Inactivation of glycogen synthase kinase-3β up-regulates β-catenin and promotes chondrogenesis

Abstract

This study aimed to investigate whether inhibition of glycogen synthase kinase-3β (GSK-3β) could promote chondrocytes proliferation. The expression pattern of GSK-3β was firstly determined by immunohistochemistry (IHC) in normal mouse. Tibias were then isolated and cultured for 6 days. The tibias were treated with dimethylsulfoxide (control) or GSK-3 inhibitor SB415286 (SB86). Length of tibias was measured until 6 days after treatment. These bones were either stained with alcian blue/alizarin red or analyzed by IHC. In addition, GSK-3β and β-catenin were analyzed by Western blot. Finally, cartilage-specific GSK-3β deletion mice (KO) were generated. Efficiency of GSK-3β deletion was determined through Western blot and IHC. After treated by inhibitor SB86, the overall length of growth plate was not changed. However, growth of tibia in SB86 group was increased by 31 %, the length of resting and proliferating was increased 13 % (P < 0.01), whereas the length of hypertrophic was decreased by 57 % (P < 0.01). Besides, the mineralized length was found to be significant longer than the control group (P < 0.05). In KO mice, growth plate and calvaria tissue both exhibit significant reduction of GSK-3β (P < 0.05) whereas the lengths of tibias in KO were almost same compared with control mice. Finally, an increase amount of β-catenin protein was observed in SB86 (P < 0.05). In addition, significantly increased β-catenin was also found in the growth plate of KO mice (P < 0.05). Inhibition of GSK-3 could promote longitudinal growth of bone through increasing bone formation. Besides, the inactivation of GSK-3β could lead to enhancing β-catenin, therefore promote chondrocytes proliferation.

Phosphoproteomics of Fibroblast Growth Factor 1 (FGF1) Signaling in Chondrocytes: Identifying the Signature of Inhibitory Response

“…Our experiments are in line with ex vivo data published by Dr. Beier's group (55) where prolong GSK3␤ inhibition in a metatarsal organ culture system caused increased longitudinal growth of endochondral bones mimicking the phenotype of FGFR3 knockout mice (56,57). Similar effect on the tibia length was reported in cartilage-specific GSK3␤ KO mice (58). At this point it is not clear why Kapadia et al (59) had an opposite result showing that a different pharmacological inhibitor reduced chondrocyte proliferation in a metatarsal organ culture model.…”

Calvarial Suture-Derived Stem Cells and Their Contribution to Cranial Bone Repair

“…Gli1 + cells are also clonogenic in vitro and subcultured clones were successfully differentiated into osteo-, chondro-, and adipogenic lineages under appropriate conditions (Zhao et al, 2015 ). With the exception of the recently reported Leptin receptor (Zhou et al, 2014 ), none of the bone marrow SSC markers investigated by Maruyama was distinctively expressed in the Axin2 + cells of the suture ( Mcam/CD146, Nestin and Gremlin1 ). Moreover, the in vitro differentiation ability of these cells was not assessed in this particular study.…”

“…However, the membrane has been suggested to regulate osteogenesis via paracrine signaling (Cadet et al, 2003 ) and to provide osteoprogenitors that support craniofacial repair (Ochareon and Herring, 2011 ). Unlike the thoroughly described bone marrow-residing SSCs as the main source of osteoprogenitors during long bone repair (Zhou et al, 2014 ), the contribution of calvarial specific stem cells for cranial regeneration was unknown until very recently. Although a clonal population with multipotent MSC differentiation properties has long been isolated from rat calvaria (Grigoriadis et al, 1988 ), the visual evidence of the niche where the calvarial SSCs reside was only provided in the last few years.…”

GSK-3β as a target for protection against transient cerebral ischemia

“…While suppressing the expression of GSK-3β, TWS119 inhibited phosphorylation of β-catenin and increased its total protein expression38. β-catenin is a key component for activating the Wnt/β-catenin pathway39, and phosphorylation at Ser552 has been shown to induce beta-catenin accumulation in the nucleus and increases its transcriptional activity.…”