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Medicinal Research Reviews Jan 2020Inflammation is thought to play an important role in the pathogenesis of vascular diseases. Lipoprotein-associated phospholipase A2 (Lp-PLA2) mediates vascular... (Review)
Review
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.
Topics: 1-Alkyl-2-acetylglycerophosphocholine Esterase; Animals; Disease; Genetic Variation; Humans; Lipoproteins; Small Molecule Libraries; Substrate Specificity
PubMed: 31140638
DOI: 10.1002/med.21597 -
International Journal of Molecular... Jan 2023The phospholipase A2 (PLA2) superfamily of phospholipase enzymes hydrolyzes the ester bond at the sn-2 position of the phospholipids, generating a free fatty acid and a... (Review)
Review
The phospholipase A2 (PLA2) superfamily of phospholipase enzymes hydrolyzes the ester bond at the sn-2 position of the phospholipids, generating a free fatty acid and a lysophospholipid. The PLA2s are amphiphilic in nature and work only at the water/lipid interface, acting on phospholipid assemblies rather than on isolated single phospholipids. The superfamily of PLA2 comprises at least six big families of isoenzymes, based on their structure, location, substrate specificity and physiologic roles. We are reviewing the secreted PLA2 (sPLA2), cytosolic PLA2 (cPLA2), Ca-independent PLA2 (iPLA2), lipoprotein-associated PLA2 (LpPLA2), lysosomal PLA2 (LPLA2) and adipose-tissue-specific PLA2 (AdPLA2), focusing on the differences in their structure, mechanism of action, substrate specificity, interfacial kinetics and tissue distribution. The PLA2s play important roles both physiologically and pathologically, with their expression increasing significantly in diseases such as sepsis, inflammation, different cancers, glaucoma, obesity and Alzheimer's disease, which are also detailed in this review.
Topics: Humans; Isoenzymes; Phospholipases A2, Secretory; Neoplasms; Catalysis
PubMed: 36674864
DOI: 10.3390/ijms24021353 -
Autophagy Sep 2023Mitophagy, which selectively eliminates the dysfunctional and excess mitochondria by autophagy, is crucial for cellular homeostasis under stresses such as hypoxia....
Mitophagy, which selectively eliminates the dysfunctional and excess mitochondria by autophagy, is crucial for cellular homeostasis under stresses such as hypoxia. Dysregulation of mitophagy has been increasingly linked to many disorders including neurodegenerative disease and cancer. Triple-negative breast cancer (TNBC), a highly aggressive breast cancer subtype, is reported to be characterized by hypoxia. However, the role of mitophagy in hypoxic TNBC as well as the underlying molecular mechanism is largely unexplored. Here, we identified GPCPD1 (glycerophosphocholine phosphodiesterase 1), a key enzyme in choline metabolism, as an essential mediator in hypoxia-induced mitophagy. Under the hypoxic condition, we found that GPCPD1 was depalmitoylated by LYPLA1, which facilitated the relocating of GPCPD1 to the outer mitochondrial membrane (OMM). Mitochondria-localized GPCPD1 could bind to VDAC1, the substrate for PRKN/PARKIN-dependent ubiquitination, thus interfering with the oligomerization of VDAC1. The increased monomer of VDAC1 provided more anchor sites to recruit PRKN-mediated polyubiquitination, which consequently triggered mitophagy. In addition, we found that GPCPD1-mediated mitophagy exerted a promotive effect on tumor growth and metastasis in TNBC both and . We further determined that GPCPD1 could serve as an independent prognostic indicator in TNBC. In conclusion, our study provides important insights into a mechanistic understanding of hypoxia-induced mitophagy and elucidates that GPCPD1 could act as a potential target for the future development of novel therapy for TNBC patients.: ACTB: actin beta; 5-aza: 5-azacytidine; BNIP3: BCL2 interacting protein 3; BNIP3L: BCL2 interacting protein 3 like; CCCP: carbonyl cyanide m-chlorophenyl hydrazone; ChIP: chromatin immunoprecipitation; co-IP: co-immunoprecipitation; CQ: chloroquine; CsA: cyclosporine; DOX: doxorubicin; FIS1: fission, mitochondrial 1; FUNDC1: FUN14 domain containing 1; GPCPD1: glycerophosphocholine phosphodiesterase 1; HAM: hydroxylamine; HIF1A: hypoxia inducible factor 1 subunit alpha; HRE: hypoxia response element; IF: immunofluorescence; LB: lysis buffer; LC3B/MAP1LC3B: microtubule associated protein 1 light chain 3 beta; LC-MS: liquid chromatography-mass spectrometry; LYPLA1: lysophospholipase 1; LYPLA2: lysophospholipase 2; MDA231: MDA-MB-231; MDA468: MDA-MB-468; MFN1: mitofusin 1; MFN2: mitofusin 2; MKI67: marker of proliferation Ki-67; OCR: oxygen consumption rate; OMM: outer mitochondrial membrane; OS: overall survival; PalmB: palmostatin B; PBS: phosphate-buffered saline; PINK1: PTEN induced kinase 1; PRKN: parkin RBR E3 ubiquitin protein ligase; SDS: sodium dodecyl sulfate; TOMM20: translocase of outer mitochondrial membrane 20; TNBC: triple-negative breast cancer; VBIT-4: VDAC inhibitor; VDAC1: voltage dependent anion channel 1; WT: wild type.
Topics: Humans; Autophagy; Lysophospholipase; Mitophagy; Neurodegenerative Diseases; Phospholipases; Proto-Oncogene Proteins c-bcl-2; Triple Negative Breast Neoplasms; Ubiquitin-Protein Ligases; Ubiquitination; Voltage-Dependent Anion Channel 1
PubMed: 36803235
DOI: 10.1080/15548627.2023.2182482 -
Cell Metabolism Apr 2022Extracellular vesicles (EVs) including exosomes act as intercellular communicators by transferring protein and microRNA cargoes, yet the role of EV lipids remains...
Extracellular vesicles (EVs) including exosomes act as intercellular communicators by transferring protein and microRNA cargoes, yet the role of EV lipids remains unclear. Here, we show that the pro-tumorigenic action of lymphoma-derived EVs is augmented via secreted phospholipase A (sPLA)-driven lipid metabolism. Hydrolysis of EV phospholipids by group X sPLA, which was induced in macrophages of Epstein-Barr virus (EBV) lymphoma, increased the production of fatty acids, lysophospholipids, and their metabolites. sPLA-treated EVs were smaller and self-aggregated, showed better uptake, and increased cytokine expression and lipid mediator signaling in tumor-associated macrophages. Pharmacological inhibition of endogenous sPLA suppressed lymphoma growth in EBV-infected humanized mice, while treatment with sPLA-modified EVs reversed this phenotype. Furthermore, sPLA expression in human large B cell lymphomas inversely correlated with patient survival. Overall, the sPLA-mediated EV modification promotes tumor development, highlighting a non-canonical mechanistic action of EVs as an extracellular hydrolytic platform of sPLA.
Topics: Animals; Epstein-Barr Virus Infections; Extracellular Vesicles; Herpesvirus 4, Human; Humans; Lymphoma; Lymphoma, B-Cell; Mice; Phospholipases A2, Secretory
PubMed: 35294862
DOI: 10.1016/j.cmet.2022.02.011 -
Nature Chemical Biology Apr 2021Ferroptosis, triggered by discoordination of iron, thiols and lipids, leads to the accumulation of 15-hydroperoxy (Hp)-arachidonoyl-phosphatidylethanolamine...
Ferroptosis, triggered by discoordination of iron, thiols and lipids, leads to the accumulation of 15-hydroperoxy (Hp)-arachidonoyl-phosphatidylethanolamine (15-HpETE-PE), generated by complexes of 15-lipoxygenase (15-LOX) and a scaffold protein, phosphatidylethanolamine (PE)-binding protein (PEBP)1. As the Ca-independent phospholipase Aβ (iPLAβ, PLA2G6 or PNPLA9 gene) can preferentially hydrolyze peroxidized phospholipids, it may eliminate the ferroptotic 15-HpETE-PE death signal. Here, we demonstrate that by hydrolyzing 15-HpETE-PE, iPLAβ averts ferroptosis, whereas its genetic or pharmacological inactivation sensitizes cells to ferroptosis. Given that PLA2G6 mutations relate to neurodegeneration, we examined fibroblasts from a patient with a Parkinson's disease (PD)-associated mutation (fPD) and found selectively decreased 15-HpETE-PE-hydrolyzing activity, 15-HpETE-PE accumulation and elevated sensitivity to ferroptosis. CRISPR-Cas9-engineered Pnpla9 mice exhibited progressive parkinsonian motor deficits and 15-HpETE-PE accumulation. Elevated 15-HpETE-PE levels were also detected in midbrains of rotenone-infused parkinsonian rats and α-synuclein-mutant Snca mice, with decreased iPLAβ expression and a PD-relevant phenotype. Thus, iPLAβ is a new ferroptosis regulator, and its mutations may be implicated in PD pathogenesis.
Topics: Animals; Arachidonate 15-Lipoxygenase; Disease Models, Animal; Female; Ferroptosis; Group VI Phospholipases A2; Humans; Iron; Leukotrienes; Lipid Metabolism; Lipid Peroxides; Lipids; Male; Mice; Mice, Inbred C57BL; Oxidation-Reduction; Parkinson Disease; Phosphatidylethanolamine Binding Protein; Phospholipases; Phospholipids; Rats; Rats, Inbred Lew
PubMed: 33542532
DOI: 10.1038/s41589-020-00734-x -
Frontiers in Immunology 2021B cells can contribute to immune-mediated disorders. Targeting CD20 has proved to be efficacious in several B cell-mediated immunopathologies, as illustrated by the use...
BACKGROUND
B cells can contribute to immune-mediated disorders. Targeting CD20 has proved to be efficacious in several B cell-mediated immunopathologies, as illustrated by the use of rituximab, the first anti-CD20 monoclonal antibody (mAb). Following rituximab, second- and third-generation anti-CD20 mAbs have been developed and tried in immune-mediated diseases, including obinutuzumab, ocrelizumab, ofatumumab, ublituximab, and veltuzumab. However, their safety and efficacy has not been systematically reviewed.
OBJECTIVE
To evaluate safety and efficacy of obinutuzumab, ocrelizumab, ofatumumab, ublituximab, and veltuzumab for the treatment of immune-mediated disorders compared to placebo, conventional treatment or other biologics.
METHODS
The PRISMA checklist guided the reporting of the data. We searched the PubMed database between 4 October 2016 and 22 July 2021 concentrating on immune-mediated disorders.
RESULTS
The literature search identified 2220 articles. After screening titles and abstracts against the inclusion and exclusion criteria and assessing full texts, 27 articles were finally included in a narrative synthesis.
CONCLUSIONS
Obinutuzumab has shown promising results in a case series of patients with phospholipase A receptor-associated membranous nephropathy and mixed results in systemic lupus erythematosus. Ocrelizumab has been approved for the use in patients with relapsing-remitting multiple sclerosis and primary progressive multiple sclerosis. Ocrelizumab was also tested in patients with rheumatoid arthritis, demonstrating promising results, and in systemic lupus erythematosus, revealing mixed results; however, in these conditions, its use was associated with increased risk of serious infections. Ofatumumab received approval for treating patients with relapsing-remitting multiple sclerosis. Moreover, ofatumumab showed promising results in patients with anti-neutrophil cytoplasmic antibody-associated vasculitis, rheumatoid arthritis, and systemic lupus erythematosus, as well as mixed results in phospholipase A receptor-associated membranous nephropathy. Ublituximab was assessed in relapsing-remitting multiple sclerosis and neuromyelitis optica spectrum disorder, with promising results, however, the included number of patients was too small to conclude. Veltuzumab was tested in patients with immune thrombocytopenia resulting in improved platelet counts.
SYSTEMATIC REVIEW REGISTRATION
https://www.crd.york.ac.uk/prospero/, identifier CRD4201913421.
Topics: Antigens, CD20; Arthritis, Rheumatoid; Biological Products; Glomerulonephritis, Membranous; Humans; Immune System Diseases; Lupus Erythematosus, Systemic; Multiple Sclerosis; Multiple Sclerosis, Relapsing-Remitting; Phospholipases; Rituximab
PubMed: 35185862
DOI: 10.3389/fimmu.2021.788830 -
Advances in Experimental Medicine and... 2020Phospholipase C (PLC) family members constitute a family of diverse enzymes. Thirteen different family members have been cloned. These family members have unique... (Review)
Review
Phospholipase C (PLC) family members constitute a family of diverse enzymes. Thirteen different family members have been cloned. These family members have unique structures that mediate various functions. Although PLC family members all appear to signal through the bi-products of cleaving phospholipids, it is clear that each family member, and at times each isoform, contributes to unique cellular functions. This chapter provides a review of the current literature on PLC. In addition, references have been provided for more in-depth information regarding areas that are not discussed including tyrosine kinase activation of PLC. Understanding the roles of the individual PLC enzymes, and their distinct cellular functions, will lead to a better understanding of the physiological roles of these enzymes in the development of diseases and the maintenance of homeostasis.
Topics: Cell Physiological Phenomena; Humans; Isoenzymes; Type C Phospholipases
PubMed: 31646512
DOI: 10.1007/978-3-030-12457-1_9 -
Progress in Lipid Research Apr 2020Despite being discovered over 60 years ago, the precise role of phospholipase D (PLD) is still being elucidated. PLD enzymes catalyze the hydrolysis of the... (Review)
Review
Despite being discovered over 60 years ago, the precise role of phospholipase D (PLD) is still being elucidated. PLD enzymes catalyze the hydrolysis of the phosphodiester bond of glycerophospholipids producing phosphatidic acid and the free headgroup. PLD family members are found in organisms ranging from viruses, and bacteria to plants, and mammals. They display a range of substrate specificities, are regulated by a diverse range of molecules, and have been implicated in a broad range of cellular processes including receptor signaling, cytoskeletal regulation and membrane trafficking. Recent technological advances including: the development of PLD knockout mice, isoform-specific antibodies, and specific inhibitors are finally permitting a thorough analysis of the in vivo role of mammalian PLDs. These studies are facilitating increased recognition of PLD's role in disease states including cancers and Alzheimer's disease, offering potential as a target for therapeutic intervention.
Topics: Alzheimer Disease; Animals; Humans; Neoplasms; Phospholipase D
PubMed: 31830503
DOI: 10.1016/j.plipres.2019.101018 -
Handbook of Experimental Pharmacology 2020Phospholipases D (PLDs) catalyze hydrolysis of the diester bond of phospholipids to generate phosphatidic acid and the free lipid headgroup. In mammals, PLD enzymes... (Review)
Review
Phospholipases D (PLDs) catalyze hydrolysis of the diester bond of phospholipids to generate phosphatidic acid and the free lipid headgroup. In mammals, PLD enzymes comprise the intracellular enzymes PLD1 and PLD2 and possibly the proteins encoded by related genes, as well as a class of cell surface and secreted enzymes with structural homology to ectonucleotide phosphatases/phosphodiesterases as typified by autotaxin (ENPP2) that have lysoPLD activities. Genetic and pharmacological loss-of-function approaches implicate these enzymes in intra- and intercellular signaling mediated by the lipid products phosphatidic acid, lysophosphatidic acid, and their metabolites, while the possibility that the water-soluble product of their reactions is biologically relevant has received far less attention. PLD1 and PLD2 are highly selective for phosphatidylcholine (PC), whereas autotaxin has broader substrate specificity for lysophospholipids but by virtue of the high abundance of lysophosphatidylcholine (LPC) in extracellular fluids predominantly hydrolyses this substrate. In all cases, the water-soluble product of these PLD activities is choline. Although choline can be formed de novo by methylation of phosphatidylethanolamine, this activity is absent in most tissues, so mammals are effectively auxotrophic for choline. Dietary consumption of choline in both free and esterified forms is substantial. Choline is necessary for synthesis of the neurotransmitter acetylcholine and of the choline-containing phospholipids PC and sphingomyelin (SM) and also plays a recently appreciated important role as a methyl donor in the pathways of "one-carbon (1C)" metabolism. This review discusses emerging evidence that some of the biological functions of these intra- and extracellular PLD enzymes involve generation of choline with a particular focus on the possibility that these choline and PLD dependent processes are dysregulated in cancer.
Topics: Animals; Choline; Humans; Hydrolysis; Neoplasms; Phosphatidic Acids; Phospholipase D; Signal Transduction
PubMed: 32086667
DOI: 10.1007/164_2019_320 -
Nature Immunology Mar 2023How lipidome changes support CD8 effector T (T) cell differentiation is not well understood. Here we show that, although naive T cells are rich in polyunsaturated...
How lipidome changes support CD8 effector T (T) cell differentiation is not well understood. Here we show that, although naive T cells are rich in polyunsaturated phosphoinositides (PIP with 3-4 double bonds), T cells have unique PIP marked by saturated fatty acyl chains (0-2 double bonds). PIP are precursors for second messengers. Polyunsaturated phosphatidylinositol bisphosphate (PIP) exclusively supported signaling immediately upon T cell antigen receptor activation. In late T cells, activity of phospholipase C-γ1, the enzyme that cleaves PIP into downstream mediators, waned, and saturated PIP became essential for sustained signaling. Saturated PIP was more rapidly converted to PIP with subsequent recruitment of phospholipase C-γ1, and loss of saturated PIP impaired T cell fitness and function, even in cells with abundant polyunsaturated PIP. Glucose was the substrate for de novo PIP synthesis, and was rapidly utilized for saturated PIP generation. Thus, separate PIP pools with distinct acyl chain compositions and metabolic dependencies drive important signaling events to initiate and then sustain effector function during CD8+ T cell differentiation.
Topics: Phosphatidylinositols; Phosphatidylinositol Phosphates; Signal Transduction; Type C Phospholipases; CD8-Positive T-Lymphocytes
PubMed: 36732424
DOI: 10.1038/s41590-023-01419-y