Ginsenosides stimulated the proliferation of mouse spermatogonia involving activation of protein kinase C

Multi-omics and network pharmacology approaches reveal Gui-Ling-Ji alleviates oligoasthenoteratozoospermia by regulating arachidonic acid pathway

BACKGROUND

Gui-Ling-Ji (GLJ) described in the ancient medical book 'Yunji Qijian' is a traditional Chinese medicine formula used to improve male fertility. It is now available for the treatment of oligoasthenoteratozoospermia (OAT). However, the active ingredients and mechanism of GLJ are not clear.

PURPOSE

The aim of this study was to clarify the active ingredients and mechanism of GLJ in OAT.

METHODS

Firstly, the cyclophosphamide-induced OAT rat model was established to evaluate the efficacy of GLJ. Secondly, serum/urine-based metabolomics and lipidomics and tissue-based transcriptomics were performed to discover the differential metabolites and genes in rats. Furthermore, network pharmacology was constructed to explore the associated mechanisms based on the results of multi-omics analysis. Finally, cellular experiment on testicular mesenchymal stromal cells (TM3) was used to validate the active ingredients and the key metabolic pathway.

RESULTS

Rats were administered GLJ by gavage every day for 3 weeks. Testicular damage and weight loss caused by cyclophosphamide were restored in rats, the sperm count and motility were improved, and levels of luteinizing hormone (LH), follicle-stimulating hormone (FSH) and testosterone (T) secretion were also elevated. Compared to the metabolites of OAT rats, 51 and 37 differential metabolites regulated by GLJ were identified from serum and urine respectively, 54 lipid differential metabolites regulated by GLJ were identified by lipidomics. At the same time, 23 of the 258 differential genes were found to be regulated by OAT rats and then reverse-regulated by GLJ. Network pharmacology has identified 13 pathways (Steroid hormone biosynthesis, Taurine and hypotaurine metabolism, Primary bile acid biosynthesis, Linoleic acid metabolism, Retinol metabolism, Glycerophospholipid metabolism, Ether lipid metabolism, Sphingolipid metabolism, Arachidonic acid metabolism, Glutathione metabolism, Arginine biosynthesis, Arginine and proline metabolism, D-Arginine and D-ornithine metabolism), four metabolites (arachidonic acid, oestrone sulphate, phosphatidylglycerol choline and sphingomyelin) and 15 targets (ABCB11, ALDH18A1, CCL3, CD244, CIITA, CYP2C8, DLL1, ITGA4, ESR1, AR, ABCB1, ABCC1, ALB, PLA2G1B and NOS2). GLJ, psoralen, isopsoralen, liquiritin, isoliquiritin, liquiritigenin, and ginsenoside Ro could significantly promote T secretion from TM3 cells. Additionally, arachidonic acid metabolism particularly the cyclooxygenase pathway, is closely related to the promotion of testosterone secretion by GLJ in TM3.

CONCLUSION

GLJ has a therapeutic efficacy in cyclophosphamide-induced OAT rats, which can modulate the disorders of lipid metabolism and amino acid metabolism. Arachidonic acid metabolism may be a key pathway, and six prototype compounds are potential key active ingredients for GLJ.

Panax ginseng Extract Improves Follicular Development after Mouse Preantral Follicle 3D Culture

Objective

Panax ginseng is a popular traditional herb that has been used in complementary and alternative medicine in eastern Asia, and it possesses pharmacologically active compounds like ginsenosides (GSs). This study aimed to investigate the impact of Panax ginseng extract (PGE) at different concentrations on in vitro follicular function and development in a three-dimensional (3D) culture system fabricated using sodium alginate after 12 days of culture.

Materials and Methods

In this experimental study, preantral follicles (n=661) were mechanically isolated from the ovaries of 14-day-old female NMRI mice using 29-gauge insulin syringes. Follicles were individually capsulated within sodium alginate, and divided into four groups including control and experimental groups 1, 2, and 3. Then, they were cultured for 12 days in the medium supplemented with different concentrations of PGE (0, 50, 100, and 500 µg/ mL, for control groups and groups 1, 2 and 3, respectively). At the end of the culture period, the mean diameter and maturation of follicles, follicular steroid production, mRNA expression level of proliferating cell nuclear antigen (PCNA) and follicle stimulating hormone receptor (FSH-R), and reactive oxygen species (ROS) levels in collected metaphase-II (MII) oocytes were determined.

Results

The mean diameter of follicles in group 2 was significantly increased as compared to other groups (P<0.001). The percentages of the survival and maturation rate and levels of secreted hormones were higher in group 2 than the other groups (P<0.05). Follicles cultured in the presence of PGE 100 µg/mL had higher levels of proliferation cell nuclear antigen (PCNA) and follicle stimulating hormone receptor (FSH-R) mRNA expression in comparison to other groups (P<0.05). Moreover, oocytes collected from groups 2 and 3 had lower levels of ROS as compared to other groups (P<0.05).

Conclusion

Our results suggest that PGE at the concentration of 100 µg/mL induces higher follicular function and development in the 3D culture system.

Alleviative effect of quercetin on germ cells intoxicated by 3-methyl-4-nitrophenol from diesel exhaust particles

As a component of diesel exhaust particles, 3-methyl-4-nitrophenol (4-nitro-m-cresol, PNMC) is also a metabolite of the insecticide fenitrothion and imposes hazardous effects on human health. In the present study, the alleviative effect of a common antioxidant flavonoid quercetin on mouse germ cells intoxicated by PNMC was investigated. Results showed that a single intraperitoneal injection of PNMC at 100 mg/kg induced severe testicular damage after one week. PNMC-treated mice showed a significant loss of germ cells (approximate 40% loss of round germ cells). PNMC caused an increase of hydroxyl radical and hydrogen peroxide production and lipid peroxidation, as well as a decrease in glutathione level, superoxide dismutase and glutathione peroxidase activities. Furthermore, treatment of PNMC increased expression of the pro-apoptotic protein Bax and decreased expression of the anti-apoptotic protein Bcl-XL in germ cells. In addition, testicular caspase-3 activity was significantly up-regulated and germ cell apoptosis was significantly increased in the PNMC-treated mice. In contrast, combined administration of quercetin at 75 mg/kg significantly attenuated PNMC-induced testicular toxicity. These results indicate that the antioxidant quercetin displays a remarkable protective effect on PNMC-induced oxidative damage in mouse testes and may represent an efficient supplement to attenuate reproductive toxicity by environmental toxicants to ensure healthy sperm production.

Follicle-stimulating hormone promotes proliferation of cultured chicken ovarian germ cells through protein kinases A and C activation

The study was conducted to investigate the effects of follicle-stimulating hormone (FSH) on embryonic chicken ovarian germ cell proliferation and its possible involvements of protein kinases A (PKA) and C (PKC) pathways. Ovarian cells were treated with FSH alone or in the presence of forskolin (FRSK), PKA inhibitor (H(89)), PKC activator (PMA) or inhibitor (H(7)). The germ cell number was counted from micropictures. The immunocytochemistry of proliferating cell nuclear antigen (PCNA) was applied to identify the proliferating cells. The germ cell labeling index (LI) was determined for cell proliferation. The FSH treatment increased the germ cell number, and this stimulating effect was enhanced by FRSK or PMA, but inhibited by H(89) or H(7) in a dose-dependent manner. Moreover, the PCNA-LI showed parallel changes with germ cell numbers. This study suggests that FSH may stimulate proliferation of cultured chicken ovarian germ cells by activation of both the PKA and PKC signaling pathways.

Ginsenosides promote proliferation of granulosa cells from chicken prehierarchical follicles through PKC activation and up-regulated cyclin gene expression

The effect of GS (ginsenosides) on proliferation of chicken GCs (granulosa cells) from prehierarchical SYF (small yellow follicles) was evaluated, and involvement of the PKC (protein kinase C) signalling pathway as well as mRNA expression of cyclins and CDK (cyclin-dependent kinase) were investigated. Whole SYF or GCs isolated from SYF were cultured in Medium 199 supplemented with 0.5% FCS (fetal calf serum). After 16 h, the cells were challenged with GS alone or in combination with PKC inhibitor H7 or activator PMA (phorbol 12-myristate 13-acetate) for 24 h in serum-free medium. Results showed that in both whole follicles and pure GCs monolayer culture system, GS (0.1-10 microg/ml) significantly increased the number of GCs in SYF in a dose-dependent manner, and this stimulatory effect was inhibited by H7, but enhanced by PMA. Meanwhile, the PCNA-LI (proliferating cell nuclear antigen labelling index) of GCs displayed similar changes with the cell number. Mechanism of GS action was further evaluated in cultured GCs separated from SYF. Western blot analysis showed that 10 microg/ml GS increased PKC translocation from cytoplasm to the plasma membrane of the GCs to become the active state. This effect was blocked by H7. Furthermore, GS up-regulated the expression of cyclin D1/CDK6 and cyclin E/CDK2 mRNAs in GCs; however, inhibition of PKC with H7 attenuated this stimulatory effect. These results indicated that GS could stimulate proliferation of chicken GCs through activated PKC-involved up-regulation of cyclin D1/CDK6 and cyclin E/CDK2 genes, subsequently promoting development of the chicken prehierarchical follicles.

Effect of prostaglandin on luteinizing hormone-stimulated proliferation of theca externa cells from chicken prehierarchical follicles

The effect of prostaglandin (PG) on proliferation of chicken theca externa cells from prehierarchical small yellow follicles (SYF) was evaluated and involved signaling pathways as well as mRNA expression of cAMP response element binding protein (CREB1), cyclins (CCND1 and CCNE1) and cyclin-dependent kinases (CDKs) were investigated. Results showed that PGE(1) (1-100 ng/ml) manifested a similar proliferating effect as LH on theca externa cells, and this stimulating effect was restrained by the prostaglandin receptor antagonist SC19220 at 10(-7) to 10(-5)M. Moreover, prostaglandin synthase inhibitor indomethacin (10(-7) to 10(-5)M) suppressed LH-induced increase in the cell number. In addition, PGE(1)-stimulated cell proliferation was also predominantly hindered by H(89) (PKA inhibitor) instead of H(7) (PKC inhibitor). Meanwhile, BrdU incorporation experiment displayed similar changes with the cell number. Furthermore, H(89), SC19220 and indomethacin abolished the PGE(1)-stimulated increase in the expression of CREB1, CCND1/CDK6 and CCNE1/CDK2 mRNAs, indicating that cAMP/PKA/CREB1 signaling cascade was involved in PGE(1)-stimulated DNA synthesis. In conclusion, PG could promote proliferation of theca externa cells from prehierarchical follicles through changes in cyclin D1/CDK6, cyclin E1/CDK2 and CREB1 mRNA expression via cAMP/PKA and CREB1 signaling cascade. These results suggest that PG may promote development of chicken prehierarchical follicles and is related to dominant follicle selection in laying hens.

Selection and mutation on microRNA target sequences during rice evolution

Background

MicroRNAs (miRNAs) posttranscriptionally down-regulate gene expression by binding target mRNAs. Analysis of the evolution of miRNA binding sites is helpful in understanding the co-evolution between miRNAs and their targets. To understand this process in plants a comparative analysis of miRNA-targeted duplicated gene pairs derived from a well-documented whole genome duplication (WGD) event in combination with a population genetics study of six experimentally validated miRNA binding sites in rice (O. sativa) was carried out.

Results

Of the 1,331 pairs of duplicate genes from the WGD, 41 genes (29 pairs) were computationally predicted to be miRNA targets. Sequence substitution analysis indicated that the synonymous substitution rate was significantly lower in the miRNA binding sites than their 5' and 3' flanking regions. Of the 29 duplicated gene pairs, 17 have only one paralog been targeted by a miRNA. This could be due to either gain of a miRNA binding site after the WGD or because one of the duplicated genes has escaped from being a miRNA target after the WGD (loss of miRNA binding site). These possibilities were distinguished by separating miRNAs conserved in both dicots and monocot plants from rice-specific miRNAs and by phylogenetic analysis of miRNA target gene families. The gain/loss rate of miRNA binding sites was estimated to be 3.0 × 10^-9 gain/loss per year. Most (70.6%) of the gains/losses were due to nucleotide mutation. By analysis of cultivated (O. sativa; n = 30) and wild (O. rufipogon; n = 15) rice populations, no segregating site was observed in six miRNA binding sites whereas 0.12–0.20 SNPs per 21-nt or 1.53–1.80 × 10^-3 of the average pairwise nucleotide diversity (π) were found in their flanking regions.

Conclusion

Both molecular evolution and population genetics support the hypothesis that conservation of miRNA binding sites is maintained by purifying selection through elimination of deleterious alleles. Nucleotide mutations play a major role in the gain/loss of miRNA binding sites during evolution.