State-selective modulation of heterotrimeric Gαs signaling with macrocyclic peptides.

The G protein-coupled receptor cascade leading to production of the second messenger cAMP is replete with pharmacologically targetable proteins, with the exception of the Gα subunit, Gαs. GTPases remain largely undruggable given the difficulty of displacing high-affinity guanine nucleotides and the lack of other drug binding sites. We explored a chemical library of 1012 cyclic peptides to expand the chemical search for inhibitors of this enzyme class. We identified two macrocyclic peptides, GN13 and GD20, that antagonize the active and inactive states of Gαs, respectively. Both macrocyclic peptides fine-tune Gαs activity with high nucleotide-binding-state selectivity and G protein class-specificity. Co-crystal structures reveal that GN13 and GD20 distinguish the conformational differences within the switch II/α3 pocket. Cell-permeable analogs of GN13 and GD20 modulate Gαs/Gßγ signaling in cells through binding to crystallographically defined pockets. The discovery of cyclic peptide inhibitors targeting Gαs provides a path for further development of state-dependent GTPase inhibitors.

Cerebrospinal fluid immune dysregulation during healthy brain aging and cognitive impairment.

Cerebrospinal fluid (CSF) contains a tightly regulated immune system. However, knowledge is lacking about how CSF immunity is altered with aging or neurodegenerative disease. Here, we performed single-cell RNA sequencing on CSF from 45 cognitively normal subjects ranging from 54 to 82 years old. We uncovered an upregulation of lipid transport genes in monocytes with age. We then compared this cohort with 14 cognitively impaired subjects. In cognitively impaired subjects, downregulation of lipid transport genes in monocytes occurred concomitantly with altered cytokine signaling to CD8 T cells. Clonal CD8 T effector memory cells upregulated C-X-C motif chemokine receptor 6 (CXCR6) in cognitively impaired subjects. The CXCR6 ligand, C-X-C motif chemokine ligand 16 (CXCL16), was elevated in the CSF of cognitively impaired subjects, suggesting CXCL16-CXCR6 signaling as a mechanism for antigen-specific T cell entry into the brain. Cumulatively, these results reveal cerebrospinal fluid immune dysregulation during healthy brain aging and cognitive impairment.

Single-crystalline metal-oxide dielectrics for top-gate 2D transistors.

Two-dimensional (2D) structures composed of atomically thin materials with high carrier mobility have been studied as candidates for future transistors1-4. However, owing to the unavailability of suitable high-quality dielectrics, 2D field-effect transistors (FETs) cannot attain the full theoretical potential and advantages despite their superior physical and electrical properties3,5,6. Here we demonstrate the fabrication of atomically thin single-crystalline Al2O3 (c-Al2O3) as a high-quality top-gate dielectric in 2D FETs. By using intercalative oxidation techniques, a stable, stoichiometric and atomically thin c-Al2O3 layer with a thickness of 1.25 nm is formed on the single-crystalline Al surface at room temperature. Owing to the favourable crystalline structure and well-defined interfaces, the gate leakage current, interface state density and dielectric strength of c-Al2O3 meet the International Roadmap for Devices and Systems requirements3,5,7. Through a one-step transfer process consisting of the source, drain, dielectric materials and gate, we achieve top-gate MoS2 FETs characterized by a steep subthreshold swing of 61 mV dec-1, high on/off current ratio of 108 and very small hysteresis of 10 mV. This technique and material demonstrate the possibility of producing high-quality single-crystalline oxides suitable for integration into fully scalable advanced 2D FETs, including negative capacitance transistors and spin transistors.

Brain-restricted mTOR inhibition with binary pharmacology.

On-target-off-tissue drug engagement is an important source of adverse effects that constrains the therapeutic window of drug candidates1,2. In diseases of the central nervous system, drugs with brain-restricted pharmacology are highly desirable. Here we report a strategy to achieve inhibition of mammalian target of rapamycin (mTOR) while sparing mTOR activity elsewhere through the use of the brain-permeable mTOR inhibitor RapaLink-1 and the brain-impermeable FKBP12 ligand RapaBlock. We show that this drug combination mitigates the systemic effects of mTOR inhibitors but retains the efficacy of RapaLink-1 in glioblastoma xenografts. We further present a general method to design cell-permeable, FKBP12-dependent kinase inhibitors from known drug scaffolds. These inhibitors are sensitive to deactivation by RapaBlock, enabling the brain-restricted inhibition of their respective kinase targets.

An atlas of gene regulatory elements in adult mouse cerebrum.

The mammalian cerebrum performs high-level sensory perception, motor control and cognitive functions through highly specialized cortical and subcortical structures1. Recent surveys of mouse and human brains with single-cell transcriptomics2-6 and high-throughput imaging technologies7,8 have uncovered hundreds of neural cell types distributed in different brain regions, but the transcriptional regulatory programs that are responsible for the unique identity and function of each cell type remain unknown. Here we probe the accessible chromatin in more than 800,000 individual nuclei from 45 regions that span the adult mouse isocortex, olfactory bulb, hippocampus and cerebral nuclei, and use the resulting data to map the state of 491,818 candidate cis-regulatory DNA elements in 160 distinct cell types. We find high specificity of spatial distribution for not only excitatory neurons, but also most classes of inhibitory neurons and a subset of glial cell types. We characterize the gene regulatory sequences associated with the regional specificity within these cell types. We further link a considerable fraction of the cis-regulatory elements to putative target genes expressed in diverse cerebral cell types and predict transcriptional regulators that are involved in a broad spectrum of molecular and cellular pathways in different neuronal and glial cell populations. Our results provide a foundation for comprehensive analysis of gene regulatory programs of the mammalian brain and assist in the interpretation of noncoding risk variants associated with various neurological diseases and traits in humans.

Strain-release alkylation of Asp12 enables mutant selective targeting of K-Ras-G12D.

K-Ras is the most commonly mutated oncogene in human cancer. The recently approved non-small cell lung cancer drugs sotorasib and adagrasib covalently capture an acquired cysteine in K-Ras-G12C mutation and lock it in a signaling-incompetent state. However, covalent inhibition of G12D, the most frequent K-Ras mutation particularly prevalent in pancreatic ductal adenocarcinoma, has remained elusive due to the lack of aspartate-targeting chemistry. Here we present a set of malolactone-based electrophiles that exploit ring strain to crosslink K-Ras-G12D at the mutant aspartate to form stable covalent complexes. Structural insights from X-ray crystallography and exploitation of the stereoelectronic requirements for attack of the electrophile allowed development of a substituted malolactone that resisted attack by aqueous buffer but rapidly crosslinked with the aspartate-12 of K-Ras in both GDP and GTP state. The GTP-state targeting allowed effective suppression of downstream signaling, and selective inhibition of K-Ras-G12D-driven cancer cell proliferation in vitro and xenograft growth in mice.

A SARS-CoV-2 protein interaction map reveals targets for drug repurposing.

A newly described coronavirus named severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which is the causative agent of coronavirus disease 2019 (COVID-19), has infected over 2.3 million people, led to the death of more than 160,000 individuals and caused worldwide social and economic disruption1,2. There are no antiviral drugs with proven clinical efficacy for the treatment of COVID-19, nor are there any vaccines that prevent infection with SARS-CoV-2, and efforts to develop drugs and vaccines are hampered by the limited knowledge of the molecular details of how SARS-CoV-2 infects cells. Here we cloned, tagged and expressed 26 of the 29 SARS-CoV-2 proteins in human cells and identified the human proteins that physically associated with each of the SARS-CoV-2 proteins using affinity-purification mass spectrometry, identifying 332 high-confidence protein-protein interactions between SARS-CoV-2 and human proteins. Among these, we identify 66 druggable human proteins or host factors targeted by 69 compounds (of which, 29 drugs are approved by the US Food and Drug Administration, 12 are in clinical trials and 28 are preclinical compounds). We screened a subset of these in multiple viral assays and found two sets of pharmacological agents that displayed antiviral activity: inhibitors of mRNA translation and predicted regulators of the sigma-1 and sigma-2 receptors. Further studies of these host-factor-targeting agents, including their combination with drugs that directly target viral enzymes, could lead to a therapeutic regimen to treat COVID-19.

MULocDeep web service for protein localization prediction and visualization at subcellular and suborganellar levels.

Predicting protein localization and understanding its mechanisms are critical in biology and pathology. In this context, we propose a new web application of MULocDeep with improved performance, result interpretation, and visualization. By transferring the original model into species-specific models, MULocDeep achieved competitive prediction performance at the subcellular level against other state-of-the-art methods. It uniquely provides a comprehensive localization prediction at the suborganellar level. Besides prediction, our web service quantifies the contribution of single amino acids to localization for individual proteins; for a group of proteins, common motifs or potential targeting-related regions can be derived. Furthermore, the visualizations of targeting mechanism analyses can be downloaded for publication-ready figures. The MULocDeep web service is available at https://www.mu-loc.org/.

CKBA suppresses mast cell activation via ERK signaling pathway in murine atopic dermatitis.

Atopic dermatitis (AD) is a common inflammatory skin disorder. Mast cells play an important role in AD because they regulate allergic reactions and inflammatory responses. However, whether and how the modulation of mast cell activity affects AD has not been determined. In this study, we aimed to determine the effects and mechanisms of 3-O-cyclohexanecarbonyl-11-keto-ß-boswellic acid (CKBA). This natural compound derivative alleviates skin inflammation by inhibiting mast cell activation and maintaining skin barrier homeostasis in AD. CKBA markedly reduced serum IgE levels and alleviated skin inflammation in calcipotriol (MC903)-induced AD mouse model. CKBA also restrained mast cell degranulation both in vitro and in vivo. RNA-seq analysis revealed that CKBA downregulated the extracellular signal-regulated kinase (ERK) signaling in BM-derived mast cells activated by anti-2,4-dinitrophenol/2,4-dinitrophenol-human serum albumin. We proved that CKBA suppressed mast cell activation via ERK signaling using the ERK activator (t-butyl hydroquinone) and inhibitor (selumetinib; AZD6244) in AD. Thus, CKBA suppressed mast cell activation in AD via the ERK signaling pathway and could be a therapeutic candidate drug for AD.

Enhancing X-Ray Sensitization with Multifunctional Nanoparticles.

In the progression of X-ray-based radiotherapy for the treatment of cancer, the incorporation of nanoparticles (NPs) has a transformative impact. This study investigates the potential of NPs, particularly those comprised of high atomic number elements, as radiosensitizers. This aims to optimize localized radiation doses within tumors, thereby maximizing therapeutic efficacy while preserving surrounding tissues. The multifaceted applications of NPs in radiotherapy encompass collaborative interactions with chemotherapeutic, immunotherapeutic, and targeted pharmaceuticals, along with contributions to photodynamic/photothermal therapy, imaging enhancement, and the integration of artificial intelligence technology. Despite promising preclinical outcomes, the paper acknowledges challenges in the clinical translation of these findings. The conclusion maintains an optimistic stance, emphasizing ongoing trials and technological advancements that bolster personalized treatment approaches. The paper advocates for continuous research and clinical validation, envisioning the integration of NPs as a revolutionary paradigm in cancer therapy, ultimately enhancing patient outcomes.

Ge-polymer bridge waveguide for mode-locked laser pulse generation.

A Ge-polymer hybrid waveguide is sandwiched between an indium phosphide (InP) reflective gain chip and a fiber Bragg grating (FBG) to construct a laser system. The hybrid waveguide serves as a bridge between the gain chip and the fiber with tailored mode-field matching at both facets. The 50-nm amorphous Ge (α-Ge) layer shows a nonlinear absorption effect at 1550 nm. The hybrid waveguide is further verified by a femtosecond laser transmission experiment to show the pulse width compression effect. Such waveguide is then integrated inside the laser cavity as a passive saturable absorber to modulate the longitudinal modes for a pulsed output. This polymer-bridged mode-locked laser adopts an InP gain chip for compact assembly and also a FBG with a flexible length to adjust the pulse repetition rate. The mode-locked laser output around the designed 50 MHz repetition rate is demonstrated. The pulse width is measured as 147 ps, and the signal-to-noise ratio is larger than 50 dB. This work introduces a "ternary" mode-locked laser system, taking advantage of discrete photonic components bridged by a polymer-based waveguide. It also proves the feasibility of applying α-Ge films as practical and low-cost saturable absorbers in photonic devices.

The mode detangler.

Astrophotonics aims to transfer photonic technology to the development of compact astronomical instruments. However, light coupling from a multimode fiber, typically adopted in modern observatories, to a single-mode photonic device still poses a challenge. Though a photonic lantern can enable this transition in a low-loss way, it requires that the number of single-mode fibers (SMFs) at the output is the same as the number of guided modes in the multimode fiber, resulting in a cumbersome fan-out of many single-mode devices to be connected. Herein, we invent an active device in a waveguide form called "the mode detangler" (MD). We show that it can adaptively transform a complex light field from a multimode fiber to a single-mode-like spot. In this way, only one single-mode device is required at the end. The path leading to the idea and the theory behind the mode detangling effect is explained, followed by numerical simulations and experimental demonstrations using a few-mode fiber as proof of concept. We believe this device has the potential to address the multimode-to-single-mode conversion challenge in astrophotonics but also sheds light on (de)multiplexing applications regarding spatial mode technology in optical communications.

EO nonlinear function generator.

An electro-optical programmable nonlinear function generator (PNFG) is developed on a multimode waveguide with four parallel thermal electrodes. The current on one electrode is chosen as the input, while the rest serve as function-defining units to modulate the multimode interference. The electro-thermo-optical effects are analyzed step by step and the impact on the eigenmode properties is derived. It shows that the optical output power variation by altered interference, in response to the input current, manifests as a complex ensemble of functions in general. The PNFG aims to find the special setting under which such relation can be simplified into some basic functions. Through an optimization program, a variety of such functions are found, including Sigmoid, SiLU, and Gaussian. Furthermore, the shape of these functions can be adjusted by finetuning the defining units. This device may be integrated in a large-scale photonic computing network that can tackle complex problems with nonlinear function adaptability.

Chemical acylation of an acquired serine suppresses oncogenic signaling of K-Ras(G12S).

Drugs that directly impede the function of driver oncogenes offer exceptional efficacy and a therapeutic window. The recently approved mutant selective small-molecule cysteine-reactive covalent inhibitor of the G12C mutant of K-Ras, sotorasib, provides a case in point. KRAS is the most frequently mutated proto-oncogene in human cancer, yet despite success targeting the G12C allele, targeted therapy for other hotspot mutants of KRAS has not been described. Here we report the discovery of small molecules that covalently target a G12S somatic mutation in K-Ras and suppress its oncogenic signaling. We show that these molecules are active in cells expressing K-Ras(G12S) but spare the wild-type protein. Our results provide a path to targeting a second somatic mutation in the oncogene KRAS by overcoming the weak nucleophilicity of an acquired serine residue. The chemistry we describe may serve as a basis for the selective targeting of other unactivated serines.

KRAS is vulnerable to reversible switch-II pocket engagement in cells.

Current small-molecule inhibitors of KRAS(G12C) bind irreversibly in the switch-II pocket (SII-P), exploiting the strong nucleophilicity of the acquired cysteine as well as the preponderance of the GDP-bound form of this mutant. Nevertheless, many oncogenic KRAS mutants lack these two features, and it remains unknown whether targeting the SII-P is a practical therapeutic approach for KRAS mutants beyond G12C. Here we use NMR spectroscopy and a cellular KRAS engagement assay to address this question by examining a collection of SII-P ligands from the literature and from our own laboratory. We show that the SII-Ps of many KRAS hotspot (G12, G13, Q61) mutants are accessible using noncovalent ligands, and that this accessibility is not necessarily coupled to the GDP state of KRAS. The results we describe here emphasize the SII-P as a privileged drug-binding site on KRAS and unveil new therapeutic opportunities in RAS-driven cancer.

One-Step Spraying Strategy for Fabricating Bioinspired, Graphene-Based, and Multifunctional-Integrated Coatings on Structural Steel with Good Water Repellency, Fireproofing, Anticorrosion, and Durability.

Traditionally, many coatings were merely concentrated on settling the inherent fire protection problem of steel structures, while surface contamination and corrosion susceptibility should also be considered. Concurrently addressing these problems in fireproof efficiency and surface multifunctionality has become an issue of great significance in further expanding the application value in industrial and daily scenarios. Based on this condition, ecofriendly, graphene-based, and superhydrophobic coatings with multifunctional integration were constructed on steel via a one-step spraying method. The as-prepared coatings mainly consist of epoxy resin (EP), silicone resin (SR), a cyclodextrin-based flame retardant (MCDPM), expandable graphite (EG), and multilayered graphene (MG). The results demonstrate that the water contact angle (WCA) and water sliding angle (WSA) of as-prepared coatings can reach 156.8 ± 1.6 and 5.8 ± 0.7°, respectively, revealing good water repellency and self-cleaning properties. The coatings can also exhibit adequate adaptability for various substrates including wood, polyurethane foam, and cotton fabrics. Besides, good durability and robustness of coatings have been also verified via acid/alkali immersion, outdoor exposure, O2/plasma etching, and linear abrasion tests. Simultaneously, the coatings can exhibit excellent anticorrosion capacity for steel materials via a double barrier effect. Most importantly, the coatings have exhibited the lowest backside temperature (234.5 °C) during fire impact tests, suggesting excellent fireproof and heat insulation performance. This fact can be ascribed to the conjunct action between the physical/chemical charring process of flame retardants and the remarkable thermal stability of graphene. Consequently, this article can be expected to further promote the development and application of multifunctional-integrated coatings for steel structures in more fields.

Mid1 promotes synovitis in rheumatoid arthritis via ubiquitin-dependent post-translational modification.

INTRODUCTION: Current anti-rheumatic drugs are primarily modulating immune cell activation, yet their effectiveness remained suboptimal. Therefore, novel therapeutics targeting alternative mechanisms, such as synovial activation, is urgently needed. OBJECTIVES: To explore the role of Midline-1 (Mid1) in synovial activation. METHODS: NOD.Cg-Prkdcscid Il2rgtm1Wjl/SzJ (NSG) mice were used to establish a subcutaneous xenograft model. Wild-type C57BL/6, Mid1-/-, Dpp4-/-, and Mid1-/-Dpp4-/- mice were used to establish a collagen-induced arthritis model. Cell viability, cell cycle, qPCR and western blotting analysis were used to detect MH7A proliferation, dipeptidyl peptidase-4 (DPP4) and Mid1 levels. Co-immunoprecipitation and proteomic analysis identified the candidate protein of Mid1 substrates. Ubiquitination assays were used to determine DPP4 ubiquitination status. RESULTS: An increase in Mid1, an E3 ubiquitin ligase, was observed in human RA synovial tissue by GEO dataset analysis, and this elevation was confirmed in a collagen-induced mouse arthritis model. Notably, deletion of Mid1 in a collagen-induced arthritis model completely protected mice from developing arthritis. Subsequent overexpression and knockdown experiments on MH7A, a human synoviocyte cell line, unveiled a previously unrecognized role of Mid1 in synoviocyte proliferation and migration, the key aspects of synovial activation. Co-immunoprecipitation and proteomic analysis identified DPP4 as the most significant candidate of Mid1 substrates. Mechanistically, Mid1 promoted synoviocyte proliferation and migration by inducing ubiquitin-mediated proteasomal degradation of DPP4. DPP4 deficiency led to increased proliferation, migration, and inflammatory cytokine production in MH7A, while reconstitution of DPP4 significantly abolished Mid1-induced augmentation of cell proliferation and activation. Additionally, double knockout model showed that DPP4 deficiency abolished the protective effect of Mid1 defect on arthritis. CONCLUSION: Overall, our findings suggest that the ubiquitination of DPP4 by Mid1 promotes synovial cell proliferation and invasion, exacerbating synovitis in RA. These results reveal a novel mechanism that controls synovial activation, positioning Mid1 as a promising target for therapeutic intervention in RA.

Pd Nanoparticle-Modified BiOBr/CdS S-Scheme Photocatalyst for Enhanced Conversion of CO2.

S-scheme heterojunction photocatalyst-coupled plasma-resonance effect can enhance the response range and absorption of light and charge transfer, and, at the same time, obtain strong redox ability, which is an effective way to improve CO2 conversion. In this work, plasma S-scheme heterojunctions of Pd/BiOBr/CdS with heterogeneous interfaces have been successfully constructed by a simple hydrothermal method. The possible reaction mechanism was proposed by in situ infrared, ultraviolet-visible spectroscopy (UV-vis), electron paramagnetic resonance (ESR), density functional theory (DFT), and electrochemical techniques. It was proved that the plasma S-scheme heterojunction can enhance the charge separation efficiency and improve the photocatalytic activity. When the loading ratio is Pd0.6-10%-BiOBr/CdS, it has the best performance, and the CO yield is 30.24 µmol/g, which is 15 and 30 times that of pure BiOBr and CdS, respectively. The results show that with the strong absorption of photon energy and the special electron transfer mode of S-scheme heterojunction, the charge can be effectively separated and transferred, and the photocatalytic activity is significantly improved. This study provides a useful strategy for charge transfer kinetics of plasma S-scheme heterojunction photocatalysts.

The phytoplankton community affects the energy metabolism and immunomodulation strategy of oyster during breeding seasons.

The mass mortality of Pacific oyster Crassostrea gigas has become a severe ecological and economic concern to Chinese aquaculture, which is proposed to be linked to the phytoplankton community in the farming waters. In the present study, both field and laboratory experiments were conducted to identify the phytoplankton taxa associated with oyster mortality and explore the molecular mechanism by which they affect the physiological health of oysters. The field experiment showed that more serious mortality of oysters was observed in the North Yellow Sea from July to September in 2018 (average survival rate of 75.11 %) than in 2019 (average survival rate of 85.78 %), with the proportion of Bacillariophyta (diatoms) in the phytoplankton community in 2018 lower than that in 2019. In comparison to 2019, reduced dry weight, lower glycogen and triglyceride contents in hepatopancreas, lower 17ß-estradiol and testosterone concentrations in gonad, as well as a generally weaker immune response against Vibrio splendidus stimulation were detected in the oysters sampled in 2018. The treatment of oysters with either starvation (starvation group) or Nitzschia closterium f. minutissima feeding (N. closterium group) was conducted to verify the field findings, with individuals reared in natural seawater as control. After 40 days of N. closterium feeding, dry weight, glycogen and triglyceride contents in hepatopancreas significantly increased, as well as the biosynthesis of sex hormones and gonadal maturation were promoted compared to the control and starvation groups. Moreover, a much stronger immune response against V. splendidus stimulation was observed in the oysters of N. closterium group, with the fold-changes of norepinephrine content in serum, SOD activity in hepatopancreas, and the mRNA expression level of IL17-5 and HSP70 in haemocytes higher than those in the control and starvation groups. Collectively, these results suggested that lack of diatoms in the farming waters suppressed the energy storage and gonadal maturation of adult oysters, and also resulted in a compromised immune response against bacterial infection, which may be a leading cause of the mass mortality of oysters living in diatom-deficient waters during breeding seasons.