A molecular architecture of the vagal interoceptive system
Ontology highlight
ABSTRACT: Interoception, the ability to timely and precisely sense changes inside the body, is critical for survival. Vagal sensory neurons (VSNs) form an important body-to-brain axis, navigating along body’s rostral-caudal axis to their target organs and dive across organ’s surface-lumen axis into appropriate tissue layers to sense stimuli with various physical properties. The brain can discriminate numerous body signals through VSNs, yet the underlying molecular coding strategy remains poorly understood. Here we show that VSNs code visceral organ, tissue layer, and stimulus modality, three key features of an interoceptive signal, in different dimensions. Large-scale single-cell profiling of VSNs from seven major organs, including the lung, heart, stomach, esophagus, duodenum, pancreas, and transverse colon, using multiplexed projection-barcodes reveals a ‘visceral organ’ dimension composed of differentially expressed gene modules coding VSN target organs along body’s rostral-caudal axis. Surprisingly, we discover another ‘tissue layer’ dimension with gene modules coding VSN ending locations along organ’s surface-lumen axis. The three independent feature-coding dimensions together specify many parallel VSN pathways in a combinatorial fashion and facilitate complex VSN projection in the brainstem. Our study thus highlights a novel multidimensional coding architecture of the mammalian vagal interoceptive system for effective signal communication.
Project description:Vagal sensory neurons (VSNs) located in the nodose ganglion provide information, such as stomach stretch or the presence of ingested nutrients, to the caudal medulla via specialized cell types expressing unique marker genes. Here, we leverage VSN marker genes identified in adult mice to determine when specialized vagal subtypes arise developmentally and the trophic factors that shape their growth. Experiments to screen for trophic factor sensitivity revealed that brain derived neurotrophic factor (BDNF) and glial cell derived neurotrophic factor (GDNF) robustly stimulate neurite outgrowth from VSNs in vitro. Perinatally, BDNF was expressed by neurons of the nodose ganglion itself, while GDNF was expressed by intestinal smooth muscle cells. Thus, BDNF may support VSNs locally, whereas GDNF may act as a target-derived trophic factor supporting the growth of processes at distal innervation sites in the gut. Consistent with this, expression of the GDNF receptor was enriched in VSN cell types that project to the gastrointestinal tract. Lastly, mapping of genetic markers in the nodose ganglion demonstrates that defined vagal cell types begin to emerge as early as embryonic day 13, even as VSNs continue to grow to reach gastrointestinal targets. Despite the early onset of expression for some marker genes, expression patterns of many cell type markers appear immature in prenatal life and mature considerably by the end of the first postnatal week. Together, the data support location-specific roles for BDNF and GDNF in stimulating VSN growth, and a prolonged perinatal timeline for VSN maturation in male and female mice.
Project description:The vomeronasal organ of mice consists of two major types of vomeronasal sensory neurons (VSNs) expressing either receptors of the V1R or V2R family. V1R and V2R VSNs form from a common pool of progenitors but have distinct differentiation programs. We analyzed single cell RNA sequencing data of adult VNO and identified differential expression of Notch1 receptor and Dll4 ligand among the neuronal precursors at the VSN dichotomy. We further demonstrated that Notch signaling is required for effective differentiation of V2R+ basal VSNs.
Project description:The ability to generate visceral sensory neurons (VSN) from induced pluripotent stem (iPS) cells may help to gain insights into how the gut-nerve-brain axis is involved in neurological disorders. We established a protocol to differentiate human iPS-cell-derived visceral sensory ganglion organoids (VSGOs). VSGOs exhibit canonical VSN markers, and single-cell RNA sequencing revealed heterogenous molecular signatures and developmental trajectories of VSGOs aligned with native VSN. We integrated VSGOs with human colon organoids on a microfluidic device and applied this axis-on-a-chip model to Alzheimer's disease. Our results suggest that VSN could be a potential mediator for propagating gut-derived amyloid and tau to the brain in an APOE4- and LRP1-dependent manner. Furthermore, our approach was extended to include patient-derived iPS cells, which demonstrated a strong correlation with clinical data.
Project description:The ability to generate visceral sensory neurons (VSN) from induced pluripotent stem (iPS) cells may help to gain insights into how the gut-nerve-brain axis is involved in neurological disorders. We established a protocol to differentiate human iPS-cell-derived visceral sensory ganglion organoids (VSGOs). VSGOs exhibit canonical VSN markers, and single-cell RNA sequencing revealed heterogenous molecular signatures and developmental trajectories of VSGOs aligned with native VSN. We integrated VSGOs with human colon organoids on a microfluidic device and applied this axis-on-a-chip model to Alzheimer's disease. Our results suggest that VSN could be a potential mediator for propagating gut-derived amyloid and tau to the brain in an APOE4- and LRP1-dependent manner. Furthermore, our approach was extended to include patient-derived iPS cells, which demonstrated a strong correlation with clinical data.
Project description:The vomeronasal organ (VNO) of mice contains two main types of vomeronasal sensory neurons (VSNs)- Apical and Basal. Apical VSNs express vomeronasal receptors (VRs) of the V1R family and project to the anterior accessory olfactory bulb (AOB) and VSNs in the basal portions of the epithelium express receptors of the V2R family and project to the posterior portion of the AOB. In the vomeronasal epithelium of mice we found active BMP signaling. By generating Smad4 conditional mutants we disrupted canonical TGF-b/BMP signaling in either maturing basal VSNs or in mature apical and basal VSNs.
Project description:NPCs adhesion affinity along the AP axis is under the control of Wnt/RA molecular networks Caudal NPCs express a high amount of ECM genes compare to rostral-NPCs.
Project description:We analyzed scRNA-seq data in human pluripotent stem cells derived somite formation models. This in vitro system recapitulates some key aspects of somite formation process along rostral-caudal axis
Project description:Sorafenib is associated with cardiac adverse effects, including left ventricular dysfunction. However, the precise mechanism remains unclear. Here, we aimed to establish the genes responsible for this cardiotoxicity using zebrafish. A pigmentless zebrafish line expressing green fluorescent protein in the heart were treated with or without sorafenib. In vivo fluorescent cardiac imaging revealed that the ventricular dimension of the longitudinal axis in zebrafish treated with sorafenib was significantly lower than in those without sorafenib. Transcriptome analysis of zebrafish hearts revealed that expression of stanniocalcin1 (stc1) in zebrafish treated with sorafenib was significantly lower than that without sorafenib treatment. We were able to demonstrate that the ventricular dimension of the longitudinal axis in stc1 morphant was significantly smaller than that of control zebrafish and that forced expression of stc1 normalized the decrease in ventricular diameter in stc1 morphant and zebrafish treated with sorafenib. These data suggest that stc1 is the gene responsible for sorafenib-induced cardiotoxicity. Gene expression regulated by sorafenib in zebrafish at 4 dpf was measured. Four independent experiments were performed for each group.
Project description:Mesodiencephalic dopaminergic (mdDA) neurons critically regulate locomotory behavior and emotion, and dysfunction is associated with psychiatric and neurodegenerative diseases, including Parkinson's Disease (PD). A pathological hallmark of PD is the specific degeneration of Substantia Nigra (SN) neurons, whereas Ventral Tegmental Area (VTA) neurons are relatively unaffected. Differential molecular programming of the developing SN versus VTA may underly this specific vulnerability, and indeed molecularly distinct mdDA subsets have been identified during development. Driven by the hypothesis that the molecular signature of the SN and VTA originates from differential developmental programming and position along the rostral/caudal axis, we performed genome-wide expression profiling of FACS-purified rostral versus caudal mdDA neurons. Here, we present the distinct transcriptomes of these mdDA subsets and demonstrate how, on a genome-wide scale: 1) transcription factor regulation relates to developmental position, 2) rostral and caudal mdDA neurons differ in their functional genome, 3) the molecular signature of rostral versus caudal mdDA neurons relates to the SN versus VTA molecular profile in adult mice and human and 4) human homologues of rostrally enriched genes are mostly downregulated in the SN of PD patients. Our analyses substantiate the relationship of developmental positions with the SN versus VTA distinction in adult, and suggest cross-species conservation of molecular programs. Driven by these observations, we present 69 target genes that are rostral enriched and downregulated in PD, and thus provide new leads for the investigation of both the complex coding of developing mdDA subsets and and the molecular mechanisms underlying subset-specific vulnerability in PD.
Project description:Mesodiencephalic dopaminergic (mdDA) neurons critically regulate locomotory behavior and emotion, and dysfunction is associated with psychiatric and neurodegenerative diseases, including Parkinson's Disease (PD). A pathological hallmark of PD is the specific degeneration of Substantia Nigra (SN) neurons, whereas Ventral Tegmental Area (VTA) neurons are relatively unaffected. Differential molecular programming of the developing SN versus VTA may underly this specific vulnerability, and indeed molecularly distinct mdDA subsets have been identified during development. Driven by the hypothesis that the molecular signature of the SN and VTA originates from differential developmental programming and position along the rostral/caudal axis, we performed genome-wide expression profiling of FACS-purified rostral versus caudal mdDA neurons. Here, we present the distinct transcriptomes of these mdDA subsets and demonstrate how, on a genome-wide scale: 1) transcription factor regulation relates to developmental position, 2) rostral and caudal mdDA neurons differ in their functional genome, 3) the molecular signature of rostral versus caudal mdDA neurons relates to the SN versus VTA molecular profile in adult mice and human and 4) human homologues of rostrally enriched genes are mostly downregulated in the SN of PD patients. Our analyses substantiate the relationship of developmental positions with the SN versus VTA distinction in adult, and suggest cross-species conservation of molecular programs. Driven by these observations, we present 69 target genes that are rostral enriched and downregulated in PD, and thus provide new leads for the investigation of both the complex coding of developing mdDA subsets and and the molecular mechanisms underlying subset-specific vulnerability in PD.