Effectiveness of Huai Qi Huang Granules on Juvenile Collagen-induced Arthritis and Its Influence on Pyroptosis Pathway in Synovial Tissue.

Huai Qi Huang (HQH) exerts great effects in clinic, such as anti-inflammation, immune-regulation, anti-cancer, and so on. However, the mechanism by which HQH protects juvenile idiopathic arthritis (JIA) is obscure. Thus, we explored deeply the protective mechanisms in juvenile collagen-induced arthritis (CIA) rat model. Pyroptosis is Gasdermin D (GSDMD)-dependent programmed cell death, involved in many diseases, such as sepsis. We investigated whether GSDMD-induced pyroptosis take part in mechanisms of juvenile CIA arthritis. Juvenile Wistar rats (3-4 weeks) were injected intradermally with fully emulsified bovine type II collagen and complete Freund's adjuvant to establish CIA rat models. Later, the CIA rats received oral administration of HQH (4.16 g/kg) once a day from the day 21 of modeling, with the treatment lasting for 28 days. Varieties of indicators were measured for evaluation of anti-inflammation effect of HQH, including hind paw swelling, arthritis scores, micro CT, and histopathological changes and the level of pro-inflammatory cytokines in the serum, including tumor necrosis factor alpha (TNF-±) and interleukin-18 (IL-18). The expression of GSDMD and caspase-1 in the joint synovial tissues was detected. The results demonstrated that the expression of the pyroptotic protein GSDMD and its upstream caspase-1 was significantly increased in the synovial tissues of CIA rats. The treatment of HQH ameliorated the symptoms in CIA rats, reduced levels of pro-inflammatory cytokines and hind paw swelling, down-regulated the expression of GDSMD and caspase-1. GSDMD-induced pyroptosis participated in the pathogenesis of CIA rats. The study supported that HQH can effectively improve joints inflammation of juvenile collagen-induced arthritis rats by inhibiting pyroptosis pathway in the joint synovial tissues.

The Immuno-Enhancement Effects of Tubiechong (Eupolyphaga sinensis) Lyophilized Powder in Cyclophosphamide-Induced Immunosuppressed Mice.

Tubiechong (Eupolyphaga sinensis) is an important material used in traditional Chinese medicine (TCM). However, the immunoregulation effects of E. sinensis Lyophilized Powder (ESL) are unclear. The in vivo study thus designed to elucidate the immuno-enhancement effects of ESL in immunosuppressed mice induced by cyclophosphamide (CTX). Mice were treated with three doses of ESL (0.5, 1.0 and 2.0 g/kg). Compared with model group, ESL notably increased the immune organ index, mononuclear macrophages function and the level of nature killer cell (NK) (p < 0.05 or p < 0.01), delayed type hypersensitivity (DTH) was also improved (p < 0.05). The level of superoxide dismutase (SOD) and catalase (CAT) were enhanced (p < 0.05), while malonyldialdehyde (MDA) and nitrogen monoxide (NO) were reduced (p < 0.05 or p < 0.01). Meanwhile, cluster determinant (CD)3+ T cell, CD4+ T cell and CD4+/CD8+ ratio were increased (p < 0.01). The cytokines secretion such as interleukin (IL)-2 and tumor necrosis factor alpha (TNF-α) were notably increased (p < 0.05 or p < 0.01), and IL-6 and IL-16 were also enhanced (p < 0.05). Furthermore, ESL significantly inhibited the phosphorylation of c-Jun N-terminal kinase (JNK), down-regulated the expression of Bcl-2 associated X protein (Bax), up-regulated the B cell lymphoma-2 protein (Bcl-2) expression and decreased the Bax/Bcl-2 ratio in spleen tissues (p < 0.05). In brief, all these findings suggest that ESL could effectively improve immune functions via modulating oxidative systems and innate immune cells. Abbreviations: TCM: Traditional Chinese Medicine; ESL: Eupolyphaga sinensis Lyophilized Powder; CCl4: Carbon tetrachloride; ERK: Extracellular regulated protein kinases; CTX: Cyclophosphamide; DTH: Delayed type hypersensitivity; SOD: Superoxide dismutase; CAT: Catalase; MDA: Malonyldialdehyde; NO: Nitrogen monoxide; NK: Nature killer cell; CD: Cluster determinant interleukin; TNF-α: Tumor Necrosis Factor alpha; JNK: c-Jun N-terminal kinase; Bax: Bcl-2 associated X protein; Bcl-2: B cell lymphoma-2 protein; Th1: Type-1 helper; Th2: Type-2 helper; FAMEs: Fatty acid methyl esters; DNFB: 2,4 - Dinitrofluorobenzene; ELISA: Enzyme-linked immuno sorbent assay; MAPK: Mitogen activated protein kinase; Cyt-c: Cytochrome c; SCFAs: Short-chain fatty acids; SDS-PAGE: Sodium dodecyl sulfate polyacrylamide gel electrophoresis.

Interleukin-18 diagnostically distinguishes and pathogenically promotes human and murine macrophage activation syndrome.

Hemophagocytic lymphohistiocytosis (HLH) and macrophage activation syndrome (MAS) are life-threatening hyperferritinemic systemic inflammatory disorders. Although profound cytotoxic impairment causes familial HLH (fHLH), the mechanisms driving non-fHLH and MAS are largely unknown. MAS occurs in patients with suspected rheumatic disease, but the mechanistic basis for its distinction is unclear. Recently, a syndrome of recurrent MAS with infantile enterocolitis caused by NLRC4 inflammasome hyperactivity highlighted the potential importance of interleukin-18 (IL-18). We tested this association in hyperferritinemic and autoinflammatory patients and found a dramatic correlation of MAS risk with chronic (sometimes lifelong) elevation of mature IL-18, particularly with IL-18 unbound by IL-18 binding protein, or free IL-18. In a mouse engineered to carry a disease-causing germ line NLRC4T337S mutation, we observed inflammasome-dependent, chronic IL-18 elevation. Surprisingly, this NLRC4T337S-induced systemic IL-18 elevation derived entirely from intestinal epithelia. NLRC4T337S intestines were histologically normal but showed increased epithelial turnover and upregulation of interferon-γ-induced genes. Assessing cellular and tissue expression, classical inflammasome components such as Il1b, Nlrp3, and Mefv predominated in neutrophils, whereas Nlrc4 and Il18 were distinctly epithelial. Demonstrating the importance of free IL-18, Il18 transgenic mice exhibited free IL-18 elevation and more severe experimental MAS. NLRC4T337S mice, whose free IL-18 levels were normal, did not. Thus, we describe a unique connection between MAS risk and chronic IL-18, identify epithelial inflammasome hyperactivity as a potential source, and demonstrate the pathogenicity of free IL-18. These data suggest an IL-18-driven pathway, complementary to the cytotoxic impairment of fHLH, with potential as a distinguishing biomarker and therapeutic target in MAS.

Selenium Deficiency Induces Autophagy in Immune Organs of Chickens.

The aim of the present study was to investigate the effects of selenium (Se) deficiency on autophagy-related genes and on ultrastructural changes in the spleen, bursa of Fabricius, and thymus of chickens. The Se deficiency group was fed a basal diet containing Se at 0.033 mg/kg and the control group was fed the same basal diet containing Se at 0.15 mg/kg. The messenger RNA (mRNA) levels of the autophagy genes microtubule-associated protein 1 light chain 3 (LC3)-I, LC3-II, Beclin 1, dynein, autophagy associated gene 5 (ATG5), and target of rapamycin complex 1 (TORC1) were assessed using real-time qPCR. The protein levels of LC3-II, Beclin 1, and dynein were investigated using western blot analysis. Furthermore, the ultrastructure was observed using an electron microscope. The results indicated that spleen mRNA levels of LC3-I, LC3-II, Beclin 1, dynein, ATG5, and TORC1 and the protein levels of LC3-II, Beclin 1, and dynein were increased in the Se deficiency group compared with the control group. In the bursa of Fabricius, the mRNA levels of LC3-I, LC3-II, Beclin 1, dynein, ATG5, and TORC1 and the protein levels of Beclin 1 and dynein were increased; furthermore, the protein level of LC3-II was decreased in the Se deficiency group compared to the control group. In the thymus, the mRNA levels of LC3-I, Beclin 1, and ATG5 increased; the levels of LC3-II, dynein, and TORC1 were decreased; the protein level of Beclin 1 increased; and the levels of LC3-II and dynein decreased in the Se deficiency group compared to those in the control group. Further cellular morphological changes, such as autophagy vacuoles, autolysosomes, and lysosomal degradation, were observed in the spleen, bursa of Fabricius, and thymus of the Se-deficiency group. In summary, Se deficiency caused changes in autophagy-related genes, which increased the autophagic process and also caused structural damages to the immune organs of chickens.

Inflammasomes Coordinate Pyroptosis and Natural Killer Cell Cytotoxicity to Clear Infection by a Ubiquitous Environmental Bacterium.

Defective neutrophils in patients with chronic granulomatous disease (CGD) cause susceptibility to extracellular and intracellular infections. Microbes must first be ejected from intracellular niches to expose them to neutrophil attack, so we hypothesized that inflammasomes detect certain CGD pathogens upstream of neutrophil killing. Here, we identified one such ubiquitous environmental bacterium, Chromobacterium violaceum, whose extreme virulence was fully counteracted by the NLRC4 inflammasome. Caspase-1 protected via two parallel pathways that eliminated intracellular replication niches. Pyroptosis was the primary bacterial clearance mechanism in the spleen, but both pyroptosis and interleukin-18 (IL-18)-driven natural killer (NK) cell responses were required for liver defense. NK cells cleared hepatocyte replication niches via perforin-dependent cytotoxicity, whereas interferon-γ was not required. These insights suggested a therapeutic approach: exogenous IL-18 restored perforin-dependent cytotoxicity during infection by the inflammasome-evasive bacterium Listeria monocytogenes. Therefore, inflammasomes can trigger complementary programmed cell death mechanisms, directing sterilizing immunity against intracellular bacterial pathogens.

Cholera toxin, and the related nontoxic adjuvants mmCT and dmLT, promote human Th17 responses via cyclic AMP-protein kinase A and inflammasome-dependent IL-1 signaling.

We have examined the molecular pathways involved in the adjuvant action of cholera toxin (CT) and two novel nontoxic molecules, multiple-mutated CT (mmCT) and double-mutant heat-labile toxin (dmLT) on human T cell responses. Human PBMCs or isolated monocytes were stimulated in vitro with CT, mmCT, or dmLT plus a polyclonal stimulus (staphylococcal enterotoxin B) or specific bacterial Ags, and effects on expression of cytokines and signaling molecules were determined. CT, mmCT, and dmLT strongly enhanced IL-17A and to a lesser extent IL-13 responses, but had little effect on IFN-γ production or cell proliferation. Intracellular cytokine staining revealed that the enhanced IL-17A production was largely confined to CD4(+) T cells and coculture experiments showed that the IL-17A promotion was effectively induced by adjuvant-treated monocytes. Relative to CT, mmCT and dmLT induced at least 100-fold lower levels of cAMP, yet this cAMP was enough and essential for the promotion of Th17 responses. Thus, inhibition of cAMP-dependent protein kinase A was abolished, and stimulation with a cAMP analog mimicked the adjuvant effect. Furthermore, CT, mmCT, and dmLT induced IL-1ß production and caspase-1 activation in monocytes, which was associated with increased expression of key proinflammatory and inflammasome-related genes, including NLRP1, NLRP3, and NLRC4. Inflammasome inhibition with a specific caspase-1 inhibitor, or blocking of IL-1 signaling by IL-1 receptor antagonist, abrogated the Th17-promoting effect. We conclude that CT, mmCT, and dmLT promote human Th17 responses via cAMP-dependent protein kinase A and caspase-1/inflammasome-dependent IL-1 signaling.

Inflammasomes.

Inflammasomes are large cytosolic multiprotein complexes that assemble in response to detection of infection- or stress-associated stimuli and lead to the activation of caspase-1-mediated inflammatory responses, including cleavage and unconventional secretion of the leaderless proinflammatory cytokines IL-1ß and IL-18, and initiation of an inflammatory form of cell death referred to as pyroptosis. Inflammasome activation can be induced by a wide variety of microbial pathogens and generally mediates host defense through activation of rapid inflammatory responses and restriction of pathogen replication. In addition to its role in defense against pathogens, recent studies have suggested that the inflammasome is also a critical regulator of the commensal microbiota in the intestine. Finally, inflammasomes have been widely implicated in the development and progression of various chronic diseases, such as gout, atherosclerosis, and metabolic syndrome. In this perspective, we discuss the role of inflammasomes in infectious and noninfectious inflammation and highlight areas of interest for future studies of inflammasomes in host defense and chronic disease.

Yin-Yang of costimulation: crucial controls of immune tolerance and function.

SUMMARY: In addition to signals from the T-cell receptor complex, it has been recognized for many years that a 'second' signal, most notably from CD28, is also important in T-cell activation. In the recent years, many new members of CD28 family as well as the molecules that share structural homology to CD28 ligands CD80 and CD86 have been discovered. Interestingly, some of these proteins function to dampen T-cell activation and regulate the induction of T-cell tolerance. Therefore, positive and negative costimulation are the two sides of the coin to fine tune T-cell receptor signaling to determine the outcome of T-cell receptor engagement-tolerance versus function.

Involvement of programmed death-ligand 2 (PD-L2) in the development of experimental allergic conjunctivitis in mice.

BACKGROUND/AIM: Involvement of programmed death-1 (PD-1) and its ligands has been demonstrated in experimental allergic airway disease. Here, the authors aimed to examine whether PD-1 and its ligands are involved in the development of experimental allergic conjunctivitis (EC) in mice. METHODS: EC was induced in Balb/c mice by active immunisation with short ragweed pollen (RW) in alum. 10 days later (day 10), the mice were challenged with eye drops containing RW. 24 hours after the challenge, conjunctivas, spleens, and sera were harvested for histological analysis, cytokine assays, and measurement of RW specific Ig levels. The actively immunised mice were treated with anti-PD-1, anti-PD-L1, anti-PD-L2 antibodies (Abs), or normal rat immunoglobulin G (nrIgG) during either the induction (day 0, 2, 4, 6, and 8) or the effector (2 hours before RW challenge on day 10) phase. RESULTS: Ab treatment during the induction phase did not affect eosinophil infiltration although immune responses were modulated. In contrast, treatment with anti-PD-L2 Ab, but not anti-PD-1 or anti-PD-L1 Ab, during the effector phase significantly increased eosinophil infiltration into the conjunctiva without affecting systemic immune responses. CONCLUSIONS: Similar to allergic airway inflammation, PD-L2 is involved in the development of EC during the effector phase but not the induction phase.

Garlic increases IL-10 and inhibits TNFalpha and IL-6 production in endotoxin-stimulated human placental explants.

Preeclampsia is a multisystem disorder manifest by hypertension after 20 weeks' gestation associated with end organ damage, usually proteinuria. The placenta is thought to be pivotal in the pathogenesis of the disease. Both the placenta and the maternal systemic response are characterised by heightened inflammation. Garlic has been shown to have anti-inflammatory and pro-apoptotic properties amongst others. It was hypothesised that treating placental explants with garlic may inhibit the production of inflammatory cytokines (interleukin-6 (IL-6) and tumour necrosis factor (TNFalpha)) and stimulate the production of anti-inflammatory cytokines (interleukin-10 (IL-10)) by the placental explants. Garlic, we hypothesised, would also stimulate apoptosis in the explants as measured by soluble TNF-related apoptosis-inducing ligand/Apo-2L (sTRAIL) production. Normal placental explants (n=5) and explants from women who had preeclampsia (n=4) were cultured in the presence of various garlic concentrations (10-1000 microg/mL). The lowest garlic concentration (10 microg/mL) increased the normal explant production of IL-10 by 29.2% (12.2, 57.5%; p<0.01) while inhibiting the production of IL-6 by 23.5% (8.9, 32.5%; p<0.01) (normal explants) and TNFalpha by 19.4% (4.5, 35.3%; p<0.05) (preeclamptic explants). Garlic resulted in an increase in IL-10 production at lower doses (normal explants only) and inhibition of the production of IL-10 at higher doses (normal and preeclamptic explants). Garlic also resulted in a dose-dependent reduction of IL-6 and TNFalpha. Initially there was no change in sTRAIL production; however, at the highest garlic concentrations there was a significant increase in production. We thus conclude that garlic may have an immunomodulatory effect on normal and preeclamptic placentas.