Hematopoietic loss of Y chromosome activates immune checkpoints and contributes to impaired senescent cell clearance and renal disease.

The accumulation of senescent cells contributes to morbidity and mortality; however, common mechanisms underpinning this age-associated phenomenon remain elusive. Hematopoietic loss of the Y chromosome (LOY) is the most frequently acquired somatic mutation in males, and this condition has been associated with various age-associated diseases and reduced lifespan. Therefore, we investigated the role of hematopoietic LOY in promoting cellular senescence, focusing on kidney disease because of its well-documented connection with aging and senescence. Herein, a prospective cohort study revealed that LOY in blood is associated with an increased incidence of kidney diseases. Analyses of transcriptional signatures in human kidneys found that immune cell LOY is enriched in patients with kidney disease and associated with greater amounts of cellular senescence. In male mice reconstituted with bone marrow lacking the Y chromosome, renal dysfunction was accompanied by senescent cell accumulation in models of kidney injury and advanced age. Treatment with a senolytic agent promoted senolysis and preferentially inhibited the progression of renal dysfunction in LOY mice. Hematopoietic LOY led to up-regulation of multiple immune inhibitory receptors, and treatment with the combination of antibodies targeting PD-1 (programmed cell death protein 1) and SIRPα (signal regulatory protein α) reduced senescent cell accumulation and rescued the renal pathology conferred by hematopoietic LOY in the kidney injury model. Collectively, these data indicate that hematopoietic LOY contributes to pathological conditions by impairing the clearance of senescent cells through up-regulation of immune checkpoint proteins.