Comparative proteome analysis of wild‐type and klotho‐knockout mouse kidneys using a combination of MALDI‐IMS and LC‐MS/MS

• Published in: Proteomics. Clinical applications Vol. 11; no. 7-8
• Main Authors: Fujino, Yoko, Minamizaki, Tomoko, Hayashi, Ikue, Kawakami, Asako, Miyaji, Takaaki, Sakurai, Kaoru, Yoshioka, Hirotaka, Kozai, Katsuyuki, Okada, Mitsugi, Yoshiko, Yuji
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 01-07-2017
• Subjects: Animals; Chromatography, Liquid; Enzymes; Experimental design; Glucuronidase - deficiency; Glucuronidase - genetics; Immunohistochemistry; Kidney; Kidney - metabolism; Kidneys; Klotho; Klotho protein; MALDI‐IMS; Male; Mice; Mice, Knockout; Mutation; Nucleic acids; Protein deficiency; Proteins; Proteomes; Proteomics - methods; Qualitative analysis; Quantitation; Renal tubules; Rodents; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Tandem Mass Spectrometry; Western blotting; MALDI-IMS; Klotho; Kidney
• ISSN: 1862-8346; 1862-8354
• DOI: 10.1002/prca.201600095

Purpose
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.
Experimental design
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.
Results
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.
Conclusions
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.