Organ-specific stress induces mouse pancreatic keratin overexpression in association with NF-kappaB activation.
Keratin polypeptides 8 and 18 (K8/K18) are the major intermediate filament proteins of pancreatic acinar cells and hepatocytes. Pancreatic keratin function is unknown, whereas hepatocyte keratins protect from mechanical and non-mechanical forms of stress. We characterized steady-state pancreatic keratin expression in Balb/c mice after caerulein and choline-deficient ethionine-supplemented diet (CDD), or on exposure to the generalized stresses of heat and water immersion. Keratins were studied at the protein, RNA and organizational levels. Isolated acini were used to study the role of nuclear factor (NF)-kappaB using selective inhibitors. Keratins were found to be abundant proteins making up 0.2%, 0.3% and 0.5% of the total cellular protein of pancreas, liver and small intestine, respectively. Caerulein and CDD caused a threefold transcription-mediated overall increase in K8/K18/K19/K20 proteins. Keratin overexpression begins on tissue recovery, peaks 2 days after caerulein injection, or 1 day after CDD discontinuation, and returns to basal levels after 10 days. K19/K20-containing cytoplasmic filaments are nearly absent pre-injury but form post-injury then return to their original membrane-proximal distribution after 10 days. By contrast, generalized stresses of heat or water-immersion stress do not alter keratin expression levels. Caerulein-induced keratin overexpression is associated with NF-kappaB activation when tested using ex vivo acinar cell cultures. In conclusion, keratins are abundant proteins that can behave as stress proteins in response to tissue-specific but not generalized forms of injury. Pancreatic keratin overexpression is associated with NF-kappaB activation and may serve unique functions in acinar or ductal cell response to injury.
Zhong
Bihui
B
VA Palo Alto Health Care System, Department of Medicine, 3801 Miranda Avenue, 154J, Palo Alto, CA 94304, USA.
Zhou
Qin
Q
Toivola
Diana M
DM
Tao
Guo-Zhong
GZ
Resurreccion
Evelyn Z
EZ
Omary
M Bishr
MB
D000818:Animals; D002108:Ceruletide / Q000494:pharmacology; D002796:Choline Deficiency; D004032:Diet; D005001:Ethionine / Q000494:pharmacology; D005334:Fever / Q000235:genetics / Q000378:metabolism; D005786:Gene Expression Regulation; D006358:Hot Temperature; D007421:Intestine, Small / Q000378:metabolism; D007633:Keratins / Q000235:genetics* / Q000378:metabolism*; D008099:Liver / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D016328:NF-kappa B / Q000378:metabolism*; D009928:Organ Specificity; D010179:Pancreas / Q000187:drug effects / Q000378:metabolism*; D010195:Pancreatitis / Q000139:chemically induced / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D012333:RNA, Messenger / Q000378:metabolism; D015533:Transcriptional Activation / Q000187:drug effects; D014867:Water / Q000494:pharmacology
D016328:NF-kappa B; D012333:RNA, Messenger; D014867:Water; D007633:Keratins; D002108:Ceruletide; D005001:Ethionine