Extracellular CIRP activates STING to exacerbate hemorrhagic shock
Kehong Chen, Joaquin Cagliani, Monowar Aziz, Chuyi Tan, Max Brenner, Ping Wang
Kehong Chen, Joaquin Cagliani, Monowar Aziz, Chuyi Tan, Max Brenner, Ping Wang
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Research Article Inflammation

Extracellular CIRP activates STING to exacerbate hemorrhagic shock

Abstract

Stimulator of IFN genes (STING) activates TANK-binding kinase 1 (TBK1) and IFN regulatory factor 3 (IRF3) to produce type I IFNs. Extracellular cold-inducible RNA-binding protein (eCIRP) is released from cells during hemorrhagic shock (HS). We hypothesized that eCIRP activates STING to induce inflammation and acute lung injury (ALI) after HS. WT and STING–/– mice underwent controlled hemorrhage by bleeding, followed by fluid resuscitation. Blood and lungs were collected at 4 hours after resuscitation. Serum ALT, AST, LDH, IL-6, and IFN-β were significantly decreased in STING–/– mice compared with WT mice after HS. In STING–/– mice, the levels of pTBK1 and pIRF3, and expression of TNF-α, IL-6, and IL-1β mRNAs and proteins in the lungs, were significantly decreased compared with WT HS mice. The 10-day mortality rate in STING–/– mice was significantly reduced. I.v. injection of recombinant mouse CIRP (rmCIRP) in STING–/– mice showed a significant decrease in pTBK1 and pIRF3 and in IFN-α and IFN-β mRNAs and proteins in the lungs compared with rmCIRP-treated WT mice. Treatment of TLR4–/–, MyD88–/–, and TRIF–/– macrophages with rmCIRP significantly decreased pTBK1 and pIRF3 levels and IFN-α and IFN-β mRNAs and proteins compared with WT macrophages. HS increases eCIRP levels, which activate STING through TLR4/MyD88/TRIF pathways to exacerbate inflammation.

Authors

Kehong Chen, Joaquin Cagliani, Monowar Aziz, Chuyi Tan, Max Brenner, Ping Wang

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Figure 2

STING–/– mice are protected against ALI in HS.

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STING–/– mice are protected against ALI in HS. WT and STING–/– mice were...
WT and STING–/– mice were subjected to sham or HS operation. After 4 hours of HS operation, lung tissues were collected from sham and HS mice. (A–F) Expression of (A and D) TNF-α, (B and E) IL-6, and (C and F) IL-1β mRNA and protein levels in lungs were assessed by real-time PCR and ELISA, respectively. (G–K) Lung tissues of WT and STING–/– HS mice were assessed for the expression of (G) CCL3, (H) CCL8, (I) CXCL1, (J) COX2, and (K) iNOS mRNA by real-time PCR. (L) MPO activity in lung tissues of WT and STING–/– sham and HS mice were assessed by enzymatic assay. Data are expressed as mean ± SEM. n = 6 mice/group. The groups were compared by 1-way ANOVA and SNK method (*P < 0.05 versus WT-sham; #P < 0.05 versus WT-HS mice). (M and N) HS was induced in WT and STING–/– mice. After 4 hours of HS, lung tissues were collected for histological analysis. (M) Representative images of H&E-stained lung tissue at 200×. Scale bar: 50 μm. (N) Lung injury scores ranged from 0 to 1 and were based on the presence of proteinaceous debris in the airspaces, the degree of septal thickening, and neutrophil infiltration in the alveolar and interstitial spaces. n = 6 high-power field images/group obtained from 6 mice/group. The experiments were performed 2 times, and all data were used for analysis. Data are expressed as mean ± SEM and compared by 1-way ANOVA and SNK method (*P < 0.05 versus WT-sham; #P < 0.05 versus WT-HS mice).