The Urokinase Receptor (uPAR) Facilitates Clearance of Borrelia burgdorferi
Figure 1
Borrelia burgdorferi induces upregulation of the urokinase receptor on murine and human leukocytes in vitro and in vivo.
(A) Viable B. burgdorferi induces uPAR expression on murine and human macrophages. Murine peritoneal macrophages, and ex vivo generated human macrophages, (1×105) were stimulated with viable Borrelia burgdorferi (strain B31) for 16 hours (Cell∶B. burgdorferi = 1∶10 or 1∶100). Cells were harvested and analyzed for uPAR expression by FACS analysis. (B) Viable B. burgdorferi induces uPAR expression on murine and human granulocytes and monocytes. Murine and human whole blood was incubated with viable B. burgdorferi for 16 hours. Erythrocytes were lysed and cells were co-stained for granulocytes or monocytes markers and uPAR and analyzed by FACS analysis. (C) Expression of uPAR is increased in skin biopsies from Lyme borreliosis patients. Total RNA was isolated from biopsies derived from culture and PCR confirmed B. burgdorferi positive erythema migrans lesions from Lyme borreliosis patients (n = 5) or healthy controls (n = 5) and subjected to quantitative uPAR and β-actin RT-PCR. We could not detect uPAR mRNA in healthy controls, for these samples the level of uPAR mRNA was set at the detection limit. Expression of uPAR mRNA was corrected for β-actin mRNA expression and depicted as a relative number. Expression of uPAR of one of the healthy controls was set at 1. Graphs in panels (A and B) are representative of at least three independent experiments and error bars represent the mean of triplicates within one experiment±SEM. A p-value<0.05 was considered statistically significant. * indicating p<0,05; ** p<0,01 and *** p<0,001.