|Title||Comparison of folate-conjugated rapamycin versus unconjugated rapamycin in an orthologous mouse model of polycystic kidney disease.|
|Publication Type||Journal Article|
|Year of Publication||2018|
|Authors||Kipp, KR, Kruger, SL, Schimmel, MF, Parker, N, Shillingford, JM, Leamon, CP, Weimbs, T|
|Journal||Am J Physiol Renal Physiol|
|Date Published||2018 May 02|
Autosomal-dominant polycystic kidney disease (ADPKD) is a very common genetic disease leading to renal failure. Numerous aberrantly regulated signaling pathways have been identified as promising molecular drug targets for ADPKD therapy. In rodent models, many small-molecule drugs against such targets have proven effective in reducing renal cyst growth. For example, mTOR inhibition with rapamycin greatly ameliorates renal cystic disease in several rodent models. However, clinical trials with mTOR inhibitors were disappointing largely due to the intolerable extra-renal side effects during long-term treatment with these drugs. Most other potential drug targets in ADPKD are also widely expressed in extra-renal tissues which makes it likely that untargeted therapies with small-molecule inhibitors against such targets will lead to systemic adverse effects during the necessary long-term treatment of years and decades in ADPKD patients. To overcome this problem, we previously demonstrated that folate-conjugated rapamycin (FC-rapa) targets polycystic kidneys due to the high expression of the folate receptor (FRα), and that treatment of a non-ortholgous PKD mouse model leads to inhibition of renal cyst growth. Here we show, in a head-to-head comparison with unconjugated rapamycin, that FC-rapa inhibits renal cyst growth, mTOR activation, cell cycling and fibrosis in an orthologous Pkd1 mouse model. Both unconjugated rapamycin and FC-rapa are similarly effective on polycystic kidneys in this model. However, FC-rapa lacks the extra-renal effects of unconjugated rapamycin, in particular immunosuppressive effects. We conclude that folate-conjugation is a promising avenue for increasing the tissue specificity of small-molecule compounds to facilitate very long-term treatment in ADPKD.
|Alternate Journal||Am. J. Physiol. Renal Physiol.|