Figure 4.

C. pneumoniae infection–induced FABP4 secretion is regulated by cytoplasmic calcium elevation. A, intracellular Ca²⁺ was assessed by Fluo-4 AM fluorescence in 3T3-L1 adipocytes after mock or Cpn infection for 2, 4, 12, and 24 h. Thapsigargin (10 μm) for 6 h served as a positive control. B and C, FABP4 (B) and glycerol (C) levels in cultured medium of 3T3-L1 adipocytes at 24 h after Cpn infection at a MOI of 5 in the presence or absence of BAPTA-AM (20 μm). D, the number of infectious EB progeny of 3T3-L1 adipocytes at 24 h after Cpn infection in the presence or absence of BAPTA-AM (20 μm) or BAPTA (50 μm) was determined using an IFU assay (n = 3/group; B–D). *, p < 0.05; **, p < 0.01, one-way ANOVA (B–D). The data are shown as the means ± S.E. and are representative of at least three experiments.