Suppression of apoptosis in the protein kinase Cdelta null mouse in vivo.
Protein kinase C (PKC) delta is an essential regulator of mitochondrial dependent apoptosis in epithelial cells. We have used the PKCdelta(-/-) mouse to ask if loss of PKCdelta protects salivary glands against gamma-irradiation-induced apoptosis in vivo and to explore the mechanism underlying protection from apoptosis. We show that gamma-irradiation in vivo results in a robust induction of apoptosis in the parotid glands of wild type mice, whereas apoptosis is suppressed by greater than 60% in the parotid glands of PKCdelta(-/-) mice. Primary parotid cells from PKCdelta(-/-) mice are defective in mitochondrial dependent apoptosis as indicated by suppression of etoposide-induced cytochrome c release, poly(ADP-ribose) polymerase cleavage, and caspase-3 activation. Notably, apoptotic responsiveness can be restored by re-introduction of PKCdelta by adenoviral transduction. Etoposide and gamma-irradiation-induced activation of p53 is similar in primary parotid cells and parotid glands from PKCdelta(+/+) and PKCdelta(-/-) mice, indicating that PKCdelta functions downstream of the DNA damage response. In contrast, activation of the c-Jun amino-terminal kinase is reduced in primary parotid cells from PKCdelta(-/-) cells and in parotid C5 cells, which express a dominant inhibitory mutant of PKCdelta. Similarly, c-Jun amino-terminal kinase activation is suppressed in vivo in gamma-irradiated parotid glands from PKCdelta(-/-) mice. These studies indicate an essential role for PKCdelta downstream of the p53 response and upstream of the c-Jun amino-terminal kinase activation in DNA damage-induced apoptosis in vivo and in vitro.
Humphries
Michael J
MJ
Department of Craniofacial Biology and School of Dentistry, University of Colorado Health Sciences Center, Aurora, Colorado 80262, USA.
Limesand
Kirsten H
KH
Schneider
Jonathan C
JC
Nakayama
Keiichi I
KI
Anderson
Steven M
SM
Reyland
Mary E
ME
D000256:Adenoviridae / Q000235:genetics; D000818:Animals; D017209:Apoptosis / Q000235:genetics* / Q000502:physiology; D004249:DNA Damage; D005260:Female; D005720:Gamma Rays / Q000009:adverse effects; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008928:Mitochondria / Q000502:physiology; D051745:Protein Kinase C-delta / Q000235:genetics* / Q000378:metabolism*; D012469:Salivary Glands / Q000166:cytology / Q000473:pathology* / Q000528:radiation effects*; D014161:Transduction, Genetic; D016159:Tumor Suppressor Protein p53 / Q000502:physiology
D016159:Tumor Suppressor Protein p53; D051745:Protein Kinase C-delta; D048031:JNK Mitogen-Activated Protein Kinases