bluuebunny/crossref_metadata_2025_split huggingface dataset:
FUNCTIONAL CHARACTERIZATION OF THE NOVEL GENE CIA7 FROM CHLAMYDOMONAS REINHARDTII
Authors: Cantu Hector Guillermo Gonzalez , Ynalvez Ruby Agno 
Published: June 2021

Heavy metal contamination presents a constant threat to biological systems. These metals interact with the catalytic‐domain of enzymes, interfering with their normal rates of activity, as well as inducing oxidative stress. Certain microorganisms have evolved molecular mechanisms to attenuate this; one of them being the expression and synthesis of low‐molecular weight, thiol‐rich proteins, termed as phytochelatins and metallothioneins. One such organism is Chlamydomonas reinhardtii. C. reinhardtii is an excellent model organism used in studies of heavy metals due to its high endogenous tolerance. In C. reinhardtii a novel gene designated as Cia7, was isolated and was hypothesized to confer tolerance to heavy metals. This was due to CIA7's conserved Cys‐residue motif. Such motif is found in a number of metal binding proteins. In this regard, this study aimed to demonstrate what role, if any, CIA7 exerts on tolerance towards Cd2+ stress in C. reinhardtii. The hypothesis was that the expression of Cia7 will contribute, at least in part, to an increased Cd‐tolerance in C. reinhardtii, as evidenced by physiological markers of health, as well as intracellular accumulation of the metal. The discovery of gene Cia7 in C. reinhardtii may lead to the elucidation of a novel mechanism of metal tolerance or homeostasis in C. reinhardtii. To functionally characterize Cia7: (1) comparative studies of chlorophyll fluorescence and cell size in WT and cia7− in the presence of Cd2+, (2) comparative studies of Cd2+ bioaccumulation in WT and cia7−, and (3) Cd2+ tolerance assays in cia7 insertional mutants were designed. The present work reports on the findings of Cd2+ induced decreased chlorophyll fluorescence and cell size in the cia7− mutant, as well as no difference in Cd‐bioaccumulation at low (5, 10μM) Cd2+ concentrations amongst the WT and cia7−. These results indicate a possible correlation amongst cia7 expression and Cd2+ tolerance. The characterization of CIA7 as a metal‐binding protein would allow for its potential usage as a metal sequestering agent in environmental applications. This would facilitate the remediation of metal‐contaminated ecosystems, which would eliminate the risk of metal poisoning in humans. Furthermore, a correlation of heavy metal exposure to cia7 expression could designate CIA7 as a biomarker for heavy metal contamination.Support or Funding InformationCollege of Arts and Sciences and Office of Graduate StudiesThis abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Regulation of Notch Signaling by Src Kinase
Authors: LaFoya Bryce , Munroe Jordan A. , Albig Allan R. 
Published: June 2021

Notch signaling is a form of intercellular communication which plays pivotal roles at various stages in development and disease. The Notch receptor is a single‐pass transmembrane receptor which undergoes proteolytic processing upon binding with a ligand extending from an adjacent cell's membrane. This ligation and subsequent cleavage liberates the transcriptionally active intracellular domain of Notch from the full length receptor. The emancipated Notch intracellular domain undergoes nuclear translocation where it facilitates target gene transcription. Through this series of molecular events, cells can enact changes in a neighboring cell's gene expression patterns. It is now being revealed that Notch signaling has roles which extend beyond juxtacrine signal transduction. Work in our laboratory focuses on the mechanisms by which Notch signaling integrates cell‐cell stimuli with extracellular cues. In a recent publication from our laboratory, we reported that integrin signaling is capable coordinating the Notch pathway. Here, we reveal that the regulation of Notch by integrins is carried out by Src family kinases working downstream of integrins. This is achieved through the phosphorylation of tyrosine residues, within the Notch intracellular domain, by Src. While serine/threonine phosphorylation of the Notch receptor has been well characterized and is essential to important regulatory events, the tyrosine phosphorylation of the Notch receptor is a relatively unexplored area of research. We have identified four tyrosine residues within the intracellular domain of Notch1 that are phosphorylated by Src. In order to observe the functional consequences of Src induced phosphorylation of Notch1, mutagenesis was performed at these sites. We have found that phosphorylation at these residues has implications for Notch1 intracellular domain stability and transcriptional activity. In addition to this work, we have investigated a number of polyphenolic compounds which are capable of binding integrins and regulating the Notch pathway. We report on the Notch induced ramifications of cellular stimulation with resveratrol, and related polyphenols, that alter Notch target gene transcription. Having established these results, we turn our attention towards the importance of Notch‐Src interactions and polyphenolic regulation of Notch signaling as it pertains to vascular biology.Support or Funding InformationNIH 2R15GM102852‐02, NIH 2R15GM102852‐01This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Astrocyte‐derived CCL20 reinforces HIF‐1‐mediated hypoxic responses in glioblastoma by stimulating the CCR6‐NF‐kB signaling pathway
Authors: JIN Peng , Park Jong‐Wan 
Published: June 2021

During tumor development, stromal cells are co‐opted to the tumor milieu and provide favorable conditions for the tumor. Hypoxia stimulates cancer cells to acquire a more malignant phenotype via activation of hypoxia‐inducible factor 1 (HIF‐1). Given that cancer cells and astrocytes in glioblastomas coexist in a hypoxic microenvironment, we examined whether astrocytes affect the adaptation of glioblastoma cells to hypoxia. Immunoblotting, reporter assays, quantitative RT‐PCR, and chromatin immunoprecipitation were performed to evaluate HIF‐1 signaling in glioblastoma cells. Astrocyte‐derived chemokine C‐C motif ligand 20 (CCL20) was identified using cytokine arrays, and its role in glioblastoma development was evaluated in orthotopic xenografts. Astrocytes augmented HIF‐1a expression in glioblastoma cells under hypoxia. The expression of HIF‐1 downstream genes, cancer colony formation, and Matrigel invasion of glioblastoma cells were stimulated by conditioned medium from astrocytes pre‐exposed to hypoxia. CCL20 was secreted in a hypoxia‐dependent manner from astrocytes and busted the hypoxic induction of HIF‐1a in glioblastoma cells. Mechanistically, the CCL20/CCR6 signaling pathway upregulates HIF‐1a by stimulating nuclear factor kappa B‐driven transactivation of the HIF1A gene. Compared with the control tumors, CCR6‐deficient glioblastoma xenografts grew more slowly, with poor vascularization, and expressed lower levels of HIF‐1a and its downstream proteins. Furthermore, CCR6 expression was correlated with HIF‐1a expression in GEO and TCGA datasets from human glioblastoma tissues. These results suggest that glioblastoma cells adapt well to hypoxic stress by virtue of CCL20 derived from neighboring astrocytes.Support or Funding InformationThis work was supported by the National Research Foundation of Korea (2016R1A2A1A05005082). Jin received a scholarship from the BK21‐plus education program and Park JW was supported by the Education and Research Encouragement Fund of Seoul National University Hospital.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
WW Domain‐containing Oxidoreductase Induces Cellular Senescence in Response to Replication Stress
Authors: Cheng Hui‐Ching , Hsu Li‐Jin 
Published: June 2021

The induction of DNA damage response (DDR) to ensure accurate duplication of genetic information is crucial for the maintenance of cellular genome integrity during DNA replication. Under replication stress, cellular senescence is a DDR mechanism that prevents the proliferation of cells with DNA damage to avoid mitotic anomalies and inheritance of the damage over cell generations. A reduction in the ability of cells to trigger senescence has been suggested to be associated with cancer initiation and progression. Human WWOX gene resides within a common chromosomal fragile site FRA16D and encodes a tumor suppressor WW domain‐containing oxidoreductase. Downregulation of WWOX protein expression has been frequently found in various human cancers. Increased genome instability has been shown in the cells null for WWOX. However, the role of WWOX in DDR remains largely unclear. In this study, we demonstrated that Wwox gene knockout (Wwox−/−) mouse embryonic fibroblasts (MEFs) failed to undergo replication‐induced cellular senescence after multiple passages in culture. Strikingly, accelerated cell cycle progression and increased apoptosis were detected in late‐passage Wwox−/− MEFs. Increased γH2AX‐positive cells were observed in late‐passage Wwox−/− MEFs, indicating massive accumulation of DNA damages in these cells. The p16INK4A/Rb‐ and p53/p21cip1/waf1‐mediated signaling pathways have been suggested to control cellular senescence. We determined significantly reduced expression of p16INK4A and p21cip1/waf1 proteins in late‐passage Wwox−/− MEFs. Treatment of Wwox−/− MEFs with DNA methylation inhibitor 5‐aza‐2′‐deoxycytidine reversed p16INK4A and p21cip1/waf1 expression, and ectopic expression of p16INK4A and p21cip1/waf1 increased cellular senescence in late‐passage Wwox−/− MEFs. These results suggest that hypermethylation of p16INK4A and p21cip1/waf1 promoters may lead to the failure of senescence induction in Wwox−/− MEFs. Moreover, inhibition of ROS production by N‐acetyl‐L‐cysteine during cell replication in vitro increased protein expression of p16INK4A and p21cip1/waf1 and the induction of cellular senescence in Wwox−/− MEFs. In conclusion, our results support a crucial role for WWOX in DDR for maintaining genome integrity via the induction of cellular senescence in response to replication stress.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
The surreptitious survival of the opportunistic pathogen Staphylococcus lugdunensis within macrophages as an immune evasion strategy
Authors: Heinrichs David , Flannagan Ronald , Watson David 
Published: June 2021

Staphylococcus lugdunensis has acquired recognition as a relatively new and serious pathogen that is often clinically misidentified as S. aureus. To cause infection S. lugdunensis must circumvent host immunity, including the innate defenses presented by professional phagocytes such as macrophages. In this study, we demonstrate for the first time that macrophages of murine and human origin are not microbicidal towards S. lugdunensis and that phagocytosed S. lugdunensis remain viable within infected macrophages over an extended period (>24 h). Interestingly, phagocytosed S. lugdunensis, which fail to replicate, also do not intoxicate host cells, thus distinguishing the intracellular lifestyle of S. lugdunensis from that of S. aureus. Dextran pulse‐chase and LAMP‐1 immuno‐localization studies reveal that phagocytosed S. lugdunensis take up residence inside LAMP‐1‐positive phagolysosomes where the bacteria persist for at least 24 hours. Phagocytosed S. lugdunensis are modified within macrophages such that they are sensitized to in vitro stresses imposed by antimicrobial peptide treatment (e.g. polymyxin B), exposure to non‐ionic detergent (e.g. Triton‐X100), and the staphylococcal selective medium mannitol salt agar. We further demonstrate that optimal survival of S. lugdunensis requires O‐acetylated peptidoglycan since a S. lugdunensis oatA mutant, which is more sensitive to killing by lysozyme than WT, survived to a lesser extent in the phagosome. Through pharmacological disruption of lysosome function, either prior to or post phagocytosis, we demonstrate that S. lugdunensis bacteria can be coaxed into escaping the phagolysosome and replicating within both murine macrophages and primary human macrophages. Notably, however, intracellularly replicating S. lugdunensis fail to intoxicate infected macrophages as indicated by the host cells' ability to phagocytose IgG‐opsonized targets and remain refractory to vital dye staining. We propose that macrophages harboring S. lugdunensis in vivo represent a bacterial reservoir and events that disrupt macrophage function would allow these bacteria to proliferate whilst remaining protected from extracellular immune factors.Support or Funding InformationCanadian Institutes of Health ResearchThis abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Bacteria, Brains, and Behavior: gut microbes and their effects on regulation of gene expression in the brain
Authors: Horstman Cara , Devries Laura , Sonnenburg Marie , Carlson Clayton 
Published: June 2021

The purpose of this research is to investigate the relationship between the microbiota of the gastrointestinal (GI) system, behavioral characteristics related to Autism Spectrum Disorder (ASD), and relative gene expression of miRNAs in the brain. This research utilizes BALB/c mice (a mouse strain that demonstrates low sociability) as a prototype for ASD and C57BL/6 as a control group of mice. Each mouse strain is fed either Bifidiobacterium longum, Lactobacillus rhamnosus, both bacteria, or only the bacterial media as a negative control. These bacterial strains are both well characterized probiotics shown to change behavior and improve sociability. Behavioral characteristics throughout the 10‐week feeding period for both mouse strains, and each probiotic condition, are compared using Crawley's Sociability and Preference for Social Novelty protocol. Upon completion of the 10‐week study, the mice are sacrificed, the brains are harvested, and the RNA is extracted from the brains of the mice. PCR arrays (Qiagen) are performed to determine changes in the gene expression of brain‐specific miRNAs. Preliminary results from a 3‐week feeding study indicated several miRNAs of interest. For example, these results revealed that relative gene expression of mmi‐488‐3c in the BALB/c mice was substantially more similar to the miRNA's expression in C57BL/6 only following the Bifidobacterium probiotic treatment. The data set from the extended 10‐week probiotic treatment will provide more significant evidence that these GI bacterial probiotics cause changes in expression of important regulatory RNAs. The resultant consequences for target brain mRNAs will also be demonstrated. As this study continues, it aims to further close the gap of understanding between causal relationships between the gut microbiota, neurological changes, and social behavior of animals.Support or Funding InformationTrinity Christian College, Vander Velde Research Fellowship.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Attenuation of FFA‐induced skeletal muscle insulin resistance by rosemary extract
Authors: Vlavcheski Filip , Tsiani Evangelia 
Published: June 2021

Elevated blood free fatty acids (FFAs), as seen in obesity, impair insulin action in muscle leading to insulin resistance and Type 2 diabetes mellitus. Serine phosphorylation of the insulin receptor substrate (IRS) reduces insulin‐stimulated tyrosine phosphorylation leading to insulin resistance. A number of serine/threonine kinases including JNK, mTOR and p70 6SK have been implicated in serine phosphorylation of IRS‐1 and insulin resistance. Activation of the energy sensor AMP‐activated protein kinase (AMPK) increases glucose uptake and has become an important target to counteract insulin resistance. We reported recently that rosemary extract (RE) increased skeletal muscle cell glucose uptake and activated AMPK. However, its effect on FFA‐induced insulin resistant muscle cells has never been elucidated. In this study, we investigated the effect of RE in palmitate‐induced insulin resistant L6 muscle cells. Glucose uptake was measured using [3H]‐2‐deoxy‐D‐glucose and the signaling molecules involved were investigated by immunoblotting.Exposure of L6 myotubes to the FFA palmitate (P) (0.2 mM, 16 hours) resulted in significant reduction in insulin‐stimulated glucose uptake (I: 201±1.21% and P+I: 117±15.6% of control, P<0.001 respectively) indicating insulin resistance. Importantly, exposure to RE resulted in significant restoration of insulin‐stimulated glucose uptake (179±10.5% of control, P<0.001). Treatment with palmitate increased serine phosphorylation of IRS‐1 and significantly decreased the insulin‐stimulated phosphorylation of Akt and these effects were completely abolished in the presence of RE. Treatment with palmitate increased the phosphorylation/activation of JNK, mTOR and p70 6SK whereas RE completely abolished these effects. RE increased the phosphorylation of AMPK even in the presence of palmitate. Overall, our data indicate that treatment with RE attenuates the FFA‐induced insulin resistance. RE and RE polyphenols may have potent effects against insulin resistance and deserve further study.Support or Funding InformationSupported by a Natural Sciences and Engineering Research Council of Canada (NSERC) grant to ET.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Protective effects of perilla seed meal on tert‐butyl hydroperoxide induced oxidative damage in HepG2 cells
Authors: Sim Ung , Kim In‐Hwan , Lee Junsoo 
Published: June 2021

This study aimed to evaluate the protective effect of methanol extract of perilla seed meal (PSE) against oxidative stress induced by tert‐butylhydroperoxide (t‐BHP) in HepG2 cells. The total phenolics and flavonoid contents of PSE were 41.36 ± 1.00 mg gallic acid equivalents/g of residue and 38.20 ± 0.17 mg catechin equivalents/g of residue, respectively. Quantitative analysis of the major constituent phenolic acids and tocopherols was achieved by using high‐performance liquid chromatography. PSE (10–100 μg/mL) pretreatment significantly prevented t‐BHP‐induced cytotoxicity in HepG2 cells. Oxidative damage induced by t‐BHP was accompanied by glutathione depletion, ROS generation, and lipid peroxidation, which were all significantly ameliorated by PSE. The cytoprotective effect of PSE was attributed to the modulation of cellular antioxidant defense enzymes such as glutathione peroxidase, superoxide dismutase, glutathione reductase, and catalase. Collectively, the bioactive compounds of PSE were able to prevent oxidative stress through the enhancement of the antioxidant indices.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Syntaxin 4 (STX4)‐ More than just a SNARE protein: Elevating STX4 content in skeletal muscle to prevent insulin resistance/pre‐diabetes
Authors: Merz Karla Elzein , Olson Erika , Zhang Jing , Veluthakal Raja , Oh Eunjin , Hamilton Angelica , Huss Janice , Thurmond Debbie C. 
Published: June 2021

Type 2 diabetes results from a combination of peripheral insulin resistance plus insulin secretion defects. Insulin resistance is characterized by a failure of skeletal muscle to clear excess blood glucose from the circulation, and is central to what is commonly called ‘pre‐diabetes'. While type 2 diabetes afflicts ~10% of the US population, pre‐diabetes is estimated to impact more than a third of our population. Over 80% of glucose clearance occurs via the skeletal muscle, there are no directed therapeutics to restore its function in pre‐diabetics. Several studies have identified correlations between insulin resistance and reduced levels of a SNARE protein named Syntaxin 4 (STX4) in human skeletal muscle. STX4 interacts with other SNARE proteins to facilitate the fusion of glucose transporter 4 (GLUT4) vesicles with the plasma membrane, to then channel extracellular glucose to the interior of the muscle cell, ultimately ‘clearing glucose’ from the circulation. Towards understanding how STX4 content is regulated in muscle, we mimicked the pre/diabetic milieu of high glucose and high lipid content in the L6‐GLUT4myc skeletal muscle cells and demonstrated the same STX4 depletion reported in the human studies. Having established this model system, we next assessed the potential for STX4 overexpression to prevent insulin resistance, and found STX4‐overexpressing cells show less Annexin V and Propidium iodide staining compared with sham‐transfected cells, suggesting that STX4 overexpression exerted a protective effect against diabetogenic stimuli‐induced apoptosis. To next test this in vivo, we have developed an inducible skeletal muscle specific STX4 overexpressing mouse model. Remarkably, under standard non‐diabetogenic conditions, female mice overexpressing STX4 show heightened glucose tolerance and insulin sensitivity compared to control mice. Whether STX4‐overexpressing mice are protected from obesity‐induced insulin resistance, or perhaps whether STX4 upregulation in already‐obese mice might reverse insulin resistance and through which mechanism, are questions currently under pursuit. Taken together, these results suggest that STX4 functions in the skeletal muscle to facilitate glucose uptake function and to protect myocytes from diabetogenic stress induced apoptosis. This suggests that STX4 could be a viable therapeutic target for treatment and prevention of pre‐diabetes.Support or Funding InformationThis research was supported by the National Institutes of Health (DK067912, DK102233) to D.C.T. and also by the H.N. & Frances C. Berger Foundation Fellowship to K.MThis abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.