Contributions
Abstract: EP1467
Type: ePoster
Abstract Category: Pathology and pathogenesis of MS - 13 Experimental models
Background: The multi-drug resistance transporter ABCG2, a member of the ATP-binding cassette (ABC) family, mediates the efflux of different immunotherapeutics, e.g. teriflunomide (teri) and mitoxantrone (MX), across cell membranes and organelles. Functional relevance of ABCG2 on MX-treatment was demonstrated in MS and its animal model, experimental autoimmune encephalomyelitis (EAE), but data are lacking for teri.
Apolipoprotein E (apoE) is known to have modulatory effects on ABC-transporter activity as demonstrated in experimental stroke. We therefore hypothesize that apoE affects teri-efficacy via abcg2-modulation.
Objective: To investigate effects of apoE-deficiency on abcg2-transporter expression and its functional impact on teri-induced cellular effects in vitro.
Methods: abcg2-mRNA expression (spleen/splenic T cells and B cells) from wildtype (wt) and apoE-/--mice were analyzed by qRT-PCR. Stimulated T cells from wt, apoE-/- and abcg2-/--mice (anti-CD3, 10µg/ml + anti-CD28, 10ng/ml; 48h) were treated with teri (12.5-100µM). T cell apoptosis (annexinV/PI) and proliferation (CSFE) were analyzed by flow cytometry.
Results: We observed a 1.8-fold (p=0.003) higher abcg2-mRNA expression in splenic T cells from apoE-/--mice compared to wt, which was not present in B cells (p=ns). Consistently, inhibition of T cell proliferation was 1.2-1.6-fold lower in apoE-/--mice than in wt (p< 0.05, 50-100µM teri, 48h). In line with the hypothesized effect of abcg2 on teri-efficacy, T cells from abcg2-/--mice revealed increased inhibitory effects of teri (1.3-1.9-fold increase compared to wt, p< 0.05, 12.5-100µM teri, 48h). Teri-induced T cell apoptosis as independent functional readout demonstrated analogous results (apoE-/-: 1.2-fold decrease, p< 0.01, 50µM teri and abcg2-/-: 1.2-fold increase, p< 0.05, 12.5µM teri; each compared to wt).
Conclusions: Our data indicates that regulation of abcg2-expression by apoE has functional effects on cellular effects of teri. This ongoing work aims at contributing to an understanding of inter-individual differences in efficacy and adverse events of prominent ABCG2-transporter substrates such as teri.
Disclosure:
LS received travel grants from Genzyme. KG former employee of Biogen, not related to this work. RH received research and travel grants from Novartis and Biogen Idec. AS received speaker honoraria and/or travel compensation for activities with Almirall Hermal GmbH, Biogen, Merck, Novartis, Roche and Sanofi Genzyme, none related to this work. DMH received speaker honoraria and consulting fees from Servier. FL received research grants from Teva and Genzyme. AC has received personal compensation and research support from Almirall, Bayer, Biogen, Genzyme, Merck, Novartis, Roche, Teva and UCB in the last 3 years. All other authors report no disclosures. This study is supported by Genzyme.
Abstract: EP1467
Type: ePoster
Abstract Category: Pathology and pathogenesis of MS - 13 Experimental models
Background: The multi-drug resistance transporter ABCG2, a member of the ATP-binding cassette (ABC) family, mediates the efflux of different immunotherapeutics, e.g. teriflunomide (teri) and mitoxantrone (MX), across cell membranes and organelles. Functional relevance of ABCG2 on MX-treatment was demonstrated in MS and its animal model, experimental autoimmune encephalomyelitis (EAE), but data are lacking for teri.
Apolipoprotein E (apoE) is known to have modulatory effects on ABC-transporter activity as demonstrated in experimental stroke. We therefore hypothesize that apoE affects teri-efficacy via abcg2-modulation.
Objective: To investigate effects of apoE-deficiency on abcg2-transporter expression and its functional impact on teri-induced cellular effects in vitro.
Methods: abcg2-mRNA expression (spleen/splenic T cells and B cells) from wildtype (wt) and apoE-/--mice were analyzed by qRT-PCR. Stimulated T cells from wt, apoE-/- and abcg2-/--mice (anti-CD3, 10µg/ml + anti-CD28, 10ng/ml; 48h) were treated with teri (12.5-100µM). T cell apoptosis (annexinV/PI) and proliferation (CSFE) were analyzed by flow cytometry.
Results: We observed a 1.8-fold (p=0.003) higher abcg2-mRNA expression in splenic T cells from apoE-/--mice compared to wt, which was not present in B cells (p=ns). Consistently, inhibition of T cell proliferation was 1.2-1.6-fold lower in apoE-/--mice than in wt (p< 0.05, 50-100µM teri, 48h). In line with the hypothesized effect of abcg2 on teri-efficacy, T cells from abcg2-/--mice revealed increased inhibitory effects of teri (1.3-1.9-fold increase compared to wt, p< 0.05, 12.5-100µM teri, 48h). Teri-induced T cell apoptosis as independent functional readout demonstrated analogous results (apoE-/-: 1.2-fold decrease, p< 0.01, 50µM teri and abcg2-/-: 1.2-fold increase, p< 0.05, 12.5µM teri; each compared to wt).
Conclusions: Our data indicates that regulation of abcg2-expression by apoE has functional effects on cellular effects of teri. This ongoing work aims at contributing to an understanding of inter-individual differences in efficacy and adverse events of prominent ABCG2-transporter substrates such as teri.
Disclosure:
LS received travel grants from Genzyme. KG former employee of Biogen, not related to this work. RH received research and travel grants from Novartis and Biogen Idec. AS received speaker honoraria and/or travel compensation for activities with Almirall Hermal GmbH, Biogen, Merck, Novartis, Roche and Sanofi Genzyme, none related to this work. DMH received speaker honoraria and consulting fees from Servier. FL received research grants from Teva and Genzyme. AC has received personal compensation and research support from Almirall, Bayer, Biogen, Genzyme, Merck, Novartis, Roche, Teva and UCB in the last 3 years. All other authors report no disclosures. This study is supported by Genzyme.