TRPV1 Activation Promotes β-arrestin2 Interaction with the Ribosomal Biogenesis Machinery in the Nucleolus:Implications for p53 Regulation and Neurite Outgrowth.

Ahmed Hassan,Francina Agosti,Manon Defaye,Antoine Dufour,Robyn Flynn,Daniel Young,Mark G H Scott,Christophe Altier,Mircea Iftinca,Nasser Abdullah

doi:10.3390/ijms22052280

Abstract

Transient receptor potential vanilloids (TRPV1) are non-selective cation channels that sense and transduce inflammatory pain signals. We previously reported that activation of TRPV1 induced the translocation of β-arrestin2 (ARRB2) from the cytoplasm to the nucleus, raising questions about the functional role of ARRB2 in the nucleus. Here, we determined the ARRB2 nuclear signalosome by conducting a quantitative proteomic analysis of the nucleus-sequestered L395Q ARRB2 mutant, compared to the cytosolic wild-type ARRB2 (WT ARRB2), in a heterologous expression system. We identified clusters of proteins that localize to the nucleolus and are involved in ribosomal biogenesis. Accordingly, L395Q ARRB2 or WT ARRB2 after capsaicin treatment were found to co-localize and interact with the nucleolar marker nucleophosmin (NPM1), treacle protein (TCOF1) and RNA polymerase I (POL I). We further investigated the role of nuclear ARRB2 signaling in regulating neuroplasticity. Using neuroblastoma (neuro2a) cells and dorsal root ganglia (DRG) neurons, we found that L395Q ARRB2 mutant increased POL I activity, inhibited the tumor suppressorp53 (p53) level and caused a decrease in the outgrowth of neurites. Together, our results suggest that the activation of TRPV1 promotes the ARRB2-mediated regulation of ribosomal biogenesis in the nucleolus. The ARRB2-TCOF1-p53 checkpoint signaling pathway might be involved in regulating neurite outgrowth associated with pathological pain conditions.

Highlights

IntroductionPain is a distressing sensation caused by harmful stimuli
To rule out any artefact effect of capsaicin and test the intrinsic property of ARRB2 to localize in the nucleolus, we used a mutant of ARRB2 defective of its nuclear export signal (NES), by replacing the Leucine-395 of ARRB2 with a glutamine residue
Using the STRING analysis, we identified TCOF1, nucleolar and coiled-body phosphoprotein (NOLC1), upstream binding transcription factor (UBTF), nucleolar protein 56 (NOP56), NPM1, fibrillarin (FBL) and H/ACA ribonucleoprotein complex subunit DKC1 (DKC1) which are all related to ribosomal biogenesis and mRNA translation (Figure 3B)

Summary

Introduction

Pain is a distressing sensation caused by harmful stimuli. The initiation of pain signals occurs at the periphery where noxious stimuli are detected and transduced by afferent sensory neurons that have cell soma in the dorsal root ganglia (DRG) and project centrally to the central nervous system (CNS). Acute pain is an essential physiological response to alarm against damaging insults to the body’s organs and tissues [1]. No physiological function is known to be associated with chronic forms of pain such as inflammatory and neuropathic pain [2]. The term plasticity refers to the ability of the neuronal circuits to exhibit structural and functional adaptations to the changing physiological stimuli. Plasticity of neural pain circuits is associated with various pathological conditions including nerve injury or cancer, resulting in the transition from acute to chronic pain [3].

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