Monophosphoryl Lipid A and Retinoic Acid Combinations Increased Germ Cell Differentiation Markers Expression in Human Umbilical Cord-derived Mesenchymal Stromal Cells in an In vitro Ovine Acellular Testis Scaffold

Infertility is known as one of the most common problems among couples. In this regard, generation of male germ cells from adult stem ones are among the current promising priorities of researchers. Mesenchymal stromal cells (MSCs) were previously induced to differentiate into germ-like progenitors in vitro. Monophosphoryl lipid A (MPLA) is a detoxified derivative of lipopolysaccharides (LPS) that lacks many of the endotoxic properties of LPS. Our present study aimed to investigate the expression of migration genes (CXCR4, VCAM1, VEGF, MMP2, and VLA4), and differentiation markers during human umbilical mesenchymal stromal cells (hUMSCs) culture in the presence of retinoic acid (RA) and MPLA-treated acellular testis. Accordingly, the high expression levels of deleted in azoospermia-like (DAZL), piwi-like RNA-mediated gene silencing 2 (PIWIL2) transcripts as well as protein were consequently observed in treated hUMSCs. It was concluded that combination treatment (i.e., MPLA/RA) had more prominent results than each of the treatments alone, even though MPLA and RA could be regarded as inducer of migration and differentiation, respectively. Ultimately, it was suggested to introduce the use of combination treatment as a more effective strategy to improve therapies in regenerative medicine.