Targeted disruption of Adamts16 gene in a rat genetic model of hypertension

Abstract

A disintegrin-like metalloproteinase with thrombospondin motifs-16 (Adamts16) is an important candidate gene for hypertension. The goal of the present study was to further assess the candidacy of Adamts16 by targeted disruption of this gene in a rat genetic model of hypertension. A rat model was generated by manipulating the genome of the Dahl Salt-sensitive (S) rat using zinc-finger nucleases, wherein the mutant rat had a 17 bp deletion in the first exon of Adamts16, introducing a stop codon in the transcript. Systolic blood pressure (BP) of the homozygous Adamts16 mutant rats was lower by 36 mmHg compared with the BP of the S rats. The Adamts16 mutant rats exhibited significantly lower aortic pulse wave velocity and vascular media thickness compared with S rats. Scanning electron and fluorescence microscopic studies indicated that the mechanosensory cilia of vascular endothelial cells from the Adamts16 mutant rats were longer than that of the S rats. Furthermore, Adamts16 mutant rats showed splitting and thickening of glomerular capillaries and had a longer survival rate, compared with the S rats. Taken together, these physiological observations functionally link Adamts16 to BP regulation and suggest the vasculature as the potential site of action of Adamts16 to lower BP.espite strong evidence that susceptibility or resistance to the development of hypertension is heritable, the identification of genetic variants that cause blood pressure (BP) to rise into a hypertensive state has remained difficult (1, 2). Classic genetic mapping and association studies in both humans and in rats point to several genetic elements as potential candidates causing hypertension (3, 4). Most of the prioritized candidate genes for hypertension await functional assessments.Linkage analysis in the Quebec Family Study identified a quantitative trait locus (QTL) for systolic BP on human chromosome 5p15 (5). The corresponding comparative segment of human chromosome 5p15 on rat chromosome 1 is also linked to a BP QTL in rats (6). Improved resolutions of this locus in rats were obtained through iterative substitution mapping using strains differentially susceptible to the development of hypertension (6-10). A disintegrin-like metalloproteinase with thrombospondin motifs-16 (Adamts16), which was the only known gene with exonic variants within the highly resolved congenic interval, was prioritized as a candidate BP quantitative trait gene (QTG) (8). More importantly, following the congenic mapping study in rats, human allelic variants of Adamts16 were confirmed as being associated with BP in two independent cohorts, one of which was the Quebec Family Study (8). Taken together, all these studies point to Adamts16 as a prominent candidate locus linked to BP control across two species. However, due to the limitations of recombination frequencies, both the linkage and substitution mapping studies in rats cannot validate Adamts16 as the BP QTG because of the presence of other candidate variants within the linked or introgressed flanking genomic ...

Salt Sensitivity of Blood Pressure

“…However, even with high-resolution substitution mapping, there are usually additional variants flanking a substituted candidate gene, requiring genetic engineering to sort out the significance of the finding. 111 Furthermore, chromosomal regions without coding variants or with variants in intronic segments that may have possible regulatory functions have also been associated with hypertension, but the mechanism of the association remains obscure. [112][113][114] Results of this approach make it clear that the SS phenotype of rats is determined by multiple different genes or by the combination of their effects into a polygenic form of inheritance.…”

Base-Resolution Maps of 5-Methylcytosine and 5-Hydroxymethylcytosine in Dahl S Rats

“…The genetic basis of salt-sensitive hypertension in humans and in the SS rat has been a subject of intensive investigation. 2,3,4 …”

Transcriptional Regulation by the Wilms Tumor Protein, Wt1, Suggests a Role of the Metalloproteinase Adamts16 in Murine Genitourinary Development

“…Interestingly, recent disruption of the Adamts16 gene in Dahl Salt-sensitive rats caused splitting and thickening of glomerular capillaries in addition to a significant reduction of arterial blood pressure (50). Renal damage was associated with increased proteinuria, suggesting that Adamts16 is indeed necessary for the structural and functional preservation of the kidneys in this model of genetic hypertension (50).…”