microRNA Function Research Articles

MiR-224-5p Contained in Urinary Extracellular Vesicles Regulates PD-L1 Expression by Inhibiting Cyclin D1 in Renal Cell Carcinoma Cells.

Simple SummaryThe detailed effects of abundant microRNAs contained in extracellular vesicles (EVs) on renal cell carcinoma (RCC) progression are still unclear. This study identified the overexpression of miR-224-5p in urinary EVs of RCC patients. miR-224-5p suppressed RCC cell proliferation and induced cell cycle arrest through inhibiting cyclin D1 expression. PD-L1 protein abundance was increased by miR-224-5p, and this regulation could be transmitted via EVs intercellularly. These findings may shed light on biomarker discovery for RCC immunotherapy.The abundant miRNAs in urinary extracellular vesicles (EVs) represent ideal reservoirs for biomarker discovery, especially in renal cell carcinoma (RCC). However, the content and biological functions of microRNAs contained in urinary EVs in RCC remain ambiguous. In this study, urinary EVs were isolated and characterized from RCC patients and healthy volunteers. Differentially expressed microRNAs in urinary EVs were screened by small RNA sequencing. The target gene and biological functions of selected microRNAs were investigated through multifaceted methods. Results indicated that miR-224-5p was significantly upregulated in urinary EVs of RCC patients compared to healthy volunteers. The overexpression of miR-224-5p inhibited RCC cell proliferation and induced cell cycle arrest. The gene CCND1 encoding cyclin D1 was identified as a direct target of miR-224-5p via prediction and validation. Moreover, the invasive and metastatic abilities of RCC cells were enhanced by miR-224-5p. Interestingly, miR-224-5p also increased the stability of PD-L1 protein by inhibiting CCND1. This effect could be transmitted via EVs and further promoted the resistance of RCC cells to T cell-dependent toxicity. In summary, urinary EVs containing miR-224-5p were identified as a potential biomarker in RCC. Regulation of PD-L1 protein expression by miR-224-5p through suppressing CCND1 elucidates new roles of miR-224-5p in RCC progression.

Evaluation of exosomal miRNAs as potential diagnostic biomarkers for acute myocardial infarction using next-generation sequencing.

BackgroundAcute myocardial infarction (AMI) is one of the most common global causes of death. Although considerable progress has been made in AMI diagnosis, there remains an urgent need for novel diagnostic biomarkers for its prevention and treatment. Functional exosomal microRNAs (miRNAs) are recognized as potential biomarkers in many diseases. This study’s objective was to identify specific plasma exosomal miRNAs with biomarker potential for early AMI detection.MethodsExosomes from the plasma of 26 coronary artery disease (CAD) patients, 55 AMI patients, and 37 healthy controls were isolated and characterized by transmission electron microcopy (TEM), western blotting, and nanoparticle tracking analysis (NTA). The miRNAs were purified from exosomes, and unique molecular identifier (UMI) small RNA sequencing was performed. The random forest (RF) model was trained to predict potential biomarkers.ResultsNTA demonstrated that nanoparticle concentration did not change after AMI, while nanoparticle size distribution significantly decreased. The CAD and AMI groups’ miRNA expression profiles significantly differed from the healthy group’s profile. The RF classifier could be used to distinguish the healthy group from the AMI group, but could not be used to distinguish the CAD group from the other groups, which caused a high classification error rate. Eighteen miRNAs were selected as biomarkers based on their RF classifier significance. The diagnostic accuracy of 18 miRNAs was evaluated using AUC values of 0.93, 0.87, and 0.75 to detect healthy controls, AMI, and CAD, respectively.ConclusionsNanoparticle diameter and the 18 miRNAs may serve as simple and accessible fingerprints for early AMI diagnosis.

SiRNA Specificity: RNAi Mechanisms and Strategies to Reduce Off-Target Effects.

Short interfering RNAs (siRNAs) are processed from long double-stranded RNA (dsRNA), and a guide strand is selected and incorporated into the RNA-induced silencing complex (RISC). Within RISC, a member of the Argonaute protein family directly binds the guide strand and the siRNA guides RISC to fully complementary sites on-target RNAs, which are then sequence-specifically cleaved by the Argonaute protein—a process commonly referred to as RNA interference (RNAi). In animals, endogenous microRNAs (miRNAs) function similarly but do not lead to direct cleavage of the target RNA but to translational inhibition followed by exonucleolytic decay. This is due to only partial complementarity between the miRNA and the target RNA. SiRNAs, however, can function as miRNAs, and partial complementarity can lead to miRNA-like off-target effects in RNAi applications. Since siRNAs are widely used not only for screening but also for therapeutics as well as crop protection purposes, such miRNA-like off-target effects need to be minimized. Strategies such as RNA modifications or pooling of siRNAs have been developed and are used to reduce off-target effects.

MiR‑106b‑5p targeting SIX1 inhibits TGF‑β1‑induced pulmonary fibrosis and epithelial‑mesenchymaltransition in asthma through regulation of E2F1.

Asthma is an inflammatory disease of the airways, characterized by lung eosinophilia, mucus hypersecretion by goblet cells and airway hyper-responsiveness to inhaled allergens. The present study aimed to identify the function of microRNA (miR/miRNA)-106b-5p in TGF-β1-induced pulmonary fibrosis and epithelial-mesenchymal transition (EMT) via targeting sine oculis homeobox homolog 1 (SIX1) through regulation of E2F transcription factor 1 (E2F1) in asthma. Asthmatic mouse models were induced with ovalbumin. miRNA expression was evaluated using reverse transcription-quantitative PCR. Transfection experiments using bronchial epithelial cells were performed to determine the target genes. A luciferase reporter assay system was applied to identify the target gene of miR-106b-5p. The present study revealed downregulated miR-106b-5p expression and upregulated SIX1 expression in asthmatic mice and TGF-β1-induced BEAS-2B cells. Moreover, miR-106b-5p overexpression inhibited TGF-β1-induced fibrosis and EMT in BEAS-2B cells, while miR-106b-5p-knockdown produced the opposite effects. Subsequently, miR-106b-5p was found to regulate SIX1 through indirect regulation of E2F1. Additionally, E2F1- and SIX1-knockdown blocked TGF-β1-induced fibrosis and EMT in BEAS-2B cells. In addition, miR-106b-5p negatively regulated SIX1 via E2F1 in BEAS-2B cells. The present study demonstrated that the miR-106b-5p/E2F1/SIX1 signaling pathway may provide potential therapeutic targets for asthma.

MicroRNA expression profiling after recurrent febrile seizures in rat and emerging role of miR-148a-3p/SYNJ1 axis

Febrile seizures (FSs) are common neurological disorders in both infants and children, although the precise underlying mechanism remains to be explored, especially in the expression pattern and function of microRNAs (miRNAs). In this report, we aimed to screen new potential miRNAs and examine the role of miR-148a-3p in hippocampal neurons in FS rats via Synaptojanin-1 (SYNJ1). Thirty rats were randomly divided into the normal and FS model groups, which were investigated by miRNA array. This process identified 31 differentially expressed (20 upregulated and 11 downregulated) miRNAs and potential miRNA target genes. In addition, hippocampal neurons were assigned into five groups for different transfections. Apoptosis was detected by TUNEL and flow cytometry. SYNJ1 was identified as a target gene of miR-148-3p. In vitro experiments revealed that inhibition of miR-148a-3p decreased neuronal cell apoptosis. Moreover, overexpression of miR-148a-3p resulted in activation of PI3K/Akt signaling pathway and the apoptosis of hippocampal neurons. MiR-148a-3p inhibitor could reverse the above events. Taken together, our data demonstrated that the hippocampal miRNA expression profiles of a rat model of FS provide a large database of candidate miRNAs and neuron-related target genes. Furthermore, miR-148a-3p acted as a apoptosis enhcaner via the activation of the SYNJ1/PI3K/Akt signaling pathway, highlighting a potential therapeutic target in the treatment of infants with hyperthermia-induced brain injury.

Regulatory Functions of MicroRNAs in Cancer Pathogenesis

MicroRNAs (miRNAs) are a large family of evolutionary conserved small non-coding RNA molecules that firstly discovered in 1993. They regulate gene expression of about 50% of protein-coding genes at the post-transcriptional level. MiRNAs can target numerous messenger RNAs and subsequent misexpression of them can affect many different signaling pathways. They are playing a pivotal role in cancer development by regulation of the genes expression which involved in the proliferation, survival, differentiation, apoptosis or metastasis of the cancer cells. Several treatment approaches such as inhibition of oncomiRs and restoration of tumor suppressor miRNAs have been established in certain types of cancers and some other miRNA-based strategies are in development for cancer prevention and treatment. Nowadays, cancer is the most important target of miRNA therapeutics and the specific mechanisms by which miRNA mediates cancer pathways needs more research and study

Up-regulation of the expressions of MiR-149-5p and MiR-99a-3p in exosome inhibits the progress of pituitary adenomas.

This study explored the function of microRNAs (miRNAs) in invasive pituitary adenomas (IPA), and developed a microRNA-exosome strategy for the disease treatment. Differentially expressed miRNAs and tumor-associated markers in IPA, non-invasive pituitary adenoma (NIPA), and rat pituitary adenoma cells were identified by bioinformatics analysis and qRT-PCR. Then, the cells were treated by miR-149-5p and miR-99a-3p mimics or inhibitors, or incubated with modified exosome with overexpressed or silenced miRNAs. The cell behaviors were analyzed by molecular experiments. Xenograft assays were constructed by injection of pituitary adenoma cells and exosome into NU/NU nude mice. Tumor size, weight, and expressions of markers related to miRNAs and angiogenesis were determined. Target genes for miR-99a-3p and miR-149 were predicted and verified by bioinformatics analysis and molecular experiments. Twenty differentially expressed miRNAs were identified, among which miR-99a-3p and miR-149 were inhibited in both pituitary adenoma cells and tissues significantly. Expressions of E-cadherin and p53 were down-regulated, while those of MMP-2, MMP-9, N-cadherin, Vimentin, and VEGF were up-regulated in pituitary adenoma cells and tissues, especially in IPA. Further experiments revealed that overexpressed miR-149 and miR-99a-3p inhibited the growth and metastasis of pituitary adenoma cells and tube formation of endothelial cells. MiR-149 and miR-99a-3p overexpressed by exosome showed similar suppressive effects on cell viability, metastasis, tube formation ability, in vivo tumor growth, and expressions of angiogenesis-related markers. Further analysis showed that NOVA1, DTL, and RAB27B were targeted by miR-99a-3p. This study found that overexpressed miR-149-5p and miR-99a-3p induced by exosome could suppress the progression of IPA. 1. MiR-149-5p and miR-99a-3p affect the expression of EMT- and ECM-related markers and tumor-related genes in rat pituitary adenoma cells treated with exosomes. 2. Exosome inhibited the tumor growth. 3. Overexpressed miR-149-5p and miR-99a-3p induced by exosome.

Revisiting the Warburg effect: historical dogma versus current understanding.

Contrary to Warburg's original thesis, accelerated aerobic glycolysis is not a primary, permanent and universal consequence of dysfunctional or impaired mitochondria compensating for poor ATP yield per mole of glucose. Instead, in most tumours the Warburg effect is an essential part of a 'selfish' metabolic reprogramming, which results from the interplay between (normoxic/hypoxic) hypoxia-inducible factor-1 (HIF-1) overexpression, oncogene activation (cMyc, Ras), loss of function of tumour suppressors (mutant p53, mutant phosphatase and tensin homologue (PTEN), microRNAs and sirtuins with suppressor functions), activated (PI3K-Akt-mTORC1, Ras-Raf-MEK-ERK-cMyc, Jak-Stat3) or deactivated (LKB1-AMPK) signalling pathways, components of the tumour microenvironment, and HIF-1 cooperation with epigenetic mechanisms. Molecular and functional processes of the Warburg effect include: (a) considerable acceleration of glycolytic fluxes; (b) adequate ATP generation per unit time to maintain energy homeostasis and electrochemical gradients; (c) backup and diversion of glycolytic intermediates facilitating the biosynthesis of nucleotides, non-essential amino acids, lipids and hexosamines; (d) inhibition of pyruvate entry into mitochondria; (e) excessive formation and accumulation of lactate, which stimulates tumour growth and suppression of anti-tumour immunity - in addition, lactate can serve as an energy source for normoxic cancer cells and drives malignant progression and resistances to conventional therapies; (f) cytosolic lactate being mainly exported through upregulated lactate-proton symporters (MCT4), working together with other H+ transporters, and carbonic anhydrases (CAII, CAIX), which hydrate CO2 from oxidative metabolism to form H+ and bicarbonate; (g) these proton export mechanisms, in concert with poor vascular drainage, being responsible for extracellular acidification, driving malignant progression and resistance to conventional therapies; (h) maintenance of the cellular redox homeostasis and low reactive oxygen species (ROS) formation; and (i) HIF-1 overexpression, mutant p53 and mutant PTEN, which inhibit mitochondrial biogenesis and functions, negatively impacting cellular respiration rate. The glycolytic switch is an early event in oncogenesis and primarily supports cell survival. All in all, the Warburg effect, i.e. aerobic glycolysis in the presence of oxygen and - in principle - functioning mitochondria, constitutes a major driver of the cancer progression machinery, resistance to conventional therapies, and poor patient outcome. However, as evidenced during the last two decades, in a minority of tumours primary mitochondrial defects can play a key role promoting the Warburg effect and tumour progression due to mutations in some Krebs cycle enzymes and mitochondrial ROS overproduction.

LncRNA NEAT1 regulates the proliferation and production of the inflammatory cytokines in rheumatoid arthritis fibroblast-like synoviocytes by targeting miR-204-5p.

Rheumatoid arthritis (RA) is a chronic inflammatory disease, featured by erosive arthritis, which will eventually lead to deprivation normal functions of the joint and joint malformations. Continued illness also results in more serious complications, such as cardiovascular diseases and disability. Long non-coding RNAs (lncRNAs) and microRNAs (miRNAs) function in various conditions, including RA. LncRNA NEAT1 was reported to promote migration and invasion in RA-FLSs, functioning as a promising diagnostic and therapeutic indicator in RA. The present work focused on the role of lncRNA NEAT1 in RA and the related mechanism. We collected the synovial tissue samples of 30 RA patients and 20 healthy controls. Moreover, RA fibroblast-like synoviocytes (RA-FLSs) cell line was bought and treated with tumor necrosis factor-α (TNF-α) to establish in vitro model of RA. Quantitative real-time polymerase chain reaction (qRT-PCR) was used to determine the expression of NEAT1 in synovial tissue and RA-FLSs. NEAT1 silencing plasmid were synthesized and co-trasnfected with miR-204-5p inhibitor into RA-FLSs. MTT and 5-Ethynyl-2'-deoxyuridine staining were used to assess cell proliferation. Flow cytometry and TUNEL assay were used to determine the cell apoptosis. miR-204-5p has been predicted as a target miRNA of NEAT1, and the interaction between NEAT1 and miR-204-5p was verified by dual-luciferase assay and RNA pull-down assay. qRT-PCR and enzyme-linked immunosorbent assay were used to determine the mRNA and protein concentration of interleukin-1β and interleukin-6. Finally, western blot assay was applied to measure the effect of NEAT1 and on p53, NF-κB, and p-NF-κB expressions. We found that NEAT1 was up-regulated, and miR-204-5p was down-regulated in the RA patients' synovial tissue and TNF-α treated RA-FLSs. TNF-α increased NEAT1 level and decreased miR-204-5p level in RA-FLSs. There was no significant variance of p53 after transfected with NEAT1 in RA-FLSs. Meanwhile, Knockdown of NEAT1 attenuated TNF-α-induced RA-FLSscellproliferation andinflammatory cytokine production while promoted cell apoptosis by targeting miR-204-5p through NF-κB pathway. These findings indicated that NEAT1 may be developed as a potential target for patients with RA.

Genome-Wide Identification of Copper Stress-Regulated and Novel MicroRNAs in Mulberry Leaf.

Copper (Cu) is an essential trace element for plant growth and development. It is widely involved in respiration, photosynthesis, pollen formation, and other biological processes. Therefore, low or excessive copper causes damage to plants. Mulberry is an essential perennial economic tree. At present, research on the abiotic stress responses in mulberry is mainly focused on the identification of resistant germplasm resources and cloning of resistant genes. In contrast, studies on the resistance function of microRNAs and the regulatory gene responses to stress are rare. In this study, small RNA libraries (control and copper stressed) were constructed from mulberry leaf RNA. High-throughput sequencing and screening were employed, a total of 65 known miRNAs and 78 predicted novel mature miRNAs were identified, among which 40 miRNAs were differentially expressed under copper stress. Subsequently, expression patterns were verified for 14 miRNAs by real-time fluorescence quantitative PCR (qPCR). The target genes of miRNAs were validated by 5' RLM-RACE. Our results provide the bases for further study on the molecular mechanism of copper stress regulation in mulberry.

The Functions of MicroRNAs and Their Potential Applications in the Diagnosis and Treatment of Gastric Cancer

The Functions of MicroRNAs and Their Potential Applications in the Diagnosis and Treatment of Gastric Cancer

MiR-146b-3p regulates proliferation of pancreatic cancer cells with stem cell-like properties by targeting MAP3K10.

Purpose: Cancer stem cells (CSCs) initiate and maintain tumorigenesis due to their unique pluripotency. However, pancreatic stem cell gene signatures are not completely revealed yet. Here, we isolated pancreatic cancer stem cells (P-CSCs) and exploited their distinct genome-wide mRNA and miRNA expression profiles using microarrays.Methods: CD24+ CD44+ ESA+ cells were isolated from two pancreatic xenograft cells by the flow cytometry and identified the stem cell-like properties by the tumor formation, self-renew and chemoresistance. Microarrays and qRT-PCR were used to exploit their distinct Genome-wide mRNA and miRNA expression profiles. The function and candidate target genes of key microRNA were detected after Ectopic restoration in the pancreatic cancer cell lines MIA Paca-2 (CSChigh) and BxPC-3 (CSClow).Results: In this study, we isolated P-CSCs from two xenografts cells. Genome-wide profiling experiments showed 479 genes and 15 microRNAs specifically expressed in the P-CSCs, including genes involved in TGF-β and p53 signaling pathways and particularly miR-146b-3p as the most significantly downregulated miRNA. We confirmed miR-146b-3p as a downregulated signature in pancreatic cancer tissues and cell line MIA Paca-2 (CSChigh) cells. Ectopic restoration of miR-146b-3p expression with pre-miR reduced cell proliferation, induced apoptosis, increased G1 phase and reduced S phase in cell cycle in MIA Paca-2 (CSChigh), but not in BxPC-3 (CSClow). Re-expression of miR-146b-3p with lentivirus significantly inhibited tumorigenicity in vivo in MIA Paca-2, but slightly in BxPC-3. Furthermore, we demonstrated that miR-146b-3p directly targeted MAP3K10 and might activate Hedgehog pathway as well through DYRK2 and GLI2.Conclusions: These results suggest that P-CSCs have distinct gene expression profiles. MiR-146b-3p inhibits proliferation and induced apoptosis in P-CSCs high cells lines by targeting MAP3K10. Targeting P-CSCs specific genes may provide novel strategies for therapeutic purposes.

Investigation of the efficacy of paclitaxel on some miRNAs profiles in breast cancer stem cells.

Understanding of the functions of microRNAs in breast cancer and breast cancer stem cells have been a hope for the development of new molecular targeted therapies. Here, it is aimed to investigate the differences in the expression levels of let-7a, miR-10b, miR-21, miR-125b, miR-145, miR-155, miR-200c, miR-221, miR-222 and miR-335, which associated with gene and proteins in MCF-7 (parental) and MCF-7s (Mammosphere/stem cell-enriched population/CD44+/CD24-cells) cells treated with paclitaxel. MCF-7s were obtained from parental MCF-7 cells. Cytotoxic activity of paclitaxel was determined by ATP assay. Total RNA isolation and cDNA conversion were performed from the samples. Changes in expression levels of miRNAs were examined by RT-qPCR. Identified target genes and proteins of miRNAs were analyzed with RT-qPCR and western blot analysis, respectively. miR-125b was significantly expressed (2.0946-fold; p = 0.021) in MCF-7s cells compared to control after treatment with paclitaxel. Downregulation of SMO, STAT3, NANOG, OCT4, SOX2, ERBB2 and ERBB3 and upregulation of TP53 genes were significant after 48 h treatment in MCF-7s cells. Protein expressions of SOX2, OCT4, SMAD4, SOX2 and OCT4 also decreased. Paclitaxel induces miR-125b expression in MCF-7s cells. Upregulation of miR-125b may be used as a biomarker for the prediction of response to paclitaxel treatment in breast cancer.

МикроРНК растений: Методы изучения и роль в развитии симбиозов с полезными микроорганизмами

MicroRNAs are small non-coding RNA molecules that act as post-transcriptional regulators of gene expression due to rather strict complementarity to their mRNA and have a length of 20-24 nucleotides. Plant microRNAs control a wide range of physiological processes, including nutrition, growth, resistance reactions and interaction with other organisms, via modulation of the expression of transcription factors, stress-induced proteins, hormone biosynthesis enzymes, and other genes. Legumes are able to form mutualistic symbioses simultaneously with nitrogen-fixing bacteria and arbuscular mycorrhiza. Both the early and late stages of these symbiosis are regulated by complex genetic mechanisms. As it has become known in recent years, one of these mechanisms is the regulation of gene expression by microRNA. The study of microRNAs is carried out by various methods, but over the past decade, next-generation sequencing (NGS) technologies have become the most popular approach in this field. NGS is used to identify conservative and novel microRNAs in the genomes of various organisms (both model and non-model), as well as to study the functioning of microRNAs in various experimental conditions with the additional use of transcriptome and degradome sequencing data. The article describes the main stages of working with microRNA sequencing data: quality control of reads (with a list of programs required at this stage), identification of conservative and novel microRNAs using miRDeep2 tool, search for targets of identified microRNAs using PAREsnip2, functional annotation of targets and the use of statistical tests for the analysis of functional enrichment, which facilitates the interpretation of the data obtained and allows us to make assumptions about the biological consequences of the activity of identified microRNAs in the object under study. This information may be useful for researchers who deal with microRNAs in silico for the first time or want to save time and resources on searching and analyzing information about the tools needed to work with microRNA sequencing data.

Bioinformatics Analysis Reveals Functions of MicroRNAs in Rice Under the Drought Stress

Background: Drought is one of the most damaging and widespread abiotic stresses that can severely limit the rice production. MicroRNAs (miRNAs) act as a promising tool for improving the drought tolerance of rice and have become a hot spot in recent years. Objective: In order to further extend the understanding of miRNAs, the functions of miRNAs in rice under drought stress are analyzed by bioinformatics. Method: In this study, we integrated miRNAs and genes transcriptome data of rice under the drought stress. Some bioinformatics methods were used to reveal the functions of miRNAs in rice under drought stress. These methods included target genes identification, differentially expressed miRNAs screening, enrichment analysis of DEGs, network constructions for miRNA-target and target-target proteins interaction. Results: (1) A total of 229 miRNAs with differential expression in rice under the drought stress, corresponding to 73 rice miRNAs families, were identified. (2) 1035 differentially expressed genes (DEGs) were identified, which included 357 up-regulated genes, 542 down-regulated genes and 136 up/down-regulated genes. (3) The network of regulatory relationships between 73 rice miRNAs families and 1035 DEGs was constructed. (4) 25 UP_KEYWORDS terms of DEGs, 125 GO terms and 7 pathways were obtained. (5) The protein-protein interaction network of 1035 DEGs was constructed. Conclusion: (1) MiRNA-regulated targets in rice might mainly involve in a series of basic biological processes and pathways under drought conditions. (2) MiRNAs in rice might play critical roles in Lignin degradation and ABA biosynthesis. (3) MiRNAs in rice might play an important role in drought signal perceiving and transduction.

Circular RNA as a novel molecular biomarker for radon-induced lung cancer

Circular (circ) RNAs are non-coding closed RNA molecules. Studies of human tumors, including lung cancer, have shown a change in the expression profile of circrna. CircRNA can indirectly regulate gene expression by binding and inhibiting microRNA functions. Thanks to this mechanism, circRNAs can regulate proliferation, apoptosis, invasion, and metastasis. In this review, we showed a brief description of the expression and function of circRNAs, as well as their roles in the development of lung cancer. We presented evidence that these molecules should be studied as useful biomarkers for radon-induced lung cancer.

Therapeutic effects and perspective of stem cell extracellular vesicles in aging and cancer.

Senescent cells can secrete a plethora of cytokines which induce senescent phenotype of neighboring cells and was called senescence-associated secretory phenotype. Previously, it was believed that cancer was caused by the infinite division and uncontrolled proliferation of cells. Based on this, anticancer treatments were all aimed at killing cancer cells. Cancer is now considered an age-related disease. Cancer cells are not exogenous, but one of the worst results of injuries which initially induce cell senescence. Therefore, reversing cell senescence can fundamentally prevent and treat cancer. Though current anticancer treatments induce the cancer cells apoptosis, they induce senescence of normal cells at the same time, thus promoting the occurrence and development of cancer and forming a vicious circle. Extracellular vesicles (EVs) are nano-sized vesicles which partially mirror their parent cells. In the tumor microenvironment, EVs of senescent cells can change the expression profile of cancer cells, contributing to their resistance to chemotherapy. There is growing evidence indicates that stem cell EVs exert effective antiaging and anticancer actions by transferring functional microRNAs and proteins. This review will summarize the therapeutic role of stem cell EVs in reversing aging and cancer, which suggests the broad clinical application perspective.

Premature MicroRNA-Based Therapeutic: A "One-Two Punch" against Cancers.

Simple SummaryThe current understanding of miRNA biology is greatly derived from studies on the guide strands and the passenger strands, also called miRNAs*, which are considered as carriers with no sense for long periods. As such, various studies alter the expression of guide strands by manipulating the expression of their primary transcripts or precursors, both of which are premature miRNAs. In this situation, the regulatory miRNA* species may interfere with the phenotypic interpretation against the target miRNA. However, such methods could manipulate the expression of two functionally synergistic miRNAs of the same precursor, leading to therapeutic potential against various diseases, including cancers. Premature miRNAs represent an underappreciated target reservoir and provide molecular targets for “one-two punch” against cancers. Examples of targetable miRNA precursors and available targeting strategies are provided in this review.Up-to-date knowledge regarding the biogenesis and functioning of microRNAs (miRNAs) has provided a much more comprehensive and concrete view of miRNA biology than anyone ever expected. Diverse genetic origins and biogenesis pathways leading to functional miRNAs converge on the synthesis of ≈21-nucleotide RNA duplex, almost all of which are processed from long premature sequences in a DICER- and/or DROSHA-dependent manner. Formerly, it was assumed that one mature strand of the duplex is preferentially selected for entry into the silencing complex, and the paired passenger strands (miRNA*) are subjected to degradation. However, given the consolidated evidence of substantial regulatory activity of miRNA* species, currently, this preconception has been overturned. Here, we see the caveat and opportunity toward exogenously manipulating the expression of premature miRNA, leading to simultaneous upregulation or downregulation of dual regulatory strands due to altered expressions. The caveat is the overlooked miRNA* interference while manipulating the expression of a target miRNA at the premature stage, wherein lies the opportunity. If the dual strands of a pre-miRNA function synergistically, the overlooked miRNA* interference may inversely optimize the therapeutic performance. Insightfully, targeting the premature miRNAs may serve as the “one-two punch” against diseases, especially cancers, and this has been discussed in detail in this review.

Ancient microRNA profiles of a 14,300-year-old canid samples confirm taxonomic origin and give glimpses into tissue-specific gene regulation from the Pleistocene.

DNA sequencing is the current key technology for historic or ancient biological samples and has led to many exciting discoveries in the field of paleogenomics. However, functional insights into tissue identity, cellular composition, or gene regulation cannot be gained from DNA. Recent analyses have shown that, under favorable conditions, RNA can also be sequenced from ancient samples, enabling studies at the transcriptomic and regulatory level. Analyzing ancient RNA data from a Pleistocene canid, we find hundreds of intact microRNAs that are taxonomically informative, show tissue specificity and have functionally predictive characteristics. With an extraordinary age of 14,300 yr, these microRNA sequences are by far the oldest ever reported. The authenticity of the sequences is further supported by (i) the presence of canid/Caniformia-specific sequences that never evolved outside of this clade, (ii) tissue-specific expression patterns (cartilage, liver, and muscle) that resemble those of modern dogs, and (iii) RNA damage patterns that are clearly distinct from those of fresh samples. By performing computational microRNA-target enrichment analyses on the ancient sequences, we predict microRNA functions consistent with their tissue pattern of expression. For instance, we find a liver-specific microRNA that regulates carbohydrate metabolism and starvation responses in canids. In summary, we show that straightforward paleotranscriptomic microRNA analyses can give functional glimpses into tissue identity, cellular composition, and gene regulatory activity of ancient samples and biological processes that took place in the Pleistocene, thus holding great promise for deeper insights into gene regulation in extinct animals based on ancient RNA sequencing.

MicroRNA function in craniofacial bone formation, regeneration and repair.

Bone formation in the craniofacial complex is regulated by cranial neural crest (CNC) and mesoderm-derived cells. Different elements of the developing skull, face, mandible, maxilla (jaws) and nasal bones are regulated by an array of transcription factors, signaling molecules and microRNAs (miRs). miRs are molecular modulators of these factors and act to restrict their expression in a temporal-spatial mechanism. miRs control the different genetic pathways that form the craniofacial complex. By understanding how miRs function in vivo during development they can be adapted to regenerate and repair craniofacial genetic anomalies as well as bone diseases and defects due to traumatic injuries. This review will highlight some of the new miR technologies and functions that form new bone or inhibit bone regeneration.