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Abstract
Platelets play a vital role in normal hemostasis to stem blood loss at sites of vascular injury by tethering and adhering to sites of injury, recruiting other platelets and blood cells to the developing clot, releasing vasoactive small molecules and proteins, and assembling and activating plasma coagulation proteins in a tightly regulated temporal and spatial manner. In synchrony with specific end products of coagulation, primarily cross-linked fibrin, a stable thrombus quickly forms. Far beyond physiological hemostasis and pathological thrombosis, emerging evidence supports platelets playing a pivotal role in vascular homeostasis, inflammation, cellular repair, regeneration, and wide range of autocrine and paracrine functions. In essence, platelets play both structural and functional roles as reporters, messengers, and active transporters surveying the vasculature for cues of environmental or developmental stimuli and participating as first responders.1 In this review, we will provide a contemporary perspective of platelet physiology, including fundamental, translational, and clinical constructs that apply directly to human health and disease.
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Affiliation(s)
- Richard C Becker
- From the Heart, Lung and Vascular Institute, University of Cincinnati College of Medicine, OH (R.C.B.); and Gill Heart and Vascular Institute (T.S., S.S.S.) and Lexington VA Medical Center (T.S., S.S.S.), University of Kentucky School of Medicine.
| | - Travis Sexton
- From the Heart, Lung and Vascular Institute, University of Cincinnati College of Medicine, OH (R.C.B.); and Gill Heart and Vascular Institute (T.S., S.S.S.) and Lexington VA Medical Center (T.S., S.S.S.), University of Kentucky School of Medicine
| | - Susan S Smyth
- From the Heart, Lung and Vascular Institute, University of Cincinnati College of Medicine, OH (R.C.B.); and Gill Heart and Vascular Institute (T.S., S.S.S.) and Lexington VA Medical Center (T.S., S.S.S.), University of Kentucky School of Medicine
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52
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Li F, Xu R, Low BE, Lin CL, Garcia-Barros M, Schrandt J, Mileva I, Snider A, Luo CK, Jiang XC, Li MS, Hannun YA, Obeid LM, Wiles MV, Mao C. Alkaline ceramidase 2 is essential for the homeostasis of plasma sphingoid bases and their phosphates. FASEB J 2018; 32:3058-3069. [PMID: 29401619 DOI: 10.1096/fj.201700445rr] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Sphingosine-1-phosphate (S1P) plays important roles in cardiovascular development and immunity. S1P is abundant in plasma because erythrocytes-the major source of S1P-lack any S1P-degrading activity; however, much remains unclear about the source of the plasma S1P precursor, sphingosine (SPH), derived mainly from the hydrolysis of ceramides by the action of ceramidases that are encoded by 5 distinct genes, acid ceramidase 1 ( ASAH1)/ Asah1, ASAH2/ Asah2, alkaline ceramidase 1 ( ACER1)/ Acer1, ACER2/ Acer2, and ACER3/ Acer3, in humans/mice. Previous studies have reported that knocking out Asah1 or Asah2 failed to reduce plasma SPH and S1P levels in mice. In this study, we show that knocking out Acer1 or Acer3 also failed to reduce the blood levels of SPH or S1P in mice. In contrast, knocking out Acer2 from either whole-body or the hematopoietic lineage markedly decreased the blood levels of SPH and S1P in mice. Of interest, knocking out Acer2 from whole-body or the hematopoietic lineage also markedly decreased the levels of dihydrosphingosine (dhSPH) and dihydrosphingosine-1-phosphate (dhS1P) in blood. Taken together, these results suggest that ACER2 plays a key role in the maintenance of high plasma levels of sphingoid base-1-phosphates-S1P and dhS1P-by controlling the generation of sphingoid bases-SPH and dhSPH-in hematopoietic cells.-Li, F., Xu, R., Low, B. E., Lin, C.-L., Garcia-Barros, M., Schrandt, J., Mileva, I., Snider, A., Luo, C. K., Jiang, X.-C., Li, M.-S., Hannun, Y. A., Obeid, L. M., Wiles, M. V., Mao, C. Alkaline ceramidase 2 is essential for the homeostasis of plasma sphingoid bases and their phosphates.
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Affiliation(s)
- Fang Li
- Department of Medicine, State University of New York at Stony Brook, Stony Brook, New York, USA.,Cancer Center, State University of New York at Stony Brook, Stony Brook, New York, USA.,Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Ruijuan Xu
- Department of Medicine, State University of New York at Stony Brook, Stony Brook, New York, USA.,Cancer Center, State University of New York at Stony Brook, Stony Brook, New York, USA
| | - Benjamin E Low
- Technology Evaluation and Development, The Jackson Laboratory, Bar Harbor, Maine, USA
| | - Chih-Li Lin
- Department of Medicine, State University of New York at Stony Brook, Stony Brook, New York, USA.,Cancer Center, State University of New York at Stony Brook, Stony Brook, New York, USA
| | - Monica Garcia-Barros
- Department of Medicine, State University of New York at Stony Brook, Stony Brook, New York, USA.,Cancer Center, State University of New York at Stony Brook, Stony Brook, New York, USA
| | - Jennifer Schrandt
- Department of Medicine, State University of New York at Stony Brook, Stony Brook, New York, USA.,Cancer Center, State University of New York at Stony Brook, Stony Brook, New York, USA
| | - Izolda Mileva
- Department of Medicine, State University of New York at Stony Brook, Stony Brook, New York, USA.,Cancer Center, State University of New York at Stony Brook, Stony Brook, New York, USA
| | - Ashley Snider
- Department of Medicine, State University of New York at Stony Brook, Stony Brook, New York, USA.,Cancer Center, State University of New York at Stony Brook, Stony Brook, New York, USA.,Northport Veterans Administration Medical Center, Northport, New York, USA
| | - Catherine K Luo
- Cancer Center, State University of New York at Stony Brook, Stony Brook, New York, USA
| | - Xian-Cheng Jiang
- Department of Cell Biology, State University of New York Downstate Medical Center, Brooklyn, New York, USA
| | - Ming-Song Li
- Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Yusuf A Hannun
- Department of Medicine, State University of New York at Stony Brook, Stony Brook, New York, USA.,Cancer Center, State University of New York at Stony Brook, Stony Brook, New York, USA
| | - Lina M Obeid
- Department of Medicine, State University of New York at Stony Brook, Stony Brook, New York, USA.,Cancer Center, State University of New York at Stony Brook, Stony Brook, New York, USA.,Northport Veterans Administration Medical Center, Northport, New York, USA
| | - Michael V Wiles
- Technology Evaluation and Development, The Jackson Laboratory, Bar Harbor, Maine, USA
| | - Cungui Mao
- Department of Medicine, State University of New York at Stony Brook, Stony Brook, New York, USA.,Cancer Center, State University of New York at Stony Brook, Stony Brook, New York, USA
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53
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YATOMI Y, KURANO M, IKEDA H, IGARASHI K, KANO K, AOKI J. Lysophospholipids in laboratory medicine. PROCEEDINGS OF THE JAPAN ACADEMY. SERIES B, PHYSICAL AND BIOLOGICAL SCIENCES 2018; 94:373-389. [PMID: 30541965 PMCID: PMC6374142 DOI: 10.2183/pjab.94.025] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Lysophospholipids (LPLs), such as lysophosphatidic acid (LPA), sphingosine 1-phosphate (S1P), and lysophosphatidylserine (LysoPS), are attracting attention as second-generation lipid mediators. In our laboratory, the functional roles of these lipid mediators and the mechanisms by which the levels of these mediators are regulated in vivo have been studied. Based on these studies, the clinical introduction of assays for LPLs and related proteins has been pursued and will be described in this review. Although assays of these lipids themselves are possible, autotaxin (ATX), apolipoprotein M (ApoM), and phosphatidylserine-specific phospholipase A1 (PS-PLA1) are more promising as alternate biomarkers for LPA, S1P, and LysoPS, respectively. Presently, ATX, which produces LPA through its lysophospholipase D activity, has been shown to be a useful laboratory test for the diagnosis and staging of liver fibrosis, whereas PS-PLA1 and ApoM are considered to be promising clinical markers reflecting the in vivo actions induced by LysoPS and S1P.
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Affiliation(s)
- Yutaka YATOMI
- Department of Clinical Laboratory Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
- Correspondence should be addressed: Y. Yatomi, Department of Clinical Laboratory Medicine, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan (e-mail: )
| | - Makoto KURANO
- Department of Clinical Laboratory Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Hitoshi IKEDA
- Department of Clinical Laboratory Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Koji IGARASHI
- Bioscience Division, TOSOH Corporation, Kanagawa, Japan
| | - Kuniyuki KANO
- Laboratory of Molecular and Cellular Biochemistry, Graduate School of Pharmaceutical Sciences, Tohoku University, Miyagi, Japan
| | - Junken AOKI
- Laboratory of Molecular and Cellular Biochemistry, Graduate School of Pharmaceutical Sciences, Tohoku University, Miyagi, Japan
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54
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Camerer E. Endotoxemia rocks sphingolipid metabolism at the blood-brain barrier: An Editorial Highlight for 'Alteration of sphingolipid metabolism as a putative mechanism underlying LPS-induced BBB disruption' on page 172. J Neurochem 2017; 144:115-117. [PMID: 29285771 DOI: 10.1111/jnc.14246] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Accepted: 10/18/2017] [Indexed: 11/28/2022]
Abstract
In this issue of the Journal of Neurochemistry, Vutukuri et al. evaluate the impact of endotoxemia-induced encephalopathy on the sphingosine-1-phosphate (S1P) signaling pathway at the blood-brain barrier (BBB). Four hours after intraperitoneal administration of lipopolysaccharides (LPS, 4 mg/kg) to mice, they first demonstrate BBB dysfunction and then evaluate changes in sphingolipid metabolites in serum, isolated brain microvessels (MBMV), and whole brain. In parallel, they investigate the fate of indicated S1P generating and metabolizing enzymes and S1P receptors in brain and MBMV. S1P levels decreased in serum and brain and a similar tendency was observed in MBMV. Sphk2 expression was strongly reduced in MBMV together with an up-regulation of lipid phosphate and S1P phosphatases, resulting in a net decrease in S1P levels despite a compensatory increase in Sphk1 expression. The implications of disturbed sphingolipid metabolism for the pathogenesis of septic encephalopathy will depend on the net impact of these changes on S1P receptor signaling at the BBB and the importance of the S1P pathway in regulating vascular homeostasis in this context.
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Affiliation(s)
- Eric Camerer
- INSERM U970, Paris Cardiovascular Research Center, Paris, France.,Université Paris-Descartes, Paris, France
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55
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Platelets and vascular integrity: how platelets prevent bleeding in inflammation. Blood 2017; 131:277-288. [PMID: 29191915 DOI: 10.1182/blood-2017-06-742676] [Citation(s) in RCA: 105] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Accepted: 11/13/2017] [Indexed: 02/07/2023] Open
Abstract
Platelets play a central role in primary hemostasis by forming aggregates that plug holes in injured vessels. Half a century ago, detailed studies of the microvasculature by electron microscopy revealed that under inflammatory conditions that do not induce major disruption to vascular structure, individual platelets are mobilized to the vessel wall, where they interact with leukocytes and appear to seal gaps that arise between endothelial cells. Recent developments in genetic engineering and intravital microscopy have allowed further molecular and temporal characterization of these events. Surprisingly, it turns out that platelets support the recruitment of leukocytes to sites of inflammation. In parallel, however, they exercise their hemostatic function by securing the integrity of inflamed blood vessels to prevent bleeding from sites of leukocyte infiltration. It thus appears that platelets not only serve in concert as building blocks of the hemostatic plug but also act individually as gatekeepers of the vascular wall to help preserve vascular integrity while coordinating host defense. Variants of this recently appreciated hemostatic function of platelets that we refer to as "inflammation-associated hemostasis" are engaged in different contexts in which the endothelium is challenged or dysfunctional. Although the distinguishing characteristics of these variants and the underlying mechanisms of inflammation-associated hemostasis remain to be fully elucidated, they can differ notably from those supporting thrombosis, thus presenting therapeutic opportunities.
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56
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Vu TM, Ishizu AN, Foo JC, Toh XR, Zhang F, Whee DM, Torta F, Cazenave-Gassiot A, Matsumura T, Kim S, Toh SAES, Suda T, Silver DL, Wenk MR, Nguyen LN. Mfsd2b is essential for the sphingosine-1-phosphate export in erythrocytes and platelets. Nature 2017; 550:524-528. [PMID: 29045386 DOI: 10.1038/nature24053] [Citation(s) in RCA: 165] [Impact Index Per Article: 23.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Accepted: 08/31/2017] [Indexed: 12/28/2022]
Abstract
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.
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Affiliation(s)
- Thiet M Vu
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, 5 Medical Drive, Singapore 117545
| | - Ayako-Nakamura Ishizu
- Cancer Science Institute, Yong Loo Lin School of Medicine, National University of Singapore, 14 Medical Drive, Singapore 117599
| | - Juat Chin Foo
- Singapore Lipidomics Incubator (SLING), Life Sciences Institute, National University of Singapore, 28 Medical Drive, Singapore 117456
| | - Xiu Ru Toh
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, 5 Medical Drive, Singapore 117545
| | - Fangyu Zhang
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, 5 Medical Drive, Singapore 117545
| | - Ding Ming Whee
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, 5 Medical Drive, Singapore 117545
| | - Federico Torta
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, 5 Medical Drive, Singapore 117545.,Singapore Lipidomics Incubator (SLING), Life Sciences Institute, National University of Singapore, 28 Medical Drive, Singapore 117456
| | - Amaury Cazenave-Gassiot
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, 5 Medical Drive, Singapore 117545.,Singapore Lipidomics Incubator (SLING), Life Sciences Institute, National University of Singapore, 28 Medical Drive, Singapore 117456
| | - Takayoshi Matsumura
- Cancer Science Institute, Yong Loo Lin School of Medicine, National University of Singapore, 14 Medical Drive, Singapore 117599
| | - Sangho Kim
- Department of Biomedical Engineering, National University of Singapore, 4 Engineering Drive 3, Singapore 117583.,Biomedical Institute for Global Health Research and Technology, National University of Singapore, 14 Medical Drive, Singapore 117599.,NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, 28 Medical Drive, Singapore 117456
| | - Sue-Anne E S Toh
- Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117599
| | - Toshio Suda
- Cancer Science Institute, Yong Loo Lin School of Medicine, National University of Singapore, 14 Medical Drive, Singapore 117599
| | - David L Silver
- Signature Research Program in Cardiovascular & Metabolic Disorders, Duke-NUS Medical School, 8 College Road, Singapore 169857
| | - Markus R Wenk
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, 5 Medical Drive, Singapore 117545.,Singapore Lipidomics Incubator (SLING), Life Sciences Institute, National University of Singapore, 28 Medical Drive, Singapore 117456
| | - Long N Nguyen
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, 5 Medical Drive, Singapore 117545
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57
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Mendelson K, Pandey S, Hisano Y, Carellini F, Das BC, Hla T, Evans T. The ceramide synthase 2b gene mediates genomic sensing and regulation of sphingosine levels during zebrafish embryogenesis. eLife 2017; 6:21992. [PMID: 28956531 PMCID: PMC5650468 DOI: 10.7554/elife.21992] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Accepted: 09/25/2017] [Indexed: 12/23/2022] Open
Abstract
Sphingosine-1-phosphate (S1P) is generated through phosphorylation of sphingosine by sphingosine kinases (Sphk1 and Sphk2). We show that sphk2 maternal-zygotic mutant zebrafish embryos (sphk2MZ) display early developmental phenotypes, including a delay in epiboly, depleted S1P levels, elevated levels of sphingosine, and resistance to sphingosine toxicity. The sphk2MZ embryos also have strikingly increased levels of maternal transcripts encoding ceramide synthase 2b (Cers2b), and loss of Cers2b in sphk2MZ embryos phenocopies sphingosine toxicity. An upstream region of the cers2b promoter supports enhanced expression of a reporter gene in sphk2MZ embryos compared to wildtype embryos. Furthermore, ectopic expression of Cers2b protein itself reduces activity of the promoter, and this repression is relieved by exogenous sphingosine. Therefore, the sphk2MZ genome recognizes the lack of sphingosine kinase activity and up-regulates cers2b as a salvage pathway for sphingosine turnover. Cers2b can also function as a sphingolipid-responsive factor to mediate at least part of a feedback regulatory mechanism.
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Affiliation(s)
- Karen Mendelson
- Department of Surgery, Weill Cornell Medical College, Cornell University, New York, United States.,Center for Vascular Biology, Department of Pathology and Laboratory Medicine, Weill Cornell Medical College, Cornell University, New York, United States
| | - Suveg Pandey
- Department of Surgery, Weill Cornell Medical College, Cornell University, New York, United States
| | - Yu Hisano
- Vascular Biology Program, Department of Surgery, Boston Children's Hospital, Boston, United States.,Harvard Medical School, Boston, United States
| | - Frank Carellini
- Department of Surgery, Weill Cornell Medical College, Cornell University, New York, United States
| | - Bhaskar C Das
- Department of Medicine, Division of Nephrology, Icahn School of Medicine at Mount Sinai, New York, United States
| | - Timothy Hla
- Vascular Biology Program, Department of Surgery, Boston Children's Hospital, Boston, United States.,Harvard Medical School, Boston, United States
| | - Todd Evans
- Department of Surgery, Weill Cornell Medical College, Cornell University, New York, United States
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