Figure 3.

miR-21 regulates interferon-inducible protein 10 (IP-10) secretion in THP-1 cells. THP-1 cells were transfected with either miR-21 mimics or control for 48 h and subsequently stimulated by lipopolysaccharide (LPS) for another 24 h. (A) The transfection of miR-21 mimics led to enhanced expression of miR-21 in THP-1 cells. Following the transfection, IP-10 mRNA expression (B) and secretion after LPS stimulation (C) were measured. THP-1 cells were transfected with either miR-21 inhibitors or control over 48 h and stimulated by LPS for 24 h. (D) The transfection of miR-21 inhibitors triggered a decreased expression of miR-21 in THP-1 cells. The inhibition of miR-21 did not influence IP-10 mRNA levels (E) yet did increase IP-10 secretion (F). (G) Two conserved miR-21 binding sites located at the IP-10 3′UTR. Luciferase activity was significantly lower in mimic-treated cells but was slightly higher in fluorescence intensity of inhibitor-treatment cells than in the mock cells. (H) Co-transfected with miR-21 mimic and IP-10 3′UTR mut-2 (235–240), not mut-1 (196–202) vector showed more downregulated luciferase expression than the empty vector control. (I) Comparison of miR-21 expression in sorted monocytes from HIV and healthy controls (HCs). (J) Comparison of plasma IP-10 levels in HIV and HC. (K) Correlation between the miR-21 expression in CD14⁺ monocytes and plasma IP-10 level.