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Biomolecules May 2023Phospholipases are essential intermediaries that work as hydrolyzing enzymes of phospholipids (PLs), which represent the most abundant species contributing to the... (Review)
Review
Phospholipases are essential intermediaries that work as hydrolyzing enzymes of phospholipids (PLs), which represent the most abundant species contributing to the biological membranes of nervous cells of the healthy human brain. They generate different lipid mediators, such as diacylglycerol, phosphatidic acid, lysophosphatidic acid, and arachidonic acid, representing key elements of intra- and inter-cellular signaling and being involved in the regulation of several cellular mechanisms that can promote tumor progression and aggressiveness. In this review, it is summarized the current knowledge about the role of phospholipases in brain tumor progression, focusing on low- and high-grade gliomas, representing promising prognostic or therapeutic targets in cancer therapies due to their influential roles in cell proliferation, migration, growth, and survival. A deeper understanding of the phospholipases-related signaling pathways could be necessary to pave the way for new targeted therapeutic strategies.
Topics: Humans; Phospholipases; Brain Neoplasms; Brain; Glioma; Phospholipids
PubMed: 37238668
DOI: 10.3390/biom13050798 -
Cell Reports Methods Apr 2022Vesicle exo- and endocytosis mediate important biological functions, including synaptic transmission. In this issue of , Seong J. An et al. found that the fluorescently...
Vesicle exo- and endocytosis mediate important biological functions, including synaptic transmission. In this issue of , Seong J. An et al. found that the fluorescently tagged C2 domain of phospholipase A binds to membrane phosphatidylcholine and thus labels vesicle membrane, allowing for super-resolution and electron microscopic visualization of vesicle trafficking.
Topics: Synaptic Vesicles; Phospholipases A2; Endocytosis; Synaptic Transmission; Multimodal Imaging
PubMed: 35497501
DOI: 10.1016/j.crmeth.2022.100206 -
Journal of Bacteriology Aug 2017causes health care-associated opportunistic infections that can be difficult to treat due to a high incidence of antibiotic resistance. One of the many secreted...
causes health care-associated opportunistic infections that can be difficult to treat due to a high incidence of antibiotic resistance. One of the many secreted proteins of is the PhlA phospholipase enzyme. Genes involved in the production and secretion of PhlA were identified by screening a transposon insertion library for phospholipase-deficient mutants on phosphatidylcholine-containing medium. Mutations were identified in four genes (, , , and ) that are involved in the flagellum-dependent PhlA secretion pathway. An additional phospholipase-deficient isolate harbored a transposon insertion in the gene encoding a predicted serine -acetyltransferase required for cysteine biosynthesis. The requirement for extracellular phospholipase activity was confirmed using a fluorogenic phospholipase substrate. Phospholipase activity was restored to the mutant by the addition of exogenous l-cysteine or -acetylserine to the culture medium and by genetic complementation. Additionally, transcript levels were decreased 6-fold in bacteria lacking and were restored with added cysteine, indicating a role for cysteine-dependent transcriptional regulation of phospholipase activity. mutants also exhibited a defect in swarming motility that was correlated with reduced levels of and flagellar regulator gene transcription. Together, these findings suggest a model in which cysteine is required for the regulation of both extracellular phospholipase activity and surface motility in is known to secrete multiple extracellular enzymes, but PhlA is unusual in that this protein is thought to be exported by the flagellar transport apparatus. In this study, we demonstrate that both extracellular phospholipase activity and flagellar function are dependent on the cysteine biosynthesis pathway. Furthermore, a disruption of cysteine biosynthesis results in decreased and flagellar gene transcription, which can be restored by supplying bacteria with exogenous cysteine. These results identify a previously unrecognized role for CysE and cysteine in the secretion of phospholipase and in bacterial motility.
Topics: Culture Media; Cysteine; DNA Transposable Elements; Gene Expression Profiling; Gene Knockout Techniques; Genetic Complementation Test; Locomotion; Mutagenesis, Insertional; Phospholipases; Serine; Serine O-Acetyltransferase; Serratia marcescens
PubMed: 28559296
DOI: 10.1128/JB.00159-17 -
Renal Failure Dec 2023Hepatitis B virus-associated glomerulonephritis (HBV-GN) is one of the main types of secondary glomerular diseases, and podocyte injury is an important pathogenic...
INTRODUCTION
Hepatitis B virus-associated glomerulonephritis (HBV-GN) is one of the main types of secondary glomerular diseases, and podocyte injury is an important pathogenic mechanism of HBV-GN, participating in the occurrence and development of HBV-GN. However, the specific mechanism of podocyte injury remains to be studied.
METHODS
Human renal podocytes cultured were divided into six groups. The podocyte morphology was observed under a transmission electron microscope, and the expression of M-type phospholipase A receptor (M-PLAR) on the podocyte membrane was observed by indirect immunofluorescence staining under a fluorescence microscope. The pyroptosis rate and reactive oxygen species (ROS) of podocytes were assessed by FLICA/PI double staining and flow cytometry. Western blot (WB) and quantitative real-time PCR (qPCR) were used to determine the expression of PLAR, nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3), apoptosis-associated speck-like protein containing card (ASC), caspase-1, IL-1β, and IL-18.
RESULTS
Hepatitis B virus X (HBx) transfected into human renal podocytes induced the overexpression of PLAR. Moreover, the overexpressed PLAR combined with secretory phospholipase A group IB (sPLA-IB) aggravated podocyte injury and increased the pyroptosis rate. In addition, the expression of ROS, the NLRP3 inflammasome and downstream inflammatory factors was increased. In contrast, after inhibiting the expression of PLAR and ROS, podocyte damage was alleviated, and the pyroptosis rate and the expression of genes related to the ROS-NLRP3 signaling pathway were decreased.
CONCLUSION
HBx-induced PLAR overexpression on the podocyte membrane can significantly upregulate the ROS-NLRP3 signaling pathway, thereby mediating podocyte pyroptosis.
Topics: Humans; Podocytes; NLR Family, Pyrin Domain-Containing 3 Protein; Pyroptosis; Reactive Oxygen Species; Signal Transduction; Phospholipases; Polyesters
PubMed: 36698326
DOI: 10.1080/0886022X.2023.2170808 -
Molecules (Basel, Switzerland) Apr 2022Phospholipase A (PLA) is an enzyme that cleaves an ester bond at the -1 position of glycerophospholipids, producing a free fatty acid and a lysophospholipid. PLA... (Review)
Review
Phospholipase A (PLA) is an enzyme that cleaves an ester bond at the -1 position of glycerophospholipids, producing a free fatty acid and a lysophospholipid. PLA activities have been detected both extracellularly and intracellularly, which are well conserved in higher eukaryotes, including fish and mammals. All extracellular PLAs belong to the lipase family. In addition to PLA activity, most mammalian extracellular PLAs exhibit lipase activity to hydrolyze triacylglycerol, cleaving the fatty acid and contributing to its absorption into the intestinal tract and tissues. Some extracellular PLAs exhibit PLA activities specific to phosphatidic acid (PA) or phosphatidylserine (PS) and serve to produce lysophospholipid mediators such as lysophosphatidic acid (LPA) and lysophosphatidylserine (LysoPS). A high level of PLA activity has been detected in the cytosol fractions, where PA-PLA/DDHD1/iPLA was responsible for the activity. Many homologs of PA-PLA and PLA have been shown to exhibit PLA activity. Although much has been learned about the pathophysiological roles of PLA molecules through studies of knockout mice and human genetic diseases, many questions regarding their biochemical properties, including their genuine in vivo substrate, remain elusive.
Topics: Animals; Lipase; Lysophospholipids; Mammals; Mice; Phospholipases A1
PubMed: 35458682
DOI: 10.3390/molecules27082487 -
Advances in Biological Regulation Jan 2018The phospholipase A superfamily of enzymes plays a significant role in the development and progression of numerous inflammatory diseases. Through their catalytic action... (Review)
Review
The phospholipase A superfamily of enzymes plays a significant role in the development and progression of numerous inflammatory diseases. Through their catalytic action on membrane phospholipids, phospholipases are the upstream regulators of the eicosanoid pathway releasing free fatty acids for cyclooxygenases, lipoxygenases, and cytochrome P450 enzymes which produce various well-known inflammatory mediators including leukotrienes, thromboxanes and prostaglandins. Elucidating the association of phospholipases A with the membrane, the extraction and binding of phospholipid substrates, and their interactions with small-molecule inhibitors is crucial for the development of new anti-inflammatory therapeutics. Studying phospholipases has been challenging because they act on the surface of cellular membranes and micelles. Multidisciplinary approaches including hydrogen/deuterium exchange mass spectrometry, molecular dynamics simulations, and other computer-aided drug design techniques have been successfully employed by our laboratory to study interactions of phospholipases with membranes, phospholipid substrates and inhibitors. This review summarizes the application of these techniques to study four human recombinant phospholipases A.
Topics: Cell Membrane; Deuterium Exchange Measurement; Humans; Mass Spectrometry; Molecular Dynamics Simulation; Phospholipases A2; Phospholipids
PubMed: 29248300
DOI: 10.1016/j.jbior.2017.10.009 -
The Journal of Biological Chemistry Dec 2021Many studies have confirmed the enzymatic activity of a mammalian phosphatidylcholine (PC) phospholipase C (PLC) (PC-PLC), which produces diacylglycerol (DAG) and...
Many studies have confirmed the enzymatic activity of a mammalian phosphatidylcholine (PC) phospholipase C (PLC) (PC-PLC), which produces diacylglycerol (DAG) and phosphocholine through the hydrolysis of PC in the absence of ceramide. However, the protein(s) responsible for this activity have never yet been identified. Based on the fact that tricyclodecan-9-yl-potassium xanthate can inhibit both PC-PLC and sphingomyelin synthase (SMS) activities, and SMS1 and SMS2 have a conserved catalytic domain that could mediate a nucleophilic attack on the phosphodiester bond of PC, we hypothesized that both SMS1 and SMS2 might have PC-PLC activity. In the present study, we found that purified recombinant SMS1 and SMS2 but not SMS-related protein have PC-PLC activity. Moreover, we prepared liver-specific Sms1/global Sms2 double-KO mice. We found that liver PC-PLC activity was significantly reduced and steady-state levels of PC and DAG in the liver were regulated by the deficiency, in comparison with control mice. Using adenovirus, we expressed Sms1 and Sms2 genes in the liver of the double-KO mice, respectively, and found that expressed SMS1 and SMS2 can hydrolyze PC to produce DAG and phosphocholine. Thus, SMS1 and SMS2 exhibit PC-PLC activity in vitro and in vivo.
Topics: Animals; COS Cells; Chlorocebus aethiops; Liver; Mice; Mice, Knockout; Phosphatidylcholines; Protein Domains; Recombinant Proteins; Transferases (Other Substituted Phosphate Groups); Type C Phospholipases
PubMed: 34774525
DOI: 10.1016/j.jbc.2021.101398 -
Medical Archives (Sarajevo, Bosnia and... Dec 2022Toxoplasma gondii, a protozoan parasite with a worldwide distribution, is considered to infect one-third of all humans. many species. The intracellular parasite...
BACKGROUND
Toxoplasma gondii, a protozoan parasite with a worldwide distribution, is considered to infect one-third of all humans. many species. The intracellular parasite Toxoplasma gondii causes toxoplasmosis. Numerous physiological abnormalities are documented in toxoplasmosis-infected women.
OBJECTIVE
This study aims to demonstrate the connection between cyclophilins, the phospholipase enzyme, and latent toxoplasmosis.
METHODS
The research was carried out between January 2022 and June 2022. out of 150 patients had blood samples drawn, 250 had serum samples drawn from women with toxoplasma gondi infection, and 50 had healthy samples drawn from Hila city, Iraq. To exclude subjects who had any medical disorders, information from the subjects was gathered via an interviewer-managed questionnaire. ELISA was used to examine the serum. Results: About 250 samples from women with infertility were infected with Toxoplasma gondii overall (24%) Enzyme-Linked Immunosorbent Assay was utilized to evaluate the levels of phospholipase and cyclophilin, while automated VIDAS family instruments were employed to determine the qualitative and quantitative anti-Toxoplasma-IgG-tests (ELISA). Since there was a substantial difference in the statistical analysis and a significant difference in the cyclophilin protein, parasite infection changed the quantity of the enzyme phospholipase.
CONCLUSION
This study put forth the theory that toxoplasmosis infection. Our investigation showed that patients with toxoplasma Gondi infection had higher levels of cyclophilins and phospholipase than control subjects.
Topics: Humans; Female; Cyclophilins; Phospholipases; Toxoplasmosis; Toxoplasma; Enzyme-Linked Immunosorbent Assay
PubMed: 36937607
DOI: 10.5455/medarh.2022.76.443-446 -
Advances in Immunology 2016Within the phospholipase A (PLA) family that hydrolyzes phospholipids to yield fatty acids and lysophospholipids, secreted PLA (sPLA) enzymes comprise the largest group... (Review)
Review
Within the phospholipase A (PLA) family that hydrolyzes phospholipids to yield fatty acids and lysophospholipids, secreted PLA (sPLA) enzymes comprise the largest group containing 11 isoforms in mammals. Individual sPLAs exhibit unique tissue or cellular distributions and enzymatic properties, suggesting their distinct biological roles. Although PLA enzymes, particularly cytosolic PLA (cPLAα), have long been implicated in inflammation by driving arachidonic acid metabolism, the precise biological roles of sPLAs have remained a mystery over the last few decades. Recent studies employing mice gene-manipulated for individual sPLAs, in combination with mass spectrometric lipidomics to identify their target substrates and products in vivo, have revealed their roles in diverse biological events, including immunity and associated disorders, through lipid mediator-dependent or -independent processes in given microenvironments. In this review, we summarize our current knowledge of the roles of sPLAs in various immune responses and associated diseases.
Topics: Animals; Animals, Genetically Modified; Arachidonic Acid; Humans; Immune System Diseases; Inflammation; Lipid Metabolism; Mice; Multigene Family; Phospholipases A2, Secretory
PubMed: 27769509
DOI: 10.1016/bs.ai.2016.05.001 -
Pharmacology & Therapeutics May 2023Glycerophospholipids are major components of cell membranes and consist of a glycerol backbone esterified with one of over 30 unique fatty acids at each of the sn-1 and... (Review)
Review
Glycerophospholipids are major components of cell membranes and consist of a glycerol backbone esterified with one of over 30 unique fatty acids at each of the sn-1 and sn-2 positions. In addition, in some human cells and tissues as much as 20% of the glycerophospholipids contain a fatty alcohol rather than an ester in the sn-1 position, although it can also occur in the sn-2 position. The sn-3 position of the glycerol backbone contains a phosphodiester bond linked to one of more than 10 unique polar head-groups. Hence, humans contain thousands of unique individual molecular species of phospholipids given the heterogeneity of the sn-1 and sn-2 linkage and carbon chains and the sn-3 polar groups. Phospholipase A (PLA) is a superfamily of enzymes that hydrolyze the sn-2 fatty acyl chain resulting in lyso-phospholipids and free fatty acids that then undergo further metabolism. PLA's play a critical role in lipid-mediated biological responses and membrane phospholipid remodeling. Among the PLA enzymes, the Group VIA calcium-independent PLA (GVIA iPLA), also referred to as PNPLA9, is a fascinating enzyme with broad substrate specificity and it is implicated in a wide variety of diseases. Especially notable, the GVIA iPLA is implicated in the sequelae of several neurodegenerative diseases termed "phospholipase A-associated neurodegeneration" (PLAN) diseases. Despite many reports on the physiological role of the GVIA iPLA, the molecular basis of its enzymatic specificity was unclear. Recently, we employed state-of-the-art lipidomics and molecular dynamics techniques to elucidate the detailed molecular basis of its substrate specificity and regulation. In this review, we summarize the molecular basis of the enzymatic action of GVIA iPLA and provide a perspective on future therapeutic strategies for PLAN diseases targeting GVIA iPLA.
Topics: Humans; Calcium; Glycerol; Neurodegenerative Diseases; Phospholipases A2; Phospholipids; Glycerophospholipids; Phospholipases A2, Calcium-Independent
PubMed: 36990122
DOI: 10.1016/j.pharmthera.2023.108395