Regulator of calcineurin 1 controls growth plasticity of adult pancreas

Gastroenterology. 2010 Aug;139(2):609-19, 619.e1-6. doi: 10.1053/j.gastro.2010.04.050. Epub 2010 Jun 18.

Abstract

Background & aims: Growth of exocrine pancreas is regulated by gastrointestinal hormones, notably cholecystokinin (CCK). CCK-driven pancreatic growth requires calcineurin (CN), which activates Nuclear Factor of Activated T cells (NFATs), but the genetic underpinnings and feedback mechanisms that regulate this response are not known.

Methods: Pancreatic growth was stimulated by protease inhibitor (PI)-containing chow, which induces secretion of endogenous CCK. Expression profiling of PI stimulation was performed on Affymetrix 430A chips, and CN was inhibited via FK506. Exocrine pancreas-specific overexpression of CN inhibitor Regulator of Calcineurin 1 (Rcan1) was achieved by breeding elastase-Cre(estrogen receptor [ER]) transgenics with "flox-on" Rcan1 mice.

Results: CN inhibitor FK506 blocked expression of 38 genes, as confirmed by quantitative polymerase chain reaction. The CN-dependent genes were linked to growth-related processes, whereas their promoters were enriched in NFAT and NFAT/AP1 sites. Multiple NFAT targets, including Rcan1, Rgs2, HB-EGF, Lif, and Gem, were validated by chromatin immunoprecipitation. One of these, a CN feedback inhibitor Rcan1, was induced >50 fold during 1-8 hours course of pancreatic growth and strongly inhibited (>99%) by FK506. To examine its role in pancreatic growth, we overexpressed Rcan1 in an inducible, acinar-specific fashion. Rcan1 overexpression inhibited CN-NFAT signaling, as shown using an NFAT-luciferase reporter and quantitative polymerase chain reaction. Most importantly, the increase in exocrine pancreas size, protein/DNA content, and acinar proliferation were all blocked in Rcan1 overexpressing mice.

Conclusions: We profile adaptive pancreatic growth, identify Rcan1 as an important new feedback regulator, and firmly establish that CN-NFAT signaling is required for this response.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Calcineurin / metabolism
  • Calcineurin Inhibitors
  • Calcium-Binding Proteins
  • Cell Proliferation*
  • Cholecystokinin / metabolism*
  • Diet
  • Enzyme Inhibitors / pharmacology
  • Feedback, Physiological
  • Gabexate / administration & dosage
  • Gabexate / analogs & derivatives
  • Gene Expression Profiling / methods
  • Gene Expression Regulation
  • Integrases / genetics
  • Intracellular Signaling Peptides and Proteins / genetics
  • Intracellular Signaling Peptides and Proteins / metabolism*
  • Male
  • Mice
  • Mice, Inbred ICR
  • Mice, Transgenic
  • Muscle Proteins / genetics
  • Muscle Proteins / metabolism*
  • NFATC Transcription Factors / metabolism
  • NIH 3T3 Cells
  • Oligonucleotide Array Sequence Analysis
  • Organ Size
  • Pancreas / drug effects
  • Pancreas / growth & development
  • Pancreas / metabolism*
  • Pancreatic Elastase / genetics
  • Protease Inhibitors / administration & dosage
  • Receptor, Cholecystokinin A / genetics
  • Receptor, Cholecystokinin A / metabolism
  • Receptors, Estrogen / genetics
  • Signal Transduction / drug effects
  • Tacrolimus / pharmacology
  • Time Factors
  • Transfection

Substances

  • Calcineurin Inhibitors
  • Calcium-Binding Proteins
  • DSCR1 protein, mouse
  • Enzyme Inhibitors
  • Intracellular Signaling Peptides and Proteins
  • Muscle Proteins
  • NFATC Transcription Factors
  • Protease Inhibitors
  • Receptor, Cholecystokinin A
  • Receptors, Estrogen
  • camostat
  • Gabexate
  • Cholecystokinin
  • Cre recombinase
  • Integrases
  • Calcineurin
  • Pancreatic Elastase
  • Tacrolimus