Figure 5. Effect of DEX on CD47 and SIRPA expression. A: Schematic diagram showing that CD47 can interact with αvβ3 integrin on the same cell or with SIRPα on an adjacent cell. CD47 can also bind thrombospondin-1 (TSP), which promotes an interaction between CD47 and αvβ3 integrin and triggers αvβ3 integrin signaling [36,37]. B: qPCR analyses showed that DEX treatment caused the downregulation of SIRPA mRNA by day 5 of treatment compared to the no trt group at day 0. In contrast, EtOH-treated controls showed an increase in mRNA levels starting on day 2 of the treatment. All these changes were statistically significant (*) at p<0.05 compared to the no trt cells. The mRNA levels were normalized to the no trt group. All five HTM cell strains (N27TM-2, N27TM-4, N27TM-5, N27TM-6, and N25TM-8) were used for the qPCR analyses; n=5. C: Western blot analyses showed that protein levels of SIRPα were decreased by DEX compared to EtOH-treated controls. The figure is a representative blot done on cell lysates from three separate experiments using the N25TM-8 cell strain. β-actin was used as a loading control. Equal amounts of protein from the DEX- and EtOH-treated cell lysates were loaded; n=3. D: FACS analyses of CD47 and αvβ3 integrin levels in HTM cells (N27TM-4) in the presence of DEX or a vehicle. Analyses were done in duplicate and verified in two independent experiments using both N27TM-2 and N27TM-4 cells. DEX caused an increase in αvβ3 integrin levels but not CD47; n=2.