ABSTRACT
@#With the continuous development of maxillary sinus floor elevation technology, the osteogenesis mechanism of maxillary sinus floor elevation has always been a concern of scholars. The membrane of the maxillary sinus is an indispensable physiological structure in the process of space osteogenesis under the sinus floor after elevation of the sinus floor. In recent years, the role of the maxillary sinus floor mucosa in sinus floor space osteogenesis has been a research hotspot. Recent studies have found that the maxillary sinus floor membrane plays a role as a natural biological barrier membrane in the process of sinus floor space osteogenesis after maxillary sinus floor elevation; in addition, it has the ability to undergo osteogenesis. It has also been found that maxillary sinus membrane stem cells (MSMSCs) derived from the maxillary sinus floor membrane have characteristics of mesenchymal stem cells, which can differentiate into osteoblasts and participate in sinus floor space osteogenesis after maxillary sinus floor elevation. New studies have also found that small RNAs such as microRNAs, long noncoding RNAs and circular RNAs can regulate the osteogenic differentiation of MSMSCs, which may be important biological targets for promoting osteogenesis in the sinus floor space. In this paper, the relationship between the maxillary sinus floor mucosa and bone formation after maxillary sinus floor elevation, the barrier and osteogenic function of the maxillary sinus floor mucosa, the sources of osteoblasts involved in osteogenesis of the sinus floor space, and the molecular regulatory mechanisms of stem cells derived from maxillary sinus mucosa will be elucidated step by step.
ABSTRACT
Objective@#To investigate the role of the bone morphogenetic protein 2 (BMP2)⁃Smad1/5 and p38MAPK signaling pathways in the osteogenic differentiation of MSMSCs by insulin⁃like growth factor 1 (IGF1).@* Methods @#A re⁃ combinant adenovirus (RAD) and IGF1 expressing IGF1 gene were constructed. After osteogenic induction, qRT⁃PCR and Western blot were used to detect the phosphorylation level of Smad1/5 and the expression of the BMP⁃2 protein in the BMP⁃Smad signaling pathway; immunohistochemistry was used to observe the nuclear translocation of Smad1/5; qRT⁃PCR and Western blot were used to detect IGF with Noggin and SB203580, inhibitors of the p38MAPK signaling path⁃ way 1⁃mediated osteogenic differentiation of MSMSCs@* Results@#The recombinant IGF1 adenovirus was constructed suc⁃ cessfully. MSMSCs were cultured in inductive medium after infection with different concentrations of Ad⁃IGF1, and then, the protein levels of BMP2 and p⁃Smad1/5 increased. IGF1 can also induce nuclear translocation of Smad1/5. In addition, Noggin significantly reduced the phosphorylation level of Smad1/5 and the formation of mineralized nodules in the MSMSCs. The mRNA levels of Runx2, OPN and ALP also decreased. In contrast, SB203580 decreased neither the phosphorylation level of p38 nor the mRNA expression of Runx2, OPN and ALP in the Ad⁃IGF1 MSMSCs@* Conclu⁃sion@#IGF1 can promote the osteogenic differentiation of MSMSCs via the BMP2⁃Smad1/5 signaling pathway. In con⁃ trast, IGF1 may not promote the osteogenic differentiation of MSMSCs via the p38MAPK signaling pathway.
ABSTRACT
Objective@#To detect the expression level of miR-27a during the osteogenic differentiation of beagle maxillary sinus membrane stem cells (MSMSCs) and explore the role of miR-27a in the osteogenic differentiation of MSMSCs.@*Methods@#Beagle MSMSCs were cultured in vitro. The expression level of miR-27a was detected via RT-PCR after an osteogenic inductive culture was prepared. The mRNA expression levels of Runx2 and OPN were examined via RT-PCR, and the protein expression levels of Runx2 and OPN were examined via Western blot after the cells were transfected with pre-miR-27a or anti-miR-27a. Finally, osteoprogenitor cells transfected with pre-miR-27a were composited with Bio-Oss particles and subcutaneously implanted into nude mice to form ectopic bone formation models, and then the inhibition of bone formation from miR-27a was observed in vivo. @*Results@#The expression level of miR-27a in the beagle MSMSCs decreased after osteogenic inductive culturing. The relative miR-27a levels were significantly decreased at day 1 (t=3.795, P=0.023), day 3 (t=4.493, P=0.011), day 7 (t=11.591, P < 0.001), day 14 (t=12.542, P < 0.001), and day 21 (t=5.621, P=0.008) compared with day 0. In addition, the expression levels of Runx2 mRNA (t=4.923, P=0.007) and protein (t=4.425, P=0.008) were reduced after the cells were transfected with pre-miR-27a. The expression levels OPN mRNA (t=5.253, P=0.006) and protein (t=5.132, P=0.006) were also reduced. In contrast, the mRNA expression levels of Runx2 (t=3.925, P=0.013) and OPN (t=3.712, P=0.019) were increased after the cells were transfected with anti-miR-27a, and bone formation was observed after the subcutaneous implantation of beagle MSMSCs composited with Bio-Oss in nude mice. Nevertheless, ectopic bone formation was inhibited by pre-miR-27a-transfected beagle MSMSCs composited with Bio-Oss (t=7.219, P=0.0020). @* Conclusion @# MiR-27a negatively regulates the osteogenic differentiation of MSMSCs.