Other articles by Elisa Romeo on PubMed

• CD59 is Physically and Functionally Associated with Natural Cytotoxicity Receptors and Activates Human NK Cell-mediated Cytotoxicity European Journal of Immunology. Dec, 2003  |   Pubmed ID: 14635045 Triggering of cytotoxicity in human NK cells is induced by the combined engagement of several triggering receptors. These include primary receptors such as NKG2D and the natural cytotoxicity receptors (NCR) NKp30, NKp46 and NKp44, while other molecules, including 2B4, NTB-A and NKp80, function as co-receptors. As reported in the present study, during an attempt to identify novel NK receptors or co-receptors, we found that CD59 functions as a co-receptor in human NK cell activation; engagement of CD59 by specific mAb delivers triggering signals to human NK cells, resulting in enhancement of cytotoxicity. Similar to other NK co-receptors, the triggering function of CD59, a glycosylphosphatidylinositol (GPI)-linked protein, depends on the simultaneous engagement of primary receptors such as NCR. Accordingly, CD59-dependent triggering was virtually restricted to NK cells expressing high surface densities of NKp46, and mAb-mediated modulation of NKp46 resulted in markedly decreased responses to anti-CD59 mAb. Biochemical analysis revealed that CD59 is physically associated with NKp46 and NKp30. Moreover, engagement of CD59 resulted in tyrosine phosphorylation of CD3zeta chains associated with these NCR, but not those associated with CD16. Thus, CD59-mediated costimulation of NK cells requires direct physical interaction of this GPI-linked protein with primary triggering NK receptors.
• Proximal Renal Tubular Acidosis in TASK2 K+ Channel-deficient Mice Reveals a Mechanism for Stabilizing Bicarbonate Transport Proceedings of the National Academy of Sciences of the United States of America. May, 2004  |   Pubmed ID: 15141089 The acid- and volume-sensitive TASK2 K+ channel is strongly expressed in renal proximal tubules and papillary collecting ducts. This study was aimed at investigating the role of TASK2 in renal bicarbonate reabsorption by using the task2 -/- mouse as a model. After backcross to C57BL6, task2 -/- mice showed an increased perinatal mortality and, in adulthood, a reduced body weight and arterial blood pressure. Patch-clamp experiments on proximal tubular cells indicated that TASK2 was activated during HCO3- transport. In control inulin clearance measurements, task2 -/- mice showed normal NaCl and water excretion. During i.v. NaHCO3 perfusion, however, renal Na+ and water reabsorption capacity was reduced in -/- animals. In conscious task2 -/- mice, blood pH, HCO3- concentration, and systemic base excess were reduced but urinary pH and HCO3- were increased. These data suggest that task2 -/- mice exhibit metabolic acidosis caused by renal loss of HCO3-. Both in vitro and in vivo results demonstrate the specific coupling of TASK2 activity to HCO3- transport through external alkalinization. The consequences of the task2 gene inactivation in mice are reminiscent of the clinical manifestations seen in human proximal renal tubular acidosis syndrome.
• Homophilic Interaction of NTBA, a Member of the CD2 Molecular Family: Induction of Cytotoxicity and Cytokine Release in Human NK Cells European Journal of Immunology. Jun, 2004  |   Pubmed ID: 15162436 NK-T-B antigen (NTBA) is a CD2 family member that functions as a coreceptor in human NK cell activation. Several receptor/ligand interactions occur between different members of this molecular family. In this study, in order to identify the natural ligand of NTBA, we produced a chimeric protein formed by the NTBA extracellular region fused with the Fc portion of human IgG1 (termed NTBA-Fc*). NTBA-Fc* specifically binds to NTBA cell transfectants but not to cells transfected with other CD2 family members including CD2, CD48, CD84, CD150, CD229, and CD244. Moreover, NTBA-Fc* also binds to NTBA(+) but not to NTBA(-) T cell lines. Enzyme-linked immunosorbent assays, plasmon resonance analysis, as well as NTBA-Fc*-mediated down-regulation of NTBA surface expression further confirmed the occurrence of NTBA/NTBA homophilic interaction. Functionally, in NK cells, NTBA-Fc* promoted a strong production of IFN-gamma and TNF-alpha. Moreover, NTBA-transfected targets displayed increased susceptibility to NK-mediated killing as compared to untransfected cells and this effect was specifically inhibited by anti-NTBA mAb. Altogether our data indicate that NTBA is characterized by self recognition.
• Mutations in SLC6A19, Encoding B0AT1, Cause Hartnup Disorder Nature Genetics. Sep, 2004  |   Pubmed ID: 15286787 Hartnup disorder, an autosomal recessive defect named after an English family described in 1956 (ref. 1), results from impaired transport of neutral amino acids across epithelial cells in renal proximal tubules and intestinal mucosa. Symptoms include transient manifestations of pellagra (rashes), cerebellar ataxia and psychosis. Using homozygosity mapping in the original family in whom Hartnup disorder was discovered, we confirmed that the critical region for one causative gene was located on chromosome 5p15 (ref. 3). This region is homologous to the area of mouse chromosome 13 that encodes the sodium-dependent amino acid transporter B(0)AT1 (ref. 4). We isolated the human homolog of B(0)AT1, called SLC6A19, and determined its size and molecular organization. We then identified mutations in SLC6A19 in members of the original family in whom Hartnup disorder was discovered and of three Japanese families. The protein product of SLC6A19, the Hartnup transporter, is expressed primarily in intestine and renal proximal tubule and functions as a neutral amino acid transporter.
• Isolation of a Novel KIR2DL3-specific MAb: Comparative Analysis of the Surface Distribution and Function of KIR2DL2, KIR2DL3 and KIR2DS2 International Immunology. Oct, 2004  |   Pubmed ID: 15314042 In recent years an increasing number of sequences coding for new KIRs have been described. However, the limited availability of mAbs with unique KIR specificities has hindered an exhaustive assessment of their actual function, HLA-specificity, expression at the cell surface and distribution in different cell populations. In this study we report the generation of a novel mAb (ECM41) specific for KIR2DL3 molecules. By the use of cell transfectants expressing one or other KIR we show that this reagent allows discrimination of KIR2DL3 from other GL183 mAb-reactive molecules such as KIR2DL2 and KIR2DS2. Moreover we show that this novel mAb can be used to assess the surface expression and distribution of KIR2DL3 in different polyclonal NK populations and in NK cell clones. Along this line, we were able to analyze the HLA class I specificity of NK clones expressing either KIR2DL3 or KIR2DL2, two inhibitory receptors that were so far serologically undistinguishable. Finally, the combined use of GL183 and ECM41 mAbs in redirected killing assays allowed us to investigate the functional outcome of the simultaneous engagement of KIR2DL3 and KIR2DS2 in NK cell clones co-expressing KIRs that display opposite (inhibitory vs activating) function.
• Heteromeric KCNE2/KCNQ1 Potassium Channels in the Luminal Membrane of Gastric Parietal Cells The Journal of Physiology. Dec, 2004  |   Pubmed ID: 15579540 Recently, we and others have shown that luminal K+ recycling via KCNQ1 K+ channels is required for gastric H+ secretion. Inhibition of KCNQ1 by the chromanol 293B strongly diminished H+ secretion. The present study aims at clarifying KCNQ1 subunit composition, subcellular localization, regulation and pharmacology in parietal cells. Using in situ hybridization and immunofluorescence techniques, we identified KCNE2 as the beta subunit of KCNQ1 in the luminal membrane compartment of parietal cells. Expressed in COS cells, hKCNE2/hKCNQ1 channels were activated by acidic pH, PIP2, cAMP and purinergic receptor stimulation. Qualitatively similar results were obtained in mouse parietal cells. Confocal microscopy revealed stimulation-induced translocation of H+,K+-ATPase from tubulovesicles towards the luminal pole of parietal cells, whereas distribution of KCNQ1 K+ channels did not change to the same extent. In COS cells the 293B-related substance IKs124 blocked hKCNE2/hKCNQ1 with an IC50 of 8 nM. Inhibition of hKCNE1- and hKCNE3-containing channels was weaker with IC50 values of 370 and 440 nM, respectively. In conclusion, KCNQ1 coassembles with KCNE2 to form acid-activated luminal K+ channels of parietal cells. KCNQ1/KCNE2 is activated during acid secretion via several pathways but probably not by targeting of the channel to the membrane. IKs124 could serve as a leading compound in the development of subunit-specific KCNE2/KCNQ1 blockers to treat peptic ulcers.
• Novel Renal Amino Acid Transporters Annual Review of Physiology. 2005  |   Pubmed ID: 15709970 Reabsorption of amino acids, similar to that of glucose, is a major task of the proximal kidney tubule. Various amino acids are actively transported across the luminal brush border membrane into proximal tubule epithelial cells, most of which by cotransport. An important player is the newly identified cotransporter (symporter) B0AT1 (SLC6A19), which imports a broad range of neutral amino acids together with Na+ across the luminal membrane and which is defective in Hartnup disorder. In contrast, cationic amino acids and cystine are taken up in exchange for recycled neutral amino acids by the heterodimeric cystinuria transporter. The basolateral release of some neutral amino acids into the extracellular space is mediated by unidirectional efflux transporters, analogous to GLUT2, that have not yet been definitively identified. Additionally, cationic amino acids and some other neutral amino acids leave the cell basolaterally via heterodimeric obligatory exchangers.
• Luminal Kidney and Intestine SLC6 Amino Acid Transporters of B0AT-cluster and Their Tissue Distribution in Mus Musculus American Journal of Physiology. Renal Physiology. Feb, 2006  |   Pubmed ID: 16174864 The B degrees transport system mediates the Na(+)-driven uptake of a broad range of neutral amino acids into epithelial cells of small intestine and kidney proximal tubule. A corresponding transporter was identified in 2004 (A. Broer, K. Klingel, S. Kowalczuk, J. E. Rasko, J. Cavanaugh, and S. Broer. J Biol Chem 279: 24467-24476, 2004) within the SLC6 family and named B degrees AT1 (SLC6A19). A phylogenetically related transporter known as XT3 in human (SLC6A20) and XT3s1 in mouse was shown to function as an imino acid transporter, to localize also to kidney and small intestine and renamed SIT1 or Imino(B). Besides these two transporters with known functions, there are two other gene products belonging to the same phylogenetic B degrees AT-cluster, XT2 (SLC6A18) and rodent XT3 that are still "orphans." Quantitative real-time RT-PCR showed that the mRNAs of the four B degrees AT-cluster members are abundant in kidney, whereas only those of B degrees AT1 and XT3s1/SIT1 are elevated in small intestine. In brain, the XT3s1/SIT1 mRNA is more abundant than the other B degrees AT-cluster mRNAs. We show here by immunofluorescence that all four mouse B degrees AT-cluster transporters localize, with differential axial gradients, to the brush-border membrane of proximal kidney tubule and, with the possible exception of XT3, also of intestine. Deglycosylation and Western blotting of brush-border proteins demonstrated the glycosylation and confirmed the luminal localization of B degrees AT1, XT2, and XT3. In summary, this study shows the luminal brush-border localization of the Na(+)-dependent amino and imino acid transporters B degrees AT1 and XT3s1/SIT1 in kidney and intestine. It also shows that the structurally highly similar orphan transporters XT2 and XT3 have the same luminal but a slightly differing axial localization along the kidney proximal tubule.
• Neutral Amino Acid Transport Mediated by Ortholog of Imino Acid Transporter SIT1/SLC6A20 in Opossum Kidney Cells American Journal of Physiology. Renal Physiology. Apr, 2006  |   Pubmed ID: 16234310 Most neutral l-amino acid acids are transported actively across the luminal brush-border membrane of small intestine and kidney proximal tubule epithelial cells by a Na(+) cotransport system named B(0) that has been recently molecularly identified (B(0)AT1, SLC6A19). We show here that the opossum kidney-derived cell line OK also displays a Na(+)-dependent B(0)-type neutral l-amino acid transport, although with a slightly differing substrate selectivity. We tested the hypothesis that one of the two B(0)AT1-related transporters, SLC6A18 (ortholog of orphan transporter XT2) or SLC6A20 (ortholog of the recently identified mammalian imino acid transporter SIT1), mediates this transport. Anti-sense RNA to OK SIT1 (oSIT1) but not to OK XT2 (oXT2) inhibited Na(+)-dependent neutral amino acid transport induced by OK mRNA injected in Xenopus laevis oocytes. Furthermore, inhibition of oSIT1 gene expression in OK cells by transfection of siRNA and expression of shRNA selectively reduced the Na(+)-dependent uptake of neutral l-amino acids. Finally, expression of OK cell oSIT1 cRNA in X. laevis oocytes induced besides the transport of the l-imino acid l-Pro also that of neutral l-amino acids. Taken together, the data indicate that in OK cells SIT1 (SLC6A20) is not only an apical imino acid transporter but also plays a major role as Na(+)-dependent neutral l-amino acid transporter. A similar double role could be envisaged for SIT1 in mammalian kidney proximal tubule and small intestine.
• Shunt-associated Migraines Respond Favorably to Changes in Work Conditions Stroke; a Journal of Cerebral Circulation. Jun, 2006  |   Pubmed ID: 16645129
• Analysis of Natural Killer Cells Isolated from Human Decidua: Evidence That 2B4 (CD244) Functions As an Inhibitory Receptor and Blocks NK-cell Function Blood. Dec, 2006  |   Pubmed ID: 16931625 While during the first trimester of pregnancy natural killer (NK) cells represent the most abundant lymphocyte population in the decidua, their actual function at this site is still debated. In this study we analyzed NK cells isolated from decidual tissue for their surface phenotype and functional capability. We show that decidual NK (dNK) cells express normal surface levels of certain activating receptors, including NKp46, NKG2D, and 2B4, as well as of killer cell immunoglobulin-like receptors (KIRs) and CD94/NKG2A inhibitory receptor. In addition, they are characterized by high levels of cytoplasmic granules despite their CD56(bright) CD16- surface phenotype. Moreover, we provide evidence that in dNK cells, activating NK receptors display normal triggering capability whereas 2B4 functions as an inhibitory receptor. Thus, cross-linking of 2B4 resulted in inhibition of both cytolytic activity and interferon-gamma (IFN-gamma) production. Clonal analysis revealed that, in the majority of dNK cell clones, the 2B4 inhibitory function is related to the deficient expression of signaling lymphocyte activation molecule (SLAM)-associated protein (SAP) mRNA. Moreover, biochemical analysis revealed low levels of SAP in the dNK polyclonal population. This might suggest that dNK cells, although potentially capable of killing, are inhibited in their function when interacting with cells expressing CD48.
• [PM 10 Exposure and Asthma Exacerbations in Pediatric Age: a Meta-analysis of Panel and Time-series Studies] Epidemiologia E Prevenzione. Jul-Oct, 2006  |   Pubmed ID: 17176939 review of the time series and panel studies on the short term effects of PM10 on the increases of the illness in childhood.
• COX-2 Suppresses Tissue Factor Expression Via Endocannabinoid-directed PPARdelta Activation The Journal of Experimental Medicine. Sep, 2007  |   Pubmed ID: 17724132 Although cyclooxygenase (COX)-2 inhibitors (coxibs) are effective in controlling inflammation, pain, and tumorigenesis, their use is limited by the recent revelation of increased adverse cardiovascular events. The mechanistic basis of this side effect is not well understood. We show that the metabolism of endocannabinoids by the endothelial cell COX-2 coupled to the prostacyclin (PGI(2)) synthase (PGIS) activates the nuclear receptor peroxisomal proliferator-activated receptor (PPAR) delta, which negatively regulates the expression of tissue factor (TF), the primary initiator of blood coagulation. Coxibs suppress PPARdelta activity and induce TF expression in vascular endothelium and elevate circulating TF activity in vivo. Importantly, PPARdelta agonists suppress coxib-induced TF expression and decrease circulating TF activity. We provide evidence that COX-2-dependent attenuation of TF expression is abrogated by coxibs, which may explain the prothrombotic side-effects for this class of drugs. Furthermore, PPARdelta agonists may be used therapeutically to suppress coxib-induced cardiovascular side effects.
• Heterogeneity of TLR3 MRNA Transcripts and Responsiveness to Poly (I:C) in Human NK Cells Derived from Different Donors International Immunology. Dec, 2007  |   Pubmed ID: 17962643 TLR3 plays an important role in the activation of different cell types of the innate immune system. Previous studies indicated that human NK cells express TLR3 and that, upon stimulation by polyinosinic-polycytidylic acid [poly (I:C)], they release cytokines and up-regulate cytotoxicity. Here we show that NK cells display heterogeneous levels of TLR3 mRNA transcript. Analysis of NK cell clones did not reveal significant correlation between the levels of TLR3 mRNA transcripts and the expression of different surface NK receptors including killer Ig-like receptor and NKG2A. On the other hand, the level of TLR3 mRNA transcript detected in given clones correlated with the ability of these clones to respond to poly (I:C). Thus, clones displaying higher TLR3 mRNA transcripts were characterized by higher cytokine production and cytotoxicity. Moreover, the increased cytolytic activity induced by treatment with poly (I:C) does not depend on increment of the expression of activating NK receptors and co-receptors, adhesion molecules or perforin/granzyme, but correlates with higher cell responsiveness to NKp46 ligation. Remarkably, in the presence of poly (I:C), even NKp46(dull) NK cell clones become cytolytic when characterized by high levels of TLR3 transcript. Thus, our present study provides an useful tool for both a quantitative and qualitative analysis of TLR3 in NK cells and contributes to explain the heterogeneous responsiveness to poly (I:C) of NK cells derived from different individuals.
• Evidence That the KIR2DS5 Gene Codes for a Surface Receptor Triggering Natural Killer Cell Function European Journal of Immunology. Aug, 2008  |   Pubmed ID: 18624290 In this study, after immunization with NK cells from a KIR2DS5(+) donor and screening on cell transfectants expressing different members of the killer immunoglobulin-like receptor (KIR) family, we generated a mAb, DF200, reacting with several KIR2D receptors including KIR2DL1/L2/L3, KIR2DS1/S2 and KIR2DS5. By the analysis of peripheral blood NK cells and in vitro derived NK cell clones, we have demonstrated for the first time that KIR2DS5 is expressed at the cell surface in discrete subsets of NK cells and, after DF200 mAb-mediated engagement, can induce both cytotoxicity and cytokine release. Using co-transfection and co-immunoprecipitation, we found that KIR2DS5 associates with the DAP12 signaling polypeptide. Finally, soluble KIR2DS5-Fc fusion protein does not bind to cell transfectants expressing different HLA-C alleles, suggesting that, if KIR2DS5 does recognize HLA-C molecules, this may only occur in the presence of certain peptides.
• Anti-leukemia Activity of Alloreactive NK Cells in KIR Ligand-mismatched Haploidentical HSCT for Pediatric Patients: Evaluation of the Functional Role of Activating KIR and Redefinition of Inhibitory KIR Specificity Blood. Mar, 2009  |   Pubmed ID: 18945967 We analyzed 21 children with leukemia receiving haploidentical hematopoietic stem cell transplantation (haplo-HSCT) from killer immunoglobulin (Ig)-like receptors (KIR) ligand-mismatched donors. We showed that, in most transplantation patients, variable proportions of donor-derived alloreactive natural killer (NK) cells displaying anti-leukemia activity were generated and maintained even late after transplantation. This was assessed through analysis of donor KIR genotype, as well as through phenotypic and functional analyses of NK cells, both at the polyclonal and clonal level. Donor-derived KIR2DL1(+) NK cells isolated from the recipient displayed the expected capability of selectively killing C1/C1 target cells, including patient leukemia blasts. Differently, KIR2DL2/3(+) NK cells displayed poor alloreactivity against leukemia cells carrying human leukocyte antigen (HLA) alleles belonging to C2 group. Unexpectedly, this was due to recognition of C2 by KIR2DL2/3, as revealed by receptor blocking experiments and by binding assays of soluble KIR to HLA-C transfectants. Remarkably, however, C2/C2 leukemia blasts were killed by KIR2DL2/3(+) (or by NKG2A(+)) NK cells that coexpressed KIR2DS1. This could be explained by the ability of KIR2DS1 to directly recognize C2 on leukemia cells. A role of the KIR2DS2 activating receptor in leukemia cell lysis could not be demonstrated. Altogether, these results may have important clinical implications for the selection of optimal donors for haplo-HSCT.
• Orphan Transporter SLC6A18 is Renal Neutral Amino Acid Transporter B0AT3 The Journal of Biological Chemistry. Jul, 2009  |   Pubmed ID: 19478081 The orphan transporter Slc6a18 (XT2) is highly expressed at the luminal membrane of kidney proximal tubules and displays approximately 50% identity with Slc6a19 (B(0)AT1), which is the main neutral amino acid transporter in both kidney and small intestine. As yet, the amino acid transport function of XT2 has only been experimentally supported by the urinary glycine loss observed in xt2 null mice. We report here that in Xenopus laevis oocytes, co-expressed ACE2 (angiotensin-converting enzyme 2) associates with XT2 and reveals its function as a Na(+)- and Cl(-)-de pend ent neutral amino acid transporter. In contrast to its association with ACE2 observed in Xenopus laevis oocytes, our experiments with ace2 and collectrin null mice demonstrate that in vivo it is Collectrin, a smaller homologue of ACE2, that is required for functional expression of XT2 in kidney. To assess the function of XT2 in vivo, we reanalyzed its knock-out mouse model after more than 10 generations of backcrossing into C57BL/6 background. In addition to the previously published glycinuria, we observed a urinary loss of several other amino acids, in particular beta-branched and small neutral ones. Using telemetry, we confirmed the previously described link of XT2 absence with hypertension but only in physically restrained animals. Taken together, our data indicate that the formerly orphan transporter XT2 functions as a sodium and chloride-de pend ent neutral amino acid transporter that we propose to rename B(0)AT3.
• GPR56 As a Novel Marker Identifying the CD56dull CD16+ NK Cell Subset Both in Blood Stream and in Inflamed Peripheral Tissues International Immunology. Feb, 2010  |   Pubmed ID: 20008459 To define novel human NK cell markers, we generated two mAbs specific for G-protein-coupled receptor 56 (GPR56), a surface glycoprotein that appears to be involved in cell-to-cell and cell-to-matrix interactions. GPR56 has been described in selected normal tissues, and in certain tumors, while, as yet, its expression on leukocytes is unknown. In this study, we show that anti-GPR56 mAbs, among leukocytes, prevalently recognize NK cells. In particular, these mAbs brightly stain CD56(dull) CD16(+) NK cells while react poorly with CD56(bright) CD16(+/-) NK cells. Consistently, we found that GPR56 was expressed on NK cells populating inflamed peripheral tissues while it was absent in lymph node-derived NK cells. We also show that activating stimuli, such as cytokines or exposure to monocyte-derived dendritic cell, down-regulate NK cell expression of GPR56 both at the protein and at the transcriptional level. Interestingly, IL-18, known to induce de novo expression of CCR7 on CD56(dull) CD16(+) NK cells, displayed the highest capability of modulating GPR56. Thus, together with the identification of GPR56 as a novel marker capable of discriminating different NK cells subsets, our data suggest that GPR56 may take part to the mechanisms regulating NK cell migration through the blood stream, peripheral tissues and lymph nodes.
• Short-term Effects of PM10 and NO2 on Respiratory Health Among Children with Asthma or Asthma-like Symptoms: a Systematic Review and Meta-analysis Environmental Health Perspectives. Apr, 2010  |   Pubmed ID: 20064785 Our goal was to quantify the short-term effects of particulate matter with aerodynamic diameter < or = 10 microm (PM10) and nitrogen dioxide (NO2) on respiratory health of asthmatic children from published panel studies, and to investigate the influence of study and population characteristics as effect modifiers.
• A Novel KIR-associated Function: Evidence That CpG DNA Uptake and Shuttling to Early Endosomes is Mediated by KIR3DL2 Blood. Sep, 2010  |   Pubmed ID: 20147700 Human natural killer (NK) cells express Toll-like receptor 9 (TLR9) transcript and, upon exposure to microbial CpG oligodeoxynucleotide (ODN), release cytokines and kill target cells. Here we show that NK cell treatment with CpG ODN results in down-modulation of KIR3DL2 inhibitory receptor from the cell surface and in its cointernalization with CpG ODN. CpG ODN-induced interferon-γ (IFN-γ) release is mostly confined to KIR3DL2(+) NK cells, thus suggesting a crucial role of KIR3DL2 in CpG ODN-mediated NK responses. Using soluble receptor molecules, we demonstrate the direct binding of KIR3DL2 to ODNs and we show that the D0 domain is involved primarily in this interaction. KIR3DL2 modulation is also induced in malignant cells of Sézary cutaneous T-cell lymphoma, a disease in which KIR3DL2 represents a typical marker of malignant T cells. Confocal microscopy analysis suggests that, in human NK cells, CpG ODN can encounter TLR9 in early endosomes after being shuttled to these sites by KIR3DL2, which functions as a CpG ODN receptor at the cell surface. This novel KIR-associated function emphasizes the antimicrobial role of NK cells in the course of infection.
• Combined Genotypic and Phenotypic Killer Cell Ig-like Receptor Analyses Reveal KIR2DL3 Alleles Displaying Unexpected Monoclonal Antibody Reactivity: Identification of the Amino Acid Residues Critical for Staining Journal of Immunology (Baltimore, Md. : 1950). Jul, 2010  |   Pubmed ID: 20525888 In humans, recent clinical and experimental data from hematopoietic stem cell transplantation revealed that donor-derived alloreactive NK cells exert a beneficial graft versus leukemia effect. The existence of donor-derived alloreactive NK cells can be predicted on the basis of donor killer cell Ig-like receptor (KIR) gene profile and HLA class I typing of both donor and recipient. Moreover, the size of the alloreactive NK cell population can be directly assessed by the combined use of anti-KIR-specific mAb. In this study, in an attempt to improve the definition of alloreactive NK cell subsets, we assessed the KIR genotype and phenotype in a cohort of 44 donors. This approach allowed the identification of two different KIR2DL3 alleles (KIR2DL3*005 and the novel allele KIR2DL3*015) that did not react with the anti-KIR2DL3-specific ECM41 mAb. In contrast, both alleles were recognized at the cell surface by several mAb reacting with KIR2DL2/L3/S2. Notably, KIR2DL3*005 was also stained by the anti-KIR2DL1/S1-specific EB6B and 11PB6 mAb. Functional analysis revealed that, despite its particular mAb reactivity, the specificity of KIR2DL3*005 for HLA-C molecules did not differ from that of other KIR2DL2/L3 alleles. Finally, site-directed mutagenesis demonstrated that glutamine at position 35 is required for ECM41 staining, whereas glutamic acid 35 and arginine 50 are relevant for staining with EB6B or 11PB6 mAb. Our present data represent a substantial progress in the characterization of the NK cell repertoire and an improved phenotypic/functional definition of given KIR(+) subsets.
• Natural Killer Cells Expressing the KIR2DS1-activating Receptor Efficiently Kill T-cell Blasts and Dendritic Cells: Implications in Haploidentical HSCT Blood. Apr, 2011  |   Pubmed ID: 21355085 In allogeneic HSCT, NK-cell alloreactivity is determined by the presence in the donor of NK cells expressing inhibitory killer cell Ig-like receptors (KIRs) that recognize HLA class I allotypes present in the donor but lacking in the recipient. Dominant KIR ligands are the C1 and C2 epitopes of HLA-C. All HLA-C allotypes have either the C1 epitope, the ligand for KIR2DL2/L3, or the C2 epitope, the ligand for KIR2DL1/S1. Here, we show that, in alloreactive NK-cell responses, KIR2DS1 expression represents a remarkable advantage as it allows efficient killing of C2/C2 or C1/C2 myelomonocitic dendritic cells (DCs) and T-cell blasts. When DCs or T-cell blasts were derived from C2/C2, Bw4/Bw4 donors, the activating signals delivered by KIR2DS1 could override the inhibition generated by NKG2A or KIR2DL2/L3 expressed on the same NK-cell clone. Furthermore, substantial lysis of C2/C2, Bw4/Bw6 targets was mediated by KIR2DS1(+) NK cells coexpressing KIR3DL1. Importantly, in the case of C1/C2 targets, KIR2DS1(+) NK cells were inhibited by the coexpression of KIR2DL2/L3 but not of NKG2A. Thus, KIR2DS1 expression in HSC donors may substantially increase the size of the alloreactive NK-cell subset leading to an enhanced ability to limit GVHD and improve engrafment.
• Breast Cancer Misclassification: a Major Obstacle to Treatment? Women's Health (London, England). Nov, 2011  |   Pubmed ID: 22040201
• Pleural Malignant Mesothelioma Epidemic: Incidence, Modalities of Asbestos Exposure and Occupations Involved from the Italian National Register International Journal of Cancer. May, 2012  |   Pubmed ID: 21647880 Due to the large scale use of asbestos (more than 3.5 million tons produced or imported until its definitive banning in 1992), a specific national surveillance system of mesothelioma incident cases is active in Italy, with direct and individual anamnestic etiological investigation. In the period between 1993 and 2004, a case-list of 8,868 pleural MM was recorded by the Italian National Register (ReNaM) and the modalities of exposure to asbestos fibres have been investigated for 6,603 of them. Standardized incidence rates are 3.49 (per 100,000 inhabitants) for men and 1.25 for women, with a wide regional variability. Occupational asbestos exposure was in 69.3% of interviewed subjects (N = 4,577 cases), while 4.4% was due to cohabitation with someone (generally, the husband) occupationally exposed, 4.7% by environmental exposure from living near a contamination source and 1.6% during a leisure activity. In the male group, 81.5% of interviewed subjects exhibit an occupational exposure. In the exposed workers, the median year of first exposure was 1957, and mean latency was 43.7 years. The analysis of exposures by industrial sector focuses on a decreasing trend for those traditionally signaled as "at risk" (asbestos-cement industry, shipbuilding and repair and railway carriages maintenance) and an increasing trend for the building construction sector. The systematic mesothelioma surveillance system is relevant for the prevention of the disease and for supporting an efficient compensation system. The existing experience on all-too-predictable asbestos effects should be transferred to developing countries where asbestos use is spreading.
• β-Lactones Inhibit N-acylethanolamine Acid Amidase by S-Acylation of the Catalytic N-Terminal Cysteine ACS Medicinal Chemistry Letters. May, 2012  |   Pubmed ID: 24900487 The cysteine amidase N-acylethanolamine acid amidase (NAAA) is a member of the N-terminal nucleophile class of enzymes and a potential target for anti-inflammatory drugs. We investigated the mechanism of inhibition of human NAAA by substituted β-lactones. We characterized pharmacologically a representative member of this class, ARN077, and showed, using high-resolution liquid chromatography-tandem mass spectrometry, that this compound forms a thioester bond with the N-terminal catalytic cysteine in human NAAA.
• A Binding Site for Nonsteroidal Anti-inflammatory Drugs in Fatty Acid Amide Hydrolase Journal of the American Chemical Society. Jan, 2013  |   Pubmed ID: 23240907 In addition to inhibiting the cyclooxygenase (COX)-mediated biosynthesis of prostanoids, various widely used nonsteroidal anti-inflammatory drugs (NSAIDs) enhance endocannabinoid signaling by blocking the anandamide-degrading membrane enzyme fatty acid amide hydrolase (FAAH). The X-ray structure of FAAH in complex with the NSAID carprofen, along with site-directed mutagenesis, enzyme activity assays, and NMR analysis, has revealed the molecular details of this interaction, providing information that may guide the design of dual FAAH-COX inhibitors with superior analgesic efficacy.
• [Occupational Exposure to Asbestos and Incidence of Malignant Mesothelioma in the Lazio Region, Years 2001-2009: Results of the Activities of the Regional Register] La Medicina Del Lavoro. Mar-Apr, 2013  |   Pubmed ID: 23789518 The Lazio Regional Mesothelioma Registry records the incident cases of Malignant Mesothelioma (MM) in residents in the Region since 2001.
• Development of Fragment-based N-FABS NMR Screening Applied to the Membrane Enzyme FAAH Chembiochem : a European Journal of Chemical Biology. Sep, 2013  |   Pubmed ID: 23918626 Despite the recognized importance of membrane proteins as pharmaceutical targets, the reliable identification of fragment hits that are able to bind these proteins is still a major challenge. Among different ¹⁹F NMR spectroscopic methods, n-fluorine atoms for biochemical screening (n-FABS) is a highly sensitive technique that has been used efficiently for fragment screening, but its application for membrane enzymes has not been reported yet. Herein, we present the first successful application of n-FABS to the discovery of novel fragment hits, targeting the membrane-bound enzyme fatty acid amide hydrolase (FAAH), using a library of fluorinated fragments generated based on the different local environment of fluorine concept. The use of the recombinant fusion protein MBP-FAAH and the design of compound 11 as a suitable novel fluorinated substrate analogue allowed n-FABS screening to be efficiently performed using a very small amount of enzyme. Notably, we have identified 19 novel fragment hits that inhibit FAAH with a median effective concentration (IC₅₀) in the low mM-μM range. To the best of our knowledge, these results represent the first application of a ¹⁹F NMR fragment-based functional assay to a membrane protein.
• Synthesis and Structure-activity Relationship (SAR) of 2-methyl-4-oxo-3-oxetanylcarbamic Acid Esters, a Class of Potent N-acylethanolamine Acid Amidase (NAAA) Inhibitors Journal of Medicinal Chemistry. Sep, 2013  |   Pubmed ID: 23991897 N-Acylethanolamine acid amidase (NAAA) is a lysosomal cysteine hydrolase involved in the degradation of saturated and monounsaturated fatty acid ethanolamides (FAEs), a family of endogenous lipid agonists of peroxisome proliferator-activated receptor-α, which include oleoylethanolamide (OEA) and palmitoylethanolamide (PEA). The β-lactone derivatives (S)-N-(2-oxo-3-oxetanyl)-3-phenylpropionamide (2) and (S)-N-(2-oxo-3-oxetanyl)-biphenyl-4-carboxamide (3) inhibit NAAA, prevent FAE hydrolysis in activated inflammatory cells, and reduce tissue reactions to pro-inflammatory stimuli. Recently, our group disclosed ARN077 (4), a potent NAAA inhibitor that is active in vivo by topical administration in rodent models of hyperalgesia and allodynia. In the present study, we investigated the structure-activity relationship (SAR) of threonine-derived β-lactone analogues of compound 4. The main results of this work were an enhancement of the inhibitory potency of β-lactone carbamate derivatives for NAAA and the identification of (4-phenylphenyl)-methyl-N-[(2S,3R)-2-methyl-4-oxo-oxetan-3-yl]carbamate (14q) as the first single-digit nanomolar inhibitor of intracellular NAAA activity (IC50 = 7 nM on both rat NAAA and human NAAA).
• Fluorine NMR-based Screening on Cell Membrane Extracts ChemMedChem. Feb, 2014  |   Pubmed ID: 24339446 The possibility of measuring the action of inhibitors of specific enzymatic reactions in intact cells, cell lysates or membrane preparations represents a major advance in the lead discovery process. Despite the relevance of assaying in physiological conditions, only a small number of biophysical techniques, often requiring complex set-up, are applicable to these sample types. Here, we demonstrate the first application of n-fluorine atoms for biochemical screening (n-FABS), a homogeneous and versatile assay based on (19) F NMR spectroscopy, to the detection of high- and low-affinity inhibitors of a membrane enzyme in cell extracts and determination of their IC50 values. Our approach can allow the discovery of novel binding fragments against targets known to be difficult to purify or where membrane-association is required for activity. These results pave the way for future applications of the methodology to these relevant and complex biological systems.
• Familial Malignant Mesothelioma: a Population-based Study in Central Italy (1980-2012) Cancer Epidemiology. Jun, 2014  |   Pubmed ID: 24684899 Malignant mesothelioma is a sporadic cancer linked to asbestos exposure. Its occurrence among blood relatives (familial mesothelioma) may point to genetic susceptibility or shared exposures. The burden of the familial disease is unknown. The aims of the study were to assess at population level the proportion of familial mesotheliomas among all mesotheliomas and to investigate the family history of cancer among relatives of mesothelioma cases. We actively searched familial clusters based on a mesothelioma registry from central Italy (5.5 million people, 10% of the Italian population) of the National Mesothelioma Register network (ReNaM) as well as a pathology-based archive. Among 997 incident mesotheliomas recorded in a 32-year-period (1980-2012), we detected 13 clusters and 34 familial cases, accounting for 3.4% of all mesotheliomas. The most common clusters where those with affected siblings and unaffected parents. Asbestos exposure was occupational (n=7 clusters), household (n=2), environmental (n=1), or not attributable for insufficient information (n=3). There were 25 additional cancers in nine families. Some were cancer sites for which there is sufficient evidence (lung and larynx) or limited evidence (stomach and colon) of causal association with asbestos. The results suggest potential genetic recessive effects in mesothelioma that interact with asbestos exposure, but it is not possible to estimate the specific proportion attributable to each of these components.
• A Potent Systemically Active N-Acylethanolamine Acid Amidase Inhibitor That Suppresses Inflammation and Human Macrophage Activation ACS Chemical Biology. Aug, 2015  |   Pubmed ID: 25874594 Fatty acid ethanolamides such as palmitoylethanolamide (PEA) and oleoylethanolamide (OEA) are lipid-derived mediators that potently inhibit pain and inflammation by ligating type-α peroxisome proliferator-activated receptors (PPAR-α). These bioactive substances are preferentially degraded by the cysteine hydrolase, N-acylethanolamine acid amidase (NAAA), which is highly expressed in macrophages. Here, we describe a new class of β-lactam derivatives that are potent, selective, and systemically active inhibitors of intracellular NAAA activity. The prototype of this class deactivates NAAA by covalently binding the enzyme's catalytic cysteine and exerts profound anti-inflammatory effects in both mouse models and human macrophages. This agent may be used to probe the functions of NAAA in health and disease and as a starting point to discover better anti-inflammatory drugs.
• Epidemiological Patterns of Asbestos Exposure and Spatial Clusters of Incident Cases of Malignant Mesothelioma from the Italian National Registry BMC Cancer. Apr, 2015  |   Pubmed ID: 25885893 Previous ecological spatial studies of malignant mesothelioma cases, mostly based on mortality data, lack reliable data on individual exposure to asbestos, thus failing to assess the contribution of different occupational and environmental sources in the determination of risk excess in specific areas. This study aims to identify territorial clusters of malignant mesothelioma through a Bayesian spatial analysis and to characterize them by the integrated use of asbestos exposure information retrieved from the Italian national mesothelioma registry (ReNaM).
• Activity-Based Probe for N-Acylethanolamine Acid Amidase ACS Chemical Biology. Sep, 2015  |   Pubmed ID: 26102511 N-Acylethanolamine acid amidase (NAAA) is a lysosomal cysteine hydrolase involved in the degradation of saturated and monounsaturated fatty acid ethanolamides (FAEs), a family of endogenous lipid signaling molecules that includes oleoylethanolamide (OEA) and palmitoylethanolamide (PEA). Among the reported NAAA inhibitors, α-amino-β-lactone (3-aminooxetan-2-one) derivatives have been shown to prevent FAE hydrolysis in innate-immune and neural cells and to reduce reactions to inflammatory stimuli. Recently, we disclosed two potent and selective NAAA inhibitors, the compounds ARN077 (5-phenylpentyl-N-[(2S,3R)-2-methyl-4-oxo-oxetan-3-yl]carbamate) and ARN726 (4-cyclohexylbutyl-N-[(S)-2-oxoazetidin-3-yl]carbamate). The former is active in vivo by topical administration in rodent models of hyperalgesia and allodynia, while the latter exerts systemic anti-inflammatory effects in mouse models of lung inflammation. In the present study, we designed and validated a derivative of ARN726 as the first activity-based protein profiling (ABPP) probe for the in vivo detection of NAAA. The newly synthesized molecule 1 is an effective in vitro and in vivo click-chemistry activity based probe (ABP), which is able to capture the catalytically active form of NAAA in Human Embryonic Kidney 293 (HEK293) cells overexpressing human NAAA as well as in rat lung tissue. Competitive ABPP with 1 confirmed that ARN726 and ARN077 inhibit NAAA in vitro and in vivo. Compound 1 is a useful new tool to identify activated NAAA both in vitro and in vivo and to investigate the physiological and pathological roles of this enzyme.
• Fluorine Nuclear Magnetic Resonance-based Assay in Living Mammalian Cells Analytical Biochemistry. Feb, 2016  |   Pubmed ID: 26686030 Nuclear magnetic resonance (NMR)-based screening has been recognized as a powerful approach for the identification and characterization of molecules interacting with pharmaceutical targets. Indeed, several NMR methods have been developed and successfully applied to many drug discovery projects. Whereas most of these approaches have targeted isolated biomolecular receptors, very few cases are reported with the screening performed in intact cells and cell extracts. Here we report the first successful application of the fluorine NMR-based assay n-FABS (n-fluorine atoms for biochemical screening) in living mammalian cells expressing the membrane protein fatty acid amide hydrolase (FAAH). This method allows the identification of both weak and potent inhibitors and the measurement of their potency in a physiological environment.
• [Time Trend in Mesothelioma and Lung Cancer Risk in Asbestos Workers in Italy] Epidemiologia E Prevenzione. Jan-Feb, 2016  |   Pubmed ID: 26951735 This study aims at investigating, in asbestos exposed workers, the time trend of their risk of mesothelioma and of other neoplasm after very long latency and after the cessation of asbestos exposure. We pooled a large number of Italian cohorts of asbestos workers and updated mortality follow-up. The pool of data for statistical analyses includes 51,988 workers, of which 6,058 women: 54.2% was alive at follow-up, 42.6% was dead, and 2.8%was lost. Cause of death is known for 94.3%: 2,548 deaths from lung cancer, 748 frompleural cancer, 173 fromperitoneal cancer, and 434 from asbestosis. An exposure index is being developed to compare the different cohorts. Data analysis is in progress. This study will have the size for analysing not only time trends in mesothelioma, but also the occurrence of rarer diseases and cancer specific mortality in women.
• Second-Generation Non-Covalent NAAA Inhibitors Are Protective in a Model of Multiple Sclerosis Angewandte Chemie (International Ed. in English). Sep, 2016  |   Pubmed ID: 27404798 Palmitoylethanolamide (PEA) and oleoylethanolamide (OEA) are endogenous lipid mediators that suppress inflammation. Their actions are terminated by the intracellular cysteine amidase, N-acylethanolamine acid amidase (NAAA). Even though NAAA may offer a new target for anti-inflammatory therapy, the lipid-like structures and reactive warheads of current NAAA inhibitors limit the use of these agents as oral drugs. A series of novel benzothiazole-piperazine derivatives that inhibit NAAA in a potent and selective manner by a non-covalent mechanism are described. A prototype member of this class (8) displays high oral bioavailability, access to the central nervous system (CNS), and strong activity in a mouse model of multiple sclerosis (MS). This compound exemplifies a second generation of non-covalent NAAA inhibitors that may be useful in the treatment of MS and other chronic CNS disorders.
• Pathology Reporting of Malignant Pleural Mesothelioma First Diagnosis: A Population-based Approach Pathology, Research and Practice. Oct, 2016  |   Pubmed ID: 27485167 Accurate pathologic diagnosis and reporting in malignant pleural mesothelioma are essential for clinical care, and cancer registration. Practical guidelines for pathologists are provided in publications and textbooks but it is unclear how these recommendations are applied in routine practice. We investigated the characteristics of pathology reports, and the extent to which they meet guideline standards. We reviewed 819 pathology reports relating to a first diagnosis of malignant pleural mesothelioma. Data sources were a regional section of the Italian network of the Mesothelioma Registry (2001-2014) and a pathology archive (1990-2000). We evaluated tumor characteristics, the diagnosis field including terminology and immunohistochemistry (IHC) workup, and report completeness (the proportion of items recorded). We investigated also two IHC panels identified by the most used markers in current practical guidelines, one best suited for epithelioid mesotheliomas (combinations of at least 2 positive and at least 2 negative mesothelioma markers) and the other best suited for sarcomatoid mesotheliomas (positive mesothelioma markers plus cytokeratins). Reports (753 histology, 66 cytology, IHC-confirmed 86%) were 74% complete and always narrative. Missing data were related to clinical history (76%), tumor laterality (61%), specimen size (38%), and histological subtype (23%). The proportion of cases with IHC was higher for epithelioid (90%) than sarcomatoid mesothelioma (87%). Compliance to IHC recommendations was higher for epithelioid (59%) than sarcomatoid mesothelioma (11%). The mean number of stains was significantly higher for sarcomatoid than epithelioid mesothelioma (p
• Bile Acid Recognition by NAPE-PLD ACS Chemical Biology. Oct, 2016  |   Pubmed ID: 27571266 The membrane-associated enzyme NAPE-PLD (N-acyl phosphatidylethanolamine specific-phospholipase D) generates the endogenous cannabinoid arachidonylethanolamide and other lipid signaling amides, including oleoylethanolamide and palmitoylethanolamide. These bioactive molecules play important roles in several physiological pathways including stress and pain response, appetite, and lifespan. Recently, we reported the crystal structure of human NAPE-PLD and discovered specific binding sites for the bile acid deoxycholic acid. In this study, we demonstrate that in the presence of this secondary bile acid, the stiffness of the protein measured by elastic neutron scattering increases, and NAPE-PLD is ∼7 times faster to catalyze the hydrolysis of the more unsaturated substrate N-arachidonyl-phosphatidylethanolamine, compared with N-palmitoyl-phosphatidylethanolamine. Chenodeoxycholic acid and glyco- or tauro-dihydroxy conjugates can also bind to NAPE-PLD and drive its activation. The only natural monohydroxy bile acid, lithocholic acid, shows an affinity of ∼20 μM and acts instead as a reversible inhibitor (IC50 ≈ 68 μM). Overall, these findings provide important insights into the allosteric regulation of the enzyme mediated by bile acid cofactors and reveal that NAPE-PLD responds primarily to the number and position of their hydroxyl groups.
• Mesothelioma Families Without Inheritance of a BAP1 Predisposing Mutation Cancer Genetics. Sep, 2016  |   Pubmed ID: 27751355 Familial malignant mesothelioma clusters are ideal candidates to explore BAP1 genomic status as a predisposing risk factor. We report data on BAP1 analysis in four families with multiple mesothelioma cases to investigate possible BAP1 alterations associated with an inherited cancer syndrome. We also recorded family history of cancer and assessed asbestos exposure. By genomic direct sequencing, we found no evidence of a BAP1 germline mutation in tumor DNA samples (one mesothelioma per family: n = 3 epithelioid; n = 1 biphasic). On the other hand, we identified a novel BAP1 somatic alteration (c.329_335delinsTC) in exon 5 (n = 1 biphasic), and we hypothesized the occurrence of somatic inactivating events not identifiable by sequencing in the other cases (n = 3 epithelioid), as demonstrated by the loss of nuclear BAP1 immunostaining. History of other cancers was in sites not typical of the BAP1 cancer syndrome. Asbestos exposure was occupational (n = 2 clusters), household (n = 1), and unknown (n = 1). These family units without inheritance of a BAP1 predisposing mutation expand the number of unmutated germline BAP1 families with multiple mesothelioma cases. This suggests that besides the exposure to asbestos other currently unknown genetic or epigenetic factors may be responsible for the high incidence of mesothelioma in BAP1-unmutated families.