title: Comparative proteome analysis of wild-type and klotho-knockout mouse kidneys using a combination of MALDI-IMS and LC-MS/MS.
abstract: Mutation of the klotho gene in mice elicits a syndrome resembling accelerated human aging. However, there is limited evidence for the role of Klotho in the kidney. We conducted a comparative proteome analysis of wild-type (WT) and klotho-knockout (kl-/-) mouse kidneys to identify proteins involved in Klotho deficiency.
  
  
  
  MALDI imaging MS (MALDI-IMS) of frozen kidney sections from 7-wk-old male WT and kl-/-mice was used to determine genotype-specific differences in the MS distribution. Proteins uniquely distributed in kl-/-kidneys were identified by subsequent analysis of adjacent trypsinized sections by MALDI-IMS in combination with LC-MS/MS. Immunohistochemistry and western blotting were adopted in qualitative and quantitation analysis.
  
  
  
  Ninety-seven and 69 proteins identified by LC-MS/MS were matched to the MALDI-IMS spectra in WT and kl-/-mouse kidneys, respectively. Among protein types matched, nucleic acid binding proteins were most abundant, followed by enzymes. We identified secretogranin-1 (SCG1), which was predominately distributed in the glomeruli and renal tubules of kl-/-mouse kidneys. Immunohistochemistry for SCG1 mirrored images of MALDI-IMS.
  
  
  
  SCG1 may be a candidate protein involved in Klotho deficiency. Although further research is needed to investigate the role of SCG1 in the kidney, we show the usefulness of MALDI-IMS combined with LC-MS/MS.
authors.affiliation: Department of Special Care Dentistry, Hiroshima University Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan.
authors.forename: Yoko
authors.initials: Y
authors.lastname: Fujino
authors.affiliation: Department of Calcified Tissue Biology, Hiroshima University Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan.
authors.forename: Tomoko
authors.initials: T
authors.lastname: Minamizaki
authors.affiliation: Central Laboratory, Hiroshima University Faculty of Dentistry, Hiroshima, Japan.
authors.forename: Ikue
authors.initials: I
authors.lastname: Hayashi
authors.affiliation: Advanced Science Research Center, Okayama University, Okayama, Japan.
authors.forename: Asako
authors.initials: A
authors.lastname: Kawakami
authors.affiliation: Advanced Science Research Center, Okayama University, Okayama, Japan.
authors.forename: Takaaki
authors.initials: T
authors.lastname: Miyaji
authors.affiliation: Department of Pediatric Dentistry, Hiroshima University Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan.
authors.forename: Kaoru
authors.initials: K
authors.lastname: Sakurai
authors.affiliation: Department of Calcified Tissue Biology, Hiroshima University Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan.
authors.forename: Hirotaka
authors.initials: H
authors.lastname: Yoshioka
authors.affiliation: Department of Pediatric Dentistry, Hiroshima University Institute of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan.
authors.forename: Katsuyuki
authors.initials: K
authors.lastname: Kozai
authors.affiliation: Special Care Dentistry, Hiroshima University Hospital, Hiroshima, Japan.
authors.forename: Mitsugi
authors.initials: M
authors.lastname: Okada
authors.affiliation: Department of Calcified Tissue Biology, Hiroshima University Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Yoshiko
mesh_terms: D000818:Animals; D002853:Chromatography, Liquid; D005966:Glucuronidase / Q000172:deficiency* / Q000235:genetics*; D007668:Kidney / Q000378:metabolism*; D000090265:Klotho Proteins; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D040901:Proteomics / Q000379:methods*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D053719:Tandem Mass Spectrometry
chemical_list: D005966:Glucuronidase; D000090265:Klotho Proteins
keywords: Kidney; Klotho; MALDI-IMS