Norepinephrine induces calcium spikes and proinflammatory actions in human hepatic stellate cells.
Catecholamines participate in the pathogenesis of portal hypertension and liver fibrosis through alpha1-adrenoceptors. However, the underlying cellular and molecular mechanisms are largely unknown. Here, we investigated the effects of norepinephrine (NE) on human hepatic stellate cells (HSC), which exert vasoactive, inflammatory, and fibrogenic actions in the injured liver. Adrenoceptor expression was assessed in human HSC by RT-PCR and immunocytochemistry. Intracellular Ca2+ concentration ([Ca2+]i) was studied in fura-2-loaded cells. Cell contraction was studied by assessing wrinkle formation and myosin light chain II (MLC II) phosphorylation. Cell proliferation and collagen-alpha1(I) expression were assessed by [3H]thymidine incorporation and quantitative PCR, respectively. NF-kappaB activation was assessed by luciferase reporter gene and p65 nuclear translocation. Chemokine secretion was assessed by ELISA. Normal human livers expressed alpha(1A)-adrenoceptors, which were markedly upregulated in livers with advanced fibrosis. Activated human HSC expressed alpha(1A)-adrenoceptors. NE induced multiple rapid [Ca2+]i oscillations (Ca2+ spikes). Prazosin (alpha1-blocker) completely prevented NE-induced Ca2+ spikes, whereas propranolol (nonspecific beta-blocker) partially attenuated this effect. NE caused phosphorylation of MLC II and cell contraction. In contrast, NE did not affect cell proliferation or collagen-alpha1(I) expression. Importantly, NE stimulated the secretion of inflammatory chemokines (RANTES and interleukin-8) in a dose-dependent manner. Prazosin blocked NE-induced chemokine secretion. NE stimulated NF-kappaB activation. BAY 11-7082, a specific NF-kappaB inhibitor, blocked NE-induced chemokine secretion. We conclude that NE stimulates NF-kappaB and induces cell contraction and proinflammatory effects in human HSC. Catecholamines may participate in the pathogenesis of portal hypertension and liver fibrosis by targeting HSC.
Sancho-Bru
Pau
P
Liver Unit, Institut Clínic de Malalties Digestives i Metabòliques, Hospital Clínic, Villarroel 170, Barcelona, Spain.
Bataller
Ramón
R
Colmenero
Jordi
J
Gasull
Xavier
X
Moreno
Montserrat
M
Arroyo
Vicente
V
Brenner
David A
DA
Ginès
Pere
P
D000256:Adenoviridae / Q000235:genetics; D015153:Blotting, Western; D020013:Calcium Signaling / Q000187:drug effects*; D049109:Cell Proliferation / Q000187:drug effects; D018925:Chemokines / Q000096:biosynthesis; D003094:Collagen / Q000096:biosynthesis; D024202:Electrophoretic Mobility Shift Assay; D005786:Gene Expression Regulation / Q000187:drug effects; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases / Q000235:genetics / Q000378:metabolism; D006801:Humans; D007249:Inflammation / Q000139:chemically induced / Q000378:metabolism*; D008099:Liver / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D008103:Liver Cirrhosis / Q000378:metabolism / Q000473:pathology; D016328:NF-kappa B / Q000378:metabolism; D009638:Norepinephrine / Q000494:pharmacology*; D012313:RNA / Q000096:biosynthesis / Q000235:genetics; D011941:Receptors, Adrenergic / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014162:Transfection; D015854:Up-Regulation
D018925:Chemokines; D016328:NF-kappa B; D011941:Receptors, Adrenergic; D012313:RNA; D003094:Collagen; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases; D009638:Norepinephrine