Application of Sternberger's unlabeled antibody enzyme method for detection of the estrogen receptor (ER) using a rat primary antibody with rat tissues has been discouraged, presumably because nonspecific staining of endogenous IgG was expected with the required anti-rat IgG bridging antibody. Because the blood-brain barrier greatly reduces immunoglobulin infiltration into the brain, we hypothesized that rat brain tissue could be specifically immunostained using rat IgG primary antibodies. A rat monoclonal anti-ER antibody (H222) specifically stained ERs in the brains of ovariectomized but not in ovariectomized estrogen-treated rats. In contrast, the uterus, a well-perfused target organ stained intensely in a nonspecific fashion. Dense populations of estrogen receptors were observed in the medial preoptic area, the bed nucleus of the stria terminalis, and the arcuate and ventromedial nuclei of the hypothalamus. A monoclonal rat IgG directed against alpha-tubulin labeled primarily cortical dendrites quite distinct from the neuronal nuclei that are the primary antigenic sites for the estrogen receptor antibody. These results confirm that the sensitive unlabeled antibody method can be applied to rat brain tissues, even when the primary antibody is rat IgG and that labeling of endogenous IgG may be used as a simple method to evaluate the integrity of the blood brain barrier.
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http://dx.doi.org/10.1007/BF00315987 | DOI Listing |
J Cachexia Sarcopenia Muscle
February 2025
Division of Physical Therapy and Rehabilitation Science, Department of Family Medicine and Community Health, University of Minnesota, Minneapolis, Minnesota, USA.
Background: With a decline of 17β-estradiol (E2) at menopause, E2 has been implicated in the accompanied loss of skeletal muscle mass and strength. We aimed at characterizing transcriptomic responses of skeletal muscle to E2 in female mice, testing the hypothesis that genes and pathways related to contraction and maintenance of mass are differentially expressed in ovariectomized mice with and without E2 treatment.
Methods: Soleus and tibialis anterior (TA) muscles from C57BL/6 ovariectomized mice treated with placebo (OVX) or E2 (OVX + E2) for 60 days, or from skeletal muscle-specific ERα knockout (skmERαKO) mice and wild-type littermates (skmERαWT), were used for genome-wide expression profiling, quantitative real-time PCR and immunoblotting.
NPJ Breast Cancer
January 2025
Department of Breast Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
Endocrine therapy with CDK4/6 inhibitors is standard for estrogen receptor-positive, HER2-negative metastatic breast cancer (ER+/HER2- MBC), yet clinical resistance develops. Previously, we demonstrated that low doses of palbociclib activate autophagy, reversing initial G1 cell cycle arrest, while high concentrations induce off-target senescence. The autophagy inhibitor hydroxychloroquine (HCQ) induced on-target senescence at lower palbociclib doses.
View Article and Find Full Text PDFJ Reprod Dev
January 2025
Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan.
Hypothalamic arcuate (ARC) kisspeptin neurons are considered the gonadotropin-releasing hormone pulse generator in rats. In virgin rats, the expression of the ARC kisspeptin gene (Kiss1) is repressed by proestrous levels of estradiol-17β (high E2) but not by diestrous levels of E2 (low E2). In lactating rats, ARC Kiss1 expression is repressed by low E2 during late lactation.
View Article and Find Full Text PDFJ Biol Chem
January 2025
Department of Chemistry and Biochemistry, Ohio University, Athens, OH 45701, USA; Molecular and Cellular Biology Program, Ohio University, Athens, OH 45701, USA; Edison Biotechnology Institute, Ohio University, Athens, OH 45701, USA.
Somatic Y537S and D538G mutations within the estrogen receptor alpha ligand-binding domain (ERα-LBD) have been linked to enhanced cell proliferation, survival, and metastases in ER-positive breast cancers. Such mutations are thought to confer ligand-independent receptor activation by increasing the flexibility of helix 12 (H12), a segment within the ERα-LBD that acts as a dynamic regulator of ERα activity. We employed bipartite tetracysteine display coupled with the biarsenical profluorophore FlAsH-EDT to monitor ligand-independent structural transitions of H12 in ERα-LBDs that include Y537S or D538G mutations.
View Article and Find Full Text PDFJ Adv Res
January 2025
Department of Pulmonary and Critical Care Medicine, Shenzhen Institute of Respiratory Diseases, Guangdong Provincial Clinical Research Center for Geriatrics, Shenzhen Clinical Research Center for Geriatrics, Shenzhen People's Hospital, The First Affiliated Hospital, Southern University of Science and Technology, Shenzhen, Guangdong 518020, China; State Key Laboratory for Quality Ensurance and Sustainable Use of Dao-di Herbs, Artemisinin Research Center, Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing 100700, China. Electronic address:
Introduction: Triple-negative breast cancer (TNBC) remains the most aggressive subtype of breast cancer, and effective therapeutic strategies are needed. Estrogen-related receptor alpha (ERRα) is considered a promising target for managing TNBC.
Objectives: Here, we aimed to screen natural products to find downregulator of ERRα and elucidate its mechanism of action.
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