Project description:Understanding factors that drive development and function of the sympathetic neuron is crucial to development of potential therapies for neuroblastoma. Here, we identify a key cell autonomous role for the LIM homeodomain transcription factor ISL1 for survival, proliferation and differentiation of sympathetic neurons throughout development. Analysis of several Isl1 mutant mouse lines, including one in which Isl1 was specifically ablated in sympathetic neuron (Wnt1-cre;Isl1 f/f) revealed an early requirement for Isl1 within sympathetic neurons for proliferation and surrvial. RNA-seq analyses on sympathetic neurons revealed dysregulation of a number of genes critical for sympathetic neuron development .Our studies demonstrated that ISL1 regulated the peoliferation, surrvial and differentiation.
Project description:Understanding factors that drive development of the sympathetic neuron is crucial to development of potential therapies for neuroblastoma. Here, we identify a key cell autonomous role for the LIM homeodomain transcription factor ISL1 for survival, proliferation and differentiation of sympathetic neurons throughout development. Chromatin immunoprecipitation assays performed utilizing antibody to ISL1 in chromatin extracts from sympathetic neurons demonstrated that ISL1 directly binds genomic regions within several genes critical for sympathetic neuron development and function, including subunits of the Insm1, Lmo1,Tlx3 and Prox1. Our studies represent in vivo ChIP-seq studies for sympathetic neurons which provide a basis for further exploration of factors critical to sympathetic neurons development and function .
Project description:Adrenal chromaffin cells and sympathetic neuron are derived from neural crest precursors and both cell types can give rise to childhood cancer, neuroblastoma. However only limited is known about the mechanism of their development. Better understanding of their transcriptomic profiles during development could gives an insight into the cell fates acquisition as well as the origin of neuroblastoma. Yellow fluorescent protein expressing sympathetic neuroblasts and adrenal chromaffin cells were isolated from E12.5 TH-IRES-Cre;ROSA26-EYFP mouse embryos by fluorescence-activated cell sorting. Transcriptomic profiles of sympathetic neuroblasts and adrenal chromaffin cells from embryonic age (E)12.5 TH-IRES-Cre;ROSA26-EYFP mice were generated by RNA sequencing, in four paired biological replicates.
Project description:Neurons derived from human pluripotent stem cells (hPSCs) are a remarkable tool for modeling human neural development and diseases. However, it remains largely unknown whether the hPSC-derived neurons can be functionally coupled with their target tissues in vitro, which is essential for understanding inter-cellular physiology and further translational studies. Here, we demonstrate that hPSC-derived sympathetic neurons can be obtained from hPSCs and that the resulting neurons form physical and functional connections with cardiac muscle cells. By use of multiple hPSC reporter lines, we recapitulated human autonomic neuron development in vitro, and successfully isolated PHOX2B::eGFP+ neurons exhibiting sympathetic marker expression, electrophysiological properties, and norepinephrine secretion. With pharmacological and optogenetic manipulations, the PHOX2B::eGFP+ neurons controlled the beating rates of cardiomyocytes, and their physical interaction led to neuronal maturation. Our study lays a foundation for the specification of human sympathetic neurons and for the hPSC-based neuronal control of end organs in a dish. Using the four genetic reporter systems (OCT4::eGFP, SOX10::eGFP, ASCL1::eGFP, and PHOX2B::eGFP reporter hESC lines), we were able to purify discrete cell populations at four differentiation stages, recapitulating the sympathoadrenal differentiation process in vitro with purified and defined populations in four specific differentiation stages. We performed transcriptome analysis of OCT4::eGFP+ cells (3 biological replicates, representing undifferentiated hESCs), SOX10::eGFP+ cells (3 biological replicates, multi-potent neural crest), ASCL1::eGFP+ cells (3 biological replicates, putative sympathoadrenal progenitors), and PHOX2B::eGFP+ cells (2 biological replicates, putative sympathetic neuronal precursors).
Project description:The cellular mechanism(s) linking macrophages to norepinephrine (NE)-mediated regulation of thermogenesis has been a topic of debate. Here, we identify sympathetic neuron-associated macrophages (SAMs) as a population of macrophages that mediate clearance of NE via expression of Slc6a2, an NE transporter, and monoamine oxidase A (MAOa), a degradation enzyme. Optogenetic activation of the SNS upregulates NE uptake by SAMs and shifts the SAM profile to a more pro-inflammatory state. NE uptake by SAMs is prevented by genetic depletion of Slc6a2 or inhibition of the transporter. We also found that obesity increases SAM content in the SNS. In two mouse models of obesity, genetic ablation of Slc6a2 in SAMs increases brown adipose tissue (BAT) content, causes browning of white fat, increases thermogenesis and leads to significant and sustained weight loss. We further show that this pathway is conserved as human sympathetic ganglia also contain SAMs and the analogous molecular machinery for NE clearance, thus constituting a potential target for obesity treatment.
Project description:Neurons derived from human pluripotent stem cells (hPSCs) are a remarkable tool for modeling human neural development and diseases. However, it remains largely unknown whether the hPSC-derived neurons can be functionally coupled with their target tissues in vitro, which is essential for understanding inter-cellular physiology and further translational studies. Here, we demonstrate that hPSC-derived sympathetic neurons can be obtained from hPSCs and that the resulting neurons form physical and functional connections with cardiac muscle cells. By use of multiple hPSC reporter lines, we recapitulated human autonomic neuron development in vitro, and successfully isolated PHOX2B::eGFP+ neurons exhibiting sympathetic marker expression, electrophysiological properties, and norepinephrine secretion. With pharmacological and optogenetic manipulations, the PHOX2B::eGFP+ neurons controlled the beating rates of cardiomyocytes, and their physical interaction led to neuronal maturation. Our study lays a foundation for the specification of human sympathetic neurons and for the hPSC-based neuronal control of end organs in a dish.
Project description:Maternal diabetes is a recognized risk factor for both short-term and long-term complications in offspring. Beyond the direct teratogenicity of maternal diabetes, the intrauterine environment can influence offspring cardiovascular health. Abnormalities in the cardiac sympathetic system are implicated in conditions such as sudden infant death syndrome, cardiac arrhythmic death, heart failure, and certain congenital heart defects in children from diabetic pregnancies. However, the mechanisms by which maternal diabetes affect the development of the cardiac sympathetic system and consequently, heightening health risks and predisposing to cardiovascular disease remain poorly understood. In this study, we present a comprehensive analysis of the combined impact of a Hif1a-deficient sympathetic system and the maternal diabetes environment on both heart development and the formation of the cardiac sympathetic system. The synergic negative effect of exposure to maternal diabetes and Hif1a deficiency resulted in the most pronounced deficit in cardiac sympathetic innervation and the development of adrenal medulla. Abnormalities in the cardiac sympathetic system were accompanied by a smaller heart, reduced ventricular wall thickness, dilated subepicardial veins, and coronary arteries in the myocardium, along with anomalies in the branching and connections of the main coronary arteries. Transcriptional profiling by RNA-seq revealed significant transcriptome changes in Hif1a-deficient sympathetic neurons, primarily associated with cell cycle regulation, proliferation, and mitosis, explaining the shrinkage of the sympathetic neuron population. Our data demonstrate that a failure to adequately activate HIF-1α regulatory pathway, particularly in the context of maternal diabetes, may contribute to abnormalities in the cardiac sympathetic system. In conclusion, our findings indicate that the interplay between deficiencies in the cardiac sympathetic system and subtle structural alternations in the vasculature, microvasculature, and myocardium during heart development not only increases the risk of cardiovascular disease but also diminishes the adaptability to the stress associated with the transition to extrauterine life, thus, increasing the risk of neonatal death.
Project description:Alterations in autonomic function are known to occur in cardiac conditions including sudden cardiac death. Cardiac stimulation via sympathetic neurons can potentially trigger arrhythmias. Dissecting direct neural-cardiac interactions at the cellular level is technically challenging and understudied due to the lack of experimental model systems and methodologies. Here we demonstrate the utility of optical interrogation of sympathetic neurons and their effects on macroscopic cardiomyocyte network dynamics to address research targets such as the effects of adrenergic stimulation via the release of neurotransmitters, the effect of neuronal numbers on cardiac wave behaviour and the applicability of optogenetics in mechanistic in vitro studies. We present novel methodologies to study neuron-cardiomyocyte interactions involving optogenetic selective probing and all-optical electrophysiology to measure electrical activity in an automated fashion, illustrating the power and high-throughput capability of such interrogations. We present new findings on how neurons impact cardiac macroscopic wave properties, the links between neuron density and cardiac firing rates as well as the challenges and benefits of macroscopic co-cultures as experimental model systems.
Project description:Sympathetic nerves that innervate lymphoid organs regulate immune development and function by releasing norepinephrine (NE) that is sensed by immune cells via their expression of adrenergic receptors (ARs). Here, we demonstrate that ablation of SNS signaling suppresses tumor immunity, and we dissect the mechanism of such immune suppression. We report that disruption of the SNS in mice removes a critical α-adrenergic signal required for maturation of myeloid cells in normal as well as tumor-bearing mice. In tumor-bearing mice, disruption of the α-adrenergic signal leads to the accumulation of immature myeloid-derived suppressor cells (MDSC) that suppress tumor immunity and promote tumor growth. Furthermore, we show that these SNS-responsive MDSCs drive expansion of regulatory T cells via secretion of the alarmin heterodimer S100A8/A9, thereby compounding their immunosuppressive activity. Our results describe a regulatory framework in which sympathetic tone controls the development of innate and adaptive immune cells and influences their activity in health and disease.