Colon cancer is one of the most common malignant tumors, but there are still a few validated biomarkers of colon cancer. Exosome-mediated microRNAs (miRNAs) have been recognized as potential biomarkers in cancers, and miRNAs can regulate a variety of genes. Recently, Fusobacterium nucleatum was discovered in the tissues of human colon cancer patients. Its role in colon cancer was highlighted. F. nucleatum may contribute to the progression of colon cancer through the mechanism of exosome-mediated miRNAs transfer. However, the exosomal miRNAs regulation mechanism by F. nucleatum in colon cancer is not well known. Thus, we performed next-generation sequencing to investigate the overall pattern of exosomal miRNAs expression in the colon cancer cell culture supernatant. We have confirmed the alterations of various exosomal miRNAs. In addition, to investigate the function of exosomal miRNAs, a Kyoto Encyclopedia of Genes and Genomes analysis was performed on the target genes of changed miRNAs. Potential target genes were associated with a variety of signaling pathways, and one of these pathways was related to colorectal cancer. These findings suggested that F. nucleatum can alter exosomal miRNAs released from colorectal cancer cells. Furthermore, exosomal miRNAs altered by F. nucleatum could be potential biomarkers for the diagnosis and therapy of colon cancer.

Exosomes are Nano-sized lipid vesicles secreted from mammalian cells containing diverse cellular materials such as proteins, lipids, and nucleotides. Multiple lines of evidence indicate that in saliva, exosomes and their contents such as microRNAs (miRNAs) mediate numerous cellular responses upon delivery to recipient cells. The objective of this study was to characterize the different expression profile of exosomal miRNAs in saliva samples, periodically isolated from a single periodontitis patient. Unstimulated saliva was collected from a single patient over time periods for managing periodontitis. MicroRNAs extracted from each phase were investigated for the expression of exosomal miRNAs. Salivary exosomal miRNAs were analyzed using Affymetrix miRNA arrays and prediction of target genes and pathways for its different expression performed using DIANA-mirPath, a web-based, computational tool. Following the delivery of miRNA mimics (hsa-miR-4487, -4532, and -7108-5p) into human gingival fibroblasts, the expression of pro-inflammatory cytokines and activation of the MAPK pathway were evaluated through RT-PCR and western blotting. In each phase, 13 and 43 miRNAs were found to be differently expressed (|FC| ≥ 2). Among these, hsa-miR-4487 (|FC|=9.292005) and hasmiR- 4532 (|FC|=18.322697) were highly up-regulated in the clinically severe phase, whereas hsa-miR-7108-5p (|FC|= 12.20601) was strongly up-regulated in the clinically mild phase. In addition, the overexpression of miRNA mimics in human gingival fibroblasts resulted in a significant induction of IL-6 mRNA expression and p38 phosphorylation. The findings of this study established alterations in salivary exosomal miRNAs which are dependent on the severity of periodontitis and may act as potential candidates for the treatment of oral inflammatory diseases.

Tumor cells, especially in a malignant form, proliferate rapidly that blood supply within the tumors becomes limited, leading to a condition of insufficient oxygen supply. Such hypoxic condition is known to impair the viability of cancer cells, but it can also be a factor to facilitate the appearance of cells with a higher degree of malignancy. Indeed, the hypoxic condition created within malignant tumors may contribute to promoting their aggressive behaviors, including tumor invasion and metastasis, and to the development of resistance to various therapeutic modalities such as chemotherapy. Recently, microRNAs, a group of short RNA fragments consisting of 18 to 20 nucleotides, have been shown to participate in regulating genes important for cell survival, differentiation and apoptosis. Since their discovery, modulation of these microRNAs has been a focus of intensive studies with regard to their significance on gene regulation and various aspects of cell biology. In this study, we investigated hypoxia-induced alterations in microRNAs in oral squamous cell carcinoma (OSCC) cells and discussed consequential gene modulation and relevant cellular responses.

Cloning or somatic cell nuclear transfer (SCNT) using adult somatic cell to derive cloned embryos is a promising new technology with potential applications in both agriculture and regenerative medicine. Mammalian embryos derived by nuclear transfer are capable of development to the blastocyst stage with a relatively high efficiency of 30～ 50%. However, in full-time development, usually only 2% of NT embryos can result in live births due to abnormalities in placenta formation. In SCNT embryos, the donor cell nucleus is epigenetically reprogrammed by oocyte cytoplasm during development. Incomplete reprogramming of the donor cell genome is considered a major reason for low cloning efficiency. Aberrant epigenetic modifications include DNA methylation, histone modification and X-chromosome-inactivation. Due to a lack of basic knowledge regarding the embryos following nuclear transfer, the success rate of cloning is low. Therefore, elucidation of the molecular mechanism of SCNT embryo development will be of great value for further research. MicroRNAs (microRNA) are single-strand RNA molecules of about 19 23 nucleotides in length, which regulate gene expression by imperfect base pairing with target mRNA, subsequently guiding mRNA cleavage or translational repression. Since the first discovery and functional annotation in 1993 of the small RNA, lin-4 and let-7, which are involved in developmental timing and gene regulation during C. elegans larval development, microRNAs have received scientific attention. Now hundreds of microRNAs have been identified in various multicellular organisms, and many microRNAs have been shown to be evolutionarily conserved. The roles proposed for this novel class of tiny RNA molecules are diverse. They are likely to be involved in developmental timing, differentiation, cell proliferation, signaling pathways, apoptosis, metabolism, heterochromatin formation, genome rearrangement, brain development and carcinogenesis. Currently (2006- present) we are working to determine the role of microRNAs on the epigenetic regulation of fertilized and cloned embryo development. The general hypothesis of our research is that genetic and epigenetic factors regulate the development of preimplantation mammalian embryos, and aberrant modulations in cloned embryos are causes of abnormal development and low success rate of cloned embryos.

Spatiotemporal expressions of microRNAs (miRNAs) are altered by the physiological states of cells which could be influenced by microenvironment. Function of miRNAs has been focused as a new regulator of gene expressions and cell differentiation in human health and diseases. We found and identified the several miRNAs, which were related to developmental competence of preimplantation and implantation process of mouse blastocysts and outgrowth embryos by microarray-based bioinformatical studies. In this study, we evaluated three miRNAs expressions related to third cleavage event in conditioned media (CM) and blastocysts. Mouse 2-cell stage embryos were collected and monitored for 9 hours. The embryos were divided two groups as early third cleavage before 9 hours of collection and late third cleavage after 9 hours of collection. They were cultured to blastocyst stage up to day-5 after hCG injection. The total number of cells and the number of cells with fragmented DNA were assessed in blastocysts by terminal dUTP nick-end labelling (TUNEL) staining and DAPI staining. Mean cell number of early third cleavage group was significantly higher than that of late third cleavage group (105.3±8.0 vs 81.8±7.0, p<0.05), but apoptotic index was not different. The miRNAs of CM and blastocysts from early and late group were prepared, and quantified by qRT-PCR with TaqMan probes. The expression levels of three miRNAs (mmu-let-7b, mmu-miR-183, and mmu-miR-429) in CM and blastocysts were slightly upregulated in late third cleavage group. Our study suggested that the expression level of miRNAs could be altered with embryo quality, and miRNAs in CM may be used to predict miRNAs expression of embryos and developmental competence.

DGCR8 is a RNA-binding protein working with DROSHA to produce pre-microRNA in the nucleus, while DICER does not only mature microRNA but also endogenous siRNAs in the cytoplasm. Here, we have produced Dgcr8 conditional knock-out mice using progesterone receptor (PR)-Cre (Dgcr8flox/flox; PRcre/+ mice, Dgcr8d/d) and demonstrated that canonical microRNAs dependent of DROSHA-DGCR8 complex are required for uterine development as well as female fertility in mice. Adult Dgcr8d/d females did not undergo regular reproductive cycle and produce any pups when housed with fertile males, whereas administration of exogenous gonadotropins induced normal ovulation with corpus luteal formation in these mice. Ovulated oocytes from Dgcr8d/d mice had comparable fertilization potentials and were normally developed to the blastocyst after fertilization as compared to those in control Dgcr8f/f mice. Interestingly, PR-Cre-dependent Dgcr8 deletion showed aberrant infiltration of acute inflammatory immune cells to female reproductive organs only when Dgcr8d/d mice were mated with male mice. With respect to uterine development, gross morphology, histology, and weight of Dgcr8d/d uterus were similar to those of control at 3-week-old age. However, multiple uterine abnormalities were noticeable at 4-week-old age when PR expression is significantly increased, and these deformities became severe onwards. Gland formation and myometrial layers were significantly reduced, and stromal cell compartment did not expand and became atrophic during uterine development in these mice. These results were consistent with aberrantly reduced cell proliferation in stromal cell compartments of Dgcr8d/d mice. Collectively, our results suggest that DGCR8 dependent-canonical microRNAs are essential for development and physiology of the uterus with respect to morphogenesis, proper immune modulation, reproductive cycle, and steroid hormone responsiveness in mice.

Nitrogen is a key component in the growth of crop plant. To increase the yield of crops, an enormous amount of nitrogen fertilizer is currently being used, which increases the total production cost and leads to environmental pollution by the residual nitrogen sources. For these reasons, researchers have tried to improve the crop’s nitrogen use efficiency (NUE) as a solution for reducing the amount of nitrogen fertilizer used. MicroRNAs are a class of small non-coding RNAs regulating the expression of target genes. Recent studies suggested that the expression pool of microRNAs changes in response to a variety of nutrient deficiencies and that such changes play important roles in adapting to or resisting the consequential nutritional stresses. Here, we aim to identify and characterize rice microRNAs whose expression changes upon nitrogen starvation and re-supplementation. By applying RNA-Seq, we observed that the expression of a set of genes involved in nitrogen assimilation was altered in response to nitrogen deprivation. We also found that a considerable number of microRNAs exhibited dynamic expression changes in a nitrogen supply state-dependent manner and that the expression of genes targeted by those differentially regulated microRNAs was altered reciprocally. Our study suggests that microRNAs may have roles in regulating the response of rice to nitrogen supply state and subsequently modulating NUE.

Osteosarcoma (OS) is one of the most common malignant primary bone tumors and NF-κB appears to play a causative role, but the mechanisms are poorly understood. OS is one of the pleomorphic, highly metastasized and invasive neoplasm which is capable to generate osteoid, osteoclast and osteoblast matrix. Its high incidence has been reported in adolescent and children. Cell signal cascade is the pivotal functional mechanism acquired during the differentiation, proliferation, growth and survival of the cells in neoplasm including OS. The major limitation to the success of chemotherapy in OS is the development of multidrug resistance (MDR). Answers to all such queries might come from the knock-in experiments in which the combined approach of miRNAs with NF-κB pathway is put into use. Abnormal miRNAs can modulate several epigenetical switching as a hallmark of number of diseases via different cell signaling. Studies on miRNAs have opened up the new avenues for both the diagnosis and treatment of cancers including OS. Collectively, through the present study an attempt has been made to establish a new systematic approach for the investigation of microRNAs, biophysiological factors and their target pairs with NF-κB to ameliorate oncogenesis with the “bridge between miRNAs and NF- κB”. The application of NF-κB inhibitors in combination with miRNAs is expected to result in a more efficient killing of the cancer stem cells and a slower or less likely recurrence of cancer.

MicroRNAs (miRNAs) are single-stranded, small non-coding RNAs which are critical for gene regulatory networks by directing the translational repression or degradation of complementary target mRNAs. They can be divided into two subclasses: canonical and non-canonical miRNAs. Canonical miRNAs are produced from long primary transcripts by sequential complex events in which RNA III enzymes such as Drosha and Dicer and accessory factors such as DGCR8 and Argonautes work cooperatively. DGCR8 is a RNA-binding protein that assists Drosha to process canonical miRNAs in the nucleus. To understand function of canonical miRNAs in uterine physiology, we have characterized uterine phenotypes of uterine-specific DGCR8 knock-out mice (uDGCR8 KO, DGCR8flox/flox; PRcre/+), and hormonal regulation of expression profiles of major factors working for miRNA biogenesis in the uterus. Gross morphological and histological analyses, immunohistochemistry, PCR and realtime RT-PCR were performed. While DGCR8 and Drosha do not seem to be regulated by ovarian steroid hormones, expression of Dicer, Exportin 5 and Argonaute 2 was transiently increased by E2 but not by P4. Combination of E2+P4 did not have any additional effects on their expression profiles. Genomic DNA PCR analyses showed that while DGCR8 gene is not completely deleted in the uterus, DGCR8 is specifically deleted in the uterus where PR is strongly expressed. uDGCR8 KO females bred with fertile males did not produce any offspring, suggesting that these mice are infertile. Vaginal smear analyses provided evidence that these mice do not undergo estrous cycle. Whereas gross morphology and histological analyses of uteri of 3-week-old uDGCR8 KO mice is similar to that of DGCR8flox/flox mice (control), uteri of 5- and 8-week-old mice are extremely thinner and shorter than those of control mice. These results were supported by significant decrease in uterine weight/body weight of uDGCR8 KO mice at 5-week-old age onward. Interestingly, this phenotype is reflected by significant increase of PR expression in the uteri of 4-week-old mice. Expression of DGCR8 and Dicer is significantly increased after birth. BrdU incorporation experiments showed that cell proliferation governed by ovarian steroid hormones does not normally occur in these mutant mice. Furthermore, artificial decidualization does not occur in these mice. Collectively, these results conclude that canonical miRNAs plays critical roles in normal uterine development and steroid hormone-dependent uterine function.