No effect was observed with an inactive SN50 control peptide, SN50I. SN50 also significantly lowered levels of TNF and nitrite release in response to LPS, confirming a generalized selleck inhibitor decrease in microglial activation. Second, the MEK1 2 inhibitor U0126 also fully blocked the LPS mediated effects on saquinavir accumulation by the cells and nitrite release. Conclusions Here, we investigated how LPS induced inflammation al ters the function of drug transporters in microglia, the primary CNS target of HIV, using a clinically relevant concentration of the antiretroviral medication saquinavir as a prototypical probe substrate and the fol lowing model systems, a rat microglia cell line, HAPI, and primary cultures of rat and mouse microglia.

Fur thermore, we examined at a molecular level, what mech anisms may drive the observed changes in saquinavir accumulation and retention by microglia following an inflammatory LPS challenge. As noted in another rat microglia cell line, accumulation of saquinavir into HAPI Inhibitors,Modulators,Libraries microglia cells was rapid, reached a plateau by one hour, and was increased significantly by a potent P glycoprotein inhibitor PSC833. In this model, an in crease in saquinavir accumulation in the presence of PSC833 provides an indirect measure of compound Inhibitors,Modulators,Libraries ef flux by the transporter. Following both short and long term LPS exposure in microglia, the overall accumulation of saquinavir decreased in a dose dependent manner, with significant decreases observed at 24 hours at doses greater than 2. 5 ng ml LPS.

Using LPS in the presence and absence of the P glycoprotein inhibitor PSC833, the decrease in saquinavir accumula tion Inhibitors,Modulators,Libraries was only partially explained by increases in P glyco protein function, that is, by increased P glycoprotein mediated efflux of compound from the intracellular compartment to the outside of the cell. The Inhibitors,Modulators,Libraries remainder of the unaccounted saquinavir transport surprisingly could not be explained by increases in efflux or protein expression of Mrp1, a transporter known to handle sa quinavir efficiently. Although less likely, a decrease Inhibitors,Modulators,Libraries in potential uptake of saquinavir into the cells via de creased SLC uptake transporter expression function was also considered. Transcripts of seven well characterized SLC transporters, some already well known to interact with ARs, were examined in the presence and absence of LPS.

With http://www.selleckchem.com/products/Axitinib.html the exception of Slc22a2, none of these trans porters were expressed sig nificantly in HAPI microglia. Furthermore, Slc22a2 transcript levels in HAPI microglia were unchanged fol lowing LPS exposure. Therefore, it is unlikely that a change in SLC uptake transporters explains the reduced accumulation of saquinavir following LPS treatment. While it was clear that LPS exposure decreased accumulation of saquinavir significantly in microglia, at least partially through a P glycoprotein pathway, protein levels of that transporter were unchanged.