Activation of insulin-like growth factor 1 receptor participates downstream of GPR30 in estradiol-17β-d-glucuronide-induced cholestasis in rats

Abstract

Estradiol-17β-D-glucuronide (E17G), through the activation of different signaling proteins, induces acute endocytic internalization of canalicular transporters in rat, including multidrug resistance-associated protein 2 (Abcc2) and bile salt export pump (Abcb11), generating cholestasis. Insulin-like growth factor 1 receptor (IGF-1R) is a membrane-bound tyrosine kinase receptor that can potentially interact with proteins activated by E17G. The aim of this study was to analyze the potential role of IGF-1R in the effects of E17G in isolated perfused rat liver (IPRL) and isolated rat hepatocyte couplets. In vitro, IGF-1R inhibition by tyrphostin AG1024 (TYR, 100 nM), or its knock-down with siRNA, strongly prevented E17G-induced impairment of Abcc2 and Abcb11 function and localization. The protection by TYR was not additive to that produced by wortmannin (PI3K inhibitor, 100 nM), and both protections share the same dependency on microtubule integrity, suggesting that IGF-1R shared the signaling pathway of PI3K/Akt. Further analysis of the activation of Akt and IGF-1R induced by E17G indicated a sequence of activation GPR30-IGF-1R-PI3K/Akt. In IPRL, an intraportal injection of E17G triggered endocytosis of Abcc2 and Abcb11, and this was accompanied by a sustained decrease in the bile flow and the biliary excretion of Abcc2 and Abcb11 substrates. TYR did not prevent the initial decay, but it greatly accelerated the recovery to normality of these parameters and the reinsertion of transporters into the canalicular membrane. In conclusion, the activation of IGF-1R is a key factor in the alteration of canalicular transporter function and localization induced by E17G, and its activation follows that of GPR30 and precedes that of PI3K/Akt.

Individualized medicine: Sex, hormones, genetics, and adverse drug reactions

“…Although some of the rapid effects observed could be attributed to antioxidant properties of the steroids, surface G‐coupled receptors (GPR30) that are independent of estrogen receptors but responsive to estrogen were identified as important in nongenomic estrogen signaling mechanisms . Estrogen receptors are ubiquitous with distribution in many cell types including hepatocytes . Activation of the GPR30 receptor and interaction with insulin‐like growth factor 1 receptor (ILG1R) initiates a cascade of activation of phosphatidyl inositol 3,4,5, triphosphate (PI3K)/Akt (serine‐threonine kinase) and mitogen‐activated protein kinases that has numerous intracellular effects, including promoting expression of Bc1‐2.…”

“…[26][27][28] Activation of the GPR30 receptor and interaction with insulin-like growth factor 1 receptor (ILG1R) initiates a cascade of activation of phosphatidyl inositol 3,4,5, triphosphate (PI3K)/Akt (serine-threonine kinase) and mitogen-activated protein kinases 24,25,29 that has numerous intracellular effects, including promoting expression of Bc1-2. Bc1-2 affects apoptosis, 26 endocytosis of canalicular transporters such as multidrug resistance-associated protein 2 (Abcc2) and bile salt export pump (Abcb11), 28 and synthesis of high-density lipoprotein cholesterol and liver fat in female but not male rats. 27 These same estrogen signaling pathways, if present in humans, may impact pharmacodynamic and/or pharmacokinetic pathways by altering similar physiologic processes, such as endocytosis of drug transporters.…”

“…[23][24][25] Estrogen receptors are ubiquitous with distribution in many cell types including hepatocytes. [26][27][28] Activation of the GPR30 receptor and interaction with insulin-like growth factor 1 receptor (ILG1R) initiates a cascade of activation of phosphatidyl inositol 3,4,5, triphosphate (PI3K)/Akt (serine-threonine kinase) and mitogen-activated protein kinases 24,25,29 that has numerous intracellular effects, including promoting expression of Bc1-2. Bc1-2 affects apoptosis, 26 endocytosis of canalicular transporters such as multidrug resistance-associated protein 2 (Abcc2) and bile salt export pump (Abcb11), 28 and synthesis of high-density lipoprotein cholesterol and liver fat in female but not male rats.…”

Regulation of ABC transporters by sex steroids may explain differences in drug resistance between sexes

“…Male C57BL/6 mice (8–9 weeks) treated with 17α-ethynylestradiol also showed a reduced mRNA and protein MRP2 expression in the liver when compared to control mice [ 77 ]. In rat hepatocytes, estradiol-17β- D -glucuronide, a 17β-estradiol endogenous metabolite, decreased the activity of MRP2, and also led to MRP2 internalization [ 6 , 10 ]. A study performed by Zucchetti et al .…”

“…In the same study, the pre-treatment with wortmannin, a PI3K inhibitor, TYR and with both compounds, partially abrogated the decrease in MRP2 activity induced by estradiol-17β- D -glucuronide. Thus, IGF-1R and PI3K are involved in the same pathway [ 6 ]. Another study with a different estrogenic compound reported that the administration of 17α-ethynylestradiol in the presence of LY294002, a PI3K inhibitor, reverted the effect induced by 17α-ethynylestradiol on MRP2 protein expression in rat’s liver [ 144 ].…”