The prognostic biomarker L-homoarginine is a substrate of the cationic amino acid transporters CAT1, CAT2A and CAT2B

Figures

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  Figure 1. Uptake of L-homoarginine (100 µmol/l) by HEK cells overexpressing CAT1 (HEK CAT1), CAT2A (HEK CAT2A), CAT2B (HEK CAT2B) and by the respective control cells (HEK VCG418 or HEK VCHygro). Each data point is n = 6, mean ± SEM. ***p < 0.001.

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  Figure 2. Time-dependent uptake of L-homoarginine in HEK cells overexpressing CAT1 (a), CAT2A (b) or CAT2B (c). Cells were incubated for 1, 2.5, 5, 10, and 30 min at 37 °C with 100 μM L-homoarginine. Each data point is n = 6. ***p < 0.001 as compared to suitable cells (HEK VCG418 or HEK VCHygro) containing only an empty vector.

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  Figure 3. CAT1- (a), CAT2A - (b) or CAT2B-mediated (c) uptake of L-homoarginine dependent of the L-homoarginine concentration. Each data point is n = 6.

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  Figure 4. Inhibition of CAT1-, CAT2A-, CAT2B-mediated L-homoarginine (100 µmol/l) uptake by increasing concentrations of L-arginine (a,c,e) and ADMA (b,d,f). Each data point is n = 6.

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  Figure 5. Inhibition of L-homoarginine uptake by HEK CAT1 cells and respective control cells (HEK VCG418) and resulting CAT1-mediated net uptake without and with co-administration of L-arginine in physiological concentrations. Each data point is n = 6, mean ± SEM, ***p < 0.001, **p < 0.01.

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  Figure 6. Inhibition of CAT1-, CAT2A-, CAT2B-mediated L-arginine (a,c,e) and ADMA (b,d,f) uptake by increasing concentrations of L-homoarginine. Each data point is n = 6.