Ross P. Walton

Bio: Ross P. Walton is an academic researcher from National Institutes of Health. The author has contributed to research in topics: Rhinovirus & Asthma. The author has an hindex of 23, co-authored 36 publications receiving 2390 citations. Previous affiliations of Ross P. Walton include Medical Research Council & Imperial College London.

IL-33–Dependent Type 2 Inflammation during Rhinovirus-induced Asthma Exacerbations In Vivo

Abstract: Rationale: Rhinoviruses are the major cause of asthma exacerbations; however, its underlying mechanisms are poorly understood. We hypothesized that the epithelial cell–derived cytokine IL-33 plays ...

Mouse models of rhinovirus-induced disease and exacerbation of allergic airway inflammation

Abstract: Rhinoviruses cause serious morbidity and mortality as the major etiological agents of asthma exacerbations and the common cold. A major obstacle to understanding disease pathogenesis and to the development of effective therapies has been the lack of a small-animal model for rhinovirus infection. Of the 100 known rhinovirus serotypes, 90% (the major group) use human intercellular adhesion molecule-1 (ICAM-1) as their cellular receptor and do not bind mouse ICAM-1; the remaining 10% (the minor group) use a member of the low-density lipoprotein receptor family and can bind the mouse counterpart. Here we describe three novel mouse models of rhinovirus infection: minor-group rhinovirus infection of BALB/c mice, major-group rhinovirus infection of transgenic BALB/c mice expressing a mouse-human ICAM-1 chimera and rhinovirus-induced exacerbation of allergic airway inflammation. These models have features similar to those observed in rhinovirus infection in humans, including augmentation of allergic airway inflammation, and will be useful in the development of future therapies for colds and asthma exacerbations.

Co-ordinated Role of TLR3, RIG-I and MDA5 in the Innate Response to Rhinovirus in Bronchial Epithelium

Abstract: The relative roles of the endosomal TLR3/7/8 versus the intracellular RNA helicases RIG-I and MDA5 in viral infection is much debated. We investigated the roles of each pattern recognition receptor in rhinovirus infection using primary bronchial epithelial cells. TLR3 was constitutively expressed; however, RIG-I and MDA5 were inducible by 8–12 h following rhinovirus infection. Bronchial epithelial tissue from normal volunteers challenged with rhinovirus in vivo exhibited low levels of RIG-I and MDA5 that were increased at day 4 post infection. Inhibition of TLR3, RIG-I and MDA5 by siRNA reduced innate cytokine mRNA, and increased rhinovirus replication. Inhibition of TLR3 and TRIF using siRNA reduced rhinovirus induced RNA helicases. Furthermore, IFNAR1 deficient mice exhibited RIG-I and MDA5 induction early during RV1B infection in an interferon independent manner. Hence anti-viral defense within bronchial epithelium requires co-ordinated recognition of rhinovirus infection, initially via TLR3/TRIF and later via inducible RNA helicases.

Rhinovirus-induced IL-25 in asthma exacerbation drives type 2 immunity and allergic pulmonary inflammation

Abstract: Rhinoviruses (RVs), which are the most common cause of virally induced asthma exacerbations, account for much of the burden of asthma in terms of morbidity, mortality, and associated cost. Interleukin-25 (IL-25) activates type 2–driven inflammation and is therefore potentially important in virally induced asthma exacerbations. To investigate this, we examined whether RV-induced IL-25 could contribute to asthma exacerbations. RV-infected cultured asthmatic bronchial epithelial cells exhibited a heightened intrinsic capacity for IL-25 expression, which correlated with donor atopic status. In vivo human IL-25 expression was greater in asthmatics at baseline and during experimental RV infection. In addition, in mice, RV infection induced IL-25 expression and augmented allergen-induced IL-25. Blockade of the IL-25 receptor reduced many RV-induced exacerbation-specific responses including type 2 cytokine expression, mucus production, and recruitment of eosinophils, neutrophils, basophils, and T and non-T type 2 cells. Therefore, asthmatic epithelial cells have an increased intrinsic capacity for expression of a pro–type 2 cytokine in response to a viral infection, and IL-25 is a key mediator of RV-induced exacerbations of pulmonary inflammation.

Respiratory virus induction of alpha-, beta- and lambda-interferons in bronchial epithelial cells and peripheral blood mononuclear cells.

Abstract: Background Respiratory viruses, predominantly rhinoviruses are the major cause of asthma exacerbations. Impaired production of interferon-beta in rhinovirus infected bronchial epithelial cells (BECs) and of the newly discovered interferon-lambdas in both BECs and bronchoalveolar lavage cells, is implicated in asthma exacerbation pathogenesis. Thus replacement of deficient interferon is a candidate new therapy for asthma exacerbations. Rhinoviruses and other respiratory viruses infect both BECs and macrophages, but their relative capacities for alpha-, beta- and lambda-interferon production are unknown. Methods To provide guidance regarding which interferon type is the best candidate for development for treatment/prevention of asthma exacerbations we investigated respiratory virus induction of alpha-, beta- and lambda-interferons in BECs and peripheral blood mononuclear cells (PBMCs) by reverse transferase-polymerase chain reaction and enzyme-linked immunosorbent assay. Results Rhinovirus infection of BEAS-2B BECs induced interferon-alpha mRNA expression transiently at 8 h and interferon-beta later at 24 h while induction of interferon-lambda was strongly induced at both time points. At 24 h, interferon-alpha protein was not detected, interferon-beta was weakly induced while interferon-lambda was strongly induced. Similar patterns of mRNA induction were observed in primary BECs, in response to both rhinovirus and influenza A virus infection, though protein levels were below assay detection limits. In PBMCs interferon-alpha, interferon-beta and interferon-lambda mRNAs were all strongly induced by rhinovirus at both 8 and 24 h and proteins were induced: interferon-alpha>-beta>-lambda. Thus respiratory viruses induced expression of alpha-, beta- and lambda-interferons in BECs and PBMCs. In PBMCs interferon-alpha>-beta>-lambda while in BECs, interferon-lambda>-beta>-alpha. Conclusions We conclude that interferon-lambdas are likely the principal interferons produced during innate responses to respiratory viruses in BECs and interferon-alphas in PBMCs, while interferon-beta is produced by both cell types.

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

Abstract: 抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

The immunology of asthma

Abstract: Asthma is a common disease that affects 300 million people worldwide. Given the large number of eosinophils in the airways of people with mild asthma, and verified by data from murine models, asthma was long considered the hallmark T helper type 2 (T(H)2) disease of the airways. It is now known that some asthmatic inflammation is neutrophilic, controlled by the T(H)17 subset of helper T cells, and that some eosinophilic inflammation is controlled by type 2 innate lymphoid cells (ILC2 cells) acting together with basophils. Here we discuss results from in-depth molecular studies of mouse models in light of the results from the first clinical trials targeting key cytokines in humans and describe the extraordinary heterogeneity of asthma.

Type 2 inflammation in asthma — present in most, absent in many

Abstract: Asthma is one of the most common chronic immunological diseases in humans, affecting people from childhood to old age. Progress in treating asthma has been relatively slow and treatment guidelines have mostly recommended empirical approaches on the basis of clinical measures of disease severity rather than on the basis of the underlying mechanisms of pathogenesis. An important molecular mechanism of asthma is type 2 inflammation, which occurs in many but not all patients. In this Opinion article, I explore the role of type 2 inflammation in asthma, including lessons learnt from clinical trials of inhibitors of type 2 inflammation. I consider how dichotomizing asthma according to levels of type 2 inflammation--into 'T helper 2 (TH2)-high' and 'TH2-low' subtypes (endotypes)--has shaped our thinking about the pathobiology of asthma and has generated new interest in understanding the mechanisms of disease that are independent of type 2 inflammation.

Caspase-1-induced pyroptosis is an innate immune effector mechanism against intracellular bacteria (111.33)

Abstract: Macrophages mediate crucial innate immune responses via caspase-1-dependent processing and secretion of IL-1β and IL-18. While wild type Salmonella typhimurium infection is lethal to mice, a strain that persistently expresses flagellin was cleared by the cytosolic flagellin detection pathway via NLRC4 activation of caspase-1; however, this clearance was independent of IL-1β and IL-18. Instead, caspase-1 induced pyroptotic cell death released bacteria from macrophages, exposing them to uptake and killing by reactive oxygen species in neutrophils. Similarly, caspase-1 cleared Legionella and Burkholderia by cytokine independent mechanisms. Our results show, for the first time, that caspase-1 can clear intracellular bacteria in vivo independent of IL-1β and IL-18, and establish pyroptosis as an efficient mechanism of bacterial clearance by the innate immune system.