Inducible Isoform Research Articles

Anticompulsive-like effect of nitric oxide synthase inhibitors in marble-burying test

Nitric oxide synthase (NOS) inhibitors decrease marble burying behavior (MBB), and the effect of several compounds that also attenuate MBB (such as classical antidepressants) engages the nitrergic system. In the present study, we tested the effect of the NOS inhibitor aminoguanidine (AMG) in attenuating MBB. For comparative reasons, we also tested the effect of selective inhibitors of neuronal (NOS1) and inducible (NOS2) isoforms NPA and 1400W, respectively. Our results indicate that AMG and NPA, but not 1400W, reduced the number of buried marbles in the marble burying test (MBT), which is considered an anticompulsive-like effect. No effect of AMG in the anxiety- or locomotor-related parameters of the elevated plus maze was observed. Taken together, our data is consistent with the current literature that suggests that nitric oxide inhibitors, putatively acting through the neuronal isoform of the synthesis enzyme (NOS1), exhibit anticompulsive-like properties.

Naturally Derived Heme-Oxygenase 1 Inducers and Their Therapeutic Application to Immune-Mediated Diseases.

Heme oxygenase (HO) is the primary antioxidant enzyme involved in heme group degradation. A variety of stimuli triggers the expression of the inducible HO-1 isoform, which is modulated by its substrate and cellular stressors. A major anti-inflammatory role has been assigned to the HO-1 activity. Therefore, in recent years HO-1 induction has been employed as an approach to treating several disorders displaying some immune alterations components, such as exacerbated inflammation or self-reactivity. Many natural compounds have shown to be effective inductors of HO-1 without cytotoxic effects; among them, most are chemicals present in plants used as food, flavoring, and medicine. Here we discuss some naturally derived compounds involved in HO-1 induction, their impact in the immune response modulation, and the beneficial effect in diverse autoimmune disorders. We conclude that the use of some compounds from natural sources able to induce HO-1 is an attractive lifestyle toward promoting human health. This review opens a new outlook on the investigation of naturally derived HO-1 inducers, mainly concerning autoimmunity.

ROLE OF THE REACTIVE OXYGEN AND NITROGEN SPECIES IN THE DEVELOPMENT OF FIBROSIS IN THE TESTES OF RATS WITH PROLONGED CENTRAL DEPRIVATION OF TESTOSTERONE SYNTHESIS

Prostate cancer is the second most common diagnosis in oncology and ranks the fifth among the causes of mortality in men around the world. 1,276,106 cases of newly diagnosed prostate cancer were recorded in 2018. Androgens play a large role in the development of prostate cancer. Elimination of androgens and blockade of their synthesis are key pathogenetic steps in the treatment of prostate cancer. Metabolic and morphological changes in the testes under prolonged central deprivation of testosterone synthesis are currently not well understood. The aim of this study was to establish the role of reactive oxygen and nitrogen species in the development of morphological changes in the testes of rats under prolonged central deprivation of testosterone synthesis. Materials and methods. The experiments were conducted on 20 sexually mature male Wistar rats. Animals were divided into 4 groups of 5 animals in each. The first group (control) received a subcutaneous injection of 0.9% sodium chloride for 180 days. The second group received a subcutaneous injection of diphereline (triptoreline) in a dose of 0.3 mg/kg of active agent for 30 days in order to simulate the central deprivation of testosterone synthesis. In the third group, diphereline was administered in a dose of 0.3 mg/kg of the active agent for 90 days. The fourth group received a subcutaneous injection of diphereline in a dose of 0.3 mg/kg of the active agent for 180 days. Small pieces of testes were fixed and enclosed in paraffin blocks; then 4-μm thick sections were made and stained with hematoxylin and eosin. Histological preparations were studied using an optical microscope with a digital microphotographic nozzle Olympus C 3040-ADU with programs adapted for these studies. The total activity of NO synthases (gNOS), the activity of the inducible isoform of NO synthase (iNOS) and constitutive isoforms (cNOS), as well as the production of superoxide anion radical (O2•-) were determined in 10% homogenate of testes. Results. Long-term central deprivation of testosterone synthesis leads to an increase in the interstitial space volume with the development of fibrotic changes in the testes on the 180th day of the experiment. The wall of seminiferous tubules was compacted, swollen, there were a large number of parietal macrophages from the outside compared to previous periods of the experiment. In the structure of some convoluted seminiferous tubules, first there was discompletion and disorientation, and then desquamation of spermatids. The number of spermatogonia type A and B decreased. Hypochromia and pycnosis were noted in the nuclei. The activities of gNOS and iNOS increased until the 90th day and decreased by 180th when compared with 90th day, remaining higher than the activities of the control group. Activity of cNOS was reduced in all experimental groups. O2•- production increased in all experimental groups. Conclusion: an increase in the production of nitric oxide by the inducible isoform of NO synthase leads to destructive changes in the testes of rats with the subsequent development of fibrotic changes on the 180th day of central deprivation of testosterone synthesis by enhancing the production of superoxide anion radical.

Advancing physiological maturation in human induced pluripotent stem cell-derived cardiac muscle by gene editing an inducible adult troponin isoform switch.

Advancing maturation of stem cell-derived cardiac muscle represents a major barrier to progress in cardiac regenerative medicine. Cardiac muscle maturation involves a myriad of gene, protein, and cell-based transitions, spanning across all aspects of cardiac muscle form and function. We focused here on a key developmentally controlled transition in the cardiac sarcomere, the functional unit of the heart. Using a gene-editing platform, human induced pluripotent stem cell (hiPSCs) were engineered with a drug-inducible expression cassette driving the adult cardiac troponin I (cTnI) regulatory isoform, a transition shown to be a rate-limiting step in advancing sarcomeric maturation of hiPSC cardiac muscle (hiPSC-CM) toward the adult state. Findings show that induction of the adult cTnI isoform resulted in the physiological acquisition of adult-like cardiac contractile function in hiPSC-CMs in vitro. Specifically, cTnI induction accelerated relaxation kinetics at baseline conditions, a result independent of alterations in the kinetics of the intracellular Ca2+ transient. In comparison, isogenic unedited hiPSC-CMs had no cTnI induction and no change in relaxation function. Temporal control of adult cTnI isoform induction did not alter other developmentally regulated sarcomere transitions, including myosin heavy chain isoform expression, nor did it affect expression of SERCA2a or phospholamban. Taken together, precision genetic targeting of sarcomere maturation via inducible TnI isoform switching enables physiologically relevant adult myocardium-like contractile adaptations that are essential for beat-to-beat modulation of adult human heart performance. These findings have relevance to hiPSC-CM structure-function and drug-discovery studies in vitro, as well as for potential future clinical applications of physiologically optimized hiPSC-CM in cardiac regeneration/repair.

Association of plasma cyclooxygenase-2 levels and genetic polymorphisms with salt sensitivity, blood pressure changes and hypertension incidence in Chinese adults.

Cyclooxygenase (COX)-2, an inducible isoform of the major rate-limiting enzymes that regulate the production of prostaglandins is associated with injury, inflammation and proliferation. We sought to examine whether plasma COX-2 levels and its genetic variants is associated with salt sensitivity, BP changes and/or hypertension in humans. Eighty participants (aged 18-65 years) were maintained sequentially either on a usual diet for 3 days, a low-salt diet (3.0 g) for 7 days, and a high-salt diet (18.0 g) for an additional 7 days. In addition, we studied participants of the original Baoji Salt-Sensitive Study, recruited from 124 families from seven Chinese villages in 2004 who received the same salt intake intervention, and evaluated them for the development of hypertension. Plasma COX-2 levels were significantly decreased with reduction of salt intake from the usual to a low-salt diet and decreased further when converting from the low-salt to the high-salt diet. SNPs rs12042763 in the COX-2 gene was significantly associated with SBP responses to both low-salt and high-salt diet. SNPs rs689466 and rs12042763 were significantly associated with longitudinal changes in BPs. In addition, several COX-2 SNPs were significantly associated with incident hypertension over an 8-year follow-up. Gene-based analyses also supported the overall association of COX-2 with longitudinal changes in SBP and hypertension incidence. This study shows that dietary salt intake affects plasma COX-2 levels and that COX-2 may play a role in salt sensitivity, BP progression and development of hypertension in the Chinese populations studied.

Ameliorating Activity of Ishige okamurae on the Amyloid Beta-Induced Cognitive Deficits and Neurotoxicity through Regulating ERK, p38 MAPK, and JNK Signaling in Alzheimer's Disease-Like Mice Model.

Alzheimer's disease (AD) is associated with amyloid beta peptide (Aβ25-35 ) accumulation in brains, which induces neurotoxicity and cognitive impairment. The effects of Ishige okamurae, an edible brown algae, on Aβ25-35 -induced cognitive impairment and neuronal toxicity is investigated. The aim of this study is to determine the molecular mechanisms responsible for I. okamurae extracts (IOE) mediating anti-AD effects. Oral administration of IOE significantly attenuated Aβ25-35 -induced cognitive deficits, as estimated by Y-maze and Morris water maze tests. IOE also attenuated the Aβ25-35 -induced cellular apoptosis and expression of inducible isoforms of nitric oxide synthases (iNOS) and cyclooxygenase-2 (COX-2) in mouse brains and PC12 cells. In addition, Aβ25-35 -induced phosphorylation of ERK, p38 MAPK, and JNK in mouse brains and PC12 cells is significantly abolished by administration of IOE. In PC12 cells, pretreatment of signal inhibitors (PD98059 (MEK inhibitor), SB203580 (p38 MAPK inhibitor), and SP600125 (JNK inhibitor)) recovers Aβ25-35 -mediated cellular dysregulations to the same extent as does IOE pretreatment. Taken together, the data suggest that Aβ25-35 -induced AD progress may be attenuated by administration of IOE through prevention of Aβ25-35 -induced phosphorylation of ERK, p38 MAPK, and JNK.

Identification of Alternative Mitochondrial Electron Transport Pathway Components in Chickpea Indicates a Differential Response to Salinity Stress between Cultivars.

All plants contain an alternative electron transport pathway (AP) in their mitochondria, consisting of the alternative oxidase (AOX) and type 2 NAD(P)H dehydrogenase (ND) families, that are thought to play a role in controlling oxidative stress responses at the cellular level. These alternative electron transport components have been extensively studied in plants like Arabidopsis and stress inducible isoforms identified, but we know very little about them in the important crop plant chickpea. Here we identify AP components in chickpea (Cicer arietinum) and explore their response to stress at the transcript level. Based on sequence similarity with the functionally characterized proteins of Arabidopsis thaliana, five putative internal (matrix)-facing NAD(P)H dehydrogenases (CaNDA1-4 and CaNDC1) and four putative external (inter-membrane space)-facing NAD(P)H dehydrogenases (CaNDB1-4) were identified in chickpea. The corresponding activities were demonstrated for the first time in purified mitochondria of chickpea leaves and roots. Oxidation of matrix NADH generated from malate or glycine in the presence of the Complex I inhibitor rotenone was high compared to other plant species, as was oxidation of exogenous NAD(P)H. In leaf mitochondria, external NADH oxidation was stimulated by exogenous calcium and external NADPH oxidation was essentially calcium dependent. However, in roots these activities were low and largely calcium independent. A salinity experiment with six chickpea cultivars was used to identify salt-responsive alternative oxidase and NAD(P)H dehydrogenase gene transcripts in leaves from a three-point time series. An analysis of the Na:K ratio and Na content separated these cultivars into high and low Na accumulators. In the high Na accumulators, there was a significant up-regulation of CaAOX1, CaNDB2, CaNDB4, CaNDA3 and CaNDC1 in leaf tissue under long term stress, suggesting the formation of a stress-modified form of the mitochondrial electron transport chain (mETC) in leaves of these cultivars. In particular, stress-induced expression of the CaNDB2 gene showed a striking positive correlation with that of CaAOX1 across all genotypes and time points. The coordinated salinity-induced up-regulation of CaAOX1 and CaNDB2 suggests that the mitochondrial alternative pathway of respiration is an important facet of the stress response in chickpea, in high Na accumulators in particular, despite high capacities for both of these activities in leaf mitochondria of non-stressed chickpeas.

A possible role for inducible arginase isoform (AI) in the pathogenesis of chronic venous leg ulcer.

Chronic venous ulcer (CVU) is a major cause of chronic wounds of lower extremities and presents a significant financial and resource burden to health care systems worldwide. Defects in the vasculature, matrix deposition, and re-epithelialization are the main histopathological changes believed to impede healing. Supplementation of the amino acid arginine that plays a crucial role in the interactions that occur during inflammation and wound healing was proven clinically to improve acute wound healing probably through enhancing activity of inducible arginase (AI) locally in the wounds. However, the possible mechanism of arginine action and the potential beneficial effects of AI/arginine in human chronic wounds remain unclear. In the present study, using biopsies, taken under local anesthesia, from adult patients (n = 12, mean age 55 years old) with CVUs in lower extremities, we investigated the correlation between AI distribution in CVUs and the histopathological changes, mainly proliferative and vascular changes. Our results show a distinct spatial distribution of AI along the ulcer in the epidermis and in the dermis with the highest level of expression being at the ulcer edge and the least expression towards the ulcer base. The AI cellular immunoreactivity, enzymatic activity, and protein levels were significantly increased towards the ulcer edge. Interestingly, a similar pattern of expression was encountered in the proliferative and the vascular changes with strong correlations between AI and the proliferative activity and vascular changes. Furthermore, AI cellular distribution was associated with increased proliferative activity, inflammation, and vascular changes. Our findings of differential expression of AI along the CVU base, edge, and nearby surrounding skin and its associations with increased proliferative activity and vascular changes provide further support to the AI implication in CVU pathogenesis. The presence of high levels of AI in the epidermis of chronic wounds may serve as a molecular marker of impaired healing and may provide future targets for therapeutic intervention.

The role of gas mediators of nitrogen (II) oxide and hydrogen sulfide in the development of pathochemical changes in the mucous membrane of rats at water-immobilization and adrenaline-induced stress modeling

Acute and prolonged psycho-emotional overstrain, i.e. stress, are the most frequent factors of ulcer formation in the digestive system. Therefore, the study of molecular mechanisms of stress impact is one of the most promising directions of modern experimental gastroenterology. However, the features of its molecular-biochemical action on the metabolic processes in the digestive system remain insufficiently studied. In this regard, we performed a comparative analysis of changes in indicators of systems of gas mediators of nitrogen (II) oxide and hydrogen sulfide synthesis at water-immobilization and adrenaline-induced stress modeling in experiments on white non-linear rats. Water-immobilization stress (WIS) was modelled by immobilizing animals in a plastic container, and adrenaline-induced stress (AIS) was modelled by injecting adrenaline at a dose of 2 mg/kg intraperitoneally. Modelling WIS caused formation of erosion and spot hemorrhage, located mainly along the folds of the fundus of the stomach. In this case, more noticeable changes were observed in the 5-hour WSI model. Injecting adrenaline at AIS model caused development of structural-hemorrhagic damage in the pyloric part and body of the stomach. The biochemical response to stress is complex, and the release of catecholamines is not the only case of stress. The synthesis of hormones such as glucagon, somatotropin and renin is activated. However, the most important role is played by cortisol, which level of growth in blood is measured to assess the degree of stress development. In our studies, changes in cortisol level in blood under different types of stress modeling (WIS and AIS) had their own peculiarities: at WIS conditions cortisol concentration increased sharply and remained high for 5 hours, while adrenaline did not cause the growth of this “stress hormone”. In our studies, in both models of stress-induced ulcerogenesis there were significant changes to the content of H2S and NO, that confirms the significant role of these substances in development and progression of ulcerogenesis in the digestive system. Thus, H2S concentration decreased at WIS and AIS. There is a significant increase in nitrogen oxide production in both WIS with different duration of action and AIS, which is caused by multiple activation of the inducible isoform of NO-synthase. Therefore, in experimental stress-induced ulcerogenesis, the metabolism of L-arginine in the mucous membrane of stomach is equally shifted towards the formation of NO, that under conditions of strengthening of free radical processes serves as a prerequisite for activation of oxidative-nitric processes and leads to the formation of structural-hemorrhagic damage to the surface of the mucous membrane of stomach. Our studies also show that ulcerative damage to the mucous membrane of stomach in all the types of studied stress was accompanied by an increase in myeloperoxidase activity, indicating an increase in permeability of hemocapillaries due to the development of the inflammatory process.

Stress nitrosant et pathologies

Nitric oxide (NO.) is an important intracellular messenger produced by NO-synthases (NOS); there are three isoforms of NOS: neuronal, endothelial and inducible. Many physiological and pathological functions of NO. have been reported. Depending on its concentrations and its flux, present in a cell, two types of effects can result. Direct effects in one hand, resulting from its direct interaction with the metallic atoms of metalloproteins or with free radicals, leading to nitrosylation reactions, hence its physiological effects. Indirect effects on the other hand, due to the reactive nitrogen species (RNS). The flow of NO. formed, via the inducible isoform, reacts with oxygen (O2) or the superoxide anion (O2.-) producing respectively diazotized trioxide (N2O3) and peroxynitrite (ONOO-) responsible for the reactions of nitrosations and nitrations which can cause oxidative and nitrosating stress. This leads to severe damage to the majority of biological molecules (proteins, lipids, DNA), thus involving NO. in several pathologies (inflammation, diabetes, high blood pressure, cancers, etc.).

Heat stress inducible cytoplasmic isoform of ClpB1 from Z. nummularia exhibits enhanced thermotolerance in transgenic tobacco.

Previously, we isolated CDS of Ziziphus nummularia isoform ZnJClpB1-C from heat stress-tolerant genotype Jaisalmer. To further functionally validate ZnJClpB1-C assumed function in tobacco and to generate novel germplasm for heat stress tolerance, this gene was transformed in theNicotiana tabacum. ClpB proteins are the major key player required for basal and induced heat stress tolerance in plant cells under heat stress. In Ziziphus nummularia ClpB1-C transcript from genotype Jaisalmer was highly upregulated under heat stress conditions, as reported earlier. Nine transgenic lines (T1) from three transgenic tobacco events with single-copy integration (T0 stage) were taken for heat stress analysis at seedling stage. Mature tobacco transgenic plants did not show any deformity as compared to wild plants when grown under normal conditions. Overexpression of ZnJClpB1-C in tobacco significantly increased the tolerance to heat stress. Under heat stress conditions (42°C), T1 transgenic tobacco seedlings showed higher photosynthetic rate, relative water content, membrane stability index and lower levels of MDA, compared to the wild type untransformed plants. The qRT-PCR analysis revealed different level of transgene expression (1.08 to 3.89 folds) in 9 T1 transgenic lines. In vitro roles of ZnJClpB1-C regulating thermotolerance is not reported so far. These results demonstrated the positive roles of ZnJClpB1-C in enhancing thermotolerance and its use as a genomic resource in the near future for developing heat stress-tolerant germplasm.

Effects of selective inhibition of nNOS and iNOS on neuropathic pain in rats

Various animal models have been employed to understand the pathogenic mechanism of neuropathic pain. Nitric oxide (NO) is an important molecule in nociceptive transmission and is involved in neuropathic pain. However, its mechanistic actions remain unclear. The aim of this study was to better understand the involvement of neuronal and inducible isoforms of nitric oxide synthase (nNOS and iNOS) in neuropathic pain induced by chronic constriction injury (CCI) of the sciatic nerve in rats. We evaluated pain sensitivity (mechanical withdrawal thresholds using Randall and Selitto, and von Frey tests, and thermal withdrawal thresholds using Hargreaves test) prior to CCI surgery, 14 days post CCI and after intrathecal injections of selective nNOS or iNOS inhibitors. We also evaluated the distribution of NOS isozymes in the spinal cord and dorsal root ganglia (DRG) by immunohistochemistry, synthesis of iNOS and nNOS by Western blot, and NO production using fluorescent probe DAF-2 DA (DA). Our results showed higher number of nNOS and iNOS-positive neurons in the spinal cord and DRG of CCI compared to sham rats, and their reduction in CCI rats after treatment with selective inhibitors compared to non-treated groups. Western blot results also indicated reduced expression of nNOS and iNOS after treatment with selective inhibitors. Furthermore, both inhibitors reduced CCI-evoked mechanical and thermal withdrawal thresholds but only nNOS inhibitor was able to efficiently lower mechanical withdrawal thresholds using von Frey test. In addition, we observed higher NO production in the spinal cord and DRG of injured rats compared to control group. Our study innovatively shows that nNOS may strongly modulate nociceptive transmission in rats with neuropathic pain, while iNOS may partially participate in the development of nociceptive responses. Thus, drugs targeting nNOS for neuropathic pain may represent a potential therapeutic strategy.

INFLUENCE OF NANOSIZED SILICA OXIDE SUSPENSION ON NITRIC OXIDE PRODUCTION IN RATS TESTES DURING CHRONIC NITRATE-FLUORIDE INTOXICATION

In the Poltava region of Ukraine there is a high possibility of combined excessive intake of nitrates and fluorides, since the waters of the Buchaksʹkii aquifer are rich in fluorine ions, moreover, the Poltava region is a region with a developed agriculture.
 The purpose of this work is to determine the effect of nanosized silicon oxide suspension on the changes in the activity of nitric oxide cycle components, components, and, namely the total activity of NO-synthases (NOS), the activity of constitutive forms of NOS (cNOS), inducible form of NOS (iNOS), nitrate reductase, nitrite reductase, nitrite reductase, nitrite reductase in the testes of rats under the conditions of chronic combined nitrate-fluorodide intoxication.
 Materials and methods. The study was conducted on 15 mature male Wistar rats weighing 200-253 g. The animals were randomly divided into 3 groups of 5 animals in each. The first group received daily saline solution through a gastric tube. The second group (chronic combined intoxication group) received sodium nitrate and fluoride in a dosage of 500 mg / kg of sodium nitrate and 10 mg / kg of sodium fluoride. The third group against the background of chronic combined intoxication modelling additionally received a suspension of nanosized silicon oxide is a dosage of 100 mg / kg of active substance.
 Results. Chronic combined intoxication increases total NOS activity by 65.9% compared to the control group. The increase in NO production by NOS is the result of a 4-fold increase in iNOS activity, since the activity of cNOS under these conditions does not change significantly. Nitrite reductase-dependent NO production increases by 66.7%, nitrate reductase activity increases by 77.8%. Nitrite content in the testes homogenate grows in 2.17 times. Hydrolytic cleavage of L-arginine by arginase increases in 2.88 times. The introduction of nanosized silicon oxide suspension under the conditions of chronic combined intoxication did not statistically significantly change the total NOS activity and cNOS activity compared to the group exposed to chronic intoxication. However, iNOS activity reduces in 3.69 times. Nitrate reductase activity decreases in 1.6 times, while nitrite reductase activity decreases in 45%. The activity of arginases lowered in 2.38 times. The nitrite content of the testes cut down by 23.6%.
 Conclusions. Chronic combined nitrate-fluoride intoxication leads to the development of hyperproduction of nitric oxide in the testes of rats by activating the inducible isoform of NO synthase and nitrite reductases. The use of nanosized silica suspension during chronic combined intoxication is an effective method to correct nitric oxide overproduction in the testes of rats.

Ligands of Alpha‐1 Adrenergic Receptors: Common Signaling Pathway, but Different Sensitivity to Nitric Oxide in Sepsis

We have shown that arteries present differential responses to α1 adrenergic receptors (α1ARs) agonists in sepsis (Bernardelli et al., Can J Physiol Pharmacol, 94, 1227–36, 2016). Indeed, in animals subjected to the cecal ligation and perforation (CLP) model of sepsis, activation of α1ARs by norepinephrine (NE) results in a small degree of hyporesponsiveness, compared with the responses generated by phenylephrine (PE). It is well known that increased amounts of nitric oxide (NO) are produced in sepsis. NO plays a crucial role in septic vasoplegia, so we hypothesized that α1ARs agonists could differentially modulate the activity of NO synthases (NOS). Here, endothelium‐intact aortic rings from male Wistar rats subjected to CLP were studied in organ baths at 6 h after the septic insult. Control experiments were conducted with arteries from naïve animals. The effects of increasing concentrations (1 nM–300 mM) of PE and NE were evaluated in preparations previously incubated with L‐NAME (a non‐selective inhibitor of NOS; 100 μM), 1400W (a selective inhibitor of the inducible isoform of NOS; 10 μM), or S‐Methyl‐L‐thiocitrulline (a selective inhibitor of the neuronal isoform of NOS; 10 μM). We also investigated the influence of sodium nitroprusside (SNP; 0.1 μM, during 30 min) in the responses of control arteries to PE and NE. Aortic sections were also evaluated in experiments using the fluorescent BODIPY® FL prazosin (QAPB) (250 nM) and DAF‐FM (10 μM). Incubation with L‐NAME increased the contractile effects of PE and NE in both the control and CLP group. On the other hand, both 1400W and S‐methyl‐L‐thiocitrulline had no influence in the effects of PE and NE in control preparations, and increased the responses to PE (but not to NE) from 1.31 ± 0.06 g in control to 2.24 ± 0.11 and 2.21 ± 0.14 g, respectively, in the CLP group (p < 0.05). The fluorescence of QAPB in aortic sections did not differ between the groups, regardless of the previous incubation with PE or NE, suggesting that there were no significant differences in the density of α1ARs between the groups. Besides, neither PE nor NE were able to increase NO production, as detected by the NO sensitive fluorescence probe DAF‐FM. Interestingly, incubation with SNP reduced the maximal contractile effect of NE and PE by 35 and 65%, respectively (p < 0.05). These results suggest that neither an impaired interaction of PE and NE with α1ARs nor a differential modulation of NO production account for the distinct degree of vascular hyporeactivity observed. Nevertheless, our findings reveal remarkable differences between the intracellular signaling activated by PE and NE, regarding their sensitivity to NO. The better comprehension of the behavior of α1ARs can allow the development of ligands with enhanced efficacy for the management of vasoplegia and hypotension in sepsis.Support or Funding InformationFinancial Support: CNPq (Brazil), with a Ph.D. fellowship to Bernardelli, A. K. This study was approved by the Animal Ethics Committee of UFSC (6327180718).

QUERCETIN LIMITS THE PROGRESSION OF OXIDATIVE AND NITROSATIVE STRESS IN THE RATS’ TISSUES AFTER EXPERIMENTAL TRAUMATIC BRAIN INJURY

The aim: To investigate the effect of water-soluble form of quercetin on the indices reflecting the progression of oxidative-nitrosative stress in the cerebral tissues and the periodontium of rats after experimental TBI. Materials and methods: The studies were conducted on 30 white rats of the Wistar line weighing 180-220 g, divided into 3 groups: the 1st group included pseudo-injured animals (subjected to ether anaesthesia, fixation without TBI modeling), the 2nd group included the animals exposed to modeled moderate TBI, the 3rd group involved the rats, which were given injections with water-soluble form of quercetin (corvitin, "Borshchahivskiy CPP", Ukraine) intraperitoneally in a daily dose of 10 mg/kg recalculated for quercetin for 7 days following the TBI modeling. The formation of superoxide radical anion (.О2 -), activity of NO-synthase - total (NOS), its constitutive and inducible isoforms (cNOS, iNOS) - and concentration of peroxynitrite were evaluated spectrophotometrically. The level of lipid peroxidation (LPO) in the tissues was evaluated by the formation of a stained trimethine complex during the reaction of tiobarbituric acid (TBA). The activity of the antioxidant system was assessed by increasing in the concentration of TBA active products during 1.5 hour incubation in iron-ascorbate buffer solution, as well as by the activity of antioxidant enzymes - superoxide dismutase (SOD) and catalase. Results: The use of quercetin under the experimental conditions significantly reduced the О2 - generation by NADPH- and NADH-dependent electron transport chains by 30.2 and 35.0% (in the cerebral hemispheres) and by 23.5 and 32.5% (in the soft periodontal tissues), respectively, compared to the findings in the 2nd group. The production of this radical by leukocyte NADPH oxidase in these organs was inferior to the value of the 2nd group by 39.3 and 29.9%. We revealed that the use of quercetin in the experimental conditions probably reduced the activity of NOS, including iNOS, by 38.2 and 45.3% (in the cerebral hemispheres) and by 53.5 and 66.9% (in the soft periodontal tissues), respectively, compared with the findings in the 2nd group. Under these conditions, the cNOS activity went up by 50.0% and doubled, the peroxynitrite content was lower by 19.5 and 32.1% than that in the 2nd group. The administration of quercetin in the experimental conditions significantly reduced the concentration of TBA-active products in the homogenate of cerebral hemispheres and soft periodontal tissues. The development of decompensated LPO is also confirmed by a decrease in the activity of SOD and catalase. Conclusions: on the 7th day after modeling moderate TBI in rats the signs of oxidative-nitrosative stress are found not only in locus morbi (in the tissue of the cerebral hemisphere), but also in distant organs (periodontal tissues). Applying of water-soluble form of quercetin significantly reduces signs of oxidative-nitrosative stress in the tissue of the cerebral hemisphere of rats, as well as in periodontal tissues on the 7th day after moderate TBI modeling.

Pregnant mice submitted to Surgical Embryo Euthanasia (SEE) induce loss of expression of inducible nitric oxide synthase isoform and NO concentration in the maternal-fetal interface

The well-succeeded pregnancy in humans and rodents is the consequence of close interaction between maternal and fetal cells with intervening of cytokines and chemical mediators. In this process a pregnant uterus subset NK cells - uterine Natural Killer cells (uNK cells) play a pivotal modulatory role under the influence of local physiological hypoxia and other alterations. The aim of the present work was to evaluate the expression and commitment of induced form of nitric oxide synthase (iNOS) and NO concentration in the homeostasis of pregnant uterus. It was used normal pregnant mice on gd 10th and those submitted to surgical intervention to induce mechanical lesion in the embryos (SEE). Uterine samples were collected at 0.5, 1, 2 and 6 h after embryo lesion and processed for paraffin embedding and tissue homogenate. The samples destinate for paraffin embedding was performed the Dolichos biflorus (DBA) lectin cytochemistry and anti-iNOS immunocytochemistry. The samples destinate to tissue homogenates were processed for SDS-PAGE and Western-blot using anti-iNOS and evaluate of NO concentration. The embryo-injured uterine segments showed hyperemia and hemorrhage at mesometrial region in which the DBA lectin reaction showed altered uNK cells suggesting the degranulation. Positive reaction with anti-iNOS was seen on uNK cells, trophoblast giant cells, endometrial stromal and decidual cells and smooth muscle cells in the normal pregnant uterus, but 1 and 2 h after embryo lesion, the iNOS labeling decreased or was absent only in uNK cells. The same results was obtained with NO concentration. These results confirm the unique constitutive expression of iNOS in the pregnant mice uterus, being the uNK cells the only one responsive against stress of embryo failure, besides showing that excessive NO produced by quick activation of uNK-iNOS should affect the local vascular permeability.

Tuning PFKFB3 Bisphosphatase Activity Through Allosteric Interference

The human inducible phospho-fructokinase bisphosphatase isoform 3, PFKFB3, is a crucial regulatory node in the cellular metabolism. The enzyme is an important modulator regulating the intracellular fructose-2,6-bisphosphate level. PFKFB3 is a bifunctional enzyme with an exceptionally high kinase to phosphatase ratio around 740:1. Its kinase activity can be directly inhibited by small molecules acting directly on the kinase active site. On the other hand, here we propose an innovative and indirect strategy for the modulation of PFKFB3 activity, achieved through allosteric bisphosphatase activation. A library of small peptides targeting an allosteric site was discovered and synthesized. The binding affinity was evaluated by microscale thermophoresis (MST). Furthermore, a LC-MS/MS analytical method for assessing the bisphosphatase activity of PFKFB3 was developed. The new method was applied for measuring the activation on bisphosphatase activity with the PFKFB3-binding peptides. The molecular mechanical connection between the newly discovered allosteric site to the bisphosphatase activity was also investigated using both experimental and computational methods.

Suppressing aberrant phospholipase D1 signaling in 3xTg Alzheimer\u2019s disease mouse model promotes synaptic resilience

Current approaches in treatment of Alzheimer’s disease (AD) is focused on early stages of cognitive decline. Identifying therapeutic targets that promote synaptic resilience during early stages may prevent progressive memory deficits by preserving memory mechanisms. We recently reported that the inducible isoform of phospholipase D (PLD1) was significantly increased in synaptosomes from post-mortem AD brains compared to age-matched controls. Using mouse models, we reported that the aberrantly elevated neuronal PLD1 is key for oligomeric amyloid driven synaptic dysfunction and underlying memory deficits. Here, we demonstrate that chronic inhibition using a well-tolerated PLD1 specific small molecule inhibitor is sufficient to prevent the progression of synaptic dysfunction during early stages in the 3xTg-AD mouse model. Firstly, we report prevention of cognitive decline in the inhibitor-treated group using novel object recognition (NOR) and fear conditioning (FC). Secondly, we provide electrophysiological assessment of better synaptic function in the inhibitor-treated group. Lastly, using Golgi staining, we report that preservation of dendritic spine integrity as one of the mechanisms underlying the action of the small molecule inhibitor. Collectively, these studies provide evidence for inhibition of PLD1 as a potential therapeutic strategy in preventing progression of cognitive decline associated with AD and related dementia.

Inhibition of breast tumor growth by N(G)-nitro-l-arginine methyl ester (l-NAME) is accompanied by activation of fibroblasts

Nitric Oxide (NO) is involved in many physiological and pathological processes. It is generated by a family of NO synthases (NOS), being the inducible isoform, iNOS, responsible for higher amounts of NO. Here, we report that pharmacological inhibition of NO production by l-NAME reduces both viability and MAPK activated signalling pathways in iNOS positive human and murine cancer cell lines. In vivo, using syngeneic models, in parallel with tumor reduction induced by l-NAME, collagen deposition and α-SMA positive stromal cells are observed. This observation takes place only when tumor cells express iNOS. In vitro, l-NAME induces viability and differentiation on fibroblast. Our results reveal that NO inhibition contributes to stimulate proliferation and activation of fibroblasts in parallel with tumor reduction of iNOS positive breast cancer.

The Role of Heme Oxygenase-1 in Remote Ischemic and Anesthetic Organ Conditioning.

The cytoprotective effects of the heme oxygenase (HO) pathway are widely acknowledged. These effects are mainly mediated by degradation of free, pro-oxidant heme and the generation of carbon monoxide (CO) and biliverdin. The underlying mechanisms of protection include anti-oxidant, anti-apoptotic, anti-inflammatory and vasodilatory properties. Upregulation of the inducible isoform HO-1 under stress conditions plays a crucial role in preventing or reducing cell damage. Therefore, modulation of the HO-1 system might provide an efficient strategy for organ protection. Pharmacological agents investigated in the context of organ conditioning include clinically used anesthetics and sedatives. A review from Hoetzel and Schmidt from 2010 nicely summarized the effects of anesthetics on HO-1 expression and their role in disease models. They concluded that HO-1 upregulation by anesthetics might prevent or at least reduce organ injury due to harmful stimuli. Due to its clinical safety, anesthetic conditioning might represent an attractive pharmacological tool for HO-1 modulation in patients. Remote ischemic conditioning (RIC), first described in 1993, represents a similar secure option to induce organ protection, especially in its non-invasive form. The efficacy of RIC has been intensively studied herein, including on patients. Studies on the role of RIC in influencing HO-1 expression to induce organ protection are emerging. In the first part of this review, recently published pre-clinical and clinical studies investigating the effects of anesthetics on HO-1 expression patterns, the underlying signaling pathways mediating modulation and its causative role in organ protection are summarized. The second part of this review sums up the effects of RIC.