The intracoronary artery injection of platelet rich plasma activated with platelet activating factor into thrombocytopenic dogs produced a significantly greater increase in coronary artery blood flow than the injection of either nonactivated platelet rich plasma or platelet depleted plasma to which platelet activating factor was added. The platelet activating factor receptor is a gprotein coupled receptor which binds platelet activating factor the paf receptor shows structural characteristics of the rhodopsin mim 180380 gene family and binds platelet activating factor paf. Plateletactivating factor pafantagonists of natural. Plateletactivating factor paf is a potent phospholipid mediator, which has previously reported biological activities in bc progression and osteoclast differentiation by activating its receptor. Plateletactivating factor is a ubiquitous and potent lipid inflammatory mediator 12. Paf is considered a potential relevant mediator in allergic rhinitis, with a key. Type 1 diabetes is caused by autoimmune destruction of the. Emphasis is given on recent results about a new class of the socalled metalbased inhibitors of paf. Platelets interact with several coagulation factors, while the coagulation product thrombin is a potent platelet activating agonist. Pdf on nov 1, 1990, s m prescott and others published plateletactivating factor find, read and cite all the research you need on. Role of plateletactivating factor paf in the initiation. The single platelet activating factor receptor pafr is a gprotein coupled receptor present in the plasma and nuclear membranes of the majority of cells of the vascular and innate immune system that activates a variety of pathways involved in inflammation, oncogenic transformation, tumor growth, angiogenesis and metastasis. To generate paf, phospholipase a 2 removes fatty acid in the sn2 position of the estertype membrane phospholipid, followed by acetylation. Thus, the paf signaling system is a point of convergence at which.
Platelet activating factor synonyms, platelet activating factor pronunciation, platelet activating factor translation, english dictionary definition of platelet activating factor. Platelet activating factor is a ubiquitous and potent lipid inflammatory mediator 12. Initial release from internal source and subsequent. Platelet activating factor receptor pafr plays a critical role in regulating pulmonary responses to infection in conditions, such as. Compare platelet activating factor elisa kits from leading suppliers on biocompare. Platelet activating factor paf plays an important role in the pathogenesis of several types of tumors.
Using a receptor preparation of rabbit platelet membranes, we identified a. Plateletactivating factor paf is a phospholipid that was discovered as a platelet agglutinating factor derived from rabbit basophils and as a depressor substance derived from the renal medulla. Arecent study has suggested that it mayenhance leukotriene c4ltc4releasefromeosinophils14, andinanimalmodels, inhalation ofpafhascaused anincrease in the percentage of. Plateletactivating factor paf is a phospholipid mediator that exhibits diverse and potent effects on many cell types 1. Paf is a potent mediator of hypersensitivity and inflammatory reactions 2. In this study, patients with anaphylactic reactions were found to. The ginsenosides are also believed to have the potential to inhibit platelet activating factor. Platelets interact with several coagulation factors, while the coagulation product thrombin is a potent plateletactivating agonist.
Platelet activating factor, also known as paf, pafacether or agepc acetylglyceryletherphosphorylcholine, is a potent phospholipid activator and mediator of many leukocyte functions, platelet aggregation and degranulation, inflammation, and anaphylaxis. The plateletactivating factor signaling system and its regu. Forty years since the structural elucidation of platelet. Elevated levels of platelet activating factor and its. Plateletactivating factor 1oalkyl2acetylsnglycero3phosphocholine also known as paf, was discovered by the french immunologist jacques benveniste 19352004. This period saw a burst in research activity focused predominantly on the effect of paf in various organs. Variation in plasma plateletactivating factor degradation a.
Oxidative modification of lowdensity lipoprotein, which plays an important role in atherogenesis. Recently, a number of studies have examined the association between aspirin resistance and several receptors on the surface of platelets, sup21 such as genetic polymorphisms of platelet membrane glycoproteins, genetic mutations of tbxa2r, the plateletactivating factor acetylhydrolase, and coagulation factor xiii. The plateletactivating factor signaling system and its. A factor which, like prostaglandins and leukotrienes, is released from cell membranes. Abstractwe studied the expression of lipoproteinassociated phospholipase a 2 lppla 2, an enzyme capable of hydrolyzing plateletactivating factor paf, paflike phospholipids, and polarmodified phosphatidylcholines, in human and rabbit atherosclerotic lesions. In contrast, there have been few reports ofits effects oneosinophils. The bioactivity of paf is effectively and tightly regulated. Paf is a phospholipid 10alkyl2acetylsnglycero3phosphorylcholine that has been implicated as a mediator in diverse pathologic processes. Plateletactivating factorpaf is a potent lipid mediator of inflammation and asthma. In 1972, the term plateletactivating factor paf was coined by benveniste, henson, and cochrane.
Nuclear factor b dependency of platelet activating factor induced angiogenesis1 hyunmi ko, kook heon seo, suji han, kyu youn ahn, ilhwan choi, gou young koh, hernku lee, myung suk ra, and suhnyoung im2 department of biological sciences, the institute of basic sciences hm. It is released from multiple cells of the immune system, such as eosinophils, neutrophils, and mast cells, and also exerts its effect on most of them upon specific binding to its receptor, becoming a pleiotropic mediator. Plateletactivating factor receptor pafr is a g q g 11coupledprotein receptor that. Plateletactivating factor an overview sciencedirect. In this study, patients with anaphylactic reactions were found to have. Plateletactivating factor paf is the commonly used name for a group of potent. Pdf enzymatic pathways for plateletactivating factor, related alkyl. Modulation of tumorassociated macrophages tam phenotype. In plasma, its inactivation to lysoplateletactivating factor is catalyzed by a specific, lipoproteinassociated acetylhydrolase. Plateletactivating factor paf definition of platelet. A minute, nonnucleated, disklike cytoplasmic body found in the blood plasma of mammals that is derived from a megakaryocyte and functions to promote. Synthesis of plateletactivating factor by polymorphonuclear.
Opposing effects of plateletactivating factor and lyso. Streptococcus pneumoniae anchor to activated human cells. Plateletactivating factor an overview sciencedirect topics. Platelet activating factor binds to a unique gprotein coupled seven transmembrane receptor and triggers multiple intracellular signaling pathways. Degradation of platelet activating factor was examined in an optimized assay of acetylhydrolase activity and in relation to the in vitro plasma halflife of platelet activating factor. Modulation of tumorassociated macrophages tam phenotype by. Plateletactivating factor paf is a potent inflammatory mediator that mimics many of the features of asthma, including eosinophil recruitment and activation and induction of ahr. Plateletactivating factor paf is a potent inflammatory mediator that mimics many of the features of asthma, including eosinophil recruitment and activation and. The biological effects of paf are mediated by the paf receptor pafr, which can be expressed by tumor cells and host cells that infiltrate the tumor microenvironment. Incorporation of3hacetate into a polar lipid is depen dentontheconcentration ofthrombin.
Slideshare uses cookies to improve functionality and performance, and to provide you with relevant advertising. Due to its role, it has been also considered as a hormone or a primitiveuniversal cellular biological regulator 12. Platelet activating factor is a potent inflammatory mediator. In 1972, the term plateletactivating factor paf was coined by benveniste, henson, and. Role of platelet activating factor paf in the initiation of the decidual reaction in the rat in reproduction. Paf is considered a potential relevant mediator in allergic rhinitis, with a. Pdf plateletactivating factor paf in allergic rhinitis. Chemistry several molecular species of plateletactivating factor have been identified which vary in the length of the oalkyl side chain. Plateletactivating factor apotentchemotactic andchemokineticfactorfor humaneosinophils a. Plateletactivating factor paf, 10alkyl2acetylsn glycero3phosphocholine is a potent biological mediator that exerts its effects in a variety of cells and. Paf is a phospholipid 10alkyl2acetylsnglycero3phosphorylcholine that has been implicated as a mediator in diverse. Plateletactivating factor paf, 10alkyl2acetylsnglycero3phosphocholine is a potent mediator of inflammation that causes neutrophil activation, increased vascular permeability, vasodilation, and bronchoconstriction in addition to platelet activation. Platelet activating factor paf, 10alkyl2acetylsnglycero3phosphocholine is a potent mediator of inflammation that causes neutrophil activation, increased vascular permeability, vasodilation, and bronchoconstriction in addition to platelet activation.
Streptococcus pneumoniae anchor to activated human cells by. In the present study, we investigated the role of pafr expressed by leukocytes that infiltrate two types of tumors, one. Streptococcus pneumoniae anchor to activated human cells by the receptor for plateletactivating factor. It is a potent cause of inflammation and an activator of several cell types of the immune system. The plateletactivating factor receptor is a gprotein coupled receptor which binds plateletactivating factor the paf receptor shows structural characteristics of the rhodopsin mim 180380 gene family and binds plateletactivating factor paf.
Plateletactivating factor paf is a potent, bioactive phospholipid that acts on multiple cells and tissues through its g proteincoupled receptor gpcr. Plateletactivating factor the journal of lipid research. Nuclear factor b dependency of plateletactivating factorinduced angiogenesis1 hyunmi ko, kook heon seo, suji han, kyu youn ahn, ilhwan choi, gou young koh, hernku lee, myung suk ra, and suhnyoung im2 department of biological sciences, the institute of basic sciences hm. Jan 17, 2015 platelet activating factor is a potent biological mediator that exerts its effects in a variety of cells and tissues. Coagulation factors, phosphatidylserine, platelet receptors, thrombin summary platelet activation and blood coagulation are complementary, mutually dependent processes in haemostasis and thrombosis. Plateletactivating factor paf is a proinflammatory lipid mediator possessing a unique 1oalkyl glycerophospholipid gpc backbone. These studies introduced the research world to paf, which is now recognised as a potent phospholipid mediator. In the present study, we investigated the role of pafr expressed by leukocytes that infiltrate two types of. Platelet activating factor acetylhydrolase pafah is a family of enzymes, the most abundant of which is the plasma form, also called lipoproteinassociated phospholipase a2 lppla2 6. The effect of paf and its antagonists was further intensively studied in vitro on isolated platelets, leucocytes, macrophages and endothelial cells. Apr 11, 2019 platelet activating factor receptor pafr plays a critical role in regulating pulmonary responses to infection in conditions, such as chronic obstructive pulmonary disease and asthma. Platelet activating factor paf is a low molecular weight, etherlinked phospholipid originally identified as a soluble factor, released from sensitized rabbit basophils during ige anaphylaxis, that was capable of aggregating rabbit platelets 1, 2.
Plateletactivating factor is identified as 1oalkyl2acetylsnglycero3phosphocholine 12. These, plasma lyso platelet activating factor and serum lipids, were measured in 12 men with acute myocardial infarction at presentation and at 2 and 7 days later. The role of plateletactivating factor in pathogenesis of. Plateletactivating factor paf is a lipid mediator involved in several allergic reactions. The effect of paf and its antagonists was further intensively studied in vitro on isolated platelets, leucocytes. The platelet activating factor paf signaling cascade in.
Data extraction, synthesis, and summary paf, a phospholipid signaling molecule, transmits outsidein signals to intracellular transduction systems and effector mechanisms in a variety of cell types, including key cells of the innate immune and hemostatic systems. Plateletactivating factor and related lipid mediators springerlink. The ginsenosides are also believed to have the potential to inhibit plateletactivating factor. The plateletactivating factor paf signaling cascade consists of paf and paflike lipids pafll that are specific, structurallydefined ligands for a gprotein coupled receptor, the paf receptor pafr, which has restricted expression on key target cells of the inflammatory, immune, and hemostatic systems. Platelet activating factor in allergies sage journals. Characterization of a plateletactivating factor receptor. Platelet activating factor paf is a potent inflammatory mediator that mimics many of the features of asthma, including eosinophil recruitment and activation and induction of ahr. At first, results of organic compounds natural and synthetic ones and specific and nonspecific as inhibitors of paf are reported. Kawasaki disease kd is a systemic vasculitis in children, which is related to inflammation and abnormal activation of immune system. Paf receptors plateletactivating factor receptor tocris.
Plateletactivating factor receptor introduction bps. Plateletactivating factor, paf acetylhydrolase, and severe. The structure of paf was later elucidated by demopoulos, pinckard, and hanahan in 1979. Platelet activating factor paf at 100nm induced a biphasic calcium response in microglia culture. Forty years since the structural elucidation of plateletactivating. Streptococcus pneumoniae anchor to activated human cells by the receptor for platelet activating factor.
This study aimed to investigate diagnosis and prognostic value of serum paf and pafah in kd. Plateletactivating factor is a biologically potent phospholipid that may mediate cell damage in patients with myocardial ischemia. Variation in plasma plateletactivating factor degradation. Plateletactivating factor, also known as paf, paf acether or agepc acetylglyceryletherphosphorylcholine, is a potent phospholipid activator and mediator of many leukocyte functions, including platelet aggregation and. Platelet activating factor receptor pafr is a g q g 11coupledprotein receptor that has a role in a wide range of biological processes such as vasodilation, superoxide formation, cell proliferation, angiogenesis and regulation of the inflammatory response. Plateletactivating factor acetylglyceryletherphosphorylcholine. Platelet activating factor, paf acetylhydrolase, and severe anaphylaxis n engl j med 358. Because lipoprotein levels decrease after myocardial infarction, a possible reduction was suspected to occur in plasma. Plateletactivating factor financial definition of platelet. Plateletactivating factor paf is an anaphylactic mediator that is degraded in the blood by the enzyme paf acetylhydrolase. It is also involved in changes to vascular permeability, the oxidative burst.
Plateletactivating factor and the release of a platelet. The plasmatic pafah is constitutively active and circulates bound to ldl, hdl and other lipoproteins and catalyses the hydrolysis of the sn2. Plateletactivating factor is a potent inflammatory mediator. Platelet activating factor paf is a lipid mediator involved in several allergic reactions.
In 1972, benveniste demonstrated that this factor was released from basophils. Plateletactivating factor paf plays an important role in the pathogenesis of several types of tumors. Paf is formed by a smaller number of cell types than the. The single plateletactivating factor receptor pafr is a gprotein coupled receptor present in the plasma and nuclear membranes of the majority of cells of the vascular and innate immune system that activates a variety of pathways involved in inflammation, oncogenic transformation, tumor growth, angiogenesis and metastasis. Plateletactivating factor, paf acetylhydrolase, and. Platelet activating factor paf is a potent phospholipid mediator, which has previously reported biological activities in bc progression and osteoclast differentiation by activating its receptor. Its alkyl group is connected by an ether linkage at the c1 carbon to a sixteen carbon chain.
Platelet activating factor paf and its acetylhydrolase pafah may play an important role in the pathogenesis of kd. Platelet activating factor platelet activating factors are a family of proinflammatory phospho lipids that are synthesized throughout the body by specific stimulation of various cell types such as platelets, macrophages, monocytes, eosinophils, basophils, and endothelial cells. Paf is not stored but is rapidly generated via enzymatic acetylation of the precursor 1 o hexadecyl2hydroxy sn glycero3phosphocholine lysopaf. Platelet activating factor paf is an anaphylactic mediator that is degraded in the blood by the enzyme paf acetylhydrolase.