CFTR regulates B cell activation and lymphoid follicle development

The number of LFs, BAFF+, TLR4+ and proliferation marker Ki67+ B cells in lung explants or resections from subjects with CF and normal controls was quantified by immunostaining. The role of CFTR in B cell activation and LF development was then examined in two independent cohorts of uninfected CFTR-deficient mice (Cftr -/-) and wild type controls. The number of lung LFs, B cells and BAFF+, CXCR4+, immunoglobulin G+ B cells was examined by immunostaining. Lung and splenocyte B cell activation marker and major histocompatibility complex class II (MHC class II) expression was quantified by flow cytometry. Inflammatory cytokine levels were measured in supernatants from isolated B cells from Cftr -/- and wild type mice stimulated in vitro with Pseudomonas aeruginosa lipopolysaccharide (LPS).CT/MA Cystic Fibrosis/Multiple Sclerosis Fund; May Family Trust; CF Foundation [DRUMMR0, DRUMMR1]Open access journalThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

Fusarium: more than a node or a foot-shaped basal cell

Recent publications have argued that there are potentially serious consequences for researchers in recognising distinct genera in the terminal fusarioid clade of the family Nectriaceae. Thus, an alternate hypothesis, namely a very broad concept of the genus Fusarium was proposed. In doing so, however, a significant body of data that supports distinct genera in Nectriaceae based on morphology, biology, and phylogeny is disregarded. A DNA phylogeny based on 19 orthologous protein-coding genes was presented to support a very broad concept of Fusarium at the F1 node in Nectriaceae. Here, we demonstrate that re-analyses of this dataset show that all 19 genes support the F3 node that represents Fusarium sensu stricto as defined by F. sambucinum (sexual morph synonym Gibberella pulicaris). The backbone of the phylogeny is resolved by the concatenated alignment, but only six of the 19 genes fully support the F1 node, representing the broad circumscription of Fusarium. Furthermore, a re-analysis of the concatenated dataset revealed alternate topologies in different phylogenetic algorithms, highlighting the deep divergence and unresolved placement of various Nectriaceae lineages proposed as members of Fusarium. Species of Fusarium s. str. are characterised by Gibberella sexual morphs, asexual morphs with thin- or thick-walled macroconidia that have variously shaped apical and basal cells, and trichothecene mycotoxin production, which separates them from other fusarioid genera. Here we show that the Wollenweber concept of Fusarium presently accounts for 20 segregate genera with clear-cut synapomorphic traits, and that fusarioid macroconidia represent a character that has been gained or lost multiple times throughout Nectriaceae. Thus, the very broad circumscription of Fusarium is blurry and without apparent synapomorphies, and does not include all genera with fusarium-like macroconidia, which are spread throughout Nectriaceae (e.g., Cosmosporella, Macroconia, Microcera). In this study four new genera are introduced, along with 18 new species and 16 new combinations. These names convey information about relationships, morphology, and ecological preference that would otherwise be lost in a broader definition of Fusarium. To assist users to correctly identify fusarioid genera and species, we introduce a new online identification database, Fusarioid-ID, accessible at www.fusarium.org. The database comprises partial sequences from multiple genes commonly used to identify fusarioid taxa (act1, CaM, his3, rpb1, rpb2, tef1, tub2, ITS, and LSU). In this paper, we also present a nomenclator of names that have been introduced in Fusarium up to January 2021 as well as their current status, types, and diagnostic DNA barcode data. In this study, researchers from 46 countries, representing taxonomists, plant pathologists, medical mycologists, quarantine officials, regulatory agencies, and students, strongly support the application and use of a more precisely delimited Fusarium (= Gibberella) concept to accommodate taxa from the robust monophyletic node F3 on the basis of a well-defined and unique combination of morphological and biochemical features. This F3 node includes, among others, species of the F. fujikuroi, F. incarnatum-equiseti, F. oxysporum, and F. sambucinum species complexes, but not species of Bisifusarium [F. dimerum species complex (SC)], Cyanonectria (F. buxicola SC), Geejayessia (F. staphyleae SC), Neocosmospora (F. solani SC) or Rectifusarium (F. ventricosum SC). The present study represents the first step to generating a new online monograph of Fusarium and allied fusarioid genera (www.fusarium.org)

FcγRIII Is Protective against Pseudomonas aeruginosa Pneumonia

Defenses against bacterial infections involve activation of multiple systems of innate immunity, including complement, Toll-like receptors, and defensins. Reactions to chronic infections bring adaptive immune mechanisms into play as well, with the introduction of modulatory interactions between the two. In humans with chronic lung infections, the severity of inflammation and disease correlate with elevated levels of pathogen-specific immune complexes and complement activation. In mice with genetic deficiency in C5, or targeted deletion of the C5a receptor, Pseudomonas lung infections reveal a role for the C5a anaphylatoxin in disease severity. Deficient animals exhibit significantly reduced survival and clearance of infecting bacteria, simultaneous with greatly increased pulmonary influx of inflammatory cells. Among the actions of C5a on inflammatory cells mediated through the C5a receptor is a shift in the relative expression of Fcγ receptors to increase FcγRIII relative to FcγRII. This shift may significantly impact defenses against chronic infection, reflecting the cellular activation profiles of these IgG receptors. We addressed the role of FcγRIII in defense against Pseudomonas lung infection, and found that, like C5aR-deficient mice, animals with targeted deletion of FcγRIII are more susceptible to mortality upon infection and exhibit reduced clearance of the pathogen. Pseudomonas infection was associated with an increase in the FcγRIII/FcγRII ratio in wild-type mice, and the data support its role as an additional mechanism of host defense against bacterial infection

Specific Interactions of Chemoattractant Factor Receptors with G-proteins

Stimulation of leukocytes with chemoattractant ligands activates phospholipid turnover and calcium release, ultimately leading to chemotaxis, degranulation, and the inflammatory response. The leukocyte response to these ligands is transduced by the interaction of transmembrane receptors with GTP-binding regulatory proteins (G-proteins). To examine the mechanisms of signal transduction by these receptors, we transfected cDNA clones encoding the receptors for the active cleavage product of the fifth component of complement (C5a) and platelet-activating factor (PAF) into COS-7 cells, then measured the production of inositol phosphates (IP) in response to stimulation with these chemoattractant ligands. Cells transfected with the C5a receptor showed no increase in IP production when stimulated with ligand (5-120 nM). However, in cells co-transfected with these receptors and with the cDNA for Gα_(16), a G-protein α subunit that is specific to cells of hematopoietic lineage, addition of ligand caused up to a 5-fold increase in IP production. This interaction was specific, as co-transfection of receptors with the G-proteins Gα_q or Gα_(11) did not allow ligand-dependent increase in IP production. In contrast, ligand-dependent activation of IP production was seen in COS cells transfected solely with the PAF receptor. These results indicate that the C5a receptor utilizes signaling pathways distinct from the PAF receptor and suggest that a pertussis toxin-resistant G-protein, Gα_(16), may play a role in the leukocyte response to inflammatory ligands