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P4-12 Pulpal inflammation and incidence of coronary heart disease
Abstracts/Intemalional Journal of Cardiology 97 SuppL 2 (2004) S1~75 P4-11 NITRIC OXIDE INHIBITS ENDOTHELIN-I-INDUCED CARDIOMYOCYTE HYPERTROPHY THROUGH C G M P - M E D I A T E D S U P P R E S S I O N OF E X T R A C E L L U L A R . S I G N A L R E G U L A T E D K I N A S E ACTIVATION
Tzu Hurng Cheng 1, Cheng Hsien Chen 1, Jin Jet Chen 2. 1Department of
Medicine. Taipei Medical University. 2Department of Internal Medicine. National Talwan University Hospital and National Talwan University College of Medicine, Talpei, Talwan Introdeution: Cardiac hypertrophy is a compensath~2¢ mechanism in response to a variety of cardiovascular diseases. Recently, ditrfo oxide (NO) has been demonstmted to be involved in the pathogenesis of atherosclerosis, however, the role of this free radical in the development of cardiac hypertrophy remains unclear. In this study, we investigate NO modulation of cellular signaling in endothelin 1 (ET 1) induced cardiomyocyte hypertrophy in culture. M e t h o d s a n d Results: Northern blot and reverse transcription pdlymerase chain reaction analysis revealed ET ~eceptor subtype ETA predominated on cardiomyocytes. ET 1 treatment of cardiomyocytes in creased constitutive NO synthase activity and induced NO production via the sthndiation of ET receptor subtype ETs, the minority subtype on cardiomyocytes. We previously reported that ET 1 induces ROS gen eration via ETA ~ecepthr and ROS modulate c-fos expression. Using Northern blot analysis and chloramphenicdl acetyltransferase assay, we found that NO suppressed ET 14nduced c-fos mRNA level and promoter activity. Contrarily, ET 1 stimulation of c-fos expression was augmented by depletion of endogenous NO generation with the addition of NO scav enger PTIO into cardiomyocytes. Ceils cotransfected with the dominant negative and positive mutants of signaling molecules reveaied that the Ras/Raf/extmcelldiar signai regulated kinase (ERK) signaling pathway is involved in ET 14nduced c-fos gene expression, We further demonstrated that NO di~ectiy inhibited ET 1 induced ERK1/2 phosphorylation and activation in a cGMP dependent manner, indicating that NO modulates ET 1 induced c-fos expression via its inhibitory effect on ERK signaling pathway. Using electrophoretic mobility shift assay, the ET 1 stimulated activator protein 1 DNA binding activity was attenuated by NO. Finally, using [3H] leucine incorporaiion and immunocytochemistrG we estab lished that NO attenuates the enhanced protein synthesis and sarcomere assembly, the chai-acteristic morphdlogicai change in cardiomyocytes induced by agonist ET 1. C o n c l u s i o n : Taken thgethe~; our findings provide the molecular basis of NO as a negative regulator in ET 1 induced cardiac hypertrophy.
$57
In the NHS, we included CHD cases 1989 1998, and controls matched on age and smoking (N 457). Results: Compared to men without RCT, those with >1 RCT had a multivmiate RR of 1.21 (95% CI 1.05 1.40) for CHD. The association was limited to the dentists (RR 1.38; 95% CI 1.14 1.67). There was no association among the non dentists nmles (RR 1.04) or NHS females (RR 1.05). Cmies was not associated with CHD. C o n c l u s i o n s : The results suggest a marginal association between pdipai iilflammation and CHD. This research was supported by grants DE12102, HL34595, HL35464 and CA87969, CA55075 from the National Institute of Health,
P4-13 SPHINGOLIPID CERAMIDE IMPAIRS HERG K ÷ CHANNEL F U N C T I O N : I N V O L V E M E N T OF M U L T I P L E P R O T E I N K I N A S E S AND ROLE OF REACTIVE OXYGEN SPECIES AS A MEDIATOR Jingxiong Wang, Yiqiang Zhang, Fdi Yu, Zhiguo Wang. Research Center,
Montreal Heart Institute, Montreal, PQ H1 T 1C8, the Department of Medicine, University of Montreal, Montreal, PQ H3C 3J7, Canada Ceramide, a splringolipid me tabolite, has emerged as a key second messen ger molecule that mediates multiple cellular functions, and its accumulation in ischemic myocardium and failing heart has been associated with the pathological processes. To investigate whether ceramide modulates HERG current (IHERG), a critical determinant of cardiac repdlmizaiion, we performed whdle.zell patch clamp studies in HERG expressing HEK293 ceils. Cthonic incubation with membrane permeable ceramide for 10 ths caused pronounced IHERG inhibition in a concentration dependent fashion and slight positive shift of voltage dependent HERG activation. Production of endogenous ce~'amide with sphingomyelinase produced similar effects. ~I)¢rosine kinase inhibitors failed to reverse the effects of cemmide. Activators of protein kinase A (PKA) or protein kinase C (PKC) mimicked, and inhiblio~s of these kinases prevented, the effects of ceramide. The inhiblio~3J effect of ceramide, PKA or PKC was reversed by antioxidants vitanrin E and MnTBAP on IHERG, but the rightward shift of HERG activation was unaffected by the antioxidants. Exposure of ceils to ceramide or PKA/PKC activators markedly increased the intracelldiar level of reactive oxygen species (ROS), which was abolished by pretreab ment with the antioxidants. We conclude that ceramide depresses IHERG directly via ROS overproduction, or indirectly via PKA/PKC activation and HERG impairment by ceramide might contribute to the electrical disturbance in ischemic heart.
P4-12 PULPAL INFLAMMATION AND INCIDENCE OF CORONARY HEART DISEASE
P4-14 T H E M3 R E C E P T O R - M E D I A T E D K + C U R R E N T PROTEIN-COUPLED K + CHANNEL
Kaumudi J. Joslripura 1,2, Waranuch Pitiphat 1&3, Hsin Ctha Hung 1')'4, Waiter C. Willett 9,5,6, Graham A. Colditz 9,6, Chester W. Douglass1.2
Hong Sift, Huizhen Wang, Zthguo Wang. Research Center (HH, HW,, ZW), Montreal Heart Institute, Montreal, PQ HIT 1C8, the Department of Medicine (ZW), University of Montreal, Montreal, PQ H3C 3J7 Canada
Department of Oral Health Policy and Epidemiology1 Harvard School of Dental Medicine; Deparl~nent of Epidemiology2, Harvard School of Public Health; Department of Community Dentistry. Khon Kaen University, 77utilanS ; Institute of Health Care Management, National Sun Yal-sen University, Talwat142 Department of Nutrition ~, Harvard School of Public Health, Channing Laboralory 6 and the Division of Preventive Medicine, Department of Medicine, Brig~tam and Women's Hospital, and Harvard Medical School Introduction: This study evaluates the association between pdipai ii~l am mation and incident coronary heart disease (CHD). Pdipai inflammation caused primat51y by coronai caries is a micro infection leading to root canal treatment (RCT). M e t h o d s : We report results among males from the Health Professionais Follow Up Study (HPFS) and females from the Nurses' Health Study (NHS). We excluded participants with prior cardiovascular disease or diabetes, We obtained root canal data from the HPFS cohort (N 34,670).
(IKM3):A GQ
Stimulation of muscarmic acetylcholine recepthl~ (mAChRs) can activate an inward rectifier K + current (I~ch), which is mediated by the M2 subtype of mAChR in cardiac myocytes. Recently, a novel delayed rectifier like K + current mediated by activation of the cardiac M3 leceptors (designated IKM3) was identified, which is distinct from I ~ c h and other known K + currents. While I ~ c h is known to be a G i protein gated K + channel, the signal transduction mechadisms for IKM3 activation remained unexplored. We studied IKM3 with whole cell patch clamp and macropateh clamp techniques. Whole cell IKM3 activated by choline persisted with ~NiRmai rundown over 2 hom-s in presence of intemai GTR When GTP was replaced by GDP ~S, IKM3demonstrated rapid and extensive rundown. While IKACh (induced by ACh) was markedly reduced in cells pretreated with perthssis toxin (PTX), IKM3 was unaitered. Intracelidiar application of antibodies targeting ~ subudit of Gi/o protein suppressed IKACh without affecting IKM3. Antibodies targeting the N and the C terminus, respectively, of
Tzu Hurng Cheng 1, Cheng Hsien Chen 1, Jin Jet Chen 2. 1Department of
Medicine. Taipei Medical University. 2Department of Internal Medicine. National Talwan University Hospital and National Talwan University College of Medicine, Talpei, Talwan Introdeution: Cardiac hypertrophy is a compensath~2¢ mechanism in response to a variety of cardiovascular diseases. Recently, ditrfo oxide (NO) has been demonstmted to be involved in the pathogenesis of atherosclerosis, however, the role of this free radical in the development of cardiac hypertrophy remains unclear. In this study, we investigate NO modulation of cellular signaling in endothelin 1 (ET 1) induced cardiomyocyte hypertrophy in culture. M e t h o d s a n d Results: Northern blot and reverse transcription pdlymerase chain reaction analysis revealed ET ~eceptor subtype ETA predominated on cardiomyocytes. ET 1 treatment of cardiomyocytes in creased constitutive NO synthase activity and induced NO production via the sthndiation of ET receptor subtype ETs, the minority subtype on cardiomyocytes. We previously reported that ET 1 induces ROS gen eration via ETA ~ecepthr and ROS modulate c-fos expression. Using Northern blot analysis and chloramphenicdl acetyltransferase assay, we found that NO suppressed ET 14nduced c-fos mRNA level and promoter activity. Contrarily, ET 1 stimulation of c-fos expression was augmented by depletion of endogenous NO generation with the addition of NO scav enger PTIO into cardiomyocytes. Ceils cotransfected with the dominant negative and positive mutants of signaling molecules reveaied that the Ras/Raf/extmcelldiar signai regulated kinase (ERK) signaling pathway is involved in ET 14nduced c-fos gene expression, We further demonstrated that NO di~ectiy inhibited ET 1 induced ERK1/2 phosphorylation and activation in a cGMP dependent manner, indicating that NO modulates ET 1 induced c-fos expression via its inhibitory effect on ERK signaling pathway. Using electrophoretic mobility shift assay, the ET 1 stimulated activator protein 1 DNA binding activity was attenuated by NO. Finally, using [3H] leucine incorporaiion and immunocytochemistrG we estab lished that NO attenuates the enhanced protein synthesis and sarcomere assembly, the chai-acteristic morphdlogicai change in cardiomyocytes induced by agonist ET 1. C o n c l u s i o n : Taken thgethe~; our findings provide the molecular basis of NO as a negative regulator in ET 1 induced cardiac hypertrophy.
$57
In the NHS, we included CHD cases 1989 1998, and controls matched on age and smoking (N 457). Results: Compared to men without RCT, those with >1 RCT had a multivmiate RR of 1.21 (95% CI 1.05 1.40) for CHD. The association was limited to the dentists (RR 1.38; 95% CI 1.14 1.67). There was no association among the non dentists nmles (RR 1.04) or NHS females (RR 1.05). Cmies was not associated with CHD. C o n c l u s i o n s : The results suggest a marginal association between pdipai iilflammation and CHD. This research was supported by grants DE12102, HL34595, HL35464 and CA87969, CA55075 from the National Institute of Health,
P4-13 SPHINGOLIPID CERAMIDE IMPAIRS HERG K ÷ CHANNEL F U N C T I O N : I N V O L V E M E N T OF M U L T I P L E P R O T E I N K I N A S E S AND ROLE OF REACTIVE OXYGEN SPECIES AS A MEDIATOR Jingxiong Wang, Yiqiang Zhang, Fdi Yu, Zhiguo Wang. Research Center,
Montreal Heart Institute, Montreal, PQ H1 T 1C8, the Department of Medicine, University of Montreal, Montreal, PQ H3C 3J7, Canada Ceramide, a splringolipid me tabolite, has emerged as a key second messen ger molecule that mediates multiple cellular functions, and its accumulation in ischemic myocardium and failing heart has been associated with the pathological processes. To investigate whether ceramide modulates HERG current (IHERG), a critical determinant of cardiac repdlmizaiion, we performed whdle.zell patch clamp studies in HERG expressing HEK293 ceils. Cthonic incubation with membrane permeable ceramide for 10 ths caused pronounced IHERG inhibition in a concentration dependent fashion and slight positive shift of voltage dependent HERG activation. Production of endogenous ce~'amide with sphingomyelinase produced similar effects. ~I)¢rosine kinase inhibitors failed to reverse the effects of cemmide. Activators of protein kinase A (PKA) or protein kinase C (PKC) mimicked, and inhiblio~s of these kinases prevented, the effects of ceramide. The inhiblio~3J effect of ceramide, PKA or PKC was reversed by antioxidants vitanrin E and MnTBAP on IHERG, but the rightward shift of HERG activation was unaffected by the antioxidants. Exposure of ceils to ceramide or PKA/PKC activators markedly increased the intracelldiar level of reactive oxygen species (ROS), which was abolished by pretreab ment with the antioxidants. We conclude that ceramide depresses IHERG directly via ROS overproduction, or indirectly via PKA/PKC activation and HERG impairment by ceramide might contribute to the electrical disturbance in ischemic heart.
P4-12 PULPAL INFLAMMATION AND INCIDENCE OF CORONARY HEART DISEASE
P4-14 T H E M3 R E C E P T O R - M E D I A T E D K + C U R R E N T PROTEIN-COUPLED K + CHANNEL
Kaumudi J. Joslripura 1,2, Waranuch Pitiphat 1&3, Hsin Ctha Hung 1')'4, Waiter C. Willett 9,5,6, Graham A. Colditz 9,6, Chester W. Douglass1.2
Hong Sift, Huizhen Wang, Zthguo Wang. Research Center (HH, HW,, ZW), Montreal Heart Institute, Montreal, PQ HIT 1C8, the Department of Medicine (ZW), University of Montreal, Montreal, PQ H3C 3J7 Canada
Department of Oral Health Policy and Epidemiology1 Harvard School of Dental Medicine; Deparl~nent of Epidemiology2, Harvard School of Public Health; Department of Community Dentistry. Khon Kaen University, 77utilanS ; Institute of Health Care Management, National Sun Yal-sen University, Talwat142 Department of Nutrition ~, Harvard School of Public Health, Channing Laboralory 6 and the Division of Preventive Medicine, Department of Medicine, Brig~tam and Women's Hospital, and Harvard Medical School Introduction: This study evaluates the association between pdipai ii~l am mation and incident coronary heart disease (CHD). Pdipai inflammation caused primat51y by coronai caries is a micro infection leading to root canal treatment (RCT). M e t h o d s : We report results among males from the Health Professionais Follow Up Study (HPFS) and females from the Nurses' Health Study (NHS). We excluded participants with prior cardiovascular disease or diabetes, We obtained root canal data from the HPFS cohort (N 34,670).
(IKM3):A GQ
Stimulation of muscarmic acetylcholine recepthl~ (mAChRs) can activate an inward rectifier K + current (I~ch), which is mediated by the M2 subtype of mAChR in cardiac myocytes. Recently, a novel delayed rectifier like K + current mediated by activation of the cardiac M3 leceptors (designated IKM3) was identified, which is distinct from I ~ c h and other known K + currents. While I ~ c h is known to be a G i protein gated K + channel, the signal transduction mechadisms for IKM3 activation remained unexplored. We studied IKM3 with whole cell patch clamp and macropateh clamp techniques. Whole cell IKM3 activated by choline persisted with ~NiRmai rundown over 2 hom-s in presence of intemai GTR When GTP was replaced by GDP ~S, IKM3demonstrated rapid and extensive rundown. While IKACh (induced by ACh) was markedly reduced in cells pretreated with perthssis toxin (PTX), IKM3 was unaitered. Intracelidiar application of antibodies targeting ~ subudit of Gi/o protein suppressed IKACh without affecting IKM3. Antibodies targeting the N and the C terminus, respectively, of