Autophagic cell death of pancreatic acinar cells in serine protease inhibitor Kazal type 3-deficient mice.
OBJECTIVE
Serine protease inhibitor Kazal type 1 (SPINK1), which is structurally similar to epidermal growth factor, is thought to inhibit trypsin activity and to prevent pancreatitis. Point mutations in the SPINK1 gene seem to predispose humans to pancreatitis; however, the clinical significance of SPINK1 mutations remains controversial. This study aimed to elucidate the role of SPINK1.


METHODS
We generated Spink3-deficient (Spink3(-/-)) mice by gene targeting in mouse embryonic stem cells. Embryonic and neonatal pancreases were analyzed morphologically and molecularly. Specific probes were used to show the typical autophagy that occurs during acinar cell death.


RESULTS
In Spink3(-/-) mice, the pancreas developed normally up to 15.5 days after coitus. However, autophagic degeneration of acinar cells, but not ductal or islet cells, started from day 16.5 after coitus. Rapid onset of cell death occurred in the pancreas and duodenum within a few days after birth and resulted in death by 14.5 days after birth. There was limited inflammatory cell infiltration and no sign of apoptosis. At 7.5 days after birth, residual ductlike cells in the tubular complexes strongly expressed pancreatic duodenal homeodomain-containing protein 1, a marker of pancreatic stem cells, without any sign of acinar cell regeneration.


CONCLUSIONS
The progressive disappearance of acinar cells in Spink3(-/-) mice was due to autophagic cell death and impaired regeneration. Thus, Spink3 has essential roles in the maintenance of integrity and regeneration of acinar cells.
Ohmuraya
Masaki
M
Division of Developmental Genetics, Institute of Molecular Embryology and Genetics, Kumamoto University, Japan.
Hirota
Masahiko
M
Araki
Masatake
M
Mizushima
Noboru
N
Matsui
Makoto
M
Mizumoto
Takao
T
Haruna
Kyoko
K
Kume
Shoen
S
Takeya
Motohiro
M
Ogawa
Michio
M
Araki
Kimi
K
Yamamura
Ken-Ichi
K
D000818:Animals; D001707:Biopsy, Needle; D015153:Blotting, Western; D016923:Cell Death / Q000502:physiology*; D002478:Cells, Cultured; D002108:Ceruletide; D004247:DNA / Q000032:analysis; D004195:Disease Models, Animal; D007150:Immunohistochemistry; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D010179:Pancreas / Q000166:cytology*; D010186:Pancreatic Function Tests; D010195:Pancreatitis / Q000378:metabolism / Q000473:pathology*; D010587:Phagocytosis / Q000502:physiology; D012313:RNA / Q000032:analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012680:Sensitivity and Specificity; D015842:Serine Proteinase Inhibitors / Q000378:metabolism; D014359:Trypsin Inhibitor, Kazal Pancreatic / Q000378:metabolism*
D015842:Serine Proteinase Inhibitors; D014359:Trypsin Inhibitor, Kazal Pancreatic; D012313:RNA; D002108:Ceruletide; D004247:DNA