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Expression of neuroimmune semaphorins 4A and 4D and their receptors in the lung is enhanced by allergen and vascular endothelial growth factor.

Smith EP, Shanks K, Lipsky MM, DeTolla LJ, Keegan AD, Chapoval SP - BMC Immunol. (2011)

Bottom Line: Sema4A and Sema4D were the first semaphorins found to be expressed on immune cells and were termed "immune semaphorins".We found that besides accessory-like cells, Sema4A was also detected on bronchial epithelial and smooth muscle cells, whereas Sema4D expression was high on immune cells such as T and B lymphocytes.CD72 was found on lung immune, inflammatory, and epithelial cells.

View Article: PubMed Central - HTML - PubMed

Affiliation: Center for Vascular and Inflammatory Diseases, University of Maryland School of Medicine, Baltimore, Maryland 21201, USA.

ABSTRACT

Background: Semaphorins were originally identified as molecules regulating a functional activity of axons in the nervous system. Sema4A and Sema4D were the first semaphorins found to be expressed on immune cells and were termed "immune semaphorins". It is known that Sema4A and Sema4D bind Tim-2 and CD72 expressed on leukocytes and PlexinD1 and B1 present on non-immune cells. These neuroimmune semaphorins and their receptors have been shown to play critical roles in many physiological and pathological processes including neuronal development, immune response regulation, cancer, autoimmune, cardiovascular, renal, and infectious diseases. However, the expression and regulation of Sema4A, Sema4D, and their receptors in normal and allergic lungs is undefined.

Results: Allergen treatment and lung-specific vascular endothelial growth factor (VEGF) expression induced asthma-like pathologies in the murine lungs. These experimental models of allergic airway inflammation were used for the expression analysis of immune semaphorins and their receptors employing immunohistochemistry and flow cytometry techniques. We found that besides accessory-like cells, Sema4A was also detected on bronchial epithelial and smooth muscle cells, whereas Sema4D expression was high on immune cells such as T and B lymphocytes. Surprisingly, under inflammation various cell types including macrophages, lymphocytes, and granulocytes in the lung expressed Tim-2, a previously defined marker for Th2 cells. CD72 was found on lung immune, inflammatory, and epithelial cells. Bronchial epithelial cells were positive for both plexins, whereas some endothelial cells selectively expressed Plexin D1. Plexin B1 expression was also detected on lung DC. Both allergen and VEGF upregulated the expression of neuroimmune semaphorins and their receptors in the lung tissue. However, the lung tissue Sema4A-Tim2 expression was rather weak, whereas Sema4D-CD72 ligand-receptor pair was vastly upregulated by allergen. Soluble Sema4D protein was present in the lung lysates and a whole Sema4A protein plus its dimer were readily detected in the bronchoalveolar (BAL) fluids under inflammation.

Conclusions: This study clearly shows that neuroimmune semaphorins Sema4A and Sema4D and their receptors might serve as potential markers for the allergic airway inflammatory diseases. Our current findings pave the way for further investigations of the role of immune semaphorins in inflammation and their use as potential therapeutic targets for the inflammatory lung conditions.

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Plexin B1 and Plexin D1 expression in the mouse lung tissue and its regulation by either allergen or transgenic VEGF exposure. (A) Plexin B1 expression was detected on selected bronchial epithelial cells in control WT mice with increased expression in allergen-treated mice. Under inflammatory condition, its expression was detected on a number of APC-like cells (insert, red arrow). Plexin D1 expression was restricted to endothelial and a number of bronchial epithelial cells. In addition, Plexin D1 was found on underlining epithelium cells (insert, red arrow). (B) Plexin B1 expression on lung conventional DC under inflammation. WT mice were treated with OVA as described in Materials and Methods and lung cDC were identified as CD11c+MHCII+ cells which were gated for further analysis. The histograms show the percentage of Plexin B1+ gated cDC (clear histogram) as compared to the appropriate isotype control stained cells (gray histogram). (C) Notable upregulation of the expression of both Plexins in VEGF tg lungs was mainly targeted to inflammatory macrophages found in the interstitial spaces.
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Figure 6: Plexin B1 and Plexin D1 expression in the mouse lung tissue and its regulation by either allergen or transgenic VEGF exposure. (A) Plexin B1 expression was detected on selected bronchial epithelial cells in control WT mice with increased expression in allergen-treated mice. Under inflammatory condition, its expression was detected on a number of APC-like cells (insert, red arrow). Plexin D1 expression was restricted to endothelial and a number of bronchial epithelial cells. In addition, Plexin D1 was found on underlining epithelium cells (insert, red arrow). (B) Plexin B1 expression on lung conventional DC under inflammation. WT mice were treated with OVA as described in Materials and Methods and lung cDC were identified as CD11c+MHCII+ cells which were gated for further analysis. The histograms show the percentage of Plexin B1+ gated cDC (clear histogram) as compared to the appropriate isotype control stained cells (gray histogram). (C) Notable upregulation of the expression of both Plexins in VEGF tg lungs was mainly targeted to inflammatory macrophages found in the interstitial spaces.

Mentions: Lastly, we performed IHC to define the lung tissue distribution of Plexins D1 and B1, corresponding Sema4A and Sema4D non-immune cell receptors. Previous studies have shown both plexins to be expressed on endothelial cells [26,27]. However, we showed here that mouse lung endothelial cells did not stain positively for Plexin B1 (Figure 6 A). Around 20% of the lung bronchi and bronchioles were found to express Plexin B1 while most of them were marker-negative. OVA treatment upregulated this level to more than 50% of corresponding airways (Figure 6 A). In addition, Plexin B1 expression was noted on APC-like cells in the lung tissue. This was supported by the flow cytometry study which demonstrated Plexin B1 expression on lung cDC (Figure 6 B).


Expression of neuroimmune semaphorins 4A and 4D and their receptors in the lung is enhanced by allergen and vascular endothelial growth factor.

Smith EP, Shanks K, Lipsky MM, DeTolla LJ, Keegan AD, Chapoval SP - BMC Immunol. (2011)

Plexin B1 and Plexin D1 expression in the mouse lung tissue and its regulation by either allergen or transgenic VEGF exposure. (A) Plexin B1 expression was detected on selected bronchial epithelial cells in control WT mice with increased expression in allergen-treated mice. Under inflammatory condition, its expression was detected on a number of APC-like cells (insert, red arrow). Plexin D1 expression was restricted to endothelial and a number of bronchial epithelial cells. In addition, Plexin D1 was found on underlining epithelium cells (insert, red arrow). (B) Plexin B1 expression on lung conventional DC under inflammation. WT mice were treated with OVA as described in Materials and Methods and lung cDC were identified as CD11c+MHCII+ cells which were gated for further analysis. The histograms show the percentage of Plexin B1+ gated cDC (clear histogram) as compared to the appropriate isotype control stained cells (gray histogram). (C) Notable upregulation of the expression of both Plexins in VEGF tg lungs was mainly targeted to inflammatory macrophages found in the interstitial spaces.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3118960&req=5

Figure 6: Plexin B1 and Plexin D1 expression in the mouse lung tissue and its regulation by either allergen or transgenic VEGF exposure. (A) Plexin B1 expression was detected on selected bronchial epithelial cells in control WT mice with increased expression in allergen-treated mice. Under inflammatory condition, its expression was detected on a number of APC-like cells (insert, red arrow). Plexin D1 expression was restricted to endothelial and a number of bronchial epithelial cells. In addition, Plexin D1 was found on underlining epithelium cells (insert, red arrow). (B) Plexin B1 expression on lung conventional DC under inflammation. WT mice were treated with OVA as described in Materials and Methods and lung cDC were identified as CD11c+MHCII+ cells which were gated for further analysis. The histograms show the percentage of Plexin B1+ gated cDC (clear histogram) as compared to the appropriate isotype control stained cells (gray histogram). (C) Notable upregulation of the expression of both Plexins in VEGF tg lungs was mainly targeted to inflammatory macrophages found in the interstitial spaces.
Mentions: Lastly, we performed IHC to define the lung tissue distribution of Plexins D1 and B1, corresponding Sema4A and Sema4D non-immune cell receptors. Previous studies have shown both plexins to be expressed on endothelial cells [26,27]. However, we showed here that mouse lung endothelial cells did not stain positively for Plexin B1 (Figure 6 A). Around 20% of the lung bronchi and bronchioles were found to express Plexin B1 while most of them were marker-negative. OVA treatment upregulated this level to more than 50% of corresponding airways (Figure 6 A). In addition, Plexin B1 expression was noted on APC-like cells in the lung tissue. This was supported by the flow cytometry study which demonstrated Plexin B1 expression on lung cDC (Figure 6 B).

Bottom Line: Sema4A and Sema4D were the first semaphorins found to be expressed on immune cells and were termed "immune semaphorins".We found that besides accessory-like cells, Sema4A was also detected on bronchial epithelial and smooth muscle cells, whereas Sema4D expression was high on immune cells such as T and B lymphocytes.CD72 was found on lung immune, inflammatory, and epithelial cells.

View Article: PubMed Central - HTML - PubMed

Affiliation: Center for Vascular and Inflammatory Diseases, University of Maryland School of Medicine, Baltimore, Maryland 21201, USA.

ABSTRACT

Background: Semaphorins were originally identified as molecules regulating a functional activity of axons in the nervous system. Sema4A and Sema4D were the first semaphorins found to be expressed on immune cells and were termed "immune semaphorins". It is known that Sema4A and Sema4D bind Tim-2 and CD72 expressed on leukocytes and PlexinD1 and B1 present on non-immune cells. These neuroimmune semaphorins and their receptors have been shown to play critical roles in many physiological and pathological processes including neuronal development, immune response regulation, cancer, autoimmune, cardiovascular, renal, and infectious diseases. However, the expression and regulation of Sema4A, Sema4D, and their receptors in normal and allergic lungs is undefined.

Results: Allergen treatment and lung-specific vascular endothelial growth factor (VEGF) expression induced asthma-like pathologies in the murine lungs. These experimental models of allergic airway inflammation were used for the expression analysis of immune semaphorins and their receptors employing immunohistochemistry and flow cytometry techniques. We found that besides accessory-like cells, Sema4A was also detected on bronchial epithelial and smooth muscle cells, whereas Sema4D expression was high on immune cells such as T and B lymphocytes. Surprisingly, under inflammation various cell types including macrophages, lymphocytes, and granulocytes in the lung expressed Tim-2, a previously defined marker for Th2 cells. CD72 was found on lung immune, inflammatory, and epithelial cells. Bronchial epithelial cells were positive for both plexins, whereas some endothelial cells selectively expressed Plexin D1. Plexin B1 expression was also detected on lung DC. Both allergen and VEGF upregulated the expression of neuroimmune semaphorins and their receptors in the lung tissue. However, the lung tissue Sema4A-Tim2 expression was rather weak, whereas Sema4D-CD72 ligand-receptor pair was vastly upregulated by allergen. Soluble Sema4D protein was present in the lung lysates and a whole Sema4A protein plus its dimer were readily detected in the bronchoalveolar (BAL) fluids under inflammation.

Conclusions: This study clearly shows that neuroimmune semaphorins Sema4A and Sema4D and their receptors might serve as potential markers for the allergic airway inflammatory diseases. Our current findings pave the way for further investigations of the role of immune semaphorins in inflammation and their use as potential therapeutic targets for the inflammatory lung conditions.

Show MeSH
Related in: MedlinePlus