scholarly journals Progesterone and estrogen regulate NALCN expression in human myometrial smooth muscle cells

2020 ◽  
Vol 318 (4) ◽  
pp. E441-E452 ◽  
Author(s):  
Chinwendu Amazu ◽  
Xiaofeng Ma ◽  
Clara Henkes ◽  
Juan J. Ferreira ◽  
Celia M. Santi ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Microarray Data ◽  
Quiescent State ◽  
Leak Current ◽  
Response Elements ◽  
Contractile State ◽  
Leak Channel ◽  
Estrogen Response ◽  
Myometrial Smooth Muscle Cell ◽  
Dysfunctional Labor

During pregnancy, the uterus transitions from a quiescent state to an excitable, highly contractile state to deliver the fetus. Two important contributors essential for this transition are hormones and ion channels, both of which modulate myometrial smooth muscle cell (MSMC) excitability. Recently, the sodium (Na+) leak channel, nonselective (NALCN), was shown to contribute to a Na+ leak current in human MSMCs, and mice lacking NALCN in the uterus had dysfunctional labor. Microarray data suggested that the proquiescent hormone progesterone (P4) and the procontractile hormone estrogen (E2) regulated this channel. Here, we sought to determine whether P4 and E2 directly regulate NALCN. In human MSMCs, we found that NALCN mRNA expression decreased by 2.3-fold in the presence of E2 and increased by 5.6-fold in the presence of P4. Similarly, E2 treatment decreased, and P4 treatment restored NALCN protein expression. Additionally, E2 significantly inhibited, and P4 significantly enhanced an NALCN-dependent leak current in MSMCs. Finally, we identified estrogen response and progesterone response elements (EREs and PREs) in the NALCN promoter. With the use of luciferase assays, we showed that the PREs, but not the ERE, contributed to regulation of NALCN expression. Our findings reveal a new mechanism by which NALCN is regulated in the myometrium and suggest a novel role for NALCN in pregnancy.

scholarly journals SLO2.1 and NALCN form a functional complex to modulate myometrial cell excitability

2020 ◽  
Author(s):  
Juan J. Ferreira ◽  
Chinwendu Amazu ◽  
Lis C. Puga-Molina ◽  
Sarah K. England ◽  
Celia M. Santi
Keyword(s):  
Membrane Potential ◽  
Resting Membrane Potential ◽  
Quiescent State ◽  
Leak Current ◽  
Contractile State ◽  
Cell Excitability ◽  
Leak Channel ◽  
Functional Complex ◽  
Myometrial Smooth Muscle Cell ◽  
Myometrial Contractility

AbstractAt the end of pregnancy, the uterus transitions from a quiescent state to an excitable, contractile state. These changes are linked to depolarization of the myometrial smooth muscle cell (MSMC) resting membrane potential. The membrane potential is primarily determined by the balance between an outward potassium (K+) leak current and an inward sodium (Na+) leak current. We recently described a Na+-activated K+ channel (SLO2.1) and a non-selective Na+ leak channel (NALCN) in human MSMCs. Here, we asked whether these channels function together. We show that SLO2.1 currents are activated by an inward NALCN-dependent Na+ leak current, leading to MSMC hyperpolarization. The regulation of the membrane potential by NALCN/SLO2.1 activity modulates both Ca2+ entry through VDCCs, and myometrial contractility. Finally, NALCN and SLO2.1 are in proximity to one another in human MSMCs. We conclude that SLO2.1 and NALCN function together to regulate human MSMC membrane potential and excitability.

scholarly journals Sodium leak channel, non-selective contributes to the leak current in human myometrial smooth muscle cells from pregnant women

2015 ◽  
Vol 21 (10) ◽  
pp. 816-824 ◽  
Author(s):  
Erin L. Reinl ◽  
Rafael Cabeza ◽  
Ismail A. Gregory ◽  
Alison G. Cahill ◽  
Sarah K. England
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Pregnant Women ◽  
Muscle Cells ◽  
Leak Current ◽  
Leak Channel

scholarly journals MON-011 NALCN Expression Is Regulated by Progesterone and Estrogen in Human Myometrial Smooth Muscle Cells

2020 ◽  
Vol 4 (Supplement_1) ◽  
Author(s):  
Chinwendu Amazu ◽  
Xiaofeng Ma ◽  
Clara Henkes ◽  
Juan J Ferreira ◽  
Celia Santi ◽  
...  
Keyword(s):  
Mrna Expression ◽  
Fold Increase ◽  
Quiescent State ◽  
Patch Clamping ◽  
Leak Current ◽  
Myometrial Cells ◽  
Estrogen Response ◽  
Functional Consequences ◽  
Antagonist Ru486 ◽  
Insight Into

Abstract During pregnancy, the uterus transitions from a quiescent state to a highly contractile, excitable state. Both ion channels and hormones are essential for this transition. We recently identified that the Na+ leak channel, non-selective (NALCN) contributes to a leak current in human MSMCs and mice lacking NALCN have prolonged and dysfunctional labor. Additionally, NALCN levels change throughout mouse pregnancy suggesting regulation by hormones of pregnancy, specifically estrogen and progesterone. Here, we tested the hypothesis that P4, a pro-quiescent hormone, and E2, a pro-contractile hormone, regulate NALCN expression and current in the myometrium. In a human immortalized myometrial cells (HM6ERMS2), using qPCR we measured a 2.3 fold decrease and a 5.6 fold increase in NALCN mRNA expression in the presence of E2 and P4, respectively. These findings were also confirmed when NALCN protein expression were measured by immunoblot. Conversely, treatment with the ER antagonist, ICI 182,780, significantly increased NALCN mRNA expression, while treatment with the PR antagonist RU486 significantly decreased NALCN mRNA expression suggesting E2 and P4 work through their respective receptors to regulate NALCN. P4 differentially regulates myometrial activity depending on which progesterone receptor is activated: PRA, promotes contractility, whereas PRB promotes quiescence. Thus to study the effect of each PR, we used a human myometrial cell line stably expressing PRA or PRB, and measured similar increases in NALCN mRNA expression in both cell lines treated with P4. To determine the functional consequences of E2 and P4, we measured NALCN-dependent leak current in MSMCs using whole cell patch clamping. We observed that E2 significantly inhibited while P4 significantly enhanced NALCN current. Finally, we identified estrogen response and progesterone response elements (ERE and PRE) in the NALCN promoter and showed that the PREs contributed to P4 regulation while the ERE did not contribute to the regulation of NALCN expression using luciferase based promoter assays. Overall, our findings show that NALCN is upregulated by P4, the pro-quiescent hormone, and downregulated by E2, the pro-contractile hormone. This data reveals a new mechanism by which NALCN is regulated in the myometrium and may suggest a novel role for NALCN during pregnancy. Further investigation into these novel roles can provide an insight into potential targets to modulate uterine quiescence and contractility.

scholarly journals Two functional estrogen response elements are located upstream of the major chicken vitellogenin gene.

1988 ◽  
Vol 8 (3) ◽  
pp. 1123-1131 ◽  
Author(s):  
J B Burch ◽  
M I Evans ◽  
T M Friedman ◽  
P J O'Malley
Keyword(s):  
Essential Feature ◽  
Coding Region ◽  
Transient Expression Assay ◽  
Specific Expression ◽  
Response Elements ◽  
Estrogen Response ◽  
Pair Sequence ◽  
Estrogen Response Elements ◽  
Vitellogenin Gene ◽  
Simplex Virus

We used a transient-expression assay to identify two estrogen response elements (EREs) associated with the major chicken vitellogenin gene (VTGII). Each element was characterized by its ability to confer estrogen responsiveness when cloned in either orientation next to a chimeric reporter gene consisting of the herpes simplex virus thymidine kinase promoter and the chloramphenicol acetyl transferase-coding region. Deletion analyses indicated that sequences necessary for the distal ERE resided within the region from -626 to -613 (nucleotide positions relative to the VTGII start site) whereas those necessary for the proximal ERE were within the region from -358 to -335. These distal and proximal elements contain, respectively, a perfect copy and an imperfect copy of the 13-base-pair sequence that is an essential feature of the EREs associated with two frog vitellogenin genes. These chicken VTGII EREs mapped near regions that were restructured at the chromatin level when the endogenous VTGII gene was expressed in the liver in response to estradiol. These data suggest a model for the tissue-specific expression of this estrogen-responsive gene.

scholarly journals Differential activation by xenoestrogens of ER alpha and ER beta when linked to different response elements

1998 ◽  
Vol 158 (3) ◽  
pp. R11-R14 ◽  
Author(s):  
WD Pennie ◽  
TC Aldridge ◽  
AN Brooks
Keyword(s):  
Estrogen Receptor ◽  
Luteinizing Hormone ◽  
Molecular Basis ◽  
Estrogen Response Element ◽  
Differential Activation ◽  
Response Elements ◽  
Estrogen Response ◽  
Cell Tissue ◽  
Different Response ◽  
Er Alpha

The discovery of a second estrogen receptor (ER beta) has significant implications for our understanding of the molecular basis for the diverse actions of estrogen. Here we report the differential activation by natural and xenobiotic estrogens of ER alpha and ER beta when linked to different response elements. Receptor mediated activation of reporter constructs containing either the estrogen response element (ERE) from the vitellogenin (Vit) gene or from the luteinizing hormone beta (LH) gene were examined in transiently transfected Cos-1 cells. ER beta preferentially activated the consensus Vit ERE whereas ER alpha showed greater activation at the divergent LH ERE. This differential activation was observed for a number of ligands including estradiol, estrone, bisphenol A, octylphenol and diethystilbestrol. These findings show that the nature of the ERE, as well as the ratio of ER subtypes in a particular cell/tissue, will influence whether particular estrogen responsive genes are activated in the presence of natural or xenobiotic estrogens.

scholarly journals Human URAT1/SLC22A12 gene promoter is regulated by 27-hydroxycholesterol through estrogen response elements

2019 ◽  
Author(s):  
Masaya Matsubayashi ◽  
Yoshihiko M. Sakaguchi ◽  
Yoshiki Sahara ◽  
Hitoki Nanaura ◽  
Sotaro Kikuchi ◽  
...  
Keyword(s):  
Uric Acid ◽  
Serum Uric Acid ◽  
Cholesterol Metabolism ◽  
Gene Promoter ◽  
Human Kidney ◽  
Response Elements ◽  
Estrogen Response ◽  
Uric Acid Transporters ◽  
Estrogen Response Elements ◽  
Phylogenic Relationship

AbstractElevated levels of uric acid, a metabolite of purine in humans, is related to various diseases, such as gout, atherosclerosis and renal dysfunction. The excretion and reabsorption of uric acid to/from urine is tightly regulated by uric acid transporters. The amino acid sequences of uric acid reabsorption transporters, URAT1/SLC22A12, OAT4/SLC22A11, and OAT10/SLC22A13, share closer phylogenic relationship, whereas the gene promoter sequences are distant phylogenic relationship. Through the single-cell RNA-sequencing analysis of an adult human kidney, we found that only a small number of cells express these transporters, despite their role in the regulation of serum uric acid levels. Transcriptional motif analysis on these transporter genes, revealed that the URAT1/SLC22A12 gene promoter displayed the most conserved estrogen response elements (EREs) among the three transporters. The endogenous selective estrogen receptor modulator (SERM) 27-hydroxycholesterol (27HC) had positive effects on the transcriptional activity of URAT1/SLC22A12. We also found that 27HC increased the protein and gene expression of URAT1/SLC22A12 in mouse kidneys and human kidney organoids, respectively. These results strongly suggest the role of 27HC for URAT1/SLC22A12 expression in renal proximal tubules and upregulation of serum uric acid levels and also show the relationship between cholesterol metabolism and serum uric acid regulation.Significance StatementThe elevated levels of serum uric acid cause various diseases, and the excretion/reabsorption of uric acid to/from urine is tightly regulated by the uric acid transporters. We found that despite the role in serum uric acid regulation, only a small number of cells express URAT1/SLC22A12. We also found that URAT1/SLC22A12 gene promoter region has effective estrogen response elements, and endogenous selective estrogen receptor (ER) modulator 27-hydroxycholesterol (27HC) increased URAT1/SLC22A12 expression in the mice kidneys and human kidney organoids. These suggest that 27HC increases URAT1/SLC22A12 expression and upregulate serum uric acid levels. Since 27HC connects cholesterol metabolism, our study indicates the important link between cholesterol metabolism and serum uric acid regulation, and also provides a novel therapeutic approach to hyperuricemia.

Calcium-dependent mechanisms of regulation of smooth muscle contraction

1991 ◽  
Vol 69 (12) ◽  
pp. 771-800 ◽  
Author(s):  
Michael P. Walsh
Keyword(s):  
Smooth Muscle ◽  
Muscle Contraction ◽  
Light Chain ◽  
Myosin Light Chain Kinase ◽  
Myosin Light Chain ◽  
Binding Protein ◽  
Smooth Muscle Contraction ◽  
Light Chains ◽  
Contractile State ◽  
Calmodulin Binding

The contractile state of smooth muscle is regulated primarily by the sarcoplasmic (cytosolic) free Ca2+ concentration. A variety of stimuli that induce smooth muscle contraction (e.g., membrane depolarization, α-adrenergic and muscarinic agonists) trigger an increase in sarcoplasmic free [Ca2+] from resting levels of 120–270 to 500–700 nM. At the elevated [Ca2+], Ca2+ binds to calmodulin, the ubiquitous and multifunctional Ca2+-binding protein. The interaction of Ca2+ with CaM induces a conformational change in the Ca2+-binding protein with exposure of a site(s) of interaction with target proteins, the most important of which in the context of smooth muscle contraction is the enzyme myosin light chain kinase. The interaction of calmodulin with myosin light chain kinase results in activation of the kinase that catalyzes phosphorylation of myosin at serine-19 of each of the two 20-kDa light chains (native myosin is a hexamer composed of two heavy chains (230 kDa each) and two pairs of light chains (one pair of 20 kDa each and the other pair of 17 kDa each)). This simple phosphorylation reaction triggers cycling of myosin cross-bridges along actin filaments and the development of force. Relaxation of the muscle follows removal of Ca2+ from the sarcoplasm, whereupon calmodulin dissociates from myosin light chain kinase regenerating the inactive kinase; myosin is dephosphorylated by myosin light chain phosphatase(s), whereupon it dissociates and remains detached from the actin filament and the muscle relaxes. A substantial body of evidence has been accumulated in support of this central role of myosin phosphorylation–dephosphorylation in the regulation of smooth muscle contraction. However, a wide range of physiological and biochemical studies supports the existence of additional, secondary Ca2+-dependent mechanisms that can modulate or fine-tune the contractile state of the smooth muscle cell. Three such mechanisms have emerged: (i) the actin-, tropomyosin-, and calmodulin-binding protein, calponin; (ii) the actin-, myosin-, tropomyosin-, and calmodulin-binding protein, caldesmon; and (iii) the Ca2+- and phospholipid-dependent protein kinase (protein kinase C).Key words: smooth muscle, Ca2+, myosin phosphorylation, regulation of contraction.

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