G-protein-coupled receptor 30/adenylyl cyclase/protein kinase A pathway is involved in estradiol 17ß-D-glucuronide-induced cholestasis
Fecha
2014-10
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Editor
Wiley
Resumen
Descripción
Estradiol-17ß-D-glucuronide (E17G) activates different signaling pathways (e.g., Ca21-
dependent protein kinase C, phosphoinositide 3-kinase/protein kinase B, mitogenactivated
protein kinases [MAPKs] p38 and extracellular signal-related kinase 1/2, and
estrogen receptor alpha) that lead to acute cholestasis in rat liver with retrieval of the
canalicular transporters, bile salt export pump (Abcb11) and multidrug resistanceassociated
protein 2 (Abcc2). E17G shares with nonconjugated estradiol the capacity to
activate these pathways. G-protein-coupled receptor 30 (GPR30) is a receptor implicated
in nongenomic effects of estradiol, and the aim of this study was to analyze the potential
role of this receptor and its downstream effectors in E17G-induced cholestasis. In
vitro, GPR30 inhibition by G15 or its knockdown with small interfering RNA strongly
prevented E17G-induced impairment of canalicular transporter function and localization.
E17G increased cyclic adenosine monophosphate (cAMP) levels, and this increase
was blocked by G15, linking GPR30 to adenylyl cyclase (AC). Moreover, AC inhibition
totally prevented E17G insult. E17G also increased protein kinase A (PKA) activity,
which was blocked by G15 and AC inhibitors, connecting the links of the pathway,
GPR30-AC-PKA. PKA inhibition prevented E17G-induced cholestasis, whereas exchange
protein activated directly by cyclic nucleotide/MAPK kinase, another cAMP downstream
effector, was not implicated in cAMP cholestatic action. In the perfused rat liver model,
inhibition of the GPR30-AC-PKA pathway totally prevented E17G-induced alteration in
Abcb11 and Abcc2 function and localization. Conclusion: In conclusion, activation of
GPR30-AC-PKA is a key factor in the alteration of canalicular transporter function and
localization induced by E17G. Interaction of E17G with GPR30 may be the first event
in the cascade of signaling activation.
Palabras clave
AC, Abcb11, Abcc2, GPR30, PKA, cAMP