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Updated: May 26, 2026
Mouse Model of Acute to Chronic Kidney Disease Transition Induced by Renal Ischemia/Reperfusion Injury
Published on: February 10, 2026
Characterization of in vivo disulfide-reduction mediated drug release in mouse kidneys
Jun J Yang1, Sumith A Kularatne, Xianming Chen
1Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, Indiana 47907, USA.
Abstract:
Due to the overexpression of a folate receptor (FR) on many malignant cells, folate-targeted drugs have been developed to improve the cancer specificity of chemotherapeutic agents. Therapeutic index is further enhanced with the use of self-immolative linkers that efficiently release the attached drug upon cellular internalization of the folate-drug conjugate. Because FR is also abundant in normal kidney proximal tubule (PT) cells, we sought to examine in real time the trafficking and release of folate-targeted drugs in the kidney in vivo. Thus, we conducted two-photon kidney imaging studies in mice utilizing a Förster resonance energy transfer (FRET) based folate conjugate that undergoes a color shift from red to green upon reduction of the disulfide bond linking folate to a surrogate drug molecule. Following infusion via intravenous injection, folate-FRET reached the kidney in its intact unreduced form. The folate-FRET conjugate was then filtered into the lumen of PT, where it was efficiently captured by FR. As FR transcytosed across PT, some disulfide reduction occurred, with reduced folate-FRET detectable in PT vesicles 30 min postinjection. Prolonged monitoring of folate-FRET in mice showed modest progression of reduction in PT cells over time. Moreover, inhibition of FR trafficking in PT cells by colchicine did not significantly affect the rate or extent of folate-FRET reduction. Finally, the lack of cytosolic accumulation of released drug surrogate in the PT suggests that drug release via disulfide bond reduction should cause little kidney toxicity.
Insights
Folate-targeted drugs are taken up by kidney cells via folate receptors (FR). Drug release in kidney proximal tubules is slow and limited, suggesting low potential for kidney toxicity from these targeted therapies.
Area of Science:
- Pharmacology
- Oncology
- Nephrology
Background:
- Folate receptors (FR) are overexpressed in many cancers, making them targets for chemotherapy.
- Folate-drug conjugates utilize FR for targeted delivery, enhanced by self-immolative linkers for drug release.
- FR are also present in normal kidney proximal tubule (PT) cells, raising concerns about potential kidney toxicity.
Purpose of the Study:
- To investigate the in vivo trafficking and drug release of folate-targeted conjugates in the kidney.
- To assess the real-time kinetics of folate-drug conjugate processing in kidney proximal tubules.
- To evaluate the potential kidney toxicity associated with FR-mediated drug release.
Main Methods:
- Two-photon kidney imaging in mice.
- Utilized a Förster resonance energy transfer (FRET)-based folate conjugate with a disulfide bond.
- Monitored conjugate uptake, trafficking, and reduction in kidney proximal tubules.
Main Results:
- Folate-FRET conjugate was efficiently captured by FR in kidney proximal tubules after intravenous injection.
- Disulfide bond reduction and drug surrogate release occurred slowly within PT vesicles.
- Colchicine inhibition of FR trafficking did not significantly alter the rate or extent of reduction.
- Limited cytosolic accumulation of the released drug surrogate was observed.
Conclusions:
- Folate-targeted drug conjugates are internalized and processed in kidney proximal tubules via FR.
- The slow rate of drug release suggests a low risk of kidney toxicity.
- These findings support the potential for safe application of folate-targeted therapies in cancer treatment.
