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Reactive gamma-ketoaldehydes as novel activators of hepatic stellate cells in vitro

Longato, L; Andreola, F; Davies, S; Roberts, JL; Fusai, G; Pinzani, M; Moore, K; (2016) Reactive gamma-ketoaldehydes as novel activators of hepatic stellate cells in vitro. Free Radical Biology and Medicine , 102 pp. 162-173. 10.1016/j.freeradbiomed.2016.11.036. Green open access

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Abstract

Aims: Products of lipid oxidation, such as 4-hydroxynonenal (4-HNE), are key activators of hepatic stellate cells (HSC) to a pro-fibrogenic phenotype. Isolevuglandins (IsoLG) are a family of acyclic γ-ketoaldehydes formed through oxidation of arachidonic acid or as by-products of the cyclooxygenase pathway. IsoLGs are highly reactive aldehydes which are efficient at forming protein adducts and cross-links at concentrations 100-fold lower than 4-hydroxynonenal. Since the contribution of IsoLGs to liver injury has not been studied, we synthesized 15-E2-IsoLG and used it to investigate whether IsoLG could induce activation of HSC. / Results: Primary human HSC were exposed to 15-E2-IsoLG for up to 48 hours. Exposure to 5 μM 15-E2-IsoLG in HSCs promoted cytotoxicity and apoptosis. At non-cytotoxic doses (50 pM-500 nM) 15-E2-IsoLG promoted HSC activation, indicated by increased expression of α-SMA, sustained activation of ERK and JNK signaling pathways, and increased mRNA and/or protein expression of cytokines and chemokines, which was blocked by inhibitors of JNK and NF-kB. In addition, IsoLG promoted formation of reactive oxygen species, and induced an early activation of ER stress, followed by autophagy. Inhibition of autophagy partially reduced the pro-inflammatory effects of IsoLG, suggesting that it might serve as a cytoprotective response. / Innovation: This study is the first to describe the biological effects of IsoLG in primary HSC, the main drivers of hepatic fibrosis. / Conclusions: IsoLGs represent a newly identified class of activators of HSC in vitro, which are biologically active at concentrations as low as 500 pM, and are particularly effective at promoting a pro-inflammatory response and autophagy.

Type: Article
Title: Reactive gamma-ketoaldehydes as novel activators of hepatic stellate cells in vitro
Open access status: An open access version is available from UCL Discovery
DOI: 10.1016/j.freeradbiomed.2016.11.036
Publisher version: http://dx.doi.org/10.1016/j.freeradbiomed.2016.11....
Language: English
Additional information: Copyright © 2016. This manuscript version is published under a Creative Commons Attribution Non-commercial Non-derivative 4.0 International licence (CC BY-NC-ND 4.0). This licence allows you to share, copy, distribute and transmit the work for personal and non-commercial use providing author and publisher attribution is clearly stated. Further details about CC BY licences are available at http://creativecommons.org/licenses/by/4.0. Access may be initially restricted by the publisher.
Keywords: Human hepatic stellate cells; fibrosis; isolevuglandins; isoketals; gamma-ketoaldehydes; inflammation; autophagy; endoplasmic reticulum stress; oxidative stress
UCL classification: UCL
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Medical Sciences
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Medical Sciences > Div of Medicine
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Medical Sciences > Div of Medicine > Department of Education
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Medical Sciences > Div of Medicine > Inst for Liver and Digestive Hlth
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Medical Sciences > Div of Surgery and Interventional Sci
URI: https://discovery.ucl.ac.uk/id/eprint/1529393
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