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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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E2 and cAMP-PKA pathway regulated esr1, esr2a and esr2b expression time-dependently.Cultured follicle cells were co-treated with (A and B) forskolin (10 µM) and E2 (50 nM) or pretreated with (C and D) H89 (10 µM) for 15 min followed by treatment with E2 (50 nM) for 3 h or 24 h before the end of the 24-h treatment period. Quantification of mRNA of esr1, esr2a, esr2b and ef1a 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 = 4).
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pone-0062524-g003: E2 and cAMP-PKA pathway regulated esr1, esr2a and esr2b expression time-dependently.Cultured follicle cells were co-treated with (A and B) forskolin (10 µM) and E2 (50 nM) or pretreated with (C and D) H89 (10 µM) for 15 min followed by treatment with E2 (50 nM) for 3 h or 24 h before the end of the 24-h treatment period. Quantification of mRNA of esr1, esr2a, esr2b and ef1a 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 = 4).

Mentions: As shown in Fig. 3A, forskolin at 3 h reduced the expression of all three receptors in the presence or absence of E2 with the response of esr2a being the most prominent. E2 also slightly decreased esr2a expression in the presence or absence of forskolin. On the contrary, after 24-h treatment, forskolin significantly increased esr1 and esr2a expression and the effect on esr2a was slightly but significantly reduced by E2 (Fig. 3B).


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)

E2 and cAMP-PKA pathway regulated esr1, esr2a and esr2b expression time-dependently.Cultured follicle cells were co-treated with (A and B) forskolin (10 µM) and E2 (50 nM) or pretreated with (C and D) H89 (10 µM) for 15 min followed by treatment with E2 (50 nM) for 3 h or 24 h before the end of the 24-h treatment period. Quantification of mRNA of esr1, esr2a, esr2b and ef1a 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 = 4).
© Copyright Policy
Related In: Results  -  Collection

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

pone-0062524-g003: E2 and cAMP-PKA pathway regulated esr1, esr2a and esr2b expression time-dependently.Cultured follicle cells were co-treated with (A and B) forskolin (10 µM) and E2 (50 nM) or pretreated with (C and D) H89 (10 µM) for 15 min followed by treatment with E2 (50 nM) for 3 h or 24 h before the end of the 24-h treatment period. Quantification of mRNA of esr1, esr2a, esr2b and ef1a 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 = 4).
Mentions: As shown in Fig. 3A, forskolin at 3 h reduced the expression of all three receptors in the presence or absence of E2 with the response of esr2a being the most prominent. E2 also slightly decreased esr2a expression in the presence or absence of forskolin. On the contrary, after 24-h treatment, forskolin significantly increased esr1 and esr2a expression and the effect on esr2a was slightly but significantly reduced by E2 (Fig. 3B).

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