Adaptive translational pausing is a hallmark of the cellular response to severe environmental stress.

To survive, mammalian cells must adapt to environmental challenges. While the cellular response to mild stress has been widely studied, how cells respond to severe stress remains unclear. We show here that under severe hyperosmotic stress, cells enter a transient hibernation-like state in anticipation of recovery. We demonstrate this adaptive pausing response (APR) is a coordinated cellular response that limits ATP supply and consumption through mitochondrial fragmentation and widespread pausing of mRNA translation. This pausing is accomplished by ribosome stalling at translation initiation codons, which keeps mRNAs poised to resume translation upon recovery. We further show that recovery from severe stress involves ISR (integrated stress response) signaling that permits cell cycle progression, resumption of growth, and reversal of mitochondria fragmentation. Our findings indicate that cells can respond to severe stress via a hibernation-like mechanism that preserves vital elements of cellular function under harsh environmental conditions.

Dynamic Recruitment of Single RNAs to Processing Bodies Depends on RNA Functionality.

Cellular RNAs often colocalize with cytoplasmic, membrane-less ribonucleoprotein (RNP) granules enriched for RNA-processing enzymes, termed processing bodies (PBs). Here we track the dynamic localization of individual miRNAs, mRNAs, and long non-coding RNAs (lncRNAs) to PBs using intracellular single-molecule fluorescence microscopy. We find that unused miRNAs stably bind to PBs, whereas functional miRNAs, repressed mRNAs, and lncRNAs both transiently and stably localize within either the core or periphery of PBs, albeit to different extents. Consequently, translation potential and 3' versus 5' placement of miRNA target sites significantly affect the PB localization dynamics of mRNAs. Using computational modeling and supporting experimental approaches, we show that partitioning in the PB phase attenuates mRNA silencing, suggesting that physiological mRNA turnover occurs predominantly outside of PBs. Instead, our data support a PB role in sequestering unused miRNAs for surveillance and provide a framework for investigating the dynamic assembly of RNP granules by phase separation at single-molecule resolution.

eIF4E1b is a non-canonical eIF4E protecting maternal dormant mRNAs.

Maternal mRNAs are essential for protein synthesis during oogenesis and early embryogenesis. To adapt translation to specific needs during development, maternal mRNAs are translationally repressed by shortening the polyA tails. While mRNA deadenylation is associated with decapping and degradation in somatic cells, maternal mRNAs with short polyA tails are stable. Here we report that the germline-specific eIF4E paralog, eIF4E1b, is essential for zebrafish oogenesis. eIF4E1b localizes to P-bodies in zebrafish embryos and binds to mRNAs with reported short or no polyA tails, including histone mRNAs. Loss of eIF4E1b results in reduced histone mRNA levels in early gonads, consistent with a role in mRNA storage. Using mouse and human eIF4E1Bs (in vitro) and zebrafish eIF4E1b (in vivo), we show that unlike canonical eIF4Es, eIF4E1b does not interact with eIF4G to initiate translation. Instead, eIF4E1b interacts with the translational repressor eIF4ENIF1, which is required for eIF4E1b localization to P-bodies. Our study is consistent with an important role of eIF4E1b in regulating mRNA dormancy and provides new insights into fundamental post-transcriptional regulatory principles governing early vertebrate development.

The multifaceted effects of YTHDC1-mediated nuclear m6A recognition.

N6-methyladenosine or m6A modification to mRNAs is now recognised as a key regulator of gene expression and protein translation. The fate of m6A-modified mRNAs is decoded by m6A readers, mostly found in the cytoplasm, except for the nuclear-localised YTHDC1. While earlier studies have implicated YTHDC1-m6A functions in alternative splicing and mRNA export, recent literature has expanded its close association to the chromatin-associated, noncoding and regulatory RNAs to fine-tune transcription and gene expression in cells. Here, we summarise current progress in the study of YTHDC1 function in cells, highlighting its multiple modes of action in regulating gene expression, and propose the formation of YTHDC1 nuclear condensates as a general mechanism that underlies its diverse functions in the nucleus.

Circular mRNA-based TCR-T offers a safe and effective therapeutic strategy for treatment of cytomegalovirus infection.

Circular mRNA (cmRNA) is particular useful due to its high resistance to degradation by exonucleases, resulting in greater stability and protein expression compared to linear mRNA. T cell receptor (TCR)-engineered T cells (TCR-T) represent a promising means of treating viral infections and cancer. This study aimed to evaluate the feasibility and efficacy of cmRNA in antigen-specific-TCR discovery and TCR-T therapy. Using human cytomegalovirus (CMV) pp65 antigen as a model, we found that the expansion of pp65-responsive T cells was induced more effectively by monocyte-derived dendritic cells transfected with pp65-encoding cmRNA compared with linear mRNA. Subsequently, we developed cmRNA-transduced pp65-TCR-T (cm-pp65-TCR-T) that specifically targets the CMV-pp65 epitope. Our results showed that pp65-TCR could be expressed on primary T cells for more than 7 days. Moreover, both in vitro killing and in vivo CDX models demonstrated that cm-pp65-TCR-T cells specifically and persistently kill pp65-and HLA-expressing tumor cells, significantly prolonging the survival of mice. Collectively, our results demonstrated that cmRNA can be used as a more effective technical approach for antigen-specific TCR isolation and identification, and cm-pp65-TCR-T may provide a safe, non-viral, non-integrated therapeutic approach for controlling CMV infection, particularly in patients who have undergone allogeneic hematopoietic stem cell transplantation.

Autogenous Control of 5'TOP mRNA Stability by 40S Ribosomes.

Ribosomal protein (RP) expression in higher eukaryotes is regulated translationally through the 5'TOP sequence. This mechanism evolved to more rapidly produce RPs on demand in different tissues. Here we show that 40S ribosomes, in a complex with the mRNA binding protein LARP1, selectively stabilize 5'TOP mRNAs, with disruption of this complex leading to induction of the impaired ribosome biogenesis checkpoint (IRBC) and p53 stabilization. The importance of this mechanism is underscored in 5q− syndrome, a macrocytic anemia caused by a large monoallelic deletion, which we found to also encompass the LARP1 gene. Critically, depletion of LARP1 alone in human adult CD34+ bone marrow precursor cells leads to a reduction in 5'TOP mRNAs and the induction of p53. These studies identify a 40S ribosome function independent of those in translation that, with LARP1, mediates the autogenous control of 5'TOP mRNA stability, whose disruption is implicated in the pathophysiology of 5q− syndrome.

Key mRNAs and lncRNAs of pituitary that affect the reproduction of FecB + + small tail han sheep.

BACKGROUND: The pituitary directly regulates the reproductive process through follicle-stimulating hormone (FSH) and luteinizing hormone (LH). Transcriptomic research on the pituitaries of ewes with different FecB (fecundity Booroola) genotypes has shown that some key genes and lncRNAs play an important role in pituitary function and sheep fecundity. Our previous study found that ewes with FecB + + genotypes (without FecB mutation) still had individuals with more than one offspring per birth. It is hoped to analyze this phenomenon from the perspective of the pituitary transcriptome. RESULTS: The 12 Small Tail Han Sheep were equally divided into polytocous sheep in the follicular phase (PF), polytocous sheep in the luteal phase (PL), monotocous sheep in the follicular phase (MF), and monotocous sheep in the luteal phase (ML). Pituitary tissues were collected after estrus synchronous treatment for transcriptomic analysis. A total of 384 differentially expressed genes (DEGs) (182 in PF vs. MF and 202 in PL vs. ML) and 844 differentially expressed lncRNAs (DELs) (427 in PF vs. MF and 417 in PL vs. ML) were obtained from the polytocous-monotocous comparison groups in the two phases. Functional enrichment analysis showed that the DEGs in the two phases were enriched in signaling pathways known to play an important role in sheep fecundity, such as calcium ion binding and cAMP signaling pathways. A total of 1322 target relationship pairs (551 pairs in PF vs. MF and 771 pairs in PL vs. ML) were obtained for the target genes prediction of DELs, of which 29 DEL-DEG target relationship pairs (nine pairs in PF vs. MF and twenty pairs in PL vs. ML). In addition, the competing endogenous RNA (ceRNA) networks were constructed to explore the regulatory relationships of DEGs, and some important regulatory relationship pairs were obtained. CONCLUSION: According to the analysis results, we hypothesized that the pituitary first receives steroid hormone signals from the ovary and uterus and that VAV3 (Vav Guanine Nucleotide Exchange Factor 3), GABRG1 (Gamma-Aminobutyric Acid A Receptor, Gamma 1), and FNDC1 (Fibronectin Type III Domain Containing 1) played an important role in this process. Subsequently, the reproductive process was regulated by gonadotropins, and IGFBP1 (Insulin-like Growth Factor Binding Protein 1) was directly involved in this process, ultimately affecting litter size. In addition, TGIF1 (Transforming Growth Factor-Beta-Induced Factor 1) and TMEFF2 (Transmembrane Protein With EGF Like And Two Follistatin Like Domains 2) compensated for the effect of the FecB mutation and function by acting on TGF-ß/SMAD signaling pathway, an important pathway for sheep reproduction. These results provided a reference for understanding the mechanism of multiple births in Small Tail Han Sheep without FecB mutation.

Uncovering the potential molecular mechanism of liraglutide to alleviate the effects of high glucose on myoblasts based on high-throughput transcriptome sequencing technique.

BACKGROUND: Myoblasts play an important role in muscle growth and repair, but the high glucose environment severely affects their function. The purpose of this study is to explore the potential molecular mechanism of liraglutide in alleviating the effects of high glucose environments on myoblasts. METHODS: MTT, western blot, and ELISA methods were used to investigate the role of liraglutide on C2C12 myoblasts induced by high glucose. The high-throughput transcriptome sequencing technique was used to sequence C2C12 myoblasts from different treated groups. The DESeq2 package was used to identify differentially expressed-mRNAs (DE-mRNAs). Then, functional annotations and alternative splicing (AS) were performed. The Cytoscape-CytoHubba plug-in was used to identify multicentric DE-mRNAs. RESULTS: The MTT assay results showed that liraglutide can alleviate the decrease of myoblasts viability caused by high glucose. Western blot and ELISA tests showed that liraglutide can promote the expression of AMPKα and inhibit the expression of MAFbx, MuRF1 and 3-MH in myoblasts. A total of 15 multicentric DE-mRNAs were identified based on the Cytoscape-CytoHubba plug-in. Among them, Top2a had A3SS type AS. Functional annotation identifies multiple signaling pathways such as metabolic pathways, cytokine-cytokine receptor interaction, cAMP signaling pathway and cell cycle. CONCLUSION: Liraglutide can alleviate the decrease of cell viability and degradation of muscle protein caused by high glucose, and improves cell metabolism and mitochondrial activity. The molecular mechanism of liraglutide to alleviate the effect of high glucose on myoblasts is complex. This study provides a theoretical basis for the clinical effectiveness of liraglutide in the treatment of skeletal muscle lesions in diabetes.

Nonsense-mediated mRNA decay of metal-binding activator MAC1 is dependent on copper levels and 3'-UTR length in Saccharomyces cerevisiae.

The nonsense-mediated mRNA decay (NMD) pathway was initially identified as a surveillance pathway that degrades mRNAs containing premature termination codons (PTCs). NMD is now also recognized as a post-transcriptional regulatory pathway that regulates the expression of natural mRNAs. Earlier studies demonstrated that regulation of functionally related natural mRNAs by NMD can be differential and condition-specific in Saccharomyces cerevisiae. Here, we investigated the regulation of MAC1 mRNAs by NMD in response to copper as well as the role the MAC1 3'-UTR plays in this regulation. MAC1 is a copper-sensing transcription factor that regulates the high-affinity copper uptake system. MAC1 expression is activated upon copper deprivation. We found that MAC1 mRNAs are regulated by NMD under complete minimal (CM) but escaped NMD under low and high copper conditions. Mac1 protein regulated gene, CTR1 is not regulated by NMD in conditions where MAC1 mRNAs are NMD sensitive. We also found that the MAC1 3'-UTR is the NMD targeting feature on the mRNAs, and that MAC1 mRNAs lacking 3'-UTRs were stabilized during copper deprivation. Our results demonstrate a mechanism of regulation for a metal-sensing transcription factor, at both the post-transcriptional and post-translational levels, where MAC1 mRNA levels are regulated by NMD and copper, while the activity of Mac1p is controlled by copper levels.

Integration analysis of miRNA-mRNA pairs between two contrasting genotypes reveals the molecular mechanism of jujube (Ziziphus jujuba Mill.) response to high-temperature stress.

With global warming, high temperature (HT) has become one of the most common abiotic stresses resulting in significant crop yield losses, especially for jujube (Ziziphus jujuba Mill.), an important temperate economic crop cultivated worldwide. This study aims to explore the coping mechanism of jujube to HT stress at the transcriptional and post-transcriptional levels, including identifying differentially expressed miRNAs and mRNAs as well as elucidating the critical pathways involved. High-throughput sequencing analyses of miRNA and mRNA were performed on jujube leaves, which were collected from "Fucumi" (heat-tolerant) and "Junzao" (heat-sensitive) cultivars subjected to HT stress (42 °C) for 0, 1, 3, 5, and 7 days, respectively. The results showed that 45 known miRNAs, 482 novel miRNAs, and 13,884 differentially expressed mRNAs (DEMs) were identified. Among them, integrated analysis of miRNA target genes prediction and mRNA-seq obtained 1306 differentially expressed miRNAs-mRNAs pairs, including 484, 769, and 865 DEMIs-DEMs pairs discovered in "Fucuimi", "Junzao" and two genotypes comparative groups, respectively. Furthermore, functional enrichment analysis of 1306 DEMs revealed that plant-pathogen interaction, starch and sucrose metabolism, spliceosome, and plant hormone signal transduction were crucial pathways in jujube leaves response to HT stress. The constructed miRNA-mRNA network, composed of 20 DEMIs and 33 DEMs, displayed significant differently expressions between these two genotypes. This study further proved the regulatory role of miRNAs in the response to HT stress in plants and will provide a theoretical foundation for the innovation and cultivation of heat-tolerant varieties.

RNA-Seq analysis of long non-coding RNA in human intestinal epithelial cells infected by Shiga toxin-producing Escherichia coli.

BACKGROUND: The Shiga toxin-producing Escherichia coli (STEC) infects animals and induces acute intestinal inflammation. Long non-coding RNAs (lncRNAs) are known to play crucial roles in modulating inflammation response. However, it is not clear whether lncRNAs are involved in STEC-induced inflammation. METHODS AND RESULTS: To understand the association of lncRNAs with STEC infection, we used RNA-seq technology to analyze the profiles of lncRNAs in Mock-infected and STEC-infected human intestinal epithelial cells (HIECs). We detected a total of 702 lncRNAs differentially expressed by STEC infection. 583 differentially expressed lncRNAs acted as competitive microRNAs (miRNAs) binding elements in regulating the gene expression involved in TNF signaling pathway, IL-17 signaling pathway, PI3K-Akt signaling pathway, and apoptosis pathways. We analyzed 3 targeted genes, TRADD, TRAF1 and TGFB2, which were differentially regulated by mRNA-miRNA-lncRNA interaction network, potentially involved in the inflammatory and apoptotic response to STEC infection. Functional analysis of up/downstream genes associated with differentially expressed lncRNAs revealed their role in adheres junction and endocytosis. We also used the qRT-PCR technique to validate 8 randomly selected differentially expressed lncRNAs and mRNAs in STEC-infected HIECs. CONCLUSION: Our results, for the first time, revealed differentially expressed lncRNAs induced by STEC infection of HIECs. The results will help investigate the molecular mechanisms for the inflammatory responses induced by STEC.

Cordycepin delays postovulatory aging of oocytes through inhibition of maternal mRNAs degradation via DCP1A polyadenylation suppression.

Postovulatory aging leads to the decline in oocyte quality and subsequent impairment of embryonic development, thereby reducing the success rate of assisted reproductive technology (ART). Potential preventative strategies preventing oocytes from aging and the associated underlying mechanisms warrant investigation. In this study, we identified that cordycepin, a natural nucleoside analogue, promoted the quality of oocytes aging in vitro, as indicated by reduced oocyte fragmentation, improved spindle/chromosomes morphology and mitochondrial function, as well as increased embryonic developmental competence. Proteomic and RNA sequencing analyses revealed that cordycepin inhibited the degradation of several crucial maternal proteins and mRNAs caused by aging. Strikingly, cordycepin was found to suppress the elevation of DCP1A protein by inhibiting polyadenylation during postovulatory aging, consequently impeding the decapping of maternal mRNAs. In humans, the increased degradation of DCP1A and total mRNA during postovulatory aging was also inhibited by cordycepin. Collectively, our findings demonstrate that cordycepin prevents postovulatory aging of mammalian oocytes by inhibition of maternal mRNAs degradation via suppressing polyadenylation of DCP1A mRNA, thereby promoting oocyte developmental competence.

Drug-Resistant Epithelial Ovarian Cancer: Current and Future Perspectives.

Epithelial ovarian cancer (EOC) is a complex disease with diverse histological subtypes, which, based on the aggressiveness and course of disease progression, have recently been broadly grouped into type I (low-grade serous, endometrioid, clear cell, and mucinous) and type II (high-grade serous, high-grade endometrioid, and undifferentiated carcinomas) categories. Despite substantial differences in pathogenesis, genetics, prognosis, and treatment response, clinical diagnosis and management of EOC remain similar across the subtypes. Debulking surgery combined with platinum-taxol-based chemotherapy serves as the initial treatment for High Grade Serous Ovarian Carcinoma (HGSOC), the most prevalent one, and for other subtypes, but most patients exhibit intrinsic or acquired resistance and recur in short duration. Targeted therapies, such as anti-angiogenics (e.g., bevacizumab) and PARP inhibitors (for BRCA-mutated cancers), offer some success, but therapy resistance, through various mechanisms, poses a significant challenge. This comprehensive chapter delves into emerging strategies to address these challenges, highlighting factors like aberrant miRNAs, metabolism, apoptosis evasion, cancer stem cells, and autophagy, which play pivotal roles in mediating resistance and disease relapse in EOC. Beyond standard treatments, the focus of this study extends to alternate targeted agents, including immunotherapies like checkpoint inhibitors, CAR T cells, and vaccines, as well as inhibitors targeting key oncogenic pathways in EOC. Additionally, this chapter covers disease classification, diagnosis, resistance pathways, standard treatments, and clinical data on various emerging approaches, and advocates for a nuanced and personalized approach tailored to individual subtypes and resistance mechanisms, aiming to enhance therapeutic outcomes across the spectrum of EOC subtypes.

Gender associations between phthalate exposure and biomarkers of oxidative stress: A prospective cohort study.

Previous epidemiologic research has shown that phthalate exposure in pregnant women is related to adverse birth outcomes in a sex-specific manner. However, the biological mechanism of phthalate exposure that causes these birth outcomes remains poorly defined. In this research, we investigated the association between phthalate exposure and placental oxidative stress in a large population-based cohort study, aiming to initially explore the relationship between phthalate exposure and gene expression in placental oxidative stress in a sex-specific manner. Quantitative PCR was performed to measure the expression of placental inflammatory mRNAs (HO-1, HIF1α, and GRP78) in 2469 placentae. The multiple linear regression models were used to investigate the associations between mRNA and urinary phthalate monoesters. Phthalate metabolites monomethyl phthalate (MMP) and mono-n-butyl phthalate (MBP) were positively correlated with higher HIF1α expression in placentae of male fetuses (p < .05). Mono-benzyl phthalate (MBzP) increased the expression of HO-1, HIF1α, and GRP78 in placentae of male fetuses, and mono-(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP) up-regulated the expression of HIF1α and GRP78. Additionally, mono-(2-ethyl-5-oxohexyl) phthalate (MEOHP) was negatively correlated with HO-1, HIF1α, and GRP78 in placentae of female fetuses. Maternal phthalate exposure was associated with oxidative stress variations in placental tissues. The associations were closer in the placentas of male fetuses than in that of female ones. The placenta oxidative stress is worth further investigation as a potential mediator of maternal exposure-induced disease risk in children.

Gene Expression Profiling of Post Mortem Midbrain of Parkinson's Disease Patients and Healthy Controls.

Parkinson's disease (PD) stands as the most prevalent degenerative movement disorder, marked by the degeneration of dopaminergic neurons in the substantia nigra of the midbrain. In this study, we conducted a transcriptome analysis utilizing post mortem mRNA extracted from the substantia nigra of both PD patients and healthy control (CTRL) individuals. Specifically, we acquired eight samples from individuals with PD and six samples from CTRL individuals, with no discernible pathology detected in the latter group. RNA sequencing was conducted using the TapeStation 4200 system from Agilent Technologies. A total of 16,148 transcripts were identified, with 92 mRNAs displaying differential expression between the PD and control groups. Specifically, 33 mRNAs were significantly up-regulated, while 59 mRNAs were down-regulated in PD compared to the controls. The identification of statistically significant signaling pathways, with an adjusted p-value threshold of 0.05, unveiled noteworthy insights. Specifically, the enriched categories included cardiac muscle contraction (involving genes such as ATPase Na+/K+ transporting subunit beta 2 (ATP1B2), solute carrier family 8 member A1 (SLC8A1), and cytochrome c oxidase subunit II (COX2)), GABAergic synapse (involving GABA type A receptor-associated protein-like 1 (GABARAPL1), G protein subunit beta 5 (GNB5), and solute carrier family 38 member 2 (SLC38A2), autophagy (involving GABARAPL1 and tumor protein p53-inducible nuclear protein 2 (TP53INP2)), and Fc gamma receptor (FcγR) mediated phagocytosis (involving amphiphysin (AMPH)). These findings uncover new pathophysiological dimensions underlying PD, implicating genes associated with heart muscle contraction. This knowledge enhances diagnostic accuracy and contributes to the advancement of targeted therapies.

RNA landscapes of brain and brain-derived extracellular vesicles in simian immunodeficiency virus (SIV) infection and central nervous system pathology.

INTRODUCTION: Brain tissue-derived extracellular vesicles (bdEVs) act locally in the central nervous system (CNS) and may indicate molecular mechanisms in HIV CNS pathology. Using brain homogenate (BH) and bdEVs from a simian immunodeficiency virus (SIV) model of HIV disease, we identified RNA networks in SIV infection and neuroinflammation. METHODS: Postmortem occipital cortex samples were obtained from uninfected controls and SIV-infected subjects (acute and chronic phases with or without CNS pathology (SIV encephalitis). bdEVs were separated and characterized per international consensus guidelines. RNAs from bdEVs and BH were sequenced and qPCR-amplified to detect levels of small RNAs (sRNAs, including microRNAs (miRNAs)) and longer RNAs including messenger RNAs (mRNAs) and circular RNAs (circRNAs). RESULTS: Dysregulated RNAs in BH and bdEVs were identified in acute and chronic infection with pathology groups, including mRNAs, miRNAs, and circRNAs. Most dysregulated mRNAs in bdEVs reflected dysregulation in source BH. These mRNAs are disproportionately involved in inflammation and immune responses. Based on target prediction, several circRNAs that were differentially abundant in source tissue might be responsible for specific differences in sRNA levels in bdEVs during SIV infection. CONCLUSIONS: RNA profiling of bdEVs and source tissues reveals potential regulatory networks in SIV infection and SIV-related CNS pathology.

Comprehensive analysis of mRNAs in the cerebral cortex in APP/PS1 double-transgenic mice with Alzheimer's disease based on high-throughput sequencing of N4-acetylcytidine.

N4-acetylcytidine (ac4C), a significant modified nucleoside, participates in the development of many diseases. Messenger RNAs (mRNAs) contain most of the information of the genome and are the molecules that transmit information from genes to proteins. Alzheimer's disease (AD) is a progressive neurodegenerative disease in which fibrillar amyloid plaques are present. However, it remains unknown how mRNA ac4C modification affects the development of AD. In the current study, ac4C-modified mRNAs were comprehensively analyzed in AD mice by ac4C-RIP-seq and RNA-seq. Next, a protein-protein interaction (PPI) network was constructed to examine the relationships between the genes with differential ac4C modification levels and their RNA expression levels. The differentially expressed genes (DEGs) acquired above were subjected to Gene Ontology (GO) enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis to further analyze the molecular mechanisms in AD. In total, 3312 significant ac4C peaks were found on 2512 mRNAs, 1241 of which were hyperacetylated and 1271 of which were hypoacetylated. In addition, 956 mRNAs with differential expression were found, including 520 upregulated mRNAs and 436 downregulated mRNAs. Overall, 134 mRNAs with simultaneous changes at the ac4C levels as well as RNA expression levels were identified via joint analysis. Then, through PPI network construction and functional enrichment analysis, 37 key mRNAs were screened, which were predominantly enriched in GABAergic synapses and the PI3K/AKT signaling pathway. The significant difference in the abundance of mRNA ac4C modification indicates that this modification is associated with AD progression, which may provide insight for more investigations of the potential mechanisms.

N6-Methyladenosine Methylation of mRNA in Cell Senescence.

Cell senescence is the growth arrest caused by the accumulation of irreparable cell damage, which is involved in physiological and pathological processes and regulated by the post-transcriptional level. This regulation is performed by transcriptional regulators and driven by aging-related small RNAs, long non-coding RNAs, and RNA-binding proteins. N6-methyladenosine (m6A) is the most common chemical modification in eukaryotic mRNA, which can enhance or reduce the binding of transcriptional regulators. Increasing studies have confirmed the crucial role of m6A in controlling mRNA in various physiological processes. Remarkably, recent reports have indicated that abnormal methylation of m6A-related RNA may affect cell senescence. In this review, we clarified the association between m6A modification and cell senescence and analyzed the limitations of the current research.

METTL3 and METTL14-mediated N6-methyladenosine modification promotes cell proliferation and invasion in a model of endometriosis.

RESEARCH QUESTION: Could METTL3 and METTL14-mediated N6-methyladenosine (m6A) modification play possible cooperative roles in pathogenesis and progression of endometriosis? DESIGN: An investigation into m6A methylation profiles and the roles of METTL3 and METTL14 in the m6A regulation and pathogenesis of endometriosis. The m6A methylation and mRNA levels in paired ectopic endometrium and eutopic endometrium were measured using m6A-mRNA epitranscriptomic microarrays. The functions of m6A methylation in mRNAs were predicted using bioinformatics analysis. The levels of m6A methyltransferases were detected using quantitative polymerase chain reaction. The role of METTL3 and METTL14 in endometriosis was explored using eutopic endometrium stromal cells. RESULTS: The m6A methylation levels were decreased in 1312 mRNAs and increased in 518 mRNAs; 1797 mRNAs were increased and 2580 mRNAs were reduced in the ectopic endometrium compared with the eutopic endometrium. Pathway analysis found that the genes with hypo-methylated m6A were significantly associated with important pathways in endometriosis, including oestrogen, Hippo, and PI3K-Akt signalling and cell-cell adhesion. Furthermore, METTL3 and METTL14 were downregulated in the ectopic endometrium compared with the eutopic endometrium (P < 0.001). Simultaneous METTL3 and METTL14 knockdown increased cell proliferation and invasion. CONCLUSION: Taken together, these data reveal a differential m6A epitranscriptomic pattern in endometriosis. The N6-methyladenosine modification mediated by METTL3 and METTL14 play a cooperative role in promoting cell proliferation and invasion in a model of endometriosis. Therefore, METTL3 and METTL14 may be a novel treatment target of the disease.

Possible role of translation in unfertilized sea urchin eggs.

Unfertilized eggs of animals contain maternal messenger RNAs (mRNAs) and proteins, which are required for the maintenance of metabolism and regulation of development during the initial stages of embryogenesis. Unfertilized eggs are transcriptionally and translationally quiescent. After fertilization, activated translation of maternal mRNAs is one of the major forces that direct the early stages of embryogenesis before activation of the zygotic genome. However, a low rate and level of protein synthesis have been detected in unfertilized sea urchin eggs indicating that translation is not completely inhibited. Analysis of translatomes of unfertilized eggs and early embryos detected three sets of maternal mRNAs translated either before or after fertilization, or both before and after fertilization. Proteins encoded by maternal mRNAs, which are translated in unfertilized eggs, perform many different functions required for homeostasis, fertilization, egg activation, and early development. This suggests that translation in unfertilized sea urchin eggs may be required to renew the pool of proteins involved in these processes. Thus, translation may be necessary to maintain the fertility and developmental potential of sea urchin eggs during the long-term storage of eggs in ovaries until spawning begins.