The Ngal reporter mouse detects the response of the kidney to injury in real time

Abstract

Many proteins have been proposed to act as surrogate markers of organ damage, yet for many candidates the essential characteristics which link the protein to the injured organ have not yet been described. We generated an NGAL-reporter mouse by inserting a di-fusion reporter gene, Luciferase2(Luc2)/mCherry(mC) into the Ngal locus. The Ngal-Luc2/mC reporter accurately recapitulated the endogenous message and illuminated injuries in vivo in real-time. In the kidney, Ngal-Luc2/mC imaging showed a sensitive, rapid, dose-dependent, reversible, and organ and cellular specific relationship with tubular stress, which quantitatively paralleled urinary Ngal (uNgal). Unexpectedly, specific cells of the distal nephron were the source of uNgal. Cells isolated from Ngal-Luc2/mC mice could also track both the onset and the resolution of the injury, and monitor the actions of NF-κB inhibitors and antibiotics in the case of infection. Accordingly, the imaging of Ngal-Luc2/mC mice and cells identified injurious and reparative agents which effect kidney damage.

Origin of regenerating tubular cells after acute kidney injury

“…These findings also suggest that tubular cells respond to injury in a graded fashion. Transcriptional activity of PEC-rtTA mice mimics the expression of KIM-1, an injury marker of the proximal tubule, and thus differs from the neutrophil gelatinase-associated lipocalin (NGAL) reporter mouse (18), where transcriptional activity is more specific for the distal tubule and collecting duct system.…”

A Tissue-Specific Role for Nlrp3 in Tubular Epithelial Repair after Renal Ischemia/Reperfusion

“…Herein, we observed that only renal Nlrp3 mediates renal dysfunction on the basis of plasma creatinine levels (Supplemental Figure S1, A and B). We next investigated the renal damage markers KIM-1 22 and NGAL 23 to investigate proximal versus distal damage. Both chimeras showed an expression pattern similar to plasma urea and creatinine with respect to KIM-1 ( Figure 2C) and NGAL ( Figure 2D), confirming that both leukocyte-and renalassociated Nlrp3s are detrimental after renal IR injury and indicating that distinct Nlrp3 expression has no differential effect on proximal versus distal tubular damage.…”

Cell-specific translational profiling in acute kidney injury

“…Analysis of temporal and spatial differences in their expression highlights the cellular complexity of the AKI response (ref. 18 and see Supplemental Figure 3; supplemental material available online with this article; doi:10.1172/JCI72126DS1), although the cellular diversity of the pathophysiological response and repair process has not been systematically addressed.…”