miRNA-mediated gene silencing by translational repression followed by mRNA deadenylation and decay

Deciphering the urinary microRNAs landscape in nephrotic syndrome: implications as prognostic marker-a non-invasive study

Nephrotic syndrome is a complex renal condition characterized by abnormal protein permeability into the urine space, leading to edema and renal failure. Recent research suggests that deregulation of microRNAs contributes to the pathogenesis of this disease. MicroRNAs are small, non-coding RNA molecules that regulate gene expression by binding to complementary messenger RNA sequences. In this study, we employed bioinformatics techniques to analyze microRNA expression in urine samples from nephrotic syndrome patients and healthy control participants. Our results revealed a significant disruption of microRNA expression profiles in patients with nephrotic syndrome, indicating that these microRNAs may play a crucial role in the disease. This study highlights the potential of urinary microRNAs as biomarkers for nephrotic syndrome and warrants further investigation into their functional significance in the disease pathogenesis.

Discovery and therapeutic exploitation of Master Regulatory miRNAs in Glioblastoma

Glioblastoma is a fatal primary malignant brain tumor. Despite therapies involving surgical resection, chemotherapy, and radiation therapy, the average survival for glioblastoma patients remains at approximately 15 months. MicroRNAs (miRNAs) are short noncoding RNA molecules that regulate the expression of the majority of human genes. Numerous genes are concurrently deregulated in glioblastoma. Consequently, molecular monotherapies have failed to achieve improvements in clinical outcomes. Several lines of evidence suggest that simultaneous targeting of several deregulated molecules is required to achieve better therapies. However, the simultaneous targeting of several deregulated oncogenic drivers is severely limited by the fact that the drugs needed to target many deregulated molecules do not currently exist, and because combining several drugs in a clinical setting leads to an exponential increase in toxicity. We hypothesized that we can develop and use miRNA to simultaneously inhibit multiple deregulated genes for more efficacious glioblastoma therapies. The goal of this study was therefore to identify master regulatory microRNAs (miRNAs) and use them to simultaneously target multiple deregulated molecules for GBM therapy. We defined master regulatory miRNAs as those that target several deregulated genes in glioblastoma. To find master regulatory miRNAs, we first used PAR-CLIP screenings to identify all targets of all miRNAs in glioblastoma cells. We then analyzed TCGA tumor data to determine which of these targets are deregulated in human tumors. We developed and used an algorithm to rank these targets for significance in glioblastoma malignancy based on their magnitude of deregulation, frequency of deregulation, and correlation with patient survival. We then ranked the miRNAs for their capacity of targeting multiple glioblastoma-deregulated genes and therefore the potential to exhibit strong anti-tumor effects when delivered as therapy. Using this strategy, we selected two tumor suppressor master regulatory miRNAs, miR-340, miR-382 and an oncogenic master regulatory miRNA, miR-17. We validated the target genes of the miRNAs and showed that they form part of important glioblastoma regulatory pathways. We then showed that the miRNAs (miR-340 and miR-582) or the miR-17 inhibitor have strong inhibitory effects on glioblastoma cell growth, survival, invasion, stemness and in vivo tumor growth. Ultimately, we developed and successfully tested a new therapeutic approach to delivery miR-340 using MRI guided focused ultrasound and microbubbles (FUS-MB) and special brain penetrating nanoparticles (BPN). This approach resulted in a substantial reduction in tumor volume and prolongation of the survival of glioblastoma-bearing mice and can be translated into clinical trials. We therefore developed and successfully tested a novel strategy to discover and deliver miRNAs for glioblastoma and cancer therapy.

Curcumin prevents dexamethasone-induced activation of the pseudorabies virus in rat pheochromocytoma cells through the miR-155-5p-Aak1-Numb/Notch2 signalling axis

Pseudorabies virus (PRV) causes neurological disorders and organ damage in diseased animals. After initial infection, PRV activity is gradually inhibited; however, stress stimulation increases the host's glucocorticoid levels, which overcomes the inhibition of PRV activity. Curcumin (Cur) helps maintain the inhibitory state of the Epstein-Barr virus, although further research is needed to establish whether Cur can prevent PRV activation triggered by stress hormones. In this study, we used PC-12 cells to determine the effects of Cur on PRV activation. The cells were successfully infected with PRV at a multiplicity of infection of 1 for 24 h, resulting in the inhibition of PRV activity. Following incubation with 0.5 µM dexamethasone (DEX) for 4 h, the inhibition of PRV activity was blocked. Further mechanistic analyses using a dual-luciferase assay revealed that miR-155-5p directly targets and regulates Aak1 and its downstream signalling molecules, Numb and Notch2, in maintaining and disrupting PRV inhibition. Moreover, in vitro experiments using miR-155-5p mimics and inhibitors, combined with Aak1 overexpression and interference, confirmed that the miR-155-5p-Aak1-Numb/Notch2 axis prevented DEX-induced disruption of PRV inhibition by Cur. These findings provide a novel regulatory target for preventing stress-activated PRV and provide evidence for the potential use of Cur as a stress modulator in practical applications.

Perilla frutescens Leaf-Derived Extracellular Vesicle-Like Particles Carry Pab-miR-396a-5p to Alleviate Psoriasis by Modulating IL-17 Signaling

Psoriasis, a chronic inflammatory skin disorder, remains challenging to treat due to poor skin barrier penetration, limited efficacy, and adverse effects of current therapies. Natural plant-derived extracellular vesicle-like particles (EVPs) have emerged as biocompatible carriers for bioactive molecules. Among various medicinal plants screened, Perilla frutescens leaf-derived EVPs (PLEVPs) exhibited strong anti-inflammatory and antioxidant effects. By incorporating PLEVPs into a hydrogel formulation, we enhanced their stability, retention at psoriatic lesions, and transdermal delivery efficiency. In vivo studies demonstrated that the PLEVPs markedly alleviated psoriasis symptoms in both preventive and therapeutic mouse models, outperforming conventional treatments. This effect was attributed to reduced oxidative stress, modulation of Treg cells, and promotion of keratinocyte apoptosis. Transcriptomic analysis revealed enrichment of the interleukin-17 (IL-17) signaling pathway, a major driver of psoriasis, while small RNA sequencing identified pab-miR396a-5p, an endogenous microRNA (miRNA) within PLEVPs, as a key regulator. Mechanistic studies showed that pab-miR396a-5p targets the 3'-untranslated region of plant heat shock protein 83a, a homolog of mammalian heat shock protein 90, leading to the suppression of nuclear factor-kappa B and Janus kinase/signal transducers and activators of transcription signaling, inhibiting the IL-17 signaling pathway. Validation using lipid nanoparticles encapsulating pab-miR396a-5p mimics confirmed comparable therapeutic effects. This study highlights the potential of plant-derived EVPs as carriers of endogenous miRNAs, enabling interkingdom communication and offering a scalable platform for psoriasis therapy.

Mechanistic insights into RNA cleavage by human Argonaute2-siRNA complex

In animals, AGO-clade Argonaute proteins utilize small interfering RNAs (siRNAs) as guides to recognize target with complete complementarity, resulting in target RNA cleavage that is a critical step for target silencing. These proteins feature a constricted nucleic acid-binding channel that limits base pairing between the guide and target beyond the seed region. How the AGO-siRNA complexes overcome this structural limitation and achieve efficient target cleavage remains unclear. We performed cryo-electron microscopy of human AGO-siRNA complexes bound to target RNAs of increasing lengths to examine the conformational changes associated with target recognition and cleavage. Initially, conformational transition propagates from the opening of the PAZ domain and extends through a repositioning of the PIWI-L1-N domain toward the binding channel, facilitating the capture of siRNA-target duplex. Subsequent extension of base pairing drives the downward movement of the PIWI-L1-N domain to enable catalytic activation. Finally, further base pairing toward the 3' end of siRNA destabilizes the PAZ-N domain, resulting in a "uni-lobed" architecture, which might facilitate the multi-turnover action of the AGO-siRNA enzyme complex. In contrast to PIWI-clade Argonautes, the "uni-lobed" structure of the AGO complex makes multiple contacts with the target in the central region of the siRNA-target duplex, positioning it within the catalytic site. Our findings shed light on the stepwise mechanisms by which the AGO-siRNA complex executes target RNA cleavage and offer insights into the distinct operational modalities of AGO and PIWI proteins in achieving such cleavage.

Circulating MicroRNAs: functional biomarkers for melanoma prognosis and treatment

MicroRNAs (miRNAs) hold significant promise as circulating cancer biomarkers and unlike many other molecular markers, they can provide valuable insights that extend beyond tumour biology. The expression of circulating miRNAs may parallel the cellular composition and dynamic activity within the tumour microenvironment and reveal systemic immune responses. The functional complexity of miRNAs-where a single miRNA can regulate multiple messenger RNAs (mRNAs) to fine tune fundamental processes, and a single mRNA can be targeted by multiple miRNAs-underscores their broad significance and impact. However, this complexity poses significant challenges for translating miRNA research into clinical practice. In melanoma, specific miRNA signatures have shown notable diagnostic, prognostic and predictive value, with lineage-specific and immune-related miRNAs frequently identified as valuable markers. In this review, we explore the role of circulating miRNAs as potential biomarkers in melanoma, and highlight the current status and advances required to translate miRNA research into therapeutic opportunities.

Exploring the CNOT1(800-999) HEAT Domain and Its Interactions with Tristetraprolin (TTP) as Revealed by Hydrogen/Deuterium Exchange Mass Spectrometry

CNOT1, a key scaffold in the CCR4-NOT complex, plays a critical role in mRNA decay, particularly in the regulation of inflammatory responses through its interaction with tristetraprolin. A fragment of the middle part of CNOT1 (residues 800-999) is an example of an α-helical HEAT-like repeat domain. The HEAT motif is an evolutionarily conserved motif present in scaffolding and transport proteins across a wide range of organisms. Using hydrogen/deuterium exchange mass spectrometry (HDX MS), a method that has not been widely explored in the context of HEAT repeats, we analysed the structural dynamics of wild-type CNOT1(800-999) and its two double point mutants (E893A/Y900A, E893Q/Y900H) to find the individual contributions of these CNOT1 residues to the molecular recognition of tristetraprolin (TTP). Our results show that the differences in the interactions of CNOT1(800-999) variants with the TTP peptide fragment are due to the absence of the critical residues resulting from point mutations and not due to the perturbation of the protein structure. Nevertheless, the HDX MS was able to detect slight local changes in structural dynamics induced by protein point mutations, which are usually neglected in studies of intermolecular interactions.

Good things come in small packages: The discovery of small RNAs in the smallest animal model

The 2024 Nobel Prize in Physiology or Medicine has been awarded to two pioneering researchers, Victor Ambros and Gary Ruvkun, marking the fourth time research using Caenorhabditis elegans (C. elegans) has received this prestigious recognition. With a rapid life cycle of just 3.5 days and four distinct larval stages, C. elegans serves as an ideal model for exploring complex genetic mechanisms, particularly heterochronic gene regulation. Ambros and Ruvkun's groundbreaking work on lin-4 and lin-14 genes in C. elegans revealed that lin-4 functions as a 22-nucleotide small RNA-now known as a microRNA (miRNA)-that binds complementarily to the 3' UTR of lin-14 mRNA, effectively inhibiting LIN-14 protein synthesis. This discovery was the first demonstration of miRNA in post-transcriptional gene regulation, a finding that has since reshaped our understanding of genetic regulation across species. Their research on small RNAs in C. elegans not only opened a new paradigm in molecular biology but also highlighted the power of this model organism in uncovering universal biological principles.

MicroRNA-505-5p/-3p Regulates the Proliferation, Invasion, Apoptosis, and Temozolomide Resistance in Mesenchymal Glioma Stem Cells by Targeting AUF1

Mesenchymal glioma stem cells (MES-GSCs) are a major subtype of GSCs that reside within glioma tissues and contribute to metastasis, therapy resistance, and glioma recurrence. However, the precise molecular mechanisms governing MES-GSC functions remain elusive. Our findings revealed that expression levels of miR-505-5p/-3p are elevated in MES-GSCs compared with those in proneural (PN)-GSCs, glioma cell lines, and normal brain tissue and that miR-505-5p/-3p expression levels are decreased in differentiated MES-GSCs. We assumed that miR-505-5p/-3p would play distinctive roles in MES-GSCs and performed loss-of-function experiments targeting miR-505-5p/-3p. Knockdown of miR-505-5p/-3p increased proliferation and promoted differentiation in MES-GSCs while suppressing invasion, temozolomide resistance, and enhancing apoptosis in MES-GSCs. Mechanistically, miR-505-5p/-3p directly targets the 3' UTR of AUF1, leading to its repression in MES-GSCs. Notably, AUF1 expression levels were significantly lower in MES-GSCs compared with those in PN-GSCs, glioma cell lines, and normal brain tissues. Co-inhibition of AUF1 expression with miR-505-5p/-3p knockdown ameliorated the observed cellular phenotypes caused by miR-505-5p/-3p knockdown in MES-GSCs. These results suggest that miR-505-5p/-3p exerts MES-GSC-specific roles in regulating proliferation, differentiation, invasion, apoptosis, and temozolomide resistance by repressing AUF1 expression.

Sperm-borne small non-coding RNAs: potential functions and mechanisms as epigenetic carriers

Over the past two decades, the study of sperm-borne small non-coding RNAs (sncRNAs) has garnered substantial growth. Once considered mere byproducts during germ cell maturation, these sncRNAs have now been recognized as crucial carriers of epigenetic information, playing a significant role in transmitting acquired traits from paternal to offspring, particularly under environmental influences. A growing body of evidence highlights the pivotal role of these sncRNAs in facilitating epigenetic inheritance across generations. However, the exact mechanisms through which these paternally supplied epigenetic carriers operate remain unclear and are under hot debate. This concise review presents the most extensive evidence to date on environmentally-responsive sperm-borne sncRNAs, encompassing brief summary of their origin, dynamics, compartmentalization, characteristics, as well as in-depth elaboration of their functional roles in epigenetic and transgenerational inheritance. Additionally, the review delves into the potential mechanisms by which sperm-delivered sncRNAs may acquire and transmit paternally acquired traits to offspring, modulating zygotic gene expression and influencing early embryonic development.

ncRNA Editing: Functional Characterization and Computational Resources

Non-coding RNAs (ncRNAs) play crucial roles in gene expression regulation, translation, and disease development, including cancer. They are classified by size in short and long non-coding RNAs. This chapter focuses on the functional implications of adenosine-to-inosine (A-to-I) RNA editing in both short (e.g., miRNAs) and long ncRNAs. RNA editing dynamically alters the sequence and structure of primary transcripts, impacting ncRNA biogenesis and function. Notable findings include the role of miRNA editing in promoting glioblastoma invasiveness, characterizing RNA editing hotspots across cancers, and its implications in thyroid cancer and ischemia. This chapter also highlights bioinformatics resources and next-generation sequencing (NGS) technologies that enable comprehensive ncRNAome studies and genome-wide RNA editing detection. Dysregulation of RNA editing machinery has been linked to various human diseases, emphasizing the potential of RNA editing as a biomarker and therapeutic target. This overview integrates current knowledge and computational tools for studying ncRNA editing, providing insights into its biological significance and clinical applications.

Out-of-Equilibrium ceRNA Crosstalk

Among non-coding RNAs, microRNAs are pivotal post-transcriptional regulators of gene expression in higher eukaryotes. Through a titration-based mechanism of interaction with their target RNAs, microRNAs can mediate a weak but pervasive form of RNA cross-regulation, as different endogenous RNAs can be effectively coupled by competing for microRNA binding (a phenomenon now known as "crosstalk"). Mathematical modeling has been proven of great help in unraveling many features of these competing endogenous RNA (ceRNA) interactions. However, although many studies have been devoted to the steady-state properties of this indirect regulatory layer, little is known about how the information encoded in frequency, amplitude, duration, and other features of regulatory signals can affect the resulting ceRNA crosstalk picture and hence the overall patterns of gene expression. Here, we focus on such dynamical aspects, with a special emphasis on the encoding and decoding of time-dependent signals.

Gra-CRC-miRTar: The pre-trained nucleotide-to-graph neural networks to identify potential miRNA targets in colorectal cancer

Colorectal cancer (CRC) is the third most diagnosed cancer and the second deadliest cancer worldwide representing a major public health problem. In recent years, increasing evidence has shown that microRNA (miRNA) can control the expression of targeted human messenger RNA (mRNA) by reducing their abundance or translation, acting as oncogenes or tumor suppressors in various cancers, including CRC. Due to the significant up-regulation of oncogenic miRNAs in CRC, elucidating the underlying mechanism and identifying dysregulated miRNA targets may provide a basis for improving current therapeutic interventions. In this paper, we proposed Gra-CRC-miRTar, a pre-trained nucleotide-to-graph neural network framework, for identifying potential miRNA targets in CRC. Different from previous studies, we constructed two pre-trained models to encode RNA sequences and transformed them into de Bruijn graphs. We employed different graph neural networks to learn the latent representations. The embeddings generated from de Bruijn graphs were then fed into a Multilayer Perceptron (MLP) to perform the prediction tasks. Our extensive experiments show that Gra-CRC-miRTar achieves better performance than other deep learning algorithms and existing predictors. In addition, our analyses also successfully revealed 172 out of 201 functional interactions through experimentally validated miRNA-mRNA pairs in CRC. Collectively, our effort provides an accurate and efficient framework to identify potential miRNA targets in CRC, which can also be used to reveal miRNA target interactions in other malignancies, facilitating the development of novel therapeutics. The Gra-CRC-miRTar web server can be found at: http://gra-crc-mirtar.com/.

Evolving landscape of detection and targeting miRNA/epigenetics for therapeutic strategies in ovarian cancer

Ovarian cancer (OC) accounts for the highest mortality rates among all gynecologic malignancies. The high mortality of OC is often associated with delayed detection, prolonged latency, enhanced metastatic potential, acquired drug resistance, and frequent recurrence. This review comprehensively explores key aspects of OC, including cancer diagnosis, mechanisms of disease resistance, and the pivotal role of epigenetic regulation, particularly by microRNAs (miRs) in cancer progression. We highlight the intricate regulatory mechanisms governing miR expression within the context of OC and the current status of epigenetic advancement in the therapeutic development and clinical trial progression. Through network analysis we elucidate the regulatory interactions between dysregulated miRs in OC and their targets which are involved in different signaling pathways. By exploring these interconnected facets and critical analysis, we endeavor to provide a nuanced understanding of the molecular dynamics underlying OC, its detection and shedding light on potential avenues for miRs and epigenetics-based therapeutic intervention and management strategies.

Small and long non-coding RNAs: Past, present, and future

Since the introduction of the central dogma of molecular biology in 1958, various RNA species have been discovered. Messenger RNAs transmit genetic instructions from DNA to make proteins, a process facilitated by housekeeping non-coding RNAs (ncRNAs) such as small nuclear RNAs (snRNAs), ribosomal RNAs (rRNAs), and transfer RNAs (tRNAs). Over the past four decades, a wide array of regulatory ncRNAs have emerged as crucial players in gene regulation. In celebration of Cell's 50th anniversary, this Review explores our current understanding of the most extensively studied regulatory ncRNAs-small RNAs and long non-coding RNAs (lncRNAs)-which have profoundly shaped the field of RNA biology and beyond. While small RNA pathways have been well documented with clearly defined mechanisms, lncRNAs exhibit a greater diversity of mechanisms, many of which remain unknown. This Review covers pivotal events in their discovery, biogenesis pathways, evolutionary traits, action mechanisms, functions, and crosstalks among ncRNAs. We also highlight their roles in pathophysiological contexts and propose future research directions to decipher the unknowns of lncRNAs by leveraging lessons from small RNAs.

Intervention strategies targeting virus and host factors against porcine reproductive and respiratory syndrome virus: A systematic review

Porcine reproductive and respiratory syndrome (PRRS) caused by porcine reproductive and respiratory syndrome virus (PRRSV) causes considerable economic losses to the global swine industry every year and seriously hinders the healthy development of this industry. Although tremendous efforts have been made over the past 30 years toward the development of prevention and control strategies against PRRSV infection, to date, treatments with proven efficacy have yet to be available due to our incomplete understanding of the molecular basis and complexity of the infection machinery. This review systematically discusses recent advances in the research and development of anti-PRRSV therapies targeting different stages of the viral life cycle. Furthermore, this review puts forward novel intervention targets and research approaches based on our in-depth exploration of virus-host interactions and the latest biological technologies, which have the potential to complement or transform current anti-PRRSV strategies and become breakthrough points for the control of PRRS in the future.

Non-Coding RNAs and Innate Immune Responses in Cancer

Non-coding RNAs (ncRNAs) and the innate immune system are closely related, acting as defense mechanisms and regulating gene expression and innate immunity. Both are modulators in the initiation, development and progression of cancer. We aimed to review the major types of ncRNAs, including small interfering RNAs (siRNAs), microRNAs (miRNAs), piwi-interacting RNAs (piRNAs), and long non-coding RNAs (lncRNAs), with a focus on cancer, innate immunity, and inflammation. We found that ncRNAs are closely related to innate immunity, epigenetics, chronic inflammation, and cancer and share properties such as inducibility, specificity, memory, and transfer. These similarities and interrelationships suggest that ncRNAs and modulators of trained immunity, together with the control of chronic inflammation, can be combined to develop novel therapeutic approaches for personalized cancer treatment. In conclusion, the close relationship between ncRNAs, the innate immune system, and inflammation highlights their importance in cancer pathways and their potential as targets for novel therapeutic strategies.

The identification of key molecules and pathways in the crosstalk of calcium oxalate-treated TCMK-1 cells and macrophage via exosomes

The interplay between crystals and epithelial cells forms the cornerstone of kidney stone development, communication between epithelial cells and macrophages emerging as a pivotal role in this process. We conducted next-generation sequencing on the secreted exosomes of TCMK-1 cells treated with calcium oxalate monohydrate (OX_EXO) or controls (NC_EXO), and on the macrophage cell line RAW264.7 stimulated with OX_EXO or NC_EXO, followed by validation of differentially expressed target proteins and miRNAs through Western blot and PCR. UPSET plots were employed to identify genes co-targeted by exosomal miRNAs. Various bioinformatic analyses were employed to predict potential mechanisms of the dysregulated genes. We integrated sequencing data from the GEO database, and validated findings using clinical patient urine and kidney tissues. We identified 665 differentially expressed exosomal miRNAs between OX_EXO and NC_EXO. Among the top 10 down-regulated miRNAs, the most targeted genes were AAK1 and NUFIP2, whereas PLCB1 was significantly targeted among the top 10 up-regulated miRNAs. In clinical specimens, we confirmed the differential expressions of five homologous miRNAs, as well as CNOT3, CNCNA1C, APEX1, and TMEM199. In conclusion, treatment of TCMK-1 cells with calcium oxalate significantly alerted the expression profile of exosomal miRNAs, subsequently influencing gene expression in macrophages, thereby modulating the processes of kidney stone formation.

The Growing Class of Novel RNAi Therapeutics

The clinical use of RNA interference (RNAi) molecular mechanisms has introduced a novel, growing class of RNA therapeutics capable of treating diseases by controlling target gene expression at the posttranscriptional level. With the newly approved nedosiran (Rivfloza), there are now six RNAi-based therapeutics approved by the United States Food and Drug Administration (FDA). Interestingly, five of the six FDA-approved small interfering RNA (siRNA) therapeutics [patisiran (Onpattro), lumasiran (Oxlumo), inclisiran (Leqvio), vutrisiran (Amvuttra), and nedosiran] were revealed to act on the 3'-untranslated regions of target mRNAs, instead of coding sequences, thereby following the common mechanistic action of genome-derived microRNAs (miRNA). Furthermore, three of the FDA-approved siRNA therapeutics [patisiran, givosiran (Givlaari), and nedosiran] induce target mRNA degradation or cleavage via near-complete rather than complete base-pair complementarity. These features along with previous findings confound the currently held characteristics to distinguish siRNAs and miRNAs or biosimilars, of which all converge in the RNAi regulatory pathway action. Herein, we discuss the RNAi mechanism of action and current criteria for distinguishing between miRNAs and siRNAs while summarizing the common and unique chemistry and molecular pharmacology of the six FDA-approved siRNA therapeutics. The term "RNAi" therapeutics, as used previously, provides a coherently unified nomenclature for broader RNAi forms as well as the growing number of therapeutic siRNAs and miRNAs or biosimilars that best aligns with current pharmacological nomenclature by mechanism of action. SIGNIFICANCE STATEMENT: The common and unique chemistry and molecular pharmacology of six FDA-approved siRNA therapeutics are summarized, in which nedosiran is newly approved. We point out rather a surprisingly mechanistic action as miRNAs for five siRNA therapeutics and discuss the differences and similarities between siRNAs and miRNAs that supports using a general and unified term "RNAi" therapeutics to align with current drug nomenclature criteria in pharmacology based on mechanism of action and embraces broader forms and growing number of novel RNAi therapeutics.

Integrin restriction by miR-34 protects germline progenitors from cell death during aging

During aging, regenerative tissues must dynamically balance the two opposing processes of proliferation and cell death. While many microRNAs are differentially expressed during aging, their roles as dynamic regulators of tissue regeneration have yet to be described. We show that in the highly regenerative Drosophila testis, miR-34 levels are significantly elevated during aging. miR-34 modulates germ cell death and protects the progenitor germ cells from accelerated aging. However, miR-34 is not expressed in the progenitors themselves but rather in neighboring cyst cells that kill the progenitors. Transcriptomics followed by functional analysis revealed that during aging, miR-34 modifies integrin signaling by limiting the levels of the heterodimeric integrin receptor αPS2 and βPS subunits. In addition, we found that in cyst cells, this heterodimer is essential for inducing phagoptosis and degradation of the progenitor germ cells. Together, these data suggest that the miR-34-integrin signaling axis acts as a sensor of progenitor germ cell death to extend progenitor functionality during aging.

Predicting functional UTR variants by integrating region-specific features

The untranslated region (UTR) of messenger ribonucleic acid (mRNA), including the 5'UTR and 3'UTR, plays a critical role in regulating gene expression and translation. Variants within the UTR can lead to changes associated with human traits and diseases; however, computational prediction of UTR variant effect is challenging. Current noncoding variant prediction mainly focuses on the promoters and enhancers, neglecting the unique sequence of the UTR and thereby limiting their predictive accuracy. In this study, using consolidated datasets of UTR variants from disease databases and large-scale experimental data, we systematically analyzed more than 50 region-specific features of UTR, including functional elements, secondary structure, sequence composition and site conservation. Our analysis reveals that certain features, such as C/G-related sequence composition in 5'UTR and A/T-related sequence composition in 3'UTR, effectively differentiate between nonfunctional and functional variant sets, unveiling potential sequence determinants of functional UTR variants. Leveraging these insights, we developed two classification models to predict functional UTR variants using machine learning, achieving an area under the curve (AUC) value of 0.94 for 5'UTR and 0.85 for 3'UTR, outperforming all existing methods. Our models will be valuable for enhancing clinical interpretation of genetic variants, facilitating the prediction and management of disease risk.

Gra-CRC-miRTar: The pre-trained nucleotide-to-graph neural networks to identify potential miRNA targets in colorectal cancer

Colorectal cancer (CRC) is the third most diagnosed cancer and the second deadliest cancer worldwide representing a major public health problem. In recent years, increasing evidence has shown that microRNA (miRNA) can control the expression of targeted human messenger RNA (mRNA) by reducing their abundance or translation, acting as oncogenes or tumor suppressors in various cancers, including CRC. Due to the significant up-regulation of oncogenic miRNAs in CRC, elucidating the underlying mechanism and identifying dysregulated miRNA targets may provide a basis for improving current therapeutic interventions. In this paper, we proposed Gra-CRC-miRTar, a pre-trained nucleotide-to-graph neural network framework, for identifying potential miRNA targets in CRC. Different from previous studies, we constructed two pre-trained models to encode RNA sequences and transformed them into de Bruijn graphs. We employed different graph neural networks to learn the latent representations. The embeddings generated from de Bruijn graphs were then fed into a Multilayer Perceptron (MLP) to perform the prediction tasks. Our extensive experiments show that Gra-CRC-miRTar achieves better performance than other deep learning algorithms and existing predictors. In addition, our analyses also successfully revealed 172 out of 201 functional interactions through experimentally validated miRNA-mRNA pairs in CRC. Collectively, our effort provides an accurate and efficient framework to identify potential miRNA targets in CRC, which can also be used to reveal miRNA target interactions in other malignancies, facilitating the development of novel therapeutics.

miRNA Dynamics for Pest Management: Implications in Insecticide Resistance

Utilizing chemical agents in pest management in modern agricultural practices has been the predominant approach since the advent of synthetic insecticides. However, insecticide resistance is an emerging issue, as pest populations evolve to survive exposure to chemicals that were once effective in controlling them, underlining the need for advanced and innovative approaches to managing pests. In insects, microRNAs (miRNAs) serve as key regulators of a wide range of biological functions, characterized by their dynamic expression patterns and the ability to target genes. Recent studies are increasingly attributed to the significance of miRNAs in contributing to the evolution of insecticide resistance in numerous insect species. Abundant miRNAs have been discovered in insects using RNA sequencing and transcriptome analysis and are known to play vital roles in regulation at both the transcriptional and post-transcriptional levels. Globally, there is growing research interest in the characterization and application of miRNAs, especially for their potential role in managing insecticide resistance. This review focuses on how miRNAs contribute to regulating insecticide resistance across various insect species. Furthermore, we discuss the gain and loss of functions of miRNAs and the techniques for delivering miRNAs into the insect system. The review emphasizes the application of miRNA-based strategies to studying their role in diminishing insecticide resistance, offering a more efficient and lasting approach to insect management.

Navigating translational control of gene expression in satellite cells

Satellite cells, named for their satellite position around the sarcolemma of the myofibre, are responsible for skeletal muscle regeneration. Satellite cells normally reside in a quiescent state, but rapidly activate the myogenic program and the cell cycle in response to injury. Translational control of gene expression has emerged as an important regulator of satellite cell activity. Quiescent satellite cells maintain low levels of protein synthesis and selectively translate specific mRNAs to conserve limited energy. Activated satellite cells rapidly restore global protein synthesis to meet the demands of proliferating myogenic progenitors that participate in muscle repair. We propose a model by which translational control enables rapid protein level changes in response to injury-induced environmental shifts, serving as both a brake mechanism during quiescence and an accelerator for injury response. In this Chapter, we navigate the processing, translation and metabolism of newly transcribed mRNAs. We review the modifications of mRNA that occur during mRNA processing in the nucleus of satellite cells, and illustrate how these modifications impact the translation and stability of mRNAs. In the cytoplasm, we review how pathways work in concert to regulate protein synthesis globally, while trans acting microRNAs and RNA binding proteins modify specific mRNA translation within a context of tightly regulated protein synthesis. While navigating translational control of gene expression in satellite cells, this chapter reveals that despite significant progress, the field remains nascent in the broader scope of translational control in cell biology. We propose that future investigations will benefit from incorporating emerging global analyses to study translational control of gene expression in rare satellite cells, and we pose unanswered questions that warrant future exploration.

Regulatory role of RNA-binding proteins in microRNA biogenesis

MicroRNAs (miRNAs) are small non-coding RNAs that silence gene expression through their interaction with complementary sequences in the 3' untranslated regions (UTR) of target mRNAs. miRNAs undergo a series of steps during their processing and maturation, which are tightly regulated to fine-tune their abundance and ability to function in post-transcriptional gene silencing. miRNA biogenesis typically involves core catalytic proteins, namely, Drosha and Dicer, and several other RNA-binding proteins (RBPs) that recognize and interact with miRNA precursors and/or their intermediates, and mature miRNAs along with their interacting proteins. The series of RNA-protein and protein-protein interactions are critical to maintaining miRNA expression levels and their function, underlying a variety of cellular processes. Throughout this article, we review RBPs that play a role in miRNA biogenesis and focus on their association with components of the miRNA pathway with functional consequences in the processing and generation of mature miRNAs.

EARLY FLOWERING is a dominant gain-of-function allele of FANTASTIC FOUR 1/2c that promotes early flowering in tomato

Flowering time, an important factor in plant adaptability and genetic improvement, is regulated by various genes in tomato (Solanum lycopersicum). In this study, we characterized a tomato mutant, EARLY FLOWERING (EF), that developed flowers much earlier than its parental control. EF is a dominant gain-of-function allele with a T-DNA inserted 139 bp downstream of the stop codon of FANTASTIC FOUR 1/2c (FAF1/2c). The transcript of SlFAF1/2c was at elevated levels in the EF mutant. Overexpressing SlFAF1/2c in tomato plants phenocopied the early flowering trait of the EF mutant. Knocking out SlFAF1/2c in the EF mutant reverted the early flowering phenotype of the mutant to the normal flowering time of the wild-type tomato plants. SlFAF1/2c promoted the floral transition by shortening the vegetative phase rather than by reducing the number of leaves produced before the emergence of the first inflorescence. The COP9 signalosome subunit 5B (CSN5B) was shown to interact with FAF1/2c, and knocking out CSN5B led to an early flowering phenotype in tomato. Interestingly, FAF1/2c was found to reduce the accumulation of the CSN5B protein by reducing its protein stability. These findings imply that FAF1/2c regulates flowering time in tomato by reducing the accumulation and stability of CSN5B, which influences the expression of SINGLE FLOWER TRUSS (SFT), JOINTLESS (J) and UNIFLORA (UF). Thus, a new allele of SlFAF1/2c was discovered and found to regulate flowering time in tomato.

MicroRNA-194-5p/Heparin-binding EGF-like growth factor signaling mediates dexamethasone-induced activation of pseudorabies virus in rat pheochromocytoma cells

Pseudorabies virus (PRV) is a neurotropic virus, which infects a wide range of mammals. The activity of PRV is gradually suppressed in hosts that have tolerated the primary infection. Increased glucocorticoid levels resulting from stressful stimuli overcome repression of PRV activity. However, the host cell mechanism involved in the activation processes under stressful conditions remains unclear. In this study, infection of rat PC-12 pheochromocytoma cells with neuronal properties using PRV at a multiplicity of infection (MOI) = 1 for 24 h made the activity of PRV be the relatively repressed state, and then incubation with 0.5 μM of the corticosteroid dexamethasone (DEX) for 4 h overcomes the relative repression of PRV activity. RNA-seq deep sequencing and bioinformatics analyses revealed different microRNA and mRNA profiles of PC-12 cells with/without PRV and/or DEX treatment. qRT-PCR and western blot analyses confirmed the negative regulatory relationship of miRNA-194-5p and its target heparin-binding EGF-like growth factor (Hbegf); a dual-luciferase reporter assay revealed that Hbegf is directly targeted by miRNA-194-5p. Further, miRNA-194-5p mock transfection contributed to PRV activation, Hbegf was downregulated in DEX-treated PRV infection cells, and Hbegf overexpression contributed to returning activated PRV to the repression state. Moreover, miRNA-194-5p overexpression resulted in reduced levels of HBEGF, c-JUN, and p-EGFR, whereas Hbegf overexpression suppressed the reduction caused by miRNA-194-5p overexpression. Overall, this study is the first to report that changes in the miR-194-5p-HBEGF/EGFR pathway in neurons are involved in DEX-induced activation of PRV, laying a foundation for the clinical prevention of stress-induced PRV activation.

Time- and sex-dependent delayed effects of acute radiation exposure manifest via miRNA dysregulation

The detrimental effects of high-dose ionizing radiation on human health are well-known, but the influence of sex differences on the delayed effects of acute radiation exposure (DEARE) remains unclear. Here, we conducted six-month animal experiments using escalating radiation doses (7-9 Gy) on male and female C57BL/6 mice. The results show that female mice exhibited greater resistance to radiation, showing increased survival at six months post-total body irradiation. LD50/30 (lethal dose expected to cause 50% lethality in 30 days) for female mice is 8.08 Gy, while for male mice it is 7.76 Gy. DEARE causes time- and sex-dependent dysregulation of microRNA expression, processing enzymes, and the HOTAIR regulatory pathway. Differential regulation of molecular patterns associated with growth, development, apoptosis, and cancer is also observed in male and female mice. These findings shed light on the molecular basis of age and sex differences in DEARE response and emphasize the importance of personalized medicine for mitigating radiation-induced injuries and diseases.

MicroRNAs and Cardiovascular Disease Risk

PURPOSE OF REVIEW

MicroRNAs (miRNAs)-short, non-coding RNAs-play important roles in almost all aspects of cardiovascular biology, and changes in intracellular miRNA expression are indicative of cardiovascular disease development and progression. Extracellular miRNAs, which are easily measured in blood and can be reflective of changes in intracellular miRNA levels, have emerged as potential non-invasive biomarkers for disease. This review summarizes current knowledge regarding miRNAs as biomarkers for assessing cardiovascular disease risk and prognosis.

RECENT FINDINGS

Numerous studies over the last 10-15 years have identified associations between extracellular miRNA profiles and cardiovascular disease, supporting the potential use of extracellular miRNAs as biomarkers for risk stratification. However, clinical application of extracellular miRNA profiles has been hampered by poor reproducibility and inter-study variability that is due largely to methodological differences between studies. While recent studies indicate that circulating extracellular miRNAs are promising biomarkers for cardiovascular disease, evidence for clinical implementation is lacking. This highlights the need for larger, well-designed studies that use standardized methods for sample preparation, miRNA isolation, quantification, and normalization.

Posttranscriptional Events Orchestrate Immune Homeostasis of CD8+ T Cells

Maintaining immune homeostasis is instrumental for host health. Immune cells, such as T cells, are instrumental for the eradication of pathogenic bacteria, fungi and viruses. Furthermore, T cells also play a major role in the fight against cancer. Through the formation of immunological memory, a pool of antigen-experienced T cells remains in the body to rapidly protect the host upon reinfection or retransformation. In order to perform their protective function, T cells produce cytolytic molecules, such as granzymes and perforin, and cytokines such as interferon γ and tumor necrosis factor α. Recently, it has become evident that posttranscriptional regulatory events dictate the kinetics and magnitude of cytokine production by murine and human CD8+ T cells. Here, the recent literature regarding the role posttranscriptional regulation plays in maintaining immune homeostasis of antigen-experienced CD8+ T cells is reviewed.

The lncRNA Malat1 inhibits miR-15/16 to enhance cytotoxic T cell activation and memory cell formation

Proper activation of cytotoxic T cells via the T cell receptor and the costimulatory receptor CD28 is essential for adaptive immunity against viruses, intracellular bacteria, and cancers. Through biochemical analysis of RNA:protein interactions, we uncovered a non-coding RNA circuit regulating activation and differentiation of cytotoxic T cells composed of the long non-coding RNA Malat1 (Metastasis Associated Lung Adenocarcinoma Transcript 1) and the microRNA family miR-15/16. miR-15/16 is a widely and highly expressed tumor suppressor miRNA family important for cell proliferation and survival. miR-15/16 play important roles in T cell responses to viral infection, including the regulation of antigen-specific T cell expansion and memory. Comparative Argonaute-2 high-throughput sequencing of crosslinking immunoprecipitation (AHC) combined with gene expression profiling in normal and miR-15/16-deficient mouse T cells revealed a large network of hundreds of direct miR-15/16 target mRNAs, many with functional relevance for T cell activation, survival and memory formation. Among these targets, Malat1 contained the largest absolute magnitude miR-15/16-dependent AHC peak. This binding site was among the strongest lncRNA:miRNA interactions detected in the T cell transcriptome. We used CRISPR targeting with homology directed repair to generate mice with a 5-nucleotide mutation in the miR-15/16-binding site in Malat1. This mutation interrupted Malat1:miR-15/16 interaction, and enhanced the repression of other miR-15/16 target genes, including CD28. Interrupting Malat1 interaction with miR-15/16 decreased cytotoxic T cell activation, including the expression of interleukin 2 (IL-2) and a broader CD28-responsive gene program. Accordingly, Malat1 mutation diminished memory cell persistence in mice following LCMV Armstrong and Listeria monocytogenes infection. This study marks a significant advance in the study of long non-coding RNAs in the immune system by ascribing cell-intrinsic, sequence-specific in vivo function to Malat1. These findings have implications for T cell-mediated autoimmune diseases, antiviral and anti-tumor immunity, as well as lung adenocarcinoma and other malignancies where Malat1 is overexpressed.

Novel ginsenoside monomer RT4 promotes colitis repair in mice by regulating miR-144-3p/SLC7A11 signaling pathway

BACKGROUND

Ginsenoside RT4 (RT4) is a new biologically active compound extracted from ginseng that possesses numerous medicinal and pharmacological properties. However, its potential therapeutic effect of ginsenoside RT4 on ulcerative colitis remains unknown.

METHODS AND RESULTS

In this study, we investigated the anti-inflammatory effects of ginsenoside RT4 and its underlying molecular mechanism in the treatment of ulcerative colitis mice induced with dextran sulfate sodium (DSS). Our results demonstrate that ginsenoside RT4 effectively reduced weight, shortening of colonic tract length, colonic bowel damage, and disease activity index (DAI) scores in DSS-induced colitis mice. Additionally, ginsenoside RT4 regulates miR-144-3p expression in DSS-induced colitis mice, and we further confirmed that the solute carrier family 7 member 11 (SLC7A11) was the target gene of miR-144-3p by database analysis. Finally, ginsenoside RT4 inhibits the activation of the miR-144-3p/SLC7A11 signaling pathway, which alleviates colitis. Ginsenoside RT4 significantly decreased the expression of pro-inflammatory cytokines TNF-α and IL-1β and increased the anti-inflammatory cytokine IL-10.

CONCLUSIONS

These findings suggest that ginsenoside RT4 may have therapeutic potential for treating ulcerative colitis by downregulating levels of miR-144-3p/SLC7A11 signaling pathway, which are expected to be useful in treating clinical ulcerative colitis.

Genetic Correlation of miRNA Polymorphisms and STAT3 Signaling Pathway with Recurrent Implantation Failure in the Korean Population

The growing prevalence of in vitro fertilization-embryo transfer procedures has resulted in an increased incidence of recurrent implantation failure (RIF), necessitating focused research in this area. STAT3, a key factor in maternal endometrial remodeling and stromal proliferation, is crucial for successful embryo implantation. While the relationship between STAT3 and RIF has been studied, the impact of single nucleotide polymorphisms (SNPs) in miRNAs, well-characterized gene expression modulators, on STAT3 in RIF cases remains uncharacterized. Here, we investigated 161 RIF patients and 268 healthy control subjects in the Korean population, analyzing the statistical association between miRNA genetic variants and RIF risk. We aimed to determine whether SNPs in specific miRNAs, namely miR-218-2 rs11134527 G>A, miR-34a rs2666433 G>A, miR-34a rs6577555 C>A, and miR-130a rs731384 G>A, were significantly associated with RIF risk. We identified a significant association between miR-34a rs6577555 C>A and RIF prevalence (implantation failure [IF] ≥ 2: adjusted odds ratio [AOR] = 2.264, 95% CI = 1.007-5.092, p = 0.048). These findings suggest that miR-34a rs6577555 C>A may contribute to an increased susceptibility to RIF. However, further investigations are necessary to elucidate the precise mechanisms underlying the role of miR-34a rs6577555 C>A in RIF. This study sheds light on the genetic and molecular factors underlying RIF, offering new avenues for research and potential advancements in the diagnosis and treatment of this complex condition.

Epigenetic inheritance of phenotypes associated with parental exposure to cocaine

Parental exposure to drugs of abuse induces changes in the germline that can be transmitted across subsequent generations, resulting in enduring effects on gene expression and behavior. This transgenerational inheritance involves a dynamic interplay of environmental, genetic, and epigenetic factors that impact an individual's vulnerability to neuropsychiatric disorders. This chapter aims to summarize recent research into the mechanisms underlying the inheritance of gene expression and phenotypic patterns associated with exposure to drugs of abuse, with an emphasis on cocaine. We will first define the epigenetic modifications such as DNA methylation, histone post-translational modifications, and expression of non-coding RNAs that are impacted by parental cocaine use. We will then explore how parental cocaine use induces heritable epigenetic changes that are linked to alterations in neural circuitry and synaptic plasticity within reward-related circuits, ultimately giving rise to potential behavioral vulnerabilities. This discussion will consider phenotypic differences associated with gestational as well as both maternal and paternal preconception drug exposure and will emphasize differences based on offspring sex. In this context, we explore the complex interactions between genetics, epigenetics, environment, and biological sex. Overall, this chapter consolidates the latest developments in the multigenerational effects and long-term consequences of parental substance abuse.

Casein kinase 1 and 2 phosphorylate Argonaute proteins to regulate miRNA-mediated gene silencing

MicroRNAs (miRNAs) together with Argonaute (AGO) proteins form the core of the RNA-induced silencing complex (RISC) to regulate gene expression of their target RNAs post-transcriptionally. Argonaute proteins are subjected to intensive regulation via various post-translational modifications that can affect their stability, silencing efficacy and specificity for targeted gene regulation. We report here that in Caenorhabditis elegans, two conserved serine/threonine kinases - casein kinase 1 alpha 1 (CK1A1) and casein kinase 2 (CK2) - regulate a highly conserved phosphorylation cluster of 4 Serine residues (S988:S998) on the miRNA-specific AGO protein ALG-1. We show that CK1A1 phosphorylates ALG-1 at sites S992 and S995, while CK2 phosphorylates ALG-1 at sites S988 and S998. Furthermore, we demonstrate that phospho-mimicking mutants of the entire S988:S998 cluster rescue the various developmental defects observed upon depleting CK1A1 and CK2. In humans, we show that CK1A1 also acts as a priming kinase of this cluster on AGO2. Altogether, our data suggest that phosphorylation of AGO within the cluster by CK1A1 and CK2 is required for efficient miRISC-target RNA binding and silencing.

RNA-based medicine: from molecular mechanisms to therapy

RNA-based therapeutics have the potential to revolutionize the treatment and prevention of human diseases. While early research faced setbacks, it established the basis for breakthroughs in RNA-based drug design that culminated in the extraordinarily fast development of mRNA vaccines to combat the COVID-19 pandemic. We have now reached a pivotal moment where RNA medicines are poised to make a broad impact in the clinic. In this review, we present an overview of different RNA-based strategies to generate novel therapeutics, including antisense and RNAi-based mechanisms, mRNA-based approaches, and CRISPR-Cas-mediated genome editing. Using three rare genetic diseases as examples, we highlight the opportunities, but also the challenges to wide-ranging applications of this class of drugs.

Effects of hsa_circ_0074854 on colorectal cancer progression, construction of a circRNA-miRNA-mRNA network, and analysis of immune infiltration

PURPOSE

Circular RNAs have been demonstrated to be closely associated with the onset and metastasis of colorectal cancer. However, the roles and clinical diagnostic value of most circRNAs in colorectal cancer remain unclear.

METHODS

We detected the differential expression of circRNAs in CRC tissues and cells and investigated their relationship in conjunction with clinical pathological features. Additionally, we performed cellular functional experiments in CRC cell lines to explore the functions of circRNAs. To further validate the potential ceRNA network, qPCR was performed to assess the expression of miRNA and mRNA in CRC cells after differential expression of circRNAs knockdown. Furthermore, database analysis was utilized to explore the relationship between the predicted mRNAs and immune infiltration in CRC.

RESULTS

Our research findings indicate a positive correlation between hsa_circ_0074854 expression and advanced clinical pathological features, as well as an unfavorable prognosis. Knockdown of hsa_circ_0074854 was observed to inhibit proliferation and migration capabilities of colorectal cancer cells, affecting the cell cycle progression, and simultaneously promoting apoptosis. A competing endogenous RNA mechanism may exist among circRNAs, miRNAs, and mRNAs. Furthermore, the expression of target genes displayed correlations with the abundance of certain immune cells.

CONCLUSION

We propose a novel ceRNA network and evaluate the interplay between target genes and immune cells, providing novel insights for the diagnosis and targeted therapy of CRC.

The SARS-CoV-2 protein NSP2 enhances microRNA-mediated translational repression

Viruses use microRNAs (miRNAs) to impair the host antiviral response and facilitate viral infection by expressing their own miRNAs or co-opting cellular miRNAs. miRNAs inhibit translation initiation of their target mRNAs by recruiting the GIGYF2-4EHP (or EIF4E2) translation repressor complex to the mRNA 5'-cap structure. We recently reported that the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-encoded non-structural protein 2 (NSP2) interacts with GIGYF2. This interaction is critical for blocking translation of the Ifnb1 mRNA that encodes the cytokine interferon β, and thereby impairs the host antiviral response. However, it is not known whether NSP2 also affects miRNA-mediated silencing. Here, we demonstrate the pervasive augmentation of miRNA-mediated translational repression of cellular mRNAs by NSP2. We show that NSP2 interacts with argonaute 2 (AGO2), the core component of the miRNA-induced silencing complex (miRISC), via GIGYF2 and enhances the translational repression mediated by natural miRNA-binding sites in the 3' untranslated region of cellular mRNAs. Our data reveal an additional layer of the complex mechanism by which SARS-CoV-2 and likely other coronaviruses manipulate the host gene expression program by co-opting the host miRNA-mediated silencing machinery.

The RNase III enzyme Dicer1 is essential for larval development in Bombyx mori

MicroRNAs (miRNAs) are important regulators of nearly all aspects of biological processes in eukaryotes. During the biogenesis of miRNAs, the RNase III enzyme Dicer processes double-strand precursor miRNAs into mature miRNAs and promotes the assembly of RNA-induced silencing complexes (RISCs). Dicer has been reported to participate in a wide range of physiological processes, including development and immunity, in some insect species. However, the physiological roles of Dicer in lepidopterans remain poorly understood. In this study, we investigated the function of Bombyx mori Dicer1. We first performed sequence alignment and found that the sequence of functional domains of Dicer1 are varied among Lepidoptera, Diptera, Coleoptera, Blattaria, and Orthoptera. Using a binary clustered regularly interspaced palindromic repeats (CRISPR) / CRISPR-associated protein 9 genome editing approach, we showed that BmDicer1 mutants have arrested development from the 3rd instar into the 4th instar. RNA sequencing analysis indicated that the defects in BmDicer1 mutants are due to dysregulation of genes that encode proteins involved in metabolism, protein degradation, absorption, and renin-angiotensin pathways. Analysis using quantitative real-time polymerase chain reaction showed that mutation of BmDicer1 altered expression of miRNAs and their target genes. Therefore, our study demonstrates the critical roles of BmDicer1 in miRNA biogenesis and larval development in silkworm.

Triple ligation-based formation of a G-quadruplex for simultaneous detection of multiple miRNAs

The simultaneous detection of multiple microRNAs (miRNA) is of great necessity but has not been extensively studied. This prompted our study, which involved the development of a triple ligation-based system for detecting three miRNAs at the same time. We designed a multi-ligation-padlock (MLP) probe that consists of three parts, each of which is complementary to two different miRNAs at the same time. In the presence of all three miRNAs, the probe becomes circularized, but in the absence of even one target, the probe remains linear. The first part of the MLP probe (MLP1) contains a T7 promoter part that can initiate RNA synthesis for any given target condition. However, it also includes a G-quadruplex complementary segment, which can only form a parallel RNA G-quadruplex through rolling circle transcription by the circularized template in the presence of all three targets. In this case, the application of our parallel G-quadruplex sensing fluorescent probe lutidine DESA (LutD) produces a strong signal. However, in the absence of any one of the targets, the RNA G-quadruplex cannot be formed and ultimately the LutD probe does not generate any signal. This difference in the signal intensity represents the presence or absence of all the target miRNAs. With our system, we were able to detect miRNA 21 at levels as low as 1.13 fM, miRNA 146a as low as 1.37 fM, and miRNA 25b as low as 1.51 fM within 45 minutes, confirming that our novel system can selectively and sensitively diagnose triple miRNAs.

Consequences of depleting TNRC6, AGO, and DROSHA proteins on expression of microRNAs

The potential for microRNAs (miRNAs) to regulate gene expression remains incompletely understood. DROSHA initiates the biogenesis of miRNAs while variants of Argonaute (AGO) and trinucleotide repeat containing six (TNRC6) family proteins form complexes with miRNAs to facilitate RNA recognition and gene regulation. Here we investigate the fate of miRNAs in the absence of these critical RNAi protein factors. Knockout of DROSHA expression reduces levels of some miRNAs annotated in miRBase but not others. The identity of miRNAs with reduced expression matches the identity of miRNAs previously identified by experimental approaches. The MirGeneDB resource offers the closest alignment with experimental results. In contrast, the loss of TNRC6 proteins had much smaller effects on miRNA levels. Knocking out AGO proteins, which directly contact the mature miRNA, decreased expression of the miRNAs most strongly associated with AGO2 as determined from enhanced crosslinking immunoprecipitation (AGO2-eCLIP). Evaluation of miRNA binding to endogenously expressed AGO proteins revealed that miRNA:AGO association was similar for AGO1, AGO2, AGO3, and AGO4. Our data emphasize the need to evaluate annotated miRNAs based on approximate cellular abundance, DROSHA-dependence, and physical association with AGO when forming hypotheses related to their function.

The lncRNA Malat1 Inhibits miR-15/16 to Enhance Cytotoxic T Cell Activation and Memory Cell Formation

Proper activation of cytotoxic T cells via the T cell receptor and the costimulatory receptor CD28 is essential for adaptive immunity against viruses, many intracellular bacteria and cancers. Through biochemical analysis of RNA:protein interactions, we uncovered a non-coding RNA circuit regulating activation and differentiation of cytotoxic T cells composed of the long non-coding RNA Malat1 (Metastasis Associated Lung Adenocarcinoma Transcript 1) and the microRNA family miR-15/16. miR-15/16 is a widely and highly expressed tumor suppressor miRNA family important for cell proliferation and survival. miR-15/16 also play important roles in T cell responses to viral infection, including the regulation of antigen-specific T cell expansion and T cell memory. Comparative Argonaute-2 high throughput sequencing of crosslinking immunoprecipitation (Ago2 HITS-CLIP, or AHC) combined with gene expression profiling in normal and miR-15/16-deficient T cells revealed a large network of several hundred direct miR-15/16 target mRNAs, many with functional relevance for T cell activation, survival and memory formation. Among these targets, the long non-coding RNA Malat1 contained the largest absolute magnitude miR-15/16-dependent AHC peak in T cells. This binding site was also among the strongest lncRNA:miRNA interactions detected in the T cell transcriptome. We used CRISPR targeting with homology directed repair to generate mice with a 5-nucleotide mutation in the miR-15/16 binding site in Malat1. This mutation interrupted Malat1:miR-15/16 interaction, and enhanced the repression of other miR-15/16 target genes, including CD28. Interrupting Malat1 interaction with miR-15/16 decreased cytotoxic T cell activation, including the expression of IL-2 and a broader CD28-responsive gene program. Accordingly, Malat1 mutation diminished memory cell persistence following LCMV Armstrong and Listeria monocytogenes infection. This study marks a significant advance in the study of long noncoding RNAs in the immune system by ascribing cell-intrinsic, sequence-specific in vivo function to Malat1. These findings have implications for T cell-mediated autoimmune diseases, antiviral and anti-tumor immunity, as well as lung adenocarcinoma and other malignancies where Malat1 is overexpressed.

Synonymous sites for accessibility around microRNA binding sites in bacterial spot and speck disease resistance genes of tomato

The major causes of mass tomato infections in both covered and open ground are agents of bacterial spot and bacterial speck diseases. MicroRNAs (miRNAs) are 16-21 nucleotides in length, non-coding RNAs that inhibit translation and trigger mRNA degradation. MiRNAs play a significant part in plant resistance to abiotic and biotic stresses by mediating gene regulation via post-transcriptional RNA silencing. In this study, we analyzed a collection of bacterial resistance genes of tomato and their binding sites for tomato miRNAs and Pseudomonas syringe pv. tomato miRNAs. Our study found that two genes, bacterial spot disease resistance gene (Bs4) and bacterial speck disease resistance gene (Prf), have a 7mer-m8 perfect seed match with miRNAs. Bs4 was targeted by one tomato miRNA (sly-miR9470-3p) and three Pseudomonas syringe pv. tomato miRNAs (PSTJ4_3p_27246, PSTJ4_3p_27246, and PSTJ4_3p_27246). Again, Prf gene was found to be targeted by two tomato miRNAs namely, sly-miR9469-5p and sly-miR9474-3p. The accessibility of the miRNA-target site and its flanking regions and the relationship between relative synonymous codon usage and tRNAs were compared. Strong access to miRNA targeting regions and decreased rate of translations suggested that miRNAs might be efficient in binding to their particular targets. We also found the existence of rare codons, which suggests that it could enhance miRNA targeting even more. The codon usage pattern analysis of the two genes revealed that both were AT-rich (Bs4 = 63.2%; Prf = 60.8%). We found a low codon usage bias in both genes, suggesting that selective restriction might regulate them. The silencing property of miRNAs would allow researchers to discover the involvement of plant miRNAs in pathogen invasion. However, the efficient validation of direct targets of miRNAs is an urgent need that might be highly beneficial in enhancing plant resistance to multiple pathogenic diseases.

Cumulative effects of weakly repressive regulatory regions in the 3' UTR maintain PD-1 expression homeostasis in mammals

PD-1 has become a common target for cancer treatment. However, the molecular regulation of PD-1 expression homeostasis remains unclear. Here we report the PD-1 3' UTR can dramatically repress gene expression via promoting mRNA decay. Deletion of the PD-1 3' UTR inhibits T cell activity and promotes T-ALL cell proliferation. Interestingly, the robust repression is attributable to cumulative effects of many weak regulatory regions, which we show together are better able to maintain PD-1 expression homeostasis. We further identify several RNA binding proteins (RBPs) that modulate PD-1 expression via the 3' UTR, including IGF2BP2, RBM38, SRSF7, and SRSF4. Moreover, despite rapid evolution, PD-1 3' UTRs are functionally conserved and strongly repress gene expression through many common RBP binding sites. These findings reveal a previously unrecognized mechanism of maintaining PD-1 expression homeostasis and might represent a general model for how small regulatory effects play big roles in regulation of gene expression and biology.

miRNAs as potential game-changers in bone diseases: Future medicinal and clinical uses

MicroRNAs (miRNAs), short, highly conserved non-coding RNA, influence gene expression by sequential mechanisms such as mRNA breakdown or translational repression. Many biological processes depend on these regulating substances, thus changes in their expression have an impact on the maintenance of cellular homeostasis and result in the emergence of a variety of diseases. Relevant studies have shown in recent years that miRNAs are involved in many stages of bone development and growth. Additionally, abnormal production of miRNA in bone tissues has been closely associated with the development of numerous bone disorders, such as osteonecrosis, bone cancer, and bone metastases. Many pathological processes, including bone loss, metastasis, the proliferation of osteosarcoma cells, and differentiation of osteoblasts and osteoclasts, are under the control of miRNAs. By bringing together the most up-to-date information on the clinical relevance of miRNAs in such diseases, this study hopes to further the study of the biological features of miRNAs in bone disorders and explore their potential as a therapeutic target.

Exogenous growth hormone administration during total sleep deprivation changed the microRNA-9 and dopamine D2 receptor expressions followed by improvement in the hippocampal synaptic potential, spatial cognition, and inflammation in rats

RATIONALE

Disorders caused by total sleep deprivation can be modulated by the administration of growth hormone, which could affect the expression of microRNA-9 and dopamine D2 receptor expressions followed by improvement in the hippocampal synaptic potential, spatial cognition, and inflammation in rats.

OBJECTIVES

The present study aimed to elucidate the putative effects of exogenous growth hormone (GH) against total sleep deprivation (TSD)-induced learning and memory dysfunctions and possible involved mechanisms.

METHODS

To induce TSD, rats were housed in homemade special cages equipped with stainless steel wire conductors to induce general and inconsistent TSD. They received a mild repetitive electric shock to their paws every 10 min for 21 days. GH (1 mg/kg, sc) was administered to adult young male rats once daily for 21-day-duration induction of TSD. Spatial learning and memory performance, inflammatory status, microRNA-9 (miR-9) expression, dopamine D2 receptor (DRD2) protein level, and hippocampal histological changes were assayed at scheduled times after TSD.

RESULTS

The results indicated that TSD impaired spatial cognition, increased TNF-α, decreased level of miR-9, and increased DRD2 levels. Treatment with exogenous GH improved spatial cognition, decreased TNF-α, increased level of miR-9, and decreased DRD2 levels after TSD.

CONCLUSIONS

Our findings suggest that GH may play a key role in the modulation of learning and memory disorders as well as the ameliorating abnormal DRD2-related functional disorders associated with miR-9 in TSD.

Tweaking the Small Non-Coding RNAs to Improve Desirable Traits in Plant

Plant transcriptome contains an enormous amount of non-coding RNAs (ncRNAs) that do not code for proteins but take part in regulating gene expression. Since their discovery in the early 1990s, much research has been conducted to elucidate their function in the gene regulatory network and their involvement in plants' response to biotic/abiotic stresses. Typically, 20-30 nucleotide-long small ncRNAs are a potential target for plant molecular breeders because of their agricultural importance. This review summarizes the current understanding of three major classes of small ncRNAs: short-interfering RNAs (siRNAs), microRNA (miRNA), and transacting siRNAs (tasiRNAs). Furthermore, their biogenesis, mode of action, and how they have been utilized to improve crop productivity and disease resistance are discussed here.

MiRNAs Overexpression and Their Role in Breast Cancer: Implications for Cancer Therapeutics

MicroRNAs have a plethora of roles in various biological processes in the cells and most human cancers have been shown to be associated with dysregulation of the expression of miRNA genes. MiRNA biogenesis involves two alternative pathways, the canonical pathway which requires the successful cooperation of various proteins forming the miRNA-inducing silencing complex (miRISC), and the non-canonical pathway, such as the mirtrons, simtrons, or agotrons pathway, which bypasses and deviates from specific steps in the canonical pathway. Mature miRNAs are secreted from cells and circulated in the body bound to argonaute 2 (AGO2) and miRISC or transported in vesicles. These miRNAs may regulate their downstream target genes via positive or negative regulation through different molecular mechanisms. This review focuses on the role and mechanisms of miRNAs in different stages of breast cancer progression, including breast cancer stem cell formation, breast cancer initiation, invasion, and metastasis as well as angiogenesis. The design, chemical modifications, and therapeutic applications of synthetic anti-sense miRNA oligonucleotides and RNA mimics are also discussed in detail. The strategies for systemic delivery and local targeted delivery of the antisense miRNAs encompass the use of polymeric and liposomal nanoparticles, inorganic nanoparticles, extracellular vesicles, as well as viral vectors and viruslike particles (VLPs). Although several miRNAs have been identified as good candidates for the design of antisense and other synthetic modified oligonucleotides in targeting breast cancer, further efforts are still needed to study the most optimal delivery method in order to drive the research beyond preclinical studies.

Modulation of MicroRNA Expression During In Vitro Chondrogenesis

Since their discovery in 1993, microRNAs (miRNAs) are now recognized as important epigenetic regulators of many mammalian cellular processes including proliferation, apoptosis, metabolism, and differentiation. These small non-coding RNAs function by interacting with specific regions in the 3'-untranslated region of mRNAs, thereby resulting in mRNA degradation or suppression of translation. Since miRNAs have the ability to target many mRNAs within a given cell type, a number of cellular pathways and networks may be regulated as a result. To study the function of miRNAs, a number of methods can be used to modulate their activity in cells such as synthetic mimics or antagomirs for short-term assays or viral-based approaches for longer-term experiments such as cell differentiation assays. In this chapter, we provide our methodology to constitutively overexpress a desired miRNA during in vitro chondrogenesis of human cartilage progenitor cells (CPCs). Specifically, we describe how we obtain CPCs from human articular cartilage specimens, how we generate and titrate lentivirus engineered to overexpress a precursor miRNA, how we transduce CPCs with lentivirus and differentiate them toward the chondrocyte lineage, and how we extract RNA and measure expression levels of the miRNA of interest during in vitro chondrogenesis. We also provide some data from our laboratory demonstrating that we can achieve and maintain miRNA overexpression for up to 14 days in cartilage pellet cultures. We predict that these lentiviral-based approaches will also be useful to study how miRNA modulation of progenitor cells affects cell differentiation and extracellular matrix production within three-dimensional biomaterial scaffolds.