Adhesion of monocytic and astroglial cells: Effects of inflammatory mediators

Monocytic and astroglial cells interact in culture to cause the release of several neuroactive compounds. The mechanism by which this occurs is unknown, though adhesion between these two cell types has been suggested as a possible triggering event. In the present study we sought to demonstrate monocytic binding to astroglial cells, and to elucidate molecular factors that may influence this association. Stimulation of U373-MG human astroglioma cells with several pro-inflammatory substances, including the tumor promoter phorbolmyristate acetate (PMA) and the bacterial cell wall component lipopolysaccharide (LPS), as well as cytokines IL-1α, TNF-α and INF-γ, was found to significantly enhance the attachment of U937 human monocytic cells. It was further observed that stimulation of U937 cells with PMA greatly augmented their adherence to untreated U373-MG cells, but not to each other. These findings are discussed in relation to mechanisms of neural damage in CNS inflammatory/infectious disease.