title: Assessing Amide Proton Transfer (APT) MRI Contrast Origins in 9 L Gliosarcoma in the Rat Brain Using Proteomic Analysis.
abstract: OBJECTIVE
  To investigate the biochemical origin of the amide photon transfer (APT)-weighted hyperintensity in brain tumors.
  
  
  METHODS
  Seven 9 L gliosarcoma-bearing rats were imaged at 4.7 T. Tumor and normal brain tissue samples of equal volumes were prepared with a coronal rat brain matrix and a tissue biopsy punch. The total tissue protein and the cytosolic subproteome were extracted from both samples. Protein samples were analyzed using two-dimensional gel electrophoresis, and the proteins with significant abundance changes were identified by mass spectrometry.
  
  
  RESULTS
  There was a significant increase in the cytosolic protein concentration in the tumor, compared to normal brain regions, but the total protein concentrations were comparable. The protein profiles of the tumor and normal brain tissue differed significantly. Six cytosolic proteins, four endoplasmic reticulum proteins, and five secreted proteins were considerably upregulated in the tumor.
  
  
  CONCLUSIONS
  Our experiments confirmed an increase in the cytosolic protein concentration in tumors and identified several key proteins that may cause APT-weighted hyperintensity.
authors.affiliation: Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
authors.forename: Kun
authors.initials: K
authors.lastname: Yan
authors.forename: Zongming
authors.initials: Z
authors.lastname: Fu
authors.forename: Chen
authors.initials: C
authors.lastname: Yang
authors.forename: Kai
authors.initials: K
authors.lastname: Zhang
authors.forename: Shanshan
authors.initials: S
authors.lastname: Jiang
authors.forename: Dong-Hoon
authors.initials: DH
authors.lastname: Lee
authors.forename: Hye-Young
authors.initials: HY
authors.lastname: Heo
authors.forename: Yi
authors.initials: Y
authors.lastname: Zhang
authors.forename: Robert N
authors.initials: RN
authors.lastname: Cole
authors.forename: Jennifer E
authors.initials: JE
authors.lastname: Van Eyk
authors.forename: Jinyuan
authors.initials: J
authors.lastname: Zhou
mesh_terms: D000818:Animals; D001921:Brain / Q000473:pathology*; D001932:Brain Neoplasms / Q000737:chemistry / Q000378:metabolism*; D018316:Gliosarcoma / Q000737:chemistry / Q000378:metabolism*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D020543:Proteome / Q000032:analysis* / Q000378:metabolism; D040901:Proteomics; D051381:Rats; D011916:Rats, Inbred F344; D015854:Up-Regulation
chemical_list: D020543:Proteome