Intravital visualization of the primary cilium, tubule flow, and innate immune cells in the kidney utilizing an abdominal window imaging approach.

The renal primary cilium is a small microtubule-based appendage thought to have mechano/chemosensory roles detecting changes in the fluid passing through the nephron. Mutations affecting cilium structure or function of ciliary-localized proteins result in a spectrum of diseases termed ciliopathies, with prevalent phenotypes such as the formation of renal cysts and fibrosis. While many studies have been conducted using fixed kidney sections or live imaging of cells in culture to investigate the cilium, examination in the context of a living murine kidney remains to be conducted. Previously, our lab generated the SSTR3 mouse to study cilium dynamics in vivo and found novel cilium behaviors that occurred following alteration of heart rate, blood pressure, and tubule flow. In this manuscript, we utilize multiple transgenic mouse models and an abdominal window imaging approach to observe primary cilia and tubule flow dynamics, immune cell movement, and renal Ca signaling as it occurs in real time within a live mouse kidney. We present this window method as an approach that can be used in combination with various fluorescently labeled transgenic mice to investigate renal physiology, pathology, and function in vivo in longitudinal studies for as long as 5weeks.