MYPT1 Down-regulation by Lipopolysaccharide-SIAH1/2 E3 Ligase-Ubiquitin-Proteasomal Degradation Contributes to Colonic Obstruction of Hirschsprung Disease

摘要

MYPT1 was down-regulated by LPS-SIAH1/2 E3 ligase-ubiquitin-proteasomal degradation, leading to colonic obstruction. (A) Western blot showed MYPT1 expression after LPS intraperitoneal injection (n = 4–6) (t test). (B and C) Colonic smooth muscle from C57BL/6 mice was treated with or without LPS (0.1 mg/mL) and MG132 (50 μmol/L) for 24 hours and harvested for detection of constitutive expression of MYPT1, SIAH1, and SIAH2 by immunoblotting analysis (C); lysate was collected for immunoprecipitation with MYPT1, MYPT1-ubiquitin, SIAH2, and SIAH2 (B) (n = 3) (one-way analysis of variance [ANOVA]). (D) Position of feces in the colon of C57BL/6 mice after local treatment with LPS or phosphate-buffered saline. Bars represent the mean values ± standard error of the mean. *P < .05; **P < .01; ***P < .001.