Fig. 7: Intravital confocal microscopy demonstrates murine IC phagocytosis of UPEC in real time.

A single renal connecting and/or collecting tubule of a “IC reporter” mouse was perfused with GFP expressing UPEC and imaged during confocal intravital microscopy. a An example of the imaging with tdT expressing ICs (red) (arrows), the needle tip (asterisk) and GFP expressing UPEC (green) (arrows) flowing through a tubular lumen are presented. Approximately, 1 min after the UPEC injection into the tubule, target tdT+ ICs were identified and imaging was started with the 0 (b), 2 (c), 6.5 (d), and 8.4 (e) min time points presented. b, c UPEC (arrows) can be seen adhering to the lumen of IC (arrowheads) at early time points (d). At the 6.5 min time point, ICs have luminal UPEC aggregates (arrow) and punctate areas of yellow (arrowheads) consistent with internalization of the green UPEC into the red ICs. e At the 8.4 min time point, more UPEC uptake takes place in some ICs (star) compared to other ICs (arrowhead), while tubule areas with no tdT expression (pound sign) (presumed principal cells) have little-to-no green UPEC uptake. UPEC aggregates remain around the luminal IC surface (arrow). a–e Magnification 20×, with digital zoom. Each image is from the same tubule and imaging plane, but at a different time point. Because of breathing-induced cell movement, cellular morphology and position varied from image to image. Images are representative of intravital experiments on two individual “IC reporter” mice. Source data are provided as a Source Data File.