bluuebunny/crossref_metadata_2025 huggingface dataset:
Circadian Oscillations Persist in Low Malignancy Breast Cancer Cells
Authors: Lellupitiyage Don Sujeewa S. , Lin Hui-Hsien , Furtado Jessica J. , Qraitem Maan , Taylor Stephanie R. , Farkas Michelle E.
Published: June 2019

Epidemiological studies have shown that humans with altered circadian rhythms have higher cancer incidence, with breast cancer being one of the most cited examples. To uncover how circadian disruptions may be correlated with breast cancer and its development, prior studies have assessed the expression of BMAL1 and PER2 core clock genes via RT-qPCR and western blot analyses. These and our own low-resolution data show that BMAL1 and PER2 expression are suppressed and arrhythmic. We hypothesized that oscillations persist in breast cancer cells, but due to limitations of protocols utilized, cannot be observed. This is especially true where dynamic changes may be subtle. In the present work, we generated luciferase reporter cell lines representing high- and low-grade breast cancers to assess circadian rhythms. We tracked signals for BMAL1 and PER2 to determine whether and to what extent oscillations exist and provide initial correlations of circadian rhythm alterations with breast cancer aggression. In contrast to previous studies, where the clock was deemed to be “broken” in breast cancer, our luminometry data reveal that circadian oscillations of BMAL1 and PER2 do in fact exist in the low-grade, luminal A cell line, MCF7 but are not apparent in high-grade, basal MDA-MB-231 cells. To our knowledge, this is the first evidence of core circadian clock oscillations in breast cancer cells. This work also suggests that circadian rhythms are increasingly disrupted with breast cancer tumor grade/aggressiveness, and that use of real time luminometry to study additional representatives of breast and other cancer subtypes is highly merited.
Phosphatidylcholine biosynthesis in Mitis group streptococci via host metabolite scavenging
Authors: Joyce Luke R. , Guan Ziqiang , Palmer Kelli L.
Published: June 2019

The Mitis group streptococci include the major human pathogenStreptococcus pneumoniaeand the opportunistic pathogensS. mitisandS. oraliswhich are human oral cavity colonizers and agents of bacteremia and infective endocarditis in immunocompromised patients. Bacterial membrane lipids play crucial roles in microbe-host interactions, yet for many pathogens, the composition of the membrane is poorly understood. In this study, we characterized the lipidomes of selected species of Mitis group streptococci and investigated the mechanistic basis for biosynthesis of the phospholipid phosphatidylcholine (PC). PC is a major lipid in eukaryotic cellular membranes, but it is considered to be comparatively rare in bacterial taxa. Using liquid chromatography/mass spectrometry (LC/MS) in conjunction with stable isotope tracing, we determined that Mitis group streptococci synthesize PC via the rare host metabolite scavenging pathway, the glycerophosphocholine (GPC) pathway, which is largely uncharacterized in bacteria. Our work demonstrates that Mitis group streptococci includingS. pneumoniaeremodel their membrane in response to the major human metabolites GPC and lysoPC.

Importance

We lack fundamental information about the composition of the cellular membrane even for the best studied pathogens of critical significance for human health. The Mitis group streptococci are closely linked to humans in health and disease, yet their membrane biology is poorly understood. Here, we demonstrate that these streptococci scavenge major human metabolites and use them to synthesize the membrane phospholipid phosphatidylcholine. Our work is significant because it identifies a mechanism by which the major human pathogenS. pneumoniaeand the primary human oral colonizersS. mitisandS. oralisremodel their membrane in response to host metabolites.
Correction of β3 integrin haplo-insufficiency by CRISPRa normalizes cortical network activity
Authors: Jaudon Fanny , Thalhammer Agnes , Cingolani Lorenzo A.
Published: June 2019

The extracellular matrix (ECM) plays an essential role in regulating the function of neuronal networks. In many cell types, the ECM exerts its effects through the transmembrane receptors integrins. Here, we investigate whether neuronal integrins regulate network excitability. Specifically, we focus on β3 integrin, which has been associated to autism spectrum disorder and whose expression in neurons is regulated by activity. We have designed CRISPRa tools to titrate β3 integrin expression in neurons. By using multi-electrode arrays and Ca2+imaging, we show that β3 integrin boosts network excitability and synchrony in primary cortical neurons. Crucially, CRISPRa could compensate precisely for β3 integrin haplo-insufficiency, thereby rebalancing level and correlation of neuronal activity. By contrast, rescue strategies based on exogenous gene expression resulted in hyper-active networks firing in unison. Thus, regulation of β3 integrin by CRISPRa provides a precise and efficient system for modulating neuronal network function.
Heavy Chain CDR 3 and Junctional Length Biases in Human Antibody Repertoires Associated with Heavy and Light Chain Germline Utilization
Authors: Sankar Kannan , Hoi Kam Hon , Hötzel Isidro
Published: June 2019

Antibody variable domain sequence diversity is generated by recombination of germline segments. The third complementarity-determining region of the heavy chain (CDR H3) is the region of highest sequence diversity and is formed by the joining of heavy chain VH, DH and JH germline segments combined with random nucleotide trimming and additions between these segments. We show that CDR H3 length distribution is biased in human antibody repertoires as a function of VH, VL and JH germline segment utilization. Most length biases are apparent in the naïve B cell compartment, with a significant bias towards shorter CDR H3 sequences observed in association with a subset of VH and VL germlines in the antigen experienced compartment. Similar biases were not observed in nonproductive heavy chain recombination products, indicating selection of the repertoire during B cell maturation as a major driver of the length biases. Some VH-associated CDR H3 length biases are dependent on utilization of specific JH germline segments in a manner not directly linked to JH segment length in the germline, but are rather associated with selection of differentially trimmed JH segments in the naïve compartment. In addition, DH segment and N-region random nucleotide insertion lengths within CDR H3 in the naïve compartment were also biased by specific VH/JH germline combinations, indicating a complex set of constraints between germline segments selected during repertoire maturation. Our findings reveal biases in the antibody diversity landscape shaped by VH, VL, and JH germline features with implications for mechanisms of naïve and immune repertoire selection.
The observation of explicit and implicit visuomotor cues can drive predictive motor control
Authors: Rens Guy , Davare Marco
Published: June 2019

Recent studies have highlighted that the observation of hand-object interactions can influence perceptual weight judgements made by an observer. Moreover, observing explicit motor errors during object lifting allows individuals to update their internal sensorimotor representation about object weight. Embodying observed visuomotor cues for the planning of a motor command further enables individuals to accurately scale their fingertip forces when subsequently lifting the same object. However, it is still unknown whether observation of a skilled lift is equally able to mediate predictive motor control in the observer. Here, we tested this hypothesis by asking participants to grasp and lift a manipulandum after observing an actor’s lift. The object weight changed unpredictably (light or heavy) every third to sixth trial performed by the actor. Participants were informed that they would always lift the same weight as the actor and that, based on the experimental condition, they would have to observe skilled or erroneously performed lifts. Our results revealed that the observation of both skilled and erroneously performed lifts allows participants to update their internal sensorimotor object representation, in turn enabling them to predict force scaling accurately. These findings suggest that the observation of explicit as well as implicit visuomotor cues are embodied in the observer’s motor repertoire and can drive changes in predictive motor control.
The dynamic chromatin architecture of the regenerating liver
Authors: Wang Amber W. , Wang Yue J. , Zahm Adam M. , Morgan Ashleigh R. , Wangensteen Kirk J. , Kaestner Klaus H.
Published: June 2019

Background & Aims

The adult liver is the main detoxification organ and is routinely exposed to environmental insults but retains the ability to restore its mass and function upon tissue damage. However, massive injury can lead to liver failure, and chronic injury causes fibrosis, cirrhosis, and hepatocellular carcinoma. Currently, the transcriptional regulation of organ repair in the adult liver is incompletely understood.

Methods

We isolated nuclei from quiescent as well as repopulating hepatocytes in a mouse model of hereditary tyrosinemia, which recapitulates the injury and repopulation seen in toxic liver injury in humans. We then performed the ‘assay for transposase accessible chromatin with high-throughput sequencing’ (ATAC-seq) specifically in repopulating hepatocytes to identify differentially accessible chromatin regions and nucleosome positioning. Additionally, we employed motif analysis to predict differential transcription factor occupancy and validated the in silico results with chromatin immunoprecipitation followed by sequencing (ChIP-seq) for hepatocyte nuclear factor 4α (HNF4α) and CCCTC-binding factor (CTCF).

Results

Chromatin accessibility in repopulating hepatocytes was increased in the regulatory regions of genes promoting proliferation and decreased in the regulatory regions of genes involved in metabolism. The epigenetic changes at promoters and liver enhancers correspond with regulation of gene expression, with enhancers of many liver function genes displaying a less accessible state during the regenerative process. Moreover, increased CTCF occupancy at promoters and decreased HNF4α binding at enhancers implicate these factors as key drivers of the transcriptomic changes in replicating hepatocytes that enable liver repopulation.

Conclusions

Our analysis of hepatocyte-specific epigenomic changes during liver repopulation identified CTCF and HNF4α as key regulators of hepatocyte proliferation and regulation of metabolic programs. Thus, liver repopulation in the setting of toxic injury makes use of both general transcription factors (CTCF) for promoter activation, and reduced binding by a hepatocyte-enriched factor (HNF4α) to temporarily limit enhancer activity.

Graphical Abstract
Inspiratory rhythmogenic activity is burst-independent and opioid-sensitive
Authors: Sun Xiaolu , Thörn Pérez Carolina , Nagaraj Halemani D , Shao Xuesi M. , Greenwood Morgan , Heath Sarah , Feldman Jack L. , Kam Kaiwen
Published: June 2019

How mammalian neural circuits generate rhythmic activity in motor behaviors, such as breathing, walking, and chewing, remains elusive. For breathing, rhythm generation can be localized to a brainstem nucleus called the preBötzinger Complex (preBötC). Rhythmic preBötC population activity consists of small amplitude burstlets, which we hypothesize are rhythmogenic, and larger inspiratory bursts, which drive motoneuronal activity. If burstlets are rhythmogenic, opioids, analgesics that can cause profound respiratory depression, should similarly reduce burstlet frequency. In conditions where burstlets were separated from bursts in medullary slices from neonatal mice, the μ-opioid receptor (μOR) agonist DAMGO decreased burstlet frequency. DAMGO-mediated depression was abolished by genetic deletion of μORs in a glutamatergic preBötC subpopulation and was reduced by Substance P, but not blockade of inhibitory synaptic transmission. Our findings suggest that rhythmogenesis need not rely on strong bursts of activity associated with motor output and point to strategies for ameliorating opioid-induced depression of breathing.
Pervasive Translation in Mycobacterium tuberculosis
Authors: Smith Carol , Canestrari Jill G. , Wang Archer J. , Champion Matthew M. , Derbyshire Keith M. , Gray Todd A. , Wade Joseph T.
Published: June 2019

Most bacterial ORFs are identified by automated prediction algorithms. However, these algorithms often fail to identify ORFs lacking canonical features such as a length of >50 codons or the presence of an upstream Shine-Dalgarno sequence. Here, we use ribosome profiling approaches to identify actively translated ORFs in Mycobacterium tuberculosis. Most of the ORFs we identify have not been previously described, indicating that the M. tuberculosis transcriptome is pervasively translated. The newly described ORFs are predominantly short, with many encoding proteins of ≤50 amino acids. Codon usage of the newly discovered ORFs suggests that most have not been subject to purifying selection, and hence do not contribute to cell fitness. Nevertheless, we identify 90 new ORFs (median length of 52 codons) that bear the hallmarks of purifying selection. Thus, our data suggest that pervasive translation of short ORFs in Mycobacterium tuberculosis serves as a rich source for the evolution of new functional proteins.
A systems chemoproteomic analysis of acyl-CoA/protein interaction networks
Authors: Levy Michaella J. , Montgomery David C. , Sardiu Mihaela E. , Bergholtz Sarah E. , Nance Kellie D. , Montano Jose , Thorpe Abigail L. , Fox Stephen D. , Lin Qishan , Andresson Thorkell , Florens Laurence , Washburn Michael P. , Meier Jordan L.
Published: June 2019

Acyl-CoA/protein interactions are required for many functions essential to life including membrane synthesis, oxidative metabolism, and macromolecular acetylation. However, despite their importance, the global scope and selectivity of these protein-metabolite interactions remains undefined. Here we describe the development of CATNIP (CoA/AcetylTraNsferase Interaction Profiling), a chemoproteomic platform for the high-throughput analysis of acyl-CoA/protein interactions in endogenous proteomes. First, we apply CATNIP to identify acetyl-CoA-binding proteins through unbiased clustering of competitive dose-response data. Next, we use this method to profile diverse protein-CoA metabolite interactions, identifying biological processes susceptible to altered acetyl-CoA levels. Finally, we apply systems-level analyses to assess the features of novel protein networks that may interact with acyl-CoAs, and demonstrate a strategy for high-confidence proteomic annotation of acetyl-CoA binding proteins. Overall our studies illustrate the power of integrating chemoproteomics and systems biology, and provide a resource for understanding the roles of acyl-CoA metabolites in biology and disease.
Precise implantation of super-paramagnetic iron oxide (SPIO) nanoparticles in hippocampus with external rotating magnetic field (RMF) produces rapid antidepressent effects in mice
Authors: Chi Yao , Wenwen Cai , Mengqin Xia , Jingyi Dai ,   JF Sun Sr.
Published: June 2019

Background

TMS is an effective anti-depression method commonly used in clinical practice, but it also faces the problems of low spatial resolution, treatment parameters to be optimized and limitation in mechanism research.

Objective

To develop a precise magnetic stimulation anti-depression method for the scientific research of magnetic stimulation, especially the mechanism research in animal experiments.

Methods

The cytotoxicity test was conducted in advance to ensure the security of intervention from SPIO nanoparticles and RMF. In animal experiments, 300nl SPIO solution was injected into the right hippocampus of the CUMS model mice, and then treated experimental group mice with rotating magnetic field for five days. The Sucrose Preference Test (SPT), the Forced Swim Test (FST) and BDNF expression levels were used to evaluate the antidepressant effect of this method.

Results

No significant decrease of cell viability was observed when the iron concentration is between 52.2µg/ml and 208.8µg/ml. And the application of RMF with a certain frequency was considered to be safe in the cytotoxicity test. When treated with SPIO+RMF, the sucrose preference of SPIO+RMF group mice increased markedly (n=9, p<0.01 vs. CUMS), the FST immobile time reduced (n=8, P<0.05 vs. CUMS) and the BDNF level in the hippocampus was significantly up-regulated (n=5, P<0.01 vs. CUMS). However, merely SPIO intervention failed to be effective.

Conclusions

when intervened with external rotating magnetic field, the SPIO nanoparticles injected into the right hippocampus could produce rapid antidepressent effects in mice.
Class A PBPs have a distinct and unique role in the construction of the pneumococcal cell wall
Authors: Straume Daniel , Wiaroslawa Piechowiak Katarzyna , Olsen Silje , Stamsås Gro Anita , Berg Kari Helene , Kjos Morten , Heggenhougen Maria Victoria , Alcorlo Martin , Hermoso Juan A. , Håvarstein Leiv Sigve
Published: June 2019

In oval shapedStreptococcus pneumoniae, septal and longitudinal peptidoglycan synthesis is performed by independent functional complexes; the divisome and the elongasome. Penicillin binding proteins (PBPs) were long considered as the key peptidoglycan synthesizing enzymes in these complexes. Among these were the bifunctional class A PBPs, which are both glycosyltransferases and transpeptidases, and monofunctional class B PBPs with only transpeptidase activity. Recently, however, it was established that the monofunctional class B PBPs work together with non-PBP glycosyltransferases (FtsW and RodA) to make up the core peptidoglycan synthesizing machineries within the pneumococcal divisome (FtsW/PBP2x) and elongasome (RodA/PBP2b). The function of class A PBPs is therefore now an open question. Here we utilize the peptidoglycan hydrolase CbpD to show that class A PBPs have an autonomous role during cell wall synthesis inS. pneumoniae. Purified CbpD was shown to target the septum ofS. pneumoniaecells. Using assays to specifically inhibit PBP2x, we demonstrate that CbpD specifically target nascent peptidoglycan synthesized by the divisome. Notably, class A PBPs could process this nascent peptidoglycan from a CbpD-sensitive to a CbpD-resistant form. The class A PBP mediated processing was independent of divisome and elongasome activities. Class A PBPs thus constitute an autonomous functional entity which processes or repairs nascent peptidoglycan synthesized by FtsW/PBP2x. Our results support a model in which pneumococcal peptidoglycan is made by three functional entities, the divisome, the elongasome and a peptidoglycan-repairing or -remodelling complex consisting of bifunctional PBPs. To our knowledge this is the first time a specific function has been identified for class A PBPs in bacterial cell wall synthesis.
Microtubule-dependent transport of arenavirus matrix protein demonstrated using live-cell imaging microscopy
Authors: Takamatsu Yuki , Kajikawa Junichi , Muramoto Yukiko , Nakano Masahiro , Noda Takeshi
Published: June 2019

Lassa virus (LASV), belonging to the family Arenaviridae, causes severe haemorrhagic manifestations and is associated with a high mortality rate in humans. Thus, it is classified as a biosafety level (BSL)-4 agent. Since counter measures for LASV diseases are yet to be developed, it is important to elucidate the molecular mechanisms underlying the life cycle of the virus, including its viral and host cellular protein interactions. These underlying molecular mechanisms may serve as the key for developing novel therapeutic options. Lymphocytic choriomeningitis virus (LCMV), a close relative of LASV, is usually asymptomatic and is categorised as a BSL-2 agent. In the present study, we visualised the transport of viral matrix Z protein in LCMV-infected cells using live-cell imaging microscopy. We demonstrated that the transport of Z protein is mediated by polymerised microtubules. Interestingly, the transport of LASV Z protein showed characteristics similar to those of Z protein in LCMV-infected cells. The live-cell imaging system using LCMV provides an attractive surrogate measure for studying arenavirus matrix protein transport in BSL-2 laboratories. In addition, it could be also utilised to analyse the interactions between viral matrix proteins and the cellular cytoskeleton, as well as to evaluate the antiviral compounds that target the transport of viral matrix proteins.
Optogenetic control of Wnt signaling for modeling early embryogenic patterning with human pluripotent stem cells
Authors: Repina Nicole A. , Bao Xiaoping , Zimmermann Joshua A. , Joy David A. , Kane Ravi S. , Schaffer David V.
Published: June 2019

The processes of cell proliferation, differentiation, migration, and self-organization during early embryonic development are governed by dynamic, spatially and temporally varying morphogen signals. Analogous tissue patterns emerge spontaneously in embryonic stem cell (ESC) models for gastrulation, but mechanistic insight into this self-organization is limited by a lack of molecular methods to precisely control morphogen signal dynamics. Here we combine optogenetic stimulation and single-cell imaging approaches to study self-organization of human pluripotent stem cells. Precise control of morphogen signal dynamics, achieved through activation of canonical Wnt/β-catenin signaling over a broad high dynamic range (>500-fold) using an optoWnt optogenetic system, drove broad transcriptional changes and mesendoderm differentiation of human ESCs at high efficiency (>95% cells). Furthermore, activating Wnt signaling in subpopulations of ESCs in 2D and 3D cultures induced cell self-organization and morphogenesis reminiscent of human gastrulation, including changes in cell migration and epithelial to mesenchymal transition. Our findings thus reveal an instructive role for Wnt in directing cell patterning in this ESC model for gastrulation.
CYLD, a Mechanosensitive Deubiquitinase, Regulates TGFβ Signaling in Load-Induced Bone Formation
Authors: Nguyen Jacqueline , Massoumi Ramin , Alliston Tamara
Published: June 2019

Many signaling pathways involved in bone homeostasis also participate in the anabolic response of bone to mechanical loading. For example, TGFβ signaling coordinates the maintenance of bone mass and bone quality through its effects on osteoblasts, osteoclasts, and osteocytes. TGFβ signaling is also essential for the mechanosensitive formation of new bone. However, the mechanosensitive mechanisms controlling TGFβ signaling in osteocytes remain to be determined, particularly those that integrate TGFβ signaling with other early responses to mechanical stimulation. Here, we used an in vivo mouse hindlimb loading model to identify mechanosensitive molecules in the TGFβ pathway, and MLOY4 cells to evaluate their interactions with the prostaglandin E2 (PGE2) pathway, which is well-known for its rapid response to mechanical stimulation and its role in bone anabolism. Although mRNA levels for several TGFβ ligands, receptors, and effectors were unchanged, the level of phosphorylated Smad3 (pSmad3) was reduced in tibial bone as early as 3 hrs after early mechanical stimulation. We found that PGE2 and its receptor, EP2, repress pSmad3 levels and transactivation of Serpine1 in osteocytes. PGE2 and EP2 control the level of pSmad3 through a proteasome-dependent mechanism that relies on the deubiquitinase CYLD. CYLD protein levels were also reduced in the tibiae within 3 hrs of mechanical loading. Using CYLD-deficient mice, we found that CYLD is required for the rapid load-mediated repression of pSmad3 and for load-induced bone formation. These data introduce CYLD as a mechanosensitive deubiquitinase that participates in the PGE2-dependent repression of TGFβ signaling in osteocytes.
Preserved global cerebral blood flow accounts for youthful processing speed in older adults
Authors: Yang Fan Nils , Xie Long , Galli Olga , Detre John A. , Wolk David A. , Rao Hengyi
Published: June 2019

Preserved cognitive performance is one of the key contributors to successful aging. The processing speed theory and prefrontal executive theory – are competing theories regarding the general causes of cognitive aging. Here, we used a theoretically-driven framework to investigate the neural correlates of older adults with preserved processing speed. Older adults with youth-like processing speed (SuperAgers) were compared with normal aged adults (TypicalAgers) using neuroimaging methods. Global cerebral blood flow (CBF) accounted for approximately 45% of the variance in processing speed, while neither regional CBF nor other structural measures predicted additional variance. In addition, despite having significantly cortical thinning, SuperAgers still shown comparable global CBF levels with young adults. These results support the global mechanism suggested by processing speed theory and indicate that global CBF may serve as a biomarker of cognitive aging.
An integrated landscape of protein expression in human cancer
Authors: Jarnuczak Andrew F. , Najgebauer Hanna , Barzine Mitra , Kundu Deepti J. , Ghavidel Fatemeh , Perez-Riverol Yasset , Papatheodorou Irene , Brazma Alvis , Vizcaíno Juan Antonio
Published: June 2019

Using public proteomics datasets, mostly available through the PRIDE database, we assembled a proteomics resource for 191 cancer cell lines and 246 clinical tumour samples, across 13 cancer lineages. We found that baseline protein abundance in cell lines was generally representative of tumours. However, when considering differences in protein expression between tumour subtypes, as exemplified in the breast lineage, many of these changes were no longer recapitulated in the cell line models. Integration of proteomics and transcriptomics data suggested that the level of transcriptional control in cell lines changed significantly depending on their lineage. Additionally, in agreement with previous studies, variation in mRNA levels was often a poor predictor of changes in protein abundance. To our knowledge, this work constitutes the first meta-analysis study including cancer-related proteomics datasets. We anticipate this aggregated dataset will be of significant aid to future studies requiring a reference to baseline protein expression in cancer.
The rapid divergence of the Antarctic crinoid speciesPromachocrinus kerguelensis
Authors: Chehida Yacine Ben , Eléaume Marc , Gallut Cyril , Achaz Guillaume
Published: June 2019

Climatic oscillations in Antarctica caused a succession of expansion and reduction of the ice sheets covering the continental shelf of the Southern Ocean. For marine invertebrates, these successions are suspected to have driven allopatric speciation, endemism and the prevalence of cryptic species, leading to the so-called Antarctic ‘biodiversity pump’ hypothesis. Here we took advantage of the recent sampling effort influenced by the International Polar Year (2007-8) to test for the validity of this hypothesis for 1,797 samples of two recognized crinoid species:Promachocrinus kerguelensisandFlorometra mawsoni. Species delimitation analysis identified seven phylogroups. As previously suggested,Promachocrinus kerguelensisforms a complex of six cryptic species. Conversely, despite the morphological differences, our results show thatFlorometra mawsoniis a lineage nested withinPromachocrinus kerguelensis. It suggests thatFlorometra mawsoniandPromachocrinus kerguelensisbelong to the same complex of species. Furthermore, this study indicates that over time and space the different sectors of the Southern Ocean show a remarkable rapid turn-over in term of phylogroups composition and also of genetic variants within phylogroups. We argue that strong “apparent” genetic drift causes this rapid genetic turn-over. Finally, we dated the last common ancestor of all phylogroups at less than 1,000 years, raising doubts on the relevance of the Antarctic “biodiversity pump” for this complex of species. This work is a first step towards a better understanding of how life is diversifying in the Southern Ocean.
Respiratory viral infection alters the gut microbiota by inducing inappetence
Authors: Groves Helen T. , Higham Sophie L. , Moffatt Miriam F. , Cox Michael J. , Tregoning John S.
Published: June 2019

The gut microbiota has an important role in health and disease. Respiratory viral infections are extremely common but their impact on the composition and function of the gut microbiota is poorly understood. We previously observed a significant change in the gut microbiota after viral lung infection. Here we show that weight loss during Respiratory Syncytial Virus (RSV) or influenza virus infection was due to decreased food consumption, and that fasting mice independently of infection altered gut microbiota composition. While the acute phase TNF-α response drove early weight loss and inappetence during RSV infection, this was not sufficient to induce changes in the gut microbiota. However, depleting CD8+ cells increased food intake and prevented weight loss resulting in a reversal of the gut microbiota changes normally observed during RSV infection. Viral infection also led to changes in the faecal gut metabolome during RSV infection, with a significant shift in lipid metabolism. Sphingolipids, poly-unsaturated fatty acids (PUFAs) and the short-chain fatty acid (SCFA) valerate all increased in abundance in the faecal metabolome following RSV infection. Whether this, and the impact of infection-induced anorexia on the gut microbiota, are part of a protective, anti-inflammatory response during respiratory viral infections remains to be determined.
Caveolae coupling of melanocytes signaling and mechanics is required for human skin pigmentation
Authors: Domingues Lia , Hurbain Ilse , Gilles-Marsens Floriane , André Nathalie , Dewulf Melissa , Romao Maryse , de Lesegno Christine Viaris , Blouin Cédric , Guéré Christelle , Vié Katell , Raposo Graça , Lamaze Christophe , Delevoye Cédric
Published: June 2019

Tissue homeostasis requires regulation of cell-cell communication, which relies on signaling molecules and cell contacts. In skin epidermis, keratinocytes secrete specific factors transduced by melanocytes into signaling cues to promote their pigmentation and dendrite outgrowth, while melanocytes transfer melanin pigments to keratinocytes to convey skin photoprotection. How epidermal cells integrate these functions remains poorly characterized. Here, we found that caveolae polarize in melanocytes and are particularly abundant at melanocyte-keratinocyte interface. Caveolae in melanocytes are sensitive to ultra-violet radiations and miRNAs released by keratinocytes. Preventing caveolae formation in melanocytes results in increased production of intracellular cAMP and melanin pigments, but decreases cell protrusions, cell-cell contacts, pigment transfer and epidermis pigmentation. Altogether, our data establish that, in melanocytes, caveolae serve as key molecular hubs that couple signaling outputs from keratinocytes to mechanical plasticity. This process is crucial to maintain cell-cell contacts and intercellular communication, skin pigmentation and tissue homeostasis.
Severe anaemia complicating HIV in Malawi; multiple co-existing aetiologies are associated with high mortality
Authors: Huibers Minke HW , Bates Imelda , McKew Steve , Allain Theresa J , Coupland Sarah E. , Phiri Chimota , Phiri Kamija S. , van Hensbroek Michael Boele , Calis Job C
Published: June 2019

Background

Severe anaemia is a major cause of morbidity and mortality in HIV-infected adults living in resource-limited countries. Comprehensive data on the aetiology is lacking and needed to improve outcomes.

Methods

HIV-infected adults with severe (haemoglobin ≤70g/l) or very severe anaemia (haemoglobin ≤50 g/l) were recruited at Queen Elizabeth Central Hospital, Blantyre, Malawi. Fifteen potential causes of severe anaemia of anaemia and associations with anaemia severity and mortality were explored.

Results

199 patients were enrolled: 42.2% had very severe anaemia and 45.7% were on ART. Over two potential causes for anaemia were present in 94% of the patients; including iron deficiency (55.3%), underweight (BMI<20: 49.7%), TB-infection (41.2%) and unsuppressed HIV-infection (viral load >1000 copies/ml) (73.9%). EBV/CMV co-infection (16.5%) was associated with very severe anaemia (OR 2.8 95% CI 1.1-6.9). Overall mortality was high (53%; 100/199) with a median time to death of 16 days. Death was associated with folate deficiency (HR 2.2; 95% CI 1.2-3.8) and end stage renal disease (HR 3.2; 95% CI 1.6-6.2).

Conclusion

Mortality among severely anaemic HIV-infected adults is strikingly high. Clinicians must be aware of the urgent need for a multifactorial approach, including starting or optimising HIV treatment; considering TB treatment, nutritional support and attention to potential renal impairment.
Evaluation of Osteoinductivity of Different Calcium Phosphate and PTMC-Calcium Phosphate Composite Biomaterials in a Sheep Model
Authors: van Arnhem Arden L. , Zeng Ni , van Leeuwen Anne , Kuijer Roel , Bos Ruud. R.M. , Grijpma Dirk W.
Published: June 2019

Osteoinduction refers to de novo bone formation induced by biomaterials in places where physiologically no bone tissue is formed. Biomaterials with osteoinductive capacities have been shown to fill bone defects of critical sizes with ubiquitous new bone formation. Therefore, osteoinduction has been regarded as an important characteristic for biomaterials aiming at bone regeneration. In our study, we tested osteoinductive capacities of different calcium phosphate bioceramic particles, calcium phosphate scaffolds, and porous poly(trimethylene carbonate)(PTMC)-calcium phosphate composite scaffolds in a sheep model. Biphasic calcium phosphate (BCP) particles of 45-150 μm and 150-500 μm, microporous β-tricalcium phosphate (β-TCP) particles of 45-150 μm, non-microporous β-TCP particles of 45-150 μm and 150-500 μm, and porous β-TCP scaffolds were implanted in sheep long dorsal muscle for three and nine months. Likewise, porous composite scaffolds, in which BCP particles, microporous β-TCP particles and β-TCP particles, all of 45-150 μm, had been incorporated into PTMC matrices, were implanted in sheep long dorsal muscle for three and nine months. Porous PTMC scaffolds were implanted as controls. Abundant new bone formation was induced by BCP particles of both size ranges, the β-TCP scaffold was also able to induce new bone formation at both three and nine months follow up, while no new bone formation was induced by the other biomaterials. Implantation of the abovementioned biomaterials led to uneventful degradation of the PTMC matrices and the incorporated calcium phosphate particles, and provoked no obvious tissue reaction. Future studies are needed to determine the optimal composition of composite biomaterials based on PTMC and calcium phosphate to produce osteoinductive composites.
Nitrogen-fixing Klebsiella variicola in feces from herbivorous tortoises
Authors: Montes-Grajales Diana , Jiménez Berenice , Rogel Marco A. , Alagón Alejandro , Esturau-Escofet Nuria , Esquivel Baldomero , Martínez-Romero Julio , Martínez-Romero Esperanza
Published: June 2019

Animals feeding on plants (herbivorous) may have nutritional deficiencies and use bacterial nitrogen fixation in guts to compensate unbalanced diets with high carbon and low nitrogen. Using the acetylene reduction assay we searched for nitrogen fixation in the feces from several herbivorous animals in captivity. We detected acetylene reduction in feces from two African spurred tortoises, Centrochelys sulcata and in feces from six Gopherus berlandieri tortoises and isolated nitrogen-fixing klebsiellas from them. Additionally, we performed a gut metagenomic study with Illumina sequencing from a healthy Mexican G. berlandieri tortoise, and the nif genes identified in the feces microbiome matched those from Klebsiella variicola. Fecal bacterial composition from tortoises was similar to that reported from other reptilian guts.
Screening and functional analysis of differentially expressed genes in an animal model ofEBV-associated lymphomas
Authors: Zhang Yang , Wang Chengkun , Liu Liangzhuan , Peng Qiu , Gan Xiaoning , Xie Lu , Tan Meiying , He Rongfang , Tang Yunlian , Wu Yimou , Gan Runliang
Published: June 2019

Epstein-Barr virus(EBV) is an important human oncogenic virus. This paper is to explore how EBV induce malignant transformation of human lymphocytes and the related mechanism of lymphomagenesis. We have constructedhu-PBL/SCID chimeric miceand established a model of EBV-associated human-derived lymphomas. By using Agilent human whole genome microarray and a series of bioinformatic analyses, a total of 202 differentially expressed genes were screened from the EBV-induced lymphomas inhu-PBL/SCID mice, including 44 up-regulated and 158 down-regulated genes. Calculation of the rank score (RS) values of these genes in the HIPPIE protein interaction networks showed that topoisomerase II alpha (TOP2A), ubiquitin like with PHD and ring finger domains 1 (UHRF1), histone cluster 2 H2B family member E (HIST2H2BE), phosphoglycerate dehydrogenase (PHGDH), vinculin (VCL), insulin-like growth factor 1 receptor (IGF1R), Fos proto-oncogene (FOS), snail family transcriptional repressor 1 (SNAI1), PDZ binding kinase (PBK), and ring finger protein 144B (RNF144B) were the top 10 key node genes of EBV-induced lymphoma. In which, PBK, an up-regulated genes with the highest number of GO annotations, was verified by cellular function experiments and clinical lymphoma samples.

Author summary

EB virus is closely associated with human lymphoma and nasopharyngeal carcinoma. Since the susceptible hosts of EBV limit to human and cottontop tammarins, there are no appropriate animal models so far to study the EBV-associated oncogenesis. In our previous experiments, the EBV-associated lymphomas were induced inhu-PBL/SCID chimera(a new humanized mouse model). However, the cellular and molecular mechanisms of malignant transformation of normal human cells and tumor formation induced by EBV remain unclear. In this study, we examined and compared the gene expression profiles of EBV-induced lymphomas and normal human lymphocytes of the same origin in SCID mice. By constructing the gene-function relationship network, we preliminarily found that TOP2A, UHRF1, HIST2H2BE, PHGDH, VCL, IGF1R, FOS, SNAI1, PBK, and RNF144B may be the key genes in EBV-induced lymphomas. These findings suggest that the induction of lymphoma by EBV is a complex process that involves multiple genes and pathways.
CAT1/SLC7A1 acts as a cellular receptor for bovine leukemia virus infection
Authors: Bai Lanlan , Sato Hirotaka , Kubo Yoshinao , Wada Satoshi , Aida Yoko
Published: June 2019

Bovine leukemia virus (BLV) is the causative agent of enzootic bovine leukosis, the most common neoplastic disease of cattle, which is closely related to human T-cell leukemia viruses. BLV has spread worldwide and causes a serious problem for the cattle industry. The cellular receptor specifically binds with viral envelope glycoprotein (Env) and this attachment mediates cell fusion to lead virus entry. BLV Env reportedly binds to cationic amino acid transporter 1 (CAT1)/SLC7A1, but whether the CAT1/SLC7A1 is an actual receptor for BLV remains unknown. Here, we showed that CAT1 functioned as an infection receptor, interacting with BLV particles. Cells expressing undetectable CAT1 levels were resistant to BLV infection but became highly susceptible upon CAT1 overexpression. CAT1 exhibited specific binding to BLV particles on the cell surface and co-localized with the Env in endomembrane compartments and membrane. Knockdown of CAT1 in permissive cells significantly reduced binding to BLV particles and BLV infection. In addition, bovine serum with neutralizing activity from a BLV-infected cattle inhibited BLV particles. Expression of CAT1 from various species demonstrated no species-specificity for BLV infection, implicating CAT1 as a functional BLV receptor responsible for its broad host range. These findings provide insights for BLV infection and for developing new strategies for treating BLV and preventing its spread.

Author Summary

Bovine leukemia virus (BLV), which can infect a variety of animal species and induce lymphoma in cattle, is a member of the familyRetroviridae. BLV induces huge economic losses by not only lymphoma but also subclinical forms of the disease. In addition, BLV is frequently used as an animal model of human T-cell leukemia virus (HTLV), as BLV has many similar characteristics to HTLV. Thus, understanding BLV pathogenesis contribute to resolve not only BLV-but also HTLV-induced problems. Retroviral envelope glycoprotein (Env) is specifically recognized by the cellular receptor at cell surface, which induces a conformational changes between viral and cell membrane to entry. Thus, the elucidation of cellular receptor for BLV infection is very important for virus entry. However, the BLV receptor has not been identified yet. In the current study, we found that BLV Env protein binds to cationic amino acid transporter 1 (CAT1)/SLC7A1 at cell surface, artificial expression of CAT1 in CAT1-negative cells confers the cells susceptible to BLV infection, and CAT1-silencing significantly reduces BLV infection, concluding that CAT1 is the BLV receptor. These findings will have far reaching great advantages of insights in the retrovirus study.
ENVELOPED VIRUS-LIKE PARTICLES (eVLPs) EXPRESSING MODIFIED FORMS OF ZIKA VIRUS PROTEINS E AND NS1 PROTECT MICE FROM ZIKA VIRUS INFECTION
Authors: Fluckiger Anne-Catherine , Bozic Jasminka , Diress Abebaw , Ontsouka Barthelemy , Ahmed Tanvir , Ponce Amalia , Kirchmeier Marc , Diaz-Mitoma Francisco , Conlan Wayne , Anderson David E. , Soare Catalina
Published: June 2019

While Zika virus (ZIKV) infection induces mild disease in the majority of cases, it has been identified as responsible for microcephaly and severe neurological disorders in recent 2015-2016 outbreaks in South America and the Caribbean. Since then, several prophylactic vaccine strategies have been studied. Here, we describe the development of a ZIKV candidate vaccine consisting of bivalent enveloped virus-like particles (eVLPs) expressing a modified form of E and truncated NS1 (EG/NS1) proteins. In EG/NS1, the E transmembrane/cytoplasmic tail has been replaced with those domains from the VSV G protein and a β-domain of NS1 was fused in-frame to Gag from Moloney murine leukemia virus (MLV). Immunization of BALB/C mice demonstrated that bivalent EG/NS1 and monovalent EG eVLPs induced comparable levels of antibody (Ab) titers but that EG/NS1 induced much higher neutralizing activity, comparable to naturally acquired anti-ZIKV immunity. In contrast, monovalent NS1 eVLPs did not induce a significant anti-NS1 Ab response but promoted strong T cell immunity that was also elicited with EG/NS1 eVLPs. ZIKV challenge studies in C57BL/6-IFNαR−/−mice demonstrated that EG/NS1 eVLPs conferred 100% protection against clinical disease after ZIKV challenge compared to 80% protection after EG eVLP vaccination, with protection against challenge correlating with neutralizing antibody titers and overt signs of infection.

Author Summary

Zika virus has caused rapidly spreading epidemics with potentially severe neurological symptoms including microcephaly in new born babies. Rapid progress has been made with several candidate vaccines under clinical evaluation but no vaccine or treatment is yet available. In this context, we have produced and tested recombinant virus-like particles that incorporate one or two Zika virus proteins, E and NS1 that have been modified for optimal efficacy. Our immunogenicity studies in mice showed a synergistic effect of both proteins in the bivalent vaccine. NS1 induced a strong T cell response enhancing the neutralizing antibody production induced by the E protein. In challenge experiments, the bivalent vaccine protected 100% of mice from clinical signs of Zika virus infection. These products could be further used to explore Zika virus correlates of protection and evaluated as vaccine candidates.
Targeted poverty reduction under new structure
Authors: Wang Yuxin , Wang Luxia , Wu Huaqing , Zhu Yangguang , Shi Xing
Published: June 2019

Purpose

The purpose of this paper is to investigate the impact of social capital on the mental health of older adults in rural China. The authors also examine potential heterogeneous effects and two possible pathways from social capital increase to mental health improvement.

Design/methodology/approach

Based on a panel data of China Health and Retirement Longitudinal Study, this paper employs a fixed effect model to examine the impact of social capital on health. A two-stage instrumental variable approach is adopted to alleviate the issue of endogeneity.

Findings

Results demonstrate that social capital has improved the mental health of older adults in rural China significantly. The beneficial effect is stronger for female, people with lower income, aged people and mainly observed in the central and western regions. Social capital affects the mental health of rural older adults through raising the awareness of healthy behavior and lowering the searching cost of health-related information.

Practical implications

Social capital plays a vital role in improving the mental health of older adults in rural China and is necessary for the construction of beautiful countryside in China. The authority should increase the investment in both the hard and soft infrastructure to improve the mental health of rural residents and narrow the inequality in health status.

Originality/value

This study enriches the empirical literature on the relationship between social capital and mental health by providing new evidence from China. Also, we choose the social activities and communications of individuals to construct a standardized index for social capital, which can better capture the social capital at the individual level.
Customer-contact employees’ empowerment and customer performance
Authors: Berraies Sarra , Chtioui Rached , Chaher Mehrez
Published: June 2019

Purpose

The purpose of this paper is to explore the relationship between the customer-contact employees’ (CCE) empowerment and customer performance indicators, namely, perceived service quality (PSQ), customer satisfaction (CS), customer loyalty (CL) and word-of-mouth (WOM). The authors deepen the analysis by highlighting the mediating role of the dimensions of the customer relationship management (CRM) effectiveness in this link. The authors also investigate links between customer performance indicators.

Design/methodology/approach

An empirical study was carried out on the basis of a questionnaire administrated to a sample of 215 Tunisian bank CCE and 516 customers. Data analysis was performed using the structural equation modeling method.

Findings

Findings reveal that the CCE’ empowerment contributes to PSQ, CS and all the dimensions of CRM effectiveness which in turn are key factors of customer performance. This research also outlines the mediating role of two dimensions of the CRM effectiveness, namely, organizational commitment and customer experience between CCE’ empowerment and PSQ and CS, respectively. In addition, the study highlights that PSQ improves CS which is positively linked to CL. Finally, loyal customers tend to generate positive WOM.

Originality/value

Few studies have investigated the effects of the CCE’ empowerment on PSQ, CS, CL and positive WOM, especially in the banking sector. This research fills this gap by highlighting the mediating role of the dimensions of the CRM effectiveness in these links. This paper offers interesting insights to bankers by providing them with tools to improve their customers’ relationship. In this sense, banks must bet on the proximity of the CCE as a key asset that allows creating a real sense of closeness with customers and offers lighting to banks on how to create customized marketing approaches to ensure customer performance.