Association of Gremlin-2 gene polymorphisms with osteoporosis risk in Chinese postmenopausal women

Recent Advance in Regulatory Effect of GRP120 on Bone Metabolism

The link between fatty acids and bone metabolism is complex and can be direct and indirect. This link has been reported in different types of bone cells and various stages of bone metabolism. G-protein coupled receptor 120 (GPR120), also called free fatty acid receptor 4 (FFAR4), is a member of the recently discovered G protein-coupled receptor family that can interact with both long-chain saturated fatty acids (C14-C18) and long-chain unsaturated fatty acids (C16-C22). Research shows that GPR120 regulates processes in different types of bone cells, directly or indirectly affecting bone metabolism. Our research reviewed the literature on the effects of GPR120 on bone marrow mesenchymal stem cells (BMMSCs), osteoblasts, osteoclasts, and chondrocytes, focusing on the research findings regarding the mechanism by which GPR120 alters specific bone metabolic diseases-osteoporosis and osteoarthritis. The data reviewed here provide a basis for clinical and basic research into the role of GPR120 on bone metabolic diseases.

Effect of Rhizoma Drynariae on differential gene expression in ovariectomized rats with osteoporosis based on transcriptome sequencing

Osteoporosis is increasingly becoming a serious problem affecting the quality of life of the older population. Several experimental studies have shown that Chinese medicine has a definite effect on improving osteoporosis. Based on transcriptome sequencing, we analyzed the differential gene expression and mechanism of the related signaling pathways. Fifteen rats were randomly divided into an experimental group, a model group, and a sham surgery group. The rat model for menopausal osteoporosis was established using an ovariectomy method. One week after modeling, the experimental group was administered(intragastric administration)8.1 g/kg of Rhizoma drynariae, whereas the model and sham groups received 0.9% saline solution twice daily for 12 weeks. Subsequently, the rats were sacrificed, and the left femur of each group was removed for computerized tomography testing, while right femurs were used for hematoxylin and eosin staining. High-throughput RNA sequencing and functional and pathway enrichment analyses were performed. Comparing the gene expression between the experimental and model groups, 149 differential genes were identified, of which 44 were downregulated and 105 were upregulated. The criteria for statistical significance were |log2 Fold Change| > 1 and P < 0.05. Gene ontology analysis showed that the differentially expressed genes were enriched in cell component terms such as cell part and outer cell membrane part, and the genes were associated with cell process, biological regulation, metabolic processes, DNA transcription, and catalytic activity. Enrichment analysis of Kyoto Encyclopedia of Genes and Genomes pathways showed significantly enriched pathways associated with systemic lupus erythematosus, herpes simplex infection, circadian rhythm, vascular smooth muscle contraction, the AGE-RAGE signaling pathway in diabetic complications, and the TNF, Apelin, and Ras signaling pathways. Our results revealed that the Npas2, Dbp, Rt1, Arntl, Grem2, H2bc9, LOC501233, Pla2g2c, Hpgd, Pde6c, and Dner genes, and the circadian rhythm, lipid metabolism, inflammatory signaling pathway, and immune pathways may be the key targets and pathways for traditional Chinese medicine therapy of Rhizoma Drynariae in osteoporosis.

Genetic variation in NOD1/CARD4 and NOD2/CARD15 immune sensors and risk of osteoporosis

The present study was aimed to investigate the relationship between NOD1/CARD4 and NOD2/CARD15 gene polymorphisms and osteoporosis in the Turkish population. The first time we thought that the functional polymorphisms in NOD1/CARD4 and NOD2/CARD15 genes might have triggered the development of osteoporosis. The objective of our study was to determine the relationship between NOD1/CARD4 and NOD2/CARD15 SNPs and osteoporosis. The NOD1/CARD4 (rs5743336) and NOD2/CARD15 (rs2066847) SNPs were analyzed by PCR restriction fragment length polymorphism (PCR-RFLP) in 94 healthy controls and 164 subjects with osteoporosis. PCR products were digested with restriction enzymes AvaI for NOD1/CARD4 and ApaI for NOD2/CARD15. We found that NOD1/CARD4 genotype distribution of AA, GA and GG were 15, 44 and 41% for patients and 17, 46 and 37% for controls, respectively. NOD2/CARD15 mutation was found only in three patients (1.8%) as heterozygote. The results did not show any statistical difference between NOD1/CARD4 and NOD2/CARD15 genotype distribution of patients and healthy groups (χ² = 1.740, P=0.187; χ² = 1.311, P=0.519). However, the most frequent AG genotype (46%) of NOD1/CARD4 was observed in healthy controls, GG genotype (44%) of NOD1/CARD4 was observed as the most frequent in osteoporotic patients. NOD2/CARD15 WT/WT genotype, the most frequent genotype, was observed in both groups. Statistical analysis revealed that NOD1/CARD4 and NOD2/CARD15 polymorphisms are not associated with osteoporosis. However, a definite judgement is difficult to be made due to restricted number of patients and small size of control group. Further research is sorely warranted in this direction.