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The ribosome-associated protein quality control (RQC) pathway acts as a translational surveillance mechanism to maintain proteostasis. In mammalian cells, the cytoplasmic RQC pathway involves nuclear export mediator factor (NEMF)-dependent recruitment of the E3 ligase Listerin to ubiquitinate ribosome-stalled nascent polypeptides on the lysine residue for degradation. However, the quality control of ribosome-stalled nuclear-encoded mitochondrial nascent polypeptides remains elusive, as these peptides can be partially imported into mitochondria through translocons, restricting accessibility to the lysine by Listerin. Here, we identify a Listerin-independent organelle-specific mitochondrial RQC pathway that acts on NEMF-mediated carboxy-terminal poly-alanine modification. In the pathway, mitochondrial proteins carrying C-end poly-Ala tails are recognized by the cytosolic E3 ligase Pirh2 and the ClpXP protease in the mitochondria, which coordinately clear ribosome-stalled mitochondrial nascent polypeptides. Defects in this elimination pathway result in NEMF-mediated aggregates and mitochondrial integrity failure, thus providing a potential molecular mechanism of the RQC pathway in mitochondrial-associated human diseases.
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Peptídeo Hidrolases , Ubiquitina-Proteína Ligases , Animais , Humanos , Ubiquitina-Proteína Ligases/metabolismo , Peptídeo Hidrolases/metabolismo , Biossíntese de Proteínas , Lisina/metabolismo , Peptídeos/metabolismo , Endopeptidases/metabolismo , Mitocôndrias/metabolismo , Ubiquitinação , Mamíferos/metabolismoRESUMO
BACKGROUND AND PURPOSE: The role of GGC repeat expansions within NOTCH2NLC in Parkinson's disease (PD) and the substantia nigra (SN) dopaminergic neuron remains unclear. Here, we profile the NOTCH2NLC GGC repeat expansions in a large cohort of patients with PD. We also investigate the role of GGC repeat expansions within NOTCH2NLC in the dopaminergic neurodegeneration of SN. METHODS: A total of 2,522 patients diagnosed with PD and 1,085 health controls were analyzed for the repeat expansions of NOTCH2NLC by repeat-primed PCR and GC-rich PCR assay. Furthermore, the effects of GGC repeat expansions in NOTCH2NLC on dopaminergic neurons were investigated by using recombinant adeno-associated virus (AAV)-mediated overexpression of NOTCH2NLC with 98 GGC repeats in the SN of mice by stereotactic injection. RESULTS: Four PD pedigrees (4/333, 1.2%) and three sporadic PD patients (3/2189, 0.14%) were identified with pathogenic GGC repeat expansions (larger than 60 GGC repeats) in the NOTCH2NLC gene, while eight PD patients and one healthy control were identified with intermediate GGC repeat expansions ranging from 41 to 60 repeats. No significant difference was observed in the distribution of intermediate NOTCH2NLC GGC repeat expansions between PD cases and controls (Fisher's exact test p-value = 0.29). Skin biopsy showed P62-positive intranuclear NOTCH2NLC-polyGlycine (polyG) inclusions in the skin nerve fibers of patient. Expanded GGC repeats in NOTCH2NLC produced widespread intranuclear and perinuclear polyG inclusions, which led to a severe loss of dopaminergic neurons in the SN. Consistently, polyG inclusions were presented in the SN of EIIa-NOTCH2NLC-(GGC)98 transgenic mice and also led to dopaminergic neuron loss in the SN. CONCLUSIONS: Overall, our findings provide strong evidence that GGC repeat expansions within NOTCH2NLC contribute to the pathogenesis of PD and cause degeneration of nigral dopaminergic neurons.
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Doença de Parkinson , Animais , Humanos , Camundongos , Neurônios Dopaminérgicos/patologia , Corpos de Inclusão Intranuclear/genética , Corpos de Inclusão Intranuclear/patologia , Camundongos Transgênicos , Degeneração Neural/patologia , Doença de Parkinson/genética , Doença de Parkinson/patologia , Substância Negra/patologia , Expansão das Repetições de TrinucleotídeosRESUMO
Maintaining mitochondrial homeostasis is a potential therapeutic strategy for various diseases, including neurodegenerative diseases, cardiovascular diseases, metabolic disorders, and cancer. Selective degradation of mitochondria by autophagy (mitophagy) is a fundamental mitochondrial quality control mechanism conserved from yeast to humans. Indeed, small-molecule modulators of mitophagy are valuable pharmaceutical tools that can be used to dissect complex biological processes and turn them into potential drugs. In the past few years, pharmacological regulation of mitophagy has shown promising therapeutic efficacy in various disease models. However, with the increasing number of chemical mitophagy modulator studies, frequent methodological flaws can be observed, leading some studies to draw unreliable or misleading conclusions. This review attempts (a) to summarize the molecular mechanisms of mitophagy; (b) to propose a Mitophagy Modulator Characterization System (MMCS); (c) to perform a comprehensive analysis of methods used to characterize mitophagy modulators, covering publications over the past 20 years; (d) to provide novel targets for pharmacological intervention of mitophagy. We believe this review will provide a panorama of current research on chemical mitophagy modulators and promote the development of safe and robust mitophagy modulators with therapeutic potential by introducing high methodological standards.
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Doenças Cardiovasculares , Neoplasias , Humanos , Mitofagia , Autofagia , Mitocôndrias/metabolismo , Doenças Cardiovasculares/tratamento farmacológico , Doenças Cardiovasculares/metabolismo , Neoplasias/tratamento farmacológico , Neoplasias/metabolismoRESUMO
The endosomal system maintains cellular homeostasis by coordinating multiple vesicular trafficking events, and the retromer complex plays a critical role in endosomal cargo recognition and sorting. Here, we demonstrate an essential role for the small GTPase RAB21 in regulating retromer-mediated recycling of the glucose transporter SLC2A1/GLUT1 and macroautophagy/autophagy. RAB21 depletion mis-sorts SLC2A1 to lysosomes and affects glucose uptake, thereby activating the AMPK-ULK1 pathway to increase autophagic flux. RAB21 depletion also increases lysosome function. Notably, RAB21 depletion does not overtly affect retrograde transport of IGF2R/CI-M6PR or WLS from endosomes to the trans-Golgi network. We speculate that RAB21 regulates fission of retromer-decorated endosomal tubules, as RAB21 depletion causes accumulation of the SNX27-containing retromer complex on enlarged endosomes at the perinuclear region. Functionally, RAB21 depletion sensitizes cancer cells to energy stress and inhibits tumor growth in vivo, suggesting an oncogenic role for RAB21. Overall, our study illuminates the role of RAB21 in regulating endosomal dynamics and maintaining cellular energy homeostasis and suggests RAB21 as a potential metabolic target for cancer therapy.
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Autofagia , Proteínas de Transporte Vesicular , Proteínas de Transporte Vesicular/metabolismo , Transportador de Glucose Tipo 1/metabolismo , Transporte Proteico/fisiologia , Endossomos/metabolismo , HomeostaseRESUMO
Parkinson's disease (PD) is a neurodegenerative disease caused by aging, environmental and genetic factors, and many susceptibility genes have been found to increase the risk for PD. Lin28a, an RNA binding protein, is expressed prominently in neural progenitor cells. The expression of Lin28a is decreased gradually with neural differentiation and is implicated in oncogenesis, glucose metabolism, neurogenesis, and neurogliogenesis. However, few genetic studies have explored the association between rare variants of the LIN28A gene and PD yet. Our study recruited 3,879 PD patients and 2,931 controls, and they were divided into two cohorts, including the EOPD & FPD cohort and the LOPD cohort, separately sequenced by whole-exome sequencing and whole-genome sequencing. We found nine rare nonsynonymous variants in the coding region of the LIN28A gene, but the rare variants of this gene were not enriched in PD patients in both cohorts. Thence, our study did not support the association between the LIN28A gene and the PD risk in the Chinese mainland population.
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Doença de Parkinson , Idade de Início , Povo Asiático , China , Predisposição Genética para Doença , Humanos , Doença de Parkinson/genética , Proteínas de Ligação a RNA/genéticaRESUMO
Transcriptional factor EB (TFEB), a master regulator of autophagy and lysosomal biogenesis, is generally regarded as a pro-survival factor. Here, we identify that besides its effect on autophagy induction, TFEB exerts a pro-apoptotic effect in response to the cyclopentenone prostaglandin 15-deoxy-∆-12,14-prostaglandin J2 (15d-PGJ2). Specifically, 15d-PGJ2 promotes TFEB translocation from the cytoplasm into the nucleus to induce autophagy and lysosome biogenesis via reactive oxygen species (ROS) production rather than mTORC1 inactivation. Surprisingly, TFEB promotes rather than inhibits apoptosis in response to 15d-PGJ2. Mechanistically, ROS-mediated TFEB translocation into the nucleus transcriptionally upregulates the expression of ATF4, which is required for apoptosis elicited by 15d-PGJ2. Additionally, inhibition of TFEB activation by ROS scavenger N-acetyl cysteine or inhibition of protein synthesis by cycloheximide effectively compromises ATF4 upregulation and apoptosis in response to 15d-PGJ2. Collectively, these results indicate that ROS-induced TFEB activation exerts a novel role in promoting apoptosis besides its role in regulating autophagy in response to 15d-PGJ2. This work not only evidences how TFEB is activated by 15d-PGJ2, but also unveils a previously unexplored role of ROS-dependent activation of TFEB in modulating cell apoptosis in response to 15d-PGJ2.
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Prostaglandina D2 , Prostaglandinas , Apoptose , Autofagia , Ciclopentanos , Prostaglandina D2/análogos & derivados , Prostaglandina D2/farmacologia , Prostaglandinas/farmacologia , Espécies Reativas de Oxigênio/metabolismoRESUMO
ABBREVIATIONS: Aß: ß-amyloid; AD: Alzheimer disease; AIF1/IBA1: allograft inflammatory factor 1; ALP: autophagy-lysosomal pathway; APP: amyloid beta precursor protein; ATP6V1B1/V-ATPase V1b1: ATPase H+ transporting V1 subunit B1; AVs: autophagy vacuoles; BAF: bafilomycin A1; CFC: contextual/cued fear conditioning assay; CHX: Ca2+/H+ exchanger; CTF-ß: carboxy-terminal fragment derived from ß-secretase; CTSD: cathepsin D; fAD: familial Alzheimer disease; GFAP: glial fibrillary acidic protein; LAMP1: lysosomal associated membrane protein 1; LTP: long-term potentiation; MCOLN1/TRPML1: mucolipin 1; MAP1LC3B/LC3B: microtubule associated protein 1 light chain 3 beta; MAPT: microtubule associated protein tau; MWM: Morris water maze; NFT: neurofibrillary tangles; PFC: prefrontal cortex; PSEN1: presenilin 1; SQSTM1/p62: sequestosome 1; TBS: theta burst stimulation; TEM: transmission electronic microscopy; TPCN2/TPC2: two pore segment channel 2; WT: wild-type; V-ATPase: vacuolar type H+-ATPase.
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Doença de Alzheimer , ATPases Vacuolares Próton-Translocadoras , Adenosina Trifosfatases/metabolismo , Doença de Alzheimer/patologia , Peptídeos beta-Amiloides/metabolismo , Autofagia/fisiologia , Humanos , Lisossomos/metabolismo , Transtornos da Memória/metabolismo , ATPases Vacuolares Próton-Translocadoras/metabolismoRESUMO
PM2.5, also known as fine particles, refers to particulate matter with a dynamic diameter of â¦2.5 µm in air pollutants, that carries metals (Zn, Co, Cd) which can pass through the alveolar epithelium and enter the circulatory system and tissues. PM2.5 can cause serious health problems, such as non-alcoholic fatty liver and hepatocellular carcinoma, although the underlying mechanisms of its toxic effect are poorly understood. Here, we exposed L02 cells to PM2.5 and performed a pooled genome-wide clustered regularly interspaced short palindromic repeats/CRISPR-associated protein 9 (CRISPR/Cas9) to assess loss of function and identify new potential PM2.5targets. Enrichr and KEGG pathway analyses were performed to identify candidate genes associated with PM2.5 toxicity. Results revealed that four key genes, namely ATPase Na+/K+ transporting subunit alpha 2 (ATP1A2), metallothionein 1M (MT1M), solute carrier family 6 members 19 (SLC6A19) and transient receptor potential cation channel subfamily V member 6 (TRPV6) were associated with PM2.5 toxicity, mainly in regulating the mineral absorption pathway. Downregulating these genes increased cell viability and attenuated apoptosis in cells exposed to PM2.5. Conversely, overexpressing TRPV6 exacerbated cell apoptosis caused by PM2.5, while a reactive oxygen species (ROS) inhibitor N-acetyl-l-cysteine (NAC) alleviated PM2.5-induced apoptosis. In conclusion, ATP1A2, MT1M, SLC6A19 and TRPV6 may be contributing to absorption of metals in PM2.5 thereby inducing apoptosis mediated by ROS. Therefore, they hold potential as therapeutic targets for PM2.5-related diseases.
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BACKGROUND: Parkinson's disease (PD) is one of the most common neurodegenerative motor disorders, and is characterized by the presence of Lewy bodies containing misfolded α-synuclein (α-syn) and by selective degeneration of midbrain dopamine neurons. Studies have shown that upregulation of ubiquitin-proteasome system (UPS) activity promotes the clearance of aggregation-prone proteins such as α-syn and Tau, so as to alleviate the neuropathology of neurodegenerative diseases. PURPOSE: To identify and investigate lycorine as a UPS enhancer able to decrease α-syn in transgenic PD models. METHODS: Dot blot was used to screen α-syn-lowering compounds in an inducible α-syn overexpression cell model. Inducible wild-type (WT) and mutant α-syn-overexpressing PC12 cells, WT α-syn-overexpressing N2a cells and primary cultured neurons from A53T transgenic mice were used to evaluate the effects of lycorine on α-syn degradation in vitro. Heterozygous A53T transgenic mice were used to evaluate the effects of lycorine on α-syn degradation in vivo. mCherry-GFP-LC3 reporter was used to detect autophagy-dependent degradation. Ub-R-GFP and Ub-G76V-GFP reporters were used to detect UPS-dependent degradation. Proteasome activity was detected by fluorogenic substrate Suc-Leu-Leu-Val-Tyr-AMC (Suc-LLVY-AMC). RESULTS: Lycorine significantly promoted clearance of over-expressed WT and mutant α-syn in neuronal cell lines and primary cultured neurons. More importantly, 15 days' intraperitoneal administration of lycorine effectively promoted the degradation of α-syn in the brains of A53T transgenic mice. Mechanistically, lycorine accelerated α-syn degradation by activating cAMP-dependent protein kinase (PKA) to promote proteasome activity. CONCLUSION: Lycorine is a novel α-syn-lowering compound that works through PKA-mediated UPS activation. This ability to lower α-syn implies that lycorine has the potential to be developed as a pharmaceutical for the treatment of neurodegenerative diseases, such as PD, associated with UPS impairment and protein aggregations.
Assuntos
Alcaloides de Amaryllidaceae/farmacologia , Proteínas Quinases Dependentes de AMP Cíclico/metabolismo , Doença de Parkinson/tratamento farmacológico , Fenantridinas/farmacologia , alfa-Sinucleína/metabolismo , Animais , Autofagia/efeitos dos fármacos , Autofagia/fisiologia , AMP Cíclico/metabolismo , Modelos Animais de Doenças , Humanos , Masculino , Camundongos Transgênicos , Fármacos Neuroprotetores/farmacologia , Células PC12 , Doença de Parkinson/metabolismo , Doença de Parkinson/patologia , Complexo de Endopeptidases do Proteassoma/metabolismo , Ratos , Ubiquitina/metabolismo , Regulação para Cima/efeitos dos fármacos , alfa-Sinucleína/genéticaRESUMO
CONTEXT: A host of microRNAs have been reported to suppress tumor growth, invasion, and metastasis and play roles in neurodegeneration disorders. Moreover, microRNA changes are found in the peripheral blood, cerebrospinal fluid (CSF), and brain tissues of central nervous system diseases, including glioma, Alzheimer's disease (AD), Parkinson's disease (PD), multiple sclerosis, and depression. Compared with other body fluids, CSF can reflect the brain pathological processes more accurately. AIMS: To understand whether microRNA expression may be misregulated in patients with PD, and further discover potential diagnostic biomarkers and promising therapeutic targets for PD. MATERIALS AND METHODS: Here, through real-time reverse-transcription polymerase chain reaction (RT-PCR), we compared CSF microRNA from 15 PD patients, 11 AD patients, and 16 controls with other neurologic disorders, such as encephalitis and Guillain-Barre syndrome. RESULTS: Finally, we identified hsa-miR-626 changes in the CSF of PD patients. The mean expression level of hsa-miR-626 was significantly reduced in the CSF of PD patients compared with AD patients and controls. CONCLUSIONS: Our approach provides a preliminary research for identifying biomarkers in the CSF that could be used for the detection, diagnosis, and monitoring of PD.
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Doença de Alzheimer , MicroRNAs , Doença de Parkinson , Biomarcadores , Humanos , MicroRNAs/genética , Doença de Parkinson/genéticaRESUMO
AIMS: Cyclin-dependent kinase 5 (CDK5) is a potential target for the treatment of cerebral ischemia. CDK5 is one of the upstream regulators for Dynamin-related protein 1 (Drp1) phosphorylation. This study intends to discuss whether CDK5 inhibition conferring neuroprotection in cerebral ischemia through regulating Drp1 phosphorylation. MATERIALS AND METHODS: Mouse neuroblastoma N2a cells and N1E-115 cells were cultured and subjected to oxygen-glucose deprivation/reperfusion (OGDR). N2a cells and N1E-115 cells were treated with Roscovitine, a pharmacological inhibitor of CDK5, or transfected with CDK5 siRNA to knock down CDK5 expression. N2a cells were transfected with different plasmids (Drp1-Myc, the dephosphorylation-mimic mutant Drp1S616A-Myc and the phosphorylation-mimic mutant Drp1S616D-Myc). The expression of CDK5 and its activator p35, Drp1 and phosphorylated Drp1 on S616 was determined by western blot. The morphology of mitochondria was detected by immunofluorescence staining and the proportion of N2a cells with apoptosis was detected by flow cytometry analysis. KEY FINDINGS: Expression of CDK5, p35 and phosphorylated Drp1 on S616 was strongly upregulated after 4 h and 12 h reperfusion following 4 h oxygen-glucose deprivation (OGD) at protein level. CDK5 inhibition by pre-treated with Roscovitine or transfection with CDK5 siRNA significantly ameliorated OGDR induced mitochondrial fragmentation and apoptosis. Overexpression of the phosphorylation-mimic mutant Drp1S616D abrogated the protective effect of CDK5 inhibition against OGDR induced mitochondrial fragmentation and apoptosis. SIGNIFICANCE: Our data indicate that the neuroprotective effect of CDK5 inhibition against OGDR induced neuronal damage is Drp1S616 phosphorylation dependent. A better understanding of the neuroprotective mechanisms of CDK5 inhibition in cerebral ischemia will help to develop safe and efficacious drugs targeting CDK5 signaling for clinical use.
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Apoptose , Quinase 5 Dependente de Ciclina/antagonistas & inibidores , Dinaminas/metabolismo , Glucose/deficiência , Mitocôndrias/patologia , Neuroblastoma/prevenção & controle , Oxigênio/metabolismo , Animais , Quinase 5 Dependente de Ciclina/genética , Quinase 5 Dependente de Ciclina/metabolismo , Dinaminas/genética , Camundongos , Mitocôndrias/metabolismo , Neuroblastoma/metabolismo , Neuroblastoma/patologia , Fármacos Neuroprotetores , Fosforilação , Traumatismo por Reperfusão/complicações , Transdução de Sinais , Células Tumorais CultivadasRESUMO
BACKGROUND: A recent study on early onset Parkinson's disease (PD) revealed that NUS1 is a risk gene for PD. Clinically, essential tremor (ET) is closely related to PD. In this study, we aimed to detect NUS1 variants and assess the effect of those variants on patients with ET. METHODS: The 5 coding regions and the exon-intron boundaries of NUS1 were directly sequenced in 395 patients with ET and an equal number of healthy controls, matched for age and sex. The function of variants was assessed by pathogenic predictive software programs. Genetic analysis of variants was used to evaluate susceptibility to ET. RESULTS: A total of 6 exonic variants were identified, including 3 synonymous and 3 missense variants. The non-synonymous variants were predicted to be tolerable. No variants had significant association with ET (none of the p-values were less than 0.05, using Fisher's exact test). CONCLUSION: Our study suggested that NUS1 variants may not contribute to the risk of ET.
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Tremor Essencial/genética , Receptores de Superfície Celular/genética , Adulto , Idoso , Povo Asiático , Estudos de Casos e Controles , China/epidemiologia , Tremor Essencial/epidemiologia , Éxons/genética , Feminino , Predisposição Genética para Doença/epidemiologia , Variação Genética , Ensaios de Triagem em Larga Escala , Humanos , Íntrons/genética , Masculino , Programas de Rastreamento , Pessoa de Meia-Idade , Mutação de Sentido Incorreto/genética , SoftwareRESUMO
Wnt signaling through the Frizzled (FZD) family of serpentine receptors is essential for embryogenesis and homeostasis, and stringent control of the FZD protein level is critical for stem cell regulation. Through CRISPR/Cas9 genome-wide screening in human cells, we identified TMEM79/MATTRIN, an orphan multi-span transmembrane protein, as a specific inhibitor of Wnt/FZD signaling. TMEM79 interacts with FZD during biogenesis and promotes FZD degradation independent of ZNRF3/RNF43 ubiquitin ligases (R-spondin receptors). TMEM79 interacts with ubiquitin-specific protease 8 (USP8), whose activating mutations underlie human tumorigenesis. TMEM79 specifically inhibits USP8 deubiquitination of FZD, thereby governing USP8 substrate specificity and promoting FZD degradation. Tmem79 and Usp8 genes have a pre-bilaterian origin, and Tmem79 inhibition of Usp8 and Wnt signaling is required for anterior neural development and gastrulation in Xenopus embryos. TMEM79 is a predisposition gene for Atopic dermatitis, suggesting deregulation of Wnt/FZD signaling a possible cause for this most common yet enigmatic inflammatory skin disease.
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Desenvolvimento Embrionário/fisiologia , Receptores Frizzled/metabolismo , Proteínas de Membrana/metabolismo , Xenopus laevis/embriologia , Animais , Desenvolvimento Embrionário/genética , Receptores Frizzled/genética , Células HEK293 , Humanos , Proteínas de Membrana/genética , Via de Sinalização Wnt/genética , Xenopus laevis/genéticaRESUMO
BACKGROUND: The zinc finger protein 587B (ZNF587B) is a novel cisplatin-sensitive gene that was identified in our previous research by using a genome-scale CRISPR-Cas9 knockout library in ovarian cancer (OC) cell lines. ZNF587B belongs to the C2H2-type zinc finger protein (ZFP) family. Many ZFP protein could inhibit tumor development and malignancy. However, the function of ZNF587B remains unknown. METHODS: Quantitative PCR (qPCR) was utilized to compare ZNF587B mRNA expression levels in OC and normal ovarian cell lines. The small interfering RNA (siRNA) and full-length ZNF587B eukaryotic expression plasmid were constructed and transfected into OC cells later. Colony formation, 5-ethynyl-2'-deoxyuridine (EdU) assay, transwell assay, and xenograft experiment were conducted to evaluate the effect of ZNF587B on OC cells. RESULTS: ZNF587B was downregulated by approximately 43% and 17% in the OC cell lines SKOV3 and A2780, respectively, compared with that in the normal ovarian cell line IOSE80. Overexpression of ZNF587B reduced cell proliferation, colony formation, migration, and invasion, which could be reversed by knockdown of ZNF587B via siRNA. Xenograft experiments also confirmed that ZNF587B could suppress tumor growth. Survival data of OC patients in the SurvExpress database showed that with respect to overall survival, low-risk patients grouped by the prognostic index had a higher expression of ZNF587B and a better prognosis than high-risk group (HR = 1.77, 95% CI: 0.55-0.70, p = 0.023). Moreover, overexpression of ZNF587B promoted OC cells apoptosis when pretreated with cisplatin. CONCLUSION: ZNF587B is a novel potential tumor suppressor of OC and may be a therapeutic target for OC.
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Recanalization therapy by intravenous thrombolysis or endovascular therapy is critical for the treatment of cerebral infarction. However, the recanalization treatment will also exacerbate acute brain injury and even severely threatens human life due to the reperfusion injury. So far, the underlying mechanisms for cerebral ischaemia-reperfusion injury are poorly understood and effective therapeutic interventions are yet to be discovered. Therefore, in the research, we subjected SK-N-BE(2) cells to oxygen-glucose deprivation/reperfusion (OGDR) insult and performed a pooled genome-wide CRISPR (clustered regularly interspaced short palindromic repeats)/Cas9 (CRISPR-associated protein 9) knockout screen to discover new potential therapeutic targets for cerebral ischaemia-reperfusion injury. We used Metascape to identify candidate genes which might involve in OGDR resistance. We found that the genes contributed to OGDR resistance were primarily involved in neutrophil degranulation, mitochondrial translation, and regulation of cysteine-type endopeptidase activity involved in apoptotic process and response to oxidative stress. We then knocked down some of the identified candidate genes individually. We demonstrated that MRPL19, MRPL32, MRPL52 and MRPL51 inhibition increased cell viability and attenuated OGDR-induced apoptosis. We also demonstrated that OGDR down-regulated the expression of MRPL19 and MRPL51 protein. Taken together, our data suggest that genome-scale screening with Cas9 is a reliable tool to analyse the cellular systems that respond to OGDR injury. MRPL19 and MRPL51 contribute to OGDR resistance and are supposed to be promising targets for the treatment of cerebral ischaemia-reperfusion damage.
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Sistemas CRISPR-Cas , Glucose/deficiência , Proteínas Mitocondriais/antagonistas & inibidores , Neuroblastoma/patologia , Oxigênio/metabolismo , Traumatismo por Reperfusão/fisiopatologia , Proteínas Ribossômicas/antagonistas & inibidores , Regulação da Expressão Gênica , Humanos , Proteínas Mitocondriais/genética , Neuroblastoma/genética , Neuroblastoma/metabolismo , Estresse Oxidativo , Proteínas Ribossômicas/genética , Células Tumorais CultivadasRESUMO
Autophagy is a basic catabolic response that eukaryotic cells use to degrade unnecessary or dysfunctional cellular components in an orderly and regulated manner. It plays important roles in maintaining cellular homeostasis, energy homeostasis, response to environmental stimuli, and the development of cancer. In solid tumors, hypoxia induces an increased HIF-1a that activates autophagy. However, the exact mechanism by which induced HIF-1a stimulates autophagy in cancer cells remains elusive. In the present study, we confirmed that ANKRD37 is upregulated in colon cancer tissue. Moreover, the higher expression level of ANKRD37 is related to a poorer survival rate. Using RNA interference, immunoblot, and immunofluorescence, we discovered that in cancer cell line RKO, hypoxia-induced HIF-1a regulates autophagy activity by increasing ANKRD37 level. In addition, intranuclear ANKRD37 played an important role in the regulation of hypoxia-induced autophagy. The translocation of ANKRD37 into cell nuclear is required for promoting cell growth and HIF-1a induced autophagy. These findings provide new insights to understand the hypoxia regulation mechanisms and the role of autophagy in cancer development.
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Autofagia/efeitos dos fármacos , Neoplasias do Colo/genética , Regulação Neoplásica da Expressão Gênica/genética , Subunidade alfa do Fator 1 Induzível por Hipóxia/genética , Autofagia/genética , Autofagia/fisiologia , Hipóxia Celular/efeitos dos fármacos , Hipóxia Celular/fisiologia , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Proliferação de Células/fisiologia , Neoplasias do Colo/metabolismo , Neoplasias do Colo/patologia , Humanos , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Subunidade alfa do Fator 1 Induzível por Hipóxia/farmacologia , Interferência de RNA/efeitos dos fármacos , Interferência de RNA/fisiologia , Ativação Transcricional/fisiologiaRESUMO
BACKGROUND: Echinococcosis is a chronic zoonosis caused by tapeworms of the genus Echinococcus. Treatment of the disease is often expensive and complicated, sometimes requiring extensive surgery. Ultrasonographic imaging is currently the main technique for diagnosis, while immunological analysis provides additional information. Confirmation still needs pathological analysis. However, these diagnostic techniques generally detect infection in late stages of the disease. An accurate, early and non-invasive molecular diagnostic method is still unavailable. METHODOLOGY/PRINCIPAL FINDINGS: We sequenced the cell-free DNA (cfDNA) from plasma of echinococcosis patients and confirmed the presence of Echinococcus DNA. To improve detection sensitivity, we developed a method based on targeted next-generation sequencing of repeat regions. Simulation experiments demonstrate that the targeted sequencing is sensitive enough to detect as little as 0.1% of an Echinococcus genome in 1 mL of plasma. Results obtained using patient plasma shows that the Area Under the Curve (AUC) of the method is 0.862, with a detection sensitivity of 62.50% and specificity of 100%, corresponding to a Youden-index of 0.625. CONCLUSIONS/SIGNIFICANCE: This study provides evidence that hydatid cysts release cfDNA fragments into patient plasma. Using the repeat region targeted sequencing method, highly specific detection of Echinococcus infection was achieved. This study paves a new avenue for potential non-invasive screening and diagnosis of echinococcosis.
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DNA de Helmintos/sangue , Equinococose/diagnóstico , Echinococcus/genética , Técnicas de Diagnóstico Molecular/métodos , Plasma/química , Sequências Repetitivas de Ácido Nucleico , Adulto , Animais , DNA de Helmintos/química , DNA de Helmintos/genética , DNA de Helmintos/isolamento & purificação , Feminino , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Humanos , Masculino , Sensibilidade e EspecificidadeRESUMO
Autophagy, a conserved cellular degradation and recycling process, can be enhanced by nutrient depletion, oxidative stress or other harmful conditions to maintain cell survival. 6-Hydroxydopamine/ascorbic acid (6-OHDA/AA) is commonly used to induce experimental Parkinson's disease (PD) lesions by causing oxidative damage to dopaminergic neurons. Activation of autophagy has been observed in the 6-OHDA-induced PD models. However, the mechanism and exact role of autophagy activation in 6-OHDA PD model remain inconclusive. In this study, we report that autophagy was triggered via mucolipin 1/calcium/calcineurin/TFEB (transcription factor EB) pathway upon oxidative stress induced by 6-OHDA/AA. Interestingly, overexpression of TFEB alleviated 6-OHDA/AA toxicity. Moreover, autophagy enhancers, Torin1 (an mTOR-dependent TFEB/autophagy enhancer) and curcumin analog C1 (a TFEB-dependent and mTOR-independent autophagy enhancer), significantly rescued 6-OHDA/AA-induced cell death in SH-SY5Y cells, iPSC-derived DA neurons and mice nigral DA neurons. The behavioral abnormality of 6-OHDA/AA-treated mice can also be rescued by Torin 1 or C1 administration. The protective effects of Torin 1 and C1 can be blocked by autophagy inhibitors like chloroquine (CQ) or by knocking down autophagy-related genes TFEB and ATG5. Taken together, this study supports that TFEB-mediated autophagy is a survival mechanism during oxidative stress and pharmacological enhancement of this process is a neuroprotective strategy against oxidative stress-associated PD lesions.
Assuntos
Antiparkinsonianos/farmacologia , Autofagia/efeitos dos fármacos , Fatores de Transcrição de Zíper de Leucina e Hélice-Alça-Hélix Básicos/metabolismo , Encéfalo/efeitos dos fármacos , Curcumina/farmacologia , Neurônios Dopaminérgicos/efeitos dos fármacos , Naftiridinas/farmacologia , Estresse Oxidativo/efeitos dos fármacos , Transtornos Parkinsonianos/tratamento farmacológico , Animais , Ácido Ascórbico , Fatores de Transcrição de Zíper de Leucina e Hélice-Alça-Hélix Básicos/genética , Comportamento Animal/efeitos dos fármacos , Encéfalo/metabolismo , Encéfalo/patologia , Linhagem Celular Tumoral , Curcumina/análogos & derivados , Modelos Animais de Doenças , Neurônios Dopaminérgicos/metabolismo , Neurônios Dopaminérgicos/patologia , Feminino , Humanos , Camundongos Endogâmicos C57BL , Mitofagia/efeitos dos fármacos , Oxidopamina , Transtornos Parkinsonianos/induzido quimicamente , Transtornos Parkinsonianos/metabolismo , Transtornos Parkinsonianos/patologia , Transdução de Sinais , Serina-Treonina Quinases TOR/antagonistas & inibidores , Serina-Treonina Quinases TOR/metabolismoRESUMO
The canonical Wnt signalling pathway is a critical pathway involved in the proliferation of cells. It has been well-established that it plays the central role during colorectal carcinogenesis and development. Yet the exact molecular mechanism of how the canonical Wnt pathway is fine-tuned remains elusive. We found that SLC35C1, a GDP-fucose transporter, negatively regulates the Wnt signalling pathway. We show here that SLC35C1 is reduced in all colon cancer by both immunohistochemistry images and TCGA data, whereas ß-catenin is increased. Down-regulation of SLC35C1 is also detected by real-time PCR in stage 3 and stage 4 colorectal cancer tissues. Moreover, analysing the TCGA database with cBioPortal reveals the negative correlation of SLC35C1 mRNA level to the expression of ß-catenin. Reduced SLC35C1 significantly promotes cell proliferation and colony formation of HEK293 cells. Meanwhile, in HEK293 cells silencing SLC35C1 activates canonical Wnt pathway, whereas overexpressing SLC35C1 inhibits it. Consistently, the reduction of SLC35C1 in HEK293 cells also elevated the mRNA level of Wnt target genes C-myc, Axin2 and Cyclin D1, as well as the secretion of Wnt3a. In conclusion, we identified SLC35C1 as a negative regulator of the Wnt signalling pathway in colon cancer. Decreased SLC35C1 may cause over-activation of Wnt signalling in colorectal cancer.
Assuntos
Neoplasias do Colo/genética , Proteínas de Transporte de Monossacarídeos/genética , Proteína Wnt3A/genética , beta Catenina/genética , Linhagem Celular Tumoral , Proliferação de Células/genética , Neoplasias do Colo/patologia , Ciclina D1/genética , Regulação Neoplásica da Expressão Gênica/genética , Células HEK293 , Humanos , Proteínas Proto-Oncogênicas c-myc/genética , Via de Sinalização Wnt/genéticaRESUMO
Nitric oxide (NO) is an important mediator of inflammation response and the production of NO has been linked to a variety of diseases, including tumors, inflammation and central nervous system diseases. In macrophages, a high level of NO is generated by iNOS during inflammatory responses triggered by cytokines or pathogens. Autophagy, a cellular bulk degradation process via lysosome, has been implicated in many disease conditions including inflammation. In this study, we have reported the previously unknown role of autophagy in regulating iNOS levels in macrophages, both under basal and Lipopolysaccharides (LPS)-induced conditions. Our data showed that iNOS levels accumulated upon autophagy inhibition and decreased upon autophagy induction. iNOS interacted and co-localized with autophagy receptor p62/SQSTM1, especially under LPS-stimulated condition in macrophages. Moreover, the immunostaining data revealed that iNOS also co-localizes with the autophagosome marker LC3 and lysosome marker LAMP1, especially under lysosomal inhibition conditions, indicating iNOS is an autophagy substrate. Finally, we showed that autophagy negatively regulated the generation of NO in macrophages, which is consistent with the changes of iNOS levels. Collectively, our study revealed a previously unknown mechanism by which autophagy regulates iNOS levels to modulate NO production during inflammation.