Time-resolved protein activation by proximal decaging in living systems.

A universal gain-of-function approach for selective and temporal control of protein activity in living systems is crucial to understanding dynamic cellular processes. Here we report development of a computationally aided and genetically encoded proximal decaging (hereafter, CAGE-prox) strategy that enables time-resolved activation of a broad range of proteins in living cells and mice. Temporal blockage of protein activity was computationally designed and realized by genetic incorporation of a photo-caged amino acid in proximity to the functional site of the protein, which can be rapidly removed upon decaging, resulting in protein re-activation. We demonstrate the wide applicability of our method on diverse protein families, which enabled orthogonal tuning of cell signalling and immune responses, temporal profiling of proteolytic substrates upon caspase activation as well as the development of protein-based pro-drug therapy. We envision that CAGE-prox will open opportunities for the gain-of-function study of proteins and dynamic biological processes with high precision and temporal resolution.

Encouraging the resumption of economic activity after COVID-19: Evidence from a large scale-field experiment in China.

As the COVID-19 pandemic comes to an end, governments find themselves facing a new challenge: motivating citizens to resume economic activity. What is an effective way to do so? We investigate this question using a field experiment in the city of Zhengzhou, China, immediately following the end of the city's COVID-19 lockdown. We assessed the effect of a descriptive norms intervention providing information about the proportion of participants' neighbors who have resumed economic activity. We find that informing individuals about their neighbors' plans to visit restaurants increases the fraction of participants visiting restaurants by 12 percentage points (37%), among those participants who underestimated the proportion of neighbors who resumed economic activity. Those who overestimated did not respond by reducing restaurant attendance (the intervention yielded no "boomerang" effect); thus, our descriptive norms intervention yielded a net positive effect. We explore the moderating role of risk preferences and the effect of the intervention on subjects' perceived risk of going to restaurants, as well as the contrast with an intervention for parks, which were already perceived as safe. All of these analyses suggest our intervention worked by reducing the perceived risk of going to restaurants.

Lutetium Texaphyrin-Celecoxib Conjugate as a Potential Immuno-Photodynamic Therapy Agent.

Immuno-photodynamic therapy (IPDT) has emerged as a new modality for cancer treatment. Novel photosensitizers can help achieve the promise inherent in IPDT, namely, the complete eradication of a tumor without recurrence. We report here a small molecule photosensitizer conjugate, LuCXB. This IPDT agent integrates a celecoxib (cyclooxygenase-2 inhibitor) moiety with a near-infrared absorbing lutetium texaphyrin photocatalytic core. In aqueous environments, the two components of LuCXB are self-associated through inferred donor-acceptor interactions. A consequence of this intramolecular association is that upon photoirradiation with 730 nm light, LuCXB produces superoxide radicals (O2-•) via a type I photodynamic pathway; this provides a first line of defense against the tumor while promoting IPDT. For in vivo therapeutic applications, we prepared a CD133-targeting, aptamer-functionalized exosome-based nanophotosensitizer (Ex-apt@LuCXB) designed to target cancer stem cells. Ex-apt@LuCXB was found to display good photosensitivity, acceptable biocompatibility, and robust tumor targetability. Under conditions of photoirradiation, Ex-apt@LuCXB acts to amplify IPDT while exerting a significant antitumor effect in both liver and breast cancer mouse models. The observed therapeutic effects are attributed to a synergistic mechanism that combines antiangiogenesis and photoinduced cancer immunotherapy.

Effective treatment of corticosteroid-induced facial erythema using fractional radiofrequency microneedling.

OBJECTIVES: To investigate the efficacy of Fractional Radiofrequency Microneedling (FRM) in treating corticosteroid-induced facial erythema. METHODS: A retrospective study was conducted involving eight patients diagnosed as corticosteroid-induced facial erythema. Each patient underwent a single session of FRM. Evaluative measures included Clinician's Erythema Assessment (CEA), Patient's Self-Assessment (PSA), assessment of telangiectasia severity, procedure-associated pain (10-point scale), patient satisfaction (3-point scale) and secondary outcomes. RESULTS: The study found a 75% success rate and 100% effectiveness rate in alleviating erythema symptoms. CEA and PSA scores decreased by 67.7% and 78.1%, respectively. No cases of erythema rebound were recorded during the 3-month follow-up period. CONCLUSIONS: FRM demonstrated effectiveness and safety in treating facial erythema, offering promising advancement in dermatologic therapeutics.

Positive effects of napping on memory consolidation and resistance against interference.

PURPOSE: This study explored the relationship between naps and memory among habitual nappers in China. METHODS: Medical college students participated and were divided into 30-min, 60-min, and 90-min time-in-bed groups. To evaluate declarative and procedural memory performance, A-B and A-C interfering word pair and interfering finger tapping tasks were employed. RESULTS: Among 60 students, a significant decrease in the correct recall rate in the declarative task after having a nap was found only in the 30-min group (p = 0.005). After learning interference (A-C word pairs), the correct recall rate for the declarative task decreased significantly in all interference tests (ps < 0.001). In the procedural task, the speed of sequence A in the retests increased after having a nap in all three groups (ps < 0.048), with a significant decrease in accuracy only in the 30-min group (p = 0.042). After learning interference (sequence B) in the procedural task, the speed of sequence A increased in the 60-min group after 1 h (p = 0.049), and both the 60-min and 90-min groups showed increased speed after one night (ps < 0.022). No significant improvement in speed was found in the 30-min group (ps > 0.05), and this group showed the lowest accuracy for sequence A (ps < 0.16). CONCLUSION: A habitual nap time-in-bed of 60 or 90 min had better effects on declarative and procedural memory consolidation and better memory resistance against interference in procedural memory.

Integration of protein context improves protein-based COVID-19 patient stratification.

BACKGROUND: Classification of disease severity is crucial for the management of COVID-19. Several studies have shown that individual proteins can be used to classify the severity of COVID-19. Here, we aimed to investigate whether integrating four types of protein context data, namely, protein complexes, stoichiometric ratios, pathways and network degrees will improve the severity classification of COVID-19. METHODS: We performed machine learning based on three previously published datasets. The first was a SWATH (sequential window acquisition of all theoretical fragment ion spectra) MS (mass spectrometry) based proteomic dataset. The second was a TMTpro 16plex labeled shotgun proteomics dataset. The third was a SWATH dataset of an independent patient cohort. RESULTS: Besides twelve proteins, machine learning also prioritized two complexes, one stoichiometric ratio, five pathways, and five network degrees, resulting a 25-feature panel. As a result, a model based on the 25 features led to effective classification of severe cases with an AUC of 0.965, outperforming the models with proteins only. Complement component C9, transthyretin (TTR) and TTR-RBP (transthyretin-retinol binding protein) complex, the stoichiometric ratio of SAA2 (serum amyloid A proteins 2)/YLPM1 (YLP Motif Containing 1), and the network degree of SIRT7 (Sirtuin 7) and A2M (alpha-2-macroglobulin) were highlighted as potential markers by this classifier. This classifier was further validated with a TMT-based proteomic data set from the same cohort (test dataset 1) and an independent SWATH-based proteomic data set from Germany (test dataset 2), reaching an AUC of 0.900 and 0.908, respectively. Machine learning models integrating protein context information achieved higher AUCs than models with only one feature type. CONCLUSION: Our results show that the integration of protein context including protein complexes, stoichiometric ratios, pathways, network degrees, and proteins improves phenotype prediction.

Beam manipulation for quantum dot light-emitting diode with an Ag grating and a phase-gradient metasurface.

The quantum dot (QD) light-emitting diode (LED) is a robust scheme for single photon source. However, the spontaneous emission of a QD LED has arbitrary directions and polarizations, which is disadvantage for photon collection and manipulation. We propose a QD LED integrated with an Ag grating and a phase-gradient metasurface. The circular patterned Ag grating is adopted to collimate the emission beam with right phase and improve its spatial coherence, therefore a phase-gradient metasurface can work for beam manipulation. The 10°, 20°, and 30° angle deflection as well as doughnut-pattern generation are demonstrated by numerical simulation. A small metasurface with the width of 6 µm can provide a collection efficiency of 25.9% at the deflection angle of 10°. Furthermore, only one single QD can be selected from a QD assembly with a low-density.

Predictive Values of sTREM-1, PCT and CRP for Multiple Trauma-Induced Acute Respiratory Distress Syndrome Complicated with Pulmonary Infection.

BACKGROUND: The aim is to investigate the predictive values of soluble triggering receptor expressed on myeloid cells-1 (sTREM-1), procalcitonin (PCT) and C-reactive protein (CRP) for multiple trauma-induced acute respiratory distress syndrome (ARDS) complicated with pulmonary infection. METHODS: One hundred and twelve patients with multiple trauma-induced ARDS admitted from April 2019 to April 2021 were selected and divided into infection group (n = 49) and non-infection group (n = 63). Their general data and laboratory test indicators were compared. Multivariate logistic regression analysis was utilized to identify the influencing factors for concurrent pulmonary infection. Pearson's analysis was employed to analyze the correlations of sTREM-1, PCT, and CRP with other influencing factors. The predictive values of sTREM-1, PCT, and CRP for pulmonary infection in ARDS patients were evaluated using receiver operating characteristic (ROC) curves. Based on the cutoff values, the patients were assigned to low-, medium-, and high-risk groups. Survival curves were plotted by Kaplan-Meier method to compare the 28-day survival. RESULTS: The infection group had significantly higher injury severity score (ISS), Acute Physiology and Chronic Health Evaluation II (APACHE II) score, sTREM-1, PCT, CRP, and macrophage inflammatory protein (MIP)-1α, longer tracheal intubation time and intensive care unit (ICU) stay time, and lower oxygenation index than those of the non-infection group (p < 0.05). Multivariate logistic regression analysis revealed that increased ISS, APACHE II score, as well as elevated blood concentrations of sTREM-1, PCT, CRP and MIP-1α were risk factors for concurrent pulmonary infection (p < 0.05). sTREM-1, PCT, and CRP were positively correlated with ISS, APACHE II score, and MIP-1α (p < 0.05). The areas under ROC curves of sTREM-1, PCT, CRP, and their combination were 0.795, 0.784, 0.756, and 0.860, respectively (p < 0.001), indicating high predictive values. The survival rate of the high-risk group (46.43%) was significantly lower than those of the low-risk group (89.58%) and medium-risk group (75.00%) (p < 0.05). CONCLUSIONS: sTREM-1, PCT, and CRP are highly expressed in serum of patients with multiple trauma-induced ARDS complicated with pulmonary infection. The combined detection of three markers is of high predictive value.

Metabolic Engineering of the Isopentenol Utilization Pathway Enhanced the Production of Terpenoids in Chlamydomonas reinhardtii.

Eukaryotic green microalgae show considerable promise for the sustainable light-driven biosynthesis of high-value fine chemicals, especially terpenoids because of their fast and inexpensive phototrophic growth. Here, the novel isopentenol utilization pathway (IUP) was introduced into Chlamydomonas reinhardtii to enhance the hemiterpene (isopentenyl pyrophosphate, IPP) titers. Then, diphosphate isomerase (IDI) and limonene synthase (MsLS) were further inserted for limonene production. Transgenic algae showed 8.6-fold increase in IPP compared with the wild type, and 23-fold increase in limonene production compared with a single MsLS expressing strain. Following the culture optimization, the highest limonene production reached 117 µg/L, when the strain was cultured in a opt2 medium supplemented with 10 mM isoprenol under a light: dark regimen. This demonstrates that transgenic algae expressing the IUP represent an ideal chassis for the high-value terpenoid production. The IUP will facilitate further the metabolic and enzyme engineering to enhance the terpenoid titers by significantly reducing the number of enzyme steps required for an optimal biosynthesis.

Predicting neighborhoods' socioeconomic attributes using restaurant data.

Accessing high-resolution, timely socioeconomic data such as data on population, employment, and enterprise activity at the neighborhood level is critical for social scientists and policy makers to design and implement location-based policies. However, in many developing countries or cities, reliable local-scale socioeconomic data remain scarce. Here, we show an easily accessible and timely updated location attribute-restaurant-can be used to accurately predict a range of socioeconomic attributes of urban neighborhoods. We merge restaurant data from an online platform with 3 microdatasets for 9 Chinese cities. Using features extracted from restaurants, we train machine-learning models to estimate daytime and nighttime population, number of firms, and consumption level at various spatial resolutions. The trained model can explain 90 to 95% of the variation of those attributes across neighborhoods in the test dataset. We analyze the tradeoff between accuracy, spatial resolution, and number of training samples, as well as the heterogeneity of the predicted results across different spatial locations, demographics, and firm industries. Finally, we demonstrate the cross-city generality of this method by training the model in one city and then applying it directly to other cities. The transferability of this restaurant model can help bridge data gaps between cities, allowing all cities to enjoy big data and algorithm dividends.

Clean air as an experience good in urban China.

The surprise economic shutdown due to COVID-19 caused a sharp improvement in urban air quality in many previously heavily polluted Chinese cities. If clean air is a valued experience good, then this short-term reduction in pollution in spring 2020 could have persistent medium-term effects on reducing urban pollution levels as cities adopt new "blue sky" regulations to maintain recent pollution progress. We document that China's cross-city Environmental Kuznets Curve shifts as a function of a city's demand for clean air. We rank 144 cities in China based on their population's baseline sensitivity to air pollution and with respect to their recent air pollution gains due to the COVID shutdown. The largest experience good effect should take place for cities featuring a high pollution sensitive population and where air quality has sharply improved during the pandemic. The residents of these cities have increased their online discussions focused on environmental protection, and local officials are incorporating "green" industrial subsidies into post-COVID stimulus policies.

Air mediates the impact of a compliant hemisphere on a rigid smooth surface.

Fleeting contact between solids immersed in a fluid medium governs the response of critically important materials, from coffee to soil. Rapid impact of soft solids occurs in systems as diverse as car tires, soft robotic locomotion and suspensions, including soil and coffee. In each of these systems, the dynamics are fundamentally altered by the presence of a fluid layer mediating solid contact. However, observing this class of interactions directly is challenging, as the relevant time and length scales are extremely small. Here we directly image the interface between a soft elastic hemisphere and a flat rigid substrate during rapid impact over a wide range of impact velocities V at high temporal and spatial resolution using the Virtual Frame Technique (VFT). In each experiment, a pocket of air is trapped in a dimple between the impactor and the substrate, preventing direct solid-solid contact at the apex of the hemisphere. Thus, unlike the quasi-static Hertzian solution where contact forms in an ellipse, in each rapid air-mediated impact, contact forms in an annular region which rapidly grows both inward toward the impact axis, and rapidly outward away from the impact axis. We find that the radius of initial contact varies non-monotonically with V, indicating a transition between elastically dominated dynamics to inertially dominated dynamics. Furthermore, we find that for slower impact speeds, where the outer contact front cannot outpace the Rayleigh velocity, contact expands in a patchy manner, indicating an elasto-lubricative instability. These behaviors, observed using the VFT, occur in regimes relevant to a wide variety of soft systems, and might modulate frictional properties during contact. The size of the air pocket varies with V and impactor stiffness. Our measurements reveal an unanticipated, sudden transition of the air pocket's size as V increases beyond 1 m s-1 and multiple modes of air entrainment at the advancing solid-solid contact front that depend on the front's velocity.

Household income inequality aggravates high-temperature exposure inequality in urban China.

The exposure to extremely high temperatures varies across population groups. Those with better adaptation strategies (such as air conditioning) suffer less. This paper combines China's daily mean temperature data with comprehensive national survey data at the household level and estimates the relationship between high-temperature exposure and adaptation behavior of urban dwellers. We find that the usage of air conditioning and electric fans by urban households in China increases with their summer high-temperature exposures. The rise in the number of days with extreme heat (mean temperature exceeding 80 °F) induces the purchase and use of air conditioning. High-temperature adaptability varied across households-the rich are more likely to increase air conditioning usage to cope with the high-temperature discomfort; while the poor are less likely to afford such a market product for adaptation, they suffer more from high-temperature exposure. Such a variation in the affordability and usage of market products to adapt to climate risks will exacerbate the climate-induced inequality.

MicroRNA-644a promotes apoptosis of hepatocellular carcinoma cells by downregulating the expression of heat shock factor 1.

In this study, we investigated the role of microRNA-644a (miR-644a) in the growth and survival of hepatocellular carcinoma (HCC) cells. MiR-644a levels were lower in HCC tissues than in adjacent peri-cancerous tissues (n = 135). MiR-644a expression was inversely correlated with heat shock factor 1 (HSF1) expression, tumour diameter and TNM stage. Moreover, HepG2 and SMMC-7721 cell lines showed lower miR-644a expression than normal L-O2 hepatocytes. MiR-644a overexpression in HepG2 and SMMC-7721 cells increased apoptosis by downregulating HSF1. Dual luciferase reporter assays confirmed the presence of a miR-644a binding site in the 3'-untranslated region (3'-UTR) of HSF1. Xenograft tumours derived from SMMC-7721 cells transfected with a miR-664a mimic showed less growth than tumours derived from untransfected controls. Protein chip analysis revealed that miR-644a-overexpressing SMMC-7721 and HepG2 cells strongly expressed pro-apoptotic BH3-only proteins, such as BID, BAD, BIM, SMAC, Apaf-1 and cleaved caspases-3 and -9. These findings suggest miR-644a promotes apoptosis in HCC cells by inhibiting HSF1.

Dissection of Kinase Isoforms through Orthogonal and Chemical Inducible Signaling Cascades.

Interference from endogenous signaling enzymes represents a major hurdle for building orthogonal signaling cascades inside cells, particularly among closely related isoforms within an enzyme family. Here, we employed a genetically encoded chemical decaging strategy to build orthogonally activated kinase isoforms, with the endogenous counterparts temporally disabled by an extracellularly delivered bacterial effector. This approach eliminated any potential interference from other kinase isoforms as well as endogenous kinases, which allowed the specific, gain-of-function report of mitogen-activated protein kinase kinase 1 (MEK1) activity as opposed to MEK2 with high temporal resolution. Our study dissected the distinct enzymatic activity, feedback regulation and signal outputs between these closely related kinase isoforms.

Palladium-Triggered Chemical Rescue of Intracellular Proteins via Genetically Encoded Allene-Caged Tyrosine.

Chemical de-caging has emerged as an attractive strategy for gain-of-function study of proteins via small-molecule reagents. The previously reported chemical de-caging reactions have been largely centered on liberating the side chain of lysine on a given protein. Herein, we developed an allene-based caging moiety and the corresponding palladium de-caging reagents for chemical rescue of tyrosine (Tyr) activity on intracellular proteins. This bioorthogonal de-caging pair has been successfully applied to unmask enzymatic Tyr sites (e.g., Y671 on Taq polymerase and Y728 on Anthrax lethal factor) as well as the post-translational Tyr modification site (Y416 on Src kinase) in vitro and in living cells. Our strategy provides a general platform for chemical rescue of Tyr-dependent protein activity inside cells.

China's bullet trains facilitate market integration and mitigate the cost of megacity growth.

Megacity growth in the developing world is fueled by a desire to access their large local labor markets. Growing megacities suffer from high levels of traffic congestion and pollution, which degrade local quality of life. Transportation technology that allows individuals to access the megacity without living within its boundaries offers potentially large social benefits, because individuals can enjoy the benefits of urban agglomeration while not paying megacity real estate rents and suffering from the city's social costs. This paper presents evidence supporting the claim that China's bullet trains are playing this role. The bullet train is regarded as one of the most significant technological breakthroughs in passenger transportation developed in the second half of the 20th century. Starting in 2007, China has introduced several new bullet trains that connect megacities such as Beijing, Shanghai, and Guangzhou with nearby cities. Through facilitating market integration, bullet trains will stimulate the development of second- and third-tier cities. By offering households and firms a larger menu of location alternatives, bullet trains help to protect the quality of life of the growing urban population. We document that this transport innovation is associated with rising real estate prices in the nearby secondary cities.

Illuminating biological processes through site-specific protein labeling.

Coupling genetically encoded peptide tags or unnatural amino acids (UAAs) with bioorthogonal reactions allows for precise control over the protein-labeling sites as well as the wide choice of labeling dyes. However, the value of these site-specific protein labeling strategies in a real biology setting, particularly their advantages over conventional labeling methods including fluorescent proteins (FPs), remains to be fully demonstrated. In this tutorial review, we first introduce various strategies for site-specific protein labeling that utilize artificial peptide sequences or genetically encoded UAAs as the labeling handle. Emphasis will be placed on introducing the advantages of protein site-specific labeling techniques as well as their applications in solving biological problems, particularly as to why a site-specific protein labeling approach is needed. Finally, beyond the widely used single site-specific labeling methods, the recently emerged dual site-specific protein labeling strategies will be introduced together with their fast-growing potential in illustrating biological processes.

Optimized Tetrazine Derivatives for Rapid Bioorthogonal Decaging in Living Cells.

The inverse-electron-demand Diels-Alder (iDA) reaction has recently been repurposed as a bioorthogonal decaging reaction by accelerating the elimination process after an initial cycloaddition between trans-cyclooctene (TCO) and tetrazine (TZ). Herein, we systematically surveyed 3,6-substituted TZ derivatives by using a fluorogenic TCO-coumarin reporter followed by LC-MS analysis, which revealed that the initial iDA cycloaddition step was greatly accelerated by electron-withdrawing groups (EWGs) while the subsequent elimination step was strongly suppressed by EWGs. In addition, smaller substituents facilitated the decaging process. These findings promoted us to design and test unsymmetric TZs bearing an EWG group and a small non-EWG group at the 3- and 6-position, respectively. These TZs showed remarkably enhanced decaging rates, enabling rapid iDA-mediated protein activation in living cells.