Parental Dietary Protein Source and the Role of CMKLR1 in Determining the Severity of Dahl Salt-Sensitive Hypertension

Abstract

Studies from our laboratory have revealed an important role for the maternal diet and the dietary protein source in the development of hypertension and renal injury in Dahl salt-sensitive (SS) rats. The current study sought to compare salt-induced hypertension, renal damage, and immune cell infiltration in the offspring of breeders fed either a casein- or gluten-based diet, with the hypothesis that offspring from gluten-fed breeders would fail to develop these SS phenotypes. When fed identical diets post-weaning, the F1 generation gluten offspring demonstrated lower mean arterial pressure (149.1±3.1 versus 162.5±5.8 mm Hg), albuminuria (166.2±34.6 versus 250.9±27.8 mg/day), and outer medullary protein casting (7.4±0.8% versus 13.1±1.3%) in response to high salt compared with the casein offspring (n=9-11). The gluten offspring also had fewer CD45+ leukocytes, CD11b/c+ monocytes/macrophages, CD3+ T cells, and CD45R+ B cells infiltrating the kidney. Analysis of the F2 generation gluten offspring also exhibited lower mean arterial pressure and renal damage compared with rats born from casein breeders (n=7-9), with no difference in renal immune cell infiltration. CMKLR1-receptor for the novel prohypertensive adipokine chemerin-was found via polymerase chain reaction array to be significantly upregulated (2.99-fold) in renal T cells isolated from F2 offspring of casein-fed versus gluten-fed parents. Furthermore, CMKLR1 inhibition via α-NETA (2-[α-naphthoyl] ethyltrimethylammonium iodide) treatment significantly attenuated renal immune cell infiltration, hypertension, and renal damage in SS rats fed high salt. Together, these data demonstrate the influence of the parental diet in determining the salt-induced hypertension, renal damage, and inflammatory phenotype of the offspring.

Keywords: T lymphocytes; animals; dietary proteins; kidney; rats.

Figure 1.

The F1 SS/gluten offspring were born from Dahl SS breeders switched to the modified wheat gluten chow just prior to conception. (A) Mean arterial blood pressure, (B) urinary albumin excretion, (C) medullary protein cast formation, and (D) glomerular damage were all lower after 3 weeks of 4.0% high salt challenge in the F1 SS/gluten offspring compared to SS/casein offspring. n=9–14, *p<0.05 and **p<0.01 versus SS/casein via Two Way RM ANOVA (A-B) or t-test (C-D).

Figure 2.

Examination of the renal infiltrating immune cell profile of CD45+ leukocytes (A), CD11b/c+ monocyte/macrophages (B), and CD3+ T-cells, CD3+CD4+ helper T-cells, CD3+CD8+ cytotoxic T-cells, and CD45R+ B-cells (C) showed a reduction in F1 SS/gluten offspring after 3 weeks of 4.0% high salt challenge compared to SS/casein offspring. n=14, *p<0.05 and **p<0.01 versus SS/casein via One Way ANOVA.

Figure 3.

F2 SS/gluten offspring had parents who were born, maintained, and bred on the modified wheat gluten diet. Compared to the SS/casein offspring, the F2 offspring from gluten breeders demonstrated lower mean arterial pressure (A) and significantly improved renal injury indicated by reduced albuminuria (B), medullary protein cast formation (C), and glomerular damage (D) after 3 weeks of 4.0% high salt. n=7–10, *p<0.05 and **p<0.01 versus SS/casein via Two Way RM ANOVA (A-B) or t-test (C-D).

Figure 4.

Investigation of the renal infiltrating immune cell profile of CD45+ leukocytes (A), CD11b/c+ monocyte/macrophages (B), and CD3+ T-cells, CD3+CD4+ helper T-cells, CD3+CD8+ cytotoxic T-cells, and CD45R+ B-cells (C) showed no difference between the F2 SS/gluten and SS/casein offspring after 3 weeks of 4.0% high salt challenge. n=7–10.

Figure 5.

Daily administration of small molecule CMKLR1 inhibitor, α-NETA (20 mg/kg s.c.), prevented Dahl SS rats from developing salt-induced hypertension (A) and renal damage, demonstrated by improved albuminuria (B), medullary protein cast formation (C), and glomerular morphology (D). This was accompanied with fewer immune cells infiltrating the kidneys of α-NETA-treated SS rats after 3 weeks of high salt (E). CD45: leukocytes, CD11b/c+: monocyte/macrophages, CD3+: T-cells, CD4+: helper T-cells, CD8+: cytotoxic T-cells, CD45R+: B-cells. *p<0.05 and **p<0.01 versus Vehicle via Two Way RM ANOVA (A-B), t-test (C-D), or One Way ANOVA (E).