Objective:To investigate the protective effects of gypenoside XVII(GP-17)against cisplatin-induced acute kidney injury and to elucidate whether its mechanism involves the activation of PINK1/Parkin-mediated mitophagy....Objective:To investigate the protective effects of gypenoside XVII(GP-17)against cisplatin-induced acute kidney injury and to elucidate whether its mechanism involves the activation of PINK1/Parkin-mediated mitophagy.Methods:Sprague-Dawley rats were randomly divided into four groups:control,cisplatin,cisplatin+GP-17,and GP-17 alone.Cisplatin was administered intraperitoneally at 20 mg/kg to induce acute kidney injury,while GP-17 was given orally at 40 mg/kg/day for 7 d.The levels of serum creatinine and blood urea nitrogen,superoxide dismutase activity,and malondialdehyde content were measured.Histopathological analysis and transmission electron microscopy were also performed to evaluate the effects of GP-17 on renal injury.Moreover,the expression of mitophagy-related proteins,including PINK1,Parkin,LC3,and p62,and the mRNA expression of inflammatory markers were determined by Western blot and quantitative RT-PCR assays.Furthermore,human renal tubular epithelial HK-2 cells were treated with cisplatin and GP-17,with or without PINK1 siRNA transfection.Cell viability,apoptosis,reactive oxygen species levels,mitochondrial membrane potential,and the protein expression associated with the PINK1/Parkin pathway were measured.Results:In rats with cisplatin-induced acute kidney injury,GP-17 significantly ameliorated cisplatin-induced elevations in serum creatinine and blood urea nitrogen,attenuated tubular damage and mitochondrial ultrastructural injury,and reduced oxidative stress by increasing superoxide dismutase activity and decreasing malondialdehyde content.GP-17 further upregulated the protein levels of PINK1,Parkin,and LC3-Ⅱ/Ⅰratio while promoting p62 degradation,indicating enhanced mitophagic flux.In HK-2 cells,GP-17(20μM)co-treatment markedly attenuated cisplatin-induced cytotoxicity,apoptosis,reactive oxygen species overproduction,and mitochondrial depolarization.However,all these protective effects of GP-17 were completely abolished upon PINK1 knockdown.Conclusions:GP-17 protects against cisplatin-induced nephrotoxicity by activating PINK1/Parkin-mediated mitophagy,which facilitates the clearance of damaged mitochondria,alleviates oxidative stress,and inhibits renal cell apoptosis.These findings identify GP-17 as a promising candidate for mitigating chemotherapy-induced acute kidney injury.展开更多
The vast majority of in vitro studies have demonstrated that PINK1 phosphorylates Parkin to work together in mitophagy to protect against neuronal degeneration.However,it remains largely unclear how PINK1 and Parkin a...The vast majority of in vitro studies have demonstrated that PINK1 phosphorylates Parkin to work together in mitophagy to protect against neuronal degeneration.However,it remains largely unclear how PINK1 and Parkin are expressed in mammalian brains.This has been difficult to address because of the intrinsically low levels of PINK1 and undetectable levels of phosphorylated Parkin in small animals.Understanding this issue is critical for elucidating the in vivo roles of PINK1 and Parkin.Recently,we showed that the PINK1 kinase is selectively expressed as a truncated form(PINK1–55)in the primate brain.In the present study,we used multiple antibodies,including our recently developed monoclonal anti-PINK1,to validate the selective expression of PINK1 in the primate brain.We found that PINK1 was stably expressed in the monkey brain at postnatal and adulthood stages,which is consistent with the findings that depleting PINK1 can cause neuronal loss in developing and adult monkey brains.PINK1 was enriched in the membrane-bound fractionations,whereas Parkin was soluble with a distinguishable distribution.Immunofluorescent double staining experiments showed that PINK1 and Parkin did not colocalize under physiological conditions in cultured monkey astrocytes,though they did colocalize on mitochondria when the cells were exposed to mitochondrial stress.These findings suggest that PINK1 and Parkin may have distinct roles beyond their well-known function in mitophagy during mitochondrial damage.展开更多
基金supported by grants from the Health Commission of Zigong High-Level Talent Development Project(WJW-GCCRC007).
文摘Objective:To investigate the protective effects of gypenoside XVII(GP-17)against cisplatin-induced acute kidney injury and to elucidate whether its mechanism involves the activation of PINK1/Parkin-mediated mitophagy.Methods:Sprague-Dawley rats were randomly divided into four groups:control,cisplatin,cisplatin+GP-17,and GP-17 alone.Cisplatin was administered intraperitoneally at 20 mg/kg to induce acute kidney injury,while GP-17 was given orally at 40 mg/kg/day for 7 d.The levels of serum creatinine and blood urea nitrogen,superoxide dismutase activity,and malondialdehyde content were measured.Histopathological analysis and transmission electron microscopy were also performed to evaluate the effects of GP-17 on renal injury.Moreover,the expression of mitophagy-related proteins,including PINK1,Parkin,LC3,and p62,and the mRNA expression of inflammatory markers were determined by Western blot and quantitative RT-PCR assays.Furthermore,human renal tubular epithelial HK-2 cells were treated with cisplatin and GP-17,with or without PINK1 siRNA transfection.Cell viability,apoptosis,reactive oxygen species levels,mitochondrial membrane potential,and the protein expression associated with the PINK1/Parkin pathway were measured.Results:In rats with cisplatin-induced acute kidney injury,GP-17 significantly ameliorated cisplatin-induced elevations in serum creatinine and blood urea nitrogen,attenuated tubular damage and mitochondrial ultrastructural injury,and reduced oxidative stress by increasing superoxide dismutase activity and decreasing malondialdehyde content.GP-17 further upregulated the protein levels of PINK1,Parkin,and LC3-Ⅱ/Ⅰratio while promoting p62 degradation,indicating enhanced mitophagic flux.In HK-2 cells,GP-17(20μM)co-treatment markedly attenuated cisplatin-induced cytotoxicity,apoptosis,reactive oxygen species overproduction,and mitochondrial depolarization.However,all these protective effects of GP-17 were completely abolished upon PINK1 knockdown.Conclusions:GP-17 protects against cisplatin-induced nephrotoxicity by activating PINK1/Parkin-mediated mitophagy,which facilitates the clearance of damaged mitochondria,alleviates oxidative stress,and inhibits renal cell apoptosis.These findings identify GP-17 as a promising candidate for mitigating chemotherapy-induced acute kidney injury.
基金supported by the National Natural Science Foundation of China,Nos.32070534(to WY),32370567(to WY),82371874(to XL),81830032(to XL),82071421(to SL)Key Field Research and Development Program of Guangdong Province,No.2018B030337001(to XL)+2 种基金Guangzhou Key Research Program on Brain Science,No.202007030008(to XL)Department of Science and Technology of Guangdong Province,Nos.2021ZT09Y007,2020B121201006(to XL)Guangdong Basic and Applied Basic Research Foundation,Nos.2022A1515012301(to WY),2023B1515020031(to WY).
文摘The vast majority of in vitro studies have demonstrated that PINK1 phosphorylates Parkin to work together in mitophagy to protect against neuronal degeneration.However,it remains largely unclear how PINK1 and Parkin are expressed in mammalian brains.This has been difficult to address because of the intrinsically low levels of PINK1 and undetectable levels of phosphorylated Parkin in small animals.Understanding this issue is critical for elucidating the in vivo roles of PINK1 and Parkin.Recently,we showed that the PINK1 kinase is selectively expressed as a truncated form(PINK1–55)in the primate brain.In the present study,we used multiple antibodies,including our recently developed monoclonal anti-PINK1,to validate the selective expression of PINK1 in the primate brain.We found that PINK1 was stably expressed in the monkey brain at postnatal and adulthood stages,which is consistent with the findings that depleting PINK1 can cause neuronal loss in developing and adult monkey brains.PINK1 was enriched in the membrane-bound fractionations,whereas Parkin was soluble with a distinguishable distribution.Immunofluorescent double staining experiments showed that PINK1 and Parkin did not colocalize under physiological conditions in cultured monkey astrocytes,though they did colocalize on mitochondria when the cells were exposed to mitochondrial stress.These findings suggest that PINK1 and Parkin may have distinct roles beyond their well-known function in mitophagy during mitochondrial damage.
