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Absence of respiratory burst in X-linked chronic granulomatous disease mice leads to abnormalities in both host defense and inflammatory response to Aspergillus fumigatus.

Morgenstern DE, Gifford MA, Li LL, Doerschuk CM, Dinauer MC - J. Exp. Med. (1997)

Bottom Line: This opportunistic fungal pathogen causes infection in CGD patients due to the deficient generation of neutrophil respiratory burst oxidants important for damaging A. fumigatus hyphae.Alveolar macrophages from X-CGD mice were found to kill A. fumigatus conidia in vitro as effectively as alveolar macrophages from wild-type mice.This is the first experimental evidence that chronic inflammation in CGD does not always result from persistent infection, and suggests that the clinical manifestations of this disorder reflect both impaired microbial killing as well as other abnormalities in the inflammatory response in the absence of a respiratory burst.

View Article: PubMed Central - PubMed

Affiliation: Department of Pediatrics (Hematology-Oncology), Indiana University Medical Center, Indianapolis 46202, USA.

ABSTRACT
Mice with X-linked chronic granulomatous disease (CGD) generated by targeted disruption of the gp91phox subunit of the NADPH-oxidase complex (X-CGD mice) were examined for their response to respiratory challenge with Aspergillus fumigatus. This opportunistic fungal pathogen causes infection in CGD patients due to the deficient generation of neutrophil respiratory burst oxidants important for damaging A. fumigatus hyphae. Alveolar macrophages from X-CGD mice were found to kill A. fumigatus conidia in vitro as effectively as alveolar macrophages from wild-type mice. Pulmonary disease in X-CGD mice was observed after administration of doses ranging from 10(5) to 48 spores, none of which produced disease in wild-type mice. Higher doses produced a rapidly fatal bronchopneumonia in X-CGD mice, whereas progression of disease was slower at lower doses, with development of chronic inflammatory lesions. Marked differences were also observed in the response of X-CGD mice to the administration of sterilized Aspergillus hyphae into the lung. Within 24 hours of administration, X-CGD mice had significantly higher numbers of alveolar neutrophils and increased expression of the proinflammatory cytokines IL-1 beta and TNF-alpha relative to the responses seen in wild-type mice. By one week after administration, pulmonary inflammation was resolving in wild-type mice, whereas X-CGD mice developed chronic granulomatous lesions that persisted for at least six weeks. This is the first experimental evidence that chronic inflammation in CGD does not always result from persistent infection, and suggests that the clinical manifestations of this disorder reflect both impaired microbial killing as well as other abnormalities in the inflammatory response in the absence of a respiratory burst.

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Densitometric analysis of cytokine expression in wild-type  and X-CGD mice receiving A. fumigatus hyphae. Autoradiographs were  scanned and optical density calculated after background subtraction. Optical density was expressed as arbitrary density units and then normalized to  β-actin expression. Data expressed as mean ± SD. (a) IL1β; (b) TNF-α;  (c) KC; (d) TGFβ1. Open bars, wild-type mice; filled bars, X-CGD mice. *,  significantly different from wild type (P <0.05, Mann-Whitney U test);  ‡, significantly different from wild type (P <0.05, t test); §, significantly  different from wild type (P <0.0005, t test); ∥, significantly different from  wild type (P <0.005, t test).
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Figure 7: Densitometric analysis of cytokine expression in wild-type and X-CGD mice receiving A. fumigatus hyphae. Autoradiographs were scanned and optical density calculated after background subtraction. Optical density was expressed as arbitrary density units and then normalized to β-actin expression. Data expressed as mean ± SD. (a) IL1β; (b) TNF-α; (c) KC; (d) TGFβ1. Open bars, wild-type mice; filled bars, X-CGD mice. *, significantly different from wild type (P <0.05, Mann-Whitney U test); ‡, significantly different from wild type (P <0.05, t test); §, significantly different from wild type (P <0.0005, t test); ∥, significantly different from wild type (P <0.005, t test).

Mentions: Of the cytokines examined, IL-1β, TNF-α, JE, and KC showed very low, if any, levels of expression in untreated mice, with no significant differences observed between X-CGD and wild-type mice (Figs. 6 and 7). TGFβ1 expression was detectable in untreated mice at similar levels in wild type and X-CGD (Figs. 6 and 7). The most striking differences in mRNA expression after instillation of hyphae were observed with the proinflammatory cytokines IL-1β and TNF-α. Although markedly increased in both X-CGD and wild-type mice by 24 h after instillation, the expression of IL-1β and TNF-α in X-CGD mice was nearly 5- and 8.5-fold, respectively, higher than levels seen in wild-type animals (Fig. 7, a and b). By 72 h, expression of both cytokine mRNAs had dropped nearly to baseline levels in wild-type mice, while expression in X-CGD mice was even higher than at 24 h and remained persistently elevated for at least a week (Fig. 7, a and b). In addition, we also examined expression of two chemokines, KC and JE. KC, the murine groα homologue, binds to the murine orphan IL-8 receptor and is a potent neutrophil chemoattractant and activator (23), while JE, the murine homologue of monocyte chemoattractant protein-1 has similar activity for monocytes (24). Expression of KC and JE peaked at 24 h in both wild-type and X-CGD mice, and then declined (Fig. 6). Expression of both KC (Fig. 7 c) and JE (data not shown) were significantly higher at 24 h in X-CGD mice relative to wild-type controls, and KC remained significantly elevated in X-CGD versus wild-type mice at 72 h and 1 wk (three- to fivefold, respectively). TGFβ1 was significantly elevated in X-CGD mice relative to wild-type controls at 24 h, but not at later time points (Fig. 7 d).


Absence of respiratory burst in X-linked chronic granulomatous disease mice leads to abnormalities in both host defense and inflammatory response to Aspergillus fumigatus.

Morgenstern DE, Gifford MA, Li LL, Doerschuk CM, Dinauer MC - J. Exp. Med. (1997)

Densitometric analysis of cytokine expression in wild-type  and X-CGD mice receiving A. fumigatus hyphae. Autoradiographs were  scanned and optical density calculated after background subtraction. Optical density was expressed as arbitrary density units and then normalized to  β-actin expression. Data expressed as mean ± SD. (a) IL1β; (b) TNF-α;  (c) KC; (d) TGFβ1. Open bars, wild-type mice; filled bars, X-CGD mice. *,  significantly different from wild type (P <0.05, Mann-Whitney U test);  ‡, significantly different from wild type (P <0.05, t test); §, significantly  different from wild type (P <0.0005, t test); ∥, significantly different from  wild type (P <0.005, t test).
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Figure 7: Densitometric analysis of cytokine expression in wild-type and X-CGD mice receiving A. fumigatus hyphae. Autoradiographs were scanned and optical density calculated after background subtraction. Optical density was expressed as arbitrary density units and then normalized to β-actin expression. Data expressed as mean ± SD. (a) IL1β; (b) TNF-α; (c) KC; (d) TGFβ1. Open bars, wild-type mice; filled bars, X-CGD mice. *, significantly different from wild type (P <0.05, Mann-Whitney U test); ‡, significantly different from wild type (P <0.05, t test); §, significantly different from wild type (P <0.0005, t test); ∥, significantly different from wild type (P <0.005, t test).
Mentions: Of the cytokines examined, IL-1β, TNF-α, JE, and KC showed very low, if any, levels of expression in untreated mice, with no significant differences observed between X-CGD and wild-type mice (Figs. 6 and 7). TGFβ1 expression was detectable in untreated mice at similar levels in wild type and X-CGD (Figs. 6 and 7). The most striking differences in mRNA expression after instillation of hyphae were observed with the proinflammatory cytokines IL-1β and TNF-α. Although markedly increased in both X-CGD and wild-type mice by 24 h after instillation, the expression of IL-1β and TNF-α in X-CGD mice was nearly 5- and 8.5-fold, respectively, higher than levels seen in wild-type animals (Fig. 7, a and b). By 72 h, expression of both cytokine mRNAs had dropped nearly to baseline levels in wild-type mice, while expression in X-CGD mice was even higher than at 24 h and remained persistently elevated for at least a week (Fig. 7, a and b). In addition, we also examined expression of two chemokines, KC and JE. KC, the murine groα homologue, binds to the murine orphan IL-8 receptor and is a potent neutrophil chemoattractant and activator (23), while JE, the murine homologue of monocyte chemoattractant protein-1 has similar activity for monocytes (24). Expression of KC and JE peaked at 24 h in both wild-type and X-CGD mice, and then declined (Fig. 6). Expression of both KC (Fig. 7 c) and JE (data not shown) were significantly higher at 24 h in X-CGD mice relative to wild-type controls, and KC remained significantly elevated in X-CGD versus wild-type mice at 72 h and 1 wk (three- to fivefold, respectively). TGFβ1 was significantly elevated in X-CGD mice relative to wild-type controls at 24 h, but not at later time points (Fig. 7 d).

Bottom Line: This opportunistic fungal pathogen causes infection in CGD patients due to the deficient generation of neutrophil respiratory burst oxidants important for damaging A. fumigatus hyphae.Alveolar macrophages from X-CGD mice were found to kill A. fumigatus conidia in vitro as effectively as alveolar macrophages from wild-type mice.This is the first experimental evidence that chronic inflammation in CGD does not always result from persistent infection, and suggests that the clinical manifestations of this disorder reflect both impaired microbial killing as well as other abnormalities in the inflammatory response in the absence of a respiratory burst.

View Article: PubMed Central - PubMed

Affiliation: Department of Pediatrics (Hematology-Oncology), Indiana University Medical Center, Indianapolis 46202, USA.

ABSTRACT
Mice with X-linked chronic granulomatous disease (CGD) generated by targeted disruption of the gp91phox subunit of the NADPH-oxidase complex (X-CGD mice) were examined for their response to respiratory challenge with Aspergillus fumigatus. This opportunistic fungal pathogen causes infection in CGD patients due to the deficient generation of neutrophil respiratory burst oxidants important for damaging A. fumigatus hyphae. Alveolar macrophages from X-CGD mice were found to kill A. fumigatus conidia in vitro as effectively as alveolar macrophages from wild-type mice. Pulmonary disease in X-CGD mice was observed after administration of doses ranging from 10(5) to 48 spores, none of which produced disease in wild-type mice. Higher doses produced a rapidly fatal bronchopneumonia in X-CGD mice, whereas progression of disease was slower at lower doses, with development of chronic inflammatory lesions. Marked differences were also observed in the response of X-CGD mice to the administration of sterilized Aspergillus hyphae into the lung. Within 24 hours of administration, X-CGD mice had significantly higher numbers of alveolar neutrophils and increased expression of the proinflammatory cytokines IL-1 beta and TNF-alpha relative to the responses seen in wild-type mice. By one week after administration, pulmonary inflammation was resolving in wild-type mice, whereas X-CGD mice developed chronic granulomatous lesions that persisted for at least six weeks. This is the first experimental evidence that chronic inflammation in CGD does not always result from persistent infection, and suggests that the clinical manifestations of this disorder reflect both impaired microbial killing as well as other abnormalities in the inflammatory response in the absence of a respiratory burst.

Show MeSH
Related in: MedlinePlus