Background Long noncoding RNA (lncRNA) OIP5 antisense RNA 1 (OIP5-AS1) is an oncogenic lncRNA; however, its role in osteoarthritis (OA) pathology still remains unknown. Materials and Methods qRT-PCR was performed to measure the expressions of OIP5-AS1, miR-29b-3p and progranulin (PGRN) mRNA in OA cartilage tissues and normal cartilage tissues. Chondrocyte cell lines, CHON-001 and ATDC5, were treated with different doses of interleukin-1β (IL-1β) to induce the inflammatory response. Overexpression plasmids, microRNA mimics, microRNA inhibitors and small interfering RNAs were constructed and transfected into CHON-001 and ATDC5 cells. CCK-8 assay was used for determining the cell viability and Transwell assay was used for monitoring cell migration. Western blot was applied to measure the expressions of apoptosis-related proteins. Enzyme-linked immunosorbent assay (ELISA) was adopted to measure the contents of inflammatory factors. StarBase and TargetScan were used to predict the binding sites between OIP5-AS1 and miR-29b-3p, miR-29b-3p and 3′-UTR of PGRN respectively, which were verified by dual luciferase reporter assay. Results OIP5-AS1 and PGRN mRNA were downregulated while miR-29b-3p was upregulated in OA tissues and models. The up-regulated OIP5-AS1 facilitated the proliferation and migration of CHON-001 and ATDC5 cells, while ameliorated the apoptosis and inflammatory response. However, miR-29b-3p had opposite effects. PGRN was identified as a target gene of miR-29b-3p, which could be indirectly suppressed by OIP5-AS1 knockdown. Conclusion Downregulation of OIP5-AS1 induced by IL-1β could inhibit the proliferation and migration abilities of CHON-001 and ATDC5 cells and facilitate the apoptosis and inflammation response via regulating miR-29b-3p/PGRN axis.

Osteoarthritis (OA) is a common degenerative joint disease. Inflammation may exaggerate the catabolism and degeneration in the pathogenesis of OA. Hydroxytyrosol (HT) has been used in the management of inflammatory diseases. In addition, reports have revealed that autophagy was a therapeutic target of diseases caused by inflammation. Sirtuin 6 (SIRT6) has also been demonstrated to prevent OA development by reducing both the inflammatory response and chondrocyte senescence. However, the roles of SIRT6 and autophagy in cartilage and its underlying anti‑inflammatory mechanism are unknown. Therefore, the present study aimed to determine the effects of HT on autophagy and inflammation in chondrocytes, and clarify whether HT regulates the inflammatory response through SIRT6‑mediated autophagy. The expression of protein and mRNA were determined by western blot analysis and reverse transcription‑quantitative polymerase chain reaction. The production of cytokines was detected by ELISA. It was demonstrated that HT inhibited the levels of interleukin (IL)‑1β and IL‑6 in tumor necrosis factor (TNF)‑α‑stimulated chondrocytes in a concentration‑dependent manner. In addition, HT promoted cell autophagy and increased the mRNA and protein expression levels of SIRT6 in chondrocytes stimulated with TNF-α. Autophagy inhibitor 3-methyladenine or knockdown of SIRT6 decreased the inhibitory effects of HT on the inflammatory response in chondrocytes. In addition, knockdown of SIRT6 attenuated the expression of microtubule-associated protein 1A/1B‑light chain 3 and Beclin1 in chondrocytes. Overall, these findings suggested that HT inhibits the inflammatory response of chondrocytes through SIRT6‑mediated autophagy. The present study provided a new drug target for the clinical treatment of inflammatory diseases.

Despite the knowledge on many genetic variants present in osteosarcoma, the complexity of this disease precludes placing its biology into a simple conceptual framework. RECQL is a DNA helicase involved in DNA mismatch repair and has been reported to be associated with many human cancers. We aimed to investigate the association of RECQL genetic polymorphism with osteosarcoma in a Chinese population. We selected three polymorphisms of the RECQL5 gene (rs820196, rs820200, and rs4789223) in the present study. TaqMan method was utilized for genotyping these three SNPs in 212 patients with osteosarcoma and 240 age- and sex-matched noncancer controls. In our study, we found that CC genotype in rs820196 (17.5 vs 8.3%, P = 0.005) and AA genotype in rs4789223 (21.7 vs 14.2, P < 0.001) were more frequent in osteosarcoma group compared to the control group, respectively. We also found that the C allele of rs820196 (OR = 1.492, 95% CI 1.138 ∼ 1.951; P = 0.004) and A allele of rs4789223 (OR = 1.767, 95% CI: 1.354 ∼ 2.301; P < 0.001) were common in the osteosarcoma patients than those in the control subjects, respectively. Haplotype analysis showed that TTA (OR = 3.469, 95% CI 1.798 ∼ 6.695; P < 0.001) was associated with increased risk for osteosarcoma. However, the TTG (OR = 0.578, 95% CI 0.442 ∼ 0.756) was associated with decreased risk for osteosarcoma. Our results suggested that RECQL5 genetic polymorphisms were associated with osteosarcoma in a Chinese population.