Microscale Proteomic Analysis of the Endolymphatic Sac in Menière’s Disease Patients

OBJECTIVE: Endolymphatic hydrops is the primary pathological feature of Menière's disease (MD). An imbalance between endolymphatic fluid production and absorption due to endolymphatic sac (ES) dysfunction may be the major cause of endolymphatic hydrops. This study aimed to identify and characterize global protein expression of the ES in MD patients using microscale proteomics for the first time. METHODS: Liquid chromatography-tandem mass spectrometry was used to analyze the ES samples from six MD patients and six acoustic neuroma (AN) patients (as control) for microscale proteomics and differentially expressed proteins (DEPs) were screened. RESULTS: A total of 1,213 proteins in the ES were identified. Among them, there were 40 DEPs between the two groups. Of these proteins, 34 were upregulated (e.g., DPT and CHMP1B), and 6 were downregulated (e.g., PLPP3 and SCARB2) in the MD group compared to the AN group. DEPs were significantly enriched in coagulation and complement cascades. CONCLUSION: Microscale proteomics revealed a unique protein expression pattern in the ES of MD patients. Several proteins such as DPT, CHMP1B, and LTA4H may be involved in the pathogenesis of MD.