Kidney Week

Abstract: FR-PO898

Comparative Proteomic Analysis of Laser Microdissected Glomeruli and Tubules in IgA Nephropathy

Session Information

• IgA Nephropathy: Clinical, Outcomes, and Therapeutics
  October 25, 2024 | Location: Exhibit Hall, Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Glomerular Diseases

• 1402 Glomerular Diseases: Clinical, Outcomes, and Therapeutics

Authors

• Takahashi, Kazuo, Department of Biomedical Molecular Sciences, Fujita Health University School of Medicine, Toyoake, Aichi, Japan

Kazuo Takahashi, MD, PhD

• Tsuji, Yudai, Department of Biomedical Molecular Sciences, Fujita Health University School of Medicine, Toyoake, Aichi, Japan

Yudai Tsuji, PhD

• Saitoh, Sei, Department of Disease Systems Analysis Medicine, School of Medical Sciences, Fujita Health University, Toyoake, Aichi, Japan

Sei Saitoh, MD, PhD

• Ohyama, Yukako, Department of Biomedical Molecular Sciences, Fujita Health University School of Medicine, Toyoake, Aichi, Japan

Yukako Ohyama, MD, PhD

• Hirayama, Masaya, Department of Biomedical Molecular Sciences, Fujita Health University School of Medicine, Toyoake, Aichi, Japan

Masaya Hirayama

• Tsuboi, Naotake, Department of Nephrology, Fujita Health University School of Medicine, Toyoake, Aichi, Japan

Naotake Tsuboi, MD, PhD

Background

IgA nephropathy (IgAN) is the most common glomerulonephritis worldwide, and 30–40% of cases progress to end-stage kidney disease. Although the glomerular mesangium is the leading site of IgA deposition in IgAN, tubulointerstitial lesions vary among patients. A new workflow for laser capture microdissection coupled with mass spectrometry (MS) was developed. Using this workflow for glomeruli and tubules, we attempted to detect molecules associated with the pathogenesis and disease progression in IgAN.

Methods

Using the treatment protocol for IgAN at the Fujita Health University Hospital, patients with IgAN were divided into immunosuppressive (tonsillectomy and steroid pulse therapy, n=19) and conservative (n=14) therapy groups. Glomerular and tubular cross-sections were microdissected from stored formalin-fixed paraffin-embedded kidney biopsy tissues and control kidney tissues (n=10) purchased from OriGene Technologies. Samples were analyzed using liquid chromatography-mass spectrometry, and the relative amounts of glomerular and tubular proteins were compared between the groups.

Results

Glomerular proteomic analysis quantified 1807 proteins, of which 85 had significantly different abundances in patients with IgAN than in controls. Comparing the different treatment groups of patients with IgAN, 78 proteins showed significantly different abundances. These proteins are mainly a part of the complement system and are a group of extracellular matrix proteins.
Tubular proteomic analysis quantified 2354 proteins, of which 73 were significantly differentially expressed between patients with IgAN and controls. When comparing the different IgAN treatment groups, 75 proteins showed significantly different abundances. These proteins include extracellular matrix and epithelial-mesenchymal transition proteins.

Conclusion

Using LMD-coupled MS, we demonstrated that the complement system in the glomerular lesion and the epithelial-mesenchymal transition system in the tubular interstitial lesion differed between different treatment groups. Investigating the relationship between these molecules and kidney prognosis is crucial for discovering new biomarkers to determine kidney prognosis.

Funding

• Private Foundation Support