Ayako Nakamura-Ishizu
   Department   School of Medicine, School of Medicine
   Position   Professor and Division head
Article types Original article
Language English
Peer review Peer reviewed
Title Mfsd2b is essential for the sphingosine-1-phosphate export in erythrocytes and platelets.
Journal Formal name:Nature
ISSN code:14764687/00280836
Domestic / ForeginForegin
Volume, Issue, Page 550(7677),pp.524-528
Author and coauthor Vu Thiet M, Ishizu Ayako-Nakamura, Foo Juat Chin, Toh Xiu Ru, Zhang Fangyu, Whee Ding Ming, Torta Federico, Cazenave-Gassiot Amaury, Matsumura Takayoshi, Kim Sangho, Toh Sue-Anne E S, Suda Toshio, Silver David L, Wenk Markus R, Nguyen Long N
Publication date 2017/10
Summary Sphingosine-1-phosphate (S1P), a potent signalling lipid secreted by red blood cells and platelets, plays numerous biologically significant roles. However, the identity of its long-sought exporter is enigmatic. Here we show that the major facilitator superfamily transporter 2b (Mfsd2b), an orphan transporter, is essential for S1P export from red blood cells and platelets. Comprehensive lipidomic analysis indicates a dramatic and specific accumulation of S1P species in Mfsd2b knockout red blood cells and platelets compared with that of wild-type controls. Consistently, biochemical assays from knockout red blood cells, platelets, and cell lines overexpressing human and mouse Mfsd2b proteins demonstrate that Mfsd2b actively exports S1P. Plasma S1P level in knockout mice is significantly reduced by 42-54% of that of wild-type level, indicating that Mfsd2b pathway contributes approximately half of the plasma S1P pool. The reduction of plasma S1P in knockout mice is insufficient to cause blood vessel leakiness, but it does render the mice more sensitive to anaphylactic shock. Stress-induced erythropoiesis significantly increased plasma S1P levels and knockout mice were sensitive to these treatments. Surprisingly, knockout mice exhibited haemolysis associated with red blood cell stomatocytes, and the haemolytic phenotype was severely increased with signs of membrane fragility under stress erythropoiesis. We show that S1P secretion by Mfsd2b is critical for red blood cell morphology. Our data reveal an unexpected physiological role of red blood cells in sphingolipid metabolism in circulation. These findings open new avenues for investigating the signalling roles of S1P derived from red blood cells and platelets.
DOI 10.1038/nature24053
PMID 29045386