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Role of Vasoactive Intestinal Peptide in Myocardial Ischemia Reperfusion Injury
Published in Sami I. Said, Proinflammatory and Antiinflammatory Peptides, 2020
Dipak K. Das, Nilanjana Maulik, Richard M. Engelman
Recently, phospholipase D has been found to be involved in the intracellular signaling in ischemic heart (71). Phospholipase D signaling, like the phenomenon of phospholipase C signaling, also occurs in the ischemic heart; but unlike phospholipase C signaling, phospholipase D signaling is actually beneficial to the ischemic heart. The results of this study also suggested that the activation of phospholipase D contributes significantly to the formation of DG, because phospholipase D-produced phosphatidic acid is dephosphorylated by phosphatidate phosphatase into DG (whereas phospholipase C activation produces DG directly). It seems likely that phosphatidic acid functions as a second messenger either indirectly, through generation of DG and subsequent protein kinase C activity, or directly, through an as yet unknown mechanism (as suggested also by recent studies in neutrophils and other cell types). If this is true (this possibility has never been explored), many unanswered questions may be resolved.
The Airway and Vasoactive Intestinal Peptide Autoantibodies and Receptors
Published in Devendra K. Agrawal, Robert G. Townley, Inflammatory Cells and Mediators in Bronchial Asthma, 2020
In their natural milieu, receptors interact intimately with phospholipids. Treatment with phospholipases A2 or C, but not phospholipase D, resulted in decreased VIP binding by the 5.9-nm SR complex.19 Phospholipid head-group removal may destabilize subunit interactions and dissociate the complex, accompanied by decreased VIP-binding affinity. In contrast, binding by the 2.3-nm SR receptor was enhanced (p <0.01) by phospholipase A2 or C pretreatment. This increase in VIP binding was Ca2+ dependent. Scatchard analysis revealed that phospholipase C treatment increased the receptor number, perhaps reflecting a receptor unmasking effect.
Regulation of the Arachidonic Acid Cascade and PAF Metabolism in Reproductive Tissues
Published in Murray D. Mitchell, Eicosanoids in Reproduction, 2020
John M. Johnston, Noriei Maki, Marlane J. Angle, Dennis R. Hoffman
Glycerophospholipid degradation in mammalian tissue is primarily catalyzed by the action of phospholipases, as illustrated in Figure 2. With the exception of phosphatidylinositol, most glycerophospholipids are degraded via phospholipase A enzymes. The phosphatidylinositol pathway employs phospholipase C; the products of this reaction are inositol phosphate(s) and diacylglycerol. The role of the inositol polyphosphates and diacylglycerol as second messengers and the relationship of Ca2+ to signal transduction and protein kinase C activity have recently been reviewed.31,32 More recently, a role for phospholipase D, which has been purified from mammalian tissues,33 has been implicated in the generation of phosphatidic acid, which may subsequently function as a second messenger.34
PLD1 knockdown reduces metastasis and inflammation of fibroblast-like synoviocytes in rheumatoid arthritis by modulating NF-κB and Wnt/β-catenin pathways
Published in Autoimmunity, 2021
Zhengyu Zhang, Xi Chen, Bo Gao, Guomin Sun, Yan Wang, Junke Wang, Ting Zhang, Hao Qian, Yu Zhang, Jun Huang, Rurong Sun, Jiabiao Wu, Lei Zhou
Phospholipase D (PLD) is an enzyme that hydrolyses phosphodiester linkages in phosphatidylcholine (PC) [4]. PLD is divided into two subtypes, named PLD1 and PLD2 [6]. In mammals, PLD1 mainly acts in some signal transduction pathways, such as membrane transport, regulation of mitosis and cellular actin skeleton [7]. It is reported that PLD1 is able to regulate the proliferation, migration, and invasion of tumour cells [8,9]. Targeting PLD1 can ameliorate collagen-induced arthritis (CIA) by regulating the imbalance of Treg and Th17 cells, and thus inhibiting the development of osteoclasts [10]. In addition, PLD is associated with the activation of a variety of inflammatory mediators, which in turn affect the proliferation, division, and secretion of cell-specific protein kinases [4]. Therefore, the expression of PLD might be related with arthritis. However, the role of PLD1 in FLSs of RA remains unclear, which requires further investigations.
Expression and clinical significance of phospholipase D1 in de novo acute myeloid leukemia
Published in Hematology, 2020
Ying Lu, Jiasi Zhou, Renzhi Pei, Fenglin Li, Jie Jin, Lei Jiang
Phospholipase D (PLD) is a membrane protein that hydrolyzes phosphatidylcholine to phosphatidic acid and choline [3]. PLD1 and PLD2, two mammalian isoforms of PLD, have been proposed to play important roles in cancer. For instance, PLD1 is overexpressed in human breast cancer tissues and inhibition of either PLD1 or PLD2 enhances the sensitivity of breast cancer cells to radiotherapy [4,5]. Increased PLD expression or activity is also found in colorectal and prostate cancers, although the underlying mechanism remains unclear [6,7]. When wild-type melanoma and lung carcinoma cells are implanted in PLD1 deficiency mice, tumor growth, angiogenesis, and metastasis are impaired, indicating a critical role of PLD1 in tumor microenvironment [8]. However, a subset of chronic lymphocytic leukemia unresponsive to chemokine is characterized by defective activation of PLD1, suggesting that the function of PLD1 is not always pro-oncogenic [9,10].
Atypical systemic and dermatologic loxoscelism in a non-endemic region of the USA
Published in Clinical Toxicology, 2021
John W. Downs, Kevin T. Gould, Ryan C. Mclaughlin, Kirk L. Cumpston, S. Rutherfoord Rose
Sphingomyelinase-D was previously believed to be the primary venom component in brown spiders responsible for both the local dermatonecrotic reaction, as well as hemolysis [19]. However, more recent studies have implicated a group of isoforms of phospholipase D (PLD) toxins as responsible for both the local and systemic effects [20]. In LX, PLD induces erythrocyte lysis through an interaction with red cell metalloproteinases. In turn, the resulting hemolysis triggers a complement cascade leading to greater hemolysis [2,6]. Arguments in favor of the administration of systemic corticosteroids in SL have generally noted that corticosteroids may reduce the resulting complement cascade, thereby averting or reducing the severity of hemolysis.