Recruitment of CCR6-expressing Th17 cells by CCL20 secreted from plasmin-stimulated macrophages

Human milk oligosaccharides differentially support gut barrier integrity and enhance Th1 and Th17 cell effector responses in vitro

Human milk oligosaccharides (HMOs) can modulate the intestinal barrier and regulate immune cells to favor the maturation of the infant intestinal tract and immune system, but the precise functions of individual HMOs are unclear. To determine the structure-dependent effects of individual HMOs (representing different structural classes) on the intestinal epithelium as well as innate and adaptive immune cells, we assessed fucosylated (2'FL and 3FL), sialylated (3'SL and 6'SL) and neutral non-fucosylated (LNT and LNT2) HMOs for their ability to support intestinal barrier integrity, to stimulate the secretion of chemokines from intestinal epithelial cells, and to modulate cytokine release from LPS-activated dendritic cells (DCs), M1 macrophages (MØs), and co-cultures with naïve CD4+ T cells. The fucosylated and neutral non-fucosylated HMOs increased barrier integrity and protected the barrier following an inflammatory insult but exerted minimal immunomodulatory activity. The sialylated HMOs enhanced the secretion of CXCL10, CCL20 and CXCL8 from intestinal epithelial cells, promoted the secretion of several cytokines (including IL-10, IL-12p70 and IL-23) from LPS-activated DCs and M1 MØs, and increased the secretion of IFN-γ and IL-17A from CD4+ T cells primed by LPS-activated DCs and MØs while reducing the secretion of IL-13. Thus, 3'SL and 6'SL supported Th1 and Th17 responses while reducing Th2 responses. Collectively, our data show that HMOs exert structure-dependent effects on the intestinal epithelium and possess immunomodulatory properties that confer benefits to infants and possibly also later in life.

Human Amniotic MSC Response in LPS-Stimulated Ascites from Patients with Cirrhosis: FOXO1 Gene and Th17 Activation in Enhanced Antibacterial Activation

Spontaneous bacterial peritonitis (SBP) is a severe complication in patients with decompensated liver cirrhosis and is commonly treated with broad spectrum antibiotics. However, the rise of antibiotic resistance requires alternative therapeutic strategies. As recently shown, human amnion-derived mesenchymal stem cells (hA-MSCs) are able, in vitro, to promote bacterial clearance and modulate the immune and inflammatory response in SBP. Our results highlight the upregulation of FOXO1, CXCL5, CXCL6, CCL20, and MAPK13 in hA-MSCs as well as the promotion of bacterial clearance, prompting a shift in the immune response toward a Th17 lymphocyte phenotype after 72 h treatment. In this study, we used an in vitro SBP model and employed omics techniques (next-generation sequencing) to investigate the mechanisms by which hA-MSCs modify the crosstalk between immune cells in LPS-stimulated ascitic fluid. We also validated the data obtained via qRT-PCR, cytofluorimetric analysis, and Luminex assay. These findings provide further support to the hope of using hA-MSCs for the prevention and treatment of infective diseases, such as SBP, offering a viable alternative to antibiotic therapy.

Factors regulating the differences in frequency of infiltration of Th17 and Treg of the blood-brain barrier

Controlling CD4+ immune cell infiltration of the brain is a leading aim in designing therapeutic strategies for a range of neuropathological disorders such as multiple sclerosis, Alzheimer's disease, and depression. CD4+ T cells are a highly heterogeneous and reprogrammable family, which includes various distinctive cell types such as Th17, Th1, and Treg cells. Interestingly Th17 and Treg cells share a related transcriptomic profile, where the TGFβ-SMADS pathway plays a fundamental role in regulating the differentiation of both of these cell types. However, Th17 could be highly pathogenic and was shown to promote inflammation in various neuropathological disorders. Conversely, Treg is anti-inflammatory and is known to inhibit Th17. It could be noticed that Th17 frequencies of infiltration of the blood-brain barrier in various neurological disorders are significantly upregulated. However, Treg infiltration numbers are significantly low. The reasons behind these contradicting observations are still unknown. In this perspective, we propose that the difference in the T-cell receptor repertoire diversity, diapedesis pathways, chemokine expression, and mechanical properties of these two cell types could be contributing to answering this intriguing question.

Anti-Psoriatic Effect of Rheum palmatum L. and Its Underlying Molecular Mechanisms

Psoriasis is a chronic, immune-mediated inflammatory skin disorder. Rheum palmatum L. is a common traditional medicinal herb with anti-inflammatory and immunomodulatory activities. This study aimed to investigate the anti-psoriatic effects of the ethanolic extract from R. palmatum L. (RPE) and its chemical constituents, as well as the mechanisms underlying their therapeutic significance. An imiquimod (IMQ)-induced psoriasis-like mouse model was used to examine the anti-psoriatic effect of RPE in vivo. Network pharmacological analysis was performed to investigate the potential targets and related pathways of the RPE components, including rhein, emodin, chrysophanol, aloe-emodin, and physcion. The anti-inflammatory effects and underlying mechanisms of these components were examined using in vitro models. Topical application of RPE alleviated psoriasis-like symptoms and reduced levels of inflammatory cytokines and proliferation markers in the skin. Network pharmacological analysis revealed that RPE components target 20 genes that are linked to psoriasis-related pathways, such as IL-17, MAPK, and TNF signaling pathways. Among the five components of RPE, rhein and emodin showed inhibitory effects on TNF-α and IL-17 production in EL-4 cells, attenuated the production of CXCL8, CXCL10, CCL20, and MMP9, and reduced proliferation in HaCaT cells. Chrysophanol, aloe-emodin, and physcion were less effective than rhein and emodin in suppressing inflammatory responses and keratinocyte proliferation. The effects of these compounds might occur through the inhibition of the ERK, STAT3, and NF-κB signaling pathways. This study suggested the anti-psoriatic effect of RPE, with rhein and emodin as the main contributors that regulate multiple signaling pathways.

Plasma Olink Proteomics Identifies CCL20 as a Novel Predictive and Diagnostic Inflammatory Marker for Preeclampsia

Inflammation is generally thought to be involved in the occurrence and development of preeclampsia (PE), but its specific effect on PE remains unclear. In the present study, the expression levels of 92 inflammation-related proteins were measured in the late pregnancy maternal plasma from patients with PE (n = 15) and normal pregnant controls (n = 15) using the Olink inflammation panel based on the highly sensitive and specific proximity extension assay technology. A total of 28 inflammation-related markers differed between the PE and control groups. Among them, fibroblast growth factor 21 (FGF-21) and cysteine-cysteine motif chemokine ligand 20 (CCL20) had the largest fold changes. We further validated the levels of CCL20 in the late (43 with PE and 44 controls) and early (37 with PE and 37 controls) pregnancy maternal plasma using enzyme-linked immunosorbent assay (ELISA). To the best of our knowledge, for the first time, CCL20 was found to be upregulated in the late and early pregnancy plasma of patients with PE and had an area under the curve (AUC) of 0.753 and 0.668, respectively. In conclusion, patients with PE had increased levels of most inflammatory markers, and CCL20 might be a novel potential predictive and diagnostic biomarker for PE.

Chronic Venous Disease during Pregnancy Causes a Systematic Increase in Maternal and Fetal Proinflammatory Markers

Chronic venous disease (CVD) is a common vascular disorder characterized by increased venous hypertension and insufficient venous return from the lower limbs. Pregnancy is a high-risk situation for developing CVD. Approximately a third of the women will develop this condition during pregnancy, and similarly to arterial hypertensive disorders, previous evidence has described a plethora of alterations in placental structure and function in women with pregnancy-induced CVD. It is widely known that arterial-induced placenta dysfunction is accompanied by an important immune system alteration along with increased inflammatory markers, which may provide detrimental consequences for the women and their offspring. However, to our knowledge, there are still no data collected regarding cytokine profiling in women with pregnancy-induced CVD. Thus, the aim of the present work was to examine cytokine signatures in the serum of pregnant women (PW) with CVD and their newborns (NB). This study was conducted through a multiplex technique in 62 PW with pregnancy-induced CVD in comparison to 52 PW without CVD (HC) as well as their NB. Our results show significant alterations in a broad spectrum of inflammatory cytokines (IL-6, IL-12, TNF-α, IL-10, IL-13, IL-2, IL-7, IFN-γ, IL-4, IL-5, IL-21, IL-23, GM-CSF, chemokines (fractalkine), MIP-3α, and MIP-1β). Overall, we demonstrate that pregnancy-induced CVD is associated with a proinflammatory environment, therefore highlighting the potentially alarming consequences of this condition for maternal and fetal wellbeing.

Sarcoid-like Granulomatosis Associated with Immune Checkpoint Inhibitors in Melanoma

We aimed to review the clinical and biological presentation of granulomatosis associated with immune-checkpoint inhibitors (ICI) in patients with melanoma and to explore its association with classical sarcoidosis as well as with cancer response to ICI. To this end, a retrospective study on 18 melanoma patients with histologically proven ICI-induced granulomatosis over a 12-year period in a single center, as well as on 67 similar cases reported in the literature, was conducted. Results indicate ICI-induced granulomatosis is an early side effect (median time to onset: 2 months). Its clinical presentation, with predominant (90%) thoracic involvement, histopathological appearance and supposed underlying biology (involving the mTOR pathway in immune cells, Th17 polarization and TReg dysfunction) are indistinguishable from those of sarcoidosis. Moreover, it appears to be associated with ICI benefit (>65% objective response rate). Evolution is generally favorable, and symptomatic steroid treatment and/or ICI discontinuation are rarely necessary. ICI-associated granulomatosis is critical to explore for several reasons. Practically, it is essential to differentiate it from cancer progression. Secondly, this “experimental” sarcoidosis brings new elements that may help to address sarcoidosis origin and pathophysiology. Its association with ICI efficacy must be confirmed on a larger scale but could have significant impacts on patient management and biomarker definition.

Plasminogen and plasmin can bind to human T cells and generate truncated CCL21 that increases dendritic cell chemotactic responses

Plasmin is a broad-spectrum protease and therefore needs to be tightly regulated. Active plasmin is formed from plasminogen, which is found in high concentrations in the blood and is converted by the plasminogen activators. In the circulation, high levels of α2-antiplasmin rapidly and efficiently inhibit plasmin activity. Certain myeloid immune cells have been shown to bind plasmin and plasminogen on their cell surface via proteins that bind to the plasmin(ogen) kringle domains. Our earlier work showed that T cells can activate plasmin, but that they do not themselves express plasminogen. Here, we demonstrate that T cells express several known plasminogen receptors, and that they bind plasminogen on their cell surface. We show T cell-bound plasminogen was converted to plasmin by plasminogen activators upon T cell activation. To examine functional consequences of plasmin generation by activated T cells, we investigated its effect on the chemokine, C-C Motif Chemokine Ligand 21 (CCL21). Video microscopy and western blotting confirmed that plasmin bound by human T cells cleaves CCL21 and increases the chemotactic response of monocyte-derived dendritic cells towards higher CCL21 concentrations along the concentration gradient by increasing their directional migration and track straightness. These results demonstrate how migrating T cells and potentially other activated immune cells may co-opt a powerful proteolytic system from the plasma towards immune processes in the peripheral tissues, where α2-antiplasmin is more likely to be absent. We propose that plasminogen bound to migrating immune cells may strongly modulate chemokine responses in peripheral tissues.

Proximal and Distal Regions of Pathogenic Th17 Related Chromatin Loci Are Sequentially Accessible During Pathogenicity of Th17

Pathogenic Th17, featured by their production of pro-inflammatory cytokines, are considered as a key player in most autoimmune diseases. The transcriptome of them is obviously distinct from that of conventional regulatory Th17. However, chromatin accessibility of the two Th17 groups have not been comprehensively compared yet. Here, we found that their chromatin-accessible regions(ChARs) significantly correlated with the expression of related genes, indicating that they might engage in the regulation of these genes. Indeed, pathogenic Th17 specific ChARs (patho-ChARs) exhibited a significant distribution preference in TSS-proximal region. We further filtered the patho-ChARs based on their conservation among mammalians or their concordance with the expression of their related genes. In either situation, the filtered patho-ChARs also showed a preference for TSS-proximal region. Enrichment of expression concordant patho-ChARs related genes suggested that they might involve in the pathogenicity of Th17. Thus, we also examined all ChARs of patho-ChARs related genes, and defined an opening ChAR set according to their changes in the Th17 to Th1 conversion. Interestingly, these opening ChARs displayed a sequential accessibility change from TSS-proximal region to TSS-distal region. Meanwhile, a group of patho-TFs (transcription factors) were identified based on the appearance of their binding motifs in the opening ChARs. Consistently, some of them also displayed a similar preference for binding the TSS-proximal region. Single-cell transcriptome analysis further confirmed that these patho-TFs were involved in the generation of pathogenic Th17. Therefore, our results shed light on a new regulatory mechanism underlying the generation of pathogenic Th17, which is worth to be considered for autoimmune disease therapy.

Multimodal profiling of lung granulomas in macaques reveals cellular correlates of tuberculosis control

Mycobacterium tuberculosis lung infection results in a complex multicellular structure: the granuloma. In some granulomas, immune activity promotes bacterial clearance, but in others, bacteria persist and grow. We identified correlates of bacterial control in cynomolgus macaque lung granulomas by co-registering longitudinal positron emission tomography and computed tomography imaging, single-cell RNA sequencing, and measures of bacterial clearance. Bacterial persistence occurred in granulomas enriched for mast, endothelial, fibroblast, and plasma cells, signaling amongst themselves via type 2 immunity and wound-healing pathways. Granulomas that drove bacterial control were characterized by cellular ecosystems enriched for type 1-type 17, stem-like, and cytotoxic T cells engaged in pro-inflammatory signaling networks involving diverse cell populations. Granulomas that arose later in infection displayed functional characteristics of restrictive granulomas and were more capable of killing Mtb. Our results define the complex multicellular ecosystems underlying (lack of) granuloma resolution and highlight host immune targets that can be leveraged to develop new vaccine and therapeutic strategies for TB.

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Timing of granuloma formation influences local microenvironment and bacterial burden

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Mast cells, type 2 immunity, and tissue remodeling underlie early, high-burden granulomas

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Type1-type17 and cytotoxic T cells associate with late-forming, low-burden granulomas

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Distinct interaction circuits across granuloma phenotypes nominate therapeutic targets

Coptisine Alleviates Imiquimod-Induced Psoriasis-like Skin Lesions and Anxiety-like Behavior in Mice

Psoriasis is a common inflammatory skin disorder, which can be associated with psychological disorders, such as anxiety and depression. This study investigated the efficacy and the mechanism of action of a natural compound coptisine using imiquimod (IMQ)-induced psoriasis mice. Coptisine reduced the severity of psoriasis-like skin lesions, decreased epidermal hyperplasia and the levels of inflammatory cytokines TNF-α, IL-17, and IL-22. Furthermore, coptisine improved IMQ-induced anxiety in mice by increasing the number of entries and time in open arms in the elevated plus maze (EPM) test. Coptisine also lowered the levels of inflammatory cytokines TNF-α and IL-1β in the prefrontal cortex of psoriasis mice. HaCaT keratinocytes and BV2 microglial cells were used to investigate the effects of coptisine in vitro. In M5-treated HaCaT cells, coptisine decreased the production of IL-6, MIP-3α/CCL20, IP-10/CXCL10, and ICAM-1 and suppressed the NF-κB signaling pathway. In LPS-stimulated BV2 cells, coptisine reduced the secretion of TNF-α and IL-1β. These findings suggest that coptisine might be a potential candidate for psoriasis treatment by improving both disease severity and psychological comorbidities.

Plasmin drives burn-induced systemic inflammatory response syndrome

Severe injuries, such as burns, provoke a systemic inflammatory response syndrome (SIRS) that imposes pathology on all organs. Simultaneously, severe injury also elicits activation of the fibrinolytic protease plasmin. While the principal adverse outcome of plasmin activation in severe injury is compromised hemostasis, plasmin also possesses proinflammatory properties. We hypothesized that, following a severe injury, early activation of plasmin drives SIRS. Plasmin activation was measured and related to injury severity, SIRS, coagulopathy, and outcomes prospectively in burn patients who are not at risk of hemorrhage. Patients exhibited early, significant activation of plasmin that correlated with burn severity, cytokines, coagulopathy, and death. Burn with a concomitant, remote muscle injury was employed in mice to determine the role of plasmin in the cytokine storm and inflammatory cascades in injured tissue distant from the burn injury. Genetic and pharmacologic inhibition of plasmin reduced the burn-induced cytokine storm and inflammatory signaling in injured tissue. These findings demonstrate (a) that severe injury-induced plasmin activation is a key pathologic component of the SIRS-driven cytokine storm and SIRS-activated inflammatory cascades in tissues distant from the inciting injury and (b) that targeted inhibition of plasmin activation may be effective for limiting both hemorrhage and tissue-damaging inflammation following injury.

Roles of the tissue-type plasminogen activator in immune response

The COVID-19 pandemic has once again brought to the forefront the existence of a tight link between the coagulation/fibrinolytic system and the immunologic processes. Tissue-type plasminogen activator (tPA) is a serine protease with a key role in fibrinolysis by converting plasminogen into plasmin that can finally degrade fibrin clots. tPA is released in the blood by endothelial cells and hepatocytes but is also produced by various types of immune cells including T cells and monocytes. Beyond its role on hemostasis, tPA is also a potent modulator of inflammation and is involved in the regulation of several inflammatory diseases. Here, after a brief description of tPA structure, we review its new functions in adaptive immunity focusing on T cells and antigen presenting cells. We intend to synthesize the recent knowledge on proteolysis- and receptor-mediated effects of tPA on immune response in physiological and pathological context.

Effects of Qing Chang Suppository Powder and its Ingredients on IL-17 Signal Pathway in HT-29 Cells and DSS-induced Mice

BACKGROUND

Qingchang Suppository, a formula used for more than 30 years in Longhua Hospital, has shown satisfactory clinical effects on Ulcerative Colitis (UC). However, its therapeutic mechanism has not been fully elucidated.

PURPOSE

The study aims to investigate the effects of Qingchang Suppository powder (QCSP) and its ingredients by regulating the IL-17A signaling pathway which plays an important role in the development of UC.

METHODS

HPLC was used to analyze the main ingredients (Gallic acid, Indigo, Indirubin) in QCSP. HT-29 cells were induced by rhIL-17A and TNF-α, and IL-17A related protein expressions were determined by western blot. BALB/C mice were induced by 4% Dextran Sodium sulfate (DSS). The effects of QCSP and its ingredients were evaluated by measuring weight loss, disease activity index (DAI), colon length, histological analysis. Western blot was used for analysis of IL-17A and MAPK related proteins p-ERK, p-JNK, p-P38. Quantitative reverse transcription polymerase chain reaction (q-PCR) was used to detect the expression of IL-17A, HSP90 and ACT1 in colon tissue. Cytokines such as IL-17A, IL-1β, IFN-γ and TNF-α were determinated by enzyme-linked immunosorbent assay (ELISA).

RESULTS

QCSP had good therapeutic effect on DSS-induced colitis in mice. QCSP significantly relieved weight loss, restored colon length, repaired colon lesions, reduced histological scores and DAI, decreased TNF-α, IL-1β, IL-17 and IFN-γ contents, significantly suppressed the gene expressions of IL-17A, ACT1 and HSP90, and up-regulated the expressions of tight junction proteins like ZO-1 and Occludin. IL-17A pathway related proteins such as IL-17A, IL-17RA, HSP90, MAPKs, P-iκbα and iNOS were significantly increased in vitro and in vivo.

CONCLUSIONS

This paper reveals that QCSP inhibited the IL-17A signaling pathway in HT-29 cells and DSS induced mice, presenting a new mechanism of QCS on treating UC.

Cerebrospinal Fluid IL-17A Could Predict Acute Disease Severity in Non-NMDA-Receptor Autoimmune Encephalitis

Introduction

Most of our knowledge into autoimmune encephalitis (AE) comes from N-Methyl-D-Aspartate Receptor (NMDAR) encephalitis. The concentrations of cytokines in cerebrospinal fluid (CSF) including IL-17A have been found to be increased and associated with poor outcome. However, data on the cytokine concentration in CSF and its correlation with outcome is lacking for other types of AE.

Objective

To report the concentrations of CSF sIL-2R, IL-6, IL-8, IL-10 and IL-17A and to correlate it with acute disease severity and the 1-year outcome in non-NMDAR AE.

Methods

We measured the CSF concentration of each cytokine in 20 AE patients, and compared IL-6 and IL-17A concentrations with 13 patients with CNS demyelinating diseases and 20 non-inflammatory controls. Patients were > 18yr and had at least 1-year clinical follow-up. Intracellular and NMDAR antibody (Ab) -mediated encephalitis were excluded. A mRS ≤ 2 was retained as a 1-year good outcome.

Results

The IL-17A concentration in CSF was higher in AE patients than in both control groups (p<0.01). No difference was observed in CSF concentration of IL-6 between groups. At disease onset, a high CSF IL-17A concentration correlated with a high modified Rankin Scale (p<0.05), a high Clinical Assessment Scale for Autoimmune Encephalitis score (p<0.001) and ICU admission (p<0.01). There was no correlation between the concentration of all CSF cytokines and the 1-year clinical outcome.

Conclusion

Our results show that CSF IL-17A could be interesting to assess initial severity in non-NMDAR AE. Thus, CSF IL-17A could be an interesting therapeutic target and be useful to assess early selective immunosuppressive therapy.

Natural Compound Mixture, Containing Emodin, Genipin, Chlorogenic Acid, Cimigenoside, and Ginsenoside Rb1, Ameliorates Psoriasis-Like Skin Lesions by Suppressing Inflammation and Proliferation in Keratinocytes

Herbal combinations of Rhei Radix et Rhizoma, Gardeniae Fructus, Cimicifugae Rhizoma, and Ginseng Radix have been used in traditional formulas to treat the symptoms of heat and dryness. This study investigated the therapeutic effects of a natural compound mixture (PSM) of these herbal combinations, containing emodin, genipin, chlorogenic acid, cimigenoside, and ginsenoside Rb1, for the treatment of psoriasis and its underlying molecular mechanisms. PSM was applied topically to the dorsal skin lesions of imiquimod- (IMQ-) induced C57BL/6 mice, and the expression of the proinflammatory mediators was investigated. The topical application of 1% PSM reduced psoriasis-like symptoms in IMQ-induced C57BL/6 mice significantly. PSM also attenuated the production of IFN-γ, IL-1β, and IL-6 in skin lesions. Histological analysis showed that PSM had antipsoriatic effects by reducing the lesional epidermal thickness. Either M5 (IL-1α, IL-17A, IL-22, oncostatin M, and TNF-α, 10 ng/ml each) or IL-22- (100 ng/ml) stimulated HaCaT cells were used to examine the efficacy and underlying mechanism of PSM. In M5-stimulated HaCaT cells, PSM inhibited the production of C-X-C motif chemokine ligand (CXCL) 10 and C-C motif chemokine ligand (CCL) 20 effectively. Moreover, compared to the use of a single compound, it had synergistic inhibitory effects in CXCL8 production. PSM suppressed the phosphorylation of ERK1/2, p38, and STAT3 signaling pathways in M5-stimulated HaCaT cells. Furthermore, PSM reduced the proliferation rate and K16 and K17 expressions in IL-22-stimulated HaCaT cells by inhibiting the Akt/mTOR signaling pathway. These results suggest that PSM may have a therapeutic potential in the treatment of psoriasis lesions.

Chemokines in allergic conjunctivitis

PURPOSE OF REVIEW

Chemokines are a large group of low molecular weight cytokines that attract and activate leukocytes throughout the body and therefore have a key role in the framework of late-phase allergic responses. The purpose of this article is to provide an overview of the main chemokines involved in allergic conjunctivitis, their primary functions and their physiological roles, and therapies targeted at chemokines and their receptors for ocular allergic diseases.

RECENT FINDINGS

In recent years, there have been considerable advances in the understanding of ocular pathophysiology of ocular surface inflammatory diseases including both allergic eye diseases and dry eye syndrome. Several therapies being developed for dry eye inflammation are recognized as possible therapies for ocular allergic diseases as there are often common chemokines involved in both disease spectra.

SUMMARY

Chemokines represent an integral part of the late-phase cascade of ocular allergic inflammation. A deep understanding of specific chemokines and their interactions will help in targeting therapies to effectively manage ocular clinical findings and symptoms of allergic eye disease.

CCL20 induced by visfatin in macrophages via the NF-κB and MKK3/6-p38 signaling pathways contributes to hepatic stellate cell activation

Chemokines interact with hepatic resident cells during inflammation and fibrosis. CC chemokine ligand (CCL) 20 has been reported to be important in inflammation and fibrosis in the liver. We hypothesized that visfatin, an adipocytokine, could play a role in hepatic fibrosis via CCL20. We investigated the effect of visfatin on CCL20 in THP-1 human promonocytic cells and examined the molecular mechanisms involved. Following treatment of THP-1 cells with visfatin, CCL20 expression and secretion were assessed. We assessed the intracellular signaling molecules IKK/NF-κB, JAK2/STAT3, MAPKs, and MKK3/6 by western blotting. We treated THP-1 cells with visfatin and signaling inhibitors, and examined CCL20 mRNA and protein levels. To investigate the effect of visfatin-induced CCL20 expression in hepatic stellate cells (HSCs), LX-2 cells were co-cultured with the culture supernatant of THP-1 cells with or without anti-CCL20 neutralizing antibodies, and fibrosis markers were examined by RT-PCR and immunoblotting. In THP-1 cells, visfatin increased the CCL20 mRNA and protein levels. visfatin increased the activities of the NF-κB, p38, and MLK3/6 signaling pathways but not those of the JAK2/STAT3 and ERK pathways. Visfatin treatment together with an NF-κB, p38, or MLK3 inhibitor reduced the mRNA and protein levels of CCL20. The visfatin-induced CCL20 increased the expression of fibrosis markers and CCR6 in HSCs. Following neutralization of CCL20, the levels of fibrosis markers and CCR6 were decreased. Visfatin increases the expression of CCL20 via the NF-κB and MKK3/6-p38 signaling pathways in macrophages, and visfatin-induced CCL20 expression promotes the fibrosis markers in HSCs.

Ets Family Transcription Factor Fli-1 Promotes Leukocyte Recruitment and Production of IL-17A in the MRL/Lpr Mouse Model of Lupus Nephritis

The transcription factor Friend leukemia integration 1 (Fli-1) regulates the expression of numerous cytokines and chemokines and alters the progression of lupus nephritis in humans and in the MRL/MpJ-Fas^lpr (MRL/lpr) mouse model. Th17-mediated immune responses are notably important as they promote ongoing inflammation. The purpose of this study is to determine the impact of Fli-1 on expression of interleukin-17A (IL-17A) and the infiltration of immune cells into the kidney. IL-17A concentrations were measured by ELISA in sera collected from MRL/lpr Fli-1-heterozygotes (Fli-1^+/−) and MRL/lpr Fli-1^+/+ control littermates. Expression of IL-17A and related proinflammatory mediators was measured by real-time polymerase chain reaction (RT-PCR). Immunofluorescence staining was performed on renal tissue from MRL/lpr Fli-1^+/− and control littermates using anti-CD3, anti-CD4, and anti-IL-17A antibodies to detect Th17 cells and anti-CCL20 and anti-CD11b antibodies to identify CCL20⁺ monocytes. The expression of IL-17A in renal tissue was significantly reduced; this was accompanied by decreases in expression of IL-6, signal transducer and activator of transcription 3 (STAT3), and IL-1β. Likewise, we detected fewer CD3⁺IL-17⁺ and CD4⁺IL-17⁺ cells in renal tissue of MLR/lpr Fli-1^+/− mice and significantly fewer CCL20⁺CD11b⁺ monocytes. In conclusion, partial deletion of Fli-1 has a profound impact on IL-17A expression and on renal histopathology in the MRL/lpr mouse.

PPARγ Deficiency in Carbon Nanotube-elicited Granulomatous Inflammation Promotes a Th17 Response to a Microbial Antigen

BACKGROUND

The pathological consequences of interaction between environmental carbon pollutants and microbial antigens have not been fully explored. We developed a murine model of multi-wall carbon nanotube (MWCNT)-elicited granulomatous disease which bears a striking resemblance to sarcoidosis, a human granulomatous disease. Because of reports describing lymphocyte reactivity to mycobacterial antigens in sarcoidosis patients, we hypothesized that addition of mycobacterial antigen (ESAT-6) to MWCNT might elicit activation in T cells.

METHODS

Macrophage-specific peroxisome-proliferator-activated receptor gamma (PPARγ) knock out (KO) mice were studied along with wild-type mice because our previous report indicated PPARγ deficiency in sarcoidosis alveolar macrophages. MWCNT+ESAT-6 were instilled into mice. Controls received vehicle (surfactant-PBS) or ESAT-6 and were evaluated 60 days post-instillation. As noted in our recent publication, lung tissues from PPARγ KO mice instilled with MWCNT+ESAT-6 yielded more intensive pathophysiology, with elevated fibrosis.

RESULTS

Inspection of mediastinal lymph nodes (MLN) revealed no granulomas but deposition of MWCNT. MLN cell counts were higher in PPARγ KO than in wild-type instilled with MWCNT+ESAT-6. Moreover, the CD4:CD8 T cell ratio, a major clinical metric for human disease, was increased in PPARγ KO mice. Bronchoalveolar lavage (BAL) cells from PPARγ KO mice instilled with MWCNT+ESAT-6 displayed increased Th17 cell markers (RORγt, IL-17A, CCR6) which associate with elevated fibrosis.

CONCLUSION

These findings suggest that PPARγ deficiency in macrophages may promote ESAT-6-associated T cell activation in the lung, and that the MWCNT+ESAT-6 model may offer new insights into pathways of lymphocyte-mediated sarcoidosis histopathology.

Atherosclerosis: orchestrating cells and biomolecules involved in its activation and inhibition

The term atherosclerosis refers to the condition of deposition of lipids and other substances in and on the artery walls, called as plaque that restricts the normal blood flow. The plaque may be stable or unstable in nature. Unstable plaque can burst and trigger clot formation adding further adversities. The process of plaque formation involves various stages including fatty streak, intermediate or fibro-fatty lesion and advanced lesion. The cells participating in the formation of atherosclerotic plaque include endothelial cells, vascular smooth muscle cells (VSMC), monocytes, monocytes derived macrophages, macrophages and dendritic cells and regulatory T cells (T_REG). The role of a variety of cytokines and chemokines have been studied which either help in progression of atherosclerotic plaque or vice versa. The cytokines involved in atherosclerotic plaque formation include IL-1, IL-2, IL-3, IL-4, IL-5, IL-6, IL-9, IL-10, IL-12, IL-13, IL-15, IL-17, IL-18, IL-20, IL-25, IL-27, IL-33, IL-37, TNF-α, TGF-β and IFN-γ; whereas amongst the chemokines (family of small cytokines) are CCL2, CCL3, CXCL4, CCL5, CXCL1, CX3CL1, CCL17, CXCL8, CXCL10, CCL20, CCL19 and CCL21 and macrophage migration-inhibitory factor. These are involved in the atherosclerosis advancements, whereas the chemokine CXCL12 is play atheroprotective roles. Apart this, contradictory functions have been documented for few other chemokines such as CXCL16. Since the cytokines and chemokines are amongst the key molecules involved in orchestrating the atherosclerosis advancements, targeting them might be an effective strategy to encumber the atherosclerotic progression. Blockage of cytokines and chemokines via the means of broad-spectrum inhibitors, neutralizing antibodies, usage of decoy receptors or RNA interference have been proved to be useful intervention against atherosclerosis.

Th17 cells were recruited and accumulated in the cerebrospinal fluid and correlated with the poor prognosis of anti-NMDAR encephalitis

Anti-N-methyl-D-aspartate-receptor (NMDAR) encephalitis is an autoimmune disorder characterized by memory deficits, psychiatric symptoms, and autonomic instability. The lack of suitable biomarkers targeting anti-NMDAR encephalitis makes the immunotherapy and prognosis challenging. In this study, we found that the Th17 cells were significantly accumulated in the cerebrospinal fluid (CSF) of anti-NMDAR encephalitis patients than that of control individuals. The concentration of the cytokines and chemokines including interleukin (IL)-1β, IL-17, IL-6, and CXCL-13 were significantly increased in the CSF of anti-NMDAR encephalitis patients. IL-6 and IL-17 were found to promote the differentiation of CD4+ T cells into Th17 lineage. The chemotaxis assay showed that CCL20 and CCL22 play essential roles in the migration of Th17 cells. Notably, the correlation between the expression of IL-17 and the outcome of anti-NMDAR encephalitis patients was analyzed. The data showed that high level of IL-17 was significantly correlated with the limited response to the treatment and relapse of anti-NMDAR encephalitis patients. Our results suggested the potential important involvement of IL-17 in anti-NMDAR encephalitis.

C-C Motif Ligand 20 (CCL20) and C-C Motif Chemokine Receptor 6 (CCR6) in Human Peripheral Blood Mononuclear Cells: Dysregulated in Ulcerative Colitis and a Potential Role for CCL20 in IL-1β Release

The chemokine C-C motif ligand 20 (CCL20) is increased in the colonic mucosa during active inflammatory bowel disease (IBD) and can be found both in the epithelium and immune cells in the lamina propria. The present study investigated CCL20 and C-C motif Chemokine Receptor 6 (CCR6) in peripheral blood mononuclear cells (PBMCs) (n = 40) from IBD patients and healthy controls, to identify inductors of CCL20 release encountered in a local proinflammatory environment. CCL20 release from PBMCs was increased when activating TLR2/1 or NOD2, suggesting that CCL20 is part of a first line response to danger-associated molecular patterns also in immune cells. Overall, ulcerative colitis (UC) had a significantly stronger CCL20 release than Crohn’s disease (CD) (+242%, p < 0.01), indicating that the CCL20-CCR6 axis may be more involved in UC. The CCL20 receptor CCR6 is essential for the chemotactic function of CCL20. UC with active inflammation had significantly decreased CCR6 expression and a reduction in CCR6⁺ cells in circulation, indicating chemoattraction of CCR6⁺ cells from circulation towards peripheral tissues. We further examined CCL20 induced release of cytokines from PBMCs. Stimulation with CCL20 combined with TNF increased IL-1β release from PBMCs. By attracting additional immune cells, as well as inducing proinflammatory IL-1β release from immune cells, CCL20 may protract the inflammatory response in ulcerative colitis.

Leprosy Reactions Show Increased Th17 Cell Activity and Reduced FOXP3+ Tregs with Concomitant Decrease in TGF-β and Increase in IL-6

BACKGROUND

50% of leprosy patients suffer from episodes of Type 1/ reversal reactions (RR) and Type 2/ Erythema Nodosum Leprosum (ENL) reactions which lead to morbidity and nerve damage. CD4+ subsets of Th17 cells and CD25+FOXP3+ regulatory T cells (Tregs) have been shown to play a major role in disease associated immunopathology and in stable leprosy as reported by us and others. The aim of our study was to analyze their role in leprosy reactions.

METHODOLOGY AND PRINCIPLE FINDINGS

Quantitative reverse transcribed PCR (qPCR), flowcytometry and ELISA were used to respectively investigate gene expression, cell phenotypes and supernatant levels of cytokines in antigen stimulated PBMC cultures in patients with stable disease and those undergoing leprosy reactions. Both types of reactions are associated with significant increase of Th17 cells and associated cytokines IL-17A, IL-17F, IL-21, IL-23 and chemokines CCL20, CCL22 as compared to matching stable forms of leprosy. Concurrently patients in reactions show reduction in FOXP3+ Treg cells as well as reduction in TGF-β and increase in IL-6. Moreover, expression of many T cell markers, cytokines, chemokines and signaling factors were observed to be increased in RR as compared to ENL reaction patients.

CONCLUSIONS

Patients with leprosy reactions show an imbalance in Th17 and Treg populations. The reduction in Treg suppressor activity is associated withhigherTh17cell activity. The combined effect of reduced TGF-β and enhanced IL-6, IL-21 cytokines influence the balance between Th17 or Treg cells in leprosy reactions as reported in the murine models and autoimmune diseases. The increase in Th17 cell associated cytokines may contribute to lesional inflammation.

The Interplay Between Monocytes/Macrophages and CD4(+) T Cell Subsets in Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a chronic inflammatory disease characterized by inflammation of the synovial lining (synovitis). The inflammation in the RA joint is associated with and driven by immune cell infiltration, synovial hyperproliferation, and excessive production of proinflammatory mediators, such as tumor necrosis factor α (TNFα), interferon γ (IFNγ), interleukin (IL)-1β, IL-6, and IL-17, eventually resulting in damage to the cartilage and underlying bone. The RA joint harbors a wide range of immune cell types, including monocytes, macrophages, and CD4(+) T cells (both proinflammatory and regulatory). The interplay between CD14(+) myeloid cells and CD4(+) T cells can significantly influence CD4(+) T cell function, and conversely, effector vs. regulatory CD4(+) T cell subsets can exert profound effects on monocyte/macrophage function. In this review, we will discuss how the interplay between CD4(+) T cells and monocytes/macrophages may contribute to the immunopathology of RA.

Aryl Hydrocarbon Receptor Activation Synergistically Induces Lipopolysaccharide-Mediated Expression of Proinflammatory Chemokine (c-c motif) Ligand 20

The Ah receptor (AHR) is directly involved in the regulation of both innate and adaptive immunity. However, these activities are poorly understood at the level of gene regulation. The chemokine (c-c motif) ligand 20 (CCL20) plays a nonredundant role in the chemoattraction of C-C motif receptor 6 expressing cells (eg, T cells and others). A survey of promoter regions of chemokine genes revealed that there are several putative dioxin responsive elements in the mouse Ccl20 promoter. The addition of an AHR agonist along with lipopolysaccharide (LPS) to cultured primary peritoneal macrophages results in synergistic induction of both Ccl20 mRNA and protein, compared with each compound alone. Through the use of macrophage cultures derived from Ahr(-) (/) (-) and Ahr(nls/nls) mice, it was established that expression of the AHR and its ability to translocate into the nucleus are necessary for AHR ligand-mediated synergistic induction of Ccl20. Gel shift analysis determined that a potent tandem AHR binding site ~3.1 kb upstream from the transcriptional start site can efficiently bind the AHR/ARNT (aryl hydrocarbon receptor/AHR nuclear translocator) heterodimer upon activation with a number of AHR agonists. Furthermore, studies reveal that LPS increases AHR levels on the Ccl20 promoter while decreasing HDAC1 occupancy. The level of Ccl20 constitutive expression in the colon is greatly attenuated in Ahr(-) (/) (-) mice. These studies suggest that the presence of AHR ligands during localized inflammation may augment chemokine expression, thus participating in the overall response to pathogens.

Proinflammatory effects and molecular mechanisms of interleukin-17 in intestinal epithelial cell line HT-29

AIM: To evaluate the proinflammatory effects and molecular mechanisms of interleukin (IL)-17 in intestinal epithelial cell line HT-29.

METHODS: HT-29 cells were cultured with IL-17, tumor necrosis factor (TNF)-α, or the combination of both IL-17 and TNF-α. Real-time PCR and Western blot were used to measure the gene expression levels of neutrophil chemokines CXCL1, CXCL2, CXCL5, CXCL6, IL-8 and TH-17 cell chemokine CCL20, the phosphorylation levels of p38 and TNF-α, and the expression level of IL-8, after using the p38 inhibitor in HT-29 cells. The stable Act1 knockdown HT-29 cell line was established to further test the phosphorylation changes of p38, after using IL-17 and TNF-α.

RESULTS: After HT-29 cells were cultured with IL-17 and TNF-α, the expression levels of neutrophil chemokines (CXCL1, CXCL2, CXCL5, CXCL6, IL-8) and Th17 chemokine (CCL20) significantly improved (24.96 ± 2.53, 28.47 ± 2.87, 38.08 ± 2.72, 33.47 ± 2.41, 31.7 ± 2.38, 44.37 ± 2.73, respectively), and the differences were all statistically significant (P < 0.01). Western blot results showed that IL-17 obviously enhanced the phosphorylation level of p38, which was induced by TNF-α. Compared with the control group, the expression level of IL-8 significantly declined (9.47 ± 1.36 vs 3.06 ± 0.67, P < 0.01) when TH-29 cells were cultured with IL-17 and TNF-α. p38 inhibition assay showed that the p38 pathway played an essential role in the inflammatory response induced by IL-17. p38 phosphorylation levels could not be changed after using IL-17 and TNF-α in the stable Act1 knockdown HT-29 cell line.

CONCLUSION: IL-17 significantly promoted the gene expression levels of TNF-α-induced neutrophil chemokines and Th17 cell chemokine. It is obvious that IL-17 and TNF-α have synergistic effects on p38.

Recent advances on plasmin inhibitors for the treatment of fibrinolysis-related disorders

Growing evidence suggests that plasmin is involved in a number of physiological processes in addition to its key role in fibrin cleavage. Plasmin inhibition is critical in preventing adverse consequences arising from plasmin overactivity, e.g., blood loss that may follow cardiac surgery. Aprotinin was widely used as an antifibrinolytic drug before its discontinuation in 2008. Tranexamic acid and ε-aminocaproic acid, two small molecule plasmin inhibitors, are currently used in the clinic. Several molecules have been designed utilizing covalent, but reversible, chemistry relying on reactive cyclohexanones, nitrile warheads, and reactive aldehyde peptidomimetics. Other major classes of plasmin inhibitors include the cyclic peptidomimetics and polypeptides of the Kunitz and Kazal-type. Allosteric inhibitors of plasmin have also been designed including small molecule lysine analogs that bind to plasmin's kringle domain(s) and sulfated glycosaminoglycan mimetics that bind to plasmin's catalytic domain. Plasmin inhibitors have also been explored for resolving other disease states including cell metastasis, cell proliferation, angiogenesis, and embryo implantation. This review highlights functional and structural aspects of plasmin inhibitors with the goal of advancing their design.

Bacterial siderophores that evade or overwhelm lipocalin 2 induce hypoxia inducible factor 1α and proinflammatory cytokine secretion in cultured respiratory epithelial cells

Iron is essential for many cellular processes and is required by bacteria for replication. To acquire iron from the host, pathogenic Gram-negative bacteria secrete siderophores, including enterobactin (Ent). However, Ent is bound by the host protein lipocalin 2 (Lcn2), preventing bacterial reuptake of aferric or ferric Ent. Furthermore, the combination of Ent and Lcn2 (Ent+Lcn2) leads to enhanced secretion of interleukin-8 (IL-8) compared to that induced by either stimulus alone. Modified or structurally distinct siderophores, including yersiniabactin (Ybt) and glycosylated Ent (GlyEnt, or salmochelin), deliver iron to bacteria despite the presence of Lcn2. We hypothesized that the robust immune response to Ent and Lcn2 requires iron chelation rather than the Ent+Lcn2 complex itself and also can be stimulated by Lcn2-evasive siderophores. To test this hypothesis, cultured respiratory epithelial cells were stimulated with combinations of purified siderophores and Lcn2 and analyzed by gene expression microarrays, quantitative PCR, and cytokine immunoassays. Ent caused HIF-1α protein stabilization, induced the expression of genes regulated by hypoxia-inducible factor 1α (HIF-1α), and repressed genes involved in cell cycle and DNA replication, whereas Lcn2 induced expression of proinflammatory cytokines. Iron chelation by excess Ent or Ybt significantly increased Lcn2-induced secretion of IL-8, IL-6, and CCL20. Stabilization of HIF-1α was sufficient to enhance Lcn2-induced IL-6 secretion. These data indicate that respiratory epithelial cells can respond to bacterial siderophores that evade or overwhelm Lcn2 binding by increasing proinflammatory cytokine production.