Session Title: Genetics and Genomics of Rheumatic Diseases
Session Type: Abstract Submissions (ACR)
Background/Purpose: To describe proteins with a potential role in OA pathogenesis, in this study we have followed a proteomic approach based on a shotgun comparative analysis of Mesenchymal Stem Cells (MSCs) isolated from OA patients and healthy donors.
Methods: MSCs were obtained from bone marrow aspirates at the time of joint replacement surgery of three OA patients (mean age 76.7 years) and three hip fracture subjects without OA (mean age 73.3). Cells were cultured and expanded. Confluent cells at the third passage (approximately 2 x 106) were used for the experiments. After Protein extraction, solubilization and digestion, samples were subjected to a LC-MS shotgun analysis. For protein identification the MS/MS spectra were extracted using the Proteome Discoverer 1.0 software and searched against the MSIPI human database (version 091510) using the Mascot 2.1 program. GeneCodis 2.0 software was used for functional classification of differential proteins.
Results: A total of 1748 proteins were identified. The statistical analysis revealed 123 differentially expressed proteins between OA-MSCs and control MSCs with foldchange values > 2 times at the p < 0.05 level of significance, of which 76 (~62%) were upregulated and 47 (~38%) were downregulated in OA-MSCs as compared with control cells. Interestingly, five proteosomal proteins, pertaining to the regulation of ubiquitin-protein ligase activity biological function: PSMD2 (2.52), PSMA1 (3.36), PSMB3 (4.56), PSMA3 (7.08) and PSMA4 (13.26) were clearly upregulated.
Conclusion: Given that proteasomal-dependent degradation has a critical role in regulating activities of key osteoblastogenic transcription factors (e.g., RUNX2, ATF4) and signaling pathways (e.g., Hedgehog, BMP, Wnt/β-catenin), upregulation of proteasome subunits and increased activity in MSCs from OA patients might be related to reduced bone mass and/or poor bone tissue quality in OA patients.
J. R. Lamas,
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ACR Meeting Abstracts - https://acrabstracts.org/abstract/proteomic-shotgun-analysis-of-mesenchymal-stem-cells-reveals-an-alterated-regulation-of-proteosomal-proteins-in-osteoarthritis-patients/