Gap junctions and fluid flow response in MC3T3-E1 cells

In thecurrent study, we examined the role of gap junctions in oscillatoryfluid flow-induced changes in intracellular Ca²⁺concentration and prostaglandin release in osteoblastic cells. Thiswork was completed in MC3T3-E1 cells with intact gap junctional communication as well as in MC3T3-E1 cells rendered communication deficient through expression of a dominant-negative connexin. Ourresults demonstrate that MC3T3-E1 cells with intact gap junctions respond to oscillatory fluid flow with significant increases in prostaglandin E₂ (PGE₂) release, whereas cellswith diminished gap junctional communication do not. Furthermore, wefound that cytosolic Ca²⁺ (Ca) responsewas unaltered by the disruption in gap junctional communication and wasnot significantly different among the cell lines. Thus our resultssuggest that gap junctions contribute to the PGE₂ but notto the Ca response to oscillatory fluid flow. Thesefindings implicate gap junctional intercellular communication (GJIC) inbone cell ensemble responsiveness to oscillatory fluid flow and suggestthat gap junctions and GJIC play a pivotal role in mechanotransduction mechanisms in bone.