Regulatory Effect Of MiR-140-5P In Osteogenesis And Adipogenesis Of BMSCs Under Stress

Intention:Objective one,to look into the changes in the expression level of miR-140-5P during osteogenic and adipogenic differentiation of rat bone marrow stem cells under stress.Objective two,to investigate the effect of miR-140-5P on osteogenic and adipogenic differentiation of rat bone marrow stem cells under stress.Objective three,to probe into the joint effect of cellular stress and miR-140-5P on differentiation of rat bone marrow stem cells through TGFβ1/Smad2 signaling pathway.Methods:Step one,osteogenic and adipogenic differentiation of rat bone marrow stem cells in vitro was induced in groups,with the experimental groups loaded with appropriate cellular stress;the expression level of bone markers composed of osteogenic differentiation and lipid markers composed of adipogenic differentiation were detected after induction for a certain period oftime and in the meantime the expression level of "miR-140-5P" in different groups at different periods was checked,clarifying that different differentiation directions of BMSCs would bring about variation in the expression level of "miR-140-5P".Step two,an over-expression model and a low-expression model of miR-140-5P were constructed,with stress continuing to be exerted on the experimental groups;osteogenic and adipogenic differentiation was induced in groups;during and after induction,PCR and WB were used respectively to check out the expression level of osteogenic differentiation markers and adipogenic differentiation markers in the over-expression and low-expression models of miR-140-5P,clarifying the effect of miR-140-5P on BMSCs differentiation.Step three,the over-expression and low-expression models of miR-140-5P were cross-paired with the stress group and the stress-free group;the effect of miR-140-5P and cellular stress on TGF(3 1/Smad2 signaling pathway was checked.Results:In step one,the induced osteogenic differentiation group in the experimental groups showed the highest expression level of osteogenic and pathway markers,while the stress-free induced adipogenic differentiation group exhibited the highest expression level of adipogenesis marker,followed by the induced adipogenic differentiation group in the experimental groups.The highest expression level of miR-140-5P was found in the induced adipogenic differentiation group among the control groups and the induced adipogenic differentiation group among the experimental groups.In step two,the miR-140-5P low expression model group had the highest expression level of osteogenic markers among the experimental groups,while,in the control groups,the miR-140-5P over-expression model had the highest expression level of adipogenesis markers in the control groups.Step three indicated that miR-140-5P could inhibit the TGFβ1/Smad2 signaling pathway by down-regulating TGFβR1 and that cell stress could up-regulate the TGFβ1/Smad2 signaling pathway by up-regulating TGFβ1.Conclusion:Distraction stress can promote osteogenic differentiation of bone marrow stem cells while inhibiting adipogenic differentiation.MiR-140-5P is in low expression during osteogenic differentiation and high expression during adipogenic differentiation.High-expressed miR-140-5P can facilitate adipogenic differentiation of bone marrow stem cells,whereas low-expressed miR-140-5P can promote the osteogenic differentiation of bone marrow stem cells.Cellular stress is mutually antagonistic to miR-140-5P in terms of their regulating effects on rat bone marrow stem cell differentiation.