Abstract 4: Genetic Deletion of CD247 in Dahl Salt-Sensitive (SS) Rats Attenuates Hypertension and Renal Damage
The CD3 zeta chain (CD247), a gene involved in T cell signaling, has been demonstrated to associate with hypertension in human genetic studies. Hypertension and renal damage in the Dahl SS rat are associated with an increase in infiltrating T cells in the kidney. There are numerous descriptions of the role of CD247 as a modulator of T cell receptor signaling, but little is known about the role of this gene product in hypertension. To test the functional role of CD247 in hypertension and renal disease, zinc finger nucleases targeting exon 1 were injected into Dahl SS/JrHsdMcwi embryos. The resulting mutation is a 13-bp frameshift deletion of bases 155-167 in exon 1 of CD247 leading to a predicted stop codon within 19 bases of the mutation. Western blotting confirmed the absence of CD247 protein in the thymus, demonstrating a null mutation, and flow cytometry of circulating T and B-cells in wild type (WT) and CD247 null mutant rats (n=5-10/group) demonstrated that the mutants have a significant decrease in CD3+ T-cells (0.04±0.01 vs 4.6±0.5 x 107 cells/ml) and increased CD45R+ B-cells (4.1±0.4 vs 1.2±0.2 x 107 cells/ml). Studies were then performed on age-matched, male, WT and CD247 null mutant rats fed a 4.0% NaCl diet for three weeks. The infiltration of CD3+ T-cells into the kidney following high salt was significantly blunted in the CD247 mutant rats (1.4±0.4 x 105 cells/kidney) compared to the WT (8.7±2.0 x 105 cells/kidney). Accompanying the reduced infiltration of T-cells, mean arterial blood pressure was significantly lower in the CD247 null mutant rats than the WT (134±1 vs 151±2 mmHg). As an index of kidney disease, urinary albumin and protein excretion rate were significantly reduced in CD247 null mutants (17±1 and 62±2 mg/day, respectively) compared to WT (49±3 and 121±5 mg/day, respectively). Finally, a histological analysis revealed that the glomerular and tubular damage in the kidneys of the WT rats fed high salt was also attenuated in the CD247 null mutants. This new experimental model provides evidence that T cells are required for the full development of Dahl SS hypertension and indicate that the association between CD247 and hypertension in humans may be related to altered immune cell function. Supported by HL-29587, DK-62803, and RC2-HL101681.
- © 2012 by American Heart Association, Inc.