Re: Rand & Miller~Inflammation From Fungi~Toxins

More | Report Post

Do you have mouse lungs? If not, this is not applicable to
humans.

On 12/23/09, Sharon wrote:
> Arch Toxicol. 2009 Nov 11. [Epub ahead of print]
>
>
>
> Dectin-1 and inflammation-associated gene transcription and
> expression in mouse lungs by a toxic (1,3)-beta-D: glucan.
>
> Rand TG, Sun M, Gilyan A, Downey J, Miller JD.
>
>
>
> Department of Biology, Saint Mary's University, 923 Robie
> St., Halifax, NS, B3H 3C3, Canada, thomas.rand@smu.ca.
>
>
>
> The form of (1-3)-beta-D: glucan found in the cell walls of
> the anamorphic Trichocomaceae that grow on damp building
> materials is considered to have potent toxic and
> inflammatory effects on cells of the respiratory system. It
> is also considered to have a potential role in the
> development of non-allergenic respiratory health effects.
> While human studies involving experimental exposures all
> point to the inflammatory potential of pure curdlan, a
> linear (1-3)-beta-D: glucan in a triple helix
> configuration, animal experiments result in conflicting
> conclusions concerning the inflammatory potency of this
> glucan. However, because mice appear to be a better model
> than guinea pigs for exploring the respiratory effects of
> curdlan and because molecular mechanisms associated with
> this glucan remain largely unknown, we conducted further
> work to clarify the role of curdlan on the inflammatory
> response using our mouse model of lung disease. This study
> used in situ hybridization (ISH) to probe dectin-1 mRNA
> transcription with a digoxigenin-labeled cDNA probe, with
> reverse transcription (RT)-PCR based arrays used to measure
> inflammation gene and receptor transcriptional responses.
> Also, immunohistochemistry (IHC) was used to probe dectin-1
> as well as anti-mouse Ccl3, Il1-alpha, and TNF-alpha
> expression to evaluate dose and time-course (4 and 12 h)
> postexposure (PE) response patterns in the lungs of
> intratracheally instilled mice exposed to a single 50 mul
> dose of curdlan at 10(-7), 10(-8), 10(-9), and 10(-10)
> M/animal (=4 mug to 4 ng curdlan/kg lung wt). Dectin-1 mRNA
> transcription and expression was observed in bronchiolar
> epithelium, alveolar macrophages (AMs), and alveolar type
> II cells (ATIIs) of lungs exposed to 4 mug to 40 ng
> curdlan/kg lung wt, at both time points. Compared to
> controls, array analysis revealed that 54 of 83 genes
> assayed were significantly modulated by curdlan. mRNA
> transcription patterns showed both dose and time
> dependency, with highest transcription levels in 10(-7) and
> 10(-8) M treatment animals, especially at 4-h PE. Nine gene
> mRNA transcripts (Ccl3, Ccl11, Ccl17, Ifng, Il1alpha, Il-
> 20, TNF-alpha, Tnfrsf1b, and CD40lg) were significantly
> expressed at all doses suggesting they may have a central
> role in immunomodulating curdlan exposures. IHC revealed
> Ccl3, Il1-alpha, and TNF-alpha expression in bronchiolar
> epithelium, AMs and ATIIs illustrate the important
> immunomodulatory role that these cells have in the
> recognition of, and response to glucan. Collectively, these
> results confirm the inflammatory nature of curdlan and
> demonstrate the complex of inflammation-associated gene
> responses induced by (1-3)-beta-D: glucan in triple helical
> forms. These observations also provide a biological basis
> for the irritant and inflammatory response to curdlan
> observed in humans and animals in experimental studies.
>
>
>
>
>
> Chem Biol Interact. 2010 Jan 5;183(1):113-24.
>
>
>
> Inflammation-associated gene transcription and expression
> in mouse lungs induced by low molecular weight compounds
> from fungi from the built environment.
>
> Miller JD, Sun M, Gilyan A, Roy J, Rand TG.
>
>
>
> Department of Chemistry, Carleton University, Ottawa,
> Ontario, Canada K1S 5B6.
>
>
>
> Few metabolites from fungi found indoors have been tested
> for inflammatory mediators endpoints in primary cultures of
> alveolar macrophages or in vivo. In this study, mice were
> intratracheally instilled with a single dose comprising 4x10
> (-5)moletoxin/kg lung wt dose of either atranone C,
> brevianamide, cladosporin, mycophenolic acid, neoechinulin
> A & B, sterigmatocystin or TMC-120A. These toxins are from
> fungi common on damp building materials. The dose used was
> comparable to the estimated doses of possible human
> exposure. Hematoxylin and eosin (H&E) histology and Alcian
> Blue/Periodic Acid Schiff (AB/PAS) histochemistry were used
> to evaluate lungs for time course (4h and 12h post-exposure
> (PE)) inflammatory and toxic changes. Reverse-transcription
> (RT)-PCR based arrays were also employed to evaluate time
> course inflammation-associated gene transcription in lung
> tissues of the different toxins. Immunohistochemistry (IHC)
> was used to probe MIP-2 and Tnf-alpha protein expression in
> treatment lungs to determine whether responses correspond
> with gene transcription data. Both histology and
> histochemistry revealed that toxin exposed lungs at 12h PE
> showed evidence of inflammation. H&E revealed that
> bronchioli were lined with irregularly thickened and
> sometimes sloughing epithelium and bronchiolar spaces
> supported infiltration of leukocytes, cellular and mucus-
> like debris while alveolar spaces supported swollen
> macrophages and modest amorphous debris accumulations. All
> toxin-instilled lungs exhibited copious mucus production
> and alveolar macrophages with red stained cytoplasm on
> bronchiolar surfaces, especially at 12h PE. Array analysis
> of 83 inflammation-associated genes extracted from lung
> tissue demonstrated a number of patterns, compared to
> controls. 82 genes assayed at 4h PE and 75 genes at 12h PE
> were significantly altered (p< or =0.05; >or =1.5-fold or <
> or =-1.5-fold change) in the different treatment animal
> groups. Expression of transcriptionally regulated genes was
> confirmed using immunohistochemistry that demonstrated MIP-
> 2 and Tnf-alpha staining in respiratory bronchiolar
> epithelia, alveolar macrophages and alveolar type II cells.
> The transcriptional regulation in these genes in the
> treatment groups suggests that they may serve central roles
> in the immunomodulation of toxin-induced pro-inflammatory
> lung responses. Hierarchical cluster analysis revealed
> significant patterns of gene transcription linking the
> response of the toxins at equimolar doses in three groups:
> (1) brevianamide, mycophenolic acid and neoechinulin B, (2)
> neoechinulin A and sterigmatocystin, and (3) cladosporin,
> atranone C and TMC-120. The results further confirm the
> inflammatory nature of metabolites/toxins from such fungi
> can contribute to the development of non-allergenic
> respiratory health effects