Project description:Differential expression of circular RNAs (DEcircRNAs) in the thalamus, a relay station of the orofacial pain transmission pathway, may play an important role in inflammation and inflammatory pain progression in TMJOA and serve as a potential marker for its targeting. In this study, we obtained the expression profile of circRNAs from the thalamus of the rat TMJOA model by high-throughput sequencing to explore the potential role of circRNA in TMJOA inflammation and chronic inflammatory pain progression and their potential as new targeted molecular markers. Additionally, providing new clues to unravel the molecular mechanisms of chronic orofacial pain, providing insights into the potential roles of circRNAs in pain modulation, and paving the way for future research in this area.
Project description:Orofacial inflammation could lead to transcriptional alterations in the trigeminal ganglion (TG). In this study, we performed single-cell RNA-sequencing (scRNA-seq) analysis of mouse TG to identify all cell types and profile transcriptomic alterations of TG cells under inflammatory conditions. A total of 7 types of cells including endothelial cells, fibroblasts, glial cells, granulocytes, lymphocytes, monocyte-macrophages and several subtypes of neurons were identified. In addition, we performed annotation of neuronal subtypes and differential gene expression analysis among TG neurons, identifying several differential genes involved in pain modulation such as Scn10a, Zbtb20 and Runx1. Collectively, our study revealed the heterogeneity of TG cells and diverse neuronal transcriptomic responses to orofacial inflammation, which aids in the development of novel therapeutics for orofacial inflammatory pain.
Project description:Purpose: In this study, we aimed to analyze lncRNA expression in the whole transcriptome of trigeminal ganglia (TG) and spinal trigeminal nucleus caudalis (Sp5C) in a chronic inflammatory TMJ pain mouse model. Chronic inflammatory TMJ pain was induced by intra-TMJ injection of complete Freund's adjuvant (CFA). The lncRNA expression patterns in the whole transcriptome of TG and Sp5C were profiled with RNA sequencing.
Project description:We used RNA sequencing to screen differentially expressed genes (DEGs) in the rostral ventral medulla (RVM) and thalamus of rats during persistent orofacial pain to explore the mechanism of chronic orofacial pain.
Project description:The mechanism of chronic orofacial pain was investigated by examining the interaction between activated microglia, C1q and neurons in RVM of rats with orofacial pain caused by temporomandibular joint injection of CFA. The results demonstrated that the pain threshold in CFA group exhibited a continuous decline, reaching its lowest point on the third day. During the modeling process, administered daily stereotactic injections of ANX-005 and minocycline into the RVM, which resulted in a notable recovery in the rats' pain threshold and a significant increase in C1q/C3 and microglia in RVM of CFA rat. The application of ANX-005 or minocycline resulted in a reduction in the expression of C1q/C3 and microglia. Notably, the expression of excitatory presynaptic membrane markers reduced and the length and density of dendritic spines decreased on neurons in RVM. Additionally, C1q was abundantly localized on excitatory presynaptic membranes and expressed in microglial lysosomes. Treatment with ANX-005 or minocycline resulted in a reduced number of immunofluorescence colocalizations and an elevated dendritic spine density. These findings indicate that initial orofacial pain induced by CFA, microglia in RVM are involved in the pruning of excitatory presynaptic membranes through the complement C1q/C3-CR3 signaling pathway. This process results in a reduction in the proportion of excitatory synapses and a disruption in the physiological balance between RVM descending facilitation and descending inhibition. This leads to the predominance of descending facilitation in pain transmission in the RVM, which in turn facilitates the chronification of orofacial pain.
Project description:Intractable neuropathic pain is recognized as a common symptom of neuromyelitis optica spectrum disorder (NMOSD). However, the underlying mechanism of NMOSD pain remains to be elucidated. Here, we established NMOSD pain model by injecting anti-AQP4 recombinant autoantibodies (AQP4-Ab) generated from NMOSD patient’s plasmablasts into rat spinal cords and confirmed the development of mechanical allodynia. AQP4-Ab mediated extracellular ATP release from astrocytes and pharmacological inhibition of ATP receptor reversed mechanical allodynia in NMOSD pain model. Furthermore, transcriptome analysis revealed microglia activation and IL-1β elevation in NMOSD spinal cord. Inhibition of microglia activation and neutralization of IL-1β also attenuated neuropathic pain in NMOSD rat model. In addition, the human CSF ATP concentration was significantly higher in the acute and remission phase of NMOSD than in multiple sclerosis and other neurological disorder patients. These findings indicate ATP, microglial activation and IL-1β secretion orchestrates the pathogenesis of NMOSD neuropathic pain.
Project description:Neuropathic pain is an apparently spontaneous experience triggered by abnormal physiology of the peripheral or central nervous system, which evolves with time. Neuropathic pain arising from peripheral nerve injury is characterized by a combination of spontaneous pain, hyperalgesia and allodynia. There is no evidence of this type of pain in human infants or rat pups; brachial plexus avulsion, which causes intense neuropathic pain in adults, is not painful when the injury is sustained at birth. Since infants are capable of nociception from before birth and display both acute and chronic inflammatory pain behaviour from an early neonatal age, it appears that the mechanisms underlying neuropathic pain are differentially regulated over a prolonged postnatal period. We used microarrays to detail the global programme of gene expression underlying the differences in nerve injury between along the postnatal development and identified distinct classes of regulated genes during the injury Experiment Overall Design: We have performed a microarray analysis of the rat L4/L5 dorsal root ganglia, 7 days post spared nerve injury, a model of neuropathic pain. Genes that are regulated in adult rats displaying neuropathic behaviour were compared to those regulated in young rats (10 days old) that did not show the same neuropathic behaviour.
Project description:Inflammation plays a role in neuropathic pain conditions as well as in pain induced solely by an inflammatory stimulus. Robust mechanical hyperalgesia and allodynia can be induced by locally inflaming the L5 dorsal root ganglion (DRG) in rat. This model allows investigation of the contribution of inflammation per se to chronic pain conditions. Most previous microarray studies of DRG gene expression have investigated neuropathic pain models involving axon transection. To examine the role of inflammation, we used microarray methods to examine gene expression 3 days after local inflammation of the L5 DRG in rat. We observed significant regulation in a large number of genes (23% of observed transcripts), and examined 221 (3%) with a fold-change of 1.5-fold or more in more detail. Immune-related genes were the largest category in this group and included members of the complement system as well as several pro-inflammatory cytokines. However, these upregulated cytokines had no prior links to peripheral pain in the literature other than through microarray studies, though most had previously described roles in CNS (especially neuroinflammatory conditions) as well as in immune responses. The L5 dorsal root ganglion (DRG) was locally inflamed with zymosan/Incomplete Freund's Adjuvant. DRG were isolated 3 days later. Each sample was RNA extracted from a single DRG. 6 samples from rats with local DRG inflammation were compared with 6 samples from sham-operated rats.
Project description:Six different mouse pain models were studied: (1) tumour-injection model for bone cancer pain; (2) partial sciatic nerve ligation (PSL) for neuropathic pain; (3) mechanical joint loading for osteoarthritis pain; (4) oxaliplatin-induced painful neuropathy for chemotherapy-induced pain; (5) hyperalgesic priming model for chronic muscle pain; and (6) complete Freund’s adjuvant (CFA)-injection for inflammatory pain. Transcriptomic microarray analyses were performed using RNA isolated from dorsal root ganglia.