Role of microRNAs in insect-baculovirus interactions

Functional regulation of microRNA-184 in the replication and infection of Autographa californica multiple nucleopolyhedrovirus

MicroRNAs (miRNAs) represent a class of short, non-coding RNAs that are widely acknowledged as crucial participants in virus-host interactions. MiR-184, a highly conserved and abundant miRNA in insects, has yet to be extensively studied for its involvement in baculovirus infection. In this study, we investigated how miR-184 affects the infection and replication of Autographa californica multiple nucleopolyhedrovirus (AcMNPV). The results indicated that after AcMNPV infection, there was an initial increase in the expression of miR-184 within 24 h, followed by a subsequent decrease. MiR-184 can inhibit AcMNPV's DNA replication and budded virus production by directly targeting four viral genes, namely ie1, ac66, p49, and lef9. Moreover, suppressing miR-184 expression enhanced the insecticidal efficacy of AcMNPV against Spodoptera exigua larvae and markedly elevated the host ATPase gene expressions. These findings showed that miR-184 had a substantial impact on the interactions between baculoviruses and insects, presenting a prospective candidate for developing highly effective miRNA-based biopesticides.

Unlocking novel therapeutic avenues in glioblastoma: Harnessing 4-amino cyanine and miRNA synergy for next-gen treatment convergence

Glioblastoma (GBM) poses a formidable challenge in oncology due to its aggressive nature and dismal prognosis, with average survival rates around 15 months despite conventional treatments. This review proposes a novel therapeutic strategy for GBM by integrating microRNA (miRNA) therapy with 4-amino cyanine molecules possessing near-infrared (NIR) properties. miRNA holds promise in regulating gene expression, particularly in GBM, making it an attractive therapeutic target. 4-amino cyanine molecules, especially those with NIR properties, have shown efficacy in targeted tumor cell degradation. The combined approach addresses gene expression regulation and precise tumor cell degradation, offering a breakthrough in GBM treatment. Additionally, the review explores noncoding RNAs classification and characteristics, highlighting their role in GBM pathogenesis. Advanced technologies such as antisense oligonucleotides (ASOs), locked nucleic acids (LNAs), and peptide nucleic acids (PNAs) show potential in targeting noncoding RNAs therapeutically, paving the way for precision medicine in GBM. This synergistic combination presents an innovative approach with the potential to advance cancer therapy in the challenging landscape of GBM.

Unraveling the noncoding RNA landscape in glioblastoma: from pathogenesis to precision therapeutics

Glioblastoma (GBM) is an aggressive type IV brain tumor that originates from astrocytes and has a poor prognosis. Despite intensive research, survival rates have not significantly improved. Noncoding RNAs (ncRNAs) are emerging as critical regulators of carcinogenesis, progression, and increased treatment resistance in GBM cells. They influence angiogenesis, migration, epithelial-to-mesenchymal transition, and invasion in GBM cells. ncRNAs, such as long ncRNAs (lncRNAs), microRNAs (miRNAs), and circular RNAs (circRNAs), are commonly dysregulated in GBM. miRNAs, such as miR-21, miR-133a, and miR-27a-3p, are oncogenes that increase cell proliferation, metastasis, and migration by targeting TGFBR1 and BTG2. In contrast, lncRNAs, such as HOXD-AS2 and LINC00511, are oncogenes that increase the migration, invasion, and proliferation of cells. CircRNAs, such as circ0001730, circENTPD7, and circFOXO3, are oncogenes responsible for cell growth, angiogenesis, and viability. Developing novel therapeutic strategies targeting ncRNAs, cell migration, and angiogenesis is a promising approach for GBM. By targeting these dysregulated ncRNAs, we can potentially restore a healthy balance in gene expression and influence disease progression. ncRNAs abound within GBM, demonstrating significant roles in governing the growth and behavior of these tumors. They may also be useful as biomarkers or targets for therapy. The use of morpholino oligonucleotides (MOs) suppressing the oncogene expression of HOTAIR, BCYRN1, and cyrano, antisense oligonucleotides (ASOs) suppressing the expression of ncRNAs such as MALAT1 and miR-10b, locked nucleic acids (LNAs) suppressing miR-21, and peptide nucleic acids (PNAs) suppressing the expression of miR-155 inhibited the PI3K pathway, tumor growth, angiogenesis, proliferation, migration, and invasion. Targeting oncogenic ncRNAs with RNA-interfering strategies such as MOs, ASOs, LNAs, CRISPR-Cas9 gene editing, and PNA approaches may represent a promising therapeutic strategy for GBM. This review emphasizes the critical role of ncRNAs in GBM pathogenesis, as well as the potential for new therapeutic strategies targeting these pathways to improve the prognosis and quality of life for GBM patients.

Comprehensive analysis of changes in expression of lncRNA, microRNA and mRNA in liver tissues of chickens with high or low abdominal fat deposition

1. The liver of chickens is a dominant lipid biosynthetic tissue and plays a vital role in fat deposition, particularly in the abdomen. To determine the molecular mechanisms involved in its lipid metabolism, the livers of chickens with high (H) or low (L) abdominal fat content were sampled and sequencing on long non-coding RNA (lncRNA), messenger RNA (mRNA) and small RNA (microRNA) was performed.2. In total, 351 expressed protein-coding genes for long non-coding RNA (DEL; 201 upregulated and 150 downregulated), 400 differentially expressed genes (DEG; 223 upregulated and 177 downregulated) and 10 differentially expressed miRNA (DEM; four upregulated and six downregulated) were identified between the two groups. Multiple potential signalling pathways related to lipogenesis and lipid metabolism were identified via pathway enrichment analysis. In addition, 173 lncRNA - miRNA - mRNA interaction regulatory networks were identified, including 30 lncRNA, 27 mRNA and seven miRNA.3. These networks may help regulate lipid metabolism and fat deposition. Five promising candidate genes and two lncRNA may play important roles in the regulation of adipogenesis and lipid metabolism in chickens.

A Comprehensive Study of MicroRNA in Baculoviruses

Baculoviruses are viral pathogens that infect different species of Lepidoptera, Diptera, and Hymenoptera, with a global distribution. Due to their biological characteristics and the biotechnological applications derived from these entities, the Baculoviridae family is an important subject of study and manipulation in the natural sciences. With the advent of RNA interference mechanisms, the presence of baculoviral genes that do not code for proteins but instead generate transcripts similar to microRNAs (miRNAs) has been described. These miRNAs are functionally associated with the regulation of gene expression, both in viral and host sequences. This article provides a comprehensive review of miRNA biogenesis, function, and characterization in general, with a specific focus on those identified in baculoviruses. Furthermore, it delves into the specific roles of baculoviral miRNAs in regulating viral and host genes and presents structural and thermodynamic stability studies that are useful for detecting shared characteristics with predictive utility. This review aims to expand our understanding of the baculoviral miRNAome, contributing to improvements in the production of baculovirus-based biopesticides, management of resistance phenomena in pests, enhancement of recombinant protein production systems, and development of diverse and improved BacMam vectors to meet biomedical demands.

Integrated Analysis of MicroRNA and mRNA Expression Profiles in the Fat Bodies of MbMNPV-Infected Helicoverpa armigera

MicroRNAs (miRNAs), are a novel class of gene expression regulators, that have been found to participate in regulating host-virus interactions. However, the function of insect-derived miRNAs in response to virus infection is poorly understood. We analyzed miRNA expression profiles in the fat bodies of Helicoverpa armigera (H. armigera) infected with Mamestra brassicae multiple nucleopolyhedroviruses (MbMNPV). A total of 52 differentially expressed miRNAs (DEmiRNAs) were filtered out through RNA-seq analysis. The targets of 52 DEmiRNAs were predicted and 100 miRNA-mRNA interaction pairs were obtained. The predicted targets of DEmiRNAs were mainly enriched in the Wnt signaling pathway, phagosome, and mTOR signaling pathway, which are related to the virus infection. Real-time PCR was used to verify the RNA sequencing results. ame-miR-317-3p, mse-miR-34, novel1-star, and sfr-miR-6094-5p were shown to be involved in the host response to MbMNPV infection. Results suggest that sfr-miR-6094-5p can negatively regulate the expression of four host genes eIF3-S7, CG7583, CG16901, and btf314, and inhibited MbMNPV infection significantly. Further studies showed that RNAi-mediated knockdown of eIF3-S7 inhibited the MbMNPV infection. These findings suggest that sfr-miR-6094-5p inhibits MbMNPV infection by negatively regulating the expression of eIF3-S7. This study provides new insights into MbMNPV and H. armigera interaction mechanisms.

microRNA-34-5p encoded by Spodoptera frugiperda regulates the replication and infection of Autographa californica multiple nucleopolyhedrovirus by targeting odv-e66, ac78 and ie2

BACKGROUND

Spodoptera frugiperda is one of the significant migratory pests in the Global Alert issued by the Food and Agriculture Organization of the United Nations. As an insect-specific microbial insecticide, baculovirus has been used to control various pests. MicroRNA-34-5p (miR-34-5p) is involved in regulating growth, reproduction and innate immunity to pathogens in insects, playing an essential role in host-virus interactions. In this study, we explored the critical function of miR-34-5p encoded by S. frugiperda in the anti-Autographa californica multiple nucleopolyhedrovirus (AcMNPV), providing a reference for the design of a miR-34-5p target biopesticide against S. frugiperda and a theoretical basis for the wide application of microRNAs (miRNAs) in green pest control technology.

RESULTS

We focused on miR-34-5p identified as downregulated in Sf9 cells and S. frugiperda larvae infected by AcMNPV. The regulatory function of miR-34-5p in AcMNPV-S. frugiperda interactions was studied by transfecting synthetic mimics and inhibitors, and constructing recombinant bacmids with miR-34-5p overexpression. miR-34-5p inhibited the production of infectious budded virions at the cellular and insect levels, inhibited the replication of the viral DNA and glucose metabolism, and increased the transcription of the antimicrobial peptide gloverin. Furthermore, the virus genes odv-e66, ac78 and ie2 were shown to be direct targets.

CONCLUSION

We systematically revealed the mechanism by which miR-34-5p is involved in the insect antiviral process. miR-34-5p inhibited the replication and infection of AcMNPV by directly targeting AcMNPV genes, especially ac78 and ie2. Our study provides a new direction and thinking for the prevention and green control of lepidopteran pests. © 2022 Society of Chemical Industry.

Integrated miRNA and transcriptome profiling to explore the molecular mechanism of Spodoptera frugiperda larval midgut in response to azadirachtin exposure

As a destructive agricultural pest, Spodoptera frugiperda has spread worldwide in the past few years. Azadirachtin, an environmentally friendly and most promising compound, showed adverse effects, including mortality and growth inhibition, against S. frugiperda. While the effects of azadirachtin on the midgut of this pest remain to be determined. In this study, structural damage was observed in the larval midguts of S. frugiperda with azadirachtin exposure. RNA-seq on the larval midguts with different azadirachtin treatments was performed. Compared to the control group, a total of 3344 and 4759 differentially expressed genes (DEGs) were identified in the midguts with 0.1 and 0.5 μg/g azadirachtin exposure, respectively. Among them, the DEGs encoding detoxification enzymes/proteins, immune-related proteins, digestion and absorption-related proteins, and transcript factors were further analyzed. High-throughput sequencing was also used for the identification of differentially expressed microRNAs in different treatments. A total of 153 conserved miRNAs and 147 novel miRNAs were identified, of which 11 and 29 miRNAs were affected by 0.1 and 0.5 μg/g azadirachtin treatments, respectively. The integrated analysis found that 13 and 178 miRNA versus mRNA pairs were acquired in the samples with 0.1 and 0.5 μg/g azadirachtin treatments, respectively. The results of high-throughput sequencing were confirmed by real-time quantitative polymerase chain reaction (RT-qPCR). These results provide useful information for revealing the molecular mechanism of S. frugiperda larval midgut in response to azadirachtin.

BmNPV p35 Reduces the Accumulation of Virus-Derived siRNAs and Hinders the Function of siRNAs to Facilitate Viral Infection

Antiviral immunity involves various mechanisms and responses, including the RNA interference (RNAi) pathway. During long-term coevolution, viruses have gained the ability to evade this defense by encoding viral suppressors of RNAi (VSRs). It was reported that p35 of baculovirus can inhibit cellular small interference RNA (siRNA) pathway; however, the molecular mechanisms underlying p35 as a VSR remain largely unclear. Here, we showed that p35 of Bombyx mori nucleopolyhedrovirus (BmNPV) reduces the accumulation of virus-derived siRNAs (vsiRNAs) mapped to a particular region in the viral genome, leading to an increased expression of the essential genes in this region, and revealed that p35 disrupts the function of siRNAs by preventing them from loading into Argonaute-2 (Ago2). This repressive effect on the cellular siRNA pathway enhances the replication of BmNPV. Thus, our findings illustrate for the first time the inhibitory mechanism of a baculovirus VSR and how this effect influences viral infection.

Virus and endogenous viral element-derived small non-coding RNAs and their roles in insect-virus interaction

RNA interference pathways mediated by different types of small non-coding RNAs (siRNAs, miRNAs and piRNAs) are conserved biological responses to exotic stresses, including viral infection. Aside from the well-established siRNA pathway, the miRNA pathway and the piRNA pathway process viral sequences, exogenously or endogenously, into miRNAs and piRNAs, respectively. During the host-virus interaction, viral sequences, including both coding and non-coding sequences, can be integrated as endogenous viral elements (EVEs) and thereby become present within the germline of a non-viral organism. In recent years, significant progress has been made in characterizing the biogenesis and function of viruses and EVEs associated with snRNAs. Overall, the siRNA pathway acts as the primarily antiviral defense against a wide range of exogenous viruses; the miRNA pathways associated with viruses or EVEs function in antiviral response and host gene regulation; EVE derived piRNAs with a ping-pong signature have the potential to limit cognate viral infection.

Profiling of MicroRNAs in Midguts of Plutella xylostella Provides Novel Insights Into the Bacillus thuringiensis Resistance

The diamondback moth (DBM), Plutella xylostella, one of the most destructive lepidopteran pests worldwide, has developed field resistance to Bacillus thuringiensis (Bt) Cry toxins. Although miRNAs have been reported to be involved in insect resistance to multiple insecticides, our understanding of their roles in mediating Bt resistance is limited. In this study, we constructed small RNA libraries from midguts of the Cry1Ac-resistant (Cry1S1000) strain and the Cry1Ac-susceptible strain (G88) using a high-throughput sequencing analysis. A total of 437 (76 known and 361 novel miRNAs) were identified, among which 178 miRNAs were classified into 91 miRNA families. Transcripts per million analysis revealed 12 differentially expressed miRNAs between the Cry1S1000 and G88 strains. Specifically, nine miRNAs were down-regulated and three up-regulated in the Cry1S1000 strain compared to the G88 strain. Next, we predicted the potential target genes of these differentially expressed miRNAs and carried out GO and KEGG pathway analyses. We found that the cellular process, metabolism process, membrane and the catalytic activity were the most enriched GO terms and the Hippo, MAPK signaling pathway might be involved in Bt resistance of DBM. In addition, the expression patterns of these miRNAs and their target genes were determined by RT-qPCR, showing that partial miRNAs negatively while others positively correlate with their corresponding target genes. Subsequently, novel-miR-240, one of the differentially expressed miRNAs with inverse correlation with its target genes, was confirmed to interact with Px017590 and Px007885 using dual luciferase reporter assays. Our study highlights the characteristics of differentially expressed miRNAs in midguts of the Cry1S1000 and G88 strains, paving the way for further investigation of miRNA roles in mediating Bt resistance.