Pancreatic thread protein is mitogenic to pancreatic-derived cells in culture.
OBJECTIVE
Pancreatic thread proteins (PTPs) are acinar cell products and members of the regenerating gene (reg) family. reg expression increases during islet regeneration, is depressed during aging-related islet dysfunction, and may be important in beta-cell growth and maintenance. The aim of this study was to examine the genetic expression of reg in pancreatic-derived cells in vitro and the mitogenic effect of PTP/reg protein on these cells.


METHODS
reg gene expression was measured by Northern analysis in three rat pancreatic cell lines: ARIP (ductal), AR42J (acinar), and RIN (beta-cell). PTP/reg protein was isolated from bovine and human pancreas. Cells were cultured with PTP/reg for 72 hours, and thymidine incorporation was measured.


RESULTS
reg messenger RNA was detected in AR42J but not in ARIP or RIN. PTP/reg protein was mitogenic to RIN and ARIP in a dose-related fashion but not to AR42J. It was not mitogenic to cultured mature rat islets.


CONCLUSIONS
reg messenger RNA is expressed in acinar but not in beta-cell or ductal pancreatic cell lines. PTP/reg protein was mitogenic to both beta-cell and ductal cell lines but not to mature, nondividing islets. This supports the hypothesis that PTP/reg protein is an acinar cell-derived mediator of beta-cell growth and may be involved in modulating the duct-to-islet axis.
Zenilman
M E
ME
Department of Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
Magnuson
T H
TH
Swinson
K
K
Egan
J
J
Perfetti
R
R
Shuldiner
A R
AR
D000818:Animals; D015152:Blotting, Northern; D002135:Calcium-Binding Proteins / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology*; D002417:Cattle; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D015870:Gene Expression; D006801:Humans; D007515:Islets of Langerhans / Q000166:cytology; D051847:Lithostathine; D008297:Male; D008934:Mitogens / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology*; D009419:Nerve Tissue Proteins; D010179:Pancreas / Q000166:cytology / Q000378:metabolism*; D010183:Pancreatic Ducts / Q000166:cytology; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats
D002135:Calcium-Binding Proteins; D051847:Lithostathine; D008934:Mitogens; D009419:Nerve Tissue Proteins; C497617:REG1A protein, human; D012333:RNA, Messenger; C497616:Reg1a protein, rat