Icariin Treatment Protects Against Gentamicin-Induced Ototoxicity via Activation of the AMPK-SIRT3 Pathway

Abstract

Ototoxicity is a serious health problem that greatly affects millions of people worldwide. This condition is caused by the entry of aminoglycosides into auditory hair cells, subsequently inducing reactive oxygen species (ROS) production and accumulation. Several strategies have been adopted to overcome irreversible ROS-induced hair cell loss in mammals. In recent years, icariin, a major active component of the traditional herb Epimedium, has been widely studied and revealed to have antioxidant, anti-inflammatory, and anti-apoptotic properties. In this study, we found that icariin pretreatment improved the survival rate of gentamicin-treated House Ear Institute-Organ of Corti 1 (HEI-OC1) cells and cochlear explants. Icariin remarkably suppressed HEI-OC1 cell apoptosis and inhibited ROS production in cells. Notably, icariin upregulated PGC-1α (SIRT3 promoter) and SIRT3 expression in HEI-OC1 cells. In addition, SIRT3 inhibition significantly attenuated the anti-apoptotic effect of icariin. We also found that icariin can increase AMPK phosphorylation. Further studies showed that inhibition of SIRT3 activity had no significant effect on AMPK phosphorylation. Furthermore, the AMPK inhibitor compound C significantly suppressed SIRT3 expression, meaning that AMPK, as an upstream molecule, regulates SIRT3 expression. Meanwhile, inhibition of AMPK activity significantly reduced the protective effect of icariin on gentamicin ototoxicity. Based on these results, icariin exerts its protective effect on gentamicin-induced ototoxicity via activation of the AMPK-SIRT3 signaling pathway, thus providing a new strategy for treating ototoxicity caused by aminoglycoside antibiotics.

Mitochondrial sirtuin 3 and various cell death modalities

“…Sirt3 activation by the small-molecule compound 33c (ADTL-SA1215) induced mitophagy and inhibited proliferation and migration in human breast carcinoma cells (Zhang et al, 2021a). The Nrf2/Sirt3 pathway promoted mitophagy, preventing nucleus pulpous apoptosis during intervertebral disc degeneration (Hu et al, 2021). These studies show that Sirt3-mediated mitophagy is involved in apoptosis suppression and regulates cell survival and death.…”

“…Interestingly, Sirt3 also can negatively regulate autophagy in the liver through ROS-mediated AMPK-mTORC1-autophagy pathway suppression and downregulation of MAP1LC3 expression (Li et al, 2017). However, novel data demonstrate that AMPK can act as an upstream Sirt3 regulator (Hu and Ma, 2021;Wang et al, 2021;Li et al, 2022). Additionally, Sirt3 can influence mTOR via the PI3K/Akt pathway.…”

Icariin protects cerebral neural cells from ischemia‑reperfusion injury in an in vitro model by lowering ROS production and intracellular calcium concentration

“…Hypoxic postconditioning has also been attempted to reduce the cell loss since a hypoxic postconditioning containing three cycles of 5 min of reoxygenation and 5 min of rehypoxia applied before 6 h of reoxygenation reduces ROS generation, cardiomyocyte death and mitochondrial Ca 2+ overload (56). However, SOD activity was not changed after ICA treatment, implying that other mechanisms including lipid synthesis de novo and prevention of lipid oxidation may be involved in the reduced cell death, likely including reduced production of ROS (57,58), which is main cause of lipid peroxidation (59).…”

“…For example, ICA may regulate Nrf2 to generate antioxidant response, as observed in porcine oocyte (57) and further studies are needed to investigate whether ICA activates Nrf2 signaling to generate antioxidant activity. In addition, ICA was shown to activate AMPK-SIRT3 signaling pathway, and it may mitigate the antioxidant activity via mitochondrial ROS homeostasis by AMPK-SIRT3 signaling pathway (58).…”

Based on network pharmacology and molecular docking to explore the protective effect of Epimedii Folium extract on cisplatin-induced intestinal injury in mice

“…Cisplatin treatment significantly increased the expression of Bax and inhibited the expression of Bcl-2. Studies have shown that flavonoids extracted from Epimedii Folium can exert anti-apoptotic effects by increasing the ratio of Bcl-2/Bax and reducing the expression of caspase 3 ( Liu et al, 2014 ; Hu and Ma, 2021 ). Our results also showed that EFE alleviated cisplatin-induced apoptosis by downregulating Bax expression, upregulating Bcl-2 expression, reducing caspase-9 and caspase-3 expression, and cytochrome c release.…”