Identification Of microRNAs Research Articles

MicroRNA-202-5p-dependent inhibition of Bcl-2 contributes to macrophage apoptosis and atherosclerotic plaque formation

BackgroundThe identification of microRNA (miRNA)-related molecular mechanisms has advanced the development of new therapeutics for atherosclerosis (AS). The roles of miR-202-5p- in the pathogenic mechanisms of AS have not been explored. MethodsMacrophages were transfected with a series of miR-202-5p mimic/inhibitor, and then assessed for changes in viability, apoptosis, and secretion of inflammatory cytokines. The regulatory mechanism of miR-202-5p was explored through dual-luciferase reporter gene assay. A mouse model of AS was developed in ApoE-/- mice fed with high-fat diet to examine the in vivo effects of miR-202-5p on atherosclerotic plaque formation, collagen synthesis, and fiber cap thickness. ResultsElevated miR-202-5p was found in atherosclerotic plaque tissues of the mice. miR-202-5p was able to induce macrophage apoptosis and release of pro-inflammatory factors. Besides, miR-202-5p limited Bcl-2 expression and elevated the levels of Bax, cleaved caspase-3, and cleaved caspase-9. Bcl-2 was concluded as a target gene of miR-202-5p. The pro-apoptotic effect of miR-202-5p on macrophages was achieved via limiting Bcl-2. In the mouse AS model, restoration of miR-202-5p stimulated atherosclerotic plaque formation, but reduced collagen synthesis and fiber cap thickness. ConclusionThese data collectively suggest a pro-apoptotic action of miR-202-5p in macrophages that contributes to atherosclerotic plaque formation.

Identification and characterization of immune-related microRNAs in hybrid snakehead(Channa maculata♀ × Channa argus♂)after treated by Echinacea purpurea (Linn.) Moench

Echinacea purpurea (Linn.) Moench (EP) is a globally popular herbal medicine, which showed effects on growth promotion, antioxidant and immunomodulatory activities in fish culture world widely. However, there are few studies about the effects on miRNAs by EP in fish. The hybrid snakehead fish (Channa maculate♀ × Channa argus ♂) was new important economic specie of freshwater aquaculture in China with high market value and demand while there were only a few reports about its miRNAs. To overview immune-related miRNAs of the hybrid snakehead fish and to further understand the immune regulating mechanism of EP, we herein constructed and analyzed three small RNA libraries of immune tissues including liver, spleen and head kidney of the fish with or without EP treatment via Illumina high-throughput sequencing technology. Results showed that EP can affect the immune activities of fish by the miRNA-regulated ways. Totally, 67 (47 up and 20 down) miRNAs in liver, 138 (55 up and 83 down) miRNAs in spleen, and 251 (15 up and 236 down) miRNAs in spleen were detected, as well as 30, 60, 139 kinds of immune-related miRNAs belonging to 22, 35 and 66 families of the three tissues respectively. The expressions of 8 immune-related miRNA family members were found in all the three tissues, including miR-10, miR-133, miR-22 and etc. Some miRNAs have been identified involved in the innate and adaptive immune responses, such as the miR-125, miR-138, and miR-181 family. Ten miRNA families with antioxidant target genes were also discovered, including miR-125, miR-1306, and miR-138, etc. Results from Gene Ontology (GO) and KEGG pathway analysis further confirmed there are a majority immune response targets of the miRNAs involved in the EP treatment process. Our study deepened understanding roles of miRNAs in fish immune system and provides new ideas for the study of immune mechanism of EP.

Identification and profiling of microRNAs during yak’s testicular development

BackgroundNormal testicular development is highly crucial for male reproduction and is a precondition for spermatogenesis that is the production of spermatozoa in the testes. MiRNAs have been implicated in several testicular biological processes, including cell proliferation, spermatogenesis, hormone secretion, metabolism and reproductive regulation. In the present study, we used deep sequencing data to study the functions of miRNAs during testicular development and spermatogenesis, by analyzing the expression patterns of small RNAs in 6-, 18- and 30-month-old yak testis tissues.ResultsA total of 737 known and 359 novel miRNAs were obtained from 6-, 18- and 30-month-old yak testes. In all, we obtained 12, 142 and 139 differentially expressed (DE) miRNAs in 30- vs. 18-, 18- vs. 6-, and 30- vs. 6-month-old testes, respectively. Gene Ontology (GO) annotation and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis of all DE miRNA target genes revealed BMP2, TGFB2, GDF6, SMAD6, TGFBR2 and other target genes as participants in different biological processes, including TGF-β, GnRH, Wnt, PI3K–Akt, MAPK signaling pathways and several other reproductive pathways. In addition, quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR) was used to detect the expression of seven randomly selected miRNAs in 6-, 18- and 30-month-old testes, and the results were consistent with the sequencing data.ConclusionsThe differential expression of miRNAs in yak testes at different development stages was characterized and investigated using deep sequencing technology. We believe that the results will contribute to further understanding the functions of miRNAs in regulating the development of yak testes and improving the reproductive performance of male yaks.

Identification of Key MicroRNAs and Genes between Colorectal Adenoma and Colorectal Cancer via Deep Learning on GEO Databases and Bioinformatics.

Deep learning techniques are gaining momentum in medical research. Colorectal adenoma (CRA) is a precancerous lesion that may develop into colorectal cancer (CRC) and its etiology and pathogenesis are unclear. This study aims to identify transcriptome differences between CRA and CRC via deep learning on Gene Expression Omnibus (GEO) databases and bioinformatics in the Chinese population. In this study, three microarray datasets from the GEO database were used to identify the differentially expressed genes (DEGs) and differentially expressed miRNAs (DEMs) in CRA and CRC. The FunRich software was performed to predict the targeted mRNAs of DEMs. The targeted mRNAs were overlapped with DEGs to determine the key DEGs. Molecular mechanisms of CRA and CRC were evaluated using enrichment analysis. Cytoscape was used to construct protein-protein interaction (PPI) and miRNA-mRNA regulatory networks. We analyzed the expression of key DEMs and DEGs, their prognosis, and correlation with immune infiltration based on the Kaplan-Meier plotter, UALCAN, and TIMER databases. A total of 38 DEGs are obtained after the intersection, including 11 upregulated genes and 27 downregulated genes. The DEGs were involved in the pathways, including epithelial-to-mesenchymal transition, sphingolipid metabolism, and intrinsic pathway for apoptosis. The expression of has-miR-34c (P = 0.036), hsa-miR-320a (P = 0.045), and has-miR-338 (P = 0.0063) was correlated with the prognosis of CRC patients. The expression levels of BCL2, PPM1L, ARHGAP44, and PRKACB in CRC tissues were significantly lower than normal tissues (P < 0.001), while the expression levels of TPD52L2 and WNK4 in CRC tissues were significantly higher than normal tissues (P < 0.01). These key genes are significantly associated with the immune infiltration of CRC. This preliminary study will help identify patients with CRA and early CRC and establish prevention and monitoring strategies to reduce the incidence of CRC.

Electrical detection and analysis of exosomes by a glass capillary nanopore.

An exosome is a vesicle less than 200 nm in diameter released from a cell and works as a medium for cell-to-cell communication. It is suggested that compositions of encapsulated molecules in exosomes have diversity even from a same cell. Single-particle analysis will be insight into the understanding the diversity, but it is still challenging. Nanopore technology will have a potential to detect and to capture single exosomes because it can discriminate nanoparticle properties including size, shape, and surface properties such as the charge by observation of ionic current change through a nano-sized pore. Here, we proposed to use a glass capillary nanopore (φ∼200 nm) and attempt to capture milk exosomes. Exosomes used in this study were extracted from cow milk using a procedure proposed previously. The particle sizes were confirmed by dynamic light scattering (DLS). A glass capillary nanopore was prepared by a puller. We observed the pore diameter of the capillaries by a scanning electron microscope (SEM). In the nanopore experiments, a glass capillary was filled with and immersed in PBS solution to measure I-V curve for checking the pore conductance, and then it was replaced in the exosome solution to detect the exosomes. The size of extracted exosomes was confirmed by DLS, and it was consistent with that in a previous study (∼130 nm). The outer diameter of the glass nanopores ranged from about 100 to 500 nm determined by SEM observation. For channel current measurement, the current blockages were observed in the presence of exosomes that was depended on the polarity of the applying voltages. We are conducting identification of microRNA encapsulated in exosomes collected from the nanopore by RT-qPCR, and it will be discussed in San Diego.

In silico identification of microRNAs targeting the PPARα/γ: promising therapeutics for SARS-CoV‑2 infection

ABSTRACT The SARS-CoV-2 lifecycle is dependent on the host metabolism machinery. It upregulates the PPARα and PPARγ genes in lipid metabolism, which supports the essential viral replication complex including lipid rafts and palmitoylation of viral protein. The use of PPAR ligands in SARS-CoV-2 infection may have positive effects by preventing cytokine storm and the ensuing inflammatory cascade. The inhibition of PPARα and PPARγ genes may alter the metabolism and may disrupt the lifecycle of SARS-CoV-2 and COVID-19 progression. In the present work, we have identified possible miRNAs targeting PPARα and PPARγ in search of modulators of PPARα and PPARγ genes expression. The identified miRNAs could possibly be viewed as new therapeutic targets against COVID-19 infection.

Genome-wide analysis and identification of microRNAs in Medicago truncatula under aluminum stress.

Numerous studies have shown that plant microRNAs (miRNAs) play key roles in plant growth and development, as well as in response to biotic and abiotic stresses; however, the role of miRNA in legumes under aluminum (Al) stress have rarely been reported. Therefore, here, we aimed to investigate the role of miRNAs in and their mechanism of Al tolerance in legumes. To this end, we sequenced a 12-strand-specific library of Medicago truncatula under Al stress. A total of 195.80 M clean reads were obtained, and 876 miRNAs were identified, of which, 673 were known miRNAs and 203 were unknown. A total of 55 miRNAs and their corresponding 2,502 target genes were differentially expressed at various time points during Al stress. Further analysis revealed that mtr-miR156g-3p was the only miRNA that was significantly upregulated at all time points under Al stress and could directly regulate the expression of genes associated with root cell growth. Three miRNAs, novel_miR_135, novel_miR_182, and novel_miR_36, simultaneously regulated the expression of four Al-tolerant transcription factors, GRAS, MYB, WRKY, and bHLH, at an early stage of Al stress, indicating a response to Al stress. In addition, legume-specific miR2119 and miR5213 were involved in the tolerance mechanism to Al stress by regulating F-box proteins that have protective effects against stress. Our results contribute to an improved understanding of the role of miRNAs in Al stress in legumes and provide a basis for studying the molecular mechanisms of Al stress regulation.

Identification and analysis of key microRNAs derived from osteoarthritis synovial fluid exosomes.

Identification and analysis of key microRNAs derived from osteoarthritis synovial fluid exosomes.

MicroRNA Identification, Target Prediction, and Validation for Crop Improvement.

Micro-RNAs (mi-RNAs) are regulatory elements that play a vital role in the growth, development, and metabolic regulation of plants. In current research, the isolation of miRNAs is a tedious and difficult task using in vitro methods. However, recent exploration into the remarkably highly conserved nature of nucleotide sequences of miRNAs assists in the identification of miRNAs in plant species through homologous approaches. Here, we describe the in silico-based method for identification of miRNAs from the EST database which is emerging as a faster and more reliable approach along with the development of miRNA-SSR markers. This approach has the potential to accelerate research into the regulation of gene expression in various plant species such as tea, potato, tomato, tobacco, and orphan crops like cluster bean.

Identification of key microRNAs regulating ELOVL6 and glioblastoma tumorigenesis

ELOVL fatty acid elongase 6 (ELOVL6) controls cellular fatty acid (FA) composition by catalyzing the elongation of palmitate (C16:0) to stearate (C18:0) and palmitoleate (C16:1n-7) to vaccinate (C18:1n-7). Although the transcriptional regulation of ELOVL6 has been well studied, the post-transcriptional regulation of ELOVL6 is not fully understood. Therefore, this study aims to evaluate the role of microRNAs (miRNAs) in regulating human ELOVL6. Bioinformatic analysis identified five putative miRNAs: miR-135b-5p, miR-135a-5p, miR-125a-5p, miR-125b-5p, and miR-22–3p, which potentially bind ELOVL6 3′-untranslated region (UTR). Results from dual-luciferase assays revealed that these miRNAs downregulate ELOVL6 by directly interacting with the 3′-UTR of ELOVL6 mRNA. Moreover, miR-135b-5p and miR-135a-5p suppress cell proliferation and migration in glioblastoma multiforme cells by inhibiting ELOVL6 at the mRNA and protein levels. Taken together, our results provide novel regulatory mechanisms for ELOVL6 at the post-transcriptional level and identify potential candidates for the treatment of patients with glioblastoma multiforme.

Differential Effects of Somatostatin, Octreotide, and Lanreotide on Neuroendocrine Differentiation and Proliferation in Established and Primary NET Cell Lines: Possible Crosstalk with TGF-β Signaling.

GEP-NETs are heterogeneous tumors originating from the pancreas (panNET) or the intestinal tract. Only a few patients with NETs are amenable to curative tumor resection, and for most patients, only palliative treatments to successfully control the disease or manage symptoms remain, such as with synthetic somatostatin (SST) analogs (SSAs), such as octreotide (OCT) or lanreotide (LAN). However, even cells expressing low levels of SST receptors (SSTRs) may exhibit significant responses to OCT, which suggests the possibility that SSAs signal through alternative mechanisms, e.g., transforming growth factor (TGF)-β. This signaling mode has been demonstrated in the established panNET line BON but not yet in other permanent (i.e., QGP) or primary (i.e., NT-3) panNET-derived cells. Here, we performed qPCR, immunoblot analyses, and cell counting assays to assess the effects of SST, OCT, LAN, and TGF-β1 on neuroendocrine marker expression and cell proliferation in NT-3, QGP, and BON cells. SST and SSAs were found to regulate a set of neuroendocrine genes in all three cell lines, with the effects of SST, mainly LAN, often differing from those of OCT. However, unlike NT-3 cells, BON cells failed to respond to OCT with growth arrest but paradoxically exhibited a growth-stimulatory effect after treatment with LAN. As previously shown for BON, NT-3 cells responded to TGF-β1 treatment with induction of expression of SST and SSTR2/5. Of note, the ability of NT-3 cells to respond to TGF-β1 with upregulation of the established TGF-β target gene SERPINE1 depended on cellular adherence to a collagen-coated matrix. Moreover, when applied to NT-3 cells for an extended period, i.e., 14 days, TGF-β1 induced growth suppression as shown earlier for BON cells. Finally, next-generation sequencing-based identification of microRNAs (miRNAs) in BON and NT-3 revealed that SST and OCT impact positively or negatively on the regulation of specific miRNAs. Our results suggest that primary panNET cells, such as NT-3, respond similarly as BON cells to SST, SSA, and TGF-β treatment and thus provide circumstantial evidence that crosstalk of SST and TGF-β signaling is not confined to BON cells but is a general feature of panNETs.

Identification of microRNA and analysis of target genes in Panax ginseng

ObjectiveGinsenosides, polysaccharides and phenols, the main active ingredients in Panax ginseng, are not different significantly in content between 3 and 5 years old of ginsengs called Yuan ginseng and more than ten years old ones called Shizhu ginseng. The responsible chemical compounds cannot fully explain difference in efficacy between them. According to reports in Lonicerae Japonicae Flos (Jinyinhua in Chinese) and Glycyrrhizae Radix et Rhizoma (Gancao in Chinese), microRNA may play a role in efficacy, so we identified microRNAs in P. ginseng at the different growth years and analyzed their target genes. MethodsUsing high-throughput sequencing, the RNA-Seq, small RNA-Seq and degradome databases of P. ginseng were constructed. The differentially expressed microRNAs was identified by qRT-PCR. ResultsA total of 63,875 unigenes and 24,154,579 small RNA clean reads were obtained from the roots of P. ginseng. From these small RNAs, 71 miRNA families were identified by bioinformatics target prediction software, including 34 conserved miRNAs, 37 non-conserved miRNA families, as well as 179 target genes of 17 known miRNAs. Through degradome sequencing and computation, we finally verified 13 targets of eight miRNAs involved in transcription, energy metabolism, biological stress and disease resistance, suggesting the significance of miRNAs in the development of P. ginseng. Consistently, major miRNA targets exhibited tissue specificity and complexity in expression patterns. ConclusionDifferential expression microRNAs were found in different growth years of ginsengs (Shizhu ginseng and Yuan ginseng), and the regulatory roles and functional annotations of miRNA targets in P. ginseng need further investigation.

MiRNA Signature in CSF From Patients With Primary Progressive Multiple Sclerosis.

Primary progressive multiple sclerosis (PPMS) displays a highly variable disease progression with a characteristic accumulation of disability, what makes difficult its diagnosis and efficient treatment. The identification of microRNAs (miRNAs)-based signature for the early detection in biological fluids could reveal promising biomarkers to provide new insights into defining MS clinical subtypes and potential therapeutic strategies. The objective of this cross-sectional study was to describe PPMS miRNA profiles in CSF and serum samples compared with other neurologic disease individuals (OND) and relapsing-remitting MS (RRMS). First, a screening stage analyzing multiple miRNAs in few samples using OpenArray plates was performed. Second, individual quantitative polymerase chain reactions (qPCRs) were used to validate specific miRNAs in a greater number of samples. A specific profile of dysregulated circulating miRNAs (let-7b-5p and miR-143-3p) was found downregulated in PPMS CSF samples compared with OND. In addition, in serum samples, miR-20a-5p and miR-320b were dysregulated in PPMS against RRMS and OND, miR-26a-5p and miR-485-3p were downregulated in PPMS vs RRMS, and miR-142-5p was upregulated in RRMS compared with OND. We described a 2-miRNA signature in CSF of PPMS individuals and several dysregulated miRNAs in serum from patients with MS, which could be considered valuable candidates to be further studied to unravel their actual role in MS. This study provides Class II evidence that specific miRNA profiles accurately distinguish PPMS from RRMS and other neurologic disorders.

Identification of serum micro-RNAs of early knee osteoarthritis in a cohort of Egyptian patients

ABSTRACT Background Osteoarthritis (OA), is a prevalent low-grade inflammatory synovial joint disease characterized by progressive cartilage degradation and alteration of the entire joint. Knee OA (KOA) is the commonest form of OA. Osteoarthritis is the 4th leading cause of disability worldwide with no cure and therefore identifying persons with early OA of the knee (KOA), is important to retard progression of the disease process. Several proinflammatory cytokines and microRNAs (miRNAs) are involved in OA pathogenesis. Objective The aim of the work was to investigate the serum miRNA-136 (miR-136) and miR-155-5p expression profile, IL-8 and IL-17 levels in subjects with early KOA and to further evaluate and compare the expression profile of these miRNAs, and level of serum IL-8 and IL-17 in subjects with early and severe KOA. Methods Serum miR-136 and miR-155-5p expression profile in 40 patients with early KOA were compared to 40 age and sex matched healthy controls and 10 patients with severe KOA. Clinical, laboratory, and disease parameters were assessed. Serum and synovial fluid miRNAs were assessed by real-time polymerase chain reaction. Levels of IL-17 and IL-8 levels were determined by the enzyme linked immunosorbent assay test. Results miR-155-5p in serum was significantly higher in early KOA patients compared to healthy controls and to patients with severe OA. Synovial miRNA-155-5p expression levels were significantly higher than serum miRNA-155-5p in severe KOA patients compared to early OA patients. When we compared the expression levels of miRNA-136 between cases and healthy controls, there was no statistical significant difference, p=0.413. Serum IL-8 levels were significantly higher in early OA patients compared to healthy controls. Conclusions Serum miR-155-5p and IL-8 levels are potential useful biomarkers for the early detection of OA and in particular, early KOA.

149 Identification of microRNAs associated with bovine

Reproduction, Fertility and Development is an international journal publishing original research , review and comment in the fields of reproduction and developmental biology in humans, domestic animals and wildlife

The Identification and Analysis of MicroRNAs Combined Biomarkers for Hepatocellular Carcinoma Diagnosis.

Hepatocellular carcinoma (HCC) is a common malignant tumor with high morbidity and mortality globally. Compared with traditional diagnostic methods, microRNAs (miRNAs) are novel biomarkers with higher accuracy. We aimed to identify combinatorial biomarkers of miRNAs to construct a classification model for the diagnosis of HCC. The mature miRNA expression profile data of six cancers (liver, lung, gastric, breast, prostate, and colon) were retrieved from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) database with accession number GSE36915, GSE29250, GSE99417, GSE41970, GSE64333 and GSE35982. The messenger RNA (mRNA) expression profile data of these six cancers were obtained from TCGA. Three R software packages, student's t-test, and a normalized foldchange method were utilized to identify HCC-specific differentially expressed miRNAs (DEMs). Using all combinations of obtained HCC-specific DEMs as input features, we constructed a classification model by support vector machine searching for the optimal combination. Furthermore, target genes prediction was conducted on the miRWalk 2.0 website to obtain differentially expressed mRNAs (DEmRNAs), and KEGG pathway enrichment was analyzed on the DAVID website. The optimal combination consisted of four miRNAs (hsa-miR-130a-3p, hsa-miR-450b-5p, hsa-miR-136-5p, and hsa-miR-24-1-5p), of which the last one has not been currently reported to be relevant to HCC. The target genes of hsa-miR-24-1-5p (CDC7, ACACA, CTNNA1, and NF2) were involved in the cell cycle, AMPK signaling pathway, Hippo signaling pathway, and insulin signaling pathway, which affect the proliferation, metastasis, and apoptosis of cancer cells. Moreover, the area under the receiver operating characteristic curves of the four miRNAs were all higher than 0.85. These results suggest that the miRNAs combined biomarkers were reliable for the diagnosis of HCC. Hsa-miR-24-1-5p was a novel biomarker for HCC diagnosis identified in this study.

Plant MicroRNA Identification and Annotation Using Deep Sequencing Data.

MicroRNAs (miRNAs) are endogenous non-coding small RNAs, which regulate gene expression at the post-transcriptional level. A large number of studies have revealed that they play key roles in diverse life activities, such as growth and development. In the last decade, deep sequencing technology has generated substantial small RNA sequencing (sRNA-Seq) data. Meanwhile, numerous tools have been developed to identify miRNAs from these sRNA-Seq data, resulting in a surge of miRNA annotations. Among these tools, the series of miRDeep-P and miRDeep-P2 have been widely used in plant miRNA annotation. Here, we employed miRDeep-P2 to demonstrate the plant miRNA annotation processes step by step using the deep sequencing data.

Identification of Novel miRNAs Involved in Cancer Progression and Metastasis in Clear Cell Renal Cell Carcinoma

MicroRNAs are non-coding molecules 21–23 nucleotides long that are involved in post-transcriptional regulation of gene expression by mRNA silencing. There is evidence that miRNA activity is associated with various types of human cancer, such as breast cancer, colorectal cancer, ovarian cancer and hepatocellular carcinoma, as well as with clear cell renal cell carcinoma. In 2020, the incidence of kidney cancer worldwide was 319,016. Clear cell renal cell carcinoma is associated with loss or mutation of the VHL gene. The aim of this study was to identify miRNAs that are expressed differently in samples of normal kidney tissue and tissue affected by clear cell renal cell carcinoma. For this study, a public miRNA dataset from ArrayExpress was obtained and post-processed. Mapping, identification of known and new microRNAs, and quantification were performed using the miRDeep2 computer program from the DESeq R/Bioconductor package. We performed target identification and functional load analysis using GeneCodis4. A total of 2656 miRNAs were found to be differentially expressed, of which 229 miRNAs were overexpressed and 302 were underexpressed. In this study, we identified five miRNAs that were already known from the literature to be significantly associated with clear cell renal cell carcinoma. In addition, we found a set of five microRNAs that had not previously associated with clear cell renal cell carcinoma.

Identification and Analysis of MicroRNAs Related to Double-Сolor Formation in Paeonia suffruticosa ‘Er Qiao’

Identification and Analysis of MicroRNAs Related to Double-Сolor Formation in Paeonia suffruticosa ‘Er Qiao’

Identification of Species-Specific MicroRNAs Provides Insights into Dynamic Evolution of MicroRNAs in Plants.

MicroRNAs (miRNAs) are an important class of regulatory small RNAs that program gene expression, mainly at the post-transcriptional level. Although sporadic examples of species-specific miRNAs (termed SS-miRNAs) have been reported, a genome-scale study across a variety of distant species has not been assessed. Here, by comprehensively analyzing miRNAs in 81 plant species phylogenetically ranging from chlorophytes to angiosperms, we identified 8048 species-specific miRNAs from 5499 families, representing over 61.2% of the miRNA families in the examined species. An analysis of the conservation from different taxonomic levels supported the high turnover rate of SS-miRNAs, even over short evolutionary distances. A comparison of the intrinsic features between SS-miRNAs and NSS-miRNAs (non-species-specific miRNAs) indicated that the AU content of mature miRNAs was the most striking difference. Our data further illustrated a significant bias of the genomic coordinates towards SS-miRNAs lying close to or within genes. By analyzing the 125,267 putative target genes for the 7966 miRNAs, we found the preferentially regulated functions of SS-miRNAs related to diverse metabolic processes. Collectively, these findings underscore the dynamic evolution of miRNAs in the species-specific lineages.