Divergent roles for STAT4 in shaping differentiation of cytotoxic ILC1 and NK cells during gut inflammation.

Natural killer (NK) cells and type 1 innate lymphoid cells (ILC1) require signal transducer and activator of transcription 4 (STAT4) to elicit rapid effector responses and protect against pathogens. By combining genetic and transcriptomic approaches, we uncovered divergent roles for STAT4 in regulating effector differentiation of these functionally related cell types. Stat4 deletion in Ncr1-expressing cells led to impaired NK cell terminal differentiation as well as to an unexpected increased generation of cytotoxic ILC1 during intestinal inflammation. Mechanistically, Stat4-deficient ILC1 exhibited upregulation of gene modules regulated by STAT5 in vivo and an aberrant effector differentiation upon in vitro stimulation with IL-2, used as a prototypical STAT5 activator. Moreover, STAT4 expression in NCR+ innate lymphocytes restrained gut inflammation in the dextran sulfate sodium-induced colitis model limiting pathogenic production of IL-13 from adaptive CD4+ T cells in the large intestine. Collectively, our data shed light on shared and distinctive mechanisms of STAT4-regulated transcriptional control in NK cells and ILC1 required for intestinal inflammatory responses.

Cardiac Aging Is Promoted by Pseudohypoxia Increasing p300-Induced Glycolysis.

BACKGROUND: Heart failure is typical in the elderly. Metabolic remodeling of cardiomyocytes underlies inexorable deterioration of cardiac function with aging: glycolysis increases at the expense of oxidative phosphorylation, causing an energy deficit contributing to impaired contractility. Better understanding of the mechanisms of this metabolic switching could be critical for reversing the condition. METHODS: To investigate the role of 3 histone modifications (H3K27ac, H3K27me3, and H3K4me1) in the metabolic remodeling occurring in the aging heart, we cross-compared epigenomic, transcriptomic, and metabolomic data from mice of different ages. In addition, the role of the transcriptional coactivator p300 (E1A-associated binding protein p300)/CBP (CREB binding protein) in cardiac aging was investigated using a specific inhibitor of this histone acetyltransferase enzyme. RESULTS: We report a set of species-conserved enhancers associated with transcriptional changes underlying age-related metabolic remodeling in cardiomyocytes. Activation of the enhancer region of Hk2-a key glycolysis pathway gene-was fostered in old age-onset mouse heart by pseudohypoxia, wherein hypoxia-related genes are expressed under normal O2 levels, via increased activity of P300/CBP. Pharmacological inhibition of this transcriptional coactivator before the onset of cardiac aging led to a more aerobic, less glycolytic, metabolic state, improved heart contractility, and overall blunting of cardiac decline. CONCLUSIONS: Taken together, our results suggest how epigenetic dysregulation of glycolysis pathway enhancers could potentially be targeted to treat heart failure in the elderly.

Iron Oxide Nanoparticles with and without Cobalt Functionalization Provoke Changes in the Transcription Profile via Epigenetic Modulation of Enhancer Activity.

Despite the progress in the field of nanotoxicology, much about the cellular mechanisms that mediate the adverse effects of nanoparticles (NPs) and, in particular, the possible role of epigenetics in nanotoxicity, remains to be clarified. Therefore, we studied the changes occurring in the genome-wide distribution of H3K27ac, H3K4me1, H3K9me2, and H3K27me3 histone modifications and compared them with the transcriptome after exposing NIH3T3 cells to iron-based magnetic NPs (i.e., Fe2O3 and Fe2O3@Co NPs). We found that the transcription response is mainly due to changes in the genomic distribution of H3K27ac that can modulate the activity of enhancers. We propose that alteration of the epigenetic landscape is a key mechanism in defining the gene expression program changes resulting in nanotoxicity. With this approach, it is possible to construct a data set of genomic regions that could be useful for defining toxicity in a manner that is more comprehensive than what is possible with the present toxicology assays.

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.

Microglia modulate hippocampal synaptic transmission and sleep duration along the light/dark cycle.

Microglia, the brain's resident macrophages, actively contribute to the homeostasis of cerebral parenchyma by sensing neuronal activity and supporting synaptic remodeling and plasticity. While several studies demonstrated different roles for astrocytes in sleep, the contribution of microglia in the regulation of sleep/wake cycle and in the modulation of synaptic activity in the different day phases has not been deeply investigated. Using light as a zeitgeber cue, we studied the effects of microglial depletion with the colony stimulating factor-1 receptor antagonist PLX5622 on the sleep/wake cycle and on hippocampal synaptic transmission in male mice. Our data demonstrate that almost complete microglial depletion increases the duration of NREM sleep and reduces the hippocampal excitatory neurotransmission. The fractalkine receptor CX3CR1 plays a relevant role in these effects, because cx3cr1GFP/GFP mice recapitulate what found in PLX5622-treated mice. Furthermore, during the light phase, microglia express lower levels of cx3cr1 and a reduction of cx3cr1 expression is also observed when cultured microglial cells are stimulated by ATP, a purinergic molecule released during sleep. Our findings suggest that microglia participate in the regulation of sleep, adapting their cx3cr1 expression in response to the light/dark phase, and modulating synaptic activity in a phase-dependent manner.

Granzyme A and CD160 expression delineates ILC1 with graded functions in the mouse liver.

Type 1 innate lymphoid cells (ILC1) are tissue-resident lymphocytes that provide early protection against bacterial and viral infections. Discrete transcriptional states of ILC1 have been identified in homeostatic and pathological contexts. However, whether these states delineate ILC1 with different functional properties is not completely understood. Here, we show that liver ILC1 are heterogeneous for the expression of distinct effector molecules and surface receptors, including granzyme A (GzmA) and CD160, in mice. ILC1 expressing high levels of GzmA are enriched in the liver of adult mice, and represent the main hepatic ILC1 population at birth. However, the heterogeneity of GzmA and CD160 expression in hepatic ILC1 begins perinatally and increases with age. GzmA+ ILC1 differ from NK cells for the limited homeostatic requirements of JAK/STAT signals and the transcription factor Nfil3. Moreover, by employing Rorc(γt)-fate map (fm) reporter mice, we established that ILC3-ILC1 plasticity contributes to delineate the heterogeneity of liver ILC1, with RORγt-fm+ cells skewed toward a GzmA- CD160+ phenotype. Finally, we showed that ILC1 defined by the expression of GzmA and CD160 are characterized by graded cytotoxic potential and ability to produce IFN-γ. In conclusion, our findings help deconvoluting ILC1 heterogeneity and provide evidence for functional diversification of liver ILC1.

Blocking immune cell infiltration of the central nervous system to tame Neuroinflammation in Amyotrophic lateral sclerosis.

Neuroinflammation is one of the main hallmarks of amyotrophic lateral sclerosis (ALS). Recently, peripheral immune cells were discovered as pivotal players that promptly participate in this process, speeding up neurodegeneration during progression of the disease. In particular, infiltrating T cells and natural killer cells release inflammatory cytokines that switch glial cells toward a pro-inflammatory/detrimental phenotype, and directly attack motor neurons with specific ligand-receptor signals. Here, we assessed the presence of lymphocytes in the spinal cord of sporadic ALS patients. Furthermore, we demonstrate that blocking the extravasation of immune cells in the central nervous system using Natalizumab (NAT), an antibody for the α4 integrin, reduces the level of interferon-γ in the spinal cord of ALS mouse models, such as the hSOD1G93A and TDP43A315T mice, modifying microglia and astrocytes phenotype, increasing motor neuron number and prolonging the survival time. Taken together, our results establish a central role for the immune cells as drivers of inflammation in ALS.

Copper oxide nanoparticles trigger macrophage cell death with misfolding of Cu/Zn superoxide dismutase 1 (SOD1).

BACKGROUND: Copper oxide (CuO) nanoparticles (NPs) are known to trigger cytotoxicity in a variety of cell models, but the mechanism of cell death remains unknown. Here we addressed the mechanism of cytotoxicity in macrophages exposed to CuO NPs versus copper chloride (CuCl2). METHODS: The mouse macrophage cell line RAW264.7 was used as an in vitro model. Particle uptake and the cellular dose of Cu were investigated by transmission electron microscopy (TEM) and inductively coupled plasma mass spectrometry (ICP-MS), respectively. The deposition of Cu in lysosomes isolated from macrophages was also determined by ICP-MS. Cell viability (metabolic activity) was assessed using the Alamar Blue assay, and oxidative stress was monitored by a variety of methods including a luminescence-based assay for cellular glutathione (GSH), and flow cytometry-based detection of mitochondrial superoxide and mitochondrial membrane potential. Protein aggregation was determined by confocal microscopy using an aggresome-specific dye and protein misfolding was determined by circular dichroism (CD) spectroscopy. Lastly, proteasome activity was investigated using a fluorometric assay. RESULTS: We observed rapid cellular uptake of CuO NPs in macrophages with deposition in lysosomes. CuO NP-elicited cell death was characterized by mitochondrial swelling with signs of oxidative stress including the production of mitochondrial superoxide and cellular depletion of GSH. We also observed a dose-dependent accumulation of polyubiquitinated proteins and loss of proteasomal function in CuO NP-exposed cells, and we could demonstrate misfolding and mitochondrial translocation of superoxide dismutase 1 (SOD1), a Cu/Zn-dependent enzyme that plays a pivotal role in the defense against oxidative stress. The chelation of copper ions using tetrathiomolybdate (TTM) prevented cell death whereas inhibition of the cellular SOD1 chaperone aggravated toxicity. Moreover, CuO NP-triggered cell death was insensitive to the pan-caspase inhibitor, zVAD-fmk, and to wortmannin, an inhibitor of autophagy, implying that this was a non-apoptotic cell death. ZnO NPs, on the other hand, triggered autophagic cell death. CONCLUSIONS: CuO NPs undergo dissolution in lysosomes leading to copper-dependent macrophage cell death characterized by protein misfolding and proteasomal insufficiency. Specifically, we present novel evidence for Cu-induced SOD1 misfolding which accords with the pronounced oxidative stress observed in CuO NP-exposed macrophages. These results are relevant for our understanding of the consequences of inadvertent human exposure to CuO NPs.

Histone-deacetylase 8 drives the immune response and the growth of glioma.

Many epigenetic modifications occur in glioma, in particular the histone-deacetylase class proteins play a pivotal role in glioma development, driving the proliferation rate and the invasiveness of tumor cells, and modulating the tumor microenvironment. In this study, we evaluated the role of the histone deacetylase HDAC8 in the regulation of the immune response in glioma and tumor growth. We found that inhibition of HDAC8 by the specific inhibitor PCI-34051 reduces tumor volume in glioma mouse models. We reported that HDAC8 modulates the viability and the migration of human and murine glioma cells. Interestingly, HDAC8 inhibition increases the acetylation of alpha-tubulin, suggesting this epigenetic modification controls glioma migration. Furthermore, we identify HDAC8 as a key molecule that supports a poorly immunogenic tumor microenvironment, modulating microglial phenotype and regulating the gene transcription of NKG2D ligands that trigger the Natural Killer cell-mediated cytotoxicity of tumor cells. Altogether, these results identify HDAC8 as a key actor in glioma growth and tumor microenvironment, and pave the way to a better knowledge of the molecular mechanisms of immune escape in glioma.

Epigenetics of aging and disease: a brief overview.

Aging is an important risk factor for several human diseases such as cancer, cardiovascular disease and neurodegenerative disorders, resulting from a combination of genetic and environmental factors (e.g., diet, smoking, obesity and stress), which, at molecular level, cause changes in gene expression underlying the decline of physiological function. Epigenetics, which include mechanisms regulating gene expression independently of changes to DNA sequence, regulate gene expression by modulating the structure of chromatin or by regulating the binding of transcriptional machinery to DNA. Several studies showed that an impairment of epigenetic mechanisms promotes alteration of gene expression underlying several aging-related diseases. Alteration of these mechanisms is also linked with changes of gene expression that occurs during aging processes of different tissues. In this review, we will outline the potential role of epigenetics in the onset of two age-related pathologies, cancer and cardiovascular diseases.

CXCR3/CXCL10 Axis Regulates Neutrophil-NK Cell Cross-Talk Determining the Severity of Experimental Osteoarthritis.

Several immune cell populations are involved in cartilage damage, bone erosion, and resorption processes during osteoarthritis. The purpose of this study was to investigate the role of NK cells in the pathogenesis of experimental osteoarthritis and whether and how neutrophils can regulate their synovial localization in the disease. Experimental osteoarthritis was elicited by intra-articular injection of collagenase in wild type and Cxcr3-/- 8-wk old mice. To follow osteoarthritis progression, cartilage damage, synovial thickening, and osteophyte formation were measured histologically. To characterize the inflammatory cells involved in osteoarthritis, synovial fluid was collected early after disease induction, and the cellular and cytokine content were quantified by flow cytometry and ELISA, respectively. We found that NK cells and neutrophils are among the first cells that accumulate in the synovium during osteoarthritis, both exerting a pathogenic role. Moreover, we uncovered a crucial role of the CXCL10/CXCR3 axis, with CXCL10 increasing in synovial fluids after injury and Cxcr3-/- mice being protected from disease development. Finally, in vivo depletion experiments showed that neutrophils are involved in an NK cell increase in the synovium, possibly by expressing CXCL10 in inflamed joints. Thus, neutrophils and NK cells act as important disease-promoting immune cells in experimental osteoarthritis and their functional interaction is promoted by the CXCL10/CXCR3 axis.

Nano-delivery of trace minerals for marine fish larvae: influence on skeletal ossification, and the expression of genes involved in intestinal transport of minerals, osteoblast differentiation, and oxidative stress response.

Currently, the larviculture of many marine fish species with small-sized larvae depends for a short time after hatching, on the supply of high-quality live zooplankton to ensure high survival and growth rates. During the last few decades, the research community has made great efforts to develop artificial diets, which can completely substitute live prey. However, studies aimed at determining optimal levels of minerals in marine larvae compound feeds and the potential of novel delivery vectors for mineral acquisition has only very recently begun. Recently, the agro-food industry has developed several nano-delivery systems, which could be used for animal feed, too. Delivery through nano-encapsulation of minerals and feed additives would protect the bioactive molecules during feed manufacturing and fish feeding and allow an efficient acquisition of active substances into biological system. The idea is that dietary minerals in the form of nanoparticles may enter cells more easily than their larger counterparts enter and thus speed up their assimilation in fish. Accordingly, we evaluated the efficacy of early weaning diets fortified with organic, inorganic, or nanoparticle forms of trace minerals (Se, Zn, and Mn) in gilthead seabream (Sparus aurata) larvae. We tested four experimental diets: a trace mineral-deficient control diet, and three diets supplemented with different forms of trace minerals. At the end of the feeding trial, larvae growth performance and ossification, and the level of expression of six target genes (SLC11A2ß, dmt1, BMP2, OC, SOD, GPX), were evaluated. Our data demonstrated that weaning diets supplemented with Mn, Se, and Zn in amino acid-chelated (organic) or nanoparticle form were more effective than diets supplemented with inorganic form of minerals to promote bone mineralization, and prevent skeletal anomalies in seabream larvae. Furthermore, nanometals markedly improved larval stress resistance in comparison to inorganic minerals and upregulated mRNA copy number of OC gene. The expression of this gene was strongly correlated with mineralization degree, thus confirming its potency as a good marker of bone mineralization in gilthead seabream larvae.

The Multifunctional Role of the Chemokine System in Arthritogenic Processes.

PURPOSE OF REVIEW: The involvement of chemokines and their receptors in the genesis and perpetuation of rheumatoid arthritis, spondyloarthritis, and osteoarthritis has been clearly recognized for a long time. Nevertheless, the complexity of their contribution to these diseases is now becoming evident and this review focuses on published evidence on their mechanism of action. RECENT FINDINGS: Studies performed on patients and in vivo models have identified a number of chemokine-mediated pathways involved in various aspects of arthritogenic processes. Chemokines promote leukocyte infiltration and activation, angiogenesis, osteoclast differentiation, and synoviocyte proliferation and activation and participate to the generation of pain by regulating the release of neurotransmitters. A number of chemokines are expressed in a timely controlled fashion in the joint during arthropathies, regulating all the aspects of inflammation as well as the equilibrium between damage and repair and between relief and pain. Thus, the targeting of specific chemokine/chemokine receptor interactions is considered a promising tool for therapeutic intervention.

Zerovalent Fe, Co and Ni nanoparticle toxicity evaluated on SKOV-3 and U87 cell lines.

We have considered nanoparticles (NPs) of Fe, Co and Ni, three transition metals sharing similar chemical properties. NP dissolution, conducted by radioactive tracer method and inductively coupled plasma mass spectrometry, indicated that NiNPs and FeNPs released in the medium a much smaller amount of ions than that released by Co NPs. The two considered methodological approaches, however, gave comparable but not identical results. All NPs are readily internalized by the cells, but their quantity inside the cells is less than 5%. Cytotoxicity and gene expression experiments were performed on SKOV-3 and U87 cells. In both cell lines, CoNPs and NiNPs were definitely more toxic than FeNPs. Real-time polymerase chain reaction experiments aimed to evaluate modifications of the expression of genes involved in the cellular stress response (HSP70, MT2A), or susceptible to metal exposure (SDHB1 and MLL), or involved in specific cellular processes (caspase3, IQSEC1 and VMP1), gave different response patterns in the two cell lines. HSP70, for example, was highly upregulated by CoNPs and NiNPs, but only in SKOV-3 cell lines. Overall, this work underlines the difficulties in predicting NP toxicological properties based only on their chemical characteristics. We, consequently, think that, at this stage of our knowledge, biological effects induced by metal-based NPs should be examined on a case-by-case basis following studies on different in vitro models. Moreover, with the only exception of U87 exposed to Ni, our results suggest that metallic NPs have caused, on gene expression, similar effects to those caused by their corresponding ions.

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.

Engineered metal based nanoparticles and innate immunity.

Almost all people in developed countries are exposed to metal nanoparticles (MeNPs) that are used in a large number of applications including medical (for diagnostic and therapeutic purposes). Once inside the body, absorbed by inhalation, contact, ingestion and injection, MeNPs can translocate to tissues and, as any foreign substance, are likely to encounter the innate immunity system that represent a non-specific first line of defense against potential threats to the host. In this review, we will discuss the possible effects of MeNPs on various components of the innate immunity (both specific cells and barriers). Most important is that there are no reports of immune diseases induced by MeNPs exposure: we are operating in a safe area. However, in vitro assays show that MeNPs have some effects on innate immunity, the main being toxicity (both cyto- and genotoxicity) and interference with the activity of various cells through modification of membrane receptors, gene expression and cytokine production. Such effects can have both negative and positive relevant impacts on humans. On the one hand, people exposed to high levels of MeNPs, as workers of industries producing or applying MeNPs, should be monitored for possible health effects. On the other hand, understanding the modality of the effects on immune responses is essential to develop medical applications for MeNPs. Indeed, those MeNPs that are able to stimulate immune cells could be used to develop of new vaccines, promote immunity against tumors and suppress autoimmunity.

Endovenous laser ablation of great saphenous veins performed using tumescent cold saline solution without local anesthesia.

BACKGROUND: In recent years, laser systems with higher wavelengths, associated with new optical fibers, have shown excellent short-term results in treating saphenous veins and reducing the side effects and, in particular, the postoperative pain. However, if the patients are not anesthetized, they may feel pain even when using low energy with the high-wavelength laser; the only tumescent local anesthesia often does not guarantee a complete pain control during endovenous laser ablation (EVLA). Aim of this study was to demonstrate that the local anesthesia during EVLA of great saphenous veins (GSVs) is not essential for the perioperative comfort of the patient if a mild sedation is made. METHODS: Forty-nine incompetent GSVs were treated by EVLA with a cold saline tumescent solution (CSTS) without local anesthetic drugs. EVLA was performed with a 1540-nm diode laser and a 600-µc ball-tipped fiber. Intraoperative ultrasonography was then used to guide delivery of CSTS (cold saline solution 0.9% at 5°C) using a motor pump under intravenous sedation. The gravity of chronic venous disease was determined according to the clinical-etiology-anatomy-pathophysiology classification. Patients rated surgery global pain according to 4 types: "extremely," "rather," "slightly," and "not at all" painful. RESULTS: Twenty-five cases (51%) were classified as C3, 20 (41%) as C2, 6 (13%) as C4, and 1 (2%) as C6. Midazolam 2.5 mg + a mean of 0.16 mg of fentanil (minimum: 0.10; maximum: 0.20; standard deviation [SD]: 0.4) + a mean of 178.21 mg of propofol (minimum: 100; maximum: 300; SD: 47.1) were administrated as intravenous sedation. The total average linear endovenous energy density was 57.7 J/cm. Approximately 250 mL (minimum: 100; maximum: 780) of CSTS was administered. No Patient has had pain during the procedure. All patients were discharged 2.5 hrs after surgery. CONCLUSIONS: EVLA under sedation using CSTS without diluted anesthetic drugs is a suitable technique in an outpatients clinic, especially useful if the ablation of the saphenous vein is combined with an extended phlebectomy or if a bilateral treatment is performed, to eliminate the risks of overdose with local anesthesia and with the aim of improving the comfort of the patient.

Notch3-regulated microRNAs impair CXCR4-dependent maturation of thymocytes allowing maintenance and progression of T-ALL.

Malignant transformation of T-cell progenitors causes T-cell acute lymphoblastic leukemia (T-ALL), an aggressive childhood lymphoproliferative disorder. Activating mutations of Notch, Notch1 and Notch3, have been detected in T-ALL patients. In this study, we aimed to deeply characterize hyperactive Notch3-related pathways involved in T-cell dynamics within the thymus and bone marrow to propose these processes as an important step in facilitating the progression of T-ALL. We previously generated a transgenic T-ALL mouse model (N3-ICtg) demonstrating that aberrant Notch3 signaling affects early thymocyte maturation programs and leads to bone marrow infiltration by CD4+CD8+ (DP) T cells that are notably, Notch3highCXCR4high. Newly, our in vivo results suggest that an anomalous immature thymocyte subpopulation, such as CD4-CD8- (DN) over-expressing CD3ɛ, but with low CXCR4 expression, dominates N3-ICtg thymus-resident DN subset in T-ALL progression. MicroRNAs might be of significance in T-ALL pathobiology, however, whether required for leukemia maintenance is not fully understood. The selection of specific DN subsets demonstrates the inverse correlation between CXCR4 expression and a panel of Notch3-deregulated miRNAs. Interestingly, we found that within DN thymocyte subset hyperactive Notch3 inhibits CXCR4 expression through the cooperative effects of miR-139-5p and miR-150-5p, thus impinging on thymocyte differentiation with accumulation of DNCD3ɛ+CXCR4- cells. These data point out that deregulation of Notch3 in T-ALL, besides its role in sustaining dissemination of abnormal DP T cells, as we previously demonstrated, could play a role in selecting specific DN immature T cells within the thymus, thus impeding T cell development, to facilitate T-ALL progression inside the bone marrow.

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 α(4) integrin plays a pivotal role in the maintenance of NK cells in the BM sinusoids and that α(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-γ 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.

Non-covalent synthesis of metal oxide nanoparticle-heparin hybrid systems: a new approach to bioactive nanoparticles.

Heparin has been conjugated to Fe3O4, Co3O4, and NiO nanoparticles (NPs) through electrostatic interactions, producing colloidal suspensions of hybrid metal oxide heparin NPs that are stable in water. Negative zeta potentials and retention of heparin's ability to capture toluidine blue indicate that heparin's negative charges are exposed on the surface of the coated NPs. IR results confirmed the formation of nanohybrids as did NMR experiments, which were also interpreted on the basis of toluidine blue tests. Transmission electron microscopy results revealed that the heparin coating does not modify the shape or dimension of the NPs. Dynamic light scattering and negative zeta potential measurements confirmed that heparin surface functionalisation is an effective strategy to prevent NP aggregation.