lines, LPS induced MMP-9 or augmented its expression. In primary macrophages, concentrations of LPS in the ng/ml range augmented the expression of MMP-9 mRNA. Paradoxically, macrophages from Lpsd mice expressed more MMP-9 transcripts than macrophages from Lpsn mice. In contrast, the induction of TNF in response to LPS was much more pronounced in Lpsn macrophages. The present findings with MMP-9 suggest that homozygosity at Lpsd does not so much prevent a response to LPS as dysregulate it, resulting in the suppression of some LPS signaling pathways and the preservation of others.

Identification of genes involved in innate responsiveness to bacterial products by differential display

To explore gene regulation by bacterial lipopolysaccharide (LPS), we compared mRNA profiles of macrophage cell lines from two strains of mice congenic for a locus markedly affecting their ability to respond to LPS. Differential display detected four differentially expressed transcripts. One transcript encoded the mouse homolog of human secretory leukocyte protease inhibitor (SLPI), which was expressed by LPS-hyporesponsive macrophage cells (Lps(d)) but not by LPS-normoresponsive cells (Lps(n)). Among five macrophage cell lines, secretion of SLPI was inversely correlated with ability to produce nitric oxide (NO) and tumor necrosis factor alpha in response to LPS. Stable transfection of LPS-responsive macrophages with SLPI suppressed LPS-induced responses. Interferon-gamma (IFN-gamma), which corrects the defective LPS response in Lps(d) macrophages, suppressed the LPS-induced expression of SLPI and restored LPS response to SLPI-overexpressing macrophages. Besides its role as a LPS response inhibitor, mouse SLPI is also a lipoteichoic acid response inhibitor. The expression of SLPI was strongly enhanced by interleukin-10 and -6. SLPI may be an important antiinflammatory molecule in host defense against gram-negative and gram-positive bacteria.

[The technology of processing carbonized Cirsium japonicum and quality standards of its prepared pieces]

The technology of processing carbonized Cirsium japonicum was selected by using orthogonal experiment design. The result shows that the best way is to bake of 10 min at 220 degrees C. The contents of macro and trace elements in the prepared pieces significantly increased.

Lipopolysaccharide-related stimuli induce expression of the secretory leukocyte protease inhibitor, a macrophage-derived lipopolysaccharide inhibitor

Mouse secretory leukocyte protease inhibitor (SLPI) was recently characterized as a lipopolysaccharide (LPS)-induced product of macrophages that antagonizes their LPS-induced activation of NF-kappaB and production of NO and tumor necrosis factor (TNF) (F. Y. Jin, C. Nathan, D. Radzioch, and A. Ding, Cell 88:417-426, 1997). To better understand the role of SLPI in innate immune and inflammatory responses, we examined the kinetics of SLPI expression in response to LPS, LPS-induced cytokines, and LPS-mimetic compounds. SLPI mRNA was detectable in macrophages by Northern blot analysis within 30 min of exposure to LPS but levels peaked only at 24 to 36 h and remained elevated at 72 h. Despite the slowly mounting and prolonged response, early expression of SLPI mRNA was cycloheximide resistant. Two LPS-induced proteins-interleukin-10 (IL-10) and IL-6-also induced SLPI, while TNF and IL-1beta did not. The slow attainment of maximal induction of SLPI by LPS in vitro was mimicked by infection with Pseudomonas aeruginosa in vivo, where SLPI expression in the lung peaked at 3 days. Two LPS-mimetic molecules-taxol from yew bark and lipoteichoic acid (LTA) from gram-positive bacterial cell walls-also induced SLPI. Transfection of macrophages with SLPI inhibited their LTA-induced NO production. An anti-inflammatory role for macrophage-derived SLPI seems likely based on SLPI's slowly mounting production in response to constituents of gram-negative and gram-positive bacteria, its induction both as a direct response to LPS and as a response to anti-inflammatory cytokines induced by LPS, and its ability to suppress the production of proinflammatory products by macrophages stimulated with constituents of both gram-positive and gram-negative bacteria.

Radix Salviae miltiorrhizae protects rat hippocampal neuron in culture from anoxic damage

Radix Salviae Miltiorrhizae (RSM), a well-known traditional Chinese medicinal herb, has been used to improve blood circulation and resolve blood stasis. We have previously found that RSM has neuroprotective effect on ischemia and/or ischemia-reperfusion rats. The purpose of this study was to obtain further information on the mechanism of the RSM-induced neuroprotection and to examine the neuroprotective effect on neurons exposed to anoxia. The effect of RSM on anoxic damage in cultured hippocampal neurons of neonatal rat was investigated by using morphological changes and heat shock protein 70 kD (HSP70) expression as indicators. RSM given 0.5 h before 2 h-anoxia followed by 48 hours reoxygenation could significantly increase survival rate of hippocampal neurons and number of HSP70 positive cells. The results suggest that RSM has a direct neuroprotective effects on anoxic damage in hippocampal neurons.

[Anoxia-induced c-fos expression of cultured rat hippocampal neurons and effect of recombinant human interleukin-1 beta]

Effects of recombinant human interleukin-1 beta (rhIL-1 beta) on the c-fos expression of cultured rat hippocampal neurons in vitro induced by anoxia were studied by using an immunohistochemical method. The results showed that the percentage and the mean optical density of the Fos-positive neuronal nuclei in cultured hippocampal neurons increased markedly as anoxia prolonged, while those in hippocampal neurons pretreated with rhIL-1 beta were significantly lower than those of control. The results indicate that anoxia can induce c-fos expression of cultured rat hippocampal neurons in vitro and this can be inhibited by rhIL-1 beta, suggesting that rhIL-1 beta may protect neurons from damage in a certain degree during anoxia.

[Role of Na+/Ca2+ exchange blocker in rat hippocampal injury during anoxia]

Effects of Na+/Ca2+ exchange blocker, Benzamil, on rat hippocampal slices and on cultured hippocampal neuronal [Ca2+]i (intracellular free Ca2+ concentration) during anoxia were investigated by means of microelectrode recording technique and laser scanning confocal microscope respectively. The results showed that the PV sustained time of hippocampal slices pretreated with Benzamil (50 mumol) after anoxia was markedly longer than that of control, suggesting that inhibition of Na+/Ca2+ exchange can delay the irreversible injury to hippocampal cells. Moreover, by using a confocal microscope we found that acute anoxia induced a rapid increase of [Ca2+]i in hippocampal neurons and this could be significantly attenuated by 20 mumol Benzamil. All these results indicate that Na+/Ca2+ exchanger is involved in the anoxic injury to rat hippocampus and it may be one of the major ways leading to the anoxia-induced [Ca2+]i increase of hippocampal neurons.

Secretory leukocyte protease inhibitor: a macrophage product induced by and antagonistic to bacterial lipopolysaccharide

To explore regulation of potentially lethal responses to bacterial lipopolysaccharide (LPS), we used differential display under LPS-free conditions to compare macrophage cell lines from two strains of mice congenic for a locus affecting LPS sensitivity. LPS-hyporesponsive cells, primary macrophages, and polymorphonuclear leukocytes transcribed secretory leukocyte protease inhibitor (SLPI), a known epithelial cell-derived inhibitor of leukocyte serine proteases. Transfection of macrophages with SLPI suppressed LPS-induced activation of NF-kappa B and production of nitric oxide and TNF alpha. The ability of interferon-gamma (IFN gamma) to restore LPS responsiveness is a hallmark of the LPS-hyporesponsive phenotype. IFN gamma suppressed expression of SLPI and restored LPS responsiveness to SLPI-producing cells. Thus, SLPI is an LPS-induced IFN gamma-suppressible phagocyte product that serves to inhibit LPS responses.

[Studies on the effective constituents of arresting bleeding of Schizonepeta tenuifolia]

Schizonepeta tenuifolia (Benth.) Briq fried with carbon is used in various bleeding diseases in order to further investigate the effective constituents of arresting bleeding in Schizonepeta tenuifolia(benth.) Briq and to finish the quality standard of its capsule. We isolate the chemical constituents from Schizonepeta tenuifola(Benth.) Briq fried with carbon and study its action of arresting bledding and assay the effective constituents of arresting bleeding in capsule.

[Influence of processing on quercetin content in flos Sophorae immaturus]

The HPLC method was applied to determine the quercetin content in Flos Sophorae Immaturus. The technology for processing Flos Sophorae Immaturus was selected based on orthogonal experiment design. The result has shown that the better technology is to bake Flos Sophorae Immaturus for 11 min at the temperature of 180 degrees C.

Association of mitogen-activated protein kinases with microtubules in mouse macrophages

Taxol, a microtubule-binding diterpene, mimics many effects of lipopolysaccharide (LPS) on mouse macrophages. The LPS-mimetic effects of taxol appear to be under the same genetic control as responses to LPS itself. Thus we have postulated a role for microtubule-associated proteins (MAP) in the response of macrophages to LPS. Stimulation of macrophages by LPS quickly induces the activation of mitogen-activated protein kinases (MAPK). MAPK are generally considered cytosolic enzymes. Herein we report that much of the LPS-activatable pool of MAPK in primary mouse peritoneal macrophages is microtubule associated. By immunofluorescence, MAPK were localized to colchicine- and nocodazole-disruptible filaments. From both mouse brain and RAW 264.7 macrophages, MAPK could be coisolated with polymerized tubulin. Fractionation of primary macrophages into cytosol-, microfilament-, microtubule-, and intermediated filament-rich extracts revealed that approximately 10% of MAPK but none of MAPK kinase (MEK1A and MEK2) was microtubule bound. Exposure of macrophages to LPS did not change the proportion of MAPK bound to microtubules, but preferentially activated the microtubule-associated pool. These findings confirm the prediction that LPS activates a kinase bound to microtubules. Together with LPS-mimetic actions of taxol and the shared genetic control of responses to LPS and taxol, these results support the hypothesis that a major LPS-signaling pathway in mouse macrophages may involve activation of one or more microtubule-associated kinases.

[Determination of paeonol in carbonized bark of Paeonia suffruticosa Andr. by HPLC]

The contents of paeonol in prepared pieces of carbonized bark of Paeonia suf fruticosa were determined by HPLC. The result shows that the contents of paeonol decrease with the rise of temperature and the extension of time in processing.

[Technology of processing carbonized root of Sanguisorba of ficinalis L. and the quality standards for its prepared pieces]

The technology of processing carbonized root of Sanguisorba of ficinalis was selected using orthogonal experiment design. The result shows that the best way is to stir-fry the drug in a pan for 7.5 min at 250 degrees C. The contents of trace elements in the prepared piece are significantly increased, and the prepared piece have marked hemostatic and bacteriostastic effects.

alpha-Toxin perfusion: a new method for selective impairment of endothelial function in isolated vessels or intact vascular beds

We describe a method for selectively permeabilizing endothelial cells, using the membrane pore forming exoprotein Staphylococcus aureus alpha-toxin. Experiments were performed in rabbit central ear artery or its main side branch under isometric conditions, on the isolated perfused kidney, or in cannulated pressurized renal arteries. In presence of alpha-toxin, endothelial-dependent vasodilator responses elicited by acetylcholine or A23187 were abolished, whereas the sensitivity of smooth muscle cells to constrictors (norepinephrine, phenylephrine, or KCl) or dilators (sodium nitroprusside) was not affected. The results indicate that restricting the alpha-toxin to the luminal surface induces selective impairment of vascular endothelial function. This method of eliminating endothelium-dependent vasodilator responses may prove to be useful in the study of endothelial-smooth muscle interactions of isolated small arteries and intact vascular beds.

Synthesis and mass-spectrometric characterization of human serum albumins modified by covalent binding of two non-steroidal anti-inflammatory drugs: tolmetin and zomepirac

Human serum albumins modified by covalently bound tolmetin or zomepirac were synthesized as models for similar products formed in vivo from acyl glucuronides. Activated esters of both drugs were prepared with 1-ethyl-3-(3-dimethylaminopropyl)-carbodi-imide, and then allowed to react with human serum albumin. Tryptic digests of both protein products were analysed by HPLC to identify peptides containing covalently bound drugs, and binding sites on albumin were identified by high-performance tandem MS. Three binding sites were common to both products, i.e. lysine-195, -199 and -351. Three further modified residues were identified for the tolmetin-albumin product, i.e. aspartic acid 1, and lysine-524 and -536.

Holeboard maze-learning deficits and brain monoaminergic neurotransmitter concentrations in rats after intracerebroventricular injection of 3-bromopyruvate

3-Bromopyruvate is a suicide inhibitor of pyruvate dehydrogenase complex in brain homogenates, and after intracerebral injection reduces acetylcholine tissue content and muscarinic cholinergic receptors in brain cortex and hippocampus for extended periods of time. A stereotaxic injection of 0.2 mumol 3-bromopyruvate was given twice into the cerebral ventricles of male Wistar rats. Ten weeks later, the animals were tested for learning deficits in a food-motivated complex holeboard test. 3-Bromopyruvate-treated rats showed an increased number of visits to nonfood-baited holes over a 5-day testing period (four trials per day) compared to sham-operated control rats, an increased number of visits to food-baited holes over the first 2 days of the testing period and an increased time for completing the task. There were no changes in brain monoaminergic neurotransmitter concentrations compared to controls. The results indicate that long-term learning deficits in a spatial discrimination paradigm are caused by 3-bromopyruvate, which might be related to a cholinergic deficit induced by a primary inhibition of brain glucose metabolism at the step of pyruvate dehydrogenase complex. This animal model may be useful for behavioral studies in relation to neurodegenerative diseases like dementia of Alzheimer type.

Reactivity of tolmetin glucuronide with human serum albumin. Identification of binding sites and mechanisms of reaction by tandem mass spectrometry

The structures of adducts formed from in vitro incubation of a drug (tolmetin) glucuronide (TG) and human serum albumin (HSA), and the preferred binding sites on this protein were determined by mass spectrometry. In addition, the concentration dependence of covalent modification of HSA by TG was studied at three different concentration ratios of TG to HSA. Protein adducts were enzymatically digested and peptide fragments were separated by HPLC. Tolmetin-containing peptides (indicated by absorbance at 313 nm) were analyzed by liquid secondary-ion mass spectrometry, continuous flow-fast atom bombardment mass spectrometry, and collision-induced dissociation using a four-sector tandem mass spectrometer, matrix-assisted laser desorption ionization-time-of-flight-mass spectrometry, and in selected cases by Edman sequencing. The identified peptides contained tolmetin linked covalently via a glucuronic acid to a protein lysine group (lysine 199 and to a lesser extent lysines 195 and 525) or tolmetin directly linked to lysines (lysines 199 and 541), serines (serines 220, 232, and 480), or arginines (arginine 222). In addition, there was indirect evidence for binding of TG to lysine 541, and binding of tolmetin to arginine 521. Our results establish that the binding of these reactive metabolites to nucleophilic sites of proteins occur via two different mechanisms: one involving imine (Schiff base) formation and the other involving nucleophilic displacement of glucuronic acid. Our data suggest, however, that the former, in which the glucuronic acid moiety of the acyl glucuronide is retained within the adducts, is favored at lower (closer to physiological) metabolite concentrations.

Activation of NF-kappa B in murine macrophages by taxol

Taxol, a plant-derived antimitotic, was recently found to mimic several of the effects of endotoxic bacterial lipopolysaccharide on murine macrophages. However, the mechanisms underlying the cell cycle-independent actions of taxol remain unclear. Here, we report that taxol rapidly activated nuclear factor kappa B (NF-kappa B) in mouse peritoneal macrophages. The intranuclear transcription factor complexes contained two NF-kappa B heterodimers, p50/RelA and p50/c-rel. Taxol-induced nuclear translocation of NF-kappa B was inhibited by pyrrolidine dithiocarbamate, an antioxidant, but not by cycloheximide, a protein synthesis inhibitor. The ability of taxol to activate NF-kappa B may help account for its induction of immunoregulatory and cytotoxic cytokines, which in turn may contribute to its antitumor effects.

Macrophages derived from C3H/HeJ (Lpsd) mice respond to bacterial lipopolysaccharide by activating NF-kappa B

The effects of bacterial lipopolysaccharide (LPS) on macrophage gene expression are mediated in part by its ability to induce activation of transcription factor NF-kappa B. We compared the ability of LPS-treated macrophages from Lpsn (LPS-responsive) C3H/HeN and Lpsd (LPS-hyporesponsive) C3H/HeJ mice to mobilize NF-kappa B by electrophoretic mobility shift assays with oligonucleotide probes containing a unique NF-kappa B sequence from the promoter of inducible nitric oxide synthase (iNOS). In response to ng/ml concentrations of LPS, this probe bound proteins that appeared rapidly in the nuclei of thioglycollate-elicited macrophages and bone marrow-derived macrophage cell lines from both Lpsn and Lpsd mice. Only in macrophages from Lpsn mice, however, was LPS able to induce iNOS or tumor necrosis factor alpha. NF-kappa B-containing DNA-protein complexes from Lpsd macrophages were formed in lesser amounts than from Lpsn macrophages but shared the same composition, insofar as they displayed the same electrophoretic mobilities and content of heterodimers of p50/RelA (p65) and p50/c-rel. Two conclusions emerge from these findings: (1) NF-kappa B activity alone is not sufficient for induction of certain LPS-responsive genes and (2) An LPS-response pathway involving activation of NF-kappa B is preserved in Lpsd mice. The inability of cells from Lpsd mice to induce gene expression in response to LPS thus cannot be attributed to inability to activate NF-kappa B.

Effect of aging on murine macrophages. Diminished response to IFN-gamma for enhanced oxidative metabolism

The ability of macrophages to secrete reactive oxygen intermediates, as well as reactive nitrogen intermediates, correlates closely with their capacity to perform two critical effector functions: intracellular killing of microorganisms and lysis of tumor cells. In this study, age-associated changes in the ability of caseinate-elicited peritoneal macrophages to release hydrogen peroxide were determined. Macrophages from aged BALB/c mice produced 50% less hydrogen peroxide than those from young mice in response to PMA or opsonized zymosan. In contrast, the production of macrophage-activating cytokines including IFN-gamma was not diminished in splenocyte supernatants from the aged group. Furthermore, no difference was detected in surface expression of IFN-gamma receptor in old and young mice. Macrophage responses to IFN-gamma, however, declined with aging. In vitro, IFN-gamma-induced release of hydrogen peroxide and nitric oxide was 50% lower in old mice than in young mice. IFN-gamma-induced tyrosine phosphorylation of MAPK, an early activation event, was undetectable in macrophages from the aged mice. These data demonstrate that diminished responses of macrophages to activating signals are one aspect of the impaired immune response in aged mice.

Effect of aging on murine macrophages. Diminished response to IFN-gamma for enhanced oxidative metabolism

The ability of macrophages to secrete reactive oxygen intermediates, as well as reactive nitrogen intermediates, correlates closely with their capacity to perform two critical effector functions: intracellular killing of microorganisms and lysis of tumor cells. In this study, age-associated changes in the ability of caseinate-elicited peritoneal macrophages to release hydrogen peroxide were determined. Macrophages from aged BALB/c mice produced 50% less hydrogen peroxide than those from young mice in response to PMA or opsonized zymosan. In contrast, the production of macrophage-activating cytokines including IFN-gamma was not diminished in splenocyte supernatants from the aged group. Furthermore, no difference was detected in surface expression of IFN-gamma receptor in old and young mice. Macrophage responses to IFN-gamma, however, declined with aging. In vitro, IFN-gamma-induced release of hydrogen peroxide and nitric oxide was 50% lower in old mice than in young mice. IFN-gamma-induced tyrosine phosphorylation of MAPK, an early activation event, was undetectable in macrophages from the aged mice. These data demonstrate that diminished responses of macrophages to activating signals are one aspect of the impaired immune response in aged mice.

Taxol shares the ability of bacterial lipopolysaccharide to induce tyrosine phosphorylation of microtubule-associated protein kinase

Microtubule-associated proteins may mediate the activation of macrophages by bacterial LPS. Three lines of evidence support this hypothesis: a) Taxol, a microtubule-binding diterpene, mimics the ability of LPS to induce cytokines and down-regulate receptors for TNF-alpha. In recombinant inbred mouse strains differing at the Lps gene, responsiveness to these effects of Taxol co-segregates with responsiveness to LPS. b) In vitro, LPS binds specifically to MT and preferentially to beta-tubulin. c) LPS activates microtubule-associated protein-2 kinase (MAPK). The present studies bring together and extend these lines of evidence. a) Taxol, like LPS, rapidly induces tyrosine phosphorylation of MAPK in mouse macrophages, and triggers MAPK to phosphorylate an exogenous substrate. b) Tyrosine phosphorylation of MAPK is an extremely rapid cellular response both to taxol and LPS. c) Macrophages from C3H/HeJ mice, which carry a defective Lps gene, fail to activate MAPK in response to taxol or LPS, although they activate MAPK in response to insulin or IFN-gamma. These results suggest that tyrosine phosphorylation of MAPK is among the earliest known response of macrophages to LPS. Taxol mimics LPS with respect to immediate MAPK activation, later transcriptional events, and the genetic control of both sets of responses. LPS and taxol thus appear to share an early step in a functionally important signal transduction pathway that may involve MT.

Taxol shares the ability of bacterial lipopolysaccharide to induce tyrosine phosphorylation of microtubule-associated protein kinase

Microtubule-associated proteins may mediate the activation of macrophages by bacterial LPS. Three lines of evidence support this hypothesis: a) Taxol, a microtubule-binding diterpene, mimics the ability of LPS to induce cytokines and down-regulate receptors for TNF-alpha. In recombinant inbred mouse strains differing at the Lps gene, responsiveness to these effects of Taxol co-segregates with responsiveness to LPS. b) In vitro, LPS binds specifically to MT and preferentially to beta-tubulin. c) LPS activates microtubule-associated protein-2 kinase (MAPK). The present studies bring together and extend these lines of evidence. a) Taxol, like LPS, rapidly induces tyrosine phosphorylation of MAPK in mouse macrophages, and triggers MAPK to phosphorylate an exogenous substrate. b) Tyrosine phosphorylation of MAPK is an extremely rapid cellular response both to taxol and LPS. c) Macrophages from C3H/HeJ mice, which carry a defective Lps gene, fail to activate MAPK in response to taxol or LPS, although they activate MAPK in response to insulin or IFN-gamma. These results suggest that tyrosine phosphorylation of MAPK is among the earliest known response of macrophages to LPS. Taxol mimics LPS with respect to immediate MAPK activation, later transcriptional events, and the genetic control of both sets of responses. LPS and taxol thus appear to share an early step in a functionally important signal transduction pathway that may involve MT.