Region-Resolved Quantitative Proteome Profiling Reveals Molecular Dynamics Associated With Chronic Pain in the PNS and Spinal Cord

Abstract

To obtain a thorough understanding of chronic pain, large-scale molecular mapping of the pain axis at the protein level is necessary, but has not yet been achieved. We applied quantitative proteome profiling to build a comprehensive protein compendium of three regions of the pain neuraxis in mice: the sciatic nerve (SN), the dorsal root ganglia (DRG), and the spinal cord (SC). Furthermore, extensive bioinformatics analysis enabled us to reveal unique protein subsets which are specifically enriched in the peripheral nervous system (PNS) and SC. The immense value of these datasets for the scientific community is highlighted by validation experiments, where we monitored protein network dynamics during neuropathic pain. Here, we resolved profound region-specific differences and distinct changes of PNS-enriched proteins under pathological conditions. Overall, we provide a unique and validated systems biology proteome resource (summarized in our online database painproteome.em.mpg.de), which facilitates mechanistic insights into somatosensory biology and chronic pain—a prerequisite for the identification of novel therapeutic targets.

Vti1b promotes TRPV1 sensitization during inflammatory pain

“…interactome identified here are part of the chronic pain-regulated lDRG membrane proteome we described recently [6]. Remarkably, the abundance of some TRPV1 binding partners identified here was altered during inflammatory pain (CFA-model, e.g.…”

“…In particular, we looked for proteins involved in exoand endocytotic pathways, which have not yet been functionally investigated in DRG. Among them Vesicle transport through interaction with t-SNAREs homolog 1B, Vti1b, drew specific attention because (i) it is a prominent mediator of endosomal vesicle transport and fusion of lipid bilayers [3,74,85,86], and (ii) we recently reported its mild downregulation (log 2 fold change = -0.158; multiple-testing corrected q-value = 0.005) in the membrane proteome of lDRG during inflammatory pain [6]. We confirmed the results of Thakur and colleagues [106] and found that Vti1b is expressed in approximately 80% of all lDRG neurons.…”

Proteomic Modulation in the Dorsal Spinal Cord Following Spinal Cord Stimulation Therapy in an In Vivo Neuropathic Pain Model

“…Proteomic data from five studies show a combined 538 proteins found to be significantly modulated by the SNI model (4, 5, 28–30) (Supplementary Table S2). Of the 155 proteins found to be significantly affected by SCS therapy, 33 overlap with the 538 proteins identified in literature as affected by the injury model.…”

“…Proteomic studies of the SNI model have shown altered protein expression within the spinal cord (4,5,(28)(29)(30), which was found to have a degree of reversed expression following SCS therapy. Proteins involved in metabolism like cytochrome c oxidase (COX4I2), increased in SNI (5) and decreased by SCS (−20%), or proteins involved in redox pathways like NADH dehydrogenase iron-sulfur protein (NDUFS3), increased in SNI (5) and decreased by SCS (−21%), demonstrate that SCS affects expression of intracellular as well as extracellular proteins. More than 70% of all metabolism related proteins were downregulated following SCS therapy.…”

“…The prevalent shift of protein expression in both neurons and glial cells ultimately leads to central sensitization, causing any non-noxious stimuli within the affected region to be perceived as painful. Previous studies have shown differences in proteomes associated with pain originating from inflammation versus a peripheral injury, such as the spared nerve injury (SNI) model, and with only some overlap in protein expression (4,5). Such sensitivity to differing pain sources implies that the neuron-glia proteome may also be sensitive to variations of therapeutic interventions used to provide analgesia.…”