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Characterization of ultrastructure and its relation with DNA fragmentation in Fas‐induced apoptosis of cultured cardiac myocytes
Author(s) -
Takemura Genzou,
Kato Satoshi,
Aoyama Takuma,
Hayakawa Yukihiro,
Kanoh Motoo,
Maruyama Rumi,
Arai Masazumi,
Nishigaki Kazuhiko,
Minatoguchi Shinya,
Fukuda Kazunori,
Fujiwara Takako,
Fujiwara Hisayoshi
Publication year - 2001
Publication title -
the journal of pathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.964
H-Index - 184
eISSN - 1096-9896
pISSN - 0022-3417
DOI - 10.1002/1096-9896(2000)9999:9999<::aid-path794>3.0.co;2-l
Subject(s) - dna fragmentation , tunel assay , apoptosis , fragmentation (computing) , apoptotic dna fragmentation , biology , microbiology and biotechnology , programmed cell death , ultrastructure , in situ nick end labeling , myocyte , biochemistry , anatomy , ecology
The purposes of the present study were to define precisely the ultrastructural features of apoptosis in cultured cardiomyocytes and to determine whether DNA fragmentation is essential for the apoptotic morphology. When cultured neonatal murine cardiomyocytes were incubated with an agonistic anti‐Fas antibody in the presence of a non‐toxic amount of actinomycin D or cycloheximide, approximately 70% of them had lost their viability after 24 h. The dead cardiomyocytes showed the typical ultrastructural changes of apoptosis on transmission and scanning electron microscopy, as well as by positive in situ nick end‐labelling (TUNEL), positive Taq polymerase‐based in situ ligation, a DNA ladder pattern on gel electrophoresis, and an increase in the active fragment of caspase‐3. According to TUNEL at the electron microscopic level, apoptotic nuclear change, cytoplasmic shrinkage, and DNA fragmentation always occurred simultaneously in apoptotic cardiomyocytes. Other ultrastructural features of apoptosis were the appearance of abundant lipid‐like structures in the cytoplasm of cardiomyocytes at the early phase, and a high incidence of plasma membrane rupture and formation of apoptotic bodies at the later phase. When zinc, an inhibitor of Ca 2+ /Mg 2+ ‐dependent endonuclease, was added to the present model, activation of caspase‐3 and an apoptotic ultrastructure were still observed in spite of the lack of DNA fragmentation, indicating that this type of myocyte death is also apoptosis. In conclusion, the typical apoptotic ultrastructure and DNA fragmentation occur simultaneously in association with caspase‐3 activation in Fas‐stimulated cultured cardiomyocytes. Apoptotic morphology can, however, be observed even without DNA fragmentation. Copyright © 2000 John Wiley & Sons, Ltd.