Nitric Oxide Synthase Is Involved in Follicular Development via the PI3K/AKT/FoxO3a Pathway in Neonatal and Immature Rats

Study on the effects and mechanisms of Wenzhong Bushen Formula in improving ovarian reserve decline in mice based on network pharmacology

ETHNOPHARMACOLOGICAL RELEVANCE

The Wenzhong Bushen Formula (WZBSF) is a traditional Chinese medicine empirical formula known for its effects in tonifying qi, strengthening the spleen, warming the kidneys, promoting yang, regulating blood circulation, and balancing menstruation. Clinical evidence has demonstrated its significant efficacy in treating Diminished Ovarian Reserve (DOR) by improving ovarian reserves. However, the specific pharmacological mechanisms of WZBSF remain unclear.

AIM OF THE STUDY

This study aims to investigate the mechanisms by which WZBSF improves ovarian reserve decline through network pharmacology and animal experiments.

METHODS AND MATERIALS

WZBSF was analyzed using a dual UPLC-MS/MS and GC-MS platform. Effective components and targets of WZBSF were obtained from the TCMSP database and standardized using UniProt. Disease targets were collected from GeneCard, OMIM, PHARMGKB, and DisGeNET databases, with cross-referencing between the two sets of targets. A PPI protein interaction network was constructed using Cytoscape3.9.1 and STRING database, followed by KEGG and GO enrichment analysis using the Metascape database. Finally, an ovarian reserve decline model was established in mice, different doses of WZBSF were administered, and experimental validation was conducted through serum hormone detection, H&E staining, immunofluorescence (IF), immunohistochemistry (IHC), and Western blot analysis (WB).

RESULTS

WZBSF shares 145 common targets with ovarian reserve decline. GO enrichment analysis revealed involvement in biological processes such as response to hormone stimulation and phosphatase binding, while KEGG analysis implicated pathways including the PI3K-AKT signaling pathway and FoxO signaling pathway. In mice with ovarian reserve decline, WZBSF restored weight gain rate, increased ovarian index, normalized estrous cycles, reversed serum hormone imbalances, restored various follicle counts, and improved ovarian morphology. Additionally, WZBSF reduced p-AKT and p-FOXO3a levels, preventing excessive activation of primordial follicles and maintaining ovarian reserve.

CONCLUSION

WZBSF can ameliorate cyclophosphamide and busulfan-induced ovarian reserve decline, and its mechanism may be associated with the inhibition of the PI3K/AKT/FOXO3a signaling pathway.

Uncovering Novel Protein Partners of Inducible Nitric Oxide Synthase in Human Testis

Peroxidative damage to human spermatozoa has been shown to be the primary cause of male infertility. The possible role of nitric oxide (NO) in affecting sperm motility, capacitation, and acrosome reaction has been reported, too. The overproduction of NO by the enzyme inducible nitric oxide synthase (iNOS) could be responsible as it has been implicated in the pathogenesis of many diseases. There have been many studies on regulating iNOS function in various tissues, especially by protein-protein interaction; however, no study has looked for iNOS-interacting proteins in the human testis. Here, we have reported the identification of two proteins that interact with iNOS. We initially undertook a popular yeast two-hybrid assay to screen a human testis cDNA library in yeast using an iNOS-peptide fragment (amino acids 181-335) as bait. We verified our data using the mammalian chemiluminescent co-IP method; first, employing the same peptide and, then, a full-length protein co-expressed in HEK293 cells in addition to the candidate protein. In both cases, these two protein partners of iNOS were revealed: (a) sperm acrosome-associated 7 protein and (b) retinoblastoma tumor-suppressor binding protein.

Evaluation of Oxidative and Nitrosative Stress Markers Related To Inflammation in The Cumulus Cells and Follicular Fluid of Women Undergoing Intracytoplasmic Sperm Injection: A Prospective Study

BACKGROUND

Oxidative/nitrosative stress in the oocyte microenvironment could have an impact on intracytoplasmic sperm injection (ICSI) outcomes. The presence of reactive oxygen species (ROS) and reactive nitrogen species (RNS) can stimulate the secretion of pro-inflammatory cytokines, leading to chronic inflammation and potentially affecting embryo as well as oocyte quality. This study aimed to examine the relationship of lipid peroxidation [measured by the malondialdehyde (MDA) assay] with protein carbonyl [measured by the 2,4 dinitrophenylhydrazine (DNPH) assay] levels in cumulus cells (CCs), as well as nitric oxide (NO), peroxynitrite (ONOO-), and C-reactive protein (CRP) levels in follicular fluid (FF). The potential relationship of these levels with ICSI outcome was also evaluated.

MATERIALS AND METHODS

In this prospective study, 63 FF samples and their corresponding CCs were collected for ICSI procedures. Spectrophotometry was used to assess levels of DNPH, MDA, NO, and ONOO-. CRP levels were evaluated using an immunoturbidimetric assay.

RESULTS

The patients under 37 years with normal ovarian reserve had significantly lower levels of MDA, DNPH, NO, ONOO-, and CRP compared to those over 37 years. Additionally, we observed higher levels of MDA, DNPH, NO, ONOO-, and CRP in the group with an oocyte maturity rate of less than 60%. No significant difference was observed between the DNPH levels and factors such as infertility duration, embryo quality, pregnancy, or the number of retrieved oocytes. A higher level of MDA, NO, ONOO-, and CRP was found to be significantly related to the lower number of retrieved oocytes, longer periods of infertility, poor embryo quality, and negative pregnancy outcomes.

CONCLUSION

Oxidative/nitrosative stress, linking to inflammation in the oocyte microenvironment, can be considered as a potentially useful biomarker for assessing the development and competence of oocytes and embryos and predicting ICSI outcomes.

Uterodilation effect of unripe fruit extract of Crataegus azarolus var. aronia L. on rat uterine smooth muscles

Crataegus azarolus var. aronia L. (C. aronia) is one of the most important medicinal plants used widely in folk medicine for the prevention of several diseases due to its content of several bioactive compounds like phenolic acid, aromatic amines, proanthocyanidins and flavonoids. This study investigated the uterodilation effect of methanol extract (ME) of C. aronia unripe fruit on the uterine smooth muscle in rats. The mechanism of action underlying the plant's extract was also screened. The unripe fruits were cleaned and extracted in methanol. The extract (1.9-4 mg/ml) was tested on rat uterine relaxation in calcium-free Kreb's solution and potassium chloride-induced uterine contraction. The plant extract was also studied in the presence of antagonists in separate experiments to determine the role of various ion channels and hyperpolarizing agents. The plant extract showed an uterodilation effect on the uterus, in which the ME produced a considerable relaxant effect. The results confirmed that the induced dilation was mediated mainly by the nitric oxide pathway and the activation of potassium channels with a limited role of the prostaglandin pathway and calcium channel activation. This in-vitro study provides the first scientific evidence of the claimed effect of C. aronia on uterine relaxation.

A review of nitric oxide and oxidative stress in typical ovulatory women and in the pathogenesis of ovulatory dysfunction in PCOS

Polycystic ovary syndrome (PCOS) is a heterogeneous functional endocrine disorder associated with a low-grade, chronic inflammatory state. Patients with PCOS present an increased risk of metabolic comorbidities and often menstrual dysregulation and infertility due to anovulation and/or poor oocyte quality. Multiple mechanisms including oxidative stress and low-grade inflammation are believed to be responsible for oocyte deterioration; however, the influence of nitric oxide (NO) insufficiency in oocyte quality and ovulatory dysfunction in PCOS is still a matter for debate. Higher production of superoxide (O2•-) mediated DNA damage and impaired antioxidant defense have been implicated as contributory factors for the development of PCOS, with reported alteration in superoxide dismutase (SOD) function, an imbalanced zinc/copper ratio, and increased catalase activity. These events may result in decreased hydrogen peroxide (H2O2) accumulation with increased lipid peroxidation events. A decrease in NO, potentially due to increased activity of NO synthase (NOS) inhibitors such as asymmetric dimethylarginine (ADMA), and imbalance in the distribution of reactive oxygen species (ROS), such as decreased H2O2 and increased O2•-, may offset the physiological processes surrounding follicular development, oocyte maturation, and ovulation contributing to the reproductive dysfunction in patients with PCOS. Thus, this proposal aims to evaluate the specific roles of NO, oxidative stress, ROS, and enzymatic and nonenzymatic elements in the pathogenesis of PCOS ovarian dysfunction, including oligo- anovulation and oocyte quality, with the intent to inspire better application of therapeutic options. The authors believe more consideration into the specific roles of oxidative stress, ROS, and enzymatic and nonenzymatic elements may allow for a more thorough understanding of PCOS. Future efforts elaborating on the role of NO in the preoptic nucleus to determine its influence on GnRH firing and follicle-stimulating hormone/Luteinizing hormone (FSH/LH) production with ovulation would be of benefit in PCOS. Consequently, treatment with an ADMA inhibitor or NO donor may prove beneficial to PCOS patients experiencing reproductive dysfunction and infertility.

Nitric oxide synthase and its function in animal reproduction: an update

Nitric oxide (NO), a free radical labile gas, is involved in the regulation of various biological functions and physiological processes during animal reproduction. Recently, increasing evidence suggests that the biological role and chemical fate of NO is dependent on dynamic regulation of its biosynthetic enzyme, three distinct nitric oxide synthase (NOS) according to their structure, location and function. The impact of NOS isoforms on reproductive functions need to be timely elucidated. Here, we focus on and the basic background and latest studies on the development, structure, importance inhibitor, location pattern, complex functions. Moreover, we summarize the exactly mechanisms which involved some cell signal pathways in the regulation of NOS with cellular and molecular level in the animal reproduction. Therefore, this growing research area provides the new insight into the important role of NOS male and female reproduction system. It also provides the treatment evidence on targeting NOS of reproductive regulation and diseases.

NO-Dependent Mechanisms of p53 Expression and Cell Death in Rat’s Dorsal Root Ganglia after Sciatic-Nerve Transection

Peripheral-nerve injury is a frequent cause of disability. Presently, no clinically effective neuroprotectors have been found. We have studied the NO-dependent expression of p53 in the neurons and glial cells of the dorsal root ganglia (DRG) of a rat’s spinal cord, as well as the role of NO in the death of these cells under the conditions of axonal stress, using sciatic-nerve axotomy as a model. It was found out that axotomy led to the nuclear–cytoplasmic redistribution of p53 in neurons, 24 h after trauma. The NO donor led to a considerable increase in the level of p53 in nuclei and, to a smaller degree, in the cytoplasm of neurons and karyoplasm of glial cells 4 and 24 h after axotomy. Application of a selective inhibitor of inducible NO-synthase (iNOS) provided the opposite effect. Introduction of the NO donor resulted in a significant increase in cell death in the injured ipsilateral DRG, 24 h and 7 days after trauma. The selective inhibitor of iNOS demonstrated a neuroprotective effect. Axotomy was shown to upregulate the iNOS in nuclei and cytoplasm of DRG cells. The NO-dependent expression of p53, which is particularly achieved through iNOS activation, is believed to be a putative signaling mechanism of neural and glial-cell death after axotomy.

Roles of Nitric Oxide in the Regulation of Reproduction: A Review

Nitric oxide (NO) has attracted significant attention as a stellar molecule. Presently, the study of NO has penetrated every field of life science, and NO is widely distributed in various tissues and organs. This review demonstrates the importance of NO in both male and female reproductive processes in numerous ways, such as in neuromodulation, follicular and oocyte maturation, ovulation, corpus luteum degeneration, fertilization, implantation, pregnancy maintenance, labor and menstrual cycle regulation, spermatogenesis, sperm maturation, and reproduction. However, the mechanism of action of some NO is still unknown, and understanding its mechanism may contribute to the clinical treatment of some reproductive diseases.

Intergenerational high-fat diet impairs ovarian follicular development in rodents: a systematic review and meta-analysis

CONTEXT

Excessive consumption of high-fat diets has increased in the population over time and is harmful to female fertility.

OBJECTIVE

To investigate and discuss the effects of a high-fat diet on ovarian follicles in rodents.

DATA SOURCE

A systematic literature search of PubMed, EMBASE, Web of Science, and SCOPUS was carried out.

DATA EXTRACTION

Study characteristics, including study design, population, intervention, outcome, and risk of bias were analyzed.

DATA ANALYSIS

Twenty-two articles were included in a systematic review. Given the availability of studies, a quantitative meta-analysis included 12 studies that were performed for outcomes. There was a decrease in primordial follicles in female rodents that received a high-fat diet compared with the standard diet group. The offspring of mothers exposed to a high-fat diet showed an increased number of cystic follicles and a decreased number of secondary follicles and antral follicles, compared with the control diet group. Therefore, these high-fat diet-induced follicular alterations might impair the fertility of dams and their female newborns.

CONCLUSION

The consumption of a high-fat diet causes damage to ovarian follicular development, and this commitment will persist in the next generation.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no. CRD42019133865.

Ameliorative role of inducible nitric oxide synthase inhibitors against sodium arsenite-induced renal and hepatic dysfunction in rats

Arsenic exposure causes immense health distress by increasing risk of cardiovascular abnormalities, diabetes mellitus, neurotoxicity, and nephrotoxicity. The present study explored the role of inducible nitric oxide synthase (iNOS) inhibitors against sodium arsenite-induced renal and hepatic dysfunction in rats. Female Sprague Dawley rats were subjected to arsenic toxicity by administering sodium arsenite (5 mg/kg/day, oral) for 4 weeks. The iNOS inhibitors, S-methylisothiourea (10 mg/kg, i.p.) and aminoguanidine (100 mg/kg, i.p.) were given one hour before sodium arsenite administration in rats for 4 weeks. Sodium arsenite led rise in serum creatinine, urea, uric acid, electrolytes (potassium, fractional excretion of sodium), microproteinuria, and decreased creatinine clearance (p < 0.001) indicated renal dysfunction in rats. Arsenic-intoxication resulted in significant oxidative stress in rat kidneys, which was measured in terms of increase in lipid peroxides, superoxide anion generation and decrease in reduced glutathione (p < 0.001) levels. A threefold increase in renal hydroxyproline level in arsenic intoxicated rats indicated fibrosis. Hematoxylin-eosin staining indicated tubular damage, whereas picrosirius red staining highlighted collagen deposition in rat kidneys. S-methylisothiourea and aminoguanidine improved renal function and attenuated arsenic led renal oxidative stress, fibrosis, and decreased the kidney injury score. Additionally, arsenite-intoxication resulted in significant rise in hepatic parameters (serum aspartate aminotransferase, alanine transferase, alkaline phosphatase, and bilirubin (p < 0.001) along with multi-fold increase in oxidative stress, fibrosis and liver injury score in rats, which was significantly (p < 0.001) attenuated by concurrent administration of iNOS inhibitors). Hence, it is concluded that iNOS inhibitors attenuate sodium arsenite-induced renal and hepatic dysfunction in rats.

Enrichment analyses of diseases and pathways associated with precocious puberty using PrecocityDB

Precocious puberty (PP) is an important endocrine disorder affecting children globally. Several genes, SNPs and comorbidities are reported to be associated with PP; however, this data is scattered across scientific literature and has not been systematically collated and analysed. In this study, we present PrecocityDB as the first manually curated online database on genes and their ontology terms, SNPs, and pathways associated with PP. A tool for visualizing SNP coordinates and allelic variation on each chromosome, for genes associated with PP is also incorporated in PrecocityDB. Pathway enrichment analysis of PP-associated genes revealed that endocrine and cancer-related pathways are highly enriched. Disease enrichment analysis indicated that individuals with PP seem to be highly likely to suffer from reproductive and metabolic disorders such as PCOS, hypogonadism, and insulin resistance. PrecocityDB is a useful resource for identification of comorbid conditions and disease risks due to shared genes in PP. PrecocityDB is freely accessible at http://www.precocity.bicnirrh.res.in . The database source code and content can be downloaded through GitHub ( https://github.com/bic-nirrh/precocity ).

The endothelial nitric oxide synthase/cyclic guanosine monophosphate/protein kinase G pathway activates primordial follicles

In mammals, the well-organized activation of quiescent primordial follicles is pivotal for female reproductive reserve. In the present study, we examined the mechanisms underlying primordial follicle activation in mice. We found that endothelial nitric oxide synthase (eNOS) and its downstream effectors, cyclic guanosine monophosphate (cGMP) and cGMP-dependent protein kinase G (PKG), were expressed in pre-granulosa cells and promoted primordial follicle activation, oocyte growth and granulosa cell proliferation in neonatal ovaries. Mammalian target of rapamycin (mTOR) colocalized with PKG in pre-granulosa cells and was essential for eNOS/cGMP/PKG pathway-induced primordial follicle activation. The eNOS/cGMP/PKG pathway was found to stabilize mTOR protein. The mRNA levels of F-box and WD repeat domain containing 7 (FBXW7), an E3 ubiquitin ligase, correlated negatively with mTOR protein levels in neonatal ovaries. FBXW7 bound to and destabilized mTOR protein in pre-granulosa cells in a ubiquitin/proteasome-dependent manner. However, agonists of the eNOS/cGMP/PKG pathway reduced FBXW7 mRNA levels. FBXW7 overexpression suppressed primordial follicle activation and prevented the eNOS/cGMP/PKG pathway from activating primordial follicles and stabilizing mTOR protein. These findings demonstrate that the eNOS/cGMP/PKG pathway activates primordial follicles by suppressing FBXW7-induced ubiquitination of mTOR in mice.

Expression Regulation and Physiological Role of Transcription Factor FOXO3a During Ovarian Follicular Development

In mammals, developing ovarian follicles transform from primordial follicles to primary follicles, secondary follicles, and mature follicles, accompanied by changes in follicular secretory functions. FoxO3a is a member of the forkhead transcription factor family (FoxO), which plays an important role in the cell cycle, DNA damage repair, apoptosis, oxidative stress, and energy metabolism. Recent studies have shown that FOXO3a is involved in the physiological regulation of follicular development and pathological progression of related ovarian diseases, which will provide useful concepts and strategies for retarding ovarian aging, prolonging the ovarian life span, and treating ovarian diseases. Therefore, the regulation of FOXO3a expression, as well as the physiological contribution during ovarian follicular development are detailed in this paper, presenting an important reference for the further study of ovarian biology.