Specific BK Channel Activator NS11021 Protects Rat Renal Proximal Tubular Cells from Cold Storage-Induced Mitochondrial Injury In Vitro.
Kidneys from deceased donors used for transplantation are placed in cold storage (CS) solution during the search for a matched recipient. However, CS causes mitochondrial injury, which may exacerbate renal graft dysfunction. Here, we explored whether adding NS11021, an activator of the mitochondrial big-conductance calcium-activated K+ (mitoBK) channel, to CS solution can mitigate CS-induced mitochondrial injury. We used normal rat kidney proximal tubular epithelial (NRK) cells as an in vitro model of renal cold storage (18 h) and rewarming (2 h) (CS + RW). Western blots detected the pore-forming α subunit of the BK channel in mitochondrial fractions from NRK cells. The fluorescent K+-binding probe, PBFI-AM, revealed that isolated mitochondria from NRK cells exhibited mitoBK-mediated K+ uptake, which was impaired ~70% in NRK cells subjected to CS + RW compared to control NRK cells maintained at 37 °C. Importantly, the addition of 1 M NS11021 to CS solution prevented CS + RW-induced impairment of mitoBK-mediated K+ uptake. The NS11021-treated NRK cells also exhibited less cell death and mitochondrial injury after CS + RW, including mitigated mitochondrial respiratory dysfunction, depolarization, and superoxide production. In summary, these new data show for the first time that mitoBK channels may represent a therapeutic target to prevent renal CS-induced injury.
['Shrum|Stephen|S|', 'Rusch|Nancy J|NJ|', 'MacMillan-Crow|Lee Ann|LA|']
D000818:Animals D002460:Cell Line D015925:Cryopreservation D004847:Epithelial Cells D005786:Gene Expression Regulation D007687:Kidney Tubules, Proximal D051037:Large-Conductance Calcium-Activated Potassium Channel alpha Subunits D053078:Membrane Potential, Mitochondrial D008928:Mitochondria D008954:Models, Biological D051381:Rats D013777:Tetrazoles D013890:Thiourea
NS11021 kidney transplantation cold storage mitochondria mitoBK channel oxidative stress respiration