H9c2 cardiac myoblasts undergo apoptosis in a model of ischemia consisting of serum deprivation and hypoxia: inhibition by PMA.
Cardiac myocytes undergo apoptosis under condition of ischemia. Little is known, however, about the molecular pathways that mediate this response. We show that serum deprivation and hypoxia, components of ischemia in vivo, resulted in apoptosis of rat ventricular myoblast cells H9c2. Hypoxia alone did not induce significant apoptosis for at least 48 h, but largely increased the proapoptotic action of serum deprivation. H9c2 cells apoptosis is evidenced by an increase in terminal (TdT)-mediated dUTP nick end-labeling-positive nuclei and by activation of caspases 3, 6, 7 and 9, and loss of mitochondrial functions. In this model of simulated ischemia, represented by serum deprivation plus hypoxia, cardiomyoblasts apoptosis was associated with a p53-independent Bax accumulation and with a down-regulation of Bcl-xL, whereas the levels of cIAP-1, cIAP-2 and X-IAP proteins did not change. Phorbol-12-myristate-13-acetate significantly reduced the induction of apoptosis, inhibiting caspase 3 cleavage, Bax accumulation, Bcl-xL down-regulation as well as restoring cell viability.
Bonavita
Francesca
F
Department of Biochemistry 'G. Moruzzi', University of Bologna, Via Irnerio, 48 40126 Bologna, Italy. bonavita@biocfarm.unibo.it
Stefanelli
Claudio
C
Giordano
Emanuele
E
Columbaro
Marta
M
Facchini
Annalisa
A
Bonafè
Francesca
F
Caldarera
Claudio Marcello
CM
Guarnieri
Carlo
C
D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D020169:Caspases / Q000378:metabolism; D015687:Cell Hypoxia; D002460:Cell Line; D016895:Culture Media, Serum-Free; D008928:Mitochondria / Q000502:physiology; D032386:Myoblasts, Cardiac / Q000166:cytology / Q000378:metabolism* / Q000502:physiology; D017202:Myocardial Ischemia / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000096:biosynthesis; D051381:Rats; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*
D016895:Culture Media, Serum-Free; D019253:Proto-Oncogene Proteins c-bcl-2; D020169:Caspases; D013755:Tetradecanoylphorbol Acetate