Effect Of Acidic Condition On Human Umbilicail Cord Mesenchymail Stem Cells

Mesenchymal Stem Cells (MSCs), a kind of adult stem cells, which have self-renewal and multipotent differentiation functions, become well-known due to differentiating into the mesenchymal tissue. Under a specific internal and external environment, MSCs can be induced the differentiation and become various histiocytes. Human Umbilical Cord Mesenchymal Stem Cells (HUMSCs) are derived from Warton’s jelly of newborn umbilical cord, which has many advantages, including easily sampling, wide range of sources, not limited by ethic restriction, low immunogenicity, highly in vitro proliferation, etc. Therefore, as the seed cells in the cell therapy, HUMSCs have become the research highlights among regenerative medicine, cell transplantation and cancer therapies. Studies showed that the lactic acid accumulation was caused by hypoxia-induced anaerobic glycolysis under the ischemia and inflammation, such as respiratory allergic asthma, rheumatoid arthritis, atherosclerosis, tumor microenvironment and so forth and then, resulting in acidification of extracelluar environment which went against the normal cell survival. However, the mechanism of HUMSCs acting as seed cells used in cell therapies has not reported yet. This study has selected the HUMSCs as a cell model to simulate the pathological acid environment in vitro and investigate the impacts of acidic condition on HUMSCs’survival and transfer ability, as well as the cell response mechanism of HUMSCs under the acidic condition in a preliminary study.Methods:HUMSCs were obtained using the "round coverslip" method. Cell surface markers of HUMSCs were tested by flow cytometry (FCM). Expressions of four proton-sensing receptors (TDAG8, GPR4, OGR1 and G2A) of HUMSCs were tested by Real-time PCR while expressions of four proton perception receptors (TDAG8 GPR4,OGR1 and G2A) under an acidic condition stimulation also tested by Real-time PCR. Survival ability of HUMSCs under an acidic condition was tested by MTT method while the transfer ability of HUMSCs under an acidic condition was tested by Micro Chemotaxis Chamber.Results:HUMSCs were successfully obtained via isolation and culture using the "round coverslip" method. HUMSCs high expression of CD105, CD90, CD73 and CD29 and lower expression of CD45, CD34 and HLA-DR were tested by flow cytometry (FCM). Real Time PCR test revealed that the relative expression amount of GPR4 receptor in HUMSCs was significantly higher than that of a few other receptors (P<0.01), the expression amount of TDAG8 and OGR1 receptors in the next place, and G2A almost no expression. Real Time PCR discovered that TDAG8 was highly expressed at pH6.8. The test results of MTT method showed that the survival rate of HUMSCs had no significance at pH6.8, pH7.2 and pH7.6. Micro Chemotaxis Chambermethod detected that pH6.8 excited HUMSCs and accelerated the cell migration.Conclusion:Human Umbilical Cord Mesenchymal Stem Cells (HUMSCs) had overexpression of proton-sensing receptor TDAG8. HUMSCs can be survived under an acidic condition, namely HUMSCs may adapt to the acid environment. Meanwhile, the acid environment will excite and accelerate the migration of HUMSCs. This study has investigated and discussed the impacts of acidic condition on HUMSCs’ survival and migration, which will provide some basic theoretical evidence for further follow-up studies in HUMSCs acting as seed cells on mechanism of cell therapies.