A multimodal zebrafish developmental atlas reveals the state-transition dynamics of late-vertebrate pluripotent axial progenitors.

Elucidating organismal developmental processes requires a comprehensive understanding of cellular lineages in the spatial, temporal, and molecular domains. In this study, we introduce Zebrahub, a dynamic atlas of zebrafish embryonic development that integrates single-cell sequencing time course data with lineage reconstructions facilitated by light-sheet microscopy. This atlas offers high-resolution and in-depth molecular insights into zebrafish development, achieved through the sequencing of individual embryos across ten developmental stages, complemented by reconstructions of cellular trajectories. Zebrahub also incorporates an interactive tool to navigate the complex cellular flows and lineages derived from light-sheet microscopy data, enabling in silico fate-mapping experiments. To demonstrate the versatility of our multimodal resource, we utilize Zebrahub to provide fresh insights into the pluripotency of neuro-mesodermal progenitors (NMPs) and the origins of a joint kidney-hemangioblast progenitor population.

Facile discovery of surrogate cytokine agonists.

Cytokines are powerful immune modulators that initiate signaling through receptor dimerization, but natural cytokines have structural limitations as therapeutics. We present a strategy to discover cytokine surrogate agonists by using modular ligands that exploit induced proximity and receptor dimer geometry as pharmacological metrics amenable to high-throughput screening. Using VHH and scFv to human interleukin-2/15, type-I interferon, and interleukin-10 receptors, we generated combinatorial matrices of single-chain bispecific ligands that exhibited diverse spectrums of functional activities, including potent inhibition of SARS-CoV-2 by surrogate interferons. Crystal structures of IL-2R:VHH complexes revealed that variation in receptor dimer geometries resulted in functionally diverse signaling outputs. This modular platform enabled engineering of surrogate ligands that compelled assembly of an IL-2R/IL-10R heterodimer, which does not naturally exist, that signaled through pSTAT5 on T and natural killer (NK) cells. This "cytokine med-chem" approach, rooted in principles of induced proximity, is generalizable for discovery of diversified agonists for many ligand-receptor systems.

T cell receptor and cytokine signal integration in CD8+ T cells is mediated by the protein Themis.

T cell homeostasis and functional responsiveness require signals from self-peptide-major histocompatibility complex (self-pMHC) and cytokines, but the mechanisms controlling this signal integration are unknown. Using a conditional deletion of the T cell lineage-specific protein Themis, we show that Themis is required for the maintenance of peripheral CD8+ T cells and for proliferative CD8+ T cell responses to low-affinity pMHC aided by cytokines. Themis-deficient peripheral T cells show a phenotype indicative of reduced tonic signaling from self-pMHC, strongly suggesting that Themis is a positive regulator of T cell receptor signal strength in response to low-affinity self-pMHC in peripheral T cells. Signals from low-affinity pMHC and cytokines synergistically induce phosphorylation of the kinase Akt, metabolic changes and c-Myc transcription factor induction in CD8+ T cells only in the presence of Themis. This function of Themis is mediated through Shp1 phosphatase, as peripheral Themis and Shp1 double deletion rescues the peripheral CD8+ T cell maintenance.

Flatband λ-Ti3O5 towards extraordinary solar steam generation.

Solar steam interfacial evaporation represents a promising strategy for seawater desalination and wastewater purification owing to its environmentally friendly character1-3. To improve the solar-to-steam generation, most previous efforts have focused on effectively harvesting solar energy over the full solar spectrum4-7. However, the importance of tuning joint densities of states in enhancing solar absorption of photothermal materials is less emphasized. Here we propose a route to greatly elevate joint densities of states by introducing a flat-band electronic structure. Our study reveals that metallic λ-Ti3O5 powders show a high solar absorptivity of 96.4% due to Ti-Ti dimer-induced flat bands around the Fermi level. By incorporating them into three-dimensional porous hydrogel-based evaporators with a conical cavity, an unprecedentedly high evaporation rate of roughly 6.09 kilograms per square metre per hour is achieved for 3.5 weight percent saline water under 1 sun of irradiation without salt precipitation. Fundamentally, the Ti-Ti dimers and U-shaped groove structure exposed on the λ-Ti3O5 surface facilitate the dissociation of adsorbed water molecules and benefit the interfacial water evaporation in the form of small clusters. The present work highlights the crucial roles of Ti-Ti dimer-induced flat bands in enchaining solar absorption and peculiar U-shaped grooves in promoting water dissociation, offering insights into access to cost-effective solar-to-steam generation.

Autoimmunity-associated T cell receptors recognize HLA-B*27-bound peptides.

Human leucocyte antigen B*27 (HLA-B*27) is strongly associated with inflammatory diseases of the spine and pelvis (for example, ankylosing spondylitis (AS)) and the eye (that is, acute anterior uveitis (AAU))1. How HLA-B*27 facilitates disease remains unknown, but one possible mechanism could involve presentation of pathogenic peptides to CD8+ T cells. Here we isolated orphan T cell receptors (TCRs) expressing a disease-associated public ß-chain variable region-complementary-determining region 3ß (BV9-CDR3ß) motif2-4 from blood and synovial fluid T cells from individuals with AS and from the eye in individuals with AAU. These TCRs showed consistent α-chain variable region (AV21) chain pairing and were clonally expanded in the joint and eye. We used HLA-B*27:05 yeast display peptide libraries to identify shared self-peptides and microbial peptides that activated the AS- and AAU-derived TCRs. Structural analysis revealed that TCR cross-reactivity for peptide-MHC was rooted in a shared binding motif present in both self-antigens and microbial antigens that engages the BV9-CDR3ß TCRs. These findings support the hypothesis that microbial antigens and self-antigens could play a pathogenic role in HLA-B*27-associated disease.

NSUN5/TET2-directed chromatin-associated RNA modification of 5-methylcytosine to 5-hydroxymethylcytosine governs glioma immune evasion.

Malignant glioma exhibits immune evasion characterized by highly expressing the immune checkpoint CD47. RNA 5-methylcytosine(m5C) modification plays a pivotal role in tumor pathogenesis. However, the mechanism underlying m5C-modified RNA metabolism remains unclear, as does the contribution of m5C-modified RNA to the glioma immune microenvironment. In this study, we demonstrate that the canonical 28SrRNA methyltransferase NSUN5 down-regulates ß-catenin by promoting the degradation of its mRNA, leading to enhanced phagocytosis of tumor-associated macrophages (TAMs). Specifically, the NSUN5-induced suppression of ß-catenin relies on its methyltransferase activity mediated by cysteine 359 (C359) and is not influenced by its localization in the nucleolus. Intriguingly, NSUN5 directly interacts with and deposits m5C on CTNNB1 caRNA (chromatin-associated RNA). NSUN5-induced recruitment of TET2 to chromatin is independent of its methyltransferase activity. The m5C modification on caRNA is subsequently oxidized into 5-hydroxymethylcytosine (5hmC) by TET2, which is dependent on its binding affinity for Fe2+ and α-KG. Furthermore, NSUN5 enhances the chromatin recruitment of RBFOX2 which acts as a 5hmC-specific reader to recognize and facilitate the degradation of 5hmC caRNA. Notably, hmeRIP-seq analysis reveals numerous mRNA substrates of NSUN5 that potentially undergo this mode of metabolism. In addition, NSUN5 is epigenetically suppressed by DNA methylation and is negatively correlated with IDH1-R132H mutation in glioma patients. Importantly, pharmacological blockage of DNA methylation or IDH1-R132H mutant and CD47/SIRPα signaling synergistically enhances TAM-based phagocytosis and glioma elimination in vivo. Our findings unveil a general mechanism by which NSUN5/TET2/RBFOX2 signaling regulates RNA metabolism and highlight NSUN5 targeting as a potential strategy for glioma immune therapy.

Fixed-duration pirtobrutinib plus venetoclax with or without rituximab in relapsed/refractory CLL: the phase 1b BRUIN trial.

ABSTRACT: Pirtobrutinib is a highly selective, noncovalent (reversible) Bruton tyrosine kinase inhibitor (BTKi). Patients with relapsed or refractory (R/R) chronic lymphocytic leukemia (CLL) were treated with fixed-duration pirtobrutinib plus venetoclax (PV) or pirtobrutinib plus venetoclax and rituximab (PVR) in this phase 1b trial. Prior covalent BTKi therapy was allowed, but not prior treatment with venetoclax. Patients were assigned to receive PV (n = 15) or PVR (n = 10) for 25 cycles. Most patients (68%) had received prior covalent BTKi therapy. At the data cutoff date, the median time on study was 27.0 months for PV and 23.3 months for PVR. Overall response rates were 93.3% (95% confidence interval [CI], 68.1-99.8) for PV and 100% (95% CI, 69.2-100.0) for PVR, with 10 complete responses (PV: 7; PVR: 3). After 12 cycles of treatment, 85.7% (95% CI, 57.2-98.2) of PV and 90.0% (95% CI, 55.5-99.7) of PVR patients achieved undetectable minimal residual disease (<10-4) in peripheral blood. Progression-free survival at 18 months was 92.9% (95% CI, 59.1-99.0) for PV patients and 80.0% (95% CI, 40.9-94.6) for PVR patients. No dose-limiting toxicities were observed during the 5-week assessment period. The most common grade ≥3 adverse events (AEs) for all patients included neutropenia (52%) and anemia (16%). AEs led to dose reduction in 3 patients and discontinuation in 2. In conclusion, fixed-duration PV or PVR was well tolerated and had promising efficacy in patients with R/R CLL, including patients previously treated with a covalent BTKi. This trial was registered at www.clinicaltrials.gov as #NCT03740529.

Zebrafish Mbd5 binds to RNA m5C and regulates histone deubiquitylation and gene expression in development metabolism and behavior.

Complex biological processes are regulated by both genetic and epigenetic programs. One class of epigenetic modifications is methylation. Evolutionarily conserved methyl-CpG-binding domain (MBD)-containing proteins are known as readers of DNA methylation. MBD5 is linked to multiple human diseases but its mechanism of action remains unclear. Here we report that the zebrafish Mbd5 does not bind to methylated DNA; but rather, it directly binds to 5-methylcytosine (m5C)-modified mRNAs and regulates embryonic development, erythrocyte differentiation, iron metabolism, and behavior. We further show that Mbd5 facilitates removal of the monoubiquitin mark at histone H2A-K119 through an interaction with the Polycomb repressive deubiquitinase (PR-DUB) complex in vivo. The direct target genes of Mbd5 are enriched with both RNA m5C and H2A-K119 ubiquitylation signals. Together, we propose that zebrafish MBD5 is an RNA m5C reader that potentially links RNA methylation to histone modification and in turn transcription regulation in vivo.

USP28 Serves as a Key Suppressor of Mitochondrial Morphofunctional Defects and Cardiac Dysfunction in the Diabetic Heart.

BACKGROUND: The majority of people with diabetes are susceptible to cardiac dysfunction and heart failure, and conventional drug therapy cannot correct diabetic cardiomyopathy progression. Herein, we assessed the potential role and therapeutic value of USP28 (ubiquitin-specific protease 28) on the metabolic vulnerability of diabetic cardiomyopathy. METHODS: The type 2 diabetes mouse model was established using db/db leptin receptor-deficient mice and high-fat diet/streptozotocin-induced mice. Cardiac-specific knockout of USP28 in the db/db background mice was generated by crossbreeding db/m and Myh6-Cre+/USP28fl/fl mice. Recombinant adeno-associated virus serotype 9 carrying USP28 under cardiac troponin T promoter was injected into db/db mice. High glucose plus palmitic acid-incubated neonatal rat ventricular myocytes and human induced pluripotent stem cell-derived cardiomyocytes were used to imitate diabetic cardiomyopathy in vitro. The molecular mechanism was explored through RNA sequencing, immunoprecipitation and mass spectrometry analysis, protein pull-down, chromatin immunoprecipitation sequencing, and chromatin immunoprecipitation assay. RESULTS: Microarray profiling of the UPS (ubiquitin-proteasome system) on the basis of db/db mouse hearts and diabetic patients' hearts demonstrated that the diabetic ventricle presented a significant reduction in USP28 expression. Diabetic Myh6-Cre+/USP28fl/fl mice exhibited more severe progressive cardiac dysfunction, lipid accumulation, and mitochondrial disarrangement, compared with their controls. On the other hand, USP28 overexpression improved systolic and diastolic dysfunction and ameliorated cardiac hypertrophy and fibrosis in the diabetic heart. Adeno-associated virus serotype 9-USP28 diabetic mice also exhibited less lipid storage, reduced reactive oxygen species formation, and mitochondrial impairment in heart tissues than adeno-associated virus serotype 9-null diabetic mice. As a result, USP28 overexpression attenuated cardiac remodeling and dysfunction, lipid accumulation, and mitochondrial impairment in high-fat diet/streptozotocin-induced type 2 diabetes mice. These results were also confirmed in neonatal rat ventricular myocytes and human induced pluripotent stem cell-derived cardiomyocytes. RNA sequencing, immunoprecipitation and mass spectrometry analysis, chromatin immunoprecipitation assays, chromatin immunoprecipitation sequencing, and protein pull-down assay mechanistically revealed that USP28 directly interacted with PPARα (peroxisome proliferator-activated receptor α), deubiquitinating and stabilizing PPARα (Lys152) to promote Mfn2 (mitofusin 2) transcription, thereby impeding mitochondrial morphofunctional defects. However, such cardioprotective benefits of USP28 were largely abrogated in db/db mice with PPARα deletion and conditional loss-of-function of Mfn2. CONCLUSIONS: Our findings provide a USP28-modulated mitochondria homeostasis mechanism that involves the PPARα-Mfn2 axis in diabetic hearts, suggesting that USP28 activation or adeno-associated virus therapy targeting USP28 represents a potential therapeutic strategy for diabetic cardiomyopathy.

A bead-based method for high-throughput mapping of the sequence- and force-dependence of T cell activation.

Adaptive immunity relies on T lymphocytes that use αß T cell receptors (TCRs) to discriminate among peptides presented by major histocompatibility complex molecules (pMHCs). Identifying pMHCs capable of inducing robust T cell responses will not only enable a deeper understanding of the mechanisms governing immune responses but could also have broad applications in diagnosis and treatment. T cell recognition of sparse antigenic pMHCs in vivo relies on biomechanical forces. However, in vitro screening methods test potential pMHCs without force and often at high (nonphysiological) pMHC densities and thus fail to predict potent agonists in vivo. Here, we present a technology termed BATTLES (biomechanically assisted T cell triggering for large-scale exogenous-pMHC screening) that uses biomechanical force to initiate T cell triggering for peptides and cells in parallel. BATTLES displays candidate pMHCs on spectrally encoded beads composed of a thermo-responsive polymer capable of applying shear loads to T cells, facilitating exploration of the force- and sequence-dependent landscape of T cell responses. BATTLES can be used to explore basic T cell mechanobiology and T cell-based immunotherapies.

DaXi-high-resolution, large imaging volume and multi-view single-objective light-sheet microscopy.

The promise of single-objective light-sheet microscopy is to combine the convenience of standard single-objective microscopes with the speed, coverage, resolution and gentleness of light-sheet microscopes. We present DaXi, a single-objective light-sheet microscope design based on oblique plane illumination that achieves: (1) a wider field of view and high-resolution imaging via a custom remote focusing objective; (2) fast volumetric imaging over larger volumes without compromising image quality or necessitating tiled acquisition; (3) fuller image coverage for large samples via multi-view imaging and (4) higher throughput multi-well imaging via remote coverslip placement. Our instrument achieves a resolution of 450 nm laterally and 2 µm axially over an imaging volume of 3,000 × 800 × 300 µm. We demonstrate the speed, field of view, resolution and versatility of our instrument by imaging various systems, including Drosophila egg chamber development, zebrafish whole-brain activity and zebrafish embryonic development - up to nine embryos at a time.

A zebrafish NLRX1 isoform downregulates fish IFN responses by targeting the adaptor STING.

In mammals, NLRX1 is a unique member of the nucleotide-binding domain and leucine-rich repeat (NLR) family showing an ability to negatively regulate IFN antiviral immunity. Intron-containing genes, including NLRX1, have more than one transcript due to alternative splicing; however, little is known about the function of its splicing variants. Here, we identified a transcript variant of NLRX1 in zebrafish (Danio rerio), termed NLRX1-tv4, as a negative regulator of fish IFN response. Zebrafish NLRX1-tv4 was slightly induced by viral infection, with an expression pattern similar to the full-length NLRX1. Despite the lack of an N-terminal domain that exists in the full-length NLRX1, overexpression of NLRX1-tv4 still impaired fish IFN antiviral response and promoted viral replication in fish cells, similar to the full-length NLRX1. Mechanistically, NLRX1-tv4 targeted STING for proteasome-dependent protein degradation by recruiting an E3 ubiquitin ligase RNF5 to drive the K48-linked ubiquitination, eventually downregulating the IFN antiviral response. Mapping of NLRX1-tv4 domains showed that its N-terminal and C-terminal regions exhibited a similar potential to inhibit STING-mediated IFN antiviral response. Our findings reveal that like the full-length NLRX1, zebrafish NLRX-tv4 functions as an inhibitor to shape fish IFN antiviral response.IMPORTANCEIn this study, we demonstrate that a transcript variant of zebrafish NLRX1, termed NLRX1-tv4, downregulates fish IFN response and promotes virus replication by targeting STING for protein degradation and impairing the interaction of STING and TBK1 and that its N- and C-terminus exhibit a similar inhibitory potential. Our results are helpful in clarifying the current contradictory understanding of structure and function of vertebrate NLRX1s.

Membrane-Localized Orientation of NONPHOTOTROPIC HYPOCOTYL3 Affects the Necessity of Its Phosphorylation for Phototropism.

NONPHOTOTROPIC HYPOCOTYL3 (NPH3) is a key regulator of hypocotyl phototropism under both low- and high-intensity blue light (LBL/HBL), mediating phototropin1 (phot1) and phot2 signaling. NPH3 undergoes dephosphorylation and is released from the plasma membrane (PM) upon blue light irradiation. However, how its phosphorylation status and PM localization mediate phot1 and phot2 signaling in Arabidopsis (Arabidopsis thaliana) remains elusive. In this study, we found that fusing NPH3 with GFP at its C terminus (N3G) impaired its release from the PM, a defect exacerbated by a phosphorylation-deficient mutation, resulting in a dephosphorylated NPH3-GFP (N3AG). Unlike N3G, transgenic lines expressing N3AG exhibited defective hypocotyl phototropism under HBL, which could be rescued by myristoylation at the N-terminus of N3AG (mN3AG), indicating that NPH3 phosphorylation is not essential for HBL-induced phototropic responses when it is artificially anchored at the PM via its N terminus. Furthermore, genetic analysis revealed that N3AG anchored to the PM by its N terminus (as in mN3AG) only rescues phot1-mediated HBL responses, which require RPT2. However, N3AG failed to regulate phot2-mediated HBL signaling, regardless of its PM orientation. Taken together, our results revealed that NPH3 phosphorylation is essential for phot2-mediated hypocotyl phototropism under HBL, but is not required for phot1-mediated HBL signaling when the NPH3 N terminus is PM-anchored.

Maize requires arogenate dehydratase 2 for resistance to Ustilago maydis and plant development.

Maize (Zea mays) smut is a common biotrophic fungal disease caused by Ustilago maydis and leads to low maize yield. Maize resistance to U. maydis is a quantitative trait. However, the molecular mechanism underlying the resistance of maize to U. maydis is poorly understood. Here, we reported that a maize mutant caused by a single gene mutation exhibited defects in both fungal resistance and plant development. maize mutant highly susceptible to U. maydis (mmsu) with a dwarf phenotype forms tumors in the ear. A map-based cloning and allelism test demonstrated that 1 gene encoding a putative arogenate dehydratase/prephenate dehydratase (ADT/PDT) is responsible for the phenotypes of the mmsu and was designated as ZmADT2. Combined transcriptomic and metabolomic analyses revealed that mmsu had substantial differences in multiple metabolic pathways in response to U. maydis infection compared with the wild type. Disruption of ZmADT2 caused damage to the chloroplast ultrastructure and function, metabolic flux redirection, and reduced the amounts of salicylic acid (SA) and lignin, leading to susceptibility to U. maydis and dwarf phenotype. These results suggested that ZmADT2 is required for maintaining metabolic flux, as well as resistance to U. maydis and plant development in maize. Meanwhile, our findings provided insights into the maize response mechanism to U. maydis infection.

TRANSPARENT TESTA GLABRA1 regulates high-intensity blue light-induced phototropism by reducing CRYPTOCHROME1 levels.

The asymmetrical distribution of auxin supports high intensity blue light (HBL)-mediated phototropism. Flavonoids, secondary metabolites induced by blue light and TRANSPARENT TESTA GLABRA1 (TTG1), alter auxin transport. However, the role of TTG1 in HBL-induced phototropism in Arabidopsis (Arabidopsis thaliana) remains unclear. We found that TTG1 regulates HBL-mediated phototropism. HBL-induced degradation of CRYPTOCHROME 1 (CRY1) was repressed in ttg1-1, and depletion of CRY1 rescued the phototropic defects of the ttg1-1 mutant. Moreover, overexpression of CRY1 in a cry1 mutant background led to phototropic defects in response to HBL. These results indicated that CRY1 is involved in the regulation of TTG1-mediated phototropism in response to HBL. Further investigation showed that TTG1 physically interacts with CRY1 via its N-terminus and that the added TTG1 promotes the dimerization of CRY1. The interaction between TTG1 and CRY1 may promote HBL-mediated degradation of CRY1. TTG1 also physically interacted with blue light inhibitor of cryptochrome 1 (BIC1) and Light-Response Bric-a-Brack/Tramtrack/Broad 2 (LRB2), and these interactions either inhibited or promoted their interaction with CRY1. Exogenous gibberellins (GA) and auxins, two key plant hormones that crosstalk with CRY1, may confer the recovery of phototropic defects in the ttg1-1 mutant and CRY1-overexpressing plants. Our results revealed that TTG1 participates in the regulation of HBL-induced phototropism by modulating CRY1 levels, which are coordinated with GA or IAA signaling.

N6-methyladenosine transcriptome-wide profiles of maize kernel development.

Maize (Zea mays L.) kernel development is a complex and dynamic process involving cell division and differentiation, into a variety of cell types. Epigenetic modifications, including DNA methylation, play a pivotal role in regulating this process. N6-methyladenosine modification is a universal and dynamic post-transcriptional epigenetic modification that is involved in the regulation of plant development. However, the role of N6-methyladenosine in maize kernel development remains unknown. In this study, we have constructed transcriptome-wide profiles for maize kernels at various stages of early development. Utilizing a combination of MeRIP-seq and RNA-seq analysis, we identified a total of 11,170, 10,973, 11,094, 11,990, 12,203 and 10,893 N6-methyladenosine peaks in maize kernels at 0, 2, 4, 6, 8, and 12 days after pollination, respectively. These N6-methyladenosine modifications were primarily deposited at the 3'-UTRs and were associated with the conserved motif-UGUACA. Additionally, we found that conserved N6-methyladenosine modification are involved in the regulation of genes that are ubiquitously expressed during kernel development. Further analysis revealed that N6-methyladenosine peak intensity was negatively correlated with the mRNA abundance of these ubiquitously expressed genes. Meanwhile, we employed phylogenetic analysis to predict potential regulatory proteins involved in maize kernels development and identified several that participate in the regulation of N6-methyladenosine modifications. Collectively, our results suggest the existence of a novel post-transcriptional epigenetic modification mechanism involved in the regulation of maize kernels development, thereby providing a novel perspective for maize molecular breeding.

A nanopore-based cucumber genome assembly reveals structural variations at two QTLs controlling hypocotyl elongation.

The Xishuangbanna (XIS) cucumber (Cucumis sativus var. xishuangbannanesis) is a semiwild variety that has many distinct agronomic traits. Here, long reads generated by Nanopore sequencing technology helped assembling a high-quality genome (contig N50 = 8.7 Mb) of landrace XIS49. A total of 10,036 structural/sequence variations (SVs) were identified when comparing with Chinese Long (CL), and known SVs controlling spines, tubercles, and carpel number were confirmed in XIS49 genome. Two QTLs of hypocotyl elongation under low light, SH3.1 and SH6.1, were fine-mapped using introgression lines (donor parent, XIS49; recurrent parent, CL). SH3.1 encodes a red-light receptor Phytochrome B (PhyB, CsaV3_3G015190). A ∼4 kb region with large deletion and highly divergent regions (HDRs) were identified in the promoter of the PhyB gene in XIS49. Loss of function of this PhyB caused a super-long hypocotyl phenotype. SH6.1 encodes a CCCH-type zinc finger protein FRIGIDA-ESSENTIAL LIKE (FEL, CsaV3_6G050300). FEL negatively regulated hypocotyl elongation but it was transcriptionally suppressed by long terminal repeats retrotransposon insertion in CL cucumber. Mechanistically, FEL physically binds to the promoter of CONSTITUTIVE PHOTOMORPHOGENIC 1a (COP1a), regulating the expression of COP1a and the downstream hypocotyl elongation. These above results demonstrate the genetic mechanism of cucumber hypocotyl elongation under low light.

Kinesin light chain 1 stabilizes insulin receptor substrate 1 to regulate the IGF-1-AKT signaling pathway during myoblast differentiation.

The IGF signaling pathway plays critical role in regulating skeletal myogenesis. We have demonstrated that KIF5B, the heavy chain of kinesin-1 motor, promotes myoblast differentiation through regulating IGF-p38MAPK activation. However, the roles of the kinesin light chain (Klc) in IGF pathway and myoblast differentiation remain elusive. In this study, we found that Klc1 was upregulated during muscle regeneration and downregulated in senescence mouse muscles and dystrophic muscles from mdx (X-linked muscular dystrophic) mice. Gain- and loss-of-function experiments further displayed that Klc1 promotes AKT-mTOR activity and positively regulates myogenic differentiation. We further identified that the expression levels of IRS1, the critical node of IGF-1 signaling, are downregulated in Klc1-depleted myoblasts. Coimmunoprecipitation study revealed that IRS1 interacted with the 88-154 amino acid sequence of Klc1 via its PTB domain. Notably, the reduced Klc1 levels were found in senescence and osteoporosis skeletal muscle samples from both mice and human. Taken together, our findings suggested a crucial role of Klc1 in the regulation of IGF-AKT pathway during myogenesis through stabilizing IRS1, which might ultimately influence the development of muscle-related disorders.

Time required for commitment to T cell proliferation depends on TCR affinity and cytokine response.

T cell activation and effector functions are determined by the affinity of the interaction between T cell receptor (TCR) and its antigenic peptide MHC (pMHC) ligand. A better understanding of the quantitative aspects of TCR-pMHC affinity-dependent T cell activation is critical for the development of new immunotherapeutic strategies. However, the role of TCR-pMHC affinity in regulating the kinetics of CD8+ T cell commitment to proliferation and differentiation is unknown. Here, we show that the stronger the TCR-pMHC affinity, the shorter the time of T cell-APC co-culture required to commit CD8+ T cells to proliferation. The time threshold for T cell cytokine production is much lower than that for cell proliferation. There is a strong correlation between affinity-dependent differences in AKT phosphorylation and T cell proliferation. The cytokine IL-15 increases the poor proliferation of T cells stimulated with low affinity pMHC, suggesting that pro-inflammatory cytokines can override the affinity-dependent features of T cell proliferation.

A Bioinspired Gradient Design Strategy for Cellulose-Based Electromagnetic Wave Absorbing Structural Materials.

Cellulose nanofiber (CNF) possesses excellent intrinsic properties, and many CNF-based high-performance structural and functional materials have been developed recently. However, the coordination of the mechanical properties and functionality is still a considerable challenge. Here, a CNF-based structural material is developed by a bioinspired gradient structure design using hollow magnetite nanoparticles and the phosphorylation-modified CNF as building blocks, which simultaneously achieves a superior mechanical performance and electromagnetic wave absorption (EMA) ability. Benefiting from the gradient design, the flexural strength of the structural material reached ∼205 MPa. Meanwhile, gradient design improves impedance matching, contributing to the high EMA ability (-59.5 dB) and wide effective absorption width (5.20 GHz). Besides, a low coefficient of thermal expansion and stable storage modulus was demonstrated as the temperature changes. The excellent mechanical, thermal, and EMA performance exhibited great potential for application in stealth equipment and electromagnetic interference protecting electronic packaging materials.