Immunosuppressive Effects of Human Chorionic Gonadotropin (hCG) on Mesenchymal Stromal Cells

Mesenchymal stem/stromal cells (MSCs) as one of the most important types of adult stem cells secrete a variety of immunomodulatory cytokines. However, their immunomodulatory features strongly depend on the molecular cross-talk between cells and the surrounding microenvironment. Hence, some strategies were proposed to empower their beneficial effects during cell-therapeutic procedures to avoid confusing results. Licensing the cells with chemical compounds could be considered as one of the most applicable methods for induction of anti-inflammatory status in the cells. Human chorionic gonadotropin (hCG) is a pregnancy related hormone which has been shown to be essential for the establishment of a successful pregnancy. HCG supports the implantation of fetus in the maternal endometrium, due to its immunomodulatory effects. Moreover, the regulatory role of hCG has been previously mentioned in case of some autoimmune-based diseases. In the present study, the capacity of this hormone for induction of different immuneencountered genes expression was examined in primary cultures of human adipose tissue derived mesenchymal stem cells (Ad-MSCs). In this regard, Ad-MSCs were exposed to 10 IU of hCG for 72 hours. Molecular studies via quantitative Real-time PCR (qRT-PCR) experiments were performed to detect gene expression modifications based on the application of SYBR Green as the fluorescent dye and in comparison to the RPLP0 as the housekeeping gene. Results confirmed that hCG significantly upregulated TSG-6, TGF-β1, IL-1β and IL-6 expression levels comparing with the control group, while it downregulates COX-2 expression, and had no statistically significant effects on IL-10 and TDO2. In conclusion, priming Ad-MSCs with hCG may enhance the proliferation and immunoregulatory potential of these cells, although it needs further investigations to reveal involved molecular pathways.