Role of Membrane Phospholipids in Nonfreezing Cold Injury

1991 ◽  
pp. 245-257 ◽  
Author(s):  
Dipak K. Das ◽  
Swapna Maity ◽  
Dan Lu
Keyword(s):  
Cold Injury ◽  
Membrane Phospholipids

Role of phospholipases A2 and C in myocardial ischemic reperfusion injury

1991 ◽  
Vol 260 (3) ◽  
pp. H877-H883 ◽  
Author(s):  
M. R. Prasad ◽  
L. M. Popescu ◽  
I. I. Moraru ◽  
X. K. Liu ◽  
S. Maity ◽  
...  
Keyword(s):  
Immunoglobulin G ◽  
Ischemic Myocardium ◽  
Lower Amount ◽  
Cellular Injury ◽  
Membrane Phospholipids ◽  
Nonesterified Fatty Acids ◽  
Subcellular Organelles ◽  
Phospholipases A2 ◽  
Rat Hearts

We investigated the role of phospholipase A2 (PLA2) and phospholipase C (PLC) in myocardial phosholipid degradation and cellular injury during reperfusion of ischemic myocardium. For this purpose, isolated rat hearts were perfused with isotopic arachidonic acid to label its membrane phospholipids. Hearts preperfused with antiphospholipase A2 (anti-PLA2) retained a significantly higher amount of radiolabel in phosphatidylcholine and phosphatidylinositol and a corresponding lower amount of radiolabel in lysophosphatidylcholine and nonesterified fatty acids (P less than 0.05) after 30 min of reperfusion following 30 min of normothermic global ischemia compared with hearts preperfused with nonimmune immunoglobulin G. In similar experiments, antiphospholipase C (anti-PLC)-treated hearts were associated with significantly (P less than 0.05) higher radiolabel in all phospholipids and lower radiolabel in diacyglycerol compared with nonimmune immunoglobulin G-treated hearts. Measurement of phospholipase activity in subcellular organelles of these hearts showed decreased PLA2 activity in cytosol, mitochondria, and microsomes of anti-PLA2-treated hearts and decreased PLC activity of microsomes in anti-PLC-treated hearts. Furthermore, both the antiphospholipases attenuated the release of creatine kinase and lactate dehydrogenase into perfusate and increased contractility as well as coronary flow in the reperfused hearts. Results of this study suggest that both PLA2 and PLC are involved in the degradation of phospholipids and cellular injury that occur during reperfusion of ischemic myocardium.

Evolution of the diverse biological roles of inositols

2007 ◽  
Vol 74 ◽  
pp. 223-246 ◽  
Author(s):  
Robert H. Michell
Keyword(s):  
Membrane Trafficking ◽  
Cell Signalling ◽  
Compatible Solutes ◽  
Mirror Image ◽  
Membrane Phospholipids ◽  
Functional Diversification ◽  
Redox Reagent ◽  
Ca2 Channels ◽  
Mycobacterium Spp

Several of the nine hexahydroxycylohexanes (inositols) have functions in Biology, with myo-inositol (Ins) in most of the starring roles; and Ins polyphosphates are amongst the most abundant organic phosphate constituents on Earth. Many Archaea make Ins and use it as a component of diphytanyl membrane phospholipids and the thermoprotective solute di-L-Ins-1,1′-phosphate. Few bacteria make Ins or use it, other than as a carbon source. Those that do include hyperthermophilic Thermotogales (which also employ di-l-Ins-1,1′-phosphate) and actinomycetes such as Mycobacterium spp. (which use mycothiol, an inositol-containing thiol, as an intracellular redox reagent and have characteristic phosphatidylinositol-linked surface oligosaccharides). Bacteria acquired their Ins3P synthases by lateral gene transfer from Archaea. Many eukaryotes, including stressed plants, insects, deep-sea animals and kidney tubule cells, adapt to environmental variation by making or accumulating diverse inositol derivatives as ‘compatible’ solutes. Eukaryotes use phosphatidylinositol derivatives for numerous roles in cell signalling and regulation and in protein anchoring at the cell surface. Remarkably, the diradylglycerol cores of archaeal and eukaryote/bacterial glycerophospholipids have mirror image configurations: sn-2,3 and sn-1,2 respectively. Multicellular animals and amoebozoans exhibit the greatest variety of functions for PtdIns derivatives, including the use of PtdIns(3,4,5)P3 as a signal. Evolutionarily, it seems likely that (i) early archaeons first made myo-inositol approx. 3500 Ma (million years) ago; (ii) archeons brought inositol derivatives into early eukaryotes (approx. 2000 Ma?); (iii) soon thereafter, eukaryotes established ubiquitous functions for phosphoinositides in membrane trafficking and Ins polyphosphate synthesis; and (iv) since approx. 1000 Ma, further waves of functional diversification in amoebozoans and metazoans have introduced Ins(1,4,5)P3 receptor Ca2+ channels and the messenger role of PtdIns(3,4,5)P3.

Regulation Of The Fatty Acid Composition Of Platelet Phospholipids

1981 ◽  
Author(s):  
M L McKean ◽  
J B Smith ◽  
M J Silver
Keyword(s):  
Fatty Acids ◽  
Fatty Acid Composition ◽  
Fatty Acid ◽  
Acid Composition ◽  
Unsaturated Fatty Acids ◽  
De Novo ◽  
Membrane Phospholipids ◽  
De Novo Biosynthesis ◽  
Coa Transferase

The fatty acid composition of cell membrane phospholipids does not remain constant after de novo biosynthesis, but undergoes continual remodelling. One of the major routes for remodelling probably includes the deacylation-reacylation steps of the Lands Pathway. This has been shown to be important for the incorporation of long chain, polyunsaturated fatty acids into phospholipids by liver and brain. An understanding of the mechanisms involved in these processes in platelets is especially important in light of the large stores of arachidonic acid (AA) in platelet phospholipids and the role of AA in hemostasis and thrombosis. Previous results from this laboratory have shown that the turnover of radioactive AA, 8,11,14-eicosatrienoic and 5,8,11,14,17-eicosapentaenoic acids in the phospholipids of resting platelets is more rapid than the turnover of radioactive C16 and C18 saturated and unsaturated fatty acids. However, little is known about how fatty acids, especially AA and its homologues, are incorporated into platelet phospholipids during de novo biosynthesis or how they are exchanged during remodelling.At least three enzymes are involved in the deacylation- reacylation of phospholipids: phospholipase A2; acyl CoA synthetase; and acyl CoA transferase. We have studied acyl CoA transferase and have found considerable activity in human platelet membranes. Experiments are in progress to determine the substrate specificity and other properties of this enzyme.

scholarly journals Altered Metabolism of Phospholipases, Diacylglycerols, Endocannabinoids, and N-Acylethanolamines in Patients with Mastocytosis

2019 ◽  
Vol 2019 ◽  
pp. 1-14
Author(s):  
Anne Lise Ferrara ◽  
Fabiana Piscitelli ◽  
Angelica Petraroli ◽  
Roberta Parente ◽  
Maria Rosaria Galdiero ◽  
...  
Keyword(s):  
Mast Cells ◽  
Disease Severity ◽  
Plasma Levels ◽  
Second Messengers ◽  
Lipid Mediators ◽  
Healthy Individuals ◽  
Membrane Phospholipids ◽  
Altered Metabolism ◽  
Potential Biomarkers

Background. Mastocytosis is a condition characterized by the expansion and accumulation of mast cells (MCs) in various organs. The symptoms are related to the increased release of MC-derived mediators that exert local and distant effects. MCs are a source and target of phospholipase enzymes (PLs), which catalyze the cleavage of membrane phospholipids releasing lipid mediators (e.g., diacylglycerols (DAGs) and the endocannabinoid (EC) 2-arachidonoylglycerol (2-AG)). To date, there are no data on the role of these lipid mediators in mastocytosis. Here, we analyzed plasma levels of PLA2, PLC, DAG, ECs, and EC-related N-acylethanolamines in patients with mastocytosis. Methods. In 23 patients with mastocytosis and 23 healthy individuals, we measured plasma PLA2 and PLC activities, DAG, 2-AG, anandamide (AEA), palmitoylethanolamide (PEA), and oleoylethanolamide (OEA). Results. Plasma PLA2 and PLC activities were increased in mastocytosis patients compared to controls. Concentrations of DAG (18:1 20:4 and 18:0 20:4), two second messengers produced by PLC, were higher in mastocytosis compared to controls, whereas the concentrations of their metabolite, 2-AG, were not altered. AEA was decreased in mastocytosis patients compared to controls; by contrast, AEA congener, PEA, was increased. PLA2 and PLC activities were increased only in patients with mediator-related symptoms. Moreover, PLC activity was positively correlated with disease severity and tryptase concentrations. By contrast, AEA was negatively correlated with tryptase concentrations. Conclusions. PLs and some lipid mediators are altered in patients with mastocytosis. Our results may pave the way for investigating the functions of these mediators in the pathophysiology of mastocytosis and provide new potential biomarkers and therapeutic targets.

Organization and role of platelet membrane phospholipids as studied with purified phospholipases

1979 ◽  
Vol 9 (4) ◽  
pp. 400-406 ◽  
Author(s):  
H. Chap ◽  
B. Perret ◽  
G. Mauco ◽  
M. F. Simon ◽  
L. Douste-Blazy
Keyword(s):  
Platelet Membrane ◽  
Membrane Phospholipids

Nitric oxide-dependent pro-oxidant and pro-apoptotic effect of metallothioneins in HL-60 cells challenged with cupric nitrilotriacetate

2001 ◽  
Vol 354 (2) ◽  
pp. 397-406 ◽  
Author(s):  
Shang-Xi LIU ◽  
Kazuaki KAWAI ◽  
Vladimir A. TYURIN ◽  
Yulia Y. TYURINA ◽  
Grigory G. BORISENKO ◽  
...  
Keyword(s):  
Dna Cleavage ◽  
Caspase 3 ◽  
Protective Role ◽  
Membrane Phospholipids ◽  
No Donor ◽  
Redox Active ◽  
Apoptotic Effect ◽  
Transition And Heavy Metals ◽  
Apoptotic Effects

Intracellular safeguarding functions of metallothioneins (MTs) include sequestering transition and heavy metals, scavenging free radicals and protecting against electrophiles. We report that MT protection against Cu-induced cytotoxicity can be reversed and pro-oxidant and pro-apoptotic effects can be induced in HL-60 cells exposed to NO. We demonstrate that in ZnCl2-pretreated HL-60 cells loaded with copper nitrilotriacetate (Cu-NTA), exposure to an NO donor, S-nitroso-N-acetyl penicillamine, resulted in S-nitrosylation and oxidation of MT cysteines. This disruption of MT Cu-binding thiolate clusters caused loosening and release of redox-active Cu, enhanced redox-cycling activity of Cu and increased peroxidation of major classes of membrane phospholipids. We also found that Cu-induced oxidative stress in ZnCl2-pretreated/Cu-NTA-loaded HL-60 cells was accompanied by apoptosis documented by characteristic changes of nuclear morphology, internucleosomal DNA cleavage, externalization of phosphatidylserine, release of cytochrome c from mitochondria into cytosol and activation of caspase-3. We conclude that in Cu-challenged cells, NO can reverse the protective role of MTs and convert them into pro-oxidant, pro-apoptotic implements.

scholarly journals Hydrolysis of membrane phospholipids by phospholipases of rat liver lysosomes

1979 ◽  
Vol 182 (2) ◽  
pp. 599-606 ◽  
Author(s):  
Donald E. Richards ◽  
Robin F. Irvine ◽  
Rex M. C. Dawson
Keyword(s):  
Phospholipase C ◽  
Rat Liver ◽  
Lysosomal Enzymes ◽  
Microsomal Fraction ◽  
Water Soluble ◽  
Membrane Phospholipids ◽  
Liver Lysosomes ◽  
Rat Liver Lysosomes ◽  
Hydrolysis Of

(1) The hydrolysis of 32P- or myo-[2-3H]inositol-labelled rat liver microsomal phospholipids by rat liver lysosomal enzymes has been studied. (2) The relative rates of hydrolysis of phospholipids at pH4.5 are: sphingomyelin>phosphatidylethanolamine>phosphatidylcholine> phosphatidylinositol. (3) The predominant products of phosphatidylcholine and phosphatidylethanolamine hydrolysis are their corresponding lyso-compounds, indicating a slow rate of total deacylation. (4) Ca2+ inhibits the hydrolysis of all phospholipids, though only appreciably at high (>5mm) concentration. The hydrolysis of sphingomyelin is considerably less sensitive to Ca2+ than that of glycerophospholipids. (5) Analysis of the water-soluble products of phosphatidylinositol hydrolysis (by using myo-[3H]inositol-labelled microsomal fraction as a substrate) produced evidence that more than 95% of the product is phosphoinositol, which was derived by direct cleavage from phosphatidylinositol, rather than by hydrolysis of glycerophosphoinositol. (6) This production of phosphoinositol, allied with negligible lysophosphatidylinositol formation and a detectable accumulation of diacylglycerol, indicates that lysosomes hydrolyse membrane phosphatidylinositol almost exclusively in a phospholipase C-like manner. (7) Comparisons are drawn between the hydrolysis by lysosomal enzymes of membrane substrates and that of pure phospholipid substrates, and also the possible role of phosphatidylinositol-specific lysosomal phospholipase C in cellular phosphatidylinositol catabolism is discussed.

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