Linoleic acid blunts early osteoblast differentiation and impairs oxidative phosphorylation in vitro

Background

Linoleic acid (LNA), an essential polyunsaturated fatty acid (PUFA), plays a crucial role in cellular functions. However, excessive intake of LNA, characteristic of Western diets, can have detrimental effects on cells and organs. Human observational studies have shown an inverse relationship between plasma LNA concentrations and bone mineral density. The mechanism by which LNA impairs the skeleton is unclear, and there is a paucity of research on the effects of LNA on bone-forming osteoblasts.

Methods

The effect of LNA on osteoblast differentiation, cellular bioenergetics, and production of oxidized PUFA metabolites in vitro, was studied using primary mouse bone marrow stromal cells (BMSC) and MC3T3-E1 osteoblast precursors.

Results

LNA treatment decreased alkaline phosphatase activity, an early marker of osteoblast differentiation, but had no effect on committed osteoblasts or on mineralization by differentiated osteoblasts. LNA suppressed osteoblast commitment by blunting the expression of Runx2 and Osterix, key transcription factors involved in osteoblast differentiation, and other key osteoblast-related factors involved in bone formation. LNA treatment was associated with increased production of oxidized LNA- and arachidonic acid-derived metabolites and blunted oxidative phosphorylation, resulting in decreased ATP production.

Conclusion

Our results show that LNA inhibited early differentiation of osteoblasts and this inhibitory effect was associated with increased production of oxidized PUFA metabolites that likely impaired energy production via oxidative phosphorylation.