title: [Study of altered expression of annexin IV and human endometrial receptivity].
abstract: OBJECTIVE
  To explore the association of altered expression of annexin IV in human endometrium during the implantation window and endometrial receptivity.
  
  
  METHODS
  A comparative proteomic strategy, in a combination of two-dimensional fluorescence difference gel electrophoresis (2D-DIGE) and matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF-MS), was adopted to search for proteome alternations of pre-receptive (day LH + 2) versus receptive (LH + 7) endometria. The location and abundance of the identified differentially expressed protein- annexin IV were analyzed by immunostaining and western blot.
  
  
  RESULTS
  By comparing protein profiles of LH + 2 and LH + 7 samples, we found a protein up-regulated 2.12 times in LH + 7 samples, with a relative molecular weight of 36,000 and an isoelectric point near pH 5.8. It was characterized using mass spectrometry and was identified as annexin IV. Immunohistochemical analysis revealed an altered localization of annexin IV--in the epithelia on day LH + 2, and both in the epithelia and stroma cells on day LH + 7. Protein levels of annexin IV were up-regulated on day LH + 7 compared with that on day LH + 2 by Western blot. Integrated optical density of the object (OPTDI) was 46.249 +/- 32.376 and 249.507 +/- 31.959, respectively (P = 0.004).
  
  
  CONCLUSIONS
  Our study indicates endometrial samples obtained by microbiopsy are available for proteomics studies. It seems possible that the increased expression of annexin IV during the implantation window plays an important role in the morphological differentiation of the uterus to the receptive state.
authors.affiliation: Reproductive Medical Center, First Affiliated Hospital of Sun Yat-sen University, Guangzhou 510080, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Li
authors.forename: Zhen
authors.initials: Z
authors.lastname: Tan
authors.forename: Ming-Tao
authors.initials: MT
authors.lastname: Li
authors.forename: Yu-Lin
authors.initials: YL
authors.lastname: Liu
authors.forename: Qun
authors.initials: Q
authors.lastname: Liu
authors.forename: Xiong-Fei
authors.initials: XF
authors.lastname: Gu
authors.forename: Jian-Zhong
authors.initials: JZ
authors.lastname: Zhou
authors.forename: Guang-Lun
authors.initials: GL
authors.lastname: Zhuang
mesh_terms: D000328:Adult; D017314:Annexin A4 / Q000096:biosynthesis*; D015153:Blotting, Western; D015180:Electrophoresis, Gel, Two-Dimensional / Q000379:methods; D010064:Embryo Implantation / Q000502:physiology; D004717:Endometrium / Q000378:metabolism*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008597:Menstrual Cycle / Q000502:physiology*; D011247:Pregnancy; D040901:Proteomics; D011960:Receptors, Estrogen / Q000378:metabolism; D016201:Receptors, Lymphocyte Homing / Q000378:metabolism; D011980:Receptors, Progesterone / Q000378:metabolism; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods; D013997:Time Factors
chemical_list: D017314:Annexin A4; D011960:Receptors, Estrogen; D016201:Receptors, Lymphocyte Homing; D011980:Receptors, Progesterone