The fall armyworm, Spodoptera frugiperda, has developed extremely high levels of resistance to chlorantraniliprole and other classes of insecticides in the field. As microRNAs (miRNAs) play important roles in various biological processes through gene regulation. we examined the miRNA profile of S. frugiperda in response to Chlorantraniliprole, Indoxacarb and Thiamethoxam. Transcriptome analysis showed significant changes in the abundance of some miRNAs after treatment of S. frugiperda larvae with LC20 concentrations of three insecticides. A total of 197 miRNAs were systematically identified from S. frugiperda, and 16, 9, 2 miRNAs were differentially expressed after treatments of three insecticides. Importantly, three miRNAs were significantly downregulated and three were upregulated by RT-qPCR after treatment the LC50 of three insecticides with S. frugiperda larvae. Microinjection of agomirs of these six miRNAs into S. frugiperda larvae resulted in significant changes in mortality rates when exposed to three insecticides. Additionally, we also screened potential target genes for some of differentially expressed miRNAs, which may play important roles in insecticide resistance development. These findings provide valuable insights into the molecular mechanisms of insecticide resistance and underscore the potential of miRNAs as targets for the development of novel pest control strategies in S. frugiperda.

Oral squamous cell carcinoma (OSCC) is the most common type of head and neck cancer and is associated with high recurrence, poor treatment, and low survival rates. Hypoxia-inducible factor-1α (HIF-1α) is a transcription factor that regulates the response to hypoxia, a major factor in the tumor microenvironment that affects tumor development and progression in various cancer types. However, microRNA (miRNA) sequence analysis revealed that only a few miRNAs targeting HIF-1α had been discovered. In the present study, we investigated HIF-1α expression in OSCC and the effect of HIF-1α-targeting miRNAs on the progression and metastatic potential of OSCC. We analyzed public databases to explore which miRNAs target HIF-1α expression. In addition, the expression of proteins involved in the cell cycle, proliferation, and apoptosis in HSC-2 cells was analyzed after miRNA-126 mimic treatment. Furthermore, to investigate the effect of miRNA-126 on the proliferation and invasion ability of OSCC cells, 5-ethynyl-2′-deoxyuridine and Transwell assays were performed. The activities of MMP-2 and MMP-9 were evaluated via gelatin zymography. Our results showed that miRNA-126, which targets HIF-1α, enhances OSCC cell proliferation by regulating the cell cycle and reinforces the cell mobility of OSCC via HIF-1α expression. These findings suggest that miRNA-126 may be a novel marker for OSCC treatment and the development of new tools for patients with OSCC.

MicroRNAs (miRNAs) are a group of small non-coding RNAs consisting of 18~24 nucleotides in length. Each miRNA is expected to bind a few hundreds of putative target mRNAs, thus inhibiting their translation into protein products mostly by degradation of targets. With its biogenesis extensively deciphered, miRNAs have been implicated in a variety of biological processes, including early development and cellular metabolism. In addition, dysregulation of miRNAs and subsequent alterations in the expression of its target molecules are thought to be linked to the pathophysiology of multiple human illnesses, including cancer. To establish the miRNA-target relationships important for developing a specific disease, it is critical to validate the putative targets of each miRNA suggested by computational methods in vivo. In this review, we will first discuss oncogenic and tumor-suppressive roles of miRNAs in human cancer and introduce computational methods to predict putative targets of miRNAs. Then, the value of Drosophila melanogaster as an alternative model system will be further discussed in studying human cancer and in validating the miRNA-target relationships in vivo. Finally, we will present a possibility of applying the mammals-to-Drosophila-to-mammals approach to study the roles of miRNAs and their targets in the pathophysiology of oral cancer, an intractable type of cancer with poor prognosis and survival rate.

MicroRNA (miRNA, miR) is essential in regulating cell differentiation either by inhibiting mRNA translation or by inducing its degradation. However, the role of miRNA in odontoblastic cell differentiation is still unclear. In this study, we examined the molecular mechanism of miR-27-mediated regulation of odontoblast differentiation in MDPC-23 mouse odontoblastic cells derived from mouse dental papilla cells. The results of the present study demonstrated that the miR-27 expression increases significantly during MDPC-23 odontoblastic cell differentiation. Furthermore, miR-27 up-regulation promotes the differentiation of MDPC-23 cells and accelerates mineralization without cell proliferation. The over-expression of miR-27 significantly increased the expression levels of Wnt1 mRNA and protein. In addition, the results of target gene prediction revealed that Wnt1 mRNA has an miR-27 binding site in its 3’UTR, and is increased by miR-27. These results suggested that miR-27 promotes MDPC-23 odontoblastic cell differentiation by targeting Wnt1 signaling. Therefore, miR-27 is a critical odontoblastic differentiation molecular target for the development of miRNA based therapeutic agents in dental medicine.

MicroRNAs (miRNAs, miRs) are about 21-25 nucleotides in length and regulate mRNA translation by base pairing to partially complementary sites, predominantly in the 3’-untranslated region (3’-UTR) of the target mRNA. In this study, the expression profile of miRNAs was compared and analyzed for the establishment of miRNA-related odontoblast differentiation using MDPC-23 cells derived from mouse dental papilla cells. To determine the expression profile of miRNAs during the differentiation of MDPC-23 cells, we employed miRNA microarray analysis, quantitative real-time PCR (qRT-PCR) and Alizaline red-S staining. In the miRNA microarray analysis, 11 miRNAs were found to be up- or down-regulated more than 3-fold between day 0 (control) and day 5 of MDPC-23 cell differentiation among the 1,769 miRNAs examined. In qRT-PCR analysis, the expression levels of two of these molecules, miR-194 and miR-126, were increased and decreased in the control MDPC-23 cells compared with the MDPC-23 cells at day 5 of differentiation, respectively. Importantly, the overexpression of miR-194 significantly accelerated mineralization compared with the control cultures during the differentiation of MDPC-23 cells. These results suggest that the miR-194 augments MDPC-23 cell differentiation, and potently accelerates the mineralization process. Moreover, these in vitro results show that different miRNAs are deregulated during the differentiation of MDPC-23 cells, suggesting the involvement of these genes in the differentiation and mineralization of odontoblasts.

S-adenosylhomocysteine hydrolase-like protein 1 (AHCYL1), also known as IP3 receptor- binding protein released with IP3 (IRBIT), regulates IP3-induced Ca2+ release in the cytoplasm of cells and, therefore, is likely to be an important gene regulating various biological processes in the oviduct of chickens. However, the identification of the AHCYL1 gene in chickens has not been investigated. Therefore, the objectives of this study were to examine the tissue- and cell-specific expression of AHCYL1 gene in chicken organs, especially in reproductive organ, and determine functional actions of AHCYL1 in chicken oviduct development via estrogen. The results indicated that AHCYL1 mRNA is expressed in chicken reproductive organs and DES(diethylstilbesterol, a synthetic estrogen agonist) stimulates the cell specific expression of AHCYL1 in immature chicken oviduct. These results suggest that AHCYL1 is a novel estrogen-stimulated gene associated with development of the chicken oviduct. Next, in the present study, we show that inhibition of Erk1/2 can block DES-induced AHCYL1 expression. Also, we found that knockdown of AHCYL1 expression down-regulates expression of oviduct specific genes and AHCYL1 expression is regulated at the post-transcriptional level by specific miRNAs. These results strongly suggest that estrogen-mediated AHCYL1 gene expression plays a crucial role in growth, differentiation and function of the hen oviduct. Also, our results will be useful for understanding the fundamental mechanism(s) of estrogen action responsible for development of hen oviduct. This research was funded by the World Class University (WCU) program (R31-10056), Basic Science Research Program (2010-0013078) through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science, and Technology and by the Next-Generation BioGreen 21 Program (No.PJ008142), Rural Development Administration, Republic of Korea.

MicroRNAs (miRNAs) are small non-coding RNAs that mediate gene expression at the post-transcriptional level by degrading or repressing targeted mRNAs. These molecules are about 21-25 nucleotides in length and exert their effects by binding to partially complementary sites in mRNAs, predominantly in the 3'-untranslated region (3'-UTR). Recent evidence has demonstrated that miRNAs can function as oncogenes or tumor suppressors through the modulation of multiple oncogenic cellular processes in cancer development, including initiation, cell proliferation, apoptosis, invasion and metastasis. In our present study, we examined the expression profile of miRNAs related to oral cancer cell growth inhibition using normal human oral keratinocytes (NHOK) and YD-38 human oral cancer cells. By miRNA microassay analysis, 40 and 31 miRNAs among the 1,769 examined were found to be up- and down-regulated in YD-38 cells compared with NHOK cells, respectively. Using qRT-PCR analysis, the expression levels of miR-30a and miR-1246 were found to be increased in YD-38 cells compared with NHOK cells, whereas miR-203 and miR-125a were observed to be decreased. Importantly, the overexpression of miR-203 and miR-125a significantly inhibited the growth of YD-38 cells. This finding and the microarray data indicate the involvement of specific miRNAs in the development and progression of oral cancer.

Periodontitis results from the activation of host immune and inflammatory defense responses to subgingival plaque bacteria, most of which are gram-negative rods with lipopolysaccharides (LPSs) in their cell walls. LPSs have been known to induce proinflammatory responses and recently it was reported also that they induce the expression of microRNAs(miRNAs) in host cells. In our current study therefore, we aimed to examine and compare the miRNA expression patterns induced by the LPSs of major periodontopathogens in the human gingival epithelial cell line, Ca9-22. The cells were treated with 1 μg/ml of E. coli (Ec) LPS or 5 μg/ml of an LPS preparations from four periodontopathogens Porphyromonas gingivalis (Pg), Prevotella intermedia (Pi), Aggregatibacter actinomycetemcomitans (Aa), and Fusobacterium nucleatum (Fn) for 24 h. After small RNA extraction from the treated cells, miRNA microarray analysis was carried out and characteristic expression profiles were observed. Fn LPS most actively induced miRNAs related to inflammation, followed by Aa LPS, Pi LPS, and Ec LPS. In contrast, Pg LPS only weakly activated miRNAs related to inflammation. Among the miRNAs induced by each LPS, miR-875-3p, miR-449b, and miR-520d-3p were found to be commonly up-regulated by all five LPS preparations, although at different levels. When we further compared the miRNA expression patterns induced by each LPS, Ec LPS and Pi LPS were the most similar although Fn LPS and Aa LPS also induced a similar miRNA expression pattern. In contrast, the miRNA profile induced by Pg LPS was quite distinctive compared with the other bacteria. In conclusion, miR-875- 3p, miR-449b, and miR-520d-3p miRNAs are potential targets for the diagnosis and treatment of periodontal inflammation induced by subgingival plaque biofilms. Furthermore, the observations in our current study provide new insights into the inflammatory miRNA response to periodontitis.

MicroRNAs (miRNAs) are endogenous non-coding genes that participate in post-transcription regulation by either degrading mRNA or blocking its translation. It is considered to be very important in regulating insect development and metamorphosis. Insects are the largest group of animals and are extremely valuable in biological and agriculture research. Insects are also important pests to human health and agriculture, and efforts are necessary protect both humans and plants from disease and damage. Despite their importance, insects lag behind mammals, nematodes, and plants in miRNA research. At present, only 279 insect miRNAs have been identified from Drosophila melanogaster, Anopheles gambiae, Apis mellifera, Bombyx mori, and D. pseudoobscura in miRBase, and most of these miRNAs were computationally predicted without experimental validation. Functional analysis of insect miRNAs has only been conducted in D. melanogaster.

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.

DGCR8 is a RNA-binding protein working with DROSHA involved in critical processes for microRNA production in the nucleus. To understand function of miRNAs in the uterus, we have produced uterus-specific Dgcr8 conditional knock-out mice using two well-known Cre mouse models, anti-Mullerian hormone receptor 2 (Amhr2)-Cre and progesterone receptor (PR)-Cre. Dgcr8flox/flox;PRcre/+ mice were mainly analyzed and considered as uDgcr8 KO in this study unless otherwise indicated as Dgcr8flox/flox;Amhr2cre/+ mice. Morphological and histological analyses, embryo cultures, genomic DNA PCR, realtime RT-PCR and Western blotting were performed. uDgcr8 KO females bred with fertile males did not produce any offspring, suggesting that these mice are infertile. Vaginal smear analyses showed that these mice do not undergo estrous cycle, whereas Dgcr8flox/flox;Amhr2cre/+ mice exhibited regular estrous cyclicity. In vitro culture of 2-cell stage embryos and histological analyses for CL in uDgcr8 KO demonstrated that they can respond to gonadotrophins to ovulate healthy oocytes with comparable fertilization potentials as compared to those in Dgcr8flox/flox mice (Control). Gross morphology, histology, and weight of uteri of uDgcr8 KO mice were similar to those of control at 3-week-old stage. However, uterus become extremely thinner and shorter from 4-week-old stage onward. Histological examination showed significant reduction in gland numbers and stromal area from 4-week-old stage. Interestingly, this phenotype is reflected by significant increase of PR expression in the uteri of 4-week-old mice. In addition, stromal cell proliferation of uDgcr8 KO is severely impaired. BrdU incorporation experiments showed that while epithelial cells undergo proliferation by E2 treatment, stromal cells do not incorporate BrdU under the uterine conditions provided with E2+P4. Collectively, these results conclude that microRNAs are essential for uterine stromal cell proliferation in mice.

LincRNA (long intergenic noncoding RNA)란 단백질을 coding하지 않으며 genome 상의 intergenic region으로부터 전사되는 200 nucleotide 이상으로 이루어진 RNA를 총칭하는 용어이다. Whole-genome tiling array나 transcriptome sequencing 등에 의해 여러 모델 생물종에서 lincRNA의 존재가 확인되어 왔으며, 이들은 microRNA나 단백질과는 달리 매우 다양한 방식으로 유전자 발현을 조절하는 것으로 보인다. 최근 동물에서는 생물학적으로 중요한 의미를 가지는 몇몇 lincRNA가 발견되었고 이들이 세포 사멸‧세포 주기‧줄기 세포의 전분화능 등의 다양한 생물학적 과정에 관여할 것이라는 증거가 포착되었다. 이에 비하여 식물의 lincRNA에 대한 이해는 아직 초보적인 수준이다. 그러나 최근 들어 애기장대를 중심으로 최적 생장 조건에서와 각종 스트레스를 유도한 조건에서 lincRNA의 발현 양상을 비교함으로써 식물의 스트레스 저항성에 있어 lincRNA의 역할을 규명하려는 시도가 있어 왔다. 이들 연구에 의하면 한발‧냉해‧염해 등의 스트레스 조건 하에서 lincRNA의 pool에 상당한 변화가 일어나는 것으로 보인다. 이에 본 연구에서는 벼의 질소 결핍 스트레스 관련 lincRNA를 오믹스 기법을 이용한 대량 발굴 및 이에 대한 기능적 연구를 수행하고자 한다. 이를 위해 질소 결핍 조건에서 생장시킨 벼 샘플에 대해 RNA-Seq을 실시하였으며, 이에 대한 분석을 통해 질소 결핍 스트레스에 반응하는 다수의 질소 대사 관련 유전자, microRNA 및 lincRNA 후보들을 선정하였다. 앞으로는 qRT-PCR 등의 기법을 통해 lincRNA의 발현 및 기능에 대한 추가적인 연구를 진행함으로써 이들이 질소 결핍 스트레스에 대한 벼의 반응과 어떻게 연관되어 있는지를 확인할 것이다.