High-throughput Exploration of the Network Dependent on AKT1 in Mouse Ovarian Granulosa Cells

Molecular crosstalk between insulin-like growth factors and follicle-stimulating hormone in the regulation of granulosa cell function

Background

The last phase of folliculogenesis is driven by follicle-stimulating hormone (FSH) and locally produced insulin-like growth factors (IGFs), both essential for forming preovulatory follicles.

Methods

This review discusses the molecular crosstalk of the FSH and IGF signaling pathways in regulating follicular granulosa cells (GCs) during the antral-to-preovulatory phase.

Main findings

IGFs were considered co-gonadotropins since they amplify FSH actions in GCs. However, this view is not compatible with data showing that FSH requires IGFs to stimulate GCs, that FSH renders GCs sensitive to IGFs, and that FSH signaling interacts with factors downstream of AKT to stimulate GCs. New evidence suggests that FSH and IGF signaling pathways intersect at several levels to regulate gene expression and GC function.

Conclusion

FSH and locally produced IGFs form a positive feedback loop essential for preovulatory follicle formation in all species. Understanding the mechanisms by which FSH and IGFs interact to control GC function will help design new interventions to optimize follicle maturation, perfect treatment of ovulatory defects, improve in vitro fertilization, and develop new contraceptive approaches.

Large-scale DNA demethylation occurs in proliferating ovarian granulosa cells during mouse follicular development

During ovarian follicular development, granulosa cells proliferate and progressively differentiate to support oocyte maturation and ovulation. To determine the underlying links between proliferation and differentiation in granulosa cells, we determined changes in 1) the expression of genes regulating DNA methylation and 2) DNA methylation patterns, histone acetylation levels and genomic DNA structure. In response to equine chorionic gonadotropin (eCG), granulosa cell proliferation increased, DNA methyltransferase (DNMT1) significantly decreased and Tet methylcytosine dioxygenase 2 (TET2) significantly increased in S-phase granulosa cells. Comprehensive MeDIP-seq analyses documented that eCG treatment decreased methylation of promoter regions in approximately 40% of the genes in granulosa cells. The expression of specific demethylated genes was significantly increased in association with specific histone modifications and changes in DNA structure. These epigenetic processes were suppressed by a cell cycle inhibitor. Based on these results, we propose that the timing of sequential epigenetic events is essential for progressive, stepwise changes in granulosa cell differentiation.

Zihuai recipe alleviates cyclophosphamide-induced diminished ovarian reserve via suppressing PI3K/AKT-mediated apoptosis

ETHNOPHARMACOLOGICAL RELEVANCE

Zihuai recipe (ZHR), a Chinese herbal prescription, is widely used for the clinical treatment of Diminished ovarian reserve (DOR) infertility. However, little is known regarding its underlying mechanisms of DOR treatment.

AIM OF THE STUDY

This study aimed to investigate the beneficial effects of ZHR on the treatment of DOR and to reveal the underlying mechanisms.

MATERIALS AND METHODS

Sixty female 8-week-old Sprague-Dawley rats were randomly divided into the following six groups (n=10 per group): control, DOR, low-dose(2.7 g/kg/day) ZHR (L-ZHR), medium-dose(5.4 g/kg/day), ZHR (M-ZHR), high-dose(10.8 g/kg/day) ZHR (H-ZHR), and hormone replacement therapy (HRT) treatment groups. The DOR model was established in all the groups, except the control group, by a single intraperitoneal injection of 90 mg/kg cyclophosphamide. After the induction of the DOR model, rats were weighed and administered either the relevant dose of ZHR or an equal volume of saline solution (in the control and DOR groups). Rats in the HRT group received estradiol valerate tablets (0.16 mg/kg/day), and with medroxyprogesterone acetate tablets (0.86 mg/kg/day) added on day 4. After 32 days of treatment, the rats were euthanized and the ovaries were collected for sampling. Ovarian morphology was observed by hematoxylin and eosin staining and the number of follicles was counted under a microscope. The serum levels of anti-Müllerian hormone (AMH), gonadotropin-releasing hormone (GnRH), follicle-stimulating hormone (FSH), luteinizing hormone (LH), and estradiol (E2) were quantified by ELISA. A TUNEL assay was used to analyze the level of apoptosis of the ovarian cells. The protein expressions of p-PI3K, p-AKT, PI3K, AKT, cleaved caspase-3, BAX, and Bcl-2 were measured by western blotting and immunohistochemistry. Data analysis was performed with SPSS 20.0 software.

RESULTS

ZHR administration increased the ovarian index and the serum levels of AMH, GnRH, and E2, while lowering those of FSH and LH. ZHR treatment also increased the number of primordial, primary, secondary, and antral follicles, as well as the number of corpora lutea, but decreased the number of atretic follicles. Furthermore, ZHR administration decreased the percentage of TUNEL-positive ovarian cells. After treatment with ZHR, the protein expression levels of p-PI3K/PI3K, p-AKT/AKT, cleaved caspase-3 and BAX were decreased, whereas the level of Bcl-2 was increased.

CONCLUSIONS

ZHR improved the ovarian reserve in CTX-induced DOR rats. The mechanisms of ZHR on DOR may be mediated through the regulation of gonadal hormones of the hypothalamic-pituitary-ovarian axis (HPOA), and the inhibition of PI3K/AKT-mediated apoptosis in granulosa cells.

Small RNA sequencing reveals distinct nuclear microRNAs in pig granulosa cells during ovarian follicle growth

Nuclear small RNAs have emerged as an important subset of non-coding RNA species that are capable of regulating gene expression. A type of small RNA, microRNA (miRNA) have been shown to regulate development of the ovarian follicle via canonical targeting and translational repression. Little has been done to study these molecules at a subcellular level. Using cell fractionation and high throughput sequencing, we surveyed cytoplasmic and nuclear small RNA found in the granulosa cells of the pig ovarian antral preovulatory follicle. Bioinformatics analysis revealed a diverse network of small RNA that differ in their subcellular distribution and implied function. We identified predicted genomic DNA binding sites for nucleus-enriched miRNAs that may potentially be involved in transcriptional regulation. The small nucleolar RNA (snoRNA) SNORA73, known to be involved in steroid synthesis, was also found to be highly enriched in the cytoplasm, suggesting a role for snoRNA species in ovarian function. Taken together, these data provide an important resource to study the small RNAome in ovarian follicles and how they may impact fertility.

Network Pharmacology-Based Prediction and Verification of the Active Ingredients and Potential Targets of Zuojinwan for Treating Colorectal Cancer

Background

Zuojinwan (ZJW), a famous Chinese medicine formula, has been widely used to treat colorectal cancer (CRC). However, its bioactive compounds, potential targets, and molecular mechanism remain largely elusive.

Aim

A network pharmacology-based strategy combined with molecular docking studies and in vitro validation were employed to investigate bioactive compounds, potential targets, and molecular mechanism of ZJW against CRC.

Materials and Methods

Bioactive compounds and potential targets of ZJW, as well as related genes of CRC, were acquired from public databases. Important ingredients, potential targets, and signaling pathways were determined through bioinformatics analysis, including protein-protein interaction (PPI), the Gene Ontology (GO), and the Kyoto Encyclopedia of Genes and Genomes (KEGG). Subsequently, molecular docking and cell experiments were performed to further verify the findings.

Results

A total of 36 bioactive ingredients of ZJW and 163 gene targets of ZJW were identified. The network analysis revealed that quercetin, baicalein, wogonin, beta-sitosterol, and isorhamnetin may be candidate agents. The AKT1, JUN, CDKN1A, BCL2L1, and NCOA1 could become potential drug targets. The KEGG indicated that PI3K-AKT signaling pathway may play an important role in the effect of ZJW against CRC. Molecular docking suggested that quercetin, baicalein, and wogonin combined well with AKT1 and JUN. The in vitro experiment showed that quercetin, the most important ingredient of ZJW, could induce apoptosis of HCT116 cells through PI3K-Akt signaling pathway. This finding was congruent with the prediction obtained through the network pharmacology approach.

Conclusion

This study comprehensively illuminated the active ingredients, potential targets, and molecular mechanism of ZJW against CRC. It also provided a promising approach to uncover the scientific basis and therapeutic mechanism of traditional Chinese medicine (TCM) formula treating for disease.

Genome-wide DNA copy number profiling and bioinformatics analysis of ovarian cancer reveals key genes and pathways associated with distinct invasive/migratory capabilities

Ovarian cancer (OC) metastasis presents major hurdles that must be overcome to improve patient outcomes. Recent studies have demonstrated copy number variations (CNVs) frequently contribute to alterations in oncogenic drivers. The present study used a CytoScan HD Array to analyse CNVs and loss of heterozygosity (LOH) in the entire genomes of 6 OC patients and human OC cell lines to determine the genetic target events leading to the distinct invasive/migratory capacities of OC. The results showed that LOH at Xq11.1 and Xp21.1 and gains at 8q21.13 were novel, specific CNVs. Ovarian cancer-related CNVs were then screened by bioinformatics analysis. In addition, transcription factors-target gene interactions were predicted with information from PASTAA analysis. As a result, six genes (i.e., GAB2, AKT1, EGFR, COL6A3, UGT1A1 and UGT1A8) were identified as strong candidates by integrating the above data with gene expression and clinical outcome data. In the transcriptional regulatory network, 4 known cancer-related transcription factors (TFs) interacted with 6 CNV-driven genes. The protein/DNA arrays revealed 3 of these 4 TFs as potential candidate gene-related transcription factors in OC. We then demonstrated that these six genes can serve as potential biomarkers for OC. Further studies are required to elucidate the pathogenesis of OC.

Conventional and unconventional interactions of the transcription factor FOXL2 uncovered by a proteome-wide analysis

Beyond the study of its transcriptional target genes, the identification of the various interactors of a transcription factor (TF) is crucial to understand its diverse cellular roles. We focused on FOXL2, a winged-helix forkhead TF important for ovarian development and maintenance. FOXL2 has been implicated in diverse cellular processes, including apoptosis, the control of cell cycle or the regulation of steroid hormone synthesis. To reliably identify partners of endogenous FOXL2, we performed a proteome-wide analysis using co-immunoprecipitation in the murine granulosa cell-derived AT29c and the pituitary-derived alpha-T3 cell lines, using three antibodies targeting different parts of the protein. Following a stringent selection of mass spectrometry data on the basis of identification reliability and protein enrichment, we identified a core set of 255 partners common to both cell lines. Their analysis showed that we could co-precipitate several complexes involved in mRNA processing, chromatin remodeling and DNA replication and repair. We further validated (direct and/or indirect) interactions with selected partners, suggesting an unexpected role for FOXL2 in those processes. Overall, this comprehensive analysis of the endogenous FOXL2 interactome sheds light on its numerous and diverse interactors and unconventional cellular roles.

PI3K-AKT Signaling Activation and Icariin: The Potential Effects on the Perimenopausal Depression-Like Rat Model

Icariin is a prenylated flavonol glycoside isolated from Epimedium herb, and has been shown to be its main bioactive component. Recently, the antidepressant-like mechanism of icariin has been increasingly evaluated and demonstrated. However, there are few studies that have focused on the involvement of the phosphatidylinositol 3-kinase (PI3K)/serine-threonine protein kinase (AKT) signaling in mediating the perimenopausal depression effects of icariin. Perimenopausal depression is a chronic recurrent disease that leads to an increased risk of suicide, and poses a significant risk to public health. The aim of the present study was to explore the effect of icariin on the expression of the PI3K-AKT pathway related to proteins in a rat model of perimenopausal depression. Eighty percent of the left ovary and the entire right ovary were removed from the model rats. A perimenopausal depression model was created through 18 days of chronic unpredictable stimulation, followed by the gavage administration of target drugs for 30 consecutive days. We found that icariin administered at various doses significantly improved the apparent symptoms in the model rats, increased the organ indices of the uterus, spleen, and thymus, and improved the pathological changes in the ovaries. Moreover, icariin administration elevated the serum levels of female hormone estradiol (E2), testosterone (T), and interleukin (IL)-2, decreased those of follicle stimulating hormone (FSH) and luteotropic hormone (LH), promoted the expression levels of estrogen receptor (ER) and ERα in the hypothalamus, and increased those of serotonin (5-HT), dopamine (DA), and noradrenaline (NA) in the brain homogenate. Furthermore, icariin elevated the expression levels of AKT, phosphorylation-akt (p-AKT), PI3K (110 kDa), PI3K (85 kDa), and B-cell lymphoma 2 (Bcl-2) in the ovaries, and inhibited those of Bax. These results show that icariin administration rebalanced the disordered sex hormones in perimenopausal depression rats, regulated the secretion of neurotransmitters in the brain, boosted immune function, and improved the perimenopausal syndrome. The mechanism of action may be related to the regulation of the expression of PI3K-AKT pathway-related proteins.