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Deficiency of Phospholipase A2 Receptor Exacerbates Autoimmune Myocarditis in Mice
Secretory phospholipase A 2 (sPLA 2 ) plays a critical role in the pathogenesis of various inflammatory diseases through production of pro-inflammatory eicosanoids. PLA 2 receptor 1 (PLA 2 R) acts as a clearance receptor for sPLA 2 s. This study examined whether PLA 2 R plays a role in the pathogene...
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Published in: | Inflammation 2020-06, Vol.43 (3), p.1097-1109 |
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Main Authors: | , , , , , |
Format: | Article |
Language: | English |
Subjects: | |
Citations: | Items that this one cites Items that cite this one |
Online Access: | Get full text |
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Summary: | Secretory phospholipase A
2
(sPLA
2
) plays a critical role in the pathogenesis of various inflammatory diseases through production of pro-inflammatory eicosanoids. PLA
2
receptor 1 (PLA
2
R) acts as a clearance receptor for sPLA
2
s. This study examined whether PLA
2
R plays a role in the pathogenesis of experimental autoimmune myocarditis using PLA
2
R-deficient (PLA
2
R KO) mice on a BALB/c background. Autoimmune myocarditis was induced by immunization with murine α-myosin heavy chain. In the immunostaining of PLA
2
R wild-type (WT) myocardium, PLA
2
R and sPLA
2
s were expressed in α-SMA
+
cells and neutrophils, respectively. In immunoblot analyses, tissue from PLA
2
R KO myocardium after immunization had five to tenfold increases in the protein level of sPLA
2
-IB and sPLA
2
-IIA compared with PLA
2
R WT myocardium. However, the mRNA expression levels of these sPLA
2
s were similar in PLA
2
R KO and WT myocardium. Compared with PLA
2
R WT myocardium, PLA
2
R KO myocardium after immunization showed 40% increase in areas affected by infiltration of inflammatory cells, eight to tenfold increase in levels of PGE
2
and TXB
2
, and a threefold increase in number of Th17 cells in heart infiltrates assessed by flow cytometric analysis. Finally, PGE
2
promoted IL-23-induced expansion of Th17 cells
in vitro
. In conclusion, PLA
2
R-deficiency increased sPLA
2
-IB and sPLA
2
-IIA levels in the myocardium after immunization probably through impaired clearance, leading to increased levels of PGE
2
in the myocardium. Elevated PGE
2
induced Th17 cell expansion, exacerbating myocarditis in PLA
2
R KO mice. Thus, PLA
2
R plays an important role in pathogenesis of experimental autoimmune myocarditis. |
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ISSN: | 0360-3997 1573-2576 |
DOI: | 10.1007/s10753-020-01195-z |