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  • The nuclear receptor cofactor receptor-interacting protein 140 is a positive regulator of amphiregulin expression and cumulus cell-oocyte complex expansion in the mouse o ... 20308529

    The nuclear receptor cofactor receptor-interacting protein 140 (RIP140) is essential for cumulus cell-oocyte complex (COC) expansion, follicular rupture, and oocyte release during ovulation. The expression of many genes necessary for COC expansion is impaired in the absence of RIP140, but the studies herein document that their expression can be restored and COC expansion rescued by treatment with the epidermal growth factor (EGF)-like factor amphiregulin (AREG) both in vitro and in vivo. We demonstrate by several approaches that RIP140 is required for the expression of the EGF-like factors in granulosa cells, but the dependence of genes involved in cumulus expansion, including Ptgs2 Has2, Tnfaip6, and Ptx3, is indirect because they are induced by AREG. Treatment of granulosa cells with forskolin to mimic the effects of LH increases AREG promoter activity in a RIP140-dependent manner that 1) requires an intact cAMP response element in the proximal promoter region of the Areg gene and 2) involves its actions as a coactivator for cAMP response element-binding protein/c-Jun transcription factors. Although human chorionic gonadotropin and AREG coadministration is sufficient to restore ovulation fully in RIP140 heterozygous mice in vivo, both follicular rupture and ovulation remain impaired in the RIP140 null mice. Thus, we conclude that although the level of RIP140 expression in the ovary is a crucial factor required for the transient expression of EGF-like factors necessary for cumulus expansion, it also plays a role in other signaling pathways that induce follicular rupture.
    Document Type:
    Reference
    Product Catalog Number:
    06-519
    Product Catalog Name:
    Anti-phospho-CREB (Ser133) Antibody

  • Crataegus oxycantha extract attenuates apoptotic incidence in myocardial ischemia-reperfusion injury by regulating Akt and HIF-1 signaling pathways. 20729753

    The objective of the present study was to evaluate the efficacy and mechanism of Crataegus oxycantha (COC) extract in preventing ischemia-reperfusion (IR) injury in an in vivo rat model of acute myocardial infarction induced by a 30-minute regional ischemia followed by 72 hours of reperfusion. The COC extract [100 mg/(kg body weight)] was administered 12 hours after the surgical procedure and then at 24-hour intervals for 3 days. Animals treated with COC extract showed a significant decrease in creatine kinase activity and infarct size. At the molecular level, COC administration resulted in a significant attenuation of PTEN (phosphatase and tensin homolog deleted on chromosome 10) and upregulation of phospho-Akt and c-Raf levels in the heart. As a consequence, cleaved caspase-9 and cleaved caspase-7 levels were significantly downregulated, indicating negative regulation of apoptosis by COC extract. In part with the hypoxia-inducible factor (HIF) signaling pathway, COC extract administration significantly upregulated the prolyl hydroxylase-2 level. In contrast, other proapoptotic proteins such as nuclear factor-κB, cytochrome c, apoptosis-inducing factor, and cleaved poly(adenosine diphosphate-ribose) polymerase levels were significantly downregulated in the COC-treated group when compared with the untreated control group. The results suggested that COC extract attenuated apoptotic incidence in the experimental myocardial ischemia-reperfusion model by regulating Akt and HIF-1 signaling pathways.
    Document Type:
    Reference
    Product Catalog Number:
    17-371
    Product Catalog Name:
    EZ-ChIP™

  • Combined oral contraceptive synergistically activates mineralocorticoid receptor through histone code modifications. 26506558

    Clinical studies have shown that the use of combined oral contraceptive in pre-menopausal women is associated with fluid retention. However, the molecular mechanism is still elusive. We hypothesized that combined oral contraceptive (COC) ethinyl estradiol (EE) and norgestrel (N) synergistically activates mineralocorticoid receptor (MR) through histone code modifications. Twelve-week-old female Sprague-Dawley rats were treated with olive oil (control), a combination of 0.1µg EE and 1.0µg N (low COC) or 1.0µg EE and 10.0µg N (high COC) as well as 0.1 or 1.0µg EE and 1.0 or 10.0µg N daily for 6 weeks. Expression of MR target genes in kidney cortex was determined by quantitative real-time polymerase chain reaction. MR was quantified by western blot. Recruitment of MR and RNA polymerase II (Pol II) on promoters of target genes as well as histone code modifications was analyzed by chromatin immunoprecipitation assay. Treatment with COC increased renal cortical expression of MR target genes such as serum and glucocorticoid-regulated kinase 1 (Sgk-1), glucocorticoid-induced leucine zipper (Gilz), epithelial Na(+)channel (Enac) and Na(+)-K(+)-ATPase subunit α1 (Atp1a1). Although COC increased neither serum aldosterone nor MR expression in kidney cortex, it increased recruitment of MR and Pol II in parallel with increased H3Ac and H3K4me3 on the promoter regions of MR target genes. However, treatment with EE or N alone did not affect renal cortical expression of Sgk-1, Gilz, Enac or Atp1a1. These results indicate that COC synergistically activates MR through histone code modifications.
    Document Type:
    Reference
    Product Catalog Number:
    17-371
    Product Catalog Name:
    EZ-ChIP™

  • The dynamics of connexin expression, degradation and localisation are regulated by gonadotropins during the early stages of in vitro maturation of swine oocytes. 23861906

    Gap junctional communication (GJC) plays a primordial role in oocyte maturation and meiotic resumption in mammals by directing the transfer of numerous molecules between cumulus cells and the oocyte. Gap junctions are made of connexins (Cx), proteins that regulate GJC in numerous ways. Understanding the dynamic regulation of connexin arrangements during in vitro maturation (IVM) could provide a powerful tool for controlling meiotic resumption and consequently in vitro development of fully competent oocytes. However, physiological events happening during the early hours of IVM may still be elucidated. The present study reports the dynamic regulation of connexin expression, degradation and localization during this stage. Cx43, Cx45 and Cx60 were identified as the main connexins expressed in swine COC. Cx43 and Cx45 transcripts were judged too static to be a regulator of GJC, while Cx43 protein expression was highly responsive to gonadotropins, suggesting that it might be the principal regulator of GJC. In addition, the degradation of Cx43 expressed after 4.5 h of IVM in response to equine chorionic gonadotropin appeared to involve the proteasomal complex. Cx43 localisation appeared to be associated with GJC. Taken together, these results show for the first time that gonadotropins regulate Cx43 protein expression, degradation and localisation in porcine COC during the first several hours of IVM. Regulation of Cx43 may in turn, via GJC, participate in the development of fully competent oocytes.
    Document Type:
    Reference
    Product Catalog Number:
    Multiple
    Product Catalog Name:
    Multiple

  • The Cholinesterase-like Domain, Essential in Thyroglobulin Trafficking for Thyroid Hormone Synthesis, Is Required for Protein Dimerization. 19276074

    The carboxyl-terminal cholinesterase-like (ChEL) domain of thyroglobulin (Tg) has been identified as critically important in Tg export from the endoplasmic reticulum. In a number of human kindreds suffering from congenital hypothyroidism, and in the cog congenital goiter mouse and rdw rat dwarf models, thyroid hormone synthesis is inhibited because of mutations in the ChEL domain that block protein export from the endoplasmic reticulum. We hypothesize that Tg forms homodimers through noncovalent interactions involving two predicted alpha-helices in each ChEL domain that are homologous to the dimerization helices of acetylcholinesterase. This has been explored through selective epitope tagging of dimerization partners and by inserting an extra, unpaired Cys residue to create an opportunity for intermolecular disulfide pairing. We show that the ChEL domain is necessary and sufficient for Tg dimerization; specifically, the isolated ChEL domain can dimerize with full-length Tg or with itself. Insertion of an N-linked glycan into the putative upstream dimerization helix inhibits homodimerization of the isolated ChEL domain. However, interestingly, co-expression of upstream Tg domains, either in cis or in trans, overrides the dimerization defect of such a mutant. Thus, although the ChEL domain provides a nidus for Tg dimerization, interactions of upstream Tg regions with the ChEL domain actively stabilizes the Tg dimer complex for intracellular transport.
    Document Type:
    Reference
    Product Catalog Number:
    MAB303
    Product Catalog Name:
    Anti-Acetylcholinesterase Antibody, clone AE-1