Role of mitophagy in the development and progression of liver-related diseases / 临床肝胆病杂志

Mitophagy is a type of selective autophagy during which cells specifically remove damaged mitochondria in response to nutrient deficiency or external stimulation and thus maintain the integrity of mitochondrial function and cellular homeostasis. In recent years， a large number of studies have shown that dysfunction of mitophagy is closely associated with the development and progression of various liver-related diseases such as nonalcoholic fatty liver disease， drug-related liver injury， viral hepatitis， and hepatocellular carcinoma. This article summarizes the specific mechanisms of mitophagy in regulating liver-related diseases and further elaborates on the potential therapeutic targets of mitophagy in liver-related diseases， in order to provide more effective therapeutic strategies for the clinical treatment of liver diseases.

Mechanism of oxymatrine promoting the apoptosis of osteosarcoma MG63 cell line through mitophagy mediated by COX-2/PINK1/Parkin signaling pathway / 中国药房

OBJECTIVE To study the mechanism of oxymatrine inducing apoptosis of osteosarcoma MG63 cell line based on mitophagy mediated by cyclooxygenase-2 （COX-2）/PTEN-induced putative kinase-1 （PINK1）/Parkinson disease protein-2 （Parkin） signaling pathway. METHODS MG63 cells were treated with 2.0， 4.0， 8.0 mg/mL oxymatrine and 6 μmol/L 5-fluorouracil， then the apoptotic rate， the expression of apoptosis-related proteins [B-cell lymphoma-2 （Bcl-2）， Bcl-2 related X protein （Bax）]， the proportion of decrease in mitochondrial membrane potential， the level of mitophagy as well as the protein expressions of PINK1， Parkin， and microtubule-associated protein 1 light chain-3Ⅱ （LC3-Ⅱ） were detected. PINK1 small interfering RNA （siRNA） was adopted to intervene in the expression of PINK1， the cells were divided into control group， PINK1 siRNA group， oxymatrine group， and PINK1 siRNA+oxymatrine group； the protein expressions of PINK1， Parkin， and LC3-Ⅱ， the proportion of decrease in mitochondrial membrane potential （MMP） as well as apoptotic rate were detected. The lentivirus infection technique was used to overexpress COX-2， the cells were divided into control group， oxymatrine group， COX-2 group， and COX-2+oxymatrine group. The protein expressions of COX-2， PINK1， and Parkin， as well as the proportion of decrease in MMP were detected. RESULTS After being treated with oxymatrine， the apoptotic rate， the protein expressions of Bax， PINK1， Parkin， and LC3-Ⅱ， the level of mitophagy as well as the proportion of decrease in MMP were significantly increased （P＜0.05）， while the protein expression of Bcl-2 was significantly decreased （P＜0.05）. Compared with the oxymatrine group， the protein expressions of PINK1， Parkin， and LC3-Ⅱ， apoptotic rate and the proportion of decrease in MMP were significantly decreased in PINK1 siRNA+oxymatrine group （P＜0.05）. Compared with the oxymatrine group， the protein expression of COX-2 in the COX-2+oxymatrine group was increased significantly （P＜0.05）， while the protein expressions of PINK1 and Parkin as well as the proportion of 526087266@qq.com decrease in MMP were decreased significantly （P＜0.05）. CONCLUSIONS Oxymatrine can mediate the overactivity of mitophagy based on the PINK1/Parkin signaling pathway by inhibiting COX-2 expression， thus promoting the apoptosis of the MG63 osteosarcoma cell line.

The neuroprotective effects of Haikun Shenxi capsule medicated serum on N2a/APP695 cells based on PINKl-Parkin mitophagy pathway / 中国药理学通报

Aim To research the neuroprotective effect of Haikun Shenxi (HKSX) medicated serum on N2a/ App695 cells and the underlying mechanism. Methods HKSX medicated serum was prepared and carbohydrate components in it was analyzed using high performance thin layer chromatography (HPTLC) . N2a/ App695 cells were intervened with HKSX medicated serum, the cytotoxicity of HKSX medicated serum was measured by MTT; AP[_

Research progress of Parkin protein regulating mitochondrial homeostasis through ubiquitination in cardiovascular diseases / 中国药理学通报

In addition to providing energy for cells, mitochondria also participate in calcium homeostasis, cell information transfer, cell apoptosis, cell growth and differentiation. Therefore, maintaining mitochondrial homeostasis is very crucial for the body to carry out normal life activities. Ubiquitination, a post-translational modification of proteins, is involved in various physiological and pathological processes of cells by regulating mitochondrial homeostasis. However, the mechanism by which ubiquitination regulates mitochondrial homeostasis has not been summarized, especially the effect of Parkin protein on cardiovascular diseases. In this paper, the specific mechanism of mitochondrial homeostasis regulated by ubiquitination of Parkin protein is discussed, and the influence of mitochondrial homeostasis imbalance on cardiovascular diseases is reviewed, with a view to providing potential therapeutic strategies for the clinical treatment of cardiovascular diseases.

Effect of Qingshen granules on miR-23b and PINKl/Parkin pathway in rat NRK-52E cell transdifferentiation model / 中国药理学通报

Aim To investigate the targeting mechanism of miR-23b on PINKl/Parkin pathway in transdifferentiation of NRK-52E cellsinduced by TGF-β1, and to elucidate the intervention mechanism of Qingshen granules drug-containing serum on NRK-52E cell transdifferentiation. Methods Ultra-high performance liquid chromatography ( UPLC ) fingerprinting method was used to analyze Qingshen granules. The NRK-52E transdifferentiation model induced by TGF-β1 was constructed. The NRK-52E cells were divided into simulated no-load control group, miR-23b-5p simulated group, inhibitor no-load control group, and miR-23b-5p inhibitor group, after transfection with siRNA, and the effect of miR-23b-5p on PINK1 expression was ob-served. The NRK-52E cells were then divided into normal group, TGF-(31 group, Qingshen granule group, miR-23 b-mimic group, miR-23 b-mimic group, and miR-23b-mimic + Qingshen granule group. Western blot was used to detect the expression of Pinkl, Parkin, LC3 n, Beclin-1, P62 and a-SMA proteins, and RT- PCR was used to detect the expression of miR-23 b-5p, Pinkl, Parkin, Beclin-1 and a-SMA mRNA in NRK- 52E cells. Dual-Luciferase Reporter gene experiment was used to detect the targeting relationship between miR-23b-5p and PINKL Results UPLC fingerprinting method found 11 active components in Qingshen granules. After overexpression of miR-23b-5p, the expression of PINkl mRNA significantly increased (P 0. 05 ). The experimental results showed that the expressions of miR- 23b-5p, Pinkl, Parkin, Beclin-1, LC3 II and LC3 II/ I ratio in TGF-β1 group were significantly lower than those in normal group, but the expressions of P62 and a-SMA were significantly higher than those in normal group ( P <0.05). The expressions of miR-23 b-5 p, Pinkl, Parkin, Beclin-1, LC3 II and LC3 11/ I ratio in Qingshen granule group and miR-23 b-mimic group were significantly higher than those in TGF-β1 group, and the expressions of P62 and a-SMA were significantly lower than those in TGF-β1 group (P < 0. 05 ). The performance of miR-23 b-mimic + Qingshen granule group was better than that of miR-23 b-mimic group (P < 0. 05 ). Conclusions Qingshen granules can up- regulate the expression of miR-23b-5p in NRK-52E cellsand inhibit the transdifferentiation process of NRK- 52E cells by enhancing the mitochondrial autophagy activity mediated by PINKl/Parkin pathway.

Berberine interferes with RSV infection of HEp-2 cells by inducing mitophagy autophagy / 中国药理学通报

Aim To explore the effect of berberine (B E) on RSV infected HEp-2 cells and the related mechanism. Methods HEp-2 cells were infected with RSV and treated with BE. Cell viability was assessed using the CCK-8 assay. Protein expression levels of NLRP3, ASC, caspase-1, PINK1, Parkin, Beclinl, p62, LC3 I,LC3 II,and BNIP3 in HEp-2 cells were detected by Western blot. The secretion level of IL-1 p in HEp-2 cells was measured using ELISA. Apoptosis rate and mitochondrial membrane potential of HEp-2 cells were examined by flow cytometry. Mitochondrial ROS (mtROS) in HEp-2 cells was detected through MitoSOX staining. Colocalization of mitochondria and autophagosomes in HEp-2 cells was investigated using immunofluorescence staining. Cyclosporin A was used for validation experiments. Results BE could significantly improve the activity of RSV-infected HEp-2 cells,reduce the apoptosis rate (P < 0. 05), and decrease the activation level of NLRP3 inflammasomes and IL-lp level (P <0. 05); BE improved mitochondrial function by increasing mitochondrial membrane potential and ATP levels,and reduced mtROS. BE significantly promoted the colocalization of mitochondria-autophagosome in RSV infected cells, inducing PINK1/ Parkin and BNIP3 to mediate mitochondrial autophagy; cyclosporine A aggravated RSV infection. Conclusions BE has protective effects on HEp-2 cells infected by RSV. The mechanism may be related to the inhibitory effect of BE on the production of mtROS and the activation of NLRP3 inflammasomes by inducing PINK1/ Parkin and BNIP3-mediated mitochondrial autophagy.

High-throughput screening of novel TFEB agonists in protecting against acetaminophen-induced liver injury in mice

Macroautophagy (referred to as autophagy hereafter) is a major intracellular lysosomal degradation pathway that is responsible for the degradation of misfolded/damaged proteins and organelles. Previous studies showed that autophagy protects against acetaminophen (APAP)-induced injury (AILI) via selective removal of damaged mitochondria and APAP protein adducts. The lysosome is a critical organelle sitting at the end stage of autophagy for autophagic degradation via fusion with autophagosomes. In the present study, we showed that transcription factor EB (TFEB), a master transcription factor for lysosomal biogenesis, was impaired by APAP resulting in decreased lysosomal biogenesis in mouse livers. Genetic loss-of and gain-of function of hepatic TFEB exacerbated or protected against AILI, respectively. Mechanistically, overexpression of TFEB increased clearance of APAP protein adducts and mitochondria biogenesis as well as SQSTM1/p62-dependent non-canonical nuclear factor erythroid 2-related factor 2 (NRF2) activation to protect against AILI. We also performed an unbiased cell-based imaging high-throughput chemical screening on TFEB and identified a group of TFEB agonists. Among these agonists, salinomycin, an anticoccidial and antibacterial agent, activated TFEB and protected against AILI in mice. In conclusion, genetic and pharmacological activating TFEB may be a promising approach for protecting against AILI.

Cholic and deoxycholic acids induce mitochondrial dysfunction, impaired biogenesis and autophagic flux in skeletal muscle cells

BACKGROUND: Skeletal muscle is sensitive to bile acids (BA) because it expresses the TGR5 receptor for BA. Cholic (CA) and deoxycholic (DCA) acids induce a sarcopenia-like phenotype through TGR5-dependent mechanisms. Besides, a mouse model of cholestasis-induced sarcopenia was characterised by increased levels of serum BA and muscle weakness, alterations that are dependent on TGR5 expression. Mitochondrial alterations, such as decreased mitochondrial potential and oxygen consumption rate (OCR), increased mitochondrial reactive oxygen species (mtROS) and unbalanced biogenesis and mitophagy, have not been studied in BA-induced sarcopenia.METHODS: We evaluated the effects of DCA and CA on mitochondrial alterations in C2C12 myotubes and a mouse model of cholestasis-induced sarcopenia. We measured mitochondrial mass by TOM20 levels and mitochondrial DNA; ultrastructural alterations by transmission electronic microscopy; mitochondrial biogenesis by PGC-1α plasmid reporter activity and protein levels by western blot analysis; mitophagy by the co-localisation of the MitoTracker and LysoTracker fluorescent probes; mitochondrial potential by detecting the TMRE probe signal; protein levels of OXPHOS complexes and LC3B by western blot analysis; OCR by Seahorse measures; and mtROS by MitoSOX probe signals. RESULTS: DCA and CA caused a reduction in mitochondrial mass and decreased mitochondrial biogenesis. Interestingly, DCA and CA increased LC3II/LC3I ratio and decreased autophagic flux concordant with raised mitophagosome-like structures. In addition, DCA and CA decreased mitochondrial potential and reduced protein levels in OXPHOS complexes I and II. The results also demonstrated that DCA and CA decreased basal, ATP-linked, FCCP-induced maximal respiration and spare OCR. DCA and CA also reduced the number of cristae. In addition, DCA and CA increased the mtROS. In mice with cholestasis-induced sarcopenia, TOM20, OXPHOS complexes I, II and III, and OCR were diminished. Interestingly, the OCR and OXPHOS complexes were correlated with muscle strength and bile acid levels. CONCLUSION: Our results showed that DCA and CA decreased mitochondrial mass, possibly by reducing mitochondrial biogenesis, which affects mitochondrial function, thereby altering potential OCR and mtROS generation. Some mitochondrial alterations were also observed in a mouse model of cholestasis-induced sarcopenia characterised by increased levels of BA, such as DCA and CA.

O Pré-Condicionamento com Dexmedetomidina Atenua a Lesão de Isquemia/Reperfusão Miocárdica em Ratos, Suprimindo a Mitofagia Via Ativação do Receptor Α2-Adrenérgico / Dexmedetomidine Preconditioning Attenuates Myocardial Ischemia/Reperfusion Injury in Rats by Suppressing Mitophagy Via Activating Α2-Adrenergic Receptor

Resumo Fundamento A dexmedetomidina (DEX), um agonista específico do receptor α2-adrenérgico, é protetora contra lesão de isquemia/reperfusão miocárdica (I/R). No entanto, a associação entre a cardioproteção induzida pelo pré-condicionamento DEX e a supressão da mitofagia permanece pouco clara. Objetivo Portanto, nosso objetivo foi investigar se o pré-condicionamento com DEX alivia a I/R, suprimindo a mitofagia via ativação do receptor α2-adrenérgico. Método Sessenta corações de ratos isolados foram tratados com ou sem DEX antes de induzir isquemia e reperfusão; um antagonista do receptor α2-adrenérgico, a ioimbina (YOH), também foi administrado antes da isquemia, isoladamente ou com DEX. A frequência cardíaca (FC), pressão diastólica do ventrículo esquerdo (PDVE), pressão diastólica final do ventrículo esquerdo (PDFVE), taxa máxima e mínima de desenvolvimento da pressão ventricular esquerda (±dp/dtmax) e tamanho do infarto do miocárdio foram medidos. A ultraestrutura mitocondrial e as autofagossomas foram avaliadas por microscopia eletrônica de transmissão. O potencial de membrana mitocondrial e os níveis de espécies reativas de oxigênio (ROS) foram medidos usando os ensaios JC-1 e diacetato de diclorodi hidrofluoresceína, respectivamente. Os níveis de expressão das proteínas associadas à mitofagia Beclin1, relação LC3II/I, p62, PINK1 e Parkin foram detectados por western blotting. Resultados Em comparação com o grupo controle, no grupo isquemia/reperfusão, a FC, PDVE e ±dp/dtmax foram notavelmente diminuídas (p<0,05), enquanto os tamanhos da PDFVE e do infarto aumentaram significativamente (p<0,05). O pré-condicionamento com DEX melhorou significativamente a disfunção cardíaca, reduziu o tamanho do infarto do miocárdio, manteve a integridade estrutural mitocondrial, aumentou o potencial de membrana mitocondrial, inibiu a formação de autofagossomas e diminuiu a produção de ROS e a relação Beclin1, relação LC3II/I, expressão PINK1, Parkin e p62(p<0,05). Quando DEX e YOH foram combinados, o YOH cancelou o efeito da DEX, enquanto o uso de YOH sozinha não teve efeito. Conclusão Portanto, o pré-condicionamento DEX foi cardioprotetor contra I/R em ratos, suprimindo a mitofagia por meio da ativação do receptor α2-adrenérgico.

Abstract Background Dexmedetomidine (DEX), a specific α2-adrenergic receptor agonist, is protective against myocardial ischemia/reperfusion injury (MIRI). However, the association between DEX preconditioning-induced cardioprotection and mitophagy suppression remains unclear. Objective Hence, we aimed to investigate whether DEX preconditioning alleviates MIRI by suppressing mitophagy via α2-adrenergic receptor activation. Method Sixty isolated rat hearts were treated with or without DEX before inducing ischemia and reperfusion; an α2-adrenergic receptor antagonist, yohimbine (YOH), was also administered before ischemia, alone or with DEX. The heart rate (HR), left ventricular diastolic pressure (LVDP), left ventricular end-diastolic pressure (LVEDP), maximal and minimal rate of left ventricular pressure development (±dp/dtmax), and myocardial infarction size were measured. The mitochondrial ultrastructure and autophagosomes were assessed using transmission electron microscopy. Mitochondrial membrane potential and reactive oxygen species (ROS) levels were measured using JC-1 and dichloride hydrofluorescein diacetate assays, respectively. The expression levels of the mitophagy-associated proteins Beclin1, LC3II/I ratio, p62, PINK1, and Parkin were detected by western blotting. Results Compared with the control group, in the ischemia/reperfusion group, the HR, LVDP, and ±dp/dtmax were remarkably decreased (p< 0.05), whereas LVEDP and infarct sizes were significantly increased (p< 0.05). DEX preconditioning significantly improved cardiac dysfunction reduced myocardial infarction size, maintained mitochondrial structural integrity, increased mitochondrial membrane potential, inhibited autophagosomes formation, and decreased ROS production and Beclin1, LC3II/I ratio, PINK1, Parkin, and p62 expression(p< 0.05). When DEX and YOH were combined, YOH canceled the effect of DEX, whereas the use of YOH alone had no effect. Conclusion Therefore, DEX preconditioning was cardioprotective against MIRI in rats by suppressing mitophagy via α2-adrenergic receptor activation.

Advance of mitophagy in diabetic cardiomyopathy / 中华内分泌代谢杂志

Diabetic cardiomyopathy is a myocardial complication associated with abnormal glucose metabolism and dyslipidiaemia, which increases the risk of death and heart failure in diabetic patients. Mitochondrial dysfunction is involved in the occurrence and development of diabetic cardiomyopathy. Recent studies have confirmed that scavenging damaged mitochondria in cardiomyocytes through mitophagy can restore mitochondrial homeostasis, reduce oxidative stress and improve diabetic cardiomyopathy. Therefore, this article provides a comprehensive review of the mechanisms and characteristics of mitochondrial autophagy in diabetic cardiomyopathy. It aims to offer new insights and theoretical basis for the prevention and treatment of diabetic cardiomyopathy.

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.

Shenfu Injection alleviates sepsis-associated lung injury by regulating HIF-1α / 中国中药杂志

Shenfu Injection(SFI) is praised for the high efficacy in the treatment of septic shock. However, the precise role of SFI in the treatment of sepsis-associated lung injury is not fully understood. This study investigated the protective effect of SFI on sepsis-associated lung injury by a clinical trial and an animal experiment focusing on the hypoxia-inducing factor-1α(HIF-1α)-mediated mitochondrial autophagy. For the clinical trial, 70 patients with sepsis-associated lung injury treated in the emergency intensive care unit of the First Affiliated Hospital of Zhengzhou University were included. The levels of interleukin(IL)-6 and tumor necrosis factor(TNF)-α were measured on days 1 and 5 for every patient. Real-time quantitative polymerase chain reaction(RT-qPCR) was performed to determine the mRNA level of hypoxia inducible factor-1α(HIF-1α) in the peripheral blood mononuclear cells(PBMCs). For the animal experiment, 32 SPF-grade male C57BL/6J mice(5-6 weeks old) were randomized into 4 groups: sham group(n=6), SFI+sham group(n=10), SFI+cecal ligation and puncture(CLP) group(n=10), and CLP group(n=6). The body weight, body temperature, wet/dry weight(W/D) ratio of the lung tissue, and the pathological injury score of the lung tissue were recorded for each mouse. RT-qPCR and Western blot were conducted to determine the expression of HIF-1α, mitochondrial DNA(mt-DNA), and autophagy-related proteins in the lung tissue. The results of the clinical trial revealed that the SFI group had lowered levels of inflammatory markers in the blood and alveolar lavage fluid and elevated level of HIF-1α in the PBMCs. The mice in the SFI group showed recovered body temperature and body weight. lowered TNF-α level in the serum, and decreased W/D ratio of the lung tissue. SFI reduced the inflammatory exudation and improved the alveolar integrity in the lung tissue. Moreover, SFI down-regulated the mtDNA expression and up-regulated the protein levels of mitochondrial transcription factor A(mt-TFA), cytochrome c oxidase Ⅳ(COXⅣ), HIF-1α, and autophagy-related proteins in the lung tissue of the model mice. The findings confirmed that SFI could promote mitophagy to improve mitochondrial function by regulating the expression of HIF-1α.

Effect and mechanism of Danggui Buxue Decoction-containing serum in mitigating H9c2 cell injury caused by exposure to intermittent low oxygen / 中国中药杂志

This study aims to explore the effect and mechanism of Danggui Buxue Decoction(DBD)-containing serum in alleviating the H9c2 cell injury caused by the exposure to intermittent low oxygen. H9c2 cells were assigned into five groups: control(CON) group, intermittent low oxygen(IH) group, intermittent low oxygen plus DBD-containing serum(IH+DBD) group, intermittent low oxygen plus the autophagy enhancer rapamycin(IH+RAPA) group, and intermittent low oxygen plus DBD-containing serum and the autophagy inhibitor 3-methyladenine(IH+DBD+3-MA) group. Monodansylcadaverine(MDC) staining was employed to detect the changes of autophagosomes. Cell counting kit-8(CCK-8) assay was employed to determine the activity of myocardial cells, and lactate dehydrogenase(LDH) and creatine kinase(CK) kits were used to measure the LDH and CK levels in the cell culture, which would reflect the degree of cell damage. TdT-mediated dUTP nick-end labeling(TUNEL) staining was used to detect the apoptosis of myocardial cells, and JC-1 fluorescence probe to detect the changes in mitochondrial membrane potential. Western blot was employed to determine the expression levels of the autophagy-related proteins microtubule-associated proteins light chain 3Ⅱ(LC3Ⅱ), microtubule-associated proteins light chain 3Ⅰ(LC3Ⅰ), P62, Parkin and apoptosis related proteins pro caspase-3, caspase-3, B-cell lymphoma-2(Bcl-2), Bcl-2-associated X(Bax). The results showed that compared with the CON group, the IH group showed decreased fluorescence intensity of MDC staining, decreased LC3Ⅱ/LC3Ⅰ ratio, down-regulated Parkin expression, and up-regulated expression of P62. In addition, the IH group showed decreased cell survival rate, increased content of LDH and CK in the culture medium, increased number of TUNEL positive cells, and decreased pro caspase-3/caspase-3 and Bcl-2/Bax ratios and mitochondrial membrane potential. Compared with the IH group, the IH+DBD and IH+RAPA groups showed increased fluorescence intensity of MDC staining, increased LC3Ⅱ/LC3Ⅰ ratio, up-regulated Parkin expression, and down-regulated P62 expression. In addition, the two groups showed increased cell survival rate, reduced content of LDH and CK in the culture medium, decreased number of TUNEL positive cells, and increased pro caspase-3/caspase-3 and Bcl-2/Bax ratios and mitochondrial membrane potential. The IH+DBD+3-MA and IH groups showed no significant differences in the above indicators. Compared with the IH+DBD group, the IH+DBD+3-MA group showed decreased fluorescence intensity of MDC staining, decreased LC3Ⅱ/LC3Ⅰ ratio, down-regulated Parkin expression, and up-regulated P62 expression. In addition, the group had decreased cell survival rate, increased content of LDH and CK in the culture medium, increased number of TUNEL positive cells, decreased pro caspase-3/caspase-3 and Bcl-2/Bax ratios, and declined mitochon-drial membrane potential. To sum up, DBD could promote the mitophagy, inhibit the apoptosis, and alleviated the injury of H9c2 cells exposed to low oxygen.

Effect of mitophagy related genes on the antioxidant properties of Saccharomyces cerevisiae / 生物工程学报

Mitophagy is a process whereby cells selectively remove mitochondria through the mechanism of autophagy, which plays an important role in maintaining cellular homeostasis. In order to explore the effect of mitophagy genes on the antioxidant activities of Saccharomyces cerevisiae, mutants with deletion or overexpression of mitophagy genes ATG8, ATG11 and ATG32 were constructed respectively. The results indicated that overexpression of ATG8 and ATG11 genes significantly reduced the intracellular reactive oxygen species (ROS) content upon H2O2 stress for 6 h, which were 61.23% and 46.35% of the initial state, respectively. Notable, overexpression of ATG8 and ATG11 genes significantly increased the mitochondrial membrane potential (MMP) and ATP content, which were helpful to improve the antioxidant activities of the strains. On the other hand, deletion of ATG8, ATG11 and ATG32 caused mitochondrial damage and significantly decreased cell vitality, and caused the imbalance of intracellular ROS. The intracellular ROS content significantly increased to 174.27%, 128.68%, 200.92% of the initial state, respectively, upon H2O2 stress for 6 h. The results showed that ATG8, ATG11 and ATG32 might be potential targets for regulating the antioxidant properties of yeast, providing a new clue for further research.

Isoliquiritigenin alleviates energy metabolism imbalance in type 2 diabetic mice / 药学学报

Isoliquiritigenin (ISL) is a flavonoid compound isolated from licorice. It possesses excellent antioxidant and anti-diabetic activities. This study aims to investigate the molecular mechanism underlying the alleviatory effect of ISL on energy metabolism imbalance caused by type 2 diabetes mellitus (T2DM). 8-week-old male C57BL/6J mice were used in in vivo experiments. The high-fat-high-glucose diet combined with intraperitoneal injection of streptozotocin was applied to establish T2DM animal model. All animal experiments were performed in accordance with the Institutional Guidelines of Laboratory Animal Administration issued by the Committee of Ethics at Beijing University of Chinese Medicine. HepG2 cells were used in in vitro experiments. Enzyme-linked immunosorbent assay (ELISA) and real-time quantitative polymerase chain reaction (RT-qPCR) were used to examine the protein and mRNA levels of mitochondrial function-related targets. The levels of reactive oxygen species (ROS) and mitochondrial membrane potential (MMP) in HepG2 cells were measured by the flow cytometry. Additionally, the molecular docking of ISL and key target proteins was analyzed. It was found that ISL significantly inhibited the activity of mitochondrial respiratory chain complex I and increased the protein levels of uncoupling protein 2 (UCP2) in the livers of mice and HepG2 cells. It also obviously decreased the ROS levels and increased the MMP levels in cultured HepG2 cells. In addition, ISL promoted mitochondrial biogenesis by activating proliferator-activated receptor gamma co-activator 1α (PGC-1α) and enhanced mitophagy by upregulating Parkin. It also improved mitochondrial fusion by increasing the mRNA and protein levels of mitofusin 2 (MFN2). In conclusion, ISL alleviates energy metabolism imbalance caused by T2DM through suppression of excessive mitochondrial oxidative phosphorylation and promotion of mitochondrial biogenesis, mitophagy, and fusion.

Role of PHB2 in mitochondrial calcium dynamics and mitophagy / 中国药理学与毒理学杂志

OBJECTIVE Mitochondria plays a crucial role in cellular homeostasis by regulating various pro-cesses,including calcium signaling and mitophagy.This study aimed to explore the involvement of prohibitin 2(PHB2),an inner mitochondrial membrane protein,in the modulation of mitochondrial calcium dynamics and mitoph-agy.METHODS HEK293T cells were used as the experi-mental cells and were divided into control,PHB2 knock-down,and PHB2 overexpression groups.To evaluate mitochondrial calcium dynamics,Rhod-2 AM and Mito-Tracker Green fluorescence dyesrhod-2 staining and laser confocal microscopy were employed to visualize mito-chondrial calcium imaging.Additionally,Green-5N was utilized to measure the rate of mitochondrial calcium uptake.The mitochondrial membrane potential was assessed using JC-10 staining and laser confocal micros-copy,while cellular ATP levels were determined using ATP assay kits.Furthermore,mitochondrial autophagy was induced by treatment with CCCP,and the expression lev-els of TOM20,LC3,and PARKIN,key mitophagy-related proteins,were analyzed using Western blotting.RESULTS The results demonstrated that compared to the control group,the overexpression of PHB2 increased mitochon-drial calcium concentration,mitochondrial calcium uptake rate,ATP level and expression levels of LC3 and PAR-KIN,but decreased mitochondrial membrane potential and TOM20 expression.In contrast,PHB2 knockdown reduced mitochondrial calcium concentration,ATP level and expression levels of LC3 and PARKIN,but elevated mitochondrial membrane potential,and TOM20 expres-sion.CONCLUSION This study provides evidence that PHB2 plays a vital role in regulating mitochondrial calci-um dynamics,which in turn influences mitochondrial func-tion and modulates mitochondrial autophagy.These find-ings contribute to our understanding of the molecular mechanisms underlying the interplay between PHB2,mitochondrial calcium signaling,and mitophagy.

Voltage Dependent Anion Channel 1 Mediated Inflammation and Obstructive Sleep Apnea Syndrome / 中山大学学报(医学科学版)

VDAC1（voltage dependent anion channel 1）is an important channel protein on the outer mitochondrial outer membrane， which regulates mitophagy， participates in the regulation of inflammatory cytokines and the activation of the inflammasome， hence being crucial to the inflammatory response. Patients with obstructive sleep apnea syndrome （OSAS） suffer neuroinflammation due to intermittent hypoxia and increased oxidative stress， leading to chronic damage and neuronal cell apoptosis， and eventually develop cognitive impairment. Since OSAS patients' cognitive impairment is significantly influenced by inflammation， and VDAC1 regulates the activation of the inflammasome， the relationship between OSAS and VDAC1， mitophagy， as well as inflammation are reviewed here. We hope that this study can provide a new breakthrough in mitophagy and inflammation in patients with cognitive dysfunction caused by OSAS.

Effects of Dianxianqing granules on tau protein in P301S mice by regulating mitophagy / 中国药房

OBJECTIVE To study the effects of Dianxianqing granules on the tau protein in P301S mice by regulating mitophagy. METHODS Totally 36 P301S mice were randomly divided into model group， Dianxianqing granule group （12.48 g/kg）， donepezil hydrochloride group （positive control， 1.3 mg/kg）， with 12 mice in each group； another 10 C57BL6 mice were selected as control group. Administration groups were given relevant drug solutions intragastrically， and control group and model group were given constant volume of water intragastrically. The gavage volume was 20 mL/kg， once a day， for consecutive 5 months. During the experiment， the general condition of mice was observed in each group. After the last medication， the learning and memory ability was determined by Y maze test and Morris water maze test； HE staining was used to observe the morphological changes in brain tissue， and Nissl staining was used to observe the structure of neural cells and the number of Nissl bodies in cerebral tissue. Immunohistochemistry was used to detect the expressions of phospho-tau serine 202/threonine 205 （abbreviated as AT8） in brain tissue. Western blot assay was used to determine the expressions of mitophagy-associated proteins [PTEN-induced putative kinase-1 （PINK1）， Parkin， microtubule-associated protein 1 light chain 3B （LC3B）， p62]， synaptic-associated proteins [postsynaptic density protein-95 （PSD-95）， synaptophysin （SYP）， and growth-associated protein-43 （GAP-43）] and the phosphorylation of tau protein [expressed by the phosphorylation levels of serine 199 （Ser199） and Ser202] in brain tissue. RESULTS The mice in E-mail：lnzyxyqy2003@163.com model group showed symptoms such as white hair， decreased body mass， and lower limb paralysis， with incomplete hippocampal structures in their brain tissue， as well as incomplete cell membrane edges and cell structures； the spontaneous alternating response rate， the times of crossing platform， the number of Nissl bodies， the protein expressions of PINK1， Parkin， LC3B， SYP， GAP-43， and PSD-95 were decreased significantly， compared with control group； swimming latency （fourth and fifth day）， the protein expressions of AT8 and p62，the phosphorylation levels of Ser199 and Ser202 were increased or lengthened significantly， compared with control group （P＜0.05 or P＜0.01）. Compared with model group， the above symptoms and indexes of mice were improved significantly in administration groups （P＜0.05 or P＜0.01）. CONCLUSIONS Dianxianqing granules can effectively improve cognitive impairment in P301S mice，the mechanism of which may be associated with inducing mitochondrial autophagy， reducing the hyperphosphorylation of tau protein， up-regulating the expression of synaptic-associated proteins in brain tissue，and repairing damaged neural cells.