Dipeptidyl peptidase 3 modulates the renin-angiotensin system in mice

Dipeptidyl peptidase 3 (DPP3) is a zinc-dependent hydrolase involved in degrading oligopeptides with 4-12 amino acid residues. It has been associated with several pathophysiological processes, including blood pressure regulation, pain signaling, and cancer cell defense against oxidative stress. However, the physiological substrates and the cellular pathways that are potentially targeted by DPP3 to mediate these effects remain unknown. Here, we show that global DPP3 deficiency in mice (DPP3^-/-) affects the renin-angiotensin system (RAS). LC-MS-based profiling of circulating angiotensin peptides revealed elevated levels of angiotensin II, III, IV, and 1-5 in DPP3^-/- mice, whereas blood pressure, renin activity, and aldosterone levels remained unchanged. Activity assays using the purified enzyme confirmed that angiotensin peptides are substrates for DPP3. Aberrant angiotensin signaling was associated with substantially higher water intake and increased renal reactive oxygen species formation in the kidneys of DPP3^-/- mice. The metabolic changes and altered angiotensin levels observed in male DPP3^-/- mice were either absent or attenuated in female DPP3^-/- mice, indicating sex-specific differences. Taken together, our observations suggest that DPP3 regulates the RAS pathway and water homeostasis by degrading circulating angiotensin peptides.