Transduction of phosphatase and tensin homolog deleted on chromosome 10 into eosinophils attenuates survival, chemotaxis, and airway inflammation.
Phosphatase and tensin homolog deleted on chromosome 10 (PTEN) is part of a complex signaling system that affects a variety of important cell functions. PTEN antagonizes the action of PI3K by dephosphorylating the signaling lipid phosphatidylinositol 3,4,5-triphosphate. In the present study, we used a TAT fusion protein transduction system to elucidate the role of PTEN in eosinophils and airway inflammation. A small region of the HIV TAT protein (YGRKKRRQRRR), a protein transduction domain known to enter mammalian cells efficiently, was fused to the N terminus of PTEN. Flow cytometric analysis of annexin V- and propidium iodide-stained cells was used to assess eosinophil survival. A chemotaxis assay was performed using a Boyden chamber. Cell analysis in bronchoalveolar lavage fluid and histological examinations were performed using OVA-challenged A/J mice. We found that TAT-PTEN was successfully internalized into eosinophils and functioned as a phosphatase in situ. TAT-PTEN, but not a TAT-GFP control protein, blocked the ability of IL-5 to prevent the apoptosis of eosinophils from allergic subjects. The eotaxin-induced eosinophil chemotaxis was inhibited by TAT-PTEN in a dose-dependent manner. Intranasal pretreatment with TAT-PTEN, but not TAT-GFP, significantly inhibited the OVA-induced eosinophil infiltration in bronchoalveolar lavage fluid. Histological examination of the lung, including H&E and Alcian blue/periodic acid-Schiff staining, revealed that TAT-PTEN, but not TAT-GFP, abrogated eosinophilic inflammation and mucus production. Our results suggest that PTEN negatively regulates eosinophil survival, chemotaxis, and allergic inflammation. The pharmacological targeting of PTEN may constitute a new strategy for the treatment of eosinophilic disorders.
Adachi
Tetsuya
T
Department of Internal Medicine, Teikyo University School of Medicine, Tokyo, Japan. tadachi@med.teikyo-u.ac.jp
Hanaka
Satoko
S
Masuda
Tomoko
T
Yoshihara
Hisanao
H
Nagase
Hiroyuki
H
Ohta
Ken
K
D000595:Amino Acid Sequence; D000818:Animals; D002470:Cell Survival; D002633:Chemotaxis; D004804:Eosinophils / Q000201:enzymology / Q000276:immunology*; D006801:Humans; D051379:Mice; D008815:Mice, Inbred Strains; D008969:Molecular Sequence Data; D051059:PTEN Phosphohydrolase / Q000235:genetics / Q000378:metabolism*; D011014:Pneumonia / Q000276:immunology* / Q000473:pathology; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D014161:Transduction, Genetic; D054322:tat Gene Products, Human Immunodeficiency Virus / Q000235:genetics / Q000378:metabolism
D011993:Recombinant Fusion Proteins; C526890:TAT-PTEN fusion protein; D054322:tat Gene Products, Human Immunodeficiency Virus; D051059:PTEN Phosphohydrolase; C494929:PTEN protein, human