bluuebunny/crossref_metadata_2025_split huggingface dataset:
Radiosynthesis,in vitroand preliminaryin vivoevaluation of the novel glutamine derived PET tracers [18F]fluorophenylglutamine and [18F]fluorobiphenylglutamine
Authors: Baguet Tristan , Verhoeven Jeroen , Pauwelyn Glenn , Hu Jiyun , Lambe Patricia , De Lombaerde Stef , Piron Sarah , Donche Sam , Descamps Benedicte , Goethals Ingeborg , Vanhove Christian , De Vos Filip , Beyzavi M. Hassan 
Published: February 2020

AbstractIntroductionGlucose has been deemed the driving force of tumor growth for decades. However, research has shown that several tumors metabolically shift towards glutaminolysis. The development of radiolabeled glutamine derivatives could be a useful molecular imaging tool for visualizing these tumors. We elaborated on the glutamine-derived PET tracers by developing two novel probes, namely [18F]fluorophenylglutamine and [18F]fluorobiphenylglutamineMaterials and methodsBoth tracers were labelled with fluorine-18 using our recently reported ruthenium-based direct aromatic fluorination method. Their affinity was evaluated with a [3H]glutamine inhibition experiment in a human PC-3 and a rat F98 cell line. The imaging potential of [18F]fluorophenylglutamine and [18F]fluorobiphenylglutamine was tested using a mouse PC-3 and a rat F98 tumor model.ResultsThe radiosynthesis of both tracers was successful with overall non-decay corrected yields of 18.46 ± 4.18 % (n=10) ([18F]fluorophenylglutamine) and 8.05 ± 3.25 % (n=5) ([18F]fluorobiphenylglutamine).In vitroinhibition experiments showed a moderate and low affinity of fluorophenylglutamine and fluorobiphenylglutamine, respectively, towards the human ASCT-2 transporter. Both compounds had a low affinity towards the rat ASCT-2 transporter. These results were endorsed by thein vivoexperiments with low uptake of both tracers in the F98 rat xenograft, low uptake of [18F]FBPG in the mice PC-3 xenograft and a moderate uptake of [18F]FPG in the PC-3 tumors.ConclusionWe investigated the imaging potential of two novel PET radiotracers [18F]FPG and [18F]FBPG. [18F]FPG is the first example of a glutamine radiotracer derivatized with a phenyl group which enables the exploration of further derivatization of the phenyl group to increase the affinity and imaging qualities. We hypothesize that increasing the affinity of [18F]FPG by optimizing the substituents of the arene ring can result in a high-quality glutamine-based PET radiotracer.Advances in Knowledge and Implications for patient careWe hereby report novel glutamine-based PET-tracers. These tracers are tagged on the arene group with fluorine-18, hereby preventingin vivodefluorination, which can occur with alkyl labelled tracers (e.g. (2S,4R)4-[18F]fluoroglutamine). [18F]FPG shows clear tumor uptakein vivo, has noin vivodefluorination and has a straightforward production. We believe this tracer is a good starting point for the development of a high-quality tracer which is useful for the clinical visualization of the glutamine transport.
Cell-cell communication through FGF4 generates and maintains robust proportions of differentiated cell types in embryonic stem cells
Authors: Raina Dhruv , Bahadori Azra , Stanoev Angel , Protzek Michelle , Koseska Aneta , Schröter Christian 
Published: February 2020

SummaryDuring embryonic development and tissue homeostasis, reproducible proportions of differentiated cell types are specified from populations of multipotent precursor cells. Molecular mechanisms that enable both robust cell type proportioning despite variable initial conditions in the precursor cells, as well as the re-establishment of these proportions upon perturbations in a developing tissue remain to be characterized. Here we report that the differentiation of robust proportions of epiblast-like and primitive endoderm-like cells in mouse embryonic stem cell cultures emerges at the population level through cell-cell communication via a short-range FGF4 signal. We characterize the molecular and dynamical properties of the communication mechanism, and show how it controls both robust cell type proportioning from a wide range of experimentally controlled initial conditions, as well as the autonomous re-establishment of these proportions following the isolation of one cell type. The generation and maintenance of reproducible proportions of discrete cell types is a new function for FGF signaling that may operate in a range of developing tissues.
Open microfluidic coculture reveals paracrine signaling from human kidney epithelial cells promotes kidney specificity of endothelial cells
Authors: Zhang Tianzi , Lih Daniel , Nagao Ryan J. , Xue Jun , Berthier Erwin , Himmelfarb Jonathan , Zheng Ying , Theberge Ashleigh B. 
Published: February 2020

AbstractEndothelial cells (ECs) from different human organs possess organ-specific characteristics that support specific tissue regeneration and organ development. EC specificity are identified by both intrinsic and extrinsic cues, among which, parenchyma and organ-specific microenvironment are critical contributors. These extrinsic cues are, however, largely lost duringex vivocultures. Outstanding challenges remain to understand and re-establish EC organ-specificity forin vitrostudies to recapitulate human organ-specific physiology. Here, we designed an open microfluidic platform to study the role of human kidney tubular epithelial cells in supporting EC specificity. The platform consists of two independent cell culture regions segregated with a half wall; culture media is added to connect the two culture regions at a desired timepoint, and signaling molecules can travel across the half wall (paracrine signaling). Specifically, we report that in the microscale coculture device, primary human kidney proximal tubular epithelial cells (HPTECs) rescued primary human kidney peritubular microvascular EC (HKMEC) monolayer integrity and fenestra formation, and HPTECs upregulated key HKMEC kidney-specific genes (HNF1B,AJAP1,KCNJ16) and endothelial activation genes (VCAM1,MMP7,MMP10) in coculture. Co-culturing with HPTECs also promoted kidney-specific genotype expression in human umbilical vein ECs (HUVECs), and human pluripotent stem cell-derived ECs (hPSC-ECs). In comparison to the culture in HPTEC conditioned media, co-culture of ECs with HPTECs showed increased upregulation of kidney specific genes, suggesting potential bidirectional paracrine signaling. Importantly, our device is compatible with standard pipettes, incubators, and imaging readouts, and could also be easily adapted to study cell signaling between other rare or sensitive cells.
Structural basis of substrate recognition and catalysis by fucosyltransferase 8
Authors: Järvå Michael A. , Dramicanin Marija , Lingford James P. , Mao Runyu , John Alan , Jarman Kate , Grinter Rhys W. , Goddard-Borger Ethan D. 
Published: February 2020

AbstractFucosylation of the inner-most N-acetyl-glucosamine (GlcNAc) of N-glycans by fucosyltransferase 8 (FUT8) is an important step in the maturation of complex and hybrid N-glycans. This simple modification can have a dramatic impact on the activity and half-life of glycoproteins. These effects are relevant to understanding the invasiveness of some cancers, the development of monoclonal antibody therapeutics, and to a congenital disorder of glycosylation. The acceptor substrate preferences of FUT8 are well characterised and provide a framework for understanding N-glycan maturation in the Golgi, however the structural basis for these substrate preferences and the mechanism through which catalysis is achieved remains unknown. Here, we describe several structures of mouse and human FUT8 in the apo state and in complex with guanosine diphosphate (GDP), a mimic of the donor substrate, and a glycopeptide acceptor substrate. These structures provide insights into: a unique conformational change associated with donor substrate binding; common strategies employed by fucosyltransferases to coordinate GDP; features that define acceptor substrate preferences; and a likely mechanism for enzyme catalysis. Together with molecular dynamics simulations, the structures also reveal how FUT8 dimerisation plays an important role in defining the acceptor substrate binding site. Collectively, this information significantly builds on our understanding of the core-fucosylation process.
Integrin Affinity Modulation Critically Regulates Atherogenic Endothelial Activationin vitroandin vivo
Authors: Al-Yafeai Zaki , Peretik Jonette M. , Pearson Brenna H. , Bhattarai Umesh , Wang Dongdong , Petrich Brian G. , Orr A. Wayne 
Published: February 2020

AbstractWhile vital to platelet and leukocyte adhesion, the role of integrin affinity modulation in adherent cells remains controversial. In endothelial cells, atheroprone hemodynamics and oxidized lipoproteins drive an increase in the high affinity conformation of α5β1 integrins in endothelial cellsin vitro, and α5β1 integrin inhibitors reduce proinflammatory endothelial activation to these stimuliin vitroandin vivo. However, the importance of α5β1 integrin affinity modulation to endothelial phenotype remains unknown. We now show that endothelial cells (talin1 L325R) unable to induce high affinity integrins initially adhere and spread, but show significant defects in nascent adhesion formation. In contrast, overall focal adhesion number, area, and composition in stably adherent cells are similar between talin1 wildtype and talin1 L325R endothelial cells. However, talin1 L325R endothelial cells fail to induce high affinity α5β1 integrins, fibronectin deposition, and proinflammatory responses to atheroprone hemodynamics and oxidized lipoproteins. Inducing the high affinity conformation of α5β1 integrins in talin1 L325R cells partially restores fibronectin deposition, whereas NF-κB activation and maximal fibronectin deposition require both integrin activation and other integrin-independent signaling. In endothelial-specific talin1 L325R mice, atheroprone hemodynamics fail to promote inflammation and macrophage recruitment, demonstrating a vital role for integrin activation in regulating endothelial phenotype.
Parvalbumin+and Npas1+Pallidal Neurons Have Distinct Circuit Topology and Function
Authors: Pamukcu Arin , Cui Qiaoling , Xenias Harry S. , Berceau Brianna L. , Augustine Elizabeth C. , Fan Isabel , Chalasani Saivasudha , Hantman Adam W. , Lerner Talia N. , Boca Simina M. , Chan C. Savio 
Published: February 2020

AbstractThe external globus pallidus (GPe) is a critical node within the basal ganglia circuit. Phasic changes in the activity of GPe neurons during movement and their alterations in Parkinson’s disease (PD) argue that the GPe is important in motor control. PV+neurons and Npas1+neurons are the two principal neuron classes in the GPe. The distinct electrophysiological properties and axonal projection patterns argue that these two neuron classes serve different roles in regulating motor output. However, the causal relationship between GPe neuron classes and movement remains to be established. Here, by using optogenetic approaches in mice (both males and females), we showed that PV+neurons and Npas1+neurons promoted and suppressed locomotion, respectively. Moreover, PV+neurons and Npas1+neurons are under different synaptic influences from the subthalamic nucleus (STN). Additionally, we found a selective weakening of STN inputs to PV+neurons in the chronic 6-hydroxydopamine lesion model of PD. This finding reinforces the idea that the reciprocally connected GPe-STN network plays a key role in disease symptomatology and thus provides the basis for future circuit-based therapies.Significance StatementThe external pallidum is a key, yet an understudied component of the basal ganglia. Neural activity in the pallidum goes awry in neurological diseases, such as Parkinson’s disease. While this strongly argues that the pallidum plays a critical role in motor control, it has been difficult to establish the causal relationship between pallidal activity and motor (dys)function. This was in part due to the cellular complexity of the pallidum. Here, we showed that the two principal neuron types in the pallidum have opposing roles in motor control. In addition, we described the differences in their synaptic influence. Importantly, our research provides new insights into the cellular and circuit mechanisms that explain the hypokinetic features of Parkinson’s disease.
Alterations in the intrinsic properties of striatal cholinergic interneurons after dopamine lesion and chronic L-DOPA
Authors: Choi Se Joon , Ma Thong C. , Ding Yunmin , Cheung Timothy , Joshi Neal , Sulzer David , Mosharov Eugene V. , Kang Un Jung 
Published: February 2020

SummaryChanges in striatal cholinergic interneuron (ChI) activity are thought to contribute to Parkinson’s disease pathophysiology and dyskinesia from chronic L-3,4-dihydroxyphenylalanine (L-DOPA) treatment, but the physiological basis of these changes are unknown. We find that dopamine lesion decreases the spontaneous firing rate of ChIs, whereas chronic treatment with L-DOPA of lesioned mice increases baseline ChI firing rates to levels beyond normal activity. The effect of dopamine loss on ChIs was due to decreased currents of both hyperpolarization-activated cyclic nucleotide-gated (HCN) and small conductance calcium-activated potassium (SK) channels. L-DOPA reinstatement of dopamine normalized HCN activity, but SK current remained depressed. Pharmacological blockade of HCN and SK activities mimicked changes in firing, confirming that these channels are responsible for the molecular adaptation of ChIs to dopamine loss and chronic L-DOPA treatment. These findings suggest that targeting ChIs with channel-specific modulators may provide therapeutic approaches for alleviating L-DOPA-induced dyskinesia in PD patients.
Quantitative Proteomics and Phosphoproteomics Supports a Role for Mut9-Like Kinases in Multiple Metabolic and Signaling Pathways inArabidopsis
Authors: Wilson Margaret E. , Tzeng Shin-Cheng , Augustin Megan M. , Meyer Matthew , Jiang Xiaoyue , Choi Jae H. , Rogers John C. , Evans Bradley S. , Kutchan Toni M. , Nusinow Dmitri A. 
Published: February 2020

Summary/AbstractProtein phosphorylation is one of the most prevalent post-translational modifications found in eukaryotic systems. It serves as a key molecular mechanism that regulates protein function in response to environmental stimuli. The Mut9-Like Kinases (MLKs) are a plant-specific family of Ser/Thr kinases linked to light, circadian, and abiotic stress signaling. Here we use quantitative phosphoproteomics in conjunction with global proteomic analysis to explore the role of the MLKs in daily protein dynamics. Proteins involved in light, circadian, and hormone signaling, as well as several chromatin-modifying enzymes and DNA damage response factors, were found to have altered phosphorylation profiles in the absence of MLK family kinases. In addition to altered phosphorylation levels,mlkmutant seedlings have an increase in glucosinolate metabolism enzymes. Subsequently, we show that a functional consequence of the changes to the proteome and phosphoproteome inmlkmutant plants is elevated glucosinolate accumulation, and increased sensitivity to DNA damaging agents. Combined with previous reports, this work supports the involvement of MLKs in a diverse set of stress responses and developmental processes, suggesting that the MLKs serve as key regulators linking environmental inputs to developmental outputs.
PDH Mediated Mitochondrial Respiration Controls the Speed of Muscle Stem Cell Activation in Muscle Repair and Aging
Authors: Raval Manmeet H. , Cheng Pin-Chung , Guardino Nicholas , Ahsan Sanjana , Zhou Hao , Tiwari Rajiv Lochan , Wang Lu , Chareunsouk Andrew , Ederer Maxwell , Hwang Ara B. , Ellenberger Matt , Pepin Rob , Raftery Daniel , Promislow Daniel , Shen Keyue , Brack Andrew S. , Rodgers Joseph T. 
Published: February 2020

ABSTRACTDecline in the skeletal muscle stem cell (MuSC) function is a major contributor to age-associated impairments in muscle regeneration and function. The ability of MuSCs to activate (i.e. exit quiescence, enter the cell cycle, and divide) following injury is a critical step that initiates muscle regeneration. However, the mechanisms that regulate MuSC activation function are poorly understood. Here, we show that the activation function, specifically the speed by which cells progress through G0-G1, declines tremendously with age in mouse MuSCs. Using a number ofin vivomodels andex vivoassays of MuSC activation and muscle regenerative functions, live cell metabolic flux analyses, and metabolomics we present data indicating that changes in MuSC mitochondrial flux underlie age-associated changes in MuSC activation. We show that, in the course of MuSC activation, there is a profound,16-fold, increase in ATP production rates, which is fueled largely by increases in pyruvate flux into mitochondria. We found that MuSCs from aged mice display progressive defects in the ability to increase mitochondrial flux during activation and that this correlates with higher levels of phosphorylated, inactivated, pyruvate dehydrogenase (PDH). Importantly, we demonstrate that pharmacologic and physiologic methods to induce dephosphorylation and activation of PDH in MuSCs are sufficient to rescue the activation and muscle regenerative functions of MuSCs in aged mice. Collectively the data presented show that MuSC mitochondrial function is a central regulator of MuSC activation and muscle regenerative functions. Moreover, our results suggest that approaches to increase MuSC pyruvate oxidation may have therapeutic potential to promote muscle repair and regeneration.
RNAAgeCalc: A multi-tissue transcriptional age calculator
Authors: Ren Xu , Kuan Pei Fen 
Published: February 2020

SUMMARYWe introduced RNAAgeCalc, a versatile across-tissue and tissue-specific transcriptional age calculator. We utilized GTEx database to identify 1,616 common age-related genes based on meta-analysis of transcriptional age signature across multi-tissues. Additionally, tissue-specific age-related genes were obtained from differential expression analysis on individual tissues. By performing across-tissue transcriptional age prediction, we showed that our 1,616 common age-related genes outperformed other prior age related gene signatures. Furthermore, we utilized TCGA database to demonstrate that the transcriptional age acceleration computed from our within-tissue predictor was significantly correlated with mutation burden, mortality risk and cancer stage. RNAAgeCalc is available athttp://www.ams.sunysb.edu/~pfkuan/softwares.html#RNAAgeCalc.
WDR90 is a centriolar microtubule wall protein important for centriole architecture integrity
Authors: Steib Emmanuelle , Gambarotto Davide , Laporte Marine , Olieric Natacha , Zheng Céline , Borgers Susanne , Olieric Vincent , Le Guennec Maeva , Koll France , Tassin Anne-Marie , Steinmetz Michel O. , Guichard Paul , Hamel Virginie 
Published: February 2020

SummaryCentrioles are characterized by a nine-fold arrangement of long-lived microtubule triplets that are held together by an inner protein scaffold. These structurally robust organelles experience strenuous cellular processes such as cell division or ciliary beating while performing their function. However, the molecular mechanisms underlying the stability of microtubule triplets, as well as centriole architectural integrity remain poorly understood. Here, using ultrastructure expansion microscopy (U-ExM) for nanoscale protein mapping, we reveal that POC16 and its human homolog WDR90 are components of the centriolar microtubule wall along the central core region of the centriole. We further found that WDR90 is an evolutionary microtubule associated protein with a predicted structurally homology with the ciliary inner junction protein FAP20. Finally, we demonstrate that WDR90 depletion impairs the localization of inner scaffold components, leading to centriole structural abnormalities in both human andChlamydomonascells. Altogether, this work highlights that POC16/WDR90 is a crucial evolutionary conserved molecular player participating in centriole architecture integrity.
2 MV/cm Pulsed Electric Fields Promote Transthyretin Amyloid Disintegration
Authors: Urabe Gen , Sato Takashi , Nakamura Gomaru , Kobashigawa Yoshihiro , Morioka Hiroshi , Katsuki Sunao 
Published: February 2020

AbstractExposing transthyretin amyloid to 1000 sub-nanosecond 2 MV/cm pulsed electric fields (PEFs) promotes both amyloid disassembly and amyloid-derived transthyretin disintegration. The process produced no change in pH, and the resulting temperature increase was less than 1 °C. We conclude that PEFs’ physical effects facilitate amyloid disassembly, rather than thermal or chemical effects, and provoke amyloid-derived transthyretin disintegration, the latter of which is reported here for the first time.
Path integration changes as a cognitive marker for vascular cognitive impairment? – a pilot study
Authors: Lowry Ellen , Puthusseryppady Vaisakh , Coughlan Gillian , Jeffs Stephen , Hornberger Michael 
Published: February 2020

ABSTRACTPath integration spatial navigation processes are emerging as promising cognitive markers for prodromal and clinical Alzheimer’s disease (AD). However, such path integration changes have been little explored in Vascular Cognitive Impairment (VCI), despite neurovascular change being a major contributing factor to dementia and potentially AD. In particular, the sensitivity and specificity of path integration impairments in VCI compared to AD is unclear. In the current pilot study, we explore path integration performance in AD and VCI patient groups and hypothesise that i) medial parietal mediated egocentric processes will be more affected in VCI and ii) medial temporal mediated allocentric processes will be more affected in AD. This retrospective cross-sectional study included early stage VCI patients (n=9), AD patients (n=10) and healthy age-matched controls (n=20). All participants underwent extensive neuropsychological testing, as well as spatial navigation testing. The spatial navigation tests included the virtual reality ‘Supermarket’ task assessing egocentric (body-based) and allocentric (map-based) navigation as well as the ‘Clock Orientation’ test assessing egocentric and path integration processes. Results showed that egocentric path integration processes are only impaired in VCI, potentially distinguishing it from AD. However, in contrast to our prediction, allocentric path integration was similarly impaired for VCI and AD. These preliminary findings suggest limited specificity of allocentric path integration deficits between VCI and AD. By contrast, egocentric path integration deficits emerge as more specific to VCI, potentially allowing for more specific diagnostic and treatment outcome measures for vascular impairment in dementia.