detecting-migration-and-infiltration-of-neutrophils-in-mice

Detecting Migration and Infiltration of Neutrophils in Mice

Neutrophils are a major member of the innate immune system and play pivotal roles in host defense against pathogens and pathologic inflammatory reactions. ...

Beijing University of Chinese Medicine

Rheumatoid arthritis (RA) is a chronic autoimmune disease characterized by cellular infiltration into the joints and cartilage destruction. Neutrophils play a crucial role in the pathogenesis of RA. Triptolide (TP) is a bioactive compound derived from Tripterygium wilfordii Hook F, which has been used in folk medicine as a treatment for a variety of inflammatory disorders, including RA, for many centuries. Previous studies have shown that TP possesses anti-arthritic activity. However, the anti-arthritic mechanism of TP remains to be fully defined. In the present study, we used the adjuvant-induced arthritis (AA) murine model of RA to investigate the impact of TP on RA and neutrophil function. TP alleviated AA by reducing neutrophil recruitment and suppressing the expression of interleukin-6 and tumour necrosis factor-α in vivo. TP also suppressed the expression of pro-inflammatory cytokines in neutrophils, promoted neutrophil apoptosis and inhibited the migration, NETosis and autophagy of neutrophils in vitro. Based on our findings, TP effectively ameliorates RA by down-regulating neutrophil inflammatory functions, indicating that TP represents a potential therapeutic agent for RA.

Triptolide inhibits the inflammatory activities of neutrophils to ameliorate chronic arthritis.

Domestication of a transposon (a DNA sequence that can change its position in a genome) to give rise to the RAG1-RAG2 recombinase (RAG) and V(D)J recombination, which produces the diverse repertoire of antibodies and T cell receptors, was a pivotal event in the evolution of the adaptive immune system of jawed vertebrates. The evolutionary adaptations that transformed the ancestral RAG transposase into a RAG recombinase with appropriately regulated DNA cleavage and transposition activities are not understood. Here, beginning with cryo-electron microscopy structures of the amphioxus ProtoRAG transposase (an evolutionary relative of RAG), we identify amino acid residues and domains the acquisition or loss of which underpins the propensity of RAG for coupled cleavage, its preference for asymmetric DNA substrates and its inability to perform transposition in cells. In particular, we identify two adaptations specific to jawed-vertebrates-arginine 848 in RAG1 and an acidic region in RAG2-that together suppress RAG-mediated transposition more than 1,000-fold. Our findings reveal a two-tiered mechanism for the suppression of RAG-mediated transposition, illuminate the evolution of V(D)J recombination and provide insight into the principles that govern the molecular domestication of transposons.

Transposon molecular domestication and the evolution of the RAG recombinase.

Rheumatoid arthritis (RA) is a chronic, systemic, synovitis-based inflammatory disease with unknown etiology. Neutrophils play important roles in the pathogenesis of RA. Apoptosis and NETosis of neutrophils are two major mechanisms of programmed cell death that differ in their morphological characteristics and effects on the immune system. In rheumatoid arthritis, delayed neutrophil apoptosis amplifies the inflammatory response; and massive release of NETs and their components may cause tissue damage and provide self-antigens. Emodin is a natural anthraquinone derivative that occurs in many widely used Chinese medicinal herbs. In this study, we evaluated the effect of emodin on a murine adjuvant-induced arthritis (AA) model of RA in vivo and on neutrophil apoptosis and NETosis in vitro. Our results show that emodin alleviated AA by reducing neutrophil infiltration and proinflammatory cytokine (interleukin-6, interferon-gamma and tumor necrosis factor-α) release. Emodin promoted apoptosis and inhibited autophagy and NETosis in neutrophils. These findings indicate that emodin represents a potential therapeutic agent for RA.

Emodin ameliorates rheumatoid arthritis by promoting neutrophil apoptosis and inhibiting neutrophil extracellular trap formation.

Rheumatoid arthritis (RA) is a chronic inflammatory disease characterized by symmetric polyarthritis with swelling and pain at synovial joints. In RA patients, delayed neutrophil apoptosis amplifies the inflammatory response and massively released neutrophil extracellular traps (NETs) induce tissue damage and provide self-antigens. Andrographolide (AD) is the major active labdane diterpenoid derived from , which has multiple pharmacological effects, including hepatoprotection, anti-angiogenesis, anti-thrombosis, and anti-inflammation. In the present study, we investigated the effect of AD on an adjuvant-induced arthritis (AA) murine model of RA and found that AD alleviated murine arthritis by reducing neutrophil infiltration and NETosis in the ankle joints and relieved the systematic inflammation. In vitro experiments showed that AD accelerated the apoptosis of lipopolysaccharide-activated neutrophils and inhibited autophagy-dependent extracellular traps formation of neutrophils. These findings suggest that AD has considerable potential for RA therapy.

Andrographolide Ameliorates Rheumatoid Arthritis by Regulating the Apoptosis-NETosis Balance of Neutrophils.

Bioactive compounds from medicinal plants with anti-inflammatory and immunosuppressive effects have been emerging as important sources of drugs for the treatment of inflammatory disorders. Triptolide, a diterpene triepoxide, is a pharmacologically active compound isolated from  Hook F (TwHF) that is used as a remedy for inflammatory and autoimmune diseases. As the most promising bioactive compound obtained from TwHF, triptolide has attracted considerable interest recently, especially for its potent anti-inflammatory and immunosuppressive activities. Over the past few years, an increasing number of studies have been published emphasizing the value of triptolide in the treatment of diverse inflammatory disorders. Here, we systematically review the mechanism of action and the therapeutic properties of triptolide in various inflammatory diseases according to different systematic organs, including lupus nephritis, inflammatory bowel disease, asthma, and rheumatoid arthritis with pubmed and Embase. Based on this review, potential research strategies might contribute to the clinical application of triptolide in the future.

Article	Year
Triptolide inhibits the inflammatory activities of neutrophils to ameliorate chronic arthritis. Molecular immunology\| PubMed ID: 30007231	2018
Transposon molecular domestication and the evolution of the RAG recombinase. Nature\| PubMed ID: 30971819	2019
Emodin ameliorates rheumatoid arthritis by promoting neutrophil apoptosis and inhibiting neutrophil extracellular trap formation. Molecular immunology\| PubMed ID: 31176198	2019
Andrographolide Ameliorates Rheumatoid Arthritis by Regulating the Apoptosis-NETosis Balance of Neutrophils. International journal of molecular sciences\| PubMed ID: 31614480	2019
Application and Mechanisms of Triptolide in the Treatment of Inflammatory Diseases-A Review. Frontiers in pharmacology\| PubMed ID: 31866868	2019

Qingyi Lu

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