The problem
Pain is pervasive and devastating. Poorly treated chronic pain is the largest source of disability in America with an estimated economic cost of more than 500 billion dollars per year. Moreover, existing strategies to disrupt pain (e.g. opiates) have well known and highly undesirable side effects. Better strategies for preventing chronic pain are desperately needed.
In the vast majority of cases, pain originates in the periphery in a specialized type of sensory neuron called a nociceptor. Long-lived changes in their excitability – which are intimately liked to chronic pain – require de novo protein synthesis. Multiple groups have shown that peripheral inhibition of translation diminishes pain associated behaviors in pre-clinical rodent models. This suggests that post-transcriptional regulation of protein synthesis, likely in nerve fibers, is critical for nociceptive pain.
Our overaching goal is to understand how mRNAs are controlled in nociceptors. To achieve this, we probe fundamental molecular mechanisms that govern pain-associated plasticity in pre-clinical rodent and human iPSC models. This work has already resulted in the identification of new targets and non-opioid strategies that diminish pain-associated behaviors in roedents. Some of our ongoing studies are described below.
mRNA stability & localization
We are interested in probing how mRNA stability, storage, and localization contribute to pain signaling. Despite widespread appreciation for post-transcriptional regulation throughout neurobiology, astonishingly little is known regarding the contributions of these interactions to nociceptive behavioral responses. A major lessor from this work is that RNA-binding proteins feature priminently. Relevant publications:
1. Iglesias P, Lou TF, Bhat V, Megat S, Burton M, Price T, Campbell ZT. Inhibition of Poly(A)- Binding Protein with an RNA mimic reduces pain sensitization in mice. Nature Communications. 2018. 9(1):10. PMC5750225
2. June Bryan de la Peña, Rebecca Chase, Nikesh Kunder, Patrick R Smith, Tzu-Fang Lou, Alexander Stanowick, Prarthana Suresh, Tarjani Shukla, Samuel E Butcher, Theodore Price, Zachary T Campbell. Inhibition of nonsense-mediated decay induces nociceptive sensitization through activation of the integrated stress response. J Neuroscience. 2022. PMID: 36894318
3. Kunder N, de la Peña JB, Lou TF, Chase R, Suresh P, Lawson J, Shukla T, Black BJ, Campbell ZT. The RNA-binding protein HuR is integral to the function of nociceptors in mice and humans. J Neuroscience. 2022. 42(49):9129-9141. PMID36270801
4. Smith PR, Loerch S, Kunder N, Stanowick AD, Lou TF, Campbell ZT. Functionally distinct roles for eEF2K in the control of ribosome availability and p-body abundance. Nature Communications. 2021. 12(1):1-16. PMC8611098
Translation
We are interested in understanding how noxious insults alter translation in nociceptors. We have applied ribosome profiling to this problem extensively. This has led to the identification of targets of local translation in nerve fibers, functional upstream open reading frames, and targets implicated in translation that are required for pain-associated behaviors. Relevant publications:
1. de la Peña JB, Barragan-Iglesias P, Lou TF, Loerch S, Kunder N, Shukla T, Song J, Megat S, Moy JK, Wanghzou A, Ray PR, Hoyt K, Steward O, Price TJ, Shepherd J, Campbell ZT. Intercellular Arc signaling regulates vasodilation. J Neuroscience. 2021. 15;41(37):7712-7726. PMID: 34326146
2. Barragan-Iglesias P, Kunder N, Wanghzou A, Black B, Ray PR, Lou TF, de la Peña JB, Atmaramani R, Shukla T, Pancrazio JJ, Price TJ, Campbell ZT. A peptide encoded within a 5' untranslated region promotes pain sensitization in mice. Pain. 2021. 162(6):1864-1875. PMC8119312
3. de la Peña JB, Kunder N, Lou TZ, Chase R, Stanowick S, Barragan-Iglesias P, Pancrazio JJ, Campbell ZT. A role for translational regulation by S6 kinase and a downstream target in inflammatory pain. British Journal of Pharmacology. 2021 Dec;178(23):4675-4690. PMC9169231
RNA-protein interactions
Recognition of RNA by proteins is the prerequisite for all subsequent regulation. This information can be applied to tailor the specificity of RNA control in human cells. Here are four publications that describe our progress on this broadly significant fundamental problem:
1. Campbell ZT, Valley CT, Wickens M. A protein-RNA specificity code enables targeted activation of an endogenous human transcript. Nature Struct Mol Biol. 2014. (21): 732-738. PMC4125476
2. Zhou Q, Kunder N, De la Paz JA, Lasley AE, Morcos F, and Campbell ZT. Global pairwise RNA interaction landscapes reveal core features of protein recognition. Nature Communications. 2018. 9(1):2511. PMC6023938
3. Bhat VD, McCann KL, Wang Y, Fonseca DR, Shukla T, Alexander J, Qiu C, Wickens M, Lo TW, Hall TT, Campbell ZT. Engineering a conserved RNA regulatory protein repurposes its biological function in vivo. eLife. 2019. 8 e43788. PMC6351103
4. C Qiu, RN Wine, ZT Campbell, TMT Hall. Bipartite interaction sites differentially modulate RNA-binding affinity of a protein complex essential for germline stem cell self-renewal. Nucleic Acids Research 50 (1), 536-548. PMID34908132
Physiology
We are interested in the understanding the role of post-transcriptional gene control in the activity of rodent and human sensory neurons. We make extensive use of multi-electrode arrays (MEAs) to understand how RNA control contributes to the function of nociceptors. Relevant publications:
1. Chase R, de la Peña JB, Smith PR, Lawson J, Lou TF, Stanowick AD, Black BJ, Campbell ZT. Global analyses of mRNA expression in human sensory neurons reveal eIF5A as a conserved target for inflammatory pain. FASEB J. 2022 36(7): e22422. PMID35747924
2. Black JB, Atmaramani R, Kumaraju R, Plagens S, Romero-Ortega M, Dussor G, Price TJ, Campbell ZT, Joseph J Pancrazio. Adult mouse sensory neurons on microelectrode arrays exhibit increased spontaneous and stimulus-evoked activity in the presence of interleukin-6. Journal of Neurophysiology. 2018. 120(3): 1374-1385. PMC6171072
3. Rahul R Atmaramani, Bryan J Black, June Bryan de la Peña, Zachary T Campbell, Joseph J Pancrazio. Conserved expression of Nav1. 7 and Nav1. 8 contribute to the spontaneous and thermally evoked excitability in IL-6 and NGF-sensitized adult dorsal root ganglion neurons in vitro. Bioengineering. 2020. 7(22): 1-44. PMID32429423
4. de la Peña JB, Kunder N, Lou TZ, Chase R, Stanowick S, Barragan-Iglesias P, Pancrazio JJ, Campbell ZT. A role for translational regulation by S6 kinase and a downstream target in inflammatory pain. British Journal of Pharmacology. 2021 Dec;178(23):4675-4690. PMC9169231
More information
For a detailed overview of translational regulation in pain click here
Examples of our published work can be found here