Factor associated with neutral sphingomyelinase activation and its role in cardiac cell death.
Generation of proapoptotic sphingolipids by neutral sphingomyelinase activation is an early response to hypoxia/reoxygenation (HR) in cardiomyocytes. Factor associated with neutral sphingomyelinase activation (FAN) mediates activation of sphingomyelinase and subsequent apoptosis. However, the participation of FAN in HR-induced cardiomyocyte cell death has not been elucidated. We therefore investigated the expression and role of FAN in rat cardiomyocytes. A cDNA was isolated from rat heart encoding putative rat FAN. Reverse transcriptase-polymerase chain reaction, immunoelectron microscopy, and immunofluorescence demonstrated for the first time the expression of FAN specifically in rat cardiomyocytes. FAN expression was confirmed by the finding that expression of a dominant-negative FAN almost completely abrogated HR-induced cell death, whereas overexpression of wild-type FAN led to an increase. Treatment of FAN and dominant-negative FAN--expressing cells with C2-ceramide produced substantial cell death, indicating dominant-negative FAN exerts its protective action by interfering with the activation of the sphingolipid cascade. Taking these results together, we conclude that FAN is a previously undescribed and important HR signaling component in the heart and that inhibition of FAN may provide a novel intervention point for reducing ischemia/reperfusion injury.
O'Brien
Nicole W
NW
Department of Biology, San Diego State University, 5500 Campanile Dr, San Diego, CA 92182-4614, USA.
Gellings
Nicole M
NM
Guo
Mei
M
Barlow
Steven B
SB
Glembotski
Christopher C
CC
Sabbadini
Roger A
RA
D033942:Adaptor Proteins, Vesicular Transport / Q000737:chemistry / Q000502:physiology*; D000595:Amino Acid Sequence; D000818:Animals; D017209:Apoptosis; D015687:Cell Hypoxia; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D051379:Mice; D008969:Molecular Sequence Data; D032383:Myocytes, Cardiac / Q000166:cytology / Q000378:metabolism*; D011506:Proteins / Q000737:chemistry / Q000502:physiology*; D051381:Rats; D016415:Sequence Alignment
D033942:Adaptor Proteins, Vesicular Transport; D047908:Intracellular Signaling Peptides and Proteins; C102036:NSMAF protein, human; C491112:Nsmaf protein, mouse; C491113:Nsmaf protein, rat; D011506:Proteins