Nitric Oxide In Regulation Research Articles

Stimulating action of sodium nitroprusside and vinasse on salicin and direct regeneration in Salix Safsaf Forssk.

The present study aimed to enhance salicin and direct regeneration inwillow (Salix safsaf Forssk) using the sodium nitroprusside (SNP) regulation of nitric oxide (NO) and vinasse for its nutrition effect in culture medium. Internodes of Salix safsaf were cultured on Murashige and Skoog (MS) medium supplemented with benzyl adenine (BA) (0.25 mg L-1) and different concentrations of SNP (0, 5, 10, 15, and 20 mg L-1) or vinasse (0, 5, 10, and 20%) to examine shoot regeneration, antioxidant defense enzyme activity, total phenolic compounds, flavonoids, and salicine contents. The reported data revealed that application of SNP at15 mg L-1 and vinasse at10% induced asignificant effectin vitro Salix safsaf shoot regeneration. To confirm that, nitric oxide is required for auxin-mediated activation of cell division in a dose-dependent manner. A concentration of 15 mg L-1 SNP promotes regeneration and salicin accumulation (3162.16mg/100g) during signaling action. On the other hand, the cross talk effect of nitric oxide and vinasse combination inSalix safsaf significantly induced a synergistic effect on direct propagation more than vinasse alone. SNP significantly stimulates salicylate accumulation in a dose-dependent manner, but the data on the association of vinasse and SNP on salicylate up-regulation showed a significant reduction in salicin accumulation when SNP was combined with 10% vinasse, which directly affected the signaling action of SNP as secondary product stimulators. Vinasse's phenolic compounds affect directly on thereduction activity ofSNP to suppress its signaling action, or indirectly by inhibiting the sequence cascade of the SNP signaling transduction process to decrease the accumulation of salicin contents. Data confirmed that vinasse andSNP stimulatedtheantioxidant enzymes activity throw quenching thestimulated reactive oxygen species that produced via SNP. Results show that modified media with SNP administration at 15 mg L-1 and the combination of vinasse at 10% and SNP at 15 mg L-1 are recommended for modifying tissue culture media for induced direct regeneration and salicin accumulation in tissue culture applications, which will be very useful for commercial salicin overproduction as a biological active ingredient in willows.

Regulation and microbial response mechanism of nitric oxide to copper-containing swine wastewater treated by Pistia stratiotes

As a signaling molecule, Nitric oxide (NO) has been widely used in abiotic stress mitigation studies.Pistia stratiotes showed a good synergistic removal effect on heavy metals, nitrogen and phosphorus, but the high concentration of copper(Cu) in swine wastewater inhibited the comprehensive removal ability of Pistia stratiotes. At present, it is not clear how the addition of NO regulates the stress resistance mechanism of Pistia stratiotes to copper in swine wastewater, and the microbial response mechanism accompanying this process is not yet clear. Therefore, in the concentration range of 0.31∼4 mg·L−1Cu2+ and NO concentration of 0,0.05 and 0.1 mg L−1, the removal effect of Pistia stratiotes on copper from swine wastewater was studied. The results showed as follows: The treatment of non-available copper in groups M and H increased by 10.67% and 22.31%, respectively, compared with that in group L. The critical point of inhibiting effect of NO on growth rate was 2.03 mg·L−1Cu. By measuring three-dimensional fluorescence spectrum, combined with parallel factor analysis and principal component analysis, it was confirmed that exogenous addition of NO affected the humification degree of dissolved organic matter(DOM) and promoted the chelation of organic matter with copper. With the increase of Cu concentration, the Reyranella and Prosthecobacter with certain copper resistance gradually gained advantages. Redundancy analysis(RDA) showed that Emiticicia had a strong correlation with the removal rates of ammonia nitrogen, total phosphorus and copper in swine wastewater, while hgcI_clade had a strong correlation with the removal rates of total nitrogen. In conclusion, controlling the dosage of NO can effectively improve the tolerance and removal effect of Pistia stratiotes on copper in swine wastewater, which is of great significance for promoting the treatment and resource transformation of swine wastewater.

Impact of different hormones on the regulation of nitric oxide in diabetes

Polymetabolic syndrome achieved pandemic proportions and dramatically influenced public health systems functioning worldwide. Chronic vascular complications are the major contributors to increased morbidity, disability, and mortality rates in diabetes patients. Nitric oxide (NO) is among the most important vascular bed function regulators. However, NO homeostasis is significantly deranged in pathological conditions. Additionally, different hormones directly or indirectly affect NO production and activity and subsequently act on vascular physiology. In this paper, we summarize the recent literature data related to the effects of insulin, estradiol, insulin-like growth factor-1, ghrelin, angiotensin II and irisin on the NO regulation in physiological and diabetes circumstances.

(046) THE ROLE OF ADENOSINE IN THE RELAXANT MECHANISM OF RAT DISTAL VAGINA

Abstract Introduction Adenosine (ADO) is a purinergic neuromodulator that in the male exerts a positive effect on penile erection by controlling smooth muscle (SM) relaxation. However, its role in the relaxant/contractile pathways in the vagina is yet to be investigated. Objective The aim of this study was to characterize the effect of ADO stimulation on SM activity in distal vagina, evaluating its possible effect on the regulation of nitric oxide (NO) pathway using a validated animal model of female Sprague-Dawley rats. Methods The immunolocalization of ADORA2A and ADORA2B in distal vagina tissues was detected by immunohistological staining. In vitro contractility studies on noradrenaline (NA)-precontracted vaginal strips from intact Sprague-Dawley rats were performed; rat smooth muscle cells (rvSMCs) from distal vagina of intact animals were stimulated with ADO for cyclic adenosine monophosphate (cAMP) quantification. mRNA (messenger ribonucleic acid) isolated from vaginal tissue was analyzed by semi-quantitative Reverse Transcriptase-Polymerase Chain Reaction. Results All ADORAs mRNA were expressed in the vaginal tissue, with a significant prevalence of ADORA2B; furthermore, ADORA2A and ADORA2B immunolocalization highlighted that both receptors are highly expressed in the epithelium, in blood capillaries of the vascular bed and in the smooth muscle bundles of vagina wall. In vitro ADO stimulation induced a dose-dependent relaxation (IC50=31.9±2.38 μM), which was significantly reduced by the administration of NO-synthase inhibitor L-NAME; similar effects were observed after the mechanical ablation of endothelium and in vitro administration of the soluble guanylate cyclase inhibitor ODQ, highlighting the pivotal contribution of NO signaling to the ADO relaxant activity. In vitro stimulation with increasing doses of the selective ADO receptor ADORA2A agonist CGS2-1680 induced a dose-dependent relaxation (IC50=132.6±3.47 nM); a similar but less potent relaxant effect was observed with ADORA2B selective agonist BAY60-6583. The relaxing effect induced by ADO on NA-precontracted vaginal strips was completely counteracted by the stimulation with the re-spectively selective ADORA2A and ADORA2B antagonists SHC-442416 and PSB603; a similar effect was induced by ADORA1 selective antagonist SLV320, but not by ADORA3 selective antagonists VUF5574. The mRNA relative expression of enzymes regulating the ADO turnover [adenosine deami-nase (ADA), 5′-nucleotidase (5NTD), AMP deaminase type 1 and type 2 (AMPD1, AMPD2) and adenosine kinase (ADK)] showed a higher expression of genes regulating the de novo ADO/cAMP syn-thesis (ADK, 5NTD), compared to those acting on ADO degradation (ADA, AMPD1, AMPD2). Finally, stimulation of rvSMCs with increasing doses of ADO induced a significant production of intracellular cAMP after 3 minutes (1 and 10 μM). Conclusions These data show that ADO acts as an important relaxant modulator of the vagina through the activation of its receptors, specifically ADORA2A, and the consequent cAMP-dependent adenylate cyclase re-sponse. However, in vitro studies show that ADO also acts trough the NO-dependent pathway. These results therefore demonstrate for the first time a new relaxant pathway in distal vagina, ADO signaling, that results deeply intertwined with the well-known NO pathway. This finding unravels new biological mechanisms underlying vagina physiology that need to be further studied in future research. Disclosure No.

Nitric Oxide Signaling and Regulation in the Cardiovascular System: Recent Advances.

Nitric oxide (NO) from endothelial NO synthase importantly contributes to vascular homeostasis. Reduced NO production or increased scavenging during disease conditions with oxidative stress contribute to endothelial dysfunction and NO deficiency. In addition to the classical enzymatic NO synthases (NOS) system, NO can also be generated via the nitrate-nitrite-NO pathway. Dietary and pharmacological approaches aimed at increasing NO bioactivity, especially in the cardiovascular system, have been the focus of much research since the discovery of this small gaseous signaling molecule. Despite wide appreciation of the biological role of NOS/NO signaling, questions still remain about the chemical nature of NOS-derived bioactivity. Recent studies show that NO-like bioactivity can be efficiently transduced by mobile NO-ferroheme species, which can transfer between proteins, partition into a hydrophobic phase, and directly activate the soluble guanylyl cyclase-cGMP-protein kinase G pathway without intermediacy of free NO. Moreover, interaction between red blood cells and the endothelium in the regulation of vascular NO homeostasis have gained much attention, especially in conditions with cardiometabolic disease. In this review we discuss both classical and nonclassical pathways for NO generation in the cardiovascular system and how these can be modulated for therapeutic purposes. SIGNIFICANCE STATEMENT: After four decades of intensive research, questions persist about the transduction and control of nitric oxide (NO) synthase bioactivity. Here we discuss NO signaling in cardiovascular health and disease, highlighting new findings, such as the important role of red blood cells in cardiovascular NO homeostasis. Nonclassical signaling modes, like the nitrate-nitrite-NO pathway, and therapeutic opportunities related to the NO system are discussed. Existing and potential pharmacological treatments/strategies, as well as dietary components influencing NO generation and signaling are covered.

A versatile delivery vehicle for cellular oxygen and fuels or metabolic sensor? A review and perspective on the functions of myoglobin.

A canonical view of the primary physiological function of myoglobin (Mb) is that it is an oxygen (O2) storage protein supporting mitochondrial oxidative phosphorylation, especially as the tissue O2 partial pressure (Po2) drops and Mb off-loads O2. Besides O2 storage/transport, recent findings support functions for Mb in lipid trafficking and sequestration, interacting with cellular glycolytic metabolites such as lactate (LAC) and pyruvate (PYR), and "ectopic" expression in some types of cancer cells and in brown adipose tissue (BAT). Data from Mb knockout (Mb-/-) mice and biochemical models suggest additional metabolic roles for Mb, especially regulation of nitric oxide (NO) pools, modulation of BAT bioenergetics, thermogenesis, and lipid storage phenotypes. From these and other findings in the literature over many decades, Mb's function is not confined to delivering O2 in support of oxidative phosphorylation but may serve as an O2 sensor that modulates intracellular Po2- and NO-responsive molecular signaling pathways. This paradigm reflects a fundamental change in how oxidative metabolism and cell regulation are viewed in Mb-expressing cells such as skeletal muscle, heart, brown adipocytes, and select cancer cells. Here, we review historic and emerging views related to the physiological roles for Mb and present working models illustrating the possible importance of interactions between Mb, gases, and small-molecule metabolites in regulation of cell signaling and bioenergetics.

Myoglobin: A versatile age-old oxygen carrying hemoprotein and its emerging role in metabolite regulation in diverse tissues

Myoglobin (Mb) is an age-old heme containing cytoplasmic protein primarily expressed in heart and skeletal muscles, which is capable of rapid release of O2 during the periods of hypoxia or anoxia. The canonical view of the primary physiological function of Mb is that it is a tissue oxygen (O2) storage protein supporting mitochondrial oxidative phosphorylation especially as the tissue O2 partial pressure ( pO2) drops and Mb increasingly offloads O2. For the past 50 years, many investigators are constantly exploring wide-range of physiological functions and metabolic regulation activities of Mb. Advanced genetic engineering tools and molecular techniques revealed important new insights and provided additional functions of Mb. However, accumulating evidence indicates that this paradigm is too narrow, especially in light of recent findings supporting plausible functions for Mb in lipid traffcking and sequestration, binding of small molecules such as lactate (LAC), pyruvate (PYR), glucose (GLU), polyamines, and glutathione (GSH), and “ectopic” expression in some types of cancer cells. Data from Mb knockout mice (Mb−/−) and biochemical models suggest additional metabolic roles for Mb, especially regulation of nitric oxide (NO) pools and modulation of thermogenic brown adipose tissue (BAT) bioenergetics and lipid storage phenotypes. From these and other findings in the literature over many decades, it may be contemplated that the primary role for Mb under most conditions for Mb besides delivering O2 in support of oxidative phosphorylation, but also serve as an O2-sensor that modulates intracellular O2- and NO-responsive molecular signaling pathways. This paradigm shift reflect a fundamental change in how oxidative metabolism and cell regulation are viewed in Mb-expressing cells such as skeletal muscle, heart, brown adipocytes, and select cancer cells. Herein, we present historic and emerging views related to the physiological roles for Mb, and working models illustrating the possible importance of interactions between Mb, gases, and small molecule metabolites in regulation of cell signaling and bioenergetics. USDA-ARS project 6026-51000-010-06S, Sturgis Foundation Grant AWD00054750 and ACRI-ABI Investigator Initiated Grant Award GR037175-4450S ABI. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Identification and Characterization of Potential Anti-Hypertensive Therapeutic Candidates in Rho-related BTB Domain Containing 1 (RhoBTB1)-Cullin 3 (CUL3) Axis

Blood pressure (BP) is regulated by a variety of cellular mechanisms. We previously reported the regulation of endothelial nitric oxide (NO)-dependent vessel tone and BP through RhoBTB1-CUL3 mediated proteasomal turnover of Phosphodiesterase 5 (PDE5). We determined that the C-terminal half of RhoBTB1 consisting of two BTB-domains (B1 & B2) and the C-terminal (C) domain of RhoBTB1 can deliver PDE5 to proteasomal pathway. The cellular expression of RhoBTB1 and CUL3 is ubiquitous whereas expression of PDE5 is cell specific. Moreover, vessel tone is regulated through NO-independent mechanisms. Therefore, we hypothesized that RhoBTB1 may have other interacting partners, potentially functioning as regulators of vessel tone and BP in vascular smooth muscle (VSM) cells, through a similar mode of binding as PDE5. Therefore, we utilized ascorbate peroxidase (APEX2) proximity labelling system comprising APEX2 tagged B1B2C domain (B1B2C-APEX2) to identify unknown potential regulators of vasomotor tone in RhoBTB1-CUL3 axis in A7R5 VSM cells. The background of the proteomic screen was minimized by utilizing APEX2-B1B2 which lacks the final C-terminal region of the protein and cannot bind PDE5. We validated the interaction of several identified proteins with RhoBTB1 and the B1B2C domains using co-immunoprecipitation (Co-IP). Our Co-IP data corroborated the proteomic screen as several proteins demonstrated differential interaction with B1B2C and B1B2. Among them, we examined RbFox2, a regulator of mRNA splicing for further investigation. Further data established that RbFox2 is upregulated under the following conditions: 1) pharmacological inhibition of the proteasomal pathway, 2) in CRISPR edited CUL3KO HEK293 cells, 3) in aorta of VSM cell-specific CUL3 deleted mice, 4) by siRNA mediated knock-down of RhoBTB1 in SMCs, and 5) in Ang-II treated SMCs and aorta of Ang-II treated animals. We hypothesized that RbFox2 could modulate actin and actinin-dependent cytoskeletal dynamics, an important regulator of arterial stiffness. First, Co-IP data suggest an interaction between RbFox2 and SMC-specific alpha actinin. Next, siRNA-mediated knock down of RbFox2 altered the actin and actinin-dependent cytoskeletal dynamics in SMCs. Collectively, this establishes the potential regulation of RbFox2 through the RhoBTB1-CUL3 proteasomal pathway and that RbFox2 may play a mechanistic role in arterial stiffness in hypertension. Funding: NIH R35 HL144807 (to Dr. Curt D. Sigmund). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Nitric oxide regulation of fetal and newborn lung development and function

In the developing lung, nitric oxide (NO) and cyclic guanosine monophosphate (cGMP) signaling are essential in regulating lung formation and vascular tone. Animal studies have linked many anatomical and pathophysiological features of newborn lung disease to abnormalities in the NO/cGMP signaling system. They have demonstrated that driving this system with agonists and antagonists alleviates many of them. This research has spurred the rapid clinical development, testing, and application of several NO/cGMP-targeting therapies with the hope of treating and potentially preventing significant pediatric lung diseases. However, there are instances when the therapeutic effectiveness of these agents is limited. Studies indicate that injury-induced disruption of several critical components within the signaling system may hinder the promise of some of these therapies. Recent research has identified basic mechanisms that suppress NO/cGMP signaling in the injured newborn lung. They have also pinpointed biomarkers that offer insight into the activation of these pathogenic mechanisms and their influence on the NO/cGMP signaling system's integrity in vivo. Together, these will guide the development of new therapies to protect NO/cGMP signaling and safeguard newborn lung development and function. This review summarizes the important role of the NO/cGMP signaling system in regulating pulmonary development and function and our evolving understanding of how it is disrupted by newborn lung injury.

NOS1AP Gene Variants and Their Role in Metabolic Syndrome: A Study of Patients with Schizophrenia.

Metabolic syndrome (MetS) is common among schizophrenia patients, and one of MetS's causes may be an imbalance in nitric oxide regulation. In this study, we examined associations of three polymorphic variants of the nitric oxide synthase 1 adapter protein (NOS1AP) gene with MetS in schizophrenia. NOS1AP regulates neuronal nitric oxide synthase, which controls intracellular calcium levels and may influence insulin secretion. The aim of the investigation was to study polymorphic variants of the NOS1AP gene as possible markers of MetS in patients with schizophrenia. A total of 489 Caucasian patients with schizophrenia (ICD-10) from Siberia (Russia) were included in the study, and 131 (26.8%) patients had MetS (IDF classification, 2007). The participants were genotyped for three single-nucleotide polymorphisms in NOS1AP (rs12143842, rs10494366, and rs12029454). Logistic regression was used for association analysis. Single-nucleotide polymorphisms, sex, and age served as covariates; the dependent variable was the coded parameter of the presence/absence of MetS. Polymorphisms rs12143842 and rs10494366 showed a stable association even after Bonferroni's correction for multiple comparisons (p = 0.005 and 0.002, respectively), indicating a statistically significant contribution of these polymorphic variants to the pathogenesis of MetS. Our results suggest that in patients with schizophrenia, NOS1AP may be involved in MetS pathophysiology.

Synergistic regulation of hydrogen sulfide and nitric oxide on biochemical components, exopolysaccharides, and nitrogen metabolism in nickel stressed rice field cyanobacteria.

The present study examined the regulatory mechanism of hydrogen sulfide (H2S) and nitric oxide (NO) in nickel (Ni) stressed cyanobacteria viz., Nostoc muscorum and Anabaena sp. by analyzing growth, photosynthetic pigments, biochemical components (protein and carbohydrate), exopolysaccharides (EPS), inorganic nitrogen content, and activity of enzymes comprised in nitrogen metabolism and Ni accumulation. The 1µM Ni substantially diminished growth by 18% and 22% in N. muscorum and Anabaena sp. respectively, along with declining the pigment contents (Chl a/Car ratio and phycobiliproteins), and biochemical components. It also exerted negative impacts on inorganic uptake of nitrate and nitrite contents; nitrate reductase and nitrite reductase; and ammonium assimilating enzymes (glutamine synthetase, glutamate synthase, and glutamate dehydrogenase exhibited a reverse trend) activities. Nonetheless, the adverse impact of Ni can be mitigated through the exogenous supplementation of NaHS [sodium hydrosulfide (8µM); H2S donor] and SNP [sodium nitroprusside (10µM); NO donor] which showed substantial improvement on growth, pigments, nitrogen metabolism, and EPS layer and noticeably occurred as a consequence of a substantial reduction in Ni accumulation content which minimized the toxicity effects. The accumulation of Ni on both the cyanobacterial cell surface (EPS layer) are confirmed by the SEM-EDX analysis. Further, the addition of NO scavenger (PTIO; 20µM) and inhibitor of NO (L-NAME; 100µM); and H2S scavenger (HT; 20µM) and H2S inhibitor (PAG; 50µM) reversed the positive responses of H2S and NO and damages were more prominent under Ni stress thereby, suggesting the downstream signaling of H2S on NO-mediated alleviation. Thus, this study concludes the crosstalk mechanism of H2S and NO in the mitigation of Ni-induced toxicity in rice field cyanobacteria.

Diurnal variation of cerebral blood flow in healthy humans under normal entrained conditions.

The presence of a circadian cycle of cerebral blood flow may have implications for the occurrence of daily variations in cerebrovascular events in humans, but how cerebral blood flow varies throughout the day and its mechanism are still unclear. The study aimed to explore the diurnal variation of cerebral blood flow in healthy humans and its possible mechanisms. Arterial spin labelling images were collected at six time-points (09:00 hours, 13:00 hours, 17:00 hours, 21:00 hours, 01:00 hours, 05:00 hours) from 18 healthy participants (22-39 years old; eight females) to analyse diurnal variations in cerebral blood flow. Resting heart rate and blood pressure at six time-points and blood indicators (20-hydroxyeicosatetraenoic acid, epoxyeicosatrienoic acids, prostaglandin E2, noradrenaline and nitric oxide) related to cerebral vascular tone at two time-points (09:00 hours and 21:00 hours) were collected to analyse possible influences on diurnal variations in cerebral blood flow. From 21:00 hours to 05:00 hours, parietal cortical relative cerebral blood flow tended to increase, while frontal cortical and cerebellar relative cerebral blood flow tended to decrease. There was a time-dependent negative correlation between parietal cortical relative cerebral blood flow and resting heart rate, whereas there was a time-dependent positive correlation between cerebellar relative cerebral blood flow and resting heart rate. The change of parietal cortical relative cerebral blood flow was positively correlated with the change of nitric oxide. There was also a time-dependent positive correlation between mean arterial pressure and mean whole-brain cerebral blood flow. The findings indicated that parietal cortical relative cerebral blood flow and frontal cortical/cerebellar relative cerebral blood flow showed roughly opposite trends throughout the day. The diurnal variations in relative cerebral blood flow were regional-specific. Diurnal variation of nitric oxide and neurogenic regulation may be potential mechanisms for diurnal variation in regional relative cerebral blood flow.

Regulation of nitric oxide by phytoglobins in Lotus japonicus is involved in mycorrhizal symbiosis with Rhizophagus irregularis

Various reactive molecular species are generated in plant–microbe interactions, and these species participate in defense and symbiotic responses. Leguminous plants successfully establish symbiosis by maintaining an appropriate level of nitric oxide (NO), which is generated in the roots and nodules during root nodule symbiosis. Phytoglobin (plant hemoglobin) controls NO levels in plants. In this study, we investigated mycorrhizal symbiosis, which occurs in more than 80% of land plants, between Rhizophagus irregularis and Lotus japonicus to clarify the involvement of phytoglobin-mediated NO regulation. The mycorrhizae of L. japonicus exhibited higher NO levels in the presence of R. irregularis than in its absence, especially at the infection site. LjGlb1–1, a phytoglobin that regulates NO level in L. japonicus, was upregulated during symbiosis with R. irregularis. In transformed hairy roots carrying the ProLjGlb1–1:GUS construct, LjGlb1–1 expression was observed at the R. irregularis infection site. We further examined the symbiotic phenotypes of L. japonicus lines with high and low LjGlb1–1 expression with R. irregularis. During mycorrhizal symbiosis, the high LjGlb1–1 expression line exhibited better growth than the wild-type, whereas the low expression line exhibited poor growth. In addition, the expression of LjPT4, a phosphate transporter specific to mycorrhizal symbiosis, was higher in the high LjGlb1–1 expression line, whereas that of the tubulin gene of R. irregularis was lower in the low LjGlb1–1 expression line than in the wild-type. These results confirm that NO regulation by LjGlb1–1 is involved in mycorrhizal symbiosis in L. japonicus, as it is reportedly in nitrogen-fixing symbiosis.

Regulation of renal nitric oxide and eNOS/iNOS expression by tadalafil participates in the mitigation of amphotericin B–induced renal injury: Down-regulation of NF-κB/iNOS/caspase-3 signaling

Amphotericin B (AmB)–induced acute kidney injury (AKI) is a common health problem having an undesirable impact on its urgent therapeutic utility for fatal systemic fungal infections. Tadalafil (TAD), a phosphodiesterase-5 (PDE-5) inhibitor, has been observed to have a wide range of pharmacological actions, including nephroprotection. The study’s objective was to examine the possible underlying protective mechanism of TAD against AmB-induced nephrotoxicity. Experimentally, animals were divided randomly into four groups: control, TAD (5 mg/kg/day; p.o.), AmB (18.5 mg/kg/day; i.p.), and TAD+AmB groups. Sera and tissue samples were processed for biochemical, molecular, and histological analyses. The biochemical investigations showed that TAD significantly ameliorated the increase of kidney function biomarkers (creatinine, urea, CysC, KIM-1) in serum, renal nitric oxide (NO), lipid peroxidation (MDA), and inflammatory cytokines (TNF-α, IL-6) in AmB-treated rats. Meanwhile, TAD significantly retarded AmB-induced decrease in serum magnesium, sodium, potassium, and renal glutathione content. Molecular analysis revealed that TAD reduced AmB-induced imbalance in the protein expression of eNOS/iNOS, which explains its regulatory effect on renal NO content. These results were also supported by the down-regulation of nuclear NF-κB p65 and cleaved caspase-3 protein expressions, as well as the improvement of histological features by TAD in AmB-treated rats. Therefore, it can be suggested that TAD could be a promising candidate for renoprotection against AmB-induced AKI. That could be partly attributed to its regulatory effect on renal eNOS/iNOS balance and NO, the inhibition of NF-κB p65 nuclear translocation, its downstream inflammatory cytokines and iNOS, and ultimately the inhibition of caspase-3-induced renal apoptosis.

Suboptimal zinc supply affects the S-nitrosoglutathione reductase enzyme and nitric oxide signaling in Arabidopsis

The S-nitrosoglutathione reductase (GSNOR), a key regulator of nitric oxide (NO) signaling, requires zinc (Zn) cofactors for its catalytic activity. Possible changes in GSNOR function and NO signaling due to limited Zn supply and participation of GSNOR in response to Zn deficiency have not yet been examined. The wild-type Arabidopsis thaliana seedlings (Col-0) and the overproducer of GSNOR (35S::FLAG-GSNOR1) were grown in agar medium supplemented with 15 µM (full Zn), 1.5 µM (Zn/10) and 0 µM (Zn0) zinc sulfate. Limited availability of Zn in the nutrient medium during the experimental period resulted in a significantly reduced Zn content in the roots and shoots of Arabidopsis and altered the expression of Zn deficiency marker genes; however, the Zn content did not reflect Zn deficiency in the seedlings. GSNOR has no effect on the Zn limitation-induced reduction in the in planta Zn content. Suboptimal Zn supply results in a smaller but more active GSNOR protein pool in Col-0 A. thaliana. In 35S::FLAG-GSNOR1, overproduction possibly compensates for the negative effects of reduced Zn supply, resulting in unchanged GSNOR expression, protein abundance, and activity. Suboptimal Zn supply alters NO but did not modify peroxynitrite and hydrogen peroxide levels and exerts a pronitrant effect in the plant proteome. Overall, this is the first report to show that limited Zn supply affects the GSNOR enzyme at the gene and protein levels but not at the activity level and modifies reactive species levels and physiological nitroproteome in Arabidopsis.

Nitric oxide and AMF-mediated regulation of soil enzymes activities, cysteine-H2S system and thiol metabolites in mitigating chromium (Cr (VI)) toxicity in pigeonpea genotypes.

Cr (VI) hampers plant growth and yield by reducing essential nutrient uptake as it competes for phosphate and sulfate transporters. Nitric oxide (NO) and mycorrhization play important roles in mitigating Cr (VI) toxicity. Present study aimed to compare the potential of AMF (Arbuscular mycorrhizal fungi)-Rhizoglomus intraradices and NO (0.25mM) in alleviating Cr (VI) stress (0, 10 and 20mg/kg) in two differentially tolerant pigeonpea genotypes (Pusa 2001 and AL 201). Cr (VI) toxicity reduced growth, mycorrhizal colonization, nutrient uptake, and overall productivity by inducing reactive oxygen species (ROS) generation, with AL 201 more sensitive than Pusa 2001. NO and AM enhanced activities of soil enzymes, thereby increasing nutrients availability as well as their uptake, with AM more effective than NO. Both amendments reduced oxidative stress and restricted Cr (VI) uptake by increasing the activities of antioxidant and S- assimilatory enzymes, with Pusa 2001 more responsive than AL 201. NO was relatively more efficient in regulating cysteine-H2S system by increasing the activities of biosynthetic enzymes (ATP-sulfurylase (ATPS), O-acetylserine thiol lyase (OASTL), D-cysteine desulfhydrase (DCD) and L-cysteine desulfhydrase (LCD), while AM significantly increased glutathione reductase (GR), γ-glutamylcysteine synthetase (γ-ECS) enzymes activities and resultant glutathione (GSH), phytochelatins (PCs), and non-protein thiols (NP-SH) synthesis. Moreover, co-application of NO and AM proved to be highly beneficial in negating the toxic effects of Cr (VI) due to functional complementarity between them. Study suggested the combined use of NO and AM as a useful strategy in re-establishing pigeonpea plants growing in Cr (VI)-stressed environments.

Red blood cell eNOS: a major player in regulating cardiovascular health.

Red blood cells (RBCs) have traditionally been seen as simple carriers of gases and nutrients in the body. One important non-canonical function of RBCs in the cardiovascular system is the regulation of nitric oxide (NO) metabolism. It was shown that RBCs can scavenge NO, transport NO metabolites, and produce NO in hypoxic conditions, thereby inducing hypoxic vasodilation. RBCs also express an endothelial nitric oxide synthase (eNOS). However, its physiological significance has been controversial for many years. This review article provides a comprehensive overview of the experimental research on RBC eNOS signaling in vivo. These data show that RBC eNOS signaling modulates intracellular NO production and NO-heme levels, as well as extracellular paracrine NO metabolite signaling, which contributes to regulating peripheral vascular resistance, blood pressure, and cardioprotection. Additionally, this article explores the potential intracellular molecular mechanisms and the implications of RBC eNOS in cardiovascular health and disease.

Involvement of NO in V-ATPase Regulation in Cucumber Roots under Control and Cadmium Stress Conditions.

Nitric oxide (NO) is a signaling molecule that participates in plant adaptation to adverse environmental factors. This study aimed to clarify the role of NO in the regulation of vacuolar H+-ATPase (V-ATPase) in the roots of cucumber seedlings grown under control and Cd stress conditions. In addition, the relationship between NO and salicylic acid (SA), as well as their interrelations with hydrogen sulfide (H2S) and hydrogen peroxide (H2O2), have been verified. The effect of NO on V-ATPase was studied by analyzing two enzyme activities, the expression level of selected VHA genes and the protein level of selected VHA subunits in plants treated with a NO donor (sodium nitroprusside, SNP) and NO biosynthesis inhibitors (tungstate, WO42- and N-nitro-L-arginine methyl ester, L-NAME). Our results indicate that NO functions as a positive regulator of V-ATPase and that this regulation depends on NO generated by nitrate reductase and NOS-like activity. It was found that the mechanism of NO action is not related to changes in the gene expression or protein level of the V-ATPase subunits. The results suggest that in cucumber roots, NO signaling interacts with the SA pathway and, to a lesser extent, with two other known V-ATPase regulators, H2O2 and H2S.

Indirect regeneration in Ficus lyrata Warb. and metabolite profiles influenced by nitric oxide and Plant growth regulators

BackgroundTo establish an indirect regeneration protocol in Ficus lyrata, a three-phase experiment (callus induction, morphogenic callus induction, and plant regeneration) based on auxin, cytokinin, and nitric oxide interactions was designed and implemented using leaf explants. The metabolite profiles (amino acid profile, total phenolic content, total soluble sugars, and total antioxidant activity) alteration patterns were also investigated to determine the metabolites contributing to the progress of each phase.ResultsResults demonstrated that 11 out of 48 implemented treatments resulted in morphogenic callus induction (morphogenic treatments), and nitric oxide played a key role in increasing efficiency from 13 to 100%. More importantly, nitric oxide cross-talk with cytokinins was necessary for shoot regeneration from morphogenic calli. Only 4 out of all 48 implemented treatments were capable of shoot regeneration (regenerative treatments), and among them, PR42 treatment led to the highest shoot regeneration rate (86%) and maximum mean number of shoot/explant (10.46). Metabolite analyses revealed that the morphogenic and regenerative treatments followed similar metabolite alterations, which were associated with increased biosynthesis of arginine, lysine, methionine, asparagine, glutamine, histidine, threonine, leucine, glycine, serine amino acids, total soluble sugars content, and total antioxidant activity. On the contrary, non-morphogenic and non-regenerative treatments caused the accumulation of a significantly greater total phenolic content and malondialdehyde in the explant cells, which reflexed the stressful condition of the explants.ConclusionsIt could be concluded that the proper interactions of auxin, cytokinins, and nitric oxide could result in metabolite biosynthesis alterations, leading to triggering cell proliferation, morphogenic center formation, and shoot regeneration.

Nitric Oxide (NO) regulation of Dendritic cells (DC) metabolism and immune effector functions

Abstract Dendritic cell (DC) activation is characterized by a sustained commitment to glycolysis, a requirement for survival in DC subsets expressing inducible nitric oxide synthase (iNOS, encoded by Nos2 gene). Nitric oxide (NO) can mediate both host-protective and host-cytotoxic effects by interfering with pathogen replication and/or by inhibiting the host mitochondrial respiration, resulting in metabolic rewiring in DCs. These phenomena primarily have been studied in DCs from the classic laboratory inbred mouse strain C57BL/6J (B6), where DCs experience a loss of mitochondrial function due to NO accumulation. To assess the conservation of NO-driven metabolic regulation in DCs, we compared B6 mice to the wild-derived genetically divergent PWD/PhJ (PWD) strain. We show preserved mitochondrial respiration and enhanced post-activation survival in LPS-stimulated PWD DCs due to attenuated NO production. To genetically map PWD’s NO phenotype, we used a congenic mouse strain (B6.PWD-Chr11.2; 11.2) that carries a PWD-derived portion of chromosome 11, including Nos2, on a B6 background. The 11.2 DCs show comparable iNOS expression with lower NO production levels than B6 DCs. We demonstrate that activated 11.2 DCs maintain mitochondrial respiration and TCA cycle carbon flux, compared with B6 DCs. However, reduced NO production by the PWD Nos2 allele results in impaired cellular control of Listeria monocytogenes replication. These studies establish a natural genetic model for restrained endogenous NO production and suggest a useful model to investigate the contribution/regulation of NO in DC metabolism and immune function. This work was supported by the National Institutes of Health (NIH), National Institute of Allergy and Infectious Diseases (P30GM118228, 1R21AI135385-01A, T32AI055402-15, and R21 AI145306), the NIH, National Institute of Neurological Disorders and Stroke (R01 NS097596), and the National Multiple Sclerosis Society (RG-1901-33309).