In hypertension, end organ damage (EOD) is due in part to the mechanical forces exerted by high blood pressure (BP); however, other mechanisms such as inflammation, oxidative stress, the RAS, and genetic predisposition, all play key roles in its pathogenesis. In hypertension, Acetyl-Ser-Asp-Lys-Pro (Ac-SDKP), a naturally occurring peptide hydrolyzed mainly by ACE, reduces cardiovascular and renal inflammation and fibrosis without lowering BP. We have evidence that Ac-SDKP mediates some of the anti-fibrotic and anti-inflammatory effects of ACE inh and also prevents experimental autoimmune myocarditis in rats. Thus we propose to test the general hypothesis that in hypertension Ac-SOKP shifts the balance between proinflammatory/ pro-oxidative and anti-inflammatory/anti-oxidative systems in favor of the latter by decreasing innate and adaptive immunity and thus slowing the development of EOD. Furthermore, the effects of Ac-SOKP on BP and EOD are related to the degree of participation of innate and adaptive immunity in the pathogenesis of hypertension and EOD. This hypothesis will be studied in 3 aims.
Aim I : In hypertensive Dahl salt-sensitive rats (Dahl SS) and in mice with systemic lupus erythematosus and hypertension, a model of autoimmune disease, Ac-SDKP acts as an immune modulator, reducing innate and adaptive immunity and thus EOD. Some of the effects of Ac-SDKP depend on the degree of participation of innate and adaptive immunity in the pathogenesis of hypertension and EOD.
Aim II : The effects of ACE inh on the proinflammatory transcription factor NF-kB, T{H} cells and Treg cells are mediated by an increase in Ac-SDKP.
Aim III : The effects of Ac-SDKP are multiphasic; central to these effects are decreases in: 1) the proinflammatory transcription factor NF-KB, 2) differentiation and maturation of dendritic cells (DCs), 3) DC transformation of T cells into effector T cells, and 4) T{H} cell proliferation, activation, migration, and differentiation into pro-inflammatory phenotypes. The effects of Ac-SDKP on T H are partly due to an increase in T{reg} cells. Project I is related to 1) III and IV which also study Dahl SS; 2) II and III, which also study the pathogenesis of EOD; and 3) II and IV which also study Ang II. Project I will use all 4 Cores.
Hypertension is a major risk factor for cardiovascular renal morbidity and mortality. If treatment with Ac-SDKP can decrease an over-activation of the immune system and thereby reduce hypertensive EOD in Dahl SS rats, as well as SLE-hyp, it could improve treatment of not only hypertensive EOD but also of other conditions that lead to cardiovascular and renal disease, such as diabetes, autoimmune diseases such as SLE, or even transplant rejection.
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