Combined action of albumin and heparin regulates lipoprotein lipase oligomerization, stability, and ligand interactions

Lipoprotein lipase (LPL), a crucial enzyme in the intravascular hydrolysis of triglyceride-rich lipoproteins, is a potential drug target for the treatment of hypertriglyceridemia. The activity and stability of LPL are influenced by a complex ligand network. Previous studies performed in dilute solutions suggest that LPL can appear in various oligomeric states. However, it was not known how the physiological environment, that is blood plasma, affects the action of LPL. In the current study, we demonstrate that albumin, the major protein component in blood plasma, has a significant impact on LPL stability, oligomerization, and ligand interactions. The effects induced by albumin could not solely be reproduced by the macromolecular crowding effect. Stabilization, isothermal titration calorimetry, and surface plasmon resonance studies revealed that albumin binds to LPL with affinity sufficient to form a complex in both the interstitial space and the capillaries. Negative stain transmission electron microscopy and raster image correlation spectroscopy showed that albumin, like heparin, induced reversible oligomerization of LPL. However, the albumin induced oligomers were structurally different from heparin-induced filament-like LPL oligomers. An intriguing observation was that no oligomers of either type were formed in the simultaneous presence of albumin and heparin. Our data also suggested that the oligomer formation protected LPL from the inactivation by its physiological regulator angiopoietin-like protein 4. The concentration of LPL and its environment could influence whether LPL follows irreversible inactivation and aggregation or reversible LPL oligomer formation, which might affect interactions with various ligands and drugs. In conclusion, the interplay between albumin and heparin could provide a mechanism for ensuring the dissociation of heparan sulfate-bound LPL oligomers into active LPL upon secretion into the interstitial space.

[1]  M. Jankowski,et al.  Hypertriglyceridemia, a causal risk factor for atherosclerosis, and its laboratory assessment , 2022, Clinical chemistry and laboratory medicine.

[2]  J. Borén,et al.  Metabolism of triglyceride-rich lipoproteins in health and dyslipidaemia , 2022, Nature Reviews Cardiology.

[3]  Y. Qian,et al.  ApoA5 lowers triglyceride levels via suppression of ANGPTL3/8-mediated LPL inhibition , 2021, Journal of lipid research.

[4]  S. Neher,et al.  Comparison of angiopoietin-like protein 3 and 4 reveals structural and mechanistic similarities , 2021, The Journal of biological chemistry.

[5]  A. Remaley,et al.  Hypertriglyceridemia: new approaches in management and treatment , 2020, Current opinion in lipidology.

[6]  J. Tong,et al.  Effects of macromolecular crowding on the folding and aggregation of glycosylated MUC5AC. , 2020, Biochemical and biophysical research communications.

[7]  M. Borgnia,et al.  The structure of helical lipoprotein lipase reveals an unexpected twist in lipase storage , 2020, Proceedings of the National Academy of Sciences.

[8]  S. Young,et al.  ANGPTL4 inactivates lipoprotein lipase by catalyzing the irreversible unfolding of LPL’s hydrolase domain , 2020, Journal of Lipid Research.

[9]  S. Young,et al.  Unfolding of monomeric lipoprotein lipase by ANGPTL4: Insight into the regulation of plasma triglyceride metabolism , 2020, Proceedings of the National Academy of Sciences.

[10]  C. Burd,et al.  Syndecan-1 Mediates Sorting of Soluble Lipoprotein Lipase with Sphingomyelin-Rich Membrane in the Golgi Apparatus. , 2019, Developmental cell.

[11]  A. Remaley,et al.  Apolipoprotein C-II mimetic peptide is an efficient activator of lipoprotein lipase in human plasma as studied by a calorimetric approach. , 2019, Biochemical and biophysical research communications.

[12]  S. Kersten.  New insights into angiopoietin-like proteins in lipid metabolism and cardiovascular disease risk , 2019, Current opinion in lipidology.

[13]  Thomas M. Smith,et al.  Structure of lipoprotein lipase in complex with GPIHBP1 , 2019, Proceedings of the National Academy of Sciences.

[14]  S. Young,et al.  Lipoprotein lipase is active as a monomer , 2019, Proceedings of the National Academy of Sciences.

[15]  S. Neher,et al.  Mapping the sites of the lipoprotein lipase (LPL)–angiopoietin-like protein 4 (ANGPTL4) interaction provides mechanistic insight into LPL inhibition , 2018, The Journal of Biological Chemistry.

[16]  S. Young,et al.  Structure of the lipoprotein lipase–GPIHBP1 complex that mediates plasma triglyceride hydrolysis , 2018, Proceedings of the National Academy of Sciences.

[17]  M. Banach,et al.  Novel Therapeutic Targets for Managing Dyslipidemia. , 2018, Trends in pharmacological sciences.

[18]  S. Kersten,et al.  Angiopoietin-like 4 promotes the intracellular cleavage of lipoprotein lipase by PCSK3/furin in adipocytes , 2018, The Journal of Biological Chemistry.

[19]  S. Shetty,et al.  ANGPTL8 promotes the ability of ANGPTL3 to bind and inhibit lipoprotein lipase , 2017, Molecular metabolism.

[20]  R. Winter,et al.  Influence of isoform-specific Ras lipidation motifs on protein partitioning and dynamics in model membrane systems of various complexity , 2017, Biological chemistry.

[21]  G. Olivecrona,et al.  Lipoprotein lipase activity and interactions studied in human plasma by isothermal titration calorimetry , 2016, Journal of Lipid Research.

[22]  S. Young,et al.  The angiopoietin-like protein ANGPTL4 catalyzes unfolding of the hydrolase domain in lipoprotein lipase and the endothelial membrane protein GPIHBP1 counteracts this unfolding , 2016, eLife.

[23]  B. Nordestgaard.  Triglyceride-Rich Lipoproteins and Atherosclerotic Cardiovascular Disease: New Insights From Epidemiology, Genetics, and Biology. , 2016, Circulation research.

[24]  G. Olivecrona,et al.  Evidence for Two Distinct Binding Sites for Lipoprotein Lipase on Glycosylphosphatidylinositol-anchored High Density Lipoprotein-binding Protein 1 (GPIHBP1)* , 2015, The Journal of Biological Chemistry.

[25]  V. Uversky,et al.  What Macromolecular Crowding Can Do to a Protein , 2014, International journal of molecular sciences.

[26]  S. Young,et al.  The GPIHBP1-LPL complex is responsible for the margination of triglyceride-rich lipoproteins in capillaries. , 2014, Cell metabolism.

[27]  S. Neher,et al.  Angiopoietin-like Protein 4 Inhibition of Lipoprotein Lipase , 2013, The Journal of Biological Chemistry.

[28]  S. Young,et al.  Assessing mechanisms of GPIHBP1 and lipoprotein lipase movement across endothelial cells[S] , 2012, Journal of Lipid Research.

[29]  G. Pielak,et al.  Unexpected effects of macromolecular crowding on protein stability. , 2012, Biochemistry.

[30]  T. Olivecrona,et al.  Inactivation of lipoprotein lipase occurs on the surface of THP-1 macrophages where oligomers of angiopoietin-like protein 4 are formed. , 2012, Biochemical and biophysical research communications.

[31]  G. Olivecrona,et al.  Fatty Acids Bind Tightly to the N-terminal Domain of Angiopoietin-like Protein 4 and Modulate Its Interaction with Lipoprotein Lipase* , 2012, The Journal of Biological Chemistry.

[32]  J. Graaf,et al.  Serum triglycerides and risk of cardiovascular disease. , 2012, Biochimica et biophysica acta.

[33]  Ardo Illaste,et al.  Analysis of molecular movement reveals latticelike obstructions to diffusion in heart muscle cells. , 2012, Biophysical journal.

[34]  S. Young,et al.  GPIHBP1 is responsible for the entry of lipoprotein lipase into capillaries. , 2010, Cell metabolism.

[35]  J. Danesh,et al.  Triglyceride-mediated pathways and coronary disease: collaborative analysis of 101 studies , 2010, The Lancet.

[36]  Y. Hu,et al.  GPIHBP1 stabilizes lipoprotein lipase and prevents its inhibition by angiopoietin-like 3 and angiopoietin-like 4 , 2009, Journal of Lipid Research.

[37]  R. Eckel,et al.  Lipoprotein lipase : from gene to obesity , 2009 .

[38]  Marko Vendelin,et al.  Anisotropic diffusion of fluorescently labeled ATP in rat cardiomyocytes determined by raster image correlation spectroscopy , 2008, American journal of physiology. Cell physiology.

[39]  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.

[40]  F. Sacks,et al.  Lipoprotein Lipase Bound to Apolipoprotein B Lipoproteins Accelerates Clearance of Postprandial Lipoproteins in Humans , 2006, Arteriosclerosis, thrombosis, and vascular biology.

[41]  G. Olivecrona,et al.  Calcium Triggers Folding of Lipoprotein Lipase into Active Dimers* , 2005, Journal of Biological Chemistry.

[42]  G. Olivecrona,et al.  Rapid Subunit Exchange in Dimeric Lipoprotein Lipase and Properties of the Inactive Monomer* , 2004, Journal of Biological Chemistry.

[43]  Tetsuya Yomo,et al.  Protein folding by the effects of macromolecular crowding , 2004, Protein science : a publication of the Protein Society.

[44]  R. Ellis.  Macromolecular crowding : obvious but underappreciated , 2022 .

[45]  M. Ellmerer,et al.  Measurement of interstitial albumin in human skeletal muscle and adipose tissue by open-flow microperfusion. , 2000, American journal of physiology. Endocrinology and metabolism.

[46]  L. Havekes,et al.  Role of ApoCs in lipoprotein metabolism: functional differences between ApoC1, ApoC2, and ApoC3. , 1999, Arteriosclerosis, thrombosis, and vascular biology.

[47]  G. Olivecrona,et al.  Interaction of lipoprotein lipase with heparin fragments and with heparan sulfate: stoichiometry, stabilization, and kinetics. , 1996, Biochemistry.

[48]  T. Olivecrona,et al.  Forms of lipoprotein lipase in rat tissues: in adipose tissue the proportion of inactive lipase increases on fasting. , 1996, The Biochemical journal.

[49]  A. Hamsten,et al.  Lipoprotein lipase in plasma after an oral fat load: relation to free fatty acids. , 1992, Journal of lipid research.

[50]  T. Olivecrona,et al.  Phospholipase activity of milk lipoprotein lipase. , 1991, Methods in enzymology.

[51]  Hurst Jw,et al.  Serum Albumin and Globulin -- Clinical Methods: The History, Physical, and Laboratory Examinations , 1990 .

[52]  I. Goldberg,et al.  Release of endothelial cell lipoprotein lipase by plasma lipoproteins and free fatty acids. , 1989, The Journal of biological chemistry.

[53]  G. Bengtsson-Olivecrona,et al.  Hydrolysis of bovine and caprine milk fat globules by lipoprotein lipase. Effects of heparin and of skim milk on lipase distribution and on lipolysis. , 1987, Journal of dairy science.

[54]  J. C. Osborne,et al.  Molecular size of bovine lipoprotein lipase as determined by radiation inactivation. , 1985, The Journal of biological chemistry.

[55]  M. Brown,et al.  Receptor-mediated endocytosis of low-density lipoprotein in cultured cells. , 1983, Methods in enzymology.

[56]  T. Olivecrona,et al.  Lipoprotein lipase. Mechanism of product inhibition. , 1980, European journal of biochemistry.

[57]  T. Olivecrona,et al.  Kinetics of milk lipoprotein lipase. Studies with tributyrin. , 1978, European journal of biochemistry.

[58]  J. Larosa,et al.  A specific apoprotein activator for lipoprotein lipase. , 1970, Biochemical and biophysical research communications.