Inhibition of Nonsense-mediated Decay Causes Hyperalgesic Priming in Mice

Abstract

RNA stability permeates neurobiology. Yet, the contribution of a dominant pathway of RNA metabolism termed nonsense-mediated decay (NMD) to pain is unclear. NMD safeguards against translation of mRNAs that harbor premature termination codons. It also controls the stability of roughly 10% of typical protein-coding mRNAs. NMD hinges on the activity of a conserved kinase designated SMG-1. We sought to determine the role of SMG-1 and NMD in pain. We found that SMG-1 is expressed in sensory neurons throughout the DRG. We identified SMG-1 targets in DRG neurons using high-throughput sequencing. We analyzed multiple features present in mRNA to establish the characteristics of NMD substrates in DRG neurons. The most dominant feature was structural content in the 3’UTR. This implies that factors that bind to structured motifs likely recruit NMD machinery to specific mRNAs. We identify numerous NMD targets linked to pain including components of the integrated stress response such as ATF-4. We found that inhibition of SMG-1 with a small molecule results in hyperalgesic priming in mice. Given that ATF-4 is targeted by NMD, we next asked if priming was due to activation of the integrated stress response. Indeed, a small molecule inhibitor of the integrated stress response called ISRIB prevented priming triggered by inhibition of NMD. Collectively, our results indicate that (i) inhibition of NMD is pro-nociceptive, (ii) priming induced by NMD blockade requires the integrated stress response, (iii) and structure is a defining feature of NMD targets. This work establishes a clear link between NMD and pain-associated behaviors in mice. RNA stability permeates neurobiology. Yet, the contribution of a dominant pathway of RNA metabolism termed nonsense-mediated decay (NMD) to pain is unclear. NMD safeguards against translation of mRNAs that harbor premature termination codons. It also controls the stability of roughly 10% of typical protein-coding mRNAs. NMD hinges on the activity of a conserved kinase designated SMG-1. We sought to determine the role of SMG-1 and NMD in pain. We found that SMG-1 is expressed in sensory neurons throughout the DRG. We identified SMG-1 targets in DRG neurons using high-throughput sequencing. We analyzed multiple features present in mRNA to establish the characteristics of NMD substrates in DRG neurons. The most dominant feature was structural content in the 3’UTR. This implies that factors that bind to structured motifs likely recruit NMD machinery to specific mRNAs. We identify numerous NMD targets linked to pain including components of the integrated stress response such as ATF-4. We found that inhibition of SMG-1 with a small molecule results in hyperalgesic priming in mice. Given that ATF-4 is targeted by NMD, we next asked if priming was due to activation of the integrated stress response. Indeed, a small molecule inhibitor of the integrated stress response called ISRIB prevented priming triggered by inhibition of NMD. Collectively, our results indicate that (i) inhibition of NMD is pro-nociceptive, (ii) priming induced by NMD blockade requires the integrated stress response, (iii) and structure is a defining feature of NMD targets. This work establishes a clear link between NMD and pain-associated behaviors in mice.