Regulation of functional phenotypes of cord blood derived eosinophils by gamma-secretase inhibitor.
Eosinophils develop from stem cells in the bone marrow under the influence of hematopoietic cytokines, particularly IL-5. Previously, we have demonstrated that blockage of Notch signaling by a gamma-secretase inhibitor (GSI) promotes the differentiation of umbilical cord blood (UCB)-derived eosinophils. These highly major basic protein (MBP)-positive eosinophils cultured in the presence of the inhibitor lack the migratory response to eotaxin, although their CCR3 levels are similar to those of eosinophils cultured without the inhibitor. We investigated the mechanism underlying the differential responses of differentiating eosinophils and their functionalities in response to eosinophil-active cytokines in the presence and absence of GSI. UCB cells cultured for 4 weeks with hematopoietic cytokines in the presence or absence of GSI were monitored for extracellular signal-regulated kinase (ERK) phosphorylation, MBP expression, and functionality. Eosinophil differentiation from UCB cells was accompanied by activation of the ERK1/2 pathway during the 4-week culture period. In particular, strong ERK1/2 phosphorylation was observed in eosinophils during the final stage of culture when GSI was present. Consistent with this finding, ERK inhibition nullified the effect of GSI on eosinophil differentiation. Eosinophils cultured with GSI resembled airway eosinophils rather than peripheral blood eosinophils based on reduced IL-5Ralpha expression, blunted eosinophil cationic protein (ECP) degranulation, and decreased IL-13 and granulocyte macrophage-colony-stimulating factor production. These results suggest that Notch signaling regulates the terminal differentiation and subsequent effector phenotypes of eosinophils, partly through modulation of the ERK pathway. GSI has therapeutic potential for eosinophilic inflammatory diseases, such as asthma.
Kang
Jin Hyun
JH
Division of Molecular and Life Sciences, College of Science and Technology, Hanyang University, Ansan, South Korea.
Lee
Da Hye
DH
Seo
Hyemyung
H
Park
Jong Sook
JS
Nam
Key Hyun
KH
Shin
Soon Young
SY
Park
Choon-Sik
CS
Chung
Il Yup
IY
D053829:Amyloid Precursor Protein Secretases / Q000037:antagonists & inhibitors*; D000818:Animals; D002070:Butadienes / Q000494:pharmacology; D002454:Cell Differentiation / Q000187:drug effects / Q000502:physiology*; D002478:Cells, Cultured; D004804:Eosinophils / Q000166:cytology* / Q000187:drug effects / Q000201:enzymology*; D005312:Fetal Blood / Q000166:cytology* / Q000187:drug effects / Q000201:enzymology*; D005419:Flavonoids / Q000494:pharmacology; D006801:Humans; D051379:Mice; D009570:Nitriles / Q000494:pharmacology; D011480:Protease Inhibitors / Q000494:pharmacology*
D002070:Butadienes; D005419:Flavonoids; D009570:Nitriles; D011480:Protease Inhibitors; C113580:U 0126; D053829:Amyloid Precursor Protein Secretases; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one