Iron accumulation is a risk factor of osteoporosis; mechanisms leading to iron-related bone loss are not fully determined. We sought to better understand the effect of chronic iron accumulation on bone over the life span in a mouse model. Hepcidin1 knockout (Hepc1(-/-)) male mice and their littermate control wild type (WT) mice at 7 months old were used in this study. Serum iron and ferritin as well as iron contents in liver and femur were significantly increased in Hepc1(-/-) mice compared to WT mice. We found that Hepc1(-/-) mice had a phenotype of low bone mass and alteration of the bone microarchitecture, most likely caused by a decreased osteoblastic activity. Cell culture studies indicated that chronic iron accumulation decreased bone formation, probably by affecting bone morphogenetic protein signaling.

Background Osteoporosis (OP) is a bone disease characterized by reduced amount and quality of bone. This study was designed to explore the role and mechanism of lncRNA IGF2‐AS in the osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs). Methods Human lncRNA and miRNA microarray analyses were performed to measure the differential expression levels of lncRNAs and miRNAs in undifferentiated and osteogenically differentiated BMSCs. lncRNA IGF2‐AS, miR‐3,126‐5p, and KLK4 levels were measured by real‐time quantitative polymerase chain reaction (RT‐qPCR). Osteogenic differentiation of BMSCs was assessed by alkaline phosphatase (ALP) staining and Alizarin Red staining (ARS). Protein levels of osterix (Osx), osteocalcin (OCN), and runt‐related transcription factor 2 (RUNX2) were examined by RT‐PCR and western blot assays. The binding relationship between miR‐3,126‐5p and lncRNA IGF2‐AS or KLK4 was predicted by TargetScan (http://www.targetscan.org/vert_72/) and then verified with a dual‐luciferase reporter assay. Results lncRNA IGF2‐AS and KLK4 were highly expressed and miR‐3,126‐5p was weakly expressed in osteogenically differentiated BMSCs. Moreover, lncRNA IGF2‐AS overexpression enhanced the osteogenic differentiation of BMSCs. In contrast, lncRNA IGF2‐AS knockdown showed the opposite trend. Moreover, miR‐3,126‐5p overexpression abolished the lncRNA IGF2‐AS‐mediated osteogenic differentiation of BMSCs. lncRNA IGF2‐AS functions as a sponge of miR‐3,126‐5p to regulate KLK4 expression. Conclusion lncRNA IGF2‐AS enhances the osteogenic differentiation of BMSCs by modulating the miR‐3,126‐5p/KLK4 axis, suggesting a promising therapeutic target for bone‐related diseases.