Assessment of Mitochondria Dynamics in Cisplatin AKI Mouse Model

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. 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, examine the sex dimorphism of mitochondria dynamics and metabolism in response to cisplatin 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. We measured cellular metabolic function using seahorse assay and examined cellular proliferation and apoptosis. Results: The confocal microscopy shows that upon treatment of the cells with cisplatin, mitochondria were more fragmented and profoundly affected photobleaching in cells from male mice as compared to cell isolated from female mice. The mitochondrial movement was significantly reduced as compared to untreated control. 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 in cells isolated from male and female. 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. The cellular metabolic function activity, cell proliferation showed significant decrease in male cells besides increase in apoptosis. We compared the results among male and female mice to assess the role of genetic or non-genetic factors for differences. . Conclusion: Our preliminary results suggest that cisplatin treatment leads to significantly increased compromised mitochondrial dynamics and functions in cells isolated from males as compared to cells from female mice. Funding: NIDDK Support