Liver X Receptor Expression and Pentraxin 3 Production in Chronic Rhinosinusitis and Sinonasal Mucosal Fibroblast Cells

The Impact of Pentraxin 3 on Crohn's Disease Phenotype

Pentraxin 3 [PTX3] is an acute-phase protein playing an important role in the regulation of the humoral arm of immune response. As one of the molecules from the conservative family of pentraxins, PTX3 is a soluble mediator involved in the transduction of pro-inflammatory signals between immunocompetent cells. Additionally, recognizing damage-associated molecular patterns (DAMPs) during tissue injury mediates wound healing; therefore, its concentration potentially correlates with the severity of fibrosis. The aim of our study was to evaluate the value of the PTX3 measurement as a phenotypic marker of the stenotic form of Crohn's disease. The research covered 63 patients, 35 with the narrowing type (B2) and 28 with the inflammatory type (B2) of CD. The mean concentrations of PTX3 in the study were as follows: 3.06 ng/mL (95% CI: 1.27-6.99) for the B1 phenotype, 4.89 ng/mL (95% CI: 2.98-13.65) for the B2 phenotype, and 3.04 ng/mL (95% CI: 1.01-4.97) for the control group. PTX3 concentrations reached the highest values in the B2 group and the lowest in the control group. The differences between the B1 and B2 groups were statistically significant at p < 0.001. The presented studies indicate the potential role of PTX3 in the monitoring of tissue remodeling and the development of fibrosis in CD.

Novel involvement of PLD-PKCδ-CREB axis in regulating FGF-2-mediated pentraxin 3 production in human nasal fibroblast cells

A higher expression level of mitogenic fibroblast growth factor-2 (FGF-2) has been reported in human nasal mucus of both chronic rhinosinusitis (CRS) with nasal polyps (CRSwNP) and CRS without nasal polyps (CRSsNP). Meanwhile, we have shown that long pentraxin 3 (PTX3), an essential component of humoral innate immunity that is produced at sites of infection and inflammation, was overproduced in human nasal mucosae and secretions of CRSsNP. Therefore, this study was aimed to investigate how FGF-2 regulates PTX3 expression in human CRSsNP nasal mucosa-derived fibroblast cells (hNMDFs). The FGF-2 treatment caused ptx3 mRNA expression and PTX3 protein induction and secretion. In parallel, a differential expression of FGF receptor (FGFR)-1 to FGFR-4 was observed in hNMDFs and human nasal tissues. While conventionally known PI3K/Akt/mTOR and AP-1 pathways following FGFR activation were shown to be involved, the protein kinase Cδ (PKCδ) and cAMP response element-binding protein (CREB) were also found to be as critical signaling molecules in FGF-2-induced PTX3 induction. The PKCδ and CREB activation could be detected in total cells and in the cell nucleus. Accordingly, a novel CREB binding sequence was detected in the human ptx3 promoter region and could interact with activated CREB in cells challenged with FGF-2. Surprisingly, the phospholipase D (PLD), but not phosphoinositide- and phosphatidylcholine-phospholipase C, was necessarily required for PKCδ and CREB activation. Therefore, we demonstrated here for the first time that FGF-2 mediates PTX3 production not only through PI-3K/Akt/mTOR and AP-1 activation, but also through a novel FGFR-PLD-PKCδ-CREB cellular signaling pathway.