The expression and activity of renal nitric oxide synthase and circulating nitric oxide in polycystic kidney disease rats

Nitric oxide (NO) influences tubular fluid and electrolyte transport, and hence possibly also fluid accumulation in renal cysts. The expression and activity of intrarenal constitutive NO synthase (cNOS) [neuronal NOS, nNOS and endothelial NOS, eNOS] and inducible NOS (iNOS) and plasma nitrite/nitrate (PNOx) concentration were assessed in homozygous Han:SPRD polycystic kidney disease (PKD) rats (cy/cy), heterozygous Han:SPRD PKD rats (cy/+), homozygous normal Han:SPRD littermates (+/+) and Sprague Dawley rats (sd). The results showed: 1) nNOS expression was decreased in proximal tubules and thick ascending limbs of the loop of Henle in cy/cy and cy/+ rats compared to +/+ and sd rats (p<0.05). nNOS was weakly expressed in the epithelium of small cysts and unexpressed in epithelium of large cysts. 2) iNOS expression was increased in proximal tubular epithelial cells in cy/+ rats compared to +/+ rats and sd rats (p<0.01). iNOS expression in cyst epithelium was decreased in cy/+ rats (p<0.05) and absent in cy/cy rats. 3) eNOS expression was similar in the endothelium of intrarenal arteries in all groups. 4) The activity of renal cNOS was decreased in cy/cy and cy/+ rats; the activity of iNOS was decreased only in cy/cy rats, with no significant difference among the other three groups. 5) PNOx concentration was higher in cy/cy rats than in the other three groups, and correlated positively with plasma creatinine and urea. In conclusion, NOS expression and activity decreased as cysts developed, suggesting that NO downregulation is involved in the pathogenesis of PKD.     

Time-course of neuropathic pain in mice deficient in neuronal or inducible nitric oxide synthase

Nitric oxide which is synthesised by nitric oxide synthase (NOS) is involved in processes related to regeneration after nerve injury and neuropathic pain. Here we investigated functional aspects of the nociceptive system. For that purpose, the chronic constriction injury (CCI) model induced by loose ligation of the sciatic nerve was employed in C57Bl/6J wild-type (WT), nNOS and iNOS knock-out (−/−) mice. Their thermal and mechanical pain thresholds were then measured over a period of six weeks. In addition, ³H-DAMGO, ³H-CP 55.940, and ³H-l-glutamate binding, and neuronal (NeuN-immunostained) and astroglial (GFAP-immunostained) cell composition were studied. There were no significant differences in cell composition between the three strains used. Significant differences between CCI and sham-operated animals were found in nNOS−/− after day 6, in WT mice after day 10, and in iNOS−/− after day 17 post surgery. The mechanical pain threshold was normalised after day 45 post surgery in WT mice only. There were no changes in DAMGO and glutamate binding. However, we found significant differences in CP 55.940 binding in the spinal cord. It was concluded that NOS–cannabinoid interaction contributes to differences in nociceptive behaviour.     

巨噬细胞诱导型一氧化氮合酶的表达调节机制

一氧化氮是一种重要的巨噬细胞免疫效应分子,它参与免疫调节和宿主防御反应.一氧化氮的生成主要由诱导型一氧化氮合酶调节,然而诱导型一氧化氮合酶表达的调节机制及信号通路尚不完全清楚.     

依普利酮对高盐诱导的高血压大鼠主动脉内皮型一氧化氮合酶表达及活性的影响

目的:探讨依普利酮对高盐诱导的高血压大鼠主动脉内皮型一氧化氮合酶(e NOS)的表达及活性的影响。方法:50~60 g 4周龄雄性Wistar大鼠随机分为3组:对照(control,C)组用普通饲料饲养16周,高盐饮食(high salt diet,HS)组及依普利酮(eplerenone,Epl)组用5%高盐饲料饲养16周,C组和HS组于末4周给予同等剂量生理盐水灌胃,而Epl组于末4周给予依普利酮40 mg·kg-1·d-1灌胃。每2周检测各组大鼠尾动脉收缩压,16周后处死大鼠,留取主动脉。ELISA法检测醛固酮含量,蛋白免疫印迹法检测盐皮质激素受体(MR)及e NOS蛋白表达水平,化学比色法测定一氧化氮合酶活性,免疫组化染色法观察主动脉e NOS、神经型一氧化氮合酶(n NOS)及MR蛋白表达与定位。结果:(1)高盐饲料饲养8周后,大鼠收缩压即明显升高,并逐渐上升,16周时HS组收缩压较同时点C组明显升高(P0.05);依普利酮灌胃4周后,收缩压比灌胃前明显下降(P0.05)。(2)与C组比较,HS组、Epl组主动脉醛固酮含量明显增加(P0.05),且MR表达明显增加(P0.05)。(3)HS组较C组e NOS蛋白表达减少(P0.05)、结构型一氧化氮合酶(c NOS)活性也降低(P0.05);Epl组较HS组e NOS蛋白表达增加(P0.05)、c NOS活性增高(P0.05)。结论:(1)高盐诱导高血压大鼠的主动脉醛固酮含量明显增加,醛固酮可能通过激动MR降低主动脉e NOS蛋白表达及酶活性。(2)选择性MR拮抗剂依普利酮可恢复e NOS蛋白表达及活性,改善e NOS功能。     

内皮型、诱导型一氧化氮合酶在乳腺癌中的表达

目的 :研究内皮型一氧化氮合酶 (eNOS)、诱导型一氧化氮合酶 (iNOS)在乳癌中表达及与淋巴结转移的关系。方法 :采用免疫组化S P法检测 60例乳癌中eNOS和iNOS的表达。结果 :eNOS和iNOS阳性在乳癌中表达率分别为 75 0 %和71 7%。在淋巴结转移组和无淋巴结转移组中eNOS阳性表达率分别为 66 7%和 83 3 % ,两组间差异无统计学意义 (χ2 =2 2 2 ,P >0 0 5) ,而iNOS在淋巴结转移和无转移组中阳性表达率分别为 53 3 %和 90 0 % ,两组间差异有统计学意义 (χ2 =9 93 ,P <0 0 1 )。结论 :内皮型、诱导型一氧化氮合酶在乳腺癌中高表达 ;iNOS的表达与乳腺癌的淋巴转移相关     

Adiponectin activates endothelial nitric oxide synthase through AMPK signaling after subarachnoid hemorrhage

Adiponectin is produced from fatty tissue and has been reported to be involved with metabolic syndrome. Recently, adiponectin has been demonstrated to play a neuroprotective role against cerebral ischemia. In this study, we explored the time-course serial expression changes of adiponectin in cerebrospinal fluid (CSF) after subarachnoid hemorrhage (SAH) and the effects of adiponectin on cerebral arteries. The concentrations of adiponectin were measured serially until day 14 in CSF of 8 patients with SAH. The CSF samples obtained from 6 patients suffering from an unruptured aneurysm were used as controls. Serum samples were collected from 6 healthy adult volunteers. Rat cerebral arteries were incubated with adiponectin (2μg/ml). Western blot analysis using AMP-activated protein kinase α (AMPKα), phosphorylated (p)-AMPKα at Thr(172), endothelial nitric oxide synthase (eNOS), p-eNOS at Ser(1177) and actin antibodies was then performed. The adiponectin concentrations in serum and control CSF were 17,670±3748ng/ml and 9.2±3.0ng/ml, respectively. After SAH, the concentration of adiponectin in the CSF significantly increased on the first post-SAH day and gradually decreased thereafter. Adiponectin significantly phosphorylated both the AMPKα and eNOS of the cerebral arteries. Our findings suggest that adiponectin is significantly increased in the CSF after SAH, resulting in the activation of AMPKα and eNOS. Adiponectin plays an important role against cerebral vasospasm via the AMPK/eNOS signaling pathway.     

兔动脉粥样硬化形成过程中血清NOS活性的变化

目的研究兔动脉粥样硬化形成过程中血一氧化氮合酶(NOS)活性的变化及其作用。方法将30只长耳白兔随机分为3组:普通饮食组、高脂饮食组、球囊损伤 高脂饮食组,每组10只,3个月后以中国斑点蝰蛇毒和组胺触发使斑块破裂。生化监测血脂、血清NO、NOS及OH-水平,病理检查动脉硬化斑块。结果高脂饮食组、球囊损伤 高脂饮食组血脂水平明显增高;血清NO水平在药物触发及斑块破裂后明显减少;NOS活性及OH-水平在高脂喂养后明显升高,药物触发后明显减少。结论动脉粥样硬化早期NOS活性增强,内皮功能得到代偿;斑块处于不稳定状态时,NOS活性明显下降,内皮功能明显受损进入失代偿状态。     

Eupartoium makinoi suppresses lipopolysaccharide-induced inducible nitric oxide synthase and cyclooxygenase-2 expression

Inflammation is involved in numerous diseases including cancer. Inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) play important roles in the development of certain inflammatory diseases. Eupatorium makinoi, which belongs to a family of Asteraceae plants, is used medicinally in East Asia. We investigated the effects of an ethanol extract of E. makinoi (EEM) on nuclear factor-kappa B (NF-κB) activation and the expression of iNOS and COX-2 with lipopolysaccharide (TLR4 agonist) in murine macrophages. EEM suppressed NF-κB activation and iNOS and COX-2 expression induced by LPS. These results suggest that EEM may regulate TLR4 signalling pathways and this may be a useful strategy for anti-inflammatory therapies.     

Aster yomena suppresses LPS-induced cyclooxygenase-2 and inducible nitric oxide synthase expression

Inflammation is a pathological process that is known to be involved in numerous diseases. Microbial infection or tissue injury activates inflammatory responses, resulting in the induction of proinflammatory proteins including cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS). Aster yomena is used in traditional Korean remedies to treat cough, asthma, and insect bites. Here, we investigated the effects of A. yomena extract (EAY) on the expression of COX-2 and iNOS induced by LPS. EAY inhibited NF-κB activation and IκBα degradation induced by LPS. EAY suppressed LPS-induced COX-2 and iNOS expression which are the target genes regulated through NF-κB activation in macrophages. EAY also suppressed LPS-induced nitrite production. These results suggest that EAY has the potential to be developed as a potent anti-inflammatory drug.     

Alterations in nitric oxide synthase activity and expression in submandibular glands of NOD mice

The non-obese diabetic (NOD) mouse model of autoimmune sialadenitis offers the possibility of studying the L-arginine/nitric oxide signaling pathway in salivary glands in basal and neurotransmitter-stimulated conditions and, thus, of analyzing the neural control of the secretory process in the target organ. The purpose of this study was to explore putative alterations in the activity and expression of nitric oxide synthase (NOS) in submandibular glands of NOD mice in relation to parotid glands and unrelated tissues. Here we report that NOD mice with incipient signs of secretory dysfunction presented a marked decrease in basal and vasoactive intestinal peptide (VIP)-stimulated NOS activity and a differential expression of NOS I in submandibular glands compared to control BALB/c mice. Similar alterations in NOS I were found in parotid glands but not in brain or spleen of NOD mice. No differences between NOD and controls appeared in NOS II and NOS III expression in any of the tissues studied.     

Human seminal plasma inhibits brain nitric oxide synthase activity

Nitric oxide is a chemical messenger which functions as a neurotransmitteror as a cytotoxic agent. Nitric oxide synthase (NOS) has beenisolated from various mammalian reproductive tissues* The presenceor absence of NOS in spermatozoa has not yet been reported.We therefore tested human and marine spermatozoa for NOS activityby measuring the conversion of argmine to citmlline. No activitywas found either in human or in murine spermatozoa. Human nativesemen and human seminal plasma exerted an inhibition on brainNOS activity, as assayed on rat brain cytosolic fractions. Thisinhibitory effect was dependent on the amount of protein presentin the human seminal plasma. No inhibitory effect was observedwhen homogenates of washed spermatozoa were tested. The humanseminal plasma did not affect the Michaelis constant (Km) ofNOS for L-arginine (endogenous NOS substrate) whereas the maximalvelocity (Vmax) was reduced, suggesting that it contains a non-competitiveinhibitor of brain NOS. This inhibitory component was virtuallyinsensitive to heat; a 10 min treatment to 95°C only slightlyreduced its ability to inhibit brain NOS. The physiologicalrelevance of our observations remains to be elucidated. Humanseminal plasma may exert an inhibition of nitric oxide synthesison cells other than spermatozoa or on cells from the male orfemale genital tract, modulating directly or indirectly (viamodulation of reactive oxygen species formation) the functionalstate of the spermatozoa.     

Differential expression and regulation of inducible nitric oxide synthase (iNOS) mRNA in human trophoblasts in vitro

OBJECTIVES: To determine the expression of inducible nitric oxide synthase (iNOS) in human trophoblast and to examine the possible regulation of iNOS gene by cytokines. MATERIALS AND METHODS: Total RNA was isolated from: 1) homogenized placental tissue; from 2) isolated and purified cytotrophoblast cells; and 3) cytotrophoblast and syncytiotrophoblast cells treated with cytokines in vitro. RNA was reverse transcribed and amplified by polymerase chain reaction, using specific primers for iNOS. Trophoblast cells were treated in vitro by interferon-gamma (IFN-gamma) in a dose of 10 ng/mL, Interleukin 1beta (IL-1beta) (4 ng/mL) and leukemia inhibitory factor (LIF) (1 ng/mL). Trophoblasts were also subjected to immunocytochemistry using iNOS-specific antibody to detect iNOS protein expression in these cells. RESULTS: The expression of iNOS mRNA was found both in placental tissue and isolated cytotrophoblast cells. In culture, the highly differentiated syncytiotrophoblast expressed more mRNA than cytotrophoblast cells. IFN-gamma and LIF, but not IL-1beta, induced iNOS mRNA expression in trophoblast cells in vitro. The effects of these cytokines on iNOS mRNA were only observed in syncytiotrophoblast cells, but not in cytotrophoblast cells. Immunocytochemical staining confirmed the trophoblast cells as a major source of the iNOS synthase production. CONCLUSIONS: 1) Human trophoblast cells are able to express the iNOS mRNA, hence suggesting a role for NO in placental growth and function. 2) LIF and IFN-gamma, but not IL-1beta, induce the iNOS mRNA expression in syncytiotrophoblast cells in vitro, suggesting possible similar regulatory mechanisms in vivo. 3) This study, for the first time, demonstrates the stimulating effect of LIF on iNOS gene expression in human tissue.     

神经型一氧化氮合酶羧基末端PDZ配体在大鼠周围神经损伤后的表达变化

目的:探讨周围神经损伤后神经型一氧化氮合酶羧基末端PDZ配体(carboxy temlinal PDZ ligand of neuronal nitric oxide synthase,CAPON)的表达变化与定位。方法:利用实时荧光定量PCR(real-time fluorescence quantitative PCR,FQPCR)、原位杂交与间接免疫荧光相结合的方法,研究大鼠坐骨神经损伤后CAPON mRNA表达变化及其定位。结果:CAPON mRNA主要分布在正常和损伤坐骨神经的雪旺细胞(Schwann cells,SCs)中,损伤后表达增多,分别在神经夹伤后2周以及切断后1周的近、远侧断端中出现表达高峰。原代培养的SCs中也检测到CAPON的表达,其mRNA分布在核周胞质区域。结论:周围神经损伤后引起CAPON mRNA表达上调,增殖的SCs中表达CA- PON可能对神经损伤后冉生修复发挥一定作用。     

NADPH-diaphorase activity and nitric oxide synthase isoforms in the trophoblast of Calomys callosus

The pattern of expression of a variety of placental nitric oxide synthase isoforms has contributed to elucidating the regulatory mechanisms of nitric oxide (NO) synthesis during gestation. The maintenance of vascular tone, attenuation of vasoconstriction, prevention of platelet and leukocyte adhesion to the trophoblast surface, and possible participation in uterine blood flow seem to be the main functions of NO generated at the fetal-maternal interface in humans and mice. Extending this knowledge to other rodent species commonly used as laboratory animals, in this study we focus on NADPH-diaphorase activity and the distribution of nitric oxide synthase isoforms (NOS) in the trophoblast cells of Calomys callosus during different phases of pregnancy. NADPH-diaphorase activity was evaluated cytochemically and the presence of NOS isoforms detected by immunohistochemistry. These techniques were performed on pre- and postimplantation embryos in situ and in vitro, as well as in placentae on d 14 and 18 of pregnancy. Neither NADPH-diaphorase activity nor inducible or endothelial NOS isoforms were found in pre-implanting embryos except after culturing for at least 48 h, when some of the embryonic cells were positive for the diaphorase reaction. On d 6·5 of pregnancy, trophoblast cells showed intense diaphorase activity both in situ and under in vitro conditions. A positive reaction was also found in the different placental trophoblast cells on d 14 and 18 of pregnancy. The inducible NOS (iNOS) isoform, but not the endothelial isoform, was immunodetected in trophoblast cells from the placenta and from postimplantation embryos in situ and under in vitro conditions. These results strongly suggest the production of NO by the iNOS isoform in the trophoblast of Calomys callosus after embryo implantation. The data also emphasise a possible role for the trophoblast in producing and releasing cytotoxic molecules at the fetal-maternal interface.     

Upregulated expression of N-methyl-D-aspartate receptor 1 and nitric oxide synthase during form-deprivation myopia in guinea pigs

This study aimed to investigate the expression of N-methyl-D-aspartate receptor 1 (NMDAR1) and neuronal constitutive nitric oxide synthase (ncNOS) during form-deprivation myopia (FDM). FDM models were established in guinea pigs with facemasks. NMDAR1 expression in the retina was detected by immunohistochemistry and Western blot analysis. ncNOS mRNA expression was examined by in situ hybridization. cGMP content was measured by radioimmunoassay. In control group, NMDAR1 and ncNOS were expressed in binocular retinas, and there was no significant difference in NMDAR1 and ncNOS expression and cGMP content between the two eyes. However, NMDAR1 and ncNOS expression and cGMP content in the retina of FDM eyes were significantly higher than that of contralateral untreated eyes. Furthermore, ncNOS mRNA level and cGMP content was highly correlated. In conclusion, FDM upregulates the expression of NMDAR1 and ncNOS and increases cGMP content in the retina. NMDAR1/NO-cGMP pathway may contribute to abnormal visual signals during myopic progression.     

Protective role of endothelial nitric oxide synthase

Nitric oxide is a versatile molecule, with its actions ranging from haemodynamic regulation to anti-proliferative effects on vascular smooth muscle cells. Nitric oxide is produced by the nitric oxide synthases, endothelial NOS (eNOS), neural NOS (nNOS), and inducible NOS (iNOS). Constitutively expressed eNOS produces low concentrations of NO, which is necessary for a good endothelial function and integrity. Endothelial derived NO is often seen as a protective agent in a variety of diseases.This review will focus on the potential protective role of eNOS. We will discuss recent data derived from studies in eNOS knockout mice and other experimental models. Furthermore, the role of eNOS in human diseases is described and possible therapeutic intervention strategies will be discussed.     

Expression of nitric oxide synthase and effect of substrate manipulation of the nitric oxide pathway in mouse ovarian follicles

BACKGROUND: Nitric oxide (NO) is a cell messenger with multiple actions in different biological systems, implicated in the control of follicle and oocyte function. NO is formed from L-arginine by isoforms of nitric oxide synthase (NOS) via NG-hydroxy-L-arginine, with L-citrulline as a byproduct. This study aimed to show how modulation of NO by manipulating NOS substrates would affect mouse follicle growth and ovulation in vitro, where vascular effects of NO are attenuated. METHODS: Immunohistochemistry [endothelial (eNOS) and inducible (iNOS)] and in situ hybridization (iNOS) were applied on mouse ovaries. Cultured follicles were also stained for iNOS by immunohistochemistry. For follicles cultured in the presence or absence of L-arginine, the ability of L-citrulline or NG-hydroxy-L-arginine to substitute for L-arginine was assessed in terms of follicle growth and ovulation. RESULTS: iNOS and eNOS were localized in oocytes and theca, with some staining in granulosa. iNOS mRNA occurred predominantly in granulosa and oocyte. Omission of L-arginine significantly reduced follicle survival and ovulation. Partial compensation for L-arginine withdrawal was achieved with L-citrulline and NG-hydroxy-L- arginine. Specific abnormalities of follicle growth were noted. CONCLUSIONS: NOS is present in mouse follicles, and its action is necessary at a local level for normal follicle development in vitro. Reduced growth, persistent basement membranes and reduced ovulation were associated with in vitro disruption of NO.     

诱导型一氧化氮合酶在强啡肽致脊髓损伤中的作用

目的：探讨诱导型一氧化氮合酶（ｉＮＯＳ）在强啡肽致脊髓损伤中的作用。方法：［３Ｈ］－左旋精氨酸转化法测定腹侧和背侧脊髓ｉＮＯＳ活性,原位杂交法观测脊髓ｉＮＯＳｍＲＮＡ表达及其细胞分布。结果：大鼠蛛网膜下腔注射（ＩｎＩ）强啡肽Ａ１－１７（Ｄｙｎ）２０ｎｍｏｌ引起持久性截瘫和迟发性神经元死亡;在Ｄｙｎ致瘫后２～３ｈｉＮＯＳｍＲＮＡ表达开始增多增强,４ｈ达高峰,２４ｈ和４８ｈ仍见广泛表达,其分布以胶质细胞和大运动神经元为主;腹侧脊髓ｉＮＯＳ活性在Ｄｙｎ致瘫后４ｈ显著升高,并持续至２４ｈ和４８ｈ;提前１０ｍｉｎＩｎＩ选择性ｉＮＯＳ抑制剂氨基胍１μｍｏｌ可显著对抗Ｄｙｎ２０ｎｍｏｌ引起的持久瘫及伤后４ｈ腹侧脊髓ｉＮＯＳ活性升高。结论：ｉＮＯＳ持续性高表达与Ｄｙｎ致脊髓损伤机制有关     

Localization of nitric oxide synthase in human trophoblast cells: role of nitric oxide in trophoblast proliferation and differentiation

PROBLEM: There are conflicting reports about the isoform of nitric oxide synthase (NOS) present in trophoblast cells. In this study, we have examined the presence of different NOS isoforms in trophoblast cells. In addition, the role of nitric oxide (NO) in trophoblast function has also been studied by investigating the possible role of nitric oxide in trophoblast proliferation and differentiation. METHOD OF STUDY: NOS isoforms in primary-term trophoblast and JEG-3 cells were identified by immunocytochemistry. The intracellular localization of this enzyme was determined by confocal laser scanning microscopy. Trophoblast proliferation was studied by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrasolium bromide (MTT) conversion assay and cellular differentiation was monitored by human chorionic gonodotropin (hCG) and progesterone secretion, measured by radioimmunoassay. RESULTS: The immunoreactive NOS was present in human trophoblast cells of normal term placenta and JEG-3 cells (a choriocarcinoma cell line) maintained in culture. Nicotinamide adenine dinucleotide phosphate (NADPH)-dependent diaphorase activity overlapped with the immunostaining of NOS. Specific antibodies against the different isoforms of NOS detected the presence of neuronal-type NOS (nNOS) only. The other two isoforms, i.e., eNOS (endothelial) and iNOS (macrophage specific) were completely absent. The nNOS was localized in cell cytoplasm. In culture, JEG-3 cells normally undergo proliferation and cytotrophoblast cells in primary culture differentiate to form hormone-secreting syncytial cells. Sodium nitroprusside (SNP), a nitric oxide donor, when added to the culture, significantly increased proliferation of JEG-3 cells and inhibited the differentiation of cytotrophoblast cells. The arrest by SNP in the formation of syncytial cells was further evidenced by the low secretion profile of hCG and progesterone. CONCLUSIONS: Our findings suggest for the first time the presence of nNOS in the human trophoblast cells and a previously unrecognized role of NO in trophoblast proliferation and differentiation.