Project description:The trigeminal ganglion is a critical structure in the peripheral nervous system, responsible for transmitting sensations of touch, pain, and temperature from craniofacial regions to the brain. Trigeminal ganglion development depends upon intrinsic cellular programming as well as extrinsic signals exchanged by diverse cell populations. With its complex anatomy and dual cellular origin from cranial placodes and neural crest cells, the trigeminal ganglion offers a rich context for examining diverse biological processes, including cell migration, fate determination, adhesion, and axon guidance. Avian models have, so far, enabled key insights into craniofacial and peripheral nervous system development. Yet, the molecular mechanisms driving trigeminal ganglion formation and subsequent nerve growth remain elusive. In this study, we performed RNA-sequencing at multiple stages of chick trigeminal ganglion development and generated a novel transcriptomic dataset that has been curated to illustrate temporally dynamic gene expression patterns. This publicly available resource identifies major pathways involved in trigeminal gangliogenesis, particularly with respect to the condensation and maturation of placode-derived neurons, thus inviting new lines of research into the essential processes governing trigeminal ganglion development.
Project description:Nogo-A is a major regulator of neural development and regeneration in the central nervous system, but its role in tooth innervation remains largely unknown. Neurons of the trigeminal ganglion innervate the teeth. We showed that Nogo-A is expressed in the trigeminal ganglion and tooth-related nerve fibres. Nogo-A deletion in mice leads to a less complex neuronal network when compared to wild-type animals. Bulk RNA sequencing on the trigeminal ganglia of Nogo-A KO and wild-type mice revealed gene expression changes associated with alterations in neurotrophin signalling and neuronal synaptic formation during the development and maturation of the trigeminal neurons.
Project description:Exosomes derived from rat trigeminal ganglion neurons (TGN) were harvested as control group. Exosomes derived from TGN after internalizing exosomes derived from stem cells from human exfoliated deciduous teeth (S-Exo) were harvested as treatment group.
Project description:The sensitization of trigeminal ganglion neurons contributes to primary headache disorders such as migraine, but the specific neuronal and non-neuronal trigeminal subtypes involved remain unclear. We thus developed a cell atlas in which human and mouse trigeminal ganglia are transcriptionally and epigenomically profiled at single-cell resolution. These data describe evolutionarily conserved and human-specific gene expression patterns within each trigeminal ganglion cell type, as well as the transcription factors and gene regulatory elements that contribute to cell-type-specific gene expression. We then leverage these data to identify trigeminal ganglion cell types that are implicated both by human genetic variation associated with migraine and two mouse models of headache. This trigeminal ganglion cell atlas improves our understanding of the cell types, genes, and epigenomic features involved in headache pathophysiology and establishes a rich resource of cell-type-specific molecular features to guide the development of more selective treatments for headache and facial pain.
Project description:Mice lacking the POU-domain transcription factor Brn3a exhibit marked defects in sensory axon growth and abnormal sensory apoptosis. We have determined the regulatory targets of Brn3a in the developing trigeminal ganglion using microarray analysis of Brn3a mutant mice. These results show that Brn3 mediates the coordinated expression of neurotransmitter systems, ion channels, structural components of axons and inter- and intracellular signaling systems. Loss of Brn3a also results in the ectopic expression of transcription factors normally detected in earlier developmental stages and in other areas of the nervous system. Target gene expression is normal in heterozygous mice, consistent with prior work showing that autoregulation by Brn3a results in gene dosage compensation. Detailed examination of the expression of several of these downstream genes reveals that the regulatory role of Brn3a in the trigeminal ganglion appears to be conserved in more posterior sensory ganglia but not in the CNS neurons that express this factor. Experiment Overall Design: Microarrays used to compare the patterns of gene expression in the trigeminal ganglia of Brn3a knockout and wild-type mice. Embryonic day 13.5 (E13.5) was chosen because at this point in development mutant mice exhibit major defects in sensory axon growth, but have yet to undergo the period of extensive sensory neuron death associated with later stages.
Project description:Purpose: The cellular composition of the trigeminal ganglion is altered in the mouse model of 22q11.2 deletion syndrome (the LgDel mouse). The goal of this study is to use RNA-seq to identify transcriptional differences in the embryonic day 10.5 trigeminal ganglion that prefigure changes in mature cell identity in this cranial nerve ganglion. Methods: Trigeminal ganglion mRNA profiles of E10.5 trigeminal ganglia from WT and LgDel mice were generated by deep sequencing. Ganglia samples were prepared as pools of at least 6 ganglia each, from at least 3 embryos. 5 biological replicates of LgDel and WT pools were sequenced. Paired-end libraries were constructed according to the Illumina protocol for the HiSeq2000 platform. Each pooled CNgV RNA sample, defined as a single biological replicate, was fragmented prior to cDNA conversion to ensure transcript coverage. WT (n = 5 replicates) and LgDel (n = 5 replicates) were subjected to sequencing (~100 million paired-end reads/replicate, 100 bp read length) on the Illumina HiSeq2000 platform. Quality-filtered reads were aligned against the mouse reference genome (GRCm38/mm10) using HISAT2 (v.2.1.0). These alignments were indexed using SAMtools (v.1.4) and aligned reads assembled into transcripts using Cufflinks (v.2.2.1) (58). Differential expression analysis was performed using Cufflinks. Validation of key transcriptional differences was performed by SYBR Green qPCR. Results: For WT RNA-Seq, 111–123 million paired-end reads were generated after QC filtering, and 97.3–97.9% of the reads aligned to the mouse genome reference sequence. For LgDel RNA-Seq, 77–137 million paired-end reads were generated after QC filtering, and 94.3–97.8% of the reads aligned to the mouse genome reference sequence. LgDel versus wild-type (WT) CNgV transcriptomes differ significantly at E10.5 just after the ganglion has coalesced. Some changes parallel altered proportions of cranial placode versus cranial neural crest-derived CNgV cells. Others are consistent with a shift in anterior–posterior patterning associated with divergent LgDel cranial nerve differentiation. The most robust quantitative distinction, however, is statistically verifiable increased variability of expression levels for most of the over 17 000 genes expressed in common in LgDel versus WT CNgV. Conclusions: Quantitative expression changes of functionally relevant genes and increased stochastic variation across the entire CNgV transcriptome at the onset of CN V differentiation prefigure subsequent disruption of cranial nerve differentiation and oropharyngeal function in LgDel mice.