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1.
Cancer Med ; 13(6): e7108, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38523554

RESUMO

BACKGROUND: The incidence of pancreatic cancer (PC) is higher in diabetic patients due to disturbances in glucose and lipid metabolism caused by insulin resistance (IR). However, the effect of diabetes as well as IR on the prognosis of PC patients remains inconclusive. Our study aims to assess the impact of IR on the prognosis of PC patients with diabetes. METHODS: We conducted a retrospective analysis of 172 PC patients with diabetes in our institute from 2015 to 2021. Prognostic assessment was performed using univariate/multifactorial analysis and survival analysis. The predictive efficacy of metabolic indices was compared using receiver operator characteristic (ROC) curve analysis. RESULTS: One hundred twenty-one of 172 patients died during follow-up, with a median follow-up of 477 days and a median overall survival (OS) of 270 days. Survival analysis showed a significant difference in OS by IR related parameters, which were triglyceride-glucose index (TyG), triglyceride-glucose index-body mass index (TyG-BMI), and triglyceride/high-density lipoprotein cholesterol ratio (TG/HDL-c). The ROC curve indicated that TyG, TyG-BMI, and TG/HDL-c had prognostic efficacy for PC with diabetes. We next optimized TyG-BMI and obtained a new parameter, namely glucose-lipid metabolism index (GLMI), and the patients were classified into GLMI low group and high group based on the calculated cutoff value. The GLMI high group had higher TyG, TyG-BMI, TyG/HDL-c, BMI, TG, total cholesterol (TC), TC/HDL-c, fasting plasma glucose, CA199, and more advanced tumor stage compared to low group. Univariate and multivariate analyses showed that GLMI was an independent prognostic factor. Furthermore, the patients of GLMI high group had worse OS compared to low group and the ROC curves showed GLMI had better predictive ability than TyG and TyG-BMI. CONCLUSIONS: IR is associated with the outcome of PC patients with diabetes and higher level of IR indicates worse prognosis. GLMI has a good predictive value for PC with diabetes.


Assuntos
Diabetes Mellitus Tipo 2 , Resistência à Insulina , Neoplasias Pancreáticas , Humanos , Glucose , Prognóstico , Glicemia/metabolismo , Estudos Retrospectivos , Biomarcadores , Triglicerídeos , Neoplasias Pancreáticas/complicações , Neoplasias Pancreáticas/diagnóstico , Colesterol
2.
J Chem Phys ; 160(5)2024 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-38341711

RESUMO

Topological regulation of DNA by topoisomerases in cells is very crucial for life. We propose a coarse-grained model to study the catenation process of double-stranded DNA (dsDNA) rings regulated by topoisomerase II (TOP2) and provide a computational method to characterize the topological structures of the Olympic gels obtained. The function of TOP2 in the catenation of dsDNA rings is implicitly fulfilled by operating the length of a stretchable catch bond in the dsDNA ring. After the catenation reaction of initially noncatenated dsDNA rings in the solution, the Olympic gel is obtained and the interlocked topology of the dsDNA rings can be characterized by a computational method derived from the HOMFLY polynomial, based on which the catenation degree and the complexity of catenation are quantified. Detailed dependence of the catenation degree and the complexity of the catenated topology on key parameters, including the size of the transient broken gap and the duration time of the break on the dsDNA ring during operation by TOP2, the initial molar ratio of TOP2 to the dsDNA rings, and the reaction temperature, has been investigated.


Assuntos
DNA Topoisomerases Tipo II , DNA
3.
Transl Oncol ; 41: 101877, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38262107

RESUMO

Pancreatic ductal adenocarcinoma (PDAC) is a highly lethal malignancy with an extremely poor prognosis. Cancer stem cells (CSCs) are considered to be responsible for the poor survival, recurrence and therapy resistance of PDAC. Ferroptosis plays a crucial role in the sustain and survival of CSCs. Here, we employed a rigorous evaluation of multiple datasets to identify a novel stemness-based and ferroptosis-related genes (SFRGs) signature to access the potential prognostic application. This work we retrieved RNA-sequencing and clinical annotation data from the TCGA, ICGC, GTEx and GEO database, and acquired 26 stem cell gene sets and 259 ferroptosis genes from StemChecker database and FerrDb database, respectively. Based on consensus clustering and ssGSEA analysis, we identified two expression patterns of CSCs traits (C1 and C2). Then, WGCNA analysis was implemented to screen out hub module genes correlated with stemness. Furthermore, differential expression analysis, Pearson correlation analysis, and the Least absolute shrinkage and selection operator (LASSO) and Cox regression were performed to identify the SFRGs and to construct model. In addition, the differences in prognosis, tumor microenvironment (TME) components and therapy responses were evaluated between two risk groups. Finally, we verified the most influential marker ARNTL2 experimentally by western blot, qRT-PCR, sphere formation assay, mitoscreen assay, intracellular iron concentration determination and MDA determination assays. In conclusion, we developed a stemness-based and ferroptosis-related prognostic model, which could help predict overall survival for PDAC patients. Targeting ferroptosis may be a promising therapeutic strategy to inhibit PDAC progression by suppressing CSCs.

4.
Front Med (Lausanne) ; 10: 1256176, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-38076257

RESUMO

Neuroendocrine tumors (NETs) are a heterogeneous group of tumors originating from peptide-producing neurons and neuroendocrine cells. The liver is the most common site of metastasis for NETs, while primary hepatic neuroendocrine tumors (PHNETs) are exceedingly rare. While somatostatin receptor scintigraphy (SRS) has demonstrated superior efficacy compared to [18F]FDG PET imaging in the diagnosis of neuroendocrine tumors, [18F]AlF-NOTA-Octreotide ([18F]AlF-OC) PET/CT also exhibits specific advantages over SRS. This article presents a case study of a patient with a liver mass who underwent sequential [18F]FDG and [18F]AlF-OC PET/CT scans, ruling out hepatocellular carcinoma and confirming the diagnosis of PHNETs. Subsequently, the patient underwent surgical treatment. From another perspective, [18F]AlF-OC exhibits distinct advantages. The postoperative pathology revealed a PHNETs, which further emphasizes its clinical rarity.

5.
Front Pharmacol ; 14: 1284610, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-38084101

RESUMO

Genome-wide clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR associated nuclease 9 (Cas9) screening is a simple screening method for locating loci under specific conditions, and it has been utilized in tumor drug resistance research for finding potential drug resistance-associated genes. This screening strategy has significant implications for further treatment of malignancies with acquired drug resistance. In recent years, studies involving genome-wide CRISPR/Cas9 screening have gradually increased. Here we review the recent application of genome-wide CRISPR/Cas9 screening for drug resistance, involving mitogen-activated protein kinase (MAPK) pathway inhibitors, poly (ADP-ribose) polymerase inhibitors (PARPi), alkylating agents, mitotic inhibitors, antimetabolites, immune checkpoint inhibitors (ICIs), and cyclin-dependent kinase inhibitors (CDKI). We summarize drug resistance pathways such as the KEAP1/Nrf2 pathway MAPK pathway, and NF-κB pathway. Also, we analyze the limitations and conditions for the application of genome-wide CRISPR/Cas9 screening techniques.

6.
BMC Surg ; 23(1): 339, 2023 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-37950192

RESUMO

BACKGROUND: Blumgart pancreaticojejunostomy (PJ) was shown to be an effective method for pancreaticojejunostomy in open pancreaticoduodenectomy. But the original Blumgart method is involved in complicated and interrupted sutures, which may not be suitable for the laparoscopic approach. In this study, we introduced a simplified Blumgart method for laparoscopic pancreaticojejunostomy. METHODS: We retrospectively reviewed 90 cases of pancreaticoduodenectomy in our institute from 2019 to 2022. Among them, 32 patients received LPD with simplified Blumgart PJ, while 29 received LPD with traditional duct-to-mucosal anastomosis (the Cattel-Warren technique) and 29 received OPD with traditional duct-to-mucosal anastomosis. And the time length for PJ and the surgical outcome were compared in these three groups. RESULTS: The simplified Blumgart pancreaticojejunostomy was accomplished in all 32 cases with no conversion to open surgery due to improper sutures. And the time length for laparoscopic simplified Blumgart pancreaticojejunostomy was 26 ± 8.4 min, which was shorter than laparoscopic traditional ductal to mucosa pancreaticojejunostomy (39 ± 13.7 min). Importantly, the overall incidence for POPF and grade B&C POPF rate in the laparoscopic simplified Blumgart method group were 25% and 9.38% respectively, which were lower than the other two groups. Moreover, we performed univariate analysis and multivariate analysis and found soft pancreas, pancreatic ductal diameter < = 3 mm and intraoperative blood loss were independent risk factors for POPF after PD. CONCLUSION: Our data suggest that the simplified Blumgart method is a feasible and reliable method for laparoscopic PJ which deserves further validation.


Assuntos
Laparoscopia , Pancreaticojejunostomia , Humanos , Pancreaticojejunostomia/métodos , Pancreaticoduodenectomia/métodos , Estudos Retrospectivos , Fístula Pancreática/etiologia , Complicações Pós-Operatórias/etiologia , Anastomose Cirúrgica/métodos , Laparoscopia/métodos
7.
Front Oncol ; 13: 1251561, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37736551

RESUMO

The ability of cancer stem cells (CSCs) to self-renew, differentiate, and generate new tumors is a significant contributor to drug resistance, relapse, and metastasis. Therefore, the targeting of CSCs for treatment is particularly important. Recent studies have demonstrated that CSCs are more susceptible to ferroptosis than non-CSCs, indicating that this could be an effective strategy for treating tumors. Ferroptosis is a type of programmed cell death that results from the accumulation of lipid peroxides caused by intracellular iron-mediated processes. CSCs exhibit different molecular characteristics related to iron and lipid metabolism. This study reviews the alterations in iron metabolism, lipid peroxidation, and lipid peroxide scavenging in CSCs, their impact on ferroptosis, and the regulatory mechanisms underlying iron metabolism and ferroptosis. Potential treatment strategies and novel compounds targeting CSC by inducing ferroptosis are also discussed.

8.
Front Immunol ; 14: 1230261, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37671157

RESUMO

Intrahepatic cholangiocarcinoma (ICC) is one of the most common invasive malignant tumors, with a 5-year survival rate of less than 5%. Currently, radical surgical resection is the preferred treatment for ICC. However, most patients are only diagnosed at an advanced stage and are therefore not eligible for surgery. Herein, we present a case of advanced ICC in which radical surgery was not possible due to tumor invasion of the second porta hepatis and right hepatic artery. Six treatment cycles with a gemcitabine and oxaliplatin (GEMOX) regimen combined with camrelizumab immunotherapy achieved a partial response and successful tumor conversion, as tumor invasion of the second porta hepatis and right hepatic artery was no longer evident. The patient subsequently underwent successful radical surgical resection, including hepatectomy, caudate lobe resection, and cholecystectomy combined with lymph node dissection. Cases of patients with advanced ICC undergoing surgical resection after combined immunotherapy and chemotherapy are rare. The GEMOX regimen combined with camrelizumab demonstrated favorable antitumor efficacy and safety, suggesting that it might be a potential feasible and safe conversion therapy strategy for patients with advanced ICC.


Assuntos
Neoplasias dos Ductos Biliares , Colangiocarcinoma , Humanos , Gencitabina , Oxaliplatina , Ductos Biliares Intra-Hepáticos
9.
Front Oncol ; 13: 1155233, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37305571

RESUMO

Pancreatic cancer is a common type of cancer that is treated using surgery or chemotherapy. However, for patients who cannot have surgery, the treatment options are limited and have a low success rate. We report a case of a patient with locally advanced pancreatic cancer who was unable to have surgery due to a tumor that had invaded the coeliac axis and portal vein. However, after receiving chemotherapy with gemcitabine plus nab-paclitaxel(GEM-NabP), the patient achieved complete remission, and a PET-CT scan confirmed that the tumor had disappeared. Eventually, the patient underwent radical surgery with distal pancreatectomy with splenectomy, and the treatment was successful. This case is rare, and there are few reports of complete remission after chemotherapy for pancreatic cancer. This article reviews the relevant literature and guides future clinical practice.

10.
ACS Appl Mater Interfaces ; 15(25): 30717-30726, 2023 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-37335904

RESUMO

The development of new polymer-based room-temperature phosphorescence materials is of great significance. By a special molecule design and a set of feasible property-enhancing strategies, coumarin derivatives (CMDs, Ma-Mf) were doped into polyvinyl alcohol (PVA), polyacrylamide (PAM), corn starch, and polyacrylonitrile (PAN) as information anti-counterfeiting. CMDs-doped PVA and CMDs-doped corn starch films showed long-lived phosphorescence emissions up to 1246 ms (Ma-PVA) and 697 ms (Ma-corn starch), reaching over 10 s afterglow under naked eye observation under ambient conditions. Significantly, CMDs-doped PAM films can display long-lived phosphorescence emissions in a wide temperature range (100-430 K). For example, the Me-PAM film has a phosphorescence lifetime of 16 ms at 430 K. The use of PAM with the strong polarity and rigidity has expanded the temperature range of long-life polymer-based phosphorescent materials. The present long-lived phosphorescent systems provide the possibility for developing new polymer-based organic afterglow materials with robust phosphorescence.

11.
Polymers (Basel) ; 15(9)2023 Apr 24.
Artigo em Inglês | MEDLINE | ID: mdl-37177174

RESUMO

The use of biodegradable plastics is gradually increasing, but its expensive cost limits promotion. In this study, poly(butylene adipate-co-terephthalate)/thermoplastic hydroxypropyl starch reinforced with nano-silica (PBAT/TPHSg-SiO2) composite films with high hydroxypropyl starch content were prepared in a two-step process. The effect of reinforced thermoplastic hydroxypropyl starch on the mechanical, thermal, processing properties, and micromorphology of the composite films was investigated. The results showed that the tensile strength of the composite films was significantly improved by the addition of nano-silica, with 35% increase in horizontal tensile strength and 21% increase in vertical tensile strength after the addition of 4 phr of nano-silica. When the content of thermoplastic hydroxypropyl starch reinforced with nano-silica (TPHSg-4SiO2) is 40%, the horizontal and vertical tensile strengths of the films are 9.82 and 12.09 MPa, respectively, and the elongation at break of the films is over 500%. Electron micrographs show that TPHSg-4SiO2 is better homogeneously dispersed in the PBAT and exhibits a bi-continuous phase structure at a TPHSg-4SiO2 content of 40%. In this study, the blowing PBAT/TPHSg-4SiO2 composite films effectively reduce the cost and still show better mechanical properties, which are suitable for packaging applications.

12.
IEEE Trans Pattern Anal Mach Intell ; 45(1): 247-263, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34995183

RESUMO

Instance image retrieval could greatly benefit from discovering objects in the image dataset. This not only helps produce more reliable feature representation but also better informs users by delineating query-matched object regions. However, object classes are usually not predefined in a retrieval dataset and class label information is generally unavailable in image retrieval. This situation makes object discovery a challenging task. To address this, we propose a novel dataset-driven unsupervised object discovery framework. By utilizing deep feature representation and weakly-supervised object detection, we explore supervisory information from within an image dataset, construct class-wise object detectors, and assign multiple detectors to each image for detection. To efficiently construct object detectors for large image datasets, we propose a novel "base-detector repository" and derive a fast way to generate the base detectors. In addition, the whole framework is designed to work in a self-boosting manner to iteratively refine object discovery. Compared with existing unsupervised object detection methods, our framework produces more accurate object discovery results. Different from supervised detection, we need neither manual annotation nor auxiliary datasets to train object detectors. Experimental study demonstrates the effectiveness of the proposed framework and the improved performance for region-based instance image retrieval.

13.
J Oncol ; 2022: 1463316, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36276283

RESUMO

Medical technology has become more and more sophisticated recently, which, however, fails to contribute to a better prognosis for patients suffering advanced gastric cancer (GC). Hence, new biomarkers specific to GC diagnosis and prognosis shall be identified urgently. This study screened differentially expressed genes (DEGs) between 375 GC samples and 32 paracancer tissue samples from TCGA datasets. The expression of Collagen type X alpha 1 (COL10A1) in GC was analyzed. The chi-square test assisted in analyzing the relevance of COL10A1 to the clinicopathologic characteristics. The Kaplan-Meier method helped to assess the survival curves and log-rank tests assisted in the examination of the differences. The Cox proportional hazard regression model served for analyzing the risk factors for GC. Then, we developed a nomogram that contained the COL10A1 expression and clinical information. Finally, how COL10A1 expression was associated with the immune infiltration was also evaluated. In this study, 7179 upregulated and 3771 downregulated genes were identified. Among them, COL10A1 expression was distinctly increased in GC specimens compared with nontumor specimens. High COL10A1 expression exhibited an obvious relation to tumor T and pathologic stage. ROC assays confirmed the diagnostic value of COL10A1 expression in screening GC samples from normal samples. Survival data displayed that patients with high COL10A1 expression exhibited a shorter OS and DSS than those with low COL10A1 expression. We obtained a predictive nomogram, which could better predict the COL10A1 expression by virtue of discrimination and calibration. The prognostic value of COL10A1 expression was further confirmed in GSE84426 datasets. Immune assays revealed that COL10A1 expression was associated with tumor-filtrating immune cells, like CD8 T cells, cytotoxic cells, DC, eosinophils, iDC, macrophages, mast cells, NK CD56dim cells, NK cells, pDC, T helper cells, Tem, Th1 cells, Th17 cells, and Treg. Overall, we firstly proved that COL10A1 may be a novel and valuable prognostic and diagnostic factor for GC patients. In addition, COL10A1 has potential to be an immune indicator in GC.

14.
Plant Cell Rep ; 41(12): 2379-2391, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36208306

RESUMO

KEY MESSAGE: Within a QTL, the genetic recombination and interactions among five and two functional variations at MdbHLH25 and MdWDR5A caused much complicated phenotype segregation in apple FFR and FCR. The storability of climacteric fruit like apple is a quantitative trait. We previously identified 62 quantitative trait loci (QTLs) associating flesh firmness retainability (FFR) and flesh crispness retainability (FCR), but only a few functional genetic variations were identified and validated. The genetic variation network controlling fruit storability is far to be understood and diagnostic markers are needed for molecular breeding. We previously identified overlapped QTLs F16.1/H16.2 for FFR and FCR using an F1 population derived from 'Zisai Pearl' × 'Red Fuji'. In this study, five and two single-nucleotide polymorphisms (SNPs) were identified on the candidate genes MdbHLH25 and MdWDR5A within the QTL region. The SNP1 A allele at MdbHLH25 promoter reduced the expression and SNP2 T allele and/or SNP4/5 GT alleles at the exons attenuated the function of MdbHLH25 by downregulating the expression of the target genes MdACS1, which in turn led to a reduction in ethylene production and maintenance of higher flesh crispness. The SNPs did not alter the protein-protein interaction between MdbHLH25 and MdWDR5A. The joint effect of SNP genotype combinations by the SNPs on MdbHLH25 (SNP1, SNP2, and SNP4) and MdWDR5A (SNPi and SNPii) led to a much broad spectrum of phenotypic segregation in FFR and FCR. Together, the dissection of these genetic variations contributes to understanding the complicated effects of a QTL and provides good potential for marker development in molecular breeding.


Assuntos
Malus , Locos de Características Quantitativas , Locos de Características Quantitativas/genética , Malus/genética , Mapeamento Cromossômico , Fenótipo , Polimorfismo de Nucleotídeo Único/genética
15.
J Nanosci Nanotechnol ; 16(6): 5546-52, 2016 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-27427595

RESUMO

In this study, three engineered metal oxide nanoparticles (NPs) with similar size but significantly different solubility were used to study the cellular uptake, toxicity and immune activation of Raw 264.7 cells. Commercially available TiO2, Fe2O3 and ZnO NPs were used in this study. Although the size of three pristine NPs are different, all three NPs showed similar aggregation state (250-300 nm) and surface zeta potential (-10 mV) in serum containing cell culture medium due to the surface adsorption of proteins. The ZnO NPs release high concentration of Zn2+ in cell culture medium, especially at lower pH mimicking endosomal environment. In contrast, Fe2O3 NPs have limited solubility and TiO2 NPs only release very low concentration of ions. The cellular loading of the TiO2 and Fe2O3 NPs increased with the incubation time and Raw264.7 cells ingested more Fe2O3 NPs than TiO2 NPs. In general, the TiO2 and Fe2O3 NPs did not have obvious cytotoxicity. However, the TiO2 and Fe2O3 NPs can induce strong immune response of Raw264.7 cells, leading to higher expression of TNF-α and IL-6, especially at relatively longer incubation time. ZnO NPs were rapidly ingested into cells and release Zn2+, inducing significant cell death. They also can enhance the expression of TNF-a and IL-6 of Raw264.7 cells at beginning, but reduced significantly at longer incubation time due to cell death.


Assuntos
Leucócitos/efeitos dos fármacos , Metais Pesados/química , Nanopartículas/química , Óxidos/química , Óxidos/toxicidade , Animais , Transporte Biológico , Adesão Celular/efeitos dos fármacos , Movimento Celular/efeitos dos fármacos , Interleucina-6/metabolismo , Leucócitos/citologia , Leucócitos/imunologia , Leucócitos/metabolismo , Camundongos , Óxidos/metabolismo , Células RAW 264.7 , Solubilidade , Fator de Necrose Tumoral alfa/metabolismo
16.
Infect Immun ; 81(6): 1905-14, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23509143

RESUMO

Obesity is associated with a chronic low-grade inflammation characterized by increased levels of proinflammatory cytokines that are implicated in disrupted metabolic homeostasis. Parasitic nematode infection induces a polarized Th2 cytokine response and has been explored to treat autoimmune diseases. We investigated the effects of nematode infection against obesity and the associated metabolic dysfunction. Infection of RIP2-Opa1KO mice or C57BL/6 mice fed a high-fat diet (HFD) with Nippostrongylus brasiliensis decreased weight gain and was associated with improved glucose metabolism. Infection of obese mice fed the HFD reduced body weight and adipose tissue mass, ameliorated hepatic steatosis associated with a decreased expression of key lipogenic enzymes/mediators, and improved glucose metabolism, accompanied by changes in the profile of metabolic hormones. The infection resulted in a phenotypic change in adipose tissue macrophages that was characterized by upregulation of alternative activation markers. Interleukin-13 (IL-13) activation of the STAT6 signaling pathway was required for the infection-induced attenuation of steatosis but not for improved glucose metabolism, whereas weight loss was attributed to both IL-13/STAT6-dependent and -independent mechanisms. Parasitic nematode infection has both preventive and therapeutic effects against the development of obesity and associated features of metabolic dysfunction in mice.


Assuntos
Nippostrongylus , Obesidade/parasitologia , Infecções por Strongylida/patologia , Tecido Adiposo , Animais , Glicemia , Modelos Animais de Doenças , Metabolismo Energético , GTP Fosfo-Hidrolases/genética , GTP Fosfo-Hidrolases/metabolismo , Ácido Glucárico/metabolismo , Homeostase , Interleucina-13/genética , Interleucina-13/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Proteína Serina-Treonina Quinase 2 de Interação com Receptor , Proteína Serina-Treonina Quinases de Interação com Receptores/genética , Proteína Serina-Treonina Quinases de Interação com Receptores/metabolismo , Fator de Transcrição STAT6/genética , Fator de Transcrição STAT6/metabolismo , Infecções por Strongylida/metabolismo , Aumento de Peso
17.
Autophagy ; 8(10): 1531-3, 2012 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-22732519

RESUMO

Mitochondrial division is mediated by the conserved dynamin-related GTPase DNM1L/DRP1. DNM1L assembles onto the surface of mitochondria and constricts this tubular organelle. Alterations in mitochondrial division are linked to many neurodegenerative diseases. However, the in vivo function of mitochondrial division is poorly understood. In our recent paper, we studied the physiological role of mitochondrial division in postmitotic neurons using the cre-loxP system. We found that the loss of DNM1L resulted in increased oxidative damage in mitochondria, impaired respiration and neurodegeneration in postmitotic neurons. Suggesting a decrease in mitochondrial turnover, mitophagy-related proteins such as LC3, SQSTM1/p62 and ubiqutin accumulated in division-defective mitochondria. These findings suggest that mitochondrial division functions as an important quality control mechanism that suppresses oxidative damage and neurodegeneration in vivo.


Assuntos
Mitocôndrias/metabolismo , Degeneração Neural/patologia , Animais , Morte Celular , Dinaminas/metabolismo , Embrião de Mamíferos/citologia , Fibroblastos/metabolismo , Humanos , Camundongos , Camundongos Knockout , Degeneração Neural/metabolismo , Neurônios/metabolismo , Neurônios/patologia , Estresse Oxidativo , Células de Purkinje/metabolismo , Células de Purkinje/patologia
18.
J Cell Biol ; 197(4): 535-51, 2012 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-22564413

RESUMO

Mitochondria divide and fuse continuously, and the balance between these two processes regulates mitochondrial shape. Alterations in mitochondrial dynamics are associated with neurodegenerative diseases. Here we investigate the physiological and cellular functions of mitochondrial division in postmitotic neurons using in vivo and in vitro gene knockout for the mitochondrial division protein Drp1. When mouse Drp1 was deleted in postmitotic Purkinje cells in the cerebellum, mitochondrial tubules elongated due to excess fusion, became large spheres due to oxidative damage, accumulated ubiquitin and mitophagy markers, and lost respiratory function, leading to neurodegeneration. Ubiquitination of mitochondria was independent of the E3 ubiquitin ligase parkin in Purkinje cells lacking Drp1. Treatment with antioxidants rescued mitochondrial swelling and cell death in Drp1KO Purkinje cells. Moreover, hydrogen peroxide converted elongated tubules into large spheres in Drp1KO fibroblasts. Our findings suggest that mitochondrial division serves as a quality control mechanism to suppress oxidative damage and thus promote neuronal survival.


Assuntos
Sobrevivência Celular , Mitocôndrias/metabolismo , Mitose , Neurônios/citologia , Animais , Dinaminas/genética , Dinaminas/metabolismo , Camundongos , Camundongos Endogâmicos , Proteínas Mitocondriais/genética , Proteínas Mitocondriais/metabolismo , Neurônios/metabolismo , Oxirredução , Células de Purkinje/metabolismo
19.
Mol Biol Cell ; 22(13): 2235-45, 2011 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-21551073

RESUMO

Previous studies using in vitro cell culture systems have shown the role of the dynamin-related GTPase Opa1 in apoptosis prevention and mitochondrial DNA (mtDNA) maintenance. However, it remains to be tested whether these functions of Opa1 are physiologically important in vivo in mammals. Here, using the Cre-loxP system, we deleted mouse Opa1 in pancreatic beta cells, in which glucose-stimulated ATP production in mitochondria plays a key role in insulin secretion. Beta cells lacking Opa1 maintained normal copy numbers of mtDNA; however, the amount and activity of electron transport chain complex IV were significantly decreased, leading to impaired glucose-stimulated ATP production and insulin secretion. In addition, in Opa1-null beta cells, cell proliferation was impaired, whereas apoptosis was not promoted. Consequently, mice lacking Opa1 in beta cells develop hyperglycemia. The data suggest that the function of Opa1 in the maintenance of the electron transport chain is physiologically relevant in beta cells.


Assuntos
Trifosfato de Adenosina/biossíntese , Dinaminas/metabolismo , GTP Fosfo-Hidrolases/metabolismo , Glucose/metabolismo , Células Secretoras de Insulina/metabolismo , Trifosfato de Adenosina/metabolismo , Animais , Apoptose/fisiologia , Proliferação de Células , DNA Mitocondrial/metabolismo , Complexo IV da Cadeia de Transporte de Elétrons/metabolismo , GTP Fosfo-Hidrolases/deficiência , GTP Fosfo-Hidrolases/genética , Intolerância à Glucose/metabolismo , Hiperglicemia/metabolismo , Hiperglicemia/patologia , Insulina/metabolismo , Células Secretoras de Insulina/citologia , Células Secretoras de Insulina/enzimologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Mitocôndrias/metabolismo , Proteína Serina-Treonina Quinase 2 de Interação com Receptor , Proteína Serina-Treonina Quinases de Interação com Receptores/metabolismo
20.
Curr Opin Cell Biol ; 23(4): 427-34, 2011 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-21565481

RESUMO

Mitochondrial division has emerged as a key mechanism for this essential organelle to maintain its structural integrity, intracellular distribution, and functional competence. An evolutionarily conserved dynamin-related GTPase, Dnm1p/Drp1, interacts with other proteins to form the core machinery involved in mitochondrial division. We summarize recent progress in understanding how the division machinery assembles onto mitochondria and how mitochondrial division contributes to cellular physiology and human diseases.


Assuntos
GTP Fosfo-Hidrolases/metabolismo , Mitocôndrias/fisiologia , Animais , Apoptose , Dinaminas/metabolismo , GTP Fosfo-Hidrolases/química , Humanos , Mitocôndrias/enzimologia , Proteínas Mitocondriais/metabolismo
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