New insights of subfertility among transplanted women: Immunosuppressive drug FK506 leads to calcium leak and oocyte activation before fertilization

FOXG1 is involved in mouse ovarian functions and embryogenesis

TGF-β superfamily has long been demonstrated to be essential for folliculogenesis and luteinization. Forkhead box G1 (FOXG1, also known as BF1), a member of the FOX family and an inhibitor of TGF-β signaling pathway, is a nucleocytoplasmic transcription factor that is essential for forebrain development. FOXG1 is involved in neurodevelopment and cancer pathology, however, little is known about the role of FOXG1 in reproduction. In this study, the spatiotemporal expression pattern of FOXG1 was examined during early mouse oocyte and embryonic development and its role during corpora luteum (CL) formation was further elucidated. The results showed that FOXG1 is localized in oocytes, theca cells (TCs) and CLs. After fertilization, FOXG1 is expressed at all stages during early embryogenesis, from zygotes to blastocysts. Following gonadotropin administration in immature mice, the expression of Foxg1 significantly increased along with steroidogenic genes, including Star, Hsd3β, Cyp11a1, as well as Cyp17a1 and Cyp19a1. The latter two first increased after pregnant mare serum gonadotropin stimulation, then decreased in response to hCG treatment. In addition, silencing of Foxg1 significantly reduced the concentration of testosterone and estrogen in cultured primary granulosa cells (GCs) and TCs (P < 0.05). Mechanistic studies demonstrated that the expression level of genes that are critical in estrogen synthesis were significantly reduced after Foxg1 silencing, including Cyp17a1 and Cyp19a1. In conclusion, FOXG1 is expressed in a stage-specific manner during folliculogenesis and embryogenesis and exerts a regulatory influence on testosterone and estrogen synthesis.

miR-944 Suppresses EGF-Induced EMT in Colorectal Cancer Cells by Directly Targeting GATA6

Background

miR-944 belongs to the MicroRNAs family, as shown in our previous study, and is essential in the colorectal cancer (CRC) progression. It is negatively associated with invasion depth and lymph node status. Epithelial-mesenchymal transition (EMT) is essential in tumor invasion and metastasis. However, the relationship between miR-944 and EMT in CRC is unknown and should be further investigated.

Methods

Epithelial–mesenchymal transition (EMT) progression in CRC cell lines was detected with Cell morphology and Western blotting. CRC cell migration and invasion were examined using Transwell assays. Transcriptome and clinical data were obtained from The Cancer Genome Atlas (TCGA) database. The potential pathway of miR-944 and GATA6 were predicted using KEGG analysis. Colocalization was validated using immunofluorescence and Immunohistochemistry. Nuclear and Cytoplasmic Protein Extraction assays were conducted to determine the effects of miR-944 on Wnt/β-catenin signaling.

Results

We found that miR‑944 influences EGF-induced EMT malignant phenotype in vitro. KEGG analyses showed that miR-944 and GATA6 are associated with EMT related pathways, wnt signaling pathways. On the other hand, Western Blot analyses showed that miR-944 can regulate EMT and wnt-β-catenin pathway-related protein, including β-catenin, ZEB1, snail1 via GATA6 regulation. miR-944 also abrogates E-ca after EGF induction. Immunohistochemistry (IHC) and Immunofluorescence (IF) co-expression showed that GATA6 expression is positively associated with β-catenin and ZEB1. GATA6 silencing can reverse EMT malignant phenotype and alterations of related protein induced by miR-944. Quantitative polymerase chain reaction analysis results showed that miR-944 is negatively associated with the UICC stage (P= 0.02), lymph nodes (p=0.04), and liver metastasis (p=0.03). Moreover, patients with high miR-944 expression have better survival (p=0.045). We finally combined miR-944 and GATA6 and found that miR-944/GATA6 ratio could be a novel prognostic biomarker in the TCGA dataset and it is an independent risk prognosis factor (p=0.045).

Conclusion

Our results suggest that miR-944 suppresses the aggressive biological processes by directly repressing GATA6 expression and could be a potential candidate for therapeutic applications in CRC.

Ca2+ ionophore A23187 inhibits ATP generation reducing mouse sperm motility and PKA-dependent phosphorylation

Male infertility is a global problem in modern society of which capacitating defects are a major cause. Previous studies have demonstrated that Ca²⁺ ionophore A23187 can make mouse sperm capable of fertilizing in vitro, which may aid in clinical treatment of capacitating defects. However, the detailed role and mechanism of Ca²⁺ in the capacitating process are still unclear especially how A23187 quickly renders sperm immotile and inhibits cAMP/PKA-mediated phosphorylation. We report that A23187 induces a Ca²⁺ flux in the mitochondria enriched sperm tail and excess Ca²⁺ inhibits key metabolic enzymes involved in acetyl-CoA biosynthesis, TCA cycle and electron transport chain pathways resulting in reduced ATP and overall energy production, however this flux does not destroy the structure of the sperm tail. Due to the decrease in ATP production, which is the main phosphate group donator and the power of sperm, the sperm is rendered immobile and PKA-mediated phosphorylation is inhibited. Our study proposed a possible mechanism through which A23187 reduces sperm motility and PKA-mediated phosphorylation from ATP generation, thus providing basic data for exploring the functional roles of Ca²⁺ in sperm in the future.

FK506 regulates Ca2+ release evoked by inositol 1,4,5-trisphosphate independently of FK-binding protein in endothelial cells

Background and Purpose

FK506 and rapamycin are modulators of FK‐binding proteins (FKBP) that are used to suppress immune function after organ and hematopoietic stem cell transplantations. The drugs share the unwanted side‐effect of evoking hypertension that is associated with reduced endothelial function and nitric oxide production. The underlying mechanisms are not understood. FKBP may regulate IP₃ receptors (IP₃R) and ryanodine receptors (RyR) to alter Ca²⁺ signalling in endothelial cells.

Experimental Approach

We investigated the effects of FK506 and rapamycin on Ca²⁺ release via IP₃R and RyR in hundreds of endothelial cells, using the indicator Cal‐520, in intact mesenteric arteries from male Sprague‐Dawley rats. IP₃Rs were activated by acetylcholine or localised photo‐uncaging of IP₃, and RyR by caffeine.

Key Results

While FKBPs were present, FKBP modulation with rapamycin did not alter IP₃‐evoked Ca²⁺ release. Conversely, FK506, which modulates FKBP and blocks calcineurin, increased IP₃‐evoked Ca²⁺ release. Inhibition of calcineurin (okadiac acid or cypermethrin) also increased IP₃‐evoked Ca²⁺ release and blocked FK506 effects. When calcineurin was inhibited, FK506 reduced IP₃‐evoked Ca²⁺ release. These findings suggest that IP₃‐evoked Ca²⁺ release is not modulated by FKBP, but by FK506‐mediated calcineurin inhibition. The RyR modulators caffeine and ryanodine failed to alter Ca²⁺ signalling suggesting that RyR is not functional in native endothelium.

Conclusion and Implications

The hypertensive effects of the immunosuppressant drugs FK506 and rapamycin, while mediated by endothelial cells, do not appear to be exerted at the documented cellular targets of Ca²⁺ release and altered FKBP binding to IP₃ and RyR.

Melatonin protects against Epirubicin-induced ovarian damage

One major side effect of chemotherapy that young women with cancer suffer from is ovarian damage. Therefore, it is necessary to study the pathogenesis of chemotherapeutic drugs in order to develop pharmaceutical agents to preserve fertility. Epirubicin is one of the commonly used chemotherapy drugs for breast cancer patients. This research explored the side effects of epirubicin in mice. We found that epirubicin significantly reduced the body weight, the weight of the ovaries and uteri, and the pups' number, while melatonin, which is extremely resistant to oxidation, significantly reduced these damages. Moreover, co-treatment with melatonin prevented epirubicin-induced decrease in E<inf>2</inf> and progesterone, and the loss of follicles. Mechanism study showed that melatonin significantly reduced the levels of proapoptotic genes p53, Caspase3, and Caspase9 while it upregulated antiapoptotic factors Bcl-2 and Bcl2l1, and antioxidant genes superoxide dismutase 1 and catalase compared with the epirubicin group. In addition, melatonin markedly reduced reactive oxygen species (ROS) and the transcription of Caspase12 and Chop, which is vital in endoplasmic reticulum stress (ERS)-mediated apoptosis. These results indicate melatonin protects against epirubicin-induced ovarian damage by reducing ROS-induced ERS. Therefore, melatonin has a therapeutic potential for the protection of ovarian function and preservation of fertility during chemotherapy.