Characterization and comparative profiling of MicroRNAs in a sexual dimorphism insect, Eupolyphaga sinensis Walker

Disruption of microRNA pathway core genes inhibits molting and reproduction of the cigarette beetle, Lasioderma serricorne

BACKGROUND

MicroRNA (miRNA) pathway genes have been widely reported to participate in several physiological events in insect lifecycles. The cigarette beetle Lasioderma serricorne is an economically important storage pest worldwide. However, the functions of miRNA pathway genes in L. serricorne remain to be clarified. Herein, we investigated the function of molting and reproduction of the miRNA pathway in L. serricorne.

RESULTS

LsDicer-1, LsArgonaute-1, LsLoquacious and LsExportin-5 were universally expressed in adults, whereas LsPasha and LsDrosha were mainly expressed in the pupae. The genes presented different patterns in various tissues. Silencing of LsDicer-1, LsArgonaute-1, LsDrosha and LsExportin-5 resulted in a high proportion of wing deformities and molting defects. Silencing of LsDicer-1, LsArgonaute-1, LsPasha and LsLoquacious affected the development of the ovary and the maturation of oocytes, resulting in a significant decrease in fecundity. Further investigation revealed that the decreases in LsDicer-1 and LsArgonaute-1 expression destroyed follicular epithelia and delayed vitellogenesis and oocyte development. In addition, the expression levels of several miRNAs (let-7, let-7-5p, miR-8-3p, miR-8-5p, miR-9c-5p, miR-71, miR-252-5p, miR-277-3p, miR-263b and Novel-miR-50) were decreased significantly after knockdown of these miRNA pathway core genes, indicating that they played important roles in regulating miRNA-mediated gene expression.

CONCLUSION

The results indicate that miRNA pathway genes play important roles in the molting, ovarian development and female fecundity of L. serricorne, and thus are potentially suitable target genes for developing an RNAi strategy against a major pest of stored products. © 2024 Society of Chemical Industry.

The miR-184-3p promotes rice black-streaked dwarf virus infection by suppressing Ken in Laodelphax striatellus (Fallén)

BACKGROUND

MicroRNAs (miRNAs) play a key role in various biological processes by influencing the translation of target messenger RNAs (mRNAs) through post-transcriptional regulation. The miR-184-3p has been identified as an abundant conserved miRNA in insects. However, less is known about its functions in insect-plant virus interactions.

RESULTS

The function of miR-184-3p in regulation of plant viral infection in insects was investigated using a rice black-streaked dwarf virus (RBSDV) and Laodelphax striatellus (Fallén) interaction system. We found that the expression of miR-184-3p increased in L. striatellus after RBSDV infection. Injection of miR-184-3p mimics increased RBSDV accumulation, while treatment with miR-184-3p antagomirs inhibits the viral accumulation in L. striatellus. Ken, a zinc finger protein, was identified as a target of miR-184-3p. Knockdown of Ken increased the virus accumulation and promoted RBSDV transmission by L. striatellus.

CONCLUSION

This study demonstrates that RBSDV infection induces the expression of miR-184-3p in its insect vector L. striatellus. The miR-184-3p targets Ken to promote RBSDV accumulation and transmission. These findings provide a new insight into the function of the miRNAs in regulating plant viral infection in its insect vector. © 2023 Society of Chemical Industry.

TEP SNORD12B, SNORA63, and SNORD14E as novel biomarkers for hepatitis B virus-related hepatocellular carcinoma (HBV-related HCC)

PURPOSE

The alterations of RNA profile in tumor-educated platelets (TEPs) have been described as a novel biosource for cancer diagnostics. This study aimed to explore the potential snoRNAs in TEP as biomarkers for diagnostics of hepatitis B virus-related hepatocellular carcinoma (HBV-related HCC).

METHODS

Platelets were isolated using low-speed centrifugation and subjected to a quantitative polymerase chain reaction (qPCR) for snoRNAs detection.

RESULTS

Down-regulated SNORD12B and SNORD14E as well as up-regulated SNORA63 were identified in TEP from HBV-related HCC, which could act as diagnostic biomarkers for HBV-related HCC as well as the early disease. Besides, TEP SNORD12B, SNORD14E, and SNORA63 facilitate the diagnostic performance of AFP and achieve favorable diagnostics efficiency for HBV-related HCC when combined with platelet parameters.

CONCLUSIONS

Aberrant expression of SNORD12B, SNORA63, and SNORD14E in TEPs could serve as the novel and non-invasive biomarkers for HBV-related HCC diagnosis.

LncRNA MCM3AP-AS1 is downregulated in diabetic retinopathy and promotes cell apoptosis by regulating miR-211/SIRT1

AIM

This study aimed to investigate the role of lncRNA MCM3AP-AS1 in diabetic retinopathy (DR).

METHODS

Plasma MCM3AP-AS1 levels in DR patients (n = 80), T2DM patients (n = 80), and Controls (n = 80) were measured by qPCR and compared using ANOVA (one-way) and Tukey test. The expressions of lncRNA MCM3AP-AS1 and miR-211 in Human retinal pigment epithelial cells (hRPE) line ARPE-19 were detected by RT-qPCR. Western blot and annexin V-FITC staining were performed to investigate the role of MCM3AP-AS1/SIRT1 in ARPE-19 cell proliferation and apoptosis in vitro.

RESULTS

We observed that MCM3AP-AS1 was downregulated in DR patients 25 comparing to T2D patients without significantly complications. Bioinformatics analysis showed that MCM3AP-AS1 might bind miR-211. However, no significant correlation between these two factors was observed in DR patients. Consistently, overexpression of MCM3AP-AS1 and miR-211 failed to affect the expression of each other in hRPE. Interestingly, MCM3AP-AS1 overexpression upregulated SIRT1, a target of miR-211. Moreover, MCM3AP-AS1 was downregulated in DR patients compared to type 2 diabetic mellitus patients without significant complications. In RPEs, high glucose treatment downregulated MCM3AP-AS1. Cell apoptosis analysis showed that MCM3AP-AS1 and SIRT1 overexpression decreased the apoptotic rate of RPEs, and miR-211 overexpression reduced the effect of MCM3AP-AS1 and SIRT1 overexpression.

CONCLUSION

MCM3AP-AS1 is downregulated in DR and promotes cell apoptosis by regulating miR-211/SIRT1.

A Polysaccharide From Eupolyphaga sinensis Walker With Anti-HBV Activities In Vitro and In Vivo

Hepatitis B virus (HBV) infection remains a major global threat to human health worldwide. Recently, the Chinese medicines with antiviral properties and low toxicity have been a concern. In our previous study, Eupolyphaga sinensis Walker polysaccharide (ESPS) has been isolated and characterized, while its antiviral effect on HBV remained unclear. The anti-HBV activity of ESPS and its regulatory pathway were investigated in vitro and in vivo. The results showed that ESPS significantly inhibited the production of HBsAg, HBeAg, and HBV DNA in the supernatants of HepG2.2.15 in a dose-dependent manner; HBV RNA and core protein expression were also decreased by ESPS. The in vivo studies using HBV transgenic mice further revealed that ESPS (20 and 40 mg/kg/2 days) significantly reduced the levels HBsAg, HBeAg, and HBV DNA in the serum, as well as HBV DNA and HBV RNA in mice liver. In addition, ESPS activated the Toll-like receptor 4 (TLR4) pathway; elevated levels of IFN-β, TNF-α, and IL-6 in the serum were observed, indicating that the anti-HBV effect of ESPS was achieved by potentiating innate immunity function. In conclusion, our study shows that ESPS is a potential anti-HBV ingredient and is of great value in the development of new anti-HBV drugs.

Sex-Biased Gene Expression of Mesobuthus martensii Collected from Gansu Province, China, Reveals Their Different Therapeutic Potentials

The scorpions, named Mesobuthus martensii, commonly called Quanxie (全蝎) in Chinese, have been widely used as one of the animal medicines for more than 1,000 years because of the strong toxicity of their venoms. Meanwhile, scorpions are sexually dimorphic in appearance, and many exhibit traits associated with sex-biased gene expression, including maternal care, mating competition, female mating choices, ecology, and even venom composition and lethality. This study aims to explore the differences in composition of the venom of scorpions of different sex using the method of transcriptomics. Whole de novo transcriptomes were performed on the samples of M. martensii captured from Gansu Province to identify their sex-biased gene expression. The conserved CO-1 sequences of the captured samples matched that of M. martensii. A total of 8,444 (35.15%), 7,636 (31.78%), 8,510 (35.42%), 7,840 (32.63%), 9,980 (41.54%), and 11,829 (49.23%) unigenes were annotated with GO, KEGG, Pfam, Swissprot, eggNOG, and NR databases. Moreover, a total of 43 metalloproteases, 40 potassium channel toxins, 24 phospholipases, 12 defensins, 10 peroxiredoxins, 9 cysteine proteinase inhibitors, 7 serine protease inhibitors, 6 sodium channel toxins, 2 NDBPs, 1 calcium channel toxin, 1 waprin-like peptide, 1 antibacterial peptide, 1 antimicrobial peptide, and 1 anticoagulant peptide were screened out. With the fold change of 2 and 0.5, p value < 0.01, and q value < 0.05 as thresholds, a total of 41 out of 157 (26.11%) toxin-related unigenes had significant differential expression, and this ratio was much higher than the ratio of differentially expressed unigenes out of all annotated ones (8.84%). Of these differentially expressed toxins, 28 were upregulated and occupied the majority, up to 68.30%. The female scorpions showed more upregulated unigenes that annotated with toxins and had the potential to be used as more effective therapeutic drugs. In addition, this method of omics can be further used as a useful way to identify the difference between female and male toxic animals.

miRNAs of Aedes aegypti (Linnaeus 1762) conserved in six orders of the class Insecta

Aedes aegypti L. is the most important vector of arboviruses such as dengue, Zika, chikungunya, Mayaro, and yellow fever, which impact millions of people's health per year. MicroRNA profile has been described in some mosquito species as being important for biological processes such as digestion of blood, oviposition, sexual differentiation, insecticide resistance, and pathogens dissemination. We identified the miRNAs of Ae. aegypti females, males and eggs of a reference insecticide susceptible strain New Orleans and compared them with those other insects to determine miRNA fingerprint by new-generation sequencing. The sequences were analyzed using data mining tools and categorization, followed by differential expression analysis and conservation with other insects. A total of 55 conserved miRNAs were identified, of which 34 were of holometabolous insects and 21 shared with hemimetabolous insects. Of these miRNAs, 32 had differential expression within the stages analyzed. Three predominant functions of miRNA were related to embryonic development regulation, metamorphosis, and basal functions. The findings of this research describe new information on Ae. aegypti physiology which could be useful for the development of new control strategies, particularly in mosquito development and metamorphosis processes.

A Day in the Life: Identification of Developmentally Regulated MicroRNAs in the Colorado Potato Beetle (Leptinotarsa decemlineata; Coleoptera: Chrysomelidae)

The Colorado potato beetle (Leptinotarsa decemlineata (Say)) is an important pest of the cultivated potato (Solanum tuberosum (L.) [Solanales: Solanaceae]). With its broad resistance toward commonly used insecticides, it is clear that more sophisticated control strategies are needed. Due to their importance in insect development, microRNAs (miRNAs) represent a potential tool to employ in insect control strategies. However, most studies conducted in this area have focused on model species with well-annotated genomes. In this study, next-generation sequencing was used to catalogue the miRNAs produced by L. decemlineata across all eight stages of its development, from eggs to adults. For most stages, the length of miRNAs peaked between 21 and 22 nt, though it was considerably longer for the egg stage (26 nt). Global profiling of miRNAs revealed three distinct developmental clusters: 1) egg stage; 2) early stage (first, second, and third instar); and 3) late stage (fourth instar, prepupae, pupae, and adult). We identified 86 conserved miRNAs and 33 bonafide novel miRNAs, including stage-specific miRNAs and those not previously identified in L. decemlineata. Most of the conserved miRNAs were found in multiple developmental stages, whereas the novel miRNAs were often stage specific with the bulk identified in the egg stage. The identified miRNAs have a myriad of putative functions, including growth, reproduction, and insecticide resistance. We discuss the putative roles of some of the most notable miRNAs in the regulation of L. decemlineata development, as well as the potential applications of this research in Colorado potato beetle management.

Caste-specific microRNA expression in termites: insights into soldier differentiation

Eusocial insects have polyphenic caste systems in which each caste exhibits characteristic morphology and behaviour. In insects, caste systems arose independently in different lineages, such as Isoptera and Hymenoptera. Although partial molecular mechanisms for the development of eusociality in termites have been clarified by the functional analysis of genes and hormones, the contribution of microRNAs (miRNAs) to caste differentiation is unknown. To understand the role of miRNAs in termite caste polyphenism, we performed small RNA sequencing in a subterranean termite (Reticulitermes speratus) and identified the miRNAs that were specifically expressed in the soldier and worker castes. Of the 550 miRNAs annotated in the R. speratus genome, 74 were conserved in insects and 174 were conserved in other termite species. We found that eight miRNAs (mir-1, mir-125, mir-133, mir-2765, mir-87a and three termite-specific miRNAs) are differentially expressed (DE) in soldiers and workers of R. speratus. This differential expression was experimentally verified for five miRNAs by real-time quantitative PCR. Further, four of the eight DE miRNAs in soldier and worker termite castes were also differentially expressed in hymenopteran castes. The finding that Isoptera and Hymenoptera shared several DE miRNAs amongst castes suggests that these miRNAs evolved independently in these phylogenetically distinct lineages.

Method for Detection of miRNAs in Non-Model Organisms with Unreported Database

Non-model organisms are studied very frequently, as a simple accessible and convenient system to investigate the role of miRNAs in particular aspect of biology or disease. However, the unavailability of the annotated genome and hence miRNA database of these non-model organisms pose a major constraint for using them more efficiently. Here, we describe a new method to identify miRNAs in non-model organisms without complex sequencing strategies and using miRNAs from close relative organisms as proxy/reference sequences.

Genome-wide identification, expression profiling, and target gene analysis of microRNAs in the Onion thrips, Thrips tabaci Lindeman (Thysanoptera: Thripidae), vectors of tospoviruses (Bunyaviridae)

Thrips tabaci Lindeman is an important polyphagous insect pest species estimated to cause losses of more than U.S. $1 billion worldwide annually. Chemical insecticides are of limited use in the management of T. tabaci due to the thigmokinetic behavior and development of resistance to insecticides. There is an urgent need to find alternative management strategies. Small noncoding RNAs (sncRNAs) especially microRNAs (miRNAs) hold great promise as key regulators of gene expression in a wide range of organisms. MiRNAs are a group of endogenously originated sncRNA known to regulate gene expression in animals, plants, and protozoans. In this study, we explored these RNAs in T. tabaci using deep sequencing to provide a basis for future studies of their biological and physiological roles in governing gene expression. Apart from snoRNAs and piRNAs, our study identified nine novel and 130 known miRNAs from T. tabaci. Functional classification of the targets for these miRNAs predicted that majority are involved in regulating transcription, translation, signal transduction and genetic information processing. The higher expression of few miRNAs (such as tta-miR-281, tta-miR-184, tta-miR-3533, tta-miR-N1, tta-miR-N7, and tta-miR-N9) in T. tabaci pupal and adult stages reflected their possible role in larval and adult development, metamorphosis, parthenogenesis, and reproduction. This is the first exploration of the miRNAome in T. tabaci, which not only provides insights into their possible role in insect metamorphosis, growth, and development but also offer an important resource for future pest management strategies.

Identification and characterization of microRNAs in the screwworm flies Cochliomyia hominivorax and Cochliomyia macellaria (Diptera: Calliphoridae)

MicroRNAs (miRNAs) are small noncoding RNAs that modulate gene expression through post-transcriptional regulation. Here, we report the identification and characterization of miRNAs in two closely related screwworm flies with different feeding habits: Cochliomyia hominivorax and Cochliomyia macellaria. The New World screwworm, C. hominivorax, is an obligatory parasite of warm-blooded vertebrates, whereas the secondary screwworm, C. macellaria, is a free-living organism that feeds on decaying organic matter. Here, the small RNA transcriptomes of adults and third-instar larvae of both species were sequenced. A total of 110 evolutionarily conserved miRNAs were identified, and 10 putative precursor miRNAs (pre-miRNAs) were predicted. The relative expression of six selected miRNAs was further investigated, including miRNAs that are related to reproduction and neural processes in other insects. Mature miRNAs were also characterized across an evolutionary time scale, suggesting that the majority of them have been conserved since the emergence of the Arthropoda [540 million years ago (Ma)], Hexapoda (488 Ma) and Brachycera (195 Ma) lineages. This study is the first report of miRNAs for screwworm flies. We also performed a comparative analysis with the hereby predicted miRNAs from the sheep blowfly, Lucilia cuprina. The results presented may advance our understanding of parasitic habits within Calliphoridae and assist further functional studies in blowflies.

Identification and characterization of microRNAs expressed in antennae of Holotrichia parallela Motschulsky and their possible roles in olfactory regulation

MicroRNAs (miRNAs) are small noncoding RNAs that play posttranscriptional, regulatory roles in various biological processes. However, there has been limited investigation into the potential function of miRNAs in olfaction. The coleopteran Holotrichia parallela is an economically important pest, and miRNAs have been identified in only one coleopteran (Tribolium castaneum). Therefore, this study was conducted to identify miRNAs expressed in the antennae of H. parallela and obtain insights into their possible roles in olfaction. By combining deep sequencing and miRDeep2 software, a total of 99 miRNAs, including 76 conserved miRNAs and 23 novel miRNAs, were identified from H. parallela antennae. The 76 conserved miRNAs belong to 63 families and the other 23 may be species specific or tissue specific. The identified miRNAs have many conserved features of miRNAs. Evaluation of the conservation of the identified miRNA families across different species revealed that most of the families are insect specific. The prediction and annotation of targets suggested that 13 of the identified miRNAs participate in olfactory regulation. Gender differences in antennal expression of nine of the olfactory-related miRNAs were confirmed by quantitative real-time PCR.

The First Report of miRNAs from a Thysanopteran Insect, Thrips palmi Karny Using High-Throughput Sequencing

Thrips palmi Karny (Thysanoptera: Thripidae) is the sole vector of Watermelon bud necrosis tospovirus, where the crop loss has been estimated to be around USD 50 million annually. Chemical insecticides are of limited use in the management of T. palmi due to the thigmokinetic behaviour and development of high levels of resistance to insecticides. There is an urgent need to find out an effective futuristic management strategy, where the small RNAs especially microRNAs hold great promise as a key player in the growth and development. miRNAs are a class of short non-coding RNAs involved in regulation of gene expression either by mRNA cleavage or by translational repression. We identified and characterized a total of 77 miRNAs from T. palmi using high-throughput deep sequencing. Functional classifications of the targets for these miRNAs revealed that majority of them are involved in the regulation of transcription and translation, nucleotide binding and signal transduction. We have also validated few of these miRNAs employing stem-loop RT-PCR, qRT-PCR and Northern blot. The present study not only provides an in-depth understanding of the biological and physiological roles of miRNAs in governing gene expression but may also lead as an invaluable tool for the management of thysanopteran insects in the future.

Expression profile of androgen-modulated microRNAs in the fetal murine lung

Background

Androgens are known to delay lung development. As a consequence, the incidence and morbidity of respiratory distress syndrome of the neonate are higher for male than for female premature infants. We previously reported that many genes were expressed with a sex difference in the mouse developing lung and that several genes were under the control of androgens in the male fetal lung. microRNAs are small non-coding RNAs known to negatively regulate the expression of specific genes. In this study, we examined whether murine miRNAs are under the control of androgens in the male developing lung.

Methods

Expression profiling of microRNAs was performed by microarrays using RNA extracted from male fetal lungs isolated on gestational day (GD) 17.0 and GD 18.0 after daily injection of pregnant mice from GD 10.0 with the antiandrogen flutamide or vehicle only. To identify putative miRNA target genes, the data obtained here were combined with gene profiling data reported previously using the same RNA preparations. qPCR was used to confirm microarray data with fetal lungs from other litters than those used in microarrays.

Results

Flutamide induced downregulation and upregulation of several miRNAs on GD 17.0 and GD 18.0. Of the 43 mature miRNAs modulated by flutamide on GD 17.0, 60 % were downregulated, whereas this proportion was only of 34 % for the 35 mature miRNAs modulated on GD 18.0. For 29 and 26 flutamide-responsive miRNAs, we found a corresponding target inversely regulated by androgens on GD 17.0 and 18.0, respectively. The androgen-regulated target genes were involved in several biological processes (lipid metabolism, cell proliferation, and lung development) and molecular functions, mainly transcription factor binding.

Conclusions

Regulation of male lung development involves several miRNAs that are under androgen modulation in vivo.

Electronic supplementary material

The online version of this article (doi:10.1186/s13293-016-0072-z) contains supplementary material, which is available to authorized users.

Identification of differentially expressed microRNAs between Bacillus thuringiensis Cry1Ab-resistant and -susceptible strains of Ostrinia furnacalis

The Asian corn borer (ACB), Ostrinia furnacalis (Guenée), can develop strong resistance to Cry1Ab, the most widely commercialized Cry toxin for Bt maize worldwide. It is essential to understand the mechanism of resistance for management of this species, but information on the post-transcriptional regulation of Bt resistance in this target insect is limited. In the present study, RNA was extracted from the ACB in various larval stages (1–5 instar) from Cry1Ab-sensitive (ACB-BtS) and -resistant (ACB-AbR) strains, each of which included two biological replicates. Using Illumina sequencing, a total of 23,809,890 high-quality reads were collected from the four ACB libraries. The numbers of known microRNAs (miRNAs) were 302 and 395 for ACB-BtS and 268 and 287 for ACB-AbR. Using Mireap software, we identified 32 and 16 potential novel miRNAs for ACB-BtS and 18 and 22 for ACB-AbR. Among them, 21 known and 1 novel miRNAs had significantly different expression between ACB-BtS and ACB-AbR. Several miRNAs were observed to target potential Bt receptor genes, such as aminopeptidase N and cadherin-like protein. The glycosylphosphatidylinositol-anchor biosynthetic process and ABC transporters pathway were identified through Gene Ontology and KEGG pathway analysis of target genes of the differentially expressed miRNAs.

Identification of Novel and Conserved microRNAs in Homalodisca vitripennis, the Glassy-Winged Sharpshooter by Expression Profiling

The glassy-winged sharpshooter (GWSS) Homalodisca vitripennis (Hemiptera: Cicadellidae), is a xylem-feeding leafhopper and an important vector of the bacterium Xylella fastidiosa; the causal agent of Pierce’s disease of grapevines. MicroRNAs are a class of small RNAs that play an important role in the functional development of various organisms including insects. In H. vitripennis, we identified microRNAs using high-throughput deep sequencing of adults followed by computational and manual annotation. A total of 14 novel microRNAs that are not found in the miRBase were identified from adult H. vitripennis. Conserved microRNAs were also found in our datasets. By comparison to our previously determined transcriptome sequence of H. vitripennis, we identified the potential targets of the microRNAs in the transcriptome. This microRNA profile information not only provides a more nuanced understanding of the biological and physiological mechanisms that govern gene expression in H. vitripennis, but may also lead to the identification of novel mechanisms for biorationally designed management strategies through the use of microRNAs.

Eupolyphaga sinensis Walker Ethanol Extract Suppresses Cell Growth and Invasion in Human Breast Cancer Cells

AIM OF THE STUDY

To examine the antiproliferation and anti-invasion of Eupolyphaga sinensis Walker 70% ethanol extract (ESWE) on breast cancer and elucidate the underlying signaling mechanisms.

METHODS

MTT and colony formation assays were used to investigate the effect of ESWE on proliferation of breast cancer cells in vitro. The xenograft mouse tumor model was used to determine the effect of ESWE on breast cancer in vivo. To investigate the underlying molecular mechanisms, we used western blotting to analyze the expression of ERK1/2, CXCR4, matrix metalloproteinase 2 (MMP2), and MMP9 pretreated with ESWE. The stromal cell-derived factor (SDF)-1α-induced migration and invasion potential of breast cancer cells were examined by wound-healing assays and Matrigel invasion chamber assays.

RESULTS

ESWE effectively inhibited the proliferation of MDA-MB-435s and MDA-MB-231 cells and exhibited antitumor effects in an MDA-MB-231 xenograft mice model. Furthermore, ESWE suppressed the activity of ERK1/2, a key molecule of MAPK signaling. We also observed that ESWE treatment led to downregulation of CXCR4 expression as well as greatly reduced MMP2 and MMP9. ESWE affected CXCR4 expression partially through the modulation of autocrine vascular endothelial growth factor. However, suppression of CXCR4 expression was the result of downregulation of mRNA expression. Inhibition of CXCR4 expression by ESWE further correlated with the suppression of SDF-1α-induced migration and invasion in breast cancer cells.

CONCLUSION

ESWE exerted its antiproliferation and antiinvasion by regulating MAPK signaling and related metastasis factorsand thus could be a useful therapeutic candidate for breast cancer intervention.

MicroRNAs of two medically important mosquito species: Aedes aegypti and Anopheles stephensi

MicroRNAs (miRNAs) are endogenous, single-stranded small RNAs that have important regulatory functions at the post-transcriptional level. In the present study, we characterize miRNAs in two divergent mosquito species, Aedes aegypti and Anopheles stephensi, through deep sequencing of small RNAs spanning all developmental stages. We discovered eight novel miRNAs in Ae. aegypti and 20 novel miRNAs in An. stephensi, which enabled the first systematic analysis of miRNA evolution in mosquitos. We traced the phylogenetic history of all miRNAs in both species and report a rate of 0.055-0.13 miRNA net gain per million years. Most novel miRNAs originate de novo. Duplications that produced miRNA clusters and families are more common in Ae. aegypti than in An. stephensi. We also identified arm-switch as a source of new miRNAs. Expression profile analysis identified mosquito-specific miRNAs that showed strong stage-specific expression in one or both lineages. For example, the aae-miR-2941/2946 family represents the most abundant maternally deposited and zygotically transcribed miRNAs in Ae. aegypti. miR-2943 is a highly expressed zygotic miRNA in both Ae. aegypti and An. stephensi. Such information provides the basis from which to study the function of these miRNAs in biology common to all mosquitos or unique to one particular lineage.

Influence of sex differences on microRNA gene regulation in disease

Sexual dimorphism is observed in most human diseases. The difference in the physiology and genetics between sexes can contribute tremendously to the disease prevalence, severity, and outcome. Both hormonal and genetic differences between males and females can lead to differences in gene expression patterns that can influence disease risk and course. MicroRNAs have emerged as potential regulatory molecules in all organisms. They can have a broad effect on every aspect of physiology, including embryogenesis, metabolism, and growth and development. Numerous microRNAs have been identified and elucidated to play a key role in cardiovascular diseases, as well as in neurological and autoimmune disorders. This is especially important as microRNA-based tools can be exploited as beneficial therapies for disease treatment and prevention. Sex steroid hormones as well as X-linked genes can have a considerable influence on the regulation of microRNAs. However, there are very few studies highlighting the role of microRNAs in sex biased diseases. This review attempts to summarize differentially regulated microRNAs in males versus females in different diseases and calls for more attention in this underexplored area that should set the basis for more effective therapeutic strategies for sexually dimorphic diseases.

Accuracy of microRNA discovery pipelines in non-model organisms using closely related species genomes

Mapping small reads to genome reference is an essential and more common approach to identify microRNAs (miRNAs) in an organism. Using closely related species genomes as proxy references can facilitate miRNA expression studies in non-model species that their genomes are not available. However, the level of error this introduces is mostly unknown, as this is the result of evolutionary distance between the proxy reference and the species of interest. To evaluate the accuracy of miRNA discovery pipelines in non-model organisms, small RNA library data from a mosquito, Aedes aegypti, were mapped to three well annotated insect genomes as proxy references using miRanalyzer with two strict and loose mapping criteria. In addition, another web-based miRNA discovery pipeline (DSAP) was used as a control for program performance. Using miRanalyzer, more than 80% reduction was observed in the number of mapped reads using strict criterion when proxy genome references were used; however, only 20% reduction was recorded for mapped reads to other species known mature miRNA datasets. Except a few changes in ranking, mapping criteria did not make any significant differences in the profile of the most abundant miRNAs in A. aegypti when its original or a proxy genome was used as reference. However, more variation was observed in miRNA ranking profile when DSAP was used as analysing tool. Overall, the results also suggested that using a proxy reference did not change the most abundant miRNAs' differential expression profiles when infected or non-infected libraries were compared. However, usage of a proxy reference could provide about 67% of the original outcome from more extremely up- or down-regulated miRNA profiles. Although using closely related species genome incurred some losses in the number of miRNAs, the most abundant miRNAs along with their differential expression profile would be acceptable based on the sensitivity level of each project.