Session Time: 3:15pm-4:45pm
Presentation Time: 3:51pm-4:03pm
*Purpose: EVs (Extracellular vesicles), circulating microparticles able to mediate cell-to cell communication, are emerging as pivotal in different kidney diseases. Renal Antibody-Mediated Rejection (AMR) is characterized by endothelial to mesenchymal transition (EndMT) and accelerated senescence in tubular epithelial cells (RPTEC). However, the potential role of EVs in accelerating renal aging and early fibrosis after AMR is not well understood.
*Methods: Renal biopsies and serum purified EVs from 10 Acute and Chronic AMR patients were collected. Inflammaging (p16INK4a) and EndMT markers (CD31/αSMA) were evaluated by IHC and IF. EVs were isolated by ultracentrifugation and characterized by Nanoparticle Tracking Analysis (Nanosight, NTA EV/ml) and FACS (Attune Nxt). RPTEC and Eahy926 culture were incubated with EVs (5e+4 EVs/cells target for 24h); then to assess EndMT we performed FACS. Cellular senescence was investigated by qPCR for p21, p53, Klotho and CYP1B1 and SA-β-gal staining were performed. mRNA level of C3 and CFH were also measured.
*Results: Renal AMR biopsies showed significant tubular senescence as indicated by p16 expression; p16 was significantly upregulated in Chronic compared with Acute AMR biopsies (p<0.05). The AMR biopsies showed positivity for EndMT, as indicated by CD31 decrease and interstitial αSMA upregulation (p<0.05). In AMR patients sera, EVs appeared to be significantly augmented in acute AMR compared to healthy serum controls, in a higher manner than chronic AMR (NTA, p=0.0154)[RF1] . In vitro, the exposure of RTEC to AMR-derived EVs induced senescence as observed by significant increase in SA-β-gal+ cells and p21, p53, CYP1B1 gene expression (p<0.05). Furthermore, AMR derived EVs induced Klotho gene expression downregulation compared to basal RPTEC culture. In accordance, the AMR derived EVs induced the EndMT as observed by FACS with the downregulation of CD31, VE-cadherin (CD144) and increase of Vimentin and Collagen I (p=0.025). Finally, EVs from AMR patients induced a significant increase in C3 gene expression with concomitant downregulation in CFH in RPTEC. [RF1]Ho chiesto al gruppo di Cantaluppi il valore NTA EV/ML DELLE EV dei tx controllo
*Conclusions: These results suggest a putative role for circulating AMR derived-EVs in inducing the tubular inflammaging by local complement activation and early fibrosis by EndMT. The EVs cargo characterization might highlight novel targets for therapeutic intervention.
To cite this abstract in AMA style:Castellano G, Franzin R, Stasi A, Divella C, Merlotti G, Quaglia M, Sallustio F, Stallone G, Cantaluppi V, Gesualdo L. Extracellular Vesicles Mediate Endothelial to Mesenchymal Transition and Tubular Senescence in Renal Antibody- Mediated Rejection by Inducing Complement Activation [abstract]. Am J Transplant. 2020; 20 (suppl 3). https://atcmeetingabstracts.com/abstract/extracellular-vesicles-mediate-endothelial-to-mesenchymal-transition-and-tubular-senescence-in-renal-antibody-mediated-rejection-by-inducing-complement-activation/. Accessed June 12, 2021.
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