Toll-like receptor-4 genotype influences the survival of cystic fibrosis mice

JC Canale-Zambrano, ML Auger… - American Journal of …, 2010 - journals.physiology.org
JC Canale-Zambrano, ML Auger, CK Haston
American Journal of Physiology-Gastrointestinal and Liver …, 2010journals.physiology.org
Toll-like receptor (Tlr) 4 is a lipopolysaccharide (LPS) receptor that contributes to the
regulation of intestinal cell homeostasis, a condition that is altered in the intestines of cystic
fibrosis mice. Herein, we assessed whether Tlr4 genotype influences cystic fibrosis intestinal
disease by producing and phenotyping 12-wk (adult)-and 4-day (neonate)-old mice derived
from BALB cystic fibrosis transmembrane conductance regulator, Cftr+/tm1Unc and C. C3-
Tlr4 Lps-d/J (Tlr4−/−), progenitors. Intestinal disease was assayed through mouse survival …
Toll-like receptor (Tlr) 4 is a lipopolysaccharide (LPS) receptor that contributes to the regulation of intestinal cell homeostasis, a condition that is altered in the intestines of cystic fibrosis mice. Herein, we assessed whether Tlr4 genotype influences cystic fibrosis intestinal disease by producing and phenotyping 12-wk (adult)- and 4-day (neonate)-old mice derived from BALB cystic fibrosis transmembrane conductance regulator, Cftr+/tm1Unc and C.C3-Tlr4Lps-d/J (Tlr4−/−), progenitors. Intestinal disease was assayed through mouse survival, crypt-villus axis (CVA) length, cell proliferation, bacterial load, bacterial classification, inflammatory cell infiltrate, and mucus content measures. Of the 77 Cftr−/− (CF) mice produced, only one Cftr/Tlr4 double-mutant mouse lived to the age of 12 wk while the majority of the remainder succumbed at ∼4 days of age. The survival of CF Tlr4+/− mice exceeded that of both CF Tlr4+/+ and Cftr/Tlr4 double-mutant mice. Adult CF mice presented increased Tlr4 expression, CVA length, crypt cell proliferation, and bacterial load relative to non-CF mice, but no differences were detected in Tlr4+/− compared with Tlr4+/+ CF mice. The double-mutant neonates did not differ from Tlr4+/+ or Tlr4+/− CF mice by intestinal CVA length or bacterial load, but fewer Tlr4+/− CF neonates presented with luminal mucus obstruction in the distal ileum, and the intestinal mast cell increase of CF mice was not evident in double-mutant neonates. We conclude that Tlr4 deficiency reduces the survival, but does not alter the intestinal phenotypes, of extended CVA or increased bacterial load in BALB CF mice.
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