Isoketals form cytotoxic phosphatidylethanolamine adducts in cells

Sullivan, Camille; Matafonova, Elena; Roberts, L. Jackson; Amarnath, Venkataraman; Davies, Sean S.

doi:10.1194/jlr.m001040

Cited by 51 publications

(79 citation statements)

References 29 publications

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“…In this view, IsoLG cytotoxicity could be the result of excessive accumulation of modified/adducted proteins [22]. Whilst this could also be the case for HSC, it must be noted that recent work has differentiated between the pathogenic role of IsoLG protein-and lipid-, particularly phosphatidylethanolamine, adducts [20,30,34]. Our experimental setup, based on the direct treatment with 15-E 2 -IsoLG, which may generate both types of adducts, does not allow us to attribute the observed effects solely to protein adducts and further studies will be necessary for a more precise definition in this sense.…”

Section: Discussionmentioning

confidence: 99%

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

Longato

Andreola

Davies

et al. 2017

Free Radical Biology and Medicine

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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 -ketoaldehydes formed through oxidation of arachidonic acid or as by-products of the cyclooxygenase pathway. IsoLGs are highly reactive aldehydes which are efficient at Longato 2 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-E 2 -IsoLG and used it to investigate whether IsoLG could induce activation of HSC. Results. Primary human HSC were exposed to 15-E 2 -IsoLG for up to 48 hours.Exposure to 5 M 15-E 2 -IsoLG in HSCs promoted cytotoxicity and apoptosis. At non-cytotoxic doses (50 pM-500 nM) 15-E 2 -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.

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Section: Discussionmentioning

confidence: 99%

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

Longato

Andreola

Davies

et al. 2017

Free Radical Biology and Medicine

Self Cite

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“…1-Palmitoyl-2-palmitoyl-sn -glycero-3-phosphoethanolamine (DPPE) and 1-palmitoyl-2-(12-[(7-nitro-2-1,3-benzoxadiazol-4-yl) amino]dodecanoyl)-sn -glycero-3-phosphoethanolamine (NBD-PE ) were purchased from Avanti Polar Lipids (Alabaster, AL IsoLG-Etn were synthesized as previously reported ( 8,9 ). NBD-NAPE was synthesized similarly using NBD-PE rather than DPPE.…”

Section: Methodsmentioning

confidence: 99%

“…4 ). We incubated this recombinant NAPE-PLD with synthetic IsoLG-PE for 1 h and assayed for the formation of IsoLG-Etn using our previously established MS assay (7)(8)(9). After 1 h incubation of IsoLG-PE with NAPE-PLD, we detected a large peak in the m/z 478 → 152 ion chromatograph corresponding to IsoLG-Etn ( Fig.…”

Section: Nape-pld Hydrolyzes Isolg-pe To Isolg-etnmentioning

confidence: 99%

“…We previously found that bacterial PLD rapidly hydrolyzed IsoLG-PE ( 8 ). We therefore considered the possibility that a mammalian PLD activity might also be responsible for IsoLG-PE hydrolysis.…”

Section: Silencing Nape-pld Inhibits Metabolism Of Isolg-pementioning

confidence: 99%

“…HEK293 cells or HUVECs were cultured and grown on 100 mm dishes to >90% confl uence as previously described ( 8,9 ). For studies examining stability of IsoLG-PE, cells were washed twice with HBSS, incubated with 1 M IsoLG in 10 ml HBSS for 1 h at 37°C to form IsoLG-PE, and then excess IsoLG removed by washing two times with DMEM.…”

Section: Cell Experimentsmentioning

confidence: 99%

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