(W1047) DYSREGULATED MICRORNAS IN THE EXTRACELLULAR VESICLES DERIVED FROM BONE MARROW MESENCHYMAL STROMAL CELLS OF ACQUIRED APLASTIC ANEMIA PATIENTS ARE INVOLVED IN HEMATOPOIETIC DYSFUNCTION
PhD Student Sanjay Gandhi Post Graduate Institute of Medical Sciences Lucknow, Uttar Pradesh, India
Abstract: Extracellular Vesicles (EVs) derived from bone marrow mesenchymal stromal cells (BM-MSC) play an essential role in determining the fate of hematopoietic stem and progenitor cells (HSPC) in the BM niche. Acquired aplastic anemia (AA) is a state of bone marrow failure characterized by multilineage cytopenia’s and hypoplastic marrow due to destruction of HSPC. We have previously reported that EVs from BM-MSC of AA patients delimits the proliferative and colony-forming capacity and elevates apoptosis of HSPC. Further, these EVs serve as cargo for microRNAs (miRs) in a tightly regulated manner and can potentially alter the phenotype of the recipient cell. Thus, we hypothesized that miRs enriched in AA BM-MSC EVs may be contributing towards hematopoietic dysfunction. Therefore, our aim was to identify differentially expressed (DE) miRs in AA BM-MSC, their target HSPC genes, and target pathways in AA BM-MSC EVs. We also delineated that inhibition of miR-139-5p in AA BM-MSC has therapeutic implications. To conduct the study, RNA was isolated from BM-MSC EVs of AA (n=4) and NC (n=6) and HSPC dataset was obtained from GEO database. DESeq and miRNet were used to identify DE miRs, HSPC, and miR target genes. KEGG database embedded in miRNet was used for Pathway analysis and Cytoscape was used to visualize hub HSPC genes. miR-139-5p was inhibited in AA BM-MSC using miRVana inhibitor, and its role in regulating HSPC functions was evaluated. This study was approved by IEC and IC-SCR of the Institute. Our results revealed that EVs from AA BM-MSC had 34 DE mature miRs, targeting 235 HSPC genes in AA patients (>log2fold). Network and Hub-gene analysis revealed interaction between significantly altered miRs with top 10 hub HSPC genes (IGF-1R, PAK1, APP, IGF-2R etc) which had enrichment of chemokine, MAPK, NK cell-mediated cytotoxicity, Rap1, PI3k-Akt, mTOR signalling pathways, associated with hematopoietic homeostasis. We further demonstrated that inhibition of miR-139-5p in AA BM-MSC was able to restore the proliferation, inhibited the apoptosis of co-cultured HSPC, and increased expression of IGF-1R significantly. Our data highlights that miRs from EVs of AA BM-MSC are significantly dysregulated and are involved in hematopoietic dysfunction. Future studies are warranted to elucidate the therapeutic potential of these EV miRs in AA.
Funding Source: Soniya Nityanand and Chandra P Chaturvedi- DBT Extramural grant (BT/PR31421/MED/31/407/2019), the Department of Biotechnology (DBT), New Delhi, Jyotika Srivastava- DST INSPIRE Fellowship (IF170881),New Delhi.
