Fig. 5. PSAP mediates atherosclerotic plaque inflammation in humans.

(A-D) Human primary monocytes were incubated with oxidized LDL (oxLDL) or prosaposin for 24 hours. Media only (RPMI) was used as control. After a 5-day rest, cells were restimulated with LPS. (A) TNFα production upon LPS stimulation, as measured by ELISA (n = 6). (B) TNFα production of human monocytes primed with oxLDL in combination with mTORi-NB or S6K1i-NB as compared to unloaded NB or oxLDL only (n = 6). (C) Single cell transcriptome analysis of adherent human monocytes after oxLDL priming and LPS restimulation. Uniform Manifold Approximation and Projection (UMAP) plot shows the different monocyte clusters and PSAP expression is shown for each cell (n = 3). (D) Human monocytes were primed with prosaposin or RPMI (negative control) for 24 hours. After a 5-day rest, cells were restimulated with LPS and TNFα production was measured by ELISA, (n = 5). (E) Representative images of CD68 (top) and prosaposin (middle and bottom) staining on a human carotid endarterectomy sample (n = 4, see also fig. S7). (F) Single-cell RNA sequencing of human atherosclerotic plaques identifies 14 leukocyte subsets. (n = 18). (G,H) Transcriptomic analyses were performed on human atherosclerotic plaques (n = 620). Heatmap depicting co-expression of PSAP and genes involved in (G) the mTOR signaling pathway or (H) atherosclerotic plaque macrophages, clustered based on co-expression values. (I) Expression of 6 inflammatory genes, as compared to PSAP expression, based on single-cell RNA sequencing, also presented in (F). Experiments were performed once. Bar graphs are presented as mean ± SD, Wilcoxon signed-rank test were used in A, B and D. *P < 0.05.