Intravital imaging of podocyte calcium in glomerular injury and disease
Intravital imaging of podocyte calcium in glomerular injury and disease
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DOI：
10.1172/jci71702
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发表时间：
2014-05-01
影响因子：
15.9
通讯作者：
Peti-Peterdi, Janos
中科院分区：
文献类型：
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作者：
Burford, James L.;Villanueva, Kane;Peti-Peterdi, Janos
细胞内钙（[Ca-2 i]（i））信号传导介导包括肾足细胞在内的多个器官的生理和病理过程;然而，体内足细胞[Ca-2 i]（i）动力学尚未完全了解。在这里，我们开发了一种成像方法，使用多光子显微镜（MPM）直接可视化仅在这些细胞中表达荧光钙指示剂的活小鼠完整肾脏内的足细胞[Ca-2 i]（i）动态。[Ca-2 i]（i）在对照足细胞中处于低稳态水平，而Ang II输注引起轻微升高。实验性局灶性足细胞损伤引发了损伤部位周围足细胞[Ca-2 i]（i）的稳健和持续升高，并促进了沿毛细血管袢的细胞间传播足细胞[Ca-2 i]（i）波沿着传播。嘌呤能[Ca-2 i]（i）信号传导抑制剂以及缺乏P2 Y2嘌呤能受体的动物可改善[Ca-2 i]（i）波传播。足细胞[Ca-2 i]（i）增加导致肾小球丛收缩和毛细血管白蛋白渗透性增加。在肾纤维化和肾小球硬化的临床前模型中，高poclocyte [Ca-2 i]（i）与细胞运动性增加相关。我们的发现提供了肾小球病理学中荚状细胞[Ca-2 i]（i）的体内重要性的直观证明，并表明嘌呤能[Ca-2 i]（i）信号传导是荚状细胞损伤中的一种稳健和关键的致病机制。这种在体成像方法将允许在完整的活体肾脏中进一步详细研究肾小球疾病的分子和细胞机制。
Intracellular calcium ([Ca-2i](i)) signaling mediates physiological and pathological processes in multiple organs, including the renal podocyte; however, in vivo podocyte [Ca-2i](i) dynamics are not fully understood. Here we developed an imaging approach that uses multiphoton microscopy (MPM) to directly visualize podocyte [Ca-2i](i) dynamics within the intact kidneys of live mice expressing a fluorescent calcium indicator only in these cells. [Ca-2i](i) was at a low steady-state level in control podocytes, while Ang II infusion caused a minor elevation. Experimental focal podocyte injury triggered a robust and sustained elevation of podocyte [Ca-2i](i) around the injury site and promoted cell-to-cell propagating podocyte [Ca-2i](i) waves along capillary loops. [Ca-2i](i) wave propagation was ameliorated by inhibitors of purinergic [Ca-2i](i) signaling as well as in animals lacking the P2Y2 purinergic receptor. Increased podocyte [Ca-2i](i) resulted in contraction of the glomerular tuft and increased capillary albumin permeability. In preclinical models of renal fibrosis and glomerulosclerosis, high poclocyte [Ca-2i](i) correlated with increased cell motility. Our fmdings provide a visual demonstration of the in vivo importance of pod.ocyte [Ca-2i](i) in glomerular pathology and suggest that purinergic [Ca-2i](i) signaling is a robust and key pathogenic mechanism in pod.ocyte injury. This in vivo imaging approach will allow future detailed investigation of the molecular and cellular mechanisms of glomerular disease in the intact living kidney.