3D-printed bioink loading with stem cells and cellular vesicles for periodontitis-derived bone defect repair.

The suitable microenvironment of bone regeneration is critically important for periodontitis-derived bone defect repair. Three major challenges in achieving a robust osteogenic reaction are the exist of oral inflammation, pathogenic bacteria invasion and unaffluent seed cells. Herein, a customizable and multifunctional 3D-printing module was designed with glycidyl methacrylate (GMA) modified epsilon-poly-L-lysine (EPLGMA) loading periodontal ligament stem cells (PDLSCs) and myeloid-derived suppressive cells membrane vesicles (MDSCs-MV) bioink (EPLGMA/PDLSCs/MDSCs-MVs, abbreviated as EPM) for periodontitis-derived bone defect repair. The EPM showed excellent mechanical properties and physicochemical characteristics, providing a suitable microenvironment for bone regeneration.In vitro, EPMs presented effectively kill the periodontopathic bacteria depend on the natural antibacterial properties of the EPL. Meanwhile, MDSCs-MV was confirmed to inhibit T cells through CD73/CD39/adenosine signal pathway, exerting an anti-inflammatory role. Additionally, seed cells of PDLSCs provide an adequate supply for osteoblasts. Moreover, MDSCs-MV could significantly enhance the mineralizing capacity of PDLSCs-derived osteoblast. In the periodontal bone defect rat model, the results of micro-CT and histological staining demonstrated that the EPM scaffold similarly had an excellent anti-inflammatory and bone regeneration efficacyin vivo. This biomimetic and multifunctional 3D-printing bioink opens new avenues for periodontitis-derived bone defect repair and future clinical application.

Multidifferentiation potential of dental-derived stem cells.

Tooth-related diseases and tooth loss are widespread and are a major public health issue. The loss of teeth can affect chewing, speech, appearance and even psychology. Therefore, the science of tooth regeneration has emerged, and attention has focused on tooth regeneration based on the principles of tooth development and stem cells combined with tissue engineering technology. As undifferentiated stem cells in normal tooth tissues, dental mesenchymal stem cells (DMSCs), which are a desirable source of autologous stem cells, play a significant role in tooth regeneration. Researchers hope to reconstruct the complete tooth tissues with normal functions and vascularization by utilizing the odontogenic differentiation potential of DMSCs. Moreover, DMSCs also have the ability to differentiate towards cells of other tissue types due to their multipotency. This review focuses on the multipotential capacity of DMSCs to differentiate into various tissues, such as bone, cartilage, tendon, vessels, neural tissues, muscle-like tissues, hepatic-like tissues, eye tissues and glands and the influence of various regulatory factors, such as non-coding RNAs, signaling pathways, inflammation, aging and exosomes, on the odontogenic/osteogenic differentiation of DMSCs in tooth regeneration. The application of DMSCs in regenerative medicine and tissue engineering will be improved if the differentiation characteristics of DMSCs can be fully utilized, and the factors that regulate their differentiation can be well controlled.

Analysis of YM-216391 biosynthetic gene cluster and improvement of the cyclopeptide production in a heterologous host.

YM-216391, an antitumor natural product, represents a new class of cyclic peptides containing a polyoxazole-thiazole moiety. Herein we describe its gene cluster encoding the biosynthetic paradigm featuring a ribosomally synthesizing precursor peptide followed by a series of novel posttranslational modifications, which include (i) cleavage of both N-terminal leader peptide and C-terminal extension peptide and cyclization in a head-to-tail fashion, (ii) conversion of an L-Ile to D-allo-Ile, and (iii) ß-hydroxylation of Phe by a P450 monooxygenase followed by further heterocyclization and oxidation to form a phenyloxazole moiety. The cluster was heterologously expressed in Streptomyces lividans to bypass difficult genetic manipulation. Deletion of the ymR3 gene, encoding a putative transcriptional regulator, increased the YM-216391 yield about 20-fold higher than the original yields for the heterologous expression of wild-type cluster, which set the stage for further combinatorial biosynthesis.

[Genetic polymorphism of bluegrass cultivars detected by RAPDs].

Kentucky bluegrass (Poa pratensis L.) is a hardy, persistent forage and turf grass adapted to a wide range of soils and climates. Its ever-increasing adoption in highly cared-for sports fields has attracted the attention of many seed companies. However in the past, the breeding of elite varieties was often hampered by the extreme complexity of the genome. The polymorphism is important for broading the genetic basis and may be exploited for application of heterosis. The genetic relationship of 16 bluegrass cultivars, including 15 accessions Kentucky bluegrass cultivars and 1 entries Canada bluegrass (Poa compressa L.) cultivar from different breeding company were analyzed using 25 RAPD markers. 25 RAPD primers generated 218 bands, of which 196 bands (89.91%) were polymorphism. It showed that the Canada Bluegrass was separated from other Kentucky Bluegrass and genetic polymorphism in the Kentucky Bluegrass cultivars was low, the genetic similarity among the cultivars fell between 66%-98%. Dendrogram obtained using these molecular markers were partly in agreement with their separated morphologic character. Cultivars from the same company were not clustered in one group.