Proteomics Study on the Cerebrospinal Fluid of Patients with Encephalitis

Liu-Lin Xiong; Lu-Lu Xue; Yan-Jun Chen; Ruo-Lan Du; Qian Wang; Song Wen; Lin Zhou; Tao Liu; Ting-Hua Wang; Chang-Yin Yu

doi:10.1021/acsomega.1c00367

Proteomics Study on the Cerebrospinal Fluid of Patients with Encephalitis

ACS Omega. 2021 Jun 17;6(25):16288-16296. doi: 10.1021/acsomega.1c00367. eCollection 2021 Jun 29.

Authors

Liu-Lin Xiong¹, Lu-Lu Xue², Yan-Jun Chen³, Ruo-Lan Du³, Qian Wang⁴, Song Wen¹, Lin Zhou¹, Tao Liu⁴, Ting-Hua Wang³, Chang-Yin Yu⁴

Affiliations

¹ Department of Anesthesiology, Affiliated Hospital of Zunyi Medical University, No. 149 Dalian Road, Huichuan District, Guizhou 550000, China.
² Institute of Neuroscience, Kunming Medical University, Kunming 650031, China.
³ Institute of Neurological Disease, West China Hospital, Sichuan University, No. 88 Keyuan South Road, Chengdu 610041, Sichuan, China.
⁴ Department of Neurology, Affiliated Hospital of Zunyi Medical University, No. 149 Dalian Road, Huichuan District, Guizhou 550000, China.

Abstract

Objective: Label-free quantitative proteomics was applied to analyze differentially expressed proteins (DEPs) in the cerebrospinal fluid (CSF) of patients with encephalitis. The database was used to screen for possible biomarkers in encephalitis, followed by validation and preliminary investigation of the role of some DEPs in the pathogenesis of encephalitis using enzyme-linked immunosorbent assay (ELISA).

Methods: We performed label-free quantitative proteomics on 16 cerebrospinal fluid samples (EM group, encephalitis with mental and behavioral disorders patients, n = 5; NED group, encephalitis without mental and behavioral disorders patients, n = 6; N group, healthy individuals, n = 5). The extracted CSF proteins were examined by mass spectrometry and enzymatic digestion and detected using protein profiling and data analysis. Interproscan was used to perform Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis of the DEPs. ELISA was used to verify the changes in the levels of some DEPs in the CSF.

Results: A total of 941 proteins were found to be significantly differentially expressed, including 250 upregulated DEPs and 691 downregulated DEPs. GO analysis suggested that there were six enriched functions that intersect among the EM, NED, and N groups, including synapse organization, membrane, integral component of membrane, membrane part, G-protein-coupled receptor signaling pathway, and transmembrane signaling receptor activity. KEGG analysis revealed that there were three signaling pathways that intersect among the EM, NED, and N groups, including fructose and mannose metabolism, inositol phosphate metabolism, and Jak-STAT signaling pathway. Furthermore, four downregulated encephalitis-related neurological synapse proteins were identified after screening for differentially expressed proteins, including NRXN3, NFASC, LRRC4B, and NLGN2. The result of ELISA further verified that the expression of NLGN2 and LRRC4B was obviously higher in the NED group than in the N group.

Conclusions: These findings demonstrated that NLGN2 and LRRC4B proteins were upregulated in the NED group and could be potential biomarkers for the diagnosis of encephalitis, but still needs a lot of multiomics studies to be used in clinical.