NADPH oxidase is a primary target for antioxidant effects by inorganic nitrite in lipopolysaccharide-induced oxidative stress in mice and in macrophage cells

Impact of chlorogenic acid on submandibular salivary gland and liver of albino rats exposed to sodium nitrite

AIM

The aim of the present study is to show how sodium nitrite alters the histology of submandibular salivary glands and livers of Albino rats, as well as how chlorogenic acid may have therapeutic benefits.

METHODS

A sample size of thirty male Sprague Dawley Albino rats weighing between 100 and 150 g (5-6 weeks old) was randomly allocated into 3 equal groups. Group I: rats were used as controls and were given phosphate buffer solution, whereas Group II: rats were given an 80 mg/kg sodium nitrites (SN) daily dissolved in distilled water. The rats in Group III were given a daily dose of 80 mg/kg SN dissolved in distilled water and after 6 hours each rat received 50 mg/mL freshly prepared chlorogenic acid (CGA) every other day. For 12 weeks, all treatment modalities will be administered orally, every day. After the experiment, all rats were euthanized. Samples from salivary glands and livers were processed and stained with H&E and interleukin 6 (IL 6). Malondialdehyde (MDA) and superoxide dismutase (SOD) enzymes were detected using an ELISA assay.

RESULTS

Groups III had nearly comparable findings to Group I regarding histological pattern with normal submandibular glands and livers features. Group III salivary gland treated with CGA exhibited higher SOD levels (20.60±4.81 U/g) in comparison to the SN group, and lower MDA levels (111.58±28.28 nmol/mg) in comparison to the SN treated samples. In comparison to the SN group, CGA treatment significantly reduced MDA levels in liver samples (167.56±21.17 nmol/mg) and raised SOD (30.85±6.77 U/g).

CONCLUSIONS

Chlorogenic acid has a protective effect against salivary gland and liver toxicity induced by SN in rats. This was mediated via the anti-inflammatory and antioxidative properties of CGA and the restoration of oxidant/antioxidant balance in rat salivary gland and liver.

The Nitrate-Nitrite-Nitric Oxide Pathway: Potential Role in Mitigating Oxidative Stress in Hypertensive Disorders of Pregnancy

Hypertensive diseases of pregnancy (HDPs) represent a global clinical challenge, affecting 5-10% of women and leading to complications for both maternal well-being and fetal development. At the heart of these complications is endothelial dysfunction, with oxidative stress emerging as a pivotal causative factor. The reduction in nitric oxide (NO) bioavailability is a vital indicator of this dysfunction, culminating in blood pressure dysregulation. In the therapeutic context, although antihypertensive medications are commonly used, they come with inherent concerns related to maternal-fetal safety, and a percentage of women do not respond to these therapies. Therefore, alternative strategies that directly address the pathophysiology of HDPs are required. This article focuses on the potential of the nitrate-nitrite-NO pathway, abundantly present in dark leafy greens and beetroot, as an alternative approach to treating HDPs. The objective of this review is to discuss the prospective antioxidant role of nitrate. We hope our discussion paves the way for using nitrate to improve endothelial dysfunction and control oxidative stress, offering a potential therapy for managing HDPs.

TOM40 mediates the effect of TSPO on postpartum depression partially through regulating calcium homeostasis in microglia

AIMS

To assess the effect of the translocator protein 18 kDa (TSPO) on postpartum depression and explore its mechanism.

METHODS

Postpartum depression (PPD) mouse model was established, and flow cytometry, immunofluorescence, Western blot analysis, real-time quantitative PCR, adeno-associated virus (AAV), co-immunoprecipitation-mass spectrometry and immunofluorescence co-staining were used to detect the effect of TSPO ligand ZBD-2 on PPD mice.

RESULTS

ZBD-2 inhibits the overactivation of microglia in the hippocampus and amygdala of PPD model mice. ZBD-2 not only inhibited the inflammation but also repressed the burst of reactive oxygen species (ROS) and mitochondrial ROS (mtROS). Meanwhile, ZBD-2 protects mitochondria from LPS-induced damages through inhibiting the influx of calcium. ZBD-2 modulated the calcium influx by increasing the level of translocase of the outer mitochondrial membrane 40 (TOM40) and reducing the interaction of TSPO and TOM40. In addition, the effect of ZBD-2 was partially dependent on anti-oxidative process. Knockdown of TOM40 by adeno-associated virus (AAV) in the hippocampus or amygdala dramatically reduced the effect of ZBD-2 on PPD, indicating that TOM40 mediates the effect of ZBD-2 on PPD.

CONCLUSIONS

TOM40 is required for the effect of ZBD-2 on treating anxiety and depression in PPD mice. This study reveals the role of microglia TSPO in PPD development and provides the new therapeutic strategy for PPD.

Inorganic Nitrogen-Containing Aerosol Deposition Caused “Excessive Photosynthesis” of Herbs, Resulting in Increased Nitrogen Demand

The amount of atmospheric nitrogen-containing aerosols has increased dramatically due to the globally rising levels of nitrogen from fertilization and atmospheric deposition. Although the balance of carbon and nitrogen in plants is a crucial component of physiological and biochemical indexes and plays a key role in adaptive regulation, our understanding of how nitrogen-containing aerosols affect this remains limited; in particular, regarding the associated mechanisms. Using a fumigation particle generator, we generated ammonium nitrate solution (in four concentrations of 0, 15, 30, 60 kg N hm⁻² year⁻¹) into droplets, in 90% of which the diameters were less than 2.5 μm, in the range of 0.35–4 μm, and fumigated Iris germanica L. and Portulaca grandiflora Hook. for 30 days in April and August. We found that the weight percentage of nitrogen in the upper epidermis, mesophyll tissue, and bulk of leaves decreased significantly with the N addition rate, which caused a decrease of carbon:nitrogen ratio, due to the enhanced net photosynthetic rate. Compared with Portulaca grandiflora Hook., Iris germanica L. responded more significantly to the disturbance of N addition, resulting in a decrease in the weight percentage of nitrogen in the roots, due to a lower nitrogen use efficiency. In addition, the superoxide dismutase activity of the two plants was inhibited with a higher concentration of nitrogen sol; a reduction of superoxide dismutase activity in plants means that the resistance of plants to various environmental stresses is reduced, and this decrease in superoxide dismutase activity may be related to ROS signaling. The results suggest that inorganic nitrogen-containing aerosols caused excessive stress to plants, especially for Iris germanica L.

Heart-targeted amelioration of sepsis-induced myocardial dysfunction by microenvironment responsive nitric oxide nanogenerators in situ

Background

A balanced endogenous level of bioavailable nitric oxide (NO) plays a key role in maintaining cardiovascular homeostasis. The bioactive NO level in the cardiomyocytes was much reduced during sepsis. However, it is clinically challenging for the NO gas therapy due to the lack of spatial and temporal release system with precise control. The purpose of this study is to design a NO-releasing biomaterial with heart-targeted capability responsive to the infectious microenvironment, thus ameliorating lipopolysaccharide (LPS)-induced cardiac dysfunction.

Results

The heart-targeted NO delivery and in situ releasing system, PCM-MSN@LA, was synthesized using hollow mesoporous silica nanoparticles (MSN) as the carrier, and L-arginine (LA) as the NO donor. The myocardial delivery was successfully directed to heart by specific peptide (PCM) combined with low-intensity focused ultrasound (LIFU) guidance. The myocardial system synthesized NO from the LA released from PCM-MSN@LA in the presence of increased endogenous nitric oxide synthase (NOS) activity induced by LPS. This targeted NO release in situ achieved extraordinary protective effects against LPS-challenged myocardial injury by reducing the recruitment of inflammatory cells, inhibiting oxidative stress and maintaining the mitochondria integrity. In particular, this protection was not compromised by simultaneous circulation collapse as an adverse event in the context.

Conclusions

PCM-MSN@LA + LIFU exhibited extraordinary cardioprotective effects against severe sepsis in the hearts of LPS-treated animals without the side effect of NO diffusion. This technology has great potential to be served as a novel therapeutic strategy for sepsis-induced myocardial injury.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12951-022-01457-y.

Indolium 1 Exerts Activity against Vemurafenib-Resistant Melanoma In Vivo

The development of targeted therapies (BRAF/MEK inhibitors) and immunotherapy have had a major impact on the treatment of melanoma. However, the majority of patients with advanced melanomas succumb to their disease. The mechanisms of resistance to both targeted therapies and immunotherapies are numerous and have been well-described. These include the alternative activation of BRAF/MEK signaling, novel compensating mutations in additional oncogenes, and loss of neoantigens. There has been limited development of small molecules that target alternative pathways in melanoma in the last two decades. We have previously identified triphenylmethanes as a class that shows activity against a wide variety of tumors. We have synthesized a novel triphenylmethane, indolium 1, and demonstrated its efficacy against an aggressive vemurafenib-resistant melanoma in vivo. Indolium 1 has a novel mechanism of action against melanoma, in that it results in induction of the tumor-suppressor EPHA3. We believe that pre-IND studies are warranted for this novel compound, given its mechanism of action and ability to inhibit the growth of vemurafenib resistant melanoma in vivo.

Mediterranean diet and cognitive function: From methodology to mechanisms of action

The traditional Mediterranean diet (MedDiet), rich in minimally processed plant foods and fish, has been widely recognized to be one of the healthiest diets. Data from multiple randomized clinical trials have demonstrated its powerful effect against oxidative stress, inflammation and the development and progression of cardiovascular disease, type 2 diabetes, and other metabolic conditions that play a crucial role in the pathogenesis of neurodegenerative diseases. The protecting effects of the MedDiet against cognitive decline have been investigated in several observational and experimental studies. Data from observational studies suggest that the MedDiet may represent an effective dietary strategy for the early prevention of dementia, although these findings require further substantiation in clinical trials which have so far produced inconclusive results. Moreover, as we discuss in this review, accumulating data emphasizes the importance of: 1) maintaining an optimal nutritional and metabolic status for the promotion of healthy cognitive aging, and 2) implementing cognition-sparing dietary and lifestyle interventions during early time-sensitive windows before the pathological cascades turn into an irreversible state. In summary, components of the MedDiet pattern, such as essential fatty acids, polyphenols and vitamins, have been associated with reduced oxidative stress and the current evidence from observational studies seems to assign to the MedDiet a beneficial role in promoting brain health; however, results from clinical trials have been inconsistent. While we advocate for longitudinal analyses and for larger and longer clinical trials to be conducted, we assert our interim support to the use of the MedDiet as a protective dietary intervention for cognitive function based on its proven cardiovascular and metabolic benefits.

Loss of QKI in macrophage aggravates inflammatory bowel disease through amplified ROS signaling and microbiota disproportion

Inflammatory bowel disease (IBD) is a refractory chronic inflammatory illness of the gastrointestinal (GI) tract. Macrophage exerts an important role in IBD development. QKI, as an RNA binding protein, was related with inflammatory responses in bacterial infections by regulating the polarization of macrophages. Therefore, we suspected that QKI-regulated macrophages have the potential to play a certain role in IBD and the underlying mechanism. Our results demonstrated that the mice with macrophage-specific deletion of QKI induced with dextran sodium sulfate (DSS) are more susceptible to IBD development, exhibited a severe leaky gut barrier phenotype and higher intense oxidative stress, which are rescued by treating with butylated hydroxyanisole (BHA), an agonist of NRF2. Mechanically, we observed that Keap1 mRNA in the nucleus was exported to the cytoplasm after LPS stimuli in parallel with QKI reductions, and the removal of QKI by shRNA facilitated Keap1 mRNA nuclear exporting and expression in cytoplasm, consequently NRF2 activation in nucleus was weakened, and led to the impaired antioxidant abilities. In addition, mice models of fecal microbiota transplant (FMT) and the co-culturing of mice epithelia cells with feces derived from the DSS-treated QKI-deficit mice revealed consistently aggravated colitis along with a severe oxidative stress; 16S sequencing analysis substantiated the altered compositions of commensal bacteria too. Overall, the current study represents the first effort to explore the anti-oxidant role of QKI in the intestinal macrophage via post-transcriptional regulation of Keap1 mRNA localization and the relevant NRF2 antioxidant signaling, and the disproportional changes in the microbiota were attributable to the mediation of pathogenic damage in the IBD development of QKI-deficit mice.

Dietary nitrate attenuated endothelial dysfunction and atherosclerosis in apolipoprotein E knockout mice fed a high-fat diet: A critical role for NADPH oxidase

Nitric oxide (NO) deficiency and NADPH oxidase plays key roles in endothelial dysfunction and atherosclerotic plaque formation. Recent evidence demonstrates that nitrate-nitrite-NO pathway in vivo exerts beneficial effects upon the cardiovascular system. We aimed to investigate the effects of dietary nitrate on endothelial function and atherosclerosis in apolipoprotein E knockout (ApoE^-/-) mice fed a high-fat diet. It was shown that dietary nitrate significantly attenuated aortic endothelial dysfunction and atherosclerosis in ApoE^-/- mice. Mechanistic studies revealed that dietary nitrate significantly improved plasma nitrate/nitrite, inhibited vascular NADPH oxidase activity and oxidative stress in ApoE^-/- mice, while xanthine oxidoreductase (XOR) expression and activity was enhanced in ApoE^-/- mice in comparison with wide type animals. These beneficial effects of nitrate in ApoE^-/- mice were abolished by PTIO (NO scavenger) and significantly prevented by febuxostat (XOR inhibitor). In the presence of nitrate, no further effect of apocynin (NADPH oxidase inhibitor) was observed, suggesting NADPH oxidase as a possible target. In vitro, NO donor significantly inhibited NADPH oxidase activity in vascular endothelial cells via the induction of heme oxygenase-1. Altogether, boosting this nitrate-nitrite-NO signaling pathway resulted in the decreases of vascular NADPH oxidase-derived oxidative stress and endothelial dysfunction, and consequently protected ApoE^-/- mice against atherosclerosis. These findings may have novel nutritional implications for the preventive and therapeutic strategies against vascular endothelial dysfunction in atherosclerotic disease.

Neuroprotective effect from Salvia hispanica peptide fractions on pro-inflammatory modulation of HMC3 microglial cells

Neuroinflammation plays a critical role in the neurodegenerative disease's development, where microglia's act an important role in the mechanisms of response to neuronal damage. In the present research, the neuroprotective effect from Salvia hispanica peptide fractions on the proinflammatory modulation on HMC3 microglial cells was evaluated. From the enzymatic hydrolysis of a protein-rich fraction from S. hispanica seeds, three peptide fractions (<1, 1-3 and 3-5 kDa) were obtained, from which its neuroprotective and anti-inflammatory effect was determined on the production of proinflammatory mediators on HMC3 cells. The F1-3 kDa exhibited the greatest protective effect (79.04%), associated with the decrease in ROS cell production (51.3 ± 2.3%). Likewise, F1-3 kDa at 50 µg/ml, presented the highest reduction percentages of NO (33.1 ± 2.30%), TNFα (26.4 ± 1.1%) and IL6 (17.36 ± 1.6%). F1-3 kDa exhibited a neuroprotective effect in HMC3 cells associated with its antioxidant and anti-inflammatory effect. PRACTICAL APPLICATIONS: Currently, neurodegenerative diseases represent a global health problem, so the search for bioactive compounds with neuroprotective effect is useful in the prevention and treatment of this group of diseases. Peptide research with an effect on the proinflammatory and prooxidant mediator's reduction presents a potential application in the functional food's development aimed at the treatment of chronic diseases, that have oxidative stress and inflammation as their etiological factor. The present research adds to the scientific evidence of the potential benefits of bioactive peptides obtained from chia seeds. The results correlate with the main health benefits of whole chia seed in humans, such as antioxidant, anti-inflammatory, hypoglycemic and hypotensive capacity. This relationship is associated with the protein and peptide composition of chia, which increases its added value as food.

Supplementation of dietary nitrate attenuated oxidative stress and endothelial dysfunction in diabetic vasculature through inhibition of NADPH oxidase

The metabolic disorders in diabetes, which are usually accompanied by oxidative stress and impaired nitric oxide (NO) bioavailability, increase the risk of detrimental cardiovascular complications. Herein, we investigated the therapeutic potential of dietary nitrate, which is found in high content in green leafy vegetables, on vascular oxidative stress and endothelial dysfunction in diabetic mice induced by high-fat diet and streptozotocin injection. Dietary nitrate in drinking water fuelled a nitrate-nitrite-NO pathway, which inhibited vascular oxidative stress, endothelial dysfunction and many features of metabolic syndrome in diabetic mice. These beneficial effects of nitrate on diabetic mice were abolished by PTIO (NO scavenger) treatment and significantly prevented by febuxostat (xanthine oxidoreductase inhibitor), demonstrating the central importance of NO in bioactivation of nitrate. The favorable effects of nitrate were not further influenced by apocynin (NADPH oxidase inhibitor), suggesting NADPH oxidase as a possible target. In high glucose-incubated vascular endothelial cells, NO donor attenuated oxidative stress and endothelial dysfunction via the inhibition of NADPH oxidase, where a heme oxygenase-1 (HO-1)-dependent mechanism was demonstrated for the antioxidant abilities of NO. Altogether, boosting this nitrate-nitrite-NO signaling pathway resulted in the decreases of NADPH oxidase-derived oxidative stress, endothelial dysfunction and metabolic disorders in diabetic vasculature. These findings may have novel implications for the preventive strategy against diabetes-induced vascular dysfunction and associated complications.