Exosomal miR-432-5p, miR-4433b-5p and miR-599 as Biomarkers for Monitoring the Severity of Anti-N-methyl-D-aspartate Receptor Encephalitis
Background: The diagnosis and monitoring of Anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis typically rely on clinical manifestations and the detecting of anti-NMDAR antibodies. However, several studies have found that anti-NMDAR IgG in serum is not entirely specific and can be detected in about 3% of healthy individuals. Objective: To identify novel biomarkers that can accurately monitor the severity of anti-NMDAR encephalitis. Methods: We enrolled 9 patients with anti-NMDAR encephalitis and categorized them into an acute-phase group and a stable-phase group based on the duration of illness and disease severity. The clinical severity of the patients was assessed using the modified Rankin Scale (mRS) and the clinical assessment scale for autoimmune encephalitis (CASE). Then, we isolated exosomal miRNAs from plasma samples and analysed the differentially expressed miRNAs through next-generation sequencing. The sequencing results were validated using RT-qPCR. Furthermore, we conducted correlation analyses between miRNAs and clinical severity. Finally, we performed the functional pathways analysis to explore the underlying mechanisms in anti-NMDAR encephalitis. Results: We have found that exosomal miR-432-5p, miR-4433b-5p and miR-599 exhibited significant differences between patients with anti-NMDAR encephalitis and healthy controls, as well as at different stages of the disease. The expressions of miR-432-5p and miR-4433b-5p were negatively correlated with both the mRS and the CASE. We further identified that the pathways involved in rhythmic processes and neuroinflammation, as well as glutamatergic signaling, play significant roles in the pathogenesis of anti-NMDAR encephalitis. Conclusions: Our research indicates that exosomal miR-432-5p, miR-4433b-5p and miR-599 were highly correlated with the severity of anti-NMDAR encephalitis and can serve as potential biomarkers for disease monitoring. We further identified the pathways play significant roles in anti-NMDAR encephalitis. By modulating the functions of these crucial pathways, we can potentially uncover novel therapeutic targets and improve patient outcomes. Overall design: Peripheral blood samples were collected from patients with anti-NMDAR encephalitis and healthy people for the isolation of extracellular vesicles. RNA extraction and miRNA sequencing were performed on extracellular vesicles