Project description:We performed single-cell RNA-seq (10x Chromium 3' v.3.1) on dissociated single cell suspensions from mouse (C57BL/6) celiac and superior mesenteric sympathetic ganglia to determine transcriptomic cell types. We identified sympathetic neuron types that specifically innervate unique combinations of visceral organs and control physiological functions.
Project description:Dysregulation of glucagon secretion in type 1 diabetes (T1D) involves hypersecretion during postprandial states, but insufficient secretion during hypoglycemia. The sympathetic nervous system regulates glucagon secretion. To investigate islet sympathetic innervation in T1D, sympathetic tyrosine hydroxylase (TH) axons were analyzed in control non-diabetic organ donors, non-diabetic islet autoantibody-positive individuals (AAb), and age-matched persons with T1D. Islet TH axon numbers and density were significantly decreased in AAb compared to T1D with no significant differences observed in exocrine TH axon volume or lengths between groups. TH axons were in close approximation to islet α-cells in T1D individuals with long-standing diabetes. Islet RNA-sequencing and qRT-PCR analyses identified significant alterations in noradrenalin degradation, α-adrenergic signaling, cardiac b-adrenergic signaling, catecholamine biosynthesis, and additional neuropathology pathways. The close approximation of TH axons at islet α-cells supports a model for sympathetic efferent neurons directly regulating glucagon secretion. Sympathetic islet innervation and intrinsic adrenergic signaling pathways could be novel targets for improving glucagon secretion in T1D.
Project description:Regulation of membrane receptors involves management of endocytosis. At the neuromuscular junction, the synapse between skeletal muscle and motoneuron, proper density of the major receptor, the acetylcholine receptor, is of utmost importance for sustaining life in context of mobility. Recent work has revealed innervation of NMJs by sympathetic neurons and destruction of them had morphological and functional consequences, suggesting influence on endocytosis. To investigate the pathways and proteins that are relevant for acetylcholine receptor turnover and affected by sympathetic signaling, proteomes of mouse hindlimb muscles from sympathectomized and saline-treated control muscles were compared. Using proteomic, Western blot, and immunofluorescence analysis in chemically sympathectomized mouse hindlimb muscles, the cause of these consequences were aimed to analyzed. This revealed extensive regulation of the proteome by the sympathetic nervous system and a possible regulatory function of the endo/lysosomal and autophagic pathway by sympathetic neuronal input. This finding might provide a new explanation to the observed benefit of sympathicomimetic treatment in several congenital myasthenic syndromes.
Project description:The sympathetic nervous system innervates peripheral organs to regulate their function and maintain homeostasis, whereas target cells also produce neurotrophic factors to promote sympathetic innervation1,2. The molecular basis of this bi-directional communication is unknown. Here we use thermogenic adipose tissue from mice as a model system to show that T cells, specifically T cells, have a crucial role in promoting sympathetic innervation, at least in part by driving the expression of TGF1 in parenchymal cells via the IL-17 receptor complex (IL-17RC). Ablation of IL-17RC specifically in adipose tissue reduces expression of TGF1 in adipocytes, impairs local sympathetic innervation and causes obesity and other metabolic phenotypes that are consistent with defective thermogenesis; innervation can be fully rescued by restoring TGF1 expression. Ablating cells and the IL-17RC signalling pathway also impairs sympathetic innervation in salivary glands and the lungs. These findings demonstrate coordination between T cells and parenchymal cells to regulate sympathetic innervation.
Project description:The sympathetic nervous system innervates peripheral organs to regulate their function and maintain homeostasis, whereas target cells also produce neurotrophic factors to promote sympathetic innervation. The molecular basis of this bi-directional communication remains to be fully elucidated. We use thermogenic adipose tissue as a model system to show that T cells, specifically gdT cells, play a critical role in promoting sympathetic innervation, at least in part through driving TGFβ1 expression in parenchymal cells via IL-17 Receptor C. Adipose-specific ablation of IL-17 Receptor C reduces TGFβ1 expression in adipocytes, impairs local sympathetic innervation and causes obesity and other metabolic phenotypes consistent with defective thermogenesis; innervation can be fully rescued by restoring TGFβ1 expression. Ablating gdT cells and the IL-17 Receptor C signaling pathway also impairs sympathetic innervation in salivary glands and the lung. These findings demonstrate T cell/parenchymal cell coordination to regulate sympathetic innervation.
Project description:The intestine is a barrier tissue whose epithelium has high intrinsic turnover rate; intestinal stem cells, in response to signals from the niche, self-renew and produce progeny that differentiate to fulfill the continuous demand for new epithelial cells that are continuously shed into the lumen. The intestine is innervated by a dense network of peripheral nerves that controls nutrient absorption, intestinal motility, and visceral pain sensation. However, the roles of neurons in regulating epithelial cell homeostasis or regeneration remain as yet undiscovered. Here we investigate the effects of gut-innervating sympathetic neurons on epithelial cell repair following irradiation (IR)-induced gut injury. We observed that sympathetic innervation density in the gut increases post IR, while chemical sympathetic denervation impairs gut regeneration. Combining single cell RNA-sequencing and in vivo experiments, we discovered that sympathetic neurons regulate gut regeneration through modulation of IL22 production in type 3 innate lymphoid cells (ILC3) downstream of 2-adrenergic receptor signaling. These results define a novel neuroimmune axis important for intestinal regeneration.
Project description:To investigate the upstream mechanism of anti-inflammatory effects of ST36 acupuncture, including regulatory mechanism on T cell proliferation and polarization in peripheral immune organs, and whether peripheral sympathetic innervation in immune organs mediates the autoimmune response modulation by acupuncture.
Project description:The sympathetic nervous system controls a wide spectrum of bodily functions including operation of vessels, cardiac rhythm, and the “flight or fight response”. Sympathetic neurons, which are neural crest-derived, develop in coordination with presynaptic motor nerves extending from the central nervous system (CNS). By using nerve-selective genetic ablations, we revealed that sympathetic ganglia development depends on CNS-derived motor innervation. In the absence of preganglionic motor nerves, trunk sympathetic chain ganglia were fragmented and smaller in size, while cervical ganglia were severely misshapen. Sympathetic neurons were misplaced along sensory fibers and projected towards abnormal paths, in some cases invading the sensory dorsal root ganglia. The misplaced progenitors of sympathoblasts corresponded to the nerve-associated, neural crest-derived Schwann cell precursors (SCPs). Notably, we found that SCPs activate the autonomic marker PHOX2B while migrating along motor nerves towards the region of the dorsal aorta in wildtype embryos, suggesting that SCP differentiate into sympathetic neurons while still nerve-associated in motor-ablated embryos. Ligand-receptor prediction from single cell transcriptomic data coupled with functional studies identified Semaphorin 3A/3F as candidate motor nerve-derived signals influencing neural crest migration along axons. Thus, motor nerves control the placement of sympathoblasts and their subsequent axonal navigation during critical periods of sympathetic chain development.