Biomedical subjects

Alberto Mantovani

Publications and source records attributed to Alberto Mantovani.

At least 19 recordsLinked to original sources

PubMed2026

Multinucleated Giant Cells in Human Pancreatic Cancer Are a Distinct Macrophage Population Undergoing a DNA Damage Response and Associated with an Aggressive Tumor Microenvironment.

Macrophages (Mϕ) constitute a dominant and functionally diverse immune population within the microenvironment of pancreatic ductal adenocarcinoma (PDAC), yet how Mϕ heterogeneity contributes to the tumor remains poorly defined. In an institutional cohort of 145 PDAC specimens, we identified a population of multinucleated giant cells (MGC) of Mϕ origin, an entity previously described in chronic inflammation but rarely in cancer. CD68+ MGCs were present in 28% of tumors, enriched in squamous, nonglandular regions, and more frequent after neoadjuvant chemotherapy. By integrating spatial transcriptomics and quantitative imaging, we defined the features of these cells, which, compared with MGCs in nonneoplastic inflammatory lesions, lacked canonical polarization markers (HLA-DR and CD163) and displayed a distinctive transcriptional program characterized by upregulation of the POLR2K, TUBA8, COX5B, and VDAC1 genes, which encode proteins involved in DNA repair, oxidative stress, and MYC signaling. Spatial analyses revealed activation of hypoxia and extracellular matrix-remodeling pathways in MGC-associated niches, and experimental hypoxia promoted MGC formation in vitro. Consistent with these data, we found that in the The Cancer Genome Atlas (TCGA) Pancreatic Adenocarcinoma (PAAD) dataset a Mϕ MGC gene signature was enriched in the squamous PDAC subtype and correlated with poorer overall survival (P = 0.018). Morphometric and immunofluorescence analyses further showed increased 53BP1+Ki67+ nuclei and nuclear atypia in MGCs, indicating ongoing proliferation despite DNA damage. Together, these data identify MGCs of Mϕ origin as an immune cell state shaped by hypoxia and stress signaling, associated with aggressive tumor phenotypes, and potentially exploitable as an immune classifier in PDAC.

Humans↗

PubMed2007

New vistas on macrophage differentiation and activation.

Plasticity and heterogeneity are hallmarks of myelomonocytic differentiation and polarized activation. Evidence published in this issue of the European Journal of Immunology, together with other recent data, add new elements and perspectives to the current understanding of mononuclear phagocyte differentiation and activation and are discussed in this Commentary.

Animals↗

PubMed2006

p50 nuclear factor-kappaB overexpression in tumor-associated macrophages inhibits M1 inflammatory responses and antitumor resistance.

Tumor-associated macrophages (TAM) are a major inflammatory infiltrate in tumors and a major component of the protumor function of inflammation. TAM in established tumors generally have an M2 phenotype with defective production of interleukin-12 (IL-12) and high IL-10. Here, we report that defective responsiveness of TAM from a murine fibrosarcoma and human ovarian carcinoma to M1 activation signals was associated with a massive nuclear localization of the p50 nuclear factor-kappaB (NF-kappaB) inhibitory homodimer. p50 overexpression inhibited IL-12 expression in normal macrophages. TAM isolated from p50(-/-) mice showed normal production of M1 cytokines, associated with reduced growth of transplanted tumors. Bone marrow chimeras showed that p50 inactivation in hematopoietic cells was sufficient to result in reduced tumor growth. Thus, p50 NF-kappaB overexpression accounts for the inability of TAM to mount an effective M1 antitumor response capable of inhibiting tumor growth.

Active Transport, Cell Nucleus↗

PubMed2006

Vascular endothelium summary statement II: Cardiovascular disease prevention and control.

The prevention and control of cardiovascular disease (CVD), principally ischemic heart disease and stroke, are a major clinical and public health challenge. Worldwide, CVD accounts for substantial morbidity and mortality. The major modifiable CVD risk factors are known and all of them cause endothelial activation and dysfunction. Preventing and controlling the established risk factors are associated with preserved endothelial function and reduced risk of CVD. Research advances that improve our understanding of strategies to preserve endothelial function or make the endothelial cells resilient to environmental insults may help improve our preventive interventions. This summary statement addresses the current state of the science with respect to endothelial dysfunction and CVD pathogenesis, diagnostic evaluation, and suggested strategies for public health practice and research.

Animals↗

PubMed2006

Transcriptional profiling of the human monocyte-to-macrophage differentiation and polarization: new molecules and patterns of gene expression.

Comprehensive analysis of the gene expression profiles associated with human monocyte-to-macrophage differentiation and polarization toward M1 or M2 phenotypes led to the following main results: 1) M-CSF-driven monocyte-to-macrophage differentiation is associated with activation of cell cycle genes, substantiating the underestimated proliferation potential of monocytes. 2) M-CSF leads to expression of a substantial part of the M2 transcriptome, suggesting that under homeostatic conditions a default shift toward M2 occurs. 3) Modulation of genes involved in metabolic activities is a prominent feature of macrophage differentiation and polarization. 4) Lipid metabolism is a main category of modulated transcripts, with expected up-regulation of cyclo-oxygenase 2 in M1 cells and unexpected cyclo-oxygenase 1 up-regulation in M2 cells. 5) Each step is characterized by a different repertoire of G protein-coupled receptors, with five nucleotide receptors as novel M2-associated genes. 6) The chemokinome of polarized macrophages is profoundly diverse and new differentially expressed chemokines are reported. Thus, transcriptome profiling reveals novel molecules and signatures associated with human monocyte-to-macrophage differentiation and polarized activation which may represent candidate targets in pathophysiology.

Cell Differentiation↗

PubMed2006

Establishment of a high sensitivity plasma assay for human pentraxin3 as a marker for unstable angina pectoris.

OBJECTIVE: Plasma pentraxin 3 (PTX3) levels are increased in patients with acute myocardial infarction, yet its involvement in unstable angina pectoris (UAP) remains unclear. To critically evaluate the role of PTX3 in UAP, a sensitive and precise measurement of PTX3 concentration is needed. METHODS AND RESULTS: We established a high sensitive plasma ELISA assay system for the detection of PTX3 using monoclonal antibodies. The lower limit of detection of our ELISA was 0.1 ng/mL, sensitivity far greater than the current commercially available kit. Plasma samples were obtained from 162 consecutive patients treated for hypertension, hyperlipidemia, diabetes mellitus, or cardiovascular disease at a physician's office. PTX3 was not associated with any known coronary risk factors. Additionally, we collected plasma samples from 252 consecutive subjects admitted to a university hospital for coronary artery assessment by coronary angiography. PTX3 was significantly increased in patients in whom coronary intervention was performed. We further analyzed the plasma level of PTX3 in 52 patients with effort angina (EAP) and 16 patients with UAP. Compared with the control group, PTX3 were significantly higher in the UAP group. CONCLUSIONS: The levels of plasma PTX3 were increased in patients with arterial inflammation, especially UAP. This PTX3 detection system will be useful for the prediction of UAP.

Adult↗

PubMed2006

RalB signaling: a bridge between inflammation and cancer.

A connection between the genetic events that lead to tumor formation and the signaling pathways of the innate immune response has been established. In this issue, Chien et al. (2006) show that the RalB GTPase regulates the IKK family member TBK1, providing an unexpected link between the signaling pathways that promote inflammation and cancer. In tumor cells the RalB/TBK1 pathway inhibits apoptosis and in nontumorigenic cells it stimulates an innate immune response.

Cell Line, Tumor↗

PubMed2006

Differential effects of immunosuppressive drugs on chemokine receptor CCR7 in human monocyte-derived dendritic cells: selective upregulation by rapamycin.

BACKGROUND: Appropriate recruitment of dendritic cells (DC) at sites of inflammation and migration to secondary lymphoid organs is of critical importance for the initiation of Ag-specific immune responses. The proper localization of DC in selected tissues is guided primarily by the coordinated expression of chemokine receptors (CKR). Here we show that immunosuppressive drugs have divergent effects on the modulation of CKR in maturing DC. METHODS AND RESULTS: Dexamethazone (DEX) and IL-10 inhibited human DC migration to CCL19 in vitro and mouse DC migration to lymph nodes (LN) in vivo, by impairing CCR7 expression. The calcineurin inhibitors cyclosporine A (CsA) and tacrolimus (FK506) were characterized by the inability to modulate CKR expression and migratory activity. Rapamycin (RAPA) increased DC migration to CCL19 in vitro and to LN in vivo by enhancing CCR7 expression. This effect could be mediated, in LPS-maturing DC, by the inhibition of autocrine IL-10 production. The in vivo data obtained with ex vivo RAPA treated DC were confirmed in a model of in vivo drug administration in mice, suggesting a potential clinical relevance. CONCLUSIONS: These findings demonstrate that immunosuppressive agents differently modulate the CKR switch associated with maturing DC; in particular, RAPA selectively up-regulates CCR7 and enhances the migration of differentiated DC to regional LN. This study contributes to a better understanding of the role of immunosuppressive therapy on DC migration, a potentially relevant check point of immunosuppressive treatment.

Animals↗

PubMed2006

Structure and function of the long pentraxin PTX3 glycosidic moiety: fine-tuning of the interaction with C1q and complement activation.

The prototypic long pentraxin PTX3 is a unique fluid-phase pattern recognition receptor that plays a nonredundant role in innate immunity and female fertility. The PTX3 C-terminal domain is required for C1q recognition and complement activation and contains a single N-glycosylation site on Asn 220. In the present study, we characterized the structure of the human PTX3 glycosidic moiety and investigated its relevance in C1q interaction and activation of the complement classical pathway. By specific endo and exoglycosidases digestion and direct mass spectrometric analysis, we found that both recombinant and naturally occurring PTX3 were N-linked to fucosylated and sialylated complex-type sugars. Interestingly, glycans showed heterogeneity mainly in the relative amount of bi, tri, and tetrantennary structures depending on the cell type and inflammatory stimulus. Enzymatic removal of sialic acid or the entire glycosidic moiety equally enhanced PTX3 binding to C1q compared to that in the native protein, thus indicating that glycosylation substantially contributes to modulate PTX3/C1q interaction and that sialic acid is the main determinant of this contribution. BIAcore kinetic measurements returned decreasing K(off) values as sugars were removed, pointing to a stabilization of the PTX3/C1q complex. No major rearrangement of PTX3 quaternary structure was observed after desialylation or deglycosylation as established by size exclusion chromatography. Consistent with C1q binding, PTX3 desialylation enhanced the activation of the classical complement pathway, as assessed by C4 and C3 deposition. In conclusion, our results provided evidence of an involvement of the PTX3 sugar moiety in C1q recognition and complement activation.

Animals↗

PubMed2006

The long pentraxin PTX3 in vascular pathology.

Pentraxins are a family of evolutionarily conserved multifunctional pattern-recognition proteins characterized by a cyclic multimeric structure. Based on the primary structure of the subunit, the pentraxins are divided into two groups: short pentraxins and long pentraxins. C-reactive protein (CRP) and serum amyloid P-component (SAP) are the two short pentraxins. The prototype protein of the long pentraxin group is pentraxin 3 (PTX3). CRP and SAP are produced primarily in the liver in response to IL-6, while PTX3 is produced by a variety of tissues and cells and in particular by innate immunity cells in response to proinflammatory signals and Toll-like receptor (TLR) engagement. PTX3 interacts with several ligands, including growth factors, extracellular matrix components and selected pathogens, playing a role in complement activation and facilitating pathogen recognition by phagocytes, acting as a predecessor of antibodies. 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 non-redundant component of the humoral arm of innate immunity and involved in tuning inflammation, in matrix deposition and female fertility.

Animals↗

PubMed2006

Pentraxin 3 protects from MCMV infection and reactivation through TLR sensing pathways leading to IRF3 activation.

Reactivation of latent human cytomegalovirus (HCMV) following allogeneic transplantation is a major cause of morbidity and mortality and predisposes to severe complications, including superinfection by Aspergillus species (spp). Antimicrobial polypeptides, including defensins and mannan-binding lectin, are known to block viral fusion by cross-linking sugars on cell surface. Pentraxin 3 (PTX3), a member of the long pentraxin family, successfully restored antifungal immunity in experimental hematopoietic transplantation. We assessed here whether PTX3 binds HCMV and murine virus (MCMV) and the impact on viral infectivity and superinfection in vivo. We found that PTX3 bound both viruses, reduced viral entry and infectivity in vitro, and protected from MCMV primary infection and reactivation as well as Aspergillus superinfection. This occurred through the activation of interferon (IFN) regulatory factor 3 (IRF3) in dendritic cells via the TLR9/MyD88-independent viral recognition sensing and the promotion of the interleukin-12 (IL-12)/IFN-gamma-dependent effector pathway.

Animals↗

PubMed2006

Identification of an antiangiogenic FGF2-binding site in the N terminus of the soluble pattern recognition receptor PTX3.

Long-pentraxin 3 (PTX3) is a soluble pattern recognition receptor with non-redundant functions in inflammation and innate immunity. PTX3 comprises a pentraxin-like C-terminal domain involved in complement activation via C1q interaction and an N-terminal extension with unknown functions. PTX3 binds fibroblast growth factor-2 (FGF2), inhibiting its pro-angiogenic and pro-restenotic activity. Here, retroviral transduced endothelial cells (ECs) overexpressing the N-terminal fragment PTX3-(1-178) showed reduced mitogenic activity in response to FGF2. Accordingly, purified recombinant PTX3-(1-178) binds FGF2, prevents PTX3/FGF2 interaction, and inhibits FGF2 mitogenic activity in ECs. Also, the monoclonal antibody mAb-MNB4, which recognizes the PTX3-(87-99) epitope, prevents FGF2/PTX3 interaction and abolishes the FGF2 antagonist activity of PTX3. Consistently, the synthetic peptides PTX3-(82-110) and PTX3-(97-110) bind FGF2 and inhibit the interaction of FGF2 with PTX3 immobilized to a BIAcore sensor chip, FGF2-dependent EC proliferation, and angiogenesis in vivo. Thus, the data identify a FGF2-binding domain in the N-terminal extension of PTX3 spanning the PTX3-(97-110) region, pointing to a novel function for the N-terminal extension of PTX3 and underlining the complexity of the PTX3 molecule for modular humoral pattern recognition.

Amino Acid Sequence↗

PubMed2006

Differential regulation of chemokine production by Fcgamma receptor engagement in human monocytes: association of CCL1 with a distinct form of M2 monocyte activation (M2b, Type 2).

CC chemokine ligand 1 (CCL1; I-309) is a CC chemokine that interacts with CC chemokine receptor 8, which is preferentially expressed in polarized T helper cell type 2 and Tc2 cells, in eosinophils, and in T regulatory cells. The present study, prompted by transcriptional profiling of human monocytes undergoing different forms of activation, was designed to characterize the production of CCL1 in monocytes compared with the production of other chemokines (CCL2, CCL22, and CCL18) differentially regulated by distinct activation signals. Lipopolysaccharide (LPS), interferon-gamma (IFN-gamma), interleukin (IL)-1beta, tumor necrosis factor alpha, IL-4, IL-13, IL-10, IL-6, IL-18, and combinations thereof did not induce CCL1 production in monocytes, and some of these signals stimulated production of reference chemokines. Induction of CCL1 in monocytes required engagement of Fc receptor for immunoglobulin G (FcgammaR)II and exposure to IL-1beta or LPS. This combination of stimuli results in a form of M2 (M2b, Type 2) macrophage activation. FcgammaR engagement also induced CCL22 and amplified its stimulation by IL-4. In contrast, FcgammaR stimulation inhibited the IL-10- and LPS-mediated induction of CCL18. IL-10, IL-4, and IFN-gamma inhibited induction of CCL1 by FcgammaR ligation and IL-1beta. CCL1 was present in synovial fluids and macrophages in juvenile idiopathic arthritis. Thus, regulation of CCL1 in human monocytes is unique, with an obligate requirement of FcgammaR engagement and costimulation by signals (IL-1beta and LPS), which use the myeloid differentiation primary-response protein 88 adaptor protein. Thus, CCL1 is a CC chemokine with a unique pattern of regulation associated with a distinct form of M2 (Type 2, M2b) monocyte activation, which participates in macrophage-dependent regulatory circuits of innate and adaptive immunity.

Arthritis, Juvenile↗

PubMed2006

Efficient testing strategies for evaluation of xenobiotics with neuroendocrine activity.

Maturation of neuroendocrine regulations is an extremely complex process made up of several stages, that can be permanently affected by any exogenous substances able to interfere with the hormonal signalling at various levels. The Endocrine Disrupting Chemicals (EDCs) are a heterogeneous group of xenobiotics with potential endocrine activities which have been identified as priority risk factors in toxicological research. The present review is aimed at suggesting a number of endocrine and behavioural endpoints to be used in experimental studies to: (i) characterize more thoroughly the functional effects of developmental exposure to agents known to act as endocrine disruptors and (ii) unmask possible interferences with the maturation of the hypothalamus-hypophysis-gonad/thyroid (HHG/Th) axis by different class of xenobiotics not considered as EDCs. A combined testing strategy, considering both markers of endocrine/hormonal maturation and behavioural endpoints under hormonal control in laboratory rodents, may evidence even subtle perturbations of the neuroendocrine homeostasis, that often go undetected.

Animals↗

PubMed2006

Elevated maternal levels of the long pentraxin 3 (PTX3) in preeclampsia and intrauterine growth restriction.

OBJECTIVE: The prototypic long pentraxin pentraxin 3 is a new candidate marker for inflammatory conditions reflecting the involvement of the vascular bed. Endothelial dysfunction is a prominent feature of preeclampsia as a result of excessive maternal systemic inflammation. We investigated pentraxin 3 levels in preeclampsia and intrauterine growth restriction, pregnancy conditions related to altered placentation. STUDY DESIGN: We cross-sectionally studied nonpregnant women (n = 20); normal pregnancies in the first (n = 8), second (n = 10), and third (n = 26) trimester of pregnancy; 20 pregnancies complicated by preeclampsia; and 16 pregnancies complicated by intrauterine growth restriction. Maternal plasma samples were analyzed and pentraxin 3 determined by enzyme-linked immunosorbent assay. Pattern and site of placental expression of pentraxin 3 were studied by immunohistochemistry. RESULTS: In normal pregnancies pentraxin 3 concentrations were significantly higher than nonpregnant women and did not change among the 3 trimesters. Significantly higher levels of pentraxin 3 were found in preeclampsia (median values 13.8 versus 2.2 ng/mL; P < .001), compared with normal pregnancies. Intrauterine growth restriction pregnancies showed intermediate levels between normal and preeclamptic patients, but this difference was not significant, compared with normal pregnancies (median values 3.9 versus 2.2 ng/mL). No significant difference of pentraxin 3 levels was found between mild and severe preeclampsia. CONCLUSION: Elevated maternal plasma levels of pentraxin 3 in preeclamptic versus normal pregnancies could represent a marker of altered endothelial function, typical of preeclampsia.

Adult↗

PubMed2006

The tissue pentraxin PTX3 limits C1q-mediated complement activation and phagocytosis of apoptotic cells by dendritic cells.

Pentraxins (PTX) and complement belong to the humoral arm of the innate immune system and have essential functions in immune defense to microbes and in scavenging cellular debris. The prototypic long PTX, PTX3, and the first component of the classical complement pathway, C1q, are innate opsonins involved in the disposal of dying cells by phagocytes. Whether the interaction between various innate opsonins impacts on their function is not fully understood. We show here that characterized Toll-like receptor (TLR) ligands elicit the production of C1q and PTX3 by immature dendritic cells (DC). Moreover, these molecules bind to dying cells with similar kinetics, although they recognize different domains on the cell membranes. PTX3 binds in the fluid phase to C1q, decreasing C1q deposition and subsequent complement activation on apoptotic cells. C1q increases the phagocytosis of apoptotic cells by DC and the release of interleukin-12 in the presence of TLR4 ligands and apoptotic cells; PTX3 inhibits both events. Moreover, PTX3 inhibited the cross-presentation of the MELAN-A/melanoma antigen-reactive T cell 1 (MART-1) tumor antigen expressed by dying cells, even in the presence of C1q. These results suggest that interaction of C1q and PTX3 influences the clearance of apoptotic cells by DC. The coordinated induction by primary, proinflammatory signals of C1q and PTX3 and their reciprocal regulation during inflammation influences the clearance of apoptotic cells by antigen-presenting cells and possibly plays a role in immune homeostasis.

Antigen Presentation↗

PubMed2006

Interaction of C1q with IgG1, C-reactive protein and pentraxin 3: mutational studies using recombinant globular head modules of human C1q A, B, and C chains.

C1q is the first subcomponent of the classical complement pathway that can interact with a range of biochemically and structurally diverse self and nonself ligands. The globular domain of C1q (gC1q), which is the ligand-recognition domain, is a heterotrimeric structure composed of the C-terminal regions of A (ghA), B (ghB), and C (ghC) chains. The expression and functional characterization of ghA, ghB, and ghC modules have revealed that each chain has specific and differential binding properties toward C1q ligands. It is largely considered that C1q-ligand interactions are ionic in nature; however, the complementary ligand-binding sites on C1q and the mechanisms of interactions are still unclear. To identify the residues on the gC1q domain that are likely to be involved in ligand recognition, we have generated a number of substitution mutants of ghA, ghB, and ghC modules and examined their interactions with three selected ligands: IgG1, C-reactive protein (CRP), and pentraxin 3 (PTX3). Our results suggest that charged residues belonging to the apex of the gC1q heterotrimer (with participation of all three chains) as well as the side of the ghB are crucial for C1q binding to these ligands, and their contribution to each interaction is different. It is likely that a set of charged residues from the gC1q surface participate via different ionic and hydrogen bonds with corresponding residues from the ligand, instead of forming separate binding sites. Thus, a recently proposed model suggesting the rotation of the gC1q domain upon ligand recognition may be extended to C1q interaction with CRP and PTX3 in addition to IgG1.

Amino Acid Sequence↗

PubMed2006

Dual function of the long pentraxin PTX3 in resistance against pulmonary infection with Klebsiella pneumoniae in transgenic mice.

The long pentraxin PTX3 is expressed during acute inflammation and appears to control nitric oxide (NO) and tumor necrosis factor (TNF)-alpha production. In the present study, the physiological function of PTX3 was investigated in a model of pulmonary infection caused by the Gram-negative bacterium Klebsiella pneumoniae. Transgenic mice expressing multiple copies of PTX3 under the control of its own promoter were used to assess lethality rates, bacterial counts and inflammatory indices following pulmonary infection of mice. Expression of PTX3 is enhanced during pulmonary infection in wild-type mice. In transgenic mice given a high inoculum, overt PTX3 expression was associated with faster lethality. Faster lethality correlated with enhanced nitrate in plasma, an inability of neutrophils to migrate to lung tissue and greater dissemination of bacteria to blood at 20h after infection. In contrast, transgenic PTX3 expression conferred protection to mice given lower pulmonary inocula. In the latter experiments, there was enhanced TNF-alpha production, greater neutrophil influx and phagocytosis of bacteria by migrated neutrophils. By controlling the production of TNF-alpha and NO, and depending on the intensity of the inflammatory response induced by a given inoculum, the expression of PTX3 may favor or disfavor the influx of neutrophils and the ability of the murine host to deal with pulmonary infection with K. pneumoniae. These experiments highlight the delicate balance that exists among the various mediators that control the inflammatory response and suggest that PTX3 is an essential part of the ability of a host to deal with bacterial infection.

Animals↗