Iron Enhances Hepatic Fibrogenesis and Activates Transforming Growth Factor-β Signaling in Murine Hepatic Stellate Cells.
Mehta, K, Coombes, JD, Briones-Orta, M, Manka, PP, Williams, R, Patel, VB and Syn, W-K (2018). Iron Enhances Hepatic Fibrogenesis and Activates Transforming Growth Factor-β Signaling in Murine Hepatic Stellate Cells. American Journal of the Medical Sciences. 355 (2), pp. 183-190.
|Authors||Mehta, K, Coombes, JD, Briones-Orta, M, Manka, PP, Williams, R, Patel, VB and Syn, W-K|
BACKGROUND: Although excess iron induces oxidative stress in the liver, it is unclear whether it directly activates the hepatic stellate cells (HSC). MATERIALS AND METHODS: We evaluated the effects of excess iron on fibrogenesis and transforming growth factor beta (TGF-β) signaling in murine HSC. Cells were treated with holotransferrin (0.005-5g/L) for 24 hours, with or without the iron chelator deferoxamine (10µM). Gene expressions (α-SMA, Col1-α1, Serpine-1, TGF-β, Hif1-α, Tfrc and Slc40a1) were analyzed by quantitative real time-polymerase chain reaction, whereas TfR1, ferroportin, ferritin, vimentin, collagen, TGF-β RII and phospho-Smad2 proteins were evaluated by immunofluorescence, Western blot and enzyme-linked immunosorbent assay. RESULTS: HSC expressed the iron-uptake protein transferrin receptor 1 (TfR1) and the iron-export protein ferroportin. Holotransferrin upregulated TfR1 expression by 1.8-fold (P < 0.03) and ferritin accumulation (iron storage) by 2-fold (P < 0.01), and activated HSC with 2-fold elevations (P < 0.03) in α-SMA messenger RNA and collagen secretion, and a 1.6-fold increase (P < 0.01) in vimentin protein. Moreover, holotransferrin activated the TGF-β pathway with TGF-β messenger RNA elevated 1.6-fold (P = 0.05), and protein levels of TGF-β RII and phospho-Smad2 increased by 1.8-fold (P < 0.01) and 1.6-fold (P < 0.01), respectively. In contrast, iron chelation decreased ferritin levels by 30% (P < 0.03), inhibited collagen secretion by 60% (P < 0.01), repressed fibrogenic genes α-SMA (0.2-fold; P < 0.05) and TGF-β (0.4-fold; P < 0.01) and reduced levels of TGF-β RII and phospho-Smad2 proteins. CONCLUSIONS: HSC express iron-transport proteins. Holotransferrin (iron) activates HSC fibrogenesis and the TGF-β pathway, whereas iron depletion by chelation reverses this, suggesting that this could be a useful adjunct therapy for patients with fibrosis. Further studies in primary human HSC and animal models are necessary to confirm this.
|Keywords||Cell Line; Animals; Mice; Liver Cirrhosis; Iron; Protein-Serine-Threonine Kinases; Transforming Growth Factor beta; Receptors, Transferrin; Receptors, Transforming Growth Factor beta; RNA, Messenger; Signal Transduction; Gene Expression Regulation; Smad2 Protein; Ferritins; Hepatic Stellate Cells; Fibroblasts; Fibrosis; Holotransferrin; Liver; Animals; Cell Line; Ferritins; Gene Expression Regulation; Hepatic Stellate Cells; Iron; Liver Cirrhosis; Mice; Protein-Serine-Threonine Kinases; RNA, Messenger; Receptors, Transferrin; Receptors, Transforming Growth Factor beta; Signal Transduction; Smad2 Protein; Transforming Growth Factor beta; 11 Medical And Health Sciences; General & Internal Medicine|
|Journal||American Journal of the Medical Sciences|
|Journal citation||355 (2), pp. 183-190|
|Digital Object Identifier (DOI)||doi:10.1016/j.amjms.2017.08.012|
|01 Feb 2018|
|Publication process dates|
|Deposited||12 Nov 2018|
|Accepted||21 Aug 2017|
|Accepted author manuscript|
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