Bone Marrow-Derived Mesenchymal Stem Cell Secretome Alters Gene Expression and Upregulates Motility of Human Endometrial Stromal Cells

Cyclic regeneration of the endometrium, and its repair after parturition or injury, are crucial for successful reproduction. Mesenchymal stem cells (MSCs) derived from bone marrow (BM-MSC) facilitate tissue repair via their secretome, which contains growth factors and cytokines that promote wound healing. Despite the implication of MSCs in endometrial regeneration and repair, the mechanisms remain unclear. This study tested the hypothesis that the secretome of MSCs from human BM upregulates human endometrial stromal cell (HESC) proliferation, migration and invasion, and activates pathways to increase HESC motility. MSCs were purchased from ATCC (BM-MSC-1) and cultured from the BM aspirate of a healthy female donor (BM-MSC-2). Indirect co-culture of MSCs and hTERT-immortalized HESCs via a transwell system studied the effect of the BM-MSC secretome on HESC proliferation, migration, and invasion. To study the effect of the MSC secretome on HESC gene expression, HESCs were exposed to the BM-MSC secretome via indirect co-culture for 24 h. Total RNA was extracted from HESCs for RNA sequencing (RNA-Seq). Differentially expressed genes (DEG) and significantly altered pathways were identified. Indirect co-culture of HESCs with BM- MSCs resulted in significant increase in HESC migration and invasion regardless of the source of MSCs. Effects on cellular proliferation varied among the BM-MSC source. Exposure of HESCs to the secretome of BM-MSCs changed the expression of 10,141 genes with FDR < 0.05. There was overlap among 4351 genes between HESCs exposed to BM-MSC-1 and BM-MSC-2, including upregulated expression of cell motility genes common to both BM-MSC exposures. Increased HESC motility by the secretome of BM-MSC appears to be mediated by paracrine and autocrine mechanisms, in part by modifying HESC gene expression. These data support the potential for leveraging the MSC secretome as a novel cell-free therapy in the treatment of disorders of endometrial regeneration. 9 hTERT-immortalized human endometrial stromal cell (HESC) samples were analyzed; n=3 replicate samples for HESC exposed to BM-MSC purchased from ATCC (BM-MSC-1) (HESC+BM-MSC-1-1, HESC+BM-MSC-1-2, HESC+BM-MSC-1-3), n=3 replicate samples for HESC exposed to BM-MSC isolated from healthy female donor BM (BM-MSC-2) (HESC+BM-MSC-2-1, HESC+BM-MSC-2-2, HESC+BM-MSC-2-3), and n=3 replicate samples for the control group exposed to control media without MSCs (HESC-1, HESC-2, HESC-3).