Rapid up-regulation of endothelial nitric-oxide synthase in a mouse model of Escherichia coli lipopolysaccharide-induced bladder inflammation

Increases in the signaling molecule nitric oxide (NO) during inflammation may be linked not only to inducible nitric-oxide synthase (iNOS) but also to endothelial (e)NOS. Escherichia coli lipopolysaccharide (LPS) induces an inflammatory response in the bladder and rapidly increases phosphorylation of Akt/protein kinase B (Akt), a key enzyme regulating proliferation, apoptosis, and inflammation. Activated Akt phosphorylates human eNOS at serine 1177 and subsequently increases NOS activity. Because Akt and eNOS are both localized in the bladder urothelium, phosphorylation of eNOS by Akt provides an attractive mechanism for rapid increases in urinary NO production. Female mice were intraperitoneally injected with LPS (25 mg/kg) or pyrogen-free water (control). Four hours before LPS injection, some mice were injected with wortmannin, which inhibits Akt phosphorylation. Levels of urinary cyclic GMP, a downstream product of NO, increase 75% within 1 h after intraperitoneal injection of LPS, and this increase is blocked by wortmannin. Bladder eNOS and phosphorylated eNOS protein increase 94 and 151%, respectively, 1 h after LPS treatment, whereas iNOS was not detected. Wortmannin decreases eNOS phosphorylation by 60%. Furthermore, bladder Ca(2+)-dependent NOS activity (eNOS, neuronal NOS) is increased 79 +/- 20% 1 h after LPS treatment, whereas there is no increase in Ca(2+)-independent (iNOS) activity (n = 4). Increases in urinary cyclic GMP, NOS activity, and eNOS protein and phosphorylation 1 h after induction of inflammation with LPS, indicate that eNOS plays a role in the early response to bladder inflammation.     

Real-time assessment of inflammation and treatment response in a mouse model of allergic airway inflammation

Eosinophils are multifunctional leukocytes that degrade and remodel tissue extracellular matrix through production of proteolytic enzymes, release of proinflammatory factors to initiate and propagate inflammatory responses, and direct activation of mucus secretion and smooth muscle cell constriction. Thus, eosinophils are central effector cells during allergic airway inflammation and an important clinical therapeutic target. Here we describe the use of an injectable MMP-targeted optical sensor that specifically and quantitatively resolves eosinophil activity in the lungs of mice with experimental allergic airway inflammation. Through the use of real-time molecular imaging methods, we report the visualization of eosinophil responses in vivo and at different scales. Eosinophil responses were seen at single-cell resolution in conducting airways using near-infrared fluorescence fiberoptic bronchoscopy, in lung parenchyma using intravital microscopy, and in the whole body using fluorescence-mediated molecular tomography. Using these real-time imaging methods, we confirmed the immunosuppressive effects of the glucocorticoid drug dexamethasone in the mouse model of allergic airway inflammation and identified a viridin-derived prodrug that potently inhibited the accumulation and enzyme activity of eosinophils in the lungs. The combination of sensitive enzyme-targeted sensors with noninvasive molecular imaging approaches permitted evaluation of airway inflammation severity and was used as a model to rapidly screen for new drug effects. Both fluorescence-mediated tomography and fiberoptic bronchoscopy techniques have the potential to be translated into the clinic.     

Cooperation between Th1 and Th2 cells in a murine model of eosinophilic airway inflammation

We have studied the actions of helper T lymphocyte-1 and -2 (Th1 and Th2) cells in an acute model of eosinophilic airway inflammation by infusing chicken ovalbumin-specific (OVA-specific) Th1 cells, Th2 cells, or both into unsensitized mice and challenging the mice with an OVA aerosol. OVA challenge after infusion of Th1 cells alone resulted in airway inflammation with lymphocytes and monocytes. Challenge after the infusion of Th2 cells alone resulted in minimal inflammation. In contrast, when Th1 and Th2 cells were transferred together, they cooperated to promote a robust eosinophil-predominant inflammatory response. Th1 cells alone were readily recruited to the airways after challenge, but in the absence of Th1 cells, Th2 cells did not accumulate in the airways. When transferred together, both Th1 and Th2 cells, as well as endogenous eosinophils, were effectively recruited. This recruitment was correlated with increased VCAM-1 expression in the medium- and large-sized vessels of the lung and could be inhibited by treating the mice with neutralizing antibodies to TNF-alpha or VCAM-1. These data indicate that Th2 cells require signals in addition to antigen for their effective recruitment to the airways. Th1 cells can provide these signals.     

Proteases involved in airway inflammation of COPD

Chronic obstructive pulmonary disease(COPD) is one of major cause of morbidity and mortality worldwide. Cigarette smoking is the main risk factor for the development of COPD and causes airway inflammation and parenchymal destruction. In the pathogenesis of COPD, protease-antiprotease imbalance is considered to be one of the important processes through the study of alpha 1-antitrypsin deficiency. At present, not only neutrophil elastase but also cathepsin and matrix metalloproteinases produced by inflammatory cells are demonstrated to be important in the pathogenesis of COPD, In this review, the roles of various kinds of proteases in the airway inflammation are summarized.     

慢性咳嗽患者的呼吸道嗜酸性粒细胞性炎性反应特征

目的探讨慢性咳嗽患者的呼吸道嗜酸性粒细胞炎性反应特征。方法使用诱导痰嗜酸性粒细胞计数检查123例慢性咳嗽患者的呼吸道嗜酸性粒细胞性炎性反应情况,其中咳嗽变异型哮喘(CVA)44例、嗜酸性粒细胞性支气管炎(EB)27例、上气道咳嗽综合征(UACS)26例、变应性咳嗽(AC)17例和胃食管反流相关性咳嗽(GERC)9例。收集56例典型哮喘(CA)患者和25例健康者的诱导痰嗜酸性粒细胞计数结果进行统计学比较。结果慢性咳嗽患者呼吸道嗜酸性粒细胞炎性反应的阳性率为0.487 8(60/123),其中,CVA组和EB组分别为0.750 0(33/44)和1.000 0(27/27),其他病因组均为0.000 0。CVA组与EB组之间的差异具有统计学意义(P=0.005),CVA组与CA组[0.821 4(46/56)]之间的差异无统计学意义(P=0.507),EB组与CA组之间差异具有统计学意义(P=0.019),CVA组、EB组分别与UACS组、AC组、GERC组、健康对照组比较,差异具有统计学意义(P值均为0.000)。呼吸道嗜酸性粒细胞炎性反应患者的诱导痰嗜酸性粒细胞比值,EB组低于CVA组(Z=-2.551,P=0.011)和CA组(Z=-3.190,P=0.001),CVA组与CA组之间差异无统计学意义(Z=-0.801,P=0.423)。结论嗜酸性粒细胞性炎性反应是慢性咳嗽患者的一种主要的呼吸道炎性反应类型,主要见于CVA和EB患者。CVA和EB的呼吸道嗜酸性粒细胞性炎性反应程度不同。     

嗜酸粒细胞性支气管炎与咳嗽变异性哮喘患者的气道炎症特征的研究

目的研究嗜酸粒细胞性支气管炎以及咳嗽变异性哮喘病人气道炎性细胞因子与炎性介质的主要特性。方法嗜酸粒细胞性支气管炎(EB)组16例患者、咳嗽变异性哮喘(CVA)组16例患者、哮喘组15例患者以及对照组15例正常体检者,检测这4组人员诱导痰中的嗜酸粒细胞即嗜酸粒细胞(EOS)比例;流式检测白细胞介素-5(IL-5)和γ-干扰素(IFN-γ)刺激的EOS表面CD69蛋白的表达;酶联免疫吸附(ELISA)法检测各组患者诱导痰上清液中前列腺素E2(PGE2)、白三烯C4(LTC4)的蛋白表达量。结果 EB组、CVA组、哮喘组患者诱导痰中EOS表面CD69蛋白的表达量差异无统计学意义,与对照组相比差异有统计学意义(均P<0.05)。EB组、CVA组、哮喘组患者诱导痰中PGE2浓度比较差异有统计学意义(均P<0.05);与对照组相比,CVA组患者、EB患者以及哮喘组患者的诱导痰中LTC4浓度显著增高(均P<0.05),EB组患者的LTC4的蛋白表达量和CVA组患者以及哮喘组患者的差异进行比较,同样具有统计学意义(均P<0.05)。CVA组患者以及哮喘组患者诱导痰中LTC4/PGE2的比值与EB组患者相比显著增高(均P<0.05)。结论 EB组患者的诱导痰中PGE2的表达水平增高,CVA组患者的LTC4/PGE2比值与EB组患者相比也是明显升高,推测这两个因素是EB缺乏气道反应性的潜在炎症基础。     

Role of neuronal nitric-oxide synthase in estrogen-induced relaxation in rat resistance arteries

Estrogen has antihypertensive and vasorelaxing properties, partly via activation of endothelial nitric-oxide synthase (eNOS). Recently, neuronal nitric-oxide synthase (nNOS) has been detected in vascular cells, although the significance of this is unclear. Estrogen was found to stimulate nNOS in certain cultured cells. We hypothesized that estrogen regulates vascular tone partly via endothelium-derived nNOS. Human umbilical vein endothelial cells were used to test whether acute (5 min) stimulation with 17β-estradiol (E2) at 1 or 10 nM affected nNOS activity. Small mesenteric arteries from Sprague-Dawley rats were examined for relaxation to E2 (0.001-10 μM) in the absence or presence of selective nNOS inhibitor [N-propyl-L-arginine (L-NPA); 2 μM] or pan-NOS inhibitor [Nω-nitro-L-arginine methyl ester (L-NAME); 100 μM] using a wire myograph. Immunostaining was used to visualize nNOS in rat mesenteric artery cross-sections. Western blotting measured total and phospho-nNOS in endothelial cell lysates and thoracic aorta homogenates. E2 rapidly increased (p < 0.001) activating phosphorylation of nNOS and nitric oxide (NO) production (as measured by 4-amino-5-methylamino-2,7-difluorofluorescein fluorescence) in endothelial cells. Likewise, E2 caused dose-dependent relaxation of arteries from female rats, which was blunted by both l-NPA and l-NAME (p < 0.001). In contrast, E2 response was modest in male animals and unaffected by NOS inhibition. It is noteworthy that there was a greater baseline presence of phospho-nNOS in male relative to female aortas. Although eNOS is believed to be the main source of NO in the vascular endothelium, we confirmed nNOS expression in endothelial cells. Endothelial nNOS mediated E2 relaxation in isolated arteries from female animals. Altogether, these data suggest vascular nNOS as a novel mechanism in E2 signaling.     

Neuronal nitric-oxide synthase inhibition facilitates adrenergic neurotransmission in rat mesenteric resistance arteries

The effects of nonselective nitric-oxide synthase (NOS) inhibitors [N-omega-nitro-L-arginine methyl ester (L-NAME) and N-omega-nitro-L-arginine (L-NNA)] and specific neuronal NOS (nNOS) inhibitor [vinyl-L-N-5-(1-imino-3-butenyl)-L-ornithine (L-VNIO)] on adrenergic nerve-mediated vasoconstriction were studied in rat perfused mesenteric vascular beds without endothelium. Perfusion of L-NAME, L-NNA, or l-VNIO markedly augmented vasoconstrictor responses to periarterial nerve stimulation (PNS; 2-8 Hz) without affecting vasoconstriction induced by exogenously injected norepinephrine (NE). Addition of L-arginine, a precursor for the synthesis of nitric oxide (NO), reversed the augmentation of the PNS response by l-NAME. The PNS (8 Hz)-evoked NE release in the perfusate was increased by L-NAME perfusion. In preparations treated with capsaicin [a depleter of calcitonin gene-related peptide (CGRP)-containing nerves], L-NAME did not augment vasoconstrictor responses to PNS or NE injection. Combined perfusion of CGRP(8-37) (a CGRP receptor antagonist) and L-NAME induced additive augmentation of the vasoconstrictor response to PNS but did not affect the response to NE injection. In preparations with active tone produced by methoxamine and in the presence of guanethidine, L-NAME perfusion did not affect the vasodilator response induced by PNS. Immunostaining of the mesenteric artery showed the presence of nNOS-like immunopositive nerve fibers, which were absent in arteries pretreated with capsaicin. These findings suggest that NO, which is released from perivascular capsaicin-sensitive nerves, presynaptically inhibits neurogenic NE release to modulate adrenergic neurotransmission.     

Electroacupuncture attenuates inflammation in a rat model

BACKGROUND: Acupuncture has traditionally been used in China and is being increasingly applied in Western countries to treat a variety of conditions, including inflammatory disease. However, clinical trials investigating the effectiveness of the anti-inflammatory effects of acupuncture have yielded inconsistent results, and the underlying mechanisms of acupuncture-produced anti-inflammation are unclear. OBJECTIVE: To evaluate the effectiveness of electroacupuncture (EA) on inflammation in a rat model. MATERIALS AND METHODS: Four experiments were conducted on male Sprague-Dawley rats (n = 8-9 per group). Inflammation was induced by injecting complete Freund's adjuvant (CFA) subcutaneously into the plantar surface of one hind paw of the rat. Experiment 1: To determine the effect of EA (10 and 100 Hz) versus sham treatment on inflammation. Experiment 2: To investigate the involvement of the adrenal glands on the effect of EA treatment using adrenalectomized (ADX) rats. Experiment 3: To determine the effects of EA on plasma levels of corticosterone. Experiment 4: To determine the effects of EA treatment versus immobilization on such stress indicators as heart rate and blood pressure. RESULTS: At 10 Hz EA significantly reduced CFA-induced hind paw edema. The effect was partially blocked in the ADX rats. EA significantly increased plasma levels of corticosterone but produced no noticeable signs of stress. CONCLUSION: At 10 Hz but not 100 Hz, EA suppresses inflammation by activating the hypothalamus-pituitary-adrenal axis (HPA) and the nervous system.     

Inositol phosphate metabolism and nitric-oxide synthase activity in endothelial cells are involved in the vasorelaxant activity of nebivolol

Nebivolol is a recently developed beta-blocker provided with vasodilator properties. Because the mechanism of the putative endothelium-dependent effect of this beta-adrenoceptor blocker has not been completely elucidated, the aim of this study was to investigate the effects of nebivolol on an isolated resistance vascular bed and on cell messengers and constitutive nitric-oxide synthase activity (cNOS) in endothelial cells. Experiments were carried out using the rat mesenteric vascular bed and cultured bovine coronary postcapillary venular endothelial cells from bovine heart (CVEC). In mesenteric vascular bed preconstricted by 30 microM noradrenaline and 0.3 microM U46619, dl-nebivolol induced a concentration-dependent relaxing effect at concentrations between 3 and 30 microM; this effect was changed to a concentration-dependent vasoconstrictor response either in endothelium-denuded preparations or in intact preparations pretreated with 100 microM N(omega)-nitro-L-arginine methyl ester plus 3 microM indomethacin. The vasorelaxant effect of dl-nebivolol in preconstricted preparations was completely blocked by pretreatment either with the phospholipase C inhibitor U73122 (1 microM) or with the endoplasmic reticulum Ca(2+)-ATPase inhibitor thapsigargin (1 microM) for 30 min. The cellular level of the inositol trisphosphate metabolite inositol monophosphate in coronary postcapillary venular endothelial cells was not affected by dl-nebivolol in the concentration range 100 nM to 1 microM, but it was concentration dependently increased after exposure for 15 min to 10 and 30 microM dl-nebivolol. The activity of cNOS was almost doubled after a 5-min exposure to 10 microM dl-nebivolol and was significantly impaired by thapsigargin and N(omega)-nitro-L-arginine methyl ester treatment, although it was unaffected by N(omega)-nitro-D-arginine methyl ester. These findings demonstrate that nebivolol, in micromolar concentrations, induces vasorelaxation through activation of inositol phosphate metabolism and stimulation of cNOS activity in endothelial cells.     

L-arginine chlorination results in the formation of a nonselective nitric-oxide synthase inhibitor

Reduced nitric oxide (NO) bioavailability and impaired vascular function are the key pathological characteristics of inflammatory diseases such as atherosclerosis. We have recently found that leukocyte-derived hypochlorous acid is able to react with the nitric-oxide synthase (NOS) substrate L-arginine to produce chlorinated L-arginine (cl-L-Arg). Interestingly, cl-L-Arg potently inhibits the formation of NO metabolites in cultured endothelial cells. It is unknown whether cl-L-Arg has a direct inhibitory effect on endothelial NOS (eNOS). In addition, the effect of cl-L-Arg on the other NOS isoforms, neuronal NOS (nNOS) and inducible NOS (iNOS), is also unknown. Therefore, we designed the current study to test the effects of cl-L-Arg on eNOS, nNOS, and iNOS. Using recombinant NOS, we found that cl-L-Arg had a direct inhibitory effect on the activity of NOS. The effect of cl-L-Arg on NOS activity is nonselective, as all three NOS isoforms were inhibited with a similar IC(50). We further determined the effect of cl-L-Arg on the three NOS isoforms at the tissue level. The results demonstrated that cl-L-Arg potently inhibited all three NOS isoform-mediated vessel reactivities, as well as the NOS signaling molecule cGMP. Cl-L-Arg might serve as a novel endogenous NOS inhibitor and an important mediator for vascular dysfunction under inflammatory conditions such as atherosclerosis. Blocking cl-L-Arg formation may be a new therapeutic approach to cardiovascular diseases.     

Therapeutic administration of nitric oxide synthase inhibitors reverses hyperalgesia but not inflammation in a rat model of polyarthritis

Nitric oxide (NO) has been postulated to play a role in pain as well as in inflammation. In the present studies, the effects of NO synthase (NOS) inhibitors on both pain and inflammation were examined in a rat model of polyarthritis. Female Lewis rats were injected intraperitoneally (i.p.) with peptidoglycan/polysaccharide (PG/PS) or saline to induce arthritis. Hind paw volume, response latency to thermal nociceptive stimulus and mechanical threshold were measured daily for the next 35 days. Paw inflammation, thermal hyperalgesia and mechanical allodynia developed in all rats that received PG/PS compared to saline. On day 19 (chronic inflammation phase), rats were given either N(G)-nitro-L-arginine methyl ester (L-NAME, non-selective NOS inhibitor, 100 mg/l), L-N (6)-(1-iminoethyl) lysine (L-NIL, selective inducible NOS inhibitor, 10 mg/l) or no drug in drinking water. By day 21, L-NAME treatment reversed the thermal hyperalgesia completely and this effect remained until day 35. Similarly, L-NIL treatment reversed thermal hyperalgesia from days 24 to 34. Neither treatment affected mechanical allodynia. Paw volume was not different between PG/PS treated and PG/PS plus L-NAME treated rats. However, the PG/PS plus L-NIL treatment produced an increase in paw volume greater than did PG/PS alone. Other rats were treated with PG/PS plus the antiinflammatory agent indomethacin (days 19-35). Indomethacin treatment reversed all the measured parameters, although the reversal of mechanical allodynia was only partial. These results suggest that NO is involved in thermal, but not mechanical sensory pathways and that the selective inhibition of inducible NOS activity exacerbates established inflammation.     

The importance of leukotrienes in airway inflammation in a mouse model of asthma

Inhalation of antigen in immunized mice induces an infiltration of eosinophils into the airways and increased bronchial hyperreactivity as are observed in human asthma. We employed a model of late-phase allergic pulmonary inflammation in mice to address the role of leukotrienes (LT) in mediating airway eosinophilia and hyperreactivity to methacholine. Allergen intranasal challenge in OVA-sensitized mice induced LTB4 and LTC4 release into the airspace, widespread mucus occlusion of the airways, leukocytic infiltration of the airway tissue and broncho-alveolar lavage fluid that was predominantly eosinophils, and bronchial hyperreactivity to methacholine. Specific inhibitors of 5- lipoxygenase and 5-lipoxygenase-activating protein (FLAP) blocked airway mucus release and infiltration by eosinophils indicating a key role for leukotrienes in these features of allergic pulmonary inflammation. The role of leukotrienes or eosinophils in mediating airway hyperresponsiveness to aeroallergen could not be established, however, in this murine model.     

Oxidant stress in rat liver after lipopolysaccharide administration: effect of inducible nitric-oxide synthase inhibition

The role of inducible nitric-oxide synthase (iNOS) in lipopolysaccharide (LPS)-induced hepatic oxidant stress was evaluated using the iNOS inhibitor L-iminoethyl-lysine (L-NIL). Male rats were divided into three groups. One group received LPS (Salmonella minnesota) 2 mg/kg i.v. A second group received LPS plus L-NIL (3 mg/kg i.p.) at the time of LPS administration followed by a second dose 3 h later. A third group received saline i.v. At 6 h, blood and liver tissue were collected. Serum nitrate/nitrite (metabolic products of nitric oxide) levels were increased from 5.4 +/- 1.5 nmol/ml in the saline group to 360 +/- 48 nmol/ml in the LPS group (n = 5). Values for the LPS + L-NIL group were significantly reduced to 35 +/- 7 nmol/ml. Tissue malondialdehyde levels were increased from 0.20 +/- 0.02 nmol/mg (n = 4) in the saline group to 0.41 +/- 0.03 nmol/mg (n = 4) in the LPS group. L-NIL significantly reduced the values in the LPS group to 0.29 +/- 0.02 nmol/mg (n = 4). 4-Hydroxynonenal-protein adducts levels were increased 3.6-fold by LPS treatment as compared with saline. L-NIL significantly reversed the levels to 1.6-fold (n = 4). Intracellular GSH levels were decreased from 8.49 +/- 0.64 nmol/mg (n = 4) in the saline group to 5.63 +/- 0.51 nmol/mg in the LPS group (n = 7). L-NIL significantly increased the levels in the LPS group to 7.04 +/- 0.46 nmol/mg (n = 7). These data indicate that LPS-induced nitric oxide generation can result in oxidant stress in the liver, and that inhibitors of iNOS may offer some protection in LPS-induced hepatic toxicity.     

Fas-positive T cells regulate the resolution of airway inflammation in a murine model of asthma

Persistent airway inflammation, mucus production, and airway hyperreactivity are the major contributors to the frequency and severity of asthma. Why lung inflammation persists in asthmatics remains unclear. It has been proposed that Fas-mediated apoptosis of inflammatory cells is a fundamental mechanism involved in the resolution of eosinophilic airway inflammation. Because infiltrating eosinophils are highly sensitive to Fas-mediated apoptosis, it has been presumed that direct ligation of Fas on eosinophils is involved. Here, we utilize adoptive transfers of T cells to demonstrate that the delayed resolution of eosinophilia in Fas-deficient mice is a downstream effect of Fas deficiency on T cells, not eosinophils. Interestingly, the mice that received Fas-deficient T cells, but not the controls, developed a persistent phase of inflammation that failed to resolve even 6 wk after the last challenge. This persistent phase correlated with decreased interferon (IFN)gamma production by Fas-deficient T cells and could be reproduced with adoptive transfer of IFNgamma-deficient T cells. These data demonstrate that Fas deficiency on T cells is sufficient for the development of long-term allergic airway disease in mice and implies that deregulation of death receptors such as Fas on human T cells could be an important factor in the development and/or chronic nature of asthma.     

Characterisation of ultraviolet-B-induced inflammation as a model of hyperalgesia in the rat

In humans, the acute inflammatory reaction caused by ultraviolet (UV) radiation is well studied and the sensory changes that are found have been used as a model of cutaneous hyperalgesia. Similar paradigms are now emerging as rodent models of inflammatory pain. Using a narrowband UVB source, we irradiated the plantar surface of rat hind paws. This produced the classical feature of inflammation, erythema, and a significant dose-dependent reduction in both thermal and mechanical paw withdrawal thresholds. These sensory changes peaked 48h after irradiation. At this time there is a graded facilitation of noxious heat evoked (but not basal) c-fos-like immunoreactivity in the L4/5 segments of the spinal cord. We also studied the effects of established analgesic compounds on the UVB-induced hyperalgesia. Systemic as well as topical application of ibuprofen significantly reduced both thermal and mechanical hyperalgesia. Systemic morphine produced a dose-dependent and naloxone sensitive reversal of sensory changes. Similarly, the peripherally restricted opioid loperamide also had a dose-dependent anti-hyperalgesic effect, again reversed by naloxone methiodide. Sequestration of NGF, starting at the time of UVB irradiation, significantly reduced sensory changes. We conclude that UVB inflammation produces a dose-dependent hyperalgesic state sensitive to established analgesics. This suggests that UVB inflammation in the rat may represent a useful translational tool in the study of pain and the testing of analgesic agents.     

Protein kinase C mediates lipopolysaccharide- and phorbol-induced nitric-oxide synthase activity and cellular injury in the rat colon

The role of protein kinase C (PKC) in lipopolysaccharide (LPS)- and phorbol ester-induced changes in rat colonic cellular integrity and Ca(2+)-independent inducible nitric-oxide synthase (iNOS) activity was investigated. LPS treatment (3 mg kg(-1) i.p.) increased colonic cellular PKC activity within 1 h after administration. The percentage of nonviable cells and iNOS activity in response to LPS were reduced by pretreatment with the selective PKC antagonist GF 109203X (25 ng kg(-1) i.v.). Pretreatment with the selective iNOS inhibitor 1400W (5 mg kg(-1) s.c.) reduced the extent of cellular injury and iNOS activity but did not affect the increase in LPS-mediated PKC activation. Reduction of circulating neutrophils with anti-neutrophil serum reduced cell damage as well as the increases in PKC and iNOS activities in response to LPS. Intracolonic administration of the phorbol ester phorbol-12-myristate-13-acetate (PMA; 3 mg kg(-1)) increased colonic cellular PKC activity within 2 h after instillation. Cellular iNOS activity did not increase until 6 h after PMA administration. The colonic responses to PMA were eliminated by GF 109203X. The selective iNOS inhibitor 1400W reduced the increase in cell injury but did not affect the PKC activation in response to PMA. LPS treatment also increased in the proteins for PKC-alpha, PKC-delta, PKC-epsilon, and PKC-zeta. PMA treatment resulted in PKC-delta and PKC-epsilon translocation from cytosol to membrane. These data suggest that PKC mediates iNOS activation and subsequent colonic cell injury in response to LPS administration. The delta- and epsilon-isozymes appear to be most closely associated with these responses.     

CD8+ T cells are involved in early inflammation before macrophages in a rat adipose tissue engineering chamber model

Adipose tissues regenerated using tissue engineering chambers (TECs) show the potential for applications in reconstruction of soft tissue defects. Previous studies have shown that early inflammation plays a key role in angiogenesis and adipogenesis required for adipose tissue generation. However, the sequence of events of the early inflammatory cascade is unclear. In this study, we investigated the role of early inflammatory cells in adipose tissue engineering using a rat TEC model. Rats in the TEC model were divided into five groups: the control group, the zymosan A‐treated group, the 5‐AIQ‐treated group, the imatinib‐treated group, and the CD8+ T cell injection group. Fat pad volume, angiogenesis, adipogenesis, inflammatory factor levels, and inflammatory cell infiltration in chambers after implantation were evaluated at different time points. The volume of fat pads of was higher in the zymosan A‐treated and CD8+ T cell injection groups than other groups, and these two groups also showed higher levels of proinflammatory factors, greater numbers of CD31+ cells and perillipin+/Ki67+ cells, and higher macrophage infiltration. The infiltration of CD8+ T cell peaked at 3 days after implantation, which was earlier than that of macrophages. However, inhibition of CD8+ T cells reduced the recruitment of macrophages and lowered inflammation in the TECs. CD8+ T cells played a key role in promoting inflammation at earlier stages than macrophages in adipose TECs. Increased levels of interleukin‐2 secretion by CD8+ T cells resulted in recruitment of more infiltrating macrophages to enhance inflammation, as required for adipose tissue regeneration.     

Serine protease activity of Per a 10 augments allergen-induced airway inflammation in a mouse model

Background We recently reported an immunodominant serine protease allergen (Per a 10) from Periplaneta americana. This study investigates the role of its proteolytic activity in driving the immune responses towards self and other allergens. Materials and methods Groups of Balb/c mice were sensitized intraperitoneally and subcutaneously with proteolytically active Per a 10 or inactivated Per a 10 (using aminoethyl benzenesulfonyl fluoride hydrochloride) or whole body P. americana extract and subsequently challenged intranasally with the respective antigens. Mice were also sensitized and challenged with ovalbumin (OVA) alone or co‐administered with active or inactive Per a 10. The immune‐inflammatory responses were measured by airway hyperresponsiveness (AHR) and cellular infiltration of lungs i.e. eosinophil counts, eosinophil peroxidase (EPO) activity, myeloperoxidase activity (MPO), lung histopathology, serum levels of specific‐antibodies and levels of Th1/Th2 interleukins in bronchoalveolar lavage fluid (BALF) and in spleen cells culture supernatant. Results Mice challenged with active Per a 10/P. americana extract showed a significant airway inflammation demonstrated by enhanced AHR and increased cellular infiltration of lungs as evidenced by high eosinophil counts, EPO activity, IL‐4 and IL‐5 in BALF. Active Per a 10 also induced a significant proliferation of spleen cells, increased secretion of IL‐4 and IL‐5 in the spleen cells culture supernatant and systemic production of specific‐IgE and IgG1. However, exposure with inactive Per a 10 elicited a low cellular infiltration and systemic antibody production. Exposure to OVA with active Per a 10 demonstrated a significantly high cellular infiltration and production of OVA‐specific IgE and IgG1, than exposure to OVA alone or with inactive Per a 10. Conclusions Proteolytic activity of Per a 10 plays an important role in driving the allergic immune response by providing an adjuvant effect, towards self and other potential allergens present in the same microenvironment.