Mechanism of Cinnamaldehyde in Promoting Wound Healing in Diabetes Rats via PINK1/Parkin-mediated Mitochondrial Autophagy / 中国实验方剂学杂志

ObjectiveTo establish a rat model of diabetic wound by feeding on a high-fat and high-sugar diet combined with intraperitoneal injection of streptozotocin （STZ） and surgical preparation of full-thickness skin defects， observe the effect of cinnamaldehyde on the wound healing of diabetes rats， and explore the therapeutic mechanism of cinnamaldehyde in improving wound healing of diabetes rats based on the PTEN-induced putative kinase （PINK1）/Parkin pathway-mediated mitochondrial autophagy. MethodForty-eight male SD rats were randomly divided into blank group （n=12） and diabetes group （n=36）. The diabetes group was further randomly divided into model group， cinnamaldehyde group， and Beifuxin group， with 12 rats in each group. The blank group and the model group received routine disinfection with physiological saline after creating the wounds， while the cinnamaldehyde group received topical application of polyethylene glycol 400 （PEG 400） gel containing 4 μmol·L-1 cinnamaldehyde， and the Beifuxin group received topical application of Beifuxin gel. Dressings were changed once daily. The wound healing rate of each group was observed. On the 7th and 14th days after intervention， the wound tissues of the rats were collected. Hematoxylin and eosin （HE） staining was performed to observe the pathological changes in the local tissues. Immunohistochemistry （IHC） was used to detect the expression of interleukin-6 （IL-6）， tumor necrosis factor-α （TNF-α）， vascular endothelial growth factor （VEGF）， and collagen fibers. Immunofluorescence （IF） and Real-time polymerase chain reaction （Real-time PCR） were used to detect the protein， and mRNA expression of PINK1， Parkin， microtubule-associated protein 1 light chain 3 Ⅱ （LC3 Ⅱ）. ResultAfter intraperitoneal injection of STZ， compared with the blank group， the random blood glucose values of rats in the diabetic group increased significantly （P<0.01）， all higher than 16.7 mmol·L-1， and persistently hyperglycemic for some time after modeling. Compared with the blank group， the model group showed poor growth and healing of granulation tissue in the wounds， and the wound healing rate decreased （P<0.01）. On the 7th day after intervention， the blank group had squamous epithelial coverage on the wounds. Compared with the blank group， the model group only had a small amount of scab at the wound edges， with a large number of infiltrating inflammatory cells in the wounds. The protein expression levels of IL-6 and TNF-α in the tissues increased （P<0.01）， and the protein and mRNA levels of PINK1， Parkin， and LC3Ⅱ decreased （P<0.01）. On the 14th day after the intervention， the granulation tissue in the wounds of the blank group was mature and well-healed. Compared with the blank group， the model group still had infiltrating inflammatory cells and red blood cell exudation. The protein expression levels of VEGF and collagen fibers in the tissues decreased （P<0.01）， and the protein and mRNA expression levels of PINK1， Parkin， and LC3Ⅱ increased （P<0.01）. Compared with the model group， the cinnamaldehyde group and the Beifuxin group showed better wound healing， with increased wound healing rates （P<0.01）. On the 7th day after intervention， the protein expression levels of IL-6 and TNF-α in the tissues decreased （P<0.01）， and the protein and mRNA expression levels of PINK1， Parkin， and LC3Ⅱ increased （P<0.01）. On the 14th day after intervention， the protein expression levels of VEGF and collagen fibers in the tissues increased （P<0.01）， and the protein and mRNA expression levels of PINK1， Parkin， and LC3Ⅱ decreased （P<0.01）. ConclusionCinnamaldehyde can promote the wound healing of diabetes rats by increasing the wound healing rate， reducing the levels of inflammatory factors IL-6 and TNF-α， and increasing the levels of VEGF and collagen fibers. Its mechanism may be related to the regulation of the PINK1/Parkin signaling pathway， activation of mitochondrial autophagy， inhibition of inflammatory responses， and promotion of angiogenesis and collagen synthesis， thereby promoting the wound healing of diabetes rats.

Aurantii Fructus Immaturus， Atractylodis Macrocephalae Rhizoma， and Their Combination Treat Colonic Motility Disorders in Rats with Slow Transit Constipation via PINK1/Parkin Signaling Pathway-mediated Mitophagy / 中国实验方剂学杂志

ObjectiveTo observe the effects of Aurantii Fructus Immaturus， Atractylodis Macrocephalae Rhizoma， and their combination on slow transit constipation via PTEN-induced putative kinase 1 （PINK1）/Parkin pathway-mediated mitophagy. MethodFifty-six male SD rats were randomly assigned into normal group， model group， natural recovery group， Aurantii Fructus Immaturus group， Atractylodis Macrocephalae Rhizoma group， Aurantii Fructus Immaturus combined with Atractylodis Macrocephalae Rhizoma group， and mosapride group， with 8 rats in each group. Slow transit constipation model was established by gavage with loperamide （3 mg·kg-1·d-1） for 14 days in other groups except the normal group. After successful modeling， except that the model group was continuously induced by loperamide， the normal group and the natural recovery group were administrated with 0.9% normal saline by gavage， and the rats in the Aurantii Fructus Immaturus （1.35 g·kg-1·d-1） group， the Atractylodis Macrocephalae Rhizoma （2.7 g·kg-1·d-1） group， the Aurantii Fructus Immaturus combined with Atractylodis Macrocephalae Rhizoma （4.05 g·kg-1·d-1） group， and the mosapride （1.56 mg·kg-1·d-1） group were administrated with corresponding drugs by gavage for 7 days. The amount of feces， fecal water content， and intestinal propulsion rate of rats were determined. The pathological changes of the colon were evaluated by hematoxylin-eosin （HE） staining and Alcian blue-periodic acid-Schiff （AB-PAS） staining. The activity of respiratory chain complex and the ultrastructure of the colon tissue were determined by ultraviolet spectrophotometry and observed by transmission electron microscopy， respectively. Real-time fluorescence quantitative polymerase chain reaction（Real-time PCR） was employed to determine the mRNA levels of PINK1， Parkin， and p62， and Western blot to determine the protein levels of microtubule-associated protein 1 light chain 3 （LC3）， PINK1， and Parkin. ResultCompared with the normal group， the model group and the natural recovery group showed decreases in the amount of feces， fecal water content， intestinal propulsion rate （P<0.05，P<0.01）， and activities of mitochondrial respiratory chain complexes Ⅱ， Ⅲ， and Ⅳ in the colon tissue （P<0.05，P<0.01）. Further， the mRNA levels of PINK1 and Parkin and the protein levels of PINK1， Parkin， and LC3 were up-regulated （P<0.01） and the mRNA level of p62 was down-regulated in the model group （P<0.05） and the natural recovery group. Compared with the model group and the natural recovery group， the Aurantii Fructus Immaturus combined with Atractylodis Macrocephalae Rhizoma group showed increased amount of feces， fecal water content， intestinal propulsion rate， and activities of mitochondrial respiratory chain complexes Ⅱ， Ⅲ， and Ⅳ （P<0.05，P<0.01）. Moreover， the combination meliorated the degree of mitochondrial swelling in the colon tissue， down-regulated the mRNA levels of PINK1 and Parkin and the protein levels of PINK1， Parkin， and LC3 （P<0.05，P<0.01）， and up-regulated the mRNA level of p62 （P<0.05）. ConclusionAurantii Fructus Immaturus and Atractylodis Macrocephalae Rhizoma， and their combination may remedy the colonic motility disorders in rats with slow transit constipation by blocking PINK1/Parkin signaling pathway to inhibit the excessive mitophagy in interstitial cells of Cajal in the colon tissue.

Role of Mitophagy in Myocardial Ischemia/Reperfusion Injury and Chinese Medicine Treatment / 中国结合医学杂志

Mitophagy is one of the important targets for the prevention and treatment of myocardial ischemia/reperfusion injury (MIRI). Moderate mitophagy can remove damaged mitochondria, inhibit excessive reactive oxygen species accumulation, and protect mitochondria from damage. However, excessive enhancement of mitophagy greatly reduces adenosine triphosphate production and energy supply for cell survival, and aggravates cell death. How dysfunctional mitochondria are selectively recognized and engulfed is related to the interaction of adaptors on the mitochondrial membrane, which mainly include phosphatase and tensin homolog deleted on chromosome ten (PTEN)-induced kinase 1/Parkin, hypoxia-inducible factor-1 α/Bcl-2 and adenovirus e1b19k Da interacting protein 3, FUN-14 domain containing protein 1 receptor-mediated mitophagy pathway and so on. In this review, the authors briefly summarize the main pathways currently studied on mitophagy and the relationship between mitophagy and MIRI, and incorporate and analyze research data on prevention and treatment of MIRI with Chinese medicine, thereby provide relevant theoretical basis and treatment ideas for clinical prevention of MIRI.

Effect on Danggui Shaoyao Powder on mitophagy in rat model of Alzheimer's disease based on PINK1-Parkin pathway / 中国中药杂志

This study investigated the mechanism of Danggui Shaoyao Powder(DSP) against mitophagy in rat model of Alzheimer's disease(AD) induced by streptozotocin(STZ) based on PTEN induced putative kinase 1(PINK1)-Parkin signaling pathway. The AD rat model was established by injecting STZ into the lateral ventricle, and the rats were divided into normal group, model group, DSP low-dose group(12 g·kg~(-1)·d~(-1)), DSP medium-dose group(24 g·kg~(-1)·d~(-1)), and DSP high-dose group(36 g·kg~(-1)·d~(-1)). Morris water maze test was used to detect the learning and memory function of the rats, and transmission electron microscopy and immunofluorescence were employed to detect mitophagy. The protein expression levels of PINK1, Parkin, LC3BⅠ/LC3BⅡ, and p62 were assayed by Western blot. Compared with the normal group, the model group showed a significant decrease in the learning and memory function(P<0.01), reduced protein expression of PINK1 and Parkin(P<0.05), increased protein expression of LC3BⅠ/LC3BⅡ and p62(P<0.05), and decreased occurrence of mitophagy(P<0.01). Compared with the model group, the DSP medium-and high-dose groups notably improved the learning and memory ability of AD rats, which mainly manifested as shortened escape latency, leng-thened time in target quadrants and elevated number of crossing the platform(P<0.05 or P<0.01), remarkably activated mitophagy(P<0.05), up-regulated the protein expression of PINK1 and Parkin, and down-regulated the protein expression of LC3BⅠ/LC3BⅡ and p62(P<0.05 or P<0.01). These results demonstrated that DSP might promote mitophagy mediated by PINK1-Parkin pathway to remove damaged mitochondria and improve mitochondrial function, thereby exerting a neuroprotective effect.

Effect of ligustrazine on hypoxic-ischemic encephalopathy in neonatal rats by regulating autophagy through the PINK1/Parkin pathway / 中国当代儿科杂志

OBJECTIVES@#To study the effect of ligustrazine injection on mitophagy in neonatal rats with hypoxic-ischemic encephalopathy (HIE) and its molecular mechanism.@*METHODS@#Neonatal Sprague-Dawley rats, aged 7 days, were randomly divided into a sham-operation group with 8 rats, a model group with 12 rats, and a ligustrazine group with 12 rats. The rats in the model group and the ligustrazine group were used to establish a neonatal rat model of HIE by ligation of the left common carotid artery followed by hypoxia treatment, and blood vessels were exposed without any other treatment for the rats in the sham-operation group. The rats in the ligustrazine group were intraperitoneally injected with ligustrazine (20 mg/kg) daily after hypoxia-ischemia, and those in the sham-operation group and the model group were intraperitoneally injected with an equal volume of normal saline daily. Samples were collected after 7 days of treatment. Hematoxylin and eosin staining and Nissl staining were used to observe the pathological changes of neurons in brain tissue; immunohistochemical staining was used to observe the positive expression of PINK1 and Parkin in the hippocampus and cortex; TUNEL staining was used to measure neuronal apoptosis; Western blotting was used to measure the expression levels of the mitophagy pathway proteins PINK1 and Parkin and the autophagy-related proteins Beclin-1, microtubule-associated protein 1 light chain 3 (LC3), and ubiquitin-binding protein (P62).@*RESULTS@#Compared with the sham-operation group, the model group had a significant reduction in the number of neurons, an increase in intercellular space, loose arrangement, lipid vacuolization, and a reduction in Nissl bodies. The increased positive expression of PINK1 and Parkin, apoptosis rate of neurons, and protein expression levels of PINK1, Parkin, Beclin1 and LC3 (P<0.05) and the decreased protein expression level of P62 in the hippocampus were also observed in the model group (P<0.05). Compared with the model group, the ligustrazine group had a significant increase in the number of neurons with ordered arrangement and an increase in Nissl bodies, significant reductions in the positive expression of PINK1 and Parkin, the apoptosis rate of neurons, and the protein expression levels of PINK1, Parkin, Beclin1, and LC3 (P<0.05), and a significant increase in the protein expression level of P62 (P<0.05).@*CONCLUSIONS@#Ligustrazine can alleviate hypoxic-ischemic brain damage and inhibit neuronal apoptosis in neonatal rats to a certain extent, possibly by inhibiting PINK1/Parkin-mediated autophagy.

Effect of Gandou Decoction on Mitophagy in Toxic Milk （TX） Mouse Model of Wilson Disease Based on Pink1/Parkin Pathway / 中国实验方剂学杂志

ObjectiveTo investigate the effects of Gandou decoction （GDD） on the mitophagy of hippocampal neurons in toxic milk （TX） mouse model of Wilson disease and explore the protective mechanism of GDD against neuron injury through the PTEN induced kinase 1 （Pink1） /E3 ubiquitin ligase （Parkin） pathway. MethodSixty mice were randomly divided into a blank group， a model group， a penicillamine group （0.09 g·kg-1）， and low- （5.5 g·kg-1）， medium- （11 g·kg-1）， and high-dose （22 g·kg-1） GDD groups， and treated correspondingly by gavage for 8 weeks. Morris water maze， traction test， and pole test were used for the evaluation of animal behaviors. Hematoxylin-eosin （HE） staining and transmission electron microscopy were used to observe cell apoptosis， ultrastructure， autophagy， and mitochondrial structure. The levels of superoxide dismutase （SOD）， reactive oxygen species （ROS）， and malondialdehyde （MDA） were detected by enzyme-linked immunosorbent assay （ELISA）. Real-time fluorescence-based quantitative polymerase chain reaction （Real-time PCR） was used to detect the mRNA expression of Pink1， Parkin， autophagy-associated protein Beclin-1， microtubule-associated protein 1 light chain 3Ⅱ （LC3Ⅱ）， and p62. Western blot was conducted to detect the protein expression of Pink1， Parkin， Beclin-1， LC3Ⅱ/Ⅰ， and p62. ResultCompared with the blank group， the model group showed prolonged escape latency， decreased times of platform crossing， lower score in the traction test， and longer pole climbing time （P<0.01）. Compared with the model group， the medium- and high-dose GDD groups and the penicillamine group showed shortened escape latencies， increased times of platform crossing， higher scores in the traction test， and shortened pole climbing time （P<0.01）. Compared with the blank group， the model group displayed severely damaged neurons and increased autophagosomes. Compared with the model group， the medium- and high-dose GDD groups and the penicillamine group showed improved neuron damage and reduced autophagosomes. The levels of ROS and MDA were higher and SOD was lower in the model group than those in the blank group （P<0.01）， while the levels of the above indicators were reversed by GDD intervention as compared with the model group （P<0.01）. Compared with the blank group， the model group exhibited up-regulated mRNA and protein expression of Pink1， Parkin， LC3Ⅱ， and Beclin-1 and down-regulated p62 （P<0.05）. Compared with the model group， the medium- and high-dose GDD groups showed reduced mRNA and protein expression of Pink1， Parkin， LC3Ⅱ， and Beclin-1 and increased p62 （P<0.05， P<0.01）. ConclusionGDD can significantly inhibit the excessive mitophagy in neurons of TX mice and protect neurons from damage. The mechanism may be related to the regulation of the Pink1/Parkin pathway.

Mechanism of exogenous hydrogen sulfide-induced reduction of apoptosis in neurons during focal cerebral ischemia-reperfusion in rats: PINK1/Parkin pathway-mediated mitochondrial autophagy / 中华麻醉学杂志

Objective:To investigate the relationship between the mechanism of exogenous hydrogen sulfide (H 2S)-induced reduction of apoptosis in neurons during focal cerebral ischemia-reperfusion (I/R) and PINK1/Parkin pathway-mediated mitochondrial autophagy in rats. Methods:Two hundred and sixteen healthy male Sprague-Dawley rats, aged 6-8 weeks, weighing 250-270 g, were divided into 4 groups ( n=54 each) using a random number table method: control group (group C), I/R group, H 2S group and H 2S plus 3-methyladenine (3-MA) group (H 2S+ 3-MA group). Focal cerebral ischemia was induced by middle cerebral artery occlusion in anesthetized rats.In group H 2S+ 3-MA, 3-MA 10 mg/kg was intraperitoneally injected at 15 min before the onset of reperfusion, while the equal volume of normal saline was given instead in the other groups.In H 2S and H 2S+ 3-MA groups, 0.25% NaSH (a donor of exogenous H 2S) 10 mg/kg was intraperitoneally injected at the onset of reperfusion, while the equal volume of normal saline was given instead in the other groups.At 1, 3 and 7 days of reperfusion, neural function was scored, and corner test (the percentage of left turn was calculated) was performed.Brains were removed and brain tissues were obtained for determination of the cerebral infarct size, Bax, Bcl-2 and caspase-3 positive cells, cell apoptosis, and expression of mitophagy-related protein microtubule-associated protein 1 light chain 3 (LC3), PINK1 and Parkin (by Western blot). The percentage of cerebral infarct size, rate of Bax, Bcl-2 and caspase-3 positive cells and apoptosis rate were calculated.The ratio of LC3-Ⅱexpression to LC3-Ⅰexpression (LC3-Ⅱ/LC3-Ⅰ) was also calculated. Results:Compared with group C, the neural function score was significantly decreased, the percentage of left turn, percentage of cerebral infarct size, rate of Bax, Bcl-2 and caspase-3 positive cells, apoptosis rate of neurons, and LC3-Ⅱ/LC3-Ⅰ were increased, and the expression of PINK1 and Parkin was up-regulated at each time point of reperfusion in group I/R ( P<0.05). Compared with group I/R, the neural function score and rate of Bcl-2 positive cells were significantly increased, the percentage of left turn, percentage of cerebral infarct size, rate of Bax and caspase-3 positive cells, and apoptosis rate of neurons were decreased, the expression of PINK1 and Parkin was up-regulated, and LC3-Ⅱ/LC3-Ⅰ were increased at each time point of reperfusion in group H 2S ( P<0.05), and no significant change was found in the parameters mentioned above in group H 2S+ 3-MA ( P>0.05). Compared with group H 2S, the neural function score and rate of Bcl-2 positive cells were significantly decreased, the percentage of left turn, percentage of cerebral infarct size, rate of Bax and caspase-3 positive cells, and apoptosis rate of neurons were increased, the expression of PINK1 and Parkin was down-regulated, and LC3-Ⅱ/LC3-Ⅰ was decreased at each time point of reperfusion in H 2S+ 3-MA group ( P<0.05). Conclusion:The mechanism by which exogenous H 2S inhibits apoptosis in neurons during focal cerebral I/R is related to enhancing mitochondrial autophagy mediated by the PINK1/Parkin pathway in rats.

Study on the Effects of Tenuifolin on Brain Mitochondrial Autophagy in AD Model Mice Based on PINK 1/Parkin Signaling Pathway / 中国药房

OBJECTIVE：To investig ate the effects of tenuifolin （TEN）on brain mitochondrial autophagy in Aizheimer ’s disease（AD）model mice. METHODS ：Totally 50 male APP/PS1 double transgenic mice were randomly divided into model group，TEN medium-dose+ 3-MA group [TEN 40 mg/（kg·d）+autophagy inhibitor 3-MA 30 mg/（kg·d）] and TEN low-dose ， medium-dose and high-dose groups [ 20，40，80 mg/（kg·d）]，with 10 mice in each group. In addition ，10 wild-type homologous mice were included in normal control group. Administration groups were intragastrically given corresponding drug solution ；normal control group and model group were intragastrically given 0.3％ sodium carboxymethyl cellulose solution ，once a day ，0.01 mL/g， for consecutive 3 months. After last administration ，positive expression [measured by integrated optical density （IOD）] of microtubule associated protein 1 light chain 3（LC3）in neuron was detected ；mRNA expressions of LC3，ubiquitin-binding protein p62，Cathepsin D ，Rab7，phosphatase and tensin homolog deleted on chromosome ten gene-induced putative kinase 1（PINK1） and E 3 ligase（Parkin）as well as protein expressions of LC 3，p62，PINK1 and Parkin were detected in brain mitochondria. RESULTS：Compared with normal control group ，IOD value of LC 3 in neuron as well as mRNA and protein expressions of LC 3， p62，PINK1 and Parkin in brain mitochondria were all increased significantly in model group （P＜0.05 or P＜0.01），while mRNA expressions of Cathepsin D and Rab 7 were decreased significantly （P＜0.05 or P＜0.01）. Compared wit h model group ，IOD values of LC 3（except for TEN low-dose and medium-dose groups ） in neuron ，mRNA expressions of LC 3，Cathepsin D ，Rab7， PINK1（except for TEN low-dose group ）and Parkin （except for TEN low-dose group ） in brain mitochondria as well as protein expressions of LC 3 （except for TEN medium-dose group），PINK1（except fo r TEN high-dose group decreased significantly）and Parkin （except for TEN low-dose group decreased significantly ）were increased significantly in TEN low-dose ， medium-dose and high-dose groups （P＜0.05 or P＜0.01）；mRNA（except for TEN low-dose group ）and protein expressions of p62 were decreased significantly （P＜0.05 or P＜0.01）. Compared with TEN medium-dose group ，the changes of above indexes were inhibited significantly in TEN medium-dose + 3-MA group （P＜0.05 or P＜0.01）. CONCLUSIONS ：TEN can induce mitophagy in brain tissue of AD model mice by activating PINK 1/Parkin signaling pathway and improve lysosome function.

Expression and Significance of Mitochondrial Autophagy-associated Protein PINK1 and Parkin in Parotid Pleomorphic Adenoma and Carcinoma ex Pleomorphic Adenoma / 肿瘤防治研究

Objective To investigate the expression of mitochondrial autophagy-associated protein PINK1 and Parkin in parotid pleomorphic adenoma (PA) and carcinoma ex pleomorphic adenoma(CA-EX-PA). Methods The expression of PINK1 and Parkin were detected by immunohistochemistry in 24 cases of normal parotid gland tissues, 32 cases of PA tissues and 42 cases of CA-EX-PA tissues. The correlations of PINK1 and Parkin expression with the clinicopathologic characteristics of CA-EX-PA patients were analyzed. Results The positive rates of PINK1 in normal parotid gland, PA and CA-EX-PA tissues were 100%, 91% and 67% respectively; and those of Parkin were 100%, 88% and 52% respectively. The expression rates of PINK1 and Parkin in PA and CA-EX-PA tissues were significantly lower than those in normal tissues (P < 0.05). The expression of PINK1 and Parkin protein were positively correlated in CA-EX-PA tissues (r=0.877, P < 0.01). In CA-EX-PA tissues, the expression of PINK1 and Parkin were associated with tumor invasion, lymph node metastasis and TNM stage (P < 0.05). Conclusion The expression of PINK1 and Parkin are decreased in PA and CA-EX-PA tissues. The decrease of mitochondrial autophagy activity might play important roles in the development, invasion and metastasis of parotid gland tumors.

Tongxinluo Ameliorates Myocardial Ischemia-Reperfusion Injury Mainly via Activating Parkin-Mediated Mitophagy and Downregulating Ubiquitin-Proteasome System / 中国结合医学杂志

OBJECTIVE@#To investigate the protective effects and mechanism of Chinese herbal compound Tongxinluo Capsule (, TXL) on the Parkin-mediated mitophagy and the ubiquitin-proteasome system in a rat model of myocardial ischemia-reperfusion injury (MIRI).@*METHODS@#Seventy adult male Sprague-Dawley rats were randomly divided into 7 groups: sham group, MIRI group, low- and high-dose TXL (0.5 and 1 g·kg@*RESULTS@#Compared with the sham group, the MIRI group exhibited a larger infarcted area (27.13%±0.01%, P<0.01), a higher apoptotic index (34.33%±2.03% vs.1.81%±0.03%, P<0.01), and higher cTnI expression (14.18±1.01 vs. 7.96±0.32, P<0.01). The mitochondrial integrity was damaged in the MIRI group, while TXL and ATV alleviated the damage of MIRI. More autophagosomes were observed in the high-dose TXL group than in the MIRI group (7.00±0.58 vs. 4.33±1.15, P<0.05). More amounts of PTEN-induced putative kinase protein 1 (PINK1) and Parkin translocated onto the mitochondria were detected in the high-dose TXL group than in the MIRI group (P<0.05). The ubiquitin response was signifificantly downregulated in the high-dose TXL group relative to the MIRI group (P<0.05). CQ administration abolished the activation of autophagy flux and the PINK1/ Parkin pathway induced by high-dose of TXL.@*CONCLUSIONS@#TXL ameliorates MIRI via activating Parkin-mediated mitophagy in rats. The downregulation of the ubiquitin-proteasome system is also involved.

Ablation of Akt2 and AMPKα2 rescues high fat diet-induced obesity and hepatic steatosis through Parkin-mediated mitophagy

@#Given the opposing effects of Akt and AMP-activated protein kinase (AMPK) on metabolic homeostasis, this study examined the effects of deletion of Akt2 and AMPKα2 on fat diet-induced hepatic steatosis. Akt2–Ampkα2 double knockout (DKO) mice were placed on high fat diet for 5 months. Glucose metabolism, energy homeostasis, cardiac function, lipid accumulation, and hepatic steatosis were examined. DKO mice were lean without anthropometric defects. High fat intake led to adiposity and decreased respiratory exchange ratio (RER) in wild-type (WT) mice, which were ablated in DKO but not Akt2−/− and Ampkα2−/− mice. High fat intake increased blood and hepatic triglycerides and cholesterol, promoted hepatic steatosis and injury in WT mice. These effects were eliminated in DKO but not Akt2−/− and Ampkα2−/− mice. Fat diet promoted fat accumulation, and enlarged adipocyte size, the effect was negated in DKO mice. Fat intake elevated fatty acid synthase (FAS), carbohydrate-responsive element-binding protein (CHREBP), sterol regulatory element-binding protein 1 (SREBP1), peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α), peroxisome proliferator-activated receptor-α (PPARα), PPARγ, stearoyl-CoA desaturase 1 (SCD-1), phosphoenolpyruvate carboxykinase (PEPCK), glucose 6-phosphatase (G6Pase), and diglyceride O-acyltransferase 1 (DGAT1), the effect was absent in DKO but not Akt2−/− and Ampkα2−/− mice. Fat diet dampened mitophagy, promoted inflammation and phosphorylation of forkhead box protein O1 (FoxO1) and AMPKα1 (Ser485), the effects were eradicated by DKO. Deletion of Parkin effectively nullified DKO-induced metabolic benefits against high fat intake. Liver samples from obese humans displayed lowered microtubule-associated proteins 1A/1B light chain 3B (LC3B), Pink1, Parkin, as well as enhanced phosphorylation of Akt, AMPK (Ser485), and FoxO1, which were consolidated by RNA sequencing (RNAseq) and mass spectrometry analyses from rodent and human livers. These data suggest that concurrent deletion of Akt2 and AMPKα2 offers resilience to fat diet-induced obesity and hepatic steatosis, possibly through preservation of Parkin-mediated mitophagy and lipid metabolism.

Synergistic effects of autophagy/mitophagy inhibitors and magnolol promote apoptosis and antitumor efficacy

Mitochondria as a signaling platform play crucial roles in deciding cell fate. Many classic anticancer agents are known to trigger cell death through induction of mitochondrial damage. Mitophagy, one selective autophagy, is the key mitochondrial quality control that effectively removes damaged mitochondria. However, the precise roles of mitophagy in tumorigenesis and anticancer agent treatment remain largely unclear. Here, we examined the functional implication of mitophagy in the anticancer properties of magnolol, a natural product isolated from herbal

Apigenin attenuates myocardial infarction-induced cardiomyocyte injury by modulating Parkin-mediated mitochondrial autophagy

We aimed to detect whether the effect of apigenin (Apig) on the myocardial infarction-induced cardiomyocyte injury ofmouse myocardial cells and acute myocardial infarction (AMI) mice was through regulating Parkin expression viamiR-103-1-5p. The myocardial infarction cardiomyocyte model (Hypoxia/reoxygenation) was first constructed, thenthe mouse myocardial cells were treated with Apig, and the expression of miR-103-1-5p was decreased and theexpression of Parkin was increased by qRT-PCR and Western blot. It was confirmed by miRNA pulldown andluciferase reporter system that miR-103-1-5p in mouse myocardial cells can bind to Parkin mRNA and inhibit Parkinexpression. Next, a lentiviral vector silenced Parkin and overexpressing miR-103-1-5p was constructed and transfectedinto Apig-treated cells. Autophagy was detected by mitochondrial autophagy marker proteins [atypical protein kinaseC (aPKC)-interacting protein (p62) and bcl-2/Adenovirus E1B 19-kd interacting protein 3 (BNIP3)] via Western blot,mitochondrial function was detected by JC-1 probe, and apoptosis was detected by flow cytometry. It was confirmedthat Apig regulated mitochondria autophagy through miR-103-1-5p and Parkin, which ultimately affected cardiomyocyte death. Finally, an AMI mouse model was constructed, and then the mice were treated with Apig. Theinfarct size was detected by triphenyl tetrazolium chloride (TTC) staining, and the Apig relieved the myocardialinfarction. The expression of miR-103-1-5p was decreased and the expression of Parkin was increased by qRT-PCRand Western blot. The above results simplified that the cardio protection of Apig and miR-103-1-5p against injury ofmyocardial infarction cardiomyocyte by targeting Parkin. These results provided a novel treatment against myocardialinfarction cardiomyocyte.

Role of pinkl/parkin-mediated mitochondrial autophagy in a rat model of brain injury / 中国组织工程研究

BACKGROUND: In addition to FUNDC1, Bnip3 and Nix mitochondrial autophagy pathways in mammals that are closely related to the hypoxic environment, Pinkl/Parkin is the main mitochondrial autophagy pathway after brain injury. PINK1 acts upstream of Parkin, and the Pinkl/Parkin pathway is used to mediate loss of mitochondrial surface functional proteins or structural polyubiquitination, and considered as a marker for autophagosome selection, which has an important influence on autophagy-dependent degradation of depolarized mitochondria. OBJECTIVE: To analyze the role of Pinkl/Parkin-mediated mitochondrial autophagy in rats with brain injury after hypertensive intracerebral hemorrhage. METHODS: The study was approved by the Laboratory Animal Ethical Committee of North Sichuan Medical College. Forty-five male Wistar rats of SPF grade were randomly divided into normal, model and autophagy inhibitor groups. The rats in the model and autophagy inhibitor groups were used to prepare hypertensive cerebral hemorrhage model. Before modeling 2 µL of PBS solution containing trimethyl adenine (100 nmol/L) was intraperitoneally injected in the inhibitor group, and the model and the normal groups were intraperitoneally injected with 2 µL of PBS. The water content, mitochondrial autophagy, mitochondrial membrane potential, cerebral infarction, mitochondrial LC3, Parkin protein and PINK1 protein expression in brain tissue were detected. RESULTS AND CONCLUSION: (1) Compared with the normal group, the autophagy staining and mitochondrial staining expression in the model group was increased, and the number of co-localized positive cells was increased (both P < 0.05). Compared with the model group, the autophagy staining and mitochondrial staining expression in the autophagy inhibitor group was decreased, and the number of co-localized positive cells was decreased (both P < 0.05). (2) Compared with the normal group, the infarction proportion of the brain in the model group was increased (P < 0.05). Compared with the model group, the infarction proportion of the brain in the autophagy inhibitor group was increased (P < 0.05). (3) Compared with the normal group, the mitochondrial staining intensity in the model group was decreased, and the autophagy staining intensity was increased (both P < 0.05). Compared with the model group, the mitochondrial staining intensity in the autophagy inhibitor group was decreased, and the autophagy staining intensity was increased (both P < 0.05). (4) Compared with the normal group, the expression levels of PINK1, LC3 and Parkin in the model group were increased (P < 0.05). Compared with the model group, the expression levels of PINK1, LC3 and Parkin in the autophagy inhibitor group were decreased (P < 0.05). In summary, mitochondrial autophagy can alleviate the degree of brain injury after hypertensive intracerebral hemorrhage. The Pinkl/Parkin pathway plays an important role in the mitochondrial autophagy.

Rosmarinic acid inhibits high glucose-induced cardiomyocyte hypertrophy by activating Parkin-mediated mitophagy / 南方医科大学学报

OBJECTIVE@#To evaluate the effect of rosmarinic acid (RA) on mitophagy and hypertrophy of cardiomyocytes exposed to high glucose (HG).@*METHODS@#Rat cardiomyocytes (H9c2) exposed to HG (25 mmol/L) were treated with 50 μmol/L RA or with both RA treatment and Parkin siRNA transfection, with the cells cultured in normal glucose (5.5 mmol/L) and HG as the controls. The expressions of PINK1, Parkin and LC3II/LC3I in the cells were detected by Western blotting. The formation of mitochondrial autophagosomes was observed by transmission electron microscope. Flow cytometry was employed to detect the level of reactive oxygen species (ROS) and apoptotic rate of the cells. The activities of respiratory chain complex enzymes were measured by spectrophotometry. Fluorescence enzyme labeling and @*RESULTS@#RA treatment significantly increased the expression levels of PINK1, Parkin and LC3-II/I (@*CONCLUSIONS@#RA can protect rat cardiomyocytes against oxidative stress injury and cardiomyocyte hypertrophy induced by HG by activating Parkin-mediated mitophagy.

PINK1/Parkin-mediated mitophagy and its mechanism of action in the development and progression of liver diseases / 临床肝胆病杂志

Mitophagy is the process of selective clearance of damaged mitochondria by autophagy. There are several regulatory mechanisms for mitophagy, and the PINK1/Parkin pathway is considered the main pathway for mitophagy. Recent studies have shown that PINK1/Parkin-mediated mitophagy plays an important role in the pathogenesis of various diseases including Parkinson’s disease. This article introduces the mechanism of PINK1/Parkin-mediated mitophagy and its role in various liver diseases including nonalcoholic fatty liver disease, liver fibrosis, and hepatocellular carcinoma, in order to provide new clues and ideas for the treatment of diseases.

Involvement of phosphatase and tensin homolog-induced putative kinase 1–Parkin-mediated mitophagy in septic acute kidney injury / 中华医学杂志(英文版)

Background@#Studies have reported mitophagy activation in renal tubular epithelial cells (RTECs) in acute kidney injury (AKI). Phosphatase and tensin homolog-induced putative kinase 1 (PINK1) and E3 ubiquitin-protein ligase Parkin are involved in mitophagy regulation; however, little is known about the role of PINK1-Parkin mitophagy in septic AKI. Here we investigated whether the PINK1-Parkin mitophagy pathway is involved in septic AKI and its effects on cell apoptosis in vitro and on renal functions in vivo.@*Methods@#Mitophagy-related gene expression was determined using Western blot assay in human RTEC cell line HK-2 stimulated with bacterial lipopolysaccharide (LPS) and in RTECs from septic AKI rats induced by cecal ligation and perforation (CLP). Autophagy-related ultrastructural features in rat RTECs were observed using electron microscopy. Gain- and loss-of-function approaches were performed to investigate the role of the PINK1-Parkin pathway in HK-2 cell mitophagy. Autophagy activators and inhibitors were used to assess the effects of mitophagy modulation on cell apoptosis in vitro and on renal functions in vivo.@*Results@#LPS stimulation could significantly induce LC3-II and BECN-1 protein expression (LC3-II: 1.72 ± 0.05 vs. 1.00 ± 0.05, P < 0.05; BECN-1: 5.33 ± 0.57 vs. 1.00 ± 0.14, P < 0.05) at 4 h in vitro. Similarly, LC3-II, and BECN-1 protein levels were significantly increased and peaked at 2 h after CLP (LC3-II: 3.33 ± 0.12 vs. 1.03 ± 0.15, P < 0.05; BECN-1: 1.57 ± 0.26 vs. 1.02 ± 0.11, P < 0.05) in vivo compared with those after sham operation. Mitochondrial deformation and mitolysosome-mediated mitochondria clearance were observed in RTECs from septic rats. PINK1 knockdown significantly attenuated LC3-II protein expression (1.35 ± 0.21 vs. 2.38 ± 0.22, P < 0.05), whereas PINK1 overexpression markedly enhanced LC3-II protein expression (2.07 ± 0.21 vs. 1.29 ± 0.19, P < 0.05) compared with LPS-stimulated HK-2 cells. LPS-induced proapoptotic protein expression remained unchanged in autophagy activator-treated HK-2 cells and was significantly attenuated in PINK1-overexpressing cells, but was remarkably upregulated in autophagy inhibitor-treated and in PINK1-depleted cells. Consistent results were observed in flow cytometric apoptosis assay and in renal function indicators in rats.@*Conclusion@#PINK1-Parkin-mediated mitophagy might play a protective role in septic AKI, serving as a potential therapeutic target for septic AKI.

Expression of Parkin protein in colorectal cancer and its clinical significance / 中国医师进修杂志

Objective To investigate the expression of Parkin protein in colorectal cancer and its clinical significance. Methods Immunohistochemistry was used to detect the expression of Parkin protein in normal and cancerous tissues of 50 patients with colorectal cancer from 2012 to 2015. The relationship between clinicopathological characteristics and Parkin protein expression was analyzed. Results The positive expression rate of Parkin protein in cancerous tissues was significantly lower than that in normal tissues: 36% (18/50) vs. 72% (36/50), and there was statistical difference (P＜0.01). The positive expression of Parkin protein was correlated with the degree of tissue differentiation (P < 0.01);but it was not correlated with sex, age, tumor diameter, tumor type, tumor infiltration, lymph node metastasis and clinical stage (P＞0.05). Conclusions In colorectal cancer tissues, the expression of Parkin gene is absent and decreased. The abnormal expression of Parkin gene may be related to the occurrence and development of colorectal cancer.

Effect of acupuncture on mitophagy of skeletal muscle in rats with exer-cise-induced skeletal muscle damage / 中国病理生理杂志

AIM:The effect of acupuncture on mitophagy-related protein expression in skeletal muscle of rats after heavy-load exercise was investigated to explore the role of acupuncture in the repairment of exercise-induced skeletal muscle damage. METHODS:Male adult Sprague-Dawley rats (n=128) were randomly divided into 4 groups:control (C,n=8) group, exercise (E, n=40) group, acupuncture (A, n=40) group, and exercise and acupuncture (EA, n=40) group. The rats in E group and EA group performed an eccentric exercise,and the rats in A group and EA group immediately after exercise received acupuncture treatment. The rats in the latter 3 groups were further divided into 0 h,12 h,24 h,48 h and 72 h sub-groups(n=8),and soleus muscle was collected at each time point. The transmission electron microscopy was used to observe the ultrastructural changes of the mitochondria in skeletal muscle. The content of citrate synthase (CS) was measured by ELISA. The protein expression of skeletal muscle PTEN-induced putative kinase 1 (PINK1),parkin and microtubule-associated protein 1 light chain 3 (LC3) was determined by Western blot. RESULTS:After the heavy-load exercise,the mitochondria swelled and accumulated under cell membrane. The number of mitophago-somes was increased,and the content of CS was significantly decreased(P<0.05). The expression of PINK1,parkin and LC3 was significantly elevated (P<0.05). However,the acupuncture intervention after exercise promoted the recovery of mitochondrial ultrastructure, attenuated mitophagolysosome formation, maintained CS content and down-regulated the ex-pression of PINK1,parkin and LC3 (P<0.05). CONCLUSION:Heavy-load exercise causes the damages of mitochon-drial structure and function in the skeletal muscle and activates PINK1/parkin pathway to induce excessive occurrence of mitophagy. Acupuncture intervention after exercise is able to alleviate the damage of mitochondria in the skeletal muscle through decreasing the expression of mitochondrial outer membrane protein PINK1,reducing the recruitment of downstream cytoplasmic protein parkin,thereby affecting the combination of LC3 and mitochondria to inhibit the overactivation of mito-phagy.

Some diseases caused by Parkin / 中国药理学通报

Since Parkin was confirmed by the Japanese scholar to be associated with juvenile Parkinson′s disease, it has come to be the focus of the scholars and a lot of researches have been made on it. Apart from Parkinson′s disease, many other disea-ses have also been proved to be associated with the role of Parkin and its interaction with protein substrates, especially in various kinds of cancer diseases and leukemia. This paper focuses on the latest research about Parkin and its development in tumor diseases and leukemia.