Plasticity of renin cells in the kidney vasculature

摘要 肾小球细胞释放的肾素通常足以维持血压和液体电解质 平衡然而，如果成年哺乳动物受到威胁稳态的操纵， 沿着肾小动脉的肌细胞沿着经历了一个显著的转变：它们从收缩性转变为 获得合成和释放肾素能力的内分泌表型。一旦体内平衡 重建后，转化的细胞再次成为平滑肌细胞。能够打开和关闭 肾素表型似乎取决于转化细胞的发育历史：平滑肌细胞 从肾素前体下降，并可能保留记忆，以合成肾素时，需要重新获得 体内平衡肾素表型记忆在基因组中的位置，它是如何构建的， 以及当细胞分化或改变生理状态时它是如何被保留或清除的也是未知的。 我们观察到，肾素细胞具有超级增强子（SE），大的基因组调控的动态集群， 这些区域是调节肾素表型再现的强有力的候选者。我们的整体 假设是，肾素表型的分子记忆存在于细胞的染色质状态， 小动脉细胞，并由一组独特的SE介导，这些SE控制肾素细胞的身份， 他们的后代使用体内和体外谱系追踪、基因活性报告、表观基因组编辑 和染色质成像技术，我们建议追求以下相互关联的假设和目标： 目标1。检验以下假设：肾素细胞表型的获得伴随着 建立独特的SE，其强制来自肾素谱系的基因的表达。 目标2.检验肾素SE调节肾素基因表达的假设， 染色质与其他基因的动态相互作用控制着凝乳酶细胞的身份。 了解血管细胞如何适应和转换它们的身份是一个基本的生物学问题， 适用于多种肾脏和肾外疾病。这些知识可能会导致新的目标，以防止 肾素细胞命运的变化，导致威胁心血管、肾脏和造血系统疾病， 来协调多种自我平衡反应通过提供关于 小动脉细胞获得并保持其可塑性的机制，这是一个基本上尚未探索的前沿， 该提案有可能使患有肾脏和血管疾病以及高血压的儿童和成人受益。

Abstract  Release of renin by juxtaglomerular cells usually suffices to maintain blood pressure and fluid-electrolyte balance. However, if an adult mammal is subjected to manipulations that threaten homeostasis, smooth muscle cells along the renal arterioles undergo a remarkable transformation: they switch from a contractile to an endocrine phenotype acquiring the capacity to synthesize and release renin. Once homeostasis is reestablished, the transformed cells become smooth muscle cells again. The ability to switch on and off the renin phenotype seems to depend on the developmental history of the transformed cells: smooth muscle cells descend from renin precursors and may retain the memory to synthesize renin when necessary to regain homeostasis. Where in the genome the memory of the renin phenotype resides, how it is constructed, and how it is retained or erased as the cells differentiate or change physiological status is unknown. We observed that renin cells possess super-enhancers (SEs), dynamic clusters of large genomic regulatory regions that are strong candidates to regulate the reenactment of the renin phenotype. Our overall hypothesis is that the molecular memory of the renin phenotype resides in the chromatin state of the arteriolar cells and is mediated by a distinctive set of SEs that control the identity of renin cells and their descendants. Using in vivo and in vitro lineage tracking, reporters of gene activity, epigenome editing and chromatin imaging techniques, we propose to pursue the following interrelated hypotheses and aims: Aim 1. Test the hypothesis that acquisition of the renin cell phenotype is accompanied by the establishment of unique SEs that enforce the expression of genes from the renin lineage. Aim 2. Test the hypothesis that the renin SE regulates expression of the renin gene and through dynamic chromatin interactions with other genes controls renin cell identity. Understanding how vascular cells adopt and switch their identity is a fundamental biological question with applicability to multiple, renal and extra renal diseases. This knowledge may lead to novel targets to prevent renin cell fate changes that result in threatening cardiovascular, renal and hematopoietic diseases and inability to coordinate multiple homeostatic responses. By providing essential new knowledge regarding the mechanisms whereby arteriolar cells acquire and maintain their plasticity, a frontier basically unexplored, this proposal has the potential to benefit children and adults with kidney and vascular diseases and hypertension.