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Alberto Mantovani

Publications and source records attributed to Alberto Mantovani.

At least 37 records · Page 2Linked to original sources
PubMed2006

Generation and characterization of a mouse lymphatic endothelial cell line.

Lymphatic vessels, by channeling fluid and leukocytes from the periphery into lymph nodes, play a central role in the development of the immune response. Despite their importance in homeostasis and disease, the difficulties in enriching and culturing lymphatic endothelial cells limit studies of their biology. Here, we report the isolation, stabilization, and characterization of a mouse lymphatic endothelial cell line (MELC) and the generated clones thereof. Cells were isolated from benign lymphangiomas induced by intraperitoneal injections of incomplete Freund's adjuvant. The MELC line expressed molecules typical of lymphatic endothelium, including VEGFR3/Flt-4, podoplanin, Prox-1, and D6, but not LYVE-1. It also expressed CD34, ICAM-1, VCAM, and JAM-A, but not CD31, VE-cadherin, E-selectin, or CX3CL1/fractalkine (both TNFalpha-induced), at variance with vascular endothelial cells tested in parallel. The inflammatory cytokines TNFalpha and IL-4 regulated production of selected adhesion molecules (VCAM), cytokines (IL-6), and chemokines (CCL2/JE). Whole genome transcriptional profiling identified a set of 150 known genes differentially expressed in MELC versus vascular endothelial cells. Thus, the MELC line may represent an invaluable source of lymphatic endothelium.

Animals↗
PubMed2006

Tumour-associated macrophages are a distinct M2 polarised population promoting tumour progression: potential targets of anti-cancer therapy.

Tumour-associated macrophages (TAM) represent the major inflammatory component of the stroma of many tumours, and can affect different aspects of the neoplastic tissue. Many observations indicate that TAM express several M2-associated pro-tumoural functions, including promotion of angiogenesis, matrix remodelling and suppression of adaptive immunity. The pro-tumoural role of TAM in cancer is further supported by clinical studies that found a correlation between the high macrophage content of tumours and poor patient prognosis. Evidence is presented here supporting the view that TAM represent a unique and distinct M2-skewed myeloid population and are a potential target for anti-cancer therapy.

Cell Transformation, Neoplastic↗
PubMed2006

Follicular fluid levels of the long pentraxin PTX3.

OBJECTIVE: Pentraxin-3 (PTX3) is a long pentraxin that plays a key role in female fertility as a structural and essential constituent of the cumulus oophorus extracellular matrix. Despite considerable evidence supporting this role of PTX3 in mice, data in humans are scanty. The aim of the present study was (1) to evaluate follicular fluid concentrations of PTX3; (2) to test the hypothesis that levels of the molecule correlate with oocyte characteristics (corona radiata, aspect of the cumulus, nuclear maturity, and fertilization); and (3) to evaluate the possibility that peripheral concentration of PTX3 may be of clinical help in monitoring ovarian hyperstimulation. METHODS: ELISA was used to determine PTX3 concentration. Levels of PTX3 were tested in 96 follicles. RESULTS: The mean +/- SD and the median (interquartile range) were 17.9 +/- 18.3 and 12.1 (6.5-23.6) ng/mL, respectively. Levels of the molecule did not appear to be normally distributed. At the day of ovum pick-up, levels of PTX3 were 6.3-fold higher in follicular fluid than in peripheral blood (95% CI, 3.6-9.0). No statistically significant difference emerged linking follicular fluid concentration of PTX3 and oocyte quality. In a series of ten women, plasma concentration of PTX3 did not vary during ovarian hyperstimulation, resulting in levels of 1.0 +/- 0.5 at the 3rd day of the menstrual cycle and 1.0 +/- 0.6 ng/mL at the day of oocyte retrieval. CONCLUSIONS: Results from the present study support the following conclusions: (1) elevated levels of soluble PTX3 can be found in follicular fluid; (2) follicular fluid concentration of PTX3 cannot by used as a marker of oocyte quality; and (3) plasma concentration of the molecule is not influenced by ovarian hyperstimulation.

Adult↗
PubMed2006

The long pentraxin PTX3 as a link among innate immunity, inflammation, and female fertility.

The long pentraxin 3 (PTX3) is member of a complex superfamily of multifunctional proteins characterized by a cyclic multimeric structure. PTX3 is highly conserved in evolution and is produced by innate-immunity cells in response to proinflammatory signals and Toll-like receptor engagement. PTX3 plays complex, nonredundant functions in vivo, acting as a predecessor of antibodies, recognizing microbes, activating complement, facilitating pathogen recognition by phagocytes, and hence, playing a nonredundant role in resistance against selected pathogens. In addition, PTX3 is essential in female fertility by acting as a nodal point for the assembly of the cumulus oophorus hyaluronan-rich extracellular matrix. Thus, the prototypic long pentraxin PTX3 is a multifunctional, soluble pattern recognition receptor acting as a nonredundant component of the humoral arm of innate immunity and involved in matrix deposition and female fertility.

Animals↗
PubMed2006

Regulation of PTX3, a key component of humoral innate immunity in human dendritic cells: stimulation by IL-10 and inhibition by IFN-gamma.

The protopypic long pentraxin 3 (PTX3) is a unique, humoral pattern-recognition receptor, which plays a nonredundant function in innate resistance to pathogens. Dendritic cells (DC) of myelomonocytic origin, but not plasmacytoid DC, are a major source of PTX3 in response to Toll-like receptor (TLR) engagement. The present study was designed to explore the regulation of PTX3 production in DC. PTX3 production was induced by TLR ligands, CD40 ligand, and interleukin (IL)-1beta and was suppressed by dexamethasone, 1alpha, 25-dihydroxivitamin D3, and prostaglandin E2. It was unexpected that lipopolysaccharide (LPS)-stimulated PTX3 production was enhanced by IL-10 and inhibited by IL-4 and interferon-gamma (IFN-gamma). Enhancement of PTX3 production by IL-10 was also evident when Pam3 Cys-Ser-(Lys)4.3HCl, a TLR2-TLR1 agonist, polyionisicpolycytidylic acid, a TLR3 agonist, and IL-1beta were used as stimuli. The effect of IL-10 was blocked by an anti-IL-10 monoclonal antibody (mAb) or an anti-IL-10 receptor alpha mAb, which also reduced the LPS-induced production. Thus, production of PTX3 in DC is subjected to a distinct regulatory network, with inhibition by IFN-gamma and enhancement by IL-10. The amplification by IL-10 of production of a nonredundant component of fluid-phase innate immunity mirrors the IL-10 stimulatory function on B cells in adaptive immunity. As PTX3 is also an extracellular matrix component, IL-10-enhanced PTX3 production may play a role in orchestration of tissue remodeling in chronic inflammation.

Antibodies, Monoclonal↗
PubMed2006

Role of tumor-associated macrophages in tumor progression and invasion.

Tumor-Associated Macrophages (TAM) represent the major inflammatory component of the stroma of many tumors, able to affect different aspects of the neoplastic tissue. Many observations indicate that TAM express several M2-associated protumoral functions, including promotion of angiogenesis, matrix remodelling and suppression of adaptive immunity. The protumoral role of TAM in cancer is further supported by clinical studies that found a correlation between the high macrophage content of tumors and poor patient prognosis and by evidence showing that long-term use of non-steroidal anti-inflammatory drugs reduces the risk of several cancers. Here, we discuss evidence supporting the view that TAM represent a unique and distinct M2-skewed myeloid population and a potential target of anti-cancer therapy.

Animals↗
PubMed2006

Tuning inflammation and immunity by chemokine sequestration: decoys and more.

A set of chemokine receptors are structurally unable to elicit migration or conventional signalling responses after ligand engagement. These 'silent' (non-signalling) chemokine receptors regulate inflammatory and immune reactions in different ways, including by acting as decoys and scavengers. Chemokine decoy receptors recognize distinct and complementary sets of ligands and are strategically expressed in different cellular contexts. Importantly, viruses and parasites have evolved multiple strategies to elude chemokines, including the expression of decoy receptors. So, decoy receptors for chemokines represent a general strategy to tune, shape and temper innate and adaptive immunity.

Animals↗
PubMed2006

Risk assessment of endocrine disrupters: the role of toxicological studies.

Endocrine disrupters (ED) represent a good challenge for experimental toxicology. In order to deal with several critical points relevant to risk assessment: (a) ED may induce long-term effects upon exposure in susceptible developmental phases, including postnatal life up to puberty; thus, efforts are required to refine testing strategies, for example, by supporting the two-generation rodent study with a comprehensive in vitro/in vivo screening battery; (b) due to the regulatory role of endocrine homeostasis, mechanisms of endocrine disruption may impact on immune, neurobehavioral, and reproductive development, as well as on susceptibility to cancer; (c) the potential multiple exposure to ED with common targets through diet and/or living environment calls for the development of models to understand mechanisms of interactions and effects of mixtures; and (d) last but not least, ED may interact with a number of factors related to differential vulnerability of individuals or population subgroups, including the intake of nutrients or bioactive food components. Besides reducing the chance for noxious chemicals to enter our life, toxicological research on mechanisms may also lead to the definition of possible biomarkers of exposure, effect, and susceptibility that may be further exploited in human health surveillance.

Endocrine Disruptors↗
PubMed2006

Migration of dendritic cells across blood and lymphatic endothelial barriers.

Dendritic cells (DC) are professional antigen presenting cells which play a pivotal role in the activation of adaptive immunity. Tissue invasion by pathogens induces the recruitment of blood DC to the site of infection and contributes to their subsequent migration to secondary lymphoid organs. This complex process relies on the expression and regulation of receptors for chemotactic factors on the surface of migrating DC and on the activation of adhesion molecules which allow DC to properly interact with both blood and lymphatic vessels. In the absence of correct tissue localization, DC fail to promote proper immune responses. Therefore, the interaction of DC with endothelial cells represents a fundamental step for DC biology.

Animals↗
PubMed2005

Pentraxins as a key component of innate immunity.

Pentraxins are a complex superfamily of multifunctional molecules characterized by a multimeric structure. C-reactive protein and pentraxin 3 (PTX3) are prototypic molecules of the short and long pentraxin family, respectively. PTX3 is conserved in evolution and produced by innate immune cells. Evidence suggests that PTX3 acts as a non-redundant component of the humoral arm of innate immunity, downstream of, and complementary to, cellular recognition, as well as a tuner of inflammation.

Animals↗
PubMed2005

A distinct and unique transcriptional program expressed by tumor-associated macrophages (defective NF-kappaB and enhanced IRF-3/STAT1 activation).

To identify the molecular basis underlying the functions of tumor-associated macrophages (TAMs), we characterized the gene expression profile of TAMs isolated from a murine fibrosarcoma in comparison with peritoneal macrophages (PECs) and myeloid suppressor cells (MSCs), using a cDNA microarray technology. Among the differentially expressed genes, 15 genes relevant to inflammation and immunity were validated by real-time polymerase chain reaction (PCR) and protein production. Resting TAMs showed a characteristic gene expression pattern with higher expression of genes coding for the immunosuppressive cytokine IL-10, phagocytosis-related receptors/molecules (Msr2 and C1q), and inflammatory chemokines (CCL2 and CCL5) as expected, as well as, unexpectedly, IFN-inducible chemokines (CXCL9, CXCL10, CXCL16). Immunohistology confirmed and extended the in vitro analysis by showing that TAMs express M2-associated molecules (eg, IL-10 and MGL1), as well as CCL2, CCL5, CXCL9, CXCL10, and CXCL16, but no appreciable NOS2. Lipopolysaccharide (LPS)-mediated activation of TAMs resulted in defective expression of several proinflammatory cytokines (eg, IL-1beta, IL-6, TNF-alpha) and chemokines (eg, CCL3), as opposed to a strong up-regulation of immunosuppressive cytokines (IL-10, TGFbeta) and IFN-inducible chemokines (CCL5, CXCL9, CXCL10, CXCL16). Thus, profiling of TAMs from a murine sarcoma revealed unexpected expression of IFN-inducible chemokines, associated with an M2 phenotype (IL-10high, IL-12low), and divergent regulation of the NF-kappaB versus the IRF-3/STAT1 pathway.

Animals↗
PubMed2005

Role of Ca2+ in the electrostatic stability and the functional activity of the globular domain of human C1q.

C1q is the recognition subunit of the classical pathway of the complement system and a major connecting link between classical pathway-driven innate immunity and IgG- or IgM-mediated acquired immunity. The basic structural subunit of C1q is composed of an N-terminal triple-helical collagen-like region and a C-terminal heterotrimeric globular head domain (gC1q) that is made up of individual A, B, and C chains. Recent crystallographic studies have revealed that the gC1q domain, which is the main target-binding region of C1q, has a compact and spherical heterotrimeric assembly, held together by both electrostatic and nonpolar interactions, with quasi-3-fold symmetry. A characteristic feature of the gC1q domain is the presence of a exposed Ca(2+) located near the apex. We have investigated, using theoretical and experimental approaches, the role of Ca(2+) in the electrostatic stability and target-binding properties of the native C1q as well as recombinant monomeric forms of the C-terminal regions of the A, B, and C chains. Here, we report that Ca(2+) primarily influences the target recognition properties of C1q toward IgG, IgM, C-reactive protein, and pentraxin 3. At pH 7.4, the loss of Ca(2+) leads to changes in the direction of electric moment from coaxial (where the putative C-reactive protein-binding site is located) to perpendicular to the molecular axis (toward the most likely IgG-binding site), which appears important for target recognition by C1q and subsequent complement activation.

Calcium↗
PubMed2005

Gorham-Stout syndrome: a monocyte-mediated cytokine propelled disease.

UNLABELLED: We studied the biological features and the immunophenotype of a cell culture established from the lesion of soft tissues of a woman affected by Gorham-Stout syndrome. We found that these cells belonged to a monocytic lineage with some characteristics of immature osteoclasts and were able to release large amounts of osteoclastogenic and angiogenic molecules that may contribute to disease progression. INTRODUCTION: Gorham-Stout syndrome is a rare disease characterized by osteolysis and proliferation of vascular or lymphatic vessels, with a severe outcome. Its etiology and the identification of the cell types involved are completely unknown. MATERIALS AND METHODS: A cell culture from a lesion of soft tissues was established, and its behavior in vitro and in immunodeficient mice was studied. We analyzed (1) the cell phenotype by flow cytometry; (2) the adhesive and migratory properties on different substrates; (3) the ability to differentiate into mature osteoclasts; (4) the production of osteclastogenic and angiogenic molecules; (5) the in vivo angiogenic activity of the cells subcutaneously implanted in mouse in a Matrigel plug; and (6) the ability to recapitulate the disease when transplanted in nude mice. RESULTS AND CONCLUSIONS: The established culture consisted of a morphologically homogeneous cell population belonging to a monocytic lineage having some features of an osteoclast-like cell type. Cells had an invasive phenotype, were angiogenic, and produced osteoclastogenic (IL-6, TGF-beta1, IL-1beta) and angiogenic (vascular endothelial growth factor-A [VEGF-A], CXCL-8) molecules when challenged with inflammatory cytokines. Immunodeficient mice injected with these cells did not show any bone lesions or vascular alteration, but had high amounts of circulating human IL-6 and VEGF-A. Cells isolated from a cutaneous lymphangiomatosis did not show any of these findings. These data suggest that cells of monocyte-macrophage lineage play an essential role in the pathogenesis of Gorham-Stout disease, whose progression is propelled by cytokine circuits that accelerate angiogenesis and osteoclastogenesis.

Animals↗
PubMed2005

Interferon-activated neutrophils store a TNF-related apoptosis-inducing ligand (TRAIL/Apo-2 ligand) intracellular pool that is readily mobilizable following exposure to proinflammatory mediators.

Neutrophils are versatile cells, which play a role, not only in inflammatory processes but also in immune and antitumoral responses. Recently, we have reported that interferon (IFN)-activated neutrophils are able to release biologically active tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL/APO2 ligand), a molecule exerting selective, apoptotic activities toward tumor and virus-infected cells, as well as immunoregulatory functions on activated T lymphocytes. Herein, we show that only a minor fraction of the total TRAIL, newly synthesized by IFN-activated neutrophils within 24 h, is released outside, the rest being retained intracellularly, mainly in secretory vesicles and light membrane fractions. We demonstrate that the intracellular pool of TRAIL present in IFN-pretreated neutrophils is rapidly mobilizable to the cell surface and can be secreted following exposure to proinflammatory mediators such as TNF-alpha, lipopolysaccharide, formyl-methionyl-leucyl-phenylalanine, CXC chemokine ligand 8/interleukin-8, insoluble immunocomplexes, and heat shock protein Gp96. These various proinflammatory agonists functioned as effective secretagogue molecules only, in that they failed to augment TRAIL mRNA expression or TRAIL de novo synthesis in freshly isolated neutrophils or cultured with or without IFN. In addition, supernatants from IFN-treated neutrophils stimulated with proinflammatory mediators induced the apoptosis of target cells more effectively than supernatants from neutrophils activated with IFNs alone. Collectively, our results uncover a novel mechanism, whereby the release of soluble TRAIL by neutrophils can be greatly amplified and further reinforce the notion that neutrophils are important cells in tumor surveillance and immunomodulation.

Antigen-Antibody Complex↗
PubMed2005

Targeting myelomonocytic cells to revert inflammation-dependent cancer promotion.

Tumor development and progression are strongly linked to inflammation and the presence of tumor-associated macrophages (TAMs). In murine tumors, antitumor activity can be achieved by targeting TAM recruitment, survival, activation, polarization, effector signaling, or extracellular matrix interactions. Thus, it may be possible to increase the efficacy of conventional cancer therapeutic strategies by targeting TAMs.

Animals↗
PubMed2005

Induction of a proinflammatory program in normal human thyrocytes by the RET/PTC1 oncogene.

Rearrangements of the RET receptor tyrosine kinase gene generating RET/PTC oncogenes are specific to papillary thyroid carcinoma (PTC), the most frequent thyroid tumor. Here, we show that the RET/PTC1 oncogene, when exogenously expressed in primary normal human thyrocytes, induces the expression of a large set of genes involved in inflammation and tumor invasion, including those encoding chemokines (CCL2, CCL20, CXCL8, and CXCL12), chemokine receptors (CXCR4), cytokines (IL1B, CSF-1, GM-CSF, and G-CSF), matrix-degrading enzymes (metalloproteases and urokinase-type plasminogen activator and its receptor), and adhesion molecules (L-selectin). This effect is strictly dependent on the presence of the RET/PTC1 Tyr-451 (corresponding to RET Tyr-1062 multidocking site). Selected relevant genes (CCL20, CCL2, CXCL8, CXCR4, L-selectin, GM-CSF, IL1B, MMP9, UPA, and SPP1/OPN) were found up-regulated also in clinical samples of PTC, particularly those characterized by RET/PTC activation, local extrathyroid spread, and lymph node metastases, when compared with normal thyroid tissue or follicular thyroid carcinoma. These results, demonstrating that the RET/PTC1 oncogene activates a proinflammatory program, provide a direct link between a transforming human oncogene, inflammation, and malignant behavior.

Blotting, Western↗
PubMed2005

The pattern recognition receptor PTX3 is recruited at the synapse between dying and dendritic cells, and edits the cross-presentation of self, viral, and tumor antigens.

Pentraxins are soluble pattern recognition receptors with a dual role: protection against extracellular microbes and autoimmunity. The mechanisms by which they accomplish these tasks are not yet fully understood. Here we show that the prototypic long pentraxin PTX3 is specifically recruited at both sides of the phagocytic synapse between dendritic cells (DCs) and dying cells and remains stably bound to the apoptotic membranes (estimated half-time > 36 hours). Apoptotic cells per se influence the production of PTX3 by maturing DCs. When both microbial stimuli and dying cells are present, PTX3 behaves as a flexible adaptor of DC function, regulating the maturation program and the secretion of soluble factors. Moreover a key event associated with autoimmunity (ie, the cross-presentation of epitopes expressed by apoptotic cells to T cells) abates in the presence of PTX3, as evaluated using self, viral, and tumor-associated model antigens (vinculin, NS3, and MelanA/MART1). In contrast, PTX3 did not influence the presentation of exogenous soluble antigens, an event required for immunity against extracellular pathogens. These data suggest that PTX3 acts as a third-party agent between microbial stimuli and dying cells, contributing to limit tissue damage under inflammatory conditions and the activation of autoreactive T cells.

3T3 Cells↗