The mtDNA nt7778 G/T polymorphism augments formation of lymphocytic foci but does not aggravate cerulein-induced acute pancreatitis in mice

PLoS One. 2014 Jul 10;9(7):e102266. doi: 10.1371/journal.pone.0102266. eCollection 2014.

Abstract

A polymorphism in the ATP synthase 8 (ATP8) gene of the murine mitochondrial genome, G-to-T transversion at position 7778, has been suggested to increase susceptibility to multiple autoimmune diseases, including autoimmune pancreatitis (AIP). The polymorphism also induces mitochondrial reactive oxygen species generation, secretory dysfunction and β-cell mass adaptation. Here, we have used two conplastic mouse strains, C57BL/6N-mtAKR/J (B6-mtAKR; nt7778 G; control) and C57BL/6N-mtFVB/N (B6-mtFVB; nt7778 T), to address the question if the polymorphism also affects the course of cerulein-induced acute pancreatitis in mice. Therefore, two age groups of mice (3 and 12-month-old, respectively) were subjected to up to 7 injections of the secretagogue cerulein (50 µg/kg body weight) at hourly intervals. Disease severity was assessed at time points from 3 hours to 7 days based on pancreatic histopathology, serum levels of α-amylase and activities of myeloperoxidase (MPO) in lung tissue. A comparison of cerulein-induced pancreatic tissue damage and increases of α-amylase and MPO activities showed no differences between the age-matched groups of both strains. Interestingly, histological evaluation of pancreatic tissue of both untreated and cerulein-treated B6-mtAKR and B6-mtFVB mice also revealed the presence of infiltrates of immune cells surrounding ducts and vessels; a finding that is compatible with an early stage of AIP. After recovery from cerulein-induced pancreatitis (day 7 after the injections), 12-month-old B6-mtFVB mice but not B6-mtAKR mice displayed aggravated lymphocytic lesions. A comparison of 12-month-old mice with other age groups of both strains revealed that lymphocytic foci were largely absent in 3-month-old mice, while 24-month-old mice were more affected. Together, our data suggest that the mtDNA nt7778 G/T polymorphism does not aggravate cerulein-induced acute pancreatitis. Autoimmune-like lesions, however, may progress faster if additional tissue damage occurs.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Ceruletide / toxicity
  • DNA, Mitochondrial / genetics*
  • Humans
  • Lymphocytes / drug effects
  • Lymphocytes / enzymology
  • Lymphocytes / pathology
  • Mice
  • Mitochondria / enzymology
  • Mitochondria / genetics*
  • Mitochondria / pathology
  • Pancreatitis / chemically induced
  • Pancreatitis / genetics*
  • Pancreatitis / pathology
  • Peroxidase / metabolism
  • Polymorphism, Single Nucleotide / genetics
  • Reactive Oxygen Species / metabolism
  • alpha-Amylases / metabolism

Substances

  • DNA, Mitochondrial
  • Reactive Oxygen Species
  • Ceruletide
  • Peroxidase
  • alpha-Amylases

Grants and funding

This work was supported by a grant from the Bundesministerium für Bildung und Forschung (0315892A, GERONTOSYS program, http://www.bmbf.de/). The funder had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.