Compartmentalized transgene expression of granulocyte-macrophage colony-stimulating factor (GM-CSF) in mouse lung enhances allergic airways inflammation.
To investigate the role of GM-CSF in asthmatic airways inflammation, we have targeted GM-CSF transgene to the airway cells in a mouse model of ovalbumin (OVA)-induced allergic airways inflammation, a model in which there is marked induction of endogenous IL-5 and IL-4 but not GM-CSF. Following intranasal delivery of a replication-deficient adenoviral gene transfer vector (Ad), transgene expression was found localized primarily to the respiratory epithelial cells. Intranasal delivery of 0.03 x 10(9) plaque-forming units (PFU) of AdGM-CSF into naive BALB/c mice resulted in prolonged and compartmentalized release of GM-CSF transgene protein with a peak concentration of approximately 80 pg/ml detected in bronchoalveolar lavage fluid (BALF) at day 7, but little in serum. These levels of local GM-CSF expression per se resulted in no eosinophilia and only a minimum of tissue inflammatory responses in the lung of naive mice, similar to those induced by the control vector. However, such GM-CSF expression in the airways of OVA-sensitized mice resulted in a much greater and sustained accumulation of various inflammatory cell types, most noticeably eosinophils, both in BALF and airway tissues for 15-21 days post-OVA aerosol challenge, at which times airways inflammation had largely resolved in control mice. While the levels of IL-5 and IL-4 in BALF and the rate of eosinophil apoptosis were found similar between different treatments, there was an increased number of proliferative leucocytes in the lung receiving GM-CSF gene transfer. Our results thus provide direct experimental evidence that GM-CSF can significantly contribute to the development of allergic airways inflammation through potentiating and prolonging inflammatory infiltration induced by cytokines such as IL-5 and IL-4.
Lei
X F
XF
Department of Pathology, McMaster University, Hamilton, Ontario, Canada.
Ohkawara
Y
Y
Stämpfli
M R
MR
Gauldie
J
J
Croitoru
K
K
Jordana
M
M
Xing
Z
Z
D000256:Adenoviridae / Q000235:genetics; D000818:Animals; D017209:Apoptosis; D001249:Asthma / Q000276:immunology*; D001992:Bronchoalveolar Lavage Fluid / Q000166:cytology / Q000276:immunology; D004847:Epithelial Cells / Q000276:immunology*; D005260:Female; D018390:Gene Targeting; D005822:Genetic Vectors; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology*; D015847:Interleukin-4 / Q000032:analysis; D015848:Interleukin-5 / Q000032:analysis; D008168:Lung / Q000276:immunology* / Q000473:pathology; D051379:Mice; D008807:Mice, Inbred BALB C; D010047:Ovalbumin / Q000276:immunology; D019076:Transgenes
D015848:Interleukin-5; D015847:Interleukin-4; D016178:Granulocyte-Macrophage Colony-Stimulating Factor; D010047:Ovalbumin