Nucleoside-Analog Reverse-Transcriptase Inhibitors (NRTIs) Against Multiple Sclerosis: Comprehensive Review on a Possible Novel Therapeutic Approach.

To this day, the etiology of multiple sclerosis has yet to be fully comprehended by the scientific community. However, the knowledge on mechanisms leading to the development of this neurodegenerative autoimmune disorder increases daily, along with the development of new disease-modifying treatments. A correlation between Epstein-Barr Virus infection and the disease incidence has recently shed light on possible innovative antiviral therapies. Here, we review the literature on Human Endogenous Retroviral sequences as emerging actors for the impairment of remyelination as a major challenge in disease progression. Our primary focus is the HERV-W envelope protein, which has been found at elevated levels in individuals affected by this condition and is suggested here as a potential therapeutic target. We then continue analyzing the clinical cases where antiretroviral drugs have been tested to treat multiple sclerosis patients and, from successes and failures, we finally narrow down our therapeutic hypothesis to the administration of Nucleoside-analog Reverse Transcriptase Inhibitors to target the HERV-W envelope protein, possibly leading to remyelination and significantly improving the condition of those affected by the disease. The main purpose of this review is to present a rationale for the therapeutic potential of this drug class and offer a new perspective for therapeutic options against multiple sclerosis.