scholarly journals Astrovirus-Induced Synthesis of Nitric Oxide Contributes to Virus Control during Infection

2004 ◽  
Vol 78 (3) ◽  
pp. 1564-1574 ◽  
Author(s):  
Matthew D. Koci ◽  
Laura A. Kelley ◽  
Diane Larsen ◽  
Stacey Schultz-Cherry
Keyword(s):  
Nitric Oxide ◽  
Ex Vivo ◽  
Small Animal ◽  
Innate Immune Responses ◽  
Vitro Analysis ◽  
Oxide Synthase ◽  
First Time

ABSTRACT Astrovirus is one of the major causes of infant and childhood diarrhea worldwide. Our understanding of astrovirus pathogenesis trails behind our knowledge of its molecular and epidemiologic properties. Using a recently developed small-animal model, we investigated the mechanisms by which astrovirus induces diarrhea and the role of both the adaptive and innate immune responses to turkey astrovirus type-2 (TAstV-2) infection. Astrovirus-infected animals were analyzed for changes in total lymphocyte populations, alterations in CD4+/CD8+ ratios, production of virus-specific antibodies (Abs), and macrophage activation. There were no changes in the numbers of circulating or splenic lymphocytes or in CD4+/CD8+ ratios compared to controls. Additionally, there was only a modest production of virus-specific Abs. However, adherent spleen cells from infected animals produced more nitric oxide (NO) in response to ex vivo stimulation with lipopolysaccharide. In vitro analysis demonstrated that TAstV-2 induced macrophage production of inducible nitric oxide synthase. Studies using NO donors and inhibitors in vivo demonstrated, for the first time, that NO inhibited astrovirus replication. These studies suggest that NO is important in limiting astrovirus replication and are the first, to our knowledge, to describe the potential role of innate immunity in astrovirus infection.

Abstract 18060: TRAIL Promotes Angiogenesis and Ischemia-Induced Neovascularisation via NOX4, H2O2 and Nitric Oxide-Dependent Mechanisms

Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Belinda A Di Bartolo ◽  
Sian P Cartland ◽  
Leonel Prado-Lourenco ◽  
Nor Saadah M Azahri ◽  
Thuan Thai ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Angiogenic Factor ◽  
Tubule Formation ◽  
Nitric Oxide Synthase Inhibitor ◽  
Therapeutic Implications ◽  
Synthase Inhibitor ◽  
Oxide Synthase ◽  
First Time

Background: Angiogenesis and neovascularization are essential processes that follow ischemia insults. Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) not only induces endothelial cell (EC) death and inhibits angiogenesis, but also promotes EC migration, invasion and proliferation in vitro . These seemingly opposite effects make its role in angiogenesis in vivo unclear. Using TRAIL -/- and wild-type mice, we sought to determine the role of TRAIL in angiogenesis and neovascularisation. We also sought mechanisms in vitro . Methods and Results: Reduced vascularisation assessed by real-time in vivo 3D Vevo ultrasound imaging and CD31 staining was observed in TRAIL -/- mice 28 d after hindlimb ischemia. Moreover, reduced capillary formation and increased apoptosis was evident in TRAIL -/- muscles even at 3 d after ischemic surgery. We have previously shown that fibroblast growth factor-2 (FGF-2), a potent angiogenic factor, regulates TRAIL gene expression in vascular smooth muscle cells. Indeed, FGF-2 also regulates TRAIL expression in ECs, and FGF-2-inducible proliferation, migration and tubule formation was inhibited with siRNA targeting TRAIL. Notably, both FGF-2 and TRAIL significantly increased NOX4 expression. TRAIL-inducible angiogenic activity in ECs was inhibited with siRNAs targeting NOX4, and consistent with these, NOX4 mRNA was reduced in 3 d ischemic hindlimbs of TRAIL -/- mice. TRAIL stimulated intracellular H 2 O 2 levels in ECs, and TRAIL-inducible proliferation, migration and tubule formation was inhibited with not only PEG-catalase, a H 2 O 2 scavenger, but also blocked with L-NAME, a nitric oxide synthase inhibitor. Conclusions: This is the first demonstration showing that TRAIL promotes angiogenesis in vivo . We show for the first time that the TRAIL stimulates NOX4 expression to mediate nitric oxide-dependent angiogenic effects. This has significant therapeutic implications such that TRAIL may improve the angiogenic response to ischemia and increase perfusion recovery in patients with CVD and diabetes.

Abstract P283: Parkin Mediates Mitophagy in Cardioprotection

2011 ◽  
Vol 109 (suppl_1) ◽  
Author(s):  
Allen M Andres ◽  
Chengqun Huang ◽  
Eric P Ratliff ◽  
Genaro Hernandez ◽  
Pamela Lee ◽  
...  
Keyword(s):  
Ex Vivo ◽  
Wild Type ◽  
Simulated Ischemia ◽  
Selective Targeting ◽  
Cardioprotective Effects ◽  
Mitochondrial Turnover ◽  
First Time

Autophagy-dependent mitochondrial turnover in response to cellular stress is necessary for maintaining cellular homeostasis. However, the mechanisms that govern the selective targeting of damaged mitochondria are poorly understood. Parkin, an E3 ubiquitin ligase, has been shown to be essential for the selective clearance of damaged mitochondria. Parkin is expressed in the heart, yet its function has not been investigated in the context of cardioprotection. We previously reported that autophagy is required for cardioprotection by ischemic preconditioning (IPC). In the present study, we used simulated ischemia in vitro and IPC in hearts (in vivo and ex vivo) to investigate the role of Parkin in mediating cardioprotection. In HL-1 cells, simulated ischemia induced Parkin translocation to mitochondria and mitochondrial elimination. Mitochondrial loss was blunted in Atg5-deficient cells, revealing the requirement for autophagy in mitochondrial elimination. Consistent with previous reports implicating p62/SQSTM1 in mitophagy, we found that downregulation of p62 attenuated mitophagy and exacerbated cell death in HL-1 cardiomyocytes subjected to simulated ischemia. While wild type mice showed p62 translocation to mitochondria after IPC, Parkin knockout mice exhibited attenuated translocation of p62 to mitochondria. Importantly, ablation of Parkin in mice abolished the cardioprotective effects of IPC. These results reveal for the first time the crucial role of Parkin and mitophagy in cardioprotection.

scholarly journals Candida albicans forms biofilms on the vaginal mucosa

Microbiology ◽  
2010 ◽  
Vol 156 (12) ◽  
pp. 3635-3644 ◽  
Author(s):  
M. M. Harriott ◽  
E. A. Lilly ◽  
T. E. Rodriguez ◽  
P. L. Fidel ◽  
M. C. Noverr
Keyword(s):  
Biofilm Formation ◽  
Ex Vivo ◽  
Microscopic Analysis ◽  
Vaginal Mucosa ◽  
First Time ◽  
Established Role ◽  
Type Strains

Current understanding of resistance and susceptibility to vulvovaginal candidiasis challenges existing paradigms of host defence against fungal infection. While abiotic biofilm formation has a clearly established role during systemic Candida infections, it is not known whether C. albicans forms biofilms on the vaginal mucosa and the possible role of biofilms in disease. In vivo and ex vivo murine vaginitis models were employed to examine biofilm formation by scanning electron and confocal microscopy. C. albicans strains included 3153A (lab strain), DAY185 (parental control strain), and mutants defective in morphogenesis and/or biofilm formation in vitro (efg1/efg1 and bcr1/bcr1). Both 3153A and DAY815 formed biofilms on the vaginal mucosa in vivo and ex vivo as indicated by high fungal burden and microscopic analysis demonstrating typical biofilm architecture and presence of extracellular matrix (ECM) co-localized with the presence of fungi. In contrast, efg1/efg1 and bcr1/bcr1 mutant strains exhibited weak or no biofilm formation/ECM production in both models compared to wild-type strains and complemented mutants despite comparable colonization levels. These data show for the first time that C. albicans forms biofilms in vivo on vaginal epithelium, and that in vivo biotic biofilm formation requires regulators of biofilm formation (BCR1) and morphogenesis (EFG1).

Role of inducible nitric oxide synthase in the regulation of leucocyte recruitment

2000 ◽  
Vol 100 (1) ◽  
pp. 1-12 ◽  
Author(s):  
Michael J. HICKEY
Keyword(s):  
Nitric Oxide ◽  
Endothelial Cells ◽  
Nitric Oxide Synthase ◽  
Cell Types ◽  
Adhesive Interactions ◽  
Oxide Synthase ◽  
Leucocyte Recruitment

Constitutively produced nitric oxide released by endothelial cells has been shown to act as an endogenous agent which inhibits the rolling and adhesion of leucocytes in the microcirculation. However, during various types of inflammation, expression of the inducible form of nitric oxide synthase (iNOS) can dramatically increase the amount of nitric oxide present in tissues. Furthermore, as iNOS can be expressed by a wide variety of cell types, the distribution of nitric oxide is likely to be altered relative to that in unstimulated tissue. Under these conditions, it is less well understood whether iNOS-derived nitric oxide retains the anti-adhesive capabilities of constitutively produced nitric oxide. This review summarizes work done to examine this issue. Three main approaches have been used. In vitro studies have examined the role of iNOS in adhesive interactions between stimulated endothelial cells and leucocytes, providing evidence of an anti-adhesive effect of iNOS. In addition, the role of iNOS has been examined in vivo in animal models of inflammation using pharmacological iNOS inhibitors. These experiments were extended by the advent of the iNOS-deficient (iNOS-/-) mouse. Intravital microscopy studies of these mice have indicated that, under conditions of low-dose endotoxaemia, iNOS-derived nitric oxide can inhibit leucocyte rolling and adhesion. The potential mechanisms for these effects are discussed. In contrast, several other studies have observed either no effect or an enhancing effect of iNOS on inflammatory leucocyte recruitment. Taken together, these studies suggest that the importance of iNOS in modulating leucocyte recruitment can vary according to the type of inflammatory response.

scholarly journals Islet constitutive nitric oxide synthase and glucose regulation of insulin release in mice

1999 ◽  
Vol 163 (1) ◽  
pp. 39-48 ◽  
Author(s):  
B Akesson ◽  
R Henningsson ◽  
A Salehi ◽  
I Lundquist
Keyword(s):  
Nitric Oxide ◽  
Nitric Oxide Synthase ◽  
Insulin Release ◽  
Ex Vivo ◽  
Insulin Response ◽  
Glucose Regulation ◽  
Nos Inhibitor ◽  
Oxide Synthase

We have studied, by a combined in vitro and in vivo approach, the relation between the inhibitory action of N(G)-nitro-l-arginine methyl ester (L-NAME), a selective inhibitor of nitric oxide synthase (NOS), on the activity of islet constitutive NOS (cNOS) and glucose regulation of islet hormone release in mice. The cNOS activity in islets incubated in vitro at 20 mM glucose was not appreciably affected by 0.05 or 0.5 mM L-NAME, but was greatly suppressed (-60%) by 5 mM L-NAME. Similarly, glucose-stimulated insulin release was unaffected by the lower concentrations of L-NAME but greatly enhanced in the presence of 5 mM of the NOS inhibitor. In incubated islets inhibition of cNOS activity resulted in a modestly enhanced insulin release in the absence of glucose, did not display any effect at physiological or subphysiological glucose concentrations, but resulted in a markedly potentiated insulin release at hyperglycaemic glucose concentrations. In the absence of glucose, glucagon secretion was suppressed by L-NAME. The dynamics of glucose-induced insulin release and (45)Ca(2+) efflux from perifused islets revealed that L-NAME caused an immediate potentiation of insulin release, and a slight increase in (45)Ca(2+) efflux. In islets depolarized with 30 mM K(+) in the presence of the K(+)(ATP) channel opener, diazoxide, L-NAME still greatly potentiated glucose-induced insulin release. Finally, an i.v. injection of glucose to mice pretreated with L-NAME was followed by a markedly potentiated insulin response, and an improved glucose tolerance. In accordance, islets isolated directly ex vivo after L-NAME injection displayed a markedly reduced cNOS activity. In conclusion, we have shown here, for the first time, that biochemically verified suppression of islet cNOS activity, induced by the NOS inhibitor L-NAME, is accompanied by a marked potentiation of glucose-stimulated insulin release both in vitro and in vivo. The major action of NO to inhibit glucose-induced insulin release is probably not primarily linked to changes in Ca(2+) fluxes and is exerted mainly independently of membrane depolarization events.

scholarly journals Role of nitric oxide synthase on brain GABA transaminase activity and GABA levels

2018 ◽  
Vol 68 (3) ◽  
pp. 349-359 ◽  
Author(s):  
Lourdes A. Vega Rasgado ◽  
Guillermo Ceballos Reyes ◽  
Fernando Vega Díaz
Keyword(s):  
Nitric Oxide ◽  
Ex Vivo ◽  
Transaminase Activity ◽  
Gaba Transaminase ◽  
Neuronal Nos ◽  
New Generation ◽  
Oxide Synthase ◽  
Brain Gaba

Abstract In an attempt to clarify the controversial role of nitric oxide (NO) in seizures, the effects of NO on brain GABA transaminase (GABA-T) activity and GABA levels were investigated. To this aim, the effects of the substrate (l-arginine) and inhibitors (Nω-nitro-l-arginine methyl ester, 7-nitroindazole) of NO synthase (NOS) on GABA-T activity and GABA levels in vitro and ex vivo were analyzed. In vitro NO diminished GABA-T activity and increased GABA. Ex vivo NO modified GABA-T activity and GABA levels biphasically. Inhibition of endothelial and neuronal NOS (eNOS and nNOS) had opposite effects on GABA-T activity and GABA levels, even during seizures induced by pentylenetetrazole. Different effects of NO on GABA-T activity and on GABA levels, depending on the NOS isoform involved, may explain its contradictory role in seizures, the endothelial NOS acting as an anticonvulsant and the neuronal NOS as a proconvulsant. nNOS inhibitors may represent a new generation of antiepileptics.

scholarly journals Protection against Doxorubicin-Induced Cardiotoxicity through Modulating iNOS/ARG 2 Balance by Electroacupuncture at PC6

2021 ◽  
Vol 2021 ◽  
pp. 1-17
Author(s):  
Jingya Wang ◽  
Lin Yao ◽  
Xiaoli Wu ◽  
Qi Guo ◽  
Shengxuan Sun ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Protective Effect ◽  
No Production ◽  
Myocardial Cells ◽  
Molecular Biotechnology ◽  
Underlying Mechanisms ◽  
Vitro Analysis ◽  
Oxide Synthase

Background. Doxorubicin (DOX) is a commonly used chemotherapeutic drug but is limited in clinical applications by its cardiotoxicity. Neiguan acupoint (PC6) is a well-recognized acupoint for the treatment of cardiothoracic disease. However, whether acupuncture at PC6 could be effective in preventing DOX-induced cardiotoxicity is still unknown. Methods. A set of experiments were performed with myocardial cells, wild type, inducible nitric oxide synthase knockout (iNOS-/-), and myocardial-specific ablation arginase 2 (Myh6-ARG 2-/-) mice. We investigated the protective effect and the underlying mechanisms for electroacupuncture (EA) against DOX-induced cardiotoxicity by echocardiography, immunostaining, biochemical analysis, and molecular biotechnology in vivo and in vitro analysis. Results. We found that DOX-mediated nitric oxide (NO) production was positively correlated with the iNOS level but has a negative correlation with the arginase 2 (ARG 2) level in both myocardial cells and tissues. Meanwhile, EA at PC6 alleviated cardiac dysfunction and cardiac hypertrophy in DOX-treated mice. EA at PC6 blocked the upregulation of NO production in accompanied with the downregulated iNOS and upregulated ARG 2 levels in myocardial tissue induced by DOX. Furthermore, knockout iNOS prevented cardiotoxicity and EA treatment did not cause the further improvement of cardiac function in iNOS-/- mice treated by DOX. In contrast, deficiency of myocardial ARG 2 aggravated DOX-induced cardiotoxicity and reduced EA protective effect. Conclusion. These results suggest that EA treatment at PC6 can prevent DOX-induced cardiotoxicity through modulating NO production by modulating the iNOS/ARG 2 balance in myocardial cells.

The Role of Polyphenols in the Modulation of Plasma Non-Enzymatic Antioxidant Capacity (NEAC)

2012 ◽  
Vol 82 (3) ◽  
pp. 228-232 ◽  
Author(s):  
Mauro Serafini ◽  
Giuseppa Morabito
Keyword(s):  
Antioxidant Capacity ◽  
Dietary Intervention ◽  
Ex Vivo ◽  
The Body ◽  
Dietary Polyphenols ◽  
Enzymatic Antioxidant ◽  
Endogenous Antioxidant

Dietary polyphenols have been shown to scavenge free radicals, modulating cellular redox transcription factors in different in vitro and ex vivo models. Dietary intervention studies have shown that consumption of plant foods modulates plasma Non-Enzymatic Antioxidant Capacity (NEAC), a biomarker of the endogenous antioxidant network, in human subjects. However, the identification of the molecules responsible for this effect are yet to be obtained and evidences of an antioxidant in vivo action of polyphenols are conflicting. There is a clear discrepancy between polyphenols (PP) concentration in body fluids and the extent of increase of plasma NEAC. The low degree of absorption and the extensive metabolism of PP within the body have raised questions about their contribution to the endogenous antioxidant network. This work will discuss the role of polyphenols from galenic preparation, food extracts, and selected dietary sources as modulators of plasma NEAC in humans.

Vasculoprotective Role of Inducible Nitric Oxide Synthase at Inflammatory Coronary Lesions Induced by Chronic Treatment With Interleukin-1β in Pigs in Vivo

Circulation ◽  
1997 ◽  
Vol 96 (9) ◽  
pp. 3104-3111 ◽  
Author(s):  
Yoshihiro Fukumoto ◽  
Hiroaki Shimokawa ◽  
Toshiyuki Kozai ◽  
Toshiaki Kadokami ◽  
Kouichi Kuwata ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Nitric Oxide Synthase ◽  
Inducible Nitric Oxide Synthase ◽  
Chronic Treatment ◽  
Interleukin 1Β ◽  
Coronary Lesions ◽  
Oxide Synthase ◽  
Inducible Nitric Oxide

scholarly journals Cathepsin L plays a key role in SARS-CoV-2 infection in humans and humanized mice and is a promising target for new drug development

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Miao-Miao Zhao ◽  
Wei-Li Yang ◽  
Fang-Yuan Yang ◽  
Li Zhang ◽  
Wei-Jin Huang ◽  
...  
Keyword(s):  
Drug Development ◽  
Cathepsin L ◽  
Human Cells ◽  
New Drugs ◽  
Disease Course ◽  
Promising Target ◽  
First Time

AbstractTo discover new drugs to combat COVID-19, an understanding of the molecular basis of SARS-CoV-2 infection is urgently needed. Here, for the first time, we report the crucial role of cathepsin L (CTSL) in patients with COVID-19. The circulating level of CTSL was elevated after SARS-CoV-2 infection and was positively correlated with disease course and severity. Correspondingly, SARS-CoV-2 pseudovirus infection increased CTSL expression in human cells in vitro and human ACE2 transgenic mice in vivo, while CTSL overexpression, in turn, enhanced pseudovirus infection in human cells. CTSL functionally cleaved the SARS-CoV-2 spike protein and enhanced virus entry, as evidenced by CTSL overexpression and knockdown in vitro and application of CTSL inhibitor drugs in vivo. Furthermore, amantadine, a licensed anti-influenza drug, significantly inhibited CTSL activity after SARS-CoV-2 pseudovirus infection and prevented infection both in vitro and in vivo. Therefore, CTSL is a promising target for new anti-COVID-19 drug development.

Sign in / Sign up

Export Citation Format

Share Document