Resveratrol exerts different effects on renal epithelial cells depending on media osmolality.

CASALI, CECILIA IRENE; RECABARREN, MANUEL; FAVALE, NICOLÁS; PARRA, LEANDRO GASTÓN; TULINO, MARÍA SOLEDAD; CARBALLO, MARTA; ERJAVEC, LUCIANA CECILIA; SENDYK, DYLAN E.; LÓPEZ NIGRO, MARCELA; FERNÁNDEZ TOME, MARIA DEL CARMEN

Rosario

Congreso; LIV Reunión de la Sociedad Argentina de Investigaciones Bioquímicas y Biología Molecular- SAIB 2023; 2023

Sociedad Argentina de Investigaciones Bioquímicas y Biología Molecular-SAIB

Resveratrol (RSV) is a polyphenol naturally present in several plants. Nowadays it is sold as anover-the-counter dietary supplement due to its antioxidant, anti-inflammatory and antitumoral effects.Paradoxically, it was proven that RSV may also present pro-oxidizing and pro-proliferative effects.Likewise, RSV effects on renal tissue are still controversial, as some injury models described beneficialeffects, while others observed nephrotoxicity, without apparent cause. Renal medullary interstitiumpresents an elevated osmolality due to sodium and urea accumulation. Depending on the hydric stateof the body, this osmolality can abruptly vary, reaching values up to 800-1200 mOsm/kg H2O. Initially,cells activate protective mechanisms to survive in such an adverse environment, but then this highosmolality is also a physiological signal for cell differentiation. We demonstrated that the renal epithelialcell line MDCK undergoes an adaptive process during the first 24h of hyperosmolarity, and after 48hcells are already adapted and begin to differentiate, acquiring a polarized morphology. Considering thecontroversial effects of RSV in the kidney, in this work we evaluate RSV effect both on cells cultured inisosmolality or subjected to physiological hyperosmolarity, particularly on osmoadaptation anddifferentiation mechanisms. MDCK cells were pretreated with different concentrations of RSV (1-25 μM)and then cultured in isosmolar (ISO, ~298 mOsm/kg H2O) or hyperosmolar media (HYPER, ~512mOsm/kg H2O) for 24 and 48h. Cells were counted to obtain cell number. Viability using neutral redassay, cell cycle, DNA damage through comet assay, immunofluorescence (IF), western blot and qPCRanalysis were performed. We found that RSV significantly reduced cell number and viability inconcentration-dependent manner after 24 and 48h in HYPER, but not in ISO cells. Cell cycle analysisrevealed that RSV increased S-phase and sub-G0 population in HYPER, but not in ISO cells. Comet assayshowed a significant increase in DNA damage with 25 μM RSV in HYPER cells, which can be associatedwith the S-phase arrest; in this condition PARP cleavage was also higher, explaining the increase insub-G0 apoptotic population. Additionally, RSV-treated HYPER cells did not attain typical epitheliummorphology; instead, high RSV concentrations induced a mesenchymal phenotype. IF showed that RSVincreased cytoplasmic accumulation of E-cadherin and β-catenin nuclear translocation inconcentration-dependent manner. RSV treatment significantly increased mRNA expression of mesenchymal genes (N-cadherin, α-SMA) and decreased E-cadherin mRNA expression in HYPER cells,supporting the previous results. Our results suggest that RSV concentrations higher than 5 μM exertsignificant toxic effects on renal cells exposed to physiological hyperosmolarity, but not on cells culturedin isosmolar media. These results can contribute to explain RSV controversial effects in different renalmodels.