Analysis of the autophagy gene expression profile of pancreatic cancer based on autophagy-related protein microtubule-associated protein 1A/1B-light chain 3

BACKGROUND Pancreatic cancer is a highly invasive malignant tumor. Expression levels of the autophagy-related protein microtubule-associated protein 1 A/1 B-light chain 3(LC3) and perineural invasion(PNI) are closely related to its occurrence and development. Our previous results showed that the high expression of LC3 was positively correlated with PNI in the patients with pancreatic cancer. In this study, we further searched for differential genes involved in autophagy of pancreatic cancer by gene expression profiling and analyzed their biological functions in pancreatic cancer, which provides a theoretical basis for elucidating the pathophysiological mechanism of autophagy in pancreatic cancer and PNI.AIM To identify differentially expressed genes involved in pancreatic cancer autophagy and explore the pathogenesis at the molecular level.METHODS Two sets of gene expression profiles of pancreatic cancer/normal tissue(GSE16515 and GSE15471) were collected from the Gene Expression Omnibus.Significance analysis of microarrays algorithm was used to screen differentially expressed genes related to pancreatic cancer. Gene Ontology(GO) analysis and Kyoto Encyclopedia of Genes and Genomes(KEGG) pathway analysis were used to analyze the functional enrichment of the differentially expressed genes. Protein interaction data containing only differentially expressed genes was downloaded from String database and screened. Module mining was carried out by Cytoscape software and ClusterOne plug-in. The interaction relationship between the modules was analyzed and the pivot nodes between the functional modules were determined according to the information of the functional modules and the data of reliable protein interaction network.RESULTS Based on the above two data sets of pancreatic tissue total gene expression, 6098 and 12928 differentially expressed genes were obtained by analysis of genes with higher phenotypic correlation. After extracting the intersection of the two differential gene sets, 4870 genes were determined. GO analysis showed that 14 significant functional items including negative regulation of protein ubiquitination were closely related to autophagy. A total of 986 differentially expressed genes were enriched in these functional items. After eliminating the autophagy related genes of human cancer cells which had been defined, 347 differentially expressed genes were obtained. KEGG pathway analysis showed that the pathways hsa04144 and hsa04020 were related to autophagy. In addition,65 clustering modules were screened after the protein interaction network was constructed based on String database, and module 32 contains the LC3 gene,which interacts with multiple autophagy-related genes. Moreover, ubiquitin C acts as a pivot node in functional modules to connect multiple modules related to pancreatic cancer and autophagy.CONCLUSION Three hundred and forty-seven genes associated with autophagy in human pancreatic cancer were concentrated, and a key gene ubiquitin C which is closely related to the occurrence of PNI was determined, suggesting that LC3 may influence the PNI and prognosis of pancreatic cancer through ubiquitin C.

GhWDL3 is involved in the formation and development of fiber cell morphology in upland cotton(Gossypium hirsutum L.)

Background Cotton fiber is a model tissue for studying microtubule-associated proteins(MAPs).The Xklp2(TPX2)proteins that belong to the novel MAPs member mainly participate in the formation and development of microtubule(MT).However,there is a lack of studies concerning the systematic characterization of the TPX2 genes family in cotton.Therefore,the identification and portrayal of G.hirsutum TPX2 genes can provide key targets for molecular manipula-tion in the breeding of cotton fiber improvement.Result In this study,TPX2 family genes were classified into two distinct subclasses TPXLs and MAP genes WAVE DAMP-ENED2-LIKE(WDLs)and quite conservative in quantity.GhWDL3 was significantly up-regulated in 15 days post anthe-sis fibers of ZRI-015(an upland cotton with longer and stronger fiber).GhWDL3 promotes all stem hairs to become straight when overexpressed in Arabidopsis,which may indirectly regulate cotton fiber cell morphology during fiber development.Virus induced gene silencing(VIGS)results showed that GhWDL3 inhibited fiber cell elongation at fiber development periods through regulating the expression of cell wall related genes.Conclusion These results reveal that GhWDL3 regulated cotton fiber cell elongation and provide crucial information for the further investigation in the regulatory mechanisms/networks of cotton fiber length.

Predictive and prognostic implications of 4E-BP1, Beclin-1, and LC3for cetuximab treatment combined with chemotherapy in advanced colorectal cancer with wild-type KRAS: Analysis from real-world data

BACKGROUND Colorectal cancer(CRC) is one of the main causes of cancer-related deaths in China and around the world. Advanced CRC(ACRC) patients suffer from a low cure rate though treated with targeted therapies. The response rate is about 50% to chemotherapy and cetuximab, a monoclonal antibody targeting epidermal growth factor receptor(EGFR) and used for ACRC with wild-type KRAS. It is important to identify more predictors of cetuximab efficacy to further improve precise treatment. Autophagy, showing a key role in the cancer progression, is influenced by the EGFR pathway. Whether autophagy can predict cetuximab efficacy in ACRC is an interesting topic.AIM To investigate the effect of autophagy on the efficacy of cetuximab in colon cancer cells and ACRC patients with wild-type KRAS.METHODS ACRC patients treated with cetuximab plus chemotherapy, with detailed data and tumor tissue, at Sun Yat-sen University Cancer Center from January 1, 2005,to October 1, 2015, were studied. Expression of autophagy-related proteins[Beclin1, microtubule-associated protein 1 A/B-light chain 3(LC3), and 4 Ebinding protein 1(4 E-BP1)] was examined by Western blot in CRC cells and by immunohistochemistry in cancerous and normal tissues. The effect of autophagy on cetuximab-treated cancer cells was confirmed by MTT assay. The associations between Beclin1, LC3, and 4 E-BP1 expression in tumor tissue and the efficacy of cetuximab-based therapy were analyzed.RESULTS In CACO-2 cells exposed to cetuximab, LC3 and 4 E-BP1 were upregulated, and P62 was downregulated. Autophagosome formation was observed, and autophagy increased the efficacy of cetuximab. In 68 ACRC patients,immunohistochemistry showed that Beclin1 levels were significantly correlated with those of LC3(0.657, P < 0.001) and 4 E-BP1(0.211, P = 0.042) in ACRC tissues.LC3 was significantly overexpressed in tumor tissues compared to normal tissues(P < 0.001). In 45 patients with wild-type KRAS, the expression levels of these three proteins were not related to progression-free survival; however, the expression levels of Beclin1(P = 0.010) and 4 E-BP1(P = 0.005), pathological grade(P = 0.002), and T stage(P = 0.004) were independent prognostic factors for overall survival(OS).CONCLUSION The effect of cetuximab on colon cancer cells might be improved by autophagy.LC3 is overexpressed in tumor tissues, and Beclin1 and 4 E-BP1 could be significant predictors of OS in ACRC patients treated with cetuximab.

Phosphorylation of tau protein over time in rats subjected to transient brain ischemia

Transient brain ischemia has been shown to induce hyperphosphorylation of the micro- tubule-associated protein tau. To further determine the mechanisms underlying these processes, we investigated the interaction between tau, glycogen synthase kinase （GSK）-313 and protein phos- phatase 2A. The results confirmed that tau protein was dephosphorylated during brain ischemia; in addition, the activity of GSK-3β was increased and the activity of protein phosphatase 2A was de- creased. After reperfusion, tau protein was hyperphosphorylated, the activity of GSK-3β was de- creased and the activity of protein phosphatase 2A remained low. Importantly, the interaction of tau with GSK-3β and protein phosphatase 2A was altered during ischemia and reperfusion. Lithium chloride could affect tau phosphorylation by regulating the interaction of tau with GSK-3β and pro- tein phosphatase 2A, and improve learning and memory ability of rats after transient brain ischemia. The present study demonstrated that it was the interaction of tau with GSK-3β and protein phos- phatase 2A, rather than their individual activities, that dominates the phosphorylation of tau in tran- sient brain ischemia. Hyperphosphorylated tau protein may play an important role in the evolution of brain injury in ischemic stroke. The neuroprotective effects of lithium chloride partly depend on the inhibition of tau phosphorylation during transient brain ischemia.

ROS-mediated BNIP3-dependent mitophagy promotes coelomocyte survival in Apostichopus japonicus in response to Vibrio splendidus infection

Organisms produce high levels of reactive oxygen species(ROS)to kill pathogens or act as signaling molecules to induce immune responses;however,excessive ROS can result in cell death.To maintain ROS balance and cell survival,mitophagy selectively eliminates damaged mitochondria via mitophagy receptors in vertebrates.In marine invertebrates,however,mitophagy and its functions remain largely unknown.In the current study,Vibrio splendidus infection damaged mitochondrial morphology in coelomocytes and reduced mitochondrial membrane potential(ΔΨm)and mitophagosome formation.The colocalization of mitochondria and lysosomes further confirmed that lipopolysaccharide(LPS)treatment increased mitophagy flux.To explore the regulatory mechanism of mitophagy,we cloned Bcl2/adenovirus E1 B 19 kDa protein-interacting protein 3(BNIP3),a common mitophagy receptor,from sea cucumber Apostichopus japonicus(Aj BNIP3)and confirmed that Aj BNIP3 was significantly induced and accumulated in mitochondria after V.splendidus infection and LPS exposure.At the mitochondrial membrane,Aj BNIP3 interacts with microtubule-associated protein 1 light chain 3(LC3)on phagophore membranes to mediate mitophagy.After Aj BNIP3 interference,mitophagy flux decreased significantly.Furthermore,Aj BNIP3-mediated mitophagy was activated by ROS following the addition of exogenous hydrogen peroxide(H2 O2),ROS scavengers,and ROS inhibitors.Finally,inhibition of BNIP3-mediated mitophagy by Aj BNIP3 small interfering RNA(si RNA)or high concentrations of lactate increased apoptosis and decreased coelomocyte survival.These findings highlight the essential role of Aj BNIP3 in damaged mitochondrial degradation during mitophagy.This mitophagy activity is required for coelomocyte survival in A.japonicus against V.splendidus infection.

自噬相关基因Atg12和LC3-Ⅱ在脑缺血再灌注大脑表达的实验研究

目的:探讨局灶性脑缺血再灌注损伤(cerebral ischemia reperfusion injury,CIR)时大脑皮质自噬相关蛋白-12(autophagy related protein-12,Atg12)和自噬微管相关蛋白轻链3抗体Ⅱ(autophagy microtubule-associated protein light chain 3 antibodyⅡ,LC3-Ⅱ)的激活规律,在此基础上探讨其对脑组织自噬的影响。方法:实验分为假手术组(sham组)和缺血再灌注组(CIR组),且CIR组下设CIR 0、6、12、24、48、72h共6个亚组。除sham组和CIR 24h组为每组20只外(其中10只用于模型鉴定),其余为每组10只。采用大脑中动脉栓塞术制备局灶性脑缺血再灌注模型,再灌注24 h后采用神经功能评分、2,3,5-三苯基氯化四氮唑(2,3,5-Triphenyltetrazolium chloride,TTC)染色、脑组织含水量来鉴定脑缺血模型是否成功。采用免疫组化和免疫印迹方法检测大脑皮质Atg12和LC3-Ⅱ的表达规律。结果:与sham组比较,CIR 24h组可见明显的神经功能缺损、脑梗死和明显的脑水肿。免疫组化结果显示,Atg12和LC3-Ⅱ在大鼠脑缺血再灌注6 h开始表达[阳性率分别为(15.49±4.18)%、(18.54±3.62)%],在24~48 h达高峰[(33.63±3.26)%、(29.62±1.73)%],72 h之后逐渐减弱[(24.90±3.96)%、(20.36±3.51)%]。免疫印迹结果显示,Atg12和LC3-Ⅱ在大鼠脑缺血再灌注6 h开始表达[表达量为(0.372 3±0.076 5)、(0.148 4±0.011 5)],在24~48 h达高峰[(0.741 7±0.071 8)、(0.451 3±0.019 0)],72 h之后逐渐减弱[(0.365 0±0.042 0)、(0.245 1±0.030 3)]。结论:脑缺血时Atg12和LC3-Ⅱ在调节脑缺血的脑组织自噬方式中具有重要的作用。

Association of CFH and MAP1LC3B gene polymorphisms with age-related macular degeneration in a high-altitude population

AIM: To evaluate the association of complement factor H(CFH) and microtubule-associated protein 1 light chain 3 beta(MAP1LC3B) gene polymorphisms with the risk of age-related macular degeneration(AMD) in a high-altitude population. METHODS: The study group consisted of 172 participants with symptoms of AMD who were examined and diagnosed between January 2019 and June 2020. The control group was composed of 120 healthy individuals. Each participant was required to provide two milliliters of peripheral blood for DNA extraction. Two single nucleotide polymorphisms(SNPs) of CFH(rs1061170 and rs800292) and two SNPs of MAP1LC3B(rs8044820 and rs9903) were genotyped. The genotypes and allele frequencies of the SNPs in the study and control groups were further compared using Chi-square and Fisher’s exact tests. RESULTS: In a high-altitude population, the nominally significant differences of rs800292 and rs9903’s genotype AG frequencies were observed in the AMD group(P=0.034 and 0.004, respectively). The frequencies of allele G of rs800292 and allele A of rs9903 were also significantly dif ferent in the AMD group compared to the control [(P=0.034, OR=0.70, 95%CI: 0.50-0.98) and(P=0.004, OR=1.60, 95%CI: 1.15-2.22), respectively]. No significant differences in the genotype distributions(P=0.16 and 0.40, respectively) and allele frequencies(P>0.05) of rs1061170 and rs8044820 were observed in the AMD group.CONCLUSION: Genotype AG of rs800292 may be a protective factor for AMD. Conversely, rs9903 seems to be a risk factor for AMD. Therefore, allele G of rs800292 may be a protective factor, and allele A of rs9903, a risk factor for AMD in Qinghai high-altitude population.

A novel mechanism of PHB2-mediated mitophagy participating in the development of Parkinson's disease

Endoplasmic reticulum stress and mitochondrial dysfunction play important roles in Parkinson s disease,but the regulato ry mechanism remains elusive.Prohibitin-2(PHB2)is a newly discove red autophagy receptor in the mitochondrial inner membrane,and its role in Parkinson’s disease remains unclear.Protein kinase R(PKR)-like endoplasmic reticulum kinase(PERK)is a factor that regulates cell fate during endoplasmic reticulum stress.Parkin is regulated by PERK and is a target of the unfolded protein response.It is unclear whether PERK regulates PHB2-mediated mitophagy thro ugh Parkin.In this study,we established a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine(MPTP)-induced mouse model of Parkinson’s disease.We used adeno-associated virus to knockdown PHB2 expression.Our res ults showed that loss of dopaminergic neurons and motor deficits were aggravated in the MPTP-induced mouse model of Parkinson’s disease.Ove rexpression of PHB2 inhibited these abnormalities.We also established a 1-methyl-4-phenylpyridine(MPP+)-induced SH-SY5Y cell model of Parkinson’s disease.We found that ove rexpression of Parkin increased co-localization of PHB2 and microtubule-associated protein 1 light chain 3,and promoted mitophagy.In addition,MPP+regulated Parkin involvement in PHB2-mediated mitophagy through phosphorylation of PERK.These findings suggest that PHB2 participates in the development of Parkinson’s disease by intera cting with endoplasmic reticulum stress and Parkin.

自噬在血管性痴呆发病中的作用研究

目的研究自噬在血管性痴呆(VD)发病中的作用及自噬抑制剂对其的影响。方法 180只SD大鼠随机分为假手术组、VD组和自噬抑制剂干预组(自噬抑制剂组),每组又分为术后1、2、4、8、12周亚组。采用四血管阻断法制作VD大鼠模型,自噬抑制剂组大鼠在术前1 h给予渥曼青霉素0.5 mg/kg腹腔注射。用Morris水迷宫试验检测大鼠的学习记忆能力;免疫组化SP法检测大鼠海马CA1区自噬相关蛋白Beclin-1、Cathepsin B的表达,Western-blotting法检测自噬活性微管相关蛋白1轻链3(LC3)Ⅱ与Ⅰ的比值。结果与假手术组比较,VD组和自噬抑制剂组各亚组大鼠的学习、记忆能力明显降低;海马CA1区Beclin-1、Cathepsin B蛋白表达水平及LC3Ⅱ/LC3Ⅰ比值明显升高(P<0.05～0.01),并均以术后第4周为最高。而自噬抑制剂组各亚组大鼠的学习、记忆能力明显好于,海马CA1区Beclin-1、Cathepsin B蛋白表达水平及LC3Ⅱ/LC3Ⅰ比值明显低于VD组(P<0.05～0.01)。结论 VD大鼠的认知功能减退,海马自噬相关蛋白表达及自噬活性明显增高;自噬抑制剂对其有改善及抑制的效果。自噬在VD发病中起了重要的作用。

脓毒症相关性脑病大鼠海马区神经细胞自噬

目的:探讨脓毒症相关性脑病(sepsis-associated encephalopathy,SAE)大鼠海马区神经细胞自噬现象及微管相关蛋白1轻链3(LC3)的表达。方法:盲肠结扎穿孔术(cecal ligation and puncture,CLP)建立脓毒症大鼠模型。60只30日龄健康雄性Wistar大鼠被随机分为假手术组(10只)和CLP组(50只)。CLP后12 h监测大鼠脑电图(electroencephalogram,EEG)及体感诱发电位(somatosensory evoked potential,SEP),并进行神经生物学评分。根据大鼠是否发生SAE将CLP组大鼠再分为SAE(+)组和SAE(–)组。HE染色观察大鼠海马区病理学改变;电子显微镜观察大鼠海马区神经细胞自噬的超微结构;Western印迹检测LC3-I和LC3-II蛋白的表达。结果:50只大鼠在CLP后12 h内死亡5只,存活45只大鼠中有16只出现神经行为学、EEG及SEP改变,诊断为SAE,其发病率为35.56%(16/45)。与假手术组和SAE(–)组比较,SAE(+)组大鼠在CLP后12 h时α波的频率明显减少,δ波增加,P1振幅下降,P1波和N1波潜伏期延长(P<0.05)。CLP后12 h时SAE(+)组大鼠海马区细胞明显水肿,锥体细胞明显减少,甚至溶解,细胞排列紊乱,而假手术组和SAE(–)组大鼠海马区细胞形态正常、层次清楚。透射电子显微镜观察表明:SAE(+)组大鼠海马区细胞结构紊乱,可见自噬泡、颗粒状基质和方形或长方形晶体,自噬泡内含有溶酶体等细胞器,假手术组和SAE(–)组大鼠海马区组织细胞无自噬泡形成。SAE(+)组大鼠在CLP后12 h,海马区神经细胞LC3-II/LC3-I值明显高于假手术组和SAE(–)组(P<0.05)。结论:SAE大鼠海马区神经细胞存在细胞自噬现象,LC3-II/LC3-I值明显升高。

大鼠肾脏缺血再灌注损伤后自噬的初步研究

目的研究大鼠肾脏缺血再灌注(I/R)损伤后自噬溶酶体相关蛋白随损伤时间表达的规律,检测自噬体、溶酶体的变化。方法采用肾动脉夹闭法制作大鼠肾脏I/R损伤模型,将实验动物随机分入I/R组和对照组,每组在各时间点各6只。分别于I/R后2、6、12和24h,采用Western印迹法检测肾组织中自噬相关蛋白Belinl和微管相关蛋白1轻链3(LC)的表达情况,在透射电子显微镜下观察I/R后肾组织内自噬小体的形成情况。结果 I/R组大鼠肾组织内Beclin1和LC3蛋白表达水平均自I/R后2h起开始升高,至I/R后24h达到高峰(P值均<0.05)。透射电子显微镜下见,对照组大鼠近端小管上皮细胞核膜完整,染色质结构正常,细胞质中细胞器形态正常,未见自噬小体;I/R组大鼠I/R后2h可见到损伤区域有自噬体形成,溶酶体增多,I/R后24h最为明显。结论大鼠肾I/R损伤后肾组织的自噬活性升高。

Optimal concentration and time window for proliferation and differentiation of neural stem cells from embryonic cerebral cortex: 5% oxygen preconditioning for 72 hours

Hypoxia promotes proliferation and differentiation of neural stem cells from embryonic day 12 rat brain tissue, but the concentration and time of hypoxic preconditioning are controversial. To address this, we cultured neural stem cells isolated from embryonic day 14 rat cerebral cortex in 5% and 10% oxygen in vitro. MTT assay, neurosphere number, and immunofluorescent staining found that 5% or 10% oxygen preconditioning for 72 hours improved neural stem cell viability and proliferation. With prolonged hypoxic duration （120 hours）, the proportion of apoptotic cells increased. Thus, 5% oxygen preconditioning for 72 hours promotes neural stem cell prolif- eration and neuronal differentiation. Our findings indicate that the optimal concentration and duration of hypoxic preconditioning for promoting proliferation and differentiation of neural stem cells from the cerebral cortex are 5% oxygen for 72 hours.

m TOR signaling in liver regeneration: Rapamycin combined with growth factor treatment

AIM: To investigate the effects of mammalian target of rapamycin(mT OR) inhibition on liver regeneration and autophagy in a surgical resection model.METHODS: C57BL/6 mice were subjected to a 70% partial hepatectomy(PH) and treated intraperitoneally every 24 h with a combination of the m TOR inhibitor rapamycin(2.5 mg/kg per day) and the steroid dexamethasone(2.0 mg/kg per day) in phosphate bufferedsaline(PBS) or with PBS alone as vehicle control. In the immunosuppressant group, part of the group was treated subcutaneously 4 h prior to and 24 h after PH with a combination of human recombinant interleukin 6(IL-6; 500 μg/kg per day) and hepatocyte growth factor(HGF; 100 μg/kg per day) in PBS. Animals were sacrificed 2, 3 or 5 d after PH and liver tissue and blood were collected for further analysis. Immunohistochemical staining for 5-Bromo-2'-deoxyuridine(Brd U) was used to quantify hepatocyte proliferation. Western blotting was used to detect hepatic microtubule-associated protein 1 light chain 3(LC3)-Ⅱ protein expression as a marker for autophagy. Hepatic gene expression levels of proliferation-, inflammation- and angiogenesisrelated genes were examined by real-time reverse transcription-polymerase chain reaction and serum bilirubin and transaminase levels were analyzed at the clinical chemical core facility of the Erasmus MC-University Medical Center.RESULTS: m TOR inhibition significantly suppressed regeneration, shown by decreased hepatocyte proliferation(2% vs 12% Brd U positive hepatocyte nuclei at day 2, P < 0.01; 0.8% vs 1.4% at day 5, P = 0.02) and liver weight reconstitution(63% vs 76% of initial total liver weight at day 3, P = 0.04), and furthermore increased serum transaminase levels(aspartate aminotransferase 641 U/L vs 185 U/L at day 2, P = 0.02). Expression of the autophagy marker LC3-Ⅱ, which was reduced during normal liver regeneration, increased after mT OR inhibition(46% increase at day 2, P = 0.04). Hepatic gene expression showed an increased inflammation-related response [tumor necrosis factor(TNF)-α 3.2-fold upregulation at day 2, P = 0.03; IL-1Ra 6.0-fold upregulation at day 2 and 42.3-fold upregulation at day 5, P < 0.01] and a reduced expression of cell cycle progression and angiogenesis-related factors(HGF 40% reduction at day 2; vascular endothelial growth factor receptor 2 50% reduction at days 2 and 5; angiopoietin 1 60% reduction at day 2, all P ≤ 0.01). Treatmentwith the regeneration stimulating cytokine IL-6 and growth factor HGF could overcome the inhibitory effect on liver weight(75% of initial total liver weight at day 3, P = 0.02 vs immunosuppression alone and P = 0.90 vs controls) and partially reversed gene expression changes caused by rapamycin(TNF-α and IL-1Ra levels at day 2 were restored to control levels). However, no significant changes in hepatocyte proliferation, serum injury markers or autophagy were found.CONCLUSION: mT OR inhibition severely impairs liver regeneration and increases autophagy after PH. These effects are partly reversed by stimulation of the IL-6 and HGF pathways.

Micro RNA-9 promotes the neuronal differentiation of rat bone marrow mesenchymal stem cells by activating autophagy

MicroRNA-9 （miR-9） has been shown to promote the differentiation of bone marrow mesen-chymal stem cells into neuronal cells, but the precise mechanism is unclear. Our previous study conifrmed that increased autophagic activity improved the efifciency of neuronal differentiation in bone marrow mesenchymal stem cells. Accumulating evidence reveals that miRNAs adjust the autophagic pathways. This study used miR-9-1 lentiviral vector and miR-9-1 inhibitor to modulate the expression level of miR-9. Autophagic activity and neuronal differentiation were measured by the number of light chain-3 （LC3）-positive dots, the ratio of LC3-II/LC3, and the expression levels of the neuronal markers enolase and microtubule-associated protein 2. Re-sults showed that LC3-positive dots, the ratio of LC3-II/LC3, and expression of neuron speciifc enolase and microtubule-associated protein 2 increased in the miR-9＋ group. The above results suggest that autophagic activity increased and bone marrow mesenchymal stem cells were prone to differentiate into neuronal cells when miR-9 was overexpressed, demonstrating that miR-9 can promote neuronal differentiation by increasing autophagic activity.

Choline dehydrogenase interacts with SQSTM1 to activate mitophagy and promote coelomocyte survival in Apostichopus japonicus following Vibrio splendidus infection

Previous studies have shown that Vibrio splendidus infection causes mitochondrial damage in Apostichopus japonicus coelomocytes,leading to the production of excessive reactive oxygen species(ROS)and irreversible apoptotic cell death.Emerging evidence suggests that mitochondrial autophagy(mitophagy)is the most effective method for eliminating damaged mitochondria and ROS,with choline dehydrogenase(CHDH)identified as a novel mitophagy receptor that can recognize non-ubiquitin damage signals and microtubule-associated protein 1 light chain 3(LC3)in vertebrates.However,the functional role of CHDH in invertebrates is largely unknown.In this study,we observed a significant increase in the mRNA and protein expression levels of A.japonicus CHDH(AjCHDH)in response to V.splendidus infection and lipopolysaccharide(LPS)challenge,consistent with changes in mitophagy under the same conditions.Notably,AjCHDH was localized to the mitochondria rather than the cytosol following V.splendidus infection.Moreover,AjCHDH knockdown using si RNA transfection significantly reduced mitophagy levels,as observed through transmission electron microscopy and confocal microscopy.Further investigation into the molecular mechanisms underlying CHDH-regulated mitophagy showed that AjCHDH lacked an LC3-interacting region(LIR)for direct binding to LC3 but possessed a FB1 structural domain that binds to SQSTM1.The interaction between AjCHDH and SQSTM1 was further confirmed by immunoprecipitation analysis.Furthermore,laser confocal microscopy indicated that SQSTM1 and LC3 were recruited by AjCHDH in coelomocytes and HEK293T cells.In contrast,AjCHDH interference hindered SQSTM1 and LC3 recruitment to the mitochondria,a critical step in damaged mitochondrial degradation.Thus,AjCHDH interference led to a significant increase in both mitochondrial and intracellular ROS,followed by increased apoptosis and decreased coelomocyte survival.Collectively,these findings indicate that AjCHDH-mediated mitophagy plays a crucial role in coelomocyte survival in A.japonicus following V.splendidus infection.

Mutant alpha-synuclein and autophagy in PC12 cells

Several studies have demonstrated that overexpression of mutant a-synuclein in PC12 cells is related to occurrence of autophagy. The present study established mutant α-synuclein （A30P） -transfected PC12 cells and treated them with the autophagy inducer rapamycin and autophagy inhibitor wortmannin, respectively. Results demonstrated that mutant a-synuclein resulted in cell death via autophagy and involved a-synuclein accumulation, membrane lipid oxidation, and loss of plasma membrane integrity. Mutant a-synuclein （A30P） also mediated toxicity of 1-methyl-4-phenylpyridinium ion. Moreover, rapamycin inhibited a-synuclein aggregation, while wortmannin promoted α-synuclein aggregation and cell death. To further determine the role of autophagy due to mutant α-synuclein, the present study measured expression of microtubule-associated protein light chain 3. Results revealed that wortmannin and 1-methyl-4-phenylpyridinium ion inhibited expression of microtubule-associated protein light chain 3 while rapamycin promoted its expression. These findings suggested that abnormal aggregation of a-synuclein induced autophagic programmed cell death in PC12 cells.

柯萨奇病毒B组3型2B蛋白诱导细胞自噬及其基序鉴定

目的 探讨柯萨奇病毒B组3型（CVB3） woodruff病毒2B蛋白对细胞自噬的诱导作用,及其自噬相关基序的鉴定.方法 分别构建增强型绿色荧光蛋白（EGFP）与CVB3 woodruff病毒2B蛋白及其9种截短蛋白的融合蛋白（EGFP-2B、EGFP-2B1-249、EGFP-2B1-201、EGFP-2B1-153、EGFP-2B1-105、EGFP-2B1-57、EGFP-2B106.201、EGFP-2B106-249、EGFP-2 B205-297、EGFP-2B106-201）真核表达载体,红色荧光蛋白（mCherry）与微管相关蛋白轻链3（LC3）的融合蛋白真核表达载体pmCherry-LC3;应用激光共聚焦与蛋白质免疫印迹（Western blot）检测病毒2B蛋白对宫颈癌细胞（HeLa） LC3表达的影响;荧光显微镜观察9种截短蛋白在HeLa细胞中的表达;Western blot检测pEGFP-2B和pEGFP-2B106-249转染细胞后LC3的表达;观察自噬抑制剂3-甲基腺苷（3-MA）处理后,pEGFP-2B和pEGFP-2B106-249诱导细胞自噬的情况.结果 CVB3攻击HeLa细胞后,mCherry-LC3呈现细胞核周点状聚集表达,Western blot检测出现清晰LC3-Ⅱ条带;pEGFP-2B与pmCherry-LC3共转染后也可见细胞核周围绿色荧光与红色荧光均成点状聚集并相互重叠,且LC3-Ⅱ条带明显;9种截短融合蛋白质粒分别转染HeLa细胞后,其中可见细胞核周围绿色荧光点状聚集的最短截短蛋白为EGFP-2B106-249;pEGFP-2B和pEGFP-2B106-249转染细胞后可检测出现清晰LC3-Ⅱ条带;3-MA处理后,pEGFP-2B和pEGFP-2B106-249分别与pmCherry-LC3共转染的细胞均未见绿色和红色荧光的核周点状聚集.结论 CVB3 woodruff病毒2B蛋白可以诱导宿主细胞发生自噬,其中截短蛋白2B106-249是病毒蛋白2B诱导HeLa细胞发生自噬的功能基序.

Structural insights of phosphorylated into the recognition FUNDC1 by LC3B in mitophagy

Mitophagy is an essential intracellular process that eliminates dysfunctional mitochondria and maintains cellular homeostasis. Mitophagy is regulated by the post-translational modification of mitophagy receptors. Fun14 domain-containing protein 1 （FUNDC1） was reported to be a new receptor for hypoxia-induced mitophagy in mammalian cells and interact with micro-tubule-associated protein light chain 3 beta （LC3B） through its LC3 interaction region （LIR）. Moreover, the phosphorylation modification of FUNDC1 affects its binding affinity for LC3B and regulates selective mitophagy. However, the structural basis of this regulation mechanism remains unclear. Here, we present the crystal structure of LC3B in complex with a FUNDCI LIR peptide phosphorylated at Ser17 （pS17）, demonstrating the key residues of LC3B for the specific recognition of the phosphorylated or dephosphorylated FUNDC1. Intriguingly, the side chain of LC3B Lys49 shifts remarkably and forms a hydrogen bond and electrostatic interaction with the phosphate group of FUNDC1 pS17. Alternatively, phosphorylated Tyr18 （PY18） and Ser13 （PS13） in FUNDC1 significantly obstruct their interaction with the hydrophobic pocket and Arg10 of LC3B, respectively. Structural observations are further validated by mutation and isothermal titration calorimetry （ITC） assays. Therefore, our structural and biochemical results reveal a working model for thespecific recognition of FUNDCI by LC3B and imply that the reversible phosphorylation modification of mitophagy receptors may be a switch for selective mitophagy.

肠道病毒71型诱导人恶性胶质瘤细胞U251自噬的研究

目的初步研究肠道病毒71型（EV71）诱导人恶性胶质瘤细胞U251的自噬现象及其对微管相关蛋白1轻链3（LC3）表达的影响。方法RPMI1640培养U251细胞24h后随机分为实验组和对照组，实验组按感染复数（MOI）值为1加入EV71，EV71感染12h后采用单丹磺酰戊二胺（MDC）染色标志细胞自噬泡，荧光显微镜观察自噬泡的形成。EV71感染24h后细胞免疫荧光检测LC3，荧光显微镜观察LC3在U251细胞内的分布。EV71感染2、4、8、12、24、48h采用Westernblot检On．0LC3-I和LC3-II蛋白的表达，并对LC3-II蛋白进行半定量分析。结果白噬泡经过MDC染色后，荧光显微镜观察发现自噬泡呈点状结构。与对照组比较，实验组在EV71感染12h，U251细胞内自噬泡明显增多；EV71感染24h，U251细胞皱缩、变小、形态不规则，LC3蛋白表达明显增多，主要分布在细胞质和细胞核周围；EV71感染4h后，LC3-II蛋白表达开始增加，明显高于对照组（P〈0．01）。结论EV71能有效诱导U251细胞自噬，发挥其溶瘤作用。

Regulation of autophagy:a promising therapeutic target for the treatment of hearing loss

Autophagy,a ubiquitous cellular biological behavior that features a lysosome-dependent degradation pathway,is an important mechanism for cellular self-protection in eukaryotes.Autophagy plays essential roles in cell survival,renewal,material reuse and the maintenance of homeostasis.This paper reviews recent advances in understanding the physiological function of autophagy and its possible roles in auditory diseases.We focused our review on original publications on animal models,drug models,and molecular mechanisms of hearing impairment involved in the dysregulation of autophagy.As research on the mechanisms of autophagy has deepened,it has become obvious that autophagy plays essential roles not only in cell survival,but the occurrence and development of a variety of auditory-related disorder,including aminoglycoside-induced hearing loss,age-related hearing loss,and noise-induced hearing loss.While clinical treatment of such conditions via regulation of the development of autophagy is a novel idea,more time is needed to fully elucidate the specific regulatory pathways and modes of autophagy in auditory diseases.The continued study of the mechanisms and regulation of autophagy in auditory diseases will be of great significance for the future treatment and prevention of these conditions.