Level of Decoy Receptor 3 for Monitoring Clinical Progression of Severe Burn Patients

Decoy receptor 3 as a prognostic biomarker for sepsis and septic shock according to the Sepsis-3 definitions

Objectives

The present study was conducted to reappraise the prognostic value of decoy receptor 3 (DcR3) for patients with sepsis and septic shock according to the latest Sepsis-3 definitions.

Methods

Subjects suffering from sepsis or septic shock were enrolled within 6 h of admission. The Sequential Organ Failure Assessment (SOFA) score and the plasma levels of DcR3, C-reactive protein, procalcitonin, and interleukin-6 were measured. Group comparisons were made based on the survival status on day 28 after onset. Predictors of mortality were assessed using the Cox proportional hazard models, and survival curves were plotted with the Kaplan-Meier method. Discriminative performances of single and combined indicators were evaluated via the areas under receiver operating characteristic curves.

Results

Among 143 eligible sepsis cases, 77 developed septic shock, and the 28-day mortality rates were 32.2% and 45.5%, respectively. Regardless of the population (all sepsis or septic shock), non-survivors exhibited significantly higher DcR3 levels compared to survivors (median 4.19 vs. 2.64 ng/mL and 4.37 vs. 3.18 ng/mL, respectively; p < 0.001 and p = 0.002, respectively). DcR3 levels were most correlated with organ dysfunction presented by SOFA scores (correlation coefficient = 0.347 and 0.308, respectively; p = 0.001 and 0.016, respectively) but did not differ among the various pathogenic microbes of infection. Multivariate Cox regression identified DcR3 as an independent predictor of mortality [hazard ratio (95% confidence interval): 1.570 (1.048-2.352) and 1.828 (1.047-3.194), respectively; p = 0.029 and 0.034, respectively]. Kaplan-Meier analysis showed that elevated DcR3 concentrations were associated with significantly lower survival rates (p = 0.001 and 0.013, respectively). The areas under receiver operating characteristic curves of DcR3 alone for predicting outcome were superior to that of the other three biomarkers (0.731 and 0.711, respectively) and could be further improved when coupled with SOFA scores (0.803 and 0.784, respectively).

Conclusions

DcR3 is a valuable prognostic biomarker for sepsis and septic shock, offering the potential to predict 28-day mortality in clinical settings.

Protective effects of DcR3-SUMO on lipopolysaccharide-induced inflammatory cells and septic mice

Despite the high mortality rate associated with sepsis, no specific drugs are available. Decoy receptor 3 (DcR3) is now considered a valuable biomarker and therapeutic target for managing inflammatory conditions. DcR3-SUMO, an analog of DcR3, has a simple production process and high yield. However, its precise underlying mechanisms in sepsis remain unclear. This study investigated the protective effects of DcR3-SUMO on lipopolysaccharide (LPS)-induced inflammatory cells and septic mice. We evaluated the effects of DcR3 intervention and overexpression on intracellular inflammatory cytokine levels in vitro. DcR3-SUMO significantly reduced cytokine levels within inflammatory cells, and notably increased DcR3 protein and mRNA levels in LPS-induced septic mice, confirming its anti-inflammatory efficacy. Our in vitro and in vivo results demonstrated comparable anti-inflammatory effects between DcR3-SUMO and native DcR3. DcR3-SUMO protein administration in septic mice notably enhanced tissue morphology, decreased sepsis scores, and elevated survival rates. Furthermore, DcR3-SUMO treatment effectively lowered inflammatory cytokine levels in the serum, liver, and lung tissues, and mitigated the extent of tissue damage. AlphaFold3 structural predictions indicated that DcR3-SUMO, similar to DcR3, effectively interacts with the three pro-apoptotic ligands, namely TL1A, LIGHT, and FasL. Collectively, DcR3-SUMO and DcR3 exhibit comparable anti-inflammatory effects, making DcR3-SUMO a promising therapeutic agent for sepsis.

Inhibitory mechanisms of decoy receptor 3 in cecal ligation and puncture-induced sepsis

Despite its high mortality, specific and effective drugs for sepsis are lacking. Decoy receptor 3 (DcR3) is a potential biomarker for the progression of inflammatory diseases. The recombinant human DcR3-Fc chimera protein (DcR3.Fc) suppresses inflammatory responses in mice with sepsis, which is critical for improving survival. The Fc region can exert detrimental effects on the patient, and endogenous peptides are highly conducive to clinical application. However, the mechanisms underlying the effects of DcR3 on sepsis are unknown. Herein, we aimed to demonstrate that DcR3 may be beneficial in treating sepsis and investigated its mechanism of action. Recombinant DcR3 was obtained in vitro. Postoperative DcR3 treatment was performed in mouse models of lipopolysaccharide- and cecal ligation and puncture (CLP)-induced sepsis, and their underlying molecular mechanisms were explored. DcR3 inhibited sustained excessive inflammation in vitro, increased the survival rate, reduced the proinflammatory cytokine levels, changed the circulating immune cell composition, regulated the gut microbiota, and induced short-chain fatty acid synthesis in vivo. Thus, DcR3 protects against CLP-induced sepsis by inhibiting the inflammatory response and apoptosis. Our study provides valuable insights into the molecular mechanisms associated with the protective effects of DcR3 against sepsis, paving the way for future clinical studies.

IMPORTANCE

Sepsis affects millions of hospitalized patients worldwide each year, but there are no sepsis-specific drugs, which makes sepsis therapies urgently needed. Suppression of excessive inflammatory responses is important for improving the survival of patients with sepsis. Our results demonstrate that DcR3 ameliorates sepsis in mice by attenuating systematic inflammation and modulating gut microbiota, and unveil the molecular mechanism underlying its anti-inflammatory effect.

HIF-1α regulates DcR3 to promote the development of endometriosis

OBJECTIVE

The aim of this study was to investigate the expression and clinical significance of HIF-1α and DcR3 in endometriosis by analysing clinical case data. Tissue samples were collected for tissue chip analysis and staining, and human endometrial stromal cells were isolated and cultured for cell experiments. Additionally, experiments were conducted on collected peritoneal fluid to explore the association and role of HIF-1α and DcR3 in endometriosis.

STUDY DESIGN

Patients who visited the Department of Obstetrics and Gynaecology at Central Hospital in Fengxian District, Shanghai, from January 2018 to December 2021 were recruited for this controlled study. Clinical data and tissue chip staining results were collected for multiple regression analysis on the clinical significance of HIF-1α and DcR3. Endometrial tissue, ovarian cysts, and pelvic fluid were collected, and human endometrial stromal cells were cultured. The impact of HIF-1α on DcR3 in different oxygen environments and its role in endometriosis were investigated through PCR, Western blotting, enzyme-linked immunosorbent assay, as well as adhesion and migration assays.

RESULTS

In patients with endometriosis, the expression of DcR3 and HIF-1α was found to be upregulated and correlated in ectopic endometrium. The expression of DcR3 served as an indicator of the severity of endometriosis. Hypoxia induced the expression of DcR3, which was regulated by HIF-1α and promoted migration and adhesion.

CONCLUSION

DcR3 can be used as a clinical indicator to assess the severity of endometriosis. The hypoxic environment in endometriosis enhances disease progression by regulating DcR3 through HIF-1α.

Research Progress of DcR3 in the Diagnosis and Treatment of Sepsis

Decoy receptor 3 (DcR3), a soluble glycosylated protein in the tumor necrosis factor receptor superfamily, plays a role in tumor and inflammatory diseases. Sepsis is a life-threatening organ dysfunction caused by the dysregulation of the response to infection. Currently, no specific drug that can alleviate or even cure sepsis in a comprehensive and multi-level manner has been found. DcR3 is closely related to sepsis and considerably upregulated in the serum of those patients, and its upregulation is positively correlated with the severity of sepsis and can be a potential biomarker for diagnosis. DcR3 alone or in combination with other markers has shown promising results in the early diagnosis of sepsis. Furthermore, DcR3 is a multipotent immunomodulator that can bind FasL, LIGHT, and TL1A through decoy action, and block downstream apoptosis and inflammatory signaling. It also regulates T-cell and macrophage differentiation and modulates immune status through non-decoy action; therefore, DcR3 could be a potential drug for the treatment of sepsis. The application of DcR3 in the treatment of a mouse model of sepsis also achieved good efficacy. Here, we introduce and discuss the progress in, and suggest novel ideas for, research regarding DcR3 in the diagnosis and treatment of sepsis.