Proteomic analysis of differentially expressed proteins between stenotic and normal colon segment tissues derived from patients with Hirschsprung's disease

Quantitative Proteomics Reveals Association of Neuron Projection Development Genes ARF4, KIF5B, and RAB8A With Hirschsprung Disease

Hirschsprung disease (HSCR) is a heterogeneous group of neurocristopathy characterized by the absence of the enteric ganglia along a variable length of the intestine. Genetic defects play a major role in the pathogenesis of HSCR, whereas family studies of pathogenic variants in all the known genes (loci) only demonstrate incomplete penetrance and variable expressivity for unknown reasons. Here, we applied large-scale, quantitative proteomics of human colon tissues from 21 patients using isobaric tags for relative and absolute quantification. method followed by bioinformatics analysis. Selected findings were confirmed by parallel reaction monitoring verification. At last, the interesting differentially expressed proteins were confirmed by Western blot. A total of 5341 proteins in human colon tissues were identified. Among them, 664 proteins with >1.2-fold difference were identified in six groups: groups A1 and A2 pooled protein from the ganglionic and aganglionic colon of male, long-segment HSCR patients (n = 7); groups B1 and B2 pooled protein from the ganglionic and aganglionic colon of male, short-segment HSCR patients (n = 7); and groups C1 and C2 pooled protein from the ganglionic and aganglionic colon of female, short-segment HSCR patients (n = 7). Based on these analyses, 49 proteins from five pathways were selected for parallel reaction monitoring verification, including ribosome, endocytosis, spliceosome, oxidative phosphorylation, and cell adhesion. The downregulation of three neuron projection development genes ARF4, KIF5B, and RAB8A in the aganglionic part of the colon was verified in 15 paired colon samples using Western blot. The findings of this study will shed new light on the pathogenesis of HSCR and facilitate the development of therapeutic targets.

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Large-scale, quantitative proteomics of human colon tissues from Hirschsprung disease patients.

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Parallel reaction monitoring, Western blotting, and immunohistochemical staining for validation.

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Four pathways related to differentially expressed proteins: ribosome, endocytosis, spliceosome, and axon guidance.

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Downregulation of ARF4, KIF5B, and RAB8A in the aganglionic (stenotic) colon segment.

Comparative proteomic profiles of the normal and aganglionic hindgut in human Hirschsprung disease

BACKGROUND

Hirschsprung disease (HSCR) is the third most common congenital disorder of the gastrointestinal tract. This study aims to elucidate changes in protein expression between the normal and aganglionic hindgut in human HSCR.

METHODS

The biopsies were obtained from the normal and aganglionic hindgut in human HSCR, and the comparative proteomics were analyzed by mass spectrometry (MS)-based two-dimensional gel electrophoresis (2DE).

RESULTS

A total of 932-986 protein spots were identified in each of the gut segments, among which 30 spots had at least an eightfold difference in volume (%). Of the 30 differentially expressed spots, 15 proteins were identified via sequence analysis. Among these 15 proteins, eight were upregulated and seven were downregulated in the aganglionic group. The well-represented classes included biomarkers of enteric ganglions, extracellular matrix proteins, LIM domain proteins, serum proteins, and other pleiotropic proteins. Five proteins were selected and verified by western blotting and real-time PCR, and the results were consistent with the results of 2DE.

CONCLUSION

MS-based 2DE can help to identify pathological relevant proteins in HSCR; it defines an extensive protein catalog of the normal and aganglionic hindgut and may constitute the basis to understand pathophysiological mechanisms related to the HSCR.