scholarly journals Synaptic mutant huntingtin inhibits synapsin-1 phosphorylation and causes neurological symptoms

2013 ◽  
Vol 202 (7) ◽  
pp. 1123-1138 ◽  
Author(s):  
Qiaoqiao Xu ◽  
Shanshan Huang ◽  
Mingke Song ◽  
Chuan-En Wang ◽  
Sen Yan ◽  
...  
Keyword(s):  
Neurotransmitter Release ◽  
Critical Role ◽  
Early Death ◽  
Neurological Symptoms ◽  
Mass Spectrometry Analysis ◽  
Mutant Huntingtin ◽  
Cellular Functions ◽  
Spectrometry Analysis ◽  
Knockin Mouse ◽  
Synapsin 1

Many genetic mouse models of Huntington’s disease (HD) have established that mutant huntingtin (htt) accumulates in various subcellular regions to affect a variety of cellular functions, but whether and how synaptic mutant htt directly mediates HD neuropathology remains to be determined. We generated transgenic mice that selectively express mutant htt in the presynaptic terminals. Although it was not overexpressed, synaptic mutant htt caused age-dependent neurological symptoms and early death in mice as well as defects in synaptic neurotransmitter release. Mass spectrometry analysis of synaptic fractions and immunoprecipitation of synapsin-1 from HD CAG150 knockin mouse brains revealed that mutant htt binds to synapsin-1, a protein whose phosphorylation is critical for neurotransmitter release. We found that polyglutamine-expanded exon1 htt binds to the C-terminal region of synapsin-1 to reduce synapsin-1 phosphorylation. Our findings point to a critical role for synaptic htt in the neurological symptoms of HD, providing a new therapeutic target.

scholarly journals Inositol monophosphatase 1 as a novel interacting partner of RAGE in pulmonary hypertension

2019 ◽  
Vol 316 (3) ◽  
pp. L428-L444 ◽  
Author(s):  
Ruslan Rafikov ◽  
Matthew L. McBride ◽  
Marina Zemskova ◽  
Sergey Kurdyukov ◽  
Nolan McClain ◽  
...  
Keyword(s):  
Vascular Remodeling ◽  
Critical Role ◽  
Systolic Pressure ◽  
Akt Signaling ◽  
Mass Spectrometry Analysis ◽  
Proximity Ligation Assay ◽  
Sprague Dawley ◽  
Spectrometry Analysis ◽  
Akt Phosphorylation ◽  
Threefold Increase

Pulmonary arterial hypertension (PAH) is a lethal disease characterized by progressive pulmonary vascular remodeling. The receptor for advanced glycation end products (RAGE) plays an important role in PAH by promoting proliferation of pulmonary vascular cells. RAGE is also known to mediate activation of Akt signaling, although the particular molecular mechanism remains unknown. This study aimed to identify the interacting partner of RAGE that could facilitate RAGE-mediated Akt activation and vascular remodeling in PAH. The progressive angioproliferative PAH was induced in 24 female Sprague-Dawley rats ( n = 8/group) that were randomly assigned to develop PAH for 1, 2, or 5 wk [right ventricle systolic pressure (RVSP) 56.5 ± 3.2, 63.6 ± 1.6, and 111.1 ± 4.5 mmHg, respectively, vs. 22.9 ± 1.1 mmHg in controls]. PAH triggered early and late episodes of apoptosis in rat lungs accompanied by RAGE activation. Mass spectrometry analysis has identified IMPA1 as a novel PAH-specific interacting partner of RAGE. The proximity ligation assay (PLA) confirmed the formation of RAGE/IMPA1 complex in the pulmonary artery wall. Activation of IMPA1 in response to increased glucose 6-phosphate (G6P) is known to play a critical role in inositol synthesis and recycling. Indeed, we confirmed a threefold increase in G6P ( P = 0.0005) levels in lungs of PAH rats starting from week 1 that correlated with accumulation of phosphatidylinositol (3,4,5)-trisphosphate (PIP3), membrane translocation of PI3K, and a threefold increase in membrane Akt levels ( P = 0.02) and Akt phosphorylation. We conclude that the formation of the newly discovered RAGE-IMPA1 complex could be responsible for the stimulation of inositol pathways and activation of Akt signaling in PAH.

scholarly journals Microbially mediated reduction of FeIII and AsV in Cambodian sediments amended with 13C-labelled hexadecane and kerogen

2014 ◽  
Vol 11 (5) ◽  
pp. 538 ◽  
Author(s):  
Athanasios Rizoulis ◽  
Wafa M. Al Lawati ◽  
Richard D. Pancost ◽  
David A. Polya ◽  
Bart E. van Dongen ◽  
...  
Keyword(s):  
Organic Matter ◽  
Critical Role ◽  
Stable Isotope Probing ◽  
Mass Spectrometry Analysis ◽  
Gas Chromatography Mass Spectrometry ◽  
Organic Substrates ◽  
Spectrometry Analysis ◽  
Subsurface Sediments ◽  
Extractable Organic Matter ◽  
Long Chain

Environmental context The use of groundwater with elevated concentrations of arsenic for drinking, cooking or irrigation has resulted in the worst mass poisoning in human history. This study shows that organic compounds that can be found in arsenic rich subsurface sediments may be used by indigenous microorganisms, contributing to the release of arsenic from the sediments into the groundwater. This study increases our understanding of the range of organic substrates (and their sources) that can potentially stimulate arsenic mobilisation into groundwaters. Abstract Microbial activity is generally accepted to play a critical role, with the aid of suitable organic carbon substrates, in the mobilisation of arsenic from sediments into shallow reducing groundwaters. The nature of the organic matter in natural aquifers driving the reduction of AsV to AsIII is of particular importance but is poorly understood. In this study, sediments from an arsenic rich aquifer in Cambodia were amended with two 13C-labelled organic substrates. 13C-hexadecane was used as a model for potentially bioavailable long chain n-alkanes and a 13C-kerogen analogue as a proxy for non-extractable organic matter. During anaerobic incubation for 8 weeks, significant FeIII reduction and AsIII mobilisation were observed in the biotic microcosms only, suggesting that these processes were microbially driven. Microcosms amended with 13C-hexadecane exhibited a similar extent of FeIII reduction to the non-amended microcosms, but marginally higher AsIII release. Moreover, gas chromatography–mass spectrometry analysis showed that 65% of the added 13C-hexadecane was degraded during the 8-week incubation. The degradation of 13C-hexadecane was microbially driven, as confirmed by DNA stable isotope probing (DNA-SIP). Amendment with 13C-kerogen did not enhance FeIII reduction or AsIII mobilisation, and microbial degradation of kerogen could not be confirmed conclusively by DNA-SIP fractionation or 13C incorporation in the phospholipid fatty acids. These data are, therefore, consistent with the utilisation of long chain n-alkanes (but not kerogen) as electron donors for anaerobic processes, potentially including FeIII and AsV reduction in the subsurface.

Impact and mechanistic role of MicroRNA-1291 on pancreatic tumorigenesis.

2016 ◽  
Vol 34 (4_suppl) ◽  
pp. 243-243 ◽  
Author(s):  
Mei-Juan Tu ◽  
Yu-Zhuo Pan ◽  
Jing-Xin Qiu ◽  
Edward Jae-hoon Kim ◽  
Aiming Yu
Keyword(s):  
Cell Cycle ◽  
Cancer Biology ◽  
Critical Role ◽  
Experimental Studies ◽  
Mass Spectrometry Analysis ◽  
Ductal Adenocarcinoma ◽  
Luciferase Reporter ◽  
Spectrometry Analysis

243 Background: Pancreatic ductal adenocarcinoma (PDAC) is the fourth leading cause of cancer death. Better understanding of pancreatic cancer biology and identification of new targets are highly warranted. MicroRNAs (miRs or miRNAs) play a critical role in the control of tumor progression via crosstalk with cancer signaling pathways. Our recent studies showed that miR-1291 improved chemosensitivity through targeting of efflux transporter ABCC1. This current study investigated the mechanistic role of miR-1291 in the suppression of pancreatic tumorigenesis. Methods: PANC-1 and AsPC-1 cell lines were stably transfected with miR-1291. Cell cycle status and apoptosis of stable miR-1291-expressing cells were tested against control cells using flow cytometry. Cells were injected subcutaneously into nude mice and tumorigenesis was measured in vivo. Proteomic studies were performed by two-dimensional difference gel electrophoresis, matrix-assisted laser desorption/ionization time of flight mass spectrometry analysis. Computationally predicted miR-1291 targets were assessed by luciferase reporter assay and Western blot. Primary PDAC and control samples were tested for miR-1291 and target gene expression levels. Results: Our data showed that stable miR-1291-expressing PANC-1 and AsPC-1 cells both showed a significantly lower rate of proliferation than the control cells, which was associated with a cell cycle arrest and enhanced apoptosis. Furthermore, miR-1291 suppressed the tumorigenesis of PANC-1 cells in mouse models in vivo. Proteomic studies revealed the protein level of several cancer-related genes were downregulated by miR-1291, including a pancreatic tumor promoting protein AGR2 which was reduced ~10-fold. Through computational and experimental studies we further identified that FOXA2, a transcription factor governing AGR2 expression, was a direct target of miR-1291. In addition, we found a significant down-regulation of miR-1291 in a set of PDAC patient tumor samples overexpressing AGR2. Conclusions: These results indicate that miR-1291 suppresses pancreatic tumorigenesis via targeting of FOXA2-AGR regulatory pathway providing new insight supporting development of miR-1291-based therapy for PDAC.

scholarly journals A reverse signaling pathway downstream of Sema4A controls cell migration via Scrib

2016 ◽  
Vol 216 (1) ◽  
pp. 199-215 ◽  
Author(s):  
Tianliang Sun ◽  
Lida Yang ◽  
Harmandeep Kaur ◽  
Jenny Pestel ◽  
Mario Looso ◽  
...  
Keyword(s):  
Cell Migration ◽  
Signaling Pathway ◽  
Large Family ◽  
Mass Spectrometry Analysis ◽  
Cellular Functions ◽  
Spectrometry Analysis ◽  
Reverse Signaling ◽  
Downstream Effector ◽  
Guanosine Triphosphatase ◽  
Interfering Rna

Semaphorins comprise a large family of ligands that regulate key cellular functions through their receptors, plexins. In this study, we show that the transmembrane semaphorin 4A (Sema4A) can also function as a receptor, rather than a ligand, and transduce signals triggered by the binding of Plexin-B1 through reverse signaling. Functionally, reverse Sema4A signaling regulates the migration of various cancer cells as well as dendritic cells. By combining mass spectrometry analysis with small interfering RNA screening, we identify the polarity protein Scrib as a downstream effector of Sema4A. We further show that binding of Plexin-B1 to Sema4A promotes the interaction of Sema4A with Scrib, thereby removing Scrib from its complex with the Rac/Cdc42 exchange factor βPIX and decreasing the activity of the small guanosine triphosphatase Rac1 and Cdc42. Our data unravel a role for Plexin-B1 as a ligand and Sema4A as a receptor and characterize a reverse signaling pathway downstream of Sema4A, which controls cell migration.

scholarly journals Klotho Exerts an Emerging Role in Cytokinesis

Genes ◽  
2020 ◽  
Vol 11 (9) ◽  
pp. 1048
Author(s):  
Chiao-Yin Sun ◽  
Chi-Yuan Chou ◽  
Yu-Ying Hsieh ◽  
Kang-Chieh Lo ◽  
Yan-Liang Liou ◽  
...  
Keyword(s):  
Spatial Correlation ◽  
Cell Model ◽  
Critical Role ◽  
Aurora Kinase ◽  
Early Embryo ◽  
Mass Spectrometry Analysis ◽  
Zebrafish Embryos ◽  
Zebrafish Model ◽  
Aurora Kinase B ◽  
Spectrometry Analysis

The Klotho gene functions as an anti-aging gene. A previous klotho-knockout mice study indicated that neither male nor female gametocytes could accomplish the first meiotic division. It suggested that Klotho might regulate cell division. In this study, we determined the roles of Klotho in cytokinesis in cultural human cells (HEK293 and HeLa) and in zebrafish embryos. Immunoprecipitation, mass spectrometry analysis, and a zebrafish model were used in this study. The results showed that Klotho is located in the midbody, which correlated with cytokinesis related kinases, Aurora kinase B and citron kinases, in the late stage of cytokinesis. There was a spatial correlation between the abscission site and the location of Klotho in the cytokinesis bridge. A three-dimensional structural reconstruction study demonstrated there was a spatial correlation among Klotho, Aurora kinase B, and citron kinases in the midbody. In addition, Klotho depletion inactivated Aurora kinases; it was also indicated that Klotho depletion caused aberrant cell cycle and delayed cytokinesis in a cell model. The study with zebrafish embryos suggested that klotho knockdown caused early embryo development abnormality due to dysregulated cytokinesis. In conclusion, Klotho might have a critical role in cytokinesis regulation by interacting with the cytokinesis related kinases.

The role of mass spectrometry analysis in bacterial effector characterization

2017 ◽  
Vol 474 (16) ◽  
pp. 2779-2784 ◽  
Author(s):  
Nichollas E. Scott ◽  
Elizabeth L. Hartland
Keyword(s):  
Mass Spectrometry ◽  
Cell Biology ◽  
Critical Role ◽  
Effector Proteins ◽  
Mass Spectrometry Analysis ◽  
Protein Activity ◽  
Post Translational Modifications ◽  
Spectrometry Analysis ◽  
New Generation

Many secreted bacterial effector proteins play a critical role in host–pathogen interactions by mediating a variety of post-translational modifications, some of which do not occur natively within the eukaryotic proteome. The characterization of bacterial effector protein activity remains an important step to understanding the subversion of host cell biology during pathogen infection and although molecular biology and immunochemistry remain critical tools for gaining insights into bacterial effector functions, increasingly mass spectrometry (MS) and proteomic approaches are also playing an indispensable role. The focus of this editorial is to highlight the strengths of specific MS approaches and their utility for the characterization of bacterial effector activity. With the capability of new generation MS instrumentation, MS-based technologies can provide information that is inaccessible using traditional molecular or immunochemical approaches.

Spectrophotometry Measurement of Polynuclear Aromatic Hydrocarbons in Hamilton Harbour Sediments

1991 ◽  
Vol 26 (1) ◽  
pp. 1-16 ◽  
Author(s):  
T.P. Murphy ◽  
H. Brouwer ◽  
M.E. Fox ◽  
E. Nagy
Keyword(s):  
Aromatic Hydrocarbons ◽  
Total Concentration ◽  
Coal Tar ◽  
Sediment Cores ◽  
Polynuclear Aromatic Hydrocarbons ◽  
Mass Spectrometry Analysis ◽  
Gas Chromatography Mass Spectrometry ◽  
Near Surface ◽  
Spectrometry Analysis ◽  
Hamilton Harbour

Abstract Eighty-one sediment cores were collected to determine the extent of coal tar contamination in a toxic area of Hamilton Harbour. Over 800 samples were analyzed by a UV spectrophotometric technique that was standardized with gas chromatography/mass spectrometry analysis. The coal tar distribution was variable. The highest concentrations were near the Stelco outfalls and the Hamilton-Wentworth combined sewer outfalls. The total concentration of the 16 polynuclear aromatic hydrocarbons (PAHs) in 48,300 m3 of near-surface sediments exceeded 200 µg/g.

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