Anatomical location and redistribution of G protein-coupled estrogen receptor-1 during the estrus cycle in mouse kidney and specific binding to estrogens but not aldosterone.
Prior studies have linked renoprotective effects of estrogens to G-protein-coupled estrogen receptor-1 (GPER-1) and suggest that aldosterone may also activate GPER-1. Here, the role of GPER-1 in murine renal tissue was further evaluated by examining its anatomical distribution, subcellular distribution and steroid binding specificity. Dual immunofluorescent staining using position-specific markers showed that GPER-1 immunoreactivity primarily resides in distal convoluted tubules and the Loop of Henle (stained with Tamm-Horsfall Protein-1). Lower GPER-1 expression was observed in proximal convoluted tubules marked with megalin, and GPER-1 was not detected in collecting ducts. Plasma membrane fractions prepared from whole kidney tissue or HEK293 cells expressing recombinant human GPER-1 (HEK-GPER-1) displayed high-affinity, specific [(3)H]-17β-estradiol ([(3)H]-E2) binding, but no specific [(3)H]-aldosterone binding. In contrast, cytosolic preparations exhibited specific binding to [(3)H]-aldosterone but not to [(3)H]-E2, consistent with the subcellular distribution of GPER-1 and mineralocorticoid receptor (MR) in these preparations. Aldosterone and MR antagonists, spironolactone and eplerenone, failed to compete for specific [(3)H]-E2 binding to membranes of HEK-GPER-1 cells. Furthermore, aldosterone did not increase [(35)S]-GTP-γS binding to membranes of HEK-GPER-1 cells, indicating that it is not involved in G protein signaling mediated through GPER-1. During the secretory phases of the estrus cycle, GPER-1 is upregulated on cortical epithelia and localized to the basolateral surface during proestrus and redistributed intracellularly during estrus. GPER-1 is down-modulated during luteal phases of the estrus cycle with significantly less receptor on the surface of renal epithelia. Our results demonstrate that GPER-1 is associated with specific estrogen binding and not aldosterone binding and that GPER-1 expression is modulated during the estrus cycle which may suggest a physiological role for GPER-1 in the kidney during reproduction.
Division of Hematology & Oncology, Rhode Island Hospital, Alpert Medical School of Brown University, RI, United States.
Shi-Bin
SB
Cheng
Marine Science Institute, University of Texas at Austin, Port Aransas, TX, United States.
Jing
J
Dong
Marine Science Institute, University of Texas at Austin, Port Aransas, TX, United States.
Yefei
Y
Pang
Department of Pathology and Laboratory Medicine, Rhode Island Hospital, Alpert Medical School of Brown University, RI, United States.
Jessica
J
LaRocca
Department of Pathology and Laboratory Medicine, Rhode Island Hospital, Alpert Medical School of Brown University, RI, United States.
Mary
M
Hixon
Marine Science Institute, University of Texas at Austin, Port Aransas, TX, United States. Electronic address: peter.thomas@utexas.edu.
Peter
P
Thomas
Division of Hematology & Oncology, Rhode Island Hospital, Alpert Medical School of Brown University, RI, United States. Electronic address: ed@radixbiosolutions.com.
Edward J
EJ
Filardo
D000450:Aldosterone / Q000378:metabolism; D000818:Animals; D000077545:Eplerenone; D004958:Estradiol / Q000378:metabolism*; D004971:Estrus / Q000502:physiology*; D005260:Female; D005786:Gene Expression Regulation; D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000378:metabolism; D057809:HEK293 Cells; D006801:Humans; D007686:Kidney Tubules, Distal / Q000166:cytology / Q000378:metabolism*; D008138:Loop of Henle / Q000166:cytology / Q000378:metabolism*; D026561:Low Density Lipoprotein Receptor-Related Protein-2 / Q000235:genetics / Q000378:metabolism; D051379:Mice; D000451:Mineralocorticoid Receptor Antagonists / Q000494:pharmacology; D011485:Protein Binding; D011960:Receptors, Estrogen; D043562:Receptors, G-Protein-Coupled / Q000235:genetics* / Q000378:metabolism; D018161:Receptors, Mineralocorticoid / Q000235:genetics / Q000378:metabolism; D012098:Reproduction / Q000502:physiology*; D013148:Spironolactone / Q000031:analogs & derivatives / Q000494:pharmacology
C532507:GPER1 protein, mouse; D026561:Low Density Lipoprotein Receptor-Related Protein-2; C055127:Lrp2 protein, mouse; D000451:Mineralocorticoid Receptor Antagonists; D011960:Receptors, Estrogen; D043562:Receptors, G-Protein-Coupled; D018161:Receptors, Mineralocorticoid; D013148:Spironolactone; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D000450:Aldosterone; D004958:Estradiol; D000077545:Eplerenone
Aldosterone binding; Distal convoluted tubules; Estradiol binding; Estrus cycle; GPER-1; Mineralocorticoid receptor