MicroRNA‐379 suppresses osteosarcoma progression by targeting PDK1

Osteosarcoma is the most common primary bone tumour. Increasing evidence has demonstrated the pathogenic role of microRNA (miRNAs) dysregulation in tumour development. miR‐379 was previously reported to function as an oncogenic or tumour‐suppressing miRNA in a tissue‐dependent manner. However, its function in osteosarcoma remains unknown. In this study, we found that the expression of miR‐379 was downregulated in osteosarcoma tissues and cell lines. Further functional characterization revealed that miR‐379 suppressed osteosarcoma cell proliferation and invasion in vitro and retarded the growth of osteosarcoma xenografts in vivo. Mechanistically, PDK1 was identified as the direct target of miR‐379 in osteosarcoma, in which PDK1 expression was up‐regulated and showed inverse correlation with miR‐379. Enforced expression of PDK1 promoted osteosarcoma cell proliferation and rescued the anti‐proliferative effect of miR‐379. These data suggest that miR‐379 could function as a tumour‐suppressing miRNA via targeting PDK1 in osteosarcoma.     

Murine intestinal organoids resemble intestinal epithelium in their microRNA profiles

Intestinal organoids were established as an ex vivo model of the intestinal epithelium. We investigated whether organoids resemble the intestinal epithelium in their microRNA (miRNA) profiles. Total RNA samples were obtained from crypt and villus fractions in murine intestine and from cultured organoids. Microarray analysis showed that organoids largely resembled intestinal epithelial cells in their miRNA profiles. In silico prediction followed by qRT-PCR suggested that six genes are regulated by corresponding miRNAs along the crypt-villus axis, suggesting miRNA regulation of epithelial cell renewal in the intestine. However, such expression patterns of miRNAs and their target mRNAs were not reproduced during organoids maturation. This might be due to lack of luminal factors and endocrine, nervous, and immune systems in organoids and different cell populations between in vivo epithelium and organoids. Nevertheless, we propose that intestinal organoids provide a useful in vitro model to investigate miRNA expression in intestinal epithelial cells.     

Expression of VEGFA‐regulating miRNAs and mortality in wet AMD

MicroRNAs (miRNAs) regulate gene expression; many of them act in the retinal pigment epithelium (RPE), and RPE degeneration is known to be a critical factor in age‐related macular degeneration (AMD). Repeated injections with anti‐VEGFA (vascular endothelial growth factor A) are the only effective therapy in wet AMD. We investigated the correlation between the expression of 18 miRNAs involved in the regulation of the VEGFA gene in serum of 76 wet AMD patients and 70 controls. Efficacy of anti‐VEGFA treatment was evaluated by counting the number of injections delivered up to 12 years. In addition, we compared the relative numbers of deaths in patient with AMD and control groups. We observed a decreased expression of miR‐34‐5p, miR‐126‐3p, miR‐145‐5p and miR‐205‐5p in wet AMD patients as compared with controls. These miRNAs are involved in the regulation of angiogenesis, cytoprotection and protein clearance. No miRNA was significantly correlated with the treatment outcome. Wet AMD patients had greater mortality than controls, and their survival was inversely associated with the number of anti‐VEGFA injections per year. No association was observed between miRNA expression and mortality. Our study emphasizes the need to clarify the role of miRNA regulation in AMD pathogenesis.     

miRNA‐940 reduction contributes to human Tetralogy of Fallot development

Tetralogy of Fallot (TOF) is a complex congenital heart defect and the microRNAs regulation in TOF development is largely unknown. Herein, we explored the role of miRNAs in TOF. Among 75 dysregulated miRNAs identified from human heart tissues, miRNA‐940 was the most down‐regulated one. Interestingly, miRNA‐940 was most highly expressed in normal human right ventricular out‐flow tract comparing to other heart chambers. As TOF is caused by altered proliferation, migration and/or differentiation of the progenitor cells of the secondary heart field, we isolated Sca‐1⁺ human cardiomyocyte progenitor cells (hCMPC) for miRNA‐940 function analysis. miRNA‐940 reduction significantly promoted hCMPCs proliferation and inhibited hCMPCs migration. We found that JARID2 is an endogenous target regulated by miRNA‐940. Functional analyses showed that JARID2 also affected hCMPCs proliferation and migration. Thus, decreased miRNA‐940 affects the proliferation and migration of the progenitor cells of the secondary heart field by targeting JARID2 and potentially leads to TOF development.     

Identification of microRNAs and their corresponding targets involved in the susceptibility interaction of wheat response to Puccinia striiformis f. sp. tritici

MicroRNAs (miRNAs) play very important roles in plant defense responses. However, little is known about their roles in the susceptibility interaction between wheat and Puccinia striiformis f. sp. tritici (Pst). In this study, two miRNA libraries were constructed from the leaves of the cultivar Xingzi 9104 inoculated with the virulent Pst race CYR32 and sterile water, respectively. A total of 1316 miRNA candidates, including 173 known miRNAs that were generated from 98 pre‐miRNAs, were obtained. The remaining 1143 miRNA candidates included 145 conserved and 998 wheat‐specific miRNAs that were generated from 87 and 1088 pre‐miRNAs, respectively. The 173 known and 145 conserved miRNAs were sub‐classified into 63 miRNA families. The target genes of wheat miRNAs were also confirmed using degradome sequencing technology. Most of the annotated target genes were related to signal transduction or energy metabolism. Additionally, we found that miRNAs and their target genes form complicated regulation networks. The expression profiles of miRNAs and their corresponding target genes were further analyzed by quantitative real‐time polymerase chain reaction (qRT‐PCR), and the results indicate that some miRNAs are involved in the compatible wheat‐Pst susceptibility interaction. Importantly, tae‐miR1432 was highly expressed when wheat was challenged with CYR32, and the corresponding target gene, predicted to be a calcium ion‐binding protein, also exhibited upregulated expression but a divergent expression trend. PC‐3P‐7484, a specific wheat miRNA, was highly expressed in the wheat response to Pst infection, while the expression of the corresponding target gene ubiquillin was dramatically downregulated. These data provide the foundation for evaluating the important regulatory roles of miRNAs in wheat‐Pst susceptibility interaction.     

Altered microRNA expression in bovine skeletal muscle with age

Age‐dependent decline in skeletal muscle function leads to several inherited and acquired muscular disorders in elderly individuals. The levels of microRNAs (miRNAs) could be altered during muscle maintenance and repair. We therefore performed a comprehensive investigation for miRNAs from five different periods of bovine skeletal muscle development using next‐generation small RNA sequencing. In total, 511 miRNAs, including one putatively novel miRNA, were identified. Thirty‐six miRNAs were differentially expressed between prenatal and postnatal stages of muscle development including several myomiRs (miR‐1, miR‐206 and let‐7 families). Compared with miRNA expression between different muscle tissues, 14 miRNAs were up‐regulated and 22 miRNAs were down‐regulated in the muscle of postnatal stage. In addition, a novel miRNA was predicted and submitted to the miRBase database as bta‐mir‐10020. A dual luciferase reporter assay was used to demonstrate that bta‐mir‐10020 directly targeted the 3′‐UTR of the bovine ANGPT1 gene. The overexpression of bta‐mir‐10020 significantly decreased the DsRed fluorescence in the wild‐type expression cassette compared to the mutant type. Using three computational approaches – miranda , pita and rnahybrid – these differentially expressed miRNAs were also predicted to target 3609 bovine genes. Disease and biological function analyses and the KEGG pathway analysis revealed that these targets were statistically enriched in functionality for muscle growth and disease. Our miRNA expression analysis findings from different states of muscle development and aging significantly expand the repertoire of bovine miRNAs now shown to be expressed in muscle and could contribute to further studies on growth and developmental disorders in this tissue type.     

The variant at TGFBRAP1 is significantly associated with type 2 diabetes mellitus and affects diabetes‐related miRNA expression

While the transforming growth factor‐β1 (TGF‐β1) regulates the growth and proliferation of pancreatic β‐cells, its receptors trigger the activation of Smad network and subsequently induce the insulin resistance. A case‐control was conducted to evaluate the associations of the polymorphisms of TGF‐β1 receptor‐associated protein 1 (TGFBRAP1) and TGF‐β1 receptor 2 (TGFBR2) with type 2 diabetes mellitus (T2DM), and its genetic effects on diabetes‐related miRNA expression. miRNA microarray chip was used to screen T2DM‐related miRNA and 15 differential expressed miRNAs were further validated in 75 T2DM and 75 normal glucose tolerance (NGT). The variation of rs2241797 (T/C) at TGFBRAP1 showed significant association with T2DM in case‐control study, and the OR (95% CI) of dominant model for cumulative effects was 1.204 (1.060‐1.370), Bonferroni corrected P < 0.05. Significant differences in the fast glucose and HOMA‐β indices were observed amongst the genotypes of rs2241797. The expression of has‐miR‐30b‐5p and has‐miR‐93‐5p was linearly increased across TT, TC, and CC genotypes of rs2241797 in NGT, P_trend values were 0.024 and 0.016, respectively. Our findings suggest that genetic polymorphisms of TGFBRAP1 may contribute to the genetic susceptibility of T2DM by mediating diabetes‐related miRNA expression.