bluuebunny/crossref_metadata_2025_split huggingface dataset:
Minocycline alters expression of inflammatory markers in autonomic brain areas and ventilatory responses induced by acute hypoxia
Authors: Silva Talita M. , Chaar Laiali J. , Silva Reinaldo C. , Takakura Ana C. , Câmara Niels O. , Antunes Vagner R. , Moreira Thiago S. 
Published: March 2018

New Findings
What is the central question of this study?
Microglia are presumed to be the source of inflammatory mediators that contribute to hypoxia‐induced neuroinflammation. However, the relationship between microglial activity during hypoxia and inflammatory responses in specific autonomic brain regions is not well understood. Therefore, we hypothesized that acute hypoxia initiates an immune response in the central nervous system elicited by an increased expression of inflammatory mediators in specific brain areas related to autonomic control.

What is the main finding and its importance?
Acute hypoxia initiated neuroinflammatory mechanisms specifically in brain autonomic nuclei responsible for cardiorespiratory control, i.e. the rostral ventrolateral medulla and paraventricular nucleus of the hypothalamus. Our findings emphasize the importance of microglia for the maintenance of autonomic adjustments during physiological challenges, such as hypoxia, or during cardiorespiratory reflex activation elicited by the arterial chemoreceptors.

AbstractProlonged and continuous exposure of mammals to a low oxygen environment (chronic hypoxia) elicits remarkable morphological and physiological adjustments. These include altered gene expression, increased peripheral chemosensitivity, enhanced respiratory drive and sympathoexcitation. The current study examines the hypothesis that acute hypoxia (AH) initiates an immune response in the central nervous system elicited by an increased expression of inflammatory mediators in specific brain areas related to autonomic control. Male Wistar rats pretreated with vehicle or minocycline (30 mg kg−1 day−1 for 5 days) were subjected to AH (8% O2, balance N2) or normoxia (21% O2) for 3 h. AH increased interleukin (IL)‐6, IL‐1β and matrix metalloprotease 9 (MMP9) mRNA expression in the paraventricular nucleus of the hypothalamus (PVH) and rostral ventrolateral medulla (RVLM) and tumour necrosis factor α (TNFα) in the RVLM. Treatment with minocycline, an inhibitor of microglial activation, decreased IL‐1β, TNFα and MMP9 mRNA expression in the RVLM, and increased IL‐6 mRNA expression in the RVLM and PVH of rats exposed to AH. Minocycline treatment also elicited a decrease in the number of activated neurons in the RVLM/C1 neurons (expressed as Fos+/tyrosine hydroxylase+), the number of Fos‐activated neurons in the PVH and the increase in ventilation elicited by AH. When viewed together, these results suggest that AH modulates the expression of inflammatory mediators in autonomic brain nuclei that may be involved in the responses to chemoreceptor activation.
Age‐associated impairments in contraction‐induced rapid‐onset vasodilatation within the forearm are independent of mechanical factors
Authors: Hughes William E. , Kruse Nicholas T. , Casey Darren P. 
Published: March 2018

New Findings
What is the central question of this study?
We examined whether the mechanical contribution to contraction‐induced rapid‐onset vasodilatation (ROV) differed with age and whether ROV is associated with peripheral artery stiffness. Furthermore, we examined how manipulation of perfusion pressure modulates ROV in young and older adults.

What is the main finding and its importance?
The mechanical contribution to ROV is similar in young and older adults. Conversely, peripheral arterial stiffness is not associated with ROV. Enhancing perfusion pressure augments ROV to a similar extent in young and older adults. These results suggest that age‐related attenuations in ROV are not attributable to a mechanical component and that ROV responses are independent of peripheral artery stiffness.

AbstractContraction‐induced rapid‐onset vasodilatation (ROV) is modulated by perfusion and transmural pressure in young adults; however, this effect remains unknown in older adults. The present study examined the mechanical contribution to ROV in young versus older adults, the influence of perfusion pressure and whether these responses are associated with arterial stiffness. Forearm vascular conductance (in millilitres per minute per 100 mmHg) was measured in 12 healthy young (24 ± 4 years old) and 12 older (67 ± 3 years old) adults during: (i) single dynamic contractions at 20% of maximal voluntary contraction; and (ii) single external mechanical compression of the forearm (200 mmHg) positioned above, at and below heart level. Carotid–radial pulse‐wave velocity characterized upper limb arterial stiffness. Total ROV responses to single muscle contractions and single external mechanical compressions were attenuated in older adults at heart level (P < 0.05); however, the relative mechanical contribution to contraction‐induced peak (46 ± 14 versus 40 ± 18%; P = 0.21) and total (37 ± 21 versus 32 ± 18%; P = 0.27) responses were not different between young and older adults. Reducing or enhancing perfusion pressure altered ROV responses to a similar extent between young and older adults (P < 0.05). Upper limb arterial stiffness was not associated with peak (r = 0.02; P = 0.93) or total vascular conductance (r = −0.01; P = 0.96) in the group as a whole. Our data suggest that: (i) age‐associated attenuations in ROV are not attributable to a mechanical component; (ii) enhancing perfusion pressure augments ROV to a similar extent between young and older adults; and (iii) basal upper limb arterial stiffness is not associated with the vasodilator responses after a single skeletal muscle contraction in young and older adults.
A role for focal adhesion kinase in facilitating the contractile responses of murine gastric fundus smooth muscles
Authors: Xie Yeming , Han Koon Hee , Grainger Nathan , Li Wen , Corrigan Robert D. , Perrino Brian A. 
Published: March 2018

Key points
Activation of focal adhesion kinase (FAK) by integrin signalling facilitates smooth muscle contraction by transmitting the force generated by myofilament activation to the extracellular matrix and throughout the smooth muscle tissue.
Here we report that electrical field stimulation (EFS) of cholinergic motor neurons activates FAK in gastric fundus smooth muscles, and that FAK activation by EFS is atropine‐sensitive but nicardipine‐insensitive. PDBu and calyculin A contracted gastric fundus muscles Ca2+‐independently and also activated FAK.
Inhibition of FAK activation inhibits the contractile responses evoked by EFS, and inhibits CPI‐17 phosphorylation at T38.
This study indicates that mechanical force or tension is sufficient to activate FAK, and that FAK appears to be involved in the activation of the protein kinase C–CPI‐17 Ca2+ sensitization pathway in gastric fundus smooth muscles.
These results reveal a novel role for FAK in gastric fundus smooth muscle contraction by facilitating CPI‐17 phosphorylation.
AbstractSmooth muscle contraction involves regulating myosin light chain phosphorylation and dephosphorylation by myosin light chain kinase and myosin light chain phosphatase. C‐kinase potentiated protein phosphatase‐1 inhibitor of 17 kDa (CPI‐17) and myosin phosphatase targeting subunit of myosin light‐chain phosphatase (MYPT1) are crucial for regulating gastrointestinal smooth muscle contraction by inhibiting myosin light chain phosphatase. Integrin signalling involves the dynamic recruitment of several proteins, including focal adhesion kinase (FAK), to focal adhesions. FAK tyrosine kinase activation is involved in cell adhesion to the extracellular matrix via integrin signalling. FAK participates in linking the force generated by myofilament activation to the extracellular matrix and throughout the smooth muscle tissue. Here, we show that cholinergic stimulation activates FAK in gastric fundus smooth muscles. Electrical field stimulation in the presence of Nω‐nitro‐l‐arginine methyl ester and MRS2500 contracted gastric fundus smooth muscle strips and increased FAK Y397 phosphorylation (pY397). Atropine blocked the contractions and prevented the increase in pY397. The FAK inhibitor PF‐431396 inhibited the contractions and the increase in pY397. PF‐431396 also inhibited the electrical field stimulation‐induced increase in CPI‐17 T38 phosphorylation, and reduced MYPT1 T696 and T853, and myosin light chain S19 phosphorylation. Ca2+ influx was unaffected by PF‐431396. Nicardipine inhibited the contractions but had no effect on the increase in pY397. Phorbol 12,13‐dibutyrate or calyculin A contracted gastric fundus smooth muscle strips Ca2+ independently and increased pY397. Our findings suggest that FAK is activated by mechanical forces during contraction and reveal a novel role of FAK in the regulation of CPI‐17 phosphorylation.
The Origin of Chromosomal Replication Is Asymmetrically Positioned on the Mycobacterial Nucleoid, and the Timing of Its Firing Depends on HupB
Authors: Hołówka Joanna , Trojanowski Damian , Janczak Mateusz , Jakimowicz Dagmara , Zakrzewska-Czerwińska Jolanta 
Published: March 2018

ABSTRACTThe bacterial chromosome undergoes dynamic changes in response to ongoing cellular processes and adaptation to environmental conditions. Among the many proteins involved in maintaining this dynamism, the most abundant is the nucleoid-associated protein (NAP) HU. In mycobacteria, the HU homolog, HupB, possesses an additional C-terminal domain that resembles that of eukaryotic histones H1/H5. Recently, we demonstrated that the highly abundant HupB protein occupies the entirety of theMycobacterium smegmatischromosome and that the HupB-binding sites exhibit a bias from the origin (oriC) to the terminus (ter). In this study, we used HupB fused with enhanced green fluorescent protein (EGFP) to perform the first analysis of chromosome dynamics and to track theoriCand replication machinery directly on the chromosome during the mycobacterial cell cycle. We show that the chromosome is located in an off-center position that reflects the unequal division and growth of mycobacterial cells. Moreover, unlike the situation inE. coli, the sisteroriCregions ofM. smegmatismove asymmetrically along the mycobacterial nucleoid. Interestingly, in this slow-growing organism, the initiation of the next round of replication precedes the physical separation of sister chromosomes. Finally, we show that HupB is involved in the precise timing of replication initiation.IMPORTANCEAlthough our view of mycobacterial nucleoid organization has evolved considerably over time, we still know little about the dynamics of the mycobacterial nucleoid during the cell cycle. HupB is a highly abundant mycobacterial nucleoid-associated protein (NAP) with an indispensable histone-like tail. It was previously suggested as a potential target for antibiotic therapy against tuberculosis. Here, we fused HupB with enhanced green fluorescent protein (EGFP) to study the dynamics of the mycobacterial chromosome in real time and to monitor the replication process directly on the chromosome. Our results reveal that, unlike the situation inEscherichia coli, the nucleoid of an apically growing mycobacterium is positioned asymmetrically within the cell throughout the cell cycle. We show that HupB is involved in controlling the timing of replication initiation. Since tuberculosis remains a serious health problem, studies concerning mycobacterial cell biology are of great importance.
Defining the Transcriptional Landscape during Cytomegalovirus Latency with Single-Cell RNA Sequencing
Authors: Shnayder Miri , Nachshon Aharon , Krishna Benjamin , Poole Emma , Boshkov Alina , Binyamin Amit , Maza Itay , Sinclair John , Schwartz Michal , Stern-Ginossar Noam 
Published: March 2018

ABSTRACTPrimary infection with human cytomegalovirus (HCMV) results in a lifelong infection due to its ability to establish latent infection, with one characterized viral reservoir being hematopoietic cells. Although reactivation from latency causes serious disease in immunocompromised individuals, our molecular understanding of latency is limited. Here, we delineate viral gene expression during natural HCMV persistent infection by analyzing the massive transcriptome RNA sequencing (RNA-seq) atlas generated by the Genotype-Tissue Expression (GTEx) project. This systematic analysis reveals that HCMV persistencein vivois prevalent in diverse tissues. Notably, we find only viral transcripts that resemble gene expression during various stages of lytic infection with no evidence of any highly restricted latency-associated viral gene expression program. To further define the transcriptional landscape during HCMV latent infection, we also used single-cell RNA-seq and a tractable experimental latency model. In contrast to some current views on latency, we also find no evidence for any highly restricted latency-associated viral gene expression program. Instead, we reveal that latency-associated gene expression largely mirrors a late lytic viral program, albeit at much lower levels of expression. Overall, our work has the potential to revolutionize our understanding of HCMV persistence and suggests that latency is governed mainly by quantitative changes, with a limited number of qualitative changes, in viral gene expression.IMPORTANCEHuman cytomegalovirus is a prevalent pathogen, infecting most of the population worldwide and establishing lifelong latency in its hosts. Although reactivation from latency causes significant morbidity and mortality in immunocompromised hosts, our molecular understanding of the latent state remains limited. Here, we examine the viral gene expression during natural and experimental latent HCMV infection on a transcriptome-wide level. In contrast to the classical views on herpesvirus latency, we find no evidence for a restricted latency-associated viral gene expression program. Instead, we reveal that latency gene expression largely resembles a late lytic viral profile, albeit at much lower levels of expression. Taken together, our data transform the current view of HCMV persistence and suggest that latency is mainly governed by quantitative rather than qualitative changes in viral gene expression.
Predicting the Susceptibility of Meningococcal Serogroup B Isolates to Bactericidal Antibodies Elicited by Bivalent rLP2086, a Novel Prophylactic Vaccine
Authors: McNeil Lisa K. , Donald Robert G. K. , Gribenko Alexey , French Roger , Lambert Nathaniel , Harris Shannon L. , Jones Thomas R. , Li Sheng , Zlotnick Gary , Vogel Ulrich , Claus Heike , Abad Raquel , Vazquez Julio A. , Borrow Ray , Findlow Jamie , Taha Muhamed-Kheir , Deghmane Ala-Eddine , Caugant Dominique A. , Kriz Paula , Musilek Martin , Wang Xin , Vuong Jeni , Mayer Leonard W. , Pride Michael W. , Jansen Kathrin U. , Anderson Annaliesa S. 
Published: March 2018

ABSTRACT

Bivalent rLP2086 (Trumenba), a vaccine for prevention of
Neisseria meningitidis
serogroup B (NmB) disease, was licensed for use in adolescents and young adults after it was demonstrated that it elicits antibodies that initiate complement-mediated killing of invasive NmB isolates in a serum bactericidal assay with human complement (hSBA). The vaccine consists of two factor H binding proteins (fHBPs) representing divergent subfamilies to ensure broad coverage. Although it is the surrogate of efficacy, an hSBA is not suitable for testing large numbers of strains in local laboratories. Previously, an association between the
in vitro
fHBP surface expression level and the susceptibility of NmB isolates to killing was observed. Therefore, a flow cytometric meningococcal antigen surface expression (MEASURE) assay was developed and validated by using an antibody that binds to all fHBP variants from both fHBP subfamilies and accurately quantitates the level of fHBP expressed on the cell surface of NmB isolates with mean fluorescence intensity as the readout. Two collections of invasive NmB isolates (
n
= 1,814,
n
= 109) were evaluated in the assay, with the smaller set also tested in hSBAs using individual and pooled human serum samples from young adults vaccinated with bivalent rLP2086. From these data, an analysis based on fHBP variant prevalence in the larger 1,814-isolate set showed that >91% of all meningococcal serogroup B isolates expressed sufficient levels of fHBP to be susceptible to bactericidal killing by vaccine-induced antibodies.

IMPORTANCE
Bivalent rLP2086 (Trumenba) vaccine, composed of two factor H binding proteins (fHBPs), was recently licensed for the prevention of
N. meningitidis
serogroup B (NmB) disease in individuals 10 to 25 years old in the United States. This study evaluated a large collection of NmB isolates from the United States and Europe by using a flow cytometric MEASURE assay to quantitate the surface expression of the vaccine antigen fHBP. We find that expression levels and the proportion of strains above the level associated with susceptibility in an hSBA are generally consistent across these geographic regions. Thus, the assay can be used to predict which NmB isolates are susceptible to killing in the hSBA and therefore is able to demonstrate an fHBP vaccine-induced bactericidal response. This work significantly advances our understanding of the potential for bivalent rLP2086 to provide broad coverage against diverse invasive-disease-causing NmB isolates.
Fecal Microbiota Signatures Are Associated with Response to Ustekinumab Therapy among Crohn’s Disease Patients
Authors: Doherty Matthew K. , Ding Tao , Koumpouras Charlie , Telesco Shannon E. , Monast Calixte , Das Anuk , Brodmerkel Carrie , Schloss Patrick D. 
Published: March 2018

ABSTRACTThe fecal microbiota is a rich source of biomarkers that have previously been shown to be predictive of numerous disease states. Less well studied is the effect of immunomodulatory therapy on the microbiota and its role in response to therapy. This study explored associations between the fecal microbiota and therapeutic response of Crohn’s disease (CD) patients treated with ustekinumab (UST; Stelara) in the phase 2 CERTIFI study. Using stool samples collected over the course of 22 weeks, the composition of these subjects’ fecal bacterial communities was characterized by sequencing the 16S rRNA gene. Subjects in remission could be distinguished from those with active disease 6 weeks after treatment using random forest models trained on subjects’ baseline microbiota and clinical data (area under the curve [AUC] of 0.844, specificity of 0.831, sensitivity of 0.774). The most predictive operational taxonomic units (OTUs) that were ubiquitous among subjects were affiliated withFaecalibacteriumandEscherichiaorShigella. The median baseline community diversity in subjects in remission 6 weeks after treatment was 1.7 times higher than that in treated subjects with active disease (P= 0.020). Their baseline community structures were also significantly different (P= 0.017). Two OTUs affiliated withFaecalibacterium(P= 0.003) andBacteroides(P= 0.022) were significantly more abundant at baseline in subjects who were in remission 6 weeks after treatment than those with active CD. The microbiota diversity of UST-treated clinical responders increased over the 22 weeks of the study, in contrast to nonresponsive subjects (P= 0.012). The observed baseline differences in fecal microbiota and changes due to therapeutic response support the potential for the microbiota as a response biomarker.IMPORTANCECD is a global health concern, with increasing incidence and prevalence, causing large economic and health care impacts. Finding prognostic biomarkers that give clinicians the ability to identify patients more likely to respond to CD treatment at diagnosis will reduce the time subjects receive drugs that are unlikely to be beneficial. OTUs associated with remission after treatment induction, especiallyFaecalibacterium, could be biomarkers for successful UST treatment of anti-tumor necrosis factor alpha (anti-TNF-α) refractory CD patients. More broadly, these results suggest that the fecal microbiota could be a useful noninvasive biomarker for directing or monitoring the treatment of gastrointestinal diseases.
Conditional Protein Splicing Switch in Hyperthermophiles through an Intein-Extein Partnership
Authors: Lennon Christopher W. , Stanger Matthew , Banavali Nilesh K. , Belfort Marlene 
Published: March 2018

ABSTRACT

Inteins are intervening proteins that undergo an autocatalytic splicing reaction that ligates flanking host protein sequences termed exteins. Some intein-containing proteins have evolved to couple splicing to environmental signals; this represents a new form of posttranslational regulation. Of particular interest is RadA from the archaeon
Pyrococcus horikoshii
, for which long-range intein-extein interactions block splicing, requiring temperature and single-stranded DNA (ssDNA) substrate to splice rapidly and accurately. Here, we report that splicing of the intein-containing RadA from another archaeon,
Thermococcus sibericus
, is activated by significantly lower temperatures than is
P. horikoshii
RadA, consistent with differences in their growth environments. Investigation into variations between
T. sibericus
and
P. horikoshii
RadA inteins led to the discovery that a nonconserved region (NCR) of the intein, a flexible loop where a homing endonuclease previously resided, is critical to splicing. Deletion of the NCR leads to a substantial loss in the rate and accuracy of
P. horikoshii
RadA splicing only within native exteins. The influence of the NCR deletion can be largely overcome by ssDNA, demonstrating that the splicing-competent conformation can be achieved. We present a model whereby the NCR is a flexible hinge which acts as a switch by controlling distant intein-extein interactions that inhibit active site assembly. These results speak to the repurposing of the vestigial endonuclease loop to control an intein-extein partnership, which ultimately allows exquisite adaptation of protein splicing upon changes in the environment.

IMPORTANCE
Inteins are mobile genetic elements that interrupt coding sequences (exteins) and are removed by protein splicing. They are abundant elements in microbes, and recent work has demonstrated that protein splicing can be controlled by environmental cues, including the substrate of the intein-containing protein. Here, we describe an intein-extein collaboration that controls temperature-induced splicing of RadA from two archaea and how variation in this intein-extein partnership results in fine-tuning of splicing to closely match the environment. Specifically, we found that a small sequence difference between the two inteins, a flexible loop that likely once housed a homing endonuclease used for intein mobility, acts as a switch to control intein-extein interactions that block splicing. Our results argue strongly that some inteins have evolved away from a purely parasitic lifestyle to control the activity of host proteins, representing a new form of posttranslational regulation that is potentially widespread in the microbial world.