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Abstract: TH-PO364

Tenofovir Alafenamide Fumarate (TAF) and Tenofovir (TFV) Have a Different Impact on the Proteome of Proximal Tubular Cells (PTCs)

Session Information

Category: Pharmacology (PharmacoKinetics, -Dynamics, -Genomics)

  • 1800 Pharmacology (PharmacoKinetics, -Dynamics, -Genomics)

Authors

  • Aouad, Hassan, INSERM, UMR 1248 IPPRITT, University of Limoges, Limoges, France
  • Burat, Bastien, INSERM, UMR 1248 IPPRITT, University of Limoges, Limoges, France
  • Sauvage, François-Ludovic, INSERM, UMR 1248 IPPRITT, University of Limoges, Limoges, France
  • Essig, Marie, APHP, Boulogne Billancourt, France
Background

TAF, a new produg of TFV was developed to be less nephrotoxic than Tenofovir Desproxil Fumarate (TDF), by releasing less TFV in the blood. First clinical studies confirmed the low renal toxicity of TAF. However, TAF and TFV respective effects on renal tubular cells have never been compared. The aim of this study was to study the effects of TFV, TAF and ABC (as control nucleosidic inhibitor) on PTC .

Methods

iTRAQ differential proteomic strategy was used to analyse the effects of TFV (287 ng/mL ), TAF (215 ng/mL), ABC (4200 ng/mL) or vehicle (water) on LLC-PK1. Cells were exposed for 24h to the different drugs before protein extraction. After proteins digestion by trypsin, peptides were tagged with iTRAQ reagents, then seperated into 12 different fractions by isoelectrofucusing. Generated fractions were analysed using triple TOF 5600+ mass spectrometer (ABSciex).

Results

One hundred sixty-nine proteins were identified in all 5 independent experiments. Among them, 17 were modified by TFV (11 up-regulated and 6 down-regulated), 21 by TAF (10 up-regulated and 11 down regulated) and 17 by ABC (9 up-regulated and 8 down-regulated). Only few proteins were similarly modified by the 3 drugs. ATP synthase-coupling factor 6 and Electron transfer flavoprotein-ubiquinone oxidoreductase were reduced by the 3 drugs whereas testin was increased. TAF and TFV commonly affect the expression of Ras-related protein Rab-1A, U1 small nuclear ribonucleoprotein A, and alter in opposite way the expression of Thymosin beta-10, Polypyrimidine tract-binding protein 1. TFV specifically increased 5 proteins and decreased 3 proteins among them the V-type proton ATPase catalytic subunit A, which is involved in the acidification of cytoplasmic vesicles during membrane trafficking. TAF alone decreased 5 proteins and increased 7 proteins among them megalin, the major protein involved in endocytosis in PTC.

Conclusion

Our results confirmed the different impact of TFV, TAF and ABC on PTC. If the 3 drugs modified the electron chain transport explaining their potential mitochondrial toxicity, TFV seemed to negatively affect the endocytic capacity of PTC whereas TAF may maintain it through the upregulation of megalin. These results are in accordance with clinical data showing a decrease in tubular proteinuria after the switch from TDF to TAF.