Potential role of G-protein-coupled receptor 30 (GPR30) in estradiol-17β-stimulated IGF-I mRNA expression in bovine satellite cell cultures

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Abstract

Androgenic and estrogenic steroids enhance muscle growth in animals and humans. Estradiol-17β (E2) and trenbolone acetate (TBA) (a synthetic testosterone analog) increased IGF-I mRNA expression in bovine muscle satellite cell (BSC) cultures. The goal of this study was to evaluate the mechanisms responsible for this increase by evaluating the effects of ICI 182 780 (an E2 receptor antagonist), flutamide (an androgen receptor inhibitor), G1 (a GPR30 agonist), and BSA-conjugated E2 on E2 and/or TBA-stimulated IGF-I mRNA expression in BSC cultures. Flutamide completely suppressed TBA-stimulated IGF-I mRNA expression in BSC cultures. ICI 182 780 did not suppress E2-stimulated IGF-I mRNA expression and 100 nM ICI 182 780 enhanced (93%, p < 0.05) IGF-I mRNA levels in BSC cultures. G1 (100 nM) stimulated IGF-I mRNA expression (100%, p < 0.05) but had no effect on proliferation in BSC cultures. E2-BSA, which cannot cross the cell membrane, stimulated IGF-I mRNA expression (approximately 100%, p < 0.05) in BSC but even at extremely high concentrations had no effect on proliferation. In summary, our data indicate the E2-stimulation of proliferation and E2-stimulation of IGF-I mRNA expression in BSC cultures occur via different mechanisms. Our previous results showing that ICI 182 780 inhibited BSC proliferation and results of the current study showing lack of response to E2-BSA or G1 suggest that E2-stimulated proliferation in BSC cultures is mediated through classical estrogen receptors. Stimulation by ICI 182 780, G1 and E2-BSA suggests the E2-stimulated IGF-I mRNA expression in BSC cultures is mediated through the GPR30 receptor.

Introduction

Both androgenic and estrogenic steroids are routinely used to enhance muscle growth in domestic meat producing animals, in particular cattle [1]. Additionally, androgens reduce loss of muscle mass and strength in aging or hypogonadal men [2], [3]; and estrogen replacement therapy in postmenopausal women reportedly enhances both muscle mass and strength [4], [5], [6]. Feedlot steers implanted with a combined implant containing 120 mg of the synthetic androgen trenbolone acetate (TBA) and 24 mg of 17β-estradiol (E2), exhibited increased rate of gain (20–25%), increased feed efficiency (15–20%), increased carcass protein, and increased longissimus muscle area [7]. Circulating IGF-I concentrations and muscle IGF-I mRNA levels also were significantly increased by seven days after implantation [8]. Additionally, approximately 50% more actively proliferating satellite cells were isolated from the semimembranosus muscles of E2/TBA implanted steers than from the same muscles of non-implanted, control steers [9]. Both the increased muscle IGF-I mRNA and increased satellite cell number may be significant in view of reports that virally induced over expression of IGF-I in muscle resulted in a 15% increase in muscle mass in young adult mice [10] and that IGF-I over expression extended the replicative lifespan of satellite cells in culture [11], [12].

E2 stimulates expression of IGF-I mRNA in a number of tissues [13], [14], [15], [16]. Studies evaluating the mechanism by which E2 stimulates expression of chicken IGF-I mRNA have shown that, even though the IGF-I gene does not contain a traditional estrogen response element (ERE) in its regulatory region, E2-stimulation of IGF-I mRNA expression can occur via a pathway involving the AP-1 enhancer [17]. In tissues studied to date, E2 stimulation of IGF-I mRNA expression is abrogated by treatment with the pure E2 antagonist ICI 182 780 [18], [19], [20]. However, the ability of E2 and/or agonists or antagonists to affect cellular responses via the AP-1 site varies dramatically with different cell types [21]. In addition to the classical estrogen receptors, G-protein-coupled receptor 30 (GRP30) [22], may play a role in mediating the actions of estrogen [23]. Muscle tissue contains GPR30 mRNA [24], [25], [26] and immunohistochemical studies have localized GPR30 receptor protein in skeletal muscle cells [27].

Androgen treatment also has been shown to increase IGF-I mRNA expression [16]. Recently, an androgen response element (ARE) has been identified in the promoter region of the IGF-I gene [28], suggesting that androgen receptor–ligand complex may interact with this ARE to stimulate transcription of the IGF-I gene.

We have previously shown that both E2 and TBA treatment cause a concentration-dependent increase in IGF-I mRNA expression by cultured bovine muscle satellite cells (BSC) [16]. Here, we have explored the mechanism responsible for this increase by evaluating the effects of ICI 182 780 (an estrogen receptor antagonist) and flutamide (an androgen receptor inhibitor) on E2 or TBA-stimulated IGF-I mRNA expression, respectively, in BSC cultures. Additionally, in order to determine if E2 must enter the cell in order to stimulate IGF-I mRNA expression and proliferation, we have examined the effects of BSA-conjugated E2 (which cannot cross the cell membrane) on IGF-I expression and proliferation in BSC cultures. We also have assessed the ability of the GPR30 agonist, G1 [29], to stimulate proliferation and IGF-I mRNA expression in BSC cultures.

Section snippets

Bovine satellite cell isolation

Satellite cell isolation was done as described previously [30], [31], [32]. Steers were euthanized using procedures approved by the Kansas State University Institutional Animal Care and Use Committee. Using sterile techniques, approximately 500 g of the semimembranosus muscle were dissected out and transported to the cell culture laboratory. Subsequent procedures were conducted in a sterile field under a tissue culture hood. After removal of connective tissue the muscle was passed through a

Effect of flutamide on TBA-stimulated IGF-I expression in BSC

We have previously shown that treatment of BSC cultures with 10 nM TBA for 48 h results in a significant increase in IGF-I mRNA expression [16]. Flutamide inhibits the action of the androgen receptor and consequently inhibits the action of androgens on cell function. Fig. 1 shows the effect of flutamide treatment on IGF-I mRNA expression in BSC cultures in the presence or absence of 10 nM TBA. Flutamide treatment has no effect on IGF-I mRNA expression in control cultures containing 10% FBS and no

Discussion

Studies in humans have shown that testosterone treatment increases IGF-I mRNA levels in skeletal muscle [43], [44]. Similarly, comparison of IGF-I mRNA levels in the splenius muscle of castrated and intact twin lambs showed higher levels of IGF-I mRNA in the muscle of intact sheep [45]. Recently, an androgen response element has been identified in the promoter region of the IGF-I gene [28], suggesting that androgen receptor–ligand complex may interact with this ARE to stimulate transcription of

Acknowledgements

This research was supported by National Research Initiative Competitive Grant 2006-35206-16663 from the USDA Cooperative State Research, Education, and Extension Service and by the Minnesota Agricultural Experiment Station.

References (49)

  • E. Kamanga-Sollo et al.

    Roles of IGF-I and the estrogen, androgen and IGF-I receptors in estradiol-17β and trenbolone acetate-stimulated proliferation of cultured bovine satellite cells

    Domest Anim Endocrinol

    (2008)
  • E. Kamanga-Sollo et al.

    Insulin-like growth factor binding protein (IGFBP)-3 and IGFBP-5 mediate TGF-beta- and myostatin-induced suppression of proliferation in porcine embryonic myogenic cell cultures

    Exp Cell Res

    (2005)
  • G. Xi et al.

    Effect of constitutive expression of porcine IGFBP-3 on proliferation and differentiation of L6 myogenic cells

    Domest Anim Endocrinol

    (2006)
  • L. Sahlin et al.

    Influence of blockers for the estrogen receptor (ER) and type 1 IGF-receptor on the levels of ER, ER mRNA and IGF-I mRNA in the rat uterus

    J Steroid Biochem Mol Biol

    (1996)
  • N. Kanda et al.

    17beta-estradiol stimulates the growth of human keratinocytes by inducing cyclin D2 expression

    J Invest Dermatol

    (2004)
  • D.W. Hunt et al.

    Use of trenbolone acetate and estradiol in intact and castrate male cattle: effects on growth, serum hormones, and carcass characteristics

    J Anim Sci

    (1991)
  • A.A. Ferrando et al.

    Testosterone administration to older men improves muscle function: molecular and physiological mechanisms

    Am J Physiol Endocrinol Metab

    (2002)
  • S. Bhasin et al.

    Testosterone dose-response relationships in healthy young men

    Am J Physiol Endocrinol Metab

    (2001)
  • S. Sipila et al.

    Effects of hormone replacement therapy and high-impact physical exercise on skeletal muscle in post-menopausal women: a randomized placebo-controlled study

    Clin Sci (Lond)

    (2001)
  • S. Sipila et al.

    Muscle performance, sex hormones and training in peri-menopausal and post-menopausal women

    Scand J Med Sci Sports

    (2003)
  • B.J. Johnson et al.

    Effect of a combined trenbolone acetate and estradiol implant on steroid hormone levels, feedlot performance, carcass characteristics and carcass composition of feedlot steers

    J Anim Sci

    (1996)
  • M.S. Pampusch et al.

    Time course of changes in growth factor mRNA levels in muscle of steroid-implanted and nonimplanted steers

    J Anim Sci

    (2003)
  • B.J. Johnson et al.

    Activation state of muscle satellite cells isolated from steers implanted with a combined trenbolone acetate and estradiol implant

    J Anim Sci

    (1998)
  • E.R. Barton-Davis et al.

    Viral mediated expression of insulin-like growth factor I blocks the aging-related loss of skeletal muscle function

    Proc Natl Acad Sci USA

    (1998)
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