Chronic inflammation differentially regulates the expression of LPARs and ENPP2 in mouse brain and FACS-sorted microglia. a Schematic diagram outlining the treatment and experimental regimen. Mice (n = 5 per group) received i.p. injections of either PBS or LPS (1.4 mg/kg body weight) once every 24 h over a 96-h period. Dissection of the brain for further analyses was performed after 48 and 96 h. b One dissected hemisphere from each mouse was processed for RNA isolation and qPCR analysis. Expression ratios were normalized to HPRT and results were analyzed using the relative expression software tool (REST; **p < 0.01, ***p < 0.001; pairwise re-allocation test). The dotted lines indicate 2-fold up- or downregulation. c The levels of LPA in the brain (at 48 and 96 h) were quantified using an ELISA. Results are expressed as mean ± SD (***p < 0.001; unpaired Student’s t test). d In a second cohort of animals (n = 5), microglia were isolated from freshly dissected brains by FACS 96 h post LPS treatment. Sorted microglia were processed for RNA isolation and further analysis by qPCR. Expression ratios of LPAR1-6, ENPP2, and PLA2G4 (coding for cPLA2) were normalized to HPRT. Results were analyzed using the relative expression software tool (REST; *p < 0.05; pairwise re-allocation test).