Filamin B and CD13 Are Components of Senescent Secretomes That May Be Involved in Primary (Stress Induced) and Paracrine Senescence of Mesenchymal Stromal Cells

Objective: In the present study we aim to evaluate whether some of the proteins previously identified in the secretome of senescent bone marrow (BM)- and adipose (A)-mesenchymal stromal cells (MSCs) could be involved in regulation of senescence phenomena. Materials and Methods: Among the identified proteins, we selected Filamin B (FLNB) and Aminopeptidase N (CD13) that were exclusively found in the secretome of senescent cells. We silenced their mRNA expression in BM-MSCs by means of RNA interference technology and induced acute senescence by hydrogen peroxide treatment. Our goal was to evaluate if FLNB or CD13 silencing may affect onset of senescence. Results: Our preliminary data showed that CD13 protein could be a key factor involved in the regulation and determination of both primary and paracrine induced senescence in human BM-MSCs. On the other hand, Filamin B seems not to be involved in the determination of primary senescence whereas its presence could be part of the mechanism that regulates the senescence induction in human BM-MSCs by paracrine signaling. Conclusion: Our study provides a useful base for identifying the complex extracellular protein networks involved in the regulation of MSC cellular senescence.