Abstract 011: Cluster Of Differentiation 14 (CD14) Inhibits NADPH Oxidase 2 (NOX2)-Derived Oxidative Stress In Hematopoietic Cells And Modulates Dahl Salt-Sensitive Hypertension And Renal Damage

Abstract

We recently discovered that genetic deletion of CD14 in Dahl SS rats (CD14-/-) amplifies the development of salt-sensitive hypertension and renal damage in females. Interestingly, the expression of CD14 in leukocytes and the level of plasma CD14 protein are increased in cardiovascular disease and hypertension in humans. An examination of macrophages from CD14-/- females revealed enhanced production of superoxide from NOX2 compared to Dahl SS. Furthermore, a double knockout Dahl SS strain lacking both CD14 and functional NOX2 (DKO) exhibits significantly reduced salt-induced hypertension and associated renal damage, indicating that free radical production from NOX2 is likely mediating the amplification of disease following CD14 deletion. The present study examined the specific effects of CD14 and NOX2 deletion in hematopoietic cells via a total body irradiation/bone marrow transfer (TBI/BMT) approach. Female Dahl SS recipients were irradiated (11Gy) then received either CD14 or DKO bone marrow transplantation via tail vein injection. Rats that received DKO hematopoietic cells had blunted mean arterial pressure (147±4 mmHg, n=3, p=0.052) versus those that received CD14-/- (179±19mmHg, n=3) in response to a 3-week high salt challenge (HS, 4.0% NaCl, AIN-76A). As an index of renal damage, albuminuria was significantly reduced in the DKO (110.3±7 mg/day, n=3, p<0.01) compared to the CD14-/- (280.9±42 mg/day, n=3) at HS day 21. Flow cytometric analysis of isolated renal immune cells indicated a reduction in renal inflammation in the DKO compared to the CD14-/-. There were fewer CD45+ total leukocytes (2.8x10 6 vs 3.8x10 6 cells/kidney, p<0.05) and CD11b/c+ monocytes/macrophages (2.4x10 6 vs 3.3x10 6 cells/kidney, n=3, p<0.05) in DKO versus CD14-/- kidneys. Finally, to document the TBI/BMT, macrophages from CD14-/- rats produced 7-fold greater superoxide from NOX2 when stimulated with 12-phorbol myristate 13-acetate compared to DKO macrophages. Together, these data suggest a regulatory role of CD14 in hematopoietic cells to reduce oxidative stress from NOX2 in the kidney of female Dahl SS rats during salt-sensitive hypertension and associated renal disease.