Characterization of Long Non-Coding RNAs in Systemic Sclerosis Monocytes: A Potential Role for PSMB8-AS1 in Altered Cytokine Secretion.

Systemic sclerosis (SSc) is a chronic autoimmune disease mainly affecting the connective tissue. In SSc patients, monocytes are increased in circulation, infiltrate affected tissues, and show a pro-inflammatory activation status, including the so-called interferon (IFN) signature. We previously demonstrated that the dysregulation of the IFN response in SSc monocytes is sustained by altered epigenetic factors as well as by upregulation of the long non-coding RNA (lncRNA) NRIR. Considering the enormously diverse molecular functions of lncRNAs in immune regulation, the present study investigated the genome-wide profile of lncRNAs in SSc monocytes, with the aim to further unravel their possible role in monocyte dysregulation and disease pathogenesis. Transcriptomic data from two independent cohorts of SSc patients identified 886 lncRNAs with an altered expression in SSc monocytes. Differentially expressed lncRNAs were correlated with neighboring protein coding genes implicated in the regulation of IFN responses and apoptotic signaling in SSc monocytes. In parallel, gene co-expression network analysis identified the lncRNA PSMB8-AS1 as a top-ranking hub gene in co-expression modules implicated in cell activation and response to viral and external stimuli. Functional characterization of PSMB8-AS1 in monocytes demonstrated that this lncRNA is involved in the secretion of IL-6 and TNFα, two pivotal pro-inflammatory cytokines altered in the circulation of SSc patients and associated with fibrosis and disease severity. Collectively, our data showed that lncRNAs are linked to monocyte dysregulation in SSc, and highlight their potential contribution to disease pathogenesis.

Identification of a miR-146b-Fas ligand axis in the development of neutropenia in T large granular lymphocyte leukemia.

Tlarge granular lymphocyte leukemia (T-LGLL) is characterized by the expansion of several large granular lymphocyte clones, among which a subset of large granular lymphocytes showing constitutively activated STAT3, a specific CD8+/CD4- phenotype and the presence of neutropenia has been identified. Although STAT3 is an inducer of transcription of a large number of oncogenes, so far its relationship with miRNAs has not been evaluated in T-LGLL patients. Here, we investigated whether STAT3 could carry out its pathogenetic role in T-LGLL through an altered expression of miRNAs. The expression level of 756 mature miRNA was assessed on purified T large granular lymphocytes (T-LGLs) by using a TaqMan Human microRNA Array. Hierarchical Clustering Analysis of miRNA array data shows that the global miRNome clusters with CD8 T-LGLs. Remarkably, CD8 T-LGLs exhibit a selective and STAT3-dependent repression of miR-146b expression, that significantly correlated with the absolute neutrophil counts and inversely correlated with the expression of Fas ligand (FasL), that is regarded as the most relevant factor in the pathogenesis of neutropenia. Experimental evidence demonstrates that the STAT3-dependent reduction of miR-146b expression in CD8 T-LGLs occurs as a consequence of miR-146b promoter hypermethylation and results in the disruption of the HuR-mediated post-transcriptional machinery controlling FasL mRNA stabilization. Restoring miR-146b expression in CD8 T-LGLs lead to a reduction of HuR protein and, in turn, of FasL mRNA expression, thus providing mechanistic insights for the existence of a STAT3-miR146b-FasL axis and neutropenia in T-LGLL.

Histone modifications underlie monocyte dysregulation in patients with systemic sclerosis, underlining the treatment potential of epigenetic targeting.

BACKGROUND AND OBJECTIVE: Systemic sclerosis (SSc) is a severe autoimmune disease, in which the pathogenesis is dependent on both genetic and epigenetic factors. Altered gene expression in SSc monocytes, particularly of interferon (IFN)-responsive genes, suggests their involvement in SSc development. We investigated the correlation between epigenetic histone marks and gene expression in SSc monocytes. METHODS: Chromatin immunoprecipitation followed by sequencing (ChIPseq) for histone marks H3K4me3 and H3K27ac was performed on monocytes of nine healthy controls and 14 patients with SSc. RNA sequencing was performed in parallel to identify aberrantly expressed genes and their correlation with the levels of H3K4me3 and H3K27ac located nearby their transcription start sites. ChIP-qPCR assays were used to verify the role of bromodomain proteins, H3K27ac and STATs on IFN-responsive gene expression. RESULTS: 1046 and 534 genomic loci showed aberrant H3K4me3 and H3K27ac marks, respectively, in SSc monocytes. The expression of 381 genes was directly and significantly proportional to the levels of such chromatin marks present near their transcription start site. Genes correlated to altered histone marks were enriched for immune, IFN and antiviral pathways and presented with recurrent binding sites for IRF and STAT transcription factors at their promoters. IFNα induced the binding of STAT1 and STAT2 at the promoter of two of these genes, while blocking acetylation readers using the bromodomain BET family inhibitor JQ1 suppressed their expression. CONCLUSION: SSc monocytes have altered chromatin marks correlating with their IFN signature. Enzymes modulating these reversible marks may provide interesting therapeutic targets to restore monocyte homeostasis to treat or even prevent SSc.

Negative regulation of Toll-like receptor 4 signaling by IL-10-dependent microRNA-146b.

Toll-like receptors (TLRs) play key roles in detecting pathogens and initiating inflammatory responses that, subsequently, prime specific adaptive responses. Several mechanisms control TLR activity to avoid excessive inflammation and consequent immunopathology, including the anti-inflammatory cytokine IL-10. Recently, several TLR-responsive microRNAs (miRs) have also been proposed as potential regulators of this signaling pathway, but their functional role during the inflammatory response still is incompletely understood. In this study, we report that, after LPS engagement, monocytes up-regulate miR-146b via an IL-10-mediated STAT3-dependent loop. We show evidence that miR-146b modulates the TLR4 signaling pathway by direct targeting of multiple elements, including the LPS receptor TLR4 and the key adaptor/signaling proteins myeloid differentiation primary response (MyD88), interleukin-1 receptor-associated kinase 1 (IRAK-1), and TNF receptor-associated factor 6 (TRAF6). Furthermore, we demonstrate that the enforced expression of miR-146b in human monocytes led to a significant reduction in the LPS-dependent production of several proinflammatory cytokines and chemokines, including IL-6, TNF-α, IL-8, CCL3, CCL2, CCL7, and CXCL10. Our results thus identify miR-146b as an IL-10-responsive miR with an anti-inflammatory activity based on multiple targeting of components of the TLR4 pathway in monocytes and candidate miR-146b as a molecular effector of the IL-10 anti-inflammatory activity.

IL-10 disrupts the Brd4-docking sites to inhibit LPS-induced CXCL8 and TNF-α expression in monocytes: Implications for chronic obstructive pulmonary disease.

BACKGROUND: IL-10 is well known for its ability to block the expression and production of numerous proinflammatory cytokines, in this manner preventing the development of excessive or chronic immune activation. IL-10-induced transcriptional repression of CXCL8 and TNFA genes consists of 2 distinct phases: an early phase, occurring rapidly and in a protein synthesis-independent manner, followed by a second phase that is more delayed and dependent on protein synthesis. OBJECTIVE: We sought to identify the mechanisms through which IL-10 rapidly and directly suppresses LPS-induced CXCL8 and TNF-α transcription, which might be defective under pathologic conditions. METHODS: The molecular events triggered by IL-10 in LPS-activated monocytes at the CXCL8 and TNFA loci were investigated by using the chromatin immunoprecipitation assay. RESULTS: Inhibition of LPS-induced CXCL8 and TNF-α expression by IL-10 proceeds through a common mechanism targeting LPS-induced phosphorylation of the nuclear factor κB p65 serine 276 residue (pS276p65). As a result, all the pS276p65-dependent events occurring at the CXCL8 and TNFA loci are consistently reduced, ultimately leading to a reduction in transcript elongation. Additionally, IL-10 selectively controls CXCL8 transcript elongation through histone deacetylase (HDAC) 2-dependent covalent chromatin modifications, disrupting the assembly of the transcriptional machinery. Remarkably, PBMCs from patients with acute-phase chronic obstructive pulmonary disease, which express negligible HDAC2 levels, are scarcely affected by IL-10 in terms of inhibition of CXCL8 expression. CONCLUSIONS: This study provides mechanistic evidence that IL-10 creates a chromatin environment that decreases the transcriptional rate of CXCL8 and TNF-α to Toll-like receptor 4-activating signals. Data identify novel molecular targets for therapeutic strategies aimed at dampening inflammation in pathologies such as chronic obstructive pulmonary disease, in which reduced intracellular HDAC2 levels have been described.

Cutting edge: An inactive chromatin configuration at the IL-10 locus in human neutrophils.

To identify the molecular basis of IL-10 expression in human phagocytes, we evaluated the chromatin modification status at their IL-10 genomic locus. We analyzed posttranslational modifications of histones associated with genes that are active, repressed, or poised for transcriptional activation, including H3K4me3, H4Ac, H3K27Ac, and H3K4me1 marks. Differently from autologous IL-10-producing monocytes, none of the marks under evaluation was detected at the IL-10 locus of resting or activated neutrophils from healthy subjects or melanoma patients. By contrast, increased H3K4me3, H4Ac, H3K4me1, and H3K27Ac levels were detected at syntenic regions of the IL-10 locus in mouse neutrophils. Altogether, data demonstrate that human neutrophils, differently from either monocytes or mouse neutrophils, cannot switch on the IL-10 gene because its locus is in an inactive state, likely reflecting a neutrophil-specific developmental outcome. Implicitly, data also definitively settle a currently unsolved issue on the capacity of human neutrophils to produce IL-10.

IL-10-induced microRNA-187 negatively regulates TNF-α, IL-6, and IL-12p40 production in TLR4-stimulated monocytes.

IL-10 is a potent anti-inflammatory molecule that, in phagocytes, negatively targets cytokine expression at transcriptional and posttranscriptional levels. Posttranscriptional checkpoints also represent the specific target of a recently discovered, evolutionary conserved class of small silencing RNAs known as "microRNAs" (miRNAs), which display the peculiar function of negatively regulating mRNA processing, stability, and translation. In this study, we report that activation of primary human monocytes up-regulates the expression of miR-187 both in vitro and in vivo. Accordingly, we identify miR-187 as an IL-10-dependent miRNA playing a role in IL-10-mediated suppression of TNF-α, IL-6, and the p40 subunit of IL-12 (IL-12p40) produced by primary human monocytes following activation of Toll-like receptor 4 (TLR4). Ectopic expression of miR-187 consistently and selectively reduces TNFα, IL-6, and IL-12p40 produced by LPS-activated monocytes. Conversely, the production of LPS-induced TNF-α, IL-6, and IL-12p40 is increased significantly when miR-187 expression is silenced. Our data demonstrate that miR-187 directly targets TNF-α mRNA stability and translation and indirectly decreases IL-6 and IL-12p40 expression via down-modulation of IκBζ, a master regulator of the transcription of these latter two cytokines. These results uncover an miRNA-mediated pathway controlling cytokine expression and demonstrate a central role of miR-187 in the physiological regulation of IL-10-driven anti-inflammatory responses.

Optimizing the purification and analysis of miRNAs from urinary exosomes.

BACKGROUND: Exosomes are cytoplasm containing vesicles released by many cells that can be found in several biological fluids including urine. Urinary exosomes are released from every segment of the nephron, are detectable in urine, constitutively contain RNA (small RNAs and mRNAs) and harbor unique subset of proteins, reflecting their cellular source. METHODS: With the aim of establishing the optimal protocol for high throughput analysis of exosomal miRNAs, we compared three different urinary exosomes isolation methods and six RNA extraction techniques. Exosomal RNA yield, size and quality were assessed respectively by specific staining with fluorescent dye, capillary electrophoresis and analysis of spectrophotometric parameters. MiRNAs detection and abundance was determined by RT-qPCR. RESULTS: Among the exosomes isolation methods, Ultrafiltration resulted to be the most suited. The highest exosomal RNA yield quantified by RiboGreen® staining was obtained with the combination of TRI Reagent™ with miRNeasy®, followed by TRI Reagent™, SeraMir™, miRCURY™, mirVana™ and miRNeasy®; but after a multivariate analysis, SeraMir™ scored as the method of choice in terms of miRNA yield, purity and RT-qPCR miRNAs quantification accuracy. Storage conditions were also analyzed, showing that the relative abundance of urinary exosomal miRNAs is not influenced by urine freezing. CONCLUSIONS: The selection of appropriate urinary exosomal miRNA isolation method was dependent on various validation results. Ultrafiltration in combination with SeraMir™ exoRNA columns represents the optimal procedure for a rapid, cost-effective and efficient purification of miRNAs from urinary exosomes, perfectly suited for further applicative research in the field of miRNAs in kidney physiology and pathology.

IFN-ß expression is directly activated in human neutrophils transfected with plasmid DNA and is further increased via TLR-4-mediated signaling.

Upon LPS binding, TLR4 activates a MyD88-dependent pathway leading to the transcriptional activation of proinflammatory genes, as well as a MyD88-independent/TRIF-dependent pathway, responsible for the transcriptional induction of IFN-ß. Previous findings delineated that human neutrophils are unable to induce the transcription of IFN-ß in response to TLR4 stimulation. Because neutrophils do not express protein kinase C ε, a molecule recently reported as essential for initiating the MyD88-independent/TRIF-dependent pathway, we optimized an electroporation method to transfect PKCε into neutrophils with very high efficiency. By doing so, a significant IFN-ß mRNA expression was induced, in the absence of LPS stimulation, not only in PKCε-overexpressing neutrophils but also in cells transfected with a series of empty DNA plasmids; however, LPS further upregulated the IFN-ß transcript levels in plasmid-transfected neutrophils, regardless of PKCε overexpression. Phosphoimmunoblotting studies, as well as chromatin immunoprecipitation assays targeting the IFN-ß promoter, revealed that IFN-ß mRNA induction occurred through the cooperative action of IRF3, activated by transfected DNA, and NF-κB, activated by LPS. Additional immunoblotting and coimmunoprecipitation studies revealed that neutrophils constitutively express various cytosolic DNA sensors, including IFN-inducible protein 16, leucine-rich repeat (in Flightless I) interacting protein-1, and DDX41, as well as that IFN-inducible protein 16 is the intracellular receptor recognizing transfected DNA. Consistently, infection of neutrophils with intracellular pathogens, such as Bartonella henselae, Listeria monocytogenes, Legionella pneumophila, or adenovirus type 5, promoted a marked induction of IFN-ß mRNA expression. Taken together, these data raise questions about the role of PKCε in driving the MyD88-independent/TRIF-dependent response and indicate that human neutrophils are able to recognize and respond to microbial cytosolic DNA.

Surface CD52, CD84, and PTGER2 mark mature PMN-MDSCs from cancer patients and G-CSF-treated donors.

Precise molecular characterization of circulating polymorphonuclear myeloid-derived suppressor cells (PMN-MDSCs) is hampered by their mixed composition of mature and immature cells and lack of specific markers. Here, we focus on mature CD66b+CD10+CD16+CD11b+ PMN-MDSCs (mPMN-MDSCs) from either cancer patients or healthy donors receiving G-CSF for stem cell mobilization (GDs). By RNA sequencing (RNA-seq) experiments, we report the identification of a distinct gene signature shared by the different mPMN-MDSC populations under investigation, also validated in mPMN-MDSCs from GDs and tumor-associated neutrophils (TANs) by single-cell RNA-seq (scRNA-seq) experiments. Analysis of such a gene signature uncovers a specific transcriptional program associated with mPMN-MDSC differentiation and allows us to identify that, in patients with either solid or hematologic tumors and in GDs, CD52, CD84, and prostaglandin E receptor 2 (PTGER2) represent potential mPMN-MDSC-associated markers. Altogether, our findings indicate that mature PMN-MDSCs distinctively undergo specific reprogramming during differentiation and lay the groundwork for selective immunomonitoring, and eventually targeting, of mature PMN-MDSCs.

Severe impairment of IFN-γ and IFN-α responses in cells of a patient with a novel STAT1 splicing mutation.

Subjects affected by Signal Transducer and Activator of Transcription 1 (STAT1) deficiency have lethal bacterial and viral infections. Complete STAT1 deficiency is inherited as an autosomal recessive disease; partial STAT1 deficiency is inherited as an autosomal recessive or autosomal dominant trait. Here, we report a patient who developed disseminated mycobacteriosis early in life and had several viral infections, including herpetic skin infection and interstitial pneumonia by cytomegalovirus with severe respiratory distress. Molecular analysis of STAT1 showed a novel homozygous mutation affecting a splice site, leading to exon 3 skipping and to synthesis of a lower molecular weight STAT1 protein. This mutation leads to marked reduction of STAT1 phosphorylation; the electromobility shift assay showed a complete defect of DNA-binding activity, which accounts for the complete impairment of peripheral blood mononuclear cell functional response to both IFN-γ and IFN-α. Moreover, analysis of natural killer cells showed a defective STAT1 phosphorylation in response to IFN-α and impaired basal cytolytic activity, suggesting that the STAT1-dependent pathway might be important for natural killer cell function. These results suggested that exon 3 skipping of STAT1 leads to abnormal signaling in response to IFN-γ and IFN-α, which is associated with susceptibility to intracellular pathogens and viruses.

SH2-domain mutations in STAT3 in hyper-IgE syndrome patients result in impairment of IL-10 function.

Autosomal-dominant hyper-IgE syndrome (AD-HIES) is a primary immunodeficiency caused by STAT3 mutations. This inherited condition is characterized by eczema, staphylococcal cold abscesses and recurrent pulmonary infections. Given that STAT3 is involved in IL-10 signaling, we examined the immunoregulatory role of IL-10 in inflammation by studying the effects of IL-10 on monocytes, neutrophils and monocyte-derived DCs from HIES subjects. Analysis of gene expression in PBMCs and neutrophils isolated from HIES patients and stimulated with LPS in the presence of IL-10 showed reduced expression of IL1RN, which encodes IL-1 receptor antagonist (IL-1ra), and SOCS3 mRNA but increased CXCL8 mRNA expression. Moreover, secretion of the anti-inflammatory protein IL-1ra was reduced in AD-HIES patients. DCs from HIES patients secreted higher levels of TNF-α, IL-6 and, to a lesser extent, IL-12 when these cells were cultured in the presence of IL-10. These results suggest that IL-10 activity is affected in myeloid cells (e.g. monocytes, DCs) of HIES patients. Impairment of IL-10 signaling in patients with AD-HIES might result in an altered balance between pro-inflammatory and anti-inflammatory signals and might lead to persistent inflammation and delayed healing after infections.

Induction and regulatory function of miR-9 in human monocytes and neutrophils exposed to proinflammatory signals.

Inflammation involves a coordinated, sequential, and self limiting sequence of events controlled by positive and negative regulatory mechanisms. Recent studies have shown that microRNAs (miRNAs), an evolutionarily conserved class of endogenous 22-nucleotide noncoding RNAs, contribute to the regulation of inflammation by repressing gene expression at the posttranscriptional level. In this study, we characterize the profile of miRNAs induced by LPS in human polymorphonuclear neutrophils (PMN) and monocytes. In particular, we identify miR-9 as the only miRNA (among 365 analyzed) up-regulated in both cell types after TLR4 activation. miR-9 is also induced by TLR2 and TLR7/8 agonists and by the proinflammatory cytokines TNF-alpha and IL-1beta, but not by IFNgamma. Among the 3 different genes encoding miR-9 precursors in humans, we show that LPS selectively induces the transcription of miR-9-1 located in the CROC4 locus, in a MyD88- and NF-kappaB-dependent manner. In PMN and monocytes, LPS regulates NFKB1 at both the transcriptional and posttranscriptional levels, and a conserved miR-9 seed sustained a miR-9-dependent inhibition of the NFKB1 transcript. Overall, these data suggest that TLR4-activated NF-kappaB rapidly increases the expression of miR-9 that operates a feedback control of the NF-kappaB-dependent responses by fine tuning the expression of a key member of the NF-kappaB family.

Implementation of a combined bioinformatics and experimental approach to address lncRNA mechanism of action: The example of NRIR.

In this study, we demonstrate the benefit of applying combined strategies to analyze lncRNA action based on bioinformatics and experimental information. This strategy was developed to identify the molecular function of negative regulator of interferon response (NRIR), a type I interferon-stimulated gene (ISG), that we have previously demonstrated to be involved in the upregulation of a subset of ISGs in LPS-stimulated human monocytes. In this study, we provide experimental evidence that NRIR is localized in cellular nuclei, enriched on the chromatin fraction, and upregulates ISGs acting at the transcriptional level. In silico analysis of secondary structures identified distinct NRIR structural domains, comprising putative DNA- and protein-binding regions. In parallel, the presence of a putative DNA-binding domain in NRIR and the five putative NRIR-binding sites in the promoter of NRIR-target genes support the function of NRIR as a transcriptional regulator of its target genes. By use of integrated experimental/bioinformatics approaches, comprising database and literature mining together with in silico analysis of putative NRIR-binding proteins, we identified a list of eight transcription factors (TFs) shared by the majority of NRIR-target genes and simultaneously able to bind TF binding sites enriched in the NRIR-target gene promoters. Among these TFs, the predicted NRIR:STAT interactions were experimentally validated by RIP assay.

Understanding the molecular mechanisms of the multifaceted IL-10-mediated anti-inflammatory response: lessons from neutrophils.

Analysis of the molecular mechanisms governing the ability of IL-10 to keep inflammation under control has highlighted the existence of a great degree of plasticity and specificity with regard to innate immune cells. In this respect, neutrophils represent a perfect example of innate immune cells conditioned by external signals (for instance, by LPS), as well as by intracellular regulatory pathways, that render them optimally responsive to IL-10 only when required. The focus of this review are the recent experimental findings that have uncovered the sophisticated and complex molecular mechanisms responsible for the modulation of pro- and anti-inflammatory cytokine production by IL-10 in neutrophils and other innate immune cells. Understanding how IL-10 exerts its anti-inflammatory response, particularly in the case of neutrophils, will provide novel clues leading, hopefully, to the therapeutic control of neutrophil-driven inflammatory reactions, such as septic infections, rheumatoid arthritis, osteoarthritis and chronic obstructive pulmonary disease.

Non-food/feed seeds as biofactories for the high-yield production of recombinant pharmaceuticals.

We describe an attractive cloning system for the seed-specific expression of recombinant proteins using three non-food/feed crops. A vector designed for direct subcloning by Gateway® recombination was developed and tested in Arabidopsis, tobacco and petunia plants for the production of a chimeric form (GAD67/65) of the 65 kDa isoform of glutamic acid decarboxylase (GAD65). GAD65 is one of the major human autoantigens involved in type 1 diabetes (T1D). The murine anti-inflammatory cytokine interleukin-10 (IL-10) was expressed with the described system in Arabidopsis and tobacco, whereas proinsulin, another T1D major autoantigen, was expressed in Arabidopsis. The cost-effective production of these proteins in plants could allow the development of T1D prevention strategies based on the induction of immunological tolerance. The best yields were achieved in Arabidopsis seeds, where GAD67/65 reached 7.7% of total soluble protein (TSP), the highest levels ever reported for this protein in plants. IL-10 and proinsulin reached 0.70% and 0.007% of TSP, respectively, consistent with levels previously reported in other plants or tissues. This versatile cloning vector could be suitable for the high-throughput evaluation of expression levels and stability of many valuable and difficult to produce proteins.

Uncovering an IL-10-dependent NF-kappaB recruitment to the IL-1ra promoter that is impaired in STAT3 functionally defective patients.

The interleukin 1 receptor antagonist (IL-1ra) is an important negative regulator of the inflammatory response, whose genetic deficiency has been recently shown to cause a severe autoinflammatory syndrome in humans. In this study we characterized the molecular mechanisms whereby interleukin 10 (IL-10) potentiates IL-1ra transcription in LPS-stimulated monocytes and neutrophils. Using chromatin immunoprecipitation, we show that although NF-kappaBp65 and NF-kappaBp50 proteins accumulate into the nuclei and bind to the IkappaB alpha promoter during LPS stimulation, they are not recruited to the kappaB sites of the IL-1ra promoter. However, in response to LPS plus IL-10, which were found to induce chromatin acetylation, recruitment of both NF-kappaBp65 and NF-kappaBp50 to the IL-1ra promoter efficiently occurs in a STAT3-dependent manner. Accordingly, in neutrophils from hyper-IgE syndrome patients, who carry a nonfunctional STAT3, IL-10 failed to promote NF-kappaBp65 recruitment to the IL-1ra promoter and consequently to potentiate LPS-induced IL-1ra transcription. Altogether our findings uncover a novel mechanism whereby IL-10-activated STAT3 modulates IL-1ra transcription in LPS-treated phagocytes by making IL-1ra promoter accessible to readily available nuclear NF-kappaB.

Impact of Sex on Circulating Leukocytes Composition in COPD Patients.

PURPOSE: Chronic obstructive pulmonary disease is characterized by chronic inflammatory response both at the lung site and at the systemic level. Abnormalities in circulating leukocytes have been reported to occur in COPD patients and have been often shown to correlate with the decline in lung function. COPD affects men and women at a virtually comparable rate, even though distinct sex specific symptoms, progression and therapeutic implications have been described. Nonetheless, these sex-associated differences have not been analyzed in terms of circulating leukocytes. To assess the impact of sex on the changes of circulating immune cells in COPD patients. PATIENTS AND METHODS: Blood samples were collected from 50 COPD patients (31 males, 19 females) and 63 age and sex-matched controls (35 males, 28 females) enrolled in this pilot study. Complete blood cell count and multi-parametric flow cytometry analysis were performed to characterize the leukocyte populations and subsets. RESULTS: Male COPD patients are distinguished from controls by a significant increase in white blood cell counts, neutrophil total and differential counts, and neutrophil-to-lymphocyte ratio. Conversely, a generalized leukocyte decrease discriminated female COPD patients from the related controls. The impact of sex is further remarked by a decrease in adaptive immune cell subpopulations in males as opposed to a consistent increase of innate immune cell types in females correlating with disease severity. CONCLUSION: These data indicate that the definition of specific changes of circulating leukocytes to be used as reliable biomarkers of the disease severity cannot be accomplished irrespectively of sex.

Activation of an immunoregulatory and antiviral gene expression program in poly(I:C)-transfected human neutrophils.

Neutrophils, historically known for their involvement in acute inflammation, are also targets for infection by many different DNA and RNA viruses. However, the mechanisms by which they recognize and respond to viral components are poorly understood. Polyinosinic:polycytidylic acid (poly(I:C)) is a synthetic mimetic of viral dsRNA that is known to interact either with endosomal TLR3 (not expressed by human neutrophils) or with cytoplasmic RNA helicases such as melanoma differentiation-associated gene 5 (MDA5) and retinoic acid-inducible gene I (RIG-I). In this study, we report that intracellularly administered poly(I:C) stimulates human neutrophils to specifically express elevated mRNA levels encoding type I IFNs, immunoregulatory cytokines, and chemokines, such as TNF-alpha, IL-12p40, CXCL10, CXCL8, CCL4, and CCL20, as well as classical IFN-responsive genes (IRG), including IFIT1 (IFN-induced protein with tetratricopeptide repeats 1)/IFN-stimulated gene (ISG)56, G1P2/ISG15, PKR (dsRNA-dependent protein kinase), and IFN-regulatory factor (IRF)7. Investigations into the mechanisms whereby transfected poly(I:C) promotes gene expression in neutrophils uncovered a crucial involvement of the MAPK-, PKR-, NF-kappaB-, and TANK (TNF receptor-associated NF-kappaB kinase)-binding kinase (TBK1)/IRF3-signaling transduction pathways, as illustrated by the use of specific pharmacological inhibitors. Consistent with the requirement of the cytoplasmic dsRNA pathway for antiviral signaling, human neutrophils were found to constitutively express significant levels of both MDA5 and RIG-I, but not TLR3. Accordingly, neutrophils isolated from MDA5-deficient mice had a partial impairment in the production of IFN-beta and TNF-alpha upon infection with encephalomyocarditis virus. Taken together, our data demonstrate that neutrophils are able to activate antiviral responses via helicase recognition, thus acting at the frontline of immunity against viruses.