Increased Expression of the NOD-like Receptor Family, Pyrin Domain Containing 3 Inflammasome in Dermatomyositis and Polymyositis is a Potential Contributor to Their Pathogenesis.
BACKGROUND
Dermatomyositis (DM) and polymyositis (PM) are common inflammatory myopathies whose immunopathogenic mechanisms remain poorly understood. The NOD-like receptor family, pyrin domain containing 3 (NLRP3) inflammasome is a type of cytoplasmic multiprotein inflammasome and is responsible for the activation of inflammatory reactivations. Responding to a wide range of exogenous and endogenous microbial or sterile stimuli, NLRP3 inflammasomes can cleave pro-caspase-1 into active caspase-1, which processes the pro-inflammatory cytokines pro-interleukin (IL)-1β and pro-IL-18 into active and secreted IL-1β and IL-18. The NLRP3 inflammasome is implicated in infectious and sterile inflammatory diseases. However, it remains unclear whether it is involved in the pathogenesis of DM/PM, which we aim to address in our research.


METHODS
In this study, 22 DM/PM patients and 24 controls were recruited. The protein and RNA expression of IL-1β, IL-18, NLRP3, and caspase-1 in serum and muscle samples were tested and compared between the two groups.


RESULTS
The serum IL-1β and IL-18 levels were significantly higher in DM/PM patients than those in the controls by enzyme linked immunosorbent assay (ELISA, DM vs. control, 25.02 ± 8.29 ng/ml vs. 16.49 ± 3.30 ng/ml,P < 0.001; PM vs. control, 26.49 ± 7.79 ng/ml vs. 16.49 ± 3.30 ng/ml,P < 0.001). Moreover, the real-time quantitative reverse transcription-polymerase chain reaction (qRT-PCR) showed that DM/PM patients exhibited higher RNA expression of IL-1β, IL-18, and NLRP3 in the muscle (for IL-1β, DM vs. control, P= 0.0012, PM vs. control, P= 0.0021; for IL-18, DM vs. control, P= 0.0045, PM vs. control, P= 0.0031; for NLRP3, DM vs. control, P= 0.0017, PM vs. control, P= 0.0006). Moreover, the protein expression of NLRP3 and caspase-1 in muscle samples of DM/PM patients were also significantly elevated compared to that in the muscles of the controls.


CONCLUSIONS
Our findings demonstrate that the NLRP3 inflammasome is implicated in the pathogenesis of DM/PM. High NLRP3 expression led to elevated levels of IL-1β and IL-18 and could be one of the factors promoting disease progress.
Xi
X
Yin
Gen-Cheng
GC
Han
Xing-Wei
XW
Jiang
Qiang
Q
Shi
Department of Neurology, Chinese People's Liberation Army General Hospital, Beijing 100853, China.
Chuan-Qiang
CQ
Pu
D000328:Adult; D020170:Caspase 1 / Q000032:analysis / Q000235:genetics; D003882:Dermatomyositis / Q000209:etiology*; D005260:Female; D006801:Humans; D058847:Inflammasomes / Q000502:physiology*; D020382:Interleukin-18 / Q000032:analysis / Q000235:genetics; D053583:Interleukin-1beta / Q000032:analysis / Q000235:genetics; D008297:Male; D008875:Middle Aged; D000071199:NLR Family, Pyrin Domain-Containing 3 Protein / Q000032:analysis / Q000235:genetics / Q000502:physiology*; D017285:Polymyositis / Q000209:etiology*
D058847:Inflammasomes; D020382:Interleukin-18; D053583:Interleukin-1beta; D000071199:NLR Family, Pyrin Domain-Containing 3 Protein; C453881:NLRP3 protein, human; D020170:Caspase 1