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Evidence for gating roles of protein kinase A and protein kinase C in estradiol-induced luteinizing hormone receptor (lhcgr) expression in zebrafish ovarian follicle cells.

Liu KC, Ge W - PLoS ONE (2013)

Bottom Line: PKA inhibitor H89 showed reversed effects.In contrast, PKC pathway had consistent permissive effect on E2-induced lhcgr expression as evidenced by strong inhibition of E2 effect by PKC inhibitors GF109203X and Ro-31-8220 at both 3 and 24 h.One of the mechanisms by which PKA and PKC gated E2 effect might be through regulating nERs, particularly esr2a.

View Article: PubMed Central - PubMed

Affiliation: School of Life Sciences and Centre for Cell and Developmental Biology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China.

ABSTRACT
Estradiol (E2) stimulates luteinizing hormone receptor (lhcgr) expression in zebrafish follicle cells via nuclear estrogen receptors (nERs) that are likely expressed on the membrane, and lhcgr responds to E2 in a biphasic manner during 24-h treatment. These observations raise an interesting question on the signaling mechanism underlying E2 regulation, in particular the biphasic response of lhcgr expression. In the present study, we demonstrated that E2 regulation of lhcgr was significantly influenced by the activity of cAMP-PKA pathway. Activation of cAMP-PKA pathway by forskolin or db-cAMP suppressed E2-stimulated lhcgr expression in short-term (3 h) but enhanced its effect in long-term (24 h), suggesting differential roles of PKA at these two phases of lhcgr response. PKA inhibitor H89 showed reversed effects. In contrast, PKC pathway had consistent permissive effect on E2-induced lhcgr expression as evidenced by strong inhibition of E2 effect by PKC inhibitors GF109203X and Ro-31-8220 at both 3 and 24 h. One of the mechanisms by which PKA and PKC gated E2 effect might be through regulating nERs, particularly esr2a. Despite the strong influence of PKA and PKC, our data did not suggest direct mediating roles for these two pathways in E2 stimulation of lhcgr expression; yet they likely play critical gating roles in E2 signal transduction. As a follow-up study to our previous report on E2 regulation of gonadotropin receptors in the zebrafish ovary, the present study provides further evidence for the involvement of classical intracellular signal transduction pathways in E2 stimulation of lhcgr expression in the follicle cells.

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PKC pathway was crucial for nuclear estrogen receptor expression.The cultured follicle cells were pretreated with GF109203X (10 µM) or Ro-31-8220 (1 µM) for 15 min followed by treatment with E2 (50 nM) for 3 h (A and C) or 24 h (B and D) before the end of the 24-h treatment period. Quantification of mRNA level of esr1, esr2a and esr2b was carried out. The data were expressed as fold change compared to the control group after normalization to the expression of ef1a. Different letters in each data set indicated statistical significance (P<0.05; mean ± SEM, n = 3–4).
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pone-0062524-g007: PKC pathway was crucial for nuclear estrogen receptor expression.The cultured follicle cells were pretreated with GF109203X (10 µM) or Ro-31-8220 (1 µM) for 15 min followed by treatment with E2 (50 nM) for 3 h (A and C) or 24 h (B and D) before the end of the 24-h treatment period. Quantification of mRNA level of esr1, esr2a and esr2b was carried out. The data were expressed as fold change compared to the control group after normalization to the expression of ef1a. Different letters in each data set indicated statistical significance (P<0.05; mean ± SEM, n = 3–4).

Mentions: As shown in Fig. 7A, GF109203X significantly increased esr1 expression to approximately 2.5-fold, but suppressed the expression of both esr2a and esr2b to∼0.4-fold at 3 h in the presence or absence of E2. At 24 h, however, GF109203X suppressed the expression of all three nERs. The expression of esr1 decreased in contrast to its increase at 3 h, and the expression of esr2a expression further decreased to nearly undetectable level. Again, E2 had no effect on GF109203X-induced response of any nER (Fig. 7B). In agreement with GF109203X, another PKC inhibitor Ro-31-8220 also stimulated esr1 but reduced esr2a and esr2b expression at 3 h (Fig. 7C) while it tended to suppress all three nERs, especially esr2a, at 24 h (Fig. 7D).


Evidence for gating roles of protein kinase A and protein kinase C in estradiol-induced luteinizing hormone receptor (lhcgr) expression in zebrafish ovarian follicle cells.

Liu KC, Ge W - PLoS ONE (2013)

PKC pathway was crucial for nuclear estrogen receptor expression.The cultured follicle cells were pretreated with GF109203X (10 µM) or Ro-31-8220 (1 µM) for 15 min followed by treatment with E2 (50 nM) for 3 h (A and C) or 24 h (B and D) before the end of the 24-h treatment period. Quantification of mRNA level of esr1, esr2a and esr2b was carried out. The data were expressed as fold change compared to the control group after normalization to the expression of ef1a. Different letters in each data set indicated statistical significance (P<0.05; mean ± SEM, n = 3–4).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3643932&req=5

pone-0062524-g007: PKC pathway was crucial for nuclear estrogen receptor expression.The cultured follicle cells were pretreated with GF109203X (10 µM) or Ro-31-8220 (1 µM) for 15 min followed by treatment with E2 (50 nM) for 3 h (A and C) or 24 h (B and D) before the end of the 24-h treatment period. Quantification of mRNA level of esr1, esr2a and esr2b was carried out. The data were expressed as fold change compared to the control group after normalization to the expression of ef1a. Different letters in each data set indicated statistical significance (P<0.05; mean ± SEM, n = 3–4).
Mentions: As shown in Fig. 7A, GF109203X significantly increased esr1 expression to approximately 2.5-fold, but suppressed the expression of both esr2a and esr2b to∼0.4-fold at 3 h in the presence or absence of E2. At 24 h, however, GF109203X suppressed the expression of all three nERs. The expression of esr1 decreased in contrast to its increase at 3 h, and the expression of esr2a expression further decreased to nearly undetectable level. Again, E2 had no effect on GF109203X-induced response of any nER (Fig. 7B). In agreement with GF109203X, another PKC inhibitor Ro-31-8220 also stimulated esr1 but reduced esr2a and esr2b expression at 3 h (Fig. 7C) while it tended to suppress all three nERs, especially esr2a, at 24 h (Fig. 7D).

Bottom Line: PKA inhibitor H89 showed reversed effects.In contrast, PKC pathway had consistent permissive effect on E2-induced lhcgr expression as evidenced by strong inhibition of E2 effect by PKC inhibitors GF109203X and Ro-31-8220 at both 3 and 24 h.One of the mechanisms by which PKA and PKC gated E2 effect might be through regulating nERs, particularly esr2a.

View Article: PubMed Central - PubMed

Affiliation: School of Life Sciences and Centre for Cell and Developmental Biology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China.

ABSTRACT
Estradiol (E2) stimulates luteinizing hormone receptor (lhcgr) expression in zebrafish follicle cells via nuclear estrogen receptors (nERs) that are likely expressed on the membrane, and lhcgr responds to E2 in a biphasic manner during 24-h treatment. These observations raise an interesting question on the signaling mechanism underlying E2 regulation, in particular the biphasic response of lhcgr expression. In the present study, we demonstrated that E2 regulation of lhcgr was significantly influenced by the activity of cAMP-PKA pathway. Activation of cAMP-PKA pathway by forskolin or db-cAMP suppressed E2-stimulated lhcgr expression in short-term (3 h) but enhanced its effect in long-term (24 h), suggesting differential roles of PKA at these two phases of lhcgr response. PKA inhibitor H89 showed reversed effects. In contrast, PKC pathway had consistent permissive effect on E2-induced lhcgr expression as evidenced by strong inhibition of E2 effect by PKC inhibitors GF109203X and Ro-31-8220 at both 3 and 24 h. One of the mechanisms by which PKA and PKC gated E2 effect might be through regulating nERs, particularly esr2a. Despite the strong influence of PKA and PKC, our data did not suggest direct mediating roles for these two pathways in E2 stimulation of lhcgr expression; yet they likely play critical gating roles in E2 signal transduction. As a follow-up study to our previous report on E2 regulation of gonadotropin receptors in the zebrafish ovary, the present study provides further evidence for the involvement of classical intracellular signal transduction pathways in E2 stimulation of lhcgr expression in the follicle cells.

Show MeSH
Related in: MedlinePlus