Selective α1B- and α1D-adrenoceptor antagonists suppress noradrenaline-induced activation, proliferation and ECM secretion of rat hepatic stellate cells in vitro.

AIM:To explore the effects of noradrenaline (NA) on hepatic stellate cells (HSCs) in vitro and to determine the adrenoceptor (AR) subtypes and underlying mechanisms. METHODS:The distribution and expressions of α1A-, α1B-, and α1D-ARs in HSC-T6 cells were analyzed using immunocytochemistry and RT-PCR. Cell proliferation was evaluated with MTT assay. The expression of HSC activation factors [transforming factor-β1 (TGF-β1) and α-smooth muscle actin (α-SMA)], extracellular matrix (ECM) secretion factors [tissue inhibitor of metalloproteinase-1 (TIMP-1) and collagen-Ι (ColΙ)] and signaling components PI3K, and AKT) in the cells were detected by Western blotting and RT-PCR. RESULTS:Both α1B- and α1D-AR were expressed in the membrane of HSC-T6 cells, whereas α1A-AR was not detected. Treatment of the cells with NA concentration-dependently increased cell proliferation (EC50=277 nmol/L), which was suppressed by the α1B-AR antagonist CEC or by the α1D-AR antagonist BMY7378. Furthermore, NA (0.001, 0.1, and 10 μmol/L) concentration-dependently increased the expression of TGF-β1, α-SMA, TIMP-1 and ColΙ, and PI3K, and phosphorylation of AKT in HSC-T6 cells, which were suppressed by CEC or BMY7378, or by pertussis toxin (PT), RO-32-0432 antagonist), LY294002 (PI3K antagonist) or GSK690693 (AKT antagonist). CONCLUSION:NA promotes HSC-T6 cell activation, proliferation and secretion of ECM in vitro via activation of Gα-coupled α1B-AR and α1D-AR and the duanyu1531-PI3K-AKT signaling pathway.

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