Prolyl oligopeptidase regulates progesterone secretion via the ERK signaling pathway in murine luteal cells

In view of ovarian steroidogenesis and luteal construction to explore the effects of Bushen Huoxue recipe in mice of ovarian hyperstimulation

ETHNOPHARMACOLOGICAL RELEVANCE

Bushen Huoxue recipe (BSHXR) is a widely used prescription medicine for treating gynecological diseases. We have previously found that BSHXR can improve the pregnancy outcome of controlled ovarian hyperstimulation (COH) mice by modulating the abnormal high level of progesterone. While the pharmacological mechanism of such therapeutic effect is not clear.

AIM OF THE STUDY

We aimed to investigate the effects of BSHXR on the ovarian steroidogenesis and luteal function in mice undergoing COH.

MATERIALS AND METHODS

A COH mouse model was established via an intraperitoneal injection of 0.4 IU/g pregnant mare serum gonadotropin (PMSG) and 1 IU/g human chorionic gonadotropin (HCG). The histological features of ovaries were observed using hematoxylin-eosin staining. The expression levels of FSHR, LHCGR, and key molecules in ovarian steroidogenesis, including CYP11A1, CYP17A1, CYP19A1, HSD3B1, and StAR, were examined via immunohistochemical staining, western blotting, and RT-qPCR. CD31, VEGFA, and FGF2 levels were assessed to evaluate ovarian vascularization. The protein and mRNA levels of ovarian ERK1/2, p-ERK1/2, MEK1/2, and p-MEK1/2 were also detected using western blotting, RT-qPCR, or immunofluorescence staining.

RESULTS

COH mice had a significantly increased volume and weight of the ovary and number of corpora lutea. In particular, COH exhibited a long-term influence on ovarian FSHR and LHCGR expression, disrupting the levels of CYP11A1, HSD3B1, and CYP17A1, causing poorer luteal angiogenesis. Compared with normal mice, the expression levels of ovarian VEGFA and FGF2 in COH mice were considerably lower on Day 1 after PMSG. On concomitant HCG treatment, both VEGFA and FGF2 expression surged dramatically on ED1 and then declined on ED4 and ED8. Moreover, the expression pattern of MEK1/2-ERK1/2 was almost consistent with that of VEGFA and FGF2. After treatment, BSHXR increased ovarian LHCGR, FSHR, CYP11A1, HSD3B1, and CYP17A1 levels, boosted luteal vascularization, and restored MEK1/2-ERK1/2 signaling in COH mice.

CONCLUSION

BSHXR restored the abnormally high progesterone level by regulating the CYP11A1 and HSD3B1 expression as well as promoted luteal angiogenesis, which was related with LHCGR-MEK1/2-ERK1/2-VEGFA/FGF2 signaling pathway in the ovary. This effect prevented the fluctuation of sex hormones in COH mice and benefited the outcome of pregnancy.

Lipid Deposition and Progesterone Synthesis Are Increased by miR-181b-5p through RAP1B/ERK1/2 Pathway in Chicken Granulosa Cells

Steroid hormones secreted by granulosa cells are essential for maintaining normal development of chicken follicles. Our previous sequencing data indicated that miR-181b-5p and RAS-related protein 1B (RAP1B) appeared to function in chicken granulosa cells, which was further explored in this study. The results suggested that miR-181b-5p facilitated the aggregation of lipid droplets and the synthesis of progesterone. In contrast, RAP1B astricted lipid deposition and progesterone secretion. Cotransfection of the RAP1B overexpression vector with miR-181b-5p mimic eliminated the promoting effect of miR-181b-5p. Dual-luciferase reporter assay confirmed that miR-181b-5p bound directly to the 3' untranslated region (3' UTR) of RAP1B. We also found that miR-181b-5p and RAP1B reduced and enhanced the phosphorylation levels of extracellular signal-regulated kinases 1 and 2 (ERK1/2), respectively. The application of ERK1/2 activators and inhibitors demonstrated that ERK1/2 is a negative regulator of lipid deposition and progesterone synthesis. In conclusion, we revealed that miR-181b-5p accelerated lipid deposition and progesterone synthesis through the RAP1B/ERK1/2 pathway in chicken granulosa cells. miR-181b-5p and RAP1B may serve as new biomarkers in breeding to improve chicken reproductive performance and prevent ovary-related diseases.

Abnormal Expression of Prolyl Oligopeptidase (POP) and Its Catalytic Products Ac-SDKP Contributes to the Ovarian Fibrosis Change in Polycystic Ovary Syndrome (PCOS) Mice

Polycystic ovary syndrome (PCOS) is an endocrine disorder and metabolic syndrome. Ovarian fibrosis pathological change in PCOS has gradually attracted people's attention. In this study, we constructed a PCOS mouse model through the use of dehydroepiandrosterone. Sirius red staining showed that the ovarian tissues in PCOS mice had obvious fibrosis. Prolyl oligopeptidase (POP) is a serine protease and N-acetyl-seryl-aspartyl-lysyl-proline (Ac-SDKP) is its catalytic product. Studies show that abnormal expression and activity of POP and Ac-SDKP are closely related to tissue fibrosis. It was found that the expression of POP and Ac-SDKP was decreased in the ovaries of PCOS mice. Further studies showed that POP and Ac-SDKP promoted the expression of matrix metalloproteinases 2 (MMP-2) expression and decreased the expression of transforming growth factor beta 1 (TGF-β1) in granulosa cells. Hyperandrogenemia is a typical symptom of PCOS. We found that testosterone induced the low expression of POP and MMP2 and high expression of TGF-β1 in granulosa cells. POP overexpression and Ac-SDKP treatment inhibited the effect of testosterone on TGF-β1 and MMP2 in vitro and inhibited ovarian fibrosis in the PCOS mouse model. In conclusion, PCOS ovarian tissue showed obvious fibrosis. Low expression of POP and Ac-SDKP and changes in fibrotic factors contribute to the ovarian pathological fibrosis induced by androgen.

Therapeutic Effect of Novel Cyanopyrrolidine-Based Prolyl Oligopeptidase Inhibitors in Rat Models of Amnesia

Prolyl oligopeptidase (POP) is a large cytosolic serine peptidase that is altered in patients with Alzheimer’s disease, Parkinsonian syndrome, muscular dystrophies, and other denervating diseases. Thus, POP may represent a relevant therapeutic target for treatment of neuropsychiatric disorders and neurodegenerative diseases. Here, we report the characterization of five novel cyanopyrrolidine-based compounds (BocTrpPrdN, BocGlyPrdN, CbzMetPrdN, CbzGlnPrdN, and CbzAlaPrdN) and show that they are potent inhibitors of POP and are predicted to penetrate the blood-brain barrier (BBB). Indeed, we show that CbzMetPrdN penetrates the rat BBB and effectively inhibits POP in the brain when administered intraperitoneally. Furthermore, molecular modeling confirmed these compounds likely inhibit POP via interaction with the POP catalytic site. We evaluated protective effects of the cyanopyrrolidine-based POP inhibitors using scopolamine- and maximal electroshock-induced models of amnesia in rats and showed that BocTrpPrdN, BocGlyPrdN, CbzMetPrdN, and CbzGlnPrdN significantly prolonged conditioned passive avoidance reflex (CPAR) retention time when administered intraperitoneally (1 and 2 mg/kg) before evaluation in both models of amnesia, although CbzAlaPrdN was not effective in scopolamine-induced amnesia. Our data support previous reports on the antiamnesic effects of prolinal-based POP inhibitors and indicate an important role of POP in the regulation of learning and memory processes in the CNS.

Effect of prenatal exposure to Benzo[a]pyrene on ovarian toxicity and reproductive dysfunction: Protective effect of atorvastatin in the embryonic period

As an environmental contaminant, Benzo[a]pyrene (B[a]P; BaP) disrupts the antioxidant signaling and thus leads to the induction of oxidative stress and the damage of DNA in the ovary. low-dose atorvastatin (ATV) has antioxidant and anti-apoptotic properties. The present study aimed to survey the effects of prenatal exposure to BaP on ovarian toxicity and also to investigate the protective role of ATV in reducing ovarian toxicity. In this study, rats were divided into seven groups: control, ATV (10 mg/kg), oil, BaP (10 and 20 mg/kg), and ATV + BaP (10 and 20 mg/kg). BaP and ATV were administrated from gestation day 7-16 (GD7 to GD16), orally. 10 weeks after the birth, female offsprings were examined for oxidative stress markers, sex hormones, ovarian and tubular tissue structure, and the apoptosis markers. Data showed that BaP significantly reduced glutathione, increased malondialdehyde level, and disrupted the tissue structure of the ovary. Moreover, estrogen and progesterone levels significantly decreased in the offsprings rats. Also, BaP increased caspase-3 immunoreactivity. Atorvastatin treatment along with BaP in the embryonic period were able to bring the antioxidant status and sex hormones levels relatively close to normal. Besides, histological findings showed that atorvastatin was able to improve ovarian and oviduct abnormalities caused by BaP. Based on the above studies be concluded that atorvastatin in the embryonic during was able to reduce ovarian damage caused by BaP with antioxidant and anti-apoptotic properties.

Preliminary Investigation on the Involvement of Cytoskeleton-Related Proteins, DAAM1 and PREP, in Human Testicular Disorders

Herein, for the first time, the potential relationships between the cytoskeleton-associated proteins DAAM1 and PREP with different testicular disorders, such as classic seminoma (CS), Leydig cell tumor (LCT), and Sertoli cell-only syndrome (SOS), were evaluated. Six CS, two LCT, and two SOS tissue samples were obtained during inguinal exploration in patients with a suspect testis tumor based on clinical examination and ultrasonography. DAAM1 and PREP protein levels and immunofluorescent localization were analyzed. An increased DAAM1 protein level in CS and SOS as compared to non-pathological (NP) tissue was observed, while LCT showed no significant differences. Conversely, PREP protein level increased in LCT, while it decreased in CS and SOS compared to NP tissue. These results were strongly supported by the immunofluorescence staining, revealing an altered localization and signal intensity of DAAM1 and PREP in the analyzed samples, highlighting a perturbed cytoarchitecture. Interestingly, in LCT spermatogonia, a specific DAAM1 nuclear localization was found, probably due to an enhanced testosterone production, as confirmed by the increased protein levels of steroidogenic enzymes. Finally, although further studies are needed to verify the involvement of other formins and microtubule-associated proteins, this report raised the opportunity to indicate DAAM1 and PREP as new potential markers, supporting the cytoskeleton dynamics changes occurring during normal and/or pathological cell differentiation.

Altered Expression of DAAM1 and PREP Induced by Cadmium Toxicity Is Counteracted by Melatonin in the Rat Testis

Cadmium (Cd) is one of the most toxic pollutants for health due to its accumulation in several tissues, including testis. This report confirms that Cd increased oxidative stress and apoptosis of germ and somatic cells and provoked testicular injury, as documented by biomolecular and histological alterations, i.e., CAT and SOD activity, the protein level of steroidogenic enzymes (StAR and 3β-HSD), and morphometric parameters. Additionally, it further documents the melatonin (MLT) coadministration produces affects in mitigating Cd-induced toxicity on adult rat testis, as demonstrated by the reduction of oxidative stress and apoptosis, with reversal of the observed histological changes; moreover, a role of MLT in partially restoring steroidogenic enzymes expression was evidenced. Importantly, the cytoarchitecture of testicular cells was perturbed by Cd exposure, as highlighted by impairment of the expression and localization of two cytoskeleton-associated proteins DAAM1 and PREP, which are involved in the germ cells' differentiation into spermatozoa, altering the normal spermatogenesis. Here, for the first time, we found that the co-treatment with MLT attenuated the Cd-induced toxicity on the testicular DAAM1 and PREP expression. The combined findings provide additional clues about a protective effect of MLT against Cd-induced testicular toxicity by acting on DAAM1 and PREP expression, encouraging further studies to prove its effectiveness in human health.

Long non-coding RNAs in ovarian granulosa cells

Granulosa cells (GCs) are somatic cells surrounding oocytes within follicles and are essential for folliculogenesis. Pathological changes in GCs are found in several ovarian disorders. Recent reports have indicated that long non-coding RNAs (lncRNAs), which modulate gene expression via multiple mechanisms, are key regulators of the normal development of GCs, follicles, and ovaries. In addition, accumulating evidence has suggested that lncRNAs can be utilized as biomarkers for the diagnosis and prognosis of GC-related diseases, such as polycystic ovary syndrome (PCOS) and premature ovarian insufficiency (POI). Therefore, lncRNAs not only play a role in GCs that are involved in normal folliculogenesis, but they may also be considered as potential candidate biomarkers and therapeutic targets in GCs under pathological conditions. In the future, a detailed investigation of the in vivo delivery or targeting of lncRNAs and large-cohort-validation of the clinical applicability of lncRNAs is required.