Study The Mechanism Of FSH? Enhances The Osteogenic Differeftiation Of Bone Marrow Mesenchymal Stem Cells Induced By BMP2

Objective:Postmenopausal osteoporosis(PMOP)increases the rate of fracture disability and mortality in menopausal women.There is growing evidence that PMOP is associated with follicle-stimulating hormone(FSH).Bone loss in women Before menopause and estrogen deficiency,an increase in follicle-stimulating hormone precedes a decrease in estrogen,which may be one of the causes of premenopausal bone loss.Cell studies have found that the FSH receptor(FSHR)is present on osteoclasts,osteoclast precursor cells,and mesenchymal stem cells,but not on osteoblasts.FSH promotes osteoclast differentiation,activity and survival,but has little effect on osteoblasts and is not well defined for osteogenesis differentiation of mesenchymal stem cells.There is evidence that BMP(Bone morphogenetic protein)is involved in oocyte empowerment,primitive pool assembly,and primitive follicle activation.BMP,including BMP2,has been shown to participate in the regulation of FSH synthesis through a competitive binding mechanism,activate BMP to increase FSH synthesis,inhibit BMP inhibit FSH synthesis.BMP is a multifunctional growth factor belonging to the transformational growth factor-?(TGF-?)superfamily.These proteins are essential in many developmental processes,including cardiac,neurogenesis,and bone formation.BMP2 was the first BMP to be identified and has been well studied in the BMP family.BMP2 plays an important role in embryonic development,as well as in bone remodeling and maintaining bone homeostasis in adulthood.Some of its specific functions include finger formation and activation of osteogenetic genes such as runt-associated transcription factor 2(Runx2).Due to its multiple functions and osteogenetic potential,the U.S.Food and Drug Administration(FDA)approved the use of recombinant human BMP2(rhBMP2)in spinal fusion surgery,tibia repair,and maxillary sinus reconstruction surgery.Since the clinical application of BMP2 mainly involves bone,BMP2 is widely used in the clinical treatment of bone disjoint,spinal fusion,etc.,however,shortly after the initial injection of rhBMP2,there are some adverse complications reported,and alternative therapies have been developed to limit these side effects.However,it has not been used to promote bone drugs for the treatment of postmenopausal osteoporosis.Therefore,this study aims to explore the role and possible mechanism of FSH?in BMP2 in promoting the osteogenic differentiation of bone marrow stromal cells,and to provide new ideas for the research and development of osteogenesis drugs and the prevention and treatment of postmenopausal osteoporosis.Methods:1.Adenovirus BMP2(Ad-BMP2)and adenovirus FSH?(Ad-FSH?),infect ST2 cells,respectively.To investigate the effects of BMP2 and FSH? on the osteogenesis differentiation of bone marrow stromal cells,respectively.2.ST2 cells were co-infected with Ad-BMP2 and Ad-FSH? to investigate the effect of FSH? on the osteogenic differentiation of bone marrow stromal cells promoted by BMP2.3.The experiments were repeated in the medium containing Notch signaling inhibitor DAPT to explore whether Notch signaling mediated FSH? to enhance BMP2 and promote osteogenic differentiation of bone marrow stromal cells4.Osteogenic differentiation of bone marrow stromal cells was measured by ALP activity(ALP staining and biochemical quantification)and expression level of osteogenic marker genes(ALP?Osx?Runx2?Coll)Results:1.Bone marrow stromal cells were successfully infected with adenovirus Ad-BMP2/Ad-FSH? and overexpressed BMP2/FSH?,respectively.Overexpression of BMP2 significantly promoted the osteogenic differentiation of bone marrow stromal cells,while overexpression of FSH? did not.2.Bone marrow stromal cells infected with Ad-BMPP2 and Ad-FSH ? at the same time had better osteogenic differentiation than those infected with Ad-BMP23.FSH? enhanced Notch signaling during BMP2-induced bone marrow stromal cells osteogenic differentiation4.When Notch signaling inhibitor DAPT was added,BMP2 and FSH? had no significant difference in promoting bone differentiation compared with BMP2 aloneConclusion:FSH? did not promote osteogenic differentiation of bone marrow stromal cells by itself,but when combined with BMP2,FSH? significantly enhanced the osteogenic differentiation ability of BMP2 There was no significant difference in the osteogenic differentiation ability of bone marrow stromal cells after Notch signaling inhibition between FSH? and BMP2 alone,suggesting that FSH? may enhance the osteogenic differentiation ability of BMP2 by enhancing Notch signaling expression...