TET2 germline variants promote kidney disease by impairing DNA repair and activating cytosolic nucleotide sensors

Abstract

Genome-wide association studies (GWAS) have identified over 800 loci associated with kidney function, yet the specific genes, variants, and pathways involved remain elusive. By integrating kidney function GWAS with human kidney expression and methylation quantitative trait analyses, we identified Ten-Eleven Translocation (TET) DNA demethylase 2 (TET2) as a novel kidney disease risk gene. Utilizing single-cell chromatin accessibility and CRISPR-based genome editing, we highlight GWAS variants that influence TET2 expression in kidney proximal tubule cells. Experiments using kidney/tubule-specific Tet2 knockout mice indicated its protective role in cisplatin-induced acute kidney injury, as well as in chronic kidney disease and fibrosis induced by unilateral ureteral obstruction or adenine diet. Single-cell gene profiling of kidneys from Tet2 knockout mice and TET2-knockdown tubule cells revealed the altered expression of DNA damage repair and chromosome segregation genes, notably including INO80, another kidney function GWAS target gene itself. Remarkably, both TET2-null and INO80-null cells exhibited an increased accumulation of micronuclei after injury, leading to the activation of cytosolic nucleotide sensor cGAS-STING. Genetic deletion of cGAS or STING in kidney tubules, or pharmacological inhibition of STING, protected TET2-null mice from disease development. In conclusion, our findings highlight TET2 and INO80 as key genes in the pathogenesis of kidney diseases, indicating the importance of DNA damage repair mechanisms.

Here, the authors have integrated genome-wide association data with functional genomics data relevant to the kidney and performed in vitro and in vivo experiments which support TET2 as a kidney disease risk gene.