Abstract: TH-OR004
Enhanced Tubuloglomerular Feedback by Specific Deletion of Macula Densa NOS1 Enhances AKI by Activating Inflammatory and Fibrogenic Factors
Session Information
- AKI Progression and Resolution: Cellular and Molecular Insights
November 06, 2025 | Location: Room 320A, Convention Center
Abstract Time: 05:00 PM - 05:10 PM
Category: Acute Kidney Injury
- 103 AKI: Mechanisms
Authors
- Ni, Runze, University of South Florida Morsani College of Medicine, Tampa, Florida, United States
- Melaika, Miriame, University of South Florida Morsani College of Medicine, Tampa, Florida, United States
- Williams, Kristof, University of South Florida Morsani College of Medicine, Tampa, Florida, United States
- Li, Minghua, University of South Florida Morsani College of Medicine, Tampa, Florida, United States
- Hall, Nathan, University of South Florida Morsani College of Medicine, Tampa, Florida, United States
- Zhang, Jie, Boston University, Boston, Massachusetts, United States
- Wei, Jin, Boston University, Boston, Massachusetts, United States
- Wang, Lei, University of South Florida Morsani College of Medicine, Tampa, Florida, United States
- Hernandez Soto, Nohely, University of South Florida Morsani College of Medicine, Tampa, Florida, United States
- Bahena-López, Jessica Paola, Oregon Health & Science University, Portland, Oregon, United States
- McCormick, James A., Oregon Health & Science University, Portland, Oregon, United States
- Liu, Ruisheng, University of South Florida Morsani College of Medicine, Tampa, Florida, United States
Background
Acute kidney injury (AKI) reduces renal function, causing high morbidity and mortality. We previously showed that neuronal nitric oxide synthase (NOS1) influences nitric oxide (NO)-mediated dilation of the afferent arteriole, inhibiting tubule-glomerular feedback (TGF), which helps regulate renal hemodynamics and glomerular filtration rate (GFR). We explored the impact of NOS1 deletion in the macula densa on AKI progression.
Methods
We created a novel inducible NKCC2-Cre line, and crossed it with NOS1 flox/flox mice to create new macula densa-specific NOS1 knockout mice. AKI was induced by bilateral clamping renal pedicles for 18min at 37 °C. 48hr after reperfusion, we measured GFR, plasma creatinine and renin, histological injury, inflammation, apoptosis, and fibrosis. We first categorized the NKCC2-Cre line by crossing with a tomato flox line. The inducible NKCC2-Cre/tomato flox line was expressed only on NKCC2 expression tissues in the thick ascending limbs and macula densa cells. Crossing NKCC2-Cre line with NOS1 flox line induced a complete deletion of NOS1 from the macula densa cells, shown with IF double staining. TGF was measured in vitro with double perfusion of juxtaglomerular apparatus.
Results
Deletion of macula densa NOS1 enhanced TGF response (3.12 ± 0.3 µm in control vs 4.86 ± 0.5 µm in KO). In response to IRI, NOS1 knockouts exhibited enhanced AKI, marked by lower GFR (236 ± 66 to 24 ± 22 µL/min), higher plasma creatinine levels (0.75 ± 1.14 to 2.26 ± 0.4 mg/dl), and elevated renin (747.31 ± 283.69 to 1022.33 ± 211.06 ng/mL), alongside enhanced tubular damage, evidenced by H&E staining. Cytokine array analysis showed most cytokine levels were unaffected, but chemokines such as MCP-1, CXCL1, and macrophage marker CD68 were increased. Western blot analysis showed cleaved caspase-3 levels were increased, indicating increased apoptosis. Fibrosis markers TIMP1, collagen-3, and α-SMA were also upregulated at both mRNA and protein levels.
Conclusion
Enhanced TGF response by deleting macula densa NOS1 exacerbates AKI by enhancing inflammatory and fibrogenic factors, highlighting the role of NOS1 in AKI pathophysiology. Targeting NOS1 could be a therapeutic strategy for AKI.
Funding
- NIDDK Support