Inhibitory Action of alpha1-Anti-Trypsin on Proinflammatory Mediators Expression in Human Endometrial Stromal Cells

Presentation Number: SUN-0037
Date of Presentation: June 22nd, 2014

Kazuhiro Tamura*1, Keiko Fumoto1, Masumi Otsu1, Mikihiro Yoshie1, Takeshi Kajihara2, Osamu Ishihara2, Keiichi Isaka3 and Eiichi Tachikawa1
1Tokyo University of Pharmacy & Life Sciences, Tokyo, Japan, 2Saitama Medical University, Saitama, Japan, 3Tokyo Medical University, Tokyo, Japan

Abstract

The molecular mechanisms underlying the onset and progression of endometriosis are still poorly understood. Our previous study has shown that distinct endometriosis-like lesions were created by injecting a suspension of human endometrial cells into BALB/c nude female mice that underwent unilateral ovariectomy (uOVX) compared with control non-uOVX mice. We observed that the lesions in uOVX animals express high levels of IL-6 and prostaglandin (PG) E2, and that peritoneal bleeding may stimulate the expression of proinflammatory mediators partly through protease-activated receptor (PAR) activation. In the present study, alpha 1-antitrypsin (α1-AT) was identified as a protein that significantly decreased in the lesion of uOVX mice by 2-dimentional gel electrophoresis, followed by MALDI-TOF MS. To understand the biological significance of α1-AT in the endometriosis-like lesions, the lesions were harvested for immunohistochemical analysis and immunoblotting for several signaling pathways. The levels of phosphorylated Akt, mammalian target of rapamycin (mTOR), p70 ribosomal S6 kinase, and NFκB were higher in endometriosis-like lesions from the uOVX group than control. The lesions mostly comprised stromal cells. The bioactivity of α1-AT was assessed by investigating inflammatory factors expression in PAR-stimulated endometrial stromal cells in vitro. PAR promoted the expression of IL-8 and cyclooxygenase (COX)-2, and the phosphorylation of ERK and p38MAPK. Treatment with α1-AT (0.5 mg/ml) inhibited the IL-8 and COX-2 expression with no changes in the activation of Akt, NFκB, and MAPK signaling pathways. PGE2 (0.5 µM) and EGF (50 ng/ml) significantly enhanced PAR1 agonist (thrombin)-stimulated COX-2 and IL-8 expression, respectively, and α1-AT protein also blocked these expressions. These results suggest that α1-AT posseses the anti-inflammatory activity beyond its role as an antiprotease. Our results illustrate that exacerbated inflammatory reaction in the xenograft mouse model may be caused partly by the dysregulation of α1-AT, suggesting the possible involvement of α1-AT in the pathophysiology of endometriosis.

 

Nothing to Disclose: KT, KF, MO, MY, TK, OI, KI, ET