Regulatory T Cell Migration Is Dependent on Glucokinase-Mediated Glycolysis.

Migration of activated regulatory T (Treg) cells to inflamed tissue is crucial for their immune-modulatory function. While metabolic reprogramming during Treg cell differentiation has been extensively studied, the bioenergetics of Treg cell trafficking remains undefined. We have investigated the metabolic demands of migrating Treg cells in vitro and in vivo. We show that glycolysis was instrumental for their migration and was initiated by pro-migratory stimuli via a PI3K-mTORC2-mediated pathway culminating in induction of the enzyme glucokinase (GCK). Subsequently, GCK promoted cytoskeletal rearrangements by associating with actin. Treg cells lacking this pathway were functionally suppressive but failed to migrate to skin allografts and inhibit rejection. Similarly, human carriers of a loss-of-function GCK regulatory protein gene-leading to increased GCK activity-had reduced numbers of circulating Treg cells. These cells displayed enhanced migratory activity but similar suppressive function, while conventional T cells were unaffected. Thus, GCK-dependent glycolysis regulates Treg cell migration.

Placental Inflammation Leads to Abnormal Embryonic Heart Development.

BACKGROUND: Placental heart development and embryonic heart development occur in parallel, and these organs have been proposed to exert reciprocal regulation during gestation. Poor placentation has been associated with congenital heart disease, an important cause of infant mortality. However, the mechanisms by which altered placental development can lead to congenital heart disease remain unresolved. METHODS: In this study, we use an in vivo neutrophil-driven placental inflammation model through antibody depletion of maternal circulating neutrophils at key stages during time-mated murine pregnancy: embryonic days 4.5 and 7.5. Pregnant mice were culled at embryonic day 14.5 to assess placental and embryonic heart development. A combination of flow cytometry, histology, and bulk RNA sequencing was used to assess placental immune cell composition and tissue architecture. We also used flow cytometry and single-cell sequencing to assess embryonic cardiac immune cells at embryonic day 14.5 and histology and gene analyses to investigate embryonic heart structure and development. In some cases, offspring were culled at postnatal days 5 and 28 to assess any postnatal cardiac changes in immune cells, structure, and cardiac function, as measured by echocardiography. RESULTS: In the present study, we show that neutrophil-driven placental inflammation leads to inadequate placental development and loss of barrier function. Consequently, placental inflammatory monocytes of maternal origin become capable of migration to the embryonic heart and alter the normal composition of resident cardiac macrophages and cardiac tissue structure. This cardiac impairment continues into postnatal life, hindering normal tissue architecture and function. Last, we show that tempering placental inflammation can prevent this fetal cardiac defect and is sufficient to promote normal cardiac function in postnatal life. CONCLUSIONS: Taken together, these observations provide a mechanistic paradigm whereby neutrophil-driven inflammation in pregnancy can preclude normal embryonic heart development as a direct consequence of poor placental development, which has major implications on cardiac function into adult life.

Neutrophils in pregnancy: New insights into innate and adaptive immune regulation.

The immunology of pregnancy has been the focus of many studies to better understand how the mother is able to tolerate the presence of a semi-allogeneic fetus. Far from the initial view of pregnancy as a state of immunosuppression, successful fetal development from implantation to birth is now known to be under the control of an intricate balance of immune cells. The balance between pro-inflammatory functions used to promote embryo implantation and placental development and immunosuppressive activity to maintain maternal tolerance of the fetus is an immunological phenotype unique to pregnancy, which is dependent on the time of gestation. Neutrophils are one of a host of innate immune cells detected at the maternal-fetal interface, but very little is known of their function. In this review, we explore the emerging functions of neutrophils during pregnancy and their interactions with and regulation of T cells, a key adaptive immune cell population essential for the establishment of fetal-maternal tolerance.

Mechanisms of T cell organotropism.

Protective immunity relies upon T cell differentiation and subsequent migration to target tissues. Similarly, immune homeostasis requires the localization of regulatory T cells (Tregs) to the sites where immunity takes place. While naïve T lymphocytes recirculate predominantly in secondary lymphoid tissue, primed T cells and activated Tregs must traffic to the antigen rich non-lymphoid tissue to exert effector and regulatory responses, respectively. Following priming in draining lymph nodes, T cells acquire the 'homing receptors' to facilitate their access to specific tissues and organs. An additional level of topographic specificity is provided by T cells receptor recognition of antigen displayed by the endothelium. Furthermore, co-stimulatory signals (such as those induced by CD28) have been shown not only to regulate T cell activation and differentiation, but also to orchestrate the anatomy of the ensuing T cell response. We here review the molecular mechanisms supporting trafficking of both effector and regulatory T cells to specific antigen-rich tissues.

Is implicit Level-2 visual perspective-taking embodied? Spontaneous perceptual simulation of others' perspectives is not impaired by motor restriction.

Visual perspective taking may rely on the ability to mentally rotate one's own body into that of another. Here, we test whether participants' ability to make active body movements plays a causal role in visual perspective taking. We utilised our recent task that measures whether participants spontaneously represent another's visual perspective in a (quasi-)perceptual format that can drive own perceptual decision making. Participants reported whether alphanumeric characters, presented in different orientations, are shown in their normal or mirror-inverted form (e.g., "R" vs. "Я"). Between trials, we manipulated whether another person was sitting either left or right of the character and whether participants' movement was restricted with a chinrest or whether they could move freely. As in our previous research, participants spontaneously took the visual perspective of the other person, recognising rotated letters more rapidly when they appeared upright to the other person in the scene, compared with when they faced away from that person, and these effects increased with age but were (weakly) negatively related to schizotypy and not to autistic traits or social skills. Restricting participants' ability to make active body movements did not influence these effects. The results, therefore, rule out that active physical movement plays a causal role in computing another's visual perspective, either to create alignment between own and other's perspective or to trigger perspective taking processes. The postural adjustments people sometimes make when making judgements from another's perspective may instead be a bodily consequence of mentally transforming one's actual to an imagined position in space.

Loss of mTORC2-induced metabolic reprogramming in monocytes uncouples migration and maturation from production of proinflammatory mediators.

Monocyte migration to the sites of inflammation and maturation into macrophages are key steps for their immune effector function. Here, we show that mechanistic target of rapamycin complex 2 (mTORC2)-dependent Akt activation is instrumental for metabolic reprogramming at the early stages of macrophage-mediated immunity. Despite an increased production of proinflammatory mediators, monocytes lacking expression of the mTORC2 component Rictor fail to efficiently migrate to inflammatory sites and fully mature into macrophages, resulting in reduced inflammatory responses in vivo. The mTORC2-dependent phosphorylation of Akt is instrumental for the enhancement of glycolysis and mitochondrial respiration, required to sustain monocyte maturation and motility. These observations are discussed in the context of therapeutic strategies aimed at selective inhibition of mTORC2 activity.

Loss of voltage-gated hydrogen channel 1 expression reveals heterogeneous metabolic adaptation to intracellular acidification by T cells.

Voltage-gated hydrogen channel 1 (Hvcn1) is a voltage-gated proton channel, which reduces cytosol acidification and facilitates the production of ROS. The increased expression of this channel in some cancers has led to proposing Hvcn1 antagonists as potential therapeutics. While its role in most leukocytes has been studied in depth, the function of Hvcn1 in T cells remains poorly defined. We show that Hvcn1 plays a nonredundant role in protecting naive T cells from intracellular acidification during priming. Despite sharing overall functional impairment in vivo and in vitro, Hvcn1-deficient CD4+ and CD8+ T cells display profound differences during the transition from naive to primed T cells, including in the preservation of T cell receptor (TCR) signaling, cellular division, and death. These selective features result, at least in part, from a substantially different metabolic response to intracellular acidification associated with priming. While Hvcn1-deficient naive CD4+ T cells reprogram to rescue the glycolytic pathway, naive CD8+ T cells, which express high levels of this channel in the mitochondria, respond by metabolically compensating mitochondrial dysfunction, at least in part via AMPK activation. These observations imply heterogeneity between adaptation of naive CD4+ and CD8+ T cells to intracellular acidification during activation.

Prognostic impact of chromosomal abnormalities and copy number alterations in adult B-cell precursor acute lymphoblastic leukaemia: a UKALL14 study.

Chromosomal abnormalities are established prognostic markers in adult ALL. We assessed the prognostic impact of established chromosomal abnormalities and key copy number alterations (CNA) among 652 patients with B-cell precursor ALL treated on a modern MRD driven protocol. Patients with KMT2A-AFF1, complex karyotype (CK) and low hypodiploidy/near-triploidy (HoTr) had high relapse rates 50%, 60% & 53% and correspondingly poor survival. Patients with BCR-ABL1 had an outcome similar to other patients. JAK-STAT abnormalities (CRLF2, JAK2) occurred in 6% patients and were associated with a high relapse rate (56%). Patients with ABL-class fusions were rare (1%). A small group of patients with ZNF384 fusions (n = 12) had very good survival. CNA affecting IKZF1, CDKN2A/B, PAX5, BTG1, ETV6, EBF1, RB1 and PAR1 were assessed in 436 patients. None of the individual deletions or profiles were associated with survival, either in the cohort overall or within key subgroups. Collectively these data indicate that primary genetic abnormalities are stronger prognostic markers than secondary deletions. We propose a revised UKALL genetic risk classification based on key established chromosomal abnormalities: (1) very high risk: CK, HoTr or JAK-STAT abnormalities; (2) high risk: KMT2A fusions; (3) Tyrosine kinase activating: BCR-ABL1 and ABL-class fusions; (4) standard risk: all other patients.

Perspective taking as virtual navigation? Perceptual simulation of what others see reflects their location in space but not their gaze.

Other peoples' (imagined) visual perspectives are represented perceptually in a similar way to our own, and can drive bottom-up processes in the same way as own perceptual input (Ward, Ganis, & Bach, 2019). Here we test directly whether visual perspective taking is driven by where another person is looking, or whether these perceptual simulations represent their position in space more generally. Across two experiments, we asked participants to identify whether alphanumeric characters, presented at one of eight possible orientations away from upright, were presented normally, or in their mirror-inverted form (e.g. "R" vs. "Я"). In some scenes, a person would appear sitting to the left or the right of the participant. We manipulated either between-trials (Experiment 1) or between-subjects (Experiment 2), the gaze-direction of the inserted person, such that they either (1) looked towards the to-be-judged item, (2) averted their gaze away from the participant, or (3) gazed out towards the participant (Exp. 2 only). In the absence of another person, we replicated the well-established mental rotation effect, where recognition of items becomes slower the more items are oriented away from upright (e.g. Shepard and Meltzer, 1971). Crucially, in both experiments and in all conditions, this response pattern changed when another person was inserted into the scene. People spontaneously took the perspective of the other person and made faster judgements about the presented items in their presence if the characters were oriented towards upright to them. The gaze direction of this other person did not influence these effects. We propose that visual perspective taking is therefore a general spatial-navigational ability, allowing us to calculate more easily how a scene would (in principle) look from another position in space, and that such calculations reflect the spatial location of another person, but not their gaze.

Affordance matching predictively shapes the perceptual representation of others' ongoing actions.

Predictive processing accounts of social perception argue that action observation is a predictive process, in which inferences about others' goals are tested against the perceptual input, inducing a subtle perceptual confirmation bias that distorts observed action kinematics toward the inferred goals. Here we test whether such biases are induced even when goals are not explicitly given but have to be derived from the unfolding action kinematics. In 2 experiments, participants briefly saw an actor reach ambiguously toward a large object and a small object, with either a whole-hand power grip or an index-finger and thumb precision grip. During its course, the hand suddenly disappeared, and participants reported its last seen position on a touch-screen. As predicted, judgments were consistently biased toward apparent action targets, such that power grips were perceived closer to large objects and precision grips closer to small objects, even if the reach kinematics were identical. Strikingly, these biases were independent of participants' explicit goal judgments. They were of equal size when action goals had to be explicitly derived in each trial (Experiment 1) or not (Experiment 2) and, across trials and across participants, explicit judgments and perceptual biases were uncorrelated. This provides evidence, for the first time, that people make online adjustments of observed actions based on the match between hand grip and object goals, distorting their perceptual representation toward implied goals. These distortions may not reflect high-level goal assumptions, but emerge from relatively low-level processing of kinematic features within the perceptual system. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Spontaneous Vicarious Perception of the Content of Another's Visual Perspective.

Visual perspective taking (VPT) is a core process of social cognition, providing humans with insights into what the environment looks like from another's point of view [1-4]. While VPT is often described as a quasi-perceptual phenomenon [5, 6], evidence for this proposal has been lacking. Here, we provide direct evidence that another's perspective can "stand in" for one's own sensory input during perceptual decision making. In a variant of the classic mental rotation task, participants judged whether characters presented in different orientations were canonical or mirror inverted. In the absence of another person, we replicate the well-established positive linear relationship between recognition times and angle of orientation such that recognition becomes slower the more an item has to be mentally rotated into its canonical orientation [7]. Importantly, this relationship was disrupted simply by placing another individual in the scene. Items rotated away from the participant were recognized more rapidly the closer they appeared in their canonical orientation, not only to the participant, but also to this other individual, showing that another's visual perspective drives mental rotation and item recognition in a similar way as one's own visual perspective. The effects were large and replicated in the three independent studies. They were observed even when the other person was completely passive, enhanced when the participant was explicitly instructed to take the other person's perspective, but reduced when the persons in the scenes were replaced with objects. The content of another's perspective is therefore spontaneously derived, takes a quasi-perceptual form, and can stand in for one's own sensory input during perceptual decision making.

Engineered hexavalent Fc proteins with enhanced Fc-gamma receptor avidity provide insights into immune-complex interactions.

Autoantibody-mediated diseases are currently treated with intravenous immunoglobulin, which is thought to act in part via blockade of Fc gamma receptors, thereby inhibiting autoantibody effector functions and subsequent pathology. We aimed to develop recombinant molecules with enhanced Fc receptor avidity and thus increased potency over intravenous immunoglobulin. Here we describe the molecular engineering of human Fc hexamers and explore their therapeutic and safety profiles. We show Fc hexamers were more potent than IVIG in phagocytosis blockade and disease models. However, in human whole-blood safety assays incubation with IgG1 isotype Fc hexamers resulted in cytokine release, platelet and complement activation, whereas the IgG4 version did not. We used a statistically designed mutagenesis approach to identify the key Fc residues involved in these processes. Cytokine release was found to be dependent on neutrophil FcγRIIIb interactions with L234 and A327 in the Fc. Therefore, Fc hexamers provide unique insights into Fc receptor biology.

Discovery of a Potent, Orally Bioavailable PI4KIIIß Inhibitor (UCB9608) Able To Significantly Prolong Allogeneic Organ Engraftment in Vivo.

The primary target of a novel series of immunosuppressive 7-piperazin-1-ylthiazolo[5,4- d]pyrimidin-5-amines was identified as the lipid kinase, PI4KIIIß. Evaluation of the series highlighted their poor solubility and unwanted off-target activities. A medicinal chemistry strategy was put in place to optimize physicochemical properties within the series, while maintaining potency and improving selectivity over other lipid kinases. Compound 22 was initially identified and profiled in vivo, before further modifications led to the discovery of 44 (UCB9608), a vastly more soluble, selective compound with improved metabolic stability and excellent pharmacokinetic profile. A co-crystal structure of 44 with PI4KIIIß was solved, confirming the binding mode of this class of inhibitor. The much-improved in vivo profile of 44 positions it as an ideal tool compound to further establish the link between PI4KIIIß inhibition and prolonged allogeneic organ engraftment, and suppression of immune responses in vivo.

Monitoring Migration of Activated T Cells to Antigen-Rich Non-lymphoid Tissue.

Effective immunity requires appropriate recirculation of naïve T cells through secondary lymphoid organs and migration of antigen-specific T cells to sites of inflammation. Leukocyte migration is a highly regulated process requiring specific interactions between leukocytes and endothelial cells (EC) termed collectively as the leukocyte adhesion cascade. Recruitment and retention of activated T cells to antigen-rich sites of inflammation is a key event in the immune response, which relies in part on local antigen presentation particularly by EC of inflamed vessels. Here we describe methods to assess the contributions of different molecules on antigen-dependent T cell migration, by utilizing IFN-γ to upregulate MHC molecules on EC and local antigen presentation, both in vitro and in vivo.