Irma Airoldi

IRCCS Istituto G. Gaslini, Genova, Liguria, Italy

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Publications (90)561.38 Total impact

  • I Airoldi · A. Bertaina · I Prigione
    No preview · Article · Mar 2016 · Blood
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    [Show abstract] [Hide abstract] ABSTRACT: IL-27 is a member of the IL-12 family that is produced by macrophages and dendritic cells. IL-27 inhibits the growth and invasiveness of different cancers and therefore represents a potential anti-tumor agent. By contrast, it may exert immune-regulatory properties in different biological systems. We reported that IL-27 induces the expression of the IL-18 inhibitor IL-18BP, in human Epithelial Ovarian Cancer (EOC) cells, thus potentially limiting the immune response. Here, we tested whether IL-27 may modulate other immune-regulatory molecules involved in EOC progression, including Indoleamine 2,3-dioxygenase (IDO) and Programmed Death-Ligand (PD-L)1. IDO and PD-L1 were not constitutively expressed by EOC cells in vitro, but IL-27 increased their expression through STAT1 and STAT3 tyrosine phosphorylation. Differently, cells isolated from EOC ascites showed constitutive activation of STAT1 and STAT3 and IDO expression. These findings, together with the expression of IL-27 in scattered leukocytes in EOC ascites and tissues, suggest a potential role of IL-27 in immune-regulatory networks of EOC. In addition, IL-27 induced IDO or PD-L1 expression in monocytes and in human PC3 prostate and A549 lung cancer cells. A current paradigm in tumor immunology is that tumor cells may escape from immune control due to "adaptive resistance" mediated by T cell-secreted IFN-γ, which induces PD-L1 and IDO expression in tumor cells. Our present data indicate that also IL-27 has similar activities and suggest that the therapeutic use of IL-27 as anti-cancer agent may have dual effects, in some tumors.
    Preview · Article · Dec 2015 · Oncotarget
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    [Show abstract] [Hide abstract] ABSTRACT: The anti-tumoral effect of lenalidomide is increased in vivo by hypoxia-inducible factor (HIF)-1α inhibition in myeloma cells We investigated the effect of stable suppression of hypoxia inducible factor (HIF)-1α in myeloma cells on sensitivity to lenalidomide (LEN) in vivo. We found that the in vivo anti-tumoral effect of LEN is enhanced by HIF-1α suppression in myeloma cells. It has been reported that HIF-1α is over-expressed by myeloma cells 1-4 and that HIF-1α suppression significantly blocks myeloma-induced angiogenesis, and reduces both tumoral burden and bone destruction in vivo in multiple myeloma (MM) mouse models. 3 The potential effects of HIF-1α modulation on drug sensitivity in MM cells are not known and are currently under investigation. The immunomodulatory drugs (IMiDs®), including LEN, are a class of drugs derived from thalidomide 4 able to exert anti-myeloma effects by the selective Cereblon-dependent destruction of IKZF proteins, 5,6 either through a direct action on MM cell proliferation and survival, 7 or through indirect immunomodulatory and anti-angiogenic effects. 7 Previous data indicated that HIF-1α inhibition did not increase the anti-proliferative in vitro effect of bortezomib on MM cells; 2,3 this drug induces a strong downregula-tion of HIF-1α in MM cells. 2 We recently reported that HIF-1α knockdown in the human myeloma cell line (HMCL) JJN3 potentiated the in vitro effect of LEN treatment (48-72 h) on cell proliferation through a significant upregulation of p27 without changing cell viability. 3 It has been consistently reported that LEN only slightly down-regulated HIF-1α expression in MM cells. 2 Such evidence has provided the rationale to investigate the effect of stable suppression of HIF-1α in myeloma cells on LEN sensitivity in vivo. Therefore, in the present study, we first inhibited HIF-1α in three HMCLs (JJN3, OPM2 and H929) using an anti-HIF1α lentiviral shRNA pool, as previously described. 3 H929 showed a very high mortality rate after anti-HIF1α lentiviral infection (data not shown) and were not used for the subsequent in vivo experiments. We assessed the effect of LEN in combination with HIF-1α inhibition in a non-obese diabetic/severe combined immunodeficiency (NOD/SCID) subcutaneous in vivo mouse model. 3 Different groups of animals (5 animals in each group) of two sets of independent experiments were injected with JJN3 pLKO.1 (empty vector) or JJN3 anti-HIF1α. When tumors became palpable (approx. 7-10 days after injection) mice were treated with LEN 5 mg/kg (Selleckchem, Houston, TX, USA) or vehicle (DMSO) using the intraperitoneal route. The same mouse model, grouping strategy and treatment conditions were used for OPM2 pLKO.1 or OPM2 anti-HIF1α. After three weeks, we evaluated tumor volume and weight, as previously described, 3 and immunohisto-chemistry was used to evaluate the microvascular density (MVD) and checked by CD34 immunostaining (Santa Cruz, Dallas, TX, USA). 3 In addition, in the first set of mice experiments, the expression of p27 (Abcam, Cambridge, UK) was evaluated by immunohistochem-istry. The expression of S-phase kinase-associated protein 2 (SKP2), a p27 inhibitor, expression of the HIF-1α target key mediator of glycolysis and tumoral growth, Hexokinase II (HK2), and levels of pERK 1/2, and total Caspase-3 (Casp-3) were evaluated in the ex vivo plasma-cytoma lysates by western blot using the following anti-bodies: SKP2, Casp-3 (Santa Cruz, Dallas, TX, USA), HK2, pERK 1/2, (Cell Signaling, Danvers, MA, USA). b-actin was used as internal control (Millipore
    Full-text · Article · Dec 2015 · Haematologica
  • [Show abstract] [Hide abstract] ABSTRACT: In a previous study, lack of IL-12 signaling in il12rb2 knock-out mice was found to predispose to lung adenocarcinoma (LAC). We asked whether specific polymorphisms of the human IL12RB2 gene may confer susceptibility to LAC. We studied IL12RB2 single nucleotide polymorphisms (SNPs) spanning from the promoter to the first untranslated exon of the gene. Genotypes of 49 individuals with LAC were compared with those of 93 healthy subjects. Two allele variants were found to be associated with increased susceptibility to LAC. One haplotype (hap), hap18, was more frequent in patients (18%) versus controls (6%) and significantly associated with increased probability of disease occurrence. Furthermore, IL-12 driven STAT4 phosphorylation in T cell blasts from healthy individuals was found to correlate with both single allele variants and haplotypes. In conclusion, genetically determined low signaling activity of IL-12R predisposes to the development of LAC.
    No preview · Article · Nov 2015 · Immunobiology
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    [Show abstract] [Hide abstract] ABSTRACT: Critical issues in prostate cancer (PC) are a. identification of molecular drivers of the highly aggressive neuroendocrine differentiation (NED) in adenocarcinoma, and b. early assessment of disease progression. The SRY (sex determining region Y)-box 2 gene, SOX2, is an essential embryonic stem cell gene involved in prostate tumorigenesis. Here we assessed its implications in NED and progression of PC and its diagnostic and prognostic value. Laser microdissection, qRT-PCR, quantitative Methylation-Specific PCR and immunohistochemistry were used to analyze SOX2 gene expression and regulation in 206 PC samples. Results were examined according to the patient's clinical pathological profile and follow-ups. Functional studies were performed using PC cells transfected to overexpress or silence SOX2. SOX2 was consistently downregulated in PC, except in cell clusters lying within lymph node (LN)-positive PC. Multivariate analysis revealed that SOX2 mRNA expression in the primary tumor was significantly associated with LN metastasis. When SOX2 mRNA levels were ≥1.00, relative to (XpressRef) Universal Total RNA, adjusted Odds Ratio was 24.4 (95% CI: 7.54-79.0), sensitivity 0.81 (95% CI: 0.61-0.93) and specificity 0.87 (95% CI: 0.81-0.91). Patients experiencing biochemical recurrence had high median levels of SOX2 mRNA. In both PC and LN metastasis, SOX2 and NED marker, Chromogranin-A, were primarily co-expressed. In PC cells, NED genes were upregulated by SOX2 overexpression and downregulated by its silencing, which also abolished SNAI2/Slug dependent NED. Moreover, SOX2 upregulated neural CAMs, neurotrophins/neurotrophin receptors, pluripotency and epithelial-mesenchimal transition transcription factors, growth, angiogenic and lymphangiogenic factors, and promoted PC cell invasiveness and motility. This study discloses novel SOX2 target genes driving NED and spread of PC and proposes SOX2 as a functional biomarker of LN metastasization for PC.
    Full-text · Article · Nov 2015 · Oncotarget
  • [Show abstract] [Hide abstract] ABSTRACT: Background: Adenocarcinoma (AC) and Squamous Cell Carcinoma (SCC) constitute the commonest lung cancer histotypes, but current therapies still fail to significantly increase their survival rate. An effective immunotherapy to apply alternatively or together with specific treatments may be of great value. Here we asked whether Interleukin (IL)-27, which has revealed powerful antitumor activity in different tumor types and is toxicity-free in humans, is a promising therapeutic choice for NSCLC patients. Methods: Human lung AC and SCC cell lines were used to assess IL-27’s effect on cancer cell viability, by flow cytometry, and on malignancy-related gene expression, by qRT-PCR. Its effects on tumor growth were assessed in pre-clinical models and examined histopathologically. Expression of IL-27Receptor(R) in clinical samples was assessed by laser capture microdissection followed by qRT-PCR, and by immunohistochemistry. Results: In vitro, IL-27 was ineffective on cancer cell proliferation or apoptosis, but fostered CXCL3/GROg/MIP2b expression. In vitro and in vivo, IL-27 down-regulated stemness-related genes, namely SONIC HEDGEHOG in AC cells, and OCT4A, SOX2, NOTCH1, KLF4 along with the Epithelial to Mesenchymal Transition (EMT)-related genes NESTIN, SNAI1/Snail, SNAI2/Slug and ZEB1, in SCC cells. In vivo, IL-27 hampered both AC and SCC tumor growth in association with a prominent granulocyte- and macrophage-driven colliquative necrosis, CXCL3 production, and a reduced pluripotency- and EMT-related gene expression. Myeloablation of tumor-bearing hosts mostly abolished IL-27's antitumor effects. In clinical samples, IL-27R was expressed by the majority of AC, 90%, and SCC, 84%. Its expression by the primary tumor was significantly associated with advanced stages of disease (P = 0,02) as assessed by Fisher’s exact test. IL-27R was also expressed by pre-cancerous lesions, microvessels, and by infiltrating immune cells as CD15[+]granulocytes, CD68[+]monocytes/macrophages and CD11c[+]myeloid dendritic cells scattered in the stroma or within the lymph node–like structures, known as tertiary-lymphoid-structures (TLS). Conclusion: Altogether, our results highlight novel aspects of IL-27’s antitumor potential, specifically in NSCLC, such as the ability to drive myeloid cells towards antitumor activities, and down-regulate stemness genes, particularly in SCC cells, thus suppressing their self-renewal potential. IL-27 may thus be proposed for clinical trials with the prospect of its clinical use in immune-defective or advanced NSCLC patients.
    No preview · Conference Paper · Sep 2015
  • I Airoldi · C. Cocco · N. Giuliani
    No preview · Article · Jul 2015 · Blood
  • No preview · Conference Paper · Mar 2015
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    Full-text · Dataset · Feb 2015
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    [Show abstract] [Hide abstract] ABSTRACT: Prostate Cancer (PCa)-related deaths are mostly due to metastasization of poorly differentiated adenocarcinomas often endowed with neuroendocrine differentiation (NED) areas. The SNAI2/Slug gene is a major regulator of cell migration and tumor metastasization. We here assessed its biological significance in NED, and metastatic potential of PCa. SNAI2 expression was down-regulated in most PCa epithelia, in association with gene promoter methylation, except for cell clusters forming: a. the expansion/invasion front of high-grade PCa, b. NED areas, or c. lymph node metastasis. Knockdown of SNAI2 in PC3 cells down-regulated the expression of neural-tissue-associated adhesion molecules, Neural-Cadherin, Neural-Cadherin-2, Neuronal-Cell-Adhesion-Molecule, and of the NED marker Neuron-Specific Enolase, whereas it abolished Chromogranin-A expression. The metastasis-suppressor genes, Nm23-H1 and KISS1, were up-regulated, while the pluripotency genes SOX2, NOTCH1, CD44v6, WWTR1/TAZ and YAP1 were dramatically down-regulated. Over-expression of SNAI2 in DU145 cells substantiated its ability to regulate metastasis-suppressor, NED and pluripotency genes. In PCa and lymph node metastasis, expression of SOX2 and NOTCH1 was highly related to that of SNAI2. In conclusion, I. SNAI2 silencing in PCa may turn-off the expression of NED markers and pluripotency genes, while turning-on that of specific metastasis-suppressors, II. SNAI2 expression in selected PCa cells, by regulating their self-renewal, NED and metastatic potential, endows them with highly malignant properties. SNAI2 may thus constitute a key target for modern approaches to PCa progression.
    Full-text · Article · Feb 2015 · Oncotarget
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    [Show abstract] [Hide abstract] ABSTRACT: We prospectively assessed functional and phenotypic characteristics of γδ T lymphocytes up to 7 months after HLA-haploidentical hematopoietic stem cell transplantation (haplo-HSCT) depleted of αβ(+) T cells and CD19(+) B cells in 27 children with either malignant or non-malignant disorders. We demonstrate that: i) γδ T cells are the predominant T-cell population in patients during the first weeks after transplantation, being mainly, albeit not only, derived from cells infused with the graft and expanding in vivo, ii) central-memory cells predominated very early post-transplantation for both Vδ1 and Vδ2 subsets; iii) Vδ1 cells are specifically expanded in patients experiencing cytomegalovirus reactivation and are more cytotoxic compared to those of children who did not experience reactivation; iv) these subsets display a cytotoxic phenotype and degranulate when challenged with primary acute myeloid and lymphoid leukemia blasts; v) Vδ2 cells are expanded in vitro after exposure to zoledronic acid and efficiently lyse primary lymphoid and myeloid blasts. This is the first detailed characterization of γδ T cells emerging in peripheral blood of children after CD19(+) B- and αβ(+) T-cell depleted haplo-HSCT. Our results can be instrumental to the development of clinical trials using zoledronic acid for improving γδ T-cell killing capacity against leukemia cells. Copyright © 2015 American Society of Hematology.
    Full-text · Article · Jan 2015 · Blood
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    [Show abstract] [Hide abstract] ABSTRACT: Current therapies for Non-Small Cell Lung Cancer (NSCLC) still fail to significantly increase its survival rate. Here we asked whether Interleukin(IL)-27, which has revealed powerful antitumor activity and is toxicity-free in humans, is a promising therapeutic choice for NSCLC patients. IL-27's effects were tested on Adenocarcinoma (AC) and Squamous Cell Carcinoma (SCC) cell lines and xenograft models. IL-27Receptor(R) expression was assessed in lung tissues from 78 NSCLC patients. In vitro, IL-27 was ineffective on cancer cell proliferation or apoptosis, but fostered CXCL3/GROγ/MIP2β expression. In vitro and in vivo, IL-27 down-regulated stemness-related genes, namely SONIC HEDGEHOG in AC cells, and OCT4A, SOX2, NOTCH1, KLF4 along with Nestin, SNAI1/SNAIL, SNAI2/SLUG and ZEB1, in SCC cells. In vivo, IL-27 hampered both AC and SCC tumor growth in association with a prominent granulocyte- and macrophage-driven colliquative necrosis, CXCL3 production, and a reduced pluripotency- and EMT-related gene expression. Myeloablation of tumor-bearing hosts mostly abolished IL-27's antitumor effects. In clinical samples, IL-27R expression was found in AC, SCC, pre-cancerous lesions and tumor infiltrating myeloid cells, and correlated with advanced stages of disease. Our data suggest that even immunocompromised or advancer NSCLC patients may benefit from IL-27's antitumor properties based on its ability to drive myeloid cells towards antitumor activities, and down-regulate stemness- and EMT-related genes in cancer cells.
    Full-text · Article · Jan 2015 · Oncotarget
  • [Show abstract] [Hide abstract] ABSTRACT: Introduction: Prostate cancer (PCa) is a leading cause of cancer-related death in men worldwide. Understanding of immune-regulatory signals skewing PCa toward dormancy or progression is of crucial importance to identify novel targets of- or tools for- therapies. The interleukin (IL)-27 has revealed potent anti-tumor activity in a variety of tumors, but its effects on PCa is still unclear. The IL-27 cytokine subunit p28, namely IL-30, has been recognized as a novel immune-regulatory molecule, but its role in cancer biology is completely unexplored. We investigated the roles of both cytokines in PCa microenvironment and analyzed their clinical implications. Materials and methods: IL-30 and IL-27 regulation of hPCa cell viability and expression of selected gene clusters was tested by flow cytometry and PCR array. Expression of both cytokines and their receptors were assessed by immunohistochemistry and RT-PCR on prostate and draining lymph nodes from PCa patients and correlated with clinic-pathologic data. Results: In vitro, IL-30 stimulated proliferation of hPCa cells and down-regulated their expression of CCL16, LIGHT, CKLF. IL-30 consistently down-regulated the tumor suppressor and androgen co-repressor CMTM3, and up-regulated chemerinR23. In the prostate and regional lymph node tissues from PCa patients, expression of IL-30 by CD68+, CD33+/CD11b+ and CD14+ leukocytes was associated with high-grade and metastatic stage of PCa. In vitro, IL-27 inhibited proliferation and reduced the angiogenic potential of hPCa cells by down-regulating FLT1, COX-1, FGFR3 and up-regulating CXCL10 and TIMP3. In vivo, IL-27 reduced proliferation and vascularization, and promoted ischemic necrosis, of tumors developed after hPCa cell injection in nude mice. In patients’ prostate tissues, IL-27 was undetectable, while IL- 27R was expressed by normal epithelia and low grade PCa and lost by high tumor grade and stages. IL-27R was also expressed by CD11c+, CD4+ and CD8+ leukocytes infiltrating PCa and draining lymph nodes. Conclusions: IL-30 supports PCa cell growth and its expression in PCa tissue is associated with advanced disease grade and stage. IL-30 may thus constitute a valuable target for modern therapeutic approaches to PCa progression. By contrast, IL-27 exerts direct anti-proliferative and anti-angiogenic effects on PCa cells, in addition to its immune-stimulatory effects, and may be of great value to rescue from prostatectomy patients with low grade, organ confined PCa.
    No preview · Conference Paper · Sep 2014
  • [Show abstract] [Hide abstract] ABSTRACT: Introduction: Despite advances in the clinical management, lung cancer mortality has remained largely unchanged over the past three decades, underlying the need for new treatment strategies. Interleukin (IL)-27 has revealed potent anti-tumor effects in various tumor models and, importantly, freedom from toxicity in preclinical trials. We thus investigated whether IL-27 may function as anti-tumor agent in lung cancer. Materials and methods: Non small cell lung cancer cell lines Calu6 and SK-MES were selected, on the basis of their expression of IL-27R, to assess IL-27 anti-tumor activity both in vitro and in vivo. These cell lines were injected s.c. in immune deficient mice, that were treated with hrIL-27, to investigate in vivo effects of the cytokine on tumor growth and development. Expression of IL-27/IL-27R was also assessed in surgical samples from lung cancer patients. Results: In vitro, IL-27 treatment had no significant effects on proliferation and apoptosis of both cell lines. In SK-MES cells, typically endowed with spindle cell morphology, IL-27 significantly down-regulated expression of specific pluripotency and Epithelial-to-Mesenchimal-Transition (EMT) transcription factors. In both SK-MES and Calu-6 cell lines, IL-27 up-regulated the expression of the powerful granulocyte chemoattractant CXCL3. In SK-MES cells only, IL-27 also up-regulated IFN-g and down-regulated trombospondin-1 and laminin-a5 expression. In vivo, IL-27 reduced the growth of both Calu-6 and SK-MES tumors in association with areas of colliquative necrosis, a prominent infiltrate of granulocytes and macrophages, while a slight anti-angiogenic effect was detected particularly in SK-MES tumors. Myeloablative conditioning of tumor bearing mice greatly reduced the in vivo efficacy of IL-27, even if in the SK-MES tumors the phenotypic alterations associated with EMT down-regulation were still evident. Finally, in patients’ lung cancer tissues, IL-27R was mainly expressed by stromal infiltrating immune cells and often by tumor cells in both adenocarcinomas and squamous cell lung cancers. Conclusions: Our results highlight novel aspects of IL-27 anti-tumor activity such as I. the capability to orchestrate myeloid cell re-education towards anti-cancer activities and, II. down-regulate the expression of pluripotency and EMT related genes. These findings together with the evidence of IL-27R expression in lung cancer microenvironment strongly candidate this cytokine for its clinical use.
    No preview · Conference Paper · Sep 2014
  • [Show abstract] [Hide abstract] ABSTRACT: Introduction: Prostate cancer (PCa)- related deaths are mostly due to metastatic diseases developed from high grade cancers often endowed with neuroendocrine differentiation (NED) areas. SNAI2/Slug is a zinc-finger transcription factor that acts as a key regulator of cell migration during both embryonic development and tumor metastatization. Its role in prostate cancer development and progression is not yet fully understood. We thus investigated SNAI2 gene expression, regulation and role in human PCa. Materials and methods: Epithelium and stroma were microdissected from PCa specimens and then analysed by real-time RT-PCR to detect SNAI2 gene expression levels in both compartments. Immunostainings was used to localize the expression of SNAI2 protein and that of its down-stream target molecules in prostate samples. Genomic sequencing was performed to assess the involvement of epigenetic mechanisms in the SNAI2 gene expression regulation, while knockdown of SNAI2, by specific siRNA, was performed to clarify its biological role. Results: SNAI2 expression was considerably down-regulated in most malignant epithelia, microdissected from PCa samples, in association with gene promoter methylation, with the exception of few cancer foci and cell clusters forming: I. Chromogranin-A+ neuroendocrine differentiation (NED) areas, II. the expansion/invasion front of high-grade PCa or, III. lymph-node metastasis. SNAI2 was methylated in 22Rv1 and LNCaP cell lines and treatment with 5-aza-2’-deoxycytidine restored its expression, but not in PC3 cells. Depletion of SNAI2 mRNA by siRNA, in the latter cell line, increased expression levels of E-Cadh and Ep-CAM, while down-regulated the expression of N-Cadh and NED markers such as Chromogranin-A, Neuron-Specific-Enolase, Nr-CAM and N-Cadh 2. The pluripotency genes SOX2, OCT4A and NOTCH1 were also down-regulated, while the metastasis-suppressor genes KISS1 and Nm23-H1 were up-regulated. In patient’s samples, the expression SNAI2 protein was related directly to that of SOX2, OCT4A and NOTCH1 and, inversely to that of Nm23-H1. Conclusions: SNAI2 is expressed in selected PCa areas. Silencing of SNAI2, in most PCa epithelia, may turn off the expression of NED markers and pluripotency genes, while turn on that of metastasis-suppressor genes. These data by enlightening its role in shaping differentiation and metastatic potential of PCa, candidate SNAI2 as key therapeutic target to hamper PCa progression.
    No preview · Conference Paper · Sep 2014
  • No preview · Article · Jun 2014 · Journal of Clinical Investigation
  • No preview · Conference Paper · Jun 2014
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    Fabio Morandi · Irma Airoldi · Vito Pistoia
    [Show abstract] [Hide abstract] ABSTRACT: HLA-G and HLA-E are HLA-Ib molecules with several immunoregulatory properties. Their cell surface expression can be modulated by different cytokines. Since IL-27 and IL-30 may either stimulate or regulate immune responses, we have here tested whether these cytokines may modulate HLA-G and -E expression and function on human monocytes. Monocytes expressed gp130 and WSX-1, the two chains of IL27 receptor (R), and IL6R α (that serves as IL-30R, in combination with gp130). However, only IL27R appeared to be functional, as witnessed by IL-27 driven STAT1/ STAT3 phosphorylation. IL-27, but not IL-30, significantly upregulated HLA-E (but not HLA-G) expression on monocytes. IFN- γ ; secretion by activated NK cells was dampened when the latter cells were cocultured with IL-27 pretreated autologous monocytes. Such effect was not achieved using untreated or IL-30 pretreated monocytes, thus indicating that IL-27 driven HLA-E upregulation might be involved, possibly through the interaction of this molecule with CD94/NKG2A inhibitory receptor on NK cells. In contrast, cytotoxic granules release by NK cell in response to K562 cells was unaffected in the presence of IL-27 pretreated monocytes. In conclusion, we delineated a novel immunoregulatory function of IL-27 involving HLA-E upregulation on monocytes that might in turn indirectly impair some NK cell functions.
    Full-text · Article · Mar 2014 · Journal of Immunology Research
  • No preview · Conference Paper · Mar 2014
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    [Show abstract] [Hide abstract] ABSTRACT: Different cytokines play crucial roles in inflammation and in polarizing immune responses, including IL-27 that exerts pro- and anti-inflammatory functions. Although the activity of IL-27 is well characterized in murine immune cells, only limited information is available regarding the natural cellular sources of IL-27 in humans and its effects on human immune cells. Dendritic cells (DCs) are the most potent professional APCs that in the immature state are positioned throughout peripheral tissues by acting as sentinels, sensing the presence of Ags. Activated DCs migrate into the lymph nodes and direct Ag-specific T cell responses, thus acting as key players in both adaptive and innate immunity. In this study we asked whether IL-27 is produced by human secondary lymphoid organs and what is its functional role on human DCs. To our knowledge, we provide the first evidence that 1) in lymph nodes, macrophages are the major source for IL-27; 2) immature and mature human DCs express functional IL-27R; 3) IL-27 exerts immunosuppressive activity by crippling the Ag processing machinery in immature DCs under steady-state conditions and after pulsing with a viral Ag; and 4) IL-27 is chemotactic for human DCs. Our findings highlight novel mechanisms underlying the immunosuppressive activity of IL-27, suggesting that this cytokine may function as a homeostatic cytokine in secondary lymphoid organs by limiting duration and/or intensity of ongoing adaptive immune responses. The results presented in this study pave the way to future studies aimed at investigating whether dysregulation of IL-27 expression and function may be involved in pathogenesis of autoimmune disease and cancer.
    Preview · Article · Feb 2014 · The Journal of Immunology