Abstract: SA-PO0494
Human Kidney Organoids Exhibit Intrinsic Capacity to Biosynthesize Cholesterol and Estrogen
Session Information
- Fluid, Electrolyte, and Acid-Base Disorders: Basic Research
November 08, 2025 | Location: Exhibit Hall, Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Fluid, Electrolytes, and Acid-Base Disorders
- 1101 Fluid, Electrolyte, and Acid-Base Disorders: Basic
Authors
- Kiyimba, Frank, Vanderbilt University Medical Center, Nashville, Tennessee, United States
- Bejoy, Julie, Vanderbilt University Medical Center, Nashville, Tennessee, United States
- Woodard, Lauren Elizabeth, Vanderbilt University Medical Center, Nashville, Tennessee, United States
- Gohar, Eman Y., Vanderbilt University Medical Center, Nashville, Tennessee, United States
Group or Team Name
- Gohar Lab.
Background
The kidney plays a central role in blood pressure and sodium homeostasis. Renal estrogenic signaling enhances sodium excretion and lowers blood pressure. While estrogen biosynthesis has been demonstrated in rodent kidneys, the endogenous capacity in the human kidney remains unclear. Given that cholesterol is a key precursor for estrogen synthesis, we hypothesized that human kidney organoids derived from induced pluripotent stem cells (iPSC) possess intrinsic cholesterol biosynthetic capacity to support local estrogen production.
Methods
We analyzed publicly available RNA-seq datasets from day 26 human kidney organoids for key cholesterol biosynthesis genes and identified transcripts for 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR), the rate-limiting enzyme in cholesterol biosynthesis and its upstream transcriptional regulator SREBP2. To validate these findings, we differentiated kidney organoids from iPSC on transwells using the Takasato protocol in vitro. We collected culture media at days 10, 12, 15 (n=4 per time point, pooled from two independent batches). We performed immunofluorescence at days 17 and 19 to localize expression of HMGCR, CYP11A1, which catalyzes the conversion of cholesterol to pregnenolone, and aromatase (CYP19A1), which catalyzes the rate limiting step in estrogen biosynthesis. We quantified cholesterol and 17-β estradiol levels in culture media using the Amplex Red assay and ELISA, respectively.
Results
In-silico analyses revealed expression of HMGR and SREBP2 in day 26 organoids. We confirmed HMGCR co-localization with the LTL-positive proximal tubule-like structures, while CYP11A1 and CYP19A1 localized to ECADHERIN-positive tubular regions. We validated HMGCR protein expression by Western blot, corroborating the transcriptomic and immunofluorescence data. Biochemical analysis showed increases in total cholesterol (day 12 vs 10, p=0.04), free cholesterol (day 15 vs 10, p = 0.03) and 17-β estradiol (day 15 vs control media, p=0.04).
Conclusion
We demonstrate that human iPSC-derived kidney organoids have functional cholesterol biosynthesis and temporally regulated estrogen production, supporting a model in which locally synthesized cholesterol may contribute to local estrogenesis. Further investigations are needed to elucidate the role of renal steroidogenesis in regulating natriuresis and blood pressure.
Funding
- NIDDK Support