Cellular Senescence as an Underlying Mechanism of Kidney Injury in a Mouse Model of Preeclampsia

Background: Preeclampsia (PE) is a hypertensive complication of pregnancy often associated with kidney injury which is characterized by proteinuria and podocyturia. The mechanism leading to kidney injury in PE, however, is poorly understood. Our recently published data indicate the presence of cellular senescence in women with PE. We hypothesized that cellular senescence is present in the kidneys of mice (IL-10KO mouse model of PE), and that senescence-associated genes are upregulated in podocytes and endothelial cells of kidneys in these animals. Methods: We utilized the mouse model where PE is induced by i.p. injection of human PE sera into 10–12-week-old animals. PE is observed around the 18th gestational day when the animals are euthanized. Regular pregnant mice with no PE serum injected (PG) served as a control group. We measured blood pressure, proteinuria, urinary alpha Klotho (α-Klotho), and the expressions of senescence-associated genes in the kidneys (n=4-5 per group). To identify which senescence-associated genes are affected in podocytes and endothelial cells, which are injured in preeclampsia, we performed kidney single-cell RNA sequencing (scRNAseq) in the PG (n=2) and PE groups (n=3). Results: Significant increase in blood pressure and proteinuria was observed in PE mice. Urinary α-Klotho, an anti-aging marker, was significantly decreased in PE mice compared to the PG group. Significant decrease in α-Klotho was observed in PE mice upon injection of PE serum compared to the values before injection. Kidneys of PE mice had increased expressions of senescence-associated genes p16, il6, and pai1. Using scRNAseq we clustered 15 transcriptionally different kidney cell types based on cell type-specific marker genes. Among those cells we identified five subclusters of endothelial cells and four of podocytes. We compared and identified 7 differentially expressed genes associated with senescence in endothelial cells (Ccl5, Csf2rb, Cxcl1, Cxcl10, Cxcl2, Igfbp5, and Il15) and 10 in podocytes (Angpt1, Areg, C3, Ccl7, Cxcl2, Gem, Il15, Nrg1, Pappa, Tnf). Conclusion: These results indicate that cellular senescence could represent a potential mechanism of kidney injury in preeclampsia.