共查询到20条相似文献,搜索用时 15 毫秒
1.
Christabel Fung-Yih Ho Nadia Binte Ismail Joled Kong-Ze Koh Saravanan Gunaseelan Yi-Hua Low Yee-Kong Ng John Jia-En Chua Wei-Yi Ong 《Neurochemical research》2018,43(8):1587-1598
Arachidonic acid and docosahexaenoic acid (DHA) released by the action of phospholipases A2 (PLA2) on membrane phospholipids may be metabolized by lipoxygenases to the anti-inflammatory mediators lipoxin A4 (LXA4) and resolvin D1 (RvD1), and these can bind to a common receptor, formyl-peptide receptor 2 (FPR2). The contribution of this receptor to axonal or dendritic outgrowth is unknown. The present study was carried out to elucidate the distribution of FPR2 in the rat CNS and its role in outgrowth of neuronal processes. FPR2 mRNA expression was greatest in the brainstem, followed by the spinal cord, thalamus/hypothalamus, cerebral neocortex, hippocampus, cerebellum and striatum. The brainstem and spinal cord also contained high levels of FPR2 protein. The cerebral neocortex was moderately immunolabelled for FPR2, with staining mostly present as puncta in the neuropil. Dentate granule neurons and their axons (mossy fibres) in the hippocampus were very densely labelled. The cerebellar cortex was lightly stained, but the deep cerebellar nuclei, inferior olivary nucleus, vestibular nuclei, spinal trigeminal nucleus and dorsal horn of the spinal cord were densely labelled. Electron microscopy of the prefrontal cortex showed FPR2 immunolabel mostly in immature axon terminals or ‘pre-terminals’, that did not form synapses with dendrites. Treatment of primary hippocampal neurons with the FPR2 inhibitors, PBP10 or WRW4, resulted in reduced lengths of axons and dendrites. The CNS distribution of FPR2 suggests important functions in learning and memory, balance and nociception. This might be due to an effect of FPR2 in mediating arachidonic acid/LXA4 or DHA/RvD1-induced axonal or dendritic outgrowth. 相似文献
2.
Phospholipase A2 (PLA2) is a family of enzymes playing diverse roles in lipid signaling in neurons and glia cells. In this study, we examined the expression of subtypes of PLA2 in the cerebellum using immunolabeling and in situ hybridization methods. Two Ca2+-dependent cytosolic subtypes (cPLA2α and cPLA2β), one Ca2+-independent cytosolic subtype (iPLA2), and two secretory subtypes (sPLA2IIA and sPLA2V) were detected in the cerebellum. cPLA2α is present in somata and dendrites of Purkinje cells, while sPLA2IIA is associated with the endoplasmic reticulum in perinuclear regions of Purkinje cell somata. iPLA2 is present in granule cells, stellate cells and also in the nucleus of Purkinje cells. In addition, cPLA2β is localized in granule cells, and sPLA2V in Bergmann glia cells. These results provide an important basis for identifying functional roles of PLA2s in the cerebellum. 相似文献
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Phospholipases A2 (PLA2s) are a diverse family of lipolytic enzymes which hydrolyze the acyl bond at the sn-2 position of glycerophospholipids to produce free fatty acids and lysophospholipids. These products are precursors of bioactive eicosanoids and platelet-activating factor which have been implicated in pathological states of numerous acute and chronic neurological disorders. To date, more than 27 isoforms of PLA2 have been found in the mammalian system which can be classified into four major categories: secretory PLA2, cytosolic PLA2, Ca2+-independent PLA2, and platelet-activating factor acetylhydrolases. Multiple isoforms of PLA2 are found in the mammalian spinal cord. Under physiological conditions, PLA2s are involved in diverse cellular responses, including phospholipid digestion and metabolism, host defense, and signal transduction. However, under pathological situations, increased PLA2 activity, excessive production of free fatty acids and their metabolites may lead to the loss of membrane integrity, inflammation, oxidative stress, and subsequent neuronal injury. There is emerging evidence that PLA2 plays a key role in the secondary injury process after traumatic spinal cord injury. This review outlines the current knowledge of the PLA2 in the spinal cord with an emphasis being placed on the possible roles of PLA2 in mediating the secondary SCI. 相似文献
5.
Yanxiao Xiang Lin Chen Huiqing Liu Xiaoqian Liu Xinbing Wei Baozhu Sun Tian Wang Xiumei Zhang 《PloS one》2013,8(10)
Neuroinflammation is involved in various central nervous system (CNS) disorders, including brain infections, ischemia, trauma, stroke, and degenerative CNS diseases. In the CNS inflammation, secretory phospholipase A2-IIA (sPLA2-IIA) acts as a mediator, resulting in the generation of the precursors of pro-inflammatory lipid mediators, such as prostaglandins (PGs) and leukotrienes (LTs). However, the role of sPLA2-IIA in neuroinflammation is more complicated and remains unclear yet. In the present study, we investigated the effect of sPLA2-IIA inhibition by specific inhibitor SC-215 on the inflammation in LPS-induced mice cerebral cortex and primary astrocytes. Our results showed that the inhibition of sPLA2-IIA alleviated the release of PGE2 by suppressing the activation of ERK1/2, cPLA2α, COX-2 and mPGES-1. These findings demonstrated that sPLA2-IIA showed the potential to regulate the neuroinflammation in vivo and in vitro, indicating that sPLA2-IIA might be a novel target for the treatment of acute neuroinflammation. 相似文献
6.
Qu XW Liu WP Qi ZY Duan ZJ Zheng LS Kuang ZZ Zhang WJ Hou YD 《Biochemical and biophysical research communications》2008,365(1):158-163
Human bocavirus (HBoV) is a new parvovirus first discovered in 2005, which is associated with acute respiratory infection. Analysis of sequence homology has revealed that a putative phospholipase A2 (PLA2) motif exists in the VP1 unique region of HBoV. However, little is known about whether the VP1 unique region of HBoV has PLA2 enzymatic activity and how these critical residues contribute to its PLA2 activity. To address these issues, the VP1 unique region protein and four of its mutants, were expressed in Eschericha coli. The purified VP1 unique protein (VP1U) showed a typical Ca2+-dependent secreted PLA2-like (sPLA2) activity, which was inhibited by sPLA2-specific inhibitors in a time-dependent manner. Mutation of one of the amino acids (21Pro, 41His, 42Asp or 63Asp) in VP1U almost eliminated the sPLA2 activity of HBoV VP1U. These data indicate that VP1U of HBoV has sPLA2-like enzymatic activity, and these residues are crucial for its sPLA2-like activity. Potentially, VP1U may be a target for the development of anti-viral drugs for HBoV. 相似文献
7.
Eleana Hatzidaki George Nakos Eftychia Galiatsou Marilena E. Lekka 《生物化学与生物物理学报:疾病的分子基础》2010,1802(11):986-994
The aim of this study was to investigate whether early phase of acute respiratory distress syndrome (ARDS) is associated with changes in immune response, either systemic or localized to the lung. ARDS and control mechanically ventilated patients, as well as healthy volunteers were studied. Alveolar macrophages (AMΦ) and blood monocytes (BM) were treated ex vivo with lipopolysaccharide (LPS), interferon-γ (IFNγ), and surfactant. Phospholipase A2 (PLA2) activity and TLR4 expression were evaluated as markers of cell response. AMΦ from ARDS patients did not respond upon treatment with either LPS or IFN-γ by inducing PLA2 production. On the contrary, upon stimulation, in control patients the intracellular PLA2, (mainly cPLA2) levels were increased, but secretion of PLA2 (mainly sPLA2-IIA) was observed only after treatment with LPS. Surfactant suppressed PLA2 production in cells from both groups of patients. Increased relative changes of total PLA2 activity and an upregulation of TLR4 expression upon stimulation was observed in BM from primary ARDS, control patients and healthy volunteers. In BM from secondary ARDS patients, however, no PLA2 induction was observed, with a concomitant down-regulation of TLR4 expression. Cytosolic PLA2, its activated form, p-cPLA2, and sPLA2-IIA were the predominant PLA2 types within the cells, while extracellularly only sPLA2-IIA was identified. These results support the concept of down-regulated innate immunity in early ARDS that is compartmentalized in primary and systemic in secondary ARDS. PLA2 isoforms could serve as markers of the immunity status in ARDS. Finally, our data highlight the role of surfactant in controlling inflammation. 相似文献
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Sun GY Xu J Jensen MD Yu S Wood WG González FA Simonyi A Sun AY Weisman GA 《Molecular neurobiology》2005,31(1-3):27-41
Astrocytes comprise the major cell type in the central nervous system (CNS) and they are essential for support of neuronal
functions by providing nutrients and regulating cell-to-cell communication. Astrocytes also are immune-like cells that become
reactive in response to neuronal injury. Phospholipases A2 (PLA
2) are a family of ubiquitous enzymes that degrade membrane phospholipids and produce lipid mediators for regulating cellular
functions. Three major classes of PLA
2 are expressed in astrocytes: group IV calcium-dependent cytosolic PLA
2 (cPLA2), group VI calcium-independent PLA
2 (iPLA2), and group II secretory PLA
2 (sPLA2). Upregulation of PLA
2 in reactive astrocytes has been shown to occur in a number of neurodegenerative diseases, including stroke and Alzheimer’s
disease. This review focuses on describing the effects of oxidative stress, inflammation, and activation of G protein-coupled
receptors on PLA
2 activation, arachidonic acid (AA) release, and production of prostanoids in astrocytes. 相似文献
10.
Makoto Murakami Hiroyasu Sato Yoshimi Miki Kei Yamamoto Yoshitaka Taketomi 《Journal of lipid research》2015,56(7):1248-1261
Among more than 30 members of the phospholipase A2 (PLA2) superfamily, secreted PLA2 (sPLA2) enzymes represent the largest family, being Ca2+-dependent low-molecular-weight enzymes with a His-Asp catalytic dyad. Individual sPLA2s exhibit unique tissue and cellular distributions and enzymatic properties, suggesting their distinct biological roles. Recent studies using transgenic and knockout mice for nearly a full set of sPLA2 subtypes, in combination with sophisticated lipidomics as well as biochemical and cell biological studies, have revealed distinct contributions of individual sPLA2s to various pathophysiological events, including production of pro- and anti-inflammatory lipid mediators, regulation of membrane remodeling, degradation of foreign phospholipids in microbes or food, or modification of extracellular noncellular lipid components. In this review, we highlight the current understanding of the in vivo functions of sPLA2s and the underlying lipid pathways as revealed by a series of studies over the last decade. 相似文献
11.
Yasunori Yokota Kohji Hanasaki Takashi Ono Hitoshi Nakazato Tatsuo Kobayashi Hitoshi Arita 《Biochimica et Biophysica Acta (BBA)/Molecular and Cell Biology of Lipids》1999,1438(2):213-222
Endotoxic shock is a systemic inflammatory process, involving a variety of proinflammatory mediators. Two types of secretory phospholipase A2 (sPLA2) have been implicated in this process. Group IB sPLA2 (PLA2-IB) binds to the PLA2 receptor (PLA2R), and PLA2R-deficient mice exhibit resistance to endotoxin-induced lethality with reduced plasma levels of proinflammatory cytokines, such as TNF-α. Group IIA sPLA2 (PLA2-IIA) is found in many tissues and cell types, and local and systemic levels are elevated under numerous inflammatory conditions including sepsis. In this study, we investigated the effect of a specific sPLA2 inhibitor, indoxam, on murine endotoxic shock. Indoxam suppressed the elevation of plasma TNF-α with a similar potency in PLA2-IIA-expressing and PLA2-IIA-deficient mice after LPS challenge. In PLA2-IIA-deficient mice, indoxam also suppressed the elevation of plasma IL-1β, IL-6 and NO, and prolonged survival after LPS challenge. Indoxam was found to block the PLA2-IB binding to murine PLA2R with a high potency (Ki=30 nM). The inhibitory effects of indoxam on the LPS-induced elevation of plasma TNF-α levels could not be observed in mice deficient in PLA2R. These findings suggest that indoxam blocks the production of proinflammatory cytokines during endotoxemia through PLA2-IIA-independent mechanisms, possibly via blockade of the PLA2R function. 相似文献
12.
In the acute phase of the inflammatory response, secretory phospholipase A2 (sPLA2) reaches its maximum levels in plasma, where it is mostly associated with high density lipoproteins (HDL). Overexpression of human sPLA2 in transgenic mice reduces both HDL cholesterol and apolipoprotein A-I (apoA-I) plasma levels through increased HDL catabolism by an unknown mechanism. To identify unknown PLA2-mediated activities on the molecular components of HDL, we characterized the protein and lipid products of the PLA2 reaction with HDL. Consistent with previous studies, hydrolysis of HDL phospholipids by PLA2 reduced the particle size without changing its protein composition. However, when HDL was destabilized in the presence of PLA2 by the action of cholesteryl ester transfer protein or by guanidine hydrochloride treatment, a fraction of apoA-I, but no other proteins, dissociated from the particle and was rapidly cleaved. Incubation of PLA2 with lipid-free apoA-I produced similar protein fragments in the range of 6–15 kDa, suggesting specific and direct reaction of PLA2 with apoA-I. Mass spectrometry analysis of isolated proteolytic fragments indicated at least two major cleavage sites at the C-terminal and the central domain of apoA-I. ApoA-I proteolysis by PLA2 was Ca2+-independent, implicating a different mechanism from the Ca2+-dependent PLA2-mediated phospholipid hydrolysis. Inhibition of proteolysis by benzamidine suggests that the proteolytic and lipolytic activities of PLA2 proceed through different mechanisms. Our study identifies a previously unknown proteolytic activity of PLA2 that is specific to apoA-I and may contribute to the enhanced catabolism of apoA-I in inflammation and atherosclerosis. 相似文献
13.
Murakami M Taketomi Y Miki Y Sato H Hirabayashi T Yamamoto K 《Progress in lipid research》2011,50(2):152-192
Mammalian genomes encode genes for more than 30 phospholipase A2s (PLA2s) or related enzymes, which are subdivided into several classes including low-molecular-weight secreted PLA2s (sPLA2s), Ca2+-dependent cytosolic PLA2s (cPLA2s), Ca2+-independent PLA2s (iPLA2s), platelet-activating factor acetylhydrolases (PAF-AHs), lysosomal PLA2s, and a recently identified adipose-specific PLA. Of these, the intracellular cPLA2 and iPLA2 families and the extracellular sPLA2 family are recognized as the “big three”. From a general viewpoint, cPLA2α (the prototypic cPLA2) plays a major role in the initiation of arachidonic acid metabolism, the iPLA2 family contributes to membrane homeostasis and energy metabolism, and the sPLA2 family affects various biological events by modulating the extracellular phospholipid milieus. The cPLA2 family evolved along with eicosanoid receptors when vertebrates first appeared, whereas the diverse branching of the iPLA2 and sPLA2 families during earlier eukaryote development suggests that they play fundamental roles in life-related processes. During the past decade, data concerning the unexplored roles of various PLA2 enzymes in pathophysiology have emerged on the basis of studies using knockout and transgenic mice, the use of specific inhibitors, and information obtained from analysis of human diseases caused by mutations in PLA2 genes. This review focuses on current understanding of the emerging biological functions of PLA2s and related enzymes. 相似文献
14.
Yona Goldshmit Kathryn Munro Soo Yuen Leong Alice Pébay Ann M. Turnley 《Cell and tissue research》2010,341(1):23-32
Lysophosphatidic acid (LPA) is released from platelets following injury and also plays a role in neural development but little is known about its effects in the adult central nervous system (CNS). We have examined the expression of LPA receptors 1-3 (LPA1–3) in intact mouse spinal cord and cortical tissues and following injury. In intact and injured tissues, LPA1 was expressed by ependymal cells in the central canal of the spinal cord and was upregulated in reactive astrocytes following spinal cord injury. LPA2 showed low expression in intact CNS tissue, on grey matter astrocytes in spinal cord and in ependymal cells lining the lateral ventricle. Following injury, its expression was upregulated on astrocytes in both cortex and spinal cord. LPA3 showed low expression in intact CNS tissue, viz. on cortical neurons and motor neurons in the spinal cord, and was upregulated on neurons in both regions after injury. Therefore, LPA1–3 are differentially expressed in the CNS and their expression is upregulated in response to injury. LPA release following CNS injury may have different consequences for each cell type because of this differential expression in the adult nervous system. 相似文献
15.
Yang Yang Junhua Liu Huihua Mao Yu-An Hu Yan Yan Chunjie Zhao 《Gene expression patterns : GEP》2009,9(7):532-540
Follistatin-like 1 (Fstl1), also named TSC-36 (TGF-β-stimulated clone 36), was first cloned from the mouse osteoblastic MC3T3-E1 cell line and can be up-regulated by TGF-β. To better study the function of Fstl1 during the development of the mouse central nervous system (CNS), we examined Fstl1 expression in the developing mouse CNS, in detail, by in situ hybridization. Our results show that Fstl1 is strongly expressed in the telencephalon, diencephalon, brainstem, limbic system and spinal cord. In the telencephalon, Fstl1 positive cells are mainly located in the ventricular zone (VZ) and the subventricular zone (SVZ); a relatively weak signal was observed in layers II and III of the neocortex at postnatal stages. Fstl1 expression is robust in the developing hippocampus and persists to P20. In the developing diencephalon and hindbrain, abundant Fstl1 signals were also detected in nuclei including the medial habenular nucleus, the medial dorsal nucleus, the cochlear nuclei and so on. In addition, a strong expression of Fstl1 was detected in the thalamencephalic signal center, as well as in the olfactory cortex from E14.5 to P0. Meanwhile, Fstl1 was expressed in the septal area and the cingulate gyrus of the limbic system after birth. A high level of expression was also observed in the ventral horn of the spinal cord. These results indicate that Fstl1 may play an important role during CNS development in the mouse. 相似文献
16.
An entomopathogenic bacterium, Xenorhabdus nematophila, induces an immunosuppression of target insects by inhibiting phospholipase A2 (PLA2) activity. Recently, an immune-associated PLA2 gene was identified from the red flour beetle, Tribolium castaneum. This study cloned this PLA2 gene in a bacterial expression vector to produce a recombinant enzyme. The recombinant T. castaneum PLA2 (TcPLA2) exhibited its characteristic enzyme activity with substrate concentration, pH, and ambient temperature. Its biochemical
characteristics matched to a secretory type of PLA2 (sPLA2) because its activity was inhibited by dithiothreitol (a reducing agent of disulfide bond) and bromophenacyl bromide (a specific
sPLA2 inhibitor) but not by methylarachidonyl fluorophosphonate (a specific cytosolic type of PLA2). The X. nematophila culture broth contained PLA2 inhibitory factor(s), which was most abundant in the media obtained at a stationary bacterial growth phase. The PLA2 inhibitory factor(s) was heat-resistant and extracted in both aqueous and organic fractions. Effect of a PLA2-inhibitory fraction on the immunosuppression of T. castaneum was equally comparable with that resulted from inhibition of the TcPLA2 gene expression by RNA interference. 相似文献
17.
Brain platelet‐activating factor (PAF) is a lipid mediator involved in neurotransmission and in LTP. It has been reported that the induction of LTP by high frequency stimulation increases the activity of the enzymes responsible for its synthesis by a still unknown mechanism ( 1 ). One of the two biosynthetic pathways is Ca2+‐dependent and transforms a membrane ether phospholipid into PAF by a sequence of two reactions being the first one, catalyzed by a phospholipase A2 (PLA2), rate limiting. Overproduction of PAF, taking place in pathological conditions, contributes to brain damage. Various PLA2s are present in brain tissue and, particularly, sPLA2‐IIA is very likely involved in the production of PAF as its expression increases in pathological conditions. Recently, we have found the release of sPLA2‐IIA from rat brain cortex mitochondria and its association with nuclear membranes, which might be an intracellular target for the enzyme. 相似文献
18.
《Biochimica et Biophysica Acta (BBA)/Molecular and Cell Biology of Lipids》2019,1864(6):803-818
Among the 11 members of the secreted phospholipase A2 (sPLA2) family, group IID, IIE, IIF and III sPLA2s (sPLA2-IID, -IIE, -IIF and -III, respectively) are “new” isoforms in the history of sPLA2 research. Relative to the better characterized sPLA2s (sPLA2-IB, -IIA, -V and -X), the enzymatic properties, distributions, and functions of these “new” sPLA2s have remained obscure until recently. Our current studies using knockout and transgenic mice for a nearly full set of sPLA2s, in combination with comprehensive lipidomics, have revealed unique and distinct roles of these “new” sPLA2s in specific biological events. Thus, sPLA2-IID is involved in immune suppression, sPLA2-IIE in metabolic regulation and hair follicle homeostasis, sPLA2-IIF in epidermal hyperplasia, and sPLA2-III in male reproduction, anaphylaxis, colonic diseases, and possibly atherosclerosis. In this article, we overview current understanding of the properties and functions of these sPLA2s and their underlying lipid pathways in vivo. 相似文献
19.
Cardiolipin, a major component of mitochondria, is critical for mitochondrial functioning including the regulation of cytochrome c release during apoptosis and proper electron transport. Mitochondrial cardiolipin with its unique bulky amphipathic structure is a potential substrate for phospholipase A2 (PLA2) in vivo. We have developed mass spectrometric methodology for analyzing PLA2 activity toward various cardiolipin forms and demonstrate that cardiolipin is a substrate for sPLA2, cPLA2 and iPLA2, but not for Lp-PLA2. Our results also show that none of these PLA2s have significant PLA1 activities toward dilyso-cardiolipin. To understand the mechanism of cardiolipin hydrolysis by PLA2, we also quantified the release of monolyso-cardiolipin and dilyso-cardiolipin in the PLA2 assays. The sPLA2s caused an accumulation of dilyso-cardiolipin, in contrast to iPLA2 which caused an accumulation of monolyso-cardiolipin. Moreover, cardiolipin inhibits iPLA2 and cPLA2, and activates sPLA2 at low mol fractions in mixed micelles of Triton X-100 with the substrate 1-palmitoyl-2-arachidonyl-sn-phosphtidylcholine. Thus, cardiolipin functions as both a substrate and a regulator of PLA2 activity and the ability to assay the various forms of PLA2 is important in understanding its function. 相似文献
20.
We propose that expression of four genes encoding secretory phospholipases A2 (sPLA2) mediates insect nodulation responses to bacterial infection. Nodulation is the quantitatively predominant cellular defense reaction to bacterial infection. This reaction is mediated by eicosanoids, the biosynthesis of which depends on PLA2-catalyzed hydrolysis of arachidonic acid (AA) from cellular phospholipids. Injecting late instar larvae of the red flour beetle, Tribolium castaneum, with the bacterium, Escherichia coli, stimulated nodulation reactions and sPLA2 activity in time- and dose-related manners. Nodulation was inhibited by pharmaceutical inhibitors of enzymes involved in eicosanoid biosynthesis, and the inhibition was rescued by AA. We cloned five genes encoding sPLA2 and expressed them in E. coli cells to demonstrate these genes encode catalytically active sPLA2s. The recombinant sPLA2s were inhibited by sPLA2 inhibitors. Injecting larvae with double-stranded RNAs specific to each of the five genes led to reduced expression of the corresponding sPLA2 genes and to reduced nodulation reactions to bacterial infections for four of the five genes. The reduced nodulation was rescued by AA, indicating that expression of four genes encoding sPLA2s mediates nodulation reactions. A polyclonal antibody that reacted with all five sPLA2s showed the presence of the sPLA2 enzymes in hemocytes and revealed that the enzymes were more closely associated with hemocyte plasma membranes following infection. Identifying specific sPLA2 genes that mediate nodulation reactions strongly supports our hypothesis that sPLA2s are central enzymes in insect cellular immune reactions. 相似文献