Showing papers by "David A. Jackson published in 2018"

The cardiac lymphatic system stimulates resolution of inflammation following myocardial infarction

Abstract: Myocardial infarction (MI) arising from obstruction of the coronary circulation engenders massive cardiomyocyte loss and replacement by non-contractile scar tissue, leading to pathological remodeling, dysfunction, and ultimately heart failure. This is presently a global health problem for which there is no effective cure. Following MI, the innate immune system directs the phagocytosis of dead cell debris in an effort to stimulate cell repopulation and tissue renewal. In the mammalian adult heart, however, the persistent influx of immune cells, coupled with the lack of an inherent regenerative capacity, results in cardiac fibrosis. Here, we reveal that stimulation of cardiac lymphangiogenesis with VEGF-C improves clearance of the acute inflammatory response after MI by trafficking immune cells to draining mediastinal lymph nodes (MLNs) in a process dependent on lymphatic vessel endothelial hyaluronan receptor 1 (LYVE-1). Deletion of Lyve1 in mice, preventing docking and transit of leukocytes through the lymphatic endothelium, results in exacerbation of chronic inflammation and long-term deterioration of cardiac function. Our findings support targeting of the lymphatic/immune cell axis as a therapeutic paradigm to promote immune modulation and heart repair.

The CLAVATA receptor FASCIATED EAR2 responds to distinct CLE peptides by signaling through two downstream effectors

Abstract: Like animals, plants are made up of many different types of cells, which descend from undifferentiated cells called stem cells. Thanks to these cells, plants are able to grow and develop throughout their lives. Stem cells live at the tips of the plant’s shoots and roots. They constantly divide to produce new cells to self-renew or replace specific plant cells in need of repair. Over time, they change – or differentiate – to go on to become part of tissues like leaves, roots, stems, shoots, flowers or fruits. To maintain a continuous pool of undifferentiated stem cells and to make sure that stem cells divide at the correct pace, neighbouring cells emit signals that control the activity of stem cells. The new stem cells that remain close to these ‘maintenance signals’ continue to behave like stem cells, but those displaced away begin to differentiate. Stem cells can receive many different types of signals, but how are these signals filtered and passed onto different places within the cell? To test this, Je, Xu et al. created maize plants that contained mutations in a number of known signalling molecules to see if these molecules used the same communication pathway. The results showed that stem cells could integrate the different signals. Even if the signals pass through the same receiver (a receptor protein called FASCIATED EAR2), each signal exits the receptor as a different message, and attaches to a different messenger protein to relay specific information about stem cell maintenance to the cell. A next step will be to test if other plants use the same signalling pathways in the same ways to send messages between cells. A better knowledge about stem cell signals in plants could help to develop more productive crops. Previous work has found that precise control of stem cell pathways can help breed crops with more seeds or bigger fruits. These kinds of changes have been selected naturally by humans since the dawn of civilization, but we need to accelerate these advances to help meet the needs of the growing world population and improve agricultural sustainability.

Lymphatic exosomes promote dendritic cell migration along guidance cues.

Abstract: Lymphatic endothelial cells (LECs) release extracellular chemokines to guide the migration of dendritic cells. In this study, we report that LECs also release basolateral exosome-rich endothelial vesicles (EEVs) that are secreted in greater numbers in the presence of inflammatory cytokines and accumulate in the perivascular stroma of small lymphatic vessels in human chronic inflammatory diseases. Proteomic analyses of EEV fractions identified >1,700 cargo proteins and revealed a dominant motility-promoting protein signature. In vitro and ex vivo EEV fractions augmented cellular protrusion formation in a CX3CL1/fractalkine-dependent fashion and enhanced the directional migratory response of human dendritic cells along guidance cues. We conclude that perilymphatic LEC exosomes enhance exploratory behavior and thus promote directional migration of CX3CR1-expressing cells in complex tissue environments.

Role of heterotrimeric Gα proteins in maize development and enhancement of agronomic traits.

Abstract: Plant shoot systems derive from the shoot apical meristems (SAMs), pools of stems cells that are regulated by a feedback between the WUSCHEL (WUS) homeobox protein and CLAVATA (CLV) peptides and receptors. The maize heterotrimeric G protein α subunit COMPACT PLANT2 (CT2) functions with CLV receptors to regulate meristem development. In addition to the sole canonical Gα CT2, maize also contains three eXtra Large GTP-binding proteins (XLGs), which have a domain with homology to Gα as well as additional domains. By either forcing CT2 to be constitutively active, or by depleting XLGs using CRISPR-Cas9, here we show that both CT2 and XLGs play important roles in maize meristem regulation, and their manipulation improved agronomic traits. For example, we show that expression of a constitutively active CT2 resulted in higher spikelet density and kernel row number, larger ear inflorescence meristems (IMs) and more upright leaves, all beneficial traits selected during maize improvement. Our findings suggest that both the canonical Gα, CT2 and the non-canonical XLGs play important roles in maize meristem regulation and further demonstrate that weak alleles of plant stem cell regulatory genes have the capacity to improve agronomic traits.

Sleep and asthma.

Abstract: Purpose of review There is a longstanding recognition of the detrimental effect of poorly controlled asthma on sleep, but recent years have seen a growing interest in how asthma and sleep may interact. This review examines the current evidence of relationships between asthma, sleep and sleep disorders. Recent findings Poor quality sleep and sleep disturbance is highly prevalent in asthmatic patients, and particularly in those with severe asthma. Impaired sleep quality correlates with worse asthma control and quality of life. Sleep disturbance in asthma may be related to due circadian variation in airway inflammation, but may also be related to specific sleep disorders. Obstructive sleep apnoea (OSA) appears to be significantly more common in asthmatic patients than nonasthmatic patients, and treatment of OSA with continuous positive airway pressure (CPAP) may lead to improved asthma-specific quality of life. Nocturnal CPAP may also be of benefit to asthmatic patients without OSA, potentially because of stretching of airway smooth muscle. Insomnia is also highly prevalent in severe asthma patients, and is associated with a history of poor asthma control and increased healthcare utilization. Summary Asthma, sleep and sleep disorders appear to have complex, but significant relationships. Prospective observational and controlled interventional studies are needed to quantify how addressing sleep difficulties may benefit asthma patients.

The potential of anti-infectives and immunomodulators as therapies for asthma and asthma exacerbations.

Abstract: Asthma is responsible for approximately 25,000 deaths annually in Europe despite available medicines that maintain asthma control and reduce asthma exacerbations. Better treatments are urgently needed for the control of chronic asthma and reduction in asthma exacerbations, the major cause of asthma mortality. Much research spanning >20 years shows a strong association between microorganisms including pathogens in asthma onset, severity and exacerbation, yet with the exception of antibiotics, few treatments are available that specifically target the offending pathogens. Recent insights into the microbiome suggest that modulating commensal organisms within the gut or lung may also be a possible way to treat/prevent asthma. The European Academy of Allergy & Clinical Immunology Task Force on Anti-infectives in Asthma was initiated to investigate the potential of anti-infectives and immunomodulators in asthma. This review provides a concise summary of the current literature and aimed to identify and address key questions that concern the use of anti-infectives and both microbe- and host-based immunomodulators and their feasibility for use in asthma.

TGFβ counteracts LYVE-1-mediated induction of lymphangiogenesis by small hyaluronan oligosaccharides.

Abstract: During tissue injury, inflammation, and tumor growth, enhanced production and degradation of the extracellular matrix glycosaminoglycan hyaluronan (HA) can lead to the accumulation of small HA (sHA) oligosaccharides. We have previously reported that accumulation of sHA in colorectal tumors correlates with lymphatic invasion and lymph node metastasis, and therefore, investigated here are the effects of sHA on the lymphatic endothelium. Using cultured primary lymphatic endothelial cells (LECs) and ex vivo and in vivo lymphangiogenesis assays, we found that in contrast to high-molecular-weight HA (HMW-HA), sHA of 4-25 disaccharides in length can promote the proliferation of LECs and lymphangiogenesis in a manner that is dependent on their size and concentration. At pathophysiologically relevant concentrations found in tumor interstitial fluid, sHA is pro-proliferative, acts synergistically with VEGF-C and FGF-2, and stimulates the outgrowth of lymphatic capillaries in ex vivo lymphangiogenesis assays. In vivo, intradermally injected sHA acts together with VEGF-C to increase lymphatic vessel density. Higher concentrations of sHA were found to induce expression of the anti-lymphangiogenic cytokine TGFβ in LECs, which serves to counter-regulate sHA-induced LEC proliferation and lymphangiogenesis. Using appropriate knockout mice and blocking antibodies, we found that the effects of sHA are mediated by the sialylated form of the lymphatic HA receptor LYVE-1, but not by CD44 or TLR-4. These data are consistent with the notion that accumulation of sHA in tumors may contribute to tumor-induced lymphangiogenesis, leading to increased dissemination to regional lymph nodes. KEY MESSAGES : sHA promotes lymphangiogenesis primarily through increased LEC proliferation sHA induces proliferation in a narrow concentration window due to upregulated TGFβ Smaller HA oligosaccharides more potently induce proliferation than larger ones VEGF-C and FGF-2-induced LEC proliferation and lymphangiogenesis is augmented by sHA Sialylated LYVE-1, but not CD44 or TLR-4, mediate the effects of sHA on LEC.

An Efficient Cell Sorting Protocol for Maize Protoplasts

Abstract: Maize is one the most widely cultivated crops worldwide and an important model system for the study of genetics and cytogenetics. Although the availability of a genome sequence has enabled new quantitative genomic studies, developing methods to isolate specific types of cells will enable useful approaches for transcriptomic analysis in the crop plant. Fluorescence-activated cell sorting (FACS) is a powerful technique for cell isolation and the study of transcriptional profiles from specific cell populations. The use of FACS on plant cells requires the generation of protoplasts by tissue digestion and cell wall removal. Although some protocols are available, they mainly focus on dicot species and obtaining sufficient protoplasts from inner tissue layers has been challenging in both monocots and dicots. Here, we report a new protocol that dramatically increases protoplast yield from maize for subsequent cell isolation by FACS. This protocol is efficient in generating protoplasts from root and shoot inner layers and can also be applied successfully to Arabidopsis thaliana. © 2018 by John Wiley & Sons, Inc.

Prioritisation of oncology therapeutic targets using CRISPR-Cas9 screening

Abstract: Functional genomics approaches can overcome current limitations that hamper oncology drug development such as lack of robust target identification and clinical efficacy. Here we performed genome-scale CRISPR-Cas9 screens in 204 human cancer cell lines from 12 cancer-types and developed a data-driven framework to prioritise cancer therapeutic candidates. We integrated gene cell fitness effects with genomic biomarkers and target tractability for drug development to systematically prioritise new oncology targets in defined tissues and genotypes. Furthermore, we took one of our most promising dependencies, Werner syndrome RecQ helicase, and verified it as a candidate target for tumours with microsatellite instability. Our analysis provides a comprehensive resource of cancer dependencies, a framework to prioritise oncology targets, and nominates specific new candidates. The principles described in this study can transform the initial stages of the drug development process contributing to a new, diverse and more effective portfolio of oncology targets.

Detection of MAPK3/6 Phosphorylation During Hypersensitive Response (HR)-Associated Programmed Cell Death in Plants.

Abstract: Programmed cell death (PCD) is an essential component of development, biotic and abiotic responses. Hypersensitive response (HR)-associated cell death activated under pathogen attack is one of the most dramatic manifestations of PCD in plants. Signal transduction through mitogen-activated protein kinase (MAPK) cascades, a very conserved signaling pathway across eukaryotes, is a core mediator for HR-associated PCD. Therefore, monitoring MAPK activation enables the mechanisms underlying HR-associated PCD to be elucidated. Here, we describe the use of a phosphorylation-specific MAPK3/6 antibody to monitor the activation of MAPK3/6 during HR-associated PCD. The technique may be adapted for use in other types of PCD.

S80 A comparison of the clinical response to mepolizumab and benralizumab at 4 weeks

Abstract: Background Mepolizumab and benralizumab are biologic therapies licensed for the treatment of severe eosinophilic asthma. Mepolizumab is a serum neutralising antibody against interleukin (IL)−5 whereas benralizumab targets the IL-5 receptor. In clinical trials both therapies lead to similar reductions in exacerbation frequency. In the absence of head-to-head data we sought to compare the early clinical and inflammatory response to these treatments. Methods A retrospective review of adult patients with severe eosinophilic asthma treated with mepolizumab and benralizumab at Guy’s Severe Asthma Centre was carried out. Baseline characteristics and change from baseline at 4 weeks in blood eosinophil count, FeNO, FEV1 and ACQ6 was compared between patients treated with mepolizumab and those receiving benralizumab. Results Seventy-six patients including 38 treated with mepolizumab (55% female, mean age 54±11) and 38 treated with benralizumab (61% female, mean age 51±12) were included in this analysis. An equal number of patients in each group (28/38) were on maintenance oral corticosteroid treatment. The baseline blood eosinophil counts, FeNO, FEV1 and ACQ6 levels were not statistically different between groups. At 4 weeks, the absolute reduction in blood eosinophil count was 297±505 cells/mcL for benralizumab vs 166±207 cells/mcL for mepolizumab. The magnitude of this reduction was not statistically different between treatments (p=0.14), however, all 38 patients treated with benralizumab had undetectable blood eosinophils at 4 weeks compared to 19/38 in the mepolizumab group (p Conclusion A retrospective review of patients treated with either mepolizumab or benralizumab highlights non-significant trends towards improved ACQ6 and FEV1 with benralizumab at the time of the second dose at 4 weeks. This may reflect a more potent eosinophil-depleting mechanism of action with benralizumab.

P48 The ‘T2-low’ asthma phenotype: could it just be T2-high asthma treated with corticosteroids?

Abstract: Introduction In recent years patients with asthma have been dichotomised by the degree of their type 2 (T2) airways inflammation into ‘T2-high’ and ‘T2-low’ phenotypes. Whilst published reports suggest that 50% of asthma is T2-low, the majority of patients described in these studies are on high dose ICS or OCS. Given that corticosteroids suppress T2 inflammation the true prevalence of T2 low asthma may be lower than reported once steroid doses have been weaned. Method A retrospective review of asthma referrals to a tertiary asthma clinic was performed. T2 status was recorded on initial assessment and at follow-up using the blood eosinophil (Eos) count and FeNO level. Patients were identified as T2-high if Eos ≥300 cells/mcL or FeNO ≥50 ppb, T2-Low if Eos Results 200 adult patients with a diagnosis of difficult asthma were identified. At initial assessment 71% were T2-High, 18.5% were T2-Low, and 10.5% were T2-Intermediate. Across the two visits 84% were T2-High on at least one visit and 8% were T2-Low on both visits. The mean ICS dose in the T2-Low group was 1740 mcg BDP equivalent/day. 81.3% of T2-Low patients had relevant co-morbidities including dysfunctional breathing (37.5%), obesity (37.5%), gastroesophageal reflux (25%) and VCD (12.5%). Conclusion Only 8% of severe asthmatics appear persistently T2-Low once their ICS or OCS dose has been optimised. These patients had several co-morbidities that could explain their ongoing symptoms and usage of high levels of treatment. In view of the well-recognised T2-dampening effects of high dose inhaled corticosteroids, the absence of T2 inflammation in these patients may simply reflect overuse of anti-inflammatory treatment in highly symptomatic patients, rather than a true non-T2 inflammatory endotype of asthma.

S79 Predictors of response to mepolizumab in oral corticosteroid dependent severe asthma

Abstract: Introduction Patients with severe eosinophilic asthma (SEA) requiring maintenance oral corticosteroid (mOCS) to control their disease represent the most severe end of the asthmatic spectrum. Mepolizumab is a serum neutralising antibody against interleukin (IL)−5 with proven steroid-sparing efficacy in SEA requiring mOCS. Despite the appropriate phenotype, mepolizumab is not successful in all SEA patients, however to date no published data relating to possible responder characteristics in SEA exists to help guide physicians. Methods A retrospective review of patients with SEA on mOCS who received mepolizumab for one year was carried out at a single tertiary asthma centre. Patients were divided into responders (defined as those who achieved ≥50% reduction in mOCS dose by 12 months) and non-responders ( Results Fifty-two patients (61.5% female, mean age 52.9) with SEA on mOCS were included. 38/52 (73%) achieved ≥50% reduction in mOCS and were termed responders at one year. At baseline, compared to non-responders, the responder group had a significantly lower daily mOCS dose, better asthma control and were significantly less likely to be atopic (all p Conclusion In SEA requiring mOCS, a higher baseline OCS dose, higher ACQ6 and atopic status appear to be associated with a poorer response to mepolizumab. The trend observed with regards to higher BMI may suggest that the current 100 mg dose is insufficient for some patients. Further research is needed to understand whether the weight-based anti-IL-5 monoclonal antibody (mAb) reslizumab or the anti-IL5R mAb benralizumab may be effective in patients with SEA who have a suboptimal response to mepolizumab.

Learning from CIK plants.

Abstract: The stem cell niche in plant shoots is maintained by carefully orchestrated feedback between a series of CLAVATA (CLV) receptors and their ligand CLV3, and the transcription factor WUSCHEL. A new clade of co-receptors, CLV3-insensitive receptor kinases (CIKs), provides an important missing link in CLV signalling.

Compositions and methods for generating weak alleles in plants

Abstract: Provided herein are compositions and methods for generating alleles of genes of interest in plants In some aspects, libraries of plants or seeds are provided that comprise an expression construct comprising a RNA-guided endonuclease (eg, a Cas9 endonuclease) and multiple different guide RNAs that target regions of the gene of interest, such as regulatory regions

Application of fiber Bragg grating sensors and a fiber optic laser Doppler vibrometer for hypervelocity impacts

Abstract: Hypervelocity impacts occur frequently in space due to dust that occurs naturally from comets or other space debris often called meteoroids; other debris is man-made and can have disastrous effects on spacecraft. Even though the particle may have a very small mass its momentum can be extremely high and destroy space craft. It is therefore vitally important to simulate the effects of hypervelocity impacts on vulnerable areas of satellites and space stations. A two stage light gas gun was previously developed for this purpose. In this paper we briefly describe two fiber optic based impact measurement systems that were tested at the light gas gun facility at the University of Kent to establish that they could provide data that could not be obtained by any other technique.

Long axial imaging range using conventional swept source lasers in optical coherence tomography via re-circulation loops

Abstract: Typically, swept source optical coherence tomography (SS-OCT) imaging instruments are capable of a longer axial range than their camera based (CB) counterpart. However, there are still various applications that would take advantage for an extended axial range. In this paper, we propose an interferometer configuration that can be used to extend the axial range of the OCT instruments equipped with conventional swept-source lasers up to a few cm. In this configuration, the two arms of the interferometer are equipped with adjustable optical path length rings. The use of semiconductor optical amplifiers in the two rings allows for compensating optical losses hence, multiple paths depth reflectivity profiles (Ascans) can be combined axially. In this way, extremely long overall axial ranges are possible. The use of the recirculation loops produces an effect equivalent to that of extending the coherence length of the swept source laser. Using this approach, the achievable axial imaging range in SS-OCT can reach values well beyond the limit imposed by the coherence length of the laser, to exceed in principle many centimeters. In the present work, we demonstrate axial ranges exceeding 4 cm using a commercial swept source laser and reaching 6 cm using an “in-house” swept source laser. When used in a conventional set-up alone, both these lasers can provide less than a few mm axial range.