Nitric oxide signalling in plant interactions with pathogenic fungi and oomycetes

Author(s):  
Tereza Jedelská ◽  
Lenka Luhová ◽  
Marek Petřivalský

Abstract Nitric oxide (NO) and reactive nitrogen species have emerged as crucial signalling and regulatory molecules across all organisms. In plants, fungi and fungi-like oomycetes, NO is involved in the regulation of multiple processes during their growth, development, reproduction, responses to the external environment and biotic interactions. It has become evident that NO is produced and used as signalling and defence cues by both partners in multiple forms of plant interactions with their microbial counterparts, ranging from symbiotic to pathogenic modes. This review summarizes current knowledge on NO role in plant-pathogen interactions, focused on biotrophic, necrotrophic and hemibiotrophic fungi and oomycetes. Actual advances and gaps in the identification of NO sources and fate in plant and pathogen cells are discussed. We review the decisive role of time- and site-specific NO production in germination, oriented growth and active penetration of filamentous pathogens to the host tissues, as well in pathogen recognition, and defence activation in plants. Distinct functions of NO are highlighted on diverse interactions of host plants with fungal and oomycete pathogens of different lifestyles, where NO in interplay with reactive oxygen species govern successful plant colonization, cell death and resistance establishment.

2019 ◽  
Vol 20 (7) ◽  
pp. 1755 ◽  
Author(s):  
Kaiwen Mu ◽  
Shengwu Yu ◽  
David D. Kitts

Important functions of intestinal epithelial cells (IECs) include enabling nutrient absorption to occur passively and acting as a defense barrier against potential xenobiotic components and pathogens. A compromise to IEC function can result in the translocation of bacteria, toxins, and allergens that lead to the onset of disease. Thus, the maintenance and optimal function of IECs are critically important to ensure health. Endogenous biosynthesis of nitric oxide (NO) regulates IEC functionality both directly, through free radical activity, and indirectly through cell signaling mechanisms that impact tight junction protein expression. In this paper, we review the current knowledge on factors that regulate inducible nitric oxide synthase (iNOS) and the subsequent roles that NO has on maintaining IECs’ intestinal epithelial barrier structure, functions, and associated mechanisms of action. We also summarize important findings on the effects of bioactive dietary food components that interact with NO production and affect downstream intestinal epithelium integrity.


2006 ◽  
Vol 19 (9) ◽  
pp. 970-975 ◽  
Author(s):  
Emmanuel Baudouin ◽  
Laurent Pieuchot ◽  
Gilbert Engler ◽  
Nicolas Pauly ◽  
Alain Puppo

Nitric oxide (NO) has recently gained interest as a major signaling molecule during plant development and response to environmental cues. Its role is particularly crucial for plant-pathogen interactions, during which it participates in the control of plant defense response and resistance. Indication for the presence of NO during symbiotic interactions has also been reported. Here, we defined when and where NO is produced during Medicago truncatula-Sinorhizobium meliloti symbiosis. Using the NO-specific fluorescent probe 4,5-diaminofluorescein diacetate, NO production was detected by confocal microscopy in functional nodules. NO production was localized in the bacteroid-containing cells of the nodule fixation zone. The infection of Medicago roots with bacterial strains impaired in nitrogenase or nitrite reductase activities lead to the formation of nodules with an unaffected NO level, indicating that neither nitrogen fixation nor denitrification pathways are required for NO production. On the other hand, the NO synthase inhibitor N-methyl-L-arginine impaired NO detection, suggesting that a NO synthase may participate to NO production in nodules. These data indicate that a NO production occurs in functional nodules. The location of such a production in fully metabolically active cells raises the hypothesis of a new function for NO during this interaction unrelated to defense and cell-death activation.


2018 ◽  
Vol 16 (2) ◽  
pp. 194-199
Author(s):  
Wioletta Ratajczak-Wrona ◽  
Ewa Jablonska

Background: Polymorphonuclear neutrophils (PMNs) play a crucial role in the innate immune system’s response to microbial pathogens through the release of reactive nitrogen species, including Nitric Oxide (NO). </P><P> Methods: In neutrophils, NO is produced by the inducible Nitric Oxide Synthase (iNOS), which is regulated by various signaling pathways and transcription factors. N-nitrosodimethylamine (NDMA), a potential human carcinogen, affects immune cells. NDMA plays a major part in the growing incidence of cancers. Thanks to the increasing knowledge on the toxicological role of NDMA, the environmental factors that condition the exposure to this compound, especially its precursors- nitrates arouse wide concern. Results: In this article, we present a detailed summary of the molecular mechanisms of NDMA’s effect on the iNOS-dependent NO production in human neutrophils. Conclusion: This research contributes to a more complete understanding of the mechanisms that explain the changes that occur during nonspecific cellular responses to NDMA toxicity.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Haidy A. Saleh ◽  
Eman Ramdan ◽  
Mohey M. Elmazar ◽  
Hassan M. E. Azzazy ◽  
Anwar Abdelnaser

AbstractDoxorubicin (DOX) chemotherapy is associated with the release of inflammatory cytokines from macrophages. This has been suggested to be, in part, due to DOX-mediated leakage of endotoxins from gut microflora, which activate Toll-like receptor 4 (TLR4) signaling in macrophages, causing severe inflammation. However, the direct function of DOX on macrophages is still unknown. In the present study, we tested the hypothesis that DOX alone is incapable of stimulating inflammatory response in macrophages. Then, we compared the anti-inflammatory effects of curcumin (CUR), resveratrol (RES) and sulforaphane (SFN) against lipopolysaccharide/interferon-gamma (LPS/IFN-γ)-mediated inflammation in the absence or presence of DOX. For this purpose, RAW 264.7 cells were stimulated with LPS/IFN-γ (10 ng/mL/10 U/mL) in the absence or presence of DOX (0.1 µM). Our results showed that DOX alone is incapable of stimulating an inflammatory response in RAW 264.7 macrophages. Furthermore, after 24 h of incubation with LPS/IFN-γ, a significant increase in tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), and inducible nitric oxide synthase (iNOS) mRNA levels was observed. Similarly, nitric oxide (NO) production and TNF-α and IL-6 protein levels were significantly upregulated. Moreover, in LPS/IFN-γ-treated macrophages, the microRNAs (miRNAs) miR-146a, miR-155, and miR-21 were significantly overexpressed. Interestingly, upon testing CUR, RES, and SFN against LPS/IFN-γ-mediated inflammation, only SFN was able to significantly reverse the LPS/IFN-γ-mediated induction of iNOS, TNF-α and IL-6 and attenuate miR-146a and miR-155 levels. In conclusion, SFN, at the transcriptional and posttranscriptional levels, exhibits potent immunomodulatory action against LPS/IFN-γ-stimulated macrophages, which may indicate SFN as a potential treatment for DOX-associated inflammation.


Marine Drugs ◽  
2021 ◽  
Vol 19 (2) ◽  
pp. 65
Author(s):  
Byeoung-Kyu Choi ◽  
Duk-Yeon Cho ◽  
Dong-Kug Choi ◽  
Phan Thi Hoai Trinh ◽  
Hee Jae Shin

Two new phomaligols, deketo-phomaligol A (1) and phomaligol E (2), together with six known compounds (3–8) were isolated from the culture broth of the marine-derived fungus Aspergillus flocculosus. Compound 1 was first isolated as a phomaligol derivative possessing a five-membered ring. The structures and absolute configurations of the new phomaligols were determined by detailed analyses of mass spectrometry (MS), nuclear magnetic resonance (NMR) data, optical rotation values and electronic circular dichroism (ECD). In addition, the absolute configurations of the known compounds 3 and 4 were confirmed by chemical oxidation and comparison of optical rotation values. Isolated compounds at a concentration of 100 μM were screened for inhibition of nitric oxide (NO) production in lipopolysaccharide (LPS)-induced BV-2 microglial cells. Among the compounds, 4 showed moderate anti-neuroinflammatory effects with an IC50 value of 56.6 μM by suppressing the production of pro-inflammatory mediators in activated microglial cells without cytotoxicity.


2021 ◽  
pp. 1-23
Author(s):  
Kosar Valaei ◽  
Javad Mehrabani ◽  
Alexei Wong

Abstract L-citrulline (L-Cit) is a nonessential amino acid that stimulates nitric oxide (NO) production and improves exercise performance by reducing muscle damage indices; however, the direct benefits of L-Cit on antioxidant markers are unclear. The aim of this study was to examine antioxidant responses to high-intensity interval exercise following acute L-Cit supplementation. Nine young men (21 ± 1 years) participated in a double-blind crossover study in which they received 12 g of L-Cit and placebo (PL) an hour prior to high-intensity interval exercise on two occasions, separated by a seven-day washout period. Blood samples were obtained before (PRE), immediately after (IP), 10 (10P), and 30 min after exercise (30P) from the cubital vein using standard procedures. Serum concentrations of superoxide dismutase (SOD), glutathione peroxidase (GPx), catalase (CAT), and NO metabolites (NOx) were measured. The exercise protocol significantly elevated SOD (p = 0.01) and GPx (p = 0.048) from PRE to 10P in the L-Cit group with greater changes than the PL group. CAT concentrations increased IP (p = 0.014) and remained elevated at 10P (p = 0.03) and 30P (p = 0.015) in both the L-Cit and PL conditions. NOx concentrations increased IP (p = 0.05) in the L-Cit group with greater changes than PL group in PRE to IP, PRE to 10P, and PRE to 30P (p < 0.05). Our data indicate that L-Cit supplementation (single 12 g dose pre-exercise) induces improvements in antioxidant markers following a session of high-intensity interval exercise in young men.


Author(s):  
Mohamed A. Salama ◽  
Mohamed A. Younis ◽  
Roba M. Talaat

AbstractObjectiveThe present study aimed to evaluate cytotoxic, apoptotic, and anti-inflammatory properties of bee venom (BV) as well as changes in cytokine secretion levels and nitric oxide (NO) production using three different cancer cell lines [liver (Hep-G2), breast (MCF-7), and cervical (HPV-18 infected HeLa cells)] and two normal cells (splenocytes and macrophages (MQ).MethodsCytotoxic activity of BV against tumor cell lines and normal splenocytes/MQ was tested by MTT assay. By ELISA (ELISA); Tumor necrosis factor (TNF-α), Interleukine (IL-10) and interferon (IFN-γ) were measured. Caspase three expressions was evaluated using reverse transcription-polymerase chain reaction (RT-PCR). Nitric oxide (NO) was estimated using a colorimetric assay.ResultsBV has a significant cytotoxic effect on all cell lines in a dose- and time-dependent manner; none of them was toxic for normal cells. Treating Hep-G2 cells with BV showed a reduction in IL-10, elevation in TNF-α with no change in IFN-γ level. MCF-7 cells have low IL-10 and TNF-α and high IFN-γ production level. Elevation of IL-10 and IFN-γ coincides with a reduction in TNF-α level was demonstrated in HeLa cells. The expression of Caspase three was dramatically increased with elevation in BV concentration in all tested cancer cell lines. A gradual decrease in NO production by MQ with increasing BV dose was observed.ConclusionTaken together, our results stressed on the importance of BV as a potent anti-tumor agent against various types of cancers (Liver, Breast, and Cervix). Further steps towards the use of BV for pharmacological purposes must be done.


Author(s):  
Hadis Shakeri ◽  
Jente R.A. Boen ◽  
Sofie De Moudt ◽  
Jhana O. Hendrickx ◽  
Arthur J.A. Leloup ◽  
...  

Endothelial cells (ECs) secrete different paracrine signals that modulate the function of adjacent cells; two examples of these paracrine signals are nitric oxide (NO) and neuregulin-1 (NRG1), a cardioprotective growth factor. Currently, it is undetermined whether one paracrine factor can compensate for the loss of another. Herein, we hypothesized that NRG1 can compensate for endothelial NO synthase (eNOS) deficiency. Methods. We characterized eNOS null and wild type (WT) mice by cardiac ultrasound and histology and we determined circulating NRG1 levels. In a separate experiment, 8 groups of mice were divided into 4 groups of eNOS null mice and wild type (WT) mice; half of the mice received angiotensin II (Ang II) to induce a more severe phenotype. Mice were randomized to daily injections with NRG1 or vehicle for 28 days. Results. eNOS deficiency increased NRG1 plasma levels, indicating that ECs increase their NRG1 expression when NO production is deleted. eNOS deficiency also increased blood pressure, lowered heart rate, induced cardiac fibrosis, and affected diastolic function. In eNOS null mice, Ang II administration increased cardiac fibrosis, but also induced cardiac hypertrophy and renal fibrosis. NRG1 administration prevented the cardiac and renal hypertrophy and fibrosis caused by Ang II infusion and eNOS deficiency. Moreover, Nrg1 expression in the myocardium is shown to be regulated by miR-134. Conclusion. This study indicates that administration of endothelium-derived NRG1 can compensate for eNOS deficiency in the heart and kidneys.


1997 ◽  
Vol 273 (3) ◽  
pp. L504-L512 ◽  
Author(s):  
Y. C. Huang ◽  
P. W. Fisher ◽  
E. Nozik-Grayck ◽  
C. A. Piantadosi

Because both the biosynthesis of nitric oxide (NO.) and its metabolic fate are related to molecular O2, we hypothesized that hypoxia would alter the effects of NO. during ischemia-reperfusion (IR) in the lung. In this study, buffer-perfused lungs from rabbits underwent either normoxic IR (AI), in which lungs were ventilated with 21% O2 during ischemia and reperfusion, or hypoxic IR (NI), in which lungs were ventilated with 95% N2 during ischemia followed by reoxygenation with 21% O2. Lung weight gain (WG) and pulmonary artery pressure (Ppa) were monitored continuously, and microvascular pressure (Pmv) was measured after reperfusion to calculate pulmonary vascular resistance. We found that both AI and NI produced acute lung injury, as shown by increased WG and Ppa during reperfusion. In AI, where perfusate PO2 was > 100 mmHg, the administration of the NO. synthase inhibitor N-nitro-L-arginine methyl ester (L-NAME) before ischemia worsened WG and Ppa. Pmv also increased, suggesting a hydrostatic mechanism involved in edema formation. The effects of L-NAME could be attenuated by giving L-arginine and exogenous NO. donors before ischemia or before reperfusion. Partial protection was also provided by superoxide dismutase. In contrast, lung injury in NI at perfusate PO2 of 25-30 mmHg was attenuated by L-NAME; this effect could be reversed by L-arginine. Exogenous NO. donors given either before ischemia or before reperfusion, however, did not increase lung injury. NO. production was measured by quantifying the total nitrogen oxides (NOx) accumulating in the perfusate. The average rate of NOx accumulation was greater in AI than in NI. We conclude that hypoxia prevented the protective effects of NO on AI lung injury. The effects of hypoxia may be related to lower NO. production relative to oxidant stress during IR and/or altered metabolic fates of NO.-mediated production of peroxynitrite by hypoxic ischemia.


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