ABSTRACT
OBJECTIVE: To investigate the mitochondrial translocation of hypoxia inducible factor-3α (HIF-3α) under normoxia and hypoxia and its physiological and pathological meanings. METHODS: â After hypoxic (1%O2) or DMOG, CoCl2 treatments mimicking the hypoxic treatment, Western blot and immunofluorescence were used to examine the HIF-3α expression in mitochondria of HeLa and ACHN cells, respectively. â¡The protease sensitivity experiment was used to explore the sub-organelle localization of HIF-3α in mitochondria. â¢Western blot was used to examine mitochondrial HIF-3α in the normal mouse tissues and human liver carcinoma tissues. RESULTS: â In HeLa and ACHN cells, HIF-3α translocated to mitochondria under normoxia and hypoxia, and its mitochondrial expression was higher under hypoxia; â¡The protease sensitivity of HIF-3α was similar to proteins locating in the mitochondrial outer membrane; â¢Mitochondrial HIF-3α expressed in multiple normal mouse tissues; The expression of mitochondrial HIF-3α was higher in human liver carcinoma tissues than the normal and adjacent tissues. CONCLUSIONS: HIF-3α translocated to mitochondrial outer membrane under both normoxia and hypoxia, and hypoxia could up-regulated HIF-3α mitochondrial translocation. Meanwhile, the phenomenon may be involved in the process of liver carcinoma.
Subject(s)
Basic Helix-Loop-Helix Transcription Factors/metabolism , Liver Neoplasms/metabolism , Mitochondrial Membranes/metabolism , Animals , Apoptosis Regulatory Proteins , Cell Hypoxia , HeLa Cells , Humans , Mice , Repressor Proteins , Transcription FactorsABSTRACT
Deficiency of primary cilia formation by knockout kinesin family member 3A (Kif3a) in mature osteoblasts led to osteopenia and enhanced adipogenesis. Adipogenesis plays an important role in adipose tissue expansion by High-fat-diet (HFD) induced obesity. Whether primary cilia participate in high-fat-diet induced adiposity remains unclear. In this study, we found that the number and length of primary cilia and expression levels of KIF3A and intraflagellar transport 88 homolog (IFT88) mRNA and proteins reached peak on the day 3 of adipogenesis, followed by a decrease to reach low basal expression levels at day 9 when differentiated to lipid accumulating adipocytes in VAT-SVFs derived from lean mice. The number of primary cilia was reduced by shRNA and chemical methods, leading to elevated transcripts of Pparγ, Cebp-α, Srebp-1, and Fasn and protein levels of PPARγ and FASN. Similar to the proadipogenic effect by the inhibition of primary cilia formation in control VAT-SVFs, HFD caused severe reduction of primary cilia formation and enhancement of adipogenesis in VAT-SVFs cultures. Flow cytometry analysis revealed percentage of G2/M phase cells and the protein expression of Cyclin A2 and CDK2 increased in control VAT-SVFs by knockdown of primary cilia with shRNA or chemical methods and HFD induced obese VAT-SVFs. In conclusion, the expression of primary cilia was in reverse correlation with adipogenic differentiation. HFD caused severe defects of primary cilia in VAT-SVFs, leading to adipose tissue expansion by enhancement of adipogenesis through promoting cell cycle re-entry at the early stage of adipogenesis.
Subject(s)
Cilia/drug effects , Diet, High-Fat/adverse effects , Obesity, Abdominal/chemically induced , 3T3-L1 Cells , Adipocytes/cytology , Adipocytes/drug effects , Adipocytes/metabolism , Adipogenesis , Animals , Body Weight/drug effects , Cell Cycle/drug effects , Cell Differentiation , Cilia/metabolism , Kinesins/genetics , Kinesins/metabolism , Male , Mice , Obesity, Abdominal/genetics , Obesity, Abdominal/metabolism , Signal Transduction/drug effects , Tumor Suppressor Proteins/genetics , Tumor Suppressor Proteins/metabolismABSTRACT
The glypican-3 (GPC3) receptor is overexpressed in hepatocellular carcinoma (HCC) and is a potential diagnostic and therapeutic target. GPC3-targeted molecular imaging will be helpful to differentiate diagnosis and guide therapy. In the present study, we will develop a novel PET probe for imaging the expression of GPC-3. L5 (sequence: RLNVGGTYFLTTRQ), a GPC3 targeting peptide, was labeled with 5-carboxyfluorescein (FAM) and 18F-fluoride. Cell binding tests were performed to identify the binding specificity of FAM-L5 and 18F radiolabeled peptide. MicroPET/CT imaging was used to determine the potential of a novel PET tracer for visualizing HCC tumors with a high expression of GPC3. In vitro binding tests showed that the uptake of FAM-L5 in HepG2 cells (high expression of GPC3) was significantly higher than that of HL-7702 cells (negative expression of GPC3) (mean fluorescent intensity: 14,094 ± 797 vs. 2765 ± 314 events, t = 32.363, P = 0.000). Confocal fluorescent imaging identified that FAM-L5 accumulated where the GPC3 receptor was located. A novel PET tracer (18F-AlF-NODA-MP-6-Aoc-L5) was successfully labeled by chelation chemistry. In vitro cell uptake studies showed that 18F-AlF-NODA-MP-6-Aoc-L5 can bind to HepG2 tumor cells and was stable in PBS and mouse serum stability tests. MicroPET/CT showed that HepG2 tumors could be clearly visualized with a tumor/muscle ratio of 2.46 ± 0.53. However, the tumor/liver ratio was low (0.93 ± 0.16) due to the high physiological uptake in the liver. This study demonstrates that FAM and the 18F-labeled L5 peptide can selectively target HCC with a high expression of GPC3 in vitro and in vivo. 18F-AlF-NODA-MP-C6-L5 has the potential to be a GPC3 target tracer but requires some chemical modifications to achieve a high enough tumor/liver ratio for detection of the tumor in the liver.
Subject(s)
Carcinoma, Hepatocellular/diagnostic imaging , Glypicans/metabolism , Liver Neoplasms/diagnostic imaging , Oligopeptides/metabolism , Positron-Emission Tomography , Animals , Biomarkers, Tumor , Carcinoma, Hepatocellular/metabolism , Carcinoma, Hepatocellular/pathology , Cell Line , Disease Models, Animal , Female , Fluoresceins/chemistry , Fluorine Radioisotopes/chemistry , Hep G2 Cells , Humans , Liver/cytology , Liver/metabolism , Liver/pathology , Liver Neoplasms/metabolism , Liver Neoplasms/pathology , Male , Mice , Muscles/metabolism , Oligopeptides/chemical synthesis , Oligopeptides/chemistry , Oligopeptides/pharmacokinetics , Organ Specificity , Protein Stability , Tissue DistributionABSTRACT
Neurons rely on glia to recycle neurotransmitters such as glutamate and histamine for sustained signaling. Both mammalian and insect glia form intercellular gap-junction networks, but their functional significance underlying neurotransmitter recycling is unknown. Using the Drosophila visual system as a genetic model, here we show that a multicellular glial network transports neurotransmitter metabolites between perisynaptic glia and neuronal cell bodies to mediate long-distance recycling of neurotransmitter. In the first visual neuropil (lamina), which contains a multilayer glial network, photoreceptor axons release histamine to hyperpolarize secondary sensory neurons. Subsequently, the released histamine is taken up by perisynaptic epithelial glia and converted into inactive carcinine through conjugation with ß-alanine for transport. In contrast to a previous assumption that epithelial glia deliver carcinine directly back to photoreceptor axons for histamine regeneration within the lamina, we detected both carcinine and ß-alanine in the fly retina, where they are found in photoreceptor cell bodies and surrounding pigment glial cells. Downregulating Inx2 gap junctions within the laminar glial network causes ß-alanine accumulation in retinal pigment cells and impairs carcinine synthesis, leading to reduced histamine levels and photoreceptor synaptic vesicles. Consequently, visual transmission is impaired and the fly is less responsive in a visual alert analysis compared with wild type. Our results suggest that a gap junction-dependent laminar and retinal glial network transports histamine metabolites between perisynaptic glia and photoreceptor cell bodies to mediate a novel, long-distance mechanism of neurotransmitter recycling, highlighting the importance of glial networks in the regulation of neuronal functions.
Subject(s)
Drosophila melanogaster/physiology , Neuroglia/physiology , Neurotransmitter Agents/metabolism , Photoreceptor Cells, Invertebrate/physiology , Synaptic Transmission/physiology , Vision, Ocular/physiology , Animals , Biological Transport/physiology , Carnosine/analogs & derivatives , Carnosine/metabolism , Connexins/genetics , Drosophila Proteins/genetics , Electroretinography , Fluoroimmunoassay , Gene Knockdown Techniques , Histamine/metabolism , Microscopy, Confocal , Microscopy, Electron, Transmission , RNA Interference , Retina/metabolism , beta-Alanine/metabolismABSTRACT
Oligosaccharide chains of newly synthesized membrane receptors are trimmed and modified to optimize their trafficking and/or signalling before delivery to the cell surface. For most membrane receptors, the functional significance of oligosaccharide chain modification is unknown. During the maturation of Rh1 rhodopsin, a Drosophila light receptor, the oligosaccharide chain is trimmed extensively. Neither the functional significance of this modification nor the enzymes mediating this process are known. Here, we identify a dmppe (Drosophila metallophosphoesterase) mutant with incomplete deglycosylation of Rh1, and show that the retained oligosaccharide chain does not affect Rh1 localization or signalling. The incomplete deglycosylation, however, renders Rh1 more sensitive to endocytic degradation, and causes morphological and functional defects in photoreceptors of aged dmppe flies. We further demonstrate that the dMPPE protein functions as an Mn(2+)/Zn(2+)-dependent phosphoesterase and mediates in vivo dephosphorylation of α-Man-II. Most importantly, the dephosphorylated α-Man-II is required for the removal of the Rh1 oligosaccharide chain. These observations suggest that the glycosylation status of membrane proteins is controlled through phosphorylation/dephosphorylation, and that MPPE acts as the phosphoesterase in this regulation.
Subject(s)
Drosophila Proteins/metabolism , Drosophila/enzymology , Phosphoprotein Phosphatases/metabolism , Rhodopsin/metabolism , alpha-Mannosidase/metabolism , Animals , Cations, Divalent/metabolism , Coenzymes/metabolism , Drosophila/genetics , Glycosylation , Manganese/metabolism , Phosphoprotein Phosphatases/deficiency , Zinc/metabolismABSTRACT
Neurons express various combinations of neurotransmitter receptor (NR) subunits and receive inputs from multiple neuron types expressing different neurotransmitters. Localizing NR subunits to specific synaptic inputs has been challenging. Here, we use epitope-tagged endogenous NR subunits, expansion light-sheet microscopy, and electron microscopy (EM) connectomics to molecularly characterize synapses in Drosophila. We show that in directionally selective motion-sensitive neurons, different multiple NRs elaborated a highly stereotyped molecular topography with NR localized to specific domains receiving cell-type-specific inputs. Developmental studies suggested that NRs or complexes of them with other membrane proteins determine patterns of synaptic inputs. In support of this model, we identify a transmembrane protein selectively associated with a subset of spatially restricted synapses and demonstrate its requirement for synapse formation through genetic analysis. We propose that mechanisms that regulate the precise spatial distribution of NRs provide a molecular cartography specifying the patterns of synaptic connections onto dendrites.
Subject(s)
Connectome , Synapses/physiology , Motor Neurons/metabolism , Microscopy, Electron , Receptors, GABA-A/metabolismABSTRACT
Reversed-phase liquid chromatography (RPLC) represents an effective separation method, and is widely employed as the second dimension in most 2D-LC systems. Nevertheless, the solvent effect of the eluent from the first dimension on RPLC presents a challenge to the online coupling of RPLC with other separation modes, particularly normal phase liquid chromatography (NPLC). To address this issue, a comprehensive understanding of the solvent effect is essential. Following a comprehensive investigation into the influence of diverse solvents on RPLC separations, it was observed that alkane solvents, such as n-hexane, exhibited a pronounced tendency to be retained during RPLC separations. Such solvents do not affect the analysis of samples with weaker retention abilities than themselves, even when a large injection volume is used. The solvent effect was thus reduced by employing n-hexane-based solvent dilution. Leveraging the markedly enhanced solvent tolerance and extensive injection volume in RPLC, a versatile integration of the NPLC and RPLC was devised, necessitating merely a purge pump and a 10 port 2 position valve in conjunction with two sample loops. The novel 2D-LC system was then deployed for the analysis of propolis, a naturally occurring complex sample, and demonstrated remarkable separation efficiency.
ABSTRACT
Appropriate termination of the phototransduction cascade is critical for photoreceptors to achieve high temporal resolution and to prevent excessive Ca(2+)-induced cell toxicity. Using a genetic screen to identify defective photoresponse mutants in Drosophila, we isolated and identified a novel Gα(q) mutant allele, which has defects in both activation and deactivation. We revealed that G(q) modulates the termination of the light response and that metarhodopsin/G(q) interaction affects subsequent arrestin-rhodopsin (Arr2-Rh1) binding, which mediates the deactivation of metarhodopsin. We further showed that the Gα(q) mutant undergoes light-dependent retinal degeneration, which is due to the slow accumulation of stable Arr2-Rh1 complexes. Our study revealed the roles of G(q) in mediating photoresponse termination and in preventing retinal degeneration. This pathway may represent a general rapid feedback regulation of G protein-coupled receptor signaling.
Subject(s)
GTP-Binding Protein alpha Subunits, Gq-G11/metabolism , Retinal Degeneration/metabolism , Retinal Degeneration/prevention & control , Alleles , Animals , Animals, Genetically Modified , Arrestins/chemistry , Drosophila Proteins/chemistry , Drosophila melanogaster/genetics , Electrophysiology , Light , Light Signal Transduction , Models, Genetic , Mutation , Photoreceptor Cells, Invertebrate/metabolism , Receptors, G-Protein-Coupled/chemistry , Rhodopsin/chemistry , Rhodopsin/metabolismABSTRACT
ABSTRACT: System paclitaxel-based chemotherapy is the first-line treatment regimen of defense against breast cancer, but inherent or acquired chemotherapy resistance remains a major obstacle in breast cancer therapy. Elucidating the molecular mechanism of chemoresistance is essential to improve the outcome of patients with breast cancer. Here, we demonstrate that intraflagellar transport 20 (IFT20) is positively associated with shorter relapse-free survival in patients with system paclitaxel-based chemotherapy. High-expressed IFT20 in breast cancer cells increases resistance to cell death upon paclitaxel treatment; in contrast, IFT20 knockdown enhances apoptosis in breast cancer cells in response to paclitaxel. Mechanistically, IFT20 triggers ß-arrestin-1 to bind with apoptosis signal-regulating kinase 1 (ASK1) and promotes the ubiquitination of ASK1 degradation, leading to attenuating ASK1 signaling and its downstream JNK cascades, which helps cells to escape from cell death during paclitaxel treatment. Our results reveal that IFT20 drives paclitaxel resistance through modulating ASK1 signaling and identifies IFT20 as a potential molecular biomarker for predicting the response to paclitaxel therapeutic in breast cancer. IMPLICATIONS: IFT20 drives paclitaxel resistance through modulating ASK1 signaling and IFT20 may act as a potential molecular biomarker for predicting the response to paclitaxel therapeutic in breast cancer.
Subject(s)
Breast Neoplasms , Paclitaxel , Humans , Female , Paclitaxel/pharmacology , Paclitaxel/therapeutic use , Breast Neoplasms/drug therapy , Breast Neoplasms/genetics , Breast Neoplasms/metabolism , beta-Arrestin 1/genetics , beta-Arrestin 1/metabolism , beta-Arrestin 1/therapeutic use , MAP Kinase Kinase Kinase 5/genetics , MAP Kinase Kinase Kinase 5/metabolism , MAP Kinase Kinase Kinase 5/therapeutic use , Cell Line, Tumor , Neoplasm Recurrence, Local/drug therapy , Apoptosis , Drug Resistance, Neoplasm , Carrier ProteinsABSTRACT
Neurons express different combinations of neurotransmitter receptor (NR) subunits and receive inputs from multiple neuron types expressing different neurotransmitters. Localizing NR subunits to specific synaptic inputs has been challenging. Here we use epitope tagged endogenous NR subunits, expansion light-sheet microscopy, and EM connectomics to molecularly characterize synapses in Drosophila. We show that in directionally selective motion sensitive neurons, different multiple NRs elaborated a highly stereotyped molecular topography with NR localized to specific domains receiving cell-type specific inputs. Developmental studies suggested that NRs or complexes of them with other membrane proteins determines patterns of synaptic inputs. In support of this model, we identify a transmembrane protein associated selectively with a subset of spatially restricted synapses and demonstrate through genetic analysis its requirement for synapse formation. We propose that mechanisms which regulate the precise spatial distribution of NRs provide a molecular cartography specifying the patterns of synaptic connections onto dendrites.
ABSTRACT
BACKGROUND: In 2003, Plasmodium vivax malaria has re-emerged in central eastern China including Yongcheng prefecture, Henan Province, where no case has been reported for eleven years. Our goals were to detect the space-time distribution pattern of malaria and to determine significant environmental variables contributing to malaria incidence in Yongcheng from 2006 to 2010, thus providing scientific basis for further optimizing current malaria surveillance and control programs. METHODS: This study examined the spatial and temporal heterogeneities in the risk of malaria and the influencing factors on malaria incidence using geographical information system (GIS) and time series analysis. Univariate analysis was conducted to estimate the crude correlations between malaria incidence and environmental variables, such as mosquito abundance and climatic factors. Multivariate analysis was implemented to construct predictive models to explore the principal environmental determinants on malaria epidemic using a Generalized Estimating Equation (GEE) approach. RESULTS: Annual malaria incidence at town-level decreased from the north to south, and monthly incidence at prefecture-level demonstrated a strong seasonal pattern with a peak from July to November. Yearly malaria incidence had a visual spatial association with yearly average temperature. Moreover, the best-fit temporal model (model 2) (QIC = 16.934, P<0.001, R2 = 0.818) indicated that significant factors contributing to malaria incidence were maximum temperature at one month lag, average humidity at one month lag, and malaria incidence of the previous month. CONCLUSIONS: Findings supported the effects of environment factors on malaria incidence and indicated that malaria control targets should vary with intensity of malaria incidence, with more public resource allocated to control the source of infections instead of large scale An. sinensis control when malaria incidence was at a low level, which would benefit for optimizing the malaria surveillance project in China and some other countries with unstable or low malaria transmission.
Subject(s)
Malaria, Vivax/epidemiology , Animals , Anopheles/parasitology , China/epidemiology , Environment , Geographic Information Systems , Humans , Incidence , Malaria, Vivax/etiology , Plasmodium vivax , Spatio-Temporal Analysis , WeatherABSTRACT
Inwardly rectifying potassium channels (Kir) are a special subset of potassium selective ion channels which pass potassium more easily into rather than out of the cell. These channels mediate a variety of cellular functions, including control of membrane resting potential, maintenance of potassium homeostasis and regulation of cellular metabolism. Given the existence of fifteen Kir genes in mammals, current genetic studies using mutant animals that lack a single channel may have missed many important physiological functions of these channels due to gene redundancy. This issue can be circumvented by using a simple model organism like Drosophila, whose genome encodes only 3 Kir proteins. The sophisticated genetic approaches of Drosophila may also provide powerful tools to identify additional regulation mechanisms of Kir channels. Here we provide an overview of the progress made in elucidating the function of Drosophila Kir channels. The knowledge of Drosophila Kir channels may lead us to uncover novel functions and regulation mechanisms of human Kir channels and help on pathological studies of related diseases.
Subject(s)
Drosophila/physiology , Potassium Channels, Inwardly Rectifying/physiology , Animals , Membrane Potentials , Potassium/physiologyABSTRACT
Normal termination of signaling is essential to reset signaling cascades, especially those such as phototransduction that are turned on and off with great rapidity. Genetic approaches in Drosophila led to the identification of several proteins required for termination, including protein kinase C (PKC), NINAC (neither inactivation nor afterpotential C) p174, which consists of fused protein kinase and myosin domains, and a PDZ (postsynaptic density-95/Discs Large/zona occludens-1) scaffold protein, INAD (inactivation no afterpotential D). Here, we describe a mutation affecting a poorly characterized but evolutionarily conserved protein, Retinophilin (Retin), which is expressed primarily in the phototransducing compartment of photoreceptor cells, the rhabdomeres. Retin and NINAC formed a complex and were mutually dependent on each other for expression. Loss of retin resulted in an age-dependent impairment in termination of phototransduction. Mutations that affect termination of the photoresponse typically lead to a reduction in levels of the major rhodopsin (Rh1) to attenuate signaling. Consistent with the slower termination in retin(1), the mutant photoreceptor cells exhibited increased endocytosis of Rh1 and a decline in Rh1 protein. The slower termination in retin(1) was a consequence of a cascade of defects, which began with the reduction in NINAC p174 levels. The diminished p174 concentration caused a decrease in INAD. Because PKC requires interaction with INAD for protein stability, this leads to reduction in PKC levels. The decline in PKC was age dependent and paralleled the onset of the termination phenotype in retin(1) mutant flies. We conclude that the slower termination of the photoresponse in retin(1) resulted from a requirement for the Retin/NINAC complex for stability of INAD and PKC.
Subject(s)
Drosophila Proteins/physiology , Eye Proteins/physiology , Light Signal Transduction/physiology , Myosin Heavy Chains/physiology , Myosins/physiology , Protein Kinase C/physiology , Animals , Animals, Genetically Modified , Drosophila , Drosophila Proteins/biosynthesis , Drosophila Proteins/chemistry , Drosophila Proteins/metabolism , Enzyme Stability/physiology , Eye Proteins/biosynthesis , Eye Proteins/chemistry , Eye Proteins/metabolism , Myosin Heavy Chains/chemistry , Myosins/chemistry , Photic Stimulation/methods , Protein Kinase C/chemistryABSTRACT
Rapid deactivation of the Drosophila light receptor rhodopsin, through a visual arrestin Arr2 and a pathway that involves a transcription factor dCAMTA, is required for timely termination of light responses in the photoreceptor neuron. Here we report that this process is also critical for maintenance of the photoreceptor sensitivity. In both dCAMTA- and arr2-mutant flies, the endocytosis of the major rhodopsin Rh1 was dramatically increased, which was mediated by a G(q) protein that signals downstream of rhodopsin in the visual transduction pathway. Consequently, the Rh1 level was downregulated and the photoreceptor became less sensitive to light. Remarkably, the G(q)-stimulated Rh1 endocytosis does not require phospholipase C, a known effector of G(q), but depends on a tetraspanin protein. Our work has identified an arrestin-independent endocytic pathway of G protein-coupled receptor in the fly. This pathway may also function in mammals and mediate an early feedback regulation of receptor signaling.
Subject(s)
Drosophila Proteins/metabolism , Drosophila melanogaster , Endocytosis/physiology , GTP-Binding Protein alpha Subunits, Gq-G11/metabolism , Rhodopsin/metabolism , Second Messenger Systems/physiology , Animals , Animals, Genetically Modified , Arrestins/genetics , Arrestins/metabolism , Drosophila Proteins/genetics , Drosophila melanogaster/anatomy & histology , Drosophila melanogaster/physiology , Dynamins/genetics , Dynamins/metabolism , GTP-Binding Protein alpha Subunits, Gq-G11/genetics , Light , Membrane Proteins/genetics , Membrane Proteins/metabolism , Phospholipase C beta/genetics , Phospholipase C beta/metabolism , Photoreceptor Cells, Invertebrate/cytology , Photoreceptor Cells, Invertebrate/metabolism , Recombinant Fusion Proteins/genetics , Recombinant Fusion Proteins/metabolism , Trans-Activators/genetics , Trans-Activators/metabolismABSTRACT
BACKGROUND: Porcine infectious pleuropneumonia caused by Actinobacillus pleuropneumoniae (App) is one of the most serious infectious diseases in pigs and has brought huge economic losses to the world pig industry. The aim of this trial was to evaluate the effect of enteric-coated tilmicosin granule in the treatment and control of artificial infection of App. METHODS: Sixty Duroc and Yorkshire crossbred pigs (50 of which were artificially infected) were divided into six groups: BCG (Blank control group), ICG (Infection-only control group), HDG (High-dose enteric-coated tilmicosin granules), MDG (Medium-dose enteric-coated tilmicosin granules), LDG (Low-dose enteric-coated tilmicosin granules) and TPG (Tilmicosin premix drug control group). The cure rate, mortality, clinical respiratory score, body temperature score, weight gain, lung score and so on were recorded. RESULTS: The cure rate of HDG and MDG was as high as 90%, the mortality was 10%, and the clinical signs recovered quickly. CONCLUSION: The results showed that enteric-coated tilmicosin granules had obvious therapeutic effect on artificial infection, which could reduce the damage caused by the disease and reduce the mortality.
Subject(s)
Actinobacillus Infections/veterinary , Actinobacillus pleuropneumoniae/drug effects , Anti-Bacterial Agents/pharmacology , Swine Diseases/drug therapy , Tylosin/analogs & derivatives , Actinobacillus Infections/drug therapy , Actinobacillus Infections/microbiology , Animals , Anti-Bacterial Agents/administration & dosage , Female , Male , Sus scrofa , Swine , Swine Diseases/microbiology , Tablets, Enteric-Coated , Tylosin/administration & dosage , Tylosin/pharmacologyABSTRACT
The Drosophila photoreceptor is a model system for genetic study of retinal degeneration. Many gene mutations cause fly photoreceptor degeneration, either because of excessive stimulation of the visual transduction (phototransduction) cascade, or through apoptotic pathways that in many cases involve a visual arrestin Arr2. Here we report a gene named tadr (for torn and diminished rhabdomeres), which, when mutated, leads to photoreceptor degeneration through a different mechanism. Degeneration in the tadr mutant is characterized by shrunk and disrupted rhabdomeres, the light sensory organelles of photoreceptor. The TADR protein interacted in vitro with the major light receptor Rh1 rhodopsin, and genetic reduction of the Rh1 level suppressed the tadr mutation-caused degeneration, suggesting the degeneration is Rh1-dependent. Nonetheless, removal of phospholipase C (PLC), a key enzyme in phototransduction, and that of Arr2 failed to inhibit rhabdomeral degeneration in the tadr mutant background. Biochemical analyses revealed that, in the tadr mutant, the G(q) protein of Rh1 is defective in dissociation from the membrane during light stimulation. Importantly, reduction of G(q) level by introducing a hypomorphic allele of G(alphaq) gene greatly inhibited the tadr degeneration phenotype. These results may suggest that loss of a potential TADR-Rh1 interaction leads to an abnormality in the G(q) signaling, which in turn triggers rhabdomeral degeneration independent of the PLC phototransduction cascade. We propose that TADR-like proteins may also protect photoreceptors from degeneration in mammals including humans.
Subject(s)
Drosophila Proteins/genetics , Drosophila/genetics , GTP-Binding Protein alpha Subunits, Gq-G11/metabolism , Genes, Insect , Retinal Degeneration/genetics , Rhodopsin/metabolism , Animals , Electroretinography , Microscopy, Electron, Transmission , Mutation , Patch-Clamp Techniques , Photoreceptor Cells, Invertebrate/metabolism , Retinal Degeneration/pathology , Reverse Transcriptase Polymerase Chain ReactionABSTRACT
OBJECTIVE: To investigate the effect and mechanism of Shenqi Fuzheng Injection (SFI) in repairing immune function of organism at cellular and molecular levels. METHODS: Seventy-seven patients with pathologically confirmed diagnosis of breast cancer were assigned to three groups, the 22 patients in group A received surgical operation only; the 26 in group B were treated with surgical operation and chemotherapy; and to the 29 in group C, both chemotherapy and SFI were given after surgical operation. Besides, a group D with 22 patients with benign tumor was set up for control. The protein expressions of CD83, CD80 and CD86 in all patients' tumor tissue and axillary lymph node were detected by flow cytometry before and after treatment. RESULTS: Levels of CD83, CD80 and CD86 in both tumor tissue and lymph node of cancer patients were significantly lower than those in the control (P < 0.05); and those in group B were significantly lower than in group A (P < 0.05, P < 0.01); but no significant difference was found in comparing the corresponding indices between group A and group C (P > 0.05). CONCLUSION: The immune function of tumor patients could be impaired by tumor and chemotherapy definitely, and SFI could give aid to the repairing of immunity by way of participating in the activation of dendritic cells and the up regulation of co-stimulus molecules.
Subject(s)
Breast Neoplasms/drug therapy , Breast Neoplasms/immunology , Drugs, Chinese Herbal/therapeutic use , Immunity/drug effects , Phytotherapy , Adult , Aged , Antigens, CD/metabolism , B7-1 Antigen/metabolism , B7-2 Antigen/metabolism , Breast Neoplasms/surgery , Carcinoma, Intraductal, Noninfiltrating/drug therapy , Carcinoma, Intraductal, Noninfiltrating/immunology , Carcinoma, Intraductal, Noninfiltrating/surgery , Female , Humans , Immunoglobulins/metabolism , Membrane Glycoproteins/metabolism , Middle Aged , CD83 AntigenABSTRACT
The transcription factor hypoxia inducible factor-1α (HIF-1α) mediates adaptive responses to oxidative stress by nuclear translocation and regulation of gene expression. Mitochondrial changes are critical for the adaptive response to oxidative stress. However, the transcriptional and non-transcriptional mechanisms by which HIF-1α regulates mitochondria in response to oxidative stress are poorly understood. Here, we examined the subcellular localization of HIF-1α in human cells and identified a small fraction of HIF-1α that translocated to the mitochondria after exposure to hypoxia or H2O2 treatment. Moreover, the livers of mice with CCl4-induced fibrosis showed a progressive increase in HIF-1α association with the mitochondria, indicating the clinical relevance of this finding. To probe the function of this HIF-1α population, we ectopically expressed a mitochondrial-targeted form of HIF-1α (mito-HIF-1α). Expression of mito-HIF-1α was sufficient to attenuate apoptosis induced by exposure to hypoxia or H2O2-induced oxidative stress. Moreover, mito-HIF-1α expression reduced the production of reactive oxygen species, the collapse of mitochondrial membrane potential, and the expression of mitochondrial DNA-encoded mRNA in response to hypoxia or H2O2 treatment independently of nuclear pathways. These data suggested that mitochondrial HIF-1α protects against oxidative stress induced-apoptosis independently of its well-known role as a transcription factor.
Subject(s)
Cytoprotection , Hypoxia-Inducible Factor 1, alpha Subunit/metabolism , Mitochondria/metabolism , Oxidative Stress , Animals , Apoptosis , Cell Hypoxia , Cell Line , DNA, Mitochondrial/genetics , Down-Regulation , Humans , Hydrogen Peroxide/metabolism , Liver Cirrhosis/metabolism , Liver Cirrhosis/pathology , Male , Membrane Potential, Mitochondrial , Mice , Mice, Inbred C57BL , Protein Transport , RNA, Messenger/genetics , RNA, Messenger/metabolism , Transcription, GeneticABSTRACT
Patients with Her2-positive breast cancer exhibit de novo resistance or develop acquired resistance in less than one year after Her2 targeting treatment, but the mechanism is not fully elucidated. Compensatory pathways such as the IGF-1R/IRS-1 pathway, are activated, leading to aberrant enhanced PI3K/Akt/mTOR pathway activity to attenuate the efficacy of trastuzumab. Cullin7 could participate in the degradation of IRS-1 in a mTOR/S6K dependent manner. Whether Cullin7 participates in trastuzumab resistance needs to be further investigated. Here, we reveals that Cullin7 is overexpressed in trastuzumab-resistant Her2 positive breast cancer cells. Knockdown of Cullin7 reduces degradation of Ser phosphorylation of IRS-1, attenuates activation of the PI3K/AKT pathway, and partly restores trastuzumab sensitivity in trastuzumab-resistant Her2 positive breast cancer cells. IGFBP-3 expression is decreased in trastuzumab-resistant Her2 positive breast cancer cells, which leads to release of the Wnt signaling pathway inhibition and an increase in Cullin7 expression, as mediated by TCF7L2. Overexpression of Cullin7 in Her2-amplified breast cancer tissues has clinical implications because it positively correlates with shorter disease-free survival (DFS) and inadequate response to trastuzumab. Thus, our results suggest a critical role for Cullin7 in response to trastuzumab, which has significant implications for selection of the optimal therapeutic strategy for Her2 positive breast cancers.