The effect of Chlamydia pneumoniae on the expression of peroxisome proliferator-activated receptor-gamma in vascular smooth muscle cells

Chlamydia pneumoniae heat shock protein 60 is associated with apoptotic signaling pathway in human atheromatous plaques of coronary artery disease patients

BACKGROUND

Chlamydia pneumoniae heat shock protein (HSP) 60 is known to contribute to the activation of inflammation. In addition, there are contradictory reports on C. pneumoniae and their role in activation of pathways (apoptotic/antiapoptotic/necrosis) in coronary artery disease (CAD). Hence, more studies are required to know the actual role of C. pneumoniae in activation of apoptotic/antiapoptotic/necrosis pathways.

METHODS AND RESULTS

In this study, two sets of patient groups (cHSP60 positive and cHSP60 negative) were included and gene expression was studied by cDNA micro array and real time polymerase chain reaction arrays. Expression of Caspase-3, 8, 9, c-FLIP, PPAR-γ, PGC-1α, and Gsk-3b were also evaluated at protein level by immunoblotting. In cHSP60 positive CAD patients significantly higher (p<0.001) mRNA expression was found for CCL4, CXCL4, CXCL9, IL-8, CD40LG, CD8, TGFβ1, TGFβ2, APOE, EGR1, CTGF, APOB, LDLR, LPA, and LPL, whereas significantly lower (p<0.001) mRNA expression was detected for CD4, IL1F10, IFNA2, and IL-10 as compared to cHSP60 negative CAD patients. Additionally, at protein level expression of Caspase-3 (p=0.027), 8 (p=0.028), and 9 (p=0.037) were higher and c-FLIP (p=0.028) and PPAR-γ (p=0.95) expression were comparable in cHSP60 positive CAD patients compared to cHSP60 negative CAD patients.

CONCLUSION

Genes/proteins of pre-apoptotic caspase dependent/independent pathways, chemokines, and inflammatory cytokines receptors were significantly up-regulated in human atheromatous plaques of cHSP60 positive CAD patients suggesting an association of cHSP60 with CAD.

Preterm and infection-driven preterm labor: the role of peroxisome proliferator-activated receptors and retinoid X receptor

Approximately 8% of births are complicated by preterm delivery. To improve neonatal outcomes, a greater understanding of the mechanisms surrounding preterm parturition is required. Peroxisome proliferator-activated receptors (PPARs) have been implicated in the regulation of labor at term where they exhibit anti-inflammatory properties. Thus, we hypothesize that dysregulation of PPAR expression and activity may be associated with preterm labor and infection-associated preterm labor. The aim of this study was to compare the expression and activity of PPARs and the expression of retinoid X-receptor α (RXRA) in gestational tissues from term and preterm deliveries, and from infection-associated preterm deliveries. Quantitative RT-PCR, western blotting and activity ELISA were used to study expression and DNA binding profiles. Compared with term, preterm parturition was associated with an increased expression of PPAR δ (PPARD; mRNA and protein), PPAR γ (PPARG; protein) and RXRA (protein) in the placenta and PPARD (mRNA and protein) and RXRA (mRNA) in the choriodecidua. There was, however, no change in preterm PPAR DNA binding activity compared with term. Preterm chorioamnionitis (CAM) demonstrated protein degradation in the choriodecidua and was associated with a decline in the mRNA expression of PPAR α (PPARA) and RXRA compared with uninfected preterm cases. PPAR DNA binding activity increased in the placenta (PPARD and PPARG) and decreased in the amnion (PPARA and PPARG) in association with preterm CAM. In conclusion, idiopathic preterm deliveries were associated with an increase in PPAR:RXR expression and preterm CAM was associated with a decrease in PPAR:RXR expression and tissue-specific alterations in transcriptional activity. The reasons for such dysregulation remain to be determined; however, the data are consistent with the hypothesis that PPARs may play a role in preterm labor and infection-complicated preterm deliveries.