ABSTRACT
BACKGROUND: Antibody-mediated rejection (AMR) accounts for >50% of kidney allograft loss. Donor-specific antibodies (DSA) against HLA and non-HLA antigens in the glomeruli and the tubulointerstitium cause AMR while inflammatory cytokines such as TNFα trigger graft injury. The mechanisms governing cell-specific injury in AMR remain unclear. METHODS: Unbiased proteomic analysis of laser-captured and microdissected glomeruli and tubulointerstitium was performed on 30 for-cause kidney biopsy specimens with early AMR, acute cellular rejection (ACR), or acute tubular necrosis (ATN). RESULTS: A total of 107 of 2026 glomerular and 112 of 2399 tubulointerstitial proteins was significantly differentially expressed in AMR versus ACR; 112 of 2026 glomerular and 181 of 2399 tubulointerstitial proteins were significantly dysregulated in AMR versus ATN (P<0.05). Basement membrane and extracellular matrix (ECM) proteins were significantly decreased in both AMR compartments. Glomerular and tubulointerstitial laminin subunit γ-1 (LAMC1) expression decreased in AMR, as did glomerular nephrin (NPHS1) and receptor-type tyrosine-phosphatase O (PTPRO). The proteomic analysis revealed upregulated galectin-1, which is an immunomodulatory protein linked to the ECM, in AMR glomeruli. Anti-HLA class I antibodies significantly increased cathepsin-V (CTSV) expression and galectin-1 expression and secretion in human glomerular endothelial cells. CTSV had been predicted to cleave ECM proteins in the AMR glomeruli. Glutathione S-transferase ω-1, an ECM-modifying enzyme, was significantly increased in the AMR tubulointerstitium and in TNFα-treated proximal tubular epithelial cells. CONCLUSIONS: Basement membranes are often remodeled in chronic AMR. Proteomic analysis performed on laser-captured and microdissected glomeruli and tubulointerstitium identified early ECM remodeling, which may represent a new therapeutic opportunity.
Subject(s)
Basement Membrane/metabolism , Extracellular Matrix/metabolism , Graft Rejection/metabolism , Graft Rejection/pathology , Kidney Glomerulus/pathology , Kidney Tubules/pathology , Adult , Aged , Allografts/metabolism , Allografts/pathology , Antibodies/metabolism , Biopsy , Cathepsins/metabolism , Cell Line , Cysteine Endopeptidases/metabolism , Extracellular Matrix/pathology , Female , Galectin 1/genetics , Galectin 1/metabolism , Gene Expression , Glutathione Transferase/metabolism , Graft Rejection/genetics , Histocompatibility Antigens Class I/immunology , Humans , Kidney Glomerulus/metabolism , Kidney Transplantation , Kidney Tubules/metabolism , Laminin/metabolism , Male , Matrix Metalloproteinase 2/metabolism , Matrix Metalloproteinase 3/metabolism , Membrane Proteins/metabolism , Middle Aged , Necrosis , Proteomics , Receptor-Like Protein Tyrosine Phosphatases, Class 3/metabolism , Tumor Necrosis Factor-alpha/pharmacologyABSTRACT
Given the increasing number of patients with end-stage renal disease in Ontario, there is a need to improve the efficiency and effectiveness of the pretransplant evaluation, to allow for a seamless progression through the various steps in the process. Toronto General Hospital's kidney transplant program is evaluating various performance measures, specifically looking at waiting times from referral to initial evaluation and initial evaluation to final disposition, to use as metrics for monitoring program performance and stimulate quality improvement.
