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Kidney Week

Abstract: FR-PO614

The Effect of Slc7a9 Knockout in Dahl SS Rats on Blood Pressure, Metabolism, and Kidney Function

Session Information

Category: Genetic Diseases of the Kidneys

  • 1202 Genetic Diseases of the Kidneys: Non-Cystic

Authors

  • Kravtsova, Olha, University of South Florida Department of Molecular Pharmacology and Physiology, Tampa, Florida, United States
  • Tan, Yifan, Aarhus University Department of Biomedicine, Aarhus, Denmark
  • Levchenko, Vladislav, University of South Florida Department of Molecular Pharmacology and Physiology, Tampa, Florida, United States
  • Zietara, Adrian P., University of South Florida Department of Molecular Pharmacology and Physiology, Tampa, Florida, United States
  • Dissanayake, Lashodya Vindana, University of South Florida Department of Molecular Pharmacology and Physiology, Tampa, Florida, United States
  • Palygin, Oleg, Medical University of South Carolina Department of Medicine, Charleston, South Carolina, United States
  • Rinschen, Markus M., Aarhus University Department of Biomedicine, Aarhus, Denmark
  • Staruschenko, Alexander, University of South Florida Department of Molecular Pharmacology and Physiology, Tampa, Florida, United States
Background

Amino acid balance plays a crucial role in regulating blood pressure and kidney function, impacting overall cardiovascular health. Mutations in the Slc7a9 gene, which encodes b(0,+)-type amino acid transporter 1 (b(0,+)AT1) responsible for transporting dibasic amino acids (AA) and cystine, are associated with chronic kidney disease (CKD) and reduced glomerular filtration rate. Patients with cystinuria have a higher risk of developing hypertension due to renal impairment. However, the precise role of AA balance in the development of hypertension and CKD remains incompletely understood. We hypothesized that knockout of Slc7a9 on the Dahl salt-sensitive background (SSSlc7a9-/-) will enhance the excretion of dibasic AAs and disrupt AA homeostasis, thereby affecting blood pressure and kidney function.

Methods

The Slc7a9-/- rat model was generated on the Dahl SS background by CRISPR/Cas9. The mutation was confirmed by RT-qPCR and Western blotting. Transcriptomic, proteomic, and targeted metabolomic analyses were performed.

Results

Both male and female knockout rats exhibited reduced body weight, hepatic steatosis, lower diuresis, and both hexagonal and needle crystals in urine sediments. Loss of function of b(0,+)AT1 increased the fractional excretion of several AAs, most notably arginine (0.25 ± 0.1 & 76 ± 18 %, p<0.003), lysine (0.13 ± 0.03 & 39 ± 9 %, p<0.003), 3-methylhistidine (1.3 ± 0.5 & 36 ± 9 %, p<0.003) and ornithine (0.1 ± 0.04 & 21 ± 5 %, p<0.002). Regarding urine metabolites related to the tricarboxylic acid cycle, we observed a decrease in acetoacetic acid and an increase in glutaric and citric acid in Slc7a9-/- rats. Following the high salt (4% NaCl) diet for 3 weeks, female Slc7a9-/- rats but not male Slc7a9-/- rats displayed higher mean arterial pressure compared to Slc7a9+/+ (184 ± 10 & 144 ± 6 mmHg). The following proteomic and transcriptomic analyses uncovered several pathways that exhibited differential regulation between Slc7a9+/+ and Slc7a9-/-. For instance, it was found that “α-amino acid-“, “cellular-“ and “glutamine family AA” metabolic processes were targeted.

Conclusion

Based on our data, it can be inferred that the knockout of Slc7a9 disrupts AA metabolism, which likely contributes to the effects on blood pressure and metabolic processes.

Funding

  • Other NIH Support