Transcriptome of neonatal preBötzinger Complex neurons in Dbx1 reporter mice
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ABSTRACT: We sequenced the transcriptome of brainstem interneurons in the specialized respiratory rhythmogenic site dubbed preBötzinger Complex (preBötC) from newborn mice. To distinguish molecular characteristics of the core oscillator we compared preBötC neurons derived from Dbx1-expressing progenitors that are respiratory rhythmogenic to neighbouring non-Dbx1-derived neurons, which support other respiratory and non-respiratory functions.
Project description:GABAergic interneurons play crucial roles in the regulation of neural circuit activity in the cerebral cortex. A hallmark of cortical interneurons is their remarkable structural and functional diversity, yet the molecular determinants and the precise timing underlying their diversification remain largely unknown. Here we use single-cell transcriptomics to identify distinct types of progenitor cells and newborn neurons in the ganglionic eminences, the embryonic proliferative regions that give rise to cortical interneurons. These embryonic precursors define temporally and spatially restricted transcriptional trajectories that unambiguously relate to specific classes of interneurons in the adult cerebral cortex. Our findings therefore suggest that interneuron diversity is already patent shortly after neurons become postmitotic through the acquisition of specific transcriptional programs that unfold over several weeks in the developing cortex
Project description:The respiratory rhythm is generated by the preBötzinger complex in the medulla oblongata, and is modulated by neurons in the retrotrapezoid nucleus (RTN), which are essential for accelerating respiration in response to high CO2. Here we identify a LBX1 frameshift (LBX1FS) mutation in patients with congenital central hypoventilation. The mutation alters the C-terminal but not the DNA-binding domain of LBX1. Mice with the analogous mutation recapitulate the breathing deficits found in humans. Furthermore, the mutation only interferes with a small subset of Lbx1 functions, and in particular with development of RTN neurons that coexpress Lbx1 and Phox2b. Genome-wide analyses in a cell culture model show that Lbx1FS and wild-type Lbx1 proteins are mostly bound to similar sites, but that Lbx1FS is unable to cooperate with Phox2b. Thus, our analyses on Lbx1FS (dys)function reveals an unusual pathomechanism; that is, a mutation that selectively interferes with the ability of Lbx1 to cooperate with Phox2b, and thus impairs the development of a small subpopulation of neurons essential for respiratory control.
Project description:The respiratory rhythm is generated by the preBötzinger complex in the medulla oblongata, and is modulated by neurons in the retrotrapezoid nucleus (RTN), which are essential for accelerating respiration in response to high CO2. Here we identify a LBX1 frameshift (LBX1FS) mutation in patients with congenital central hypoventilation. The mutation alters the C-terminal but not the DNA-binding domain of LBX1. Mice with the analogous mutation recapitulate the breathing deficits found in humans. Furthermore, the mutation only interferes with a small subset of Lbx1 functions, and in particular with development of RTN neurons that coexpress Lbx1 and Phox2b. Genome-wide analyses in a cell culture model show that Lbx1FS and wild-type Lbx1 proteins are mostly bound to similar sites, but that Lbx1FS is unable to cooperate with Phox2b. Thus, our analyses on Lbx1FS (dys)function reveals an unusual pathomechanism; that is, a mutation that selectively interferes with the ability of Lbx1 to cooperate with Phox2b, and thus impairs the development of a small subpopulation of neurons essential for respiratory control.
Project description:Inspiratory breathing movements depend on neurons in the preBötzinger complex (preBötC). We use the Patch-Seq technique and next-generation sequencing to measure the transcriptomes of preBötC insporatory neurons. The preBötC inspiratory neurons can generate both, the rhythm and the rudimentary motor output pattern for inspiratory breathing. We used electrophysiological properties of preBötC inspiratory neurons to categorize them as putative rhythm- and pattern-generators and then aspirated their cellular contents for scRNa sequencing.
Project description:A parafacial region of the medulla called the retrotrapezoid nucleus (RTN) is an important respiratory control center. A group of glutamatergic neurons in this region function as respiratory chemoreceptors by regulating breathing in response to changes in tissue CO2/H+. Cellular mechanisms underlying this function involve H+-inhibition of TASK2 channels and -activation of GPR4 receptors. Evidence also suggests the RTN and greater parafacial region functions as a CO2/H+ sensing network where CO2/H+-activated and -inhibited neurons talk to each other through excitatory and inhibitory interactions. However, contributions of parafacial inhibitory neurons to control of breathing are unknown, and synaptic properties of RTN chemorecpetors have not been characterized. Here, we show the ventral parafacial region contains parvalbumin (Pvalb), cholecystokinin (CCK), neuron-derived neurotrophic factor (Ndnf) and somatostatin (SST) subtypes of interneurons including a subset strongly inhibited by CO2/H+. We also show that chemosensitive RTN neurons receive tonic inhibitory input under control conditions that is withdrawn in a CO2/H+-dependent manner, and chemogenetic inhibition of ventral parafacial inhibitory neurons increases baseline respiratory activity. These results suggest ventral parafacial inhibitory neurons are important determinants of respiratory activity under baseline conditions when the respiratory system is most prone to failure.
Project description:The anatomical relationship of the brainstem is complex, which is the center of respiratory circulation in the human body. We used single cell RNA sequencing (scRNA-seq) to analyze the cellular molecular diversity of the fetal brainstem.
Project description:Transcriptional diversity of mouse olivocochlear neurons (OCNs) was examined using single-nucleus sequencing of brainstem cholinergic neurons at P1, P5, and P26-P28. This dataset includes multiple brainstem cell types, including OCNs and several other populations of cranial motor neurons.
Project description:Inspiratory breathing movements depend on neurons in the preBötzinger complex (preBötC) whose progenitors express the transcription factor Dbx1 (henceforth Dbx1 neurons). We use the Patch-Seq technique and next-generation sequencing to measure the transcriptomes of Dbx1 preBötC neurons. The Dbx1 preBötC neurons can generate both, the rhythm and the rudimentary motor output pattern for inspiratory breathing. We used electrophysiological properties of Dbx1 preBötC neurons to categorize them as putative rhythm- and pattern-generators and then aspirated their cellular contents for scRNA sequencing.