title: Significant increase of plasma tetranectin in ovx mice as defined by proteomics analysis.
abstract: BACKGROUND
  Proteomics is recognized as a useful tool in the dynamic screening of plasma protein expression. This study aimed to identify increased expressions of novel plasma proteins in ovariectomized mice (ovx) using selective reaction monitoring (SRM) validation in combination with electrospray ionized-quadrupole time-of-flight mass spectrometry (ESI-Q-TOF-MS) screening.
  
  
  METHODS
  Twenty-week-old female C57BL/6 mice were ovariectomized or subjected to surgical exposure of the ovaries alone (sham). Blood plasma protein at 4 weeks after these operations was pooled for the ovx and sham group each and separated on SDS-PAGE, and then digested by peptides, which were first differentially displayed by ESI-Q-TOF-MS analysis. Mass spectra of peptides upregulated more than twofold in ovx compared to sham mice were selected for protein identification by ESI-Q-TOF-MS. The selected peptides were further validated in independent samples by SRM using electrospray ionized-triple quadrupole-linear ion trap mass spectrometry (ESI-QqLIT-MS). Optimum transitions for SRM were manually chosen for their high specificity in identifying peptides derived from the candidate proteins.
  
  
  RESULTS
  Differential analysis of peptides revealed 1,108 upregulated peptides in ovx compared with sham control mice. Among the upregulated peptides, 231 nonredundant proteins were identified. Validation analysis for the potential use of these proteins as markers of bone turnover was performed using ESI-QqLIT-MS. The four proteins from the plasma samples, namely mannose-binding lectin-C, major urinary protein 2, type I collagen alpha 2 chain, and tetranectin, were evaluated in a blinded manner. A statistically significant elevation of all four proteins in the plasma of ovx mice was confirmed by SRM. Of the four upregulated plasma proteins, tetranectin increased by almost 50 times in the ovx mice compared with the sham mice.
  
  
  CONCLUSIONS
  On the basis of proteomics analysis, this study demonstrated that four plasma proteins were significantly elevated in the ovx mice; of these, tetranectin was markedly upregulated by almost 50 times compared with the sham mice.
authors.affiliation: Department of Orthopaedic Surgery, Sapporo Medical University, South 1, West 16, Sapporo, 060-8543, Japan, kohichi.sasaki@gmail.com.
authors.forename: Koichi
authors.initials: K
authors.lastname: Sasaki
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Ozasa
authors.forename: Kousuke
authors.initials: K
authors.lastname: Iba
authors.forename: Takuro
authors.initials: T
authors.lastname: Wada
authors.forename: Shin-ichi
authors.initials: S
authors.lastname: Imai
authors.forename: Kayo
authors.initials: K
authors.lastname: Matsumoto
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Sohma
authors.forename: Masato
authors.initials: M
authors.lastname: Aoshima
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Yamashita
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Kokai
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000097:blood; D024042:Collagen Type I / Q000097:blood; D004195:Disease Models, Animal; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D006801:Humans; D037181:Lectins, C-Type / Q000097:blood*; D037601:Mannose-Binding Lectin / Q000097:blood; D051379:Mice; D008810:Mice, Inbred C57BL; D015663:Osteoporosis, Postmenopausal / Q000097:blood* / Q000209:etiology; D010052:Ovariectomy; D011506:Proteins / Q000378:metabolism; D040901:Proteomics; D015203:Reproducibility of Results; D021241:Spectrometry, Mass, Electrospray Ionization
chemical_list: D015415:Biomarkers; D024042:Collagen Type I; D037181:Lectins, C-Type; D037601:Mannose-Binding Lectin; C445639:Mbl2 protein, mouse; D011506:Proteins; C035737:major urinary proteins; C048648:tetranectin