• 제목, 요약, 키워드: iNOS

검색결과 1,525건 처리시간 0.037초

Endotoxin-induced renal tolerance against ischemia and reperfusion injury is removed by iNOS, but not eNOS, gene-deletion

  • Kim, Jee-In;Jang, Hee-Seong;Park, Kwon-Moo
    • BMB Reports
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    • v.43 no.9
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    • pp.629-634
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    • 2010
  • Endotoxin including lipopolysaccharide (LPS) confers organ tolerance against subsequent challenge by ischemia and reperfusion (I/R) insult. The mechanisms underlying this powerful adaptive defense remain to be defined. Therefore, in this study we attempted to determine whether nitric oxide (NO) and its associated enzymes, inducible NOS (iNOS) and endothelial NOS (eNOS, a constitutive NOS), are associated with LPS-induced renal tolerance against I/R injury, using iNOS (iNOS knock-out) or eNOS (eNOS knock-out) gene-deleted mice. A systemic low dose of LPS pretreatment protected kidney against I/R injury. LPS treatment increased the activity and expression of iNOS, but not eNOS, in kidney tissue. LPS pretreatment in iNOS, but not eNOS, knock-out mice did not protect kidney against I/R injury. In conclusion, the kidney tolerance to I/R injury conferred by pretreatment with LPS is mediated by increased expression and activation of iNOS.

Pretreatment of Macrophages with Paclitaxel Inhibits iNOS Expression

  • Li Mei-Hong;Kang Jong-Soon;Kim Hwan-Mook;Jeon Young-Jin
    • Toxicological Research
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    • v.22 no.2
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    • pp.103-107
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    • 2006
  • We demonstrate that paclitaxel, an antitumor agent derived from yew tree, inhibits LPS-induced expression of iNOS gene in RAW 264.7 cells. Previously, paclitaxel has been known to induce iNOS gene expression in macrophages. However, in this report we described that the pre-treatment of macrophages with paclitaxel ($0.1{\mu}M$) for 8 h inhibited LPS-induced iNOS gene expression. Pretreatment of RAW 264.7 cells with paclitaxel significantly inhibited LPS-stimulated nitric oxide (NO) production. Western immunoblot of iNOS and RT-PCR analysis showed that the decrease of NO was due to the inhibition of iNOS gene expression in RAW 264.7 cells. Immunocytochemical staining of iNOS further confirmed that pretreatment of macrophages with paclitaxel inhibited macrophage activation. Electrophoretic mobility shift assay showed that paclitaxel inhibited $NF-_{\kappa}/Rel$ DNA binding. Collectively, these series of experiments indicate that paclitaxel inhibits iNOS gene expression by blocking $NF-_{\kappa}B/Rel$ activation.

Alteration of Nitric Oxide Synthase and Guanylyl Cyclase Activity in Rats with Ischemia/Reperfusion Renal Injury

  • Bae, Eun-Hui;Kim, Soo-Wan
    • The Korean Journal of Physiology and Pharmacology
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    • v.10 no.6
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    • pp.337-341
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    • 2006
  • The present study was designed to investigate the protein expression of nitric oxide synthase (NOS) and guanylyl cyclase (GC) activity in ischemia/perfusion (I/R) renal injury in rats. Renal I/R injury was experimentally induced by clamping the both renal pedicle for 40 min in Sprague-Dawley male rats. The renal expression of NOS isoforms was determined by Western blot analysis, and the activity of guanylyl cyclase was determined by the amount of guanosine 3', 5'-cyclic monophosphate (cGMP) formed in response to sodium nitroprusside (SNP), NO donor. I/R injury resulted in renal failure associated with decreased urine osmolality. The expression of inducible NOS (iNOS) was increased in I/R injury rats compared with controls, while endothelial NOS (eNOS) and neuronal NOS (nNOS) expression was decreased. The urinary excretion of NO metabolites was decreased in I/R injury rats. The cGMP production provoked by SNP was decreased in the papilla, but not in glomerulus. These results indicate an altered regulation of NOS expression and guanylyl cyclase activity in I/R-induced nephropathy.

Gold Sodium Thiomalate에 의한 유도성 Nitric Oxide Synthase Gene의 발현억제: Gold 제제와 Sodium Salicylate의 차이점 (Gold Sodium Thiomalate Inhibits iNOS Gene Expression in RAW 264.7 Macrophage: Differential Regulation by Gold Sodium Thiomalate and Sodium Salicylate)

  • 임종호;배진영
    • Biomolecules & Therapeutics
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    • v.10 no.4
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    • pp.230-235
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    • 2002
  • Gold sodium thiomalate (GST, gold compound) is a widely used anti-arthritic, anti-rheumatic and anti-inflammatory drug that is considered a good alternative to sodium salicylate (NaSA) for individuals who cannot tolerate salicylates. Nitric oxide (NO) synthesized by inducible nitric oxide synthase (iNOS) has been implicated as a mediator of inflammation. Recent evidence suggests that anti-inflammatory effect of NaSA lies in the inhibition of iNOS, but nothing has been reported about the direct effect of iNOS expression by GST. The present study was designed to elucidate sequentially the action mechanisms of GST and NaSA on lipopolysaccharide (LPS) plus interferon-gamma (IFN-$\gamma$) induced iNOS expression in RAW 264.7 macrophages. Both GST and NaSA inhibited NO production and iNOS protein expression in a dose dependent manner. GST inhibited iNOS mRNA expression induced by LPS plus IFN-$\gamma$, whereas NaSA did not. These findings suggest that GST may exert anti-arthritic, anti-rheumatic and anti-inflammatory effect by inhibiting iNOS expression induced by LPS plus IFN-$\gamma$ at transcriptional level, whereas NaSA exert its effect by inhibiting iNOS expression at the translational or posttranslational level.

Inhibitory Effect of Esculetin on the Inducuble Nitric Oxide Synthase Expression in TNF-stimulated 3T3-L1 Adipocytes

  • Yang, Jeong-Yeh
    • The Korean Journal of Physiology and Pharmacology
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    • v.7 no.5
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    • pp.283-287
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    • 2003
  • While nitric oxide (NO) produced by inducible nitric oxide synthase (iNOS) is beneficial for host survival, it is also detrimental to the host. Thus, regulation of iNOS gene expression may be an effective therapeutic strategy for the prevention of unwanted reactions at various pathologic conditions. During the screening process for the possible iNOS regulators, we observed that esculetin is a potent inhibitor of cytokine-induced iNOS expression. The treatment of 3T3-L1 adipocytes with the tumor necrosis factor-${\alpha}$ (TNF) induced iNOS expression, leading to enhanced NO production. TNF-induced NO production was inhibited by esculetin in a dose-dependent manner. Esculetin inhibited the TNF-induced NO production at the transcriptional level through suppression of iNOS mRNA and subsequent iNOS protein expression. These results suggest esculetin, a component of natural products, as a naturally occurring, nontoxic means to attenuate iNOS expression and NO-mediated cytotoxicity.

Protein Kinase $C-{\alpha}$ Regulates Toll-like Receptor 4-Mediated Inducible Nitric Oxide Synthase Expression

  • Lee, Jin-Gu;Chin, Byung-Rho;Baek, Suk-Hwan
    • Journal of the Korean Association of Oral and Maxillofacial Surgeons
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    • v.34 no.1
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    • pp.28-35
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    • 2008
  • Purpose: The nitric oxide (NO) release by inducible nitric oxide synthase (iNOS) is the key events in macrophage response to lipopolysaccharide (LPS) which is suggested to be a crucial mediator for inflammatory and innate immune responses. NO is an important mediator involved in many host defense action and may also lead to a harmful host response to bacterial infection. However, given the importance of iNOS in a variety of pathophysiological conditions, control of its expression and signaling events in response to LPS has been the subject of considerable investigation. Materials and Methods: The Raw264.7 macrophage cell line was used to observe LPS-stimulated iNOS expression. The expression of iNOS is observed by Western blot analysis and real-time RT-PCR. Protein kinase C $(PKC)-{\alpha}$ overexpressing Raw264.7 cells are established to determine the involvement of $PKC-{\alpha}$ in LPS-mediated iNOS expression. $NF-{\kappa}B$ activity is measured by $I{\kappa}B{\alpha}$ degradation and $NF-{\kappa}B$ luciferase activity assay. Results: We found that various PKC isozymes regulate LPS-induced iNOS expression at the transcriptional and translational levels. The involvement of $PKC-{\alpha}$ in LPS-mediated iNOS induction was further confirmed by increased iNOS expression in $PKC-{\alpha}$ overexpressing cells. $NF-{\kappa}B$ dependent transactivation by LPS was observed and $PKC-{\alpha}$ specific inhibitory peptide abolished this activation, indicating that $NF-{\kappa}B$ activation is dependent on $PKC-{\alpha}$. Conclusion: Our data suggests that $PKC-{\alpha}$ is involved in LPS-mediated iNOS expression and that its downstream target is $NF-{\kappa}B$. Although $PKC-{\alpha}$ is a crucial mediator in the iNOS regulation, other PKC isozymes may contribute LPS-stimulated iNOS expression. This finding is needed to be elucidated in further study.

Magnolol Inhibits iNOS, p38 Kinase, and NF-κB/Rel in Murine Macrophages

  • Li Mei Hong;Chang In-Youp;Youn Ho-Jin;Jang Dae-Sik;Kim Jin-Sook;Jeon Young-Jin
    • Toxicological Research
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    • v.22 no.3
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    • pp.293-299
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    • 2006
  • We demonstrate that magnolol, a hydroxylated biphenyl compound isolated from Magnolia officinalis, inhibits LPS-induced expression of iNOS gene in RAW 264.7 cells(murine macrophage cell line). Treatment of RAW 264.7 cells with magnolol inhibited LPS-stimulated nitric oxide production in a dose-related manner. RT-PCR analysis showed that the decrease of NO was due to the inhibition of iNOS gene expression. Western immunoblot analysis of phosphorylate p38 kinase showed magnolol significantly inhibited the phosphorylation of p38 kinase which is important in the regulation of iNOS gene expression. The specific p38 inhibiter SB203580 abrogated the LPS-induced NO generation and iNOS expression, whereas the selective MEK-1 inhibitor PD98059 did not affect the NO induction. Immunostaining of p65 and reporter gene assay showed that magnolol inhibited NF-${\kappa}/Rel$ nuclear translocation and transcriptional activation, respectively. Collectively, this series of experiments indicates that magnolol inhibits iNOS gene expression by blocking NF-k/Rel and p38 kinase signaling. Due to the critical role that NO release plays in mediating inflammatory responses, the inhibitory effects of magnolol or iNOS suggest that magnolol may represent a useful anti-inflammatory agent.

금은화의 NF-${\kappa}B$ 활성 억제를 통한 iNOS 조절이 NC/Nga 생쥐의 아토피 피부염에 미치는 영향 (Lonicera Japonica Inhibits Atopy Dermatitis in NC/Nga Mouse through Regulation of iNOS by NF-${\kappa}B$ Suppression)

  • 안상현;김호현
    • 동의생리병리학회지
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    • v.24 no.2
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    • pp.278-283
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    • 2010
  • Inducible nitric oxide synthase (iNOS) are important inflammation enzyme and severe up-nitric oxide (NO) production by this enzyme has been intricate with pathogenesis of atopy dermatitis. The present study was designed in order to determine whether Lonicera japonica could inhibit atopy dermatitis through modulation of iNOS by NF-${\kappa}B$ suppression. We found that IKK mRNA and iNOS mRNA expression in RAW 264.7 macrophages stimulated with lipopolysaccharide dose-dependantly decreased by Lonicera japonica (0.4 - 1.0 mg/$m{\ell}$) and NO production decreased. The distribution of NF-${\kappa}B$ p65 and iNOS positive reacted cell in NC/Nga mice with atopy dermatitis were decreased by Lonicera japonica (45 mg/kg/day) and apoptosis were increased. These data likely indicate that Lonicera japonica may act as inflammatory regulator for atopy dermatitis through iNOS modulation by NF-${\kappa}B$B suppression and may be possible to develop useful agent for chemoprevention of NO intricate inflammatory diseases.

Diclofenac Inhibits $IFN-{\gamma}$ Plus Lipopolysaccharide-Induced iNOS Gene Expression via Suppression of $NF-{\kappa}B$ Activation in RAW 264.7 Macrophages

  • Bae, So-Hyun;Ryu, Young-Sue;Hong, Jang-Hee;Park, Jin-Chan;Kim, Yong-Man;Seok, Jeong-Ho;Lee, Jae-Heun;Hur, Gang-Min
    • The Korean Journal of Physiology and Pharmacology
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    • v.5 no.6
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    • pp.521-527
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    • 2001
  • Diclofenac, a phenylacetic acid derivative, is a widely used non-steroidal anti-inflammatory drug (NSAID) to provide effective relief of inflammation and pain. Nitric oxide (NO) synthesized by inducible nitric oxide synthase (iNOS) has been implicated as a mediator of inflammation. We examined the inhibitory effects of diclofenac on the induction of iNOS in RAW 264.7 macrophages which were activated with lipopolysaccharide (LPS) plus interferon-gamma $(IFN-{\gamma}).$ Treatment of RAW 264.7 cells with diclofenac and other NSAIDs (aspirin and indomethacin) significantly inhibited NO production and iNOS protein expression induced by LPS plus $IFN-{\gamma}.$ Also, diclofenac but not aspirin and indomethacin, inhibited iNOS mRNA expression and nuclear factor-kappa B $(NF-{\kappa}B)$ binding activity concentration-dependently. Furthermore, transfection of RAW 264.7 cells with iNOS promoter linked to a CAT reporter gene revealed that only diclofenac inhibited the iNOS promoter activity induced by LPS plus $IFN-{\gamma}$ through the $NF-{\kappa}B$ sites of iNOS promoter. Taken together, these suggest that diclofenac may exert its anti-inflammatory effect by inhibiting iNOS gene expression at the transcriptional level through suppression of $NF-{\kappa}B$ activation.

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Deficiency of iNOS Does Not Prevent Isoproterenol-induced Cardiac Hypertrophy in Mice

  • Cha, Hye-Na;Hong, Geu-Ru;Kim, Yong-Woon;Kim, Jong-Yeon;Dan, Jin-Myoung;Park, So-Young
    • The Korean Journal of Physiology and Pharmacology
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    • v.13 no.3
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    • pp.153-159
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    • 2009
  • We investigated whether deficiency of inducible nitric oxide synthase (iNOS) could prevent isoproterenol-induced cardiac hypertrophy in iNOS knockout (KO) mice. Isoproterenol was continuously infused subcutaneously (15 mg/kg/day) using an osmotic minipump. Isoproterenol reduced body weight and fat mass in both iNOS KO and wild-type mice compared with saline-infused wild-type mice. Isoproterenol increased the heart weight in both iNOS KO and wild-type mice but there was no difference between iNOS KO and wild-type mice. Posterior wall thickness of left ventricle showed the same tendency with heart weight. Protein level of iNOS in the left ventricle was increased in isoproterenol-infused wild-type mice. The gene expression of interleukin-6 (IL-6) and transforming growth factor-${\beta}$ (TGF-${\beta}$) in isoproterenol-infused wild-type was measured at 2, 4, 24, and 48-hour and isoproterenol increased both IL-6 (2, 4, 24, and 48-hour) and TGF-${\beta}$ (4 and 24-hour). Isoproterenol infusion for 7 days increased the mRNA level of IL-6 and TGF-${\beta}$ in iNOS KO mice, whereas the gene expression in wild-type mice was not increased. Phosphorylated form of extracellular signal-regulated kinases (pERK) was also increased by isoproterenol at 2 and 4-hour but was not increased at 7 days after infusion in wild-type mice. However, the increased pERK level in iNOS KO mice was maintained even at 7 days after isoproterenol infusion. These results suggest that deficiency of iNOS does not prevent isoproterenol-induced cardiac hypertrophy and may have potentially harmful effects on cardiac hypertrophy.