IL-1R8 is a checkpoint in NK cells regulating anti-tumour and anti-viral activity

Interleukin-1 receptor 8 (IL-1R8, also known as single immunoglobulin IL-1R-related receptor, SIGIRR, or TIR8) is a member of the IL-1 receptor (ILR) family with distinct structural and functional characteristics, acting as a negative regulator of ILR and Toll-like receptor (TLR) downstream signalling pathways and inflammation. Natural killer (NK) cells are innate lymphoid cells which mediate resistance against pathogens and contribute to the activation and orientation of adaptive immune responses. NK cells mediate resistance against haematopoietic neoplasms but are generally considered to play a minor role in solid tumour carcinogenesis. Here we report that IL-1R8 serves as a checkpoint for NK cell maturation and effector function. Its genetic blockade unleashes NK-cell-mediated resistance to hepatic carcinogenesis, haematogenous liver and lung metastasis, and cytomegalovirus infection

Role of chemokine/chemokine receptor axes in the regulation of bone marrow NK cell localization in physiological and pathological conditions

Natural Killer (NK) cells represent a lymphocyte population of the innate immunity, involved in the control of viral infections and tumor cells. Among the wide number of functions that NK cells can mediate, the most important are the ability to lyse target cells via the release of cytotoxic granules, and the production of pro-inflammatory mediators, such as cytokines and chemokines. In mouse, according to the expression of the surface markers CD11b and KLRG1, within the NK cell population 4 discrete subsets can be distinguished, which represent different developmental stages and show heterogeneous functional capacities. Moreover, their tissue localization is dissimilar in primary and secondary lymphoid organs, and in non-lymphoid organs: the most immature populations are mainly represented in the bone marrow (BM), thymus and lymph nodes (LN), while the most mature ones preferentially distribute in blood, spleen, liver and lungs. Chemokines are chemotactic molecules of proteic nature, which bind specific GPCR receptors, and direct the migration of several cell types through the formation of a concentration gradient. NK cells express a great variety of chemokine receptors, which regulate their organ distribution and their trafficking to inflamed tissues. The first part of this work dealt with the study of the function of CX3CR1 receptor, specific for the chemokine CX3CL1, in the NK cell positioning in the BM microenvironment. To this aim, a murine knock-in model, in which one or both copies of cx3cr1 gene were replaced by GFP cDNA, was used. Through the analysis of GFP expression it was possible to track CX3CR1+ NK cells in heterozygous mice, or the cells that should express CX3CR1, but express only GFP, in the homozygous mice. Data obtained by adoptive transfer experimental approaches, single or mixed BM chimeras and the phenotyping of NK cells in BM compartments, demonstrated that CX3CR1 is expressed by a terminally differentiated subset, which mainly resides in the vascular compartment of the BM, and displays reduced effector functions. Moreover, CX3CR1 was associated to a positive regulation in the exit of most mature NK cells from the BM towards the periphery, similarly to what was previously demonstrated for S1P5. Data regarding these studies have been published in two international peer-reviewed journals. The second part of this thesis work was centered on the influence of multiple myeloma (MM) growth on the functional and trafficking capacities of BM NK cells, in a murine model of this pathology. MM was followed at different growth stages, and we observed the selective exclusion from BM of the most functional NK cell subpopulation (KLRG1-), at an intermediate stage of tumor progression. Adoptive transfer experiments on healthy controls and MM-bearing mice have elucidated that the KLRG1- NK cell reduction was attributable to a trafficking alteration within BM. We analysed the mechanism of this phenomenon, by studying the production of several chemokines and the expression of many chemokine receptors on BM NK cells in presence or absence of MM. At the same stage of MM growth we observed a decrease of CXCR3 expression, while its ligands CXCL9 and CXCL10 were augmented in tumor-bearing mice. Furthermore, CXCL9 concentration was higher as compared to healthy controls also in the sera in MM-bearing mice.In parallel, we highlighted that CXCR4/CXCL12 axis was altered too, as CXCL12 level was significantly lower in the BM of tumor-bearing mice. With competitive adoptive transfer experiments, we demonstrated that CXCR3+ NK cells are selectively excluded from BM, and accumulate in liver and spleen. Globally these data suggest a strategy for the tumor cells to evade the NK-cell mediated effect in the tumor microenvironment, by altering directly or indirectly different chemokine/receptor axes, important for BM NK cell migration

Il Giardino di Ninfa. Un'applicazione BIM per la conservazione dei ruderi

Il lavoro offre un contributo, nell’ambito del restauro, relativo alla definizione di un metodo di valutazione dello stato conservativo dei ruderi del Giardino di Ninfa, mediante la definizione e la gestione in ambiente BIM di parametri quantitativi e qualitativi, al fine di elaborare un piano di manutenzione programmata e di gestione degli interventi

Un metodo per l'elaborazione del piano di manutenzione dopo il restauro

Questo contributo ha come finalità la presentazione di un metodo per l’elaborazione del piano di manutenzione del Palazzo della Cancelleria a Roma, atto a preservare la materia restaurata, che si caratterizzi per praticità ed efficienza. Il sistema che si propone prevede l’utilizzo della tecnologia Building Information Modeling, attraverso la quale sarà possibile ottimizzare tempo e risorse economiche, organizzando le attività in grado di controllare, correggere e rallentare il normale degrado dei materiali costituenti l’opera architettonica

CX3CR1 Regulates the Maintenance of KLRG1+ NK Cells into the Bone Marrow by Promoting Their Entry into Circulation

NK cell differentiation mainly occurs in the bone marrow (BM) where a critical role in the regulation of developing lymphocyte distribution is played by members of the chemokine receptor family. In mouse, the chemokine receptor CX3CR1 identifies a late stage of NK cell development characterized by decreased effector functions and expression of the inhibitory receptor KLRG1. The role of CX3CR1 in the regulation of differentiation and positioning of NK cell subsets in the BM is not known. In this study, we found that CX3CR1 deficiency leads to accumulation of KLRG1(+) NK cells in BM during steady-state conditions. The NK cell subset that expresses the receptor in wild-type mice was expanded in several tissues of CX3CR1-deficient mice, and NK cell degranulation in response to sensitive target cell stimulation was enhanced, suggesting a regulatory role of CX3CR1 in NK cell positioning and differentiation in BM. Indeed, the observed NK cell expansion was not due to altered turnover rate, whereas it was associated with preferential accumulation in the BM parenchyma. In addition, a role of CX3CR1 in NK cell trafficking from BM and spleen was evidenced also during inflammation, as CX3CR1-deficient NK cells were more prompt to exit the BM and did not decrease in spleen in response to polyinosinic-polycytidylic acid-promoted hepatitis. Overall, our results evidenced a relevant role of CX3CR1 in the regulation of NK cell subset exit from BM during homeostasis, and suggest that defect in the CX3CR1/CX3CL1 axis alters NK cell trafficking and functional response during inflammatory conditions

CX3CR1 expression defines 2 KLRG1+ mouse NK-cell subsets with distinct functional properties and positioning in the bone marrow

During development in the bone marrow (BM), NK-cell positioning within specific niches can be influenced by expression of chemokine or adhesion receptors. We previously demonstrated that the maintenance in the BM of selected NK-cell subsets is regulated by the CXCR4/CXCL12 axis. In the present study, we showed that CX3CR1 is prevalently expressed on KLRG1(+) NK cells, a subset considered terminally differentiated. Two KLRG1(+) NK-cell populations endowed with distinct homing and functional features were defined according to CX3CR1 expression. In the BM, KLRG1(+)/CX3CR1(-) NK cells were mainly positioned into parenchyma, while KLRG1(+)/CX3CR1(+) NK cells exhibited reduced CXCR4 expression and were preferentially localized in the sinusoids. We also showed that alpha(4) integrin plays a pivotal role in the maintenance of NK cells in the BM sinusoids and that alpha(4) neutralization leads to strong reduction of BM KLRG1(+)/CX3CR1(+) NK cells. Moreover, we found that KLRG1(+)/CX3CR1(+) cells originate from KLRG1(+)/CX3CR1(-) NK-cell population and display impaired capability to produce IFN-gamma and to lyse YAC-1 target cells on cytokine stimulation. Altogether, our findings show that CX3CR1 represents a marker of a KLRG1(+) NK-cell population with unique properties that can irreversibly differentiate from the KLRG1(+)/CX3CR1(-) NK cells during steady state conditions. (Blood. 2011; 117(17): 4467-4475

CX3CL1 protects neurons against excitotoxicity enhancing GLT-1 activity on astrocytes

In this paper we show for the first time that: i) astrocytes are required for the neuroprotective activity of CX3CL1 against excitotoxicity; ii) inhibition of the glutamate transporter 1 (GLT-1) prejudices CX3CL1-mediated neuroprotection; iii) CX3CL1 increases GLT-1 activity on astrocytes. The modulation of GLT-1 activity induced by CX3CL1 on astrocytes requires the presence and the activity of A1 adenosine receptor (A1R), being blocked by the specific antagonist DPCPX and absent in A1R-/- astrocytes. These data introduce the astrocytes as active players in CX3CL1-mediated signaling between microglia and neurons, identifying GLT-1 as a key mediator of the neuroprotective activity of CX3CL1. © 2013 Elsevier B.V

Multiple Myeloma Impairs Bone Marrow Localization of Effector Natural Killer Cells by Altering the Chemokine Microenvironment.

Natural killer (NK) cells are key innate immune effectors against multiple myeloma, their activity declining in multiple myeloma patients with disease progression. To identify the mechanisms underlying NK cell functional impairment, we characterized the distribution of functionally distinct NK cell subsets in the bone marrow of multiple myeloma-bearing mice. Herein we report that the number of KLRG1(-) NK cells endowed with potent effector function rapidly and selectively decreases in bone marrow during multiple myeloma growth, this correlating with decreased bone marrow NK cell degranulation in vivo. Altered NK cell subset distribution was dependent on skewed chemokine/chemokine receptor axes in the multiple myeloma microenvironment, with rapid downmodulation of the chemokine receptor CXCR3 on NK cells, increased CXCL9 and CXCL10, and decreased CXCL12 expression in bone marrow. Similar alterations in chemokine receptor/chemokine axes were observed in patients with multiple myeloma. Adoptive transfer experiments demonstrated that KLRG1(-) NK cell migration to the bone marrow was more efficient in healthy than multiple myeloma-bearing mice. Furthermore, bone marrow localization of transferred CXCR3-deficient NK cells with respect to wild type was enhanced in healthy and multiple myeloma-bearing mice, suggesting that CXCR3 restrains bone marrow NK cell trafficking. Our results indicate that multiple myeloma-promoted CXCR3 ligand upregulation together with CXCL12 downmodulation act as exit signals driving effector NK cells outside the bone marrow, thus weakening the antitumor immune response at the primary site of tumor growt