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1.
Proc Natl Acad Sci U S A ; 119(14): e2122217119, 2022 04 05.
Article in English | MEDLINE | ID: mdl-35344434

ABSTRACT

SignificanceA clear mechanistic understanding of metformin's antidiabetic effects is lacking. This is because suprapharmacological concentrations of metformin have been used in most studies. Using mouse models and human primary hepatocytes, we show that metformin, at clinically relevant doses, suppresses hepatic glucose production by activating a conserved regulatory pathway encompassing let-7, TET3, and a fetal isoform of hepatocyte nuclear factor 4 alpha (HNF4α). We demonstrate that metformin no longer has potent antidiabetic actions in a liver-specific let-7 loss-of-function mouse model and that hepatic delivery of let-7 ameliorates hyperglycemia and improves glucose homeostasis. Our results thus reveal an important role of the hepatic let-7/TET3/HNF4α axis in mediating the therapeutic effects of metformin and suggest that targeting this axis may be a potential therapeutic for diabetes.


Subject(s)
Hyperglycemia , Metformin , Animals , Disease Models, Animal , Glucose/metabolism , Hepatocytes/metabolism , Hyperglycemia/metabolism , Hypoglycemic Agents/pharmacology , Hypoglycemic Agents/therapeutic use , Liver/metabolism , Metformin/therapeutic use , Mice
2.
Cardiology ; 148(6): 581-592, 2023.
Article in English | MEDLINE | ID: mdl-37459844

ABSTRACT

BACKGROUND: Left atrial appendage closure (LAAC) is a safe and effective method for preventing embolic events in patients with non-valvular atrial fibrillation. However, peri-device leaks (PDLs) are sometimes unavoidable. Controversy exists regarding whether PDLs lead to embolic events. OBJECTIVES: This study aimed to explore the association between PDLs and embolic events, including ischaemic stroke, transient ischaemic attacks (TIAs), and systemic embolism (SE). METHODS: We conducted a systematic search of the PubMed, Web of Science, MEDLINE, and Cochrane Library databases for studies published up to September 25, 2022, to compare the rate of ischaemic stroke/TIA/SE between the PDL group and the non-PDL group after LAAC. RESULTS: Thirteen studies comprising 54,405 patients were included in the meta-analysis. The PDL group detected by transoesophageal echocardiography (TEE) had a significantly higher rate of ischaemic stroke/TIA/SE than the non-PDL group (OR: 1.20, 95% CI: 1.08-1.33, p = 0.0009). However, no difference in ischaemic stroke/TIA/SE was found between the PDL and non-PDL subgroups of the cardiac computed tomography angiography (CCTA) group (OR: 1.12, 95% CI: 0.51-2.50, p = 0.77). CCTA and TEE showed different rates of PDL detection, with the CCTA group having a higher rate of PDL detection (p < 0.0001), especially for trivial leaks. CONCLUSIONS: PDL detected by TEE increases the risk of embolic events after LAAC. However, no association was found between PDL and ischaemic stroke/TIA/SE in the CCTA group, which showed a higher rate of PDL detection than TEE, particularly for trivial leaks. In the future, CCTA may be used to explore the relationship between PDL size and ischaemic stroke/TIA/SE.


Subject(s)
Atrial Appendage , Atrial Fibrillation , Brain Ischemia , Embolism , Ischemic Attack, Transient , Ischemic Stroke , Stroke , Humans , Ischemic Attack, Transient/etiology , Left Atrial Appendage Closure , Stroke/etiology , Stroke/prevention & control , Brain Ischemia/etiology , Atrial Fibrillation/etiology , Ischemic Stroke/etiology , Embolism/etiology , Embolism/prevention & control , Atrial Appendage/diagnostic imaging , Atrial Appendage/surgery , Treatment Outcome , Echocardiography, Transesophageal , Cardiac Catheterization/adverse effects
3.
Mol Cell ; 57(4): 721-734, 2015 Feb 19.
Article in English | MEDLINE | ID: mdl-25699712

ABSTRACT

MicroRNAs (miRNAs) regulate the translational potential of their mRNA targets and control many cellular processes. The key step in canonical miRNA biogenesis is the cleavage of the primary transcripts by the nuclear RNase III enzyme Drosha. Emerging evidence suggests that the miRNA biogenic cascade is tightly controlled. However, little is known whether Drosha is regulated. Here, we show that Drosha is targeted by stress. Under stress, p38 MAPK directly phosphorylates Drosha at its N terminus. This reduces its interaction with DiGeorge syndrome critical region gene 8 and promotes its nuclear export and degradation by calpain. This regulatory mechanism mediates stress-induced inhibition of Drosha function. Reduction of Drosha sensitizes cells to stress and increases death. In contrast, increase in Drosha attenuates stress-induced death. These findings reveal a critical regulatory mechanism by which stress engages p38 MAPK pathway to destabilize Drosha and inhibit Drosha-mediated cellular survival.


Subject(s)
Ribonuclease III/physiology , Stress, Physiological , p38 Mitogen-Activated Protein Kinases/physiology , Active Transport, Cell Nucleus , Cell Survival , HEK293 Cells , Humans , Phosphorylation , Proteolysis , RNA-Binding Proteins/genetics , RNA-Binding Proteins/metabolism , RNA-Binding Proteins/physiology , Ribonuclease III/genetics , Ribonuclease III/metabolism , p38 Mitogen-Activated Protein Kinases/genetics , p38 Mitogen-Activated Protein Kinases/metabolism
4.
Nat Methods ; 14(2): 160-166, 2017 02.
Article in English | MEDLINE | ID: mdl-27941784

ABSTRACT

The precise manipulation of microcirculation in mice can facilitate mechanistic studies of brain injury and repair after ischemia, but this manipulation remains a technical challenge, particularly in conscious mice. We developed a technology that uses micromagnets to induce aggregation of magnetic nanoparticles to reversibly occlude blood flow in microvessels. This allowed induction of ischemia in a specific cortical region of conscious mice of any postnatal age, including perinatal and neonatal stages, with precise spatiotemporal control but without surgical intervention of the skull or artery. When combined with longitudinal live-imaging approaches, this technology facilitated the discovery of a feature of the ischemic cascade: selective loss of smooth muscle cells in juveniles but not adults shortly after onset of ischemia and during blood reperfusion.


Subject(s)
Brain Ischemia/chemically induced , Brain Ischemia/physiopathology , Magnetite Nanoparticles/adverse effects , Animals , Brain Ischemia/drug therapy , Cerebral Arteries/drug effects , Cerebral Arteries/physiopathology , Cerebrovascular Circulation/drug effects , Cerebrovascular Circulation/physiology , Disease Models, Animal , HEK293 Cells , Hippocampus/drug effects , Humans , Magnetic Resonance Imaging/methods , Magnetite Nanoparticles/chemistry , Magnetite Nanoparticles/toxicity , Mice, Inbred C57BL , Mice, Transgenic , Microcirculation/drug effects , Microvessels/drug effects , Microvessels/physiopathology
5.
Neurosurg Rev ; 41(3): 891-894, 2018 Jul.
Article in English | MEDLINE | ID: mdl-29572579

ABSTRACT

Giant intrapetrous internal carotid aneurysms (petrous ICA aneurysm) are rare. A giant petrous ICA aneurysm presenting with otorrhagia and coil exposure to the external auditory meatus (EAM) after endovascular treatment has never been documented before. The authors report here a case of successful surgical trapping with bypass intervention of a giant petrous ICA aneurysm presenting with coil exposure after endovascular treatment. A 58-year-old man presented with persistent otorrhagia having been admitted to our hospital because of the recurrence of a giant petrous ICA aneurysm after repeated embolization treatments with coils. An electronic otoscope examination demonstrated that a piece of coil escaped into his right EAM. After multidisciplinary consultation, an extracranial-intracranial (EC-IC) bypass with ICA occlusion and coil removal with a closed EAM filling were performed in stages. The patient recovered quickly without any neurological deficits. A digital subtraction angiography confirmed the absence of the aneurysm and patency of the bypass graft.


Subject(s)
Blood Vessel Prosthesis/adverse effects , Carotid Artery Diseases/surgery , Endovascular Procedures/methods , Intracranial Aneurysm/surgery , Neurosurgical Procedures/methods , Petrous Bone/surgery , Angiography, Digital Subtraction , Blood Vessel Prosthesis Implantation , Ear Canal/diagnostic imaging , Embolization, Therapeutic , Humans , Male , Middle Aged , Recurrence
6.
Sichuan Da Xue Xue Bao Yi Xue Ban ; 49(6): 865-870, 2018 Nov.
Article in Zh | MEDLINE | ID: mdl-32677394

ABSTRACT

OBJECTIVE: To determine the regulatory and molecular mechanism of lncRNA MALAT1 in response to sepsis induced by lipopolysaccharide (LPS) in rats. METHODS: The expressions of lncRNA MALAT1 and miR-146a in U937 cells and peripheral blood samples of the rats with and without LPS-induced sepsis were detected using quantitative real-time reverse transcription PCR (qRT-PCR). The relationship between lncRNA MALAT1 and miR-146a was affirmed through luciferase assay. The expressions of p-P65, P65, TNF-α and iNOS were tested by Western blot. The expressions of TNF-α and iNOS in the lung tissues of the rats were measured by immunohistochemistry. RESULTS: The rats with LPS-induced sepsis had higher expressions of lncRNA MALAT1 in U937 cells than those without sepsis (P<0.001). In comparison with scramble, si-MALAT1 attenuated the expression of lncRNA MALAT1 and increased the expression of miR-146a (P<0.001). MiR-146a was the target of lncRNA MALAT1. si-MALAT1 decreased the p-P65/P65 ratio and and the expressions of TNF-α and iNOS in the rats with LPS-induced sepsis. In contrast, miR-146a inhibitor increased p-P65/P65 ratio and the expressions of TNF-α and iNOS in the rats with LPS-induced septis (P<0.001). Co-transfection with si-MALAT1 attenuated the elevated level of p-P65/P65 ratio and expressions of TNF-α and iNOS resulting from miR-146a inhibitor (P<0.001). LPS and scramble decreased the expression of miR-146a and increased the p-P65/P65 ratio compared with the healthy controls (P<0.01). Compared with scramble, si-MALAT1 increased the expression of miR-146a and attenuated the p-P65/P65 ratio (P<0.01). Higher numbers of TNF-α and iNOS positive cells were found in those with LPS-induced sepsis and those with scramble interventions (P<0.001). Compared with scramble, si-MALAT1 reduced the number of TNF-α and iNOS positive cells (P<0.01). CONCLUSIONS: LncRNA MALAT1 modulates the immunoreaction of rats with LPS -induced sepsis by targeting miR-146a/NF-κB P65.

7.
J Korean Med Sci ; 32(4): 621-627, 2017 Apr.
Article in English | MEDLINE | ID: mdl-28244288

ABSTRACT

Sodium glucose co-transporter 2 (SGLT-2) inhibitors are newly developed but promising medicine for type 2 diabetes. However, patients with a different renal threshold for glucose excretion (RT(G)) may have a different reaction to this medicine. Therefore, the objective of this study was to investigate the characteristics of RT(G) and its impact factors in patients with type 2 diabetes mellitus (T2DM). The clinical and laboratory data of 36 healthy individuals and 168 in-hospital patients with T2DM were collected and analyzed, RT(G) was calculated using blood glucose (BG) measured by dynamic BG monitoring, urinary glucose excretion (UGE) and estimated glomerular filtration rate (eGFR). The characteristics of RT(G) were investigated. The risk factors for high RT(G) were analyzed using non-conditional logistic regression analysis. Our results found that RT(G) of the T2DM group was higher than that of the healthy individuals (P < 0.05); and 22.22% from the healthy individuals group but 58.33% from the T2DM group had high RT(G). Age, duration of diabetes, body mass index (BMI), and homeostasis model assessment insulin resistance index (HOMA-IR) were independently associated with high RT(G) (P < 0.05). Further stratified analysis revealed that RT(G) in T2DM patients increased with age, duration of diabetes, and BMI. In conclusion, RT(G) is increased in patients with T2DM, especially in those with longer diabetic duration, higher BMI, and those who are older. Therefore, these patients may be more sensitive to SGLT-2 inhibitors.


Subject(s)
Diabetes Mellitus, Type 2/pathology , Glucose/metabolism , Kidney/physiopathology , Adult , Aged , Blood Glucose/analysis , Body Mass Index , Case-Control Studies , Cholesterol, LDL , Diabetes Mellitus, Type 2/blood , Female , Glomerular Filtration Rate , Glycated Hemoglobin/analysis , Humans , Insulin Resistance , Logistic Models , Male , Middle Aged , Odds Ratio , Risk Factors
8.
Biomed Environ Sci ; 30(1): 44-51, 2017 Jan.
Article in English | MEDLINE | ID: mdl-28245898

ABSTRACT

OBJECTIVE: To study the effect of glutamate on metabolism, shifts in glycolysis and lactate release in rat astrocytes. METHODS: After 10 days, secondary cultured astrocytes were treated with 1 mmol/L glutamate for 1 h, and the oxygen consumption rates (OCR) and extra cellular acidification rate (ECAR) was analyzed using a Seahorse XF 24 Extracellular Flux Analyzer. Cell viability was then evaluated by MTT assay. Moreover, changes in extracellular lactate concentration induced by glutamate were tested with a lactate detection kit. RESULTS: Compared with the control group, treatment with 1 mmol/L glutamate decreased the astrocytes' maximal respiration and spare respiratory capacity but increased their glycolytic capacity and glycolytic reserve. Further analysis found that 1-h treatment with different concentrations of glutamate (0.1-1 mmol/L) increased lactate release from astrocytes, however the cell viability was not affected by the glutamate treatment. CONCLUSION: The current study provided direct evidence that exogenous glutamate treatment impaired the mitochondrial respiration capacity of astrocytes and enhanced aerobic glycolysis, which could be involved in glutamate injury or protection mechanisms in response to neurological disorders.


Subject(s)
Astrocytes/drug effects , Glutamic Acid/pharmacology , Glycolysis/drug effects , Mitochondria/drug effects , Animals , Astrocytes/metabolism , Cell Respiration/drug effects , Cells, Cultured , Lactic Acid/metabolism , Mitochondria/metabolism , Rats, Sprague-Dawley
9.
Zhongguo Zhong Yao Za Zhi ; 42(18): 3435-3442, 2017 Sep.
Article in Zh | MEDLINE | ID: mdl-29218925

ABSTRACT

In this paper,the potential climate factors affecting the Pairs polyphylla var. yunnanensis distribution in China at rational scales were selected from related literatures, using the sampling point geographic information from of P. polyphylla var. yunnanensis, combine the maximum entropy model (MaxEnt) with spatial analyst function of ArcGIS software, to study the climate suitability of P. polyphylla var. yunnanensis cultivating region in China and the leading climate factors. The results showed that, average rainfall in August, average rainfall in October, coefficient of variation of seasonal precipitation, the average temperature of the dry season, isothermal characteristic, average temperature in July were the leading climate factors affecting the potential distribution of P. polyphylla var. yunnanensis cultivating region in China, with their cumulative contribution rate reached 97.2% of all candidate climate factors. Existence probability of the region to be predicted of P. polyphylla var. yunnanensis through the constructed model, the climate unsuitable region, low, medium and high region of P. polyphylla var. yunnanensis in China were clarified and the threshold of climatic factors were gave and clarified the climate characteristics of the cultivating region in each climatic suitability division. The results of research can provide reference for production layout and introduction of P. polyphylla var. yunnanensis.


Subject(s)
Climate , Data Mining , Liliaceae/growth & development , China , Drugs, Chinese Herbal/analysis , Liliaceae/chemistry
10.
Eur J Immunol ; 45(1): 180-91, 2015 Jan.
Article in English | MEDLINE | ID: mdl-25329858

ABSTRACT

Forkhead box P3 (Foxp3)(+) regulatory T (Treg) cells maintain the immune tolerance and prevent inflammatory responses in the periphery. However, the presence of Treg cells in the CNS under steady state has not been studied. Here, for the first time, we show a substantial TCRαß (+) CD4(+) Foxp3(+) T-cell population (cerebral Treg cells) in the rat cerebrum, constituting more than 15% of the cerebral CD4(+) T-cell compartment. Cerebral Treg cells showed an activated/memory phenotype and expressed many Treg-cell signature genes at higher levels than peripheral Treg cells. Consistent with their activated/memory phenotype, cerebral Treg cells robustly restrained the LPS-induced inflammatory responses of brain microglia/macrophages, suggesting a role in maintaining the cerebral homeostasis by inhibiting the neuroinflammation. In addition, brain astrocytes were the helper cells that sustained Foxp3 expression in Treg cells through IL-2/STAT5 signaling, showing that the interaction between astrocytes and Treg cells contributes to the maintenance of Treg-cell identity in the brain. Taken together, our work represents the first study to characterize the phenotypic and functional features of Treg cells in the rat cerebrum. Our data have provided a novel insight for the contribution of Treg cells to the immunosurveillance and immunomodulation in the cerebrum under steady state.


Subject(s)
Astrocytes/immunology , Cerebrum/immunology , Encephalitis/immunology , Interleukin-10/immunology , Macrophages/immunology , T-Lymphocytes, Regulatory/immunology , Animals , Astrocytes/drug effects , Astrocytes/pathology , Cell Communication , Cerebrum/drug effects , Cerebrum/pathology , Encephalitis/pathology , Encephalitis/prevention & control , Gene Expression Regulation , Immunologic Memory , Immunologic Surveillance , Interleukin-10/genetics , Interleukin-2/genetics , Interleukin-2/immunology , Lipopolysaccharides/pharmacology , Macrophage Activation/drug effects , Macrophages/drug effects , Macrophages/pathology , Male , Primary Cell Culture , Rats , Rats, Sprague-Dawley , STAT5 Transcription Factor/genetics , STAT5 Transcription Factor/immunology , Signal Transduction , T-Lymphocytes, Regulatory/drug effects , T-Lymphocytes, Regulatory/pathology
11.
Arch Virol ; 161(11): 3081-93, 2016 Nov.
Article in English | MEDLINE | ID: mdl-27518404

ABSTRACT

The binding motif of BF2*15 major histocompatibility complex (MHC) class I was explored by analyzing the interaction between an infectious bronchitis virus octapeptide and BF2*15, and the cytotoxic T lymphocyte (CTL) epitope from the nucleoprotein (NP) of H5N1 virus was identified using experimental methods. Computational methods, including homology modeling, molecular dynamics simulation, and molecular docking analysis, were used. The recombinant plasmid pCAGGS-NP was constructed, and NP expression was confirmed by indirect immunofluorescence and Western blot in transfected 293T cells. Antibodies against NP in pCAGGS-NP-inoculated specific-pathogen-free chickens were detected by enzyme-linked immunosorbent assay (ELISA). Interferon γ (IFN-γ) mRNA was quantified, and IFN-γ production was evaluated using quantitative reverse transcription PCR and capture ELISA, respectively. CD8(+) T-lymphocyte proliferation was detected using flow cytometric analysis. The BF2*15 MHC class I binding motif "x-Arg/Lys-x-x-x-Arg/Lys" was explored. Quantification of chicken IFN-γ mRNA, evaluation of IFN-γ production, and measurement of CD8(+) T-lymphocyte proliferation confirmed that the peptide NP67-74 of H5N1 was the BF2*15 MHC-class-I-restricted CTL epitope.


Subject(s)
Epitopes, T-Lymphocyte/metabolism , HLA-B Antigens/metabolism , Influenza A Virus, H5N1 Subtype/immunology , RNA-Binding Proteins/immunology , T-Lymphocytes, Cytotoxic/immunology , Viral Core Proteins/immunology , Animals , Binding Sites , Cell Line , Chickens , Humans , Molecular Docking Simulation , Nucleocapsid Proteins , Protein Binding
12.
J Immunol ; 192(12): 6009-19, 2014 Jun 15.
Article in English | MEDLINE | ID: mdl-24829408

ABSTRACT

Signaling by the mammalian target of rapamycin (mTOR) plays an important role in the modulation of both innate and adaptive immune responses. However, the role and underlying mechanism of mTOR signaling in poststroke neuroinflammation are largely unexplored. In this study, we injected rapamycin, a mTOR inhibitor, by the intracerebroventricular route 6 h after focal ischemic stroke in rats. We found that rapamycin significantly reduced lesion volume and improved behavioral deficits. Notably, infiltration of γδ T cells and granulocytes, which are detrimental to the ischemic brain, was profoundly reduced after rapamycin treatment, as was the production of proinflammatory cytokines and chemokines by macrophages and microglia. Rapamycin treatment prevented brain macrophage polarization toward the M1 type. In addition, we also found that rapamycin significantly enhanced anti-inflammation activity of regulatory T cells (Tregs), which decreased production of proinflammatory cytokines and chemokines by macrophages and microglia. Depletion of Tregs partially elevated macrophage/microglia-induced neuroinflammation after stroke. Our data suggest that rapamycin can attenuate secondary injury and motor deficits after focal ischemia by enhancing the anti-inflammation activity of Tregs to restrain poststroke neuroinflammation.


Subject(s)
Brain Ischemia/immunology , Macrophages/immunology , Microglia/immunology , Signal Transduction/immunology , Stroke/immunology , T-Lymphocytes, Regulatory/immunology , TOR Serine-Threonine Kinases/immunology , Animals , Brain Ischemia/drug therapy , Brain Ischemia/pathology , Immunosuppressive Agents/pharmacology , Inflammation/drug therapy , Inflammation/immunology , Inflammation/pathology , Macrophages/pathology , Male , Microglia/pathology , Rats , Rats, Sprague-Dawley , Receptors, Antigen, T-Cell, gamma-delta/immunology , Signal Transduction/drug effects , Sirolimus/pharmacology , Stroke/pathology , T-Lymphocytes, Regulatory/pathology , TOR Serine-Threonine Kinases/antagonists & inhibitors
13.
Acta Neurochir Suppl ; 121: 227-36, 2016.
Article in English | MEDLINE | ID: mdl-26463954

ABSTRACT

The neuroprotective effect of methylene blue (MB) has been identified against various brain disorders, including ischemic stroke. In the present study, we evaluated the effects of MB on postischemic brain edema using magnetic resonance imaging (MRI) and transmission electron microscopy (TEM). Adult male rats were subjected to transient focal cerebral ischemia induced by 1 h middle cerebral artery occlusion (MCAO), followed by reperfusion. MB was infused intravenously immediately after reperfusion (3 mg/kg) and again at 3 h post-occlusion (1.5 mg/kg). Normal saline was administered as vehicle control. Sequential MRIs, including apparent diffusion coefficient (ADC) and T2-weighted imaging (T2WI), were obtained at 0.5, 2.5, and 48 h after the onset of stroke. Separated groups of animals were sacrificed at 2.5 and 48 h after stroke for ultrastructural analysis by TEM. In addition, final lesion volumes were analyzed by triphenyltetrazolium chloride (TTC) staining at 48 h after stroke. Ischemic stroke induced ADC lesion volume at 0.5 h during MCAOs that were temporally recovered at 1.5 h after reperfusion. No significant difference in ADC-defined lesion was observed between vehicle and MB treatment groups. At 48 h after stroke, MB significantly reduced ADC lesion and T2WI lesion volume and attenuated cerebral swelling. Consistently, MB treatment significantly decreased TTC-defined lesion volume at 48 h after stroke. TEM revealed remarkable swollen astrocytes, astrocytic perivascular end-feet, and concurrent shrunken neurons in the penumbra at 2.5 and 48 h after MCAO. MB treatment attenuated astrocyte swelling, the perivascular astrocytic foot process, and endothelium and also alleviated neuron degeneration. This study demonstrated that MB could decrease postischemic brain edema and provided additional evidence that future clinical investigation of MB for the treatment of ischemic stroke is warrented.


Subject(s)
Brain Edema/diagnostic imaging , Brain/drug effects , Enzyme Inhibitors/pharmacology , Infarction, Middle Cerebral Artery/diagnostic imaging , Ischemic Attack, Transient/diagnostic imaging , Methylene Blue/pharmacology , Reperfusion Injury/diagnostic imaging , Animals , Brain/diagnostic imaging , Brain/ultrastructure , Brain Edema/etiology , Infarction, Middle Cerebral Artery/complications , Magnetic Resonance Imaging , Male , Microscopy, Electron, Transmission , Neuroprotective Agents/pharmacology , Rats , Rats, Sprague-Dawley , Reperfusion Injury/complications
14.
J Biol Chem ; 289(34): 23318-28, 2014 Aug 22.
Article in English | MEDLINE | ID: mdl-24986863

ABSTRACT

Mutations in the cytosolic NADP(+)-dependent isocitrate dehydrogenase (IDH1) occur in several types of cancer, and altered cellular metabolism associated with IDH1 mutations presents unique therapeutic opportunities. By altering IDH1, these mutations target a critical step in reductive glutamine metabolism, the metabolic pathway that converts glutamine ultimately to acetyl-CoA for biosynthetic processes. While IDH1-mutated cells are sensitive to therapies that target glutamine metabolism, the effect of IDH1 mutations on reductive glutamine metabolism remains poorly understood. To explore this issue, we investigated the effect of a knock-in, single-codon IDH1-R132H mutation on the metabolism of the HCT116 colorectal adenocarcinoma cell line. Here we report the R132H-isobolome by using targeted (13)C isotopomer tracer fate analysis to trace the metabolic fate of glucose and glutamine in this system. We show that introduction of the R132H mutation into IDH1 up-regulates the contribution of glutamine to lipogenesis in hypoxia, but not in normoxia. Treatment of cells with a d-2-hydroxyglutarate (d-2HG) ester recapitulated these changes, indicating that the alterations observed in the knocked-in cells were mediated by d-2HG produced by the IDH1 mutant. These studies provide a dynamic mechanistic basis for metabolic alterations observed in IDH1-mutated tumors and uncover potential therapeutic targets in IDH1-mutated cancers.


Subject(s)
Cell Hypoxia , Glutarates/metabolism , Isocitrate Dehydrogenase/genetics , Neoplasms/enzymology , Cell Line, Tumor , Glycolysis , HCT116 Cells , Humans , Isocitrate Dehydrogenase/metabolism , Mitochondria/physiology , Neoplasms/pathology
15.
Anticancer Drugs ; 26(3): 293-300, 2015 Mar.
Article in English | MEDLINE | ID: mdl-25535979

ABSTRACT

Tamoxifen, a selective estrogen receptor modulator, is widely used in the chemotherapy of estrogen receptor-positive breast cancer. Recent studies have indicated that tamoxifen might have a potential chemotherapeutic effect on glioma. In the present study, we determined the chemotherapeutic action of tamoxifen on human glioma cell lines. Methylation of 06-methylguanine-DNA methyltransferase was identified in A172, U251, and BT325 glioma cell lines, but not in the U87 cell line. Consistently, A172, U251, and BT325 cell lines are resistant to temozolomide. Tamoxifen induced significant cytotoxic action in A172, U251, BT325, and U87 cell lines. Further, Hoechst 33342 staining and apoptosis flow cytometric analysis demonstrated that tamoxifen induced apoptosis in the BT325 cell line. Mitochondrial complex analysis indicated that tamoxifen, but not other estrogen receptor modulators, dose-dependently inhibits complex I activity. In summary, our study suggests that tamoxifen might have a chemotherapeutic effect on temozolomide-resistant glioma through its direct action on mitochondrial complex I inhibition and could provide further evidence to support future clinical trials of tamoxifen for the treatment of glioblastoma.


Subject(s)
Brain Neoplasms/drug therapy , Dacarbazine/analogs & derivatives , Drug Resistance, Neoplasm/drug effects , Glioma/drug therapy , Tamoxifen/pharmacology , Animals , Antineoplastic Agents, Hormonal/pharmacology , Apoptosis/drug effects , Brain Neoplasms/metabolism , Cell Line, Tumor/drug effects , DNA Modification Methylases/genetics , DNA Modification Methylases/metabolism , DNA Repair Enzymes/genetics , DNA Repair Enzymes/metabolism , Dacarbazine/pharmacology , Dose-Response Relationship, Drug , Electron Transport Complex I/antagonists & inhibitors , Glioma/metabolism , Humans , Male , Methylation , Mitochondria/metabolism , Promoter Regions, Genetic , Rats, Sprague-Dawley , Temozolomide , Tumor Suppressor Proteins/genetics , Tumor Suppressor Proteins/metabolism
16.
Biomed Environ Sci ; 28(3): 199-205, 2015 Mar.
Article in English | MEDLINE | ID: mdl-25800444

ABSTRACT

OBJECTIVE: To investigate the role of extracellular signal-regulated kinase1/2 (ERK1/2) pathway in the regulation of aquaporin 4 (AQP4) expression in cultured astrocytes after scratch-injury. METHODS: The scratch-injury model was produced in cultured astrocytes of rat by a 10-µL plastic pipette tip. The morphological changes of astrocytes and lactate dehydrogenase (LDH) leakages were observed to assess the degree of scratch-injury. AQP4 expression was detected by immunofluorescence staining and Western blot, and phosphorylated-ERK1/2 (p-ERK1/2) expression was determined by Western blot. To explore the effect of ERK1/2 pathway on AQP4 expression in scratch-injured astrocytes, 10 µmol/L U0126 (ERK1/2 inhibitor) was incubated in the medium at 30 min before the scratch-injury in some groups. RESULTS: Increases in LDH leakage were observed at 1, 12, and 24 h after scratch-injury, and AQP4 expression was reduced simultaneously. Decrease in AQP4 expression was associated with a significant increase in ERK1/2 activation. Furthermore, pretreatment with U0126 blocked both ERK1/2 activation and decrease in AQP4 expression induced by scratch-injury. CONCLUSION: These results indicate that ERK1/2 pathway down-regulates AQP4 expression in scratch-injured astrocytes, and ERK1/2 pathway might be a novel therapeutic target in reversing the effects of astrocytes that contribute to traumatic brain edema.


Subject(s)
Aquaporin 4/metabolism , Astrocytes/metabolism , Down-Regulation , Extracellular Signal-Regulated MAP Kinases/metabolism , MAP Kinase Signaling System , Skin/injuries , Animals , Astrocytes/enzymology , Butadienes/administration & dosage , Cells, Cultured , Enzyme Activation , Nitriles/administration & dosage , Rats , Rats, Wistar
17.
Int J Mol Sci ; 16(11): 26530-42, 2015 Nov 05.
Article in English | MEDLINE | ID: mdl-26556348

ABSTRACT

Phosphodiesterase9A (PDE9A) is a cyclic guanosine monophosphate (cGMP)-specific enzyme widely expressed among the tissues, which is important in activating cGMP-dependent signaling pathways. In our previous genome-wide association study, a single nucleotide polymorphism (SNP) (BTA-55340-no-rs(b)) located in the intron 14 of PDE9A, was found to be significantly associated with protein yield. In addition, we found that PDE9A was highly expressed in mammary gland by analyzing its mRNA expression in different tissues. The objectives of this study were to identify genetic polymorphisms of PDE9A and to determine the effects of these variants on milk production traits in dairy cattle. DNA sequencing identified 11 single nucleotide polymorphisms (SNPs) and six SNPs in 5' regulatory region were genotyped to test for the subsequent association analyses. After Bonferroni correction for multiple testing, all these identified SNPs were statistically significant for one or more milk production traits (p < 0.0001~0.0077). Interestingly, haplotype-based association analysis revealed similar effects on milk production traits (p < 0.01). In follow-up RNA expression analyses, two SNPs (c.-1376 G>A, c.-724 A>G) were involved in the regulation of gene expression. Consequently, our findings provide confirmatory evidences for associations of PDE9A variants with milk production traits and these identified SNPs may serve as genetic markers to accelerate Chinese Holstein breeding program.


Subject(s)
3',5'-Cyclic-AMP Phosphodiesterases/genetics , Genome-Wide Association Study , Milk , Quantitative Trait, Heritable , Alleles , Animals , Binding Sites , Cattle , Evolution, Molecular , Gene Expression , Haplotypes , Linkage Disequilibrium , Mutation , Phylogeny , Polymorphism, Single Nucleotide , Protein Binding , Selection, Genetic , Transcription Factors/metabolism
19.
J Biol Chem ; 288(13): 9153-64, 2013 Mar 29.
Article in English | MEDLINE | ID: mdl-23408428

ABSTRACT

Glioblastoma multiforme (GBM), like most cancers, possesses a unique bioenergetic state of aerobic glycolysis known as the Warburg effect. Here, we documented that methylene blue (MB) reverses the Warburg effect evidenced by the increasing of oxygen consumption and reduction of lactate production in GBM cell lines. MB decreases GBM cell proliferation and halts the cell cycle in S phase. Through activation of AMP-activated protein kinase, MB inactivates downstream acetyl-CoA carboxylase and decreases cyclin expression. Structure-activity relationship analysis demonstrated that toluidine blue O, an MB derivative with similar bioenergetic actions, exerts similar action in GBM cell proliferation. In contrast, two other MB derivatives, 2-chlorophenothiazine and promethazine, exert no effect on cellular bioenergetics and do not inhibit GBM cell proliferation. MB inhibits cell proliferation in both temozolomide-sensitive and -insensitive GBM cell lines. In a human GBM xenograft model, a single daily dosage of MB does not activate AMP-activated protein kinase signaling, and no tumor regression was observed. In summary, the current study provides the first in vitro proof of concept that reversal of Warburg effect might be a novel therapy for GBM.


Subject(s)
Brain Neoplasms/therapy , Glioblastoma/therapy , Adenosine Triphosphate/metabolism , Animals , Annexin A5/pharmacology , Antineoplastic Agents/pharmacology , Antineoplastic Agents, Alkylating/pharmacology , Cell Cycle , Cell Line, Tumor , Cell Proliferation , Dacarbazine/analogs & derivatives , Dacarbazine/pharmacology , Energy Metabolism , Female , Humans , Lactates/metabolism , Methylene Blue/pharmacology , Mice , Mice, Inbred BALB C , Mice, Nude , Neoplasm Transplantation , Oxygen Consumption , Structure-Activity Relationship , Temozolomide , Tolonium Chloride/pharmacology
20.
Neuroimage ; 85 Pt 1: 566-82, 2014 Jan 15.
Article in English | MEDLINE | ID: mdl-23872158

ABSTRACT

Diffuse optical tomography (DOT) has been used by several groups to assess cerebral hemodynamics of cerebral ischemia in humans and animals. In this study, we combined DOT with an indocyanine green (ICG)-tracking method to achieve interleaved images of cerebral hemodynamics and blood flow index (BFI) using two middle cerebral artery occlusion (MCAO) rat models. To achieve volumetric images with high-spatial resolution, we first integrated a depth compensation algorithm (DCA) with a volumetric mesh-based rat head model to generate three-dimensional (3D) DOT on a rat brain atlas. Then, the experimental DOT data from two rat models were collected using interleaved strategy for cerebral hemodynamics and BFI during and after ischemic stroke, with and without a thrombolytic therapy for the embolic MCAO model. The acquired animal data were further analyzed using the integrated rat-atlas-guided DOT method to form time-evolving 3D images of both cerebral hemodynamics and BFI. In particular, we were able to show and identify therapeutic outcomes of a thrombolytic treatment applied to the embolism-induced ischemic model. This paper demonstrates that volumetric DOT is capable of providing high-quality, interleaved images of cerebral hemodynamics and blood perfusion in small animals during and after ischemic stroke, with excellent 3D visualization and quantifications.


Subject(s)
Brain Ischemia/pathology , Brain Ischemia/therapy , Brain/pathology , Cerebrovascular Circulation/physiology , Functional Neuroimaging/methods , Spectroscopy, Near-Infrared/methods , Stroke/pathology , Stroke/therapy , Tomography, Optical/methods , Algorithms , Animals , Atlases as Topic , Coloring Agents , Data Interpretation, Statistical , Disease Models, Animal , Image Processing, Computer-Assisted , Indocyanine Green , Intracranial Embolism/complications , Male , Rats , Rats, Sprague-Dawley
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