Pericytes and the Control of Blood Flow in Brain and Heart.

Pericytes, attached to the surface of capillaries, play an important role in regulating local blood flow. Using optogenetic tools and genetically encoded reporters in conjunction with confocal and multiphoton imaging techniques, the 3D structure, anatomical organization, and physiology of pericytes have recently been the subject of detailed examination. This work has revealed novel functions of pericytes and morphological features such as tunneling nanotubes in brain and tunneling microtubes in heart. Here, we discuss the state of our current understanding of the roles of pericytes in blood flow control in brain and heart, where functions may differ due to the distinct spatiotemporal metabolic requirements of these tissues. We also outline the novel concept of electro-metabolic signaling, a universal mechanistic framework that links tissue metabolic state with blood flow regulation by pericytes and vascular smooth muscle cells, with capillary KATP and Kir2.1 channels as primary sensors. Finally, we present major unresolved questions and outline how they can be addressed.

Effects of three different plant-derived polysaccharides on growth performance, immunity, antioxidant function, and cecal microbiota of broilers.

BACKGROUND: This study investigated the effects of dietary plant polysaccharides on growth performance, immune status and intestinal health in broilers. We randomly divided 960 one-day-old Arbor Acres broiler chicks into four groups. The control (CON) group was fed a basal diet, and the remaining groups were fed a basal diet supplemented with 1000 mg kg-1 Ginseng polysaccharide (GPS), Astragalus polysaccharide (APS), or Salvia miltiorrhiza polysaccharide (SMP) for 42 days. RESULTS: Dietary supplementation with SMP significantly increased body weight (BW) at 21 and 42 days of age, average daily gain (ADG) and average daily feed intake (ADFI) during the starter and whole experimental period, decreased the concentrations of interleukin-1 beta (IL-1ß), tumor necrosis factor α (TNF-α) and malondialdehyde (MDA), increased the levels of interleukin-4 (IL-4) and interleukin-10 (IL-10) and catalase (CAT) activity in the serum (P < 0.05). GPS, APS, and SMP supplementation increased serum levels of immunoglobulins, activities of glutathione peroxidase (GSH-Px), total superoxide dismutase (T-SOD) and total antioxidant capacity (T-AOC), and cecal concentrations of acetic acid and propionic acid of broilers (P < 0.05). Furthermore, high-throughput sequencing results showed that the relative abundance of Firmicutes was decreased while the relative abundance of Bacteroidota, Alistipes, and Prevotellaceae_NK3B31_group were increased (P < 0.05) in the GPS, APS, and SMP groups compared with the CON group. CONCLUSION: Dietary GPS, APS, and SMP supplementation could improve growth performance, enhance immune function by increasing serum immunoglobulin and regulating cytokines, improve antioxidant function by increasing serum antioxidant enzyme activity, increase volatile fatty acid levels and improve the microbial composition in the cecum of broilers. Dietary SMP supplementation had the optimal effect in this study. © 2023 Society of Chemical Industry.

ATP- and voltage-dependent electro-metabolic signaling regulates blood flow in heart.

Local control of blood flow in the heart is important yet poorly understood. Here we show that ATP-sensitive K+ channels (KATP), hugely abundant in cardiac ventricular myocytes, sense the local myocyte metabolic state and communicate a negative feedback signal-correction upstream electrically. This electro-metabolic voltage signal is transmitted instantaneously to cellular elements in the neighboring microvascular network through gap junctions, where it regulates contractile pericytes and smooth muscle cells and thus blood flow. As myocyte ATP is consumed in excess of production, [ATP]i decreases to increase the openings of KATP channels, which biases the electrically active myocytes in the hyperpolarization (negative) direction. This change leads to relative hyperpolarization of the electrically connected cells that include capillary endothelial cells, pericytes, and vascular smooth muscle cells. Such hyperpolarization decreases pericyte and vascular smooth muscle [Ca2+]i levels, thereby relaxing the contractile cells to increase local blood flow and delivery of nutrients to the local cardiac myocytes and to augment ATP production by their mitochondria. Our findings demonstrate the pivotal roles of local cardiac myocyte metabolism and KATP channels and the minor role of inward rectifier K+ (Kir2.1) channels in regulating blood flow in the heart. These findings establish a conceptually new framework for understanding the hugely reliable and incredibly robust local electro-metabolic microvascular regulation of blood flow in heart.

Role of the thymus in spontaneous development of a multi-organ autoimmune disease in human immune system mice.

We evaluated the role of the thymus in development of multi-organ autoimmunity in human immune system (HIS) mice. T cells were essential for disease development and the same T cell clones with varying phenotypes infiltrated multiple tissues. De novo-generated hematopoietic stem cell (HSC)-derived T cells were the major disease drivers, though thymocytes pre-existing in grafted human thymi contributed if not first depleted. HIS mice with a native mouse thymus developed disease earlier than thymectomized mice with a thymocyte-depleted human thymus graft. Defective structure in the native mouse thymus was associated with impaired negative selection of thymocytes expressing a transgenic TCR recognizing a self-antigen. Disease developed without direct recognition of antigens on recipient mouse MHC. While human thymus grafts had normal structure and negative selection, failure to tolerize human T cells recognizing mouse antigens presented on HLA molecules may explain eventual disease development. These new insights have implications for human autoimmunity and suggest methods of avoiding autoimmunity in next-generation HIS mice.

Dynamics of the mitochondrial permeability transition pore: Transient and permanent opening events.

A gentle optical examination of the mitochondrial permeability transition pore (mPTP) opening events was carried out in isolated quiescent ventricular myocytes by tracking the inner membrane potential (ΔΨM) using TMRM (tetramethylrhodamine methyl ester). Zeiss Airyscan 880 ″super-resolution" or "high-resolution" imaging was done with very low levels of illumination (0.009% laser power). In cellular areas imaged every 9 s (ROI or regions of interest), transient depolarizations of variable amplitudes occurred at increasing rates for the first 30 min. The time to first depolarization events was 8.4 min (±1.1 SEM n = 21 cells). At longer times, essentially permanent and irreversible depolarizations occurred at an increasing fraction of all events. In other cellular areas surrounding the ROI, mitochondria were rarely illuminated (once per 5 min) and virtually no permanent depolarization events occurred for over 1 h of imaging. These findings suggest that photon stress due to the imaging itself plays an important role in the generation of both the transient mPTP opening events as well as the permanent mPTP opening events. Consistent with the evidence that photon "stress" in mitochondria loaded with virtually any photon absorbing substance, generates reactive oxygen species (ROS) [1-5], we show that cyclosporine-A (CsA, 10 µM) and the antioxidant n-acetyl cysteine (NAC, 10 mM), reduced the number of events by 80% and 93% respectively. Furthermore, CsA and NAC treatment led to the virtual disappearance of permanent depolarization events. Nevertheless, all transient depolarization events in any condition (control, CsA and NAC) appeared to repolarize with a similar half-time of 30 ±â€¯6 s (n = 478) at 37 °C. Further experiments showed quantitatively similar results in cerebral vascular smooth muscle cells, using a different confocal system, and different photon absorbing reagent (TMRE; tetramethylrhodamine ethyl ester). In these experiments, using modest power (1% laser power) transient depolarization events were seen in only 8 out of 23 cells while with higher power (8%), all cells showed transient events, which align with the level of photon stress being the driver of the effect. Together, our findings suggest that photon-induced ROS is sufficient to cause depolarization events of individual mitochondria in quiescent cells; without electrical or mechanical activity to stimulates mitochondrial metabolism, and without raising the mitochondrial matrix Ca2+. In a broad context, these findings neither support nor deny the relevance or occurrence of ΔΨM depolarization events in specific putatively physiologic mitochondrial behaviors such as MitoFlashes [6,7] or MitoWinks [8]. Instead, our findings raise a caution with regards to the physiological and pathophysiological functions attributed to singular ΔΨM depolarization events when those functions are investigated using photon absorbing substances. Nevertheless, using photon stress as a tool ("Optical Stress-Probe"), we can extract information on the activation, reversibility, permanency and kinetics of mitochondrial depolarization. These data may provide new information on mPTP, help identify the mPTP protein complex, and establish the physiological function of the mPTP protein complex and their links to MitoFlashes and MitoWinks.

Discovery of a class of highly potent Janus Kinase 1/2 (JAK1/2) inhibitors demonstrating effective cell-based blockade of IL-13 signaling.

Disruption of interleukin-13 (IL-13) signaling with large molecule antibody therapies has shown promise in diseases of allergic inflammation. Given that IL-13 recruits several members of the Janus Kinase family (JAK1, JAK2, and TYK2) to its receptor complex, JAK inhibition may offer an alternate small molecule approach to disrupting IL-13 signaling. Herein we demonstrate that JAK1 is likely the isoform most important to IL-13 signaling. Structure-based design was then used to improve the JAK1 potency of a series of previously reported JAK2 inhibitors. The ability to impede IL-13 signaling was thereby significantly improved, with the best compounds exhibiting single digit nM IC50's in cell-based assays dependent upon IL-13 signaling. Appropriate substitution was further found to influence inhibition of a key off-target, LRRK2. Finally, the most potent compounds were found to be metabolically labile, which makes them ideal scaffolds for further development as topical agents for IL-13 mediated diseases of the lungs and skin (for example asthma and atopic dermatitis, respectively).

Diagnostic Function of 3D Optical Coherence Tomography Images in Diagnosis of Vogt-Koyanagi-Harada Disease at Acute Uveitis Stage.

BACKGROUND This study analyzed the macular 3D-OCT images of Vogt-Koyanagi-Harada disease (VKH) in uveitis, explored the characteristics of 3D-OCT images of the macular region of VKH, and assessed which characteristics contribute most to VKH diagnosis. MATERIAL AND METHODS The 3D-OCT examination of 25 cases of VKH was performed on the macular area, and the image characteristics were analyzed. RESULTS Our study included a total of 50 eyes from 25 cases of VKH patients, 10 males and 15 females, aged 17 to 64 years, mean (39.44±11.60) years old. According to OCT B-scan images, 49 (98%) eyes had ERD, 49 (98%) eyes had nerve retinal edema, 36 (72%) eyes had endometrium-like structure (including cysts), 5 (10%) eyes had RPE folds, 35 (70%) eyes had changes in the internal septum, 49 (98%) eyes had RPE monolayer structure outside the ERD region. In ILM-RPE thickness, 49 (98%) eyes had retinal irregular thickening and 31 (62%) eyes had radial stripe changes. In ILM contour figure, 50 eyes (100%) showed exceptional uplift, 5 (10%) eyes had small focal uplift for PED on the RPE surface, and 48 (96%) eyes had wavy ups and downs. CONCLUSIONS In OCT B-scan imaging, the ERT, retinal edema of the retina, and the RPE monolayer structure outside the range are most likely to occur in VKH. The ILM-RPE thickness chart in 3D reconstruction showed irregular thickening of the retina. The ILM contour graph showed abnormal uplift, and RPE surface wavy ups and downs in VKH most likely to occur.

STIM1 enhances SR Ca2+ content through binding phospholamban in rat ventricular myocytes.

In ventricular myocytes, the physiological function of stromal interaction molecule 1 (STIM1), an endo/sarcoplasmic reticulum (ER/SR) Ca(2+) sensor, is unclear with respect to its cellular localization, its Ca(2+)-dependent mobilization, and its action on Ca(2+) signaling. Confocal microscopy was used to measure Ca(2+) signaling and to track the cellular movement of STIM1 with mCherry and immunofluorescence in freshly isolated adult rat ventricular myocytes and those in short-term primary culture. We found that endogenous STIM1 was expressed at low but measureable levels along the Z-disk, in a pattern of puncta and linear segments consistent with the STIM1 localizing to the junctional SR (jSR). Depleting SR Ca(2+) using thapsigargin (2-10 µM) changed neither the STIM1 distribution pattern nor its mobilization rate, evaluated by diffusion coefficient measurements using fluorescence recovery after photobleaching. Two-dimensional blue native polyacrylamide gel electrophoresis and coimmunoprecipitation showed that STIM1 in the heart exists mainly as a large protein complex, possibly a multimer, which is not altered by SR Ca(2+) depletion. Additionally, we found no store-operated Ca(2+) entry in control or STIM1 overexpressing ventricular myocytes. Nevertheless, STIM1 overexpressing cells show increased SR Ca(2+) content and increased SR Ca(2+) leak. These changes in Ca(2+) signaling in the SR appear to be due to STIM1 binding to phospholamban and thereby indirectly activating SERCA2a (Sarco/endoplasmic reticulum Ca(2+) ATPase). We conclude that STIM1 binding to phospholamban contributes to the regulation of SERCA2a activity in the steady state and rate of SR Ca(2+) leak and that these actions are independent of store-operated Ca(2+) entry, a process that is absent in normal heart cells.

STIM1-Ca2+ signaling modulates automaticity of the mouse sinoatrial node.

Cardiac pacemaking is governed by specialized cardiomyocytes located in the sinoatrial node (SAN). SAN cells (SANCs) integrate voltage-gated currents from channels on the membrane surface (membrane clock) with rhythmic Ca(2+) release from internal Ca(2+) stores (Ca(2+) clock) to adjust heart rate to meet hemodynamic demand. Here, we report that stromal interaction molecule 1 (STIM1) and Orai1 channels, key components of store-operated Ca(2+) entry, are selectively expressed in SANCs. Cardiac-specific deletion of STIM1 in mice resulted in depletion of sarcoplasmic reticulum (SR) Ca(2+) stores of SANCs and led to SAN dysfunction, as was evident by a reduction in heart rate, sinus arrest, and an exaggerated autonomic response to cholinergic signaling. Moreover, STIM1 influenced SAN function by regulating ionic fluxes in SANCs, including activation of a store-operated Ca(2+) current, a reduction in L-type Ca(2+) current, and enhancing the activities of Na(+)/Ca(2+) exchanger. In conclusion, these studies reveal that STIM1 is a multifunctional regulator of Ca(2+) dynamics in SANCs that links SR Ca(2+) store content with electrical events occurring in the plasma membrane, thereby contributing to automaticity of the SAN.

Rapid Functional Decline of Activated and Memory Graft-versus-Host-Reactive T Cells Encountering Host Antigens in the Absence of Inflammation.

Inflammation in the priming host environment has critical effects on the graft-versus-host (GVH) responses mediated by naive donor T cells. However, it is unclear how a quiescent or inflammatory environment impacts the activity of GVH-reactive primed T and memory cells. We show in this article that GVH-reactive primed donor T cells generated in irradiated recipients had diminished ability compared with naive T cells to increase donor chimerism when transferred to quiescent mixed allogeneic chimeras. GVH-reactive primed T cells showed marked loss of cytotoxic function and activation, and delayed but not decreased proliferation or accumulation in lymphoid tissues when transferred to quiescent mixed chimeras compared with freshly irradiated secondary recipients. Primed CD4 and CD8 T cells provided mutual help to sustain these functions in both subsets. CD8 help for CD4 cells was largely IFN-γ dependent. TLR stimulation after transfer of GVH-reactive primed T cells to mixed chimeras restored their cytotoxic effector function and permitted the generation of more effective T cell memory in association with reduced PD-1 expression on CD4 memory cells. Our data indicate that an inflammatory host environment is required for the maintenance of GVH-reactive primed T cell functions and the generation of memory T cells that can rapidly acquire effector functions. These findings have important implications for graft-versus-host disease and T cell-mediated immunotherapies.

Mechanical activation of angiotensin II type 1 receptors causes actin remodelling and myogenic responsiveness in skeletal muscle arterioles.

KEY POINTS: Candesartan, an inverse agonist of the type 1 angiotensin II receptor (AT1 R), causes a concentration-dependent inhibition of pressure-dependent myogenic tone consistent with previous reports of mechanosensitivity of this G protein-coupled receptor. Mechanoactivation of the AT1 R occurs independently of local angiotensin II production and the type 2 angiotensin receptor. Mechanoactivation of the AT1 R stimulates actin polymerization by a protein kinase C-dependent mechanism, but independently of a change in intracellular Ca2+ . Using atomic force microscopy, changes in single vascular smooth muscle cell cortical actin are observed to remodel following mechanoactivation of the AT1 R. ABSTRACT: The Gq/11 protein-coupled angiotensin II type 1 receptor (AT1 R) has been shown to be activated by mechanical stimuli. In the vascular system, evidence supports the AT1 R being a mechanosensor that contributes to arteriolar myogenic constriction. The aim of this study was to determine if AT1 R mechanoactivation affects myogenic constriction in skeletal muscle arterioles and to determine underlying cellular mechanisms. Using pressure myography to study rat isolated first-order cremaster muscle arterioles the AT1 R inhibitor candesartan (10-7 -10-5  m) showed partial but concentration-dependent inhibition of myogenic reactivity. Inhibition was demonstrated by a rightward shift in the pressure-diameter relationship over the intraluminal pressure range, 30-110 mmHg. Pressure-induced changes in global vascular smooth muscle intracellular Ca2+ (using Fura-2) were similar in the absence or presence of candesartan, indicating that AT1 R-mediated myogenic constriction relies on Ca2+ -independent downstream signalling. The diacylglycerol analogue 1-oleoyl-2-acetyl-sn-glycerol (OAG) reversed the inhibitory effect of candesartan, while this rescue effect was prevented by the protein kinase C (PKC) inhibitor GF 109203X. Both candesartan and PKC inhibition caused increased G-actin levels, as determined by Western blotting of vessel lysates, supporting involvement of cytoskeletal remodelling. At the single vascular smooth muscle cell level, atomic force microscopy showed that cell swelling (stretch) with hypotonic buffer also caused thickening of cortical actin fibres and this was blocked by candesartan. Collectively, the present studies support growing evidence for novel modes of activation of the AT1 R in arterioles and suggest that mechanically activated AT1 R generates diacylglycerol, which in turn activates PKC which induces the actin cytoskeleton reorganization that is required for pressure-induced vasoconstriction.

Identification of nicotinamide phosphoribosyltransferase (NAMPT) inhibitors with no evidence of CYP3A4 time-dependent inhibition and improved aqueous solubility.

Herein we report the optimization efforts to ameliorate the potent CYP3A4 time-dependent inhibition (TDI) and low aqueous solubility exhibited by a previously identified lead compound from our NAMPT inhibitor program (1, GNE-617). Metabolite identification studies pinpointed the imidazopyridine moiety present in 1 as the likely source of the TDI signal, and replacement with other bicyclic systems was found to reduce or eliminate the TDI finding. A strategy of reducing the number of aromatic rings and/or lowering cLogD7.4 was then employed to significantly improve aqueous solubility. These efforts culminated in the discovery of 42, a compound with no evidence of TDI, improved aqueous solubility, and robust efficacy in tumor xenograft studies.

Fragment-based design of 3-aminopyridine-derived amides as potent inhibitors of human nicotinamide phosphoribosyltransferase (NAMPT).

The fragment-based identification of two novel and potent biochemical inhibitors of the nicotinamide phosphoribosyltransferase (NAMPT) enzyme is described. These compounds (51 and 63) incorporate an amide moiety derived from 3-aminopyridine, and are thus structurally distinct from other known anti-NAMPT agents. Each exhibits potent inhibition of NAMPT biochemical activity (IC50=19 and 15 nM, respectively) as well as robust antiproliferative properties in A2780 cell culture experiments (IC50=121 and 99 nM, respectively). However, additional biological studies indicate that only inhibitor 51 exerts its A2780 cell culture effects via a NAMPT-mediated mechanism. The crystal structures of both 51 and 63 in complex with NAMPT are also independently described.

Nonalloreactive T cells prevent donor lymphocyte infusion-induced graft-versus-host disease by controlling microbial stimuli.

In mice, graft-versus-host reactions, associated with powerful graft-versus-tumor effects, can be achieved without graft-versus-host disease (GVHD) by delayed administration of donor lymphocyte infusions (DLI) to established mixed chimeras. However, GVHD sometimes occurs after DLI in established mixed chimeric patients. In contrast to mice, in which T cell recovery from the thymus occurs prior to DLI administration, human T cell reconstitution following T cell-depleted hematopoietic cell transplantation is slow, resulting in lymphopenia at the time of DLI. We demonstrate in this study that T cell lymphopenia is an independent risk factor for GVHD following DLI in the absence of known inflammatory stimuli. DLI-induced GVHD was prevented in lymphopenic recipients by prior administration of a small number of nonalloreactive polyclonal T cells, insufficient to prevent lymphopenia-associated expansion of subsequently administered T cells, through a regulatory T cell-independent mechanism. GVHD was not inhibited by T cells with irrelevant specificity. Moreover, administration of antibiotics reduced the severity of GVHD in lymphopenic hosts. Accumulation of DLI-derived effector T cells and host hematopoietic cell elimination were markedly diminished by regulatory T cell-depleted, nonalloreactive T cells. Finally, thymectomized mixed chimeras showed increased GVHD following delayed DLI. Collectively, our data demonstrate that in the absence of known conditioning-induced inflammatory stimuli, T cell lymphopenia is a risk factor for GVHD in mixed chimeras receiving delayed DLI. Our data suggest that the predisposition to GVHD can at least in part be explained by the presence of occult inflammatory stimuli due to the absence of T cells to control microbial infections.

Effects of Bacillus licheniformis on growth performance, immune and antioxidant functions, and intestinal microbiota of broilers.

Bacillus licheniformis (BL) has been widely regarded as an important growth promoter in recent years. However, its usage in animal industry still needs more foundations. The aim of our study was to study the effects of BL on the growth performance, immunity, oxidative function and intestinal flora of broilers. A total of 760 one-day-old yellow-feathered broilers were randomly divided into 4 groups with 10 replicates per group and 19 broilers per replicate. The broilers in the control group (CON) were fed with basal diet. The treatment groups were supplemented with 250 mg/kg (BL250), 500 mg/kg (BL500) and 750 mg/kg (BL750) BL in the basal diet for 70 d. Results showed that BL groups significantly increased the body weight (BW) and average daily gain (ADG), decreased average daily feed intake (ADFI) and feed conversion ratio (FCR). In addition, the spleen and bursa indexes were higher in the BL groups than that in the CON group at d 70. BL supplementation also markedly increased the levels of immunoglobulins Y (IgY), IgA and anti-inflammatory interleukin 10 (IL-10), reduced the levels of proinflammatory IL-1ß, tumor necrosis factor α (TNF-α) and IL-2 in the serum at 70 d in a concentration-dependent manner. Besides, BL addition significantly increased the levels of series antioxidant enzymes including total antioxidant capacity (T-AOC), glutathione peroxidase (GPX), superoxide dismutase (SOD), and catalase (CAT), and decreased the level of malondialdehyde (MDA) in the serum. Moreover, BL groups showed an obvious increase of isobutyric acid markedly and BL500 group significantly promoted the level of isovaleric acid in cecal contents of broilers. Finally, microbial analysis showed that BL supplementation presented visual separations of microbial composition and increased the relative abundance of p_Proteobacteria, g_Elusimicrobium, and g_Parasutterella comparing with the CON group. Together, this study inferred that dietary BL supplementation improved the growth performance, immune and antioxidant functions, changed the intestinal microflora structure and metabolites of yellow-feathered broilers, which laid a good basis for the application of probiotics in the future.

LAG-3, TGF-ß, and cell-intrinsic PD-1 inhibitory pathways contribute to CD8 but not CD4 T-cell tolerance induced by allogeneic BMT with anti-CD40L.

Administration of a single dose of anti-CD40L mAb at the time of allogeneic BM transplantation tolerizes peripheral alloreactive T cells and permits establishment of mixed hematopoietic chimerism in mice. Once engrafted, mixed chimeras are systemically tolerant to donor Ags through a central deletion mechanism and will accept any donor organ indefinitely. We previously found that the PD-1/PD-L1 pathway is required for CD8 T-cell tolerance in this model. However, the cell population that must express PD-1 and the role of other inhibitory molecules were unknown. Here, we report that LAG-3 is required for long-term peripheral CD8 but not CD4 T-cell tolerance and that this requirement is CD8 cell-extrinsic. In contrast, adoptive transfer studies revealed a CD8 T cell-intrinsic requirement for CTLA4/B7.1/B7.2 and for PD-1 for CD8 T-cell tolerance induction. We also observed that both PD-L1 and PD-L2 are independently required on donor cells to achieve T-cell tolerance. Finally, we uncovered a requirement for TGF-ß signaling into T cells to achieve peripheral CD8 but not CD4 T-cell tolerance in this in vivo system.

Discovery of potent and efficacious urea-containing nicotinamide phosphoribosyltransferase (NAMPT) inhibitors with reduced CYP2C9 inhibition properties.

Potent, reversible inhibition of the cytochrome P450 CYP2C9 isoform was observed in a series of urea-containing nicotinamide phosphoribosyltransferase (NAMPT) inhibitors. This unwanted property was successfully removed from the described inhibitors through a combination of structure-based design and medicinal chemistry activities. An optimized compound which did not inhibit CYP2C9 exhibited potent anti-NAMPT activity (17; BC NAMPT IC50=3 nM; A2780 antiproliferative IC50=70 nM), good mouse PK properties, and was efficacious in an A2780 mouse xenograft model. The crystal structure of this compound in complex with the NAMPT protein is also described.

Human natural regulatory T cell development, suppressive function, and postthymic maturation in a humanized mouse model.

CD4(+) regulatory T cells (Tregs) control adaptive immune responses and promote self-tolerance. Various humanized mouse models have been developed in efforts to reproduce and study a human immune system. However, in models that require T cell differentiation in the recipient murine thymus, only low numbers of T cells populate the peripheral immune systems. T cells are positively selected by mouse MHC and therefore do not function well in an HLA-restricted manner. In contrast, cotransplantation of human fetal thymus/liver and i.v. injection of CD34(+) cells from the same donor achieves multilineage human lymphohematopoietic reconstitution, including dendritic cells and formation of secondary lymphoid organs, in NOD/SCID mice. Strong Ag-specific immune responses and homeostatic expansion of human T cells that are dependent on peripheral human APCs occur. We now demonstrate that FOXP3(+)Helios(+) "natural" Tregs develop normally in human fetal thymic grafts and are present in peripheral blood, spleen, and lymph nodes of these humanized mice. Humanized mice exhibit normal reversal of CD45 isoform expression in association with thymic egress, postthymic "naive" to "activated" phenotypic conversion, and suppressive function. These studies demonstrate the utility of this humanized mouse model for the study of human Treg ontogeny, immunobiology and therapy.

Trends in grassland science: Based on the shift analysis of research themes since the early 1900s.

Grasslands, one of the major terrestrial ecosystems, are essential for the maintenance of ecological and production functions; however, they are undergoing extensive degradation. The development and cutting-edge explorations in grassland science are critical to addressing challenges such as climate change and the increasing influence of human activities. To identify research trends in grassland science, latent Dirichlet allocation (LDA) topic modelling was used to conduct an automated content analysis on 123,829 papers available on Web of Science Core Collection from 1900 to 2020. Results from this analysis showed that grassland research has become increasing multidisciplinary, accompanied by a pronounced reduction in the relative frequency of traditional production-oriented research and an increase in the themes focusing on ecological functions and modern technologies. Changes in research activities have been uneven globally, with a significant increase in the number of publications in China and Brazil, which probably reflects an increased support from various governmental agencies in these countries. Additionally, in 2019, China surpassed the United States in terms of the total number of publications. Further, this study identified important topics and emerging challenges in grassland research, such as biodiversity conservation, climate changes, and genetic considerations. Comprehensive improvement of education, research, global cooperation, and funding strategies will be necessary to promote grassland science research on frontier themes and to effectively address the social and environmental challenges in the new era.

Research on IMU Calibration Model Based on Polar Decomposition.

As an important deterministic error of the inertial measurement unit (IMU), the installation error has a serious impact on the navigation accuracy of the strapdown inertial navigation system (SINS). The impact becomes more severe in a highly dynamic application environment. This paper proposes a new IMU calibration model based on polar decomposition. Using the new model, the installation error is decomposed into a nonorthogonal error and a misalignment error. The compensation of the IMU calibration model is decomposed into two steps. First, the nonorthogonal error is compensated, and then the misalignment error is compensated. Based on the proposed IMU calibration model, we used a three-axis turntable to calibrate three sets of strapdown inertial navigation systems (SINS). The experimental results show that the misalignment errors are larger than the nonorthogonal errors. Based on the experimental results, this paper proposes a new method to simplify the installation error. This simplified method defines the installation error matrix as an antisymmetric matrix composed of three misalignment errors. The navigation errors caused by the proposed simplified calibration model are compared with the navigation errors caused by the traditional simplified calibration model. The 48-h navigation experiment results show that the proposed simplified calibration model is superior to the traditional simplified calibration model in attitude accuracy, velocity accuracy, and position accuracy.