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Updated: Feb 26, 2026
Modeling Hypoxia/Reoxygenation Injury in Proximal Tubular Epithelial Cells
Published on: November 21, 2025
Heat shock protein 70/nitric oxide effect on stretched tubular epithelial cells linked to WT-1 cytoprotection during
Luciana Mazzei1,2, Fernando Darío Cuello-Carrión1, Neil Docherty3
1Laboratorio de Farmacología Experimental Básica y Traslacional. IMBECU-CONICET (National Council of Scientific and Technical Research of Argentina), Buenos Aires, Argentina.
Background:
Mechanical stress is a key pathogenic driver of apoptosis in the tubular epithelium in obstructive nephropathy. Heat shock protein 70 (Hsp70) and Wilms' tumor (WT-1) have been proposed to represent linked downstream effectors of the cytoprotective properties of NO. In the present study, we sought to evaluate whether the cytoprotective effects of L-arginine in neonatal obstructive nephropathy may be associated with NO-dependent increases in WT-1 and Hsp70 expression.
Methods:
Neonatal Wistar-Kyoto rats were submitted to complete unilateral ureteral obstruction (UUO) and treated thereafter with vehicle, L-NAME or L-arginine by daily gavage for 14 days to block or augment NO levels, respectively. Normal rat kidney epithelial cells by NRK-52E were exposed to mechanical stress in vitro in the presence or absence of L-NAME, L-arginine, sodium nitroprusside (SNP), L-arginine + SNP or L-arginine/L-NAME. Induction of apoptosis and the mRNA expression of WT-1 and Hsp70 genes were assessed.
Results:
WT-1 and Hsp70 genes expression decreased in the presence of L-NAME and following UUO coincident with increased tubular apoptosis. L-arginine treatment increased NO levels, reduced apoptosis and restored expression levels of WT-1 and Hsp70 to control levels. L-arginine treatment in vitro reduced basal apoptotic rates and prevented apoptosis in response to mechanical strain, an effect enhanced by SNP co-incubation. L-NAME increased apoptosis and prevented the anti-apoptotic action of L-arginine.
Conclusions:
L-arginine treatment in experimental neonatal UUO reduces apoptosis coincident with restoration of WT-1 and Hsp70 expression levels and directly inhibits mechanical strain-induced apoptosis in an NO-dependent manner in vitro. This potentially implicates an NO-Hsp70-WT-1 axis in the cytoprotective effects of L-arginine.
Insights
L-arginine protects against kidney injury by reducing apoptosis and restoring protective proteins WT-1 and Hsp70. This effect is nitric oxide (NO)-dependent, suggesting a novel therapeutic pathway for obstructive nephropathy.
Area of Science:
- Nephrology
- Molecular Biology
- Cell Biology
Background:
- Mechanical stress is a key factor in tubular apoptosis in obstructive nephropathy.
- Heat shock protein 70 (Hsp70) and Wilms' tumor 1 (WT-1) are linked to nitric oxide's (NO) cytoprotective effects.
- The study investigates L-arginine's role in NO-dependent WT-1 and Hsp70 expression.
Purpose of the Study:
- To evaluate if L-arginine's protective effects in neonatal obstructive nephropathy involve NO-dependent increases in WT-1 and Hsp70.
- To assess the impact of L-arginine and NO modulation on tubular apoptosis and gene expression in vitro and in vivo.
Main Methods:
- Neonatal rats underwent unilateral ureteral obstruction (UUO) and received vehicle, L-NAME (NO blocker), or L-arginine (NO enhancer).
- Kidney epithelial cells were exposed to mechanical stress with or without L-NAME, L-arginine, or sodium nitroprusside (SNP).
- Apoptosis and mRNA expression of WT-1 and Hsp70 were measured.
Main Results:
- UUO and L-NAME increased tubular apoptosis and decreased WT-1/Hsp70 expression.
- L-arginine treatment reduced apoptosis and restored WT-1/Hsp70 levels in UUO rats.
- In vitro, L-arginine and SNP reduced mechanical stress-induced apoptosis, while L-NAME exacerbated it.
Conclusions:
- L-arginine reduces apoptosis in neonatal obstructive nephropathy by restoring WT-1 and Hsp70 expression via an NO-dependent mechanism.
- L-arginine directly inhibits mechanical strain-induced apoptosis in kidney cells in an NO-dependent manner.
- An NO-Hsp70-WT-1 axis is implicated in L-arginine's cytoprotective actions.
