MiRNAs regulate cell communication in osteogenesis-angiogenesis coupling during bone regeneration.

Bone regeneration is a complex process that requires not only the participation of multiple cell types, but also signal communication between cells. The two basic processes of osteogenesis and angiogenesis are closely related to bone regeneration and bone homeostasis. H-type vessels are a subtype of bone vessels characterized by high expression of CD31 and EMCN. These vessels play a key role in the regulation of bone regeneration and are important mediators of coupling between osteogenesis and angiogenesis. Molecular regulation between different cell types is important for coordination of osteogenesis and angiogenesis that promotes bone regeneration. MiRNAs are small non-coding RNAs that predominantly regulate gene expression at the post-transcriptional level and are closely related to cell communication. Specifically, miRNAs transduce external stimuli through various cell signaling pathways and cause a series of physiological and pathological effects. They are also deeply involved in the bone repair process. This review focuses on three signaling pathways related to osteogenesis-angiogenesis coupling, as well as the miRNAs involved in these pathways. Elucidation of the molecular mechanisms governing osteogenesis and angiogenesis is of great significance for bone regeneration.

Non-coding RNAs regulate the BMP/Smad pathway during osteogenic differentiation of stem cells.

MicroRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs) are involved in the regulation of bone metabolism. The BMP/Smad pathway is a key signaling pathway for classical regulation of osteogenic differentiation. Non-coding RNAs (ncRNAs) and the BMP/Smad pathway both have important roles for osteogenic differentiation of stem cells, bone regeneration, and development of bone diseases. There is increasing evidence that ncRNAs interact with the BMP/Smad pathway to regulate not only osteogenic differentiation of stem cells but also progression of bone diseases, such as osteoporosis (OP), myeloma, and osteonecrosis of the femoral head (ONFH), by controlling the expression of bone disease-related genes. Therefore, ncRNAs that interact with BMP/Smad pathway molecules are potential targets for bone regeneration as well as bone disease diagnosis, prevention, and treatment. However, despite extensive studies on ncRNAs associated with the BMP/Smad pathway and osteogenic differentiation of stem cells, there is a lack of comparability. Moreover, some bone disease-associated ncRNAs with low abundance can be difficult to detect and there is a lack of mature delivery systems for their stable translocation to target sites, thus limiting their application. In this review, we summarize the research progress on interactions between ncRNAs and the BMP/Smad pathway during osteogenic differentiation of various stem cells and in the regulation of bone regeneration and bone diseases.

In situ potential-regulated architecture of an ultrafine Ru-based electrocatalyst for ultralow overpotential lithium-oxygen batteries.

An in situ electrochemical reduction strategy is proposed to avoid the aggregation of nano-Ru in lithium batteries for the first time. The high-dispersion face-centered cubic (fcc) nano-Ru is successfully synthesized with an average diameter of 2.0 nm, and the as-assembled lithium-oxygen batteries deliver an excellent cycling performance of 185 cycles and an ultralow overpotential of only 0.20 V at 100 mA g-1.

Single-cell-array biomass-templated architecture of hierarchical porous electrocatalysts for Zn-air and Zn-H2O2 batteries.

Hierarchically macro-meso-microporous ZIF-67/nori-derived electrocatalysts were synthesized by using single-cell-array nori and ZIF-67 as macroporous and microporous templates, and KOH as a meso/micropore-forming reagent. The ZIF-67/nori-800-based Zn-H2O2 battery achieved a high maximum power density, of 476 mW cm-2, and a specific energy density of 964 W h kg-1 at 50 mA cm-2.