Contribution of SATB2 to the stronger osteogenic potential of bone marrow stromal cells from craniofacial bones

Abstract

Previous studies have shown that craniofacial bone marrow stromal cells (BMSCs) have a strong osteogenic potential. However, the mechanism by which BMSCs of various embryonic origins develop diverse osteogenic potentials remains unclear. To investigate the mechanisms regulating osteoblast differentiation in two different types of BMSCs, we compared the temporal and spatial mRNA and protein expression patterns of Satb2 and its downstream gene Hoxa2 by using real-time polymerase chain reaction, Western blotting and fluorescent immunostaining in mandible BMSCs (M-BMSCs) and tibia BMSCs (T-BMSCs) undergoing osteoblast differentiation. Higher levels of alkaline phosphatase, greater calcium accumulation and earlier expression of Runx2 were observed in osteogenic-induced M-BMSCs compared with T-BMSCs. Low levels of Satb2 were detected in both types of uninduced BMSCs but the majority of SATB2 was located in the nuclei of M-BMSCs. Notably, Satb2 was expressed earlier in M-BMSCs and Hoxa2, a downstream target of Satb2, was not expressed in uninduced M-BMSCs or during osteoblast differentiation, just as during embryonic mandible development. In contrast, Hoxa2 was reactivated in T-BMSCs during osteoblast differentiation. Based on these results, we conclude that SATB2 plays a different role during osteoblast differentiation of M-BMSCs and T-BMSCs. The earlier activation of Satb2 expression in M-BMSCs compared with T-BMSCs might explain the stronger osteogenic potential of M-BMSCs.

SATB2-Nanog axis links age-related intrinsic changes of mesenchymal stem cells from craniofacial bone

“…Western blots and real-time PCR analysis were performed as our previous reports [ 43 ]. The primary antibodies used for western blots are listed in Supplementary Table S2 .…”

“…All procedures were carried out according to the guidelines of the Animal Care Committee of Nanjing Medical University. As we described previously [ 43 ], BMSCs derived from mandibular were isolated from young group (3 months old), middle-aged group (12 months old) and old group (18 months old) male Sprague-Dawley (SD) rats. 15 months old SD rats were transplanted with green fluorescent protein (GFP) modified or SATB2 enforced BMSCs (1 × 107) by tail vein at week 2, 6, and 12 after micro-CT scan.…”

Polyethylenimine600-β-cyclodextrin: a promising nanopolymer for nonviral gene delivery of primary mesenchymal stem cells

“…[18][19][20] Special AT-rich sequencebinding protein 2 (SATB2) is another factor responsible for osteoblast differentiation of BMSCs. 21 Overexpression of SATB2 promotes osteogenesis and improves bone mass in mice. 22 Genetically modified BMSCs are widely used in bone-tissue engineering.…”

Expression and localization of special AT-rich sequence binding protein 2 in murine molar development and the pulp-dentin complex of human healthy teeth and teeth with pulpitis

“…SATB2 is an important positive regulator in osteoblast differentiation, bone formation, and bone regeneration ( 17 , 18 ). It has previously been demonstrated that SATB2 was able to repair and regenerate calvarial defects ( 19 ). In addition, SATB2 has also been reported to be expressed in the cortex of the brain, breast tissues, spinal cord, kidneys, umbilical cord, leukocytes and the central nervous system ( 9 , 17 ), which suggests a distinct role of SATB2 in different tissues.…”