Transcriptional changes in circulating immune cells of patients with myalgic encephalomyelitis

Background: Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a debilitating condition with a cluster of chronic symptoms including fatigue, musculoskeletal/joint pain and disturbances of multiple organ systems that affects more females than males (6:1 ratio). The causes and mechanisms of ME/CFS are unknown. Diagnosis of ME/CFS is made through a process of ruling out medication effects and the absence of other clinical conditions that could otherwise cause normal fatigue. Objectives: The main objective of this research proposal is to identify novel mechanisms of transcriptional regulation in ME/CFS which will help to better understand ME/CFS pathobiology. Methods: We used RNA-seq to evaluate gene expression and alternative splicing in the peripheral blood mononuclear cells (PBMC) of 20 female ME/CFS patients and 20 matched healthy controls at TO (baseline), T1 (VO2max, exercise challenge) and T2 (4 hours of rest after T1). After alignment using STAR and counting exons, we used DESeq2 to evaluate differences in gene expression and DEXSeq to evaluate differences in splicing. We compared the gene expression and splicing events between individuals with ME/CFS and healthy controls at each time point, as well as differences in responses to the exercise challenge (between time points for the same group). Results of RNA-seq analysis were validated using NanoString technology. Results: An increased abundance of differentially expressed genes related to immune disorders, small GTPase mediated signal transduction, protein binding and nucleotide binding was observed. Additionally, the observed changes in gene expression and alternative splicing between time points (in response to exercise challenge) were smaller in individuals with ME/CFS as compared to healthy controls. Conclusion: Our findings provide novel insights into the molecular changes associated with ME/CFS onset and progression enhancing the current understanding of the pathophysiological mechanisms of the disease.This study was supported by NIH awards 1R1 5NS087604-01 A1 and Presidential Faculty Research and Development Grant from Nova Southeastern University. The study used PBMC samples collected under an award 5R01 AR057853-04.