Differential Expression and Significance of Circulating microRNAs in Cerebrospinal Fluid of Acute Encephalitis Patients Infected with Japanese Encephalitis Virus
Changes in circulating microRNAs (miRNAs) in the cerebrospinal fluid (CSF) have been associated with different neurological diseases. Here, we presented results of a pilot study aimed at determining the feasibility of detecting miRNAs in the CSF of Japanese Encephalitis virus (JEV) infected individuals with acute encephalitis syndrome (AES). We demonstrated the circulating miRNA profile in CSF of acute encephalitis patients infected with JEV. Using a quantitative real-time PCR-based miRNA array, we examined the level of 87 miRNAs expressed in human exosomes isolated from CSF. Subsequently, correlation between cytokine level and miRNAs expression in CSF samples was examined. In this study, we identified and validated the upregulated expression of three miRNAs, miR-21-5p, miR-150-5p, and miR-342-3p that were specifically circulated in CSF of acute encephalitis patients infected with JEV. CSF miR-21-5p, miR-150-5p, and miR-342-3p expressions were also elevated in infected mice brain. However, the expression pattern of these miRNAs differed in neuronal cells, microglial cells, and the exosome derived from JEV-infected cell culture supernatant. Interestingly, neuronal cells infected with vaccine strain (SA-14-14) did not lead to any upregulation of these three miRNAs. Further, miR-150-5p expression was found to be negatively correlated(r = −0.5279, p = 0.016) with TNFα level. Pathway analysis of putative target genes of these miRNAs indicated involvement of TGF-β, NGF, axon guidance, and MAPK signaling pathways in JEV/AES patients. This study for the first time represents the circulating miRNA in CSF of AES patients and identified the upregulated miRNAs in JEV-infected patients and offers the basis for future investigation.
KeywordsExosome Circulating miRNAs Acute encephalitis
This work is supported by the funding from DBT, India (BT/PR6714/MED/29/617/2012) to A. B (Arup Banerjee). We acknowledge Dr. Manpreet Kaur, Vaccine Technologist at VIDRC, THSTI, for assisting in flow cytometric data analysis. We also acknowledge Suman Ghosal and Shaoli Das, Senior Research Fellow at Computational Biology Group, Indian Association for the Cultivation of Science, Kolkata, India for helping in pathway and network analysis. We are also thankful to all the technical staff of Department of Virology, School of Tropical Medicine for collecting and processing the CSF samples.
Compliance with Ethical Standards
CSF samples were collected by diagnostic lumbar puncture after written informed consent and after exclusion of large intracranial mass lesions or increased intracranial pressure or both. The STM ethical committee had approved CSF sample collections. All CSF samples were collected in accordance with the approved guidelines and regulations.
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