Single-stranded RNAs use RNAi to potently and allele-selectively inhibit mutant huntingtin expression.

Mutant huntingtin (HTT) protein causes Huntington disease (HD), an incurable neurological disorder. Silencing mutant HTT using nucleic acids would eliminate the root cause of HD. Developing nucleic acid drugs is challenging, and an ideal clinical approach to gene silencing would combine the simplicity of single-stranded antisense oligonucleotides with the efficiency of RNAi. Here, we describe RNAi by single-stranded siRNAs (ss-siRNAs). ss-siRNAs are potent (>100-fold more than unmodified RNA) and allele-selective (>30-fold) inhibitors of mutant HTT expression in cells derived from HD patients. Strategic placement of mismatched bases mimics micro-RNA recognition and optimizes discrimination between mutant and wild-type alleles. ss-siRNAs require Argonaute protein and function through the RNAi pathway. Intraventricular infusion of ss-siRNA produced selective silencing of the mutant HTT allele throughout the brain in a mouse HD model. These data demonstrate that chemically modified ss-siRNAs function through the RNAi pathway and provide allele-selective compounds for clinical development.

A Novel Peptide Derived from Arca inflata Induces Apoptosis in Colorectal Cancer Cells through Mitochondria and the p38 MAPK Pathway.

Colorectal carcinoma (CRC) is one of the major causes of cancer-related incidence and deaths. Here, we identified a novel antitumor peptide, P6, with a molecular weight of 2794.8 Da from a marine Chinese medicine, Arca inflata Reeve. The full amino acid sequence and secondary structure of P6 were determined by tandem mass de novo sequencing and circular dichroism spectroscopy, respectively. P6 markedly inhibited cell proliferation and colony formation, and induced apoptosis in CRC cells. Mechanistically, transcriptomics analysis and a serial functional evaluation showed that P6 induced colon cancer cell apoptosis through the activation of the p38-MAPK signaling pathway. Moreover, it was demonstrated that P6 exhibited antitumor effects in a tumor xenograft model, and induced cell cycle arrest in CRC cells in a concentration-dependent mode. These findings provide the first line of indication that P6 could be a potential therapeutic agent for CRC treatment.

High sensitivity Troponin-T for prediction of adverse events in patients with COVID-19.

BACKGROUND: High sensitivity cardiac troponin-T (hs-TnT) has been associated with mortality in patients hospitalized with COVID-19. We aimed to determine if hs-TnT levels and their timing are independent predictors of adverse events in these patients. DESIGN: Retrospective chart review was performed for all patients hospitalized at our institution between 23 March 2020 and 13 April 2020 who were found to be COVID-19-positive. Clinical, demographic, and laboratory variables including initial and peak hs-TnT were recorded. Univariable and multivariable analyses were completed for a primary composite endpoint of in-hospital death, intubation, need for critical care, or cardiac arrest. RESULTS: In the 276 patients analysed, initial hs-TnT above the median (≥17 ng/L) was associated with increased length of stay, need for vasoactive medications, and death, along with the composite endpoint (OR 3.92, p < 0.001). Multivariable analysis demonstrated that elevated initial hs-TnT was independently associated with the primary endpoint (OR 2.92, p = 0.01). Late-peaking hs-TnT (OR 2.19 for each additional day until peak, p < 0.001) was also independently associated with the composite endpoint. CONCLUSIONS: In patients hospitalized with COVID-19, hs-TnT identifies patients at high risk for adverse in-hospital events, and trends of hs-TnT over time, particularly during the first day, provide additional prognostic information.

High-Precision Plane Detection Method for Rock-Mass Point Clouds Based on Supervoxel.

In respect of rock-mass engineering, the detection of planar structures from the rock-mass point clouds plays a crucial role in the construction of a lightweight numerical model, while the establishment of high-quality models relies on the accurate results of surface analysis. However, the existing techniques are barely capable to segment the rock mass thoroughly, which is attributed to the cluttered and unpredictable surface structures of the rock mass. This paper proposes a high-precision plane detection approach for 3D rock-mass point clouds, which is effective in dealing with the complex surface structures, thus achieving a high level of detail in detection. Firstly, the input point cloud is fast segmented to voxels using spatial grids, while the local coplanarity test and the edge information calculation are performed to extract the major segments of planes. Secondly, to preserve as much detail as possible, supervoxel segmentation instead of traditional region growing is conducted to deal with scattered points. Finally, a patch-based region growing strategy applicable to rock mass is developed, while the completed planes are obtained by merging supervoxel patches. In this paper, an artificial icosahedron point cloud and four rock-mass point clouds are applied to validate the performance of the proposed method. As indicated by the experimental results, the proposed method can make high-precision plane detection achievable for rock-mass point clouds while ensuring high recall rate. Furthermore, the results of both qualitative and quantitative analyses evidence the superior performance of our algorithm.

Morphological and structural evolution of WS2 nanosheets irradiated with an electron beam.

The morphological and structural evolution of WS2 nanosheets under electron irradiation is investigated using high-resolution transmission electron microscopy. During irradiation, the sulfur atoms that interacted with the electrons were sputtered first and the tungsten atoms began to sputter when the surrounding sulfur atoms had been sputtered. With an increasing irradiation time, the remaining tungsten atoms rearranged to form new structures. In addition, the damage to the WS2 nanosheets became more severe with increasing electron energies and irradiation times.

ss-siRNAs allele selectively inhibit ataxin-3 expression: multiple mechanisms for an alternative gene silencing strategy.

Single-stranded silencing RNAs (ss-siRNAs) provide an alternative approach to gene silencing. ss-siRNAs combine the simplicity and favorable biodistribution of antisense oligonucleotides with robust silencing through RNA interference (RNAi). Previous studies reported potent and allele-selective inhibition of human huntingtin expression by ss-siRNAs that target the expanded CAG repeats within the mutant allele. Mutant ataxin-3, the genetic cause of Machado-Joseph Disease, also contains an expanded CAG repeat. We demonstrate here that ss-siRNAs are allele-selective inhibitors of ataxin-3 expression and then redesign ss-siRNAs to optimize their selectivity. We find that both RNAi-related and non-RNAi-related mechanisms affect gene expression by either blocking translation or affecting alternative splicing. These results have four broad implications: (i) ss-siRNAs will not always behave similarly to analogous RNA duplexes; (ii) the sequences surrounding CAG repeats affect allele-selectivity of anti-CAG oligonucleotides; (iii) ss-siRNAs can function through multiple mechanisms and; and (iv) it is possible to use chemical modification to optimize ss-siRNA properties and improve their potential for drug discovery.

Mechanism of allele-selective inhibition of huntingtin expression by duplex RNAs that target CAG repeats: function through the RNAi pathway.

Huntington's disease is an incurable neurodegenerative disorder caused by expansion of a CAG trinucleotide repeat within one allele of the huntingtin (HTT) gene. Agents that block expression of mutant HTT and preserve expression of wild-type HTT target the cause of the disease and are an alternative for therapy. We have previously demonstrated that mismatch-containing duplex RNAs complementary to the expanded trinucleotide repeat are potent and allele-selective inhibitors of mutant HTT expression, but the mechanism of allele selectivity was not explored. We now report that anti-CAG duplex RNA preferentially recruits argonaute 2 (AGO2) to mutant rather than wild-type HTT mRNA. Efficient inhibition of mutant HTT protein expression requires less AGO2 than needed for inhibiting wild-type expression. In contrast, inhibiting the expression of mutant HTT protein is highly sensitive to reduced expression of GW182 (TNRC6A) and its two paralogs, a protein family associated with miRNA action. Allele-selective inhibition may involve cooperative binding of multiple protein-RNA complexes to the expanded repeat. These data suggest that allele-selective inhibition proceeds through an RNA interference pathway similar to that used by miRNAs and that discrimination between mutant and wild-type alleles of HTT mRNA is highly sensitive to the pool of AGO2 and GW182 family proteins inside cells.

RRP15 deficiency induces ribosome stress to inhibit colorectal cancer proliferation and metastasis via LZTS2-mediated ß-catenin suppression.

Ribosome biogenesis (RiBi) plays a pivotal role in carcinogenesis by regulating protein translation and stress response. Here, we find that RRP15, a nucleolar protein critical for RiBi and checkpoint control, is frequently upregulated in primary CRCs and higher RRP15 expression positively correlated with TNM stage (P < 0.0001) and poor survival of CRC patients (P = 0.0011). Functionally, silencing RRP15 induces ribosome stress, cell cycle arrest, and apoptosis, resulting in suppression of cell proliferation and metastasis. Overexpression of RRP15 promotes cell proliferation and metastasis. Mechanistically, ribosome stress induced by RRP15 deficiency facilitates translation of TOP mRNA LZTS2 (Leucine zipper tumor suppressor 2), leading to the nuclear export and degradation of ß-catenin to suppress Wnt/ß-catenin signaling in CRC. In conclusion, ribosome stress induced by RRP15 deficiency inhibits CRC cell proliferation and metastasis via suppressing the Wnt/ß-catenin pathway, suggesting a potential new target in high-RiBi CRC patients.

Effect of chemical modifications on modulation of gene expression by duplex antigene RNAs that are complementary to non-coding transcripts at gene promoters.

Antigene RNAs (agRNAs) are small RNA duplexes that target non-coding transcripts rather than mRNA and specifically suppress or activate gene expression in a sequence-dependent manner. For many applications in vivo, it is likely that agRNAs will require chemical modification. We have synthesized agRNAs that contain different classes of chemical modification and have tested their ability to modulate expression of the human progesterone receptor gene. We find that both silencing and activating agRNAs can retain activity after modification. Both guide and passenger strands can be modified and functional agRNAs can contain 2'F-RNA, 2'OMe-RNA, and locked nucleic acid substitutions, or combinations of multiple modifications. The mechanism of agRNA activity appears to be maintained after chemical modification: both native and modified agRNAs modulate recruitment of RNA polymerase II, have the same effect on promoter-derived antisense transcripts, and must be double-stranded. These data demonstrate that agRNA activity is compatible with a wide range of chemical modifications and may facilitate in vivo applications.

Emerging views of statin pleiotropy and cholesterol lowering.

Over the past four decades, no class of drugs has had more impact on cardiovascular health than the 3-hydroxy-methylglutaryl coenzyme A reductase inhibitors or statins. Developed as potent lipid-lowering agents, statins were later shown to reduce morbidity and mortality of patients who are at risk for cardiovascular disease. However, retrospective analyses of some of these clinical trials have uncovered some aspects of their clinical benefits that may be additional to their lipid-lowering effects. Such 'pleiotropic' effects of statins garnered intense interest and debate over its contribution to cardiovascular risk reduction. This review will provide a brief background of statin pleiotropy, assess the available clinical evidence for and against their non-lipid-lowering benefits, and propose future research directions in this field.

Electron coupled FeS2/MoS2 heterostructure for efficient electrocatalytic ammonia synthesis under ambient conditions.

Developing efficient ammonia synthesis technology under ambient conditions is of vital importance. In this work, an FeS2 coupled MoS2 heterostructure with ultrathin features was designed by a one-step hydrothermal process for the electrochemical nitrogen reduction reaction. Density functional theory calculations reveal that the electronic structure of MoS2 greatly changes with the introduction of FeS2. The modulated electronic structure of MoS2 not only exhibits enhanced conductivity but also facilitates the activation of N2 molecules due to its abundant electronic region. The optimized FeS2/MoS2 nanosheet heterostructure achieves a high NH3 yield rate of 2.59 µmol h-1 mg-1 and a FE of 4.63% at -0.3 V vs. RHE. Besides, the well-designed nanocomposite also shows excellent selectivity without N2H4 by-products and exhibits good stability after electrocatalysis for 48 hours.

High-yielding preparation of hierarchically branched carbon nanotubes derived from zeolitic imidazolate frameworks for enhanced electrochemical K+ storage.

Branched carbon nanotubes are regarded as very promising anode materials of K-ion batteries, while the high-yielding preparation still remains challenging. We here demonstrate a facile approach for synthesizing N-doped branched carbon nanotubes (br-CNTs) in macroscopic quantity, via one-step carbonization of ZnCo-containing zeolitic imidazolate framework (ZnCo-ZIF) nanotubes. At a high current density of 2 A g-1, the as-synthesized br-CNTs could exhibit 147.2 mA h g-1 specific capacity and retain 84.5% of the initial value after 1300 cycles for electrochemical K+ storage, which is better than commercial carbon nanotubes and other carbon counterparts derived from ZnCo-ZIF particles and ZnCo-BTC nanowires. The excellent K+ storage performance of ZnCo-ZIF-derived br-CNTs actually results from the unique branched architecture and N doping, by taking advantage of more active sites and desired electrochemical kinetics as well as structural integrity. Our proposed approach would give a significant example for the scalable preparation of other complex nanostructures, and the prepared br-CNT is expected to be a very competitive candidate for high-efficiency electrochemical K+ storage.

Clonal Rett Syndrome cell lines to test compounds for activation of wild-type MeCP2 expression.

Rett Syndrome is an X-linked progressive neurological disorder caused by inactivation of one allele of the MECP2 gene. There are no curative treatments, and activation of wild-type MECP2 expression is one strategy for stabilizing or reversing the disease. We isolated fibroblast clones that express exclusively either the wild-type or a 32-bp-deletion mutant form of MECP2. We developed a sensitive assay for measuring wild-type MECP2 mRNA levels and tested small molecule epigenetic activators for their ability to activate gene expression. Although our pilot screen did not identify activators of MECP2 expression, it established the value of using clonal cells and defined challenges that must be overcome.

A solvent-assisted ligand exchange approach enables metal-organic frameworks with diverse and complex architectures.

Unlike inorganic crystals, metal-organic frameworks do not have a well-developed nanostructure library, and establishing their appropriately diverse and complex architectures remains a major challenge. Here, we demonstrate a general route to control metal-organic framework structure by a solvent-assisted ligand exchange approach. Thirteen different types of metal-organic framework structures have been prepared successfully. To demonstrate a proof of concept application, we used the obtained metal-organic framework materials as precursors for synthesizing nanoporous carbons and investigated their electrochemical Na+ storage properties. Due to the unique architecture, the one-dimensional nanoporous carbon derived from double-shelled ZnCo bimetallic zeolitic imidazolate framework nanotubes exhibits high specific capacity as well as superior rate capability and cycling stability. Our study offers an avenue for the controllable preparation of well-designed meta-organic framework structures and their derivatives, which would further broaden the application opportunities of metal-organic framework materials.

Highly Cation Permselective Metal-Organic Framework Membranes with Leaf-Like Morphology.

Highly cation permselective metal-organic framework (MOF) membranes are desirable for the extraction of valuable metal cations. However, fabrication of defect-free and stable permselective MOF membranes is technically challenging, owing to their arduous self-assembly and poor water resistance, respectively. A simple and readily scalable method has been developed for the controlled in situ smart growth of UiO-66-NH2 into leaf-like nanostructures with tunable density of the leaves and the surface layer thickness. The self-assembly approach reproducibly fabricates seamless, ultrathin (<500 nm) UiO-66-NH2 membranes at the surface of anodic aluminum oxide. The membranes contain nanosized interstices among the MOF leaves, which enable maximum admission of ions within the membrane, and angstrom-sized inherent pores in every single UiO-66-NH2 crystal, which efficiently regulate the cation permselectivity. Consequently, the highest ever reported cation separations (Na+ /Mg2+ >200 and Li+ /Mg2+ >60) and excellent membrane stability during five sequential electrodialysis cycles are achieved. These characteristics position the fabricated MOF membranes as potential candidates for efficient extraction of pure lithium and sodium ions from salt lakes and seawater, respectively.

[Macrophage phagocytosis enhanced by Tiaohengfang polysaccharides in vitro].

OBJECTIVE: To study the immunoregulatory effect of Tiaohengfang polysaccharides (THFPS) on the phagocytosis of macrophages. METHODS: According to the preparing method of Chinese medicine polysaccharides, crude polysaccharides were extracted from Tiaohengfang. Mouse peritoneal macrophages were separated and cultured. After the macrophages were treated with (500, 200, 10) µg/mL THFPS for 48 hours, the cell morphology was observed under a light microscope. Phagocytic tests of ink and Staphylococcus aureus were used to evaluate the phagocytosis of the macrophages, and cell enzyme chemical staining was applied to observe the changes of acid phosphatase in macrophages. RESULTS: Compared with the control group, the volume of macrophages significantly became bigger when they were treated with (500, 200, 10) µg/mL THFPS, the intake of ink and Staphylococcus aureus significantly increased, and the activity of acid phosphatase was also significantly enhanced, which was positively correlated with the dose of THFPS. CONCLUSION: THFPS can enhance the phagocytosis of macrophages and increase the activity of intracellular acid phosphatase.

Exploring the effect of sequence length and composition on allele-selective inhibition of human huntingtin expression by single-stranded silencing RNAs.

Mutant huntingtin (HTT) protein is the cause of Huntington's disease (HD), an incurable neurological disorder. Almost all patients are heterozygous for mutant HTT and approaches that reduce levels of mutant HTT while leaving expression of wild-type HTT intact might be ideal options for therapeutic development. We have developed several allele-selective strategies for silencing HTT, including single-stranded silencing RNAs (ss-siRNAs). ss-siRNAs are oligonucleotides containing chemical modifications that permit action through the RNA interference (RNAi) pathway. Modified ss-siRNAs chosen to test the effects of varying oligomer length, lipid modification, the introduction of mismatched bases, and variation of chemical modification. We find that several modified ss-siRNA are potent and allele-selective inhibitors of HTT expression. An ss-siRNA with three mismatched bases relative to the CAG repeat was an allele-selective inhibitor of HTT expression in the HdhQ175 mouse model. Multiple allele-selective ss-siRNAs provide a wide platform of modifications to draw on for further optimization and therapeutic development. Our data provide insights into how ss-siRNAs can be modified to improve their properties and facilitate the discovery of the lead compounds necessary for further development.