Construction and Evaluation of a Novel Organic Anion Transporter 1/3 CRISPR/Cas9 Double-Knockout Rat Model

Abstract

Background: Organic anion transporter 1 (OAT1) and OAT3 have an overlapping spectrum of substrates such that one can exert a compensatory effect when the other is dysfunctional. As a result, the knockout of either OAT1 or OAT3 is not reflected in a change in the excretion of organic anionic substrates. To date, only the mOAT1 and mOAT3 individual knockout mouse models have been available. Methods: In this study, we successfully generated a Slc22a6/Slc22a8 double-knockout (KO) rat model using CRISPR/Cas9 technology and evaluated its biological properties. Results: The double-knockout rat model did not expression mRNA for rOAT1 or rOAT3 in the kidneys. Consistently, the renal excretion of p-aminohippuric acid (PAH), the classical substrate of OAT1/OAT3, was substantially decreased in the Slc22a6/Slc22a8 double-knockout rats. The relative mRNA level of Slco4c1 was up-regulated in KO rats. No renal pathological phenotype was evident. The renal elimination of the organic anionic drug furosemide was nearly abolished in the Slc22a6/Slc22a8 knockout rats, but elimination of the organic cationic drug metformin was hardly affected. Conclusions: These results demonstrate that this rat model is a useful tool for investigating the functions of OAT1/OAT3 in metabolic diseases, drug metabolism and pharmacokinetics, and OATs-mediated drug interactions.

Remote effects of kidney drug transporter OAT1 on gut microbiome composition and urate homeostasis

“…In rats with a CRISPR/Cas9-mediated double KO of OAT1 (Slc22a6) and OAT3 (Slc22a8), renal dysfunction was observed in 4-week-old rats, but this was ameliorated by 7 weeks ( 57 ). This was apparently due to a compensatory increase in renal SLCO4C1 expression by 7 weeks ( 57 ).…”

“…In rats with a CRISPR/Cas9-mediated double KO of OAT1 (Slc22a6) and OAT3 (Slc22a8), renal dysfunction was observed in 4-week-old rats, but this was ameliorated by 7 weeks ( 57 ). This was apparently due to a compensatory increase in renal SLCO4C1 expression by 7 weeks ( 57 ). Previous work has shown that overexpression of the OATP transporter, SLCO4C1, has a protective effect on 5/6 nephrectomy rats modeling CKD by reducing systemic uremic toxin levels ( 58 ).…”