The Effect Of High Salt On Proliferation Of Hematopoietic Stem Cells In Mice And Preliminary Study On Its Molecular Mechanism

Background and Objective:Hematopoietic stem cells(HSCs)are the basis of the hematopoietic system of adult mammals.These rare cells are characterized by their ability to self-renew and differentiate,thereby maintaining their numbers and differentiating into all lineages of the blood and immune system.HSCs reside in the bone marrow(BM)of adult mammals and produces immature progenitor cells.That produce mature cells through a series of proliferation and differentiation processes,further differentiate?mature cells,including red blood cells(RBC),megakaryocytes(MEC),myeloid cells and lymphocytes.HSCs?that had strict?regulation of?self-renewal and differentiation ensure an?appropriate?balance of blood cell production throughout life.Sodium is an essential nutrient for living things.The proper amount of sodium in the body is essential for maintaining the body's osmotic pressure,body fluid distribution,normal pH and most metabolic processes.The influx of sodium ions across the plasma membrane is necessary for action potentials,which are the basis of nerve impulses and muscle contractions.Too low sodium is not enough to maintain these important functions.The main source of human sodium is daily dietary salt.According to the previous reports,NaCl can promote?the proliferation of cardiomyocytes,kidney cells,and T-helper lymphocytes,but the effect on the hematopoietic cells proliferation has not been reported.In this study,we found that the appropriate increase of NaCl concentration can promote the proliferation of murine HSCs?under the conventional culture condition.?The proliferative level?of HSCs was the highest in mice fed?with?high-salt diet for 15 days,and the?linage differentiation?of HSCs?was not affected in the short term.?We further confirmed that high salt may promote the proliferation of HSCs by activating?PI3K/SGK1/GSK3? signaling pathway?using inhibitor GSK650394,Amiloride and SP600125 treatment and Western blot.?Our results indicated that high salt can promote the proliferation of mouse HSCs in vitro?independent of?osmotic pressure and Cl~-.In vivo?experimental results?confirmed that high salt diet?in a short period of time can increase the number of murine?HSCs rapidly.Using molecular biology and flow cytometry methods,we preliminary found that NaCl might?promote the proliferation of HSCs by activating PI3K/SGK1/GSK3? signaling pathway.These results provide a novel direction?for studies?of hematopoietic recovery.Methods:1.Using mouse bone marrow cells as the research object,the proliferation of HSCs?was detected by?flow cytometry?and?clone formation?assay;2.Mice were fed?with?high salt,and the proliferation and?linage?differentiation of HSCs?in bone marrow and spleen were detected by flow cytometry;3.To test whether SGK1 promotes?the proliferation of HSCs?by constructing SGK1 mutants,packaging retrovirus,infecting CD117~+?cells and detecting GFP~+?cells;4.To verify whether SGK1 can promote the proliferation of HSCs?by inhibiting?SGK1 activity in vitro and in vivo with?chemical inhibitors;5.To detect?the related signal pathways by flow cytometry and Western blot.Result:1.High salt promotes the proliferation of mouse hematopoietic stem cells(HSCs)in vitro;2.High salt promotes the proliferation of HSCs regardless of osmotic pressure;3.High salt promotes the proliferation of HSCs in the body;4.NaCl promotes the proliferation of HSCs through the PI3K/SGK1/GSK3? pathway.Conclusion:Through analysis of the experimental results,we found that high salt can promote the proliferation of mouse HSCs in vitro,and has nothing to do with osmotic pressure and Cl~-,and in vivo experiments have confirmed that feeding high salt feed in a short period of time can increase the number of mouse HSCs rapidly.It has been initially confirmed that NaCl may promote the proliferation of HSCs by activating the PI3K/SGK1/GSK3? signaling pathway.These results provide new ideas for the research of hematopoietic recovery.