Pluto Bioinformatics

GSE157460: Interleukin-6 (IL-6) deficiency enhances intramembranous osteogenesis following stress fracture in mice

Bulk RNA sequencing

Interleukin-6 (IL-6) is highly upregulated in response to skeletal injury, suggesting it plays a role in the inflammatory phase of fracture repair. However, the impact of IL-6 on successful repair remains incompletely defined. Therefore, we investigated IL-6 in fracture repair using 12-week old IL-6 global knockout mice (IL-6 KO) and two models of fracture repair: full fracture and stress fracture. Callus formation 14 days after full fracture did not differ between IL-6 knockout mice and controls. However, IL-6 KO mice had an enhanced response 7 days after stress fracture compared to control, with increased callus (p=0.020) and bone formation (p=0.045). IL-6 KO did not alter the recruitment of neutrophils or macrophages to the stress fracture callus. IL-6 KO also did not alter the number of osteoclasts in the stress fracture callus. Based on RNA-seq, IL-6 KO resulted in only modest alterations to the gene expression at early time points after stress fracture. Wnt1 was more highly upregulated in IL-6 KO callus at both day 1 (fold change 12.5 vs. 5.7) and day 3 (fold change 4.7 vs. 1.9) compared to controls. Finally, using tibial compression to induce bone formation, we found that IL-6 KO directly impacted osteoblast function, increasing the propensity for woven bone formation. Herein, we report that IL-6 knockout enhanced formation of callus and bone following stress fracture injury, likely through direct action on the osteoblasts ability to produce woven bone. This suggests a novel role of IL-6 as a suppressor of intramembranous bone formation. SOURCE: Jennifer,Ann,McKenzieMatthew Silva Washington University in St. Louis