Exogenous stem cell factor improves interstitial cells of Cajal restoration after blockade of c-kit signaling pathway

Abstract

Objective. Interstitial cells of Cajal (ICC) have been endowed with considerable intrinsic plasticity. Blockade of the c-kit signaling pathway results in the shift of ICC towards a smooth muscle-like phenotype. Little is known about stem cell factor (SCF), the ligand of c-kit, and the role it plays in the process of restoration. The aim of this study was to determine whether exogenous SCF can promote ICC replenishment following the blockade of c-kit signaling. Material and methods. Neutralizing anti-c-kit monoclonal antibody (ACK2) was administered to mice for 8 days after birth. Jejunal muscle strips were cultured up to 7 days. Electrical rhythmic changes were monitored and ICC were examined by immunohistochemistry. Expression of c-kit mRNA was detected by reverse transcriptase-polymerase chain reaction, and expression of Kit protein was detected by Western blot. Results. When c-kit receptors were blocked, ICC nearly disappeared from the jejunum accompanied by the loss of electrical slow waves. By day 7, after in vitro culture with SCF (100 ng/ml), the amplitude of muscle strip slow waves was restored to 0.19 ± 0.07 mV (p < 0.05), whereas the frequency recovered to 13.7 ± 3.32/min (p < 0.01). Furthermore, labeling for c-kit⁺ cells in the myenteric plexus increased and c-kit mRNA and protein expression were up-regulated compared to that of non-treatment with SCF. Conclusions. The c-kit signaling pathway, activated by SCF, is the critical pathway associated with the control of ICC survival and proliferation. The restoration of ICC number and jejunal electrical rhythm, resulting from blockade of the c-kit signaling pathway, could be facilitated by local SCF administration.

Key Words::

• c-kit
• gastrointestinal motility
• interstitial cells of Cajal
• stem cell factor

Acknowledgements

This work was supported by a grant from the National Natural Science Foundation of China (NO. 30300156). We would like to thank Reji Babygirija for the kind help of English correction.

Ethics approval: All animal experiments were carried out in full accordance with the Animals Scientific Procedures Act 1986 under Home Office approval.

Contribution: Weidong Tong & Houjun Jia: study concept and design, drafting of the manuscript, and obtained funding, acquisition of data; Lin Zhang: analysis and interpretation of data, and statistical analysis; Chunxue Li: technical and material support; TJ Ridlofi: critical revision of the manuscript for important intellectual content; Baohua Liu: study supervision.

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.