Macrophage Accumulation and Cyst Expansion in Pkd2, Ift88, and Double Mutant Mouse Models

Kidney cyst formation occurs due to loss of cilia localized polycystin proteins (e.g., Pkd1 or Pkd2) or ciliary structure (e.g., Ift88 or Kif3a). However, cyst progression is more rapid in polycystin mutant mice compared to cilia mutant mice, and loss of cilia in the polycystin mutant background (e.g., Pkd2 and Kif3a mutation) greatly attenuates cyst development. This led to the proposal that the polycystins function to repress a cyst promoting pathway that is dependent on an intact cilium. Renal macrophages are also involved in regulating cyst progression, and the macrophage accumulation paralles with cyst expansion. but it is unknown whether this occurs through a cilia-dependent pathway or the consequence of cyst expansion. To address this question, we compared macrophage accumulation level and phenotypes in cystic kidneys from Pc2 mutant and Ift88; Pkd2 double mutant mice by prefromed 10x Genomics scRNAseq techniques. And to avoid the varying cyst severity in these mouse from different mutations, the cystic kidneys from Pc2 mutant and Ift88; Pkd2 double mutant mice were collected by adjusting for cystic indices rather than age. The experinment was conducted on Pkd2fl/fl ("PC2";Strain #:017292) and CAGG-CreER;Pkd2fl/fl;Ift88fl/fl ("double") mice (C57BL/6J background) mutant kidneys at 16 and 26 weeks post-tamoxifen induction, respectively. Kidneys (n=3 per mutant group, n=1 per each control group, all females; 8 total mice). The libraries were generated with the Chromium Single Cell 3' GEM, Library & Gel Bead Kit v3, following manufacturer's protocols. scRNA-seq analysis was preformed to comparing gene expression and pathway between resident and infiltraing macrophages from kidneys with simlar cyst index from PC2 and double mutant mice.