Mechanisms and inhibition of Porcupine-mediated Wnt acylation.

Wnt signalling is essential for regulation of embryonic development and adult tissue homeostasis1-3, and aberrant Wnt signalling is frequently associated with cancers4. Wnt signalling requires palmitoleoylation on a hairpin 2 motif by the endoplasmic reticulum-resident membrane-bound O-acyltransferase Porcupine5-7 (PORCN). This modification is indispensable for Wnt binding to its receptor Frizzled, which triggers signalling8,9. Here we report four cryo-electron microscopy structures of human PORCN: the complex with the palmitoleoyl-coenzyme A (palmitoleoyl-CoA) substrate; the complex with the PORCN inhibitor LGK974, an anti-cancer drug currently in clinical trials10; the complex with LGK974 and WNT3A hairpin 2 (WNT3Ap); and the complex with a synthetic palmitoleoylated WNT3Ap analogue. The structures reveal that hairpin 2 of WNT3A, which is well conserved in all Wnt ligands, inserts into PORCN from the lumenal side, and the palmitoleoyl-CoA accesses the enzyme from the cytosolic side. The catalytic histidine triggers the transfer of the unsaturated palmitoleoyl group to the target serine on the Wnt hairpin 2, facilitated by the proximity of the two substrates. The inhibitor-bound structure shows that LGK974 occupies the palmitoleoyl-CoA binding site to prevent the reaction. Thus, this work provides a mechanism for Wnt acylation and advances the development of PORCN inhibitors for cancer treatment.

ppGpp Coordinates Nucleotide and Amino-Acid Synthesis in E. coli During Starvation.

(p)ppGpp is a nucleotide messenger universally produced in bacteria following nutrient starvation. In E. coli, ppGpp inhibits purine nucleotide synthesis by targeting several different enzymes, but the physiological significance of their inhibition is unknown. Here, we report the structural basis of inhibition for one target, Gsk, the inosine-guanosine kinase. Gsk creates an unprecedented, allosteric binding pocket for ppGpp by restructuring terminal sequences, which restrains conformational dynamics necessary for catalysis. Guided by this structure, we generated a chromosomal mutation that abolishes Gsk regulation by ppGpp. This mutant strain accumulates abnormally high levels of purine nucleotides following amino-acid starvation, compromising cellular fitness. We demonstrate that this unrestricted increase in purine nucleotides is detrimental because it severely depletes pRpp and essential, pRpp-derived metabolites, including UTP, histidine, and tryptophan. Thus, our results reveal the significance of ppGpp's regulation of purine nucleotide synthesis and a critical mechanism by which E. coli coordinates biosynthetic processes during starvation.

Identification of a broadly conserved family of enzymes that hydrolyze (p)ppApp.

Bacteria produce a variety of nucleotide second messengers to adapt to their surroundings. Although chemically similar, the nucleotides guanosine penta- and tetraphosphate [(p)ppGpp] and adenosine penta- and tetraphosphate [(p)ppApp] have distinct functions in bacteria. (p)ppGpp mediates survival under nutrient-limiting conditions and its intracellular levels are regulated by synthetases and hydrolases belonging to the RelA-SpoT homolog (RSH) family of enzymes. By contrast, (p)ppApp is not known to be involved in nutrient stress responses and is synthesized by RSH-resembling toxins that inhibit the growth of bacterial cells. However, it remains unclear whether there exists a family of hydrolases that specifically act on (p)ppApp to reverse its toxic effects. Here, we present the structure and biochemical characterization of adenosine 3'-pyrophosphohydrolase 1 (Aph1), the founding member of a monofunctional (p)ppApp hydrolase family of enzymes. Our work reveals that Aph1 adopts a histidine-aspartate (HD)-domain fold characteristic of phosphohydrolase metalloenzymes and its activity mitigates the growth inhibitory effects of (p)ppApp-synthesizing toxins. Using an informatic approach, we identify over 2,000 putative (p)ppApp hydrolases that are widely distributed across bacterial phyla and found in diverse genomic contexts, and we demonstrate that 12 representative members hydrolyze ppApp. In addition, our in silico analyses reveal a unique molecular signature that is specific to (p)ppApp hydrolases, and we show that mutation of two residues within this signature broadens the specificity of Aph1 to promiscuously hydrolyze (p)ppGpp in vitro. Overall, our findings indicate that like (p)ppGpp hydrolases, (p)ppApp hydrolases are widespread in bacteria and may play important and underappreciated role(s) in bacterial physiology.

An interbacterial toxin inhibits target cell growth by synthesizing (p)ppApp.

Bacteria have evolved sophisticated mechanisms to inhibit the growth of competitors1. One such mechanism involves type VI secretion systems, which bacteria can use to inject antibacterial toxins directly into neighbouring cells. Many of these toxins target the integrity of the cell envelope, but the full range of growth inhibitory mechanisms remains unknown2. Here we identify a type VI secretion effector, Tas1, in the opportunistic pathogen Pseudomonas aeruginosa. The crystal structure of Tas1 shows that it is similar to enzymes that synthesize (p)ppGpp, a broadly conserved signalling molecule in bacteria that modulates cell growth rate, particularly in response to nutritional stress3. However, Tas1 does not synthesize (p)ppGpp; instead, it pyrophosphorylates adenosine nucleotides to produce (p)ppApp at rates of nearly 180,000 molecules per minute. Consequently, the delivery of Tas1 into competitor cells drives rapid accumulation of (p)ppApp, depletion of ATP, and widespread dysregulation of essential metabolic pathways, thereby resulting in target cell death. Our findings reveal a previously undescribed mechanism for interbacterial antagonism and demonstrate a physiological role for the metabolite (p)ppApp in bacteria.

Reconstitution of the S. aureus agr quorum sensing pathway reveals a direct role for the integral membrane protease MroQ in pheromone biosynthesis.

In Staphylococcus aureus, virulence is under the control of a quorum sensing (QS) circuit encoded in the accessory gene regulator (agr) genomic locus. Key to this pathogenic behavior is the production and signaling activity of a secreted pheromone, the autoinducing peptide (AIP), generated following the ribosomal synthesis and posttranslational modification of a precursor polypeptide, AgrD, through two discrete cleavage steps. The integral membrane protease AgrB is known to catalyze the first processing event, generating the AIP biosynthetic intermediate, AgrD (1-32) thiolactone. However, the identity of the second protease in this biosynthetic pathway, which removes an N-terminal leader sequence, has remained ambiguous. Here, we show that membrane protease regulator of agr QS (MroQ), an integral membrane protease recently implicated in the agr response, is directly involved in AIP production. Genetic complementation and biochemical experiments reveal that MroQ proteolytic activity is required for AIP biosynthesis in agr specificity group I and group II, but not group III. Notably, as part of this effort, the biosynthesis and AIP-sensing arms of the QS circuit were reconstituted together in vitro. Our experiments also reveal the molecular features guiding MroQ cleavage activity, a critical factor in defining agr specificity group identity. Collectively, our study adds to the molecular understanding of the agr response and Staphylococcus aureus virulence.

Integrated multi-omics analysis and machine learning developed diagnostic markers and prognostic model based on Efferocytosis-associated signatures for septic cardiomyopathy.

Septic cardiomyopathy (SCM) is characterized by an abnormal inflammatory response and increased mortality. The role of efferocytosis in SCM is not well understood. We used integrated multi-omics analysis to explore the clinical and genetic roles of efferocytosis in SCM. We identified six module genes (ATP11C, CD36, CEBPB, MAPK3, MAPKAPK2, PECAM1) strongly associated with SCM, leading to an accurate predictive model. Subgroups defined by EFFscore exhibited distinct clinical features and immune infiltration levels. Survival analysis showed that the C1 subtype with a lower EFFscore had better survival outcomes. scRNA-seq analysis of peripheral blood mononuclear cells (PBMCs) from sepsis patients identified four genes (CEBPB, CD36, PECAM1, MAPKAPK2) associated with high EFFscores, highlighting their role in SCM. Molecular docking confirmed interactions between diagnostic genes and tamibarotene. Experimental validation supported our computational results. In conclusion, our study identifies a novel efferocytosis-related SCM subtype and diagnostic biomarkers, offering new insights for clinical diagnosis and therapy.

Immune to temperature interference sensor of carbon dioxide gas concentration based on a single modified fiber Bragg grating.

In this study, a novel method that can detect carbon dioxide (CO2) concentration and realize temperature immunity based on only one fiber Bragg grating (FBG) is proposed. The outstanding contribution lies in solving the temperature crosstalk issue of FBG and ensuring the accuracy of detection results under the condition of anti-temperature interference. To achieve immunity to temperature interference without changing the initial structure of FBG, the optical fiber cladding of FBG and adjacent optical fiber cladding at both ends of FBG are modified by a polymer coating. Moreover, a universal immune temperature demodulation algorithm is derived. The experimental results demonstrate that the temperature response sensitivity of the improved FBG is controlled within the range of 0.00407 nm/°C. Compared with the initial FBG (the temperature sensitivity of the initial FBG is 0.04 nm/°C), it decreases by nearly 10 times. Besides, the gas response sensitivity of FBG reaches 1.6 pm/ppm and has overwhelmingly ideal linearity. The detection error results manifest that the gas concentration error in 20 groups of data does not exceed 3.16 ppm. The final reproducibility research shows that the difference in detection sensitivity between the two sensors is 0.08 pm/ppm, and the relative error of linearity is 1.07%. In a word, the proposed method can accurately detect the concentration of CO2 gas and is efficiently immune to temperature interference. The sensor we proposed has the advantages of a simple production process, low cost, and satisfactory reproducibility. It also has the prospect of mass production.

Observation of Photoassociation Resonances in Ultracold Atom-Molecule Collisions.

We report on the observation of photoassociation resonances in ultracold collisions between ^{23}Na^{40}K molecules and ^{40}K atoms. We perform photoassociation in a long-wavelength optical dipole trap to form deeply bound triatomic molecules in electronically excited states. The atom-molecule Feshbach resonance is used to enhance the free-bound Franck-Condon overlap. The photoassociation into well-defined quantum states of excited triatomic molecules is identified by observing resonantly enhanced loss features. These loss features depend on the polarization of the photoassociation lasers, allowing us to assign rotational quantum numbers. The observation of ultracold atom-molecule photoassociation resonances paves the way toward preparing ground-state triatomic molecules, provides a new high-resolution spectroscopy technique for polyatomic molecules, and is also important to atom-molecule Feshbach resonances.

Effectiveness of Molnupiravir and Nirmatrelvir-Ritonavir in Hospitalized Patients With COVID-19 : A Target Trial Emulation Study.

BACKGROUND: Whether hospitalized patients benefit from COVID-19 oral antivirals is uncertain. OBJECTIVE: To examine the real-world effectiveness of molnupiravir and nirmatrelvir-ritonavir in hospitalized patients with COVID-19 during the Omicron outbreak. DESIGN: Target trial emulation study. SETTING: Electronic health databases in Hong Kong. PARTICIPANTS: The molnupiravir emulated trial included hospitalized patients with COVID-19 aged 18 years or older between 26 February and 18 July 2022 (n = 16 495). The nirmatrelvir-ritonavir emulated trial included hospitalized patients with COVID-19 aged 18 years or older between 16 March and 18 July 2022 (n = 7119). INTERVENTION: Initiation of molnupiravir or nirmatrelvir-ritonavir within 5 days of hospitalization with COVID-19 versus no initiation of molnupiravir or nirmatrelvir-ritonavir. MEASUREMENTS: Effectiveness against all-cause mortality, intensive care unit (ICU) admission, or use of ventilatory support within 28 days. RESULTS: The use of oral antivirals in hospitalized patients with COVID-19 was associated with a lower risk for all-cause mortality (molnupiravir: hazard ratio [HR], 0.87 [95% CI, 0.81 to 0.93]; nirmatrelvir-ritonavir: HR, 0.77 [CI, 0.66 to 0.90]) but no significant risk reduction in terms of ICU admission (molnupiravir: HR, 1.02 [CI, 0.76 to 1.36]; nirmatrelvir-ritonavir: HR, 1.08 [CI, 0.58 to 2.02]) or the need for ventilatory support (molnupiravir: HR, 1.07 [CI, 0.89 to 1.30]; nirmatrelvir-ritonavir: HR, 1.03 [CI, 0.70 to 1.52]). There was no significant interaction between drug treatment and the number of COVID-19 vaccine doses received, thereby supporting the effectiveness of oral antivirals regardless of vaccination status. No significant interaction between nirmatrelvir-ritonavir treatment and age, sex, or Charlson Comorbidity Index was observed, whereas molnupiravir tended to be more effective in older people. LIMITATION: The outcome of ICU admission or need for ventilatory support may not capture all severe COVID-19 cases; unmeasured confounders, such as obesity and health behaviors, may exist. CONCLUSION: Molnupiravir and nirmatrelvir-ritonavir reduced all-cause mortality in both vaccinated and unvaccinated hospitalized patients. No significant reduction in ICU admission or the need for ventilatory support was observed. PRIMARY FUNDING SOURCE: Health and Medical Research Fund Research on COVID-19, Government of the Hong Kong Special Administrative Region; Research Grants Council, Collaborative Research Fund; and Health Bureau, Government of the Hong Kong Special Administrative Region.

Ammonia storage and slip under steady and transient state in close-coupled SCR.

The close-coupled selective catalytic reduction (cc-SCR) catalyst is an effective technology to reduce tailpipe NOx emission during cold start. This paper investigated the optimal ammonia storage under steady and transient state in the cc-SCR. The study showed that a trade-off between NOx conversion efficiency and ammonia slip is observed on the pareto solutions under steady state, and the optimal ammonia storage is calculated with ammonia slip less than 10 µL/L based on the China Ⅵ emission legislation. The rapid temperature increase will lead to severe ammonia slip in the transient test cycle. A simplified 0-D calculation method on ammonia slip under transient state is proposed based on kinetic model of ammonia adsorption and desorption. In addition, the effect of ammonia storage, catalyst temperature and temperature increasing rate on ammonia slip are analyzed. The optimal ammonia storage is calculated with maximum ammonia slip less than 100 µL/L according to the oxidation efficiency of ammonia slip catalyst (ASC) downstream cc-SCR. It was found that the optimal ammonia storage under transient state is much lower than that under steady state in cc-SCR at lower temperature, and a phase diagram is established to analyze the influence of temperature and temperature increasing rate on optimal ammonia storage.

Data-Driven Controlled Synthesis of Oriented Quasi-Spherical CsPbBr3 Perovskite Materials.

Controlled synthesis of lead-halide perovskite crystals is challenging yet attractive because of the pivotal role played by the crystal structure and growth conditions in regulating their properties. This study introduces data-driven strategies for the controlled synthesis of oriented quasi-spherical CsPbBr3, alongside an investigation into the synthesis mechanism. High-throughput rapid characterization of absorption spectra and color under ultraviolet illumination was conducted using 23 possible ligands for the synthesis of CsPbBr3 crystals. The links between the absorption spectra slope (difference in the absorbance at 400 nm and 450 nm divided by a wavelength interval of 50 nm) and crystal size were determined through statistical analysis of more than 100 related publications. Big data analysis and machine learning were employed to investigate a total of 688 absorption spectra and 652 color values, revealing correlations between synthesis parameters and properties. Ex situ characterization confirmed successful synthesis of oriented quasi-spherical CsPbBr3 perovskites using polyvinylpyrrolidone and Acacia. Density functional theory calculations highlighted strong adsorption of Acacia on the (110) facet of CsPbBr3. Optical properties of the oriented quasi-spherical perovskites prepared with these data-driven strategies were significantly improved. This study demonstrates that data-driven controlled synthesis facilitates morphology-controlled perovskites with excellent optical properties.

CircRNA/lncRNA-miRNA-mRNA network and gene landscape in calcific aortic valve disease.

BACKGROUND: Calcific aortic valve disease (CAVD) is a common valve disease with an increasing incidence, but no effective drugs as of yet. With the development of sequencing technology, non-coding RNAs have been found to play roles in many diseases as well as CAVD, but no circRNA/lncRNA-miRNA-mRNA interaction axis has been established. Moreover, valve interstitial cells (VICs) and valvular endothelial cells (VECs) play important roles in CAVD, and CAVD differed between leaflet phenotypes and genders. This work aims to explore the mechanism of circRNA/lncRNA-miRNA-mRNA network in CAVD, and perform subgroup analysis on the important characteristics of CAVD, such as key cells, leaflet phenotypes and genders. RESULTS: We identified 158 differentially expressed circRNAs (DEcircRNAs), 397 DElncRNAs, 45 DEmiRNAs and 167 DEmRNAs, and constructed a hsa-circ-0073813/hsa-circ-0027587-hsa-miR-525-5p-SPP1/HMOX1/CD28 network in CAVD after qRT-PCR verification. Additionally, 17 differentially expressed genes (DEGs) in VICs, 9 DEGs in VECs, 7 DEGs between different leaflet phenotypes and 24 DEGs between different genders were identified. Enrichment analysis suggested the potentially important pathways in inflammation and fibro-calcification during the pathogenesis of CAVD, and immune cell patterns in CAVD suggest that M0 macrophages and memory B cells memory were significantly increased, and many genes in immune cells were also differently expressed. CONCLUSIONS: The circRNA/lncRNA-miRNA-mRNA interaction axis constructed in this work and the DEGs identified between different characteristics of CAVD provide a direction for a deeper understanding of CAVD and provide possible diagnostic markers and treatment targets for CAVD in the future.

Long-term effects of coronavirus disease 2019 on diabetes complications and mortality in people with diabetes: Two cohorts in the UK and Hong Kong.

AIM: To evaluate the long-term associations between coronavirus disease 2019 (COVID-19) and diabetes complications and mortality, in patients with diabetes. MATERIALS AND METHODS: People with diabetes diagnosed with COVID-19 infection (exposed group), from 16 March 2020 to 31 May 2021 from the UK Biobank (UKB cohort; n = 2456), and from 1 April 2020 to 31 May 2022 from the electronic health records in Hong Kong (HK cohort; n = 80 546), were recruited. Each patient was randomly matched with participants with diabetes but without COVID-19 (unexposed group), based on age and sex (UKB, n = 41 801; HK, n = 391 849). Patients were followed for up to 18 months until 31 August 2021 for UKB, and up to 28 months until 15 August 2022 for HK. Characteristics between cohorts were further adjusted with Inverse Probability Treatment Weighting. Long-term association of COVID-19 with multi-organ disease complications and all-cause mortality after 21 days of diagnosis was evaluated by Cox regression. RESULTS: Compared with uninfected participants, patients with COVID-19 infection with diabetes were consistently associated with higher risks of cardiovascular diseases (coronary heart disease [CHD]: hazard ratio [HR] [UKB]: 1.6 [95% confidence interval {CI}: 1.0, 2.4], HR [HK]: 1.2 [95% CI: 1.0, 1.5]; and stroke: HR [UKB]: 2.0 [95% CI: 1.1, 3.6], HR [HK]: 1.5 [95% CI: 1.3, 1.8]), microvascular disease (end stage renal disease: HR [UKB]: 2.1 [95% CI: 1.1, 4.0], HR [HK]: 1.2 [95% CI: 1.1, 1.4]) and all-cause mortality (HR [UKB]: 4.6 [95% CI: 3.8, 5.5], HR [HK]: 2.6 [95% CI: 2.5, 2.8]), in both cohorts. CONCLUSIONS: COVID-19 infection is associated with long-term increased risks of diabetes complications (especially cardiovascular complications, and mortality) in people with diabetes. Monitoring for signs/symptoms of developing these long-term complications post-COVID-19 infection in the infected patient population of people with diabetes may be beneficial in minimizing their morbidity and mortality.

ALDH3A1 overexpression in OSCC inhibits inflammation via phospho-Ser727 at STAT3 in tumor-associated macrophages.

OBJECTIVES: Cancer-related inflammation (CRI) significantly increases the difficulty of treating oral squamous cell carcinoma (OSCC) and remains a major treatment challenge. Our objective was to determine whether tumor ALDH3A1 could attenuate OSCC tumorigenesis by inhibiting tumor-associated macrophages (TAMs) that promoted CRI. MATERIALS AND METHODS: ALDH3A1 in Cal27 cells was overexpressed, and the tumor-conditioned medium (TCM) was collected. We induced THP-1 cells with TCM and recombinant human IL-6. The phosphorylation of STAT3 and the TLR4/TRAF6/TBK1 cascade reaction in TAMs was analyzed using Western blotting, and mitochondrial ROS (mtROS) production was measured using a MitoSox kit. A tumorigenicity assay was performed to examine the tumor volume and weight, and the expression of CD68, CD11b, IL-6, Ki67, and CD31 was analyzed via immunohistochemistry. RESULTS: ALDH3A1 attenuated STAT3 phosphorylation at Ser727 rapidly and mtROS production earlier in TAMs via inhibiting TLR4/TRAF6/TBK1 cascade reaction. MtROS reduction inhibited IL-1ß and IL-8 secretions by NLRP3/caspase-1/IL-1ß/IL-8 pathway. Meanwhile, the inhibition of pro-tumor phenotypes of TAMs, tumor proliferation, and tumor angiogenesis during the process was proved in vivo. CONCLUSION: ALDH3A1 was associated closely with CRI and inhibited CRI regulated by TAMs. This finding may achieve clinical transformation and open new therapeutic options for targeting CRI regulated by TAMs.

Evaluation of the Risk Factors for Cellulitis among Patients with Peripheral Artery Disease.

Background and objectives: The objective of this study is to elucidate peripheral occlusion artery disease (PAOD) as a risk factor for cellulitis. Materials and Methods: This is a retrospective population-based cohort study. The database is the Longitudinal Health Insurance Database, which covers two million beneficiaries from the entire population of the 2010 registry for beneficiaries in Taiwan. The PAOD group is composed of patients who were newly diagnosed with PAOD from 2001 to 2014. The non-PAOD group is composed of patients who were never diagnosed with PAOD from 2001 to 2015. All patients were followed until the onset of cellulitis, death, or until the end of 2015. Results: Finally, 29,830 patients who were newly diagnosed with PAOD were included in the PAOD group, and 29,830 patients who were never diagnosed with PAOD were included in the non-PAOD group. The incidence densities (ID) of cellulitis were 26.05 (95% CI = 25.31-26.80) patients per 1000 person-years in the PAOD group and 49.10 (95% CI = 48.04-50.19) in the non-PAOD group. The PAOD group had an increased risk of cellulitis (adjusted HR = 1.94, 95% CI = 1.87-2.01) compared to the non-PAOD group. Conclusions: Patients with PAOD were associated with a higher risk of subsequent cellulitis compared to patients without PAOD.

Activation and inhibition of the receptor histidine kinase AgrC occurs through opposite helical transduction motions.

Staphylococcus aureus virulence is regulated when secreted autoinducing peptides (AIPs) are recognized by a membrane-bound receptor histidine kinase (RHK), AgrC. Some AIPs are agonists of virulence gene expression, while others are antagonists. It is unclear how AIP binding regulates AgrC activity. Here, we reconstitute an AgrC family member, AgrC-I, using nanometer-scale lipid bilayer discs. We show that AgrC-I requires membranes rich in anionic lipids to function. The agonist, AIP-I, binds AgrC-I noncooperatively in a 2:2 stoichiometry, while an antagonist ligand, AIP-II, functions as an inverse agonist of the kinase activity. We also demonstrate the kinase and sensor domains in AgrC are connected by a helical linker whose conformational state exercises rheostat-like control over the kinase activity. Binding of agonist or inverse-agonist peptides results in twisting of the linker in different directions. These two observations provide a view of the molecular motions triggered by ligand binding in an intact membrane-bound RHK.

[Analysis of CiteSpace knowledge map for traditional Chinese medicine prevention and treatment of cerebral small vessel diseases].

This study aims to analyze the research on the prevention and treatment of cerebral small vessel diseases(CSVDs) with traditional Chinese medicine(TCM) based on knowledge map, and to preliminarily explore the research hotspots and trends. To be specific, articles on TCM treatment of CSVDs in CNKI, Wanfang, and VIP(from establishment to November 2021) were retrieved, followed by bibliometric analysis. Then CiteSpace 5.7 R4 and Gephi were employed for generation of maps on annual number of articles, author cooperation, institution cooperation, keyword co-occurrence, keyword clustering, and keyword emergence. A total of 106 eligible articles were screened out, and the annual number of articles presented a steady upward trend. A total of 277 authors were included in the author cooperation network, among whom CHEN Zhigang published the most articles. A total of 87 institutions were included in the institution cooperation network, among which Dongfang Hospital of Beijing University of Chinese Medicine showed the most frequent cooperation with other institutions. Keyword clustering showed that research on the TCM treatment of CSVDs mainly focused on five aspects: related disease research, neurological function deficits, disease nature and location in TCM, TCM treatment methods, and formulas. The prevention and treatment of CSVDs with TCM in China has been developing steadily in the past ten years, and TCM has unique advantages in the prevention and treatment of this disease. The knowledge maps vividly demonstrated the development and research hotspots and trends in this field. The result is expected to provide a reference for further research in this field.

Bortezomib alleviates myocardial ischemia reperfusion injury via enhancing of Nrf2/HO-1 signaling pathway.

Bortezomib is a classical proteasome inhibitor and previous researches have reported its roles of anti-oxidation and anti-inflammatory functions in various diseases. However, the role of Bortezomib in myocardial ischemia reperfusion injury (MIRI) is unclear. Thus, our research seeks to reveal the protective effects of Bortezomib pretreatment in the mice model of MIRI. First, by the optimization of Bortezomib concentration and pretreatment timepoints, we found that 0.5 mg/kg Bortezomib pretreatment 2 h before MIRI significantly attenuated pathological damage and neutrophil infiltration. Then we found that pretreatment with Bortezomib obviously increased myocardial systolic function ((left ventricular ejection fraction (LVEF) and left ventricular fractional shortening (LVFS)) and decreased infarct size, as well as serum Troponin T levels. Meanwhile, Bortezomib pretreatment also remarkably augmented oxidative stress related protein levels of Superoxide dismutase [Cu-Zn] (SOD1), Catalase (CAT) and Glutathione (GSH), while reactive oxygen species (ROS) contents and Malonaldehyde (MDA) protein level were significantly reduced. Mechanistically, Bortezomib pretreatment significantly promoted nuclear translocation of transcriptional factor nuclear factor erythroid 2-related factor 2(Nrf2) and Heme Oxygenase 1(HO-1) expression. Interestingly, co-treatment with ML-385, a new type and selective Nrf2 inhibitor, counteracted antioxidative effects induced by Bortezomib pretreatment. In conclusion, Bortezomib pretreatment mitigates MIRI by inhibiting oxidative damage which is regulated by Nrf2/HO-1 signaling pathway.

Author Correction: Affinity-based capture and identification of protein effectors of the growth regulator ppGpp.

In the version of the article originally published, two sets of labels on the x axis of the graph in Fig. 5b were in reverse order. In the 'PurF' row, the locations of 'N48A' and 'R45A' should be switched, and in the row below those of '4.1' and the minus sign should be switched. Shown below are the original and corrected versions of Fig. 5b. The error has been corrected in the HTML and PDF versions of the article.

Affinity-based capture and identification of protein effectors of the growth regulator ppGpp.

The nucleotide ppGpp is a highly conserved regulatory molecule in bacteria that helps tune growth rate to nutrient availability. Despite decades of study, how ppGpp regulates growth remains poorly understood. Here, we developed and validated a capture-compound mass spectrometry approach that identified >50 putative ppGpp targets in Escherichia coli. These targets control many key cellular processes and include 13 enzymes required for nucleotide synthesis. We demonstrated that ppGpp inhibits the de novo synthesis of all purine nucleotides by directly targeting the enzyme PurF. By solving a structure of PurF bound to ppGpp, we designed a mutation that ablates ppGpp-based regulation, leading to dysregulation of purine-nucleotide synthesis following ppGpp accumulation. Collectively, our results provide new insights into ppGpp-based growth control and a nearly comprehensive set of targets for future exploration. The capture compounds developed should also enable the rapid identification of ppGpp targets in any species, including pathogens.