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1.
Int J Mol Sci ; 22(19)2021 Oct 06.
Artigo em Inglês | MEDLINE | ID: mdl-34639129

RESUMO

Multiple sclerosis (MS) is an inflammatory disease of the central nervous system that finally leads to demyelination. Demyelinating optic neuritis is a frequent symptom in MS. Recent studies also revealed synapse dysfunctions in MS patients and MS mouse models. We previously reported alterations of photoreceptor ribbon synapses in the experimental auto-immune encephalomyelitis (EAE) mouse model of MS. In the present study, we found that the previously observed decreased imunosignals of photoreceptor ribbons in early EAE resulted from a decrease in synaptic ribbon size, whereas the number/density of ribbons in photoreceptor synapses remained unchanged. Smaller photoreceptor ribbons are associated with fewer docked and ribbon-associated vesicles. At a functional level, depolarization-evoked exocytosis as monitored by optical recording was diminished even as early as on day 7 after EAE induction. Moreover compensatory, post-depolarization endocytosis was decreased. Decreased post-depolarization endocytosis in early EAE correlated with diminished synaptic enrichment of dynamin3. In contrast, basal endocytosis in photoreceptor synapses of resting non-depolarized retinal slices was increased in early EAE. Increased basal endocytosis correlated with increased de-phosphorylation of dynamin1. Thus, multiple endocytic pathways in photoreceptor synapse are differentially affected in early EAE and likely contribute to the observed synapse pathology in early EAE.


Assuntos
Modelos Animais de Doenças , Encefalomielite Autoimune Experimental/patologia , Endocitose , Exocitose , Esclerose Múltipla/patologia , Células Fotorreceptoras Retinianas Bastonetes/patologia , Sinapses/patologia , Animais , Dinaminas/metabolismo , Encefalomielite Autoimune Experimental/etiologia , Encefalomielite Autoimune Experimental/metabolismo , Feminino , Camundongos , Camundongos Endogâmicos C57BL , Esclerose Múltipla/etiologia , Esclerose Múltipla/metabolismo , Fosforilação , Retina/metabolismo , Retina/patologia , Células Fotorreceptoras Retinianas Bastonetes/metabolismo , Sinapses/metabolismo , Vesículas Sinápticas/metabolismo , Vesículas Sinápticas/patologia
2.
Nat Cell Biol ; 23(10): 1073-1084, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34616024

RESUMO

Spatially controlled, cargo-specific endocytosis is essential for development, tissue homeostasis and cancer invasion. Unlike cargo-specific clathrin-mediated endocytosis, the clathrin- and dynamin-independent endocytic pathway (CLIC-GEEC, CG pathway) is considered a bulk internalization route for the fluid phase, glycosylated membrane proteins and lipids. While the core molecular players of CG-endocytosis have been recently defined, evidence of cargo-specific adaptors or selective uptake of proteins for the pathway are lacking. Here we identify the actin-binding protein Swiprosin-1 (Swip1, EFHD2) as a cargo-specific adaptor for CG-endocytosis. Swip1 couples active Rab21-associated integrins with key components of the CG-endocytic machinery-Arf1, IRSp53 and actin-and is critical for integrin endocytosis. Through this function, Swip1 supports integrin-dependent cancer-cell migration and invasion, and is a negative prognostic marker in breast cancer. Our results demonstrate a previously unknown cargo selectivity for the CG pathway and a role for specific adaptors in recruitment into this endocytic route.


Assuntos
Neoplasias da Mama/patologia , Clatrina/metabolismo , Dinaminas/metabolismo , Endocitose , Integrina beta1/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Proteínas rab de Ligação ao GTP/metabolismo , Actinas/metabolismo , Transporte Biológico , Neoplasias da Mama/genética , Neoplasias da Mama/metabolismo , Movimento Celular , Clatrina/genética , Dinaminas/genética , Feminino , Humanos , Integrina beta1/genética , Peptídeos e Proteínas de Sinalização Intracelular/genética , Proteínas rab de Ligação ao GTP/genética
3.
Poult Sci ; 100(11): 101470, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34624771

RESUMO

Endodermal epithelial cells (EECs) within the yolk sac membrane (YSM) of avian embryos are responsible for the absorption and utilization of lipids. The lipids in the yolk are mostly composed of very low density lipoprotein (VLDL), uptake mainly depends on clathrin-mediated endocytosis (CME). The CME relies on vesicle formation through the regulation of dynamin (DNM). However, it is still unclear whether DNMs participate in avian embryonic development. We examined mRNA expression levels of several genes involved in lipid transportation and utilization in YSM during Japanese quail embryonic development using qPCR. The mRNA levels of DNM1 and DNM3 were elevated at incubation d 8 and 10 before the increase of SOAT1, CIDEA, CIDEC, and APOB mRNA's. The elevated gene expression suggested the increased demand for DNM activity might be prior to cholesteryl ester production, lipid storage, and VLDL transport. Hinted by the result, we further investigated the role of DNMs in the embryonic development of Japanese quail. A DNM inhibitor, dynasore, was injected into fertilized eggs at incubation d 3. At incubation d 10, the dynasore-injected embryo showed increased embryonic lethality compared to control groups. Thus, the activity of DNMs was essential for the embryonic development of Japanese quail. The activities of DNMs were also verified by the absorptions of fluorescent VLDL (DiI-yVLDL) in EECs. Fluorescent signals in EECs were decreased significantly after treatment with dynasore. Finally, EECs were pretreated with S-Nitroso-L-glutathione (GSNO), a DNM activator, for 30 min; this increased the uptake of DiI-yVLDL. In conclusion, DNMs serve a critical role in mediating lipid absorption in YSM. The activity of DNMs was an integral part of development in Japanese quail. Our results suggest enhancing lipid transportation through an increase of DNM activity may improve avian embryonic development.


Assuntos
Coturnix , Saco Vitelino , Animais , Galinhas , Dinaminas , Desenvolvimento Embrionário , Células Epiteliais , Lipídeos
4.
Nat Methods ; 18(10): 1247-1252, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34608319

RESUMO

The quantification of membrane-associated biomolecular interactions is crucial to our understanding of various cellular processes. State-of-the-art single-molecule approaches rely largely on the addition of fluorescent labels, which complicates the quantification of the involved stoichiometries and dynamics because of low temporal resolution and the inherent limitations associated with labeling efficiency, photoblinking and photobleaching. Here, we demonstrate dynamic mass photometry, a method for label-free imaging, tracking and mass measurement of individual membrane-associated proteins diffusing on supported lipid bilayers. Application of this method to the membrane remodeling GTPase, dynamin-1, reveals heterogeneous mixtures of dimer-based oligomers, oligomer-dependent mobilities, membrane affinities and (dis)association of individual complexes. These capabilities, together with assay-based advances for studying integral membrane proteins, will enable the elucidation of biomolecular mechanisms in and on lipid bilayers.


Assuntos
Dinaminas/química , Bicamadas Lipídicas/química , Fotometria/métodos , Proteínas/química
5.
Int J Mol Sci ; 22(18)2021 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-34575944

RESUMO

Mitigation of calcium-dependent destruction of skeletal muscle mitochondria is considered as a promising adjunctive therapy in Duchenne muscular dystrophy (DMD). In this work, we study the effect of intraperitoneal administration of a non-immunosuppressive inhibitor of calcium-dependent mitochondrial permeability transition (MPT) pore alisporivir on the state of skeletal muscles and the functioning of mitochondria in dystrophin-deficient mdx mice. We show that treatment with alisporivir reduces inflammation and improves muscle function in mdx mice. These effects of alisporivir were associated with an improvement in the ultrastructure of mitochondria, normalization of respiration and oxidative phosphorylation, and a decrease in lipid peroxidation, due to suppression of MPT pore opening and an improvement in calcium homeostasis. The action of alisporivir was associated with suppression of the activity of cyclophilin D and a decrease in its expression in skeletal muscles. This was observed in both mdx mice and wild-type animals. At the same time, alisporivir suppressed mitochondrial biogenesis, assessed by the expression of Ppargc1a, and altered the dynamics of organelles, inhibiting both DRP1-mediated fission and MFN2-associated fusion of mitochondria. The article discusses the effects of alisporivir administration and cyclophilin D inhibition on mitochondrial reprogramming and networking in DMD and the consequences of this therapy on skeletal muscle health.


Assuntos
Dinaminas/genética , Distrofina/genética , GTP Fosfo-Hidrolases/genética , Distrofia Muscular de Duchenne/tratamento farmacológico , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo/genética , Animais , Ciclofilinas/genética , Ciclosporina/farmacologia , Regulação da Expressão Gênica/efeitos dos fármacos , Humanos , Camundongos , Camundongos Endogâmicos mdx , Mitocôndrias/efeitos dos fármacos , Mitocôndrias Musculares/efeitos dos fármacos , Mitocôndrias Musculares/genética , Dinâmica Mitocondrial/efeitos dos fármacos , Poro de Transição de Permeabilidade Mitocondrial/farmacologia , Músculo Esquelético/efeitos dos fármacos , Músculo Esquelético/metabolismo , Distrofia Muscular de Duchenne/genética , Distrofia Muscular de Duchenne/patologia
6.
Int J Mol Sci ; 22(18)2021 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-34575980

RESUMO

Mitochondrial impairments in dynamic behavior (fusion/fission balance) associated with mitochondrial dysfunction play a key role in cell lipotoxicity and lipid-induced metabolic diseases. The present work aimed to evaluate dose- and time-dependent effects of the monounsaturated fatty acid oleate on mitochondrial fusion/fission proteins in comparison with the saturated fatty acid palmitate in hepatic cells. To this end, HepG-2 cells were treated with 0, 10 µM, 50 µM, 100 µM, 250 µM or 500 µM of either oleate or palmitate for 8 or 24 h. Cell viability and lipid accumulation were evaluated to assess lipotoxicity. Mitochondrial markers of fusion (mitofusin 2, MFN2) and fission (dynamin-related protein 1, DRP1) processes were evaluated by Western blot analysis. After 8 h, the highest dose of oleate induced a decrease in DRP1 content without changes in MFN2 content in association with cell viability maintenance, whereas palmitate induced a decrease in cell viability associated with a decrease mainly in MFN2 content. After 24 h, oleate induced MFN2 increase, whereas palmitate induced DRP1 increase associated with a higher decrease in cell viability with high doses compared to oleate. This finding could be useful to understand the role of mitochondria in the protective effects of oleate as a bioactive compound.


Assuntos
Dinaminas/genética , GTP Fosfo-Hidrolases/genética , Doenças Metabólicas/genética , Dinâmica Mitocondrial/efeitos dos fármacos , Proteínas Mitocondriais/genética , Ácido Oleico/metabolismo , Sobrevivência Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Ácidos Graxos Monoinsaturados/farmacologia , Regulação da Expressão Gênica/efeitos dos fármacos , Células Hep G2 , Humanos , Metabolismo dos Lipídeos/efeitos dos fármacos , Lipídeos/toxicidade , Doenças Metabólicas/etiologia , Doenças Metabólicas/metabolismo , Doenças Metabólicas/patologia , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/genética , Mitocôndrias/patologia , Dinâmica Mitocondrial/genética , Ácido Oleico/farmacologia , Palmitatos/metabolismo , Palmitatos/farmacologia
7.
Nat Commun ; 12(1): 5305, 2021 09 06.
Artigo em Inglês | MEDLINE | ID: mdl-34489447

RESUMO

Mitochondrial dysfunction is a common hallmark of neurological disorders, and reducing mitochondrial damage is considered a promising neuroprotective therapeutic strategy. Here, we used high-throughput small molecule screening to identify CHIR99021 as a potent enhancer of mitochondrial function. CHIR99021 improved mitochondrial phenotypes and enhanced cell viability in several models of Huntington's disease (HD), a fatal inherited neurodegenerative disorder. Notably, CHIR99201 treatment reduced HD-associated neuropathology and behavioral defects in HD mice and improved mitochondrial function and cell survival in HD patient-derived neurons. Independent of its known inhibitory activity against glycogen synthase kinase 3 (GSK3), CHIR99021 treatment in HD models suppressed the proteasomal degradation of calpastatin (CAST), and subsequently inhibited calpain activation, a well-established effector of neural death, and Drp1, a driver of mitochondrial fragmentation. Our results established CAST-Drp1 as a druggable signaling axis in HD pathogenesis and highlighted CHIR99021 as a mitochondrial function enhancer and a potential lead for developing HD therapies.


Assuntos
Proteínas de Ligação ao Cálcio/genética , Dinaminas/genética , Doença de Huntington/genética , Mitocôndrias/efeitos dos fármacos , Fármacos Neuroprotetores/farmacologia , Piridinas/farmacologia , Pirimidinas/farmacologia , Animais , Proteínas de Ligação ao Cálcio/metabolismo , Calpaína/genética , Calpaína/metabolismo , Corpo Estriado/efeitos dos fármacos , Corpo Estriado/metabolismo , Corpo Estriado/patologia , Modelos Animais de Doenças , Dinaminas/metabolismo , Regulação da Expressão Gênica , Glicogênio Sintase Quinase 3 beta/antagonistas & inibidores , Glicogênio Sintase Quinase 3 beta/genética , Glicogênio Sintase Quinase 3 beta/metabolismo , Humanos , Doença de Huntington/tratamento farmacológico , Doença de Huntington/metabolismo , Doença de Huntington/patologia , Injeções Intraperitoneais , Masculino , Camundongos , Mitocôndrias/metabolismo , Mitocôndrias/patologia , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Neurônios/patologia , Cultura Primária de Células , Complexo de Endopeptidases do Proteassoma/metabolismo , Proteólise , Transdução de Sinais
8.
J Hazard Mater ; 416: 126177, 2021 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-34492951

RESUMO

Previous study showed that lead (Pb) could induce ATM-dependent mitophagy. However, whether Pb has any impact on mitochondrial fusion and fission, the upstream events of mitophagy, and how ATM connects to these processes remain unclear. In this study, we found that Pb can disrupt mitochondrial network morphology as indicated by increased percentage of shortened mitochondria and by decreased mitochondrial footprints. Correspondingly, the expression of fission protein Drp1 and its association with mitochondrial marker Hsp60 were significantly increased, while those of fusion proteins Mfn2 and Opa1 and their co-localization with Hsp60 were drastically attenuated. Notably, the expression of p-Drp1 (Ser616) and its translocation to mitochondria were dramatically elevated. Moreover, a small amount of ATM could be detected in the cytoplasm around mitochondria in response to Pb, and the co-localization of p-ATM (Ser1981) with Drp1 and p-Drp1 (Ser616) was obviously increased while its co-localization with Mfn2 and Opa1 was dramatically decreased. Furthermore, siRNA silencing of ATM evidently promoted greater fission in response to Pb stress, indicating that ATM is involved in mitochondrial fragmentation. Our results suggest that cytoplasmic ATM is an important regulator of Pb-induced mitochondrial fission.


Assuntos
Chumbo , Dinâmica Mitocondrial , Dinaminas , Fibroblastos , GTP Fosfo-Hidrolases/genética , Proteínas Associadas aos Microtúbulos , Proteínas Mitocondriais/genética
9.
J Biol Chem ; 297(4): 101196, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34529976

RESUMO

Mitochondria undergo continuous cycles of fission and fusion to promote inheritance, regulate quality control, and mitigate organelle stress. More recently, this process of mitochondrial dynamics has been demonstrated to be highly sensitive to nutrient supply, ultimately conferring bioenergetic plasticity to the organelle. However, whether regulators of mitochondrial dynamics play a causative role in nutrient regulation remains unclear. In this study, we generated a cellular loss-of-function model for dynamin-related protein 1 (DRP1), the primary regulator of outer membrane mitochondrial fission. Loss of DRP1 (shDRP1) resulted in extensive ultrastructural and functional remodeling of mitochondria, characterized by pleomorphic enlargement, increased electron density of the matrix, and defective NADH and succinate oxidation. Despite increased mitochondrial size and volume, shDRP1 cells exhibited reduced cellular glucose uptake and mitochondrial fatty acid oxidation. Untargeted transcriptomic profiling revealed severe downregulation of genes required for cellular and mitochondrial calcium homeostasis, which was coupled to loss of ATP-stimulated calcium flux and impaired substrate oxidation stimulated by exogenous calcium. The insights obtained herein suggest that DRP1 regulates substrate oxidation by altering whole-cell and mitochondrial calcium dynamics. These findings are relevant to the targetability of mitochondrial fission and have clinical relevance in the identification of treatments for fission-related pathologies such as hereditary neuropathies, inborn errors in metabolism, cancer, and chronic diseases.


Assuntos
Sinalização do Cálcio , Dinaminas/metabolismo , Mitocôndrias Musculares/metabolismo , Dinâmica Mitocondrial , Linhagem Celular , Dinaminas/genética , Ácidos Graxos/genética , Ácidos Graxos/metabolismo , Humanos , Mitocôndrias Musculares/genética , Oxirredução
10.
Free Radic Biol Med ; 176: 149-161, 2021 11 20.
Artigo em Inglês | MEDLINE | ID: mdl-34562609

RESUMO

Corneal alkali burn, one of the most serious ophthalmic emergencies, is difficult to be cured by conservative treatments. It is well known that oxidative stress, inflammation and neovascularization are the main causes of corneal damage after alkali burn, but its underlying mechanism remains to be elucidated. Here, we reported that the expression and phosphorylation (Ser616) of mitochondrial fission protein Drp1 were up-regulated at day 3 after alkali burn, while mitochondrial fusion protein Mfn2 was down-regulated. The phosphorylation of ERK1/2 in corneas was increased at day 1, 3, 7 and peaked at day 3 after alkali burn. In human corneal epithelial cells (HCE-2), NaOH treatment induced mitochondrial fission, intracellular ROS production and mitochondrial membrane potential disruption, which was prevented by Drp1 inhibitor Mdivi-1. In corneas, Mdivi-1 or knockdown of Drp1 by Lenti-Drp1 shRNA attenuated alkali burn-induced ROS production and phosphorylation of IκBα and p65. In immunofluorescence staining, it was detected that Mdivi-1 also prevented NaOH-induced nuclear translocation of p65 in HCE-2 cells. Moreover, the expression of NADPH oxidase NOX2 and NOX4 in corneas peaked at day 7 after alkali burn. Mdivi-1, Lenti-Drp1 shRNA or the mitochondria-targeted antioxidant mito-TEMPO efficiently alleviated activation of NF-κB, expression of NOX2/4 and inflammatory cytokines including IL-6, IL-1ß and TNF-α in corneas after alkali burn. In pharmacological experiments, both Mdivi-1 and NADPH oxidases inhibitor Apocynin protected the corneas against alkali burn-induced neovascularization. Intriguingly, the combined administration of Mdivi-1 and Apocynin had a synergistic inhibitory effect on corneal neovascularization after alkali burn. Taken together, these results indicate that Drp1-dependent mitochondrial fission is involved in alkali burn-induced corneal injury through regulating oxidative stress, inflammatory responses and corneal neovascularization. This might provide a novel therapeutic target for corneal injury after alkali burn in the future.


Assuntos
Queimaduras Químicas , Lesões da Córnea , Queimaduras Químicas/tratamento farmacológico , Lesões da Córnea/induzido quimicamente , Lesões da Córnea/tratamento farmacológico , Lesões da Córnea/genética , Dinaminas/genética , Humanos , Mitocôndrias , Dinâmica Mitocondrial
11.
Zhonghua Yi Xue Yi Chuan Xue Za Zhi ; 38(9): 887-890, 2021 Sep 10.
Artigo em Chinês | MEDLINE | ID: mdl-34487538

RESUMO

OBJECTIVE: To explore the clinical features and disease-causing variants of a pediatric patient with fatal encephalopathy caused by mitochondrial peroxidase division deficiency, to identify the possible genetic causes of the disease and provide a basis for clinical diagnosis. METHODS: A child with fatal encephalopathy caused by mitochondrial peroxidase division deficiency in West China Second Hospital of Sichuan University was selected. The clinical manifestations, laboratory findings and disease-causing variant were analyzed. RESULTS: The main clinical symptoms of the patient were fever, headache and vomiting, followed by drug refractory epilepsy and progressive disturbance of consciousness. MRI showed deepening of sulcus, dilatation of bilateral ventricles, and multiple patch-like abnormal signals in paraventricular white matter, semioval center and subcortical white matter of bilateral frontal lobe. Gene detection showed a heterozygous missense variant c.1207C>T(p.Arg403Cys) in DNM1L, according to the American College of Medical Genetics and Genomics classification standards and guidelines for genetic variants, this variant was predicted to be pathogenic(PS1+PS2+PM2+PP3). After treated with gamma globulin, glucocorticoid, "mitochondrial cocktail therapy" and anti-epilepsy drugs, the condition of the patient was getting better, seizure attacks reduced and consciousness level improved. CONCLUSION: The c.1207C>T variant in DNM1L gene may be the disease-causing variant for the patient, and the result of genetic testing provides a basis for the clinical diagnosis in this case.


Assuntos
Epilepsia Resistente a Medicamentos , Peroxidase , Criança , Dinaminas , Genômica , Humanos , Mitocôndrias , Mutação , Convulsões
12.
Elife ; 102021 09 21.
Artigo em Inglês | MEDLINE | ID: mdl-34545812

RESUMO

Gene knockout of the master regulator of mitochondrial fission, Drp1, prevents neoplastic transformation. Also, mitochondrial fission and its opposing process of mitochondrial fusion are emerging as crucial regulators of stemness. Intriguingly, stem/progenitor cells maintaining repressed mitochondrial fission are primed for self-renewal and proliferation. Using our newly derived carcinogen transformed human cell model, we demonstrate that fine-tuned Drp1 repression primes a slow cycling 'stem/progenitor-like state', which is characterized by small networks of fused mitochondria and a gene-expression profile with elevated functional stem/progenitor markers (Krt15, Sox2 etc) and their regulators (Cyclin E). Fine tuning Drp1 protein by reducing its activating phosphorylation sustains the neoplastic stem/progenitor cell markers. Whereas, fine-tuned reduction of Drp1 protein maintains the characteristic mitochondrial shape and gene-expression of the primed 'stem/progenitor-like state' to accelerate neoplastic transformation, and more complete reduction of Drp1 protein prevents it. Therefore, our data highlights a 'goldilocks' level of Drp1 repression supporting stem/progenitor state dependent neoplastic transformation.


Assuntos
Transformação Celular Neoplásica/metabolismo , Dinaminas/metabolismo , Dinâmica Mitocondrial , Células-Tronco/metabolismo , Animais , Proliferação de Células , Transformação Celular Neoplásica/genética , Ciclina E/genética , Ciclina E/metabolismo , Dinaminas/genética , Células HaCaT , Humanos , Queratina-15/genética , Queratina-15/metabolismo , Queratinócitos/citologia , Queratinócitos/metabolismo , Fosforilação , Fatores de Transcrição SOXB1/genética , Fatores de Transcrição SOXB1/metabolismo
13.
Exp Cell Res ; 407(2): 112828, 2021 10 15.
Artigo em Inglês | MEDLINE | ID: mdl-34508745

RESUMO

BACKGROUND: Particulate matter≤ 2.5 µm (PM2.5) is a type of environmental agent associated with air pollution, which induces hepatic fibrosis. However, the function and mechanism of PM2.5 on hepatic stellate cell (HSC) proliferation and fibrosis remain largely unknown. METHODS: Human HSC line (LX-2) and murine HSCs were exposed to various doses of PM2.5. microRNA (miR)-411 expression was detected via quantitative reverse transcription polymerase chain reaction (qRT-PCR). Cell proliferation, fibrosis, mitochondrial dynamics dysfunction and mitophagy were determined via cell counting kit-8 (CCK-8), qRT-PCR, Western blotting and immunofluorescence. RESULTS: PM2.5 facilitated HSC proliferation and fibrosis via increasing the levels of ACTA2, Collagen 1, TIMP1 and TGF-ß1. PM2.5 reduced miR-411 expression, and contributed to mitochondrial dynamics dysfunction via increasing Drp1 and decreasing OPA1, TOM20 and PGC-1α levels. PM2.5 promoted mitophagy by upregulating the levels of Beclin-1, LC3II/I, PINK1 and Parkin. miR-411 overexpression or autophagy blockage using 3-methyladenine (3-MA) relieved PM2.5-mediated cell proliferation and fibrosis-associated factor expression in HSCs. Drp1 was targeted by miR-411. miR-411 mitigated PM2.5-induced mitophagy via targeting Drp1. Drp1 overexpression abolished the inhibitory role of miR-411 in cell proliferation and fibrosis-associated factor levels in HSCs. CONCLUSION: PM2.5 induced HSC activation and fibrosis via promoting Drp1-mediated mitophagy by decreasing miR-411, thereby causing liver fibrosis.


Assuntos
Dinaminas/metabolismo , Células Estreladas do Fígado/patologia , Cirrose Hepática/patologia , MicroRNAs/genética , Dinâmica Mitocondrial , Mitofagia , Material Particulado/efeitos adversos , Animais , Autofagia , Proliferação de Células , Dinaminas/genética , Células Estreladas do Fígado/efeitos dos fármacos , Células Estreladas do Fígado/metabolismo , Humanos , Cirrose Hepática/induzido quimicamente , Cirrose Hepática/metabolismo , Camundongos , Transdução de Sinais , Inibidor Tecidual de Metaloproteinase-1/genética , Inibidor Tecidual de Metaloproteinase-1/metabolismo , Fator de Crescimento Transformador beta1/genética , Fator de Crescimento Transformador beta1/metabolismo
15.
PLoS One ; 16(9): e0256708, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34492077

RESUMO

Current chemotherapy for treatment of pediatric acute leukemia, although generally successful, is still a matter of concern due to treatment resistance, relapses and life-long side effects for a subset of patients. Inhibition of dynamin, a GTPase involved in clathrin-mediated endocytosis and regulation of the cell cycle, has been proposed as a potential anti-cancer regimen, but the effects of dynamin inhibition on leukemia cells has not been extensively addressed. Here we adopted single cell and whole-population analysis by flow cytometry and live imaging, to assess the effect of dynamin inhibition (Dynasore, Dyngo-4a, MitMAB) on pediatric acute leukemia cell lines (CCRF-CEM and THP-1), human bone marrow biopsies from patients diagnosed with acute lymphoblastic leukemia (ALL), as well as in a model of lymphoma (EL4)-induced tumor growth in mice. All inhibitors suppressed proliferation and induced pronounced caspase-dependent apoptotic cell death in CCRF-CEM and THP-1 cell lines. However, the inhibitors showed no effect on bone marrow biopsies, and did not prevent EL4-induced tumor formation in mice. We conclude that dynamin inhibition affects highly proliferating human leukemia cells. These findings form a basis for evaluation of the potential, and constraints, of employing dynamin inhibition in treatment strategies against leukemia and other malignancies.


Assuntos
Morte Celular/genética , Dinaminas/genética , Endocitose/genética , Leucemia-Linfoma Linfoblástico de Células Precursoras/genética , Animais , Apoptose/genética , Células da Medula Óssea/metabolismo , Células da Medula Óssea/patologia , Caspases/sangue , Caspases/genética , Ciclo Celular/genética , Linhagem Celular Tumoral , Criança , Dinaminas/antagonistas & inibidores , Dinaminas/sangue , Citometria de Fluxo , Xenoenxertos , Humanos , Camundongos , Pediatria , Leucemia-Linfoma Linfoblástico de Células Precursoras/sangue , Leucemia-Linfoma Linfoblástico de Células Precursoras/patologia
16.
J Integr Med ; 19(5): 418-427, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34454893

RESUMO

OBJECTIVE: Exercise, as a common non-drug intervention, is one of several lifestyle choices known to reduce the risk of cancer. Mitochondrial division has been reported to play a key role in the occurrence and transformation of hepatocellular carcinoma (HCC). This study investigated whether exercise could regulate the occurrence and development of HCC through mitosis. METHODS: Bioinformatics technology was used to analyze the expression level of dynamin-related protein 1 (DRP1), a key protein of mitochondrial division. The effects of DRP1 and DRP1 inhibitor (mdivi-1) on the proliferation and migration of liver cancer cells BEL-7402 were observed using cell counting kit-8, plate colony formation, transwell cell migration, and scratch experiments. Enzyme-linked immunosorbent assay, Western blot and real-time polymerase chain reaction were used to detect the expression of DRP1 and its downstream phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT) pathway. A treadmill exercise intervention was tested in a nude mouse human liver cancer subcutaneous tumor model expressing different levels of DRP1. The size and weight of subcutaneous tumors in mice were detected before and after exercise. RESULTS: The expression of DRP1 in liver cancer tissues was significantly upregulated compared with normal liver tissues (P < 0.001). The proliferation rate and the migration of BEL-7402 cells in the DRP1 over-expression group were higher than that in the control group. The mdivi-1 group showed an inhibitory effect on the proliferation and migration of BEL-7402 cells at 50 µmol/L. Aerobic exercise was able to inhibit the expression of DRP1 and decrease the size and weight of subcutaneous tumors. Moreover, the expression of phosphorylated PI3K (p-PI3K) and phosphorylated AKT (p-AKT) decreased in the exercise group. However, exercise could not change p-PI3K and p-AKT levels after knocking down DRP1 or using mdivi-1 on subcutaneous tumor. CONCLUSION: Aerobic exercise can suppress the development of tumors partially by regulating DRP1 through PI3K/AKT pathway.


Assuntos
Carcinoma Hepatocelular , Neoplasias Hepáticas , Animais , Apoptose , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/terapia , Linhagem Celular Tumoral , Proliferação de Células , Regulação para Baixo , Dinaminas , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/terapia , Camundongos , Fosfatidilinositol 3-Quinase/metabolismo , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Transdução de Sinais
17.
Neuron ; 109(19): 3119-3134.e5, 2021 10 06.
Artigo em Inglês | MEDLINE | ID: mdl-34411513

RESUMO

Transformation of flat membrane into round vesicles is generally thought to underlie endocytosis and produce speed-, amount-, and vesicle-size-specific endocytic modes. Visualizing depolarization-induced exocytic and endocytic membrane transformation in live neuroendocrine chromaffin cells, we found that flat membrane is transformed into Λ-shaped, Ω-shaped, and O-shaped vesicles via invagination, Λ-base constriction, and Ω-pore constriction, respectively. Surprisingly, endocytic vesicle formation is predominantly from not flat-membrane-to-round-vesicle transformation but calcium-triggered and dynamin-mediated closure of (1) Ω profiles formed before depolarization and (2) fusion pores (called kiss-and-run). Varying calcium influxes control the speed, number, and vesicle size of these pore closures, resulting in speed-specific slow (more than ∼6 s), fast (less than ∼6 s), or ultrafast (<0.6 s) endocytosis, amount-specific compensatory endocytosis (endocytosis = exocytosis) or overshoot endocytosis (endocytosis > exocytosis), and size-specific bulk endocytosis. These findings reveal major membrane transformation mechanisms underlying endocytosis, diverse endocytic modes, and exocytosis-endocytosis coupling, calling for correction of the half-a-century concept that the flat-to-round transformation predominantly mediates endocytosis after physiological stimulation.


Assuntos
Células Cromafins/fisiologia , Células Cromafins/ultraestrutura , Endocitose/fisiologia , Células Neuroendócrinas/fisiologia , Células Neuroendócrinas/ultraestrutura , Animais , Sinalização do Cálcio , Bovinos , Fusão Celular , Membrana Celular/fisiologia , Membrana Celular/ultraestrutura , Sistemas Computacionais , Dinaminas/fisiologia , Exocitose/fisiologia , Fusão de Membrana , Cultura Primária de Células , Vesículas Sinápticas/metabolismo
18.
Nat Commun ; 12(1): 4990, 2021 08 17.
Artigo em Inglês | MEDLINE | ID: mdl-34404808

RESUMO

Cells can expand their plasma membrane laterally by unfolding membrane undulations and by exocytosis. Here, we describe a third mechanism involving invaginations held shut by the membrane adapter, dynamin. Compartments open when Ca activates the lipid scramblase, TMEM16F, anionic phospholipids escape from the cytoplasmic monolayer in exchange for neutral lipids, and dynamins relax. Deletion of TMEM16F or dynamins blocks expansion, with loss of dynamin expression generating a maximally expanded basal plasma membrane state. Re-expression of dynamin2 or its GTPase-inactivated mutant, but not a lipid binding mutant, regenerates reserve compartments and rescues expansion. Dynamin2-GFP fusion proteins form punctae that rapidly dissipate from these compartments during TMEM16F activation. Newly exposed compartments extend deeply into the cytoplasm, lack numerous organellar markers, and remain closure-competent for many seconds. Without Ca, compartments open slowly when dynamins are sequestered by cytoplasmic dynamin antibodies or when scrambling is mimicked by neutralizing anionic phospholipids and supplementing neutral lipids. Activation of Ca-permeable mechanosensitive channels via cell swelling or channel agonists opens the compartments in parallel with phospholipid scrambling. Thus, dynamins and TMEM16F control large plasma membrane reserves that open in response to lateral membrane stress and Ca influx.


Assuntos
Anoctaminas/metabolismo , Membrana Celular/metabolismo , Dinaminas/metabolismo , Proteínas de Transferência de Fosfolipídeos/metabolismo , Anoctaminas/genética , Cálcio/metabolismo , Citoplasma , Técnicas de Inativação de Genes , Células HEK293 , Humanos , Membranas/metabolismo , Proteínas de Transferência de Fosfolipídeos/genética , Fosfolipídeos/metabolismo
19.
Cells ; 10(6)2021 06 03.
Artigo em Inglês | MEDLINE | ID: mdl-34204906

RESUMO

High glucose (HG)-induced Drp1 overexpression contributes to mitochondrial dysfunction and promotes apoptosis in retinal endothelial cells. However, it is unknown whether inhibiting Drp1 overexpression protects against the development of retinal vascular cell loss in diabetes. To investigate whether reduced Drp1 level is protective against diabetes-induced retinal vascular lesions, four groups of mice: wild type (WT) control mice, streptozotocin (STZ)-induced diabetic mice, Drp1+/- mice, and STZ-induced diabetic Drp1+/- mice were examined after 16 weeks of diabetes. Western Blot analysis indicated a significant increase in Drp1 expression in the diabetic retinas compared to those of WT mice; retinas of diabetic Drp1+/- mice showed reduced Drp1 level compared to those of diabetic mice. A significant increase in the number of acellular capillaries (AC) and pericyte loss (PL) was observed in the retinas of diabetic mice compared to those of the WT control mice. Importantly, a significant decrease in the number of AC and PL was observed in retinas of diabetic Drp1+/- mice compared to those of diabetic mice concomitant with increased expression of pro-apoptotic genes, Bax, cleaved PARP, and increased cleaved caspase-3 activity. Preventing diabetes-induced Drp1 overexpression may have protective effects against the development of vascular lesions, characteristic of diabetic retinopathy.


Assuntos
Diabetes Mellitus Experimental , Retinopatia Diabética , Dinaminas , Vasos Retinianos/metabolismo , Animais , Diabetes Mellitus Experimental/genética , Diabetes Mellitus Experimental/metabolismo , Retinopatia Diabética/genética , Retinopatia Diabética/metabolismo , Retinopatia Diabética/prevenção & controle , Dinaminas/genética , Dinaminas/metabolismo , Feminino , Masculino , Camundongos , Camundongos Mutantes
20.
J Physiol ; 599(17): 4045-4063, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34269418

RESUMO

KEY POINTS: The maintenance of mitochondrial integrity is critical for skeletal muscle health. Mitochondrial dynamics play key roles in mitochondrial quality control; however, the exact role that mitochondrial fission plays in the muscle ageing process remains unclear. Here we report that both Drp1 knockdown and Drp1 overexpression late in life in mice is detrimental to skeletal muscle function and mitochondrial health. Drp1 knockdown in 18-month-old mice resulted in severe skeletal muscle atrophy, mitochondrial dysfunction, muscle degeneration/regeneration, oxidative stress and impaired autophagy. Overexpressing Drp1 in 18-month-old mice resulted in mild skeletal muscle atrophy and decreased mitochondrial quality. Our data indicate that silencing or overexpressing Drp1 late in life is detrimental to skeletal muscle integrity. We conclude that modulating Drp1 expression is unlikely to be a viable approach to counter the muscle ageing process. ABSTRACT: Sarcopenia, the ageing-related loss of skeletal muscle mass and function, is a debilitating process negatively impacting the quality of life of afflicted individuals. Although the mechanisms underlying sarcopenia are still only partly understood, impairments in mitochondrial dynamics, and specifically mitochondrial fission, have been proposed as an underlying mechanism. Importantly, conflicting data exist in the field and both excessive and insufficient mitochondrial fission were proposed to contribute to sarcopenia. In Drosophila melanogaster, enhancing mitochondrial fission in midlife through overexpression of dynamin-1-like protein (Drp1) extended lifespan and attenuated several key hallmarks of muscle ageing. Whether a similar outcome of Drp1 overexpression is observed in mammalian muscles remains unknown. In this study, we investigated the impact of knocking down and overexpressing Drp1 protein for 4 months in skeletal muscles of late middle-aged (18 months) mice using intra-muscular injections of adeno-associated viruses expressing shRNA targeting Drp1 or full Drp1 cDNA. We report that knocking down Drp1 expression late in life triggers severe muscle atrophy, mitochondrial dysfunctions, degeneration/regeneration, oxidative stress and impaired autophagy. Drp1 overexpression late in life triggered mild muscle atrophy and decreased mitochondrial quality. Taken altogether, our results indicate that both overexpression and silencing of Drp1 in late middle-aged mice negatively impact skeletal muscle mass and mitochondrial health. These data suggest that Drp1 content must remain within a narrow physiological range to preserve muscle and mitochondrial integrity during ageing. Altering Drp1 expression is therefore unlikely to be a viable target to counter sarcopenia.


Assuntos
Drosophila melanogaster , Dinâmica Mitocondrial , Animais , Proteínas do Citoesqueleto/metabolismo , Drosophila melanogaster/metabolismo , Dinaminas/genética , Dinaminas/metabolismo , Proteínas de Ligação ao GTP , Camundongos , Mitocôndrias/metabolismo , Músculo Esquelético/metabolismo , Qualidade de Vida
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