Abstract
Excessive activation of inflammatory macrophages drives the pathogenesis of many chronic diseases. EP4 receptor-associated protein (EPRAP) has been identified as a novel, anti-inflammatory molecule in macrophages. In this study, we investigated the role of EPRAP using a murine model of bleomycin (BLM)-induced pulmonary inflammation. When compared with wild-type mice, EPRAP-deficient mice exhibited significantly higher mortality, and increased accumulation of macrophages and proinflammatory molecules in the lung 7 d post-BLM administration. Accordingly, the levels of phosphorylated p105, MEK1/2, and ERK1/2 were elevated in EPRAP-deficient alveolar macrophages following BLM administration. In contrast, macrophage-specific EPRAP overexpression decreased the production of proinflammatory cytokines and chemokines, suggesting that EPRAP in macrophages plays a key role in attenuating BLM-induced pulmonary inflammation. As EPRAP is phosphorylated after translation, we examined the role of posttranslational modifications in cellular inflammatory activation using mouse embryo fibroblasts (MEFs) expressing mutant EPRAP proteins. Expression of mutant EPRAP, in which serine-108 and serine-608 were replaced with alanine (EPRAP S108A/S608A), markedly suppressed TNF-a production in LPS-treated MEFs. Conversely, the serine phosphatase 2A (PP2A) inhibitor, cantharidic acid, increased LPS-induced TNF-α production in MEFs expressing wild-type EPRAP, but not in MEFs expressing EPRAP S108A/S608A. Immunoprecipitation analyses demonstrated that EPRAP associated with PP2A in both MEFs and alveolar macrophages from BLM-treated mice. Our data suggest that PP2A dephosphorylates EPRAP, which may be a crucial step in exertion of its anti-inflammatory properties. For these reasons, we believe the EPRAP-PP2A axis in macrophages holds the key to treating chronic inflammatory disorders.
| Original language | English |
|---|---|
| Pages (from-to) | 4436-4443 |
| Number of pages | 8 |
| Journal | Journal of Immunology |
| Volume | 197 |
| Issue number | 11 |
| DOIs | |
| Publication status | Published - Dec 1 2016 |
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All Science Journal Classification (ASJC) codes
- Immunology and Allergy
- Immunology
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EP4 receptor-associated protein in macrophages protects against bleomycin-induced pulmonary inflammation in mice. / Higuchi, Sei; Fujikawa, Risako; Ikedo, Taichi; Hayashi, Kosuke; Yasui, Mika; Nagata, Manabu; Nakatsuji, Masato; Yokode, Masayuki; Minami, Manabu.
In: Journal of Immunology, Vol. 197, No. 11, 01.12.2016, p. 4436-4443.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - EP4 receptor-associated protein in macrophages protects against bleomycin-induced pulmonary inflammation in mice
AU - Higuchi, Sei
AU - Fujikawa, Risako
AU - Ikedo, Taichi
AU - Hayashi, Kosuke
AU - Yasui, Mika
AU - Nagata, Manabu
AU - Nakatsuji, Masato
AU - Yokode, Masayuki
AU - Minami, Manabu
PY - 2016/12/1
Y1 - 2016/12/1
N2 - Excessive activation of inflammatory macrophages drives the pathogenesis of many chronic diseases. EP4 receptor-associated protein (EPRAP) has been identified as a novel, anti-inflammatory molecule in macrophages. In this study, we investigated the role of EPRAP using a murine model of bleomycin (BLM)-induced pulmonary inflammation. When compared with wild-type mice, EPRAP-deficient mice exhibited significantly higher mortality, and increased accumulation of macrophages and proinflammatory molecules in the lung 7 d post-BLM administration. Accordingly, the levels of phosphorylated p105, MEK1/2, and ERK1/2 were elevated in EPRAP-deficient alveolar macrophages following BLM administration. In contrast, macrophage-specific EPRAP overexpression decreased the production of proinflammatory cytokines and chemokines, suggesting that EPRAP in macrophages plays a key role in attenuating BLM-induced pulmonary inflammation. As EPRAP is phosphorylated after translation, we examined the role of posttranslational modifications in cellular inflammatory activation using mouse embryo fibroblasts (MEFs) expressing mutant EPRAP proteins. Expression of mutant EPRAP, in which serine-108 and serine-608 were replaced with alanine (EPRAP S108A/S608A), markedly suppressed TNF-a production in LPS-treated MEFs. Conversely, the serine phosphatase 2A (PP2A) inhibitor, cantharidic acid, increased LPS-induced TNF-α production in MEFs expressing wild-type EPRAP, but not in MEFs expressing EPRAP S108A/S608A. Immunoprecipitation analyses demonstrated that EPRAP associated with PP2A in both MEFs and alveolar macrophages from BLM-treated mice. Our data suggest that PP2A dephosphorylates EPRAP, which may be a crucial step in exertion of its anti-inflammatory properties. For these reasons, we believe the EPRAP-PP2A axis in macrophages holds the key to treating chronic inflammatory disorders.
AB - Excessive activation of inflammatory macrophages drives the pathogenesis of many chronic diseases. EP4 receptor-associated protein (EPRAP) has been identified as a novel, anti-inflammatory molecule in macrophages. In this study, we investigated the role of EPRAP using a murine model of bleomycin (BLM)-induced pulmonary inflammation. When compared with wild-type mice, EPRAP-deficient mice exhibited significantly higher mortality, and increased accumulation of macrophages and proinflammatory molecules in the lung 7 d post-BLM administration. Accordingly, the levels of phosphorylated p105, MEK1/2, and ERK1/2 were elevated in EPRAP-deficient alveolar macrophages following BLM administration. In contrast, macrophage-specific EPRAP overexpression decreased the production of proinflammatory cytokines and chemokines, suggesting that EPRAP in macrophages plays a key role in attenuating BLM-induced pulmonary inflammation. As EPRAP is phosphorylated after translation, we examined the role of posttranslational modifications in cellular inflammatory activation using mouse embryo fibroblasts (MEFs) expressing mutant EPRAP proteins. Expression of mutant EPRAP, in which serine-108 and serine-608 were replaced with alanine (EPRAP S108A/S608A), markedly suppressed TNF-a production in LPS-treated MEFs. Conversely, the serine phosphatase 2A (PP2A) inhibitor, cantharidic acid, increased LPS-induced TNF-α production in MEFs expressing wild-type EPRAP, but not in MEFs expressing EPRAP S108A/S608A. Immunoprecipitation analyses demonstrated that EPRAP associated with PP2A in both MEFs and alveolar macrophages from BLM-treated mice. Our data suggest that PP2A dephosphorylates EPRAP, which may be a crucial step in exertion of its anti-inflammatory properties. For these reasons, we believe the EPRAP-PP2A axis in macrophages holds the key to treating chronic inflammatory disorders.
UR - http://www.scopus.com/inward/record.url?scp=84996537039&partnerID=8YFLogxK
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U2 - 10.4049/jimmunol.1502618
DO - 10.4049/jimmunol.1502618
M3 - Article
C2 - 27799315
AN - SCOPUS:84996537039
VL - 197
SP - 4436
EP - 4443
JO - Journal of Immunology
JF - Journal of Immunology
SN - 0022-1767
IS - 11
ER -