Basic Study
Copyright ©The Author(s) 2015. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Jun 21, 2015; 21(23): 7172-7180
Published online Jun 21, 2015. doi: 10.3748/wjg.v21.i23.7172
Abundance and significance of neuroligin-1 and glutamate in Hirschsprung’s disease
Jian Wang, Hao Du, Ya-Ru Mou, Jian-Yi Niu, Wen-Tong Zhang, Hong-Chao Yang, Ai-Wu Li
Jian Wang, Wen-Tong Zhang, Hong-Chao Yang, Ai-Wu Li, Department of Pediatric Surgery, Qilu Hospital, Shandong University, Jinan 250012, Shandong Province, China
Hao Du, Shandong University School of Medicine, Jinan 250012, Shandong Province, China
Ya-Ru Mou, Department of Cardiology, Provincial Hospital Affiliated to Shandong University, Jinan 250012, Shandong Province, China
Jian-Yi Niu, Department of Neurology, Qingzhou Clinical School, Weifang Medical College, Weifang 262500, Shandong Province, China
Author contributions: Wang J and Du H contributed equally to this work and should be considered co-first authors; Li AW, Wang J, Du H, Mou YR, Zhang WT and Yang HC designed the research; Wang J, Du H and Yang HC performed the research; Mou YR and Niu JY contributed new reagents/analytic tools; Mou YR and Zhang WT analyzed the data; and Wang J and Du H wrote the paper.
Supported by National Natural Science Foundation of China, No. 81270720 and No. 81471487.
Ethics approval: The study was reviewed and approved by the Institution Review Board of Qilu Hospital, Shandong University (No. 12015).
Conflict-of-interest: The authors have no conflicts of interest to disclose.
Data sharing: Technical appendix, statistical code, and dataset available from the corresponding author at zisetianxie@163.com. Participants gave informed consent for data sharing. No additional data are available.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Ai-Wu Li, PhD, Department of Pediatric Surgery, Qilu Hospital, Shandong University, No. 107 Wenhuaxi Road, Jinan 250012, Shandong Province, China. zisetianxie@163.com
Telephone: 86-531-82166741
Received: December 29, 2014
Peer-review started: December 29, 2014
First decision: January 22, 2015
Revised: February 20, 2015
Accepted: April 9, 2015
Article in press: April 9, 2015
Published online: June 21, 2015
Processing time: 173 Days and 8.4 Hours
Abstract

AIM: To investigate the abundance and potential diagnostic significance of neuroligin-1 and glutamate (Glu) in Hirschsprung’s disease (HSCR).

METHODS: Ninety children with HSCR and 50 children without HSCR matched for similar nutritional status, age and basal metabolic index were studied. The expression and localization of neuroligin-1 and Glu were assessed using double-labeling immunofluorescence staining of longitudinal muscles with adherent myenteric plexus from the surgically excised colon of children with HSCR. Western blot analysis, quantitative real-time PCR (qRT-PCR) and immunohistochemistry were performed to evaluate the abundance of neuroligin-1 and Glu in different HSCR-affected segments (ganglionic, transitional, and aganglionic segments). Enzyme-linked immunosorbent assay (ELISA) was used to detect and compare serum Glu levels in the long-segment HSCR, short-segment HSCR and non-HSCR samples.

RESULTS: Neuroligin-1 and Glu were co-expressed highest to lowest in the ganglionic, transitional and aganglionic segments based on Western blot (neuroligin-1: 0.177 ± 0.008 vs 0.101 ± 0.006, 0.177 ± 0.008 vs 0.035 ± 0.005, and 0.101 ± 0.006 vs 0.035 ± 0.005, P < 0.005; Glu: 0.198 ± 0.006 vs 0.115 ± 0.008, 0.198 ± 0.006 vs 0.040 ± 0.003, and 0.115 ± 0.008 vs 0.040 ± 0.003, P < 0.005) and qRT-PCR (neuroligin-1: 9.58 × 10-5± 9.94 × 10-6vs 2.49 × 10-5± 1.38 × 10-6, 9.58 × 10-5± 9.94 × 10-6vs 7.17 × 10-6 ± 1.12 × 10-6, and 2.49 × 10-5± 1.38 × 10-6vs 7.17 × 10-6± 1.12 × 10-6, P < 0.005). Serum Glu level was the highest to lowest in the non-HSCR, short-type HSCR and long-type HSCR samples based on ELISA (in nmol/μL, 0.93 ± 0.31 vs 0.57 ± 0.25, 0.93 ± 0.31 vs 0.23 ± 0.16, and 0.57 ± 0.25 vs 0.23 ± 0.16, P < 0.005).

CONCLUSION: Neuroligin-1 and Glu may represent new markers of ganglion cells, whose expression may correlate with the pathogenesis, diagnosis, differential diagnosis or classification of HSCR.

Keywords: Neuroligin-1; Hirschsprung’s disease; Glutamate; Ganglion cells; Pathogenesis

Core tip: Based on our results derived from a large set of clinical samples and various experimental methods, neuroligin-1 and glutamate (Glu) were first shown to be co-expressed in ganglion cells; thus neuroligin-1 and Glu may serve as new markers of this cell type, especially for excitatory synapses in the enteric nervous system. Moreover, the decreased abundance of neuroligin-1 and Glu in aganglionic segments may correlate with excessive intestinal contraction because of abnormal excitatory signaling that may ultimately result in Hirschsprung’s disease (HSCR). The serum Glu concentration may serve as a valuable adjunct measure for establishing a diagnosis and classification of HSCR.