The equilibrative nucleoside transporter ENT1 is critical for nucleotide homeostasis and optimal erythropoiesis

Mahmoud Mikdar (1, 2) , Pedro González-Menéndez (2, 3) , Xiaoli Cai (4) , Yujin Zhang (4) , Marion Serra (1, 2) , Abdoul Dembele (1, 2) , Anne-Claire Boschat (5) , Sylvia Sanquer (6) , Cerina Chhuon (7) , Ida Chiara Guerrera (7) , Marc Sitbon (3) , Olivier Hermine (2, 8) , Yves Colin (1, 2) , Caroline Le van Kim (1, 2) , Sandrina Kinet (2, 3) , Narla Mohandas (9) , Yang Xia (4) , Thierry Peyrard (1, 2) , Naomi Taylor (3, 2, 10) , Slim Azouzi (1, 2)

1 BIGR (UMR_S_1134 / U1134) - Biologie Intégrée du Globule Rouge
2 Labex Gr-Ex - Laboratoire d'Excellence : Biogenèse et pathologies du globule rouge
3 Hematopoïèse et Immunothérapie
4 UTHealth - The University of Texas Health Science Center at Houston
5 Imagine - U1163 - Imagine - Institut des maladies génétiques (IHU)
6 T3S - UMR_S 1124 - Toxicité environnementale, cibles thérapeutiques, signalisation cellulaire
7 PPN - 3P5 - Plateforme Protéomique Necker [SFR Necker]
8 IADI - Imagerie Adaptative Diagnostique et Interventionnelle
9 New York Blood Center
10 NIH - National Institutes of Health [Bethesda, MD, USA]

The tight regulation of intracellular nucleotides is critical for the self-renewal and lineage specification of hematopoietic stem cells (HSCs). Nucleosides are major metabolite precursors for nucleotide biosynthesis and their availability in HSCs is dependent on their transport through specific membrane transporters. However, the role of nucleoside transporters in the differentiation of HSCs to the erythroid lineage and in red cell biology remains to be fully defined. Here, we show that the absence of the equilibrative nucleoside transporter (ENT1) in human red blood cells with a rare Augustine-null blood type is associated with macrocytosis, anisopoikilocytosis, an abnormal nucleotide metabolome, and deregulated protein phosphorylation. A specific role for ENT1 in human erythropoiesis was demonstrated by a defective erythropoiesis of human CD34+ progenitors following short hairpin RNA-mediated knockdown of ENT1. Furthermore, genetic deletion of ENT1 in mice was associated with reduced erythroid progenitors in the bone marrow, anemia, and macrocytosis. Mechanistically, we found that ENT1-mediated adenosine transport is critical for cyclic adenosine monophosphate homeostasis and the regulation of erythroid transcription factors. Notably, genetic investigation of 2 ENT1null individuals demonstrated a compensation by a loss-of-function variant in the ABCC4 cyclic nucleotide exporter. Indeed, pharmacological inhibition of ABCC4 in Ent1−/− mice rescued erythropoiesis. Overall, our results highlight the importance of ENT1-mediated nucleotide metabolism in erythropoiesis.

Domaines: Sciences du Vivant [q-bio]

Mahmoud Mikdar, Pedro González-Menéndez, Xiaoli Cai, Yujin Zhang, Marion Serra, et al.. The equilibrative nucleoside transporter ENT1 is critical for nucleotide homeostasis and optimal erythropoiesis. Blood, 2021, 137 (25), pp.3548-3562. ⟨10.1182/blood.2020007281⟩. ⟨hal-03423506⟩