scholarly journals Interconnection of phospholipolysis and monooxygenase catalysis

2021 ◽  
Vol 57 (4) ◽  
pp. 488-501
Author(s):  
N. M. Litvinko
Keyword(s):  
Arachidonic Acid ◽  
Phospholipase A2 ◽  
Cytochromes P450 ◽  
Signal Transmission ◽  
Experimental Results ◽  
External Signal ◽  
Enzyme Systems ◽  
Intracellular Messengers

A review of the main experimental results in the field of studying the interaction in vivo and in vitro of enzyme systems responsible for the metabolism of arachidonic acid is presented. Metabolic events from its release from phospholipids (phospholipase A2) to its transformation (cytochromes P450) into the most important intracellular messengers of external signal transmission to the internal “language of the cell” are discussed.

Transcriptomic profiling of phospholipase A2 and the role of arachidonic acid during Brucella abortus 544 infection in both in vitro and in vivo systems

2020 ◽  
pp. 104655
Author(s):  
Son Hai Vu ◽  
Alisha Wehdnesday Bernardo Reyes ◽  
Tran Xuan Ngoc Huy ◽  
Wongi Min ◽  
Hu Jang Lee ◽  
...  
Keyword(s):  
Arachidonic Acid ◽  
Phospholipase A2 ◽  
Brucella Abortus ◽  
Transcriptomic Profiling

scholarly journals An ARF GTPase module promoting invasion and metastasis through regulating phosphoinositide metabolism

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Marisa Nacke ◽  
Emma Sandilands ◽  
Konstantina Nikolatou ◽  
Álvaro Román-Fernández ◽  
Susan Mason ◽  
...  
Keyword(s):  
Metastatic Cancer ◽  
Cellular Responses ◽  
Signalling Pathways ◽  
External Signal ◽  
Phosphoinositide Metabolism ◽  
Invasion And Metastasis ◽  
3 Dimensional

AbstractThe signalling pathways underpinning cell growth and invasion use overlapping components, yet how mutually exclusive cellular responses occur is unclear. Here, we report development of 3-Dimensional culture analyses to separately quantify growth and invasion. We identify that alternate variants of IQSEC1, an ARF GTPase Exchange Factor, act as switches to promote invasion over growth by controlling phosphoinositide metabolism. All IQSEC1 variants activate ARF5- and ARF6-dependent PIP5-kinase to promote PI(3,4,5)P3-AKT signalling and growth. In contrast, select pro-invasive IQSEC1 variants promote PI(3,4,5)P3 production to form invasion-driving protrusions. Inhibition of IQSEC1 attenuates invasion in vitro and metastasis in vivo. Induction of pro-invasive IQSEC1 variants and elevated IQSEC1 expression occurs in a number of tumour types and is associated with higher-grade metastatic cancer, activation of PI(3,4,5)P3 signalling, and predicts long-term poor outcome across multiple cancers. IQSEC1-regulated phosphoinositide metabolism therefore is a switch to induce invasion over growth in response to the same external signal. Targeting IQSEC1 as the central regulator of this switch may represent a therapeutic vulnerability to stop metastasis.

scholarly journals Group V Phospholipase A2 Mediates Endothelial Dysfunction and Acute Lung Injury Caused by Methicillin-Resistant Staphylococcus aureus

Cells ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1731
Author(s):  
Yu Maw Htwe ◽  
Huashan Wang ◽  
Patrick Belvitch ◽  
Lucille Meliton ◽  
Mounica Bandela ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Acute Lung Injury ◽  
Endothelial Dysfunction ◽  
Lung Injury ◽  
Phospholipase A2 ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Group V ◽  
Methicillin Resistant

Lung endothelial dysfunction is a key feature of acute lung injury (ALI) and clinical acute respiratory distress syndrome (ARDS). Previous studies have identified the lipid-generating enzyme, group V phospholipase A2 (gVPLA2), as a mediator of lung endothelial barrier disruption and inflammation. The current study aimed to determine the role of gVPLA2 in mediating lung endothelial responses to methicillin-resistant Staphylococcus aureus (MRSA, USA300 strain), a major cause of ALI/ARDS. In vitro studies assessed the effects of gVPLA2 inhibition on lung endothelial cell (EC) permeability after exposure to heat-killed (HK) MRSA. In vivo studies assessed the effects of intratracheal live or HK-MRSA on multiple indices of ALI in wild-type (WT) and gVPLA2-deficient (KO) mice. In vitro, HK-MRSA increased gVPLA2 expression and permeability in human lung EC. Inhibition of gVPLA2 with either the PLA2 inhibitor, LY311727, or with a specific monoclonal antibody, attenuated the barrier disruption caused by HK-MRSA. LY311727 also reduced HK-MRSA-induced permeability in mouse lung EC isolated from WT but not gVPLA2-KO mice. In vivo, live MRSA caused significantly less ALI in gVPLA2 KO mice compared to WT, findings confirmed by intravital microscopy assessment in HK-MRSA-treated mice. After targeted delivery of gVPLA2 plasmid to lung endothelium using ACE antibody-conjugated liposomes, MRSA-induced ALI was significantly increased in gVPLA2-KO mice, indicating that lung endothelial expression of gVPLA2 is critical in vivo. In summary, these results demonstrate an important role for gVPLA2 in mediating MRSA-induced lung EC permeability and ALI. Thus, gVPLA2 may represent a novel therapeutic target in ALI/ARDS caused by bacterial infection.

scholarly journals A Biochemical and Pharmacological Characterization of Phospholipase A2 and Metalloproteinase Fractions from Eastern Russell’s Viper (Daboia siamensis) Venom: Two Major Components Associated with Acute Kidney Injury

Toxins ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 521
Author(s):  
Janeyuth Chaisakul ◽  
Orawan Khow ◽  
Kulachet Wiwatwarayos ◽  
Muhamad Rusdi Ahmad Rusmili ◽  
Watcharamon Prasert ◽  
...  
Keyword(s):  
Acute Kidney Injury ◽  
Phospholipase A2 ◽  
Protein Identification ◽  
Clinical Manifestations ◽  
Kidney Injury ◽  
Factor X ◽  
Pharmacological Characterization ◽  
Russell’S Viper

Acute kidney injury (AKI) following Eastern Russell’s viper (Daboia siamensis) envenoming is a significant symptom in systemically envenomed victims. A number of venom components have been identified as causing the nephrotoxicity which leads to AKI. However, the precise mechanism of nephrotoxicity caused by these toxins is still unclear. In the present study, we purified two proteins from D. siamensis venom, namely RvPLA2 and RvMP. Protein identification using LCMS/MS confirmed the identity of RvPLA2 to be snake venom phospholipase A2 (SVPLA2) from Thai D. siamensis venom, whereas RvMP exhibited the presence of a factor X activator with two subunits. In vitro and in vivo pharmacological studies demonstrated myotoxicity and histopathological changes of kidney, heart, and spleen. RvPLA2 (3–10 µg/mL) caused inhibition of direct twitches of the chick biventer cervicis muscle preparation. After administration of RvPLA2 or RvMP (300 µg/kg, i.p.) for 24 h, diffuse glomerular congestion and tubular injury with minor loss of brush border were detected in envenomed mice. RvPLA2 and RvMP (300 µg/kg; i.p.) also induced congestion and tissue inflammation of heart muscle as well as diffuse congestion of mouse spleen. This study showed the significant roles of PLA2 and SVMP in snake bite envenoming caused by Thai D. siamensis and their similarities with observed clinical manifestations in envenomed victims. This study also indicated that there is a need to reevaluate the current treatment strategies for Thai D. siamensis envenoming, given the potential for irreversible nephrotoxicity.

scholarly journals Monoclonal antibodies specific to a Ca2+-bound form of lipocortin I distinguish its Ca2+-dependent phospholipid-binding ability from its ability to inhibit phospholipase A2

1990 ◽  
Vol 269 (3) ◽  
pp. 709-715 ◽  
Author(s):  
H Hayashi ◽  
M K Owada ◽  
S Sonobe ◽  
K Domae ◽  
T Yamanouchi ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Phospholipase A2 ◽  
Inhibitory Activity ◽  
Biological Effects ◽  
Free Form ◽  
E Coli ◽  
Phospholipid Binding ◽  
Ef Hand

Lipocortin I, a Ca2(+)-and phospholipid-binding protein without EF-hand structures, has many biological effects in vitro. Its actual role in vivo, however is unknown. We obtained and characterized five monoclonal antibodies to lipocortin I. Two of these monoclonal antibodies (L2 and L4-MAbs) reacted with the Ca(+)-bound form of lipocortin I, but not with the Ca2(+)-free form, both in vivo and in vitro. Lipocortin I required greater than or equal to 10 microM-Ca2+ to bind the two antibodies, and this Ca2+ requirement was not affected by phosphatidylserine. L2-MAb abolished the phospholipase A2 inhibitory activity of lipocortin I and inhibited its binding to Escherichia coli membranes and to phosphatidylserine in vitro. L4-MAb abolished the phospholipase A2 inhibitory activity of lipocortin I, but did not affect its binding to E. coli membranes or to phosphatidylserine. These findings indicated that the inhibition of phospholipase A2 by lipocortin I was not simply due to removal or capping of the substrates in E. coli membranes. Furthermore, an immunofluorescence study using L2-MAb showed the actual existence of Ca2(+)-bound form of lipocortin I in vivo.

P-450 Metabolites of Arachidonic Acid in the Control of Cardiovascular Function

2002 ◽  
Vol 82 (1) ◽  
pp. 131-185 ◽  
Author(s):  
Richard J. Roman
Keyword(s):  
Arachidonic Acid ◽  
Angiotensin Ii ◽  
Vascular Tone ◽  
Mesangial Cells ◽  
Cardiovascular Function ◽  
Tubuloglomerular Feedback ◽  
Peripheral Vasculature ◽  
Therapeutic Benefits

Recent studies have indicated that arachidonic acid is primarily metabolized by cytochrome P-450 (CYP) enzymes in the brain, lung, kidney, and peripheral vasculature to 20-hydroxyeicosatetraenoic acid (20-HETE) and epoxyeicosatrienoic acids (EETs) and that these compounds play critical roles in the regulation of renal, pulmonary, and cardiac function and vascular tone. EETs are endothelium-derived vasodilators that hyperpolarize vascular smooth muscle (VSM) cells by activating K+channels. 20-HETE is a vasoconstrictor produced in VSM cells that reduces the open-state probability of Ca2+-activated K+channels. Inhibitors of the formation of 20-HETE block the myogenic response of renal, cerebral, and skeletal muscle arterioles in vitro and autoregulation of renal and cerebral blood flow in vivo. They also block tubuloglomerular feedback responses in vivo and the vasoconstrictor response to elevations in tissue Po2both in vivo and in vitro. The formation of 20-HETE in VSM is stimulated by angiotensin II and endothelin and is inhibited by nitric oxide (NO) and carbon monoxide (CO). Blockade of the formation of 20-HETE attenuates the vascular responses to angiotensin II, endothelin, norepinephrine, NO, and CO. In the kidney, EETs and 20-HETE are produced in the proximal tubule and the thick ascending loop of Henle. They regulate Na+transport in these nephron segments. 20-HETE also contributes to the mitogenic effects of a variety of growth factors in VSM, renal epithelial, and mesangial cells. The production of EETs and 20-HETE is altered in experimental and genetic models of hypertension, diabetes, uremia, toxemia of pregnancy, and hepatorenal syndrome. Given the importance of this pathway in the control of cardiovascular function, it is likely that CYP metabolites of arachidonic acid contribute to the changes in renal function and vascular tone associated with some of these conditions and that drugs that modify the formation and/or actions of EETs and 20-HETE may have therapeutic benefits.

scholarly journals Integrated experimental-computational analysis of a liver-islet microphysiological system for human-centric diabetes research

2021 ◽  
Author(s):  
Belén Casas ◽  
Liisa Vilén ◽  
Sophie Bauer ◽  
Kajsa Kanebratt ◽  
Charlotte Wennberg Huldt ◽  
...  
Keyword(s):  
Glucose Metabolism ◽  
Computational Model ◽  
In Silico ◽  
Experimental Results ◽  
Published Data ◽  
Diabetes Research ◽  
Glucose Response ◽  
High Blood Glucose

Microphysiological systems (MPS) are powerful tools for emulating human physiology and replicating disease progression in vitro. MPS could be better predictors of human outcome than current animal models, but mechanistic interpretation and in vivo extrapolation of the experimental results remain significant challenges. Here, we address these challenges using an integrated experimental-computational approach. This approach allows for in silico representation and predictions of glucose metabolism in a previously reported MPS with two organ compartments (liver and pancreas) connected in a closed loop with circulating medium. We developed a computational model describing glucose metabolism over 15 days of culture in the MPS. The model was calibrated on an experiment-specific basis using data from seven experiments, where single-liver or liver-islet cultures were exposed to both normal and hyperglycemic conditions resembling high blood glucose levels in diabetes. The calibrated models reproduced the fast (i.e. hourly) variations in glucose and insulin observed in the MPS experiments, as well as the long-term (i.e. over weeks) decline in both glucose tolerance and insulin secretion. We also investigated the behavior of the system under hypoglycemia by simulating this condition in silico, and the model could correctly predict the glucose and insulin responses measured in new MPS experiments. Last, we used the computational model to translate the experimental results to humans, showing good agreement with published data of the glucose response to a meal in healthy subjects. The integrated experimental-computational framework opens new avenues for future investigations toward disease mechanisms and the development of new therapies for metabolic disorders.

Contributions of arachidonic acid derivatives and substance P to the sensitization of cutaneous nociceptors

1990 ◽  
Vol 64 (2) ◽  
pp. 457-464 ◽  
Author(s):  
R. H. Cohen ◽  
E. R. Perl
Keyword(s):  
Arachidonic Acid ◽  
Substance P ◽  
Receptive Fields ◽  
Lipoxygenase Inhibitor ◽  
Arterial Perfusion ◽  
Mediators Of Inflammation ◽  
Rabbit Ear ◽  
C Fiber

1. The role of presumed chemical mediators of inflammation in the heat-induced sensitization of cutaneous C-polymodal nociceptors (CPNs) was examined in a rabbit ear preparation maintained in vitro by intra-arterial perfusion with a solution free of protein and cellular elements. 2. In this preparation, CPNs consistently showed enhanced responsiveness after repeated exposure of their receptive fields to noxious levels of heat. The average magnitude of sensitization was quantitatively similar to that observed in vivo, suggesting that blood-born factors are not essential for development of sensitization. 3. Sensitization in one-half of randomly selected CPNs was blocked or reduced when the perfusate contained a cyclooxygenase inhibitor, indomethacin or dipyrone, or the dual cyclooxygenase/lipoxygenase inhibitor, BW755C, even though initial responsiveness to heat and pressure was unaltered. These observations suggest that arachidonic acid breakdown products, possibly prostaglandins, are intermediaries in the sensitization of some, but not all, C-fiber nociceptors of the skin. In addition, heat-induced sensitization for some C-fiber cutaneous nociceptors is the result of processes that are at least partially independent of those involved in excitation. 4. Substance P (SP) or the putative SP antagonists, [D-Pro2, D-Trp7.9]-SP or [D-Pro2, D-Phe7, D-Trip9]-SP, produced no significant effect on heat-responsiveness or sensitization, although ongoing activity may have marginally increased over control levels after repeated heat stimulations. We conclude that SP in an in vitro preparation is not involved in the enhancement of cutaneous C-fiber nociceptor responsiveness after repeated thermal insults.

Sign in / Sign up

Export Citation Format

Share Document