Up-regulated CD38 by daphnetin alleviates lipopolysaccharide-induced lung injury via inhibiting MAPK/NF-κB/NLRP3 pathway.

BACKGROUND: Sepsis is a life-threatening organ dysfunction syndrome resulted from severe infection with high morbidity and mortality. Cluster of differentiation 38 (CD38) is a multifunctional type II transmembrane glycoprotein widely expressed on the surface of various immunocytes membranes that mediates host immune response to infection and plays an important role in many inflammatory diseases. Daphnetin (Daph), isolated from the daphne genus plant, is a natural coumarin derivative that possesses anti-inflammatory and anti-apoptotic effects. The current study aimed to investigate the role and mechanism of Daph in alleviating lipopolysaccharide (LPS)-induced septic lung injury, and to explore whether the protective effect of Daph in mice and cell models was related to CD38. METHODS: Firstly, network pharmacology analysis of Daph was performed. Secondly, LPS-induced septic lung injury in mice were treated with Daph or vehicle control respectively and then assessed for survival, pulmonary inflammation and pathological changes. Lastly, Mouse lung epithelial cells (MLE-12 cells) were transfected with CD38 shRNA plasmid or CD38 overexpressed plasmid, followed by LPS and Daph treatment. Cells were assessed for viability and transfection efficiency, inflammatory and signaling. RESULTS: Our results indicated that Daph treatment improved survival rate and alleviated pulmonary pathological damage of the sepsis mice, as well as reduced the excessive release of pro-inflammatory cytokines IL-1ß, IL-18, IL-6, iNOS and chemokines MCP-1 regulated by MAPK/NF-κB pathway in pulmonary injury. Daph treatment decreased Caspase-3 and Bax, increased Bcl-2, inhibited nucleotide-binding domain (NOD)-like receptor protein 3 (NLRP3) inflammasome-mediated pyroptosis in lung tissues of septic lung injury. Also, Daph treatment reduced the level of excessive inflammatory mediators, inhibited apoptosis and pyroptosis in MLE-12 cells. It is noteworthy that the protective effect of Daph on MLE-12 cells damage and death was assisted by the enhanced expression of CD38. CONCLUSIONS: Our results demonstrated that Daph offered a beneficial therapeutic effect for septic lung injury via the up-regulation of CD38 and inhibition of MAPK/NF-κB/NLRP3 pathway. Video Abstract.

CD38 deficiency up-regulated IL-1ß and MCP-1 through TLR4/ERK/NF-κB pathway in sepsis pulmonary injury.

As a disease with high mortality, many cytokines and signaling pathways are associated with sepsis. The pro-inflammatory cytokines and chemokines are participating in the pathogenesis of sepsis, especially in early stage. Moreover, the releases and expressions of cytokines are regulated by numerous signaling pathways, including TLR4/ERK pathway. But despite many studies have expounded the pathogenesis of sepsis and the regulation of cytokines in sepsis, how CD38 influence the expressions of related molecules in sepsis are still unknown. The aim of this study is illuminating the alteration of cytokines and signaling pathways in CD38-/- mice injected with Escherichia coli. Compared with WT mice, E. coli infection results in more severe pulmonary injuries and higher mRNA expressions of cytokines. Compared with E. coli infected WT mice, CD38 knockout leads to aggravated pulmonary injury, increased phosphorylated ERK1/2, p38 and NF-κB p65, and enhanced levels of IL-1ß, iNOS and MCP-1. While compared with E. coli infected CD38-/- mice, TLR4 mutation results in alleviated pulmonary injury, down-regulated phosphorylated ERK1/2 and NF-κB p65, and decreased expressions of IL-1ß and MCP-1. CD38 deficiency increased the expressions of IL-1ß andMCP-1 and aggravated pulmonary injury through TLR4/ERK/NF-κB pathway in sepsis.

TLR4-NLRP3-GSDMD-Mediated Pyroptosis Plays an Important Role in Aggravated Liver Injury of CD38-/- Sepsis Mice.

Clinically, severe bacterial infection can cause septicemia and multiple organ dysfunction syndrome, especially liver injury. CD38 is closely related to many inflammatory pathways, but its role in liver injury caused by bacterial infection remains unclear. The purpose of this study is to discuss the specific role of CD38 in bacterial liver injury. Eight-week-old male C57BL/6 mice (WT, CD38-/- and CD38-/-TLR4mut) were used and stimulated with Escherichia coli (ATCC25922) or PBS, intraperitoneally. After 3 hours of bacterial stimulation, serum was collected to detect ALT and AST concentration, and liver tissue was harvested for hematoxylin and eosin staining and bacterial culture. The mRNA expressions of TLR4, NLRP3, IL-1ß, IL-18, and GSDMD were quantitatively determined by RT-qPCR. The expressions of TLR4, MyD88, TRIF, NF-κB p65, NLRP3, GSDMD, and cytokines were detected by Western blot. The expression and localization of ERK1/2 were detected by immunohistochemistry and Western blot. The results showed that bacterial stimulation could upregulate the expression of inflammatory cytokines, leading to hepatic dysfunction. Moreover, bacterial stimulation of CD38-deficient mice can aggravate the inflammatory response, the expressions of TLR4, NF-κB, and ERK1/2 were significantly increased, and the biomarkers related to pyroptosis also manifested more obvious pyroptosis. However, TLR4 mutation significantly alleviated inflammation and pyroptosis in the liver caused by bacteria, on the basis of CD38 deficiency. Overall, CD38 knockout exacerbates bacteria-induced liver damage through TLR4-NLRP3-GSDMD-mediated pyroptosis.

[SWOT analysis of clinical application of modified early warning score].

OBJECTIVE: The modified early warning score (MEWS), as a rapid assessment and early warning scoring tool, has been widely used in patients in China, which can help nurses to identify potentially critical patients early, but not in all clinical fields. Through the retrieval of the relevant literature of the clinical application of the MEWS in Wanfang Medical Database from 2011 to 2018, the SWOT analysis was used in this paper [strength (S), weakness (W), opportunities (O) and threats (T)] methods, to systematically analyze the advantages, problems existence, implementation opportunities and challenges in the clinical application of the MEWS in our country. The purpose of this study was to obtain the best cut-off value of MEWS in different diseases and to formulate standard early-warning intervention measures for MEWS, which may provide reference for clinical workers to carry out relevant research.

CD38 Deficiency Downregulates the Onset and Pathogenesis of Collagen-Induced Arthritis through the NF-κB Pathway.

AIM: The RelB gene plays an important role in guiding the progression of arthritis. We have previously demonstrated that the expression of the RelB gene is decreased significantly in bone marrow DCs of CD38-/- mice. In this study, we demonstrate that the cluster of the differentiation (CD38) gene could be a potentially therapeutic target for autoimmune arthritis. METHOD: Collagen-induced arthritis (CIA) models were generated with both the wild-type (WT) C57BL/6 and CD38-/- mice. The expression of the RelB gene and maturation of bone marrow-derived dendritic cells (DCs) from the WT and CD38-/- mice were detected. Antigen-specific T cell responses, joint damage, and expression of proinflammatory cytokines were assessed. The effects of the Nuclear Factor Kappa B (NF-κB) transcription factor and its mechanisms were characterized. RESULTS: We demonstrated that in CD38-/- mice, the expression of the RelB gene and major histocompatibility complex II (MHC II) was decreased, accompanied with the inhibited T cell reaction in a mixed lymphocyte reaction (MLR) in bone marrow-derived DCs. Compared to the serious degeneration of the cartilage and the enlarged gap of the cavum articular in WT CIA mice, joint pathological changes of the CD38-/- CIA mice revealed marked attenuation, while the joint structures were well preserved. The preserved effects were observed by the inhibition of proinflammatory cytokines and promotion of anti-inflammatory cytokines. Furthermore, decreased phosphorylation of NF-κB was also observed in CD38-/- CIA mice. CONCLUSION: We demonstrate that CD38 could regulate CIA through NF-κB and this regulatory molecule could be a novel target for the treatment of autoimmune inflammatory joint disease.

Increased TLR4 Expression Aggravates Sepsis by Promoting IFN-γ Expression in CD38-/- Mice.

Gram-negative bacterial sepsis accounts for up to 50% worldwide sepsis that causes hospital mortality. Acute kidney injury (AKI), a common complication of Gram-negative bacterial sepsis, is caused by Toll-like receptor 4 (TLR4) activation. Lipopolysaccharide (LPS) is an endotoxin in Gram-negative bacteria and is recognized specifically by TLR4, which initiates innate immune response. Also, TLR4 signaling pathway activation is essential in response to LPS infection. CD38 is one of the well-known regulators of innate immunity, whose dysregulation contributes to sepsis. Many studies have proven that an attenuated Gram-positive bacterium induces sepsis in a CD38-blocking model. However, the pathogenesis of Gram-negative bacteria-induced sepsis in a CD38-/- mouse model remains unclear. The aim of this study is to investigate whether kidney injury is still attenuated in a LPS-induced CD38-/- sepsis model and identify the potential mechanism. We assess the severity of kidney injury related to proinflammatory cytokine expressions (IFN-γ, TNF-α, IL-1ß, and IL-6) in WT and CD38-/- mice. Our results showed more aggravated kidney damage in CD38-/- mice than in WT mice, accompanied with an increase of proinflammatory cytokine expression. In addition, compared with CD38-/-TLR4mut mice, we found an increase of TLR4 expression and mRNA expression of these cytokines in the kidney of CD38-/- mice, although only increased IFN-γ level was detected in the serum. Taken together, these results demonstrated that an increased TLR4 expression in CD38-/- mice could contribute to the aggravation of AKI through boosting of the production of IFN-γ.