The molecular pathogenesis of achalasia: a paired lower esophageal sphincter muscle and serum 4D label-free proteomic study

Abstract

Background Achalasia is a primary esophageal motility disorder with potential molecular pathogenesis remaining uncertain. This study aimed to identify the differentially expressed proteins and potential pathways among achalasia subtypes and controls to further reveal the molecular pathogenesis of achalasia. Methods Paired lower esophageal sphincter (LES) muscle and serum samples from 24 achalasia patients were collected. We also collected 10 normal serum samples from healthy controls and 10 normal LES muscle samples from esophageal cancer patients. The 4D label-free proteomic analysis was performed to identify the potential proteins and pathways involved in achalasia. Results Analysis of Similarities showed distinct proteomic patterns of serum and muscle samples between achalasia patients and controls (both P < 0.05). Functional enrichment analysis suggested that these differentially expressed proteins were immunity-, infection-, inflammation-, and neurodegeneration-associated. The mfuzz analysis in LES specimens showed that proteins involved in the extracellular matrix–receptor interaction increased sequentially between the control group, type III, type II, and type I achalasia. Only 26 proteins altered in the same directions in serum and muscle samples. Conclusions This first 4D label-free proteomic study of achalasia indicated that there were specific protein alterations in both the serum and muscle of achalasia, involving immunity, inflammation, infection, and neurodegeneration pathways. Distinct protein clusters between types I, II, and III revealed the potential molecular pathways associated with different disease stages. Analysis of proteins changed in both muscle and serum samples highlighted the importance of further studies on LES muscle and revealed potential autoantibodies.

Development and Validation of Serum Markers as Noninvasive Diagnostic Methods for Achalasia

“…In this study, a high-throughput, paired lower esophageal sphincter muscle and serum 4D label-free proteomic study was conducted to systematically screen the proteins that were significantly changed in achalasia ( 14 ). Five molecules with the most significant changes in achalasia were selected to explore their potential diagnostic value.…”

“…To explore the molecular pathogenesis and potential biomarkers of achalasia, the paired lower esophageal sphincter muscle and serum 4D label-free proteomic study was performed in our previous research. Profilin-1, galectin-10, immunoglobulin heavy variable (IGHV) 3–9, vasodilator-stimulated phosphoprotein (VASP), and transgelin-2 were found to be the most significantly increased serum proteins in patients with achalasia ( 14 ). Profilin-1, VASP, and transgelin-2 are all actin-binding proteins ( 15 – 17 ) that can be used to diagnose or predict the prognosis for various diseases, such as Alzheimer disease (AD) ( 18 ), hypertension ( 19 ), and hepatocellular carcinoma ( 20 ).…”