Reciprocal relationship usually exists between osteoblastogenesis and adipogenesis, with factors stimulating one of these processes at the same time inhibiting the other. In the present study, miR-30e was found to be involved in the reciprocal regulation of osteoblast and adipocyte differentiation. Our data indicated that miR-30e was induced in primarily cultured mouse bone marrow stromal cell, mesenchymal cell line C3H10T1/2 and preadipocyte 3T3-L1 after adipogenic treatment. Conversely, it was reduced in mouse stromal line ST2 and preosteoblast MC3T3-E1 after osteogenic treatment. Enforced expression of miR-30e in 3T3-L1 significantly suppressed the growth of the cells and induced the preadipocytes to differentiate into mature adipocytes, along with increased expression of adipocyte-specific transcription factors peroxisome proliferator-activated receptor-γ (PPARγ), CCAAT/enhancer binding protein-α (C/EBPα) and C/EBPβ, and the marker gene aP2. In contrast, inhibition of the endogenous miR-30e enhanced the cell growth and repressed preadipocytes to differentiate. Conversely, supplementing miR-30e activity blocked, whereas knocking down miR-30e enforced the preosteoblast MC3T3-E1 to fully differentiate. Furthermore, miR-30e overexpression stimulated adipocyte formation and inhibited osteoblast differentiation from marrow stromal cells. Low-density lipoprotein receptor-related protein 6 (LRP6), one of the critical coreceptor for Wnts, was shown to be a direct target of miR-30e by using the luciferase assay. Knockdown of LRP6 in 3T3-L1 cells downregulated β-catenin/T-cell factor (TCF) transcriptional activity and dramatically potentiated the differentiation of the cells into mature adipocytes. Taken together, the present work suggests that the expression of miR-30e is indispensable for maintaining the balance of adipocytes and osteoblasts by targeting the canonical Wnt/β-catenin signaling.
Background:The effective mechanisms of microRNAs (miRNAs) functions as oncogenes or tumour suppressors in human hepatocellular carcinoma (HCC) are still obscure. Here, we investigated the function and expression of miR-1228 in HCC.Methods:The role of miR-1228 in HCC was determined by colony formation, transwell, and nude mice xenograft experiments. miR-1228 target gene were identified by EGFP reporter assays, real-time PCR, and western blot analysis. Dual-luciferase reporter assay and real-time PCR analysis are used to examine the regulation of p53.Results:miR-1228 promoted proliferation and metastasis, and facilitated the transition of cell cycle in hepatoma cells. miR-1228 downregulated p53 expression by binding to its 3′UTR. The ectopic expression of p53 abrogated the phenotypes induced by miR-1228. An inverse correlation existed between miR-1228 and p53 expression in hepatoma tissues compared with the adjacent tissues and three hepatoma cell lines. Moreover, we found that p53 suppressed the expression and promoter activity of miR-1228.Conclusions:miR-1228 functions as an oncogene by promoting cell cycle progression and cell mobility and negatively regulates the expression of p53. p53 downregulation in turn leads to an increase in miR-1228 expression, thereby forming a positive feedback loop that contributes to cancerogenesis in HCC.
Aims: The aims of this study are to obtain the draft genome sequence of Streptomyces coelicoflavus ZG0656, which produces novel acarviostatin family α‐amylase inhibitors, and then to reveal the putative acarviostatin‐related gene cluster and the biosynthetic pathway. Methods and Results: The draft genome sequence of S. coelicoflavus ZG0656 was generated using a shotgun approach employing a combination of 454 and Solexa sequencing technologies. Genome analysis revealed a putative gene cluster for acarviostatin biosynthesis, termed sct‐cluster. The cluster contains 13 acarviostatin synthetic genes, six transporter genes, four starch degrading or transglycosylation enzyme genes and two regulator genes. On the basis of bioinformatic analysis, we proposed a putative biosynthetic pathway of acarviostatins. The intracellular steps produce a structural core, acarviostatin I00‐7‐P, and the extracellular assemblies lead to diverse acarviostatin end products. Conclusions: The draft genome sequence of S. coelicoflavus ZG0656 revealed the putative biosynthetic gene cluster of acarviostatins and a putative pathway of acarviostatin production. Significance and Impact of the Study: To our knowledge, S. coelicoflavus ZG0656 is the first strain in this species for which a genome sequence has been reported. The analysis of sct‐cluster provided important insights into the biosynthesis of acarviostatins. This work will be a platform for producing novel variants and yield improvement.
Due to progressive population aging, a new dementia case occurs at every 3 seconds, placing a heavy burden of disease. Identifying potential risk or preventive factors is emphasized owing to a lack of effective treatment for dementia. There has been emerging evidence on the link of certain dietary components, particularly polyphenols, to brain wellness and cognitive outcomes. Findings from animal and in vitro studies appear more consistent and conclusive. However, such an association has not been investigated in depth in human beings. In this review, we examined studies on the effect of dietary polyphenols (including flavonoids, curcumin, and resveratrol) on cognitive function. Intervention in early stages of dementia/Alzheimer’s disease might be a target to slow down age-related cognitive decline before disease onset. We summarized 28 epidemiological studies (8 cross-sectional and 20 cohort studies) and 55 trials in this review. Preliminary evidence from epidemiological data provides the necessity for intervention trials, even though the measures of polyphenol intake tend to be less precise. Clinical trials are in favor of the role of some polyphenols in benefiting specific domains of cognition. This review also describes the divergence of results and current limitations of research in this field.
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