Kidney Week

Abstract: TH-PO0549

Kidney-Specific Mouse Model to Study the Effects of In Vivo Induction of Yamanaka Factors

Session Information

• Development, Stem Cells, and Regenerative Medicine
  November 06, 2025 | Location: Exhibit Hall, Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Development, Stem Cells, and Regenerative Medicine

• 600 Development, Stem Cells, and Regenerative Medicine

Authors

• Franken, Gijs AC, Boston Children's Hospital, Boston, Massachusetts, United States

Gijs AC Franken, MS, MSc, PhD

• Lemberg, Katharina, Boston Children's Hospital, Boston, Massachusetts, United States

Katharina Lemberg, MD

• Riedhammer, Korbinian M., Boston Children's Hospital, Boston, Massachusetts, United States

Korbinian M. Riedhammer, MD

• Hölzel, Selina, Boston Children's Hospital, Boston, Massachusetts, United States

Selina Hölzel

• Yousef, Kirollos, Boston Children's Hospital, Boston, Massachusetts, United States

Kirollos Yousef, MBChB, MS

• Kalkar, Gina S, Boston Children's Hospital, Boston, Massachusetts, United States

Gina S Kalkar

• Lomjansook, Kraisoon, Boston Children's Hospital, Boston, Massachusetts, United States

Kraisoon Lomjansook, MD

• Kolvenbach, Caroline Maria, Boston Children's Hospital, Boston, Massachusetts, United States

Caroline Maria Kolvenbach, MD, DrMed

• Saida, Ken, Boston Children's Hospital, Boston, Massachusetts, United States

Ken Saida, MD, PhD

• Buerger, Florian, Boston Children's Hospital, Boston, Massachusetts, United States

Florian Buerger, MD, PhD

• Hildebrandt, Friedhelm, Boston Children's Hospital, Boston, Massachusetts, United States

Friedhelm Hildebrandt, MD

Background

Transgenic expression of the four Yamanaka factors (YF) Oct4, Klf4, Sox2, and c-Myc can reprogram somatic cells towards pluripotency in vitro. Studies demonstrated phenotypic amelioration after injury upon ectopic YF-induction in vivo. Here, we describe a kidney-specific mouse model allowing us to study the effects of YF-induction in a kidney injury model.

Methods

tetOP-OKSmC mice (JAX: 034917) were crossed with OKMSCh250 (JAX:031012) and Pax8^Cre mice (JAX: 028196) to obtain OKSmC^tg/--rtTA^fl/--Pax8Cre^tg/- or Pax8Cre^-/- mice. YF induction was achieved by supplementing drinking water with 1-2 mg/mL doxycycline (dox) for 1-7 days. To induce kidney injury, mice were injected i.p. with 7.5 µg/kg aristolochic acid (AA). Kidneys were collected directly or one month after dox exposure for gene expression studies by qPCR and immunofluorescence. To assess AA-induced injury and the potential amelioration via YF induction, injury markers were analyzed via qPCR and blood chemistry, and kidneys were stained with Masson's trichrome (MT).

Results

Exposure to 1 mg/mL dox increased expression of Oct4 in kidney tissue in Pax8Cre^tg/- mice in time, compared to controls, with highest expression at day 3 (200.4-fold ± 18.3), which was decreased at day 7 (47.9-fold ± 13.5). This pattern was similar for the other YF-transgenes. Co-staining for Sox2 and megalin in whole kidney tissue revealed that 14.3% ± 1.1 of cells were Sox2⁺-megalin⁺, while 1.0% ± 0.1 of cells were Sox2⁺-megalin^-. Mice receiving dox for 5 days developed tumors throughout the kidney. To investigate whether YF induction could ameliorate kidney injury, Pax8Cre^tg/- and Pax8Cre^-/- mice received AA on the second of a 3-day dox exposure. After one month, the BUN was increased in both Pax8Cre^tg/- and Pax8Cre^-/- mice, which was concomitant with fibrosis based on MT staining and Fn1 expression. Kidney injury markers Kim1 and Ngal were increased in both groups receiving AA.

Conclusion

In conclusion, OKSmC^tg/--rtTA^fl/--Pax8Cre^tg/- mice showed YF expression in proximal tubular cells. Elongated induction of YF resulted in tumor formation, suggesting induced pluripotency despite the absence of the fourth YF c-Myc. Short-term YF-induction did not result in amelioration upon AA-induced kidney injury.

Funding

• Other NIH Support

Digital Object Identifier (DOI)

• doi: 10.1681/ASN.2025ffvdcx9c