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: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: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:Temporomandibular joint (TMJ) osteoarthritis (OA) is a highly prevalent disorder affecting patient’s quality of life due to joint pain and dysfunction. A comprehensive understanding of cell type diversity and their dynamics of TMJ along joint degeneration and pain is lacking. Here we established an inflammatory TMJOA mouse model via intra-articular injection of CFA (Complete Freund’s Adjuvant). TMJOA mice exhibited OA and orofacial pain, recapitulating hallmark symptoms in patients. We performed single-cell transcriptomic profiling of TMJ followed by the validation. We revealed cellular diversity, anatomic position, and cell dynamics of TMJ at single cell resolution along the joint degeneration and pain.
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:Temporomandibular joint (TMJ) arthritis is a craniofacial disorder characterized by joint dysfunction and orofacial pain. Despite of its established roles in fluid and immune regulation, lymphatic regulation, and function in TMJ remain unknown. Using genetic report mouse, uDISCO tissue clearing, and 3D volume imaging, we defined lymphatic vessel morphology, structure, anatomic location in adult mouse TMJ. We demonstrate in a mouse model of TMJ osteoarthritis (TMJOA) that arthritis induces inflammatory lymphangiogenesis and leads to impaired synovial lymphatic functions, including decreases in synovial influx and lymph node fluid drainage. To establish the causative link between lymphatic remodeling and TMJOA, we performed lymphatic loss- and gain-of-function studies. Lymphatic deficiency exacerbated cartilage defects, bone loss, synovitis, synovial fibrosis, and pain behaviors in TMJOA mice. Conversely, lymphatic activation via a hydrogel-mediated VEGF-C delivery to TMJ reduced TMJ pain, inflammation, and arthritis-like pathogenesis. Therefore, we defined lymphatic structure in TMJ and found that lymphatic dysfunction drives TMJOA pathogenesis and pain, suggesting its potential as a therapeutic target.