OBJECTIVE Activation of the PINK1/Parkin-mediated autophagy pathway has been proposed to play a protective role in the development of neurological disorders through the elimination of damaged macromolecules or organel...OBJECTIVE Activation of the PINK1/Parkin-mediated autophagy pathway has been proposed to play a protective role in the development of neurological disorders through the elimination of damaged macromolecules or organelles.Exposure to excessive manganese(Mn) causes neurotoxicity and can produce a Parkinson disease(PD)-like neurological disorder.Mitochondrial dysfunction and oxidative stress are implicated in the mechanism of Mn induced neurotoxicity.The present study was designed to determine whether Dendrobium nobile Lindl.alkaloids(DNLA),a Chinese medicinal herb extract,confers protective function over Mn-induced cell toxicity,and to investigate whether the modulation of PINK1/Parkin-mediated autophagy is involved in the mechanism of DNLA-mediated cell protection over Mn toxicity.METHODS AND RESULTS Rat adrenal pheochromocytoma PC12 cells were utilized as an in vitro model of Mn cell toxicity.It was found that the treatment of the PC12 cells with Mn resulted in concentration-dependent cell death,accompanied by a decrease in mitochondrial respiration capacity and an increase in ROS generation,whereas pretreatment of cells with DNLA significantly alleviated cell toxicity induced by Mn and improved mitochondrial function and oxidative status.Mn treatment enhanced apoptotic cells along with a marked increase in the protein expression of Bax and a decrease in the expression of Bcl-2 protein.On the contrary,DNLA increased Bcl-2 expression,and concomitantly dramatically decreased the Bax/Bcl-2 ratio.Analysis of the expression of PINK1 and Parkin revealed that pretreatment of cells with DNLA significantly alleviated the decrease in protein levels of both PINK1 and Parkin caused by Mn.Furthermore,cells treated with Mn exhibited increased expression of LC3-Ⅱ and a decrease in accumulation of P62,which was noticeably reversed by the pretreatment of cells with DNLA.CONCLUSION DNLA inhibits Mn induced cytotoxicity,which may be mediated through modulating PINK1/Parkin-mediated autophagic flux and improving mitochondrial function.展开更多
文摘OBJECTIVE Activation of the PINK1/Parkin-mediated autophagy pathway has been proposed to play a protective role in the development of neurological disorders through the elimination of damaged macromolecules or organelles.Exposure to excessive manganese(Mn) causes neurotoxicity and can produce a Parkinson disease(PD)-like neurological disorder.Mitochondrial dysfunction and oxidative stress are implicated in the mechanism of Mn induced neurotoxicity.The present study was designed to determine whether Dendrobium nobile Lindl.alkaloids(DNLA),a Chinese medicinal herb extract,confers protective function over Mn-induced cell toxicity,and to investigate whether the modulation of PINK1/Parkin-mediated autophagy is involved in the mechanism of DNLA-mediated cell protection over Mn toxicity.METHODS AND RESULTS Rat adrenal pheochromocytoma PC12 cells were utilized as an in vitro model of Mn cell toxicity.It was found that the treatment of the PC12 cells with Mn resulted in concentration-dependent cell death,accompanied by a decrease in mitochondrial respiration capacity and an increase in ROS generation,whereas pretreatment of cells with DNLA significantly alleviated cell toxicity induced by Mn and improved mitochondrial function and oxidative status.Mn treatment enhanced apoptotic cells along with a marked increase in the protein expression of Bax and a decrease in the expression of Bcl-2 protein.On the contrary,DNLA increased Bcl-2 expression,and concomitantly dramatically decreased the Bax/Bcl-2 ratio.Analysis of the expression of PINK1 and Parkin revealed that pretreatment of cells with DNLA significantly alleviated the decrease in protein levels of both PINK1 and Parkin caused by Mn.Furthermore,cells treated with Mn exhibited increased expression of LC3-Ⅱ and a decrease in accumulation of P62,which was noticeably reversed by the pretreatment of cells with DNLA.CONCLUSION DNLA inhibits Mn induced cytotoxicity,which may be mediated through modulating PINK1/Parkin-mediated autophagic flux and improving mitochondrial function.
