GPR39 agonist TC-G 1008 promotes osteoblast differentiation and mineralization in MC3T3-E1 cells.

Osteoporosis-related bone fracture and falls have a severe impact on patients' daily lives. Osteoblasts are bone-building cells that play a vital role in bone formation and remodeling. Imbalanced osteoblast differentiation could lead to osteoporosis. GPR39 is an orphan G protein-coupled receptor that mediates metabolic pathways. In this study, we show that GPR39 is expressed in MC3T3-E1 cells. Osteoblast differentiation culture media induces GPR39, suggesting that GPR39 is a differentiation-responsive factor. Activation of GPR39 using its selective agonist TC-G 1008 induces alkaline phosphatase (ALP), osteocalcin (OCN), and type I collagen (Col-I) expression, and increases cellular ALP activity and calcium deposition, implying that GPR activation promotes cells toward osteoblast differentiation. Treatment with TC-G 1008 also increases Runx-2 expression and AMPK activation. However, the inhibition of AMPK by Compound C abolished TC-G 1008-mediated ALP, OCN, and Col-I induction, and reduces ALP activity and cellular calcium deposition as well as Runx-2 induction. These data indicate that TC-G 1008-mediated GPR39 activation involves AMPK-mediated Runx-2 induction. In summary, our study uncovers a new role of GPR39 activation in osteoblast differentiation, implying that GPR39 could be a promising therapeutic target for osteoporosis.

miR-486-5p Inhibits Inflammatory Response, Matrix Degradation and Apoptosis of Nucleus Pulposus Cells through Directly Targeting FOXO1 in Intervertebral Disc Degeneration.

BACKGROUND/AIMS: microRNA-486-5p (miR-486-5p) and forkhead box protein O1 (FOXO1) play an important role in the development of intervertebral disc degeneration (IDD). However, their molecular mechanisms in IDD remain unknown. METHODS: qRT-PCR assay was used to identify miR-486-5p expression in nucleus pulposus (NP) cells. In-vitro transfection, CCK-8, flow cytometry and luciferase reporter assay were used to validate the role and relationship of miR-486-5p and FOXO1 in lipopolysaccharides (LPS)-stimulated NP cells. qRT-PCR and Western blot were used to measure the expression levels of inflammatory cytokines, matrix degrading enzymes, and extracellular matrix (ECM)-related genes. RESULTS: miR-486-5p expression was significantly down-regulated, while FOXO1 expression was up-regulated in LPS-treated NP cells (P<0.001). miR-486-5p over-expression repressed LPS-induced expressions of inflammatory cytokines (IL-1ß, IL-6 and TNF-α) and matrix degrading enzymes (MMP-3, MMP-13, ADAMTS-4 and ADAMTS-5), and promoted the expressions of LPS-inhibited ECM-related genes (Aggrecan and Collagen II) (all P<0.001). In addition, miR-486-5p over-expression protected NP cells against LPS-induced apoptosis. However, inhibition of miR-486-5p led to the opposite effects. Mechanically, FOXO1 was a direct target gene of miR-486-5p. Over-expressed FOXO1 aggravated LPS-induced injury, and antagonized protection effects of miR-486-5p. CONCLUSION: miR-486-5p can inhibit inflammatory response, ECM degradation and apoptosis in NP cells by directly targeting FOXO1, which may contribute to the biological therapy of IDD.

Expression of long non­coding RNAs in chondrocytes from proximal interphalangeal joints.

Osteoarthritis (OA) of hand is a common disease, resulting in disability of the hands. The pathogenesis of hand (H) OA remains to be elucidated, and findings from knee and hip joints cannot be simply applied to HOA. To improve knowledge on the specific biology and pathobiology of HOA, the present study performed bioinformatics analyses to analyze the long non­coding (lnc) RNA expression profile in human chondrocytes of proximal interphalangeal (PIP) finger joints and knee joints. Gene expression data were downloaded from the Gene Expression Omnibus database, and PIP and knee chondrocytes were analyzed (n=3/group). Probes of the Affymetrix Human Gene 2.0 ST Microarray were annotated to obtain information about lncRNA expression profile. Compared with chondrocytes from knee joints, chondrocytes derived from PIP joints had significantly different lncRNA expression profiles, and 1,172 lncRNAs were differentially expressed. Compared with chondrocyte from knee joints, 534 lncRNAs were upregulated and 638 lncRNAs were downregulated in chondrocytes from PIP joints. A co­expression network was constructed to analyze the correlation between lncRNAs and protein­coding genes. Function annotation analyses suggested that protein­coding genes that are co­expressed with lncRNAs are enriched in the biological processes of bone morphogenesis, bone development and cartilage development. In conclusion, the present study demonstrated that chondrocytes derived from PIP joints exhibit a significant difference in lncRNA expression compared with chondrocytes derived from knee joints.

Combined anteversion technique in total hip arthroplasty for Crowe IV developmental dysplasia of the hip.

BACKGROUND: A high rate of postoperative dislocation in total hip arthroplasty (THA) for Crowe IV developmental dysplasia of the hip (DDH) has been reported, 1 of the main reasons being higher true acetabular anteversion. If the cup is fixed with normal anteversion, the anterior rim will be excessively exposed, which reduces the contact areas of the cup and bone, affects prosthesis stability, and leads to iliopsoas tendinitis and persistent hip pain after THA. The aim of this study was to demonstrate that when cup anteversion is larger, adjusting femoral anteversion to bring the combined anteversion (CA) into the "safe zone" might prevent dislocation. METHODS: After having fixed the cup in the acetabulum according to the patients' native acetabular anteversion, we shortened and rotated the proximal femur to reduce femoral anteversion, adjusting the CA into the "safe zone". The Harris Hip Score (HHS) was used to evaluate hip joint function. Computerised tomography scanning was used to measure the anteversion angles. RESULTS: All patients were followed up without any dislocation. Preoperative and 12 months after surgery, the mean HHS were 43.3 ± 2.6 (38-47) and 88.1 ± 3.3 (78-92) respectively. Pre- and post-operation, the mean CA angles were 88.6° ± 9.4° (80.3°-119.4°) and 49.2° ± 2.6° (43.4°-54.4°) respectively. The bone healing time of femoral osteotomy ranged from 4 to 14 months, with a mean time of 7.5 months. CONCLUSIONS: This CA technique in THA for Crowe IV DDH can effectively prevent postoperative dislocation and provide good hip function.