POS0057 INDUCIBLE REGULATORY SYNOVIAL MACROPHAGES: A PROOF-OF-CONCEPT STUDY FOR A CELL-BASED TARGETED THERAPY FOR RHEUMATOID ARTHRITIS

Background

Infiltration of monocyte-derived macrophages into the synovial tissue (ST) is a hallmark of rheumatoid arthritis (RA) pathology. These macrophages promote inflammation, local joint effusion, and joint damage via the release of cytokines, oxygen reactive species, and tissue damaging enzymes. However, balancing these, are the ‘regulatory’ macrophages with inflammation-resolving properties, characterised by expression of CD206 and MerTK, dominant within the ST of healthy individuals as well as RA patients in remission (1). Indeed, these cells are believed to actively contribute to the maintenance of remission.

Macrophages are known to exhibit remarkable phenotypic plasticity and understanding the role of this characteristic in regulating inflammation and pathology remains a major challenge, as does the characterization of factors in the microenvironment such as the synovium that control such macrophage characteristics. Importantly, whether the infiltrating, inflammatory macrophages of the RA ST similarly exhibit such phenotypic plasticity, and whether this occurs during the process of reaching remission, remains to be studied.

Objectives

We investigated the phenotypic plasticity of inflammatory synovial macrophages from patients with RA in vitro, investigating their ability to convert from an inflammatory macrophage population into ‘regulatory’ CD206+MerTK+ macrophages. These findings will provide a proof-of-concept as to the utility of these macrophage for a cell-based therapy in resolving inflammation in patients with RA, and will likely extend our understanding of the mechanisms of action of currently used therapeutics.

Methods

Synovial fluid (SF) mononuclear cells were obtained from patients with active early RA (<1 year; fulfilling 2010 ACR/EULAR classification criteria). Cryopreserved SFMCs were cultured for 48hr in the presence of 10 ng/mL interferon(IFN)γ, 50 ng/mL dexamethasone, 10 μg/mL Infliximab, or diluent. Following culture, cells were immunostained and analysed using a Beckman Coulter CytoFLEX flow cytometer and FlowJo software. SF macrophages were characterised by expression of CD14, CD45, CD68 (Figure 1A), and proportions of CD206+ MerTK+ macrophages measured.

Figure 1.

Synovial fluid CD68+macrophage plasticity in vitro. (A) Gating strategy depicting CD68+ CD45+CD14+ SF macrophage determination. (B) Proportions of CD206 and MerTK-expressing SF macrophages after 48hr culture in the presence of 10 ng/mL IFNγ, 50 ng/mL dexamethasone or 10 µg/mL Infliximab, or absence. Data are representative of 5 individual experiments. Data were analysed by two-way ANOVA followed by Dunnett’s multiple comparison test, *p<0.05.

Results

Prior to culture, the CD68+ macrophage populations present in SF were found to be predominantly CD206-MerTK-. After 48 hours of culture, in the absence of any stimulus, there was an increase in proportions of CD206+MerTK+ macrophages. Treatment with either dexamethasone or anti-TNF (Infliximab) resulted in a further increase in proportions of CD206+ MerTK+, M2-like macrophages. In contrast, culture with IFNγ induced a reduction in this population. Importantly, we found that the generated CD206+MerTK+ macrophages were phenotypically stable in culture following removal of these differentiating agents.

Conclusion

Our findings demonstrate that inflammatory SF cells are indeed able to polarise to regulatory, CD206+MerTK+ macrophages in vitro. The findings provide further mechanistic insights into the basis for the therapeutic benefits of glucocorticoids and TNF inhibitors, as well as providing initial proof-of-concept in the use of regulatory macrophages as a cellular-based therapy or therapeutic target for patients with RA.

References

[1]Alivernini S, MacDonald L, Elmesmari A, et al., Distinct synovial tissue macrophage subsets regulate inflammation and remission in rheumatoid arthritis. Nature Medicine. 2020;26(8):1295-306 10.1038/s41591-020-0939-8.

Disclosure of Interests

None declared

Myelin Defects in Niemann-Pick Type C Disease: Mechanisms and Possible Therapeutic Perspectives

Niemann–Pick type C (NPC) disease is a wide-spectrum clinical condition classified as a neurovisceral disorder affecting mainly the liver and the brain. It is caused by mutations in one of two genes, NPC1 and NPC2, coding for proteins located in the lysosomes. NPC proteins are deputed to transport cholesterol within lysosomes or between late endosome/lysosome systems and other cellular compartments, such as the endoplasmic reticulum and plasma membrane. The first trait of NPC is the accumulation of unesterified cholesterol and other lipids, like sphingosine and glycosphingolipids, in the late endosomal and lysosomal compartments, which causes the blockade of autophagic flux and the impairment of mitochondrial functions. In the brain, the main consequences of NPC are cerebellar neurodegeneration, neuroinflammation, and myelin defects. This review will focus on myelin defects and the pivotal importance of cholesterol for myelination and will offer an overview of the molecular targets and the pharmacological strategies so far proposed, or an object of clinical trials for NPC. Finally, it will summarize recent data on a new and promising pharmacological perspective involving A_2A adenosine receptor stimulation in genetic and pharmacological NPC dysmyelination models.

Insight into the Role of the STriatal-Enriched Protein Tyrosine Phosphatase (STEP) in A2A Receptor-Mediated Effects in the Central Nervous System

The STriatal-Enriched protein tyrosine phosphatase STEP is a brain-specific tyrosine phosphatase that plays a pivotal role in the mechanisms of learning and memory, and it has been demonstrated to be involved in several neuropsychiatric diseases. Recently, we found a functional interaction between STEP and adenosine A_2A receptor (A_2AR), a subtype of the adenosine receptor family widely expressed in the central nervous system, where it regulates motor behavior and cognition, and plays a role in cell survival and neurodegeneration. Specifically, we demonstrated the involvement of STEP in A_2AR-mediated cocaine effects in the striatum and, more recently, we found that in the rat striatum and hippocampus, as well as in a neuroblastoma cell line, the overexpression of the A_2AR, or its stimulation, results in an increase in STEP activity. In the present article we will discuss the functional implication of this interaction, trying to examine the possible mechanisms involved in this relation between STEP and A_2ARs.

Longitudinal Flow Decorrelations in Xe+Xe Collisions at sqrt[s_{NN}]=5.44 TeV with the ATLAS Detector

The first measurement of longitudinal decorrelations of harmonic flow amplitudes v_{n} for n=2-4 in Xe+Xe collisions at sqrt[s_{NN}]=5.44  TeV is obtained using 3  μb^{-1} of data with the ATLAS detector at the LHC. The decorrelation signal for v_{3} and v_{4} is found to be nearly independent of collision centrality and transverse momentum (p_{T}) requirements on final-state particles, but for v_{2} a strong centrality and p_{T} dependence is seen. When compared with the results from Pb+Pb collisions at sqrt[s_{NN}]=5.02  TeV, the longitudinal decorrelation signal in midcentral Xe+Xe collisions is found to be larger for v_{2}, but smaller for v_{3}. Current hydrodynamic models reproduce the ratios of the v_{n} measured in Xe+Xe collisions to those in Pb+Pb collisions but fail to describe the magnitudes and trends of the ratios of longitudinal flow decorrelations between Xe+Xe and Pb+Pb. The results on the system-size dependence provide new insights and an important lever arm to separate effects of the longitudinal structure of the initial state from other early and late time effects in heavy-ion collisions.

Search for Heavy Resonances Decaying into a Photon and a Hadronically Decaying Higgs Boson in pp Collisions at sqrt[s]=13 TeV with the ATLAS Detector

This Letter presents a search for the production of new heavy resonances decaying into a Higgs boson and a photon using proton-proton collision data at sqrt[s]=13  TeV collected by the ATLAS detector at the LHC. The data correspond to an integrated luminosity of 139  fb^{-1}. The analysis is performed by reconstructing hadronically decaying Higgs boson (H→bb[over ¯]) candidates as single large-radius jets. A novel algorithm using information about the jet constituents in the center-of-mass frame of the jet is implemented to identify the two b quarks in the single jet. No significant excess of events is observed above the expected background. Upper limits are set on the production cross-section times branching fraction for narrow spin-1 resonances decaying into a Higgs boson and a photon in the resonance mass range from 0.7 to 4 TeV, cross-section times branching fractions are excluded between 11.6 fb and 0.11 fb at a 95% confidence level.

Search for Higgs Boson Decays into a Z Boson and a Light Hadronically Decaying Resonance Using 13 TeV pp Collision Data from the ATLAS Detector

A search for Higgs boson decays into a Z boson and a light resonance in two-lepton plus jet events is performed, using a pp collision dataset with an integrated luminosity of 139  fb^{-1} collected at sqrt[s]=13  TeV by the ATLAS experiment at the CERN LHC. The resonance considered is a light boson with a mass below 4 GeV from a possible extended scalar sector or a charmonium state. Multivariate discriminants are used for the event selection and for evaluating the mass of the light resonance. No excess of events above the expected background is found. Observed (expected) 95% confidence-level upper limits are set on the Higgs boson production cross section times branching fraction to a Z boson and the signal resonance, with values in the range 17-340 pb (16_{-5}^{+6}-320_{-90}^{+130}  pb) for the different light spin-0 boson mass and branching fraction hypotheses, and with values of 110 and 100 pb (100_{-30}^{+40} and 100_{-30}^{+40}  pb) for the η_{c} and J/ψ hypotheses, respectively.

Incidence and delay of atrial tachycardia after patent foramen ovale closure

Background

In the large randomized trials evaluating patent foramen ovale (PFO) closure vs. medical treatment in secondary prevention of stroke, the incidence of atrial fibrillation has been reported more frequently with PFO closure (2.9–6.6%) than with medical treatment (0.4–1.9%). These episodes were clinically reported and may not reflect the real incidence detected by prolonged ECG recording.

Purpose

To evaluate the incidence and timing of supraventricular tachycardia (SVT) after percutaneous PFO closure.

Methods

Prolonged cardiac monitoring was proposed to patients undergoing PFO closure at the tertiary center of Pitié Salpétrière Hospital, Paris. According to the estimated risk of SVT, two different approaches were used to monitor cardiac rhythm. A 3-year permanent recording using REVEAL™ XT or LINQ was proposed to high risk patients (age &gt;45 years, multiple CV risk factors, prior palpitations or supraventricular ectopic activity during Holter monitoring prior to the intervention). A 4-week, 15-lead ECG continuous recording using the patch-free, wire-free, wearable Cardioskin™ system was proposed to lower risk patients. Endpoints of interest were the occurrence of SVT episodes (&gt;30 seconds) and unplanned medical consultation or hospitalization for this reason

Results

From October 2018 to January 2020, a total of 64 patients underwent prolonged ECG monitoring including 32 (50.0%) and 32 (50.0%) patients with Cardioskin™ and REVEAL™ systems, respectively. A SVT was recorded in 11 (17.4%) patients, including atrial fibrillation (AF) in 6 (9.5%) patients. The median delay of SVT occurrence was 33.0 (14.0–39) days after the procedure (Figure 1) and 18 (10.8–34.8) days for the 6 patients with AF. Unplanned hospitalization or emergency medical visit for symptomatic SVT occurred in 5 (45.5%) patients. Antiarrhythmic medication and oral anticoagulation were initiated in 10 (90.1%) and 7 (63.6%) of the 11 patients, respectively, and SVT recurrences were recorded in 5 (45.5%) patients. No stroke was reported in any of the 11 patients during follow-up. There were no significant differences with respect to baseline and procedural characteristics among patients with or without SVT during follow-up.

Conclusion

Atrial tachycardia is frequent (17.4%) after PFO closure and long-term continuous ECG recording suggests that the incidence is higher than the clinical episodes reported in the randomized trials. This arrhythmic complication of PFO closure seems limited to the first 4 months following the procedure. Larger studies need now to confirm our findings.

Figure 1

Funding Acknowledgement

Type of funding source: Public Institution(s). Main funding source(s): ACTION coeur

Dijet Resonance Search with Weak Supervision Using sqrt[s]=13 TeV pp Collisions in the ATLAS Detector

This Letter describes a search for narrowly resonant new physics using a machine-learning anomaly detection procedure that does not rely on signal simulations for developing the analysis selection. Weakly supervised learning is used to train classifiers directly on data to enhance potential signals. The targeted topology is dijet events and the features used for machine learning are the masses of the two jets. The resulting analysis is essentially a three-dimensional search A→BC, for m_{A}∼O(TeV), m_{B},m_{C}∼O(100  GeV) and B, C are reconstructed as large-radius jets, without paying a penalty associated with a large trials factor in the scan of the masses of the two jets. The full run 2 sqrt[s]=13  TeV pp collision dataset of 139  fb^{-1} recorded by the ATLAS detector at the Large Hadron Collider is used for the search. There is no significant evidence of a localized excess in the dijet invariant mass spectrum between 1.8 and 8.2 TeV. Cross-section limits for narrow-width A, B, and C particles vary with m_{A}, m_{B}, and m_{C}. For example, when m_{A}=3  TeV and m_{B}≳200  GeV, a production cross section between 1 and 5 fb is excluded at 95% confidence level, depending on m_{C}. For certain masses, these limits are up to 10 times more sensitive than those obtained by the inclusive dijet search. These results are complementary to the dedicated searches for the case that B and C are standard model bosons.

CP Properties of Higgs Boson Interactions with Top Quarks in the tt[over ¯]H and tH Processes Using H→γγ with the ATLAS Detector

A study of the charge conjugation and parity (CP) properties of the interaction between the Higgs boson and top quarks is presented. Higgs bosons are identified via the diphoton decay channel (H→γγ), and their production in association with a top quark pair (tt[over ¯]H) or single top quark (tH) is studied. The analysis uses 139  fb^{-1} of proton-proton collision data recorded at a center-of-mass energy of sqrt[s]=13  TeV with the ATLAS detector at the Large Hadron Collider. Assuming a CP-even coupling, the tt[over ¯]H process is observed with a significance of 5.2 standard deviations. The measured cross section times H→γγ branching ratio is 1.64_{-0.36}^{+0.38}(stat)_{-0.14}^{+0.17}(sys)  fb, and the measured rate for tt[over ¯]H is 1.43_{-0.31}^{+0.33}(stat)_{-0.15}^{+0.21}(sys) times the Standard Model expectation. The tH production process is not observed and an upper limit on its rate of 12 times the Standard Model expectation is set. A CP-mixing angle greater (less) than 43 (-43)° is excluded at 95% confidence level.

Search for Heavy Higgs Bosons Decaying into Two Tau Leptons with the ATLAS Detector Using pp Collisions at sqrt[s]=13 TeV

A search for heavy neutral Higgs bosons is performed using the LHC Run 2 data, corresponding to an integrated luminosity of 139  fb^{-1} of proton-proton collisions at sqrt[s]=13  TeV recorded with the ATLAS detector. The search for heavy resonances is performed over the mass range 0.2-2.5 TeV for the τ^{+}τ^{-} decay with at least one τ-lepton decaying into final states with hadrons. The data are in good agreement with the background prediction of the standard model. In the M_{h}^{125} scenario of the minimal supersymmetric standard model, values of tanβ>8 and tanβ>21 are excluded at the 95% confidence level for neutral Higgs boson masses of 1.0 and 1.5 TeV, respectively, where tanβ is the ratio of the vacuum expectation values of the two Higgs doublets.

Measurement of the Lund Jet Plane Using Charged Particles in 13 TeV Proton-Proton Collisions with the ATLAS Detector

The prevalence of hadronic jets at the LHC requires that a deep understanding of jet formation and structure is achieved in order to reach the highest levels of experimental and theoretical precision. There have been many measurements of jet substructure at the LHC and previous colliders, but the targeted observables mix physical effects from various origins. Based on a recent proposal to factorize physical effects, this Letter presents a double-differential cross-section measurement of the Lund jet plane using 139  fb^{-1} of sqrt[s]=13  TeV proton-proton collision data collected with the ATLAS detector using jets with transverse momentum above 675 GeV. The measurement uses charged particles to achieve a fine angular resolution and is corrected for acceptance and detector effects. Several parton shower Monte Carlo models are compared with the data. No single model is found to be in agreement with the measured data across the entire plane.

Population Data Centre Profiles: Centre for Data Linkage

The Centre for Data Linkage (CDL) was established at Curtin University, Western Australia, to develop infrastructure to enable cross-jurisdictional record linkage in Australia. The CDL’s operating model makes use of the ‘separation principle’, with content data typically provided to researchers directly by the data custodian; jurisdictional linkage where available are used within the linkage process. Along with conducting record linkage, the team has also invested in establishing a research programme in record linkage methodology and in developing modern record linkage software which can handle the size and complexity of today’s workloads. The Centre has been instrumental in the development of practical methods for privacy-preserving record linkage, with this methodology now regularly used for real-world linkages. While the promise of a nation-wide linkage system in Australia has yet to be met, distributed models provide a potential solution.

Measurement of Azimuthal Anisotropy of Muons from Charm and Bottom Hadrons in pp Collisions at sqrt[s]=13 TeV with the ATLAS Detector

The elliptic flow of muons from the decay of charm and bottom hadrons is measured in pp collisions at sqrt[s]=13  TeV using a data sample with an integrated luminosity of 150  pb^{-1} recorded by the ATLAS detector at the LHC. The muons from heavy-flavor decay are separated from light-hadron decay muons using momentum imbalance between the tracking and muon spectrometers. The heavy-flavor decay muons are further separated into those from charm decay and those from bottom decay using the distance-of-closest-approach to the collision vertex. The measurement is performed for muons in the transverse momentum range 4-7 GeV and pseudorapidity range |η|<2.4. A significant nonzero elliptic anisotropy coefficient v_{2} is observed for muons from charm decays, while the v_{2} value for muons from bottom decays is consistent with zero within uncertainties.

Search for Magnetic Monopoles and Stable High-Electric-Charge Objects in 13 Tev Proton-Proton Collisions with the ATLAS Detector

A search for magnetic monopoles and high-electric-charge objects is presented using 34.4  fb^{-1} of 13 TeV pp collision data collected by the ATLAS detector at the LHC during 2015 and 2016. The considered signature is based upon high ionization in the transition radiation tracker of the inner detector associated with a pencil-shape energy deposit in the electromagnetic calorimeter. The data were collected by a dedicated trigger based on the tracker high-threshold hit capability. The results are interpreted in models of Drell-Yan pair production of stable particles with two spin hypotheses (0 and 1/2) and masses ranging from 200 to 4000 GeV. The search improves by approximately a factor of 5 the constraints on the direct production of magnetic monopoles carrying one or two Dirac magnetic charges and stable objects with electric charge in the range 20≤|z|≤60 and extends the charge range to 60<|z|≤100.

Observation of Light-by-Light Scattering in Ultraperipheral Pb+Pb Collisions with the ATLAS Detector

This Letter describes the observation of the light-by-light scattering process, γγ→γγ, in Pb+Pb collisions at sqrt[s_{NN}]=5.02  TeV. The analysis is conducted using a data sample corresponding to an integrated luminosity of 1.73  nb^{-1}, collected in November 2018 by the ATLAS experiment at the LHC. Light-by-light scattering candidates are selected in events with two photons produced exclusively, each with transverse energy E_{T}^{γ}>3  GeV and pseudorapidity |η_{γ}|<2.4, diphoton invariant mass above 6 GeV, and small diphoton transverse momentum and acoplanarity. After applying all selection criteria, 59 candidate events are observed for a background expectation of 12±3 events. The observed excess of events over the expected background has a significance of 8.2 standard deviations. The measured fiducial cross section is 78±13(stat)±7(syst)±3(lumi)  nb.

Adenosine A2A receptor stimulation restores cell functions and differentiation in Niemann-Pick type C-like oligodendrocytes

Niemann Pick type C (NPC) disease is a rare neurovisceral disorder. Mutations in npc1 gene induce an intracellular accumulation of unesterified cholesterol in the endosomal/lysosomal system causing cell death. We recently showed that stimulation of adenosine A_2A receptors (A_2AR) restores cholesterol accumulation in late endosomes/lysosomes in human NPC fibroblasts and neural cell lines transiently transfected with NPC1 siRNA, suggesting that these receptors might be targeted to contrast the disease. Since NPC1 disease is characterized by dysmyelination and maturational arrest of oligodendrocyte progenitors (OPs), in this study, we investigated whether A_2AR stimulation could promote oligodendrocyte differentiation and myelin formation, thus overcoming these important neurological abnormalities. We developed a NPC1 pharmacological model, in which primary cultures of OPs are exposed to a cholesterol transport inhibitor to induce a NPC1-like phenotype characterized by several typical features such as (i) cholesterol accumulation, (ii) altered mitochondrial morphology and membrane potential, (iii) defect of autophagy and (iv) maturation arrest. The A_2AR agonist CGS21680 normalized all NPC1-like features. The ability of CGS21680 of rescuing OP from maturational arrest and promoting their differentiation to mature OL, suggests that A_2AR stimulation might be exploited to correct dysmyelination in NPC1, further supporting their therapeutic potential in the disease.

Neuroprotective potential of adenosine A1 receptor partial agonists in experimental models of cerebral ischemia

Cerebral ischemia is the second most common cause of death and a major cause of disability worldwide. Available therapies are based only on anticoagulants or recombinant tissue plasminogen activator. Extracellular adenosine increases during ischemia and acts as a neuroprotective endogenous agent mainly by activating adenosine A₁ receptors (A₁ Rs) which control calcium influx, glutamate release, membrane potential, and metabolism. Accordingly, in many experimental paradigms it has been already demonstrated that the stimulation of A₁ R with full agonists is able to reduce ischemia-related structural and functional brain damage; unfortunately, cardiovascular side effects and desensitization of A₁ R induced by these compounds have strongly limited their exploitation in stroke therapy so far. Among the newly emerging compounds, A₁ R partial agonists could be almost free of side effects and equally effective. Therefore, we decided to evaluate the neuroprotective potential of two A₁ R partial agonists, namely 2'-dCCPA and 3'-dCCPA, in in vitro and ex vivo experimental models of cerebral ischemia. Within the experimental paradigm of oxygen-glucose deprivation in vitro in human neuroblastoma (SH-SY5Y) cells both A₁ R partial agonists increased cell viability. Considering the high level of expression of A₁ Rs in the hippocampus and the susceptibility of CA1 region to hypoxia, we performed electrophysiological experiments in this subfield. The application of 7 min of oxygen-glucose deprivation constantly produces an irreversible synaptic failure in all the C57Bl/6 mice hippocampal slices evaluated; both tested compounds allowed a significant recovery of synaptic transmission. These findings demonstrate that A₁ R and its partial agonists are still of interest for cerebral ischemia therapy. OPEN SCIENCE BADGES: This article has received a badge for *Open Materials* because it provided all relevant information to reproduce the study in the manuscript. The complete Open Science Disclosure form for this article can be found at the end of the article. More information about the Open Practices badges can be found at https://cos.io/our-services/open-science-badges/.

Histopathology of the gut in rheumatic diseases

The gastrointestinal tract regulates the trafficking of macromolecules between the environment and the host through an epithelial barrier mechanism and is an important part of the immune system controlling the equilibrium between tolerance and immunity to non-self-antigens. Various evidence indicates that intestinal inflammation occurs in patients with rheumatic diseases. In many rheumatic diseases intestinal inflammation appears to be linked to dysbiosis and possibly represents the common denominator in the pathogenesis of different rheumatic diseases. The continuative interaction between dysbiosis and the intestinal immune system may lead to the aberrant activation of immune cells that can re-circulate from the gut to the sites of extraintestinal inflammation as observed in patients with ankylosing spondylitis. The exact contribution of genetic factors in the development of intestinal inflammation in rheumatic diseases needs to be clarified.

Pathogenesis of polymyalgia rheumatica

Polymyalgia rheumatica (PMR) is a chronic, inflammatory disorder of unknown cause, almost exclusively occurring in people aged over 50 and often associated with giant cell arteritis. The evidence that PMR occurs almost exclusively in individuals aged over 50 may indicate that age-related immune alterations in genetically predisposed subjects contribute to development of the disease. Several infectious agents have been investigated as possible triggers of PMR even though the results are inconclusive. Activation of the innate and adaptive immune systems has been proved in PMR patients as demonstrated by the activation of dendritic cells and monocytes/macrophages and the altered balance between Th17 and Treg cells. Disturbed B cell distribution and function have been also demonstrated in PMR patients suggesting a pathogenesis more complex than previously imagined. In this review we will discuss the recent findings regarding the pathogenesis of PMR.

The adenosine A2A receptor agonist T1-11 ameliorates neurovisceral symptoms and extends the lifespan of a mouse model of Niemann-Pick type C disease

Niemann-Pick C is a fatal neurovisceral disorder caused, in 95% of cases, by mutation of NPC1 gene. Therapeutic options are extremely limited and new "druggable" targets are highly warranted. We previously demonstrated that the stimulation of the adenosine A_2A receptor (A_2AR) normalized the pathological phenotype of cellular models of NPC1. Since the validation of A_2ARs as a therapeutic target for NPC1 can be obtained only conducting studies in in vivo models of the disease, in the present paper, the effects of two agonists of A_2ARs were evaluated in the mouse model Balb/c Npc1^nih, hereafter indicated as NPC1-/-. The agonists CGS21680 (2.5 and 5mg/kg/day by intraperitoneal injection) and T1-11 (50mg/kg/day in drinking water) were administered at a presymptomatic stage of the disease of NPC1-/- mice (PN28 and PN30, respectively); the experimental groups were the following: vehicle-treated WT mice (N=16 for both CGS and T1-11 treatments); vehicle-treated NPC1-/- mice (N=14 for CGS and 12 for T1-11 treatment); CGS-treated NPC1-/- mice (N=7) and T1-11-treated NPC1-/- mice (N=11). The efficacy of the treatments was evaluated by comparing vehicle-treated and CGS or T1-11-treated NPC1-/- mice for their motor deficits (analyzed by both rotarod and footprint tests), hippocampal cognitive impairment (by Novel Object Recognition (NOR) test), cerebellar neurodegeneration (Purkinje neurons counting), and cholesterol and sphingomyelin accumulation in spleen and liver. Finally, the effect of both agonists on survival was evaluated by applying a humane late endpoint (weight loss >30% of peak weight, punched posture and reduced activity in the cage). The results demonstrated that, while CGS21680 only slightly attenuated cognitive deficits, T1-11 ameliorated motor coordination, significantly improved cognitive impairments, increased the survival of Purkinje neurons and reduced sphingomyelin accumulation in the liver. More importantly, it significantly prolonged the lifespan of NPC1-/- mice. In vitro experiments conducted in a neuronal model of NPC1 demonstrated that the ability of T1-11 to normalize cell phenotype was mediated by the selective activation of A_2ARs and modulation of intracellular calcium levels. In conclusion, our results fully confirm the validity of A_2ARs as a new target for NPC1 treatment. As soon as new ligands with improved pharmacokinetic characteristics (i.e. orally active, with brain bioavailability and metabolic stability) will be obtained, A_2AR agonists could represent a breakthrough in the treatment of NPC.

Interleukin-9 and T helper type 9 cells in rheumatic diseases

Interleukin (IL)-9 is a 28-30 kDa monomeric glycosylated polypeptide belonging to the IL-7/IL-9 family of proteins that bind to a composite receptor consisting of the private receptor IL-9R and the IL-2 receptor, gamma (IL-2RG), a common gamma subunit shared by the receptors of many different cytokines. The IL-9R is expressed widely and IL-9 impacts a number of effector cells, such as effector T cells, B cells, innate lymphoid cells, mast cells, polymorphonuclear cells, epithelial cells and smooth muscle cells, playing an important role in regulating inflammatory immunity. The critical role of IL-9 in promoting cellular and humoral immune responses makes it an important focus of potential therapeutic interventions. Recently, a defined subset of T helper type cells, Th9 cells, has been identified by the potent production of IL-9. The involvement of the Th9 cell subset has been described in many types of inflammatory diseases, namely atopic diseases, helminth infections, experimental autoimmune encephalomyelitis and ulcerative colitis. In this review, we summarize the IL-9 biological activities, highlighting roles for IL-9 and Th9 cells in rheumatoid and psoriatic arthritis, systemic vasculitis, systemic lupus erythematosus and systemic sclerosis.

Interleukin (IL)-9/IL-9R axis drives γδ T cells activation in psoriatic arthritis patients

Cytokines such as tumour necrosis factor (TNF)-α, interleukin (IL)-12, interferon (IFN)-γ, IL-23 and, more recently, IL-9, have been implicated in the initiation/maintenance of inflammation in psoriasis and psoriatic arthritis (PsA). In the present study we aimed to characterize the role of γδ T cells in peripheral blood and synovial fluid of PsA patients and to investigate their response to in-vitro stimulation with antigen or cytokines (IL-9 and IL-23). γδ T cells isolated from peripheral blood mononuclear cells and synovial fluid were analysed by flow cytometry to evaluate the phenotype and cytokine production. IL-23R and IL-9R gene expression were also evaluated by reverse transcription-polymerase chain reaction (RT-PCR). Peripheral blood mononuclear cells (PBMC), sorted γδ T cells and γδ cell lines were also stimulated in vitro with isopentenyl pyrophosphate (IPP), recombinant IL-9 or recombinant IL-23. Our results show an expansion of γδ T cells with a predominant effector memory phenotype in peripheral blood and synovium of untreated PsA patients, which reverses significantly after treatment with anti-TNF-α or anti-IL-12/IL-23R monoclonal antibodies (mAbs). Moreover, in PsA patients γδ T cells activation is driven prevalently by IL-9/IL-9R interaction, and not only by IL-23/IL-23R. Together these findings indicate γδ T cells and IL-9 as new players in the pathogenesis of PsA.

IVIG in APS pregnancy

For more than two decades, the intravenous administration of high doses of IgG pooled from the plasma of healthy donors (immune globulin therapy, also known as ‘IVIG’) has benefited patients with a variety of autoimmune disorders. A potential therapeutic role of IVIG in the prevention of thrombosis and of miscarriages in antiphospholipid syndrome (APS) has been postulated. Multicenter randomized controlled trials attempted to define the role of IVIG in preventing pregnancy complications in APS indicate that simple anticoagulation could not be completely satisfactory, and certain patient subgroups might take advantage of IVIG therapy alone or in combination with heparin.

Stimulation of adenosine A2A receptors reduces intracellular cholesterol accumulation and rescues mitochondrial abnormalities in human neural cell models of Niemann-Pick C1

Niemann Pick C 1 (NPC1) disease is an incurable, devastating lysosomal-lipid storage disorder characterized by hepatosplenomegaly, progressive neurological impairment and early death. Current treatments are very limited and the research of new therapeutic targets is thus mandatory. We recently showed that the stimulation of adenosine A2A receptors (A2ARs) rescues the abnormal phenotype of fibroblasts from NPC1 patients suggesting that A2AR agonists could represent a therapeutic option for this disease. However, since all NPC1 patients develop severe neurological symptoms which can be ascribed to the complex pathology occurring in both neurons and oligodendrocytes, in the present paper we tested the effects of the A2AR agonist CGS21680 in human neuronal and oligodendroglial NPC1 cell lines (i.e. neuroblastoma SH-SY5Y and oligodendroglial MO3.13 transiently transfected with NPC1 small interfering RNA). The down-regulation of the NPC1 protein effectively resulted in intracellular cholesterol accumulation and altered mitochondrial membrane potential. Both effects were significantly attenuated by CGS21680 (500 nM). The protective effects of CGS were prevented by the selective A2AR antagonist ZM241385 (500 nM). The involvement of calcium modulation was demonstrated by the ability of Bapta-AM (5-7 μM) in reverting the effect of CGS. The A2A-dependent activity was prevented by the PKA-inhibitor KT5720, thus showing the involvement of the cAMP/PKA signaling. These findings provide a clear in vitro proof of concept that A2AR agonists are promising potential drugs for NPC disease.

Striatal adenosine-cannabinoid receptor interactions in rats over-expressing adenosine A2A receptors

Adenosine A2A receptors (A2 A Rs) and cannabinoid CB1 receptors (CB1 Rs) are highly expressed in the striatum, where they functionally interact and form A2A /CB1 heteroreceptor complexes. We investigated the effects of CB1 R stimulation in a transgenic rat strain over-expressing A2 A Rs under the control of the neural-specific enolase promoter (NSEA2A rats) and in age-matched wild-type (WT) animals. The effects of the CB1 R agonist WIN 55,212-2 (WIN) were significantly lower in NSEA2A rats than in WT animals, as demonstrated by i) electrophysiological recordings of synaptic transmission in corticostriatal slices; ii) the measurement of glutamate outflow from striatal synaptosomes and iii) in vivo experiments on locomotor activity. Moreover, while the effects of WIN were modulated by both A2 A R agonist (CGS 21680) and antagonists (ZM 241385, KW-6002 and SCH-442416) in WT animals, the A2 A R antagonists failed to influence WIN-mediated effects in NSEA2A rats. The present results demonstrate that in rats with genetic neuronal over-expression of A2 A Rs, the effects mediated by CB1 R activation in the striatum are significantly reduced, suggesting a change in the stoichiometry of A2A and CB1 receptors and providing a strategy to dissect the involvement of A2 A R forming or not forming heteromers in the modulation of striatal functions. These findings add additional evidence for the existence of an interaction between striatal A2 A Rs and CB1 Rs, playing a fundamental role in the regulation of striatal functions. We studied A2A -CB1 receptor interaction in transgenic rats over-expressing adenosine A2A receptors under the control of the neuron-specific enolase promoter (NSEA2A ). In these rats, we demonstrated a reduced effect of the CB1 receptor agonist WIN 55,212-2 in the modulation of corticostriatal synaptic transmission and locomotor activity, while CB1 receptor expression level did not change with respect to WT rats. A reduction in the expression of A2A -CB1 receptor heteromers is postulated.

[Finger or thumb sucking. New interpretations and therapeutic implications]

AIM

Finger sucking is frequently found in children and sometimes in adults too. Often reasons are found to explain why certain children feel the need to suck their thumbs or fingers, but these explanations are always derived from clinical observation without any rational support, searching for motives for this bad habit from family life; strict parents, jealousy at the birth of a sibling, difficulty accepting the end of breastfeeding etc. Some think that a child should continue to suck after actual nutrition has ended and the substitution of the mother's nipple with a thumb or finger could fill this need. Research however, using anatomical and neurophysiological data, explains why an infant forms the habit of thumb sucking from a neurological standpoint abandoning the psychological explanations proposed until now.

METHODS

Forty thumb-sucking subjects with ages ranging from 5 to 25 years and a control group of 20 non-thumb-sucking subjects with correct swallowing patterns were analyzed evaluating postural and neurological effects of thumb sucking. Instruments used for this evaluation were a device for electromyography to measure the muscular tone and a baropodometer, stabilometer and a scoliosometer to analyse posture.

RESULTS

Analyzed subjects had an evident improvement at the baropodometer and stabilometer and a scoliosometer examination to analyze posture and at the electromyography analysis.

CONCLUSION

The results obtained confirm that a thumb-sucking subject puts the thumb in the mouth to stimulate the nasal-palatal receptors of trigeminus and obtain muscular balance and a release of physical and psychological tension.

Arterial stiffness indexes and serum cytokine levels in seronegative spondyloarthritis: relationships between stiffness markers and metabolic and immunoinflammatory variables

OBJECTIVE

The aim of this study was to investigate the relationship between immunoinflammatory markers and indexes of arterial stiffness in patients with seronegative spondyloarthritis (SpA).

METHOD

We enrolled consecutive patients with inflammatory seronegative SpA referred to a rheumatology outpatient clinic. Control subjects were patients admitted in the same period for any cause other than chronic inflammatory disease or acute cardiovascular and cerebrovascular events. Carotid-femoral pulse wave velocity (PWV) was measured and the aortic pressure waveform was used to calculate the augmentation index (Aix). We also evaluated plasma levels of C-reactive protein (CRP), interleukin (IL)-1β, tumour necrosis factor (TNF)-α, and interleukin (IL)-6 as markers of immunoinflammatory activation.

RESULTS

This study enrolled 53 patients with SpA and 55 control subjects. After adjustment for blood glucose, cholesterol, and triglyceride levels, and systolic (SBP) and diastolic blood pressure (DBP), patients with seronegative SpA showed higher mean PWV and Aix compared to controls. Moreover, in patients with seronegative SpA, we observed higher mean plasma levels of IL-6, IL-1β, and TNF-α in subjects with mean PWV > 8 m/s in comparison with those with PWV < 8 m/s. Multivariate analysis revealed a significant association between PWV > 8 m/s and male gender, age, diabetes, hypertension, low density lipoprotein cholesterol (LDL-C) > 120 mg/dL, total cholesterol (TC) > 200 mg/dL, coronary artery disease (CAD), microalbuminuria, carotid plaque, and plasma levels of IL-6, IL-1β, and TNF-α.

CONCLUSIONS

These findings emphasize the role of inflammatory variables and metabolic factors in indexes of high arterial stiffness. Thus, an inflammatory-metabolic background may influence the pathogenesis of increased arterial stiffness in seronegative inflammatory arthritis.

Expression, pharmacology and functional activity of adenosine A1 receptors in genetic models of Huntington's disease

Adenosine A1 receptor (A1R) stimulation exerts beneficial effects in response to various insults to the brain and, although it was found neuroprotective in a lesional model of Huntington's disease (HD), the features of this receptor in genetic models of HD have never been explored. In the present study we characterized the expression, affinity and functional effects of A1Rs in R6/2 mice (the most widely used transgenic model of HD) and in a cellular model of HD. Binding studies revealed that the density of A1Rs was significantly reduced in the cortex and the striatum of R6/2 mice compared to age-matched wild-type (WT), while receptor affinity was unchanged. The selective A1R agonist cyclopentyladenosine (CPA, 300nM) was significantly more effective in reducing synaptic transmission in corticostriatal slices from symptomatic R6/2 than in age-matched WT mice. Such an effect was due to a stronger inhibition of glutamate release from the pre-synaptic terminal. The different functional activities of A1Rs in HD mice were associated also to a different intracellular signaling pathway involved in the synaptic effect of CPA. In fact, while the PKA pathway was involved in both genotypes, p38 MAPK inhibitor SB203580 partially prevented synaptic effects of CPA in R6/2, but not in WT, mice; moreover, CPA differently modulated the phosphorylation status of p38 in the two genotypes. In vitro studies confirmed a different behavior of A1Rs in HD: CPA (100 nM for 5h) modulated cell viability in STHdh(Q111/Q111) (mhttHD cells), without affecting the viability of STHdh(Q7/Q7) (wthtt cells). This effect was prevented by the application of SB203580. Our results demonstrate that in the presence of the HD mutation A1Rs undergo profound changes in terms of expression, pharmacology and functional activity. These changes have to be taken in due account when considering A1Rs as a potential therapeutic target for this disease.

The in vitro addition of methotrexate and/or methylprednisolone determines peripheral reduction in Th17 and expansion of conventional Treg and of IL-10 producing Th17 lymphocytes in patients with early rheumatoid arthritis

The aim of our study was to evaluate methotrexate (MTX) and methylprednisolone (MP) effect on peripheral Th17 and Treg subsets in patients with rheumatoid arthritis (RA). We enrolled 15 patients (10 early RA and 5 long-standing disease) with active RA and 10 age-matched healthy donors as controls. Frequencies of Th17 and Treg were quantified using flow cytometry before and after in vitro addition of MTX, MP or both drugs. Our results showed a reduction in the overall Th17 population followed by an increase in Th17 IL-10(+) and Treg, after in vitro treatment of PBMCs with the drugs in patients with early RA. Long-standing disease patients showed a less evident increase in Treg cells and less enhancement of IL-10 Th17 cells. We suggest that the treatment with MTX and MP could ameliorate RA disease activity by normalizing the distribution/imbalance of Th17/Treg and indicate a new regulatory role of IL-17(+) cells in RA patients.

In vitro equine embryo production using air-dried spermatozoa, with different activation protocols and culture systems

The aim of this work was to evaluate the use of air-dried spermatozoa for in vitro production of equine embryos and verify if sperm extract activation and in vivo culture improve in vitro embryo production. Cooled spermatozoa (control) and air-dried spermatozoa stored for 2, 14 or 28 days were used for ICSI sperm extract, or ionomycin was used for oocyte activation, and embryos were in vitro or in vivo (in mare's oviduct) cultured for 7 days. With in vitro culture, cleavage rate was higher when activating with sperm extract (P < 0.05). No differences in embryo development were seen between the two activation treatments nor between storage periods (P > 0.05). Blastocysts were obtained with cooled spermatozoa, and morulae were achieved using in vivo culture with 28-day storage spermatozoa and ionomycin-activated oocytes. When in vivo culture was performed, sperm DNA fragmentation was assessed using the sperm chromatin dispersion test and did not show statistical correlation with cleavage nor embryo recovery rates. In conclusion, equine embryos can be produced using air-dried spermatozoa stored for several weeks. Sperm extract activation increased cleavage rates but did not improve embryo development. In vivo culture allowed intrauterine stage embryos to be achieved.

Cocaine-induced changes of synaptic transmission in the striatum are modulated by adenosine A2A receptors and involve the tyrosine phosphatase STEP

The striatum is a brain area implicated in the pharmacological action of drugs of abuse. Adenosine A2A receptors (A2ARs) are highly expressed in the striatum and mediate, at least in part, cocaine-induced psychomotor effects in vivo. Here we studied the synaptic mechanisms implicated in the pharmacological action of cocaine in the striatum and investigated the influence of A2ARs. We found that synaptic transmission was depressed in corticostriatal slices after perfusion with cocaine (10 μM). This effect was reduced by the A2AR antagonist ZM241385 and almost abolished in striatal A2AR-knockout mice (mice lacking A2ARs in striatal neurons, stA2ARKO). The effect of cocaine on synaptic transmission was also prevented by the protein tyrosine phosphatases (PTPs) inhibitor sodium orthovanadate (Na3VO4). In synaptosomes prepared from striatal slices, we found that the activity of striatal-enriched protein tyrosine phosphatase (STEP) was upregulated by cocaine, prevented by ZM241385, and absent in synaptosomes from stA2ARKO. The role played by STEP in cocaine modulation of synaptic transmission was investigated in whole-cell voltage clamp recordings from medium spiny neurons of the striatum. We found that TAT-STEP, a peptide that renders STEP enzymatically inactive, prevented cocaine-induced reduction in AMPA- and NMDA-mediated excitatory post-synaptic currents, whereas the control peptide, TAT-myc, had no effect. These results demonstrate that striatal A2ARs modulate cocaine-induced synaptic depression in the striatum and highlight the potential role of PTPs and specifically STEP in the effects of cocaine.

A whole-of-population study of the prevalence and patterns of criminal offending in people with schizophrenia and other mental illness

BACKGROUND

Large epidemiological studies are needed to better understand the prevalence and profile of offending by people with mental illness. This study used a whole-of-population design to examine the prevalence, type and pattern of offending across all psychiatric diagnoses, including schizophrenia, compared to the general population. Method We used whole-of-population longitudinal record-linked data for a cohort of all Western Australians born 1955-1969 to determine arrest history over the period 1985-1996 and to ascertain recorded history of psychiatric illness. Of the cohort, 116 656 had been arrested and 40 478 were on the psychiatric case register.

RESULTS

The period prevalence of arrest for people with any psychiatric illness was 32.1%. The highest arrest prevalence, by diagnostic category, was for substance use disorders (59.4%); the prevalence for schizophrenia was 38.7%. Co-morbid substance use disorders significantly increased risk of arrest in people with schizophrenia. The prevalence of mental illness among offenders was 11.1%: 6.5% of offenders had substance use disorders and 1.7% had schizophrenia. For the majority of offenders with a psychiatric illness, first arrest preceded first contact with mental health services; for schizophrenia only, this proportion was increasing over time. The mean percentage annual change in the number of arrests during 1985-1996 rose significantly for offenders with a psychiatric illness other than schizophrenia and dropped significantly for those with no mental illness. Compared to non-psychiatric offenders, offenders with schizophrenia were more likely to offend alone, to offend in open places and to target strangers.

CONCLUSIONS

Our findings open the way to an informed approach to the management of offenders with mental illness.

BDNF prevents NMDA-induced toxicity in models of Huntington's disease: the effects are genotype specific and adenosine A2A receptor is involved

NMDA receptor-mediated excitotoxicity is thought to play a pivotal role in the pathogenesis of Huntington's disease (HD). The neurotrophin brain-derived neurotrophic factor (BDNF), which is also highly involved in HD and whose effects are modulated by adenosine A2 ARs, influences the activity and expression of striatal NMDA receptors. In electrophysiology experiments, we investigated the role of BDNF toward NMDA-induced effects in HD models, and the possible involvement of A2ARs. In corticostriatal slices from wild-type mice and age-matched symptomatic R6/2 mice (a model of HD), NMDA application (75 μM) induced a transient or a permanent (i.e., toxic) reduction of field potential amplitude, respectively. BDNF (10 ng/mL) potentiated NMDA effects in wild-type, while it protected from NMDA toxicity in R6/2 mice. Both effects of BDNF were prevented by A2 AR blockade. The protective effect of BDNF against NMDA-induced toxicity was reproduced in a cellular model of HD. These findings may have very important implications for the neuroprotective potential of BDNF and A2 AR ligands in HD.

Effects of chronic caffeine intake in a mouse model of amyotrophic lateral sclerosis

Caffeine is a nonselective adenosine receptor antagonist; chronic consumption has proved protective toward neurodegenerative diseases such as Parkinson's and Alzheimer's diseases. The present study was designed to determine whether caffeine intake affected survival and/or motor performance in a transgenic model of amyotrophic lateral sclerosis (ALS). SOD1(G93A) mice received caffeine through drinking water from 70 days of age until death. Body weight, motor performance and survival were evaluated. Furthermore, the expression of adenosine A(2A) receptors (A(2A) Rs), glial glutamate transporter (GLT1), and glial fibrillar acidic protein (GFAP) were evaluated by Western blotting. The results showed that caffeine intake significantly shortened the survival of SOD1(G93A) mice (log rank test, P = 0.01) and induced a nonsignificant advancing of disease onset. The expression of A(2A) R, GLT1, and GFAP was altered in the spinal cords of ALS mice, but caffeine did not influence their expression in either wild-type or SOD1(G93) mice. These data indicate that adenosine receptors may play an important role in ALS.

Reduced social interaction, behavioural flexibility and BDNF signalling in the BTBR T+ tf/J strain, a mouse model of autism

Autism is a neurodevelopmental disorder characterized by social and communication impairments and repetitive behaviours. The inbred BTBR T+ tf/J (BTBR) strain, a putative mouse model of autism, exhibits lower social interactions, higher repetitive self-grooming levels and unusual pattern of vocalizations as compared to C57BL/6J strain. First aim of the present study was to evaluate at adolescence (postnatal days 30-35) male BTBR and C57BL/6J performances in two different tasks involving either investigation of social cues (same strain partners) or non social ones (inanimate objects). In the social interaction test, BTBR mice showed a reduction of investigation of the social partner, due to a selective reduction of head sniffing, associated with a decrease in ultrasonic vocalizations. By contrast, no strain differences were detected in object investigations. Second aim of the study was to evaluate adult male BTBR and C57BL/6J performances in a fear conditioning task. Strain differences were evident during contextual retest: these strain differences primarily suggested a lack of behavioural flexibility in BTBR mice (i.e., realizing the occurrence of changes in the experimental paradigm). Subsequent electrophysiological analysis in hippocampal slices from adult BTBR and C57BL/6J mice revealed a significant reduction of Brain Derived Neurotrophic Factor (BDNF)-induced potentiation of synaptic transmission in BTBR mice. BDNF and tyrosine kinase B (TrkB) protein levels measured in the hippocampal region were also lower in BTBR as compared to C57BL/6J mice. These data confirm the presence of low levels of direct interaction with social stimuli in BTBR mice at adolescence, in the absence of any strain difference as for investigation of physical objects. At adulthood in BTBR mice clear signs of behavioural inflexibility were evident whereas both biochemical and electrophysiological data point to decreased BDNF signalling (likely due to a reduction in TrkB levels) in the hippocampus of this mouse strain.

Neonatal protein kinase C zeta expression determines the neonatal T-Cell cytokine phenotype and predicts the development and severity of infant allergic disease

BACKGROUND

Previous studies have demonstrated that reduced T-cell protein kinase C zeta (PKCζ) expression is associated with allergy development in infants born to atopic mothers. This study examined whether this relationship extends to a general population and addressed the basis for the association.

METHODS

A flow cytometry assay was developed for the measurement of T-cell PKCζ levels in PBMC, cord blood mononuclear cell and whole blood. Cord blood T-cell PKCζ levels were measured in 135 neonates, and allergic disease was evaluated by skin prick test and clinical examination at 12 months of age.

RESULTS

Allergic children (particularly those with eczema) had significantly lower neonatal T-cell PKCζ expression than nonallergic children (P < 0.001). PKCζ levels predicted allergic disease with optimal specificity of 86% and sensitivity of 54%. The sensitivity was increased in the children of allergic mothers, who had significantly lower PKC levels than the children of nonallergic mothers. Cord blood PKCζ levels did not affect T-cell maturation in culture as assessed by CD45RA/RO expression, but low PKCζ expression was associated with reduced capacity for IFNγ production by matured T cells. Low cord blood PKC expression was further associated with increased IL-13 responses at 6 months.

CONCLUSIONS

The findings suggest a potential role for the use of PKCζ levels in cord blood T cells as a presymptomatic test to predict allergy risk in children, particularly offspring of allergic mothers, and that the basis of this relationship is related to cytokine patterns in mature T cells.