Age-related mitophagy regulates orthodontic tooth movement by affecting PDLSCs mitochondrial function and RANKL/OPG.

A thorough comprehension of age-related variances in orthodontic tooth movement (OTM) and bone remodeling response to mechanical force holds significant implications for enhancing orthodontic treatment. Mitophagy plays a crucial role in bone metabolism and various age-related diseases. However, the impact of mitophagy on the bone remodeling process during OTM remains elusive. Using adolescent (6 weeks old) and adult (12 months old) rats, we established OTM models and observed that orthodontic force increased the expression of the mitophagy proteins PTEN-induced putative kinase 1 (PINK1) and Parkin, as well as the number of tartrate-resistant acid phosphatase-positive osteoclasts and osteocalcin-positive osteoblasts. These biological changes were found to be age-related. In vitro, compression force loading promoted PINK1/Parkin-dependent mitophagy in periodontal ligament stem cells (PDLSCs) derived from adolescents (12-16 years old) and adults (25-35 years old). Furthermore, adult PDLSCs exhibited lower levels of mitophagy, impaired mitochondrial function, and a decreased ratio of RANKL/OPG compared to young PDLSCs after compression. Transfection of siRNA confirmed that inhibition of mitophagy in PDLSC resulted in decreased mitochondrial function and reduced RANKL/OPG ratio. Application of mitophagy inducer Urolithin A enhanced bone remodeling and accelerated OTM in rats, while the mitophagy inhibitor Mdivi-1 had the opposite effect. These findings indicate that force-stimulated PDLSC mitophagy contributes to alveolar bone remodeling during OTM, and age-related impairment of mitophagy negatively impacts the PDLSC response to mechanical stimulus. Our findings enhance the understanding of mitochondrial mechanotransduction and offer new targets to tackle current clinical challenges in orthodontic therapy.

FGF4 protects the liver from immune-mediated injury by activating CaMKKß-PINK1 signal pathway to inhibit hepatocellular apoptosis.

Immune-mediated liver injury (ILI) is a condition where an aberrant immune response due to various triggers causes the destruction of hepatocytes. Fibroblast growth factor 4 (FGF4) was recently identified as a hepatoprotective cytokine; however, its role in ILI remains unclear. In patients with autoimmune hepatitis (type of ILI) and mouse models of concanavalin A (ConA)- or S-100-induced ILI, we observed a biphasic pattern in hepatic FGF4 expression, characterized by an initial increase followed by a return to basal levels. Hepatic FGF4 deficiency activated the mitochondria-associated intrinsic apoptotic pathway, aggravating hepatocellular apoptosis. This led to intrahepatic immune hyper-reactivity, inflammation accentuation, and subsequent liver injury in both ILI models. Conversely, administration of recombinant FGF4 reduced hepatocellular apoptosis and rectified immune imbalance, thereby mitigating liver damage. The beneficial effects of FGF4 were mediated by hepatocellular FGF receptor 4, which activated the Ca2+/calmodulin-dependent protein kinasekinase 2 (CaMKKß) and its downstream phosphatase and tensin homologue-induced putative kinase 1 (PINK1)-dependent B-cell lymphoma 2-like protein 1-isoform L (Bcl-XL) signalling axis in the mitochondria. Hence, FGF4 serves as an early response factor and plays a protective role against ILI, suggesting a therapeutic potential of FGF4 and its analogue for treating clinical immune disorder-related liver injuries.

Effects of electroacupuncture on mitophagy mediated by SIRT3/PINK1/Parkin pathway in Parkinson's disease mice. / ç”µé’ˆå¯¹å¸•é‡‘æ£®ç— å°é¼ SIRT3/PINK1/Parkin通路介导的线粒体自噬的影响.

OBJECTIVES: To observe the effects of electroacupuncture (EA) at "Fengfu"(GV16), "Taichong"(LR3), and "Zusanli"(ST36) on mitophagy mediated by silencing regulatory protein 3 (SIRT3)/ PTEN induced putative kinase 1 (PINK1)/PARK2 gene coding protein (Parkin) in the midbrain substantia nigra of Parkinson's disease (PD) mice, and to explore the potential mechanisms of EA in treating PD. METHODS: C57BL/6 mice were randomly divided into the control, model, EA, and sham EA groups, with 12 mice in each group. The PD mouse model was established by intraperitoneal injection of 1-methyl-4-phenyl-1, 2, 3, 6-tetrahydropyridine (MPTP). The EA group received EA stimulation at GV16, LR3 and ST36, while the sham EA group received shallow needling 1 mm away from the above acupoints without electrical stimulation. The motor ability of mice in each group was evaluated using an open field experiment. Immunohistochemistry was used to detect the expression of tyrosine hydroxylase (TH) and α-synuclein (α-syn) in the substantia nigra of mice. The ultrastructure of neurons in substantia nigra was observed by transmission electron microscope (TEM). Immunofluorescence was used to detect the expression of the autophagy marker autophagy-associated protein light chain 3 (LC3). The expression levels of TH, α-syn, SIRT3, PINK1, Parkin, P62, Beclin-1, LC3Ⅱ mRNA and protein were detected by PCR and Western blot. RESULTS: Compared with the control group, mice in the model group showed a decrease in the total exercise distance, time, movement speed and times of crossing central region (P<0.01)；the positive expressions of TH and LC3 were decreased (P<0.01), while the positive expression of α-syn increased (P<0.01), accompanied by mitochondrial swelling, mitochondrial cristae fragmentation and decrease, and decreased lysosome count；the expression levels of TH, SIRT3, PINK1, Parkin, Beclin-1, and LC3Ⅱ mRNA and protein in the midbrain substantia nigra were decreased (P<0.01), while the expression levels of α-syn and P62 mRNA and protein were increased (P<0.01, P<0.05). Compared with the model group, the mice in EA group showed a significant increase in the total exercise distance, time, movement speed and times of crossing central region (P<0.01, P<0.05)；the positive expressions of TH and LC3 were increased (P<0.01, P<0.05), while the positive expression of α-syn was decreased (P<0.01), accompanied by an increase in mitochondrial count, appearance of autophagic va-cuoles, and a decrease in swelling, the expression levels of TH, SIRT3, PINK1, Parkin, Beclin-1 and LC3Ⅱ mRNA and protein in the midbrain substantia nigra were increased (P<0.01, P<0.05), while the mRNA and protein expression levels of α-syn and P62 were decreased (P<0.01)；the sham EA group showed an increase in the total exercise distance and time(P<0.05), with an increase in the positive expression of TH (P<0.05) and a decrease in the positive expression of α-syn (P<0.05)；some mitochondria exhibited swelling, and no autophagic vacuoles were observed；the protein expression levels of TH, SIRT3, Parkin and LC3Ⅱ were increased (P<0.01, P<0.05), and the expression levels of P62 mRNA, α-syn mRNA and protein were decreased (P<0.01, P<0.05), and LC3Ⅱ mRNA expression was increased (P<0.05). In comparison to the sham EA group, the EA group showed an extension in the total exercise time (P<0.01), the positive expression and mRNA expression levels of α-syn were decreased (P<0.01, P<0.05), while the expression levels of TH, SIRT3, PINK1, Parkin mRNA and SIRT3 protein were increased (P<0.05). CONCLUSIONS: EA at GV16, LR3, and ST36 can exert neuroprotective function and improve the motor ability of PD mice by activating the SIRT3/PINK1/Parkin pathway to enhance the expression of TH and reduce α-syn aggregation in the substantia nigra of PD mice.

Low Selenium and Low Protein Exacerbate Myocardial Damage in Keshan Disease by Affecting the PINK1/Parkin-mediated Mitochondrial Autophagy Pathway.

OBJECTIVE: Keshan disease (KD) is a myocardial mitochondrial disease closely related to insufficient selenium (Se) and protein intake. PTEN induced putative kinase 1 (PINK1)/Parkin mediated mitochondrial autophagy regulates various physiological and pathological processes in the body. This study aimed to elucidate the relationship between PINK1/Parkin-regulated mitochondrial autophagy and KD-related myocardial injury. METHODS: A low Se and low protein animal model was established. One hundred Wistar rats were randomly divided into 5 groups (control group, low Se group, low protein group, low Se + low protein group, and corn from KD area group). The JC-1 method was used to detect the mitochondrial membrane potential (MMP). ELISA was used to detect serum creatine kinase MB (CK-MB), cardiac troponin I (cTnI), and mitochondrial-glutamicoxalacetic transaminase (M-GOT) levels. RT-PCR and Western blot analysis were used to detect the expression of PINK1, Parkin, sequestome 1 (P62), and microtubule-associated proteins1A/1B light chain 3B (MAP1LC3B). RESULTS: The MMP was significantly decreased and the activity of CK-MB, cTnI, and M-GOT significantly increased in each experimental group (low Se group, low protein group, low Se + low protein group and corn from KD area group) compared with the control group (P<0.05 for all). The mRNA and protein expression levels of PINK1, Parkin and MAP1LC3B were profoundly increased, and those of P62 markedly decreased in the experimental groups compared with the control group (P<0.05 for all). CONCLUSION: Low Se and low protein levels exacerbate myocardial damage in KD by affecting the PINK1/Parkin-mediated mitochondrial autophagy pathway.

The therapeutic effect of exosomal lncRNA MSTRG.91634.7 on mitochondrial dysfunction during SiO2-induced lung fibrosis.

Long-term silica (SiO2) exposure led to irreversible lung fibrosis, in which epithelial-mesenchymal transition (EMT) played an essential role. A novel lncRNA MSTRG.91634.7 in the peripheral exosomes of silicosis patients was reported in our previous study, which could remold the pathological process of silicosis. However, whether its regulatory role on the development of silicosis was related to EMT process is unclear, and its mechanism remains to be further studied. In this study, up-regulating lncRNA MSTRG91634.7 restricted SiO2-activated EMT and restored mitochondrial homeostasis binding to PINK1 in vitro. Moreover, overexpressing PINK1 could inhibit SiO2-activated EMT in pulmonary inflammation and fibrosis in mice. Meanwhile, PINK1 contributed to restoring the SiO2-induced mitochondrial dysfunction in mice lung. Our results revealed that exosomal lncRNA MSTRG.91634.7 from macrophages could restore mitochondrial homeostasis to restrict the SiO2-activated EMT by binding to PINK1 during pulmonary inflammation and fibrosis due to SiO2 exposure.

Heme oxygenase­1 inhibits renal tubular epithelial cell pyroptosis by regulating mitochondrial function through PINK1.

Endotoxin-induced acute kidney injury (AKI) is commonly observed in clinical practice. Renal tubular epithelial cell (RTEC) pyroptosis is one of the main factors leading to the development of endotoxin-induced AKI. Mitochondrial dysfunction can lead to pyroptosis. However, the biological pathways involved in the potential lipopolysaccharide (LPS)-induced pyroptosis of RTECs, notably those associated with mitochondrial dysfunction, are poorly understood. Previous studies have demonstrated that heme oxygenase (HO)-1 confers cell protection via the induction of PTEN-induced putative kinase 1 (PINK1) expression through PTEN to regulate mitochondrial fusion/fission during endotoxin-induced AKI in vivo. Therefore, the present study investigated the role of HO-1/PINK1 in maintaining mitochondrial function and inhibiting the pyroptosis of RTECs exposed to LPS. Primary cultures of RTECs were obtained from wild-type (WT) and PINK1-knockout (PINK1KO) rats. An in vitro model of endotoxin-associated RTEC injury was established following treatment of the cells with LPS. The WT RTECs were divided into the control, LPS, Znpp + LPS and Hemin + LPS groups, and the PINK1KO RTECs were divided into the control, LPS and Hemin + LPS groups. RTECs were exposed to LPS for 6 h to assess cell viability, inflammation, pyroptosis and mitochondrial function. In the LPS-treated RTECs, the mRNA and protein expression levels of HO-1 and PINK1 were upregulated. Cell viability, adenosine triphosphate (ATP) levels and the mitochondrial oxygen consumption rate were decreased, whereas the inflammatory response, pyroptosis and mitochondrial reactive oxygen species (ROS) levels were increased. The cell inflammatory response and the induction of pyroptosis were inhibited, whereas the levels of mitochondrial ROS were decreased. In addition, the cell viability and ATP levels were increased in the WT RTECs following the upregulation of HO-1 expression. These effects were reversed by the downregulation of HO-1 expression. However, no statistically significant differences were noted between the LPS and the Hemin + LPS groups in the PINK1KO RTECs. Collectively, the findings of the present study indicate that HO-1 inhibits inflammation and regulates mitochondrial function by inhibiting the pyroptosis of LPS-exposed RTECs via PINK1.

MicroRNA-593-5p contributes to cell death following exposure to 1-methyl-4-phenylpyridinium by targeting PTEN-induced putative kinase 1.

Neurodegenerative diseases are characterized by a decline in neuronal function and structure, leading to neuronal death. Understanding the molecular mechanisms of neuronal death is crucial for developing therapeutics. MiRs are small noncoding RNAs that regulate gene expression by degrading target mRNAs or inhibiting translation. MiR dysregulation has been linked to many neurodegenerative diseases, but the underlying mechanisms are not well understood. As mitochondrial dysfunction is one of the common molecular mechanisms leading to neuronal death in many neurodegenerative diseases, here we studied miRs that modulate neuronal death caused by 1-methyl-4-phenylpyridinium (MPP+), an inhibitor of complex I in mitochondria. We identified miR-593-5p, levels of which were increased in SH-SY5Y human neuronal cells, after exposure to MPP+. We found that intracellular Ca2+, but not of reactive oxygen species, mediated this miR-593-5p increase. Furthermore, we found the increase in miR-593-5p was due to enhanced stability, not increased transcription or miR processing. Importantly, we show the increase in miR-593-5p contributed to MPP+-induced cell death. Our data revealed that miR-593-5p inhibits a signaling pathway involving PTEN-induced putative kinase 1 (PINK1) and Parkin, two proteins responsible for the removal of damaged mitochondria from cells, by targeting the coding sequence of PINK1 mRNA. Our findings suggest that miR-593-5p contributes to neuronal death resulting from MPP+ toxicity, in part, by impeding the PINK1/Parkin-mediated pathway that facilitates the clearance of damaged mitochondria. Taken together, our observations highlight the potential significance of inhibiting miR-593-5p as a therapeutic approach for neurodegenerative diseases.

[Effect on Danggui Shaoyao Powder on mitophagy in rat model of Alzheimer's disease based on PINK1-Parkin pathway].

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.

PINK1-mediated mitophagy contributes to glucocorticoid-induced cathepsin K production in osteocytes.

Background: Glucocorticoid (GC) is one of frequently used anti-inflammatory agents, but its administration is unfortunately accompanied with bone loss. Although sporadic studies indicated that osteocytes are subject to a series of pathological changes under GC stress, including overexpression of cathepsin K, the definite role of osteocytes in GC-induced bone loss remains largely unclear. Methods: Gene expression of Ctsk and protein levels of cathepsin K were assessed in MLO-Y4 cell lines exposed to dexamethasone (Dex) of different time (0, 12, 24 hours) and dose (0, 10-8 and 10-6 M) courses by RT-qPCR and western blotting, respectively. Confocal imaging and immunostaining were then performed to evaluate the effects of osteocyte-derived cathepsin K on type I collagen in a primary osteocyte ex vivo culture system. MitoTracker Red was used to stain mitochondria for mitochondria morphology assessment and JC-1 assay was employed to evaluate the mitochondria membrane potential in MLO-Y4 cells following Dex treatment. Activation of PINK1-mediated mitophagy was evaluated by immunostaining of the PINK1 protein and CytoID assay. Mdivi-1 was used to inhibit mitophagy and siRNAs were used for the inhibition of Pink1 and Atg5. Results: GC triggered osteocytes to produce excessive cathepsin K which in turn led to the degradation of type I collagen in the extracellular matrix in a primary osteocyte ex vivo culture system. Meanwhile, GC administration increased mitochondrial fission and membrane depolarization in osteocytes. Further, the activation of PINK1-mediated mitophagy was demonstrated to be responsible for the diminishment of dysfunctional mitochondria in osteocytes. Examination of relationship between mitophagy and cathepsin K production revealed that inhibition of mitophagy via knocking down Pink1 gene abolished the GC-triggered cathepsin K production. Interestingly, GC's activation effect towards cathepsin K via mitophagy was found to be independent on the canonical autophagy as this effect was not impeded when inhibiting the canonical autophagy via Atg5 suppression. Conclusion: GC-induced PINK1-mediated mitophagy substantially modulates the production of cathepsin K in osteocytes, which could be an underlying mechanism by which osteocytes contribute to the extracellular matrix degradation during bone loss. The Translational potential of this article: Findings of the current study indicate a possible role of osteocyte mitophagy in GC-induced bone loss, which provides a potential therapeutic approach to alleviate GC-induced osteoporosis by targeting PINK1-mediated osteocytic mitophagy.

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.

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.

Exploring the mechanism of anti-hereditary Parkinson's disease of baicalein based on PINK1 RNAi Drosophila model / 药学学报

The aim of this study was to investigate the effect of baicalein on a Drosophila model of hereditary Parkinson's disease caused by gene mutations and to preliminarily elucidate the mechanism of baicalein in delaying hereditary Parkinson's disease. In this paper, PTEN-induced putative kinase 1 (PINK1)-RNAi Parkinson's Drosophila were used as the model group and wild-type Drosophila w1118 were used as the control group. Different doses of baicalein and Madopa were administered to the model group to observe their effects on the life span, motor ability, the abnormal rate of wings, dopamine content and dopaminergic neurons of PINK1-RNAi Parkinson's Drosophila and their effects on mitochondrial dysfunction including adenosine triphosphate (ATP), mitochondrial DNA (mtDNA) and reactive oxygen species (ROS) content. The results showed that the effective administration doses of baicalein were 0.8 mg·mL-1 for low concentration, 1.6 mg·mL-1 for medium concentration and 3.2 mg·mL-1 for high concentration, and the optimal administration dose of the positive drug Madopa was 0.1 μg·mL-1. Baicalein and Madopa could significantly improve the life span, exercise ability and reduce the abnormal rate of wings of PINK1-RNAi male Drosophila (P < 0.05), and low dose baicalein showed the best effect; baicalein could improve the loss of dopaminergic neurons, and the effects of low dose and high dose were the best, but Madopa showed no significant effect; baicalein and Madopa had no significant effect on dopamine content (P > 0.05). Baicalein and Madopa could increase the ATP content of PINK1-RNAi male Drosophila (P < 0.05), and low dose baicalein showed the best effect; middle dose baicalein could significantly increase the mtDNA content of PINK1-RNAi male Drosophila (P < 0.05), but Madopa had no significant effect; baicalein and Madopa had no significant effect on ROS content (P > 0.05).

Spontaneous Object Exploration in a Recessive Gene Knockout Model of Parkinson's Disease: Development and Progression of Object Recognition Memory Deficits in Male Pink1-/- Rats.

Cognitive impairments appear at or before motor signs in about one third of patients with Parkinson's disease (PD) and have a cumulative prevalence of roughly 80% overall. These deficits exact an unrelenting toll on patients' quality and activities of daily life due in part to a lack of available treatments to ameliorate them. This study used three well-validated novel object recognition-based paradigms to explore the suitability of rats with knockout of the PTEN-induced putative kinase1 gene (Pink1) for investigating factors that induce cognitive decline in PD and for testing new ways to mitigate them. Longitudinal testing of rats from 3-9 months of age revealed significant impairments in male Pink1-/- rats compared to wild type controls in Novel Object Recognition, Novel Object Location and Object-in-Place tasks. Task-specific differences in the progression of object discrimination/memory deficits across age were also seen. Finally, testing using an elevated plus maze, a tapered balance beam and a grip strength gauge showed that in all cases recognition memory deficits preceded potentially confounding impacts of gene knockout on affect or motor function. Taken together, these findings suggest that knockout of the Pink1 gene negatively impacts the brain circuits and/or neurochemical systems that support performance in object recognition tasks. Further investigations using Pink1-/- rats and object recognition memory tasks should provide new insights into the neural underpinnings of the visual recognition memory and visuospatial information processing deficits that are often seen in PD patients and accelerate the pace of discovery of better ways to treat them.

IL-17A promotes lung fibrosis through impairing mitochondrial homeostasis in type II alveolar epithelial cells.

The dysfunction of type II alveolar epithelial cells (AECIIs), mainly manifested by apoptosis, has emerged as a major component of idiopathic pulmonary fibrosis (IPF) pathophysiology. A pivotal mechanism leading to AECIIs apoptosis is mitochondrial dysfunction. Recently, interleukin (IL)-17A has been demonstrated to have a pro-fibrotic role in IPF, though the mechanism is unclear. In this study, we report enhanced expression of IL-17 receptor A (IL-17RA) in AECIIs in lung samples of IPF patients, which may be related to the accumulation of mitochondria in AECIIs of IPF. Next, we investigated this relationship in bleomycin (BLM)-induced PF murine model. We found that IL-17A knockout (IL-17A-/- ) mice exhibited decreased apoptosis levels of AECIIs. This was possibly a result of the recovery of mitochondrial morphology from the improved mitochondrial dynamics of AECIIs, which eventually contributed to alleviating lung fibrosis. Analysis of in vitro data indicates that IL-17A impairs mitochondrial function and mitochondrial dynamics of mouse primary AECIIs, further promoting apoptosis. PTEN-induced putative kinase 1 (PINK1)/Parkin signal-mediated mitophagy is an important aspect of mitochondria homeostasis maintenance. Our data demonstrate that IL-17A inhibits mitophagy and promotes apoptosis of AECIIs by decreasing the expression levels of PINK1. We conclude that IL-17A exerts its pro-fibrotic effects by inducing mitochondrial dysfunction in AECIIs by disturbing mitochondrial dynamics and inhibiting PINK1-mediated mitophagy, thereby leading to apoptosis of AECIIs.

The involvement of Parkin-dependent mitophagy in the anti-cancer activity of Ginsenoside.

Colon cancer, the third most frequent occurred cancer, has high mortality and extremely poor prognosis. Ginsenoside, the active components of traditional Chinese herbal medicine Panax ginseng, exerts antitumor effect in various cancers, including colon cancer. However, the detailed molecular mechanism of Ginsenoside in the tumor suppression have not been fully elucidated. Here, we chose the representative ginsenoside Rg3 and reported for the first time that Rg3 induces mitophagy in human colon cancer cells, which is responsible for its anticancer effect. Rg3 treatment leads to mitochondria damage and the formation of mitophagosome; when autophagy is inhibited, the clearance of damaged mitochondria can be reversed. Next, our results showed that Rg3 treatment activates the PINK1-Parkin signaling pathway and recruits Parkin and ubiquitin proteins to mitochondria to induce mitophagy. GO analysis of Parkin targets showed that Parkin interacts with a large number of mitochondrial proteins and regulates the molecular function of mitochondria. The cellular energy metabolism enzyme GAPDH is validated as a novel substrate of Parkin, which is ubiquitinated by Parkin. Moreover, GAPDH participates in the Rg3-induced mitophagy and regulates the translocation of Parkin to mitochondria. Functionally, Rg3 exerts the inhibitory effect through regulating the nonglycolytic activity of GAPDH, which could be associated with the cellular oxidative stress. Thus, our results revealed GAPDH ubiquitination by Parkin as a crucial mechanism for mitophagy induction that contributes to the tumor-suppressive function of ginsenoside, which could be a novel treatment strategy for colon cancer.

CircRNA608-microRNA222-PINK1 axis regulates the mitophagy of hepatic stellate cells in NASH related fibrosis.

BACKGROUND: Increasing evidences have confirmed the relationship between mitophagy and nonalcoholic steatohepatitis (NASH). The exact mechanism of upstream circular RNAs (circRNAs) regulating PTEN-induced putative kinase 1 (PINK1) mediated mitophagy and its contribution to NASH-related liver fibrosis was explored in our study. METHODS: Primary hepatic stellate cells (PHSCs) from C57BL/6 mice transfected with small interfering RNAs against PINK1 (si-PINK1) and negative control (si-NC) were prepared to perform circRNA sequence. Differentially expressed circRNAs, bioinformatic analysis and predicting software were performed to select axis of circ608/miR-222/PINK1. The expressions of circ608/miR-222/PINK1 were verified by RT-qPCR. The mitochondrial function was evaluated by immunofluorescence staining of COX4 and LC3B. RESULTS: PINK1-mediated mitophagy was inhibited in NASH-related liver fibrosis mice. CircRNA sequence revealed there were 37 DE-circRNAs between si-PINK1 PHSCs and si-NC PHSCs. Bioinformatic analysis showed these DE-circRNAs were related to enriched signaling pathways (such as Wnt, Rap1, mTOR, Hippo) regulating liver fibrosis and mitophagy. Circ608 was significantly down-regulated in lipotoxic HSCs and in livers of NASH-related liver fibrosis mice. MiR222 was identified to be the target miRNA of circ608 and was negatively regulated by circ608 in lipotoxic HSCs. MiR222 also had a binding site with PINK1 and could negatively regulate PINK1. So, the axis of circ608-miR222-PINK1 was proved to participate in NASH-related liver fibrosis by regulating mitophagy. These results illustrated that circ608 might promote PINK1-mediated mitophagy though inhibiting miR222 in lipotoxic HSCs. CONCLUSION: Circ608 could promote PINK1-mediated mitophagy of HSCs though inhibiting miR222 in NASH-related liver fibrosis.

Therapeutic targeting of mitophagy in Parkinson's disease.

Parkinson's disease is a neurodegenerative disorder characterised by cardinal motor symptoms and a diverse range of non-motor disorders in patients. Parkinson's disease is the fastest growing neurodegenerative condition and was described for the first time over 200 years ago, yet there are still no reliable diagnostic markers and there are only treatments that temporarily alleviate symptoms in patients. Early-onset Parkinson's disease is often linked to defects in specific genes, including PINK1 and Parkin, that encode proteins involved in mitophagy, the process of selective autophagic elimination of damaged mitochondria. Impaired mitophagy has been associated with sporadic Parkinson's and agents that damage mitochondria are known to induce Parkinson's-like motor symptoms in humans and animal models. Thus, modulating mitophagy pathways may be an avenue to treat a subset of early-onset Parkinson's disease that may additionally provide therapeutic opportunities in sporadic disease. The PINK1/Parkin mitophagy pathway, as well as alternative mitophagy pathways controlled by BNIP3L/Nix and FUNDC1, are emerging targets to enhance mitophagy to treat Parkinson's disease. In this review, we report the current state of the art of mitophagy-targeted therapeutics and discuss the approaches being used to overcome existing limitations to develop innovative new therapies for Parkinson's disease. Key approaches include the use of engineered mouse models that harbour pathogenic mutations, which will aid in the preclinical development of agents that can modulate mitophagy. Furthermore, the recent development of chimeric molecules (AUTACs) that can bypass mitophagy pathways to eliminate damaged mitochondria thorough selective autophagy offer new opportunities.

PTEN-Induced Putative Kinase 1 Dysfunction Accelerates Synucleinopathy.

BACKGROUND: Mutations in PTEN-induced putative kinase 1 (PINK1) cause autosomal recessive Parkinson's disease (PD) and contribute to the risk of sporadic PD. However, the relationship between PD-related PINK1 mutations and alpha-synuclein (α-syn) aggregation-a main pathological component of PD-remains unexplored. OBJECTIVE: To investigate whether α-syn pathology is exacerbated in the absence of PINK1 after α-syn preformed fibril (PFF) injection in a PD mouse model and its effects on neurodegeneration. METHODS: In this study, 10-week-old Pink1 knockout (KO) and wildtype (WT) mice received stereotaxic unilateral striatal injection of recombinant mouse α-syn PFF. Then, α-syn pathology progression, inflammatory responses, and neurodegeneration were analyzed via immunohistochemistry, western blot analysis, and behavioral testing. RESULTS: After PFF injection, the total α-syn levels significantly increased, and pathological α-syn was markedly aggregated in Pink1 KO mice compared with Pink1 WT mice. Then, earlier and more severe neuronal loss and motor deficits occurred. Moreover, compared with WT mice, Pink1 KO mice had evident microglial/astrocytic immunoreactivity and prolonged astrocytic activation, and a higher rate of protein phosphatase 2A phosphorylation, which might explain the greater α-syn aggravation and neuronal death. CONCLUSION: The loss of Pink1 function accelerated α-syn aggregation, accumulation and glial activation, thereby leading to early and significant neurodegeneration and behavioral impairment in the PD mouse model. Therefore, our findings support the notion that PINK1 dysfunction increases the risk of synucleinopathy.

Histone deacetylase inhibitors inhibit cervical cancer growth through Parkin acetylation-mediated mitophagy.

Parkin, an E3 ubiquitin ligase, plays a role in maintaining mitochondrial homeostasis through targeting damaged mitochondria for mitophagy. Accumulating evidence suggests that the acetylation modification of the key mitophagy machinery influences mitophagy level, but the underlying mechanism is poorly understood. Here, our study demonstrated that inhibition of histone deacetylase (HDAC) by treatment of HDACis activates mitophagy through mediating Parkin acetylation, leading to inhibition of cervical cancer cell proliferation. Bioinformatics analysis shows that Parkin expression is inversely correlated with HDAC2 expression in human cervical cancer, indicating the low acetylation level of Parkin. Using mass spectrometry, Parkin is identified to interact with two upstream molecules, acetylase acetyl-CoA acetyltransferase 1 (ACAT1) and deacetylase HDAC2. Under treatment of suberoylanilide hydroxamic acid (SAHA), Parkin is acetylated at lysine residues 129, 220 and 349, located in different domains of Parkin protein. In in vitro experiments, combined mutation of Parkin largely attenuate the interaction of Parkin with PTEN induced putative kinase 1 (PINK1) and the function of Parkin in mitophagy induction and tumor suppression. In tumor xenografts, the expression of mutant Parkin impairs the tumor suppressive effect of Parkin and decreases the anticancer activity of SAHA. Our results reveal an acetylation-dependent regulatory mechanism governing Parkin in mitophagy and cervical carcinogenesis, which offers a new mitophagy modulation strategy for cancer therapy.