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Novel CRISPR/Cas9 Munich Wistar Frömter rat model carrying disease‐causing mutant Actn4 demonstrates salt‐sensitive hypertension
Author(s) -
Feng Di,
Kurth Terry,
Stumpf Megan,
Grzybowski Michael,
Geurts Aron,
Sandoval Ruben,
Rhodes George,
Molitoris Bruce,
Pollak Martin,
Cowley Allen
Publication year - 2021
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.2021.35.s1.01666
Subject(s) - mutant , mean arterial pressure , podocyte , medicine , endocrinology , biology , phenotype , blood pressure , mutation , kidney , microbiology and biotechnology , genetics , gene , proteinuria , heart rate
Defects in the podocyte cytoskeleton contribute to podocyte vulnerability and proteinuric kidney disease. Genetic mutations in Alpha‐actinin 4 (ACTN4)—an essential crosslinker of the actin cytoskeleton—cause an autosomal dominant form of chronic kidney disease in humans. Although the role of the genetic mutation in podocyte and glomerular injury has been characterized, the effect of the genetic mutation on blood pressure regulation has not been investigated. To address this gap, we used CRISPR/Cas9 to generate the first Munich Wistar Frömter (MWF)rat model carrying the human disease‐causing K255E ACTN4 mutation. After identification of the founder, we intercrossed heterozygous rats from the F1 generation to yield male and female WT, heterozygous, and homozygous littermates for phenotypic study. Mean arterial pressure (MAP) was measured daily via telemetry, implanted at 5‐6 weeks of age. After 3 days of baseline MAP measurement on 1% salt diet, MAP was measured for 14 days on 4% salt. In males, homozygous mutant rats demonstrated the greatest increase in MAP over time, followed by heterozygous and then WT (Figure 1). At day 14, homozygous mutant rats had significantly higher MAP (mean MAP = 174 mmHg, standard error of the mean [SEM] = 12 mmHg) compared to WT (mean MAP = 123 mmHg, SEM = 2 mmHg; p‐value < 0.05). Heterozygous mutant rats also had significantly higher MAP (mean MAP = 136 mmHg, SEM = 4 mmHg; p‐value < 0.05) compared to WT, although to a lesser degree than homozygous mutant rats. In females, homozygous mutant rats demonstrated an increase in MAP over time; heterozygous and WT also increased but to a lesser degree (Figure 2). At day 14, homozygous mutant rats had significantly higher MAP (mean MAP = 155 mmHg, SEM = 3 mmHg) compared to WT (mean MAP = 119 mmHg, SEM = 1 mmHg; p‐value < 0.05), but heterozygous mutant rats were not different (mean MAP = 123 mmHg, SEM = 3 mmHg; p‐value = 0.36). Our preliminary findings suggest that disease‐causing mutant ACTN4 is associated with salt‐sensitive hypertension. Our heterozygous MWF rat model—more faithfully mimicking the human phenotype—can be further studied to reveal the mechanisms by which mutant ACTN4 leads to renal disease and salt‐sensitive hypertension.