Niculita-Hirzel, Hélène

Roger, Thierry

Vacher, Gaëlle

Serveur académique lausannois

3rd INTERNATIONAL CONGRESS ON ENVIRONMENTAL HEALTH 2014PORTO, 24th to 26th SEPTEMBER 2014PROCEEDINGSBOOKEMERGING RISKS AND CHALLENGES ON ENVIRONMENT,HEALTH AND SAFETYAllied Health Sciences School of Polytechnic Institute of Porto,Portugal41  HUMAN HEALTH RISK AND PREVENTION  ABSTRACTS Health risks following wheat dust exposure during agricultural work – Focus on Fusarium spp  Authors:  Gaëlle Vacher1, Hélène Niculita-Hirzel1, Thierry Roger2  1 Institute for Work and Health, University of Lausanne and Geneva, Epalinges-Lausanne, Switzerland  2 Infectious Diseases Service, CHUV and University of Lausanne, Lausanne, Switzerland  Presenting Author:  Email: gaelle.vacher@chuv.ch  |  Tel.: +41 213 144 774 |  Fax: +41 213 147 430   INTRODUCTION:  Although inflammatory and innate responses are essential for protective immunity against infection, persistent inflammation in the lungs promotes respiratory diseases. Chronic exposure to high concentration of organic dust can promote such respiratory pathologies. One of the most concerned occupational populations is that of agricultural workers, in particular grain workers who are highly exposed to organic dust during their activities. This population is known to develop complex respiratory diseases due to exposure to grain dust, a complex mixture of fungal particles, bacteria, insect compounds, animal wastes, inorganic compounds(silicates), chemicals, gases and fumes (Linaker & Smedley, 2002).The grain dust components responsible of these pathologies are still unknown. However, Fusarium spp., particularly Fusariumculmorum is one of the most predominant fungal species present in grain dust. Fusarium spp. are responsible for infectious, allergic and toxic effects in humans. Yet, the innate immune response to these species is poorly characterized.   Innate immune cells such as alveolar macrophages lining the respiratory tract and dendritic cells (DCs) located within the epithelium and interstitium of the lung, form the primary line of defense against invading microorganisms. These cells sense microorganisms via pattern recognition receptors (PRRs), which are specialized in the recognition of conserved microbial structures called microbial associated molecular patterns (MAMPs). Upon microbial sensing, innate immune cells produce a panel of cytokines and chemokines that play a key role in the initiation, amplification and regulation of the inflammatory and innate and adaptive immune responses.   OBJECTIVES: Our objective is to characterize the response of innate immune cells to Fusariumculmorum and to identify the PRRS involved in host-fungus interaction.  MATERIALS AND METHODS:  Fusariumculmorum 2156 (thereafter called Fc2156) was isolated by Agroscope from Swiss wheat samples and characterised in our lab.Fc2156 was grown on potato dextrose agar plates. Spores were collected and stored for 18 hours in PBS at 4°C or 22°C before usage. Fc2156was used as total preparation or centrifuged to isolate spores and supernatant. Bone marrow precursors were cultured for 7 days with granulocyte-macrophage colony-stimulating factor (GM-CSF) to obtain bone marrow-derived dendritic cells(BMDC). BMDCs (2.5.106cells/ml in96-well plates) were exposed for 24 hours to lipopolysaccharide (LPS, 10 ng/ml) as control andFc2156preparations (total preparation, spores and supernatant) at an equivalent multiplicity of infection (MOI, i.e. a cell/spore ratio) of 0.01, 0.1 and 1. The concentrations of tumor necrosis factor (TNF), interleukin (IL)-6, IL-12p40, macrophage inflammatory protein (MIP)-1α and MIP-1βin cell culture supernatants were quantified by Luminex.  RESULTS AND DISCUSSION:  Total preparation and spores, but not supernatant, of Fc2156 induced vigorous production of TNF, IL-12p40, MIP-1α, MIP-1β and, to a lesser extent, IL-6 (Table 1 and data not shown). The stimulatory effect followed a bell-shaped response curve, with the highest concentrations of cytokines and chemokines obtained using ABSTRACTS  HUMAN HEALTH RISK AND PREVENTION    42          Fc2156at MOI 0.1. The lowest concentrations of mediators were measured using Fc2156 at MOI 1, due to cytotoxic effects.The differential effects of Fc2156 preparations were also observed using primary macrophages (data not shown).  Table 1 - Cytokine and chemokine release (in pg/ml) by BMDCsexposed to Fusarium spores  TNF IL-6 IL-12p40 MIP-1α MIP-1β Medium 7 3 19 4 23 LPS 10 ng/ml 52 200 975 323 910 F.c 2156MOI 0.01 1188 81 857 946 3115 F.c2156 MOI 0.1 5026 206 1478 7105 6594 F.c2156 MOI 1 213 10 323 770 976   CONCLUSION:  F. culmorum spores strongly activate innate immune cells causing them to release cytokines and chemokines. It is well known that Fusarium spp. produce toxic secondary metabolites such as mycotoxins when exposed to stress conditions. This may account for the observed cytotoxicity and reduced production of inflammatory mediators (Stockmann-Juvala, Alenius, & Savolainen, 2008)when using high loads of F. culmorum. Work is in progress to identify the PRRs implicated in the sensing of F. culmorum spores.  ACKNOWLEDGMENTS:  This work has been financially supported by the ANSES (AgenceNationale de Sécurité Sanitaire de l’Alimentation, de l’Environnement et du Travail, France) grant 2011/1/087, the Faculty of Biology and Medicine Research Commission Fund, University of Lausanne, and the Swiss National Science Foundation (320030_149511).  REFERENCES:  1. Linaker, C., & Smedley, J. (2002). Respiratory illness in agricultural workers. [Review]. Occupational medicine, 52(8), 451-459. 2. Stockmann-Juvala, H., Alenius, H., & Savolainen, K. (2008). Effects of fumonisin B(1) on the expression of cytokines and chemokines in human dendritic cells. [In Vitro Research Support, Non-U.S. Gov't]. Food and chemical toxicology : an international journal published for the British Industrial Biological Research Association, 46(5), 1444-1451.                    

Health risks following wheat dust exposure during agricultural work : focus on Fusarium spp

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Health risks following wheat dust exposure during agricultural work : focus on Fusarium spp

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