Involvement of Sirt1-FoxO3a-Bnip3 axis and autophagy mediated mitochondrial turnover in according protection to hyperglycemic NRK-52E cells by Berberine

• Published in: Toxicology in vitro 2024-10, Vol.100, p.105916, Article 105916
• Main Authors: Saxena, Sugandh, Anand, Sumit Kumar, Sharma, Ankita, Kakkar, Poonam
• Format: Article
• Language: English
• Subjects: Autophagy; Berberine; Diabetic nephropathy; Mitochondrial dysfunction; Mitophagy
• ISSN: 0887-2333; 1879-3177; 1879-3177
• DOI: 10.1016/j.tiv.2024.105916

Aberrant accumulation of dysfunctional mitochondria in renal cells during hyperglycemia signifies perturbed autophagy and mitochondrial turnover. This study aims to focus on the underlying mechanism involved in autophagy and mitophagy inducing efficacy of Berberine (isoquinoline alkaloid) in hyperglycemic NRK-52E cells. Berberine mediated protection to hyperglycemic cells prevented alteration in mitochondrial structure and function. Treatment with SRT-1720 (Sirt1 activator) enhanced autophagy, decreased apoptosis, upregulated expression of downstream moieties (FoxO3a and Bnip3) and ameliorated mitochondria related anomalies while nicotinamide (Sirt1 inhibitor) treatment exhibited reversal of the same. GFP reporter assay ascertained enhanced transcriptional activity of FoxO in Berberine-treated hyperglycemic cells, which was found to be correlated to increased expression of downstream protein Bnip3. Knocking down FoxO3a disrupted autophagy and stimulated apoptosis. N-acetyl-L-cysteine pre-treatment confirmed that generation of ROS intervened high glucose induced toxicity in NRK-52E cells. Berberine co-treatment resulted in differential expressions of key proteins involved in autophagy and mitophagy like LC3B, ATGs, Beclin1, Sirt1, Bnip3, FoxO3a and Parkin. Further, enhanced mitophagy in Berberine-treated cells was confirmed by transmission electron microscopy. Thus, our findings give evidence that the protection accorded by Berberine against hyperglycemia in renal proximal tubular cells (NRK-52E) involves instigation of Sirt1-FoxO3a-Bnip3 axis and autophagy mediated mitophagy induction. [Display omitted] •Berberine enhances autophagy via Sirt-1-FoxO3a-Bnip3 axis.•ROS mediates hyperglycemia induced renal toxicity by disrupting autophagy.•Berberine attenuates hyperglycemia induced mitochondrial dysfunction in NRK-52E cells.•Mitophagy is induced by berberine for the removal of dysfunctional mitochondria.