Unconjugated
PURPOSE:
Kashin-Beck disease (KBD) is an endemic degenerative osteoarthritis associated with extracellular matrix degradation. The aim of this investigation was to evaluate the role of targeting genes in the pathogenesis of KBD and primary osteoarthritis (OA) involved in extracellular matrix degradation.
METHODS:
Agilent 44 K human whole-genome oligonucleotide microarrays were used to detect the gene expression in KBD and OA cartilage. The mRNA and protein expressions of CSGalNAcT-1 and Hapln-1 in chondrocytes were verified by reverse transcription polymerase chain reaction (RT-PCR) and western blot, and their expression in cartilage were verified with immunocytochemical analysis. Meanwhile, CSGalNAcT-1 and Hapln-1 protein levels in the selenium intervention group of KBD with different concentrations (0.25, 0.1 and 0.05 μg/ml) were detected by western blot.
RESULTS:
CSGalNAcT-1 and Hapln-1 were down-regulated in KBD and OA at both mRNA and protein levels, and were increased in Se(Selenium) groups compared to KBD free-Se group. However, Wnt 3a, β-catenin and Runx-2 were up-regulated in OA and KBD at protein levels. Additionally, immunohistochemical staining showed that CSGalNAcT-1 and Hapln-1 were reduced in all zones of KBD and OA articular cartilage, but not significantly reduced in the up zone of OA articular cartilage.
CONCLUSIONS:
The CSGalNAcT-1 and Hapln-1 were down-regulated in both KBD and OA cartilage. CSGalNAcT-1 may be involved in the damage of articular cartilage of KBD and OA by regulating Hapln-1 in the Wnt/β-catenin signalling pathway. It was indicated that CSGalNAcT-1 and Hapln-1 may play important roles in the pathogenesis of KBD and OA.
Osteogenesis disorder is involved in osteoporosis and other related bone diseases, in which osteogenic differentiation is essential. Osteogenic differentiation is a complicated process regulated by intricate signal transduction networks. It has been reported that low-power laser irradiation (LPLI) has an osteogenic potential by promoting osteoblast differentiation. However, the molecular mechanisms remain to be understood. In this study, we reveal a novel mechanism that Akt/GSK3β/TAZ (transcriptional co-activator with PDZ-binding motif) signaling pathway plays a crucial role in LPLI-enhanced osteoblast differentiation. Photomodulation by LPLI activated Akt/GSK3β pathway which inhibited TAZ phosphorylation, leading to the increase of TAZ protein level and nuclear aggregation. Meanwhile, knockdown of TAZ suppressed osteogenic differentiation promoted by LPLI. Further study showed that LPLI promoted the interaction between TAZ and core-binding factor 1 (Cbfa1), up-regulating the transcription of osteopontin (OPN) and osteocalcin (OCN) and the activity of alkaline phosphatase (ALP). However, inhibition of Akt/GSK3β pathway reversed the effects of TAZ on osteogenic differentiation induced by LPLI. Taken together, for the first time, we report that LPLI promotes osteoblast differentiation via TAZ activation dependent on Akt/GSK3β signaling pathway.