The cyclic GMP-AMP (cGAMP) synthase (cGAS) has been identified as a cytosolic double stranded DNA sensor that plays a pivotal role in the type I interferon and inflammation responses via the STING-dependent signaling pathway. In the past several years, a growing body of evidence has revealed that cGAS is also localized in the nucleus where it is associated with distinct nuclear substructures such as nucleosomes, DNA replication forks, the double-stranded breaks, and centromeres, suggesting that cGAS may have other functions in addition to its role in DNA sensing. However, while the innate immune function of cGAS is well established, the non-canonical nuclear function of cGAS remains poorly understood. Here, we review our current understanding of the complex nature of nuclear cGAS and point to open questions on the novel roles and the mechanisms of action of this protein as a key regulator of cell nuclear function, beyond its well-established role in dsDNA sensing and innate immune response.
Cell Nucleus/immunology* ; Humans ; Immunity, Innate ; Nucleotidyltransferases/immunology* ; Signal Transduction/immunology*

OBJECTIVE: This study aimed to investigate the effects of caprylic acid (C8:0) on lipid metabolism and inflammation, and examine the mechanisms underlying these effects in mice and cells. METHODS: Fifty-six 6-week-old male C57BL/6J mice were randomly allocated to four groups fed a high-fat diet (HFD) without or with 2% C8:0, palmitic acid (C16:0) or eicosapentaenoic acid (EPA). RAW246.7 cells were randomly divided into five groups: normal, lipopolysaccharide (LPS), LPS+C8:0, LPS+EPA and LPS+cAMP. The serum lipid profiles, inflammatory biomolecules, and ABCA1 and JAK2/STAT3 mRNA and protein expression were measured. RESULTS: C8:0 decreased TC and LDL-C, and increased the HDL-C/LDL-C ratio after injection of LPS. Without LPS, it decreased TC in mice ( P < 0.05). Moreover, C8:0 decreased the inflammatory response after LPS treatment in both mice and cells ( P < 0.05). Mechanistic investigations in C57BL/6J mouse aortas after injection of LPS indicated that C8:0 resulted in higher ABCA1 and JAK2/STAT3 expression than that with HFD, C16:0 and EPA, and resulted in lower TNF-α, NF-κB mRNA expression than that with HFD ( P < 0.05). In RAW 264.7 cells, C8:0 resulted in lower expression of pNF-κBP65 than that in the LPS group, and higher protein expression of ABCA1, p-JAK2 and p-STAT3 than that in the LPS and LPS+cAMP groups ( P < 0.05). CONCLUSION Our studies demonstrated that C8:0 may play an important role in lipid metabolism and the inflammatory response, and the mechanism may be associated with ABCA1 and the p-JAK2/p-STAT3 signaling pathway.
ATP Binding Cassette Transporter 1/immunology* ; Animals ; Caprylates/chemistry* ; Cholesterol/metabolism* ; Diet, High-Fat/adverse effects* ; Humans ; Inflammation/metabolism* ; Janus Kinase 2/immunology* ; Lipid Metabolism/drug effects* ; Macrophages/immunology* ; Male ; Mice ; Mice, Inbred C57BL ; RAW 264.7 Cells ; STAT3 Transcription Factor/immunology* ; Signal Transduction

Animals ; Arthritis, Experimental ; Collagen Type II ; Male ; Mice ; Mice, Inbred DBA ; Receptors, Adrenergic, alpha-1 ; Signal Transduction ; T-Lymphocytes, Regulatory/immunology*

In this research, we studied the formation of Drosophila melanogaster FADD (Fas-associated death domain-containing protein) amyloid fiber and its influence on signal transduction in IMD (Immune deficiency) signaling pathway to better understand the regulation mechanism of Drosophila innate immune signaling pathway, which will provide reference for the immune regulation in other species. First, we purified dFADD protein expressed in Escherichia coli and performed Sulfur flavin T binding and transmission electron microscopy to identify the dFADD amyloid fibers formed in vitro. Then we investigated the formation of dFADD polymers in S2 cells using SDD-AGE and confocal microscope. We also constructed dFADD mutants to find out which domain is essential to fiber formation and its effect on IMD signal transduction. Our results revealed that dFADD could be polymerized to form amyloid fiber polymers in vitro and inside the cells. Formation of fibers relies on DED (Death-effector domain) domain of dFADD, since DED domain-deleted mutant existed as a monomer. Dual luciferase reporter assay showed that intact DED domain was required for the induction of downstream antimicrobial peptides, indicating that fiber formation was the key to IMD signal transduction. Our study revealed the role of dFADD in mediating the cascade between IMD and Dredd in the IMD signaling pathway by forming amyloid fibers, suggesting an evolutionarily conserved regulatory mechanism of innate immune signaling pathway.
Animals ; Drosophila Proteins ; biosynthesis ; immunology ; Drosophila melanogaster ; immunology ; Fas-Associated Death Domain Protein ; biosynthesis ; immunology ; Immunity, Innate ; immunology ; Signal Transduction

Tripartite motif (TRIM) family proteins are important effectors of innate immunity against viral infections. Here we identified TRIM35 as a regulator of TRAF3 activation. Deficiency in or inhibition of TRIM35 suppressed the production of type I interferon (IFN) in response to viral infection. Trim35-deficient mice were more susceptible to influenza A virus (IAV) infection than were wild-type mice. TRIM35 promoted the RIG-I-mediated signaling by catalyzing Lys63-linked polyubiquitination of TRAF3 and the subsequent formation of a signaling complex with VISA and TBK1. IAV PB2 polymerase countered the innate antiviral immune response by impeding the Lys63-linked polyubiquitination and activation of TRAF3. TRIM35 mediated Lys48-linked polyubiquitination and proteasomal degradation of IAV PB2, thereby antagonizing its suppression of TRAF3 activation. Our in vitro and in vivo findings thus reveal novel roles of TRIM35, through catalyzing Lys63- or Lys48-linked polyubiquitination, in RIG-I antiviral immunity and mechanism of defense against IAV infection.
A549 Cells ; Animals ; Apoptosis Regulatory Proteins/immunology* ; DEAD Box Protein 58/immunology* ; Dogs ; HEK293 Cells ; Humans ; Influenza A Virus, H1N1 Subtype/immunology* ; Madin Darby Canine Kidney Cells ; Mice ; Mice, Knockout ; Orthomyxoviridae Infections/pathology* ; Proteolysis ; RAW 264.7 Cells ; Signal Transduction/immunology* ; THP-1 Cells ; TNF Receptor-Associated Factor 3/immunology* ; Ubiquitination/immunology* ; Viral Proteins/immunology*

The aim of this paper was to study the influence of triptolide in the immune response pathways of acquired immune deficiency syndrome( AIDS). Target proteins of triptolide and related genes of AIDS were searched in PubChem and Gene databases on line. Molecular networks and canonical pathways comparison analyses were performed by bioinformatics software( IPA). There were 15 targets proteins of triptolide and 258 related genes of AIDS. Close biological relationships of molecules of triptolide and AIDS were established by networks analysis. There were 21 common immune response pathways of triptolide and AIDS,including neuroinflammation signaling pathway,Th1 and Th2 activation pathway and role of pattern recognition receptors in recognition of bacteria and viruses. Triptolide stimulated immune response pathways by the main molecules of IFNγ,JAK2,NOD1,PTGS2,RORC. IFNγ is the focus nodes of triptolide and AIDS,and regulates genes of AIDS directly or indirectly. Triptolide may against AIDS by regulating molecules IFNγ in immune response pathways.
Acquired Immunodeficiency Syndrome ; drug therapy ; immunology ; Computational Biology ; Diterpenes ; pharmacology ; Epoxy Compounds ; pharmacology ; Gene Regulatory Networks ; Humans ; Interferon-gamma ; genetics ; Phenanthrenes ; pharmacology ; Receptors, Pattern Recognition ; immunology ; Signal Transduction ; T-Lymphocytes ; immunology

Macrophages show significant heterogeneity in function and phenotype, which could shift into different populations of cells in response to exposure to various micro-environmental signals. These changes, also termed as macrophage polarization, of which play an important role in the pathogenesis of many diseases. Numerous studies have proved that Hesperidin (HDN), a traditional Chinese medicine, extracted from fruit peels of the genus citrus, play key roles in anti-inflammation, anti-tumor, anti-oxidant and so on. However, the role of HDN in macrophage polarization has never been reported. Additional, because of its poor water solubility and bioavailability. Our laboratory had synthesized many hesperidin derivatives. Among them, hesperidin derivatives-12 (HDND-12) has better water solubility and bioavailability. So, we evaluated the role of HDND-12 in macrophage polarization in the present study. The results showed that the expression of Arginase-1 (Arg-1), interleukin-10 (IL-10), transforming growth factor β (TGF-β) were up-regulated by HDND-12, whereas the expression of inducible Nitric Oxide Synthase (iNOS) was down-regulated in LPS- and IFN-γ-treated (M1) RAW264.7 cells. Moreover, the expression of p-JAK2 and p-STAT3 were significantly decreased after stimulation with HDND-12 in M1-like macrophages. More importantly, when we taken AG490 (inhibitor of JAK2/STAT3 signaling), the protein levels of iNOS were significantly reduced in AG490 stimulation group compare with control in LPS, IFN-γ and HDND-12 stimulation cells. Taken together, these findings indicated that HDND-12 could prevent polarization toward M1-like macrophages, at least in part, through modulating JAK2/STAT3 pathway.
Animals ; Cytokines ; genetics ; metabolism ; Enzyme Inhibitors ; pharmacology ; Gene Expression Regulation ; drug effects ; Hesperidin ; chemistry ; pharmacology ; Inflammation ; genetics ; metabolism ; Janus Kinase 2 ; antagonists & inhibitors ; metabolism ; Macrophages ; drug effects ; immunology ; metabolism ; Medicine, Chinese Traditional ; Mice ; Molecular Structure ; Phosphorylation ; drug effects ; RAW 264.7 Cells ; STAT3 Transcription Factor ; antagonists & inhibitors ; metabolism ; Signal Transduction ; drug effects

To understand the effects of Lactobacillus rhamnosus GG (ATCC 53103) on intestinal barrier function in pre-weaning piglets under normal conditions, twenty-four newborn littermate piglets were randomly divided into two groups. Piglets in the control group were orally administered with 2 mL 0.1 g/mL sterilized skim milk while the treatment group was administered the same volume of sterilized skim milk with the addition of viable L. rhamnosus at the 1st, 3rd, and 5th days after birth. The feeding trial was conducted for 25 d. Results showed that piglets in the L. rhamnosus group exhibited increased weaning weight and average daily weight gain, whereas diarrhea incidence was decreased. The bacterial abundance and composition of cecal contents, especially Firmicutes, Bacteroidetes, and Fusobacteria, were altered by probiotic treatment. In addition, L. rhamnosus increased the jejunal permeability and promoted the immunologic barrier through regulating antimicrobial peptides, cytokines, and chemokines via Toll-like receptors. Our findings indicate that oral administration of L. rhamnosus GG to newborn piglets is beneficial for intestinal health of pre-weaning piglets by improving the biological, physical, and immunologic barriers of intestinal mucosa.
Administration, Oral ; Animals ; Animals, Newborn ; Cytokines/genetics* ; Female ; Gastrointestinal Microbiome ; Immunity, Innate ; Intestinal Mucosa/immunology* ; Lacticaseibacillus rhamnosus ; Male ; Probiotics/administration & dosage* ; Signal Transduction ; Swine ; Weaning

Streptococcus mutans (S. mutans), a major aetiologic agent of dental caries, is involved in systemic diseases, such as bacterial endocarditis, if it enters the bloodstream through temporary bacteraemia. Interleukin (IL)-1β, a proinflammatory cytokine, is related to the host defences against pathogens, and its synthesis, maturation, and secretion are tightly regulated by the activation of the inflammasome, an inflammatory signalling complex. This study examined the signalling mechanism of IL-1β secretion and the inflammasome pathway induced by S. mutans to explain the molecular mechanism through which systemic infection by oral streptococci can occur. After infection of THP-1 cells with S. mutans, the expression of inflammasome components was detected using various methods. S. mutans induced IL-1β secretion via caspase-1 activation, and S. mutans-induced IL-1β secretion required absent in melanoma (AIM2), NLR family pyrin domain-containing 3 (NLRP3) and NLR family CARD domain-containing 4 (NLRC4) inflammasome activation. In particular, the S. mutans-induced NLRP3 inflammasome was mediated by adenosine triphosphate (ATP) release, potassium depletion and lysosomal damage. Our study provides novel insight into the innate immune response against S. mutans infection.
Blotting, Western ; CARD Signaling Adaptor Proteins ; immunology ; Calcium-Binding Proteins ; immunology ; Caspase 1 ; immunology ; DNA-Binding Proteins ; immunology ; Enzyme-Linked Immunosorbent Assay ; Humans ; Immunity, Innate ; Inflammasomes ; immunology ; Interleukin-1beta ; immunology ; Macrophages ; immunology ; NLR Family, Pyrin Domain-Containing 3 Protein ; immunology ; Signal Transduction ; Streptococcus mutans ; immunology ; Tumor Necrosis Factor-alpha ; immunology

The pathogenesis of allergic rhinitis(AR)is extremely complex.In recent years,a variety of allergens and other complexes have been developed to induce a series of signal transduction mechanisms by activating mast cells.Intracellular media release(mast cells,MCs)play an important role in the pathogenesis of AR.In this paper,we reviewed the progress of mast cells in the pathogenesis of allergic rhinitis in recent years in order to further understand its role in the pathogenesis of allergic rhinitis and provide new ideas on the therapeutic target for allergic rhinitis.
Allergens ; Cell Count ; Humans ; Mast Cells ; Rhinitis, Allergic ; immunology ; Signal Transduction