Generation of -Cre mice for investigation of intercalated cells and the collecting duct.

Kidney intercalated cells (ICs) maintain acid-base homeostasis and recent studies have demonstrated that they function in the kidney's innate defense. To study kidney innate immune function, ICs have been enriched using vacuolar ATPase (V-ATPase) B1 subunit ()-Cre (B1-Cre) mice. Although is considered kidney specific, it is expressed in multiple organ systems, both in mice and humans, raising the possibility of off-target effects when using the Cre-lox system. We have recently shown using single-cell RNA sequencing that the gene that codes for the V-ATPase G3 subunit (mouse gene: ; human gene: ; protein abbreviation: G3) mRNA is selectively enriched in human kidney ICs. In this study, we generated -Cre (G3-Cre) reporter mice using CRISPR/CAS technology and crossed them with mice. The resultant G3-CreTdt progeny was evaluated for kidney specificity in multiple tissues and found to be highly specific to kidney cells with minimal or no expression in other organs evaluated compared with B1-Cre mice. Tdt cells were flow sorted and were enriched for IC marker genes on RT-PCR analysis. Next, we crossed these mice to ihCD59 mice to generate an IC depletion mouse model (G3-CreihCD59). ICs were depleted in these mice using intermedilysin, which resulted in lower blood pH, suggestive of a distal renal tubular acidosis phenotype. The G3-Cre mice were healthy, bred normally, and produce regular-sized litter. Thus, this new "IC reporter" mice can be a useful tool to study ICs. This study details the development, validation, and experimental use of a new mouse model to study the collecting duct and intercalated cells. Kidney intercalated cells are a cell type increasingly recognized to be important in several human diseases including kidney infections, acid-base disorders, and acute kidney injury.