Cryo-EM Structure of an Extended SARS-CoV-2 Replication and Transcription Complex Reveals an Intermediate State in Cap Synthesis.

Transcription of SARS-CoV-2 mRNA requires sequential reactions facilitated by the replication and transcription complex (RTC). Here, we present a structural snapshot of SARS-CoV-2 RTC as it transitions toward cap structure synthesis. We determine the atomic cryo-EM structure of an extended RTC assembled by nsp7-nsp82-nsp12-nsp132-RNA and a single RNA-binding protein, nsp9. Nsp9 binds tightly to nsp12 (RdRp) NiRAN, allowing nsp9 N terminus inserting into the catalytic center of nsp12 NiRAN, which then inhibits activity. We also show that nsp12 NiRAN possesses guanylyltransferase activity, catalyzing the formation of cap core structure (GpppA). The orientation of nsp13 that anchors the 5' extension of template RNA shows a remarkable conformational shift, resulting in zinc finger 3 of its ZBD inserting into a minor groove of paired template-primer RNA. These results reason an intermediate state of RTC toward mRNA synthesis, pave a way to understand the RTC architecture, and provide a target for antiviral development.

Optimization of Extraction Process and Analysis of Biological Activity of Flavonoids from Leaves of Cultivated 'Qi-Nan' Agarwood.

Currently, the planting of 'Qi-Nan' is continuously increasing, yet a substantial amount of 'Qi-Nan' leaves have not been properly exploited. To improve the 'Qi-Nan' tree 's utilization value, 'Qi-Nan' leaves were used as a raw material. An ultrasound-assisted method was performed to obtain the flavonoids from the 'Qi-Nan' leaves, followed by optimization of the extraction factors using a one-way and response surface methodology to enhance the extraction of flavonoids. Subsequently, the composition of the flavonoids, as well as their bioactive abilities, were analyzed by ultra-high-performance liquid chromatography-mass spectrometry (UHPLC-MS) and in vitro activity testing methods. The findings demonstrated that a 1:50 material-to-liquid ratio, 60% ethanol concentration, and ultrasound-assisted extraction time of 30 min were the ideal procedures for extracting flavonoids (flavonoid content: 6.68%). Meanwhile, the 'Qi-Nan' leaves possessed the antioxidant and medicinal potential to prevent diabetes and Alzheimer 's disease, as evidenced by the semi-inhibitory concentrations (IC50 values) of flavonoid extracts for scavenging DPPH• free radicals, scavenging ABTS•+ free radicals, inhibiting acetylcholinesterase, and inhibiting α-glucosidase, which were 12.64 µg/mL, 66.58 µg/mL, 102.31 µg/mL, and 38.76 µg/mL, respectively, which indicated that the 'Qi-Nan' leaves possessed the properties of antioxidant and medicinal potential for the prevention of Alzheimer 's disease and diabetes.

Measuring the Pseudocapacitive Behavior of Individual V2O5 Particles by Scanning Electrochemical Cell Microscopy.

V2O5 is a promising pseudocapacitive material for electrochemical energy storage with balanced power and energy density. Understanding the charge-storage mechanism is of significance to further improve the rate performance. Here, we report an electrochemical study of individual V2O5 particles using scanning electrochemical cell microscopy with colocalized electron microscopy. A carbon sputtering procedure is proposed for the pristine V2O5 particles to improve their structure stability and electronic conductivity. The achieved high-quality electrochemical cyclic voltammetry results, structural integrity, and high oxidation to reduction charge ratio (as high as 97.74%) assured further quantitative analysis of the pseudocapacitive behavior of single particles and correlation with local particle structures. A broad range of capacitive contribution is revealed, with an average ratio of 76% at 1.0 V/s. This study provides new opportunities for quantitative analysis of the electrochemical charge-storage process at single particles, especially for electrode materials with electrolyte-induced instability.

How Closely Does Induced Agarwood's Biological Activity Resemble That of Wild Agarwood?

Continuous innovation in artificially-induced agarwood technology is increasing the amount of agarwood and substantially alleviating shortages. Agarwood is widely utilized in perfumes and fragrances; however, it is unclear whether the overall pharmacological activity of induced agarwood can replace wild agarwood for medicinal use. In this study, the volatile components, total chromone content, and the differences in the overall activities of wild agarwood and induced agarwood, including the antioxidant, anti-acetylcholinesterase, and anti-glucosidase activity were all determined. The results indicated that both induced and wild agarwood's chemical makeup contains sesquiterpenes and 2-(2-phenylethyl)chromones. The total chromone content in generated agarwood can reach 82.96% of that in wild agarwood. Induced agarwood scavenged 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS+) radicals and inhibited acetylcholinesterase activity and α-glucosidase activity with IC50 values of 0.1873 mg/mL, 0.0602 mg/mL, 0.0493 mg/mL, and 0.2119 mg/mL, respectively, reaching 80.89%, 93.52%, 93.52%, and 69.47% of that of wild agarwood, respectively. Accordingly, the results distinguished that induced agarwood has the potential to replace wild agarwood in future for use in medicine because it has a similar chemical makeup to wild agarwood and has comparable antioxidant, anti-acetylcholinesterase, and anti-glucosidase capabilities.

Electrostatic Attraction-Driven Assembly of a Metal-Organic Framework with a Photosensitizer Boosts Photocatalytic CO2 Reduction to CO.

Reducing CO2 into fuels via photochemical reactions relies on highly efficient photocatalytic systems. Herein, we report a new and efficient photocatalytic system for CO2 reduction. Driven by electrostatic attraction, an anionic metal-organic framework Cu-HHTP (HHTP = 2,3,6,7,10,11-hexahydroxytriphenylene) as host and a cationic photosensitizer [Ru(phen)3]2+ (phen = 1,10-phenanthroline) as guest were self-assembled into a photocatalytic system Ru@Cu-HHTP, which showed high activity for photocatalytic CO2 reduction under laboratory light source (CO production rate of 130(5) mmol g-1 h-1, selectivity of 92.9%) or natural sunlight (CO production rate of 69.5 mmol g-1 h-1, selectivity of 91.3%), representing the remarkable photocatalytic CO2 reduction performance. More importantly, the photosensitizer [Ru(phen)3]2+ in Ru@Cu-HHTP is only about 1/500 in quantity reported in the literature. Theoretical calculations and control experiments suggested that the assembly of the catalysts and photosensitizers via electrostatic attraction interactions can provide a better charge transfer efficiency, resulting in high performance for photocatalytic CO2 reduction.

The Effects of Curing and Casting Methods on the Physicochemical Properties of Polymer Films.

Most film coatings in the pharmaceutical industry are prepared using organic solvents or aqueous solvents. Due to different film-formation mechanisms, their properties are significantly different from each other. Curing can alter the microstructure of films by improving the coalescence of polymer particles for aqueous dispersion-based films or accelerating macromolecule relaxation for organic solvent-based films. The aim of this study was to investigate the effects of preparation methods and curing on the physicochemical properties of Kollicoat® SR30D and Kollicoat® MAE100P films. The film's properties, including water diffusion coefficient, mechanical properties, plasticizer loss, swelling behavior, and contact angle, were measured for uncured or cured aqueous dispersion-based or organic solvent-based films. The results indicated that curing decreased water diffusivities in films and increased film's tensile strength. Curing resulted in plasticizer loss from SR30D films but not from MAE100P films due to strong interaction between plasticizer and MAE100P. The surface of organic solvent-based films was more hydrophobic than that of aqueous dispersion-based films. The contact angle of organic solvent-based films was increased after curing possibly because curing decreased roughness of the film surface. Organic solvent-based SR30D films had better mechanical properties than the corresponding aqueous dispersion-based films because of higher degree of polymer-polymer entanglement in the organic solvent-based films. However, contradictory phenomena were observed in MAE100P films possibly due to a "core-shell" structure reserved in the aqueous dispersion-based MAE100P films. In summary, casting methods and curing have significant impact on the film properties due to different film structures, coalescence, or film relaxation, and other concurrent effects including evaporation of residue solvent and plasticizers.

Mutual antagonism of Wilms' tumor 1 and ß-catenin dictates podocyte health and disease.

Activation of ß-catenin, the intracellular mediator of canonical Wnt signaling, has a critical role in mediating podocyte injury and proteinuria. However, the underlying mechanisms remain poorly understood. Here, we show that ß-catenin triggers ubiquitin-mediated protein degradation of Wilms' tumor 1 (WT1) and functionally antagonizes its action. In mice injected with adriamycin, WT1 protein was progressively lost in glomerular podocytes at 1, 3, and 5 weeks after injection. Notably, loss of WT1 apparently did not result from podocyte depletion but was closely associated with upregulation of ß-catenin. This change in WT1/ß-catenin ratio was accompanied by loss of podocyte-specific nephrin, podocalyxin, and synaptopodin and acquisition of mesenchymal markers Snail1, α-smooth muscle actin, and fibroblast-specific protein 1. In vitro, overexpression of ß-catenin induced WT1 protein degradation through the ubiquitin proteasomal pathway, which was blocked by MG-132. WT1 and ß-catenin also competed for binding to common transcriptional coactivator CREB-binding protein and mutually repressed the expression of their respective target genes. In glomerular miniorgan culture, activation of ß-catenin by Wnt3a repressed WT1 and its target gene expression. In vivo, blockade of Wnt/ß-catenin signaling by endogenous antagonist Klotho induced WT1 and restored podocyte integrity in adriamycin nephropathy. These results show that ß-catenin specifically targets WT1 for ubiquitin-mediated degradation, leading to podocyte dedifferentiation and mesenchymal transition. Our data also suggest that WT1 and ß-catenin have opposing roles in podocyte biology, and that the ratio of their expression levels dictates the state of podocyte health and disease in vivo.

Multiple genes of the renin-angiotensin system are novel targets of Wnt/ß-catenin signaling.

Activation of the renin-angiotensin system (RAS) plays an essential role in the pathogenesis of CKD and cardiovascular disease. However, current anti-RAS therapy only has limited efficacy, partly because of compensatory upregulation of renin expression. Therefore, a treatment strategy to simultaneously target multiple RAS genes is necessary to achieve greater efficacy. By bioinformatics analyses, we discovered that the promoter regions of all RAS genes contained putative T-cell factor (TCF)/lymphoid enhancer factor (LEF)-binding sites, and ß-catenin induced the binding of LEF-1 to these sites in kidney tubular cells. Overexpression of either ß-catenin or different Wnt ligands induced the expression of all RAS genes. Conversely, a small-molecule ß-catenin inhibitor ICG-001 abolished RAS induction. In a mouse model of nephropathy induced by adriamycin, either transient therapy or late administration of ICG-001 abolished established proteinuria and kidney lesions. ICG-001 inhibited renal expression of multiple RAS genes in vivo and abolished the expression of other Wnt/ß-catenin target genes. Moreover, ICG-001 therapy restored expression of nephrin, podocin, and Wilms' tumor 1, attenuated interstitial myofibroblast activation, repressed matrix expression, and inhibited renal inflammation and fibrosis. Collectively, these studies identify all RAS genes as novel downstream targets of Wnt/ß-catenin. Our results indicate that blockade of Wnt/ß-catenin signaling can simultaneously repress multiple RAS genes, thereby leading to the reversal of established proteinuria and kidney injury.

Extracellular Superoxide Dismutase Protects against Proteinuric Kidney Disease.

Extracellular superoxide dismutase (EC-SOD), also known as SOD3, is an antioxidant expressed at high levels in normal adult kidneys. Because oxidative stress contributes to a variety of kidney injuries, we hypothesized that EC-SOD may be protective in CKD progression. To study this hypothesis, we used a murine model of ADR nephropathy characterized by albuminuria and renal dysfunction. We found that levels of EC-SOD diminished throughout the course of disease progression and were associated with increased levels of NADPH oxidase and oxidative stress markers. EC-SOD null mice were sensitized to ADR injury, as evidenced by increases in albuminuria, serum creatinine, histologic damage, and oxidative stress. The absence of EC-SOD led to increased levels of NADPH oxidase and an increase in ß-catenin signaling, which has been shown to be pathologic in a variety of kidney injuries. Exposure of EC-SOD null mice to either chronic angiotensin II infusion or to daily albumin injections also caused increased proteinuria. In contrast, EC-SOD null mice subjected to nonproteinuric CKD induced by unilateral ureteral obstruction exhibited no differences compared with wild-type mice. Finally, we also found a decrease in EC-SOD in human CKD biopsy samples, similar to our findings in mice. Therefore, we conclude that EC-SOD is protective in CKDs characterized by proteinuria.

Sonic hedgehog is a novel tubule-derived growth factor for interstitial fibroblasts after kidney injury.

Tubular epithelium constitutes the majority of the renal parenchyma and is the primary target of various kidney injuries. However, how the injured tubules drive interstitial fibroblast activation and proliferation remains poorly understood. Here, we investigated the role of sonic hedgehog (Shh), a secreted extracellular signaling protein, in fibroblast proliferation. Shh was induced in renal tubular epithelia in animal models of CKD induced by ischemia/reperfusion injury (IRI), adriamycin, or renal mass ablation, and in renal tubules of kidney biopsy specimens from CKD patients with different etiologies. Using Gli1-CreER(T2) reporter mice, we identified interstitial fibroblasts as the principal targets of renal Shh signaling in vivo. In vitro, incubation with Shh promoted normal rat kidney fibroblast proliferation, which was assessed by cell counting, MTT assay, and BrdU incorporation assay, and stimulated the induction of numerous proliferation-related genes. However, Shh had no effect on the proliferation of renal tubular epithelial cells. In vivo, overexpression of Shh promoted fibroblast expansion and aggravated kidney fibrotic lesions after IRI. Correspondingly, blockade of Shh signaling by cyclopamine, a small molecule inhibitor of Smoothened, inhibited fibroblast proliferation, reduced myofibroblast accumulation, and attenuated renal fibrosis. These studies identify Shh as a novel, specific, and potent tubule-derived growth factor that promotes interstitial fibroblast proliferation and activation. Our data also suggest that blockade of Shh signaling is a plausible strategy for therapeutic intervention of renal fibrosis.

Loss of Klotho contributes to kidney injury by derepression of Wnt/ß-catenin signaling.

Aging is an independent risk factor for CKD, but the molecular mechanisms that link aging and CKD are not well understood. The antiaging protein Klotho may be an endogenous antagonist of Wnt/ß-catenin signaling, which promotes fibrogenesis, suggesting that loss of Klotho may contribute to CKD through increased Wnt/ß-catenin activity. Here, normal adult kidneys highly expressed Klotho in the tubular epithelium, but various models of nephropathy exhibited markedly less expression of Klotho. Loss of Klotho was closely associated with increased ß-catenin in the diseased kidneys, suggesting an inverse correlation between Klotho and canonical Wnt signaling. In vitro, both full-length and secreted Klotho bound to multiple Wnts, including Wnt1, Wnt4, and Wnt7a. Klotho repressed gene transcription induced by Wnt but not by active ß-catenin. Furthermore, Klotho blocked Wnt-triggered activation and nuclear translocation of ß-catenin, as well as the expression of its target genes in tubular epithelial cells. Investigating potential mediators of Klotho loss in CKD, we found that TGF-ß1 suppressed Klotho expression and concomitantly activated ß-catenin; conversely, overexpression of Klotho abolished fibrogenic effects of TGF-ß1. In two mouse models of CKD induced by unilateral ureteral obstruction or adriamycin, in vivo expression of secreted Klotho inhibited the activation of renal ß-catenin and expression of its target genes. Secreted Klotho also suppressed myofibroblast activation, reduced matrix expression, and ameliorated renal fibrosis. Taken together, these results suggest that Klotho is an antagonist of endogenous Wnt/ß-catenin activity; therefore, loss of Klotho may contribute to kidney injury by releasing the repression of pathogenic Wnt/ß-catenin signaling.

A method for extracting buildings from remote sensing images based on 3DJA-UNet3.

Building extraction aims to extract building pixels from remote sensing imagery, which plays a significant role in urban planning, dynamic urban monitoring, and many other applications. UNet3+ is widely applied in building extraction from remote sensing images. However, it still faces issues such as low segmentation accuracy, imprecise boundary delineation, and the complexity of network models. Therefore, based on the UNet3+ model, this paper proposes a 3D Joint Attention (3DJA) module that effectively enhances the correlation between local and global features, obtaining more accurate object semantic information and enhancing feature representation. The 3DJA module models semantic interdependence in the vertical and horizontal dimensions to obtain feature map spatial encoding information, as well as in the channel dimensions to increase the correlation between dependent channel graphs. In addition, a bottleneck module is constructed to reduce the number of network parameters and improve model training efficiency. Many experiments are conducted on publicly accessible WHU,INRIA and Massachusetts building dataset, and the benchmarks, BOMSC-Net, CVNet, SCA-Net, SPCL-Net, ACMFNet, MFCF-Net models are selected for comparison with the 3DJA-UNet3+ model proposed in this paper. The experimental results show that 3DJA-UNet3+ achieves competitive results in three evaluation indicators: overall accuracy, mean intersection over union, and F1-score. The code will be available at https://github.com/EnjiLi/3DJA-UNet3Plus .

Controlled preparation of curcumin nanocrystals by detachable stainless steel microfluidic chip.

Microfluidic technology has not been extensively utilized in nanocrystals manufacture, although it has been used in the production of liposomes and LNPs. This is mainly due to concerns including blockage of narrow pipes and corrosion of organic solvents on chips. In this study, a detachable stainless steel microfluidic chip with split-and-recombine (SAR) structure was engraved and used to prepare curcumin nanocrystal suspensions by a microfluidic-antisolvent precipitation method. A simulation study of the mixing activities of three chip structures was conducted by COMSOL Multiphysics software. Then the curcumin nanocrystals preparation was optimized by Box-Behnken design to screen different stabilizers and solvents. Two curcumin nanocrystals formulations with an average particle size of 59.29 nm and 168.40 nm were obtained with PDIs of 0.131 and 0.058, respectively. Compared to curcumin powder, the formulation showed an increase in dissolution rate in 0.1 M HCL while pharmacokinetic study indicated that Cmax was increased by 4.47 and 3.14 times and AUC0-∞ were 4.26 and 3.14 times greater. No clogging or deformation of the chip was observed after long usage. The results demonstrate that the stainless steel microfluidic chips with SAR structure have excellent robustness and controllability. It has the potential to be applied in GMP manufacturing of nanocrystals.

Experimental Research on Gradation Range and Performance of SMAC13.

Stone matrix asphalt and asphalt concrete mixture with 13.2 mm nominal maximum aggregate size (named SMA13 and AC13, respectively) are widely used in the surface course of asphalt pavement in China. Generally, the pavement performance of SMA13 is superior to that of AC13, while the cost of the former is significantly higher than that of the latter. The objective of this paper was to develop a new hot mix asphalt (named SMAC13) whose performance and cost are between SMA13 and AC13. A boundary sieve size (BSS) of 2.36 mm was selected between fine and coarse aggregates. Based on the union set of aggregate gradation ranges of SMA13 and AC13, the family of gradation curves in the forms of S shapes were designed in terms of the BSS passing rate. According to the evaluation of the skeleton interlock of coarse aggregate of the gradation curve family, the aggregate gradation range of SMAC13 was determined. Also, the performance of three kinds of asphalt mixtures were compared through laboratory tests. The results indicated that SMA13 shows the best rutting resistance, followed by SMAC13 then AC13, while in terms of low-temperature performance in resistance to cracking, the sequence is SMAC13, AC13, and SMA13. The sequence of water stability is AC13, SMAC13, and SMA13. Furthermore, the cost of SMAC13 is 25% less than that of SMA13. Therefore, SMAC13 can be used as an alternative for the surface course of asphalt pavement in terms of performance and cost.

An optimized high-throughput SARS-CoV-2 dual reporter trans-complementation system for antiviral screening in vitro and in vivo.

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is still epidemic around the world. The manipulation of SARS-CoV-2 is restricted to biosafety level 3 laboratories (BSL-3). In this study, we developed a SARS-CoV-2 ΔN-GFP-HiBiT replicon delivery particles (RDPs) encoding a dual reporter gene, GFP-HiBiT, capable of producing both GFP signal and luciferase activities. Through optimal selection of the reporter gene, GFP-HiBiT demonstrated superior stability and convenience for antiviral evaluation. Additionally, we established a RDP infection mouse model by delivering the N gene into K18-hACE2 KI mouse through lentivirus. This mouse model supports RDP replication and can be utilized for in vivo antiviral evaluations. In summary, the RDP system serves as a valuable tool for efficient antiviral screening and studying the gene function of SARS-CoV-2. Importantly, this system can be manipulated in BSL-2 laboratories, decreasing the threshold of experimental requirements.

Structural and functional insights into the 2'-O-methyltransferase of SARS-CoV-2.

A unique feature of coronaviruses is their utilization of self-encoded nonstructural protein 16 (nsp16), 2'-O-methyltransferase (2'-O-MTase), to cap their RNAs through ribose 2'-O-methylation modification. This process is crucial for maintaining viral genome stability, facilitating efficient translation, and enabling immune escape. Despite considerable advances in the ultrastructure of SARS-CoV-2 nsp16/nsp10, insights into its molecular mechanism have so far been limited. In this study, we systematically characterized the 2'-O-MTase activity of nsp16 in SARS-CoV-2, focusing on its dependence on nsp10 stimulation. We observed cross-reactivity between nsp16 and nsp10 in various coronaviruses due to a conserved interaction interface. However, a single residue substitution (K58T) in SARS-CoV-2 nsp10 restricted the functional activation of MERS-CoV nsp16. Furthermore, the cofactor nsp10 effectively enhanced the binding of nsp16 to the substrate RNA and the methyl donor S-adenosyl-l-methionine (SAM). Mechanistically, His-80, Lys-93, and Gly-94 of nsp10 interacted with Asp-102, Ser-105, and Asp-106 of nsp16, respectively, thereby effectively stabilizing the SAM binding pocket. Lys-43 of nsp10 interacted with Lys-38 and Gly-39 of nsp16 to dynamically regulate the RNA binding pocket and facilitate precise binding of RNA to the nsp16/nsp10 complex. By assessing the conformational epitopes of nsp16/nsp10 complex, we further determined the critical residues involved in 2'-O-MTase activity. Additionally, we utilized an in vitro biochemical platform to screen potential inhibitors targeting 2'-O-MTase activity. Overall, our results significantly enhance the understanding of viral 2'-O methylation process and mechanism, providing valuable targets for antiviral drug development.

Natural evidence of coronaviral 2'-O-methyltransferase activity affecting viral pathogenesis via improved substrate RNA binding.

Previous studies through targeted mutagenesis of K-D-K-E motif have demonstrated that 2'-O-MTase activity is essential for efficient viral replication and immune evasion. However, the K-D-K-E catalytic motif of 2'-O-MTase is highly conserved across numerous viruses, including flaviviruses, vaccinia viruses, coronaviruses, and extends even to mammals. Here, we observed a stronger 2'-O-MTase activity in SARS-CoV-2 compared to SARS-CoV, despite the presence of a consistently active catalytic center. We further identified critical residues (Leu-36, Asn-138 and Ile-153) which served as determinants of discrepancy in 2'-O-MTase activity between SARS-CoV-2 and SARS-CoV. These residues significantly enhanced the RNA binding affinity of 2'-O-MTase and boosted its versatility toward RNA substrates. Of interest, a triple substitution (Leu36 → Ile36, Asn138 → His138, Ile153 → Leu153, from SARS-CoV-2 to SARS-CoV) within nsp16 resulted in a proportional reduction in viral 2'-O-methylation and impaired viral replication. Furthermore, it led to a significant upregulation of type I interferon (IFN-I) and proinflammatory cytokines both in vitro and vivo, relying on the cooperative sensing of melanoma differentiation-associated protein 5 (MDA5) and laboratory of genetics and physiology 2 (LGP2). In conclusion, our findings demonstrated that alterations in residues other than K-D-K-E of 2'-O-MTase may affect viral replication and subsequently influence pathogenesis. Monitoring changes in nsp16 residues is crucial as it may aid in identifying and assessing future alteration in viral pathogenicity resulting from natural mutations occurring in nsp16.

Epitranscriptomic m5C methylation of SARS-CoV-2 RNA regulates viral replication and the virulence of progeny viruses in the new infection.

While the significance of N6-methyladenosine (m6A) in viral regulation has been extensively studied, the functions of 5-methylcytosine (m5C) modification in viral biology remain largely unexplored. In this study, we demonstrate that m5C is more abundant than m6A in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and provide a comprehensive profile of the m5C landscape of SARS-CoV-2 RNA. Knockout of NSUN2 reduces m5C levels in SARS-CoV-2 virion RNA and enhances viral replication. Nsun2 deficiency mice exhibited higher viral burden and more severe lung tissue damages. Combined RNA-Bis-seq and m5C-MeRIP-seq identified the NSUN2-dependent m5C-methylated cytosines across the positive-sense genomic RNA of SARS-CoV-2, and the mutations of these cytosines enhance RNA stability. The progeny SARS-CoV-2 virions from Nsun2 deficiency mice with low levels of m5C modification exhibited a stronger replication ability. Overall, our findings uncover the vital role played by NSUN2-mediated m5C modification during SARS-CoV-2 replication and propose a host antiviral strategy via epitranscriptomic addition of m5C methylation to SARS-CoV-2 RNA.

Matrix metalloproteinase-7 as a surrogate marker predicts renal Wnt/ß-catenin activity in CKD.

A variety of chronic kidney diseases exhibit reactivation of Wnt/ß-catenin signaling. In some tissues, ß-catenin transcriptionally regulates matrix metalloproteinase-7 (MMP-7), but the association between MMP-7 and Wnt/ß-catenin signaling in chronic kidney disease is unknown. Here, in mouse models of both obstructive nephropathy and focal segmental glomerulosclerosis (adriamycin nephropathy), we observed upregulation of MMP-7 mRNA and protein in a time-dependent manner. The pattern and extent of MMP-7 induction were positively associated with Wnt/ß-catenin signaling in these models. Activation of ß-catenin through ectopic expression of Wnt1 promoted MMP-7 expression in vivo, whereas delivery of the gene encoding the endogenous Wnt antagonist Dickkopf-1 abolished its induction. Levels of MMP-7 protein detected in the urine correlated with renal Wnt/ß-catenin activity. Pharmacologic blockade of Wnt/ß-catenin signaling by paricalcitol inhibited MMP-7 expression in diseased kidneys and reduced the levels detected in the urine. In vitro, ß-catenin activation induced the expression and secretion of MMP-7 and promoted the binding of T cell factor to the MMP-7 promoter in kidney epithelial cells. We also observed higher levels of MMP-7 expression, which correlated with ß-catenin, in kidney tissue from patients with various nephropathies. In summary, levels of renal MMP-7 correlate with Wnt/ß-catenin activity, and urinary MMP-7 may be a noninvasive biomarker of this profibrotic signaling in the kidney.

Quality Similarity between Induced Agarwood by Fungus and Wild Agarwood.

To prevent the exploitation of wild agarwood, the development of artificial agarwood through fungal inoculation is a promising method, but finding species that produce efficient high-quality agarwood remains difficult. In this study, a fungal inducer was prepared using wild agarwood containing fungi and high-throughput sequencing was performed to determine its species makeup. Subsequently, it was used to inoculate Aquilaria sinensis(Lour.) Spreng. The induced agarwood (IA), wild agarwood (WA), and nonresinous whitewood (WW) were analyzed for the extract content. In addition, liquid and gas chromatography-mass spectrometry was used to determine the chemical composition of the samples. The results were used to evaluate the quality of the IA. Mortierella humilisLinnem. ex W.Gams, Oidiodendron maius(Barron), and Tolypocladium album(W. Gams) Quandt, Kepler, and Spatafora were the fungal inducers that were discovered to produce agarwood. The extracts from the IA and WA contained 64 and 69 2-(2-phenylethyl)chromones, respectively, while there were none in the WW. Furthermore, 20 (relative content 36.19%) and 27 (relative content 54.92%) sesquiterpenes were identified in the essential oils of the IA and WA, respectively, and none were identified in the WW. The fungal inducer that was prepared from the WA effectively improves the quality of the agarwood, which is extremely similar to that of the WA.