Arteriosclerosis, Thrombosis, & Vascular Biology最新文献

{"title":"Effects of Replacing Dietary Monounsaturated Fat With Carbohydrate on HDL (High-Density Lipoprotein) Protein Metabolism and Proteome Composition in Humans.","authors":"Allison B. Andraski, Sasha A. Singh, L. Lee, Hideyuki Higashi, Nathaniel Smith, Bo Zhang, M. Aikawa, F. Sacks","doi":"10.1161/ATVBAHA.119.312889","DOIUrl":"https://doi.org/10.1161/ATVBAHA.119.312889","url":null,"abstract":"OBJECTIVE\u0000Clinical evidence has linked low-HDL (high-density lipoprotein) cholesterol levels with high cardiovascular disease risk; however, its significance as a therapeutic target remains unestablished. We hypothesize that HDLs functional heterogeneity is comprised of metabolically distinct proteins, each on distinct HDL sizes and that are affected by diet. Approach and Results: Twelve participants were placed on 2 healthful diets high in monounsaturated fat or carbohydrate. After 4 weeks on each diet, participants completed a metabolic tracer study. HDL was isolated by Apo (apolipoprotein) A1 immunopurification and separated into 5 sizes. Tracer enrichment and metabolic rates for 8 HDL proteins-ApoA1, ApoA2, ApoC3, ApoE, ApoJ, ApoL1, ApoM, and LCAT-were determined by parallel reaction monitoring and compartmental modeling, respectively. Each protein had a unique, size-specific distribution that was not altered by diet. However, carbohydrate, when replacing fat, increased the fractional catabolic rate of ApoA1 and ApoA2 on alpha3 HDL; ApoE on alpha3 and alpha1 HDL; and ApoM on alpha2 HDL. Additionally, carbohydrate increased the production of ApoC3 on alpha3 HDL and ApoJ and ApoL1 on the largest alpha0 HDL. LCAT (lecithin-cholesterol acyltransferase) was the only protein studied that diet did not affect. Finally, global proteomics showed that diet did not alter the distribution of the HDL proteome across HDL sizes.\u0000\u0000\u0000CONCLUSIONS\u0000This study demonstrates that HDL in humans is composed of a complex system of proteins, each with its own unique size distribution, metabolism, and diet regulation. The carbohydrate-induced hypercatabolic state of HDL proteins may represent mechanisms by which carbohydrate alters the cardioprotective properties of HDL.","PeriodicalId":8404,"journal":{"name":"Arteriosclerosis, Thrombosis, & Vascular Biology","volume":"7 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91501433","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"C-X-C Ligand 16 Is an Independent Predictor of Cardiovascular Death and Morbidity in Acute Coronary Syndromes.","authors":"T. Andersen, T. Ueland, T. Ghukasyan Lakic, A. Åkerblom, M. Bertilsson, P. Aukrust, A. Michelsen, S. James, R. Becker, R. Storey, L. Wallentin, A. Siegbahn, F. Kontny","doi":"10.1161/ATVBAHA.119.312633","DOIUrl":"https://doi.org/10.1161/ATVBAHA.119.312633","url":null,"abstract":"OBJECTIVE\u0000The CXCL16 (chemokine C-X-C motif ligand 16) is a scavenger receptor for OxLDL (oxidized low-density lipoproteins) and involved in inflammation at sites of atherosclerosis. This study aimed to investigate the association of CXCL16 with clinical outcome in patients with acute coronary syndrome. Approach and Results: Serial measurements of CXCL16 were performed in a subgroup of 5142 patients randomized in the PLATO trial (Platelet Inhibition and Patient Outcome). Associations between CXCL16 and a composite of cardiovascular death, spontaneous myocardial infarction or stroke, and the individual components were assessed by multivariable Cox regression analyses. The hazard ratio per 50% increase in admission levels of CXCL16 analyzed as continuous variable was 1.64 (95% CI, 1.44-1.88), P<0.0001. This association remained statistically significant after adjustment for randomized treatment, clinical variables, CRP (C-reactive protein), leukocytes, cystatin C, NT-proBNP (N-terminal pro-brain natriuretic peptide), troponin T, GDF-15 (growth differentiation factor 15), and other biomarkers; hazard ratio 1.23 (1.05-1.45), P=0.0126. The admission level of CXCL16 was independently associated with cardiovascular death (1.50 [1.17-1.92], P=0.0014) but not with ischemic events alone, in fully adjusted analyses. No statistically independent association was found between CXCL16 measured at 1 month, or change in CXCL16 from admission to 1 month, and clinical outcomes.\u0000\u0000\u0000CONCLUSIONS\u0000In patients with acute coronary syndrome, admission level of CXCL16 is independently related to adverse clinical outcomes, mainly driven by an association to cardiovascular death. Thus, CXCL16 measurement may enhance risk stratification in patients with this condition.\u0000\u0000\u0000CLINICAL TRIAL REGISTRATION\u0000URL: http://www.clinicaltrials.gov. Unique identifier: NCT00391872.","PeriodicalId":8404,"journal":{"name":"Arteriosclerosis, Thrombosis, & Vascular Biology","volume":"105 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75214984","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"VWF (von Willebrand Factor) Comes in From the Cold As a Strategy to Improve Platelet Storage.","authors":"J. Emsley","doi":"10.1161/ATVBAHA.119.313069","DOIUrl":"https://doi.org/10.1161/ATVBAHA.119.313069","url":null,"abstract":"The interaction between platelet GPIb (glycoprotein Ib) and VWF (von Willebrand factor) is essential for blood hemostasis and occurs when VWF is bound to damaged subendothelium representing the first step in platelet adhesion. The interaction is mediated between the N-terminal domain of GPIb and the VWF A1 domain and does not normally occur under static conditions requiring high hydrodynamic shear stress to stimulate the binding by unfolding VWF. In clinical settings where the hemostatic system needs a boost such as hemorrhage or low platelet counts (thrombocytopenia) transfusion of platelets is a desirable therapeutic option. However, storing platelets for transfusion at room temperature presents a problem as there is an increased risk of microbial infection. Thus, refrigerated platelet storage is a superior alternative, but cold treatment leads to rapid platelet clearance after transfusion. Recent studies from the group of Renhao Li using a variety of approaches confirmed the findings from previous work1,2 showing the importance of the GPIb receptor as a driver of cold platelet clearance.3 In addition, they implicated the interaction with ligand (VWF) as making a significant contribution to the clearance mechanism.3 The same group then reported that the OS1 (optimized sequence 1) peptide, which binds to GPIb, and is a highly selective and potent inhibitor of the interaction with VWF when added during platelet refrigeration improved the recovery and survival of platelets.4","PeriodicalId":8404,"journal":{"name":"Arteriosclerosis, Thrombosis, & Vascular Biology","volume":"109 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75626121","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Revisiting Vascular Remodeling in the Single-Cell Transcriptome Era.","authors":"Jifeng Zhang, Lin Chang, M. Garcia-Barrio, Y. E. Chen","doi":"10.1161/ATVBAHA.119.313174","DOIUrl":"https://doi.org/10.1161/ATVBAHA.119.313174","url":null,"abstract":"Correspondence to: Jifeng Zhang, PhD, Frankel Cardiovascular Center, Department of Internal Medicine, University of Michigan Medical Center, NCRC Bldg 26, Room 357S 2800 Plymouth Rd, Ann Arbor, MI 48109, Email jifengz@umich.edu; or Y. Eugene Chen, MD, PhD, Frankel Cardiovascular Center, Department of Internal Medicine, University of Michigan Medical Center, NCRC Bldg 26, Room 361S 2800 Plymouth Rd, Ann Arbor, MI 48109, Email echenum@umich.edu","PeriodicalId":8404,"journal":{"name":"Arteriosclerosis, Thrombosis, & Vascular Biology","volume":"2 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79944480","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Coronary Artery Disease Risk-Associated Plpp3 Gene and Its Product Lipid Phosphate Phosphatase 3 Regulate Experimental Atherosclerosis.","authors":"P. Mueller, Liping Yang, Margo F. Ubele, Guogen Mao, J. Brandon, Julia Vandra, T. Nichols, D. Escalante-Alcalde, A. Morris, S. Smyth","doi":"10.1161/ATVBAHA.119.313056","DOIUrl":"https://doi.org/10.1161/ATVBAHA.119.313056","url":null,"abstract":"OBJECTIVE\u0000Genome-wide association studies identified novel loci in PLPP3 (phospholipid phosphatase 3) that associate with coronary artery disease risk independently of traditional risk factors. PLPP3 encodes LPP3 (lipid phosphate phosphatase 3), a cell-surface enzyme that can regulate the availability of bioactive lysophopsholipids including lysophosphatidic acid (LPA). The protective allele of PLPP3 increases LPP3 expression during cell exposure to oxidized lipids, however, the role of LPP3 in atherosclerosis remains unclear. Approach and Results: In this study, we sought to validate LPP3 as a determinate of the development of atherosclerosis. In experimental models of atherosclerosis, LPP3 is upregulated and co-localizes with endothelial, smooth muscle cell, and CD68-positive cell markers. Global post-natal reductions in Plpp3 expression in mice substantially increase atherosclerosis, plaque-associated LPA, and inflammation. Although LPP3 expression increases during ox-LDL (oxidized low-density lipoprotein)-induced phenotypic modulation of bone marrow-derived macrophages, myeloid Plpp3 does not appear to regulate lesion formation. Rather, smooth muscle cell LPP3 expression is a critical regulator of atherosclerosis and LPA content in lesions. Moreover, mice with inherited deficiency in LPA receptor signaling are protected from experimental atherosclerosis.\u0000\u0000\u0000CONCLUSIONS\u0000Our results identify a novel lipid signaling pathway that regulates inflammation in the context of atherosclerosis and is not related to traditional risk factors. Pharmacological targeting of bioactive LPP3 substrates, including LPA, may offer an orthogonal approach to lipid-lowering drugs for mitigation of coronary artery disease risk.","PeriodicalId":8404,"journal":{"name":"Arteriosclerosis, Thrombosis, & Vascular Biology","volume":"74 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86143303","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Endothelial β-Catenin Signaling Supports Postnatal Brain and Retinal Angiogenesis by Promoting Sprouting, Tip Cell Formation, and VEGFR (Vascular Endothelial Growth Factor Receptor) 2 Expression.","authors":"A. Martowicz, Marta Trusohamn, Nina Jensen, J. Wisniewska-Kruk, M. Corada, Frank Chenfei Ning, Julianna Kele, E. Dejana, D. Nyqvist","doi":"10.1161/ATVBAHA.119.312749","DOIUrl":"https://doi.org/10.1161/ATVBAHA.119.312749","url":null,"abstract":"OBJECTIVE\u0000Activation of endothelial β-catenin signaling by neural cell-derived Norrin or Wnt ligands is vital for the vascularization of the retina and brain. Mutations in members of the Norrin/β-catenin pathway contribute to inherited blinding disorders because of defective vascular development and dysfunctional blood-retina barrier. Despite a vital role for endothelial β-catenin signaling in central nervous system health and disease, its contribution to central nervous system angiogenesis and its interactions with downstream signaling cascades remains incompletely understood. Approach and Results: Here, using genetically modified mouse models, we show that impaired endothelial β-catenin signaling caused hypovascularization of the postnatal retina and brain because of deficient endothelial cell proliferation and sprouting. Mosaic genetic analysis demonstrated that endothelial β-catenin promotes but is not required for tip cell formation. In addition, pharmacological treatment revealed that angiogenesis under conditions of inhibited Notch signaling depends upon endothelial β-catenin. Importantly, impaired endothelial β-catenin signaling abrogated the expression of the VEGFR (vascular endothelial growth factor receptor)-2 and VEGFR3 in brain microvessels but not in the lung endothelium.\u0000\u0000\u0000CONCLUSIONS\u0000Our study identifies molecular crosstalk between the Wnt/β-catenin and the Notch and VEGF-A signaling pathways and strongly suggest that endothelial β-catenin signaling supports central nervous system angiogenesis by promoting endothelial cell sprouting, tip cell formation, and VEGF-A/VEGFR2 signaling.","PeriodicalId":8404,"journal":{"name":"Arteriosclerosis, Thrombosis, & Vascular Biology","volume":"8 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83812261","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Arterial Stiffness Modulates the Association of Resting Heart Rate With Rapid Renal Function Decline in Individuals With Type 2 Diabetes Mellitus.","authors":"Jian-jun Liu, Sylvia Liu, R. L. Gurung, K. Ang, Wern Ee Tang, C. Sum, S. Tavintharan, S. Hadjadj, S. Lim","doi":"10.1161/ATVBAHA.119.313163","DOIUrl":"https://doi.org/10.1161/ATVBAHA.119.313163","url":null,"abstract":"OBJECTIVE\u0000Resting heart rate (RHR) has been associated with cardiovascular risk, but data on renal outcomes are still scarce. We aimed to study the association of RHR with rapid renal function decline (RRFD) and to explore whether the association of RHR with RRFD is modulated by arterial stiffness in individuals with type 2 diabetes mellitus. Approach and Results: One thousand one hundred forty-two Asian people with type 2 diabetes mellitus were followed for 3.9±0.9 years in a regional hospital and a primary care facility. RRFD was defined as eGFR decline of 5 mL/min per 1.73 m2 or greater per year. Arterial stiffness was assessed by carotid-femoral pulse wave velocity. One hundred sixty-eight participants (15%) were classified as having RRFD. Participants with elevated RHR were younger, had higher levels of HbA1c, albuminuria, C-reactive protein, and pulse wave velocity. Compared with the lowest quartile, participants in quartile 4 had a higher risk for RRFD after adjustment for known risk factors (adjusted odds ratio 1.91 [1.11-3.28]). RHR improved discrimination and net reclassification for prediction of RRFD above traditional risk factors. Remarkably, arterial stiffness modulated the association of RHR with RRFD (P for interaction =0.03). RHR was significantly associated with risk of RRFD only in those with increased arterial stiffness (pulse wave velocity above age-reference value 7.7 m/s).\u0000\u0000\u0000CONCLUSIONS\u0000RHR independently predicts RRFD, and the association is modulated by arterial stiffness. An elevated heart rate may be one factor in the spectrum of cardiovascular risk factors associated with renal functional impairment, especially in those with type 2 diabetes mellitus and an increased arterial stiffness.","PeriodicalId":8404,"journal":{"name":"Arteriosclerosis, Thrombosis, & Vascular Biology","volume":"15 11","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91469199","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Endothelial Targets in Stroke: Translating Animal Models to Human.","authors":"A. Andjelkovic, J. Xiang, S. Stamatovic, Y. Hua, G. Xi, Michael M. Wang, R. Keep","doi":"10.1161/ATVBAHA.119.312816","DOIUrl":"https://doi.org/10.1161/ATVBAHA.119.312816","url":null,"abstract":"Cerebral ischemia (stroke) induces injury to the cerebral endothelium that may contribute to parenchymal injury and worsen outcome. This review focuses on current preclinical studies examining how to prevent ischemia-induced endothelial dysfunction. It particularly focuses on targets at the endothelium itself. Those include endothelial tight junctions, transcytosis, endothelial cell death, and adhesion molecule expression. It also examines how such studies are being translated to the clinic, especially as adjunct therapies for preventing intracerebral hemorrhage during reperfusion of the ischemic brain. Identification of endothelial targets may prove valuable in a search for combination therapies that would specifically protect different cell types in ischemia.","PeriodicalId":8404,"journal":{"name":"Arteriosclerosis, Thrombosis, & Vascular Biology","volume":"4 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81517633","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"ALDH2 (Aldehyde Dehydrogenase 2) Protects Against Hypoxia-Induced Pulmonary Hypertension.","authors":"Yu Zhao, Bailu Wang, Jian Zhang, Dayu He, Qun Zhang, C. Pan, Qiu-huan Yuan, Yinan Shi, Haiyang Tang, F. Xu, Shujian Wei, Yuguo Chen","doi":"10.1161/ATVBAHA.119.312946","DOIUrl":"https://doi.org/10.1161/ATVBAHA.119.312946","url":null,"abstract":"OBJECTIVE\u0000Hypoxia-induced pulmonary hypertension (HPH) increases lipid peroxidation with generation of toxic aldehydes that are metabolized by detoxifying enzymes, including ALDH2 (aldehyde dehydrogenase 2). However, the role of lipid peroxidation and ALDH2 in HPH pathogenesis remain undefined. Approach and Results: To determine the role of lipid peroxidation and ALDH2 in HPH, C57BL/6 mice, ALDH2 transgenic mice, and ALDH2 knockout (ALDH2-/-) mice were exposed to chronic hypoxia, and recombinant tissue-specific ALDH2 overexpression adeno-associated viruses were introduced into pulmonary arteries via tail vein injection for ALDH2 overexpression. Human pulmonary artery smooth muscle cells were used to elucidate underlying mechanisms in vitro. Chronic hypoxia promoted lipid peroxidation due to the excessive production of reactive oxygen species and increased expression of lipoxygenases in lung tissues. 4-hydroxynonenal but not malondialdehyde level was increased in hypoxic lung tissues which might reflect differences in detoxifying enzymes. ALDH2 overexpression attenuated the development of HPH, whereas ALDH2 knockout aggravated it. Specific overexpression of ALDH2 using AAV1-ICAM (intercellular adhesion molecule) 2p-ALDH2 and AAV2-SM22αp-ALDH2 viral vectors in pulmonary artery smooth muscle cells, but not endothelial cells, prevented the development of HPH. Hypoxia or 4-hydroxynonenal increased stabilization of HIF (hypoxia-inducible factor)-1α, phosphorylation of Drp1 (dynamin-related protein 1) at serine 616, mitochondrial fission, and pulmonary artery smooth muscle cells proliferation, whereas ALDH2 activation suppressed the latter 3.\u0000\u0000\u0000CONCLUSIONS\u0000Increased 4-hydroxynonenal level plays a critical role in the development of HPH. ALDH2 attenuates the development of HPH by regulating mitochondrial fission and smooth muscle cell proliferation suggesting ALDH2 as a potential new therapeutic target for pulmonary hypertension.","PeriodicalId":8404,"journal":{"name":"Arteriosclerosis, Thrombosis, & Vascular Biology","volume":"33 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80135681","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ser-Phosphorylation of PCSK9 (Proprotein Convertase Subtilisin-Kexin 9) by Fam20C (Family With Sequence Similarity 20, Member C) Kinase Enhances Its Ability to Degrade the LDLR (Low-Density Lipoprotein Receptor).","authors":"Ali Ben Djoudi Ouadda, M. Gauthier, Delia Susan-Resiga, E. Girard, R. Essalmani, M. Black, J. Marcinkiewicz, D. Forget, J. Hamelin, A. Evagelidis, Kévin Ly, R. Day, L. Galarneau, F. Corbin, B. Coulombe, A. Çaku, V. Tagliabracci, N. Seidah","doi":"10.1161/ATVBAHA.119.313247","DOIUrl":"https://doi.org/10.1161/ATVBAHA.119.313247","url":null,"abstract":"OBJECTIVE PCSK9 (proprotein convertase subtilisin-kexin 9) enhances the degradation of the LDLR (low-density lipoprotein receptor) in endosomes/lysosomes. This study aimed to determine the sites of PCSK9 phosphorylation at Ser-residues and the consequences of such posttranslational modification on the secretion and activity of PCSK9 on the LDLR. Approach and Results: Fam20C (family with sequence similarity 20, member C) phosphorylates serines in secretory proteins containing the motif S-X-E/phospho-Ser, including the cholesterol-regulating PCSK9. In situ hybridization of Fam20C mRNA during development and in adult mice revealed a wide tissue distribution, including liver, but not small intestine. Here, we show that Fam20C phosphorylates PCSK9 at Serines 47, 666, 668, and 688. In hepatocytes, phosphorylation enhances PCSK9 secretion and maximizes its induced degradation of the LDLR via the extracellular and intracellular pathways. Replacing any of the 4 Ser by the phosphomimetic Glu or Asp enhanced PCSK9 activity only when the other sites are phosphorylated, whereas Ala substitutions reduced it, as evidenced by Western blotting, Elisa, and LDLR-immunolabeling. This newly uncovered PCSK9/LDLR regulation mechanism refines our understanding of the implication of global PCSK9 phosphorylation in the modulation of LDL-cholesterol and rationalizes the consequence of natural mutations, for example, S668R and E670G. Finally, the relationship of Ser-phosphorylation to the implication of PCSK9 in regulating LDL-cholesterol in the neurological Fragile X-syndrome disorder was investigated. CONCLUSIONS Ser-phosphorylation of PCSK9 maximizes both its secretion and activity on the LDLR. Mass spectrometric approaches to measure such modifications were developed and applied to quantify the levels of bioactive PCSK9 in human plasma under normal and pathological conditions.","PeriodicalId":8404,"journal":{"name":"Arteriosclerosis, Thrombosis, & Vascular Biology","volume":"51 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86880497","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}