miR-142-3p as Potential Biomarker of Synaptopathy in MS

Inflammatory synaptopathy is a prominent pathogenic mechanism in multiple sclerosis (MS) and in its mouse model, which can cause excitotoxic damage by long-lasting excessive synaptic excitation and, consequentially, drives disease progression by leading to motor and cognitive deficits. As synaptopathy occurs early during the disease course and is potentially reversible, it represents an appealing therapeutic target in MS. Although reliable biomarkers of MS synaptopathy are still missing, recent researches highlighted miR-142-3p as a possible candidate. Indeed, miR-142-3p has been described to promote the IL-1beta-dependent synaptopathy by downregulating GLAST/EAAT1, a crucial glial transporter involved in glutamate homeostasis. Furthermore, mir-142-3p has been suggested as a putative negative MS prognostic factor and a target of current MS disease modifying therapies. The hypothesis of this study is that miR-142-3p represents a good biomarker for excitotoxic synaptopathy to predict MS course, and, possibly, treatment efficacy at individual level, including both pharmacological strategies and non-pharmacological interventions, like therapeutic transcranial magnetic stimulation (TMS) to ameliorate MS spasticity. To this aim, the role of miR-142-3p in MS synaptopathy, its potential impact on the efficacy of disease-modifying treatments currently used in MS therapy as well as the influence of genetic variants (SNPs) of miR-142-3p and GLAST/EAAT1 coding genes on the responsiveness to therapeutic TMS, will be further investigated in the study. By validating miR-142-3p as potential biomarker of synaptopathy, it is expect to improve MS prognosis and personalized therapies. Patients with MS, who will undergo neurological assessment, conventional brain MRI scan, and CSF and blood withdrawal for diagnostic and clinical reasons at the Neurology Unit of IRCCS INM-Neuromed will be enrolled in the study. Neurophysiological, biochemical and genetic parameters together with lower limb spasticity will be evaluated. Subjects, who will undergo blood sampling and/or lumbar puncture for clinical suspicions, later on not confirmed, will be recruited as control group. A subgroup of MS patients showing lower limb spasticity will be included in a two-week repetitive TMS stimulation protocol (iTBS) to correlate the patient responsiveness to this non-pharmacological treatment with MS-significant SNPs of both miR-142-3p and GLAST/EAAT1 coding genes.