Convergent evolution of water conducting cells in Marchantia recruited the ZHOUPI gene promoting cell wall reinforcement and programmed cell death

A key adaptation of plants to life on land is the formation of water conducting cells (WCC) for efficient long-distance water transport. Based on morphological analyses it is thought that WCC have evolved independently on multiple occasions. For example, WCC have been lost in all but a few lineages of bryophytes but strikingly, within the liverworts a derived group, the complex thalloids, has evolved a novel externalised water conducting tissue composed of reinforced, hollow cells termed pegged rhizoids. Here we show that pegged rhizoid differentiation in Marchantia polymorpha is controlled by orthologues of the ZHOUPI and ICE bHLH transcription factors required for endosperm cell death in Arabidopsis seeds. By contrast, pegged rhizoid development was not affected by disruption of MpNAC5, the Marchantia orthologue of the VND genes that control WCC formation in flowering plants. We characterize the rapid, genetically controlled programmed cell death process that pegged rhizoids undergo to terminate cellular differentiation, and identify a corresponding upregulation of conserved putative plant cell death effector genes. Lastly, we show that ectopic expression of MpZOU1 increases production of pegged rhizoids and enhances drought tolerance. Our results support that pegged rhizoids having evolved independently of other WCC. We suggest that elements of the genetic control of developmental cell death are conserved throughout land plants and that the ZHOUPI/ICE regulatory module has been independently recruited to promote cell wall modification and programmed cell death in liverwort rhizoids and in the endosperm of flowering plant seed

In Situ Microscopy Analysis Reveals Local Innate Immune Response Developed around Brucella Infected Cells in Resistant and Susceptible Mice

Brucella are facultative intracellular bacteria that chronically infect humans and animals causing brucellosis. Brucella are able to invade and replicate in a broad range of cell lines in vitro, however the cells supporting bacterial growth in vivo are largely unknown. In order to identify these, we used a Brucella melitensis strain stably expressing mCherry fluorescent protein to determine the phenotype of infected cells in spleen and liver, two major sites of B. melitensis growth in mice. In both tissues, the majority of primary infected cells expressed the F4/80 myeloid marker. The peak of infection correlated with granuloma development. These structures were mainly composed of CD11b+ F4/80+ MHC-II+ cells expressing iNOS/NOS2 enzyme. A fraction of these cells also expressed CD11c marker and appeared similar to inflammatory dendritic cells (DCs). Analysis of genetically deficient mice revealed that differentiation of iNOS+ inflammatory DC, granuloma formation and control of bacterial growth were deeply affected by the absence of MyD88, IL-12p35 and IFN-γ molecules. During chronic phase of infection in susceptible mice, we identified a particular subset of DC expressing both CD11c and CD205, serving as a reservoir for the bacteria. Taken together, our results describe the cellular nature of immune effectors involved during Brucella infection and reveal a previously unappreciated role for DC subsets, both as effectors and reservoir cells, in the pathogenesis of brucellosis

X-linked primary ciliary dyskinesia due to mutations in the cytoplasmic axonemal dynein assembly factor PIH1D3

By moving essential body fluids and molecules, motile cilia and flagella govern respiratory mucociliary clearance, laterality determination and the transport of gametes and cerebrospinal fluid. Primary ciliary dyskinesia (PCD) is an autosomal recessive disorder frequently caused by non-assembly of dynein arm motors into cilia and flagella axonemes. Before their import into cilia and flagella, multi-subunit axonemal dynein arms are thought to be stabilized and pre-assembled in the cytoplasm through a DNAAF2–DNAAF4–HSP90 complex akin to the HSP90 co-chaperone R2TP complex. Here, we demonstrate that large genomic deletions as well as point mutations involving PIH1D3 are responsible for an X-linked form of PCD causing disruption of early axonemal dynein assembly. We propose that PIH1D3, a protein that emerges as a new player of the cytoplasmic pre-assembly pathway, is part of a complementary conserved R2TP-like HSP90 co-chaperone complex, the loss of which affects assembly of a subset of inner arm dyneins

A multistage controlled intervention to increase stair climbing at work: effectiveness and process evaluation

International audienceBackgroundStair climbing helps to accumulate short bouts of physical activity throughout the day as a strategy for attaining recommended physical activity levels. There exists a need for effective long-term stair-climbing interventions that can be transferred to various worksite settings. The aims of this study were: 1) to evaluate short- and long-term effectiveness of a worksite stair-climbing intervention using an objective measurement of stair climbing and a controlled design; and 2) to perform a process evaluation of the intervention.MethodsWe performed a controlled before-and-after study. The study was conducted in two corporate buildings of the same company located in Paris (France), between September, 2013 and September, 2014. The status of either “intervention site” or “control site” was assigned by the investigators. Participants were on-site employees (intervention site: n = 783; control site: n = 545 at baseline). Two one-month intervention phases using signs (intervention phase 1) and enhancement of stairwell aesthetics (intervention phase 2) were performed. The main outcome was the change in stair climbing, measured with automatic counters and expressed in absolute counts/day/100 employees and percent change compared to baseline. Qualitative outcomes were used to describe the intervention process.ResultsStair climbing significantly increased at the intervention site (+18.7 %) but decreased at the control site (-13.3 %) during the second intervention phase (difference between sites: +4.6 counts/day/100 employees, p < 0.001). After the intervention and over the long term, stair climbing returned to baseline levels at the intervention site, but a significant difference between sites was found (intervention site vs. control site: +2.9 counts/day/100 employees, p < 0.05). Some important facets of the intervention were implemented as intended but other aspects had to be adapted. The main difficulty reported by the company’s staff members lay in matching the internal communications rules with critical intervention criteria. The program was maintained at the setting level after the end of the study.ConclusionsThis study shows a successful stair-climbing intervention at the worksite. The main barriers to adoption and implementation were related to location and visibility of posters. Process evaluation was useful in identifying these barriers throughout the study, and in finding appropriate solutions

FGF10 Signaling differences between type I pleuropulmonary blastoma and congenital cystic adenomatoid malformation.

International audienceBACKGROUND: Type I pleuropulmonary blastoma (PPB) and congenital cystic adenomatoid malformation of the lung (CCAM) are cystic lung diseases of childhood. Their clinical and radiological presentations are often similar, and pathologic discrimination remains difficult in many cases. As a consequence, type I PPB and CCAM are frequently confused, leading to delayed adequate management for type I PPB. Recent studies have suggested a role for fibroblast growth factor (FGF) 10 signal pathway in CCAM pathogenesis. The objective of our study was to determine whether FGF10 signaling differs between CCAM and type I PPB. METHODS: Immunohistochemical studies were performed for expression of FGF10, its receptor FGFR2b, and its inhibitor sonic hedgehog (SHH) in focal type I PPB (n=6), CCAM type I (n=7), CCAM type II (n=7), and control lungs (n=5). RESULTS: FGF10, FGFR2b, and SHH expressions differed markedly between type I PPB and both types of CCAM. Type I and type II CCAM cystic walls expressed FGF10, FGFR2b, and SHH, whereas staining was absent or poor in type I PBB cystic walls. Expression of FGF10, FGFR2b, and SHH did not differ between CCAM cystic walls and control airway walls. CONCLUSIONS: These findings show that immunohistochemistry with FGF10, FGFR2b, or SHH could be useful in differentiating CCAM from type I PPB, when a child presents with a focal cystic lung lesion. The absence of strong expression of FGF10, FGFR2b, and/or SHH makes the diagnosis of CCAM very doubtful

CD11b⁺ granulomas in the spleen and liver of wild type and MyD88-deficient infected mice.

<p>Mice were injected i.p. with PBS (control) or 10⁸ CFU of mCherry-Br. The figure presents the localization by immunohistofluorescence of CD11b^hi and iNOS expressing cells in spleen (<b>A</b>) and liver (<b>B</b>) from control and 120 h mCherry-Br infected wild-type and MyD88^−/− C57BL/6. Panels are color-coded with the text for the antigen or mCherry-Br examined. Scale bar = 200 µm, as indicated. r.p.: red pulp; w.p.: white pulp. Data are representative of at least 3 independent experiments.</p

Phenotypical characterization of <i>B. melitensis</i> infected cells in the spleen.

<p>Wild-type C57BL/6 and BALB/c mice were injected i.p. with PBS or 10⁸ CFU of mCherry-Br. Mice were sacrificed at selected times and spleens were collected and examined by immunohistofluorescence. Data indicate the percentage of mCherry-Br that colocalizes with (<b>A</b>) CD90.2-, B220-, Ly6G-, MOMA-1-, F4/80-, CD11c-, (<b>B</b>) MHCII-, iNOS-, CD11b-expressing cells at the selected time in C57BL/7 mice. (<b>C</b>) Comparison at 120 h p.i. between C57BL/6 and BALB/c mice. The bars are the mean±SD from at least 3 spleen sections per spleen from 5 mice.</p

Phenotypical analysis of granuloma in the liver of wild type and MyD88-deficient infected mice.

<p>Colocalization by immunohistofluorescence of CD11c (<b>A</b>), F4/80 (<b>B</b>), Ly-6G (<b>C</b>) and iNOS expressing cells with mCherry-Br signal in liver from 120 h mCherry-Br infected wild-type and MyD88^−/− C57BL/6. Mice were injected i.p. with 10⁸ CFU of mCherry-Br. Panels are color-coded with the text for the antigen or mCherry-Br examined. Scale bar = 50 µm, as indicated. Data are representative of at least 3 independent experiments.</p

Phenotypical analysis of granuloma in the liver and spleen of wild type and RAG-deficient infected mice.

<p>Localization by immunohistofluorescence of (<b>A</b>) F4/80, (<b>B</b>) CD11b, (<b>C</b>) CD11c and iNOS expressing cells in liver and spleen from 120 h mCherry-Br infected wild-type and RAG^−/− C57BL/6. Mice were injected i.p. with 10⁸ CFU of mCherry-Br. Images represent a single granuloma. Panels are color-coded with the text for the antigen or mCherry-Br examined. Scale bar = 50 µm, as indicated. Data are representative of at least 3 independent experiments.</p