ABSTRACT: Acquired aplastic anemia (AA) is a rare disorder characterized by bone marrow (BM) failure, marked by a severe reduction in hematopoietic stem and progenitor cells (HSC/HPC) and BM microenvironment disruption, including BM replacement by adipocytes. While cytotoxic T-cell-mediated destruction of HSC/HPC is a key factor in AA pathogenesis, alterations in the stem cell niche are also implicated. Studies have reported dysfunctional mesenchymal stromal cells (MSCs) within the BM, although findings have been inconsistent. In this study, we performed bulk mRNA sequencing of BM-derived MSCs from patients with acquired idiopathic severe AA (SAA) and healthy controls to identify genes associated with disease pathophysiology and potential therapeutic targets. Using adjusted p-values (padj) < 0.05 and log2 fold-change (L2FC) cutoffs of <-1.5 for downregulated and >1.5 for upregulated genes in AA, we identified 306 differentially expressed genes (DEGs): 188 downregulated and 118 upregulated. Molecular patterns associated with altered immune response, adipogenesis, lipid metabolism, osteoblast differentiation, osteoclast activity, extracellular matrix (ECM) remodeling, cell interaction, hematopoietic support, angiogenesis, DNA repair/damage response, and stress response were observed in AA-derived MSCs compared to controls. Furthermore, gene expression profiles related to Wnt/β-catenin, MAPK, PI3K/AKT, JAK/STAT, and NF-κB signaling pathways were identified, although with variable results. This study seeks to provide new insights into the altered BM microenvironment in AA, advancing our understanding of disease mechanisms and facilitating the development of novel therapeutic strategies.
