Regulation of Pain Genes—Capsaicin vs Resiniferatoxin: Reassessment of Transcriptomic Data

Abstract

Emerging evidence has shown a strong association between neuropathic pain and chronic diseases. In recent years, the treatment of neuropathic pain has attracted more attention. Natural products, such as capsaicin and resiniferatoxin, have been well utilized to treat this disease. In this study, we aim to compare the regulatory effects of capsaicin and resiniferatoxin on pain-related genes as well as on genes with no direct association with pain. Public transcriptomic and microarray data on gene expression in the dorsal root ganglia and genes associated with TRPV1 (+) neurons were obtained from the GEO database and then analyzed. Differentially expressed genes were selected for further functional analysis, including pathway enrichment, protein-protein interaction, and regulatory network analysis. Pain-associated genes were extracted with the reference of two pain gene databases and the effects of these two natural drugs on the painassociated genes were measured. The results of our research indicate that as compared to capsaicin, resiniferatoxin (RTX) regulates more non pain-associated genes and has a negative impact on beneficial genes (off-targets) which are supposed to alleviate nociception and hypersensitivity by themselves. So, based on this study, we may conclude that capsaicin may be less potent when compared to RTX, but it will elicit considerably less adverse effects too. Thereby confirming that capsaicin could be used for the efficient alleviation of neuropathic pain with possibly fewer side effects.

TRPV1 participates in neuropathic pain after spinal cord injury by mediating the proliferation and activation of CX3CL1-positive glial cells in the spinal dorsal horn

“…Moreover, the mechanical hyperalgesia and thermal hyperalgesia of SCI rats were signi cantly alleviated after treatment with the antagonist, manifested by the increase in the pain threshold, which veri ed that the TRPV1 channel is a reliable analgesic target. Regarding the TRPV1 agonists, previous studies have demonstrated that capsaicin induces transient hyperalgesia and local burning sensation at the initial stage of pain, followed by receptor desensitisation through overactivation of TRPV1 channels, resulting in analgesic effects [43,44]. These results suggest that TRPV1 should be considered as a novel therapeutic target for NP, although the mechanism still needs to be further elucidated.…”

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