Nitric Oxide Balance in Health and Diseases: Implications for New Treatment Strategies

Impacts of SARS-CoV-2 on brain renin angiotensin system related signaling and its subsequent complications on brain: A theoretical perspective

Cellular ACE2 (cACE2), a vital component of the renin-angiotensin system (RAS), possesses catalytic activity to maintain AngII and Ang 1-7 balance, which is necessary to prevent harmful effects of AngII/AT2R and promote protective pathways of Ang (1-7)/MasR and Ang (1-7)/AT2R. Hemostasis of the brain-RAS is essential for maintaining normal central nervous system (CNS) function. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a viral disease that causes multi-organ dysfunction. SARS-CoV-2 mainly uses cACE2 to enter the cells and cause its downregulation. This, in turn, prevents the conversion of Ang II to Ang (1-7) and disrupts the normal balance of brain-RAS. Brain-RAS disturbances give rise to one of the pathological pathways in which SARS-CoV-2 suppresses neuroprotective pathways and induces inflammatory cytokines and reactive oxygen species. Finally, these impairments lead to neuroinflammation, neuronal injury, and neurological complications. In conclusion, the influence of RAS on various processes within the brain has significant implications for the neurological manifestations associated with COVID-19. These effects include sensory disturbances, such as olfactory and gustatory dysfunctions, as well as cerebrovascular and brain stem-related disorders, all of which are intertwined with disruptions in the RAS homeostasis of the brain.

Probing calmodulin-NO synthase interactions via site-specific infrared spectroscopy: an introductory investigation

Calmodulin (CaM) binds to a linker between the oxygenase and reductase domains of nitric oxide synthase (NOS) to regulate the functional conformational dynamics. Specific residues on the interdomain interface guide the domain-domain docking to facilitate the electron transfer in NOS. Notably, the docking interface between CaM and the heme-containing oxygenase domain of NOS is isoform specific, which is only beginning to be investigated. Toward advancing understanding of the distinct CaM-NOS docking interactions by infrared spectroscopy, we introduced a cyano-group as frequency-resolved vibrational probe into CaM individually and when associated with full-length and a bi-domain oxygenase/FMN construct of the inducible NOS isoform (iNOS). Site-specific, selective labeling with p-cyano-L-phenylalanine (CNF) by amber suppression of CaM bound to the iNOS has been accomplished by protein coexpression due to the instability of recombinant iNOS protein alone. We introduced CNF at residue 108, which is at the putative CaM-heme (NOS) docking interface. CNF was also introduced at residue 29, which is distant from the docking interface. FT IR data show that the 108 site is sensitive to CaM-NOS complex formation, while insensitivity to its association with the iNOS protein or peptide was observed for the 29 site. Moreover, narrowing of the IR bands at residue 108 suggests the C≡N probe experiences a more limited distribution of environments, indicating side chain restriction apparent for the complex with iNOS. This initial work sets the stage for residue-specific characterizations of structural dynamics of the docked states of NOS proteins.

Atrazine exposure caused oxidative stress in male rats and inhibited brain-pituitary-testicular functions

Exposure to the herbicide atrazine has been shown to have deleterious effects on human and animal reproduction. To determine whether atrazine influences the brain-pituitary-testicular axis directly or indirectly, the present study examined the toxic effects of atrazine on fertility potential by assessing gonadal hormones, testicular function indices, sperm quality, and oxido-inflammatory markers in rats. Twelve animals were grouped into two groups; control and atrazine. The control group received oral administration of olive oil (2 mL/kg), while the atrazine group received 120 mg/kg of atrazine. Treatments were daily and lasted for 7 days. Upon treatment cessation, rats were necropsied for biochemical and histopathological analyses. The biochemical function indices in the rat brain, testis, and epididymis decreased significantly in the atrazine group. Atrazine exposure led to decreases in gonadal hormonal concentrations, semen quality parameters, and testicular function indices compared with the control. Furthermore, there was a marked increase in oxidative stress and inflammatory markers as well as degeneration of the histo-architecture in atrazine-treated rats. Overall, atrazine exposure impaired sperm quality, led to increased inflammation and oxidative stress, and decreased the activity of the brain-pituitary-testicular axis via endocrine disruption.

Pomegranate juice fermented by tannin acyl hydrolase and Lactobacillus vespulae DCY75 enhance estrogen receptor expression and anti-inflammatory effect

Phenolics are phytochemicals in plants, fruits, and vegetables have potential health-promoting efficacies. However, mostly available as a complex form. So, to increase the contents and nutritional value of the phenolic compounds, fermentation is most readily used in the food industry. Especially, the hydrolyzable tannins present in the pomegranate that can be liberated into monomolecular substances, which enhances biological activity. Thus, this study aims to convert hydrolyzable tannins to ellagic acid by fermentation using Tannin acyl hydrolase (TAH) and a novel bacteria strain Lactobacillus vespulae DCY75, respectively to investigate its effect on Estrogen receptor alpha (ERα) and estrogen receptor beta (ERβ) mRNA expression along with inflammation inhibition. As a result, the fermentation enhanced the ellagic acid content up to 70% by the synergetic effect of TAH and DCY75. Furthermore, fermented pomegranate (PG-F) increased cellular proliferation as well as upregulated the gene expression of estrogen regulators such as ERα, ERβ, and pS2 in breast cancer cell line (MCF-7), which commonly used to evaluate estrogenic activity. Moreover, to study the inflammation associated with low estrogen in menopause, we have analyzed the inhibition of nitric oxide (NO)/inducible nitric oxide synthase (iNOS) in RAW 264.7 cells. The PG-F juice did not exert any cytotoxicity in RAW 264.7 cells and inhibited NO production along with the downregulation of a major pro-inflammatory cytokine iNOS which indicates the anti-inflammatory potential of it. To sum it up, the fermented commercial pomegranate juice using a novel bacteria strain increased the amount of ellagic acid that the value added bioactive of pomegranate and it has significantly increased the estrogenic activity via upregulating estrogen related biomarkers expression and reduced the risk of related inflammation via NO/iNOS inhibition. This study could be a preliminary study to use fermented pomegranate as a potential health functional food after further evaluation.

Binary Effects of Gynostemma Gold Nanoparticles on Obesity and Inflammation via Downregulation of PPARγ/CEPBα and TNF-α Gene Expression

Nanoscience is a multidisciplinary skill with elucidated nanoscale particles and their advantages in applications to various fields. Owing to their economical synthesis, biocompatible nature, and widespread biomedical and environmental applications, the green synthesis of metal nanoparticles using medicinal plants has become a potential research area in biomedical research and functional food formulations. Gynostemma pentaphyllum (GP) has been extensively used in traditional Chinese medicine to cure several diseases, including diabetes mellitus (DM). This is the first study in which we examined the efficacy of G. pentaphyllum gold nanoparticles (GP-AuNPs) against obesity and related inflammation. GP extract was used as a capping agent to reduce Au²⁺ to Au⁰ to form stable gold nanoparticles. The nanoparticles were characterized by using UV–VIS spectroscopy, and TEM images were used to analyze morphology. In contrast, the existence of the functional group was measured using FTIR, and size and shape were examined using XRD analysis. In vitro analysis on GP-AuNPs was nontoxic to RAW 264.7 cells and 3T3-L1 cells up to a specific concentration. It significantly decreased lipid accumulation in 3T3-L1 obese and reduced NO production in Raw 264.7 macrophage cells. The significant adipogenic genes PPARγ and CEPBα and a major pro-inflammatory cytokine TNF-α expression were quantified using RT-PCR. The GP-AuNPs decreased the face of these genes remarkably, revealing the antiadipogenic and anti-inflammatory activity of our synthesized GP-AuNPs. This study represents thorough research on the antiobesity effect of Gynostemma pentaphyllum gold nanoparticles synthesized using a green approach and the efficacy instead of related inflammatory responses.

Biological reference interval of nitric oxide in health and disease

OBJECTIVES

There is a need to develop reference interval of NO in health and disease.

METHODS

Subjects aged between 25 and 55 years were drawn from a random sample of the north Indian population, based on defined inclusion and exclusion criteria. Measurement of NO was done based on principle of greiss reaction.

RESULTS

Reference interval of NO in healthy individual of age group 25-55 years was 21 ± 13.3 μM/L (n=350), Premenopausal women of age group 25-35 years was 12.7 ± 4.9 μM/L (n=180), Postmenopausal women of age group 40-55 years was 10.3 ± 3.84 μM/L (n=100) and healthy pregnant females of age group 25-35 years was 70.9 ± 15.95 μM/L (n=330). In pathological state group, reference interval of NO in metabolic syndrome cases of age group 25-55 years was 19.4 ± 15.3 μM/L (n=100), coronary artery disease patient of age group more than 35 years was 17.6 ± 10.8 μM/L (n=160), pregnancy induced hypertension (PIH) of age group 25-30 years was 45.7 ± 7.2 μM/L (n=330), pre-eclampsia patient of age group 25-35 years was 39.8 ± 14.7 μM/L (n=200) and diabetic individuals of age group of more than 30 years was 15.5 ± 1.4 μM/L (n=50).

CONCLUSIONS

The reference intervals presented may be used for various research purposes. Based upon our study, reference interval for NO levels of various disease states like MetS, CAD, diabetes, PIH showed lower levels of NO compared to their respective healthy group due to shared etiopathologies with decreased NO levels.

Glutathione in Protein Redox Modulation through S-Glutathionylation and S-Nitrosylation

S-glutathionylation and S-nitrosylation are reversible post-translational modifications on the cysteine thiol groups of proteins, which occur in cells under physiological conditions and oxidative/nitrosative stress both spontaneously and enzymatically. They are important for the regulation of the functional activity of proteins and intracellular processes. Connecting link and “switch” functions between S-glutathionylation and S-nitrosylation may be performed by GSNO, the generation of which depends on the GSH content, the GSH/GSSG ratio, and the cellular redox state. An important role in the regulation of these processes is played by Trx family enzymes (Trx, Grx, PDI), the activity of which is determined by the cellular redox status and depends on the GSH/GSSG ratio. In this review, we analyze data concerning the role of GSH/GSSG in the modulation of S-glutathionylation and S-nitrosylation and their relationship for the maintenance of cell viability.