Duffy antigen receptor for chemokines and CXCL5 are essential for the recruitment of neutrophils in a multicellular model of rheumatoid arthritis synovium

OBJECTIVE: The role of chemokines and their transporters are poorly described in rheumatoid arthritis (RA). Evidence suggests that CXCL5 plays an important role as it is abundant in RA tissue and its neutralization moderates joint damage in animal models of arthritis. The chemokine transporter, Duffy Antigen Receptor for Chemokines (DARC), is also upregulated in early RA. Here we investigate the role of CXCL5 and DARC in regulating neutrophil recruitment using an in vitro model of the RA synovium. METHODS: To model the RA synovium, rheumatoid fibroblasts (RAF) were cocultured with endothelial cells (EC) for 24h. Gene expression in cocultured cells was investigated using TaqMan gene arrays. Roles of CXCL5 and DARC were determined by incorporating cocultures into a flow-based adhesion assay, where their function was demonstrated by blocking neutrophil recruitment with neutralizing reagents. RESULTS: EC-RAF coculture induced chemokine expression in both cell types. While CXC chemokines were modestly upregulated in EC, CXCL1, CXCL5 and CXCL8 expression were greatly increased in RAF. RAF also promoted the recruitment of flowing neutrophils to EC. Anti-CXCL5 antibody abolished neutrophil recruitment by neutralizing CXCL5 expressed on EC, or when used to immuno-deplete coculture conditioned medium. DARC was also induced on EC by coculture and an anti-Fy6 antibody or siRNA targeting of DARC expression effectively abolished neutrophil recruitment. CONCLUSION: For the first time in a model of human disease, the function of DARC has been demonstrated as essential for editing the chemokine signals presented by EC and for promoting unwanted leukocyte recruitment

A novel mechanism of neutrophil recruitment in a co-culture model of the rheumatoid synovium

OBJECTIVE: Rheumatoid arthritis (RA) is classically thought of as a Th1, T lymphocyte–driven disease of the adaptive immune system. However, cells of the innate immune system, including neutrophils, are prevalent within the diseased joint, and accumulate in large numbers. This study was undertaken to determine whether cells of the rheumatoid stromal microenvironment could establish an inflammatory environment in which endothelial cells are conditioned in a disease-specific manner to support neutrophil recruitment. METHODS: Human umbilical vein endothelial cells (ECs) and fibroblasts isolated from the synovium or skin of RA patients were established in coculture on opposite sides of porous transwell filters. After 24 hours of EC conditioning, the membranes were incorporated into a parallel-plate, flow-based adhesion assay and levels of neutrophil adhesion to ECs were measured. RESULTS: ECs cocultured with synovial, but not skin, fibroblasts could recruit neutrophils in a manner that was dependent on the number of fibroblasts. Antibody blockade of P-selectin or E-selectin reduced neutrophil adhesion, and an antibody against CD18 (the β2 integrin) abolished adhesion. Blockade of CXCR2, but not CXCR1, also greatly inhibited neutrophil recruitment. Interleukin-6 (IL-6) was detectable in coculture supernatants, and both IL-6 and neutrophil adhesion were reduced in a dose-dependent manner by hydrocortisone added to cocultures. Antibody blockade of IL-6 also effectively abolished neutrophil adhesion. CONCLUSION: Synovial fibroblasts from the rheumatoid joint play an important role in regulating the recruitment of inflammatory leukocytes during active disease. This process may depend on a previously unsuspected route of IL-6–mediated crosstalk between fibroblasts and endothelial cells

Distinct Roles for the Anterior Cingulate and Dorsolateral Prefrontal Cortices During Conflict Between Abstract Rules

Distinct patterns of activity within the anterior cingulate cortex (ACC) and dorsolateral prefrontal cortex (dlPFC) reported in neuroimaging studies during tasks involving conflict between competing responses have often been cited as evidence for their key contributions to conflict-monitoring and behavioral adaptation, respectively. However, supporting evidence from neuropsychological patients has been scarce and contradictory. We administered a well-studied analog of the Wisconsin Card Sorting Test, designed to elicit conflict between 2 abstract rules, to a cohort of 6 patients with damage to ACC or dlPFC. Patients who had sustained more significant damage to the ACC were not impaired either on a measure of “conflict cost” nor on measures of “conflict-induced behavioral adaptation.” In contrast, damage to dlPFC did not affect the conflict cost measure but abolished the patients’ ability to adapt their behavior following exposure to conflict, compared with controls. This pattern of results complements the findings from nonhuman primates with more circumscribed lesions to ACC or dlPFC on the same task and provides converging evidence that ACC is not necessary for performance when conflict is elicited between 2 abstract rules, whereas dlPFC plays a fundamental role in behavioral adaptation.The UK Medical Research Council

Pulmonary ORMDL3 is critical for induction of Alternaria -induced allergic airways disease

Genome-wide association studies have identified the ORM (yeast)-like protein isoform 3 (ORMDL3) gene locus on human chromosome 17q to be a highly significant risk factor for childhood-onset asthma. Objective We sought to investigate in vivo the functional role of ORMDL3 in disease inception. Methods An Ormdl3-deficient mouse was generated and the role of ORMDL3 in the generation of allergic airways disease to the fungal aeroallergen Alternaria alternata was determined. An adeno-associated viral vector was also used to reconstitute ORMDL3 expression in airway epithelial cells of Ormdl3 knockout mice. Results Ormdl3 knockout mice were found to be protected from developing allergic airways disease and showed a marked decrease in pathophysiology, including lung function and airway eosinophilia induced by Alternaria. Alternaria is a potent inducer of cellular stress and the unfolded protein response, and ORMDL3 was found to play a critical role in driving the activating transcription factor 6–mediated arm of this response through Xbp1 and downstream activation of the endoplasmic reticulum–associated degradation pathway. In addition, ORMDL3 mediated uric acid release, another marker of cellular stress. In the knockout mice, reconstitution of Ormdl3 transcript levels specifically in the bronchial epithelium resulted in reinstatement of susceptibility to fungal allergen–induced allergic airways disease. Conclusions This study demonstrates that ORMDL3, an asthma susceptibility gene identified by genome-wide association studies, contributes to key pathways that promote changes in airway physiology during allergic immune responses

Imbibition in Disordered Media

The physics of liquids in porous media gives rise to many interesting phenomena, including imbibition where a viscous fluid displaces a less viscous one. Here we discuss the theoretical and experimental progress made in recent years in this field. The emphasis is on an interfacial description, akin to the focus of a statistical physics approach. Coarse-grained equations of motion have been recently presented in the literature. These contain terms that take into account the pertinent features of imbibition: non-locality and the quenched noise that arises from the random environment, fluctuations of the fluid flow and capillary forces. The theoretical progress has highlighted the presence of intrinsic length-scales that invalidate scale invariance often assumed to be present in kinetic roughening processes such as that of a two-phase boundary in liquid penetration. Another important fact is that the macroscopic fluid flow, the kinetic roughening properties, and the effective noise in the problem are all coupled. Many possible deviations from simple scaling behaviour exist, and we outline the experimental evidence. Finally, prospects for further work, both theoretical and experimental, are discussed.Comment: Review article, to appear in Advances in Physics, 53 pages LaTe

Thy-1 Attenuates TNF-α-Activated Gene Expression in Mouse Embryonic Fibroblasts via Src Family Kinase

Heterogeneous surface expression of Thy-1 in fibroblasts modulates inflammation and may thereby modulate injury and repair. As a paradigm, patients with idiopathic pulmonary fibrosis, a disease with pathologic features of chronic inflammation, demonstrate an absence of Thy-1 immunoreactivity within areas of fibrotic activity (fibroblast foci) in contrast to the predominant Thy-1 expressing fibroblasts in the normal lung. Likewise, Thy-1 deficient mice display more severe lung fibrosis in response to an inflammatory injury than wildtype littermates. We investigated the role of Thy-1 in the response of fibroblasts to the pro-inflammatory cytokine TNF-α. Our study demonstrates distinct profiles of TNF-α-activated gene expression in Thy-1 positive (Thy-1+) and negative (Thy-1−) subsets of mouse embryonic fibroblasts (MEF). TNF-α induced a robust activation of MMP-9, ICAM-1, and the IL-8 promoter driven reporter in Thy-1− MEFs, in contrast to only a modest increase in Thy-1+ counterparts. Consistently, ectopic expression of Thy-1 in Thy-1− MEFs significantly attenuated TNF-α-activated gene expression. Mechanistically, TNF-α activated Src family kinase (SFK) only in Thy-1− MEFs. Blockade of SFK activation abrogated TNF-α-activated gene expression in Thy-1− MEFs, whereas restoration of SFK activation rescued the TNF-α response in Thy-1+ MEFs. Our findings suggest that Thy-1 down-regulates TNF-α-activated gene expression via interfering with SFK- and NF-κB-mediated transactivation. The current study provides a novel mechanistic insight to the distinct roles of fibroblast Thy-1 subsets in inflammation

Inception of early-life allergen–induced airway hyperresponsiveness is reliant on IL-13+CD4+ T cells

Airway hyperresponsiveness (AHR) is a critical feature of wheezing and asthma in children, but the initiating immune mechanisms remain unconfirmed. We demonstrate that both recombinant interleukin-33 (rIL-33) and allergen [house dust mite (HDM) or Alternaria alternata] exposure from day 3 of life resulted in significantly increased pulmonary IL-13+CD4+ T cells, which were indispensable for the development of AHR. In contrast, adult mice had a predominance of pulmonary LinnegCD45+CD90+IL-13+ type 2 innate lymphoid cells (ILC2s) after administration of rIL-33. HDM exposure of neonatal IL-33 knockout (KO) mice still resulted in AHR. However, neonatal CD4creIL-13 KO mice (lacking IL-13+CD4+ T cells) exposed to allergen from day 3 of life were protected from AHR despite persistent pulmonary eosinophilia, elevated IL-33 levels, and IL-13+ ILCs. Moreover, neonatal mice were protected from AHR when inhaled Acinetobacter lwoffii (an environmental bacterial isolate found in cattle farms, which is known to protect from childhood asthma) was administered concurrent with HDM. A. lwoffii blocked the expansion of pulmonary IL-13+CD4+ T cells, whereas IL-13+ ILCs and IL-33 remained elevated. Administration of A. lwoffii mirrored the findings from the CD4creIL-13 KO mice, providing a translational approach for disease protection in early life. These data demonstrate that IL-13+CD4+ T cells, rather than IL-13+ ILCs or IL-33, are critical for inception of allergic AHR in early life

Team-taught versus individually taught undergraduate education: A qualitative study of student experiences and preferences

Team teaching is becoming more common in undergraduate programmes of study although the relative merits to the more traditional individually taught courses have not been determined for best practice. For this study, 15 final year undergraduate students were interviewed to gain insight into their learning experiences. A thematic analysis of the interview data identified the perceived advantages and disadvantages of each mode of teaching. The advantages of individually taught courses included: Consistency of content delivery and advice, Familiarity with the lecturer’s teaching style and better Continuity of the subject content. The disadvantage of individually taught modules included Missing knowledge, compared to a team approach. Advantages of team taught modules included: Greater insight into a topic delivered by multiple team members. Disadvantages included: Content overlap, Conflicting messages relating to assessment, team members not taking Ownership of their roles and responsibilities and a belief that overall Team failure is worse than individual failure to deliver a module well. The results revealed that individually taught modules were generally preferred to team taught modules. A set of best practice recommendations are proposed to address the challenges when delivering team-taught teaching and become more student focused

Towards Quantum Repeaters with Solid-State Qubits: Spin-Photon Entanglement Generation using Self-Assembled Quantum Dots

In this chapter we review the use of spins in optically-active InAs quantum dots as the key physical building block for constructing a quantum repeater, with a particular focus on recent results demonstrating entanglement between a quantum memory (electron spin qubit) and a flying qubit (polarization- or frequency-encoded photonic qubit). This is a first step towards demonstrating entanglement between distant quantum memories (realized with quantum dots), which in turn is a milestone in the roadmap for building a functional quantum repeater. We also place this experimental work in context by providing an overview of quantum repeaters, their potential uses, and the challenges in implementing them.Comment: 51 pages. Expanded version of a chapter to appear in "Engineering the Atom-Photon Interaction" (Springer-Verlag, 2015; eds. A. Predojevic and M. W. Mitchell