bluuebunny/crossref_metadata_2025_split huggingface dataset:
MyoD and Myogenin are Required for Agrin‐induced AChR Clustering
Authors: Anderson Erica E. , Grow Wade A. 
Published: June 2021

During skeletal muscle development, specific transcription factors called myogenic regulatory factors are expressed at specific times to guide myogenesis. Gene expression of MyoD correlates with myoblast proliferation, while gene expression of Myogenin correlates with myoblast fusion into multinucleated myotubes and subsequent muscle fiber differentiation. Our lab investigates myogenesis and neuromuscular synapse formation using the C2C12 myotube cell culture model. C2C12 myoblasts proliferate in growth medium, and then fuse into myotubes when switched to low‐serum differentiation medium (DM) for 72 hours. Myotubes are stimulated to cluster acetylcholine receptors (AChRs) by the addition of agrin for the last 16 hours in DM. Our hypothesis was that Myogenin, but not MyoD, is required for agrin‐induced AChR clustering. Daily exposure to 1 ug/ml of MyoD antibody (Ab) or Myogenin Ab was sufficient to decrease agrin‐induced AChR clustering. In addition, exposure to 1 ug/ml of MyoD Ab or Myogenin Ab limited to the first or second 24 hours in DM also decreased agrin‐induced AChR clustering. However, agrin‐induced AChR clustering was unaffected by exposure to MyoD Ab or Myogenin Ab exposure during the last 24 hours in DM. We conclude that both MyoD and Myogenin are required for agrin‐induced AChR clustering.Grant Funding Source : None
Localization of gamma‐secretase subunit Aph‐1 in the central nervous system of Alzheimer's disease mouse model
Authors: He Guiqiong , Sun Shanquan 
Published: June 2021

The gamma‐secretase complex cleaves the final step of amyloid protein precursor (APP) to generate amyloid beta peptide (Abeta), a pathogenic component of senile plaques (SP) in the brain of Alzheimer's disease (AD). Recent studies show that Aph‐1 along with presenilins (PS), nicastrin, Pen‐2 are essential components of the gamma‐secretase. The structure and function of Aph‐1 in vitro are well defined, but less is known about its localization in the central nervous system (CNS) of AD model mice. Using Western blot and immunohistochemical methods, we found that APH‐1 is widely expressed at select neuronal populations of major areas (including cortex, hippocampus, olfactory bulb, hypothalamus, striatum, cerebellum, brainstem and spinal cord) in both APP/PS1 double transgenic AD model mice and its wildtype controls. The Aph‐1 expression level is relatively high in the brain at the early stages of postnatal development, but declined gradually to reach adult profiles in both AD and control mice. Aph‐1 is distributed much more extensively than circumscribed SP in AD mice. Aph‐1 expression level is higher than that in control mice. The present study provides an anatomical basis for indicating that APH‐1 is tightly related to AD pathogenesis.This work was supported by National Natural Science Foundation of China (30700885), Key project of Chinese Ministry of Education(209102
Disregulated Sphk1, Sphk2 and their receptors in the brain of MPTP‐induced mouse model of Parkinson's disease
Authors: sivasubramanian meenalochani , Dheen S Thameem , Peng Zhao Feng , Srinivasan Dinesh Kumar , Tay Samuel SW 
Published: June 2021

Sphingosine kinase (sphk) is a key enzyme responsible for phosphorylating sphingosine into sphingosine‐1‐phosphate(S1P). There are two forms of sphingokinases, Sphk1 and Sphk2. Sphingokinases in the nervous system control several signaling pathways involved in neuronal survival. In many neurodegenerative diseases, sphingolipid metabolism is highly disregulated. The present study demonstrates that the mRNA expression of Sphk1(a key enzyme of the sphingolipid metabolic pathway), its isoform Sphk2 and their five GPCRS (five G protein coupled receptors which are involved in the sphingolipid pathway) in dopaminergic neurons of the substantia nigra of the brain showed a marked decrease in the MPTP‐ induced mouse model of Parkinson's disease. Their downregulation was confirmed in MPP iodide‐treated MN9D cell line which contains dopaminergic neurons. Remarkably, the downregulation of these two sphingokinases was accompanied by a marked increase in the expression of TNF alpha. These results suggest that sphingolipid metabolism is altered in the substantia nigra of MPTP‐induced mouse model of Parkinson's disease. Relevance of these changes in the pathogenesis of Parkinson's disease will be discussed.Supported by grant no : MOE 2009‐T2‐1‐061 from the Ministry of Education, Singapore.
Potent Suppressive Effect of Resveratrol and Apigenin on Pro‐Inflammatory Responses in Lipopolysaccharide and IFN‐γ‐activated Microglia and Macrophages: Implications for Alzheimer's disease therapies
Authors: Ooi Lezanne 
Published: June 2021

PurposeActivation of microglia and macrophages contribute to neuroinflammation and neurotoxicity in Alzheimer's disease. However, microglia and macrophages differ in their ability to induce immune responses. Understanding the differences in the release of pro‐inflammatory factors by microglia and macrophage cells is important for identifying potential drugs to treat disease.MethodsRAW macrophages, C8B4 microglia and primary murine microglia cells were activated with lipopolysaccharide (LPS) with interferon‐γ (IFN‐γ) and levels of 23 cytokines were measured using a cytokine array. Further to this, the cells were treated with resveratrol and apigenin, anti‐inflammatories suggested as potential anti‐neurodegenerative drugs, and nitrite levels measured as a marker of oxidative stress.ResultsLPS and IFN‐γ increased nitrite levels 13 fold in RAW and 3 fold in microglia. RAW activation resulted in greater release of cytokines, such as IL‐10, whereas microglia showed greater release of chemokines, such as eotaxin. Furthermore treatment with 25 μg/ml resveratrol or 35 μg/ml apigenin lead to a 50% decrease in nitrite levels.ConclusionMicroglia and macrophages respond to activation by releasing distinct cytokine profiles. A potent suppressive effect of resveratrol and apigenin on pro‐inflammatory responses suggests a therapeutic potential for these compounds in neurodegenerative diseases.Grant Funding Source : University of Western Sydney
Effects of daidzein on post‐stroke injury and recovery of function in the rat
Authors: Stout Jessica M , Wallace Douglas G , Cheatwood Joseph L 
Published: June 2021

Treatments to reduce negative outcomes associated with stroke and/or improve functional recovery are needed. A recent study from our laboratory demonstrated the ability of a soy protein‐based diet to decrease the severity of post‐stroke behavioral deficits when provided before the onset of stroke. One potential contributor to the observed effects is daidzein, a bioactive isoflavone found in soy foods. In the current study, we aimed to determine the effectiveness of daidzein as a post‐stroke treatment and its ability to produce protective effects in the brain which may lead to enhanced behavioral recovery after stroke. To test this hypothesis, young adult male rats underwent a middle cerebral artery occlusion (MCAO) to produce a stroke lesion. Immediately after the MCAO procedure, rats were treated with either daidzein or vehicle via subcutaneous osmotic minipumps. Forelimb function was assessed using the skilled ladder rung walking task to determine post‐stroke behavioral effects and gauge functional recovery in all groups. In addition, gross locomotor performance was analyzed using the accelerating rotarod walking task. No significant difference was detected in rotarod performance between groups, although a possible trend was noted. Analyses of stroke lesion volume, skilled ladder rung walking data, and neuronal survival are ongoing. Supported by: SIUC REACH program, SIUC School of MedicineGrant Funding Source : None
Genetic association of SIX1 gene variants and primary open‐angle glaucoma in Caucasians
Authors: Shaw Robert , Wang Ye , Chen Yuhong , Du Hongjn , Zhang Kang 
Published: June 2021

Primary open‐angle glaucoma (POAG) is a condition of disorders that have optic nerve damage and slow progressive degeneration of retina ganglion cells, causing irreversible defects in the visual field loss usually associated with elevated intraocular pressure (IOP). The exact mechanism for the pathogenesis of POAG is still largely unknown. However, studies have shown that POAG has a multifactorial etiology, including genetics, high IOP and central corneal thickness (CCT). Recently, genome‐wide association study (GWAS) identified a common variant (rs10483727) on chromosome 14q22.3‐q23 within 40kbp of the SIX1 gene significantly associated with vertical cup‐disc ratio (VCDR), a parameter in the clinical assessment of the glaucoma management. To investigate the association of SIX1 gene variants with POAG, we genotyped a Caucasian cohort with 768 cases and 815 age and ethnicity matched controls. For the four SNPs we tested near SIX1 gene, we found that rs10483727 showed significant association with POAG in the Caucasian cohort (p = 9.82 × 10–6 for an additive model, OR =1.37 (1.19 – 1.59); T allele: 45.4% in cases versus 37.7% in controls). To confirm our association study result, we induced a mechanical injury to the axon by optic nerve crush in mice and found the expression of SIX1 was increased in nerve injured mice.This study was supported by grants from NIH/NEI to KZ.
Cosmc Is Silenced in Human Tn4 B Cells through Hypermethylation of the Gene Promoter
Authors: Ju Tongzhong , Mi Rongjuan , Song Lina , Wang Yingchun , Ding Xiaokun , Crew Vanja K. , Lehoux Sylvain D. , van Die Irma , Chapman Arlene B. , Cummings Richard D. 
Published: June 2021

BackgroundMucin‐type O‐glycosylation is regulated through core 1 β3‐galatosyltransferase (T‐synthase) and its specific molecular chaperone Cosmc. Human Cosmc is encoded by its gene on Xq24. Genetic alterations of Cosmc, including point mutations and gene deletions, have been identified in several human diseases. Tn4 B cells from patient with Tn‐syndrome‐like features have no transcript of Cosmc and express the Tn antigen (GalNAcα1‐Ser/Thr).Study ObjectiveTo elucidate the molecular mechanism as to how human Tn4 B cells lack Cosmc transcripts.MethodsTreat Tn4 B cells with 5‐Aza‐2′‐deoxycytidine (5‐Aza‐CdR) to test whether it can induce expression of Cosmc; and perform bisulfite sequencing to examine the methylation status of the Cosmc promoter.ResultsTreatment of Tn4 B cells with 5‐Aza‐CdR results in expression of Cosmc transcripts, restores the activity of T‐synthase, and correct the O‐glycosylation. Bisulfite sequencing showed that CG dinucleotides in the Cosmc promoter in Tn4 B cells are exclusively methylated. Interestingly, other X‐linked genes, OGT and PIG‐A are not silenced in the Tn4 B cells.ConclusionHypermethylation of the Cosmc promoter can completely silence the gene, which is another mechanism that can lead to expression of Tn and STn antigens, which may shed the light on our better understanding of the epigenetic alteration leading to the tumor antigen expression in human tumors.
PKCδ Regulates MCP‐1 Expression at the Transcription Level in Vascular Smooth Muscle Cells
Authors: Ren Jun , Morgan Stephanie , Si Yi , Liu Bo 
Published: June 2021

Monocyte chemoattractant proerin 1 (MCP‐1) is upregulated in injured arteries and has been implicated in vascular inflammation and intimal hyperplasia. We have previously shown that protein kinase C δ (PKCδ) is upregulated in smooth muscle cells (SMCs) of injured arteries. The purpose of this study is to determine whether and how PKCδ regulates MCP‐1 expression. Using SMCs isolated from mouse aortic arteries, we showed that wildtype cells responded to TNFα (10 ng/ml) with rapid increase in MCP‐1 mRNA (29.00±2.56 fold, n=4, p<0.05), an induction that was significantly diminished by PKCδ gene deficiency (11.58±1.65 fold, n=4, p<0.05). Conversely, overexpressing PKCδ by adenovirus in SMCs significantly induced MCP‐1 mRNA expression (3.57±0.27 fold, n=3, p<0.05) and protein secretion (5.79±0.05 fold, n=3, p<0.05) as compared to AdNull (empty viral vector) infected SMCs. To test whether PKCδ modulates MCP‐1 mRNA stability, we blocked gene transcription with actinomycin D followed by the TNFα treatment. The level of MCP‐1 mRNA declined in control SMCs and SMCs treated with the PKCδ inhibitor rottlerin at a similar rate, with a half‐life around 60 min (n=3). In sum, our data suggest that PKCδ regulates MCP‐1 expression in arterial SMCs, likely at the transcription level rather than by increasing its mRNA stability.This work was supported by NIH grant R01HL088447‐01A2 (to B. Liu).
Functional redundancy between Cdc20 ubiquitination and p31comet
Authors: Jia Luying , Li Bing , Warrington Ross , Hao Xing , Wang Shixuan , Yu Hongtao 
Published: June 2021

The spindle checkpoint senses unattached kinetochores in a mitotic cell, and inhibits the function of Cdc20, the mitotic activator of the anaphase‐promoting complex or cyclosome (APC/C), thus delaying anaphase onset. Upon checkpoint activation, unattached kinetochores recruit checkpoint proteins and produce diffusible APC/C‐inhibitory signals. The mitotic checkpoint complex (MCC) consisting of BubR1 (Mad3 in yeast), Bub3, Mad2, and Cdc20 is a critical checkpoint inhibitor of APC/C. When all kinetochores achieve proper microtubule attachment and are under tension, the spindle checkpoint turns off and MCC disassembles to allow APC/C activation. Several mechanisms have been implicated in MCC disassembly, including p31comet‐and UbcH10‐dependent Cdc20 autoubiquitination and proteasomal degradation. However, the role of Cdc20 autoubiquitination in checkpoint inactivation has remained controversial, because preventing Cdc20 ubiquitination by mutating all lysines in Cdc20 to arginines does not prevent MCC disassembly.In this study, we have further investigated the roles and coordination of p31comet, proteasomal degradation, and Cdc20 ubiquitination in MCC disassembly. We show that both the proteasome and p31comet are required for timely MCC disassembly in HeLa cells by treatment of proteasome inhibitor MG132 or RNA interference (RNAi). Depletion of p31comet further delays MCC disassembly in cells treated with MG132, suggesting that p31comet has a proteasome‐independent role. Consistently, p31comet depletion delays Mad2–Cdc20 dissociation and mitotic exit in cells expressing Cdc20 mutants deficient for autoubiquitination. Taken together, our results reconcile earlier conflicting data, and suggest p31comet and Cdc20 ubiquitination act in somewhat redundant pathways to promote MCC disassembly.
Integrating undergraduate research/research training into the curriculum at a minority‐serving institution
Authors: Andraos-Selim Cecile 
Published: June 2021

In an effort to integrate undergraduate research experience in the curriculum at Hampton University (HU), a Historically Black University, two successful cancer biology and epidemiology curricula were developed in collaboration with the University of Pittsburgh Cancer Institute (UPCI). These curricula included the development of a total of four research‐intense undergraduate courses in cancer biology and epidemiology: a cancer biology and bioinformatics lecture course; a cancer epidemiology lecture course; a cancer biotechnique laboratory course; and a cancer seminar/workshop course. These courses were open to any student who had at least one year of general biology. In addition, a subset of students were recruited not only to participate in these classes but to also spend one summer at either UPCI or the State University of New York ‐ Downstate School of Public Health engaging in cancer and/or epidemiology research. Students enrolled in these curricula gained knowledge in cancer biology, various forms of epidemiological study designs, data analyses, hypothesis generation, results interpretation, manuscript writing, and hands‐on experience in cancer research. This collaboration resulted so far in 22 poster presentations and 7 publications. Five of the 7 publications are co‐authored by students. About 90% of the students involved in the summer research matriculated in either graduate or professional school after graduation from HU. In conclusion, the inclusion of undergraduate research experience in our curricula has enhanced the ability of our students to matriculate in and graduate from graduate and professional schools.This work was supported in part by two National Cancer Institute P20 grants: 5P20CA101445 and 5P20CA132532.
Interplay of microRNAs and RNA binding proteins
Authors: Port J. David , Polk Jeremy 
Published: June 2021

We have demonstrated previously that β‐adrenergic receptor (AR) mRNAs are targets for RNA‐binding proteins (BPs) that bind to A+U‐rich elements (AREs) within their 3′untranslated regions (UTRs). Our hypothesis is that ARE‐BPs and miRNAs interact affecting each other's ability to modulate gene expression. Herein, we focus on miR let‐7 and the ARE‐BP, HuR.ResultsThe human β1‐AR 3′UTR was placed down‐stream of a dual luciferase reporter and cells were treated with miR mimics/inhibitors. Compared to control (1.00), let‐7 mimic down‐regulated LUC/β1‐AR expression (0.61 ± 0.04). Conversely, let‐7 inhibitor increased β1‐AR expression (1.80 ± 0.21). Mutagenesis of the let‐7 site, (−)let‐7, completely abrogated the effects of let‐7 mimic/inhibitor. HuR knockdown (~75%) also resulted in decreased LUC/β1‐AR expression (0.62 ± 0.03). In cells expressing LUC/β1‐AR(−)let‐7, β‐AR down‐regulation 2o to HuR knockdown was attenuated (0.85 ± 0.06). The effects of let‐7 mimic/inhibitor were also examined in cells expressing LUC/β1‐AR(−)ARE. Absence of the ARE completely abrogated the effects of both let‐7 mimic/inhibitor.ConclusionThe current data supports the conclusion that modulation of β‐AR expression by HuR is let‐7 dependent. Reciprocally, let‐7 function appears dependent on the presence of an ARE and on the proteins that bind to it.
Characterization of the interaction between Hsp70s and lipids: evolutionary and functional implications
Authors: Nikolaidis Nikolas , McCallister Chelsea , Donnelly Gabrielle , Le Dat 
Published: June 2021

Hsp70s are molecular chaperones indispensable for cellular homeostasis under both normal and pathological conditions. Apart from their associations with protein substrates, Hsp70s also associate with membrane lipids. This association has been related to their membrane localization and anchorage, secretion and endocytosis, as well as their functions in stabilizing membranes and cell signaling. Despite the essential role of membrane‐associated Hsp70s in cell survival, their interactions with membranes and lipids, as well as the effect that lipid‐binding has on their chaperone activities remain unknown. To this end, we determined that several eukaryotic and prokaryotic Hsp70s bind to phospholipids with different affinities suggesting that Hsp70s are functionally differentiated with respect to their lipid‐binding properties. We next established that the nucleotide binding domain of Hsp70s contains multiple lipid‐binding sites, a result that was also supported by mutagenesis experiments, which further identified critical residues for different lipids. Furthermore, we determined that lipid‐binding significantly reduces the refolding activity of Hsp70s, suggesting a new regulatory mechanism of chaperone function. Collectively, these results provide fundamental knowledge towards understanding the full spectrum of biologically significant activities mediated by Hsp70‐lipid interactions.This project was supported by funds from CSUPERB and CSUF to NN.
The structural basis for neuropilin‐ligand interactions
Authors: Parker Matthew W. , Li Xiaobo , Guo Hou-Fu , Xu Ping , Vander Kooi Craig W. 
Published: June 2021

Neuropilin is an essential cell surface receptor that functions in vascular endothelial growth factor (VEGF) dependent vascularization and semaphorin dependent axon guidance. We demonstrate that neuropilin ligands necessarily possess a C‐terminal arginine. We show that the presence of a C‐terminal arginine is critical for VEGF binding to neuropilin. This result has allowed us to explain the marked difference in the activity of different VEGF‐A splice forms. We further demonstrate that a C‐terminal arginine is critical for the binding of semaphorin to neuropilin, but that this is dependent on furin proteolysis. This modification is found to regulate not only semaphorin binding to neuropilin, but it directly modulates competitive binding between Sema3F and VEGF‐A for Nrp1. Having defined this necessary ligand feature, we are working to define additional molecular interactions that regulate ligand binding specificity. Our work also opens new avenues towards the development of selective neuropilin inhibitors.Supported by NIH Grants T32HL072743 and R01GM094155.
Mining Open Reading Frames (ORF) of the human secretome identifies a novel candidate ligand in Esophageal Cancer Related Gene‐4 (ECRG4)
Authors: Dang Xitong , Podvin Sonia , Larocca David , Muchinyi Stephen , Coimbra Raul , Eliceiri Brian , Baird Andrew 
Published: June 2021

ObjectiveThese studies aimed to use phage display to identify hidden ligands and ligand‐domains in orphan ORF of genes of the human secretome.MethodsLibraries containing 100–200 base pair fragments were generated by random fragmentation of either the 4.5 Kb human epidermal growth factor (EGF) or the 0.5Kb human ECRG4 ORF using DNase I. DNA fragments were then displayed on filamentous phage and the libraries were biopanned for phage capable of internalizing into PC3 epithelial cells. After PCR recovery of internalized phages, candidate ligands or ligand‐domains were sequenced and nucleotides that were in‐frame with both geneIII and the ORF were identified by comparative analyses.ResultsAfter one round biopanning, 8 colonies contained a core 53‐aminoacid human EGF ligand, in‐frame with pIII and all derived from the C‐terminus of the EGF pre‐pro‐precursor. When the method was applied to the hormone‐like precursor Ecrg4, a potential ligand, Ecrg4(37–62), was in‐frame to both geneIII and the ORF was identified. The authenticity of this ligand‐domain was confirmed by immunostaining intracellular phages in PC3 and HEK cells and by quantifying recovery using real time PCR of treated PC3 cells and normal human dermal fibroblasts.ConclusionThe data establish that phage display can be used for mining ORFs of the human secretome and that a ligand‐like domain in the Ecrg4 ORF that can target epithelial cells.
An Unconventional Rab GTPase is Involved in the Regulation of Unique Secretory Organelles in Toxoplasma gondii
Authors: Heng Joanne , Kremer Katrin , Meissner Markus 
Published: June 2021

The apicomplexan parasite, Toxoplasma gondii, has a highly polarised secretory system and relies on the sequential secretion of virulence factors from unique organelles (micronemes, rhoptries and dense granules) for parasite invasion and propagation. The timely delivery of proteins to these organelles involves correct protein sorting and transport and thus highly organised trafficking pathways. Rab GTPases (of which apicomplexan parasites have a reduced set) are small G‐proteins that act as molecular switches during the transport of a vesicle from a donor to an acceptor membrane. In T. gondii, the role of the conserved endocytic Rab5 proteins (Rab5A and C) has been modulated to traffick proteins to distinct micronemal subsets. Rab5B is alveolate‐specific and its role in protein trafficking in T. gondii has been investigated using an inducible protein expression system. Over‐expression of Rab5B has a severe effect on parasite growth as a result of disrupted host‐cell egress. The elucidation of Rab5B‐dependent protein trafficking has also highlighted a role in micronemal secretion and may thus indicate a role in signalling pathways important during the parasite lifecycle.Supported by Wellcome Trust.Grant Funding Source : Wellcome Trust.