ATP-Gated P2X7-Ion Channel on Kidney-Resident Natural Killer T Cells and Memory T Cells in Intrarenal Inflammation

Background: The P2X7 ion channel, a key sensor of sterile inflammation, has been implicated as a therapeutic target in glomerulonephritis, and P2X7-antagonistic nanobodies can attenuate experimental glomerulonephritis. However, little is known about the expression of P2X7 on renal immune cells. Methods: We used conventional immunofluorescence of kidney sections as well as intraperitoneal injection of nanobodies in mice followed by flow cytometry analysis of parenchymal T cells and RNA-sequencing to elucidate the expression and function of P2X7 on parenchymal and vascular immune cells in the mouse kidney. Results: Our study showed that parenchymal T cells, including a large subset of natural killer T cells and CD69 + tissue-resident memory T cells, display much higher cell surface levels of P2X7 than vascular T cells. After a single intraperitoneal injection of P2X7-blocking nanobodies, P2X7 on parenchymal T cells was fully occupied by the injected nanobodies within 30 min. This resulted in an effective protection of these cells from NAD-induced cell death during cell preparation. Conversely, systemic injection of NAD that mimics sterile inflammation results in the selective depletion of P2X7 hi CD69 hi T cells from the kidney parenchyma. Conclusions: Our study uncovered a novel purinergic regulatory mechanism affecting kidney-resident T cell populations.