Macrophages preserve endothelial cell specialization in the adrenal gland to modulate aldosterone secretion and blood pressure (scRNA-Seq)

The adrenal cortex is characterized by a distinct architecture as well as a high density of specialized sinusoidal blood vessels. The preservation of this particular endothelial cell phenotype is likely vital for proper adrenal gland function. The aldosterone-producing zona glomerulosa harbors macrophages in close association with sinusoidal capillaries. However, the function of this macrophage-endothelial cell-juxtaposition in steady-state conditions is unknown. We show that macrophages preserve capillary specialization in the adrenal gland and modulate aldosterone secretion. By combining macrophage-specific deletion of the angiogenic cytokine Vascular Endothelial Growth Factor A (VEGF-A), single-cell transcriptomics and functional phenotyping, we provide evidence that loss of VEGF-A in myeloid cells, including adrenal gland macrophages depletes a specialized subset of PLVAP+ fenestrated endothelial cells in the zona glomerulosa of mice, along with increased deposition of basement membrane collagen IV and induction of sub-endothelial fibrosis. To characterize the impact of macrophage VEGF-A on the adrenal endothelial cell diversity, we isolated CD31+ CD45- endothelial cells from adrenal gland of WT as well as VEGF/LysM female mice at 12 weeks of age and performed single cell transcriptomics.肾上腺皮质（adrenal cortex）具有独特的组织结构，且分布着高密度的特化血窦毛细血管。维持这种特殊的内皮细胞表型，对于肾上腺正常发挥生理功能至关重要。产生醛固酮的肾上腺球状带（zona glomerulosa）中，巨噬细胞与血窦毛细血管紧密毗邻。然而，稳态条件下这种巨噬细胞-内皮细胞毗邻结构的生理功能仍未明确。本研究证实，巨噬细胞可维持肾上腺毛细血管的特化状态，并调控醛固酮的分泌。通过特异性敲除髓系细胞（包括肾上腺巨噬细胞）中的血管生成细胞因子血管内皮生长因子A（Vascular Endothelial Growth Factor A, VEGF-A），结合单细胞转录组学（single-cell transcriptomics）与功能表型分析，我们发现：小鼠肾上腺球状带内的PLVAP阳性有窗内皮细胞亚群，会因髓系细胞VEGF-A的缺失而耗竭，同时伴随基底膜IV型胶原沉积增加以及内皮下纤维化的发生。为了阐明巨噬细胞来源的VEGF-A对肾上腺内皮细胞多样性的影响，我们从12周龄的野生型（WT）以及VEGF/LysM雌性小鼠的肾上腺组织中分离得到CD31阳性、CD45阴性的内皮细胞，并开展了单细胞转录组分析。