Rare loss-of-function mutations in ANGPTL family members contribute to plasma triglyceride levels in humans.

The relative activity of lipoprotein lipase (LPL) in different tissues controls the partitioning of lipoprotein-derived fatty acids between sites of fat storage (adipose tissue) and oxidation (heart and skeletal muscle). Here we used a reverse genetic strategy to test the hypothesis that 4 angiopoietin-like proteins (ANGPTL3, -4, -5, and -6) play key roles in triglyceride (TG) metabolism in humans. We re-sequenced the coding regions of the genes encoding these proteins and identified multiple rare nonsynonymous (NS) sequence variations that were associated with low plasma TG levels but not with other metabolic phenotypes. Functional studies revealed that all mutant alleles of ANGPTL3 and ANGPTL4 that were associated with low plasma TG levels interfered either with the synthesis or secretion of the protein or with the ability of the ANGPTL protein to inhibit LPL. A total of 1% of the Dallas Heart Study population and 4% of those participants with a plasma TG in the lowest quartile had a rare loss-of-function mutation in ANGPTL3, ANGPTL4, or ANGPTL5. Thus, ANGPTL3, ANGPTL4, and ANGPTL5, but not ANGPTL6, play nonredundant roles in TG metabolism, and multiple alleles at these loci cumulatively contribute to variability in plasma TG levels in humans.

[1]  S. Wattler,et al.  Identification of a mammalian angiopoietin-related protein expressed specifically in liver. , 1999, Genomics.

[2]  Kenichi Yoshida,et al.  Angiopoietin-like protein 4 is a potent hyperlipidemia-inducing factor in mice and inhibitor of lipoprotein lipase Published, JLR Papers in Press, September 16, 2002. DOI 10.1194/jlr.C200010-JLR200 , 2002, Journal of Lipid Research.

[3]  Jonathan C. Cohen,et al.  A spectrum of PCSK9 alleles contributes to plasma levels of low-density lipoprotein cholesterol. , 2006, American journal of human genetics.

[4]  Kenichi Yoshida,et al.  Protein Region Important for Regulation of Lipid Metabolism in Angiopoietin-like 3 (ANGPTL3) , 2003, Journal of Biological Chemistry.

[5]  Alexander Pertsemlidis,et al.  Low LDL cholesterol in individuals of African descent resulting from frequent nonsense mutations in PCSK9 , 2005, Nature Genetics.

[6]  H. Lodish,et al.  Angiopoietin-like 5 and IGFBP2 stimulate ex vivo expansion of human cord blood hematopoietic stem cells as assayed by NOD/SCID transplantation. , 2008, Blood.

[7]  Shamil R Sunyaev,et al.  Most rare missense alleles are deleterious in humans: implications for complex disease and association studies. , 2007, American journal of human genetics.

[8]  Dolores Corella,et al.  Six new loci associated with blood low-density lipoprotein cholesterol, high-density lipoprotein cholesterol or triglycerides in humans , 2008, Nature Genetics.

[9]  T. Olivecrona,et al.  Angiopoietin-like protein 4 converts lipoprotein lipase to inactive monomers and modulates lipase activity in adipose tissue , 2006, Proceedings of the National Academy of Sciences.

[10]  Steven Henikoff,et al.  SIFT: predicting amino acid changes that affect protein function , 2003, Nucleic Acids Res..

[11]  P. Nilsson-ehle,et al.  A stable, radioactive substrate emulsion for assay of lipoprotein lipase. , 1976, Journal of lipid research.

[12]  Kenichi Yoshida,et al.  ANGPTL3 Decreases Very Low Density Lipoprotein Triglyceride Clearance by Inhibition of Lipoprotein Lipase* , 2002, The Journal of Biological Chemistry.

[13]  Guoqing Yang,et al.  Oligomerization state-dependent hyperlipidemic effect of angiopoietin-like protein 4 Published, JLR Papers in Press, August 1, 2004. DOI 10.1194/jlr.M400138-JLR200 , 2004, Journal of Lipid Research.

[14]  Kang Ying,et al.  Identification of a novel human angiopoietin-like gene expressed mainly in heart , 2003, Journal of Human Genetics.

[15]  L. Havekes,et al.  Severe hypertriglyceridemia in human APOC1 transgenic mice is caused by apoC-I-induced inhibition of LPL Published, JLR Papers in Press, December 1, 2004. DOI 10.1194/jlr.M400301-JLR200 , 2005, Journal of Lipid Research.

[16]  J. Cha,et al.  Differential regulation and properties of angiopoietin-like proteins 3 and 4 Published, JLR Papers in Press, May 1, 2005. DOI 10.1194/jlr.M500005-JLR200 , 2005, Journal of Lipid Research.

[17]  Cai Li.  Genetics and regulation of angiopoietin-like proteins 3 and 4 , 2006, Current opinion in lipidology.

[18]  Jonathan C. Cohen,et al.  Multiple Rare Alleles Contribute to Low Plasma Levels of HDL Cholesterol , 2004, Science.

[19]  S. Grundy,et al.  Magnetic resonance spectroscopy to measure hepatic triglyceride content: prevalence of hepatic steatosis in the general population. , 2005, American journal of physiology. Endocrinology and metabolism.

[20]  C. Fraser,et al.  Transgenic angiopoietin-like (angptl)4 overexpression and targeted disruption of angptl4 and angptl3: regulation of triglyceride metabolism. , 2005, Endocrinology.

[21]  R. Eckel,et al.  Lipoprotein lipase : genetics , lipid uptake , and regulation , 2002 .

[22]  Warren C. Lathe,et al.  Prediction of deleterious human alleles. , 2001, Human molecular genetics.

[23]  T. Fujiwara,et al.  Angptl3 regulates lipid metabolism in mice , 2002, Nature Genetics.

[24]  ShizuyaYamashita,et al.  Angiopoietin-Like Protein3 Regulates Plasma HDL Cholesterol Through Suppression of Endothelial Lipase , 2007 .

[25]  T. Suda,et al.  Angiopoietin-related growth factor antagonizes obesity and insulin resistance , 2005, Nature Medicine.

[26]  Guoqing Yang,et al.  Oligomerization and Regulated Proteolytic Processing of Angiopoietin-like Protein 4* , 2004, Journal of Biological Chemistry.

[27]  Eric Boerwinkle,et al.  Population-based resequencing of ANGPTL4 uncovers variations that reduce triglycerides and increase HDL , 2007, Nature Genetics.

[28]  R. Collins,et al.  Newly identified loci that influence lipid concentrations and risk of coronary artery disease , 2008, Nature Genetics.

[29]  J. Xu,et al.  Cloning, expression and characterization of a novel human REPS1 gene. , 2001, Biochimica et biophysica acta.

[30]  Ronald M Peshock,et al.  The Dallas Heart Study: a population-based probability sample for the multidisciplinary study of ethnic differences in cardiovascular health. , 2004, The American journal of cardiology.

[31]  D. Rader,et al.  Characterization of the lipolytic activity of endothelial lipase. , 2002, Journal of lipid research.

[32]  Jian Xu,et al.  Identification of a novel human doublecortin-domain-containing gene (DCDC1) expressed mainly in testis , 2003, Journal of Human Genetics.

[33]  B. Spiegelman,et al.  Peroxisome Proliferator-Activated Receptor γ Target Gene Encoding a Novel Angiopoietin-Related Protein Associated with Adipose Differentiation , 2000, Molecular and Cellular Biology.

[34]  D. Rader,et al.  Hepatic proprotein convertases modulate HDL metabolism. , 2007, Cell metabolism.

[35]  Jonathan C. Cohen,et al.  Functional characterization of genetic variants in NPC1L1 supports the sequencing extremes strategy to identify complex trait genes , 2008, Human molecular genetics.

[36]  P. Chambon,et al.  Characterization of the Fasting-induced Adipose Factor FIAF, a Novel Peroxisome Proliferator-activated Receptor Target Gene* , 2000, The Journal of Biological Chemistry.

[37]  Jonathan C. Cohen,et al.  Multiple rare variants in NPC1L1 associated with reduced sterol absorption and plasma low-density lipoprotein levels. , 2006, Proceedings of the National Academy of Sciences of the United States of America.