Elevated Salt or Angiotensin II Levels Induce CD38+ Innate Immune Cells in the Presence of Granulocyte-Macrophage Colony Stimulating Factor

Abstract

Hypertension (HTN) impacts almost half of adults, predisposing them to cardiovascular disease and renal damage. Salt-sensitive HTN (SSHTN) and angiotensin II (A2)-induced HTN (A2HTN) both involve immune system activation and renal innate immune cell infiltration. Subpopulations of activated [Cluster of differentiation 38 (CD38)] innate immune cells, such as macrophages and dendritic cells (DCs), play distinct roles in modulating renal function and blood pressure. It is unknown how these cells become CD38+ or which subtypes are pro-hypertensive. When bone marrow-derived monocytes (BMDMs) were grown in granulocyte-macrophage colony stimulating factor (GM-CSF) and treated with salt or A2, CD38+ macrophages and CD38+ DCs increased. The adoptive transfer of GM-CSF-primed BMDMs into mice with either SSHTN or A2HTN increased renal CD38+ macrophages and CD38+ DCs. Flow cytometry revealed increased renal M1 macrophages and type-2 conventional DCs (cDC2s), along with their CD38+ counterparts, in mice with either SSHTN or A2HTN. These results were replicable in vitro. Either salt or A2 treatment of GM-CSF-primed BMDMs significantly increased bone marrow-derived (BMD)-M1 macrophages, CD38+ BMD-M1 macrophages, BMD-cDC2s, and CD38+ BMD-cDC2s. Overall, these data suggest that GM-CSF is necessary for the salt or A2 induction of CD38+ innate immune cells, and that CD38 distinguishes pro-hypertensive immune cells. Further investigation of CD38+ M1 macrophages and CD38+ cDC2s could provide new therapeutic targets for both SSHTN and A2HTN.