Mitochondria Functional Study in Cisplatin-Induced AKI

Background: Acute kidney injury (AKI) results from a generalized or localized impairment of oxygen and nutrient delivery to the kidney. As a result of this imbalance, the tubular epithelial cells undergo injury, which manifests as cell death by apoptosis and necrosis, with reduced kidney function, impaired water and electrolyte homeostasis, and reduced excretion of waste products of metabolism. Administration of the chemotherapeutic agent cisplatin leads to acute kidney injury (AKI). Cisplatin-induced AKI (CIAKI) has a complex pathophysiological map, which has been linked to apoptosis, oxidative and stress. objective:Since the pathophysiology of AKI is reflected in mitochondrial function dysregulation, we aim to examine the role of mitochondria in the Cisplatin model of AKI in kidney tubular cells at different time points Methods: We isolated tubular cells from Pham mice. The cell’s mitochondria are tagged with Dendra2 (mito-Dendra2), a photo-convertible fluorescent protein, which enables us to examine the fission-fusion events in response to stimuli Results: The confocal microscopy shows that upon treatment of the cells with cis-platin, mitochondria were more fragmented and profoundly affected photobleaching. The mitochondrial movement was significantly reduced as compared to untreated control, and the stress was delayed. The genes corresponding to mitochondrial function were analyzed by qPCR. It was interesting to find that the genes related to mitochondrial functionalities (COXI) and biogenesis (PGC1a) were upregulated in 12hr treatment with cisplatin; however, cells treated with cisplatin for 24hrs had increased oxidative stress (~2 folds). It was observed that the mitochondria biogenesis genes were drastically reduced in 24-hour treatment. Further, ALCLAT-1, a gene that promotes autophagy, was upregulated, indicating that the cells try to negate the stress due to cisplatin treatment; however, prolonged treatment reduces the transcriptional activity. Conclusion: Our preliminary results suggest that cisplatin treatment leads to compromised mitochondrial functions and increased oxidative stress. Funding: NIDDK Support