Regulation of μ-opioid type 1 receptors by microRNA134 in dorsal root ganglion neurons following peripheral inflammation

MicroRNA-based therapy in pain medicine: Current progress and future prospects

MicroRNAs (miRNAs) are small noncoding RNA molecules of 18-25 nucleotides in length that regulate gene expression involved in fundamental cell processes. The induction and chronification of pain is associated with many expressional changes in pain-related proteins. miRNA has the potential to regulate gene and protein expression associated with the induction and chronification of pain. Thus, miRNAs might have promise in therapy and as a diagnostic and prognostic biomarker in pain medicine. The application of miRNA has been an emerging field in pain research in recent years. Many studies focusing on the regulation of miRNAs under different tissue and nociceptive stimuli have been performed in recent years. In this review, we intend to introduce the most recent research in the field of miRNA related with pain medicine such as the expression and function of miRNA in different animal pain model, the challenge of application and delivery of miRNA in vivo, the potential toxic effects of miRNA and future problems in clinical application that need to be resolved. This review focuses on the results of miRNA in animal studies and the prospect for future success.

microRNAs in nociceptive circuits as predictors of future clinical applications

Neuro-immune alterations in the peripheral and central nervous system play a role in the pathophysiology of chronic pain, and non-coding RNAs - and microRNAs (miRNAs) in particular - regulate both immune and neuronal processes. Specifically, miRNAs control macromolecular complexes in neurons, glia and immune cells and regulate signals used for neuro-immune communication in the pain pathway. Therefore, miRNAs may be hypothesized as critically important master switches modulating chronic pain. In particular, understanding the concerted function of miRNA in the regulation of nociception and endogenous analgesia and defining the importance of miRNAs in the circuitries and cognitive, emotional and behavioral components involved in pain is expected to shed new light on the enigmatic pathophysiology of neuropathic pain, migraine and complex regional pain syndrome. Specific miRNAs may evolve as new druggable molecular targets for pain prevention and relief. Furthermore, predisposing miRNA expression patterns and inter-individual variations and polymorphisms in miRNAs and/or their binding sites may serve as biomarkers for pain and help to predict individual risks for certain types of pain and responsiveness to analgesic drugs. miRNA-based diagnostics are expected to develop into hands-on tools that allow better patient stratification, improved mechanism-based treatment, and targeted prevention strategies for high risk individuals.