High Levels Of Inflammatory Cytokines Research Articles

Slit2 Modulates the Inflammatory Phenotype of Orbit-Infiltrating Fibrocytes in Graves' Disease.

Human CD34+ fibrocytes, circulating monocyte lineage progenitor cells, have recently been implicated in thyroid-associated ophthalmopathy (TAO), the ocular manifestation of Graves' disease (GD). Fibrocytes express constitutive MHC class II (MHC-2) and, surprisingly, thyroglobulin (Tg) and functional thyrotropin (TSH) receptor (TSHR). Underlying expression of these thyroid proteins is the autoimmune regulator protein (AIRE). Fibrocytes respond robustly to TSH and thyroid-stimulating Igs by generating extremely high levels of inflammatory cytokines, such as IL-6. In TAO, they appear to infiltrate the orbit, where they transition to CD34+ orbital fibroblasts (OF). There, they coexist with CD34- OF as a mixed fibroblast population (GD-OF). In contrast to fibrocytes, GD-OF express vanishingly low levels of MHC-2, Tg, TSHR, and AIRE. Further, the amplitude of IL-6 induction by TSH in GD-OF is substantially lower. The molecular basis for this divergence between fibrocytes and CD34+ OF remains uncertain. In this article, we report that Slit2, an axon guidance glycoprotein, is constitutively expressed by the CD34- OF subset of GD-OF. Culture conditioned medium (CM) generated by incubating with GD-OF and CD34- OF substantially reduces levels of MHC-2, Tg, TSHR, and AIRE in fibrocytes. Expression can be restored by specifically depleting CM of Slit2. The effects of CD34- OF CM are mimicked by recombinant human Slit2. TSH induces Slit2 levels in GD-OF by enhancing both Slit2 gene transcription and mRNA stability. These findings suggest that Slit2 represents a TSH-inducible factor within the TAO orbit that can modulate the inflammatory phenotype of CD34+ OF and therefore may determine the activity and severity of the disease.

Intradermal active full-length DNA Aβ42 immunization via electroporation leads to high anti-Aβ antibody levels in wild-type mice

Aβ immunotherapies with anti-Aβ antibody responses have high potential as possible prevention treatment for Alzheimer's disease. We have previously shown that active DNA Aβ1–42 immunization via gene gun delivery led to a non-inflammatory immune response resulting in decreased Aβ levels in brains of an immunized AD mouse model. To make DNA vaccination more applicable for clinical use, we used here intradermal electroporation. With fine tuning of the electropulse parameters, high antibody levels and low levels of inflammatory cytokines in the cellular immunoassays were observed. Full-length DNA Aβ1–42 immunization delivered via electroporation has potential to be used in the clinical setting.

Epigallocatechin gallate attenuates mitochondrial DNA-induced inflammatory damage in the development of ventilator-induced lung injury

ObjectiveWe aim to investigate the role of mitochondrial DNA (mtDNA), a novel endogenous pro-inflammatory cytokine, in the development of ventilator-induced lung injury (VILI). Moreover, the protective effect of epigallocatechin gallate (EGCG) on VILI through inhibiting local mtDNA release was examined. MethodsFrom March 2015 to March 2016, bronchoalveolar lavage fluid (BALF) from 36 patients with VILI and well-matched 36 patients without VILI after major surgery were consecutively collected. The expression levels of mtDNA and inflammatory cytokines in BALF were tested. SD rats were divided into five groups: control, low tidal volume (7 ml/kg) group, high tidal volume (HTV, 40 ml/kg) group, HTV+low dose EGCG and HTV+high dose EGCG groups. BALF were collected to examine the expression levels of mtDNA and several inflammatory cytokines and the lung tissue was harvested for pathological examinations. In addition, cyclic stretch cell culture was used and culture media was collected to analyze expressions of inflammatory cytokines. Administration of mtDNA in a rat model and in vitro cell culturing were used to confirm its pro-inflammatory properties in the development of inflammatory lung injury. ResultsA Significant elevation of mtDNA was detected in BALF from patients with VILI (581 ± 193 vs. 311 ± 137, p < 0.05) and also in rats ventilated with HTV. EGCG could significantly inhibit HTV-induced local mtDNA release and attenuate the level of inflammatory lung injuries (reduced infiltration of local inflammatory cells, lower lung wet/dry ratio and expression levels of inflammatory cytokines). The beneficial effects of EGCG on preventing inflammatory lung injuries were in a concentration-dependent manner. Meanwhile, higher expression levels of mtDNA and inflammatory cytokines were observed in the media of cyclic stretched cell culture compared to those in the control group (p < 0.05). Furthermore, intra-tracheal administration of mtDNA in rats could lead to a marked increase of local inflammatory cytokines and subsequent inflammatory lung injuries (p < 0.05). And by adding mtDNA into the cell culture, higher level of inflammatory cytokines in the media was detected (p < 0.05). EGCG also showed preventive effects on inflammatory responses on a concentration-dependent manner (p < 0.05). ConclusionThe increased expression level of mtDNA and subsequent inflammatory cytokines overproduction may play an important role in the development of VILI. EGCG may be a potential novel therapeutic candidate for protection against VILI by inhibiting the local release of mtDNA.

Evidence of the impact of systemic inflammation on neuroinflammation from a non-bacterial endotoxin animal model

BackgroundSystemic inflammation induces neuroinflammation and cellular changes such as tau phosphorylation to impair cognitive function, including learning and memory. This study uses a single model, laparotomy without any pathogen, to characterize these changes and their responses to anti-inflammatory treatment in the intermediate term.MethodsIn a two-part experiment, wild-type C57BL/6N mice (male, 3 month old, 25 ± 2 g) were subjected to sevoflurane anesthesia alone or to a laparotomy. Cognitive performance, systemic and neuroinflammatory responses, and tau phosphorylation were evaluated on postoperative days (POD) 1, 3, and 14. The effect of perioperative ibuprofen intervention (60 mg/kg) on these changes was then assessed.ResultsMice in the laparotomy group displayed memory impairment up to POD 14 with initial high levels of inflammatory cytokines in the liver, frontal cortex (IL-1β, IL-6, and TNF-α), and hippocampus (IL-1β and IL-8). On POD 14, although most circulating and resident cytokine levels returned to normal, a significant number of microglia and astrocytes remained activated in the frontal cortex and microglia in the hippocampus, as well as abnormal tau phosphorylation in these two brain regions. Perioperative ibuprofen improved cognitive performance, attenuated systemic inflammation and glial activation, and suppressed the abnormal tau phosphorylation both in the frontal cortex and hippocampus.ConclusionsOur results suggest that (1) cognitive dysfunction is associated with an unbalanced pro-inflammatory and anti-inflammatory response, tauopathy, and gliosis; (2) cognitive dysfunction, gliosis, and tauopathy following laparotomy can persist well beyond the immediate postoperative period; and (3) anti-inflammatory drugs can act rapidly to attenuate inflammatory responses in the brain and negatively modulate neuropathological changes to improve cognition. These findings may have implications for the duration of therapeutic strategies aimed at curtaining cognitive dysfunction following surgery.

253 - Comparison of human adipose stromal vascular fraction and adipose-derived mesenchymal stem cells for the attenuation of acute renal ischemia/reperfusion injury

Stem cells therapy has been suggested as a promising option for the treatment of acute kidney injury (AKI). This study was performed to compare the abilities of xenogenic transplantation of human adipose stromal vascular fraction (SVF) and adipose-derived mesenchymal stem cells (AdMSCs) to facilitate the recovery of renal function and structure in a rat model of ischemia/reperfusion (IR) induced AKI. SVF or AdMSCs were transplanted to the injured kidney through intra-parenchymal injection. Significantly improved renal function and reduced tubular injury were observed in SVF and AdMSCs groups. Administration of SVF or AdMSCs contributed to significantly improved cell proliferation and markedly reduced cell apoptosis in parallel with reduced microvascular rarefaction in injured kidney. IR injury resulted in higher levels of inflammatory cytokines, whereas xenogenic transplantation of SVF or AdMSCs reduced but not induced inflammatory cytokines expression. Additionally, in vitro study showed that administration of SVF or AdMSCs could also significantly promote the proliferation and survival of renal tubular epithelial cells underwent hypoxia/reoxygenation injury through secreting various growth factors. However, cell proliferation was significantly promoted in SVF group than in AdMSCs group. In conclusion, our study demonstrated that administration of SVF or AdMSCs was equally effective in attenuating acute renal IR injury.

Punicalagin induces senescent growth arrest in human papillary thyroid carcinoma BCPAP cells via NF-κB signaling pathway

Papillary thyroid carcinoma (PTC) is the most common endocrine carcinoma. Our previous study revealed that punicalagin (PUN), an active component from pomegranate, triggered autophagic cell death and DNA damage response (DDR) in papillary thyroid carcinoma BCPAP cells. But the detailed anti-cancer mechanisms of punicalagin against PTC still remained to be further explored. DDR activation is a proven cause of cellular senescence, which mediates anti-tumor processes under certain circumstances. In this study, we reported that punicalagin treatment generated a senescent phenotype of BCPAP cells characterized as altered morphology, increased cell granularity and senescence-associated β-galactosidase (SA-β-Gal) staining. Senescence induced by punicalagin treatment was further confirmed by cell cycle arrest and upregulation of cyclin-dependent kinase inhibitor p21. Meanwhile, the senescence-associated secretory phenotype (SASP) included high levels of inflammatory cytokines, principally IL-6 and IL-1β. Furthermore, punicalagin exposure caused the phosphorylation and subsequent degradation of IκBα as well as the nuclear translocation of p65, suggesting the activation of NF-κB signaling pathway. Inhibition of NF-κB by pyrrolidine dithiocarbamate (PDTC), a selective inhibitor of NF-κB, partially reversed the cellular senescent phenotype induced by punicalagin in BCPAP cells as evidenced by the decreased fraction of SA-β-Gal staining positive cells and blockage of SASP generation. These results collectively showed that punicalagin treatment induced senescent growth arrest and SASP via triggering NF-κB activation. These observations elucidated novel anti-cancer mechanisms of punicalagin and might provide new potential prospects for PTC therapy.

Cytokine Responses in Severe Traumatic Brain Injury: Where There Is Smoke, Is There Fire?

This scoping review will discuss the basic functions and prognostic significance of the commonly researched cytokines implicated in severe traumatic brain injury (sTBI), including tumour necrosis factor-α (TNF-α), interleukin-1β (IL-1β), IL-6, tissue inhibitor of matrix metalloproteinases-1 (TIMP-1), transforming growth factor-β (TGF-β), substance P, and soluble CD40 ligand (sCD40L). A scoping review was undertaken with an electronic search for articles from the Ovid MEDLINE, PUBMED and EMBASE databases from 1995 to 2017. Inclusion criteria were original research articles, and reviews including both animal models and human clinical studies of acute (< 3months) sTBI. Selected articles included both isolated sTBI and sTBI with systemic injury. After applying the inclusion criteria and removing duplicates, 141 full-text articles, 126 original research articles and 15 review articles, were evaluated in compiling this review paper. A single reviewer, CC, completed the review in two phases. During the first phase, titles and abstracts of selected articles were reviewed for inclusion. A second evaluation was then conducted on the full text of all selected articles to ensure relevancy. From our current understanding of the literature, it is unlikely a single biomarker will be sufficient in accurately prognosticating patients with sTBI. Intuitively, a more severe injury will demonstrate higher levels of inflammatory cytokines which may correlate as a marker of severe injury. This does not mean, necessarily, these cytokines have a direct and causal role in the poor outcome of the patient. Further research is required to better delineate the complex systemic inflammatory and CNS interactions that occur during sTBI before they can be applied as a reliable prognostic tool.

Cancer patients in operative intensive care medicine

ZusammenfassungDie Prävalenz onkologischer Erkrankungen ist in den vergangenen Jahrzehnten stetig angestiegen. Durch neue Therapieoptionen können immer mehr Patienten mit einem kurativen Therapieansatz behandelt werden. Diese individualisierten und teilweise sehr aggressiven Therapien können jedoch auch zu schweren Nebenwirkungen führen. Diese sollten als wichtige Differenzialdiagnosen zu anderen vitalbedrohlichen Krankheitsbildern auch dem im OP und als Intensivmediziner tätigen Anästhesisten bekannt sein. Krebspatienten werden häufig auf operativen Intensivstationen aufgenommen, um Komplikationen der malignen Grunderkrankung oder auch Nebenwirkungen einer operativen oder konservativen Therapie zu behandeln. Aktuelle Untersuchungen zeigen, dass die maligne Grunderkrankung entgegen bisheriger Annahme keinen wesentlichen Einfluss auf das Intensivüberleben hat. Bei der Aufnahme eines onkologischen Patienten sollte daher die akut vorliegende Organdysfunktion zunächst im Vordergrund stehen. Bei der Therapiezielplanung gilt es, nicht zu übersehen, wann ein kuratives in ein palliatives Konzept übergehen muss. Hierfür müssen neue Aufnahmestrategien und -kriterien entwickelt und evaluiert werden. In diesem Übersichtsartikel werden Diagnosen und Therapien häufiger intensivmedizinischer Krankheitsbilder von onkologischen Patienten sowie Nebenwirkungen moderner onkologischer Therapien dargelegt und Aufnahmestrategien für Patienten mit malignen Erkrankungen vorgestellt.

Thrombosis in Philadelphia negative classical myeloproliferative neoplasms: a narrative review on epidemiology, risk assessment, and pathophysiologic mechanisms.

Thrombosis is common in cancer patients and is associated with increased morbidity and mortality. Myeloproliferative neoplasms (MPN) are common malignancies in elderly individuals and are known for a high incidence of thrombotic complications. Different risk factors have been identified in studies, and risk models have been developed to identify patients with MPN at higher risk for thrombosis. Several pathophysiological mechanisms help explain the increased likelihood of thrombosis in these patients. Factors, such as leukocyte and platelet activation leading to the formation of leukocyte-platelet aggregates, activation of the coagulation cascade by microparticles, high levels of inflammatory cytokines, and endothelial dysfunction have a crucial role in thrombosis in MPN patients. Recent studies have demonstrated a significant association between the allele burden of specific genetic mutations (mainly JAK2V617F) associated with MPN and the incidence of thrombotic events, thus suggesting a possible role for these mutations in thrombogenesis.

Emerging roles of extracellular vesicles in cellular senescence and aging.

SummaryCellular senescence is a cellular program that prevents the proliferation of cells at risk of neoplastic transformation. On the other hand, age‐related accumulation of senescent cells promotes aging at least partially due to the senescence‐associated secretory phenotype, whereby cells secrete high levels of inflammatory cytokines, chemokines, and matrix metalloproteinases. Emerging evidence, however, indicates that extracellular vesicles (EVs) are important mediators of the effects of senescent cells on their microenvironment. Senescent cells secrete more EphA2 and DNA via EVs, which can promote cancer cell proliferation and inflammation, respectively. Extracellular vesicles secreted from DNA‐damaged cells can also affect telomere regulation. Furthermore, it has now become clear that EVs actually play important roles in many aspects of aging. This review is intended to summarize these recent progresses, with emphasis on relationships between cellular senescence and EVs.

Cancer patients in operative intensive care medicine

ZusammenfassungDie Prävalenz onkologischer Erkrankungen ist in den vergangenen Jahrzehnten stetig angestiegen. Durch neue Therapieoptionen können immer mehr Patienten mit einem kurativen Therapieansatz behandelt werden. Diese individualisierten und teilweise sehr aggressiven Therapien können jedoch auch zu schweren Nebenwirkungen führen. Diese sollten als wichtige Differenzialdiagnosen zu anderen vitalbedrohlichen Krankheitsbildern auch dem im OP und als Intensivmediziner tätigen Anästhesisten bekannt sein. Krebspatienten werden häufig auf operativen Intensivstationen aufgenommen, um Komplikationen der malignen Grunderkrankung oder auch Nebenwirkungen einer operativen oder konservativen Therapie zu behandeln. Aktuelle Untersuchungen zeigen, dass die maligne Grunderkrankung entgegen bisheriger Annahme keinen wesentlichen Einfluss auf das Intensivüberleben hat. Bei der Aufnahme eines onkologischen Patienten sollte daher die akut vorliegende Organdysfunktion zunächst im Vordergrund stehen. Bei der Therapiezielplanung gilt es, nicht zu übersehen, wann ein kuratives in ein palliatives Konzept übergehen muss. Hierfür müssen neue Aufnahmestrategien und -kriterien entwickelt und evaluiert werden. In diesem Übersichtsartikel werden Diagnosen und Therapien häufiger intensivmedizinischer Krankheitsbilder von onkologischen Patienten sowie Nebenwirkungen moderner onkologischer Therapien dargelegt und Aufnahmestrategien für Patienten mit malignen Erkrankungen vorgestellt.

Regulation of inflammatory responses by dynamic subcellular localization of RNA-binding protein Arid5a

Adenine-thymine (AT)-rich interactive domain 5a (Arid5a) is an RNA-binding protein found in the cytoplasm and nucleus of normally growing cells. Although Arid5a is known to play an important role in immune regulation, whether and how Arid5a subcellular localization impacts immune regulation has remained unclear. In this study, we generated Arid5a transgenic (TG) mice to address this question. While ectopic Arid5a overexpression did not affect expression of inflammatory cytokines under unstimulated conditions, significantly higher levels of inflammatory cytokines, such as IL-6, were produced in response to lipopolysaccharide (LPS) stimulation. Consistent with this, TG mice were more sensitive to LPS treatment than wild-type mice. We also found that Arid5a is imported into the nucleus via a classical importin-α/β1-mediated pathway. On stimulation, nuclear Arid5a levels were decreased, while there was a concomitant increase in cytoplasmic Arid5a. Arid5a is associated with up-frameshift protein 1, and its nuclear export is regulated by a nuclear export receptor, chromosomal region maintenance 1. Taken together, these data indicate that Arid5a is a dynamic protein that translocates to the cytoplasm from the nucleus so as to properly exert its dual function in mRNA stabilization and transcriptional regulation during inflammatory conditions.

WITHDRAWN: IFN-γ and IL-1β treated-human placenta-derived mesenchymal stromal cells enhance the generation of IL-10+T cells by upregulating PDLs expressions and ameliorate experimental autoimmune encephalomyelitis

// Zhuoya Wang 1,* Weiwei Wang 1,* , Yun Hou 2 , Aiping Zhang 1 , Guoyan Wang 3 , Junzhu Yi 1 , Qiang Fu 1 and Xiying Luan 1,4 1 Department of Immunology, Binzhou Medical University, Shandong Province, Yantai, People&rsquo;s Republic of China 2 Department of Histology and Embryology, Binzhou Medical University, Shandong Province, Yantai, People&rsquo;s Republic of China 3 Department of Laboratory, Affiliated Yantai hospital of Binzhou Medical University, Yantai, People&rsquo;s Republic of China 4 Taishan Scholar Immunology program, Binzhou Medical university, Yantai, Shandong Province, People&rsquo;s Republic of China * Theses authors contributed equally to this work Correspondence to: Xiying Luan, email: xyluan@sohu.com Keywords : mesenchymal stromal cells (MSCs); IL-10+T cells; experimental autoimmune encephalomyelitis (EAE); PDLs; IFN-&gamma; Received: November 09, 2017&nbsp;&nbsp;&nbsp;&nbsp; Accepted: January 02, 2018&nbsp;&nbsp;&nbsp;&nbsp; Epub: January 09, 2018&nbsp;&nbsp;&nbsp;&nbsp; Abstract Mesenchymal stromal cells (MSCs) are regarded as promising candidates for cell-based therapies in the treatment of autoimmune and inflammation-related diseases, such as multiple sclerosis (MS), due to their immunomodulatory capacity. High levels of inflammatory cytokines represent one of the salient characteristics of MS. Obviously, there is an interplay between MSCs and inflammatory cytokines after MSCs transplantation, which may be related to the therapeutic effects of MSCs. Here, we investigate the effects of IFN-&gamma; and IL-1&beta; on the generation of IL-10 + T cell subsets mediated by human placenta-derived mesenchymal stromal cells (hPMSCs) as evaluated both in vitro and in a mouse model of experimental autoimmune encephalomyelitis (EAE). Our results demonstrated that the percent of IL-10 + T cells induced by hPMSCs was enhanced by IFN-&gamma; and IL-1&beta; through an up-regulation in the expression of programmed death ligand 1 and 2 (PDLs) in hPMSCs in vitro . IFN-&gamma; promoted the expression of PDLs via activation of IRF-1 triggered by the JAK/STAT signaling pathway. Both hPMSCs and IFN-&gamma;-pretreated hPMSCs increased the percent of IL-10 + T cells in EAE mice and further alleviated EAE symptoms as compared with the PBS treatment. The percent of CD4+IL-10 + T cells was further enhanced in EAE mice receiving IFN-&gamma;-pretreated hPMSCs as compared with mice receiving hPMSCs alone. Taken together, IFN-&gamma; and IL-1&beta; enhance the immunoregulatory capacities of hPMSCs with regard to the generation of IL-10 + T cells and, in this way, enable amplify the therapeutic effects of hPMSCs upon autoimmune diseases, such as MS.

Transcription factors early growth response gene (Egr) 2 and 3 control inflammatory responses of tolerant T cells.

IntroductionImpaired proliferation and production of IL2 are the hallmarks of experimental T cell tolerance. However, in most autoimmune diseases, auto‐reactive T cells do not display hyper proliferation, but inflammatory phenotypes.MethodsWe have now demonstrated that the transcription factors Egr2 and 3 are important for the control of inflammatory cytokine production by tolerant T cells, but not for tolerance induction.ResultsIn the absence of Egr2 and 3, T cell tolerance, as measured by impaired proliferation and production of IL2, can still be induced, but tolerant T cells produced high levels of inflammatory cytokines. Egr2 and 3 regulate expression of differentiation repressors and directly inhibit T‐bet function in T cells. Indeed, decreased expression of differentiation repressors, such as Id3 and Tcf1, and increased expression of inflammatory transcription factors, such as RORγt and Bhlhe40 were found in Egr2/3 deficient T cells under tolerogenic conditions. In addition, T‐bet was co‐expressed with Egr2 in tolerant T cells and Egr2/3 defects leads to production of high levels of IFNγ in tolerant T cells.ConclusionsOur findings demonstrated that despite impaired proliferation and IL2 production, tolerant T cells can display inflammatory responses in response to antigen stimulation and this is controlled at least partly by Egr2 and 3.

Comparison of scopolamine-induced cognitive impairment responses in three different ICR stocks

Cognitive impairment responses are important research topics in the study of degenerative brain diseases as well as in understanding of human mental activities. To compare response to scopolamine (SPL)-induced cognitive impairment, we measured altered parameters for learning and memory ability, inflammatory response, oxidative stress, cholinergic dysfunction and neuronal cell damages, in Korl:ICR stock and two commercial breeder stocks (A:ICR and B:ICR) after relevant SPL exposure. In the water maze test, Korl:ICR showed no significant difference in SPL-induced learning and memory impairment compared to the two different ICRs, although escape latency was increased after SPL exposure. Although behavioral assessment using the manual avoidance test revealed reduced latency in all ICR mice after SPL treatment as compared to Vehicle, no differences were observed between the three ICR stocks. To determine cholinergic dysfunction induction by SPL exposure, activity of acetylcholinesterase (AChE) assessed in the three ICR stocks revealed no difference of acetylcholinesterase activity. Furthermore, low levels of superoxide dismutase (SOD) activity and high levels of inflammatory cytokines in SPL-treated group were maintained in all three ICR stocks, although some variations were observed between the SPLtreated groups. Neuronal cell damages induced by SPL showed similar response in all three ICR stocks, as assessed by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay, Nissl staining analysis and expression analyses of apoptosis-related proteins. Thus, the results of this study provide strong evidence that Korl:ICR is similar to the other two ICR. Stocks in response to learning and memory capacity.

High dengue virus load differentially modulates human microvascular endothelial barrier function during early infection.

Plasma leakage is the main pathophysiological feature in severe dengue, resulting from altered vascular barrier function associated with an inappropriate immune response triggered upon infection. The present study investigated functional changes using an electric cell-substrate impedance sensing system in four (brain, dermal, pulmonary and retinal) human microvascular endothelial cell (MEC) lines infected with purified dengue virus, followed by assessment of cytokine profiles and the expression of inter-endothelial junctional proteins. Modelling of changes in electrical impedance suggests that vascular leakage in dengue-infected MECs is mostly due to the modulation of cell-to-cell interactions, while this loss of vascular barrier function observed in the infected MECs varied between cell lines and DENV serotypes. High levels of inflammatory cytokines (IL-6 and TNF-α), chemokines (CXCL1, CXCL5, CXCL11, CX3CL1, CCL2 and CCL20) and adhesion molecules (VCAM-1) were differentially produced in the four infected MECs. Further, the tight junctional protein, ZO-1, was down-regulated in both the DENV-1-infected brain and pulmonary MECs, while claudin-1, PECAM-1 and VE-cadherin were differentially expressed in these two MECs after infection. Non-purified virus stock was also studied to investigate the impact of virus stock purity on dengue-specific immune responses, and the results suggest that virus stock propagated through cell culture may include factors that mask or alter the DENV-specific immune responses of the MECs. The findings of the present study show that high DENV load differentially modulates human microvascular endothelial barrier function and disrupts the function of inter-endothelial junctional proteins during early infection with organ-specific cytokine production.

T Cell-Derived CD70 Delivers an Immune Checkpoint Function in Inflammatory T Cell Responses.

The CD27-CD70 pathway is known to provide a costimulatory signal, with CD70 expressed on APCs and CD27 functions on T cells. Although CD70 is also expressed on activated T cells, it remains unclear how T cell-derived CD70 affects T cell function. Therefore, we have assessed the role of T cell-derived CD70 using adoptive-transfer models, including autoimmune inflammatory bowel disease and allogeneic graft-versus-host disease. Surprisingly, compared with wild-type T cells, CD70-/- T cells caused more severe inflammatory bowel disease and graft-versus-host disease and produced higher levels of inflammatory cytokines. Mechanistic analyses reveal that IFN-γ induces CD70 expression in T cells, and CD70 limits T cell expansion via a regulatory T cell-independent mechanism that involves caspase-dependent T cell apoptosis and upregulation of inhibitory immune checkpoint molecules. Notably, T cell-intrinsic CD70 signaling contributes, as least in part, to the inhibitory checkpoint function. Overall, our findings demonstrate for the first time, to our knowledge, that T cell-derived CD70 plays a novel immune checkpoint role in inhibiting inflammatory T cell responses. This study suggests that T cell-derived CD70 performs a critical negative feedback function to downregulate inflammatory T cell responses.

Pulmonary Iron Homeostasis in Hepcidin Knockout Mice.

Pulmonary iron excess is deleterious and contributes to a range of chronic and acute inflammatory diseases. Optimal lung iron concentration is maintained through dynamic regulation of iron transport and storage proteins. The iron-regulatory hormone hepcidin is also expressed in the lung. In order to better understand the interactions between iron-associated molecules and the hepcidin-ferroportin axis in lung iron balance, we examined lung physiology and inflammatory responses in two murine models of systemic iron-loading, either hepcidin knock-out (Hepc KO) or liver-specific hepcidin KO mice (Hepc KOliv), which do (Hepc KOliv) or do not (Hepc KO) express lung hepcidin. We have found that increased plasma iron in Hepc KO mice is associated with increased pulmonary iron levels, consistent with increased cellular iron uptake by pulmonary epithelial cells, together with an increase at the apical membrane of the cells of the iron exporter ferroportin, consistent with increased iron export in the alveoli. Subsequently, alveolar macrophages (AM) accumulate iron in a non-toxic form and this is associated with elevated production of ferritin. The accumulation of iron in the lung macrophages of hepcidin KO mice contrasts with splenic and hepatic macrophages which contain low iron levels as we have previously reported. Hepc KOliv mice with liver-specific hepcidin deficiency demonstrated same pulmonary iron overload profile as the Hepc KO mice, suggesting that pulmonary hepcidin is not critical in maintaining local iron homeostasis. In addition, the high iron load in the lung of Hepc KO mice does not appear to enhance acute lung inflammation or injury. Lastly, we have shown that intraperitoneal LPS injection is not associated with pulmonary hepcidin induction, despite high levels of inflammatory cytokines. However, intranasal LPS injection stimulates a hepcidin response, likely derived from AM, and alters pulmonary iron content in Hepc KO mice.

Transcription factors Nrf2 and NF-κB contribute to inflammation and apoptosis induced by intestinal ischemia-reperfusion in mice

Intestinal ischemia/reperfusion (IIR) is a common pathological event associated with intestinal injury and apoptosis with high mortality. Nuclear factor (NF)-E2-related factor-2 (Nrf2) is a key transcription factor that interacts with NF-κB and has a vital anti-inflammatory effect. However, whether Nrf2 has a role in IIR-induced apoptosis and the possible underlining mechanisms, such as modulation of the inflammation regulation pathway, have remained to be fully elucidated. In the present study, IIR was identified to cause significant intestinal injury and apoptosis, with high expression levels of inflammatory cytokines, as well as the apoptotic proteins B-cell lymphoma 2 (Bcl-2)-associated X protein (Bax) and caspase-3, while simultaneously decreasing the protein levels of Bcl-2. The effect was more pronounced after pretreatment of the animals with all-trans retinoic acid or brusatol, potent inhibitors of Nrf2. t-Butylhydroquinone, an Nrf2 activator, significantly attenuated IIR-induced intestinal injury and apoptosis, with inhibition of the overexpression of the inflammatory cytokines, Bax and caspase-3 protein and partial restoration of Bcl-2 protein expression. Taken together, these results indicated that increased Nrf2 expression reduced IIR-induced intestinal apoptosis and that the protective function of Nrf2 may be based on its anti-inflammatory effects through the inhibition of the NF-κB pathway.

TNF\u03b1 deficiency results in increased IL-1\u03b2 in an early onset of spontaneous murine colitis

Inflammatory bowel disease (Crohn’s disease (CD) and ulcerative colitis (UC)) is a multifactorial disease resulting from immune dysregulation in the gut. The underlying colitis is characterized by high levels of inflammatory cytokines, including TNFα. Biological intervention for IBD patients using anti-TNFα antibodies is often an effective therapeutic solution. However, TNFα neutralization fails to induce remission in a subgroup of IBD patients, primarily in UC patients. There is a dearth of suitable animal models representing TNFα non-responders. Here we have combined one of the best UC models currently available, namely Winnie and the TNFαKO mouse to generate a TNFα-deficient Winnie to study early onset colitis. The induced TNFα deficiency with underlying colitis does not influence general health (viability and body weight) or clinical parameters (colon weight, colon length and histological colitis) when compared with the Winnie genotype alone. The molecular characterization resulted in identification of Il1β as the major elevated cytokine during early phases of colitis. Further, in vitro functional assay using bone marrow-derived dendritic cells confirmed IL-1β as the major cytokine released in the absence of TNFα. This study has generated a successful model of colitis that remains TNFα non-responsive and has demonstrated that IL-1β expression is a major pathway for the progression of colitis in this system. These data also suggest that IL-1β can be a potential target for clinical intervention of UC patients who fail to respond to TNFα neutralization.