Reactive Peroxynitrite Research Articles

Mitochondrial Hyperactivity and Reactive Oxygen Species Drive Innate Immunity to the Yellow Fever Virus-17D Live-Attenuated Vaccine.

The yellow fever virus 17D (YFV-17D) live attenuated vaccine is considered one of the successful vaccines ever generated associated with high antiviral immunity, yet the signaling mechanisms that drive the response in infected cells are not understood. Here, we provide a molecular understanding of how metabolic stress and innate immune responses are linked to drive type I IFN expression in response to YFV-17D infection. Comparison of YFV-17D replication with its parental virus, YFV-Asibi, and a related dengue virus revealed that IFN expression requires RIG-I-like Receptor signaling through MAVS, as expected. However, YFV-17D uniquely induces mitochondrial respiration and major metabolic perturbations, including hyperactivation of electron transport to fuel ATP synthase. Mitochondrial hyperactivity generates reactive oxygen species (mROS) and peroxynitrite, blocking of which abrogated IFN expression in non-immune cells without reducing YFV-17D replication. Scavenging ROS in YFV-17D-infected human dendritic cells increased cell viability yet globally prevented expression of IFN signaling pathways. Thus, adaptation of YFV-17D for high growth uniquely imparts mitochondrial hyperactivity generating mROS and peroxynitrite as the critical messengers that convert a blunted IFN response into maximal activation of innate immunity essential for vaccine effectiveness.

Perceptions of peroxynitrite reactivity – Then and now

Many chemical and biological reactions involving peroxynitrite3 occur by unusual rate laws that are independent of the identity of the reacting partner. The true nature of these reactions and the identities of actual reactive species have been the subject of considerable debate ever since the notion that peroxynitrite is an important component of oxidative stress was first introduced in the early 1990s. We present herein a succinct historical review of this topic written from the perspective that intermediary inorganic free radicals are the causative agents in these reactions. This viewpoint provides a complete self-consistent rationalization of all verified data from multiple laboratories, whereas other explanations have been unable to do so. Recognition of the radical nature of peroxynitrite decomposition has also allowed a reassessment of the quantitative mechanism of CO2-catalyzed peroxynitrite decomposition. Detailed analyses indicate that the constant for rate-limiting formation of the putative reactive carbon dioxide adduct (ONOOCO2−)3 is actually ∼20% less than previously recognized and CO2 turnover numbers for catalysis (that is, the number of reaction cycles that CO2 undergoes before being removed as bicarbonate) are relatively large and dependent upon the [CO2]/[ONOO−] ratio in the reaction environment.

Reaction of peroxynitrite with thiols, hydrogen sulfide and persulfides

Three decades of research on the biochemistry of peroxynitrite (ONOOH/ONOO−) have established that this stealthy oxidant is formed in biological systems, and that its main targets are carbon dioxide (CO2), metalloproteins and thiols (RSH). Peroxynitrous acid reacts directly with thiols (precisely, with thiolates, RS−), forming sulfenic acids (RSOH). In addition, the free radicals derived from peroxynitrite, mainly carbonate radical anion (CO3•−) and nitrogen dioxide (NO2•) formed from the reaction of peroxynitrite anion with CO2, oxidize thiols to thiyl radicals (RS•). These two pathways are under kinetic competition. The primary products of thiol oxidation can follow different decay routes; sulfenic acids usually react with other thiols forming disulfides, while thiyl radicals can react with oxygen, with other thiols and with other reductants such as ascorbic acid. Peroxynitrite is also able to oxidize hydrogen sulfide (H2S/HS−) and persulfides (RSSH/RSS−). Among the different biological thiols, peroxiredoxins stand out as main peroxynitrite reductases due to their very high rate constants of reaction with peroxynitrite together with their abundance. Rooted in kinetic concepts, evidence is emerging for the role of peroxiredoxins in peroxynitrite detoxification, with potential implications in diseases in which peroxynitrite is involved.

Mitochondrial Ca2+-coupled generation of reactive oxygen species, peroxynitrite formation, and endothelial dysfunction in Cantú syndrome.

Cantú syndrome is a multisystem disorder caused by gain-of-function (GOF) mutations in KCNJ8 and ABCC9, the genes encoding the pore-forming inward rectifier Kir6.1 and regulatory sulfonylurea receptor SUR2B subunits, respectively, of vascular ATP-sensitive K+ (KATP) channels. In this study, we investigated changes in the vascular endothelium in mice in which Cantú syndrome-associated Kcnj8 or Abcc9 mutations were knocked in to the endogenous loci. We found that endothelium-dependent dilation was impaired in small mesenteric arteries from Cantú mice. Loss of endothelium-dependent vasodilation led to increased vasoconstriction in response to intraluminal pressure or treatment with the adrenergic receptor agonist phenylephrine. We also found that either KATP GOF or acute activation of KATP channels with pinacidil increased the amplitude and frequency of wave-like Ca2+ events generated in the endothelium in response to the vasodilator agonist carbachol. Increased cytosolic Ca2+ signaling activity in arterial endothelial cells from Cantú mice was associated with elevated mitochondrial [Ca2+] and enhanced reactive oxygen species (ROS) and peroxynitrite levels. Scavenging intracellular or mitochondrial ROS restored endothelium-dependent vasodilation in the arteries of mice with KATP GOF mutations. We conclude that mitochondrial Ca2+ overload and ROS generation, which subsequently leads to nitric oxide consumption and peroxynitrite formation, cause endothelial dysfunction in mice with Cantú syndrome.

The Ubiquity of the Reaction of the Labile Iron Pool That Attenuates Peroxynitrite-Dependent Oxidation Intracellularly.

Although the labile iron pool (LIP) biochemical identity remains a topic of debate, it serves as a universal homeostatically regulated and essential cellular iron source. The LIP plays crucial cellular roles, being the source of iron that is loaded into nascent apo-iron proteins, a process akin to protein post-translational modification, and implicated in the programmed cell death mechanism known as ferroptosis. The LIP is also recognized for its reactivity with chelators, nitric oxide, and peroxides. Our recent investigations in a macrophage cell line revealed a reaction of the LIP with the oxidant peroxynitrite. In contrast to the LIP's pro-oxidant interaction with hydrogen peroxide, this reaction is rapid and attenuates the peroxynitrite oxidative impact. In this study, we demonstrate the existence and antioxidant characteristic of the LIP and peroxynitrite reaction in various cell types. Beyond its potential role as a ubiquitous complementary or substitute protection system against peroxynitrite for cells, the LIP and peroxynitrite reaction may influence cellular iron homeostasis and ferroptosis by changing the LIP redox state and LIP binding properties and reactivity.

Exploring the novel benefits of leucine: Protecting nitrite-induced liver damage in sub-adult grass carp (Ctenopharyngodon idella) through regulating mitochondria quality control

Leucine is an essential amino acid for fish. The ability of leucine to resist stress in fish has not been reported. Nitrite is a common pollutant in the aquatic environment. Therefore, we investigated the effects of dietary leucine on growth performance and nitrite-induced liver damage, mitochondrial dysfunction, autophagy, and apoptosis for sub-adult grass carp. A total of 450 grass carp (615.91 ± 1.15 g) were selected and randomly placed into 18 net cages. The leucine contents of the six diets were 2.91, 5.90, 8.92, 11.91, 14.93, and 17.92 g/kg, respectively. After a 9-week feeding trial, the nitrite exposure experiment was set up for 96 h. These results indicated that dietary leucine significantly promoted FW, WG, PWG, and SGR of sub-adult grass carp (P < 0.05). Appropriate levels of dietary leucine (11.91–17.92 g/kg) decreased the activities of serum parameters (glucose, cortisol, and methemoglobin contents, glutamic oxaloacetic transaminase, glutamic pyruvic transaminase, and lactate dehydrogenase), the contents of reactive oxygen species (ROS), nitric oxide (NO) and peroxynitrite (ONOO−). In addition, appropriate levels of dietary leucine (11.91–17.92 g/kg) increased the mRNA levels of mitochondrial biogenesis genes (PGC-1α, Nrf1/2, TFAM), fusion-related genes (Opa1, Mfn1/2) (P < 0.05), and decreased the mRNA levels of caspase 3, caspase 8, caspase 9, fission-related gene (Drp1), mitophagy-related genes (Pink1, Parkin) and autophagy-related genes (Beclin1, Ulk1, Atg5, Atg7, Atg12) (P < 0.05). Appropriate levels of dietary leucine (8.92–17.92 g/kg) also increased the protein levels of AMP-activated protein kinase (AMPK), prostacyclin (p62) and decreased the protein levels of protein light chain 3 (LC3), E3 ubiquitin ligase (Parkin), and Cytochrome c (Cytc). Appropriate levels of leucine (8.92–17.92 g/kg) could promote growth performance and alleviate nitrite-induced mitochondrial dysfunction, autophagy, apoptosis for sub-adult grass carp. Based on quadratic regression analysis of PWG and serum GPT activity, dietary leucine requirements of sub-adult grass carp were recommended to be 12.47 g/kg diet and 12.55 g/kg diet, respectively.

Tumor-associated CD8+T cell tolerance induced by erythroid progenitor cells.

CD8+T cell tolerance plays an important role in tumor escape. Recent studies have shown that CD45+ erythroid progenitor cells (CD45+EPCs) generated through splenic extramedullary erythropoiesis suppress tumor immunity. However, the mechanism underlying how CD45+EPCs mediate CD8+T cell tolerance remains incompletely understood and requires further research. In this study, the antigen-processing abilities of CD45+EPCs was verified through both in vitro and in vivo experiments. We have used the method of co-culture in vitro and adoptive transfer experiments in vivo to explore the effects of CD45+EPCs on CD8+T cell tolerance. RNA-sequencing analysis and blocking experiments were used to evaluate the role of ROS in the CD45+EPC mediated tolerance of CD8+T cells. Finally, we incorporated uric acid into the adoptive transfer experiments to rescue the CD45+EPC mediated tumor-promoting effect. We found that CD45+EPCs take up soluble proteins, present antigenic epitopes on their surface, and induce antigen-specific CD8+T cell anergy. In addition, we found that CD45+EPC directly nitrates tyrosine within the TCR/CD8 complex via the production of reactive oxygen species and peroxynitrite, preventing CD8+ T cells from responding to their specific peptide antigens. Furthermore, uric acid treatment effectively abolished the immunosuppressive effects of CD45+EPCs during CD8+T cell adoptive transfer, thereby enhancing the anti-tumor efficacy. These results demonstrated that CD8+T cell tolerance in tumor-bearing mice is induced by CD45+EPCs. The results of this study have direct implications for tumor immunotherapy.

Closing Dichloramine Decomposition Nitrogen and Oxygen Mass Balances: Relative Importance of End-Products from the Reactive Nitrogen Species Pathway.

In drinking water chloramination, monochloramine autodecomposition occurs in the presence of excess free ammonia through dichloramine, the decay of which was implicated in N-nitrosodimethylamine (NDMA) formation by (i) dichloramine hydrolysis to nitroxyl which reacts with itself to nitrous oxide (N2O), (ii) nitroxyl reaction with dissolved oxygen (DO) to peroxynitrite or mono/dichloramine to nitrogen gas (N2), and (iii) peroxynitrite reaction with total dimethylamine (TOTDMA) to NDMA or decomposition to nitrite/nitrate. Here, the yields of nitrogen and oxygen-containing end-products were quantified at pH 9 from NHCl2 decomposition at 200, 400, or 800 μeq Cl2·L-1 with and without 10 μM-N TOTDMA under ambient DO (∼500 μM-O) and, to limit peroxynitrite formation, low DO (≤40 μM-O). Without TOTDMA, the sum of free ammonia, monochloramine, dichloramine, N2, N2O, nitrite, and nitrate indicated nitrogen recoveries ±95% confidence intervals were not significantly different under ambient (90 ± 6%) and low (93 ± 7%) DO. With TOTDMA, nitrogen recoveries were less under ambient (82 ± 5%) than low (97 ± 7%) DO. Oxygen recoveries under ambient DO were 88-97%, and the so-called unidentified product of dichloramine decomposition formed at about three-fold greater concentration under ambient compared to low DO, like NDMA, consistent with a DO limitation. Unidentified product formation stemmed from peroxynitrite decomposition products reacting with mono/dichloramine. For a 2:2:1 nitrogen/oxygen/chlorine atom ratio and its estimated molar absorptivity, unidentified product inclusion with uncertainty may close oxygen recoveries and increase nitrogen recoveries to 98% (ambient DO) and 100% (low DO).

Abstract 3774: MiR-34b promotes cellular senescence and ROS generation in human cervical cancer cells

Abstract Background: Cervical cancer is one of the most common cancers in women worldwide, particularly in low- and middle-income countries. Due to low surveillance and late detection, it is one of the major health issues leading to high mortality rates. MicroRNA-34 family (miR-34a, b, c) is thought to be tumor suppressive in several cancers but the mechanistic basis is not clear. Methods: Stable cell lines were generated with inducible hsa-miR-34b lentiviral vector from Dharmacon and maximal time and dose for induction of miR-34b with doxycycline were determined. Cell viability studies on HeLa, SiHa and C33A were investigated by MTT assay. Acridine orange/Ethidium bromide (AO/EB), senescence associated β-galactosidase (SA- β gal) assays for apoptosis and senescence and assessment of DNA damage (γH2AX) were performed. Total reactive oxygen species (ROS), superoxide, hydroxyl and peroxynitrite and H2O2 radicals were quantitated by DCFDA, DHE, HPF dyes and pHyper-dMito plasmid, respectively. Results: Overexpression of miR-34b reduced cell viability in cervical cancer cell lines except SiHa. Further investigation by AO/EB staining revealed no significant increase in the proportion of apoptotic cells on overexpression of miR-34b. Analysis of SA- β gal on overexpression of miR-34b revealed an increase in the proportion of senescent population in all 3 cell lines. Increased DNA damage is also observed in agreement with an increase in cellular senescence. In addition, an increase in oxidative stress was observed in miR-34b overexpressing cell lines as total ROS was elevated in all 3 cell lines with increased superoxide, hydroxyl and peroxynitrite and H2O2 radicals in HeLa and C33A while SiHa showed increased levels of H2O2 radicals with no significant change in other radicals. Conclusions: Overexpression of miR-34b can promote an increase in cellular senescence and oxidative stress in cervical cancer. The differential action in different cell lines may be due to the difference in expression of miR-34b in these cell lines. Our results highlight the potential of miR-34b to be used for therapeutic intervention in cervical cancer. Citation Format: K J Sindhu, Devarajan Karunagaran. MiR-34b promotes cellular senescence and ROS generation in human cervical cancer cells. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3774.

Ultrasound-Induced Piezocatalysis Triggered NO Generation for Enhanced Hypoxic Tumor Therapy.

Conventional NO gas generation based on l-arginine (l-Arg) is usually dependent on H2O2 and O2, both of which are very limited within the tumor microenvironment, thus greatly limiting l-Arg's therapeutic effect. Herein, a novel nanoplatform for efficiently triggering NO production based on ultrasound-induced piezocatalysis was developed, which was fabricated by coating amphiphilic poly-l-arginine (DSPE-PEG2000-Arg, DPA) on the piezoelectric material of barium titanate (BTO). The resulting BTO@DPA nanoparticles can efficiently generate H2O2, 1O2, and O2 via ultrasound-induced piezocatalysis based on BTO and oxidize the surface arginine to produce NO, which can even further interact with the reactive oxygen species (ROS) to produce more reactive peroxynitrite, thus inducing serious tumor cell apoptosis both in hypoxia and normoxia. After intravenous injection, BTO@DPA accumulated well at the tumor tissue at 4 h postinjection; later, ultrasound irradiation on the tumor not only achieved the best tumor inhibition rate of ∼70% but also completely inhibited tumor metastasis to the lungs via the alleviation of tumor hypoxia. Such a strategy was not dependent on the tumor microenvironment and can be well controlled by ultrasound irradiation, providing a simple and efficient therapy paradigm for hypoxic tumor.

Peroxynitrite Contributes to Behavioral Responses, Increased Trigeminal Excitability, and Changes in Mitochondrial Function in a Preclinical Model of Migraine.

Administration of a nitric oxide (NO) donor triggers migraine attacks, but the mechanisms by which this occurs are unknown. Reactive nitroxidative species, including NO and peroxynitrite (PN), have been implicated in nociceptive sensitization, and neutralizing PN is antinociceptive. We determined whether PN contributes to nociceptive responses in two distinct models of migraine headache. Female and male mice were subjected to 3 consecutive days of restraint stress or to dural stimulation with the proinflammatory cytokine interleukin-6. Following resolution of the initial poststimulus behavioral responses, animals were tested for hyperalgesic priming using a normally non-noxious dose of the NO donor sodium nitroprusside (SNP) or dural pH 7.0, respectively. We measured periorbital von Frey and grimace responses in both models and measured stress-induced changes in 3-nitrotyrosine (3-NT) expression (a marker for PN activity) and trigeminal ganglia (TGs) mitochondrial function. Additionally, we recorded the neuronal activity of TGs in response to the PN generator SIN-1 [5-amino-3-(4-morpholinyl)-1,2,3-oxadiazolium chloride]. We then tested the effects of the PN decomposition catalysts Fe(III)5,10,15,20-tetrakis(N-methylpyridinium-4-yl) porphyrin (FeTMPyP) and FeTPPS [Fe(III)5,10,15,20-tetrakis(4-sulfonatophenyl)porphyrinato chloride], or the PN scavenger MnTBAP [Mn(III)tetrakis(4-benzoic acid)porphyrin] against these behavioral, molecular, and neuronal changes. Neutralizing PN attenuated stress-induced periorbital hypersensitivity and priming to SNP, with no effect on priming to dural pH 7.0. These compounds also prevented stress-induced increases in 3-NT expression in both the TGs and dura mater, and attenuated TG neuronal hyperexcitability caused by SIN-1. Surprisingly, FeTMPyP attenuated changes in TG mitochondrial function caused by SNP in stressed males only. Together, these data strongly implicate PN in migraine mechanisms and highlight the therapeutic potential of targeting PN.SIGNIFICANCE STATEMENT Among the most reliable experimental triggers of migraine are nitric oxide donors. The mechanisms by which nitric oxide triggers attacks are unclear but may be because of reactive nitroxidative species such as peroxynitrite. Using mouse models of migraine headache, we show that peroxynitrite-modulating compounds attenuate behavioral, neuronal, and molecular changes caused by repeated stress and nitric oxide donors (two of the most common triggers of migraine in humans). Additionally, our results show a sex-specific regulation of mitochondrial function by peroxynitrite following stress, providing novel insight into the ways in which peroxynitrite may contribute to migraine-related mechanisms. Critically, our data underscore the potential in targeting peroxynitrite formation as a novel therapeutic for the treatment of migraine headache.

An Ultrasound-Triggered Nanoplatform for Synergistic Sonodynamic-Nitric Oxide Therapy.

Ultrasound (US)-triggered sonodynamic therapy (SDT) has aroused intensive interest as a powerful alternative for cancer treatment in recent years due to its non-invasiveness and deep tissue penetration. However, the therapeutic effect of SDT alone is still limited by intrinsic hypoxia in solid tumors. Combined synergistic therapy strategies are highly desired for improving therapeutic efficiency. Herein, a rationally designed intelligent theranostic nanoplatform is developed for the enhancement of cancer treatment through synergistic SDT and nitric oxide (NO) therapy. This US-triggered nanoplatform is fabricated by integrating a sonosensitizer Rose Bengal (RB) and a NO donor (SNO) into manganese-doped hollow mesoporous silica nanoparticles (MH-SNO@RB). Impressively, the acidic and reducing tumor microenvironment accelerates the sustainable release of Mn ions from the framework, which facilitates the MH-SNO@RB to be used as a contrast agent for magnetic resonance imaging. More importantly, the reactive oxygen species (ROS) generated by RB and NO molecules released from SNO, which are simultaneously triggered by US, can react with each other to yield highly reactive peroxynitrite (ONOO-) ions for effective tumor inhibition both in vitro and in vivo. Furthermore, the nanoplatform demonstrates good hemocompatibility and histocompatibility. This study opens a new strategy for the full utilization of US and intelligent design avenues for high-performance cancer treatment.

Redox profile and mediators of the unfolded protein response (UPR) in the placenta of rats during pregnancy.

Proliferation, differentiation, migration and apoptosis of trophoblastic cells are influenced by hypoxia, as well as adequate modulation of oxidative stress and the unfolded protein response (UPR) pathway. We aimed to evaluate the expression profile of redox and UPR mediators in the placenta of rats throughout pregnancy. Placental expression of hypoxia-inducible factor 1α (HIF1α), 8-Hydroxy-2'-deoxyguanosine (8-OHdG), superoxide dismutase 1 (SOD1), glutathione peroxidase (GPX), catalase (Cat), activating transcription factor 6 (ATF6), protein kinase RNA-like endoplasmic reticulum kinase (PERK), 78 kD glucose-regulated protein (GRP78) and C/EBP-homologous protein (CHOP), as well as reactive oxygen species (ROS) and peroxynitrite production, were evaluated in Wistar rats on the 10th, 12th, 14th, 16th and 18th day of pregnancy (DP). Increased immunostaining of HIF1α was observed on the 16th and 18th DP, while 8-OHdG and ROS production were greater on the 14th DP. SOD1 and Cat had increased immunostaining on the 14th and 18th DP, while staining of GPX1/2, GRP78 and CHOP was greater on the 18th DP. With regard to gene expression, Hif1α and Sod1 showed increased mRNA expression on the 12th and 16th DP, while Gpx1 had increased expression on the 10th and 16th DP. Cat, Perk and Grp78 gene expression was greater on the 14th DP, unlike Atf6, which showed greater expression on the 12th DP. In contrast, Chop maintained increased expression from the 12th to the 18th DP. The placental expression of redox and UPR mediators in rats is influenced by gestational age, with greater expression in periods of greater HIF1α and 8-OHdG expression and at the end of the pregnancy. This study provides data on the physiological modulation of redox and UPR mediators during placental development in rats.

Bioinspired nanovehicle of furoxans-oxaliplatin improves tumoral distribution for chemo-radiotherapy.

The spatiotemporal distribution of therapeutic agents in tumors remains an essential challenge of radiation-mediated therapy. Herein, we rationally designed a macrophage microvesicle-inspired nanovehicle of nitric oxide donor-oxaliplatin (FO) conjugate (M-PFO), aiming to promote intratumor permeation and distribution profiles for chemo-radiotherapy. FO was responsively released from M-PFO in intracellular acidic environments, and then be activated by glutathione (GSH) into active oxaliplatin and NO molecules in a programmed manner. M-PFO exhibited notable accumulation, permeation and cancer cell accessibility in tumor tissues. Upon radiation, the reactive peroxynitrite species (ONOO-) were largely produced, which could diffuse into regions over 400μm away from the tumor vessels and be detectable after 24h of radiation, thereby exhibiting superior efficacy in improving the spatiotemporal distribution in tumors versus common reactive oxygen species (ROS). Moreover, M-PFO mediated chemo-radiotherapy caused notable inhibition of tumor growth, with an 89.45% inhibition in HT-29 tumor models and a 92.69% suppression in CT-26 tumor models. Therefore, this bioinspired design provides an encouraging platform to improve intratumor spatiotemporal distribution to synergize chemo-radiotherapy.

Kinetics-Based Quantification of Peroxynitrite Using the Oxidative Decarbonylation of Isatin.

Peroxynitrite and its radical decomposition products are highly reactive nitrogen and oxygen species that can influence the balance between health and disease in multiple organ systems. Despite vigorous research activity, real-time quantitative monitoring of peroxynitrite generated by donor compounds remains challenging. Here, we report a kinetics-based fluorescence method for quantitative tracking of peroxynitrite generation using the oxidative decarbonylation of isatin to form anthranilic acid as a fluorescent probe. This method relies on knowledge of the rate of the reaction of peroxynitrite with the probe, which we measure using stopped-flow fluorescence techniques. To the best of our knowledge, this is the first optical method capable of providing real-time quantitative measures of peroxynitrite concentrations generated from donor compounds, as demonstrated herein for SIN-1 and Angeli's salt.

Effect of water diuresis with hydrogen saturation on the course of acute kidney damage during the separation of oxidation and phosphorylation

Molecular hydrogen has the ability to penetrate cells, easily reach mitochondria, overcome body barriers, penetrate areas of ischemia, edema and inflammation, improve energy supply by supplying additional electrons and have antioxidant and anti-inflammatory effects by neutralizing highly reactive hydroxyl radical and peroxynitrite. In this experiment, we included 60 nonlinear male rats weighing 0.16-0.18 kg and investigated the effect of a negative redox potential solution -297.3±5.27 mV with a molecular hydrogen saturation of 1.2 ppm on the functional-biochemical processes of the kidneys in tissue hypoxia in moderately resistant rats during the separation of oxidation and phosphorylation with the introduction of 2,4-dinitrophenol at a dose of 3 mg/kg. All studies were performed on moderately stable rats. Experimental, functional, biochemical, enzyme-linked immunosorbent, physicochemical, histoenzymochemical, and statistical research methods were used. Under conditions of renal hypoxia in the separation of oxidation and phosphorylation, the use of a solution of negative redox reabsorption of sodium ions in the distal nephron reduces the manifestations of tubular proteinuria, increases the activity of succinate dehydrogenase in the proximal nephron and reduces the redox potential of urine to negative values. Negative redox potential solution with molecular hydrogen saturation has a protective effect on the kidneys and reduces elevated levels of proinflammatory cytokines of tumor necrosis factor-α, interleukin-1-β, and interleukin-6 in blood plasma, and causes oxidative modification of proteins in the renal cortex for their hypoxia in the separation of oxidation and phosphorylation.

Peroxynitrite Reactivity with Capsaicin: A Potential for Capsaicin-Based Sensing Devices

Peroxynitrite and other reactive oxygen species (ROS) have been linked to illnesses caused by oxidative stress, such as atherosclerosis. Accurate detection of these species in biological systems is crucial not only for understanding the etiology and course of the disease but also for creating and evaluating viable therapies. In the last 30 years, there has been an exponential increase in research into capsaicin's biological relevance. Capsaicin has analgesic, antioxidant, anti-inflammatory, anti-cancer, and anti-obesity properties. Most of these investigations have focused on the analgesic, antioxidant, and anticancer properties of this chemical compound throughout the last three decades. Capsaicin has been shown to increase the production of peroxynitrite by boosting the formation of superoxide anions in combination with nitric oxide.Preliminary UV-Vis results suggested a potential interaction at micromolar levels between capsaicin and peroxynitrite. A hyperchromic shift has been shown at a wavelength of ~ 300 nm, indicating an interaction between capsaicin and peroxynitrite, which resulted in a 2x increase in absorbance. The interaction of capsaicin and peroxynitrite was further studied using cyclic voltammetry and differential pulse voltammetry.

Bottom-up Design of Organic Selenide Interfaces for Sensitive Electrocatalytic Detection of Peroxynitrite: A Fundamental Investigation and Application

Peroxynitrite (PON) is a potent oxidative stress species that has been linked with both oxidation and nitration reactions in biological systems. It emerged as a major cytotoxic agent that is implicated in a host of pathophysiological conditions. Reports emphasized the deleterious physiological reactivity of peroxynitrite with different cellular targets including DNA, proteins, and lipids in cell membranes. This oxidant has also been linked to cytoprotective roles under certain conditions. The balance between the deleterious reactivity and its potential cytoprotective roles of peroxynitrite depends on the dynamic concentration of this species. However, accurate determination of peroxynitrite concentration is inherently difficult particularly in biological systems. Various methods for peroxynitrite determination have been reported including indirect spectroscopic assays and, recently, direct electrochemical methods. While the development of electrochemical sensors for PON is currently a very active field, viable electrochemical probes for PON detection and quantification are still relatively illusive.In this work, we prepared and characterized a series of functional thin film materials based on organic diphenyl selenides on graphite electrodes and used these interfaces to compare and contrast their performance in terms of electrochemical determination of peroxynitrite.We will describe the preparation and grafting of the catalytic material based on the electrodeposition of various organic aminodiphenyl selenides on graphite electrodes. Several physicochemical methods including Scanning Electron Microscopy (SEM), Energy Dispersive X-ray spectroscopy (EDX) and X-ray Photoelectron Spectroscopy (XPS) were used to characterize the resulting modified interfaces. We will describe the performance of resulting selenide thin films as peroxynitrite sensing interfaces using voltammetry and amperometry. The grafted thin film materials show a significant enhancement in peroxynitrite oxidative current compared to controls under the same conditions. For all selenides tested, we show that the enhancement in peroxynitrite signal is the result of an electrocatalytic mechanism where the grafted aniline selenide-based material at the oxidized state mediates the electrocatalytic oxidation of peroxynitrite. We will compare and contrast the performance of the various selenide systems and explore if the modulation of the electronic properties of the selenium catalytic center results in proportional changes in PON catalytic efficiency. Figure 1

Maternal hypothyroidism causes oxidative stress and endoplasmic reticulum stress in the maternal-fetal interface of rats.

Maternal hypothyroidism is associated with pre-eclampsia and intrauterine growth restriction, gestational diseases involving oxidative stress (OS) and endoplasmic reticulum stress (ERS) in the placenta. However, it is not known whether hypothyroidism also causes OS and ERS at the maternal-fetal interface. The aim was to evaluate the fetal-placental development and the expression of mediators of OS and of the unfolded protein response (UPR) in the maternal-fetal interface of hypothyroid rats. Hypothyroidism was induced in Wistar rats with propylthiouracil and the fetal-placental development and placental and decidual expression of antioxidant, hypoxia, and UPR mediators were analyzed at 14 and 18 days of gestation (DG), as well the expression of 8-OHdG and MDA, and reactive oxygen species (ROS) and peroxynitrite levels. Hypothyroidism reduced fetal weight at 14 and 18 DG, in addition to increasing the percentage of fetal death and reducing the weight of the uteroplacental unit at 18 DG. At 14 DG, there was greater decidual and/or placental immunostaining of Hif1α, 8-OHdG, MDA, SOD1, GPx1/2, Grp78 and CHOP in hypothyroid rats, while there was a reduction in placental and/or decidual gene expression of Sod1, Gpx1, Atf6, Perk, Ho1, Xbp1, Grp78 and Chop in the same gestational period. At 18 DG, hypothyroidism increased the placental ROS levels and the decidual and/or placental immunostaining of HIF1α, 8-OHdG, MDA, ATF4, GRP78 and CHOP, while it reduced the immunostaining and enzymatic activity of SOD1, CAT, GST. Hypothyroidism increased the placental mRNA expression of Hifα, Nrf2, Sod2, Gpx1, Cat, Perk, Atf6 and Chop at 18 DG, while decreasing the decidual expression of Sod2, Cat and Atf6. These findings demonstrated that fetal-placental restriction in female rats with hypothyroidism is associated with hypoxia and dysregulation in placental and decidual expression of UPR mediators and antioxidant enzymes, and activation of oxidative stress and endoplasmic reticulum stress at the maternal-fetal interface.

Conventional drug acts as a "rifle gun" while hydrogen as a "machine gun".

Most of the drugs used in modern medical treatments are symptomatic treatments and are far from being a cure for the diseases. The adverse effects are unavoidable in the drugs in modern medical treatments. Molecular hydrogen (H2) has a remarkable therapeutic effect on various diseases, and many clinical studies have reported that H2 has no adverse effects. Therefore, H2 is a novel medical gas that is outside the concept of modern medical treatment. H2, unlike drugs, works on the root of many diseases by scavenging the two kinds of strong reactive oxygen species, hydroxyl radical (·OH) and peroxynitrite (ONOO-). Since the H2 alleviates the root of diseases and can treat many diseases at the same time, the medical application of H2 may be called “machine gun therapy.” In this review, we demonstrated that the root of many diseases is based on ·OH-induced oxidative stress in the mitochondria, and at the same time, the root of chronic inflammation is also attributed to ·OH.