Chen Etal Research Articles

The Gut Feeling: GPCRs Enlighten the Way

Host-microbiome interactions affect host physiology, but the underlying mechanisms are not well understood. Recent papers from Chen etal. (2019) and Colosimo etal. (2019) in this issue of Cell Host & Microbe demonstrate that metabolites produced by several members of the gut microbiota can efficiently activate host G protein-coupled receptors and influence host physiology.

Dependence of the viewing angle control property of a guest-host liquid crystal cell on the extinction coefficient of the mixture.

The theoretical prediction of a display viewing angle control using a guest-host (GH) liquid crystal (LC) cell has been reported by Chen etal. [Jpn. J. Appl. Phys.48, 062401 (2009)JJAPA50021-492210.1143/JJAP.48.062401]. We experimentally confirmed the viewing angle control property of the GH cell and also investigated its dependence on the extinction coefficient of the GH mixture. The GH cell with a negative dielectric anisotropy and a vertical orientation was attached on front of the display panel, resulting in narrow viewing (NV) property at the field-off state. The GH molecules were switched to a planar orientation, which is also orthogonal to the polarization direction of light at the field-on state, showing wide viewing (WV) property. We varied the concentration of a guest dichroic dye in a host LC and measured the extinction coefficients of the mixtures. We simulated the viewing control property using the measured extinction coefficients and found that the horizontal viewing angle can be controlled using the GH cell, but the vertical viewing angle cannot be controlled. Then, we experimentally confirmed the horizontal viewing angle control using the GH cell. The extinction between the NV and the WV states was increased with a greater extinction coefficient of the GH molecules, but the transmittance was decreased.

Dangerous γδ T cells in aged mice.

Progressive susceptibility to tumors and infectious diseases in the elderly are a serious threat to public health in aging societies. For this reason, there is growing interest in mechanisms and predictive biomarkers that accompany and potentially cause this process. In this issue of EMBO Reports, Chen etal [1] report the surprising finding that a specific subset of γδ T cells with very limited clonal diversity strongly expands in lymph nodes of aging mice. These T cells uniformly express a T-cell receptor (TCR) composed of a Vγ6 and a Vδ1 chain and show an effector T-cell phenotype characterized by the swift production of the pro-inflammatory cytokine interleukin-17 (IL-17) upon exvivo stimulation (γδT17 cells). Since γδT17 cells are suspected to be pro-tumorigenic [2], the authors next compared how mice of different age coped with an experimental lung cancer challenge and found impaired anti-tumor responses in old mice. Based on these observations, they propose a link between changes of the composition of γδ T cells in the aging lymph nodes and increased risk of cancer development in aged mice.

On the Right Track: Meningeal Lymphatics Guide Angiogenesis during Tissue Repair in the Brain

Recent studies of brain meningeal lymphatic endothelial cells in mouse and zebrafish have raised interest in their function. In this issue of Developmental Cell, Chen etal. (2019) reveal new developmental roles for these cells in facilitating tissue repair and guiding vascular re-growth in the central nervous system.

Unlocking the Dangers of a Stiffening Brain

Mechanical cues regulate neuronal function and reactivity of glial cells, the origin of gliomas. In this issue of Neuron, Chen etal. (2018) uncover a feedforward loop mediated by the mechanosensitive ion channel Piezo1 and tissue stiffness that drives glioma aggression.

Remembering a Bad Taste

The phenomenon of conditioned taste aversion (CTA) is generated after ingestion of a specific food is associated with an adverse outcome, i.e., sickness. In this issue of Neuron, Chen etal. (2018) interrogate the pivotal role of PBNCGRP neurons in both the acquisition and the expression of CTA.

Tunable Quantum Spin Liquidity in the 1/6th-Filled Breathing Kagome Lattice.

We present measurements on a series of materials, Li_{2}In_{1-x}Sc_{x}Mo_{3}O_{8}, that can be described as a 1/6th-filled breathing kagome lattice. Substituting Sc for In generates chemical pressure which alters the breathing parameter nonmonotonically. Muon spin rotation experiments show that this chemical pressure tunes the system from antiferromagnetic long range order to a quantum spin liquid phase. A strong correlation with the breathing parameter implies that it is the dominant parameter controlling the level of magnetic frustration, with increased kagome symmetry generating the quantum spin liquid phase. Magnetic susceptibility measurements suggest that this is related to distinct types of charge order induced by changes in lattice symmetry, in line with the theory of Chen etal. [Phys. Rev. B 93, 245134 (2016)PRBMDO2469-995010.1103/PhysRevB.93.245134]. The specific heat for samples at intermediate Sc concentration, which have the minimum breathing parameter, show consistency with the predicted U(1) quantum spin liquid.

Not all vascular smooth muscle cell exosomes calcify equally in chronic kidney disease

Prevention of medial calcification in patients with chronic kidney disease requires the maintenance of vascular smooth muscle cell fitness. To preserve viability under chronic kidney disease-induced stress, vascular smooth muscle cells increase exosome formation and release, but the result is aggravated pathological calcification. Now Chen etal. report that microvesicles from calcifying vascular smooth muscle cells may propagate procalcifying signals to normal vascular smooth muscle cells. To help design effective strategies to impair procalcifying cell-to-cell communication, this commentary updates the current understanding of the main regulators of microvesicle/exosome biogenesis and secretion.

Partial entropic stabilization of lattice Boltzmann magnetohydrodynamics.

The entropic lattice Boltzmann algorithm of Karlin etal. [Phys. Rev. E 90, 031302 (2014)PLEEE81539-375510.1103/PhysRevE.90.031302] is partially extended to magnetohydrodynamics, based on the Dellar model of introducing a vector distribution for the magnetic field. This entropic ansatz is now applied only to the scalar particle distribution function so as to permit the many problems entailing magnetic field reversal. A 9-bit lattice is employed for both particle and magnetic distributions for our two-dimensional simulations. The entropic ansatz is benchmarked against our earlier multiple relaxation lattice-Boltzmann model for the Kelvin-Helmholtz instability in a magnetized jet. Other two-dimensional simulations are performed and compared to results determined by more standard direct algorithms: in particular the switch over between the Kelvin-Helmholtz or tearing mode instability of Chen etal. [J. Geophys. Res.: Space Phys. 102, 151 (1997)JGREA20148-022710.1029/96JA03144], and the generalized Orszag-Tang vortex model of Biskamp-Welter [Phys. Fluids B 1, 1964 (1989)PFBPEI0899-822110.1063/1.859060]. Very good results are achieved.

Saving Stem Cells after Stress

Inflammatory signals can activate hematopoietic stem cells (HSCs), but how HSCs regain quiescence after stress is unclear. In this issue of Cell Stem Cell, Chen etal. (2017) delineate an elegant histamine-dependent feedback mechanism through which myeloid bone marrow cells restore quiescence of myeloid-biased HSCs, with implications for blood disorders, aging, and immunity.

Partial inertia induces additional phase transition in the majority vote model.

Explosive (i.e., discontinuous) transitions have aroused great interest by manifesting in distinct systems, such as synchronization in coupled oscillators, percolation regime, absorbing phase transitions, and more recently, the majority-vote model with inertia. In the latter, the model rules are slightly modified by the inclusion of a term depending on the local spin (an inertial term). In such a case, Chen etal. [Phys Rev. E 95, 042304 (2017)2470-004510.1103/PhysRevE.95.042304] have found that relevant inertia changes the nature of the phase transition in complex networks, from continuous to discontinuous. Here we give a further step by embedding inertia only in vertices with degree larger than a threshold value 〈k〉k^{*}, 〈k〉 being the mean system degree and k^{*} the fraction restriction. Our results, from mean-field analysis and extensive numerical simulations, reveal that an explosive transition is presented in both homogeneous and heterogeneous structures for small and intermediate k^{*}'s. Otherwise, a large restriction can sustain a discontinuous transition only in the heterogeneous case. This shares some similarities with recent results for the Kuramoto model [Phys. Rev. E 91, 022818 (2015)PLEEE81539-375510.1103/PhysRevE.91.022818]. Surprisingly, intermediate restriction and large inertia are responsible for the emergence of an extra phase, in which the system is partially synchronized and the classification of phase transition depends on the inertia and the lattice topology. In this case, the system exhibits two phase transitions.

Epigenetic Control of NRF2-Directed Cellular Antioxidant Status in Dictating Life-Death Decisions

In this issue of Molecular Cell, Chen etal. (2017) demonstrate that the tumor suppressor protein ARF sensitizes cancer cells to programmed death through a surprising mechanism: ARF physically interacts with and antagonizes activation by acetylation of the master redox regulator NRF2, providing an unusual mode of posttranslational NRF2 regulation.

Antiviral Immunity and Circular RNA: No End in Sight

In this issue of Molecular Cell, two papers by Chen etal. (2017) and Li etal. (2017) describe new insights into circRNA biogenesis and function, connecting circRNAs to innate immune pathways.

Paradoxical Effects of MLL Paralogs in MLL-Rearranged Leukemia

Conflicting data exist on the requirement for wild-type MLL1 in MLL-rearranged leukemia. In this issue of Cancer Cell, Chen etal. describe complementary approaches demonstrating that MLL1 is dispensable for MLL-fusion-mediated leukemogenesis. They also observe an unexpected role for MLL2 in MLL-rearranged leukemia cells and identify potential therapeutic targets.

Bacteria and the Fate of Estrogen in the Environment

In this issue of Cell Chemical Biology, Chen etal. (2017) report that 4-hydroxyestrone and pyridinestroneacid are intermediates in the 4,5-seco pathway of aerobic estrogen degradation by the bacteriumSphingomonas. The authors identify a gene for 4-hydroxyestrone 4,5-dioxygenase and find it tobe widely distributed in diverse proteobacteria, suggesting that this pathway is environmentally significant.

Down the Rabbit Hole of Single-Cell Genome Analysis

Chen etal. (2017) demonstrate whole-genome amplification of single-cell genomic DNA using linear nucleic acid amplification. This provides reliable single-nucleotide variation (SNV) detection across the single-cell genome, facilitating an understanding of cell-to-cell similarities and distinctions.

Ready, Steady, Go! Imaging Cortical Activity during Movement Planning and Execution

In this issue of Neuron, Chen etal. (2017) examine premotor activity representing motor planning, Allen etal. (2017) observe the global representation of goal-directed movement on the cortical network, and Makino etal. (2017) track changes in such dynamics throughout learning.

Joining Forces: Bmi1 Inhibition and Cisplatin Curb Squamous Carcinogenesis

Head and neck squamous cell carcinomas (HNSCCs) are refractory to therapeutic interventions. Chen etal. (2017) show that mouse and human HNSCCs and their metastases depend on Bmi1-expressing cancer stem cells and AP1 signaling and that simultaneously inhibiting Bmi1 or AP1, combined with Cisplatin, reduces tumor growth effectively in preclinical models.

Interleukin-17: Why the Worms Squirm

IL-17 is a cytokine known primarily for its role in inflammation. In a recent issue of Nature, Chen etal. (2017) demonstrate that IL-17 plays a neuromodulatory role in Caenorhabditis elegans by acting directly on neurons to amplify neuronal responses to stimuli and produce changes in animal behavior.

Warfare between Host Immunity and Bacterial Weapons

Bacterial pathogens deploy protein secretion systems to facilitate infection and colonization of their hosts. Inthis issue of Cell Host & Microbe, Chen etal. (2017) report a new role for a type VI secretion effector in promoting bacterial colonization by preventing inflammasome activation induced by a type III secretion system.