ABSTRACT
INTRODUCTION: Azelnidipine, a selective calcium channel blocker, effectively lowers blood pressure (BP) and heart rate (HR) in hypertensive patients, as demonstrated in a retrospective real-world evidence (RWE) study in Indian patients. MATERIALS AND METHODS: This was a retrospective cohort study that included 882 patients aged 18 years or older who had been on azelnidipine treatment for the last 3 months for mild to moderate hypertension (HTN). A structured proforma was utilized to gather data from prescribing physicians to assess the efficacy of azelnidipine (8 and 16 mg) as monotherapy or in combination with other antihypertensive drugs. The primary endpoints of the study were to capture changes in systolic blood pressure (SBP) and diastolic BP (DBP) from baseline to the subsequent visits (4 and 12 weeks), while the secondary endpoints were to measure similar changes in the diabetic group and to estimate the proportion of patients achieving target BP of <130/80 mm Hg and <140/90 mm Hg, respectively. RESULTS: The overall mean reduction of systolic/diastolic BP from baseline to 12 weeks was 13.92/7.91 mm Hg (p-value < 0.0001). The mean reduction of systolic/diastolic BP from baseline to 12 weeks was 11.77/7.43 mm Hg (p-value < 0.0001) in newly diagnosed HTN patients, while in known cases of HTN, it was 16.50/8.48 mm Hg (p-value < 0.0001). In the diabetic group, the mean reduction was 15.35/8.69 mm Hg (p-value < 0.0001). Overall the study showed that in 44 (4.99%) and 408 (46.26%) patients, target BP of <130/80 mm Hg and <140/90 mm Hg, respectively was achieved. The mean change in HR from baseline was a reduction of 5.22 beats/minute. CONCLUSION: Azelnidipine can be an effective antihypertensive drug to treat mild to moderate HTN in Indian patients.
Subject(s)
Antihypertensive Agents , Azetidinecarboxylic Acid , Blood Pressure , Calcium Channel Blockers , Dihydropyridines , Hypertension , Humans , Dihydropyridines/therapeutic use , Azetidinecarboxylic Acid/analogs & derivatives , Azetidinecarboxylic Acid/therapeutic use , Retrospective Studies , Hypertension/drug therapy , Male , Calcium Channel Blockers/therapeutic use , Female , Middle Aged , India , Antihypertensive Agents/therapeutic use , Blood Pressure/drug effects , Adult , Aged , Treatment OutcomeABSTRACT
A spectrofluorimetric method using fluorescent carbon dots (CDs) was developed for the selective detection of azelnidipine (AZEL) pharmaceutical in the presence of other drugs. In this study, N-doped CDs (N-CDs) were synthesized through a single-step hydrothermal process, using citric acid and urea as precursor materials. The prepared N-CDs showed a highly intense blue fluorescence emission at 447 nm, with a photoluminescence quantum yield of ~21.15% and a fluorescence lifetime of 0.47 ns. The N-CDs showed selective fluorescence quenching in the presence of all three antihypertensive drugs, which was used as a successful detection platform for the analysis of AZEL. The photophysical properties, UV-vis light absorbance, fluorescence emission, and lifetime measurements support the interaction between N-CDs and AZEL, leading to fluorescence quenching of N-CDs as a result of ground-state complex formation followed by a static fluorescence quenching phenomenon. The detection platform showed linearity in the range 10-200 µg/ml (R2 = 0.9837). The developed method was effectively utilized for the quantitative analysis of AZEL in commercially available pharmaceutical tablets, yielding results that closely align with those obtained from the standard method (UV spectroscopy). With a score of 0.76 on the 'Analytical GREEnness (AGREE)' scale, the developed analytical method, incorporating 12 distinct green analytical chemistry components, stands out as an important technique for estimating AZEL.
Subject(s)
Azetidinecarboxylic Acid , Carbon , Dihydropyridines , Quantum Dots , Spectrometry, Fluorescence , Dihydropyridines/analysis , Dihydropyridines/chemistry , Carbon/chemistry , Azetidinecarboxylic Acid/analysis , Azetidinecarboxylic Acid/analogs & derivatives , Azetidinecarboxylic Acid/chemistry , Quantum Dots/chemistry , Green Chemistry Technology , Tablets/analysis , Fluorescent Dyes/chemistry , Pharmaceutical Preparations/chemistry , Pharmaceutical Preparations/analysis , Molecular StructureABSTRACT
A succinct synthetic approach to mugineic acids and 2'-hydroxynicotianamine was established. Unlike all other synthetic methods, this approach utilized epoxide ring-opening reactions to form two C-N bonds and is characterized by the absence of redox reactions. Mugineic acid was synthesized from three readily available fragments on a gram scale in 6 steps. The protected 2'-hydroxynicotianamine was also synthesized in 4 steps, and the dansyl group, serving as a fluorophore, was introduced through a click reaction after propargylation of the 2'-hydroxy group. The dansyl-labeled nicotianamine (NA) iron complexes were internalized by oocytes overexpressing ZmYS1 (from maize) or PAT1 (from human) transporters, indicating successful transport of the synthesized NA-probe through these transporters.
Subject(s)
Azetidinecarboxylic Acid/analogs & derivatives , Epoxy Compounds , Epoxy Compounds/chemistry , Epoxy Compounds/metabolism , Humans , Molecular Structure , Azetidinecarboxylic Acid/metabolism , Azetidinecarboxylic Acid/chemistryABSTRACT
Nicotianamine (NA) plays a crucial role in transporting metal ions, including iron (Fe), in plants; therefore, NICOTIANAMINE SYNTHASE (NAS) genes, which control NA synthesis, are tightly regulated at the transcriptional level. However, the transcriptional regulatory mechanisms of NAS genes require further investigations. In this study, we determined the role of bZIP44 in mediating plant response to Fe deficiency stress by conducting transformation experiments and assays. bZIP44 positively regulated the response of Arabidopsis to Fe deficiency stress by interacting with MYB10 and MYB72 to enhance their abilities to bind at NAS2 and NAS4 promoters, thereby increasing NAS2 and NAS4 transcriptional levels and promote NA synthesis. In summary, the transcription activities of bZIP44, MYB10, and MYB72 were induced in response to Fe deficiency stress, which enhanced the interaction between bZIP44 and MYB10 or MYB72 proteins, synergistically activated the transcriptional activity of NAS2 and NAS4, promoted NA synthesis, and improved Fe transport, thereby enhancing plant tolerance to Fe deficiency stress.
Subject(s)
Arabidopsis Proteins , Arabidopsis , Basic-Leucine Zipper Transcription Factors , Gene Expression Regulation, Plant , Iron , Stress, Physiological , Alkyl and Aryl Transferases/metabolism , Alkyl and Aryl Transferases/genetics , Arabidopsis/genetics , Arabidopsis/metabolism , Arabidopsis Proteins/metabolism , Arabidopsis Proteins/genetics , Azetidinecarboxylic Acid/analogs & derivatives , Azetidinecarboxylic Acid/metabolism , Basic-Leucine Zipper Transcription Factors/metabolism , Basic-Leucine Zipper Transcription Factors/genetics , Iron/metabolism , Plants, Genetically Modified , Promoter Regions, Genetic/genetics , Protein Binding , Stress, Physiological/geneticsABSTRACT
In this study, a physiologically based pharmacokinetic (PBPK) model of the cytochrome P450 3A (CYP3A) substrate azelnidipine was developed using in vitro and clinical data to predict the effects of azole antifungals on azelnidipine pharmacokinetics. Modeling and simulations were conducted using the Simcyp™ PBPK simulator. The azelnidipine model consisted of a full PBPK model and a first-order absorption model. CYP3A was assumed as the only azelnidipine elimination route, and CYP3A clearance was optimized using the pharmacokinetic profile of single-dose 5-mg azelnidipine in healthy participants. The model reproduced the results of a clinical drug-drug interaction study and met validation criteria. PBPK model simulations using azole antifungals (itraconazole, voriconazole, posaconazole, fluconazole, fosfluconazole) and azelnidipine or midazolam (CYP3A index substrate) were performed. Increases in the simulated area under the plasma concentration-time curve from time zero extrapolated to infinity with inhibitors were comparable between azelnidipine (range, 2.11-6.47) and midazolam (range, 2.26-9.22), demonstrating that azelnidipine is a sensitive CYP3A substrate. Increased azelnidipine plasma concentrations are expected when co-administered with azole antifungals, potentially affecting azelnidipine safety. These findings support the avoidance of azole antifungals in patients taking azelnidipine and demonstrate the utility of PBPK modeling to inform appropriate drug use.
Subject(s)
Antifungal Agents , Azetidinecarboxylic Acid/analogs & derivatives , Dihydropyridines , Midazolam , Humans , Midazolam/pharmacokinetics , Cytochrome P-450 CYP3A Inhibitors/pharmacology , Cytochrome P-450 CYP3A , Drug Interactions , Itraconazole , Models, BiologicalABSTRACT
Increased blood pressure variability (BPV) was shown to be associated with cardiovascular morbidities and/or mortalities. There are various types of BPV depending on time intervals of BP measurements, ranging from beat-to-beat to visit-to-visit or year-to-year. We previously found that continuous infusion of noradrenaline (NA) for 14 days increased short-term BPV every 15 min in rats. The aims of this study were to examine (1) whether NA infusion increases very short-term beat-to-beat BPV, (2) the effects of azelnidipine and hydralazine on NA-induced BPV, and (3) whether baroreceptor reflex sensitivity (BRS) is affected by NA or NA plus those vasodilators. Nine-week-old Wistar rats infused subcutaneously with 30 µg/h NA were orally treated with or without 9.7 mg/day azelnidipine or 5.9 mg/day hydralazine over 14 days. BP levels were continuously monitored via abdominal aortic catheter with a telemetry system in an unrestrained condition. Standard deviations (SDs) were used to evaluate beat-to-beat BPV and BPV every 15 min which was obtained by averaging BP levels for 10-s segment at each time point. BRS was determined by a sequence analysis. Continuous NA infusion over 14 days increased average BP, beat-to-beat BPV, and BPV every 15 min, lowering BRS. Comparing the two vasodilators, hydralazine reduced BP elevation by NA; meanwhile, azelnidipine alleviated BPV augmentation, preserving BRS, despite a smaller BP reduction. Thus, NA infusion increased both very short- and short-term BPV concomitantly with impaired BRS, while azelnidipine had an inhibitory effect, possibly independent of BP-lowering, on those types of BPV and impairment of BRS.
Subject(s)
Azetidinecarboxylic Acid/analogs & derivatives , Dihydropyridines , Norepinephrine , Vasodilator Agents , Rats , Animals , Blood Pressure , Vasodilator Agents/pharmacology , Norepinephrine/pharmacology , Rats, Wistar , Hydralazine/pharmacologyABSTRACT
Flaviviruses, represented by Zika and dengue virus (ZIKV and DENV), are widely present around the world and cause various diseases with serious consequences. However, no antiviral drugs have been clinically approved for use against them. Azelnidipine (ALP) is a dihydropyridine calcium channel blocker and has been approved for use as an antihypertensive drug. In the present study, ALP was found to show potent anti-flavivirus activities in vitro and in vivo. ALP effectively prevented the cytopathic effect induced by ZIKV and DENV and inhibited the production of viral RNA and viral protein in a dose-dependent manner. Moreover, treatment with 0.3 mg/kg of ALP protected 88.89% of mice from lethal challenge. Furthermore, using the time-of-drug-addition assay, the enzymatic inhibition assay, the molecular docking, and the surface plasmon resonance assay, we revealed that ALP acted at the replication stage of the viral infection cycle by targeting the viral RNA-dependent RNA polymerase. These findings highlight the potential for the use of ALP as an antiviral agent to combat flavivirus infections.
Subject(s)
Dengue , Dihydropyridines , Flavivirus Infections , Flavivirus , Zika Virus Infection , Zika Virus , Animals , Antiviral Agents/metabolism , Antiviral Agents/pharmacology , Azetidinecarboxylic Acid/analogs & derivatives , Dengue/drug therapy , Dihydropyridines/metabolism , Dihydropyridines/pharmacology , Flavivirus/physiology , Mice , Molecular Docking Simulation , RNA-Dependent RNA Polymerase , Zika Virus/physiology , Zika Virus Infection/drug therapyABSTRACT
Nicotianamine (NA) is one of the metal-chelating molecules found in higher plants in abundance. Synthesized by the enzyme nicotianamine synthase, NA has a major role in the transport of iron in plant tissues. This research paper deals with the coordination chemistry of the possible complexes of NA, [FeII (NA)]-, and [FeIII (NA)] in detail, from a theoretical standpoint. The chemical computations on the [FeII (NA)]- and [FeIII (NA)] complexes show that NA can bind with both Fe (+ 2) and Fe (+ 3) ions. The calculations confirm that the [FeIII (NA)] is thermodynamically more stable in comparison with [FeII (NA)]-, while [FeII (NA)]- is kinetically more stable than [FeIII (NA)]. Under the physiological conditions prevailing in plant tissues, [FeIII (NA)] can undergo reduction, but the auto-oxidation of [FeII (NA)]- to [FeIII (NA)] is prevented. In summary, NA can translocate Fe ions within plant tissues, wherever required, both as Fe (+ 2) and Fe (+ 3) complexes.
Subject(s)
Azetidinecarboxylic Acid , Iron , Azetidinecarboxylic Acid/analogs & derivatives , Azetidinecarboxylic Acid/chemistry , Azetidinecarboxylic Acid/metabolism , Iron/metabolism , Models, Theoretical , PlantsABSTRACT
BACKGROUND: Nicotianamine (NA), 2'-deoxymugineic acid (DMA), and mugineic acid (MA) are chelators required for iron uptake and transport in plants. Nicotianamine aminotransferase (NAAT), 2'-deoxymugineic acid synthase (DMAS), transporter of MAs (TOM), and efflux transporter of NA (ENA) are involved in iron uptake and transport in rice (Oryza sativa), wheat (Triticum aestivum), and barley (Hordeum vulgare); however, these families have not been fully identified and comprehensively analyzed in maize (Zea mays L.). RESULTS: Here, we identified 5 ZmNAAT, 9 ZmDMAS, 11 ZmTOM, and 2 ZmENA genes by genome mining. RNA-sequencing and quantitative real-time PCR analysis revealed that these genes are expressed in various tissues and respond differently to high and low iron conditions. In particular, iron deficiency stimulated the expression of ZmDMAS1, ZmTOM1, ZmTOM3, and ZmENA1. Furthermore, we determined protein subcellular localization by transient expression of green fluorescent protein fusions in maize mesophyll protoplasts. ZmNAAT1, ZmNAAT-L4, ZmDMAS1, and ZmDMAS-L1 localized in the cytoplasm, whereas ZmTOMs and ZmENAs targeted to plasma and tonoplast membranes, endomembranes, and vesicles. CONCLUSIONS: Our results suggest that the different gene expression profiles and subcellular localizations of ZmNAAT, ZmDMAS, ZmTOM, and ZmENA family members may enable specific regulation of phytosiderophore metabolism in different tissues and under different external conditions, shedding light on iron homeostasis in maize and providing candidate genes for breeding iron-rich maize varieties.
Subject(s)
Genome, Plant/genetics , Iron/metabolism , Multigene Family/genetics , Plant Proteins/genetics , Zea mays/genetics , Azetidinecarboxylic Acid/analogs & derivatives , Azetidinecarboxylic Acid/metabolism , Biological Transport , Chromosomes, Plant/genetics , Gene Expression Regulation, Plant , Genes, Reporter , Homeostasis , Iron Deficiencies , Phylogeny , Plant Proteins/metabolism , Protein Transport , Recombinant Fusion Proteins , Siderophores/metabolism , Transaminases/genetics , Transaminases/metabolism , Zea mays/enzymology , Zea mays/physiologyABSTRACT
The Yang cycle is involved in many essential metabolic pathways in plant growth and development. As extended products of the Yang cycle, the function and regulation network of ethylene and polyamines are well characterized. Nicotianamine (NA) is also a product of this cycle and works as a key metal chelator for iron (Fe) homeostasis in plants. However, interactions between the Yang cycle and NA biosynthesis remain unclear. Here, we cloned maize interveinal chlorosis 1 (mic1), encoding a 5'-methylthioadenosine nucleosidase (MTN), that is essential for 5'-methylthioadenosine (MTA) salvage and NA biosynthesis in maize (Zea mays). A single base G-A transition in the fourth exon of mic1 causes a Gly to Asp change, resulting in increased MTA, reduced Fe distribution, and growth retardation of seedlings. Knockout of ZmMIC1 but not its paralog ZmMTN2 by CRISPR/Cas9 causes interveinal chlorosis, indicating ZmMIC1 is mainly responsible for MTN activity in maize. Transcriptome analysis showed a typical response of Fe deficiency. However, metabolic analysis revealed dramatically reduced NA content in mic1, suggesting NA biosynthesis was impaired in the mutant. Exogenous application of NA transiently reversed the interveinal chlorosis phenotype of mic1 seedlings. Moreover, the mic1 mutant overexpressing a NA synthase gene not only recovered from interveinal chlorosis and growth retardation but was also fertile. These findings provide a link between the Yang cycle and NA biosynthesis, which highlights an aspect of Fe homeostasis regulation in maize.
Subject(s)
Anemia, Hypochromic , Zea mays , Azetidinecarboxylic Acid/analogs & derivatives , Azetidinecarboxylic Acid/metabolism , Gene Expression Regulation, Plant , Homeostasis , Zea mays/genetics , Zea mays/metabolismABSTRACT
Conventional breeding efforts for iron (Fe) and zinc (Zn) biofortification of bread wheat (Triticum aestivum L.) have been hindered by a lack of genetic variation for these traits and a negative correlation between grain Fe and Zn concentrations and yield. We have employed genetic engineering to constitutively express (CE) the rice (Oryza sativa) nicotianamine synthase 2 (OsNAS2) gene and upregulate biosynthesis of two metal chelators - nicotianamine (NA) and 2'-deoxymugineic acid (DMA) - in bread wheat, resulting in increased Fe and Zn concentrations in wholemeal and white flour. Here we describe multi-location confined field trial (CFT) evaluation of a low-copy transgenic CE-OsNAS2 wheat event (CE-1) over 3 years and demonstrate higher concentrations of NA, DMA, Fe, and Zn in CE-1 wholemeal flour, white flour, and white bread and higher Fe bioavailability in CE-1 white flour relative to a null segregant (NS) control. Multi-environment models of agronomic and grain nutrition traits revealed a negative correlation between grain yield and grain Fe, Zn, and total protein concentrations, yet no correlation between grain yield and grain NA and DMA concentrations. White flour Fe bioavailability was positively correlated with white flour NA concentration, suggesting that NA-chelated Fe should be targeted in wheat Fe biofortification efforts.
Subject(s)
Oryza , Triticum , Azetidinecarboxylic Acid/analogs & derivatives , Bread/analysis , Edible Grain/metabolism , Flour/analysis , Oryza/genetics , Oryza/metabolism , Plant Breeding , Triticum/genetics , Triticum/metabolism , Zinc/metabolismABSTRACT
Strategies boosting both innate and adaptive immunity have great application prospects in cancer immunotherapy. Antibodies dual blocking the innate checkpoint CD47 and adaptive checkpoint PD-L1 or TIGIT could achieve durable anti-tumor effects. However, a small molecule dual blockade of CD47/SIRPα and TIGIT/PVR pathways has not been investigated. Here, an elevated expression of CD47 and PVR was observed in tumor tissues and cell lines analyzed with the GEO datasets and by flow cytometry, respectively. Compounds approved by the FDA were screened with the software MOE by docking to the potential binding pockets of SIRPα and PVR identified with the corresponding structural analysis. The candidate compounds were screened by blocking and MST binding assays. Azelnidipine was found to dual block CD47/SIRPα and TIGIT/PVR pathways by co-targeting SIRPα and PVR. In vitro, azelnidipine could enhance the macrophage phagocytosis when co-cultured with tumor cells. In vivo, azelnidipine alone or combined with irradiation could significantly inhibit the growth of MC38 tumors. Azelnidipine also significantly inhibits the growth of CT26 tumors, by enhancing the infiltration and function of CD8+ T cell in tumor and systematic immune response in the tumor-draining lymph node and spleen in a CD8+ T cell dependent manner. Our research suggests that the anti-hypertensive drug azelnidipine could be repositioned for cancer immunotherapy.
Subject(s)
Azetidinecarboxylic Acid/analogs & derivatives , Dihydropyridines/pharmacology , Drug Repositioning/methods , Gene Expression Regulation, Neoplastic/drug effects , Immunotherapy/methods , Neoplasms/therapy , Animals , Azetidinecarboxylic Acid/pharmacology , CD47 Antigen/antagonists & inhibitors , Calcium Channel Blockers/pharmacology , Cell Line, Tumor , Cricetinae , Disease Models, Animal , Humans , Immunity, Innate , Mice , Mice, Inbred BALB C , Mice, Inbred C57BL , Molecular Targeted Therapy , Neoplasms/immunology , Neoplasms/metabolism , Neoplasms/pathology , Receptors, Immunologic/antagonists & inhibitors , Receptors, Virus/antagonists & inhibitors , T-Lymphocytes/drug effectsABSTRACT
The nicotianamine-iron chelate [NA-Fe2+], which is found in many plant-based foods, has been recently described as a new form of bioavailable iron in mice and chickens. How NA-Fe2+ is assimilated from the diet, however, remains unclear. The current investigation by Murata et al. has identified the proton-coupled amino acid transporter 1 (PAT1) as the main mechanism by which NA-Fe2+ is absorbed in the mammalian intestine. Discovery of this new form of dietary iron and elucidation of its pathway of intestinal absorption may lead to the development of improved iron supplementation approaches.
Subject(s)
Amino Acid Transport Systems/metabolism , Azetidinecarboxylic Acid/analogs & derivatives , Iron Chelating Agents/metabolism , Symporters/metabolism , Animals , Azetidinecarboxylic Acid/metabolism , Intestinal Absorption , Iron, Dietary/metabolism , Mice , XenopusABSTRACT
Iron (Fe) is an essential nutrient, but is poorly bioavailable because of its low solubility in alkaline soils; this leads to reduced agricultural productivity. To overcome this problem, we first showed that the soil application of synthetic 2'-deoxymugineic acid, a natural phytosiderophore from the Poaceae, can recover Fe deficiency in rice grown in calcareous soil. However, the high cost and poor stability of synthetic 2'-deoxymugineic acid preclude its agricultural use. In this work, we develop a more stable and less expensive analog, proline-2'-deoxymugineic acid, and demonstrate its practical synthesis and transport of its Fe-chelated form across the plasma membrane by Fe(III)â¢2'-deoxymugineic acid transporters. Possibility of its use as an iron fertilizer on alkaline soils is supported by promotion of rice growth in a calcareous soil by soil application of metal free proline-2'-deoxymugineic acid.
Subject(s)
Azetidinecarboxylic Acid/analogs & derivatives , Fertilizers , Iron/chemistry , Azetidinecarboxylic Acid/chemistry , Siderophores/chemistry , Soil/chemistryABSTRACT
AIMS: Azelnidipine, a third-generation dihydropyridine calcium channel blocker (DHP CCB), has a characteristic hypotensive effect that persists even after it has disappeared from the plasma, which is thought to be due to its high hydrophobicity. However, because azelnidipine is unique, it might have other unknown effects on L-type Cav1.2 channels that result in the long-lasting decrease of blood pressure. The aim of this study was to investigate the potential quantitative modification of Cav1.2 by azelnidipine. MAIN METHODS: HEK293 cells were used to express Cav1.2 channels. Immunocytochemical analysis was performed to detect changes in the surface expression of the pore-forming subunit of the Cav1.2 channel, Cav1.2α1c. Western blotting analysis was performed to evaluate changes in expression levels of total Cav1.2α1c and Cavß2c. KEY FINDINGS: The surface expression of Cav1.2α1c was markedly reduced by treatment with azelnidipine, but not with other DHP CCBs (amlodipine and nicardipine). Results obtained with a dynamin inhibitor and an early endosome marker suggested that the reduction of surface Cav1.2α1c was not likely caused by internalization. Azelnidipine reduced the total amount of Cav1.2α1c protein in HEK293 cells and rat pulmonary artery smooth muscle cells. The reduction of Cav1.2α1c was rescued by inhibiting proteasome activity. In contrast, azelnidipine did not affect the amount of auxiliary Cavß2c subunits that function as a chaperone of Cav1.2. SIGNIFICANCE: This study is the first to demonstrate that azelnidipine reduces the expression of Cav1.2α1c, which might partly explain its long-lasting hypotensive effect.
Subject(s)
Azetidinecarboxylic Acid/analogs & derivatives , Calcium Channel Blockers/pharmacology , Calcium Channels, L-Type/metabolism , Dihydropyridines/pharmacology , Gene Expression Regulation/drug effects , Muscle, Smooth, Vascular/metabolism , Pulmonary Artery/metabolism , Animals , Azetidinecarboxylic Acid/pharmacology , Calcium Channels, L-Type/chemistry , Cells, Cultured , HEK293 Cells , Humans , Muscle, Smooth, Vascular/drug effects , Pulmonary Artery/drug effects , RatsABSTRACT
Coconut water (Cocos Nucifera) is shown to be a source of essential elements present in the form of low-molecular weight stable complexes known for their bio-availability. The total element concentrations were in the range of 0.2-2.7, 0.3-1, 3-14 and 0.5-2 ppm for Fe, Cu, Mn, and Zn, respectively, and varied as a function of the origin of the nut and its maturity. Speciation was investigated by size-exclusion chromatography - inductively coupled plasma mass spectrometry (ICPMS), and hydrophilic interaction liquid chromatography (HILIC) - electrospray-OrbitrapMS. The metal species identified included: iron complexes with citrate and malate: FeIII(Cit)3(Mal), FeIII(Cit)2(Mal)2, FeIII(Mal)2, glutamine: FeIII(Glu)2 and nicotianamine: FeII(NA); copper complexes with phenylanine: CuII(Phe)2 and CuII(Phe)3 and nicotianamine: CuII(NA); zinc complexes with citrate: ZnII(Cit)2 and nicotianamine ZnII(NA) and manganese complex with asparagine MnII(Asp)2. The contributions of the individual species to the total elements concentrations could be estimated by HILIC - ICP MS.
Subject(s)
Cocos/chemistry , Fruit and Vegetable Juices/analysis , Metals/analysis , Trace Elements/analysis , Trace Elements/chemistry , Azetidinecarboxylic Acid/analogs & derivatives , Azetidinecarboxylic Acid/analysis , Azetidinecarboxylic Acid/chemistry , Chromatography, Gel , Chromatography, Liquid , Citric Acid/analysis , Citric Acid/chemistry , Food Analysis/methods , Malates/analysis , Malates/chemistry , Metals/chemistry , Molecular Weight , Spectrometry, Mass, Electrospray IonizationABSTRACT
This work reports on the concise total synthesis of eight natural products of the mugineic acid and avenic acid families (phytosiderophores). An innovative "east-to-west" assembly of the trimeric products resulted in a high degree of divergence enabling the formation of the final products in just 10 or 11â steps each with a minimum of overall synthetic effort. Chiral pool starting materials (l-malic acid, threonines) were employed for the outer building blocks while the middle building blocks were accessed by diastereo- and enantioselective methods. A highlight of this work consists in the straightforward preparation of epimeric hydroxyazetidine amino acids, useful building blocks on their own, enabling the first synthesis of 3''-hydroxymugineic acid and 3''-hydroxy-2'-deoxymugineic acid.
Subject(s)
Azetidinecarboxylic Acid/analogs & derivatives , Biological Products/chemistry , Biological Products/chemical synthesis , Plants/chemistry , Siderophores/chemical synthesis , Azetidinecarboxylic Acid/chemical synthesis , Azetidinecarboxylic Acid/chemistry , Malates/chemistry , Siderophores/chemistry , Threonine/chemistryABSTRACT
Iron is an essential metal for all living organisms that is absorbed in the intestinal cells as a heme-chelated or free form. It is unclear how important plant-derived chelators, such as nicotianamine (NA), an organic small molecule that is ubiquitous in crops, vegetables, and various other foods, contribute to iron bioavailability in mammals. We performed electrophysiological assays with Xenopus laevis oocytes and radioactive tracer experiments with Caco-2 cells. The findings revealed that the proton-coupled amino acid transporter SLC36A1 (PAT1) transports iron in the form of NA-Fe (II) complex in vitro. Decreased expression of hPAT1 by RNA interference in Caco-2 cells reduced the uptake of NA-59Fe (II) complex. The uptake of inorganic 59Fe (II) was relatively unaffected. These results imply that PAT1 transports iron as a NA-Fe (II) complex. The rate of 59Fe absorption in the spleen, liver, and kidney was higher when mice were orally administered NA-59Fe (II) compared with free 59Fe (II). The profile of site-specific PAT1 expression in the mouse intestine coincided with those of NA and iron contents, which were the highest in the proximal jejunum. Orally administered NA-59Fe (II) complex in mice was detected in the proximal jejunum by thin layer chromatography. In contrast, much less 59Fe (or NA) was detected in the duodenum, where the divalent metal transporter SLC11A2 (DMT1) absorbs free Fe (II). The collective results revealed the role of PAT1 in NA-Fe (II) absorption in the intestine and potential implication of NA in iron uptake in mammals.
Subject(s)
Azetidinecarboxylic Acid/analogs & derivatives , Chelating Agents/pharmacology , Intestine, Small/drug effects , Intestine, Small/metabolism , Iron/metabolism , Animals , Azetidinecarboxylic Acid/pharmacology , Biological Availability , Biological Transport/drug effects , Cells, Cultured , Duodenum/drug effects , Duodenum/metabolism , Humans , Intestinal Absorption/drug effects , Jejunum/drug effects , Jejunum/metabolism , Male , Mice , Mice, Inbred ICR , Phytochemicals/pharmacology , Xenopus laevisABSTRACT
In several cultivation areas, grapevine can suffer from Fe chlorosis due to the calcareous and alkaline nature of soils. This plant species has been described to cope with Fe deficiency by activating Strategy I mechanisms, hence increasing root H+ extrusion and ferric-chelate reductase activity. The degree of tolerance exhibited by the rootstocks has been reported to depend on both reactions, but to date, little emphasis has been given to the role played by root exudate extrusion. We studied the behaviour of two hydroponically-grown, tolerant grapevine rootstocks (Ramsey and 140R) in response to Fe deficiency. Under these experimental conditions, the two varieties displayed differences in their ability to modulate morpho-physiological parameters, root acidification and ferric chelate reductase activity. The metabolic profiling of root exudates revealed common strategies for Fe acquisition, including ones targeted at reducing microbial competition for this micronutrient by limiting the exudation of amino acids and sugars and increasing instead that of Fe(III)-reducing compounds. Other modifications in exudate composition hint that the two rootstocks cope with Fe shortage via specific adjustments of their exudation patterns. Furthermore, the presence of 3-hydroxymugenic acid in these compounds suggests that the responses of grapevine to Fe availability are rather diverse and much more complex than those usually described for Strategy I plants.
Subject(s)
Iron/metabolism , Micronutrients/metabolism , Nutritional Physiological Phenomena/physiology , Plant Physiological Phenomena , Plant Roots/metabolism , Plant Roots/physiology , Vitis/metabolism , Vitis/physiology , Azetidinecarboxylic Acid/analogs & derivatives , Iron Chelating Agents/metabolism , Soil/chemistryABSTRACT
Nicotianamine (NA) is a metabolite synthesized by all plants, in which it is involved in the homeostasis of different micronutrients such as iron, nickel or zinc. In some plants it also serves as a precursor of phytosiderophores, which are used for extracellular iron scavenging. Previous studies have also established the presence of NA in filamentous fungi and some mosses, whereas an analogue of NA was inferred in an archaeon. More recently, opine-type metallophores with homology to NA were uncovered in bacteria, especially in human pathogens such as Staphylococcus aureus, Pseudomonas aeruginosa or Yersinia pestis, synthesizing respectively staphylopine, pseudopaline and yersinopine. Here, we review the current state of knowledge regarding the discovery, biosynthesis, function and regulation of these metallophores. We also discuss the genomic environment of the cntL gene, which is homologous to the plant NA synthase (NAS) gene, and plays a central role in the synthesis of NA-like metallophores. This reveals a large diversity of biosynthetic, export and import pathways. Using sequence similarity networks, we uncovered that these metallophores are widespread in numerous bacteria thriving in very different environments, such as those living at the host-pathogen interface, but also in the soil. We additionally established a phylogeny of the NAS/cntL gene and, as a result, we propose that this gene is an ancient gene and NA, or its derivatives, is an ancient metallophore that played a prominent role in metal acquisition or metal resistance. Indeed, our phylogenetic analysis suggests an evolutionary model where the possibility to synthesize this metallophore was present early in the appearance of life, although it was later lost by most living microorganisms, unless facing metal starvation such as at the host-pathogen interface or in some soils. According to our model, NA then re-emerged as a central metabolite for metal homeostasis in fungi, mosses and all known higher plants.