Radiation Protection: Phospholipase A.

Dmitri Popov. PhD Radiobiology, MD (Russia),Advanced Medical Technology and Systems Inc.

Canada.

Phospholipase A.

• Research Proposal: Radiation Protection : Phospholipase A.• Dmitri Popov• Full-text Research Proposal · Mar 2016• Add resources• File name: RadiationProtectionPhospholipaseA.pptx

DOI: 10.13140/RG.2.1.4878.7445

Phospholipase A

• Key words: phospholipase A2, phospholipase A2 receptor (PLA2R),

• Phospholipase C.

Phospholipase A.

• The present research relates generally to the fields of radiation biology, toxicology and medicine.

• The blocking antibodies reduce effects of ionizing radiation and protect cells and reduce toxic effects of radiation.

Phospholipase A.

• A phospholipase is an enzyme that hydrolyzes phospholipids into fatty acids and other lipophilic substances. There are four major classes, termed A, B, C and D, distinguished by the type of reaction which they catalyze:

• Phospholipase A• Phospholipase A1 - cleaves the SN-1 acyl chain.• Phospholipase A2 - cleaves the SN-2 acyl chain, releasing arachidonic acid.

• Phospholipase B - cleaves both SN-1 and SN-2 acyl chains; this enzyme is also known as a lysophospholipase.

Phospholipase A.

• Phospholipase C - cleaves before the phosphate, releasing diacylglycerol and a phosphate-containing head group. Phospholipase Cs play a central role in signal transduction, releasing the second messenger inositol triphosphate.

• Phospholipase D - cleaves after the phosphate, releasing phosphatidic acid and an alcohol.

• Types C and D are considered phosphodiesterases.• Phospholipase A2 acts on the intact lecithin molecule and hydrolyses the fatty acid

esterified to the second carbon atom. The resulting products are lysolecithin and a fatty acid. Phospholipase A2 is an enzyme present in the venom of bees and viper snakes

Heckmann LH, Sibly RM, Timmermans MJ, Callaghan A - Front. Zool. (2008)

Citation: Antiviral Therapy 2012; 17:485-493

doi: 10.3851/IMP1990

Dingzhi Wang & Raymond N. DuBoisNature Reviews Cancer 10, 181-193 (March 2010)

doi:10.1038/nrc2809

[Mediator function of molecular factors--lipoxygenase enzyme systems during exposure to ionizing radiation].

Budnitskaia EV. Radiobiologiia. 1986 Jul-Aug;26(4):435-46.

• “review of the national literature on the mediatory function of lipoxygenase systems affected by ionizing radiation, reports data on the functional role of lipoxygenases, their regulator--mediate contribution to radiation response of plants and animals. The latest data are submitted concerning the biological regulatory systems, eicosanoids--leukotrienes, formed under the effect of lipoxygenases which catalyse oxidation of polyunsaturated arachidonic acid (20:4). The structure and function of leukotrienes are described for these are necessary in studying the biochemical functions of lipoxygenases after ionizing irradiation. Emphasis is made on biologically active leukotrienes which take part in biological processes involved in inflammatory and hypersensitive reactions under the effect of radiation. Possible involvement of the lipoxygenase systems in metabolism regulation, its resistance and activation in a living body during development of radiopathological processes. The modelling concepts are considered for perspective radiation research aimed at biotechnological utilisation of lipoxygenases. Some regularities of mediatory function of lipoxygenase systems have been found. An assumption has been made that lipoxygenases and leukotrienes play an important role in the life of irradiated cells and tissues.”

Snake Venom Phospholipases A, Jeanne F’rigent-Dachary From the Laboratoire d’Hematologie,

Universite de Bordeaux II, France

• “Some purified phospholipases A2 originating from different snake venoms have been shown to possess anticoagulant properties . It appears that they inhibit blood coagulation via their action on phospholipids . It is well known that certain phospholipids accelerate clot formation by providing a surface on which the clotting factors interact “

Snake Venom Phospholipases A, Jeanne F’rigent-Dachary From the Laboratoire

d’Hematologie, Universite de Bordeaux II, France

• Anticoagulant phospholipases are able to bind both classes of phospholipids whatever their fluidities. Therefore in usual mixtures of pro-coagulant lipids, i.e. PC-PS binary systems, these phospholipases can interact with all lipids and compete with clotting factors for the same interface area. Furthermore, these phospholipases hydrolyze both classes of lipids, then the degraded interface can no longer serve as pro-coagulant surface.

https://en.wikipedia.org/wiki/Blocking_antibody

• A blocking antibody is an antibody that does not have a reaction when combined with an antigen, but prevents other antibodies from combining with that antigen.

•  This function of blocking antibodies has had a variety of clinical and experimental uses.

• The term can also be used for inhibiting antibody, prozone phenomenon and, agglutination reaction.

Phospholipase A2 or Phospholipase A2 membrane receptors Antibodies.

Inhibition of protein kinases blocks radiation-mediated gene induction and prevent radiation induced apoptosis (Uckun et al., 1992), necrosis and increase radiation survival (Hallahan et al., 1992)).

Photochem Photobiol. 1993 Feb;57(2):383-90.Ultraviolet radiation-induced phospholipase A2 activation occurs in mammalian cell membrane

preparations.Cohen D1, DeLeo VA.

• Ultraviolet erythema in human skin is mediated in part by membrane derivatives of arachidonic acid (AA). UVA (320-400 nm) and UVB (290-320 nm) have been shown to induce release of AA from intact mammalian cells in culture. In order to investigate the mechanism of this release we examined the effect of UVA and UVB on release of [3H] AA from membrane preparations of murine fibroblasts. C3H 10T1/2 cells were prelabelled for 24 h with [3H] AA. The membrane fractions of the cells were separated after lysis by differential centrifugation. The membranes were irradiated in suspension and the [3H] AA released from the membranes was determined by scintillation spectroscopy of supernatants 3-4 h after irradiation. 

Photochem Photobiol. 1993 Feb;57(2):383-90.Ultraviolet radiation-induced phospholipase A2 activation occurs in mammalian cell membrane

preparations.Cohen D1, DeLeo VA.

• Both UVA and UVB induced release of AA from the membrane preparations. The response to UVB was small but significant, reaching levels approximately 150% of control release at doses of 1,200-4,000 J/m2. The response to UVA was larger; doses of 2.5-5.0 J/cm2 induced release equal to twice control (200%) levels, while doses of 10-20 J/cm2 induced maximal release at levels approximately 400% of control. Time course studies with UVB and UVA showed maximal release at 4 h after irradiation. When the membrane preparations were incubated with a polyclonal anti-phospholipase A2 antibody the UV induced release of [3H] AA was completely inhibited in both UVB (1200 J/m2) and UVA (10 J/cm2) treated cells.+

Cytosolic phospholipase A2 regulates viability of irradiated vascular endothelium.

Cell Death and Differentiation (2008) 15, 1641–1653; doi:10.1038/cdd.2008.93; published online 20 June 200. E M Yazlovitskaya

1,2, A G Linkous1, D K Thotala1, K C Cuneo1 and D E Hallahan1,2,3

• “Radiosensitivity of various normal tissues is largely dependent on radiation-triggered signal transduction pathways. Radiation simultaneously initiates distinct signaling from both DNA damage and cell membrane. Specifically, DNA strand breaks initiate cell-cycle delay, strand-break repair or programmed cell death, whereas membrane-derived signaling through phosphatidylinositol 3-kinase/Akt and mitogen-activated protein kinase/extracellular signal-regulated kinase (ERK) enhances cell viability. Activation of cytosolic phospholipase A2 (cPLA2) and production of the lipid second-messenger lysophosphatidylcholine were identified as initial events (within 2 min) required for radiation-induced activation of Akt and ERK1/2 in vascular endothelial cells.”

Cytosolic phospholipase A2 regulates viability of irradiated vascular endothelium.

Cell Death and Differentiation (2008) 15, 1641–1653; doi:10.1038/cdd.2008.93; published online 20 June 200. E

M Yazlovitskaya1,2, A G Linkous1, D K Thotala1, K C Cuneo1 and D E Hallahan1,2,3

• “Inhibition of cPLA2 significantly enhanced radiation-induced cytotoxicity due to an increased number of multinucleated giant cells and cell cycle-independent accumulation of cyclin B1 within 24–48 h of irradiation. Delayed programmed cell death was detected at 72–96 h after treatment. Endothelial functions were also affected by inhibition of cPLA2 during irradiation resulting in attenuated cell migration and tubule formation.”

Cytosolic phospholipase A2 regulates viability of irradiated vascular endothelium.

Cell Death and Differentiation (2008) 15, 1641–1653; doi:10.1038/cdd.2008.93; published online 20 June 200. E

M Yazlovitskaya1,2, A G Linkous1, D K Thotala1, K C Cuneo1 and D E Hallahan1,2,3• “The role of cPLA2 in the regulation of radiation-

induced activation of Akt and ERK1/2 and cell viability was confirmed using human umbilical vein endothelial cells transfected with shRNA for cPLA2α and cultured embryonic fibroblasts from cPLA2α−/− mice. In summary, an immediate radiation-induced cPLA2-dependent signaling was identified that regulates cell viability and, therefore, represents one of the key regulators of radioresistance of vascular endothelial cells.”

Ionizing Radiation Acts on Cellular Membranes to Generate Ceramide and Initiate Apoptosis By Adriana Haimovitz-

Friedman, Chu-Cheng Kan,* Desiree Ehleiter, Roger S. Persaud, Maureen McLoughlin, Zvi Fuks, and Richard N. Kolesnick*

• Recent investigations provided evidence that the sphingomyelin signal transduction pathway mediates apoptosis for tumor necrosis factor c~ (TNF-o 0 in several hematopoietic and nonhematopoietic ceils. In this pathway, TNF-receptor interaction initiates sphingomyelin hydrolysis to ceramide by a sphingomyelinase.

Ionizing Radiation Acts on Cellular Membranes to Generate Ceramide and Initiate Apoptosis By Adriana Haimovitz-

Friedman, Chu-Cheng Kan,* Desiree Ehleiter, Roger S. Persaud, Maureen McLoughlin, Zvi Fuks, and Richard N. Kolesnick*

• In this pathway, TNF-receptor interaction initiates sphingomyelin hydrolysis to ceramide by a sphingomyelinase. Ceramide acts as a second messenger stimulating a ceramide-activated serine/threonine protein kinase. The present studies show that ionizing radiation, like TNF, induces rapid sphingomyelin hydrolysis to ceramide and apoptosis in bovine aortic endothelial cells. Elevation of ceramide with exogenous ceramide analogues was su~cient for induction of apoptosis.

Ionizing Radiation Acts on Cellular Membranes to Generate Ceramide and Initiate Apoptosis By Adriana Haimovitz-

Friedman, Chu-Cheng Kan,* Desiree Ehleiter, Roger S. Persaud, Maureen McLoughlin, Zvi Fuks, and Richard N. Kolesnick*

• Protein kinase C activation blocked both radiation-induced sphingomyelin hydrolysis and apoptosis, and apoptosis was restored by ceramide analogues added exogenously. Ionizing radiation acted directly on membrane preparations devoid of nuclei, stimulating sphingomyelin hydrolysis enzymatically through a neutral sphingomyelinase. These studies provide the first conclusive evidence that apoptotic signaling can be generated by interaction of ionizing radiation with cellular membranes and suggest an alternative to the hypothesis that direct DNA damage mediates radiation-induced cell kill.

Conclusion

• In conclusion, our opinion suggests that anti-PLA2 antibodies could work as a specific marker for irradiated mammals. It also indicates that there is a common pathophysiology among irradiated mammals with Acute Radiation Syndromes and Chronic Radiation Disease.

• Development of anti-PLA2 antibodies which will work as a sensitive biomarker may provide new tools such as ELISA for diagnosis, Acute Radiation Syndromes severity monitoring, and invention of new immune - therapy strategies in Acute Radiation Syndromes.

Literature.

• Biochimica et Biophysica Acta (BBA) - Biomembranes• Volume 604, Issue 2, 30 September 1980, Pages 191-246• H. Van Den Bosch• Intracellular phospholipases A.

Literature

• Boffa, M.-C., Rothen, C., Verheij, H. M., Verger, R., and de Xaas,

• 2. Boffa, M.-C., and Boffa, G. A. (1976) Biochim. Biophys. Acta • 3. Papahadjopoulos, D., and Hanahan, D. J. (1964) Biochim.

Literature.

• Snake Venom Phospholipases A, A FLUORESCENCE STUDY OF THEIR BINDING TO PHOSPHOLIPID VESICLES CORRELATION WITH THEIR ANTICOAGULANT ACTIVITIES‘

• Jeanne F’rigent-Dachary From the Laboratoire d’Hematologie, Universite de Bordeaux II, 33076, Bordeaux Cedex France et al.

Literature.

• Carter et al., "Tyrosine phosphorylation of phospholipase C induced by membrane immunoglobulin in B lymphocytes," Proc. Natl. Acad. Sci. USA, 88:2745-2749, 1991.

Literature.

• Hallahan et al., "Molecular Basis for the Use of Glucocorticoids, Nonsteroidals and Pentoxifylline to Minimize the Acute Effects of Radiotherapy," Cancer Research, 51:4565-4569, 1991.

Literature.

• Hallahan et al., "Tumor Necrosis Factor Gene Expression Is Mediated by Protein Kinase C following Activation by Ionizing Radiation," Cancer Research, 51:4565-4569, 1991.

Literature.

• Nishizuka, "Intracellular Signaling by Hydrolysis of Phospholipids and Activation of Protein Kinase C," Science, 258:607-614, 1992.

Literature.

• Uckun et al., "Ionizing radiation stimulates unidentified tyrosine-specific protein kinases in human B-lymphocyte precursors, triggering apoptosis and clonogenic cell death," Proc. Natl. Acad. Sci. USA, 89:9005-9009, 1992.

Literature.

• Uckun et al., "Tyrosine phosphorylation is a mandatory proximal step in radiation-induced activation of the protein kinase C signaling pathway in human B-lymphocyte precursors," Proc. Natl. Acad. Sci. USA, 90:252-256, 1993.

Literature.

• Prostaglandins and Inflammation • Emanuela Ricciotti, PhD and Garret A. FitzGerald, MD.*

Institute for Translational Medicine and Therapeutics, University of Pennsylvania, Philadelphia, Pa.

• Published in final edited form as: Arterioscler Thromb Vasc Biol. 2011 May ; 31(5): 986–1000. doi:10.1161/ATVBAHA.110.207449.

Literature.

• Cytosolic phospholipase A2 regulates viability of irradiated vascular endothelium.Cell Death and Differentiation (2008) 15, 1641–1653; doi:10.1038/cdd.2008.93; published online 20 June 200. E M Yazlovitskaya1,2, A G Linkous1, D K Thotala1, K C Cuneo1 and D E Hallahan1,2,3

Literature.

• Kolesnick R, Fuks Z. Radiation and ceramide-induced apoptosis. Oncogene 2003; 22: 5897–5906.

Literature.

• . Haimovitz-Friedman A, Kan CC, Ehleiter D, Persaud RS, McLoughlin M, Fuks Z et al. Ionizing radiation acts on cellular membranes to generate ceramide and initiate apoptosis. J Exp Med 1994; 180: 525–535.

Literature.

• Valerie K, Yacoub A, Hagan MP, Curiel DT, Fisher PB, Grant S et al. Radiation-induced cell signaling: inside-out and outside-in. Mol Cancer Ther 2007; 6: 789–801.

Literature.

• Farooqui AA, Horrocks LA. Phospholipase A2-generated lipid mediators in the brain: the good, the bad, and the ugly. Neuroscientist 2006; 12: 245–260.

Literature.

• Hirabayashi T, Murayama T, Shimizu T. Regulatory mechanism and physiological role of cytosolic phospholipase A2. Biol Pharm Bull 2004; 27: 1168–1173.