Involvement of BMP-15 in Glucocorticoid Actions on Ovarian Steroidogenesis by Rat Granulosa Cells

Abstract Glucocorticoid receptor (GR) are known to be expressed in the ovary and glucocorticoids are shown to exert direct effects on granulosa cell functions. In the clinical setting, menstrual abnormality, amenorrhea and hypermenorrhea can be shown in patients with glucocorticoid excess. On the other hand, glucocorticoids can also be used for the treatment of PCOS with hyperandrogenism. However, the effects of glucocorticoids on the reproductive system have not been fully elucidated. In the present study, we investigated the influence of glucocorticoids on follicular steroidogenesis using primary culture of rat granulosa cells, by focusing on the ovarian bone morphogenetic proteins (BMPs) acting as a luteinizing inhibitor. Granulosa cells isolated from female immature rats were treated with follicle-stimulating hormone (FSH) in the presence of dexamethasone (Dex) in serum-free conditions. After treatment with Dex for 48 h, the changes of estradiol (E2) and progesterone (P4) production and cAMP synthesis induced by FSH treatments were measured by ELISA. Total RNAs of granulosa cells treated with FSH, Dex and BMPs were extracted and mRNA levels of steroidogenetic factors and enzymes, BMP receptors and Id-1 were quantified by real-time RT-PCR. Phosphorylation of Smad1/5/9 induced by BMPs was evaluated by Western blotting using cell lysates in the presence or absence of Dex. As a result, it was revealed that Dex treatment decreased FSH-induced E2 production by granulosa cells. In accordance with the steroid results, Dex suppressed FSH-induced P450arom mRNA expression as well as FSH-induced cAMP synthesis by granulosa cells. By contrast, Dex treatment augmented FSH-induced P4 production by granulosa cells in a concentration-dependent manner. Dex treatment was found to enhance basal and FSH-induced mRNA levels of P4-synthetic enzymes including P450scc and 3βHSD. Of note, Dex treatment activated the BMP target gene Id-1 transcription and Smad1/5/9 phosphorylation, in particular, induced by BMP-15 among various BMP ligands including BMP-2, -4, -6, -7, -9 and -15. It was also revealed that Dex treatment increased mRNA levels of ALK-6, a type-I receptor for BMP-15, and that BMP-15 treatment in turn upregulated GR mRNA levels expressed by granulosa cells. Given that BMP-15 acts as an inhibitor for P4 production by suppressing FSH-receptor actions, it was suggested that glucocorticoid is functionally linked to the enhancement of endogenous BMP-15, leading to the negative feedback toward the P4 overproduction induced by FSH and Dex in granulosa cells. Collectively, it was revealed that glucocorticoids elicit differential effects on the ovarian steroidogenesis of E2 and P4, in which GR and BMP-15 actions are mutually enhanced in granulosa cells.

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Corticotropin-Releasing Factor Inhibits Luteinizing Hormone-Stimulated P450c17 Gene Expression and Androgen Production by Isolated Thecal Cells of Human Ovarian Follicles1

The Journal of Clinical Endocrinology & Metabolism ◽

10.1210/jcem.83.2.4546 ◽

1998 ◽

Vol 83 (2) ◽

pp. 448-452

Author(s):

H. F. Erden ◽

I. H. Zwain ◽

H. Asakura ◽

S. S. C. Yen

Keyword(s):

Gene Expression ◽

Granulosa Cells ◽

Inhibitory Effect ◽

Corticotropin Releasing Factor ◽

Mrna Levels ◽

Dependent Manner ◽

Messenger Ribonucleic Acid ◽

Estrogen Production ◽

Thecal Cells ◽

Crf System

Recently, we reported that the thecal compartment of the human ovary contains a CRF system replete with gene expression and protein for corticotropin-releasing factor (CRF), CRF-Receptor 1 (CRF-R1), and the blood-derived high affinity CRF-binding protein (CRF-BP). Granulosa cells are devoid of the CRF system. The parallel increases in intensity of CRF, CRF-R1, and 17α-hydroxylase messenger ribonucleic acid (mRNA) and proteins in thecal cells with follicular maturation suggest that the intraovarian CRF system may play an autocrine role regulating androgen biosynthesis, with a downstream effect on estrogen production by granulosa cells. The functionality of the ovarian CRF system may be conditioned by the relative presence of plasma-derived CRF-BP by virtue of its localization of protein, but not transcript in thecal cells and its ability to compete with CRF for the CRF receptor. To further these findings, in the present study we have examined the effect of CRF on LH-stimulated 17α-hydroxylase (P450c17) gene expression and androgen production by isolated thecal cells from human ovarian follicles (11–13 mm). During the 48-h culture, addition of LH (10 ng/mL) to the medium increased by 5- and 6-fold dehydroepiandrosterone and androstenedione production by thecal cells. Remarkably, the LH-stimulated, but not basal, androgen production was inhibited by CRF in a time- and dose-dependent manner. The half-maximal (ID50) effect dose of CRF occurred at 5 × 10−8 mol/L, and at a maximal concentration of 10−6 mol/L, CRF completely inhibited LH-stimulated androgen production. This inhibitory effect of CRF became evident at 12 h (45%), and by 24 h the effect was more pronounced, with a 70% reduction from baseline. As determined by Northern analyses, CRF dose dependently decreased LH-stimulated P450c17 mRNA levels, with a maximal inhibition of 85% P450c17 gene expression at a CRF concentration of 10−6 mol/L. With the addition of 10−6 mol/L of the antagonist α-helical CRF-(9–41), the inhibitory effect of CRF was partially reversed for both P450c17 mRNA (75%) and androgen production (50%), indicating the CRF-R1-mediated event. In conclusion, the present study demonstrated a potent inhibitory effect of CRF on LH-stimulated dehydroepiandrosterone and androstenedione production that appears to be mediated through the reduction of P450c17 gene expression. Thus, the ovarian CRF system may function as autocrine regulators for androgen biosynthesis in the thecal cell compartment to maintain optimal substrate for estrogen biosynthesis by granulosa cells. Further studies to define the role of CRF-BP in the endocrine modulation of the intraovarian CRF system are needed.

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Endothelin (ET)-1 and ET-3 inhibit estrogen and cAMP production by rat granulosa cells in vitro

Journal of Endocrinology ◽

10.1677/joe.0.1570209 ◽

1998 ◽

Vol 157 (2) ◽

pp. 209-215 ◽

Cited By ~ 9

Author(s):

AE Calogero ◽

N Burrello ◽

AM Ossino

Keyword(s):

Granulosa Cells ◽

Ovarian Function ◽

Biological Effects ◽

Female Rats ◽

Dependent Manner ◽

Camp Production ◽

Inhibitory Effects ◽

Ovarian Steroidogenesis ◽

Estrogen Production ◽

Etb Receptor

Endothelin (ET)-1 and ET-3, two peptides with a potent vasoconstrictive property, produce a variety of biological effects in different tissues by acting through two different receptors, the ET-1 selective ET(A) receptor and the non-selective ETB receptor. An increasing body of literature suggests that ET-1 acts as a paracrine/autocrine regulator of ovarian function. Indeed, ETB receptors have been identified in rat granulosa cells and ET-1 is a potent inhibitor of progesterone production. In contrast, inconsistent data have been reported about the role of ET-1 on estrogen production and the effects of ET-3 are not known. Therefore, the present study was undertaken to evaluate the effects of ET-1 and ET-3 on estrogen and cAMP production, and the receptor type involved. Given that prostanoids modulate ovarian steroidogenesis and that many actions of ETs are mediated by these compounds, we also evaluated whether the effects of ETs on estrogen and cAMP production might be prostanoid-mediated. ET-1, ET-3, and safarotoxin-S6c (SFX-S6c), a selective ETB receptor agonist, inhibited basal estrogen production by granulosa cells obtained from immature, estrogen-primed female rats, in a concentration-dependent manner. All three peptides were also capable of inhibiting the production of estrogen stimulated by a half-maximal (1 mIU/ml) and a maximally stimulatory (3 mIU/ml) concentration of FSH, ET-1 and ET-3 dose-dependently suppressed basal and FSH (1 mIU/ml)-stimulated cAMP production. ET-3 and SFX-S6c were significantly more potent than ET-1 in suppressing estrogen production, suggesting that this effect was not mediated by the ET(A) receptor. Indeed, BQ-123, a selective ET(A) receptor antagonist, did not influence the inhibitory effects of ET-1 and ET-3 on basal and FSH-stimulated estrogen release. To determine a possible involvement of prostanoids, we evaluated the effects of maximally effective concentrations of ET-1 and ET-3 on estrogen and cAMP production in the presence of indomethacin, a prostanoid synthesis inhibitor. This compound did not have any effect on the suppressive effects of ETs on basal or FSH (1 mIU/ml)-stimulated estrogen or cAMP production. In conclusion, ET-1 and ET-3 were able to inhibit estrogen and cAMP production by rat granulosa cells, indicating that the inhibitory effects of ETs on ovarian steroidogenesis are not limited to progesterone biosynthesis. This effect does not appear to be mediated by prostanoids or by the classical ET(A) and ETB receptors, at least under these experimental conditions.

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BMP15 Suppresses Progesterone Production by Down-Regulating StAR via ALK3 in Human Granulosa Cells

Molecular Endocrinology ◽

10.1210/me.2013-1233 ◽

2013 ◽

Vol 27 (12) ◽

pp. 2093-2104 ◽

Cited By ~ 47

Author(s):

Hsun-Ming Chang ◽

Jung-Chien Cheng ◽

Christian Klausen ◽

Peter C. K. Leung

Keyword(s):

Granulosa Cells ◽

Critical Role ◽

Regulatory Protein ◽

Granulosa Cell Tumor ◽

Type I ◽

Mrna Levels ◽

Protein Levels ◽

Human Granulosa Cells ◽

Progesterone Production ◽

Steroidogenic Acute Regulatory

In addition to somatic cell-derived growth factors, oocyte-derived growth differentiation factor (GDF)9 and bone morphogenetic protein (BMP)15 play essential roles in female fertility. However, few studies have investigated their effects on human ovarian steroidogenesis, and fewer still have examined their differential effects or underlying molecular determinants. In the present study, we used immortalized human granulosa cells (SVOG) and human granulosa cell tumor cells (KGN) to compare the effects of GDF9 and BMP15 on steroidogenic enzyme expression and investigate potential mechanisms of action. In SVOG cells, neither GDF9 nor BMP15 affects the mRNA levels of P450 side-chain cleavage enzyme or 3β-hydroxysteroid dehydrogenase. However, treatment with BMP15, but not GDF9, significantly decreases steroidogenic acute regulatory protein (StAR) mRNA and protein levels as well as progesterone production. These suppressive effects, along with the induction of Sma and Mad-related protein (SMAD)1/5/8 phosphorylation, are attenuated by cotreatment with 2 different BMP type I receptor inhibitors (dorsomorphin and DMH-1). Furthermore, depletion of activin receptor-like kinase (ALK)3 using small interfering RNA reverses the effects of BMP15 on SMAD1/5/8 phosphorylation and StAR expression. Similarly, knockdown of ALK3 abolishes BMP15-induced SMAD1/5/8 phosphorylation in KGN cells. These results provide evidence that oocyte-derived BMP15 down-regulates StAR expression and decreases progesterone production in human granulosa cells, likely via ALK3-mediated SMAD1/5/8 signaling. Our findings suggest that oocyte may play a critical role in the regulation of progesterone to prevent premature luteinization during the late stage of follicle development.

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Transcriptional Response of Multidrug-Resistant Klebsiella pneumoniae Clinical Isolates to Ciprofloxacin Stress

Canadian Journal of Infectious Diseases and Medical Microbiology ◽

10.1155/2021/5570963 ◽

2021 ◽

Vol 2021 ◽

pp. 1-6

Author(s):

Roman Farooq Alvi ◽

Bilal Aslam ◽

Muhammad Hidayat Rasool ◽

Saima Muzammil ◽

Abu Baker Siddique ◽

...

Keyword(s):

Klebsiella Pneumoniae ◽

Stress Responses ◽

Genetic Resistance ◽

Transcriptional Response ◽

Multidrug Resistant ◽

Mrna Levels ◽

Dependent Manner ◽

Isolation And Identification ◽

Concentration Dependent Manner ◽

High Level

Background. The term “persisters” refers to a small bacterial population that persists during treatment with high antibiotic concentration or dose in the absence of genetic resistance. The present study was designed to investigate the transcriptional response in indigenous Klebsiella pneumoniae under the ciprofloxacin stress. Methods. Isolation and identification of K. pneumoniae were carried out through standard microbiological protocols. The characterization of quinolone resistance was performed by estimating the quinolone susceptibility testing, MIC estimation, and detecting the QRDR and PMQR. Transcriptional response of the isolates to ciprofloxacin was determined using qPCR. Results. Among 34 isolates, 23 (67%) were resistant to ciprofloxacin. Both QRDR (gyrA and gyrB) and PMQR (qnrA, qnrB, and qnrS) were detected in the isolates, and all were found resistant to ciprofloxacin. The mRNA levels of both mutS and euTu under the influence of ciprofloxacin were significantly increased. On ciprofloxacin exposure, the mRNA levels of the DNA damage response element (mutS) were raised in a time-dependent fashion. K. pneumoniae showed high-level resistance to ciprofloxacin in the presence of mutations in QRDR and PMQR genes. Conclusion. The transcriptional response revealed the upregulation of DNA repair and protein folding elements (mutS and euTu) in ciprofloxacin stress and delayed cell division. The ciprofloxacin was found to trigger various stress responses in a time- and concentration-dependent manner.

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Differential bioactivity of four BMP-family members as function of biomaterial stiffness

10.1101/2021.02.10.430282 ◽

2021 ◽

Author(s):

Adrià Sales ◽

Valia Khodr ◽

Paul Machillot ◽

Laure Fourel ◽

Amaris Guevara-Garcia ◽

...

Keyword(s):

Cellular Response ◽

Cell Spreading ◽

Cell Number ◽

Type I ◽

Dependent Manner ◽

Bone Differentiation ◽

Bmp Receptors ◽

Smad Phosphorylation ◽

Matrix Bound ◽

Automated Screening

ABSTRACTWhereas soft biomaterial is not able to induce cell spreading, BMP-2 presented by a soft film has been described to be sufficient to trigger cell spreading, migration and downstream BMP-2 signaling. Based on thin polyelectrolyte films of controlled stiffness, we investigated whether the presentation of four BMP members (2, 4, 7, 9) in a matrix-bound manner may differentially impact cell adhesion and bone differentiation of skeletal progenitors. We performed high content and automated screening of cellular responses, including cell number, cell spreading area, SMAD phosphorylation and alkaline phosphatase activity. The basolateral presentation of the different BMPs allowed us to discriminate the specificity of cellular response and the role of BMP receptors type I, type II, as well as three β integrins, in a BMP type and stiffness-dependent manner.

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Bone Morphogenetic Protein Receptor Complexes on the Surface of Live Cells: A New Oligomerization Mode for Serine/Threonine Kinase Receptors

Molecular Biology of the Cell ◽

10.1091/mbc.11.3.1023 ◽

2000 ◽

Vol 11 (3) ◽

pp. 1023-1035 ◽

Cited By ~ 198

Author(s):

Lilach Gilboa ◽

Anja Nohe ◽

Tanja Geissendörfer ◽

Walter Sebald ◽

Yoav I. Henis ◽

...

Keyword(s):

Bone Morphogenetic Proteins ◽

Transforming Growth Factor ◽

Transforming Growth Factor Β ◽

Live Cells ◽

Type I ◽

Serine Threonine Kinase ◽

Threonine Kinase ◽

Receptor Complexes ◽

Bmp Receptors ◽

Protein Receptor

The bone morphogenetic proteins (BMPs) play important roles in embryogenesis and normal cell growth. The BMP receptors belong to the family of serine/threonine kinase receptors, whose activation has been investigated intensively for the transforming growth factor-β (TGF-β) receptor subfamily. However, the interactions between the BMP receptors, the composition of the active receptor complex, and the role of the ligand in its formation have not yet been investigated and were usually assumed to follow the same pattern as the TGF-β receptors. Here we demonstrate that the oligomerization pattern of the BMP receptors is different and is more flexible and susceptible to modulation by ligand. Using several complementary approaches, we investigated the formation of homomeric and heteromeric complexes between the two known BMP type I receptors (BR-Ia and BR-Ib) and the BMP type II receptor (BR-II). Coimmunoprecipitation studies detected the formation of heteromeric and homomeric complexes among all the BMP receptor types even in the absence of ligand. These complexes were also detected at the cell surface after BMP-2 binding and cross-linking. Using antibody-mediated immunofluorescence copatching of epitope-tagged receptors, we provide evidence in live cells for preexisting heteromeric (BR-II/BR-Ia and BR-II/BR-Ib) and homomeric (BR-II/BR-II, BR-Ia/ BR-Ia, BR-Ib/ BR-Ib, and also BR-Ia/ BR-Ib) oligomers in the absence of ligand. BMP-2 binding significantly increased hetero- and homo-oligomerization (except for the BR-II homo-oligomer, which binds ligand poorly in the absence of BR-I). In contrast to previous observations on TGF-β receptors, which were found to be fully homodimeric in the absence of ligand, the BMP receptors show a much more flexible oligomerization pattern. This novel feature in the oligomerization mode of the BMP receptors allows higher variety and flexibility in their responses to various ligands as compared with the TGF-β receptors.

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Acetic acid modulates spike rate and spike latency to salt in peripheral gustatory neurons of rats

Journal of Neurophysiology ◽

10.1152/jn.00114.2012 ◽

2012 ◽

Vol 108 (9) ◽

pp. 2405-2418 ◽

Cited By ~ 9

Author(s):

Joseph M. Breza ◽

Robert J. Contreras

Keyword(s):

Acetic Acid ◽

Artificial Saliva ◽

Type I ◽

Dependent Manner ◽

Chorda Tympani ◽

Gustatory System ◽

Chorda Tympani Nerve ◽

Concentration Dependent Manner ◽

Lingual Epithelium ◽

Taste Cells

Sour and salt taste interactions are not well understood in the peripheral gustatory system. Therefore, we investigated the interaction of acetic acid and NaCl on taste processing by rat chorda tympani neurons. We recorded multi-unit responses from the severed chorda tympani nerve (CT) and single-cell responses from intact narrowly tuned and broadly tuned salt-sensitive neurons in the geniculate ganglion simultaneously with stimulus-evoked summated potentials to signal when the stimulus contacted the lingual epithelium. Artificial saliva served as the rinse and solvent for all stimuli [0.3 M NH4Cl, 0.5 M sucrose, 0.1 M NaCl, 0.01 M citric acid, 0.02 M quinine hydrochloride (QHCl), 0.1 M KCl, 0.003–0.1 M acetic acid, and 0.003–0.1 M acetic acid mixed with 0.1 M NaCl]. We used benzamil to assess NaCl responses mediated by the epithelial sodium channel (ENaC). The CT nerve responses to acetic acid/NaCl mixtures were less than those predicted by summing the component responses. Single-unit analyses revealed that acetic acid activated acid-generalist neurons exclusively in a concentration-dependent manner: increasing acid concentration increased response frequency and decreased response latency in a parallel fashion. Acetic acid suppressed NaCl responses in ENaC-dependent NaCl-specialist neurons, whereas acetic acid-NaCl mixtures were additive in acid-generalist neurons. These data suggest that acetic acid attenuates sodium responses in ENaC-expressing-taste cells in contact with NaCl-specialist neurons, whereas acetic acid-NaCl mixtures activate distinct receptor/cellular mechanisms on taste cells in contact with acid-generalist neurons. We speculate that NaCl-specialist neurons are in contact with type I cells, whereas acid-generalist neurons are in contact with type III cells in fungiform taste buds.

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Characterization of Human Iodothyronine Sulfotransferases1

The Journal of Clinical Endocrinology & Metabolism ◽

10.1210/jcem.84.4.5590 ◽

1999 ◽

Vol 84 (4) ◽

pp. 1357-1364 ◽

Cited By ~ 3

Author(s):

Monique H. A. Kester ◽

Ellen Kaptein ◽

Thirza J. Roest ◽

Caren H. van Dijk ◽

Dick Tibboel ◽

...

Keyword(s):

Thyroid Hormone ◽

Human Liver ◽

Type I ◽

Dependent Manner ◽

Concentration Dependent Manner ◽

Iodothyronine Deiodinase ◽

Liver Cytosol ◽

Thyroid Hormone Metabolism ◽

Liver And Kidney ◽

Phenol Sulfotransferase

Sulfation is an important pathway of thyroid hormone metabolism that facilitates the degradation of the hormone by the type I iodothyronine deiodinase, but little is known about which human sulfotransferase isoenzymes are involved. We have investigated the sulfation of the prohormone T4, the active hormone T3, and the metabolites rT3 and 3,3′-diiodothyronine (3,3′-T2) by human liver and kidney cytosol as well as by recombinant human SULT1A1 and SULT1A3, previously known as phenol-preferring and monoamine-preferring phenol sulfotransferase, respectively. In all cases, the substrate preference was 3,3′-T2 >> rT3 > T3 > T4. The apparent Km values of 3,3′-T2 and T3 [at 50 μmol/L 3′-phosphoadenosine-5′-phosphosulfate (PAPS)] were 1.02 and 54.9μ mol/L for liver cytosol, 0.64 and 27.8 μmol/L for kidney cytosol, 0.14 and 29.1 μmol/L for SULT1A1, and 33 and 112 μmol/L for SULT1A3, respectively. The apparent Km of PAPS (at 0.1μ mol/L 3,3′-T2) was 6.0 μmol/L for liver cytosol, 9.0μ mol/L for kidney cytosol, 0.65 μmol/L for SULT1A1, and 2.7μ mol/L for SULT1A3. The sulfation of 3,3′-T2 was inhibited by the other iodothyronines in a concentration-dependent manner. The inhibition profiles of the 3,3′-T2 sulfotransferase activities of liver and kidney cytosol obtained by addition of 10 μmol/L of the various analogs were better correlated with the inhibition profile of SULT1A1 than with that of SULT1A3. These results indicate similar substrate specificities for iodothyronine sulfation by native human liver and kidney sulfotransferases and recombinant SULT1A1 and SULT1A3. Of the latter, SULT1A1 clearly shows the highest affinity for both iodothyronines and PAPS, but it remains to be established whether it is the prominent isoenzyme for sulfation of thyroid hormone in human liver and kidney.

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Effects of peroxisome proliferator-activated receptor activation on gonadotropin transcription and cell mitosis induced by bone morphogenetic proteins in mouse gonadotrope LβT2 cells

Journal of Endocrinology ◽

10.1677/joe-07-0138 ◽

2007 ◽

Vol 194 (1) ◽

pp. 87-99 ◽

Cited By ~ 35

Author(s):

Masaya Takeda ◽

Fumio Otsuka ◽

Hiroyuki Otani ◽

Kenichi Inagaki ◽

Tomoko Miyoshi ◽

...

Keyword(s):

Cell Proliferation ◽

Receptor Activation ◽

Bmp Signaling ◽

Peroxisome Proliferator ◽

Mrna Levels ◽

Dependent Manner ◽

Fenofibric Acid ◽

Peroxisome Proliferator Activated Receptor ◽

Bmp Receptors ◽

Cell Mitosis

Involvement of peroxisome proliferator-activated receptor-γ (PPAR-γ ) activation and bone morphogenetic protein (BMP) signaling in regulating cell proliferation and hormonal production of pituitary tumors has been reported, although the underlying mechanism remains poorly understood. Here, we investigated regulatory roles of PPARα and PPARγ in gonadotropin transcription and cell mitosis modulated by pituitary activin/BMP systems using a mouse gonadotropinoma cell line Lβ T2, which expresses activin/BMP receptors, transcription factor Smads, PPARα , and PPARγ . In Lβ T2 cells, BMP signaling shown by Smad1/5/8 phosphorylation and Id-1 transcription was readily activated by BMPs. A PPARγ agonist, pioglitazone significantly reduced BMP-induced DNA synthesis by Lβ T2; whereas the PPARα agonist, fenofibric acid, did not. In accordance with the effects on cell mitosis, pioglitazone but not fenofibric acid significantly decreased BMP-induced Id-1-Luc activation. Neither fenofibric acid nor pioglitazone affected activin signaling detected by (CAGA)9-Luc activity. Both PPARα and PPARγ ligands directly suppressed transcriptional activities of FSHβ , LHβ , and GnRHR. Activation of PPARα and PPARγ increased mRNA levels of follistatin, but did not affect the expression of follistatin-related gene. Thus, PPAR agonists not only directly suppress gonadotropin transcription and BMP signaling, but also inhibit the biological actions of activins which facilitate gonadotropin transcription through upregulating follistatin expression. In addition, pioglitazone increased BMP ligands mRNA, but decreased activin-β B mRNA in Lβ T2 cells. Collectively, PPAR activation differentially regulates gonadotrope cell proliferation and gonadotropin transcription in a ligand-dependent manner.

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BMP-4 inhibits follicle-stimulating hormone secretion in ewe pituitary

Journal of Endocrinology ◽

10.1677/joe.1.05988 ◽

2005 ◽

Vol 186 (1) ◽

pp. 109-121 ◽

Cited By ~ 69

Author(s):

M-O Faure ◽

L Nicol ◽

S Fabre ◽

J Fontaine ◽

N Mohoric ◽

...

Keyword(s):

Growth Factor ◽

Mrna Expression ◽

Transforming Growth Factor Beta ◽

Transforming Growth Factor ◽

Hormone Secretion ◽

Inhibitory Effect ◽

Type I ◽

Mrna Levels ◽

Dependent Manner

Activins and inhibins, members of the transforming growth factor-beta family are able to stimulate and inhibit, respectively, FSH synthesis and release. Other members of this superfamily, the bone morphogenetic proteins (BMPs), may also affect FSH synthesis in the mouse. The aim of this work was to determine whether BMPs are expressed in the ovine pituitary and whether they play a role in the regulation of FSH release. The mRNAs encoding BMP-2, BMP-4, BMP-7 and the oocyte-derived growth factor, growth differentiation factor (GDF)-9 were detected in the pituitaries of cyclic ewes by reverse-transcriptase PCR, as well as the mRNAs encoding the BMP type I receptors, BMPR-IA (activin-receptor-like kinase (ALK)-3) and BMPR-IB (ALK-6), and type II receptors (BMPR-II). Immunolabeling of pituitary sections revealed the presence of BMPR-IA (ALK-3) and BMPR-II in gonadotrope cells. To investigate the potential effects of BMPs on FSH secretion, ewe pituitary cell cultures were treated with BMP-4 (10−11 M to 10−9 M) for 48 h. Interestingly, FSH release was decreased in a dose-dependent manner. At 10−9 M BMP-4 both FSH concentration and FSHβ mRNA expression were reduced by 40% of control values. In contrast, there was no inhibitory effect on either LH or LHβ mRNA expression. A similar result was found with BMP-6. BMP-4 triggered the phosphorylation of Smad1, suggesting that the effect of BMP-4 on FSH secretion is due to the activation of the BMPs signaling pathway. Furthermore, BMP-4 blocked the stimulatory effect of activin on both FSH release and FSHβ mRNA and amplified the suppression of FSH release and FSHβ mRNA levels induced by 17β-estradiol. These results indicate that a functional BMP system operates within the sheep pituitary, at least in vitro, to decrease FSH release and to modulate the effect of activin.

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