Neural control of pancreatic endocrine function in obesity and diabetes

我们的长期目标是通过精确控制胰腺神经活动来治疗糖尿病。我们将创建一个详细和系统的视图定义胰腺神经，他们的基因表达谱，功能和高脂肪饮食（HFD）的影响，这是实现这一目标所必需的。我们的试验数据已经表明，HFD会导致胰腺神经结构的快速破坏，以及它们控制胰岛素释放以响应血糖的能力。我们的建议将通过结合3d成像，RNAseq和神经调节工具（我们在这方面拥有独特和丰富的经验）带来前所未有的精确度和特异性，为胰腺神经控制血糖创造新的见解。如果没有这方面的知识，成功靶向控制糖尿病患者血糖的神经通路的可能性仍然很小。这项提议的总体目标是了解HFD对胰腺副交感神经和交感传出神经的结构、转录组和功能的影响，这是获得治疗糖尿病新途径的下一步。我们的中心假设是HFD增加了胰岛交感神经支配，减少了胰岛副交感神经支配，导致胰岛素不足以维持正常血糖。这项研究的基本原理是胰岛受交感神经和副交感神经的高度支配，而HFD破坏了胰神经的结构、基因表达和功能。然而，我们不知道HFD的结构变化是否均匀，哪些内分泌细胞受到影响或时间过程。我们没有一个全面的基因表达谱，支配胰腺的神经元或HFD破坏的分子途径。此外，我们不知道胰腺副交感神经和交感神经的确切功能，也不知道HFD如何影响这些功能。这些都是我们认识上的重大差距。为了验证我们的中心假设并达到总体目标，我们将a)确定HFD对胰岛交感神经和副交感传出神经三维结构的影响；b)确定HFD对胰腺交感神经和副交感传出神经基因表达的影响；b)确定HFD对胰岛交感神经和副交感神经调节胰岛激素释放功能的影响。为此，我们将使用清除胰腺的3D成像来确定低（10%）或HFD（45%）对喂食和禁食小鼠胰腺副交感神经和交感神经结构的影响及其与β、α和δ细胞的关系。我们将使用单细胞RNAseq来鉴定HFD对胰腺副交感神经和交感神经基因表达的影响以及被HFD破坏的分子通路。我们将使用高度靶向神经调节来确定HFD对胰腺交感神经和副交感神经功能的影响。这些研究将提供对胰腺交感和副交感神经支配独特生物学的全面理解，为未来研究确定关键时期、可逆性和治疗靶点以预防和治疗2型糖尿病奠定重要基础。

Our long-term goal is to enable diabetes treatments through precise control of pancreatic nerve activity. We will create a detailed and systemic view of defined pancreatic nerves, their gene expression profiles, function and the effects of high fat diet (HFD) that are necessary to achieve this. Our pilot data already suggest HFD causes rapid disruption of pancreatic nerve structure and their ability to control insulin release in response to blood glucose. Our proposal will create new insights into pancreatic nerves' control of blood glucose by bringing an unprecedented level of precision and specificity by combining 3d imaging, RNAseq and neuromodulation tools in which we have unique and deep experience. Without this knowledge, the likelihood of successfully targeting neural pathways to control blood glucose in diabetes will remain remote. The overall objective of this proposal, which is the next step toward attaining new avenues to treat diabetes, is to understand the effects of HFD on the structure, transcriptome and function of pancreatic parasympathetic and sympathetic efferent nerves. Our central hypothesis is that HFD increases islet sympathetic innervation and reduces islet parasympathetic innervation leading to insufficient insulin to maintain normal glucose. The rationale that underlies the proposed research is that pancreatic islets are highly innervated by sympathetic and parasympathetic nerves and HFD disrupts pancreatic nerve structure, gene expression and function. However, we do not know if the structural changes from HFD are uniform, which endocrine cells are affected or the time course. We do not have a comprehensive gene expression profile of neurons innervating the pancreas or the molecular pathways disrupted by HFD. In addition, we do not know the precise functions of pancreatic parasympathetic and sympathetic nerves or how HFD affects these roles. These represent major gaps in our understanding. To test our central hypothesis and attain the overall objective, we will a) determine the effects of HFD on the 3D structure of islet sympathetic and parasympathetic efferent nerves, b) determine the effects of HFD on gene expression in pancreatic sympathetic and parasympathetic efferent nerves b) determine the effects of HFD on the function of islet sympathetic and parasympathetic nerves to regulate islet hormone release. To do so, we will use 3D imaging of cleared pancreata to determine the effects of low (10%) or HFD (45%) on pancreatic parasympathetic and sympathetic nerve structure and their relationship with beta, alpha and delta cells in fed and fasted mice. We will use single cell RNAseq to identify the effects of HFD on gene expression and the molecular pathways disrupted by HFD in pancreatic parasympathetic and sympathetic nerves. We will use highly target neuromodulation to determine the effects of HFD on pancreatic sympathetic and parasympathetic nerve function. The proposed studies will provide a comprehensive understanding of the unique biology of pancreatic sympathetic and parasympathetic innervation to form a crucial foundation for future studies identifying critical periods, reversibility and therapeutic targets to prevent and treat type 2 diabetes.