Figure 7.

H. parasuis LppA induces resistin expression in vitro and in vivo. (a) PAMs were infected by wild-type SH0165, δlppa mutants, δlolb mutants, δmetq mutants, or δplpa mutants (100 MOI) for 2 h, and resistin expression in PAMs was determined using qRT-PCR. The mRNA levels of each gene were standardized to GAPDH. **p<0.01 compared with the wild-type SH0165 group. (b) PCR detection of the lppA gene deletion mutant and the complementation strain. Bacteria cells were collected to obtain total RNA, which was subsequently reverse-transcribed into cDNA. Primers P9 and P10 were used to detect lppA gene expression using PCR. WT: wild-type H. parasuis, NC: negative control, M: DL2000 marker. (c) the growth status of the wild-type SH0165, ΔlppA mutant, and C-lppA strains. Bacteria cells were cultured for 4 h, and OD600 values were measured every 3 h for each strain. (d, e) PAECs were co-cultured with wild-type PAMs, and PAMs were infected by wild-type SH0165, δlppa mutant, or C-lppA strains (100 MOI) for 2 h. The supernatant and lyses of these PAMs were then collected. The resistin expression in PAMs was analysed using qRT-PCR (d). The mRNA levels of each gene were standardized to GAPDH. The supernatant of PAMs was collected for ELISA analysis (e). (f, g) Resistin levels in serum (e) and primary porcine alveolar macrophages (g) were analysed using ELISA and qRT-PCR, respectively. (h) Adhesion to PAMs by wild-type SH0165, δlppa mutant, or C-lppA strains (100 MOI). **p<0.01. Error bars represent the mean ± SEM (n = 3).