Pentraxin 3 promotes the expression of pro-inflammatory cytokines and the migration of macrophages in myocarditis.

BACKGROUND

This study aims to investigate the expression of Pentraxin 3 (PTX3) and Nod-like receptor family pyrin domain-containing 3 (NLRP3) in myocarditis and to elucidate their roles and potential interplay in the pathogenesis of myocarditis.

METHODS

Immunofluorescence staining was performed on myocardial autopsy specimens from deceased patients with severe myocarditis or severe trauma. H9C2 cardiomyocytes were divided into five groups: Control, Lipopolysaccharide (LPS), LPS + PTX3 overexpression, LPS + small interfering RNA targeting PTX3 (si-PTX3), and LPS + PTX3 overexpression + si-NLRP3. The expression levels of PTX3 and NLRP3 at the RNA level were quantified using quantitative real-time polymerase chain reaction (qPCR), while protein expression was assessed via western blot. The concentrations of interleukin-1β (IL-1β) and IL-18 were determined by enzyme-linked immunosorbent assay (ELISA). Macrophages migration was evaluated using Transwell assays.

RESULTS

Immunofluorescence staining revealed co-localization and increased expression of PTX3 and NLRP3 in the myocardium of patients with severe myocarditis. In vitro experiments demonstrated that PTX3 enhanced the expression of NLRP3, IL-1β, and IL-18 in LPS-stimulated cardiomyocytes. Furthermore, PTX3 was shown to promote macrophage migration by regulating NLRP3 expression, as assessed by Transwell assays.

CONCLUSION

Our findings suggest that PTX3-mediated NLRP3 activation contributes to inflammatory responses and promotes macrophage migration in myocarditis. This study provides a foundation for future investigations into PTX3-targeted therapies for myocarditis.