58 research outputs found

    Epothilone B Benefits Nigral Dopaminergic Neurons by Attenuating Microglia Activation in the 6-Hydroxydopamine Lesion Mouse Model of Parkinson’s Disease

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    Parkinson’s disease (PD) is characterized by loss of dopamine (DA) neurons in the substantia nigra pars compacta (SNc) and a subsequent reduction in striatal DA levels. Recent studies have shown that systemic administration of subtoxic doses of epothilone B (EpoB), a microtubule stabilizing agent, enhances axonal regeneration. However, the underlying alterations in cellular mechanisms remain undetermined. In the present study, we investigated the neuroprotective effects of EpoB on DA neurons in mouse model of PD induced by 6-hydroxyDA (6-OHDA) and in vitro. The results indicated that EpoB improved behavioral deficits, protected the nigrostriatal dopaminergic projections and restored DA level in the striatum of mice exposed to 6-OHDA. Meanwhile, EpoB attenuated microglia activation in the SNc of PD mice. Furthermore, EpoB treatment ameliorated 6-OHDA induced cytotoxicity to MN9D dopaminergic cells in a co-culture transwell system of BV2/MN9D cells, and redistributed the cytoskeleton of microglial BV2 and caused the morphological transition, inhibited the polarization to the M1 phenotype by suppressing expression of pro-inflammatory factors including interleukin (IL)-1β, IL-6 and tumor necrosis factor (TNF)-α. Overall, our study suggested that EpoB treatment protects nigral DA neurons and projections through limiting the cytotoxicity of activated microglia in 6-OHDA lesioned mice

    Novel bi-allelic variants of CHMP1A contribute to pontocerebellar hypoplasia type 8: additional clinical and genetic evidence

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    Pontocerebellar hypoplasia type 8(PCH8) is a rare neurodegenerative disorder, reportedly caused by pathogenic variants of the CHMP1A in autosomal recessive inheritance, and CHMP1A variants have also been implicated in other diseases, and yet none of the prenatal fetal features were reported in PCH8. In this study, we investigated the phenotype and genotype in a human subject with global developmental delay, including clinical data from the prenatal stage through early childhood. Prenatally, the mother had polyhydramnios, and the bilateral ventricles of the fetus were slightly widened. Postnatally, the infant was observed to have severely delayed psychomotor development and was incapable of visual tracking before 2 years old and could not fix on small objects. The young child had hypotonia, increased knee tendon reflex, as well as skeletal malformations, and dental crowding; she also had severe and recurrent pulmonary infections. Magnetic resonance imaging of the brain revealed a severe reduction of the cerebellum (vermis and hemispheres) and a thin corpus callosum. Through whole exome sequencing and whole genomics sequencing, we identified two novel compound heterozygous variations in CHMP1A [c.53 T > C(p.Leu18Pro)(NM_002768.5) and exon 1 deletion region (NC_000016.10:g.89656392_89674382del)]. cDNA analysis showed that the exon1 deletion region led to the impaired expression, and functional verification with zebrafish embryos using base edition indicated variant c.53 T > C (p.Leu18Pro), causing dysplasia of the cerebellum and pons. These results provide further evidence that CHMP1A variants in a recessive inheritance pattern contribute to the clinical characteristics of PCH8 and further expand our knowledge of the phenotype and genotype spectrum of PCH8

    Rescue of Retinal Degeneration in rd1 Mice by Intravitreally Injected Metformin

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    Retinitis pigmentosa (RP) is a progressive hereditary retinal degenerative disease in which photoreceptor cells undergo degeneration and apoptosis, eventually resulting in irreversible loss of visual function. Currently, no effective treatment exists for this disease. Neuroprotection and inflammation suppression have been reported to delay the development of RP. Metformin is a well-tested drug used to treat type 2 diabetes, and it has been reported to exert beneficial effects in neurodegenerative diseases, such as Parkinson’s disease and Alzheimer’s disease. In the present study, we used immunofluorescence staining, electroretinogram (ERG) recordings and RNA-Seq to explore the effects of metformin on photoreceptor degeneration and its mechanism in rd1 mice. We found that metformin significantly reduced apoptosis in photoreceptors and delayed the degeneration of photoreceptors and rod bipolar cells in rd1 mice, thus markedly improving the visual function of rd1 mice at P14, P18, and P22 when tested with a light/dark transition test and ERG. Microglial activation in the outer nuclear layer (ONL) of the retina of rd1 mice was significantly suppressed by metformin. RNA-Seq showed that metformin markedly downregulated inflammatory genes and upregulated the expression of crystallin proteins, which have been demonstrated to be important neuroprotective molecules in the retina, revealing the therapeutic potential of metformin for RP treatment. αA-crystallin proteins were further confirmed to be involved in the neuroprotective effects of metformin in a Ca2+ ionophore-damaged 661W photoreceptor-like cell line. These data suggest that metformin exerts a protective effect in rd1 mice via both immunoregulatory and new neuroprotective mechanisms

    Oroxylin A promotes PTEN-mediated negative regulation of MDM2 transcription via SIRT3-mediated deacetylation to stabilize p53 and inhibit glycolysis in wt-p53 cancer cells

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    Introduction p53 plays important roles in regulating the metabolic reprogramming of cancer, such as aerobic glycolysis. Oroxylin A is a natural active flavonoid with strong anticancer effects both in vitro and in vivo. Methods wt-p53 (MCF-7 and HCT116 cells) cancer cells and p53-null H1299 cancer cells were used. The glucose uptake and lactate production were analyzed using Lactic Acid production Detection kit and the Amplex Red Glucose Assay Kit. Then, the protein levels and RNA levels of p53, mouse double minute 2 (MDM2), and p53-targeted glycolytic enzymes were quantified using Western blotting and quantitative polymerase chain reaction (PCR), respectively. Immunoprecipitation were performed to assess the binding between p53, MDM2, and sirtuin-3 (SIRT3), and the deacetylation of phosphatase and tensin homolog (PTEN). Reporter assays were performed to assess the transcriptional activity of PTEN. In vivo, effects of oroxylin A was investigated in nude mice xenograft tumor-inoculated MCF-7 or HCT116 cells. Results Here, we analyzed the underlying mechanisms that oroxylin A regulated p53 level and glycolytic metabolism in wt-p53 cancer cells, and found that oroxylin A inhibited glycolysis through upregulating p53 level. Oroxylin A did not directly affect the transcription of wt-p53, but suppressed the MDM2-mediated degradation of p53 via downregulating MDM2 transcription in wt-p53 cancer cells. In further studies, we found that oroxylin A induced a reduction in MDM2 transcription by promoting the lipid phosphatase activity of phosphatase and tensin homolog, which was upregulated via sirtuin3-mediated deacetylation. In vivo, oroxylin A inhibited the tumor growth of nude mice-inoculated MCF-7 or HCT116 cells. The expression of MDM2 protein in tumor tissue was downregulated by oroxylin A as well. Conclusions These results provide a p53-independent mechanism of MDM2 transcription and reveal the potential of oroxylin A on glycolytic regulation in both wt-p53 and mut-p53 cancer cells. The studies have important implications for the investigation on anticancer effects of oroxylin A, and provide the academic basis for the clinical trial of oroxylin A in cancer patients

    Learning to Generate Urban Design Images From the Conditional Latent Diffusion Model

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    With the rapid process of computer vision and deep learning, image synthesis models, such as the latent diffusion models, have exhibited remarkable performances in producing high-quality and realistic results. However, achieving precise layout control through adjusting text prompts solely proves to be challenging for the diffusion model. Therefore, we organize the conditional control network to instruct the latent diffusion model towards generating satisfactory results. Besides, direct training from scratch or fine-tuning the latent diffusion model on new datasets is non-trivial due to massive parameters. To tackle the troublesome training problem, we implement the low-rank adaptation strategy in the training process of the diffusion model. The low-rank adaptation strategy decomposes 2-dimensional matrices into 1-dimensional vectors, which can decrease the number of parameters greatly and accelerate the training of the latent diffusion model. To synthesize high-quality images, we collect urban design images from pinterest and generate homologous text prompts. We intend to make this dataset publicly available for further research and development in the field. Both qualitative and quantitative evaluations demonstrate the effectiveness and capacity of our framework

    The complete mitogenome of Fusarium equiseti

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    The complete mitochondrial genome of plant pathogenic fungus, Fusarium equiseti, was sequenced. The circular molecule is 53,411 bp long with a GC content of 32.81%. It contains 22 protein-coding genes, 4 ribosomal RNA (rRNA), and 24 transfer RNA (tRNA) genes. Phylogenetic reconstructions confirmed that it has the closest relationship with Fusarium equiseti. The mitogenome analysis of Fusarium equiseti provides a molecular basis for further studies on molecular systematics and evolutionary dynamics

    Glioma Stem Cells-Derived Exosomes Promote the Angiogenic Ability of Endothelial Cells Through miR-21/VEGF Signal

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    Glioma stem cells (GSCs) play an important role in glioblastoma prognosis. Exosomes (EXs) mediate cell communication by delivering microRNAs (miRs). Glioblastoma has a high level of miR-21 which could upregulate vascular endothelial growth factor (VEGF) expression. We hypothesized GSC-EXs can promote the angiogenic ability of endothelial cells (ECs) through miR-21/VEGF signal. GSCs were isolated from U-251 cells with stem cell marker CD133. GSCs transfected without or with scramble or miR-21 mimics were used to produce GSC-EXscon, GSC-EXssc and GSC-EXsmiR-21. Human brain ECs were co-cultured with vehicle, GSC-EXscon, GSC-EXssc or GSC-EXsmiR-21 plus VEGF siRNAs (siRNAVEGF). After 24 hours, the angiogenic abilities of ECs were evaluated. The levels of miR-21, VEGF and p-Flk1/VEGFR2 were determined. Results showed: 1) Over 90% of purified GSCs expressed CD133; 2) The levels of miR-21 and VEGF in GSCs and GSC-EXs were up-regulated by miR-21 mimic transfection; 3) Compared to GSC-EXscon or GSC-EXssc, GSC-EXsmiR-21 were more effective in elevating the levels of miR-21 and VEGF, and the ratio of p-Flk1/VEGFR2 in ECs; 4) GSC-EXsmiR-21 were more effective in promoting the angiogenic ability of ECs than GSC-EXscon or GSC-EXssc, which were remarkably reduced by siRNAVEGF pretreatment. In conclusion, GSC-EXs can promote the angiogenic ability of ECs by stimulating miR-21/VEGF/VEGFR2 signal pathway

    Black Phosphorus Nano-Polarizer with High Extinction Ratio in Visible and Near-Infrared Regime

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    We study computationally the design of a high extinction ratio nano polarizer based on black phosphorus (BP). A scattering-matrix calculation method is applied to compute the overall polarization extinction ratio along two orthogonal directions. The results reveal that, with a resonance cavity of SiO2, both BP/ SiO 2 /Si and h-BN/BP/ SiO 2 /Si configurations can build a linear polarizer with extinction ratio higher than 16 dB at a polarized wavelength in the range of 400 nm⁻900 nm. The polarization wavelength is tunable by adjusting the thickness of the BP layer while the thicknesses of the isotrocpic layers are in charge of extinction ratios. The additional top layer of h-BN was used to prevent BP degradation from oxidation and strengthens the practical applications of BP polarizer. The study shows that the BP/ SiO 2 /Si structure, with a silicon compatible and easy-to-realize method, is a valuable solution when designing polarization functional module in integrated photonics and optical communications circuits

    Glioma Stem Cells-Derived Exosomes Promote the Angiogenic Ability of Endothelial Cells Through miR-21/VEGF Signal

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    Glioma stem cells (GSCs) play an important role in glioblastoma prognosis. Exosomes (EXs) mediate cell communication by delivering microRNAs (miRs). Glioblastoma has a high level of miR-21 which could upregulate vascular endothelial growth factor (VEGF) expression. We hypothesized GSC-EXs can promote the angiogenic ability of endothelial cells (ECs) through miR-21/VEGF signal. GSCs were isolated from U-251 cells with stem cell marker CD133. GSCs transfected without or with scramble or miR-21 mimics were used to produce GSC-EXscon, GSC-EXssc and GSC-EXsmiR-21. Human brain ECs were co-cultured with vehicle, GSC-EXscon, GSC-EXssc or GSC-EXsmiR-21 plus VEGF siRNAs (siRNAVEGF). After 24 hours, the angiogenic abilities of ECs were evaluated. The levels of miR-21, VEGF and p-Flk1/VEGFR2 were determined. Results showed: 1) Over 90% of purified GSCs expressed CD133; 2) The levels of miR-21 and VEGF in GSCs and GSC-EXs were up-regulated by miR-21 mimic transfection; 3) Compared to GSC-EXscon or GSC-EXssc, GSC-EXsmiR-21 were more effective in elevating the levels of miR-21 and VEGF, and the ratio of p-Flk1/VEGFR2 in ECs; 4) GSC-EXsmiR-21 were more effective in promoting the angiogenic ability of ECs than GSC-EXscon or GSC-EXssc, which were remarkably reduced by siRNAVEGF pretreatment. In conclusion, GSC-EXs can promote the angiogenic ability of ECs by stimulating miR-21/VEGF/VEGFR2 signal pathway
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