JNK3 Signaling Pathway Activates Ceramide Synthase Leading to Mitochondrial Dysfunction

Abstract

A cardinal feature of brain tissue injury in stroke is mitochondrial dysfunction leading to cell death, yet remarkably little is known about the mechanisms underlying mitochondrial injury in cerebral ischemia/reperfusion (IR). Ceramide, a naturally occurring membrane sphingolipid, functions as an important second messenger in apoptosis signaling and is generated by de novo synthesis, sphingomyelin hydrolysis, or recycling of sphingolipids. In this study, cerebral IR-induced ceramide elevation resulted from ceramide biosynthesis rather than from hydrolysis of sphingomyelin. Investigation of intracellular sites of ceramide accumulation revealed the elevation of ceramide in mitochondria because of activation of mitochondrial ceramide synthase via post-translational mechanisms. Furthermore, ceramide accumulation appears to cause mitochondrial respiratory chain damage that could be mimicked by exogenously added natural ceramide to mitochondria. The effect of ceramide on mitochondria was somewhat specific; dihydroceramide, a structure closely related to ceramide, did not inflict damage. Stimulation of ceramide biosynthesis seems to be under control of JNK3 signaling: IR-induced ceramide generation and respiratory chain damage was abolished in mitochondria of JNK3-deficient mice, which exhibited reduced infarct volume after IR. These studies suggest that the hallmark of mitochondrial injury in cerebral IR, respiratory chain dysfunction, is caused by the accumulation of ceramide via stimulation of ceramide synthase activity in mitochondria, and that JNK3 has a pivotal role in regulation of ceramide biosynthesis in cerebral IR. A cardinal feature of brain tissue injury in stroke is mitochondrial dysfunction leading to cell death, yet remarkably little is known about the mechanisms underlying mitochondrial injury in cerebral ischemia/reperfusion (IR). Ceramide, a naturally occurring membrane sphingolipid, functions as an important second messenger in apoptosis signaling and is generated by de novo synthesis, sphingomyelin hydrolysis, or recycling of sphingolipids. In this study, cerebral IR-induced ceramide elevation resulted from ceramide biosynthesis rather than from hydrolysis of sphingomyelin. Investigation of intracellular sites of ceramide accumulation revealed the elevation of ceramide in mitochondria because of activation of mitochondrial ceramide synthase via post-translational mechanisms. Furthermore, ceramide accumulation appears to cause mitochondrial respiratory chain damage that could be mimicked by exogenously added natural ceramide to mitochondria. The effect of ceramide on mitochondria was somewhat specific; dihydroceramide, a structure closely related to ceramide, did not inflict damage. Stimulation of ceramide biosynthesis seems to be under control of JNK3 signaling: IR-induced ceramide generation and respiratory chain damage was abolished in mitochondria of JNK3-deficient mice, which exhibited reduced infarct volume after IR. These studies suggest that the hallmark of mitochondrial injury in cerebral IR, respiratory chain dysfunction, is caused by the accumulation of ceramide via stimulation of ceramide synthase activity in mitochondria, and that JNK3 has a pivotal role in regulation of ceramide biosynthesis in cerebral IR. Mitochondria are known to be involved in both necrotic and apoptotic cell death, both of which have been identified in the ischemia/reperfusion (IR) 2The abbreviations used are:IRischemia/reperfusionJNKc-Jun N-terminal kinaseWTwild typeMCAOmiddle cerebral artery occlusionVDACvoltage-dependent anion channelERendoplasmic reticulumFCCPcarbonyl cyanide p-trifluoromethoxyphenylhydrazoneMSmass spectrometryMS/MStandem mass spectrometryTTC2,3,5-triphenyltetrazolium chlorideICAinternal carotid arteryFB1fumonisin B1. 2The abbreviations used are:IRischemia/reperfusionJNKc-Jun N-terminal kinaseWTwild typeMCAOmiddle cerebral artery occlusionVDACvoltage-dependent anion channelERendoplasmic reticulumFCCPcarbonyl cyanide p-trifluoromethoxyphenylhydrazoneMSmass spectrometryMS/MStandem mass spectrometryTTC2,3,5-triphenyltetrazolium chlorideICAinternal carotid arteryFB1fumonisin B1. -injured brain(1Nicotera P. Lipton S.A. J. Cereb. Blood Flow Metab. 1999; 19: 583-591Crossref PubMed Scopus (142) Google Scholar, 2Green D.R. Reed J.C. Science. 1998; 281: 1309-1312Crossref PubMed Google Scholar, 3Chan P.H. Stroke. 2004; 35: 2748-2750Crossref PubMed Scopus (51) Google Scholar). Also, restricted respiratory chain function has been found to develop in various models of cerebral IR (4Ozawa K. Seta K. Araki H. Handa H. J. Biochem. (Tokyo). 1967; 61: 512-514Crossref PubMed Scopus (77) Google Scholar, 5Rehncrona S. Mela L. Siesjo B.K. Stroke. 1979; 10: 437-446Crossref PubMed Scopus (297) Google Scholar, 6Sims N.R. Pulsinelli W.A. J. Neurochem. 1987; 49: 1367-1374Crossref PubMed Scopus (142) Google Scholar, 7Sims N.R. Zaidan E. Int. J. Biochem. Cell Biol. 1995; 27: 531-550Crossref PubMed Scopus (80) Google Scholar, 8Zaidan E. Sims N.R. J. Neurochem. 1994; 63: 1812-1819Crossref PubMed Scopus (113) Google Scholar); specifically, mitochondrial respiration supported either by glutamate or succinate was decreased up to 40%, but ascorbate-supported respiration was not significantly altered (9Anderson M.F. Sims N.R. J. Neurochem. 1999; 73: 1189-1199Crossref PubMed Scopus (73) Google Scholar, 10Sims N.R. Anderson M.F. Neurochem. Int. 2002; 40: 511-526Crossref PubMed Scopus (281) Google Scholar). Mitochondrial changes appear to be one essential step in tissue damage in cerebral IR. Treatments that slow tissue impairment were associated with better recovery of mitochondrial function (11Kuroda S. Katsura K. Hillered L. Bates T.E. Siesjo B.K. Neurobiol. Dis. 1996; 3: 149-157Crossref PubMed Scopus (119) Google Scholar, 12Nakai A. Kuroda S. Kristian T. Siesjo B.K. Neurobiol. Dis. 1997; 4: 288-300Crossref PubMed Scopus (96) Google Scholar). ischemia/reperfusion c-Jun N-terminal kinase wild type middle cerebral artery occlusion voltage-dependent anion channel endoplasmic reticulum carbonyl cyanide p-trifluoromethoxyphenylhydrazone mass spectrometry tandem mass spectrometry 2,3,5-triphenyltetrazolium chloride internal carotid artery fumonisin B1. ischemia/reperfusion c-Jun N-terminal kinase wild type middle cerebral artery occlusion voltage-dependent anion channel endoplasmic reticulum carbonyl cyanide p-trifluoromethoxyphenylhydrazone mass spectrometry tandem mass spectrometry 2,3,5-triphenyltetrazolium chloride internal carotid artery fumonisin B1. A number of cell death regulatory molecules have been implicated in neuronal injury in IR, including c-Jun N-terminal kinase (JNK) (13Gillardon F. Spranger M. Tiesler C. Hossmann K.A. Brain Res. Mol. Brain Res. 1999; 73: 138-143Crossref PubMed Scopus (50) Google Scholar). Once activated, JNK can phosphorylate serine residues of several transcription factors, such as c-Jun, or non-nuclear proteins, including pro-apoptotic Bcl-2 family proteins (14Davis R.J. Cell. 2000; 103: 239-252Abstract Full Text Full Text PDF PubMed Scopus (3643) Google Scholar, 15Papadakis E.S. Finegan K.G. Wang X. Robinson A.C. Guo C. Kayahara M. Tournier C. FEBS Lett. 2006; 580: 1320-1326Crossref PubMed Scopus (79) Google Scholar, 16Schroeter H. Boyd C.S. Ahmed R. Spencer J.P. Duncan R.F. Rice-Evans C. Cadenas E. Biochem. J. 2003; 372: 359-369Crossref PubMed Scopus (158) Google Scholar, 17Gao Y. Signore A.P. Yin W. Cao G. Yin X.M. Sun F. Luo Y. Graham S.H. Chen J. J. Cereb. Blood Flow Metab. 2005; 25: 694-712Crossref PubMed Scopus (205) Google Scholar). Among three JNK isoforms encoded by different and are in JNK3 is in the and in the A role of JNK3 in cerebral has been of from brain IR injury G. C. J. R.J. P. S. A. 2003; PubMed Scopus Google Scholar). a role as second in intracellular signaling L. M. Brain Res. Brain Res. 2004; PubMed Scopus (113) Google Scholar, J. Biol. 2002; Full Text Full Text PDF PubMed Scopus Google ceramide, which is in cell death J. Biol. 2002; Full Text Full Text PDF PubMed Scopus Google Scholar). the of ceramide have been by that not the of naturally occurring that natural are generated by and either in to the generation or proteins to H. Cell Biol. 2005; Full Text Full Text PDF PubMed Scopus Google Scholar, 2004; 4: PubMed Scopus Google Scholar, W. J. H. A. E. Wang E. S. J.C. Y. H. M. 2006; PubMed Scopus Google Scholar, A. H. R. J.C. PubMed Scopus Google Scholar). a of ceramide on mitochondria in hydrolysis of a mitochondrial of sphingomyelin by to mitochondria resulted in In generation of ceramide in the endoplasmic reticulum or by to did not effect cell H. S. J. PubMed Scopus Google Scholar). novo of ceramide is to in the endoplasmic reticulum studies activity in mitochondria C. J. C. Biochem. J. 2004; PubMed Scopus Google Scholar, H. S. M. T. T. T. 1998; PubMed Scopus Google Scholar). synthase is a in de novo of ceramide PubMed Scopus Google Scholar, E. 2000; PubMed Scopus Google and in was identified as a of ceramide in resulted in in and C. J. Biol. 1994; Full Text PDF PubMed Google Scholar). of which to the were and H. Cell Biol. 2005; Full Text Full Text PDF PubMed Scopus Google Scholar). revealed the of and in brain Y. A. Y. Biochem. J. 2005; PubMed Scopus Google Scholar). of known of a of and a chain in Y. A. Y. Biochem. J. 2005; PubMed Scopus Google Scholar). has been that and or and and and and Y. A. Y. Biochem. J. 2005; PubMed Scopus Google Scholar, S. J.C. J. F. J. Biol. 2006; 281: Full Text Full Text PDF PubMed Scopus Google Scholar). the the ceramide synthase activity has been from mitochondria H. S. M. T. T. T. 1998; PubMed Scopus Google the of proteins in mitochondria to be A studies ceramide accumulation in brain via activation of and sphingomyelin hydrolysis M. M. T. A. H. H. Lett. 2000; PubMed Scopus Google Scholar, M. K. T. A. H. S. Res. 1996; PubMed Scopus Google and cerebral IR. with the of brain tissue damage was decreased in M. G. J. Mol. 2000; PubMed Scopus Google Scholar). The of this was to the of mitochondrial ceramide accumulation and role in cerebral IR-induced mitochondrial that ceramide biosynthesis rather than sphingomyelin hydrolysis the accumulation of ceramide in mitochondria. that several ceramide, including and are in mitochondria, and appears to be by IR. Furthermore, that accumulation of ceramide could mitochondrial respiratory chain activity the of a of regulation of ceramide biosynthesis in IR in that IR-induced stimulation of ceramide synthase in mitochondria and the mitochondrial respiratory chain damage were abolished in JNK3-deficient These suggest that activation of ceramide synthase cerebral IR-induced mitochondrial injury and is by JNK3 and were to JNK3-deficient by of were and were from anion channel was from was from and were from was by was from was from as as used were by the the of and of were and by the and of of and the of were to as J. Cereb. 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Biol. 1997; Full Text Full Text PDF PubMed Scopus Google Scholar). mitochondria are in the and mitochondrial with either of glutamate and or succinate in the of or in the of and The of mitochondrial was by a respiratory control in mitochondria from the of the control is as the in the of the and by the in the in the of Mitochondria with respiratory control of were used respiration was in the of and in mass J. Biol. 2002; Full Text Full Text PDF PubMed Scopus Google Scholar, S. K. S. J. W. J.C. J. Biol. 2004; Full Text Full Text PDF PubMed Scopus Google Scholar, C. M. H. de L. J. Biol. Full Text Full Text PDF PubMed Scopus Google resulted in mass spectrometry of that the of to by in an J. A. 2006; PubMed Scopus Google Scholar). or were in a and of and which was on a in a or with internal were with to and in of The were on the and from the with a The the and internal were and with the were by of to the internal The from the were to internal and with the a from mitochondria were by as H. J. 2006; PubMed Scopus Google Scholar, T.E. J. 2002; PubMed Google Scholar). were by in were by to with in and and with were a activity was as L. P. J. Cell Biol. PubMed Scopus Google Scholar). mitochondrial ceramide synthase a to the activity in E. 2000; PubMed Scopus Google Scholar, J.C. C. C. R. Wang J. A. J. Biol. 2003; Full Text Full Text PDF PubMed Scopus Google Scholar). ceramide the of and A to that is the of the a of natural as a synthase activity was by an accumulation of tandem of of mitochondria and the that could on the of the mitochondrial the activity was in the of a used in activity of membrane and in of activity H. S. J. Res. 2006; Full Text Full Text PDF PubMed Scopus Google Scholar, Biochem. Metab. Biol. 1994; PubMed Scopus Google Scholar). Mitochondria or were in of and with The was with of and activity was in the or of ceramide synthase fumonisin were by activity was as of of were of with a which was to the IR of in Brain in brain tissue after of by of were from the or of the brain and by tandem IR significantly ceramide, dihydroceramide, and of stimulation of de novo ceramide R. M. A. K. R. Cell. 1995; Full Text PDF PubMed Scopus Google Scholar, J. Biol. 2002; Full Text Full Text PDF PubMed Scopus Google of in of sphingomyelin not the that ceramide is because of activation of sphingomyelin hydrolysis The accumulation of seems to the were changes in after is in with that that both and the of to tissue damage by different mechanisms P.H. Stroke. 2004; 35: 2748-2750Crossref PubMed Scopus (51) Google Scholar). In to ceramide are by including and The of ceramide was after of cerebral by of of changes in sphingomyelin in in a changes in ceramide in are in a a are are with activation of ceramide biosynthesis in the brain after IR. be that IR has sphingomyelin the that was activation of sphingomyelin in in sphingomyelin but a in ceramide from in intracellular on mitochondria which are an important intracellular involved in cell to IR. IR of in that ceramide not in the but in mitochondria or C. J. C. Biochem. J. 2004; PubMed Scopus Google Scholar, H. S. M. T. T. T. 1998; PubMed Scopus Google Scholar, K. J. J. J. Biol. 2006; 281: Full Text Full Text PDF PubMed Scopus Google Scholar). mitochondrial ceramide biosynthesis is by cerebral IR, mitochondria on a as E. Sims N.R. J. Neurochem. 1994; 63: 1812-1819Crossref PubMed Scopus (113) Google Scholar, J. 2000; PubMed Google Scholar). was to the of mitochondria and mitochondria and the of mitochondria, the activity of the was in mitochondrial and The activity of the was of of in the activity was of of in mitochondria. The of mitochondria with was than revealed that dihydroceramide, and ceramide were in both and mitochondria after IR The of in pro-apoptotic in mitochondria and a important role of accumulation of ceramide in intracellular in in mitochondria, which are of cell was in of sphingomyelin either in or in mitochondria IR the sphingomyelin was in mitochondria, sphingomyelin was in mitochondria from The suggest that IR the activation of de novo ceramide biosynthesis in mitochondria. the ceramide in and mitochondria after IR. The of ceramide was in from an brain In in mitochondria, the of three ceramide was including and The suggest that could in mitochondria as as in and is by IR. the of chain and of Y. A. Y. Biochem. J. 2005; PubMed Scopus Google the suggest that different family could be by IR in mitochondria with of several isoforms of ceramide including and has been in brain Y. A. Y. Biochem. J. 2005; PubMed Scopus Google Scholar). the of family proteins in mitochondria and found that and proteins in the and were in the mitochondria. IR-induced accumulation of and in mitochondria is with activation of activation of could not be is not by IR in IR to the such as or that are generated by Y. A. Y. Biochem. J. 2005; PubMed Scopus Google Scholar). the of mitochondrial activation in IR, the of proteins was in mitochondria from or revealed changes in or in mitochondria IR-induced brain injury appears that mitochondrial activation was not because of stimulation of transcription that in in mitochondria after cerebral IR. of in that IR could to of activity in mitochondria via post-translational mechanisms. synthase activity of was under to be and and which the was not Mitochondria from or brain were with or the ceramide synthase by G. Wang E. K. J. Biol. Full Text PDF PubMed Google that is a and of ceramide and the of ceramide serine is not by mitochondrial ceramide synthase activity was to is that IR-induced ceramide synthase activity in mitochondria was A IR-induced in ceramide synthase activity was in both the ceramide synthase and activity were to The of studies suggest that either IR activation of mitochondrial ceramide which is not involved in ceramide biosynthesis in mitochondria, or IR to mitochondrial ceramide both mitochondrial ceramide and could used to can Y. A. Y. Biochem. J. 2005; PubMed Scopus Google that is with in mitochondria. has been that generated in an was in K. C. J. H. J.C. J. Biol. 2002; Full Text Full Text PDF PubMed Scopus Google Scholar). the suggest that mitochondrial is by IR via post-translational mechanisms. with of accumulation of ceramide in mitochondria IR, ceramide accumulation mitochondrial on mitochondrial respiratory chain dysfunction that has been after or cerebral IR in the N.R. Pulsinelli W.A. J. Neurochem. 1987; 49: 1367-1374Crossref PubMed Scopus (142) Google Scholar, 7Sims N.R. Zaidan E. Int. J. Biochem. Cell Biol. 1995; 27: 531-550Crossref PubMed Scopus (80) Google Scholar). the role of ceramide accumulation in mitochondrial respiratory chain dysfunction in cerebral IR, the effect of ceramide on respiratory chain was in mitochondria from the was important to that could respiratory chain in a to respiratory chain damage. chain were to different respiratory chain including and by mitochondria the was in the of of The of mitochondrial respiration under the activity of respiratory chain is the ceramide in brain and in the brain and in mitochondria and in supported by glutamate or to the respiration in mitochondria from the brain (9Anderson M.F. Sims N.R. J. Neurochem. 1999; 73: 1189-1199Crossref PubMed Scopus (73) Google Scholar, 10Sims N.R. Anderson M.F. Neurochem. Int. 2002; 40: 511-526Crossref PubMed Scopus (281) Google Scholar). did not ascorbate-supported is the type of respiratory chain dysfunction that in mitochondria after cerebral IR (9Anderson M.F. Sims N.R. J. Neurochem. 1999; 73: 1189-1199Crossref PubMed Scopus (73) Google Scholar, 10Sims N.R. Anderson M.F. Neurochem. Int. 2002; 40: 511-526Crossref PubMed Scopus (281) Google the accumulation of in mitochondria. the of the effect on mitochondrial ceramide, of which the was in mitochondria The ceramide effect on mitochondrial respiration was not respiratory chain function to the of the effect on mitochondrial because was an accumulation of in mitochondria from the brain the of mitochondrial respiration was to and The of exogenously added to mitochondrial respiration could be to of the to mitochondria. the of or in mitochondria after the were with of either and by was of or of in mitochondria. from ceramide by of The suggest that the respiratory chain damage the of this as did not the respiratory chain is with the that ceramide pro-apoptotic intracellular but is not involved in cell apoptosis J. Biol. 2002; Full Text Full Text PDF PubMed Scopus Google Scholar, Science. PubMed Scopus Google and an important role in regulation of W. J. H. A. E. Wang E. S. J.C. Y. H. M. 2006; PubMed Scopus Google Scholar). the of ceramide to damage to the mitochondrial respiratory chain to IR-induced ceramide accumulation in mitochondria ceramide as a cause of mitochondrial respiratory chain in IR. of in Mitochondria of JNK3-deficient of JNK in the mitochondrial death is by studies of JNK and to the mitochondria C. Biol. 2005; PubMed Scopus Google Scholar). a role of JNK3 brain injury has been is a the of activity in of JNK3 not reduced but from brain injury after cerebral G. C. J. R.J. P. S. A. 2003; PubMed Scopus Google Scholar). JNK3 is involved in regulation of ceramide ceramide accumulation was in of JNK3-deficient after IR. or JNK3-deficient were to of by of G. C. J. R.J. P. S. A. 2003; PubMed Scopus Google the infarct volume in JNK3-deficient was significantly reduced with A and IR-induced elevation of ceramide was in JNK3-deficient These that the JNK3 signaling could activation of ceramide biosynthesis in cerebral IR. that IR-induced activation of mitochondrial ceramide biosynthesis is by JNK3 the ceramide was in mitochondria from JNK3-deficient The accumulation of or in the wild type was abolished in mitochondria from JNK3-deficient The decreased accumulation of ceramide in cerebral mitochondria of JNK3-deficient was not because of revealed in mitochondria from JNK3-deficient with wild type The of this that IR-induced stimulation of mitochondrial ceramide biosynthesis is under control of IR-induced in Mitochondria from JNK3-deficient a role of JNK3 signaling in IR-induced mitochondrial dysfunction, respiratory chain in mitochondria of JNK3-deficient after of of The respiratory chain were to different respiratory chain including and by mitochondria the was in the of of In mitochondria from mice, the decreased respiration of respiration supported by succinate an either in in The of in the respiration in the of a that IR The IR-induced in respiration in the of glutamate the in but of be In with the on mitochondrial damage after or cerebral IR in the N.R. Pulsinelli W.A. J. Neurochem. 1987; 49: 1367-1374Crossref PubMed Scopus (142) Google Scholar, 7Sims N.R. Zaidan E. Int. J. Biochem. Cell Biol. 1995; 27: 531-550Crossref PubMed Scopus (80) Google Scholar, M.F. Sims N.R. J. Neurochem. 1999; 73: 1189-1199Crossref PubMed Scopus (73) Google Scholar, 10Sims N.R. Anderson M.F. Neurochem. Int. 2002; 40: 511-526Crossref PubMed Scopus (281) Google the suggest that IR the mitochondrial respiratory chain the of IR-induced mitochondrial respiratory chain dysfunction was abolished in mitochondria from JNK3-deficient The suggest that signaling is IR-induced stimulation of ceramide accumulation in mitochondria, and mitochondrial respiratory chain damage. The studies that cerebral IR could the accumulation of ceramide in brain mitochondria via activation of ceramide synthase that resulted in the mitochondrial respiratory chain damage. The effect of ceramide on mitochondria was somewhat because dihydroceramide, a closely related to inflict the damage. These studies to mitochondrial of ceramide generation and regulation by JNK3 post-translational mechanisms. The revealed a role of JNK3 in the IR-induced activation of the of the ceramide ceramide which was found in mitochondria. sphingomyelin hydrolysis and de novo ceramide synthesis, have been implicated in the generation of an apoptotic be or in on or on the cell type A. M. M. M. R. J. Biol. 1999; Full Text Full Text PDF PubMed Scopus Google Scholar). The sphingomyelin is a signaling that and to the J. Biol. 2002; Full Text Full Text PDF PubMed Scopus Google Scholar, R. Cell. 1994; Full Text PDF PubMed Scopus Google Scholar, J. Biol. 1994; Full Text PDF PubMed Google Scholar). is by hydrolysis of which is in the membrane of hydrolysis after stimulation of to apoptotic signaling function ceramide by de novo has been identified R. M. A. K. R. Cell. 1995; Full Text PDF PubMed Scopus Google Scholar, 2002; PubMed Scopus Google Scholar). de novo after of brain to or M. J. M. J. 1999; PubMed Google Scholar, J. M. J. 2000; PubMed Google Scholar). The the of ceramide generation in IR a pivotal role of sphingomyelin hydrolysis and activation of In a was activity and reduced tissue damage after in M. G. J. Mol. 2000; PubMed Scopus Google Scholar). cerebral caused ceramide accumulation because of activation of sphingomyelin by reduced ceramide by synthase R. H. T. H. H. T. Brain Res. 2004; PubMed Scopus Google Scholar). studies suggest an of ceramide generation via activation of de novo and mitochondrial damage in IR. studies in brain tissue to by that of de novo ceramide biosynthesis dihydroceramide, and with a of sphingomyelin the of the of ceramide the of of ceramide in cell to IR. suggest that the of ceramide generation a role in and cell to pro-apoptotic H. S. J. PubMed Scopus Google Scholar, H. A. G. J. H. M. R. E. 2003; PubMed Scopus Google Scholar). In this mitochondrial generation of ceramide via activation of sphingomyelin hydrolysis has been to cell to J. Chen J. 2004; PubMed Scopus Google or H. C. S. Biochem. J. 2005; PubMed Scopus Google Scholar). studies suggest the that IR activation of the of ceramide ceramide leading to accumulation of several ceramide including and in mitochondria. three ceramide family and in mitochondria. of in the of proteins in the brain that activation of the post-translational mechanisms. The of ceramide in mitochondria are with IR-induced activation of which has been to and Y. A. Y. Biochem. J. 2005; PubMed Scopus Google Scholar). activation of to ceramide Y. A. Y. Biochem. J. 2005; PubMed Scopus Google Scholar, S. J.C. J. F. J. Biol. 2006; 281: Full Text Full Text PDF PubMed Scopus Google has not been the activity of and Y. A. Y. Biochem. J. 2005; PubMed Scopus Google on the different of ceramide synthase in mitochondria from and control be involved in in mitochondria. IR-induced stimulation of mitochondrial ceramide synthase activity was to the In the ceramide synthase activity was in control mitochondria, of activity that is in K. C. J. H. J.C. J. Biol. 2002; Full Text Full Text PDF PubMed Scopus Google Scholar). the suggest that mitochondrial ceramide in an mitochondrial is by IR, and activity is by the that several ceramide with different in mitochondria C. J. C. Biochem. J. 2004; PubMed Scopus Google Scholar). Furthermore, that are not in and this a activity in IR. In this study, the of ceramide synthase regulation by the of JNK3 on mitochondrial ceramide accumulation in to IR. c-Jun N-terminal one of in to a of such as and A. 2004; PubMed Scopus Google Scholar). have been by to phosphorylate and with transcription can a intracellular role of non-nuclear proteins, including various proteins of the family C. Biol. 2005; PubMed Scopus Google Scholar). of a that to the of mitochondria the of mitochondrial kinase In IR JNK that to the mitochondria to cell death J. H. K. Brain Res. Mol. Brain Res. 2003; PubMed Scopus Google Scholar). of a that JNK in the IR H. A. Cell 1999; PubMed Scopus Google Scholar). JNK proteins are encoded by three and that are to JNK studies in suggest that different JNK isoforms in cell of in are D.R. R.J. P. 1999; Full Text Full Text PDF PubMed Scopus Google Scholar, K.A. P. 2000; Full Text Full Text PDF PubMed Scopus Google Scholar). of the but not or from IR brain and G. C. J. R.J. P. S. A. 2003; PubMed Scopus Google Scholar, G. K.G. C. H. H. J. Cereb. Blood Flow Metab. 2006; 27: PubMed Scopus Google Scholar). The of JNK3 isoforms to be The proteins that the molecules of JNK3 in intracellular a role in the and JNK signaling C. Biol. 2005; PubMed Scopus Google Scholar). studies a JNK3 and activation of mitochondrial ceramide synthase on of the JNK3 signaling IR-induced ceramide generation and respiratory chain damage were abolished in mitochondria of JNK3-deficient that reduced infarct volume after IR. The of IR to the of a post-translational of regulation of on a of ceramide and the but not that JNK3 activation of in cerebral IR. the role of of JNK3 in the cell to IR. is in brain J.C. M. J. Res. 1998; PubMed Scopus Google which of with and cell in which is S. K. S. J. W. J.C. J. Biol. 2004; Full Text Full Text PDF PubMed Scopus Google Scholar). restricted tissue and activity as important mechanisms the of In this that cerebral IR the signaling to mitochondrial ceramide synthase leading to accumulation of ceramide and respiratory chain damage in mitochondria. the role of a intracellular signaling in the generation of and with of the the