Lignans from the Roots and Rhizomes of Dysosma versipellis and Their Cytotoxic Activities.

One new dibenzyltyrolactone lignan dysoslignan A (1), three new arylnaphthalide lignans dysoslignan B-C (2-4), along with fourteen known metabolites (5-18), were isolated from the roots and rhizomes of Dysosma versipellis. Their structures and stereochemistry were determined from analysis of NMR spectroscopic and circular dichroism (CD) data. Compound 2 represents the first report of naturally occurring arylnaphthalide lignan triglycoside. The cytotoxic activities of all isolated compounds were evaluated against A-549 and SMMC-7721 cell lines. Compounds 7-10 and 14-16 were more toxic than cisplatin in two tumor cell lines. This investigation clarifies the potential effective substance basis of D. versipellis in tumor treatment.

Dysosmaflavonoid A-F, new flavonols with potent DPPH radical scavenging activity from Dysosma versipellis.

Six new flavonols, including four glucosylated flavonols (dysosmaflavonoid A-D), one phenylpropanoid-substituted flavonol (dysosmaflavonoid E), and one phenyl-substituted flavonol (dysosmaflavonoid F), together with five known analogues, were isolated from the roots and rhizomes of Dysosma versipellis. Their structures were elucidated by comprehensive analysis of their NMR, IR, UV, HRESIMS, and HPLC data. The antioxidant activities of all isolated compounds were examined by 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay. Compounds 2, 3, 5-8, and 12 exhibited significant DPPH scavenging capacity with IC50 values of 33.95, 39.02, 31.17, 32.79, 31.85, 30.48, and 23.75 µM, respectively, in comparison with Trolox (IC50, 15.80 µM). Compound 12 displayed more potent DPPH radical scavenging activity than prenylated and (or) glucosided derivatives (2-4, or 10). The preliminary structure-activity relationship showed that the catechol structure in flavonol is essential for DPPH radical scavenging effect.

Structurally diverse biflavonoids from Dysosma versipellis and their bioactivity.

Five pairs of new biflavonoid enantiomers, (±)-dysosmabiflavonoids A-E (1-5), two new biflavonoids, dysosmabiflavonoids F-G (6-7), and four biosynthetically related precursors (8-11) were isolated from the roots and rhizomes of Dysosma versipellis. Their structures were elucidated by extensive spectroscopic analysis, including HR-ESI-MS and 2D NMR. Their absolute configurations were determined by comparison of the calculated and experimental ECD spectra. All isolated compounds were evaluated for AChE inhibitory activity. Compounds 6 and 7 exhibited more potent inhibitory activities with IC50 values of 1.42 and 0.73 µM, respectively, than their biosynthetically related precursors kaempferol (8, 17.90 µM) and quercetin (9, 3.96 µM). The preliminary structure-activity relationship study indicated that the connection mode of biflavonoid subunits, oxidation degree of the C ring, and 3,4-dihydroxy group of the B ring were important structural factors for AChE inhibitory activity. Racemates 1-5 and their corresponding levorotatory and dextrorotatory enantiomers were tested for their potential to impede the generation of NO in lipopolysaccharide-stimulated RAW264.7 cells, and their mushroom tyrosinase inhibitory effect. Racemate 1 displayed more potent mushroom tyrosinase inhibitory activity (IC50, 28.27 µM) than the positive control kojic acid (IC50, 32.59 µM). D. versipellis may have therapeutic potential for melanogenesis disorders and neurodegenerative diseases.

Identification and analysis of DNA methylation-driven signatures for prognostic and immune microenvironments evaluation in hepatocellular carcinoma.

Liver cancer is the main reason of cancer deaths globally, with an unfavorable prognosis. DNA methylation is one of the epigenetic modifications and maintains the right adjustment of gene expression and steady gene silencing. We aim to explore the novel signatures for prognosis by using DNA methylation-driven genes. To acquire the DNA methylation-driven genes, we perform the difference analysis from the gene expression data and DNA methylation data in TCGA or GEO databases. And we obtain the 31 DNA methylation-driven genes. Subsequently, consensus clustering analysis was utilized to identify the molecular subtypes based on the 31 DNA methylation-driven genes. So, two molecular subtypes were identified to perform those analyses: Survival, immune cell infiltration, and tumor mutation. Results showed that two subtypes were clustered with distinct prognoses, tumor-infiltrating immune cell and tumor mutation burden. Furthermore, the 31 DNA methylation-driven genes were applied to perform the survival analysis to select the 14 survival-related genes. Immediately, a five methylation-driven genes risk model was built, and the patients were divided into high and low-risk groups. The model was established with TCGA as the training cohort and GSE14520 as the validation cohort. According to the risk model, we perform the systematical analysis, including survival, clinical feature, immune cell infiltration, somatic mutation status, underlying mechanisms, and drug sensitivity. Results showed that the high and low groups possessed statistical significance. In addition, the ROC curve was utilized to measure the accuracy of the risk model. AUCs at 1-year, 3-years, and 5-years were respectively 0.770, 0.698, 0.676 in training cohort and 0.717, 0.649, 0.621 in validation cohort. Nomogram was used to provide a better prediction for patients' survival. Risk score increase the accuracy of survival prediction in HCC patients. In conclusion, this study developed a novel risk model of five methylation-driven genes based on the comprehensive bioinformatics analysis, which accurately predicts the survival of HCC patients and reflects the immune and mutation features of HCC. This study provides novel insights for immunotherapy of HCC patients and promotes medical progress.

Polar Species for Effective Dielectric Regulation to Achieve High-Performance CsPbI3 Solar Cells.

Nonradiative losses caused by defects are the main obstacles to further advancing the efficiency and stability of perovskite solar cells (PSCs). There is focused research to boost the device performance by reducing the number of defects and deactivating defects; however, little attention is paid to the defect-capture capacity. Here, upon systematically examining the defect-capture capacity, highly polarized fluorinated species are designed to modulate the dielectric properties of the perovskite material to minimize its defect-capture radius. On the one hand, fluorinated polar species strengthen the defect dielectric-screening effect via enhancing the dielectric constant of the perovskite film, thus reducing the defect-capture radius. On the other, the fluorinated iodized salt replenishes the I-vacancy defects at the surface, hence lowering the defect density. Consequently, the power-conversion efficiency of an all-inorganic CsPbI3 PSC is increased to as high as 20.5% with an open-circuit voltage of 1.2 V and a fill factor of 82.87%, all of which are among the highest in their respective categories. Furthermore, the fluorinated species modification also produces a hydrophobic umbrella yielding significantly improved humidity tolerance, and hence long-term stability. The present strategy provides a general approach to effectually regulate the defect-capture radius, thus enhancing the optoelectronic performance.

Cytotoxic Polyhydroxylated Oleanane Triterpenoids from Cissampelos pareira var. hirsuta.

Three new polyhydroxylated oleanane triterpenoids, cissatriterpenoid A-C (1-3), along with one known analogue (4), were isolated from the whole plant of Cissampelos pareira var. hirsuta. Their chemical structures were elucidated by extensive spectroscopic data (IR, HR-ESI-MS, 1H-NMR, 13C-NMR, DEPT, 1H-1H COSY, HSQC, HMBC, NOESY) and the microhydrolysis method. The isolation of compounds 1-4 represents the first report of polyhydroxylated oleanane triterpenoids from the family Menispermaceae. All isolated compounds were evaluated for their cytotoxicity against five human cancer cell lines, and the inhibitory activity against NO release in LPS-induced RAW 264.7 cells. Compound 3 showed the most potent cytotoxic activities against the A549, SMMC-7721, MCF-7, and SW480 cell lines, with IC50 values of 17.55, 34.74, 19.77, and 30.39 µM, respectively, whereas three remaining ones were found to be inactive. The preliminary structure-activity relationship analysis indicated that the γ-lactone ring at C-22 and C-29, and the olefinic bond at C-12 and C-13 were structurally required for the cytotoxicity of polyhydroxylated oleanane triterpenoids against these four cell lines. Based on lipid-water partition coefficients, compound 3 is less lipophilic than 1 and 4, which agrees with their cytotoxic activities. This confirms the potential of C. pareira var. hirsuta in the tumor treatment.

Molten-Salt-Assisted CsPbI3 Perovskite Crystallization for Nearly 20%-Efficiency Solar Cells.

Dynamic manipulation of crystallization is pivotal to the quality of polycrystalline films. A molten-salt-assisted crystallization (MSAC) strategy is presented to improve grain growth of the all-inorganic perovskite films. Compared with the traditional solvent annealing, MSAC enables more intensive mass transfer by means of convection and diffusion, which is beneficial to the interaction among the precursor colloids and to inducing in-plane growth of perovskite grains, resulting in the formation of high-quality perovskite films with suppressed pinhole and crack formation. Additionally, the introduction of molten salt alters the intermediate phases, and thus changes the crystallization pathways by reducing the energy barrier to produce films with desired optical and electrical properties. As a result, the MSAC strategy endows the devices with champion steady-state output efficiency of 19.83% and open-circuit voltage (Voc ) as high as 1.2 V, among the highest for this type of solar cell, thanks to its effectively reduced Voc deficit.

Structural basis of target DNA recognition by CRISPR-Cas12k for RNA-guided DNA transposition.

The type V-K CRISPR-Cas system, featured by Cas12k effector with a naturally inactivated RuvC domain and associated with Tn7-like transposon for RNA-guided DNA transposition, is a promising tool for precise DNA insertion. To reveal the mechanism underlying target DNA recognition, we determined a cryoelectron microscopy (cryo-EM) structure of Cas12k from cyanobacteria Scytonema hofmanni in complex with a single guide RNA (sgRNA) and a double-stranded target DNA. Coupled with mutagenesis and in vitro DNA transposition assay, our results revealed mechanisms for the recognition of the GGTT protospacer adjacent motif (PAM) sequence and the structural elements of Cas12k critical for RNA-guided DNA transposition. These structural and mechanistic insights should aid in the development of type V-K CRISPR-transposon systems as tools for genome editing.

Structural basis for substrate recognition and cleavage by the dimerization-dependent CRISPR-Cas12f nuclease.

Cas12f, also known as Cas14, is an exceptionally small type V-F CRISPR-Cas nuclease that is roughly half the size of comparable nucleases of this type. To reveal the mechanisms underlying substrate recognition and cleavage, we determined the cryo-EM structures of the Cas12f-sgRNA-target DNA and Cas12f-sgRNA complexes at 3.1 and 3.9 Å, respectively. An asymmetric Cas12f dimer is bound to one sgRNA for recognition and cleavage of dsDNA substrate with a T-rich PAM sequence. Despite its dimerization, Cas12f adopts a conserved activation mechanism among the type V nucleases which requires coordinated conformational changes induced by the formation of the crRNA-target DNA heteroduplex, including the close-to-open transition in the lid motif of the RuvC domain. Only one RuvC domain in the Cas12f dimer is activated by substrate recognition, and the substrate bound to the activated RuvC domain is captured in the structure. Structure-assisted truncated sgRNA, which is less than half the length of the original sgRNA, is still active for target DNA cleavage. Our results expand our understanding of the diverse type V CRISPR-Cas nucleases and facilitate potential genome editing applications using the miniature Cas12f.

Cryo-EM structure of the RNA-guided ribonuclease Cas12g.

Cas12g, the type V-G CRISPR-Cas effector, is an RNA-guided ribonuclease that targets single-stranded RNA substrate. The CRISPR-Cas12g system offers a potential platform for transcriptome engineering and diagnostic applications. We determined the structures of Cas12g-guide RNA complexes in the absence and presence of target RNA by cryo-EM to a resolution of 3.1 Å and 4.8 Å, respectively. Cas12g adopts a bilobed structure with miniature REC2 and Nuc domains, whereas the guide RNAs fold into a flipped 'F' shape, which is primarily recognized by the REC lobe. Target RNA and the CRISPR RNA (crRNA) guide form a duplex that inserts into the central cavity between the REC and NUC lobes, inducing conformational changes in both lobes to activate Cas12g. The structural insights would facilitate the development of Cas12g-based applications.

Cytotoxic polyhydroxylated pregnane glycosides from Cissampelos pareira var. hirsuta.

Fourteen new polyhydroxylated pregnane glycosides, cissasteroid A-N (1-14), and five known analogues (15-19), were isolated from the dried whole plant of Cissampelos pareira var. hirsuta. Their structures and stereochemistry were elucidated by extensive spectroscopic data, chemical hydrolysis, and ECD measurements. All the compounds were tested for their cytotoxicity against five human cancer cell lines, and inhibitory activity against NO release in LPS-induced RAW 264.7 cells. Compared with cisplatin, compound 7 showed more potent cytotoxicities against the HL-60, A549, SMMC-7721, MCF-7, and SW480 cell lines, with IC50 values of 2.19, 14.38, 2.00, 7.58, and 7.44 µM, respectively. The preliminary study of structure-activity relationship indicated that benzoic acid esterification at C-20 may have a negative effect on the cytotoxic activity of polyhydroxylated pregnane derivatives in these five human cancer cell lines. These results revealed the potential of compound 7 as an ideal antitumor lead compound.

Sixteen New Prenylated Flavonoids from the Fruit of Sinopodophyllum hexandrum.

Sixteen new prenylated flavonoids, sinoflavonoids P-Z (1-11) and sinoflavonoids NA-NE (12-16), were isolated from the fruit of Sinopodophyllum hexandrum, along with eight known analogues (17-24). Their structures were elucidated on the basis of extensive spectroscopic data (HR-ESI-MS, 1H-NMR, 13C-NMR, HSQC, HMBC). The cytotoxic activities of compounds 1-18, 20, and 22 were evaluated by MTT assay. Compound 6 showed the most potent cytotoxicity in MCF-7, and HepG2 cell lines, with IC50 values of 6.25 and 3.83 µM, respectively.

Six New Coumarin Glycosides from the Aerial Parts of Gendarussa vulgaris.

Six new coumarin glycosides, genglycoside A-F (1-6), were isolated from the aerial parts of Gendarussa vulgaris, along with ten known analogues (7-16). Their structures were unambiguously established on the basis of extensive spectroscopic data and HPLC analysis. The cytotoxic activities of all isolated compounds were evaluated by MTT assay. Compound 12 showed the most potent cytotoxicity in Eca-109, MCF-7, and HepG2 cell lines. By the preliminary structure-activity relationships, it was firstly discovered that the glycosylation or esterification at 7,8-dihydroxy or 7-hydroxy drastically reduced the cytotoxic activity of the parent coumarin.

Expression, purification, and evaluation of in vivo anti-fibrotic activity for soluble truncated TGF-ß receptor II as a cleavable His-SUMO fusion protein.

Excessive production of transforming growth factor-ß1 (TGF-ß1) and its binding to transforming growth factor-ß receptor type II (TGF-ßRII) promotes fibrosis by activation of the TGF-ß1-mediated signaling pathway. Thus, the truncated extracellular domain of TGF-ßRII (tTßRII) is a promising anti-fibrotic candidate, as it lacks the signal transduction domain. In this work, the native N-terminal tTßRII was prepared as a His-SUMO fusion protein (termed His-SUMO-tTßRII) in Escherichia coli strain BL21 (DE3). His-SUMO-tTßRII was expressed as a soluble protein under optimal conditions (6 h of induction with 0.5 mM IPTG at 37 °C). His-SUMO-tTßRII was purified by Ni-NTA resin chromatography, and then cleaved with SUMO protease to release native tTßRII, which was re-purified using a Ni-NTA column. Approximately 12 mg of native tTßRII was obtained from a one liter fermentation culture with no less than 95% purity. In vivo studies demonstrated that tTßRII prevented CCl4-induced liver fibrosis, as evidenced by the inhibition of fibrosis-related Col I and α-SMA protein expression in C57BL/6 mice. In addition, tTßRII downregulated phosphorylation of SMAD2/3, which partly repressed TGF-ß1-mediated signaling. These data indicate that the His-SUMO expression system is an efficient approach for preparing native tTßRII that possesses anti-liver fibrotic activity, allowing for the large-scale production of tTßRII, which potentially could serve as an anti-fibrotic candidate for treatment of TGF-ß1-related diseases.

Isolation and molecular cloning of hepatocyte growth factor from guinea pig (gHGF), and expression of truncated variant of gHGF with improved anti-fibrotic activity in Escherichia coli.

Hepatocyte growth factor (HGF) is an attractive target for anti-fibrotic therapy because it attenuates excessive transforming growth factor-ß1 (TGF-ß1) which plays an important role in hepatic fibrosis. In the study, we reported on the isolation and molecular cloning of the open reading frame (ORF) of guinea pig HGF (gHGF), encoding a protein of 729 amino acids, with an apple-like (hairpin) domain, four kringle domains and a trypsin-like serine protease domain. Moreover, the truncated variant of gHGF (a double mutant of N-terminal hairpin and first kringle domains of gHGF, K132E and G134E, gmNK1) protein fused with His6 tag, the molecular weight of which was about 20.0kDa, which was expressed in Escherichia coli BL21 (DE3) and purified with Ni2+-affinity chromatography. Furthermore, gmNK1 inhibited protein expression levels of fibrosis-related type I collagen (Col I) and α-smooth muscle actin (α-SMA) genes in TGF-ß1-activated HSC-T6 cells and CCl4-induced liver fibrosis in rat. In addition, gmNK1 ameliorated liver morphology and fibrotic responses in fibrosis animal. Taken together, we first reported on the sequence of HGF from guinea pig and determined the anti-fibrotic activity of gmNK1 in hepatic fibrosis, which will be helpful for investigations into the biological roles of gHGF in this important animal model.

Early Predictors of Acute Kidney Injury: A Narrative Review.

Accompanied with the broad application of interventional therapy, the incidence of acute kidney injury (AKI) has been recently increasing in clinical renal medicine. The pathogenesis of AKI is diverse and complex. In the context of the requirements for the diagnosis and treatment of a renal disorder, a large number of studies have explored biological markers and their usefulness to the early diagnosis and treatment of AKI, including glomerular injury, renal tubular injury, and others. These biomarkers provide an important basis for early monitoring of AKI, but are still not quite sufficient. More ideal biomarkers are needed to be identified. Therefore, future studies are necessary to explore more effective biomarkers for AKI clinical practice, which would play an important role in the early diagnosis and intervention treatment of AKI. This review summarizes the important biomarkers identified by previous studies and aims to highlight the advancements that might provide new methods for early clinical diagnosis and effective therapeutic options, along with prediction of response to treatment for AKI.

Magnesium regulates neural stem cell proliferation in the mouse hippocampus by altering mitochondrial function.

In the adult brain, neural stem cells from the subgranular zone (SGZ) of the hippocampus and the subventricular zone (SVZ) of the cortex progress through the following five developmental stages: radial glia-like cells, neural progenitor cells, neuroblasts, immature neurons, and mature neurons. These developmental stages are linked to both neuronal microenvironments and energy metabolism. Neurogenesis is restricted and has been demonstrated to arise from tissue microenvironments. We determined that magnesium, a key nutrient in cellular energy metabolism, affects neural stem cell (NSC) proliferation in cells derived from the embryonic hippocampus by influencing mitochondrial function. Densities of proliferating cells and NSCs both showed their highest values at 0.8 mM [Mg(2+) ]o , whereas lower proliferation rates were observed at 0.4 and 1.4 mM [Mg(2+) ]o . The numbers and sizes of the neurospheres reached the maximum at 0.8 mM [Mg(2+) ]o and were weaker under both low (0.4 mM) and high (1.4 mM) concentrations of magnesium. In vitro experimental evidence demonstrates that extracellular magnesium regulates the number of cultured hippocampal NSCs, affecting both magnesium homeostasis and mitochondrial function. Our findings indicate that the effect of [Mg(2+) ]o on NSC proliferation may lie downstream of alterations in mitochondrial function because mitochondrial membrane potential was highest in the NSCs in the moderate [Mg(2+) ]o (0.8 mM) group and lower in both the low (0.4 mM) and high (1.4 mM) [Mg(2+) ]o groups. Overall, these findings demonstrate a new function for magnesium in the brain in the regulation of hippocampal neural stem cells: affecting their cellular energy metabolism.