BACKGROUND:Whether coiled-coil-helix-coiled-coil-helix domain-containing 2(CHCHD2)can regulate the neuroprotective role of PINK1/Parkin-mediated mitochondrial autophagy in Parkinson's disease remains unknown.OBJECTIVE:To explore the role and mechanisms of CHCHD2 in the 6-hydroxydopamine-induced Parkinson's disease cell model in mediating the PINK1/Parkin signaling pathway and its involvement in mitochondrial autophagy.METHODS:Utilizing recombinant plasmid transfection technology to overexpress or knockdown CHCHD2,SH-SY5Y cells were constructed with a Parkinson's disease model using 6-hydroxydopamine,and divided into control group,model group,overexpression negative control+6-hydroxydopamine group,knockdown negative control+6-hydroxydopamine group,overexpression CHCHD2+6-hydroxydopamine group,and knockdown CHCHD2+6-hydroxydopamine group.Western blot assay and RT-qPCR were used to detect CHCHD2 expression.Western blot assay was utilized to detect the protein expression of LC3Ⅰ/Ⅱ,p62,MFN1,COXIV,DRP1,PINK1,Parkin,TIM23,Bax,Bcl-2,and cleaved-caspase 3.CCK-8 assay,JC-1,and reactive oxygen species assay kits were used to measure cell viability,mitochondrial membrane potential,and reactive oxygen levels.Monodansylcadaverine staining was used to observe cell autophagy.Transmission electron microscopy was used to observe autophagolysosomes.RESULTS AND CONCLUSION:(1)Compared with the control group,cell activity,mitochondrial membrane potential,and the protein expression levels of CHCHD2,PINK1,and Parkin were decreased,and the levels of reactive oxygen species,apoptosis,and LC3Ⅰ/Ⅱ and p62 proteins were increased(P＜0.05),and the presence of autophagic lysosomes was observed in the model group.(2)Compared with the model group,overexpression of CHCHD2 could reduce the level of cellular reactive oxygen species,increase the mitochondrial membrane potential,and the expression levels of PINK1,Parkin,and MFN1 proteins,and observed an increase in mitochondrial autolysosomes,and the knockdown of CHCHD2 had the opposite effect with the increase of COXIV,TIM23 and p-DRP1 protein expression(P＜0.05).(3)Compared with the model group,overexpression of CHCHD2 reduced apoptosis,up-regulated Bcl-2,and down-regulated the expression of Bax and cleaved-caspase3 proteins,while knockdown of CHCHD2 had the opposite effect(P＜0.05).(4)The results suggest that CHCHD2 can play a neuroprotective role by promoting PINK1/Parkin-mediated mitochondrial autophagy,improving mitochondrial function,and alleviating apoptosis in 6-hydroxydopamine-induced Parkinson's disease cell models.

BACKGROUND:Whether coiled-coil-helix-coiled-coil-helix domain-containing 2(CHCHD2)can regulate the neuroprotective role of PINK1/Parkin-mediated mitochondrial autophagy in Parkinson's disease remains unknown.OBJECTIVE:To explore the role and mechanisms of CHCHD2 in the 6-hydroxydopamine-induced Parkinson's disease cell model in mediating the PINK1/Parkin signaling pathway and its involvement in mitochondrial autophagy.METHODS:Utilizing recombinant plasmid transfection technology to overexpress or knockdown CHCHD2,SH-SY5Y cells were constructed with a Parkinson's disease model using 6-hydroxydopamine,and divided into control group,model group,overexpression negative control+6-hydroxydopamine group,knockdown negative control+6-hydroxydopamine group,overexpression CHCHD2+6-hydroxydopamine group,and knockdown CHCHD2+6-hydroxydopamine group.Western blot assay and RT-qPCR were used to detect CHCHD2 expression.Western blot assay was utilized to detect the protein expression of LC3Ⅰ/Ⅱ,p62,MFN1,COXIV,DRP1,PINK1,Parkin,TIM23,Bax,Bcl-2,and cleaved-caspase 3.CCK-8 assay,JC-1,and reactive oxygen species assay kits were used to measure cell viability,mitochondrial membrane potential,and reactive oxygen levels.Monodansylcadaverine staining was used to observe cell autophagy.Transmission electron microscopy was used to observe autophagolysosomes.RESULTS AND CONCLUSION:(1)Compared with the control group,cell activity,mitochondrial membrane potential,and the protein expression levels of CHCHD2,PINK1,and Parkin were decreased,and the levels of reactive oxygen species,apoptosis,and LC3Ⅰ/Ⅱ and p62 proteins were increased(P＜0.05),and the presence of autophagic lysosomes was observed in the model group.(2)Compared with the model group,overexpression of CHCHD2 could reduce the level of cellular reactive oxygen species,increase the mitochondrial membrane potential,and the expression levels of PINK1,Parkin,and MFN1 proteins,and observed an increase in mitochondrial autolysosomes,and the knockdown of CHCHD2 had the opposite effect with the increase of COXIV,TIM23 and p-DRP1 protein expression(P＜0.05).(3)Compared with the model group,overexpression of CHCHD2 reduced apoptosis,up-regulated Bcl-2,and down-regulated the expression of Bax and cleaved-caspase3 proteins,while knockdown of CHCHD2 had the opposite effect(P＜0.05).(4)The results suggest that CHCHD2 can play a neuroprotective role by promoting PINK1/Parkin-mediated mitochondrial autophagy,improving mitochondrial function,and alleviating apoptosis in 6-hydroxydopamine-induced Parkinson's disease cell models.

BACKGROUND:Studies have found that nicotine can activate the dopamine system,slowing the progression of Parkinson's disease,but the specific mechanism is still unclear.Research on the neuroprotective mechanism of nicotine in animal models of Parkinson's disease is lacking. OBJECTIVE:To investigate the neuroprotective effect of nicotine on rotenone-induced Parkinson's disease in mice. METHODS:Twenty-eight C57BL/6 mice were randomly divided into vehicle group,rotenone group,autophagy agonist group and nicotine group,with seven mice in each group.Dopaminergic nerve damage was induced by rotenone in C57BL/6 mice,and the autophagy agonist(rapamycin)or nicotine was given before modeling.The spatial exploration function of the mice was observed by open field test.Western blot and Q-PCR were used to detect the expression of α-synuclein,autophagy related factors Beclin-1 and P62,and apoptosis-related factors Bax,Bcl-2 and Cleaved-caspase3 in the nigra of each group.The deposition of mitochondria,autophagosomes and lipofuscin in nigra cells were observed by transmission electron microscopy.The survival of neurons was observed by Nissl staining.The expression of tyrosine hydroxylase was observed by immunofluorescence and immunohistochemical staining. RESULTS AND CONCLUSION:The open field test showed that the distance,average speed and time of movement were reduced in the rotenone group compared with the solvent group.Compared with the rotenone group,the exercise distance,average speed and exercise time of mice were increased in the nicotine group and autophagy agonist group(P＜0.05).The results of immunofluorescence and immunohistochemistry showed that the mean fluorescence intensity and mean absorbance value of tyrosine hydroxylase in the rotenone group decreased compared with that in the solvent group.Compared with the rotenone group,the mean fluorescence intensity and mean absorbance value of tyrosine hydroxylase were increased in the nicotine group and autophagy agonist group.Western blot and Q-PCR results showed that compared with the solvent group,the expressions of α-synuclein and P62 in the rotenone group were increased,while Beclin-1 expression was decreased(P＜0.05);compared with the rotenone group,the expression of α-synuclein and P62 decreased in the nicotine group and autophagy agonist group,and the expression of Beclin-1 increased(P＜0.05).Compared with the solvent group,the expressions of Bax and Cleaved caspase3 were increased and Bcl-2 expression was decreased in the rotenone group(P＜0.05);compared with the rothenone group,the expressions of Bax and Cleaved-caspase3 were decreased and the expression of Bcl-2 was increased in the nicotine and autophagy agonist groups(P＜0.05).To conclude,nicotine may have a dopaminergic neuroprotective effect on rotenone-induced Parkinson's disease mouse models by improving autophagy dysfunction and reducing apoptosis.

Objective To analyze the expression of MIAT in colorectal cancer and explore its molecular mechanism.Methods The expression of MIAT mRNA in colorectal cancer tissues and paracancerous tissues,colorectal cancer cell lines and human normal colorectal mucosa cells was detected by RT-qPCR.HCT-116 cells were transfected with MIAT overexpression vector and infected with knockdown lentivirus,cell proliferation and cell cycle were detected,Western blot was used to analyze the β3-catenin protein levels,luciferase assay was used to detect β-catenin promoter transcription level,C-myc,CCND1,CD44 and Oct3/4 mRNA levels was measured by RT-qPCR.Results The expression of MIAT in colorectal cancer tissues was significantly higher than that in adjacent tissues (t =4.093,P ＜ 0.05).Overexpression of MIAT could promote the proliferation of HCT-116 cells,decrease the rate of G0/G1 phase,activate Wnt/β-catenin pathway and increase its downstream target gene mRNA expression levels (all P ＜ 0.05).Knockdown MIAT shows the inhibition effect.Conclusions MIAT is a tumor-promoting gene of colorectal cancer and may play a role in tumor promotion by activating Wnt/β3-catenin pathway.