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Abstract: SA-PO092

Overexpression of MIOX Accentuates Gentamycin-Induced Acute Tubular Injury via ALOX12-12HETE-GPR31 Signaling

Session Information

Category: Acute Kidney Injury

  • 103 AKI: Mechanisms

Authors

  • Sharma, Isha, Northwestern University Medical School, Chicago, Illinois, United States
  • Deng, Fei, Northwestern University Medical School, Chicago, United States
  • Liao, Yingjun, Northwestern University Medical School, Chicago, United States
  • Kanwar, Yashpal S., Northwestern University Medical School, Chicago, Illinois, United States
Background

Myo-inositiol oxygenase (MIOX), a renal tubular enzyme, has been implicated in the pathogenesis of high glucose and cisplatin induced tubular injury. Gentamycin is an aminoglycoside antibiotic used clinically, and it is known for its nephrotoxic effects. The mechanism(s) for its nephrotoxicity are somewhat elusive

Methods

In the present investigation, we identified a novel signaling pathway, i.e., arachidonate 12-lipoxygenase (ALOX12)–12-hydroxyeicosatetraenoic acid (12-HETE) G-protein-coupled receptor 31 (GPR31) axis, relevant to gentamycin induced tubular injury. Wild type (WT), MIOX overexpressing (MIOX-TG) and MIOX knockout (MIOX-KO) mice received daily intraperitoneal injections of gentamycin (100 mg/kg) for seven days. The following day animals were sacrificed, and their urine, blood and kidney samples were collected for various studies

Results

We observed that gentamycin-treated MIOX-TG mice had relatively high serum creatinine levels and increased albuminuria compared to WT mice, whereas MIOX-KO mice had minimal increase in serum creatinine and no detectable albuminuria. Interestingly, the increased ROS generation induced by gentamycin promoted the expression of MIOX via ROS modulation, leading to accentuated lipid peroxidation. Arachidonic acid, a fatty acid present abundantly in renal tubules, which is metabolized into 12-HETE by ALOX-12, leading to acute inflammatory response under various pathologic conditions. We observed significant increase in ALOX-12 expression and 12-HETE production in gentamycin-treated MIOX-TG and WT mice. These perturbations were minimally seen in gentamycin-treated MIOX-KO mice. MIOX gene disruption in HK-2 cells abolished gentamycin induced cascade of inflammatory signaling events (p-p44/42, p-pERK, p-p38, p-pJNK, p-Nf-kB). Of note, the gentamycin-induced up-regulated 12-HETE binds with GPR-31 to accentuate the inflammatory response in renal tubules, which was attenuated by ML-355 (inhibitor of ALOX-12).

Conclusion

Collectively, these studies highlight a novel mechanism, i.e., ALOX12-12-HETE-GPR31 signaling axis, in the pathogenesis of gentamycin-induced nephrotoxicity modulated by MIOX.

Funding

  • NIDDK Support