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Huang F, Wang K, Shen J. Lipoprotein-associated phospholipase A2: The story continues. Med Res Rev 2019; 40:79-134. [PMID: 31140638 PMCID: PMC6973114 DOI: 10.1002/med.21597] [Citation(s) in RCA: 95] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Revised: 04/20/2019] [Accepted: 04/30/2019] [Indexed: 12/15/2022]
Abstract
Inflammation is thought to play an important role in the pathogenesis of vascular diseases. Lipoprotein-associated phospholipase A2 (Lp-PLA2) mediates vascular inflammation through the regulation of lipid metabolism in blood, thus, it has been extensively investigated to identify its role in vascular inflammation-related diseases, mainly atherosclerosis. Although darapladib, the most advanced Lp-PLA2 inhibitor, failed to meet the primary endpoints of two large phase III trials in atherosclerosis patients cotreated with standard medical care, the research on Lp-PLA2 has not been terminated. Novel pathogenic, epidemiologic, genetic, and crystallographic studies regarding Lp-PLA2 have been reported recently, while novel inhibitors were identified through a fragment-based lead discovery strategy. More strikingly, recent clinical and preclinical studies revealed that Lp-PLA2 inhibition showed promising therapeutic effects in diabetic macular edema and Alzheimer's disease. In this review, we not only summarized the knowledge of Lp-PLA2 established in the past decades but also emphasized new findings in recent years. We hope this review could be valuable for helping researchers acquire a much deeper insight into the nature of Lp-PLA2, identify more potent and selective Lp-PLA2 inhibitors, and discover the potential indications of Lp-PLA2 inhibitors.
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Affiliation(s)
- Fubao Huang
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica (SIMM), Chinese Academy of Sciences, Shanghai, China.,School of Pharmacy, University of Chinese Academy of Sciences, Beijing, China
| | - Kai Wang
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica (SIMM), Chinese Academy of Sciences, Shanghai, China
| | - Jianhua Shen
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica (SIMM), Chinese Academy of Sciences, Shanghai, China
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Zhuo S, Wolfert RL, Yuan C. Biochemical differences in the mass and activity tests of lipoprotein-associated phospholipase A 2 explain the discordance in results between the two assay methods. Clin Biochem 2017; 50:1209-1215. [DOI: 10.1016/j.clinbiochem.2017.08.019] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Revised: 08/07/2017] [Accepted: 08/15/2017] [Indexed: 01/20/2023]
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Abstract
The structure of plasma PAF-AH was solved to a resolution of 1.5Å using X-ray crystallography. The enzyme has a classic α/β serine hydrolase fold containing a catalytic triad of Ser273, Asp296, and His351. A hydrophobic patch of the enzyme involving two α-helices (114-126 and 362-369) and neighboring residues have been shown to be essential for lipoprotein particle binding by mutagenesis and mass spectrometry hydrogen/deuterium exchange experiments. An interface-bound model of the enzyme positions the active site above the hydrophobic-hydrophilic interface and is consistent with the known substrate specificity of the enzyme. Several ligand-bound structures of plasma PAF-AH have been solved with organophosphorus compounds and modeled with competitive inhibitors of high affinity and selectivity. This chapter presents an overview of the structure of plasma PAF-AH, molecular details of its functional role, and the interaction of the enzyme with lipoprotein particles.
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Plasma PAF-AH (PLA2G7): Biochemical Properties, Association with LDLs and HDLs, and Regulation of Expression. Enzymes 2015; 38:71-93. [PMID: 26612648 DOI: 10.1016/bs.enz.2015.09.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
This chapter is focused on the plasma form of PAF-acetylhydrolase (PAF-AH), a lipoprotein-bound, calcium-independent phospholipase A2 activity also referred to as lipoprotein-associated phospholipase A2 and PLA2G7. PAF-AH catalyzes the removal of the acyl group at the sn-2 position of PAF and truncated phospholipids generated in settings of inflammation and oxidant stress. Here, I discuss current knowledge related to the structural features of this enzyme, including the molecular basis for association with lipoproteins and susceptibility to oxidative inactivation. The circulating form of PAF-AH is constitutively active and its expression is upregulated by mediators of inflammation at the transcriptional level. Several new mechanisms of regulation have been identified in recent years, including effects mediated by PPARs, VEGFR, and the state of cellular differentiation. Moreover, I discuss recent studies describing significant variations in the structure and regulation of PAF-AH from diverse species, which is likely to have important implications for the function of this enzyme in vivo.
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Kirby SD, Norris J, Sweeney R, Bahnson BJ, Cerasoli DM. A rationally designed mutant of plasma platelet-activating factor acetylhydrolase hydrolyzes the organophosphorus nerve agent soman. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2015; 1854:1809-1815. [PMID: 26343853 DOI: 10.1016/j.bbapap.2015.09.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2015] [Revised: 07/21/2015] [Accepted: 09/01/2015] [Indexed: 01/20/2023]
Abstract
Organophosphorus compounds (OPs) such as sarin and soman are some of the most toxic chemicals synthesized by man. They exert toxic effects by inactivating acetylcholinesterase (AChE) and bind secondary target protein. Organophosphorus compounds are hemi-substrates for enzymes of the serine hydrolase superfamily. Enzymes can be engineered by amino acid substitution into OP-hydrolyzing variants (bioscavengers) and used as therapeutics. Some enzymes associated with lipoproteins, such as human plasma platelet-activating factor acetylhydrolase (pPAF-AH), are also inhibited by OPs; these proteins have largely been ignored for engineering purposes because of complex interfacial kinetics and a lack of structural data. We have expressed active human pPAF-AH in bacteria and previously solved the crystal structure of this enzyme with OP adducts. Using these structures as a guide, we created histidine mutations near the active site of pPAF-AH (F322H, W298H, L153H) in an attempt to generate novel OP-hydrolase activity. Wild-type pPAF-AH, L153H, and F322H have essentially no hydrolytic activity against the nerve agents tested. In contrast, the W298H mutant displayed novel somanase activity with a kcat of 5min(-1) and a KM of 590μM at pH7.5. There was no selective preference for hydrolysis of any of the four soman stereoisomers.
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Affiliation(s)
- Stephen D Kirby
- U.S. Army Medical Research Institute of Chemical Defense, APG, MD 21010, United States; Department of Chemistry & Biochemistry, University of Delaware, Newark, DE 19716, United States.
| | - Joseph Norris
- U.S. Army Medical Research Institute of Chemical Defense, APG, MD 21010, United States
| | - Richard Sweeney
- U.S. Army Medical Research Institute of Chemical Defense, APG, MD 21010, United States
| | - Brian J Bahnson
- Department of Chemistry & Biochemistry, University of Delaware, Newark, DE 19716, United States
| | - Douglas M Cerasoli
- U.S. Army Medical Research Institute of Chemical Defense, APG, MD 21010, United States
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Nankar SA, Bajaj P, Sravanthi R, Pande AH. Differential interaction of peptides derived from C-terminal domain of human apolipoprotein E with platelet activating factor analogs. Biochimie 2013; 95:1196-207. [DOI: 10.1016/j.biochi.2013.01.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2012] [Accepted: 01/16/2013] [Indexed: 11/25/2022]
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The Chemical Nature of the Polar Functional Group of Oxidized Acyl Chain Uniquely Modifies the Physicochemical Properties of Oxidized Phospholipid-Containing Lipid Particles. J Membr Biol 2013; 246:443-52. [DOI: 10.1007/s00232-013-9556-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Accepted: 04/23/2013] [Indexed: 02/02/2023]
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Nankar SA, Pande AH. Physicochemical properties of bacterial pro-inflammatory lipids influence their interaction with apolipoprotein-derived peptides. Biochim Biophys Acta Mol Cell Biol Lipids 2013; 1831:853-62. [DOI: 10.1016/j.bbalip.2013.01.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2012] [Revised: 12/21/2012] [Accepted: 01/07/2013] [Indexed: 11/26/2022]
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Kar S, Patel MA, Tripathy RK, Bajaj P, Suvarnakar UV, Pande AH. Oxidized phospholipid content destabilizes the structure of reconstituted high density lipoprotein particles and changes their function. Biochim Biophys Acta Mol Cell Biol Lipids 2012; 1821:1200-10. [PMID: 22634518 DOI: 10.1016/j.bbalip.2012.05.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2012] [Revised: 05/02/2012] [Accepted: 05/11/2012] [Indexed: 11/16/2022]
Abstract
High density lipoprotein (HDL) particles are made up of lipid and protein constituents and apolipoprotein A-I (apoA-I) is a principal protein component that facilitates various biological activities of HDL particles. Increase in Ox-PL content of HDL particles makes them 'dysfunctional' and such modified HDL particles not only lose their athero-protective properties but also acquire pro-atherogenic and pro-inflammatory functions. The details of Ox-PL-induced alteration in the molecular properties of HDL particles are not clear. Paraoxonase 1 (PON1) is an HDL-associated enzyme that possesses anti-inflammatory and anti-atherogenic properties; and many of the athero-protective functions of HDL are attributed to the associated PON1. In this study we have characterized the physicochemical properties of reconstituted HDL (rHDL) particles containing varying amounts of Ox-PL and have compared their PON1 stimulation capacity. Our results show that increased Ox-PL content (a) modifies the physicochemical properties of the lipid domain of the rHDL particles, (b) decreases the stability and alters the conformation as well as orientation of apoA-I molecules on the rHDL particles, and (c) decreases the PON1 stimulation capacity of the rHDL particles. Our data indicate that the presence of Ox-PLs destabilizes the structure of the HDL particles and modifies their function.
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Affiliation(s)
- Subhabrata Kar
- Department of Biotechnology, National Institute of Pharmaceutical Education and Research, Punjab, India
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Dennis EA, Cao J, Hsu YH, Magrioti V, Kokotos G. Phospholipase A2 enzymes: physical structure, biological function, disease implication, chemical inhibition, and therapeutic intervention. Chem Rev 2011; 111:6130-85. [PMID: 21910409 PMCID: PMC3196595 DOI: 10.1021/cr200085w] [Citation(s) in RCA: 820] [Impact Index Per Article: 63.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Edward A. Dennis
- Department of Chemistry and Biochemistry and Pharmacology, School of Medicine, University of California, San Diego, La Jolla, California 92093-0601
| | - Jian Cao
- Department of Chemistry and Biochemistry and Pharmacology, School of Medicine, University of California, San Diego, La Jolla, California 92093-0601
| | - Yuan-Hao Hsu
- Department of Chemistry and Biochemistry and Pharmacology, School of Medicine, University of California, San Diego, La Jolla, California 92093-0601
| | - Victoria Magrioti
- Laboratory of Organic Chemistry, Department of Chemistry, University of Athens, Panepistimiopolis, Athens 15771, Greece
| | - George Kokotos
- Laboratory of Organic Chemistry, Department of Chemistry, University of Athens, Panepistimiopolis, Athens 15771, Greece
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Cao J, Hsu YH, Li S, Woods VL, Dennis EA. Lipoprotein-associated phospholipase A(2) interacts with phospholipid vesicles via a surface-disposed hydrophobic α-helix. Biochemistry 2011; 50:5314-21. [PMID: 21553808 DOI: 10.1021/bi101916w] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Lipoprotein-associated phospholipase A(2) (Lp-PLA(2)) plays important roles in both the inhibition and promotion of inflammation in human disease. It catalyzes the hydrolytic inactivation of plasma platelet activating factor (PAF) and is also known as PAF acetylhydrolase. High levels of PAF are implicated in a variety of inflammatory diseases such as asthma, necrotizing enterocolitis, and sepsis. Lp-PLA(2) also associates with lipoproteins in human plasma where it hydrolyzes oxidized phospholipids to produce pro-inflammatory lipid mediators that can promote inflammation and the development of atherosclerosis. Lp-PLA(2) plasma levels have recently been identified as a biomarker of vascular inflammation, atherosclerotic vulnerability, and future cardiovascular events. The enzyme is thus a prominent target for the development of inflammation and atherosclerosis-modulating therapeutics. While the crystallographically determined structure of the enzyme is known, the enzyme's mechanism of interaction with PAF and the function-modulating lipids in lipoproteins is unknown. We have employed peptide amide hydrogen-deuterium exchange mass spectrometry (DXMS) to characterize the association of Lp-PLA(2) with dimyristoylphosphatidylcholine (DMPC) vesicles and found that specific residues 113-120 in one of the enzyme's surface-disposed hydrophobic α-helices likely mediate liposome binding.
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Affiliation(s)
- Jian Cao
- Department of Chemistry and Biochemistry and Pharmacology, University of California, La Jolla, CA 92093-0601, USA
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