Decreased SCF/c-kit signaling pathway contributes to loss of interstitial cells of Cajal in gallstone disease

Abstract

Cholecystolithiasis is a common disease, and gallbladder dysmotility is considered as a pivotal pathogenesis. Interstitial cells of Cajal (ICCs) serve as pacemakers and mediators of neuromuscular transmission for gastrointestinal motility. Reduction of ICCs has been reported in gallstone diseases. However, there are no reasonable mechanisms for the cholecystolithiasis-associated loss of ICCs in humans. Stem cell factor (SCF) and its ligand c-kit are essential for normal development and survival of ICCs. To date, little is known about the SCF/c-kit signaling pathway in gallstone diseases. The purpose of this study was to investigate the role of the SCF/c-kit signaling pathway in the loss of ICCs in cholecystolithiasis. Data from 18 patients with gallstones and 14 individuals without gallstones were compared. The gallbladder contractility was assessed by measuring the gallbladder ejection fraction (GEF) ultrasonographically. Tissues samples were obtained during surgery, changes of ICC quantities were analyzed by immunohistochemistry, and the mRNA and protein expression of SCF and c-kit were detected by Real-Time PCR and Western-blot analysis. Compared with the controls, the GEF was significantly reduced in the gallstone group, and decreased number of ICCs was present obviously in the gallstone group. Furthermore, the mRNA and protein expression of SCF and c-kit were significantly attenuated in the gallstone group. These data indicate that gallbladder motility may be affected by reduction of ICCs in gallstone disease. Additionally, the decreased of SCF/c-kit signaling pathway play an important role in the loss of ICCs.

Keywords: Gallstone disease; c-kit; gallbladder motility; interstitial cells of Cajal; stem cell factor.

Figure 1

The variation in gallbladder ejection fractions (%) between gallstone group and control group. The 15th-, 30th-, 45th-, 60th-, 75th-, and 90th-minute postprandial GEFs of patients with gallstones were lower that of the controls (P<0.05).

Figure 2

Immunohistochemistry for CD117. Mast cells (yellow arrows) within the muscularis propria. CD117-positive ICCs (red arrows) in the the muscularis propria. The density of CD117 positive ICCs in gallstone group was significantly lower than the control group (P<0.05).

Figure 3

Expression of SCF and c-kit mRNA. Decreased expressions of SCF and c-kit mRNA were demonstrated when compared with the control group. Each bar represents the mean ± SD. #P<0.05; *P<0.05.

Figure 4

Expression of SCF and c-kit protein. A. The protein expression of c-kit and SCF were downregulated in the gallstone disease group compared with the control group. β-actin was used as the internal control. B. quantification of SCF and c-kit protein expression. Each bar represents the mean ± SD. #P<0.05; *P<0.05.