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Gpr97 Is Dispensable for Inflammation in OVA-Induced Asthmatic Mice.

Shi JP, Li XN, Zhang XY, Du B, Jiang WZ, Liu MY, Wang JJ, Wang ZG, Ren H, Qian M - PLoS ONE (2015)

Bottom Line: In our study, no obvious alteration in the inflammatory response or airway remodeling was found in the Gpr97-deficient mice with OVA-induced asthma.Neither the secretion of cytokines, including IL-4, IL-6 and IFN-γ, nor inflammatory cell recruitment was altered in the Gpr97-deficient mice.Our findings imply that Gpr97 might not be required for the development of airway inflammation in OVA-induced allergic asthma in mice.

View Article: PubMed Central - PubMed

Affiliation: Shanghai Key Laboratory of Regulatory Biology, School of Life Sciences, East China Normal University, Shanghai, China; Institute of Biomedical Sciences, School of Life Sciences, East China Normal University, Shanghai, China.

ABSTRACT

Background: Asthma is a complex inflammatory disorder involving the activation and invasion of various immune cells. GPR97 is highly expressed in some immunocytes, including mast cells and eosinophils, which play critical roles in asthma development. However, the role of Gpr97 in regulating airway inflammation in asthma has rarely been reported. In this study, we investigated the potential role of Gpr97 in the development of allergic asthma in mice.

Methods: Relevant airway asthmatic mouse models were constructed with both wild-type and Gpr97-/- mice sensitized to 250 μg ovalbumin (OVA). The levels of interleukin IL-4, IL-6 and IFN-γ, which are involved in OVA-induced asthma, in the bronchoalveolar lavage fluid (BALF) and the IgE level in the serum were examined by enzyme-linked immunosorbent assay (ELISA). The invasion of mast cells and eosinophils into lung tissues was assessed by immunohistochemical and eosinophil peroxidase activity assays, respectively. Goblet cell hyperplasia and mucus production were morphologically evaluated with periodic acid-Schiff (PAS) staining.

Results: In our study, no obvious alteration in the inflammatory response or airway remodeling was found in the Gpr97-deficient mice with OVA-induced asthma. Neither the secretion of cytokines, including IL-4, IL-6 and IFN-γ, nor inflammatory cell recruitment was altered in the Gpr97-deficient mice. Moreover, Gpr97 deficiency did not affect airway remodeling or mucus production in the asthma mouse model.

Conclusion: Our findings imply that Gpr97 might not be required for the development of airway inflammation in OVA-induced allergic asthma in mice.

No MeSH data available.


Related in: MedlinePlus

Airway remodeling of lung tissues in OVA-induced WT and Gpr97-/- asthmatic mice.(A) Lung edema following OVA challenge was determined according to the lung/body weight ratio. (B) Hyperplasia of the goblet cells along with mucus production were measured by PAS staining and examined by light microscopy at 10× magnification. The black square in the upper right corner of each picture shows the positively stained area at a higher magnification of 40×. Scale bars: 100 μm in the panel. (C) The ratios of PAS-positive goblet cells were counted using Image-Pro Plus 6.0 software. The data were normalized to the PBS sample data and are presented as the mean ± SEM (n = 6 animals for each genotype, as indicated by asterisks (** P < 0.01, and *** P < 0.001). (D) Masson’s trichrome staining was used to determinate the subepithelial fibrosis in lung tissues in OVA and saline challenge mice. The black square in the upper right corner of each picture shows the positively stained area at a higher magnification of 40×. In the pictures, cytoplasm is stained in red and collagen in blue.
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pone.0131461.g004: Airway remodeling of lung tissues in OVA-induced WT and Gpr97-/- asthmatic mice.(A) Lung edema following OVA challenge was determined according to the lung/body weight ratio. (B) Hyperplasia of the goblet cells along with mucus production were measured by PAS staining and examined by light microscopy at 10× magnification. The black square in the upper right corner of each picture shows the positively stained area at a higher magnification of 40×. Scale bars: 100 μm in the panel. (C) The ratios of PAS-positive goblet cells were counted using Image-Pro Plus 6.0 software. The data were normalized to the PBS sample data and are presented as the mean ± SEM (n = 6 animals for each genotype, as indicated by asterisks (** P < 0.01, and *** P < 0.001). (D) Masson’s trichrome staining was used to determinate the subepithelial fibrosis in lung tissues in OVA and saline challenge mice. The black square in the upper right corner of each picture shows the positively stained area at a higher magnification of 40×. In the pictures, cytoplasm is stained in red and collagen in blue.

Mentions: Next, we evaluated the effects of Gpr97 on airway structural conformation and mucus hypersecretion in lung tissue, which are two additional characteristics of OVA-induced allergic asthma [24]. Lungs were weighed to analyze airway edema. The lung/body weight ratios were slightly increased in the WT and Gpr97-deficient mice following the OVA challenge compared to the saline challenge. However, no alterations in edema occurred in the OVA-induced Gpr97-/- mice (Fig 4A). In the lung tissues of the mice with allergic asthma, hyperplasia of the goblet cells, which are mostly mucus-producing cells, was observed in our previous experiment. At same time, a similar hyperplasia of the goblet cells was also observed under a light microscope in the OVA-treated Gpr97-deficient mice using the PAS special staining method (Fig 4B). The number of PAS-positive cells was determined by Soft Image-Pro Plus (Version 6.0), and the results showed a greater increase in goblet cells in the airway epithelial layer of the OVA-challenged mice regardless of whether they were Gpr97-deficient (Fig 4C). There was still no difference in goblet cell hyperplasia or mucus hypersecretion between the WT and Gpr97-/- allergic asthma mice. Then the subepithelial fibrosis in lung tissues were determinate using Masson’s trichrome staining. Although the deposition of extracellular matrix was increased with OVA challenge, but no obvious difference was found in Gpr97-deficient asthmatic mice (Fig 4D).


Gpr97 Is Dispensable for Inflammation in OVA-Induced Asthmatic Mice.

Shi JP, Li XN, Zhang XY, Du B, Jiang WZ, Liu MY, Wang JJ, Wang ZG, Ren H, Qian M - PLoS ONE (2015)

Airway remodeling of lung tissues in OVA-induced WT and Gpr97-/- asthmatic mice.(A) Lung edema following OVA challenge was determined according to the lung/body weight ratio. (B) Hyperplasia of the goblet cells along with mucus production were measured by PAS staining and examined by light microscopy at 10× magnification. The black square in the upper right corner of each picture shows the positively stained area at a higher magnification of 40×. Scale bars: 100 μm in the panel. (C) The ratios of PAS-positive goblet cells were counted using Image-Pro Plus 6.0 software. The data were normalized to the PBS sample data and are presented as the mean ± SEM (n = 6 animals for each genotype, as indicated by asterisks (** P < 0.01, and *** P < 0.001). (D) Masson’s trichrome staining was used to determinate the subepithelial fibrosis in lung tissues in OVA and saline challenge mice. The black square in the upper right corner of each picture shows the positively stained area at a higher magnification of 40×. In the pictures, cytoplasm is stained in red and collagen in blue.
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4489018&req=5

pone.0131461.g004: Airway remodeling of lung tissues in OVA-induced WT and Gpr97-/- asthmatic mice.(A) Lung edema following OVA challenge was determined according to the lung/body weight ratio. (B) Hyperplasia of the goblet cells along with mucus production were measured by PAS staining and examined by light microscopy at 10× magnification. The black square in the upper right corner of each picture shows the positively stained area at a higher magnification of 40×. Scale bars: 100 μm in the panel. (C) The ratios of PAS-positive goblet cells were counted using Image-Pro Plus 6.0 software. The data were normalized to the PBS sample data and are presented as the mean ± SEM (n = 6 animals for each genotype, as indicated by asterisks (** P < 0.01, and *** P < 0.001). (D) Masson’s trichrome staining was used to determinate the subepithelial fibrosis in lung tissues in OVA and saline challenge mice. The black square in the upper right corner of each picture shows the positively stained area at a higher magnification of 40×. In the pictures, cytoplasm is stained in red and collagen in blue.
Mentions: Next, we evaluated the effects of Gpr97 on airway structural conformation and mucus hypersecretion in lung tissue, which are two additional characteristics of OVA-induced allergic asthma [24]. Lungs were weighed to analyze airway edema. The lung/body weight ratios were slightly increased in the WT and Gpr97-deficient mice following the OVA challenge compared to the saline challenge. However, no alterations in edema occurred in the OVA-induced Gpr97-/- mice (Fig 4A). In the lung tissues of the mice with allergic asthma, hyperplasia of the goblet cells, which are mostly mucus-producing cells, was observed in our previous experiment. At same time, a similar hyperplasia of the goblet cells was also observed under a light microscope in the OVA-treated Gpr97-deficient mice using the PAS special staining method (Fig 4B). The number of PAS-positive cells was determined by Soft Image-Pro Plus (Version 6.0), and the results showed a greater increase in goblet cells in the airway epithelial layer of the OVA-challenged mice regardless of whether they were Gpr97-deficient (Fig 4C). There was still no difference in goblet cell hyperplasia or mucus hypersecretion between the WT and Gpr97-/- allergic asthma mice. Then the subepithelial fibrosis in lung tissues were determinate using Masson’s trichrome staining. Although the deposition of extracellular matrix was increased with OVA challenge, but no obvious difference was found in Gpr97-deficient asthmatic mice (Fig 4D).

Bottom Line: In our study, no obvious alteration in the inflammatory response or airway remodeling was found in the Gpr97-deficient mice with OVA-induced asthma.Neither the secretion of cytokines, including IL-4, IL-6 and IFN-γ, nor inflammatory cell recruitment was altered in the Gpr97-deficient mice.Our findings imply that Gpr97 might not be required for the development of airway inflammation in OVA-induced allergic asthma in mice.

View Article: PubMed Central - PubMed

Affiliation: Shanghai Key Laboratory of Regulatory Biology, School of Life Sciences, East China Normal University, Shanghai, China; Institute of Biomedical Sciences, School of Life Sciences, East China Normal University, Shanghai, China.

ABSTRACT

Background: Asthma is a complex inflammatory disorder involving the activation and invasion of various immune cells. GPR97 is highly expressed in some immunocytes, including mast cells and eosinophils, which play critical roles in asthma development. However, the role of Gpr97 in regulating airway inflammation in asthma has rarely been reported. In this study, we investigated the potential role of Gpr97 in the development of allergic asthma in mice.

Methods: Relevant airway asthmatic mouse models were constructed with both wild-type and Gpr97-/- mice sensitized to 250 μg ovalbumin (OVA). The levels of interleukin IL-4, IL-6 and IFN-γ, which are involved in OVA-induced asthma, in the bronchoalveolar lavage fluid (BALF) and the IgE level in the serum were examined by enzyme-linked immunosorbent assay (ELISA). The invasion of mast cells and eosinophils into lung tissues was assessed by immunohistochemical and eosinophil peroxidase activity assays, respectively. Goblet cell hyperplasia and mucus production were morphologically evaluated with periodic acid-Schiff (PAS) staining.

Results: In our study, no obvious alteration in the inflammatory response or airway remodeling was found in the Gpr97-deficient mice with OVA-induced asthma. Neither the secretion of cytokines, including IL-4, IL-6 and IFN-γ, nor inflammatory cell recruitment was altered in the Gpr97-deficient mice. Moreover, Gpr97 deficiency did not affect airway remodeling or mucus production in the asthma mouse model.

Conclusion: Our findings imply that Gpr97 might not be required for the development of airway inflammation in OVA-induced allergic asthma in mice.

No MeSH data available.


Related in: MedlinePlus