MicroRNA-34a modulates the Notch signaling pathway in mice with congenital heart disease and its role in heart development.

The objective of the study was to elucidate the mechanism by which microRNA-34a (miR-34a) influences heart development and participates in the pathogenesis of congenital heart disease (CHD) by targeting NOTCH-1 through the Notch signaling pathway. Forty D7 pregnant mice were recruited for the purposes of the study and served as the CHD (n=20, successfully established as CHD model) and normal (n=20) groups. The positive expression of the NOTCH-1 protein was evaluated by means of immunohistochemistry. Embryonic endocardial cells (ECCs) were assigned into the normal, blank, negative control (NC), miR-34a mimics, miR-34a inhibitors, miR-34a inhibitors+siRNA-NOTCH-1, siRNA-NOTCH-1, miR-34a mimics+NOTCH-1 OE and miR-34a mimics+crispr/cas9 (mutant NOTCH-1) groups. The expressions of miR-34a, NOTCH-1, Jagged1, Hes1, Hey2 and Csx in cardiac tissues and ECCs were determined by both RT-qPCR and western blotting methods. MTT assay and flow cytometry were conducted for cell proliferation and apoptosis measurement. A dual luciferase reporter assay was applied to demonstrate that NOTCH-1 was the target gene of miR-34a. In comparison to the normal group, the expressions of miR-34a, Jagged1, Hes1 and Hey2 displayed up-regulated levels, while the expressions of NOTCH-1 and Csx were down-regulated in the CHD group. Compared with the blank and NC groups, the miR-34a mimics and siRNA-NOTCH-1 groups displayed reduced expressions of NOTCH-1 and Csx as well as a decreased proliferation rate, higher miR-34a, Jagged1, Hes1 and Hey2 expressions and an increased rate of apoptosis; while an reverse trend was observed in the miR-34a inhibitors group. The expressions of MiR-34a recorded increased levels in the miR-34a mimics+NOTCH-1 OE and miR-34a mimics+crispr/cas9 (mutant NOTCH-1) groups, however no changes in the expressions of NOTCH-1, Jagged1, Hes1, Hey2, Csx, as well as cell proliferation and apoptosis were observed when compared to the blank and NC groups. The results of our study demonstrated that miR-34a increases the risk of CHD through its downregulation of NOTCH-1 by modulating the Notch signaling pathway.

Comparisons of Effects on Intestinal Short-Chain Fatty Acid Concentration after Exposure of Two Glycosidase Inhibitors in Mice.

Acarbose and voglibose are the most widely used diabetes drugs as glycosidase inhibitors. In this study, the use of these two inhibitors significantly increased the content of starch in large intestine, and altered the concentration of short-chain fatty acids (SCFAs) by affecting the intestinal microbiota. However, there are some differences in the intestinal microbiome of the two groups of mice, mainly in bacteria such as Bacteroidaceae bacteroides and Desulfovibrionaceae desulfovibrio. The productions of acetate and propionate in caecum in voglibose group were significantly higher than those in acarbose group and two kinds of glycosidase inhibitors were close in the production of butyrate in caecum. The Tax4Fun analysis based on Kyoto Encyclopedia of Genes and Genomes (KEGG) data indicated that different productions of acetate and propionate between acarbose group and voglibose group may be related to 2-oxoisovalerate dehydrogenase and pyruvate oxidase. In addition, in-vitro experiments suggested that voglibose had less effect on epithelial cells than acarbose after direct stimulation. According to the recent researches of SCFAs produced by intestinal microbiota, our comparative study shown higher concentration of these beneficial fatty acids in the lumen of voglibose-treated mice, which implied a lower level of inflammation.

Broadening oncological boundaries: the intratumoral microbiota.

The microbiota of solid tumors was identified >100 years ago; however, heterogeneous composition and diversity have been revealed only recently. Growing evidence has suggested that several functional mechanisms of the intratumoral microbiota affect tumorigenesis and progression, suggesting that the intratumoral microbiota is a promising biomarker for multiple cancers. The low biomass of the intratumoral microbiota poses a major challenge to related research, thus necessitating the use of a multiple-modality integrated framework to resolve this dilemma. Advanced techniques such as single-cell sequencing provide significant clues, and the gradual optimization of functional experiments and culture-based methods enables deeper investigation of the underlying mechanisms involved. In this review, we outline the current state of research on the intratumoral microbiota and describe the challenges and comprehensive strategies for future research.

Easy Applied Gelatin-Based Hydrogel System for Long-Term Functional Cardiomyocyte Culture and Myocardium Formation.

Harnessing biomaterials for in vitro tissue construction has long been a research focus because of its powerful potentials in tissue engineering and pharmaceutical industry. Myocardium is a critical cardiac tissue with complex multiple muscular layers. Considering the specific characters of native cardiac tissues, it is necessary to design a biocompatible and biomimetic platform for cardiomyocyte culture and myocardium formation with sustained physiological function. In this study, we developed gelatin-based hydrogels chemically cross-linked by genipin, a biocompatible cross-linker, as cell culture scaffolds. Moreover, to achieve and maintain the functionality of myocardium, for instance, well-organized cardiomyocytes and synchronized contractile behavior, we fabricated gelatin-based hydrogels with patterned microstructure using a microcontact printing technique. Furthermore, graphene oxide (GO), with unprecedented physical and chemical properties, has also been incorporated into gelatin for culturing cardiomyocytes. Our results show that micropatterned genipin-cross-linked gelatin hydrogels are very helpful to promote alignment and maturation of neonatal rat ventricular cardiomyocytes. More interestingly, the presence of GO significantly enhances the functional performance of cardiomyocytes, including an increase in contraction amplitude and cardiac gene expression. The cultured cardiomyocytes reach a well-synchronized contraction within 48 h of cell seeding and keep beating for up to 3 months. Our study provides a new and easy-to-use gelatin-based scaffold for improving physiological function of engineered cardiac tissues, exhibiting promising applications in cardiac tissue engineering and drug screening.