Mechanism of induction of pancreatic acinar cell apoptosis by hydrogen sulfide.
The present study investigated the mechanism of mouse pancreatic acinar cell apoptosis induced by H(2)S in an in vitro system, using isolated pancreatic acini. Treatment of pancreatic acini with 10 microM NaHS (a donor of H(2)S) for 3 h caused phosphatidylserine externalization as shown by annexin V binding, an indicator of early stages of apoptosis. This treatment also resulted in the activation of the caspase cascade and major changes at the mitochondrial level. Caspase-3, -8, and -9 activities were stimulated by H(2)S treatment. Treatment with inhibitors of caspase-3, -8, and -9 significantly inhibited H(2)S-induced phosphatidylserine externalization as shown by reduced annexin V staining. The mitochondrial membrane potential was collapsed in H(2)S-treated acini as evidenced by fluorescence microscopy and quantitative analysis. Furthermore, the treatment of acini with H(2)S caused the release of cytochrome c by the mitochondria. To investigate the mechanism underlying pancreatic acinar cell apoptosis, we also characterized the protein expression of a range of molecules that are each known to influence the apoptotic pathway. Among proapoptotic proteins, Bax expression was activated in H(2)S-treated cells but not Bid, and the antiapoptotic proteins Bcl-X(L) and Bcl-2 did not show any activation in pancreatic acinar cell apoptosis. The death effector domain-containing protein Flip is downregulated in H(2)S-treated acini. These results demonstrate the induction of pancreatic acinar cell apoptosis in vitro by H(2)S and the involvement of both mitochondrial and death receptor pathways in the process of apoptosis.
Cao
Yang
Y
Department of Pharmacology, National University of Singapore, Yong Loo Lin School of Medicine, Bldg. MD2, 18 Medical Drive, Singapore 117597.
Adhikari
Sharmila
S
Ang
Abel Damien
AD
Moore
Philip K
PK
Bhatia
Madhav
M
D000818:Animals; D017304:Annexin A5 / Q000378:metabolism; D017209:Apoptosis; D051017:Apoptosis Regulatory Proteins / Q000378:metabolism; D015153:Blotting, Western; D020169:Caspases / Q000378:metabolism; D045304:Cytochromes c / Q000378:metabolism; D016650:Fluorescein-5-isothiocyanate; D006862:Hydrogen Sulfide / Q000494:pharmacology*; D066298:In Vitro Techniques; D008297:Male; D051379:Mice; D008928:Mitochondria / Q000378:metabolism; D010179:Pancreas / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D013440:Sulfides / Q000494:pharmacology
D017304:Annexin A5; D051017:Apoptosis Regulatory Proteins; D013440:Sulfides; D045304:Cytochromes c; D020169:Caspases; C025451:sodium bisulfide; D016650:Fluorescein-5-isothiocyanate; D006862:Hydrogen Sulfide