New Immunomodulating Polyhydroxypregnane Glycosides from the Roots of Cynanchum otophyllum C.K.Schneid.

Seven new polyhydroxypregnane glycosides, named cynotophyllosides P–V, together with three known analogs were isolated from the roots of Cynanchum otophyllum C.K.Schneid . Their structures were elucidated by a variety of spectroscopic techniques, as well as acid‐catalyzed hydrolysis. All isolates were tested for their immunological activities in vitro against Con A‐ and LPS‐induced proliferation of mice splenocytes. Immunoenhancing (for 1 , 9 ) and immunosuppressive (for 2 ) activities were observed. Furthermore, cynotophylloside R ( 3 ) showed immunomodulatory as it enhanced the proliferation of splenocytes in low concentration and suppressed immune cells in concentration more than 1.0 μg/ml.     

Inverse Optical Cavity Design for Ultrabroadband Light Absorption Beyond the Conventional Limit in Low‐Bandgap Nonfullerene Acceptor–Based Solar Cells

In the subwavelength regime, several nanophotonic configurations have been proposed to overcome the conventional light trapping or light absorption enhancement limit in solar cells also known as the Yablonovitch limit. It has been recently suggested that establishing such limit should rely on computational inverse electromagnetic design instead of the traditional approach combining intuition and a priori known physical effect. In the present work, by applying an inverse full wave vector electromagnetic computational approach, a 1D nanostructured optical cavity with a new resonance configuration is designed that provides an ultrabroadband (≈450 nm) light absorption enhancement when applied to a 107 nm thick active layer organic solar cell based on a low‐bandgap (1.32 eV) nonfullerene acceptor. It is demonstrated computationally and experimentally that the absorption enhancement provided by such a cavity surpasses the conventional limit resulting from an ergodic optical geometry by a 7% average over a 450 nm band and by more than 20% in the NIR. In such a cavity configuration the solar cells exhibit a maximum power conversion efficiency above 14%, corresponding to the highest ever measured for devices based on the specific nonfullerene acceptor used.     

A novel de novo PDE4D gene mutation identified in a Chinese patient with acrodysostosis

Acrodysostosis is an extremely rare disorder at birth, that is, characterized by skeletal dysplasia with short stature and midfacial hypoplasia, which has been reported to be caused by PDE4D and PRKAR1A gene mutations. Here, a Chinese boy with acrodysostosis, ventricular septal defect, and pulmonary hypertension was recruited for our study, and his clinical and biochemical characteristics were analyzed. A novel de novo heterozygous missense mutation (NM_001104631: c.2030A>C, p.Tyr677Ser) of the PDE4D gene was detected by whole exome sequencing and confirmed by Sanger sequencing. The c.2030A>C (p.Tyr677Ser) variant was located in exon 15 of the PDE4D gene, predicted to be damaging by a functional prediction program and shown to be highly conserved among many species. Further functional analysis showed that the p.Tyr677Ser substitution changes the function of the PDE4D protein, affects its subcellular localization in transfected cells, increases PDE4 activity in the regulation of cAMP signaling and affects cell proliferation. Our study identified a novel de novo PDE4D mutation in acrodysostosis of Chinese origin that not only contributes a deeper appreciation of the phenotypic characteristics of patients with PDE4D mutations but also expands the spectrum of PDE4D mutations.     

Galectin-3 exacerbates ox-LDL-mediated endothelial injury by inducing inflammation via integrin β1-RhoA-JNK signaling activation

Oxidized low-density lipoprotein (Ox-LDL)-induced endothelial cell injury plays a crucial role in the pathogenesis of atherosclerosis (AS). Plasma galectin-3 (Gal-3) is elevated inside and drives diverse systemic inflammatory disorders, including cardiovascular diseases. However, the exact role of Gal-3 in ox-LDL-mediated endothelial injury remains unclear. This study explores the effects of Gal-3 on ox-LDL-induced endothelial dysfunction and the underlying molecular mechanisms. In this study, Gal-3, integrin β1, and GTP-RhoA in the blood and plaques of AS patients were examined by ELISA and western blot respectively. Their levels were found to be obviously upregulated compared with non-AS control group. CCK8 assay and flow cytometry analysis showed that Gal-3 significantly decreased cell viability and promoted apoptosis in ox-LDL-treated human umbilical vascular endothelial cells (HUVECs). The upregulation of integrinβ1, GTP-RhoA, p-JNK, p-p65, p-IKKα, and p-IKKβ induced by ox-LDL was further enhanced by treatment with Gal-3. Pretreatment with Gal-3 increased expression of inflammatory factors (interleukin [IL]-6, IL-8, and IL-1β), chemokines(CXCL-1 and CCL-2) and adhesion molecules (VCAM-1 and ICAM-1). Furthermore, the promotional effects of Gal-3 on NF-κB activation and inflammatory factors in ox-LDL-treated HUVECs were reversed by the treatments with integrinβ1-siRNA or the JNK inhibitor. We also found that integrinβ1-siRNA decreased the protein expression of GTP-RhoA and p-JNK, while RhoA inhibitor partially reduced the upregulated expression of p-JNK induced by Gal-3. In conclusion, our finding suggests that Gal-3 exacerbates ox-LDL-mediated endothelial injury by inducing inflammation via integrin β1-RhoA-JNK signaling activation.     

Rice sulfoquinovosyltransferase SQD2.1 mediates flavonoid glycosylation and enhances tolerance to osmotic stress

Sulfoquinovosyltransferase 2 (SQD2) catalyses the final step in the sulfoquinovosyldiacylglycerol (SQDG) biosynthetic pathway. It is involved in the phosphate starvation response. Here, we show that rice SQD2.1 has dual activities catalysing SQDG synthesis and flavonoid glycosylation. SQD2.1 null mutants (sqd2.1) in rice had decreased levels of glycosidic flavonoids, particularly apigenin 7‐O‐glucoside (A7G), whereas these metabolites were increased in rice plants overexpressing SQD2.1. The sqd2.1 mutants and SQD2.1 overexpressing lines showed reduced and enhanced, respectively, tolerance to salinity and drought. Treating the sqd2.1 mutants with A7G decreased oxidative damage and restored stress tolerance to the wild‐type levels. These findings demonstrate that SQD2.1 has a novel function in the glycosylation of flavonoids that is required for osmotic stress tolerance in rice. The novel activity of SQD2.1 in the production of glycosidic flavonoids improves scavenging of reactive oxygen species and protects against excessive oxidation.     

Exosome-mediated miR-7-5p delivery enhances the anticancer effect of Everolimus via blocking MNK/eIF4E axis in non-small cell lung cancer

Everolimus is a kind of mammalian target of rapamycin (mTOR) inhibitors. Activated mitogen-activated protein kinase interacting kinases/eukaryotic translation initiation factor 4E (MNK/eIF4E) axis plays a crucial role in resistance to Everolimus in non-small cell lung cancer (NSCLC). The eIF4E phosphorylation increased by mTOR inhibitors is mainly mediated by MNKs. However, the mechanisms are poorly understood. Recently, extensive reprogramming of miRNA profiles has also been found after long-term mTOR inhibitor exposure. Our previous studies have confirmed that tumor suppressor miR-7-5p is decreased in A549 cells after treatment with Everolimus. Exactly, MNK1 is the target of miR-7-5p. In this study, we investigated the biological functions and potential molecular mechanisms of miR-7-5p in the NSCLC undergoing treatment with Everolimus. We confirmed that Everolimus targeted mTORC1 inducing NSCLC cells to secrete miR-7-5p-loaded exosomes in Rab27A and Rab27B-dependent manners. Loss of intracellular miR-7-5p induced phosphorylation of MNK/eIF4E axis, but a supplement of extra exosomal miR-7-5p could reverse it. Of note, both low expression of miR-7-5p and elevated MNK1 protein were associated with a poor prognosis of NSCLC. Both endogenous miR-7-5p and exo-miR-7-5p enhanced the therapeutic efficacy of Everolimus by inhibiting the proliferation, migration, and metastasis of NSCLC in vitro and in vivo. The combination of miR-7-5p with Everolimus induced apoptosis to exhibit a synergistic anticancer therapeutic efficacy through dual abrogation of MNK/eIF4E and mTOR in NSCLC. In conclusion, Everolimus decreases the intracellular miR-7-5p by releasing of miR-7-5p loaded exosomes from NSCLC cells in Rab27A and Rab27B dependent manners. Either endogenous miR-7-5p or exo-miR-7-5p combined with Everolimus can enhance the anticancer efficacy by targeting MNK/eIF4E axis and mTOR. Besides, both low levels of miR-7-5p and positive expression of MNK1 act as independent poor prognostic biomarkers for NSCLC. Therefore, restoring miR-7-5p carried by exosome may be a promising novel combined therapeutic strategy with Everolimus for NSCLC.Subject terms: Drug development, Growth factor signalling, Oncogenesis     

Cryo-electron microscopy reveals how acetogenins inhibit mitochondrial respiratory complex I

Mitochondrial complex I (NADH:ubiquinone oxidoreductase), a crucial enzyme in energy metabolism, captures the redox potential energy from NADH oxidation/ubiquinone reduction to create the proton motive force used to drive ATP synthesis in oxidative phosphorylation. High-resolution single-particle electron cryo-EM analyses have provided detailed structural knowledge of the catalytic machinery of complex I, but not of the molecular principles of its energy transduction mechanism. Although ubiquinone is considered to bind in a long channel at the interface of the membrane-embedded and hydrophilic domains, with channel residues likely involved in coupling substrate reduction to proton translocation, no structures with the channel fully occupied have yet been described. Here, we report the structure (determined by cryo-EM) of mouse complex I with a tight-binding natural product acetogenin inhibitor, which resembles the native substrate, bound along the full length of the expected ubiquinone-binding channel. Our structure reveals the mode of acetogenin binding and the molecular basis for structure–activity relationships within the acetogenin family. It also shows that acetogenins are such potent inhibitors because they are highly hydrophobic molecules that contain two specific hydrophilic moieties spaced to lock into two hydrophilic regions of the otherwise hydrophobic channel. The central hydrophilic section of the channel does not favor binding of the isoprenoid chain when the native substrate is fully bound but stabilizes the ubiquinone/ubiquinol headgroup as it transits to/from the active site. Therefore, the amphipathic nature of the channel supports both tight binding of the amphipathic inhibitor and rapid exchange of the ubiquinone/ubiquinol substrate and product.     

Detection of Minute Virus of Mice Using Real Time Quantitative PCR in Assessment of Virus Clearance During the Purification Of Mammalian Cell Substrate Derived Biotherapeutics

A real time quantitative PCR assay has been developed for detecting minute virus of mice (MVM). This assay directly quantifies PCR product by monitoring the increase of fluorescence intensity emitted during enzymatic hydrolysis of an oligonucleotide probe labelled covalently with fluorescent reporting and quenching dyes via Taq polymerase 5'-->3' exonuclease activity. The quantity of MVM DNA molecules in the samples was determined using a known amount of MVM standard control DNA fragment cloned into a plasmid (pCR-MVM). We have demonstrated that MVM TaqMan PCR assay is approximately 1000-fold more sensitive than the microplate infectivity assay with the lowest detection limit of approximately one particle per reaction. The reliable detection range is within 100 to 10(9) molecules per reaction with high reproducibility. The intra assay variation is <2.5%, and the inter assays variation is <6.5% when samples contain >100 particles/assay. When we applied the TaqMan PCR to MVM clearance studies done by column chromatography or normal flow viral filtration, we found that the virus removal factors were similar to that of virus infectivity assay. It takes about a day to complete entire assay processes, thus, the TaqMan PCR assay is at least 10-fold faster than the infectivity assay. Therefore, we concluded that this fast, specific, sensitive, and robust assay could replace the infectivity assay for virus clearance evaluation.