MicroRNAs (miRNAs) are a class of noncoding RNAs that regulate target gene expression at the posttranscriptional level. Here, we report that secreted miRNAs can serve as signaling molecules mediating intercellular communication. In human blood cells and cultured THP-1 cells, miR-150 was selectively packaged into microvesicles (MVs) and actively secreted. THP-1-derived MVs can enter and deliver miR-150 into human HMEC-1 cells, and elevated exogenous miR-150 effectively reduced c-Myb expression and enhanced cell migration in HMEC-1 cells. In vivo studies confirmed that intravenous injection of THP-1 MVs significantly increased the level of miR-150 in mouse blood vessels. MVs isolated from the plasma of patients with atherosclerosis contained higher levels of miR-150, and they more effectively promoted HMEC-1 cell migration than MVs from healthy donors. These results demonstrate that cells can secrete miRNAs and deliver them into recipient cells where the exogenous miRNAs can regulate target gene expression and recipient cell function.

Mammalian DNA methylation patterns are established by two de novo DNA methyltransferases, DNMT3A and DNMT3B, which exhibit both redundant and distinctive methylation activities. However, the related molecular basis remains undetermined. Through comprehensive structural, enzymology and cellular characterization of DNMT3A and DNMT3B, we here report a multi-layered substrate-recognition mechanism underpinning their divergent genomic methylation activities. A hydrogen bond in the catalytic loop of DNMT3B causes a lower CpG specificity than DNMT3A, while the interplay of target recognition domain and homodimeric interface fine-tunes the distinct target selection between the two enzymes, with Lysine 777 of DNMT3B acting as a unique sensor of the +1 flanking base. The divergent substrate preference between DNMT3A and DNMT3B provides an explanation for site-specific epigenomic alterations seen in ICF syndrome with DNMT3B mutations. Together, this study reveals distinctive substrate-readout mechanisms of the two DNMT3 enzymes, implicative of their differential roles during development and pathogenesis.

Graphical Abstract Highlights d METTL13 is the physiologic eEF1A lysine 55 dimethyltransferase d METTL13 dimethylation of eEF1A stimulates protein synthesis in cancer cells d The METTL13-eEF1A methylation axis fuels Ras-driven tumorigenesis in vivo d METTL13 depletion sensitizes cancer cells to PI3K and mTOR pathway inhibitors

Hexagonal NiS nanobelts served as novel cathode materials for rechargeable Al-ion batteries based on an AlCl3/[EMIm]Cl ionic liquid electrolyte system. The nano-banded structure of the materials can facilitate the electrolyte immersion and enhance Al(3+) diffusion. The hexagonal NiS nanobelt based cathodes exhibit high storage capacity, good cyclability and low overpotential.

A novel class of hosts suitable for solution processing has been developed based on a conjugated dendritic scaffold. By increasing the dendron generation, the highest occupied molecular orbital (HOMO) energy level can be tuned to facilitate hole injection, while the triplet energy remains at a high level, sufficient to host high-energy-triplet emitters. A power-efficient blue-electrophosphorescent device based on H2 is presented.

Background: Long noncoding RNA (lncRNA) H19 is emerging as a vital regulatory molecule in the progression of different types of cancer and miR-675 is reported to be embedded in H19's first exon. However, their function and specific mechanisms of action have not been fully elucidated. The aim of this study was to identify a novel lncRNA-microRNA-mRNA functional network in gastric cancer. Methods: Quantitative real-time polymerase chain reaction (qRT-PCR) was used to assess the relative expression of H19 and miR-675 in normal (GES-1) and gastric cancer cell lines (SGC-7901, SGC-7901/DDP) as well as in tumor tissues. Gain and loss of function approaches were carried out to investigate the potential roles of H19/miR-675 in cell proliferation and apoptosis. Moreover, Fas associated via death domain (FADD) was validated to be the target of miR-675 via luciferase reporter assay. Western blotting was used to evaluate the protein expression of related signaling pathway. Results: In our study H19 and miR-675 were increased in gastric cancer cell lines and tissues. Overexpression of H19 and miR-675 promoted cell proliferation and inhibited cell apoptosis, whereas knockdown of H19 and miR-675 inhibited these effects. By further examining the underlying mechanism, we showed that H19/miR-675 axis inhibited expression of FADD. FADD downregulation subsequently inhibited the caspase cleavage cascades including caspase 8 and caspase 3. Conclusion: Taken together, our results point to a novel regulatory pathway H19/miR-675/ FADD/caspase 8/caspase 3 in gastric cancer which may be potential target for cancer therapy.

N6-methyladenosine (m6A) modification provides an important epitranscriptomic mechanism that critically regulates RNA metabolism and function. However, how m6A writers attain substrate specificities remains unclear. We report the 3.1 Å-resolution crystal structure of human CCHC zinc finger-containing protein ZCCHC4, a 28S rRNA-specific m6A methyltransferase, bound to S-adenosyl-L-homocysteine. The methyltransferase (MTase) domain of ZCCHC4 is packed against N-terminal GRF-type and C2H2 zinc finger domains and a C-terminal CCHC domain, creating an integrated RNA-binding surface. Strikingly, the MTase domain adopts an autoinhibitory conformation, with a self-occluded catalytic site and a fully-closed cofactor pocket. Mutational and enzymatic analyses further substantiate the molecular basis for ZCCHC4-RNA recognition and a role of the stem-loop structure within substrate in governing the substrate specificity. Overall, this study unveils unique structural and enzymatic characteristics of ZCCHC4, distinctive from what was seen with the METTL family of m6A writers, providing the mechanistic basis for ZCCHC4 modulation of m6A RNA methylation.

A series of novel red‐emitting iridium dendrimers functionalized with oligocarbazole host dendrons up to the third generation (red‐G3) have been synthesized by a convergent method, and their photophysical, electrochemical, and electroluminescent properties have been investigated. In addition to controlling the intermolecular interactions, oligocarbazole‐based dendrons could also participate in the electrochemical and charge‐transporting process. As a result, highly efficient electrophosphorescent devices can be fabricated by spin‐coating from chlorobenzene solution in different device configurations. The maximum external quantum efficiency (EQE) based on the non‐doped device configuration increases monotonically with increasing dendron generation. An EQE as high as 6.3% was obtained as for the third generation dendrimer red‐G3, which is about 30 times higher than that of the prototype red‐G0. Further optimization of the device configuration gave an EQE of 11.8% (13.0 cd A−1, 7.2 lm W−1) at 100 cd m−2 with CIE coordinates of (0.65, 0.35). The state‐of‐the‐art performance indicated the potential of these oligocarbazole‐based red iridium dendrimers as solution processible emissive materials for organic light‐emitting diode applications.