Placenta-derived IL-32β activates neutrophils to promote preeclampsia development

Immune activation at the maternal-fetal interface is a main pathogenic factor of preeclampsia (PE). Neutrophils (PMNs) are activated in PE patients, but the mechanism and consequences of PMN activation need to be further explored. Here, we demonstrated that interleukin-32 (IL-32) expression was significantly upregulated in syncytiotrophoblasts (STBs) and that IL-32β was the major isoform with increased expression in the placenta of severe PE (sPE) patients. Furthermore, the level of IL-32 expression in the placenta was correlated with its level in the serum of sPE patients, indicating that IL-32 in the serum is derived mainly from the placenta. Then, in vitro experiments showed that IL-32β could highly activate PMNs and that these IL-32β-activated PMNs were better able to adhere to endothelial cells (HUVECs) and enhance the expression of vascular cell adhesion molecule-1 (VCAM-1) and intercellular cell adhesion molecule-1 (ICAM-1) in HUVECs, which could be reversed by preincubation with the NADPH oxidase inhibitor VAS 2870. In addition, we showed that IL-32β mainly activated PMNs by binding to proteinase 3. Finally, IL-32β administration induced a PE-like phenotype in a pregnant mouse model. This study provides evidence of the involvement of IL-32β in the pathogenesis of PE.

Implication of Nicotinamide Adenine Dinucleotide Phosphate (NADPH) Oxidase and Its Inhibitors in Alzheimer’s Disease Murine Models

Alzheimer’s disease (AD) is one of the main human dementias around the world which is constantly increasing every year due to several factors (age, genetics, environment, etc.) and there are no prevention or treatment options to cure it. AD is characterized by memory loss associated with oxidative stress (OS) in brain cells (neurons, astrocytes, microglia, etc.). OS can be produced by amyloid beta (Aβ) protein aggregation and its interaction with metals, mitochondrial damage and alterations between antioxidants and oxidant enzymes such as nicotinamide adenine dinucleotide phosphate (NADPH) oxidase. NADPH oxidase produces reactive oxygen species (ROS) and it is overexpressed in AD, producing large amounts of superoxide anions and hydrogen peroxide which damage brain cells and the vasculature. In addition, it has been reported that NADPH oxidase causes an imbalance of pH which could also influence in the amyloid beta (Aβ) production. Therefore, NADPH oxidase had been proposed as a therapeutic target in AD. However, there are no drugs for AD treatment such as an NADPH oxidase inhibitor despite great efforts made to stabilize the ROS production using antioxidant molecules. So, in this work, we will focus our attention on NADPH oxidase (NOX2 and NOX4) in AD as well as in AD models and later discuss the use of NADPH oxidase inhibitor compounds in AD.

The effect of cadaverine on redox homeostasis of wheat seedling roots and their resistance to damage heating

Polyamines are plant metabolites involved in many processes under physiologically normal and stressful conditions. Cadaverine is one of the least studied plant polyamines. The relationship between its physiological effects and the formation of signaling mediators, in particular, reactive oxygen species (ROS), has hardly been specially studied. The aim of this work was to study the possible protective effect of cadaverine on wheat (Triticum aestivum L.) seedlings under heat stress and its relationship with the formation and detoxification of ROS by antioxidant enzymes. Etiolated seedlings of soft winter wheat variety Doskonala were used in the work. We treated three-day-old seedlings with cadaverine at concentrations ranging from 0.05 to 2.5 mM by adding it to the root incubation medium. In some variants of the experiment, we treated seedlings with a hydrogen peroxide scavenger dimethylthiourea (DMTU - 150 μM), a diamine oxidase inhibitor aminogunidine (1 mM) or an inhibitor NADPH oxidase imidazole (10 μM), as well as the indicated inhibitors in combination with cadaverine. The hydrogen peroxide content and the activity of antioxidant enzymes were determined in the roots of seedlings a certain time after treatment with the studied compounds. One day after the treatment of seedlings with cadaverine, ROS antagonists, and a combination of effectors, the seedlings were subjected to damaging heating in a water thermostat (10 min at 45 °C). 24 h after heating, we assessed the content of the products of lipid peroxidation (LPO) in the roots and, after 3 days, the survival of seedlings. Incubation in the presence of cadaverine increased the resistance of seedlings to damaging heat (See Fig. 1). The highest relative number of surviving seedlings was observed in the variant with 1 mM cadaverine treatment. Under the effect of cadaverine, the content of hydrogen peroxide in the roots increased (See Fig. 2). We observed a noticeable effect 1-4 h after the start of treatment, with a maximum after 2 h. Treatment of seedlings with a scavenger of hydrogen peroxide DMTU removed the manifestation of the effect of an increase in the content of H2 O2 in the roots caused by the action of cadaverine (See Fig. 3). This effect was also completely eliminated by the diamine oxidase inhibitor aminoguanidine and was almost unchanged in the presence of the NADPH oxidase inhibitor imidazole. The effect of heat stress on seedlings caused an increase in the content of the LPO products in them. Treatment with cadaverine markedly reduced this manifestation of oxidative stress. The antioxidant DMTU and the diamine oxidase inhibitor aminoguanidine largely neutralized the protective effect of cadaverine (See Fig. 4a). At the same time, the NADPH oxidase inhibitor imidazole had almost no effect on the manifestation of the effect of cadaverine on the LPO products content in roots. Under the influence of DMTU and aminoguanidine, but not imidazole, the positive effect of cadaverine on the survival of seedlings after damaging heating was also leveled out (See Fig. 4b). The treatment of seedlings with cadaverine caused a change in the activity of antioxidant enzymes in the roots (superoxide dismutase - SOD, catalase, and guaiacol peroxidase) (See Fig. 5). DMTU and aminoguanidine neutralized the effect of cadaverine-induced increase in the activity of catalase and guaiacol peroxidase, but had almost no effect on the increase in SOD activity in roots induced by this diamine (See Fig. 6). The NADPH oxidase inhibitor imidazole did not significantly affect the manifestation of the effect of increasing the activity of antioxidant enzymes when seedlings are treated with cadaverine. We can conclude that one of the signaling mediators involved in the regulation activity of catalase and guaiacol peroxidase and in the induction of heat resistance of wheat seedlings by exogenous cadaverine is hydrogen peroxide, which is formed during the oxidation of cadaverine by diamine oxidase. At the same time, the modification of SOD activity in the roots of wheat seedlings with cadaverine, apparently, can occur without the participation of ROS.

Development of a caffeic acid–phthalimide hybrid compound for NADPH oxidase inhibition

The incorporation of the phthalimide moiety into caffeic acid was decisive for its effectiveness as an NADPH oxidase inhibitor.

DUOX2 is a Generator of ROS in the Ovary and a Potential Mediator of Ovulation

Background: Ovulation is triggered by the preovulatory surge of the pituitary luteinizing hormone (LH). LH/hCG induction of reactive oxygen species (ROS) is required for successful ovulation. H2O2, one of ROS species, was shown to fully mimic the effect of LH/hCG in mice ovulation. However, the molecular process that generates H2O2 in the ovary during ovulation remains largely unknown. DUOX2, a member of the NOX/DUOX family of NADPH oxidase, is capable of generating H2O2. Results: Using global transcriptome RNAseq, we identified that DUOX2 is one of the transcripts that was markedly upregulated in granulosa cells during ovulation. Treatment with human chorionic gonadotropin (hCG), an ovulatory trigger, significantly increases the expression of DUOX2 mRNA and protein in human GCs both in vivo and in vitro. hCG-induced up-regulation of DUOX2 is mediated by the cAMP-PKA and the PKC pathway. A functional test reveals that DUOX2 chemical inhibitor, Diphenyleneiodonium (DPI), an NADPH oxidase inhibitor, decreased H2O2 levels in MGCs (Mural Granulosa Cells) treated with hCG. The inhibition of H2O2 by DPI suggests that DUOX2 activity is required for hCG-induced elevation of extracellular H2O2 in MGCs. In vivo treatment of mice with DPI significantly decreases the number of ovulated oocytes and markedly attenuates the expression of key ovulatory genes. These results support the putative role of DUOX2 in ovulation. Conclusions: DUOX2 is a ROS generator during the ovulatory process and is involved in the LH/hCG-induced signaling cascades leading to ovulation. Treatment with DUOX2 inhibitors may affect late folliculogenesis and ovulation and thus may serve for fertility control.