A spinoparabrachial circuit defined by Tacr1 expression drives pain.
Ontology highlight
ABSTRACT:
SUBMITTER: Barik A
PROVIDER: S-EPMC7993995 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Chronic pain is a major health care problem with great social and economic consequences. Although the medial prefrontal cortex (mPFC) and the thalamus have been implicated in regulating pain, whether and how these regions may involve in pain chronification process have remained largely unknown. Here, we show that Foxp2+ neurons in mPFC, which are corticothalamic (CT) neurons representing the major mPFC output to thalamus, are deactivated in chronic inflammatory pain. Interestingly, prolonged, but not short-term, inactivation of the Foxp2+ neurons in mPFC increases the sensitivity to noxious stimulations. Conversely, chemogenetic activation of this neuronal cluster induces robust antinociceptive effects in both naïve mice and mice with chronic inflammatory pain. Furthermore, we found that the mPFC Foxp2+ neurons project to several thalamic relay nuclei and that activation of the mPFC to the parataenial nucleus of thalamus (PTN) circuit relieves pain. Finally, RNA-seq of the mPFC Foxp2+ neurons revealed that many genes related to neuronal activity are dysregulated in mice with chronic inflammatory pain. Collectively, our studies revealed that Foxp2+ neurons in mPFC that project to thalamus play a critical role in somatosensory processing and pain chronification.
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Project description:A genetically defined mPFC-thalamic circuit underlies pain chronicity
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Project description:BACKGROUND:Substance P (SP) is a pain- and inflammation-related neuropeptide which preferentially binds to the neurokinin receptor 1 (NK1 ). SP and NK1 receptors have been implicated in joint pain, inflammation and damage in animal models and human studies of osteoarthritis (OA). The aim of this study was to test if genetic variation at the neurokinin 1 receptor gene (TACR1) is associated with pain in individuals with radiographic knee OA. METHODS:Participants from the Genetics of OA and Lifestyle study were used for the discovery group (n = 1615). Genotype data for six SNPs selected to cover most variation in the TACR1 gene were used to test for an association with symptomatic OA. Replication analysis was performed using data from the Chingford 1000 Women Study, Hertfordshire Cohort Study, Tasmanian Older Adult Cohort Study and the Clearwater OA Study. In total, n = 1715 symptomatic OA and n = 735 asymptomatic OA individuals were analysed. RESULTS:Out of six SNPs tested in the TACR1 gene, one (rs11688000) showed a nominally significant association with a decreased risk of symptomatic OA in the discovery cohort. This was then replicated in four additional cohorts. After adjusting for age, gender, body mass index and radiographic severity, the G (minor) allele at rs11688000 was associated with a decreased risk of symptomatic OA compared to asymptomatic OA cases (p = 9.90 × 10-4 , OR = 0.79 95% 0.68-0.90 after meta-analysis). CONCLUSIONS:This study supports a contribution from the TACR1 gene in human OA pain, supporting further investigation of this gene's function in OA. SIGNIFICANCE:This study contributes to the knowledge of the genetics of painful osteoarthritis, a condition which affects millions of individuals worldwide. Specifically, a contribution from the TACR1 gene to modulating pain sensitivity in osteoarthritis is suggested.
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