[Mechanism of protective effect of resveratrol on poor ovarian response in mice].

This study aims to investigate the therapeutic effects and potential mechanisms of resveratrol(Res) on poor ovarian response(POR) in mice. The common target genes shared by Res and POR were predicted by network pharmacology, used for Gene Ontology(GO) annotation and Kyoto Encyclopedia of Genes and Genomes(KEGG) pathway enrichment, and then validated by animal experiments. The mice with regular estrous cycle after screening were randomized into normal, POR, and low-and high-dose(20 and 40 mg·kg~(-1), respectively) Res groups. The normal group was administrated with an equal volume of 0.9% sodium chloride solution by gavage, and the mice in other groups with tripterygium glycosides suspension(50 mg·kg~(-1)) by gavage for 2 weeks. After the modeling, the mice in low-and high-dose Res groups were treated with Res by gavage for 2 weeks, and the mice in normal and POR groups with an equal volume of 0.9% sodium chloride solution by gavage. Ovulation induction and sample collection were carried out on the day following the end of treatment. Vaginal smears were collected for observation of the changes in the estrous cycle, the counting of retrieved oocytes, and the measurement of ovarian wet weight and ovarian index. The enzyme-linked immunosorbent assay(ELISA) was employed to measure the levels of anti-mullerian hormone(AMH), follicle-stimulating hormone(FSH), estradiol(E_2), and luteinizing hormone(LH) in the serum. The ovarian tissue morphology and granulosa cell apoptosis were observed by hematoxylin-eosin(HE) staining and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling(TUNEL), respectively. Western blot was employed to determine the protein levels of phosphatidylinositol 3-kinase(PI3K), protein kinase B(AKT), forkhead box O(FOXO) 3a, hypoxia-inducible factor(HIF)-1α, B-cell lymphoma-2(Bcl-2), and Bcl-2-associated X protein(Bax). A total of 222 common targets shared by Res and POR were collected. GO annotation indicated that these targets were mainly involved in oxidative stress response. KEGG enrichment analysis revealed that Res can intervene in POR via PI3K/AKT, HIF-1, and FOXO signaling pathways. Animal experiments showed that the model group had higher rate of estrous cycle disorders, lower number and poorer morphology of normally developed follicles at all levels, more atretic follicles, higher apoptosis of ovarian granulosa cells, lower number of retrieved oocytes, lower ovarian wet weight and ovarian index, higher serum levels of FSH and LH, lower levels of AMH and E_2, higher expression levels of HIF-1α, FOXO3a and Bax, and lower expression levels of PI3K, AKT, and Bcl-2 in the ovarian tissue than the normal group. Compared with the POR group, low-and high-dose Res decreased the rate of estrous cycle disorders, improved the follicle number and morphology, reduced atretic follicles, promoted the apoptosis of ovarian granulosa cells, increased retrieved oocytes, ovarian wet weight and ovarian index, and lowered serum FSH and LH levels. Moreover, Res down-regulated the expression levels of HIF-1α, FOXO3a and Bax, and up-regulated the expression levels of PI3K, AKT and Bcl-2 in the ovarian tissue. In summary, Res can inhibit apoptosis and mitigate poor ovarian response in mice by regulating the PI3K/AKT/FOXO3a and HIF-1α pathways.

Actin-related protein Arp4 regulates euchromatic gene expression and development through H2A.Z deposition in blood-stage Plasmodium falciparum.

BACKGROUND: Malaria caused by Plasmodium spp. is still a major threat to public health globally. The various approaches to developing new antimalarial agents rely on the understanding of the complex regulatory mechanisms of dynamic gene expression in the life-cycle of these malaria parasites. The nuclear members of the evolutionarily conserved actin-related protein nuclear (ARP) superfamily are the major components of nucleosome remodelling complexes. In the human malaria parasite Plasmodium falciparum, bioinformatics analysis has predicted three ARP orthologues: PfArp1, PfArp4 and PfArp6. However, little is known about the biological functions of putative PfArp4. In this study, we aimed to investigate the function and the underlying mechanisms of PfArp4 gene regulation. METHODS: A conditional gene knockdown approach was adopted by incorporating the glucosamine-inducible glmS ribozyme sequence into the 3' UTR of the PfArp4 and PfArp6 genes. The transgenic parasites PfArp4-Ty1-Ribo, PfArp6-Ty1-Ribo and pL6-PfArp4-Ty1::PfArp6-HA were generated by the CRISPR-Cas9 technique. The knockdown effect in the transgenic parasite was measured by growth curve assay and western blot (WB) analysis. The direct interaction between PfArp4 and PfArp6 was validated by co-IFA and co-IP assays. The euchromatic gene expression mediated through H2A.Z (histone H2A variant) deposition and H3K9ac modification at promoters and regulated by PfArp4, was determined by RNA-seq and ChIP-seq. RESULTS: The inducible knockdown of PfArp4 inhibited blood-stage development of P. falciparum. PfArp4 and PfArp6 were colocalized in the nucleus of P. falciparum parasites. PfArp4 gene knockdown altered the global transcriptome. PfArp4 protein colocalized with the histone variant H2A.Z and euchromatic marker H3K9ac in intergenic regions. The inducible downregulation of PfArp4 resulted in the depletion of H2A.Z and lower H3K9ac levels at the upstream regions of eukaryotic genes, thereby repressing the transcriptional abundance of H2A.Z-dependent genes. CONCLUSIONS: Our findings suggest that PfArp4 regulates the cell cycle by controlling H2A.Z deposition and affecting centromere function, contributing to the understanding the complex epigenetic regulation of gene expression and the development of P. falciparum.