Behind the scenes: How RNA orchestrates the epigenetic regulation of gene expression

Epigenetic processes in insect adaptation to environmental stress

Insects exhibit remarkable adaptability to a wide range of environmental stressors, including temperature fluctuations, pathogens, and changes in diet. This adaptability is often driven by epigenetic processes, which regulate gene expression without altering the underlying DNA sequence. This review provides a comprehensive overview of these epigenetic processes in insect adaptation, highlighting their impact on development, behaviour, and stress resilience. Understanding these mechanisms is essential for pest management and conservation efforts, offering insights into the rapid adaptive capacity of insects. By examining recent studies on epigenetics in insects, we aim to elucidate the molecular underpinnings of their adaptation and suggest future research directions in this evolving field.

Exploring the methyl-verse: Dynamic interplay of epigenome and m6A epitranscriptome

The orchestration of dynamic epigenetic and epitranscriptomic modifications is pivotal for the fine-tuning of gene expression. However, these modifications are traditionally examined independently. Recent compelling studies have disclosed an interesting communication and interplay between m6A RNA methylation (m6A epitranscriptome) and epigenetic modifications, enabling the formation of feedback circuits and cooperative networks. Intriguingly, the interaction between m6A and DNA methylation machinery, coupled with the crosstalk between m6A RNA and histone modifications shape the transcriptional profile and translational efficiency. Moreover, m6A modifications interact also with non-coding RNAs, modulating their stability, abundance, and regulatory functions. In the light of these findings, m6A imprinting acts as a versatile checkpoint, linking epigenetic and epitranscriptomic layers toward a multilayer and time-dependent control of gene expression and cellular homeostasis. The scope of the present review is to decipher the m6A-coordinated circuits with DNA imprinting, chromatin architecture, and non-coding RNAs networks in normal physiology and carcinogenesis. Ultimately, we summarize the development of innovative CRISPR-dCas engineering platforms fused with m6A catalytic components (m6A writers or erasers) to achieve transcript-specific editing of m6A epitranscriptomes that can create new insights in modern RNA therapeutics.

Natural products and long noncoding RNA signatures in gallbladder cancer: a review focuses on pathogenesis, diagnosis, and drug resistance

Gallbladder cancer (GBC) is an aggressive and lethal malignancy with a poor prognosis. Long noncoding RNAs (lncRNAs) and natural products have emerged as key orchestrators of cancer pathogenesis through widespread dysregulation across GBC transcriptomes. Functional studies have revealed that lncRNAs interact with oncoproteins and tumor suppressors to control proliferation, invasion, metastasis, angiogenesis, stemness, and drug resistance. Curcumin, baicalein, oleanolic acid, shikonin, oxymatrine, arctigenin, liensinine, fangchinoline, and dioscin are a few examples of natural compounds that have demonstrated promising anticancer activities against GBC through the regulation of important signaling pathways. The lncRNAs, i.e., SNHG6, Linc00261, GALM, OIP5-AS1, FOXD2-AS1, MINCR, DGCR5, MEG3, GATA6-AS, TUG1, and DILC, are key players in regulating the aforementioned processes. For example, the lncRNAs FOXD2-AS1, DILC, and HOTAIR activate oncogenes such as DNMT1, Wnt/β-catenin, BMI1, and c-Myc, whereas MEG3 and GATA6-AS suppress the tumor proteins NF-κB, EZH2, and miR-421. Clinically, specific lncRNAs can serve as diagnostic or prognostic biomarkers based on overexpression correlating with advanced TNM stage, metastasis, chemoresistance, and poor survival. Therapeutically, targeting aberrant lncRNAs with siRNA or antisense oligos disrupts their oncogenic signaling and inhibits GBC progression. Overall, dysfunctional lncRNA regulatory circuits offer multiple avenues for precision medicine approaches to improve early GBC detection and overcome this deadly cancer. They have the potential to serve as novel biomarkers as they are detectable in bodily fluids and tissues. These findings enhance gallbladder treatments, mitigating resistance to chemo- and radiotherapy.

Emerging interactions between RNA methylation and chromatin architecture

Epitranscriptomics, the study of chemical modifications of RNA molecules, is increasingly recognized as an important component of gene expression regulation. While the majority of research has focused on N6-methyladenosine (m6A) RNA methylation on mRNAs, emerging evidence has revealed that the m6A modification extends beyond mRNAs to include chromatin-associated RNAs (caRNAs). CaRNAs constitute an important class of RNAs characterized by their interaction with the genome and epigenome. These features allow caRNAs to be actively involved in shaping genome organization. In this review, we bring into focus recent findings of the dynamic interactions between caRNAs and chromatin architecture and how RNA methylation impacts caRNAs' function in this interplay. We highlight several enabling techniques, which were critical for genome-wide profiling of caRNAs and their modifications. Given the nascent stage of the field, we emphasize on the need to address critical gaps in study of these modifications in more relevant biological systems. Overall, these exciting progress have expanded the scope and reach of epitranscriptomics, unveiling new mechanisms that underpin the control of gene expression and cellular phenotypes, with potential therapeutic implications.

Up-regulation of long non-coding RNA H19 ameliorates renal tubulointerstitial fibrosis by reducing lipid deposition and inflammatory response through regulation of the microRNA-130a-3p/long-chain acyl-CoA synthetase 1 axis

Long non-coding RNA (lncRNA) H19 is an extensively studied lncRNA that is related to numerous pathological changes. Our previous findings have documented that serum lncRNA H19 levels are decreased in patients with chronic kidney disorder and lncRNA H19 reduction is closely correlated with renal tubulointerstitial fibrosis, an essential step in developing end-stage kidney disease. Nonetheless, the precise function and mechanism of lncRNA H19 in renal tubulointerstitial fibrosis are not fully comprehended. The present work utilized a mouse model of unilateral ureteral obstruction (UUO) and transforming growth factor-β1 (TGF-β1)-stimulated HK-2 cells to investigate the possible role and mechanism of lncRNA H19 in renal tubulointerstitial fibrosis were investigated. Levels of lncRNA H19 decreased in kidneys of mice with UUO and HK-2 cells stimulated with TGF-β1. Up-regulation of lncRNA H19 in mouse kidneys remarkably relieved kidney injury, fibrosis and inflammation triggered by UUO. Moreover, the increase of lncRNA H19 in HK-2 cells reduced epithelial-to-mesenchymal transition (EMT) induced by TGF-β1. Notably, up-regulation of lncRNA H19 reduced lipid accumulation and triacylglycerol content in kidneys of mice with UUO and TGF-β1-stimulated HK-2 cells, accompanied by the up-regulation of long-chain acyl-CoA synthetase 1 (ACSL1). lncRNA H19 was identified as a sponge of microRNA-130a-3p, through which lncRNA H19 modulates the expression of ACSL1. The overexpression of microRNA-130a-3p reversed the lncRNA H19-induced increases in the expression of ACSL1. The suppressive effects of lncRNA H19 overexpression on the EMT, inflammation and lipid accumulation in HK-2 cells were diminished by ACSL1 silencing or microRNA-130a-3p overexpression. Overall, the findings showed that lncRNA H19 ameliorated renal tubulointerstitial fibrosis by reducing lipid deposition via modulation of the microRNA-130a-3p/ACSL1 axis.

Uncovering the functions and mechanisms of regulatory elements-associated non-coding RNAs

Over the past decade, regulatory non-coding RNAs (ncRNAs) produced by RNA Pol II have been revealed as meaningful players in various essential cellular functions. In particular, thousands of ncRNAs are produced at transcriptional regulatory elements such as enhancers and promoters, where they may exert multiple functions to regulate proper development, cellular programming, transcription or genomic stability. Here, we review the mechanisms involving these regulatory element-associated ncRNAs, and particularly enhancer RNAs (eRNAs) and PROMoter uPstream Transcripts (PROMPTs). We contextualize the mechanisms described to the processing and degradation of these short lived RNAs. We summarize recent findings explaining how ncRNAs operate locally at promoters and enhancers, or further away, either shortly after their production by RNA Pol II, or through post-transcriptional stabilization. Such discoveries lead to a converging model accounting for how ncRNAs influence cellular fate, by acting on transcription and chromatin structure, which may further involve factors participating to 3D nuclear organization.

New sights on long non-coding RNAs in glioblastoma: A review of molecular mechanism

Glioma or glioblastoma (GBM) is one of the aggressive and fatal primary cerebral malignancies, with the highest mortality rate among all brain-related tumors. Also, glioma mainly progresses as a more invasive phenotype after primary treatment. Cumulative evidence suggested that dysregulation of noncoding RNAs (ncRNAs) such as long non-coding RNAs (LncRNAs) and microRNAs (miRNAs) are associated with tumor initiation, progression, and drug resistance, through epigenetic modifications, transcriptional, and post-transcriptional processes in the cells. Many scientific investigations have revealed that LncRNAs play important roles in various biological procedures linked with the development and progression of GBM. In recent years, it has been shown that dysregulation of molecular mechanisms in many LncRNAs such as MIR22HG, HULC, AGAP2-AS1, MALAT1, PVT1, TTTY14, HOTAIRM1, PTAR, LPP-AS2, LINC00336, and TINCR are connected with the GBM. Therefore, this scientific review paper focused on the molecular mechanisms of these LncRNAs in the context of GBM.

LncRNAs modulating tooth development and alveolar resorption: Systematic review

Tooth development is an intricate process that encompasses cellular activities, molecular signaling pathways, and gene expression patterns. Disruptions in any of the processes can lead to structural anomalies, impairments in function, and increased vulnerability to oral disorders. Alveolar resorption, which refers to the pathological loss of alveolar bone around teeth, poses a substantial clinical problem in periodontal disorders such as periodontitis. Long non-coding RNAs (LncRNAs) have been implicated in the regulation of these physiological and pathological processes, and they exert their impact on gene expression through both transcriptional and post-transcriptional mechanisms. However, they also interact with certain microRNAs (mi-RNAs), thereby modulating the expression of downstream genes that are involved in tooth development. An exemplar is lncRNA ZFAS1, which has been demonstrated to regulate gene expression and impact these physiological and pathological processes. As a result, lncRNAs contribute to these processes by interacting with chromatin regulators, RNA enhancers, mi-RNAs, and their modulating signaling pathways involved in tooth development and alveolar resorption. Taken together, this review explores and gives a systematic account of the recent research findings that enhance our understanding of the molecular mechanisms that drive these processes and their potential consequences for the remodeling of teeth and bones in the oral cavity.

Epigenetic regulation of cGAS and STING expression in cancer

Although cancer immunotherapy has become a successful therapeutic strategy in a certain range of solid cancer and hematological malignancies, this efficacy of immunotherapy is impeded by limited success rates due to an immunologically "cold" state. The cGAS-STING signaling pathway is an evolutionarily conserved system which can find cytoplasmic DNA to regulate the innate immune and adaptive immune response. Beyond the host defense and autoimmune disorders, recent advances have now expanded the roles of cGAS-STING that is precise activated and tight regulated to improve anticancer immunity. Mounting evidence now has shown the crucial role of epigenetic regulation in mediating the expression of key genes associated with the cGAS-STING signaling pathway. In this review, we highlight the structure and cellular localization of cGAS and STING as well as intracellular cascade reaction of cGAS-STING signal transduction. We further summarize recent findings of epigenetic regulatory mechanisms that control the expression of cGAS and STING in cancer. The review aims to offer theoretical basis and reference for targeting the epigenetic mechanisms that control cGAS and STING gene expression to promote the development of more effective combination therapeutic regimens to enhance the efficacy of cancer immunotherapy in clinical practice and cancer clinical and cancer research workers.

A long noncoding RNA at the cortex locus controls adaptive coloration in butterflies

Evolutionary variation in the wing pigmentation of butterflies and moths offers striking examples of adaptation by crypsis and mimicry. The cortex locus has been independently mapped as the locus controlling color polymorphisms in 15 lepidopteran species, suggesting that it acts as a genomic hotspot for the diversification of wing patterns, but functional validation through protein-coding knockouts has proven difficult to obtain. Our study unveils the role of a long noncoding RNA (lncRNA) which we name ivory, transcribed from the cortex locus, in modulating color patterning in butterflies. Strikingly, ivory expression prefigures most melanic patterns during pupal development, suggesting an early developmental role in specifying scale identity. To test this, we generated CRISPR mosaic knock-outs in five nymphalid butterfly species and show that ivory mutagenesis yields transformations of dark pigmented scales into white or light-colored scales. Genotyping of Vanessa cardui germline mutants associates these phenotypes to small on-target deletions at the conserved first exon of ivory. In contrast, cortex germline mutant butterflies with confirmed null alleles lack any wing phenotype and exclude a color patterning role for this adjacent gene. Overall, these results show that a lncRNA gene acts as a master switch of color pattern specification and played key roles in the adaptive diversification of wing patterns in butterflies.

PRDM16-DT is a novel lncRNA that regulates astrocyte function in Alzheimer's disease

Astrocytes provide crucial support for neurons, contributing to synaptogenesis, synaptic maintenance, and neurotransmitter recycling. Under pathological conditions, deregulation of astrocytes contributes to neurodegenerative diseases such as Alzheimer's disease (AD). While most research in this field has focused on protein-coding genes, non-coding RNAs, particularly long non-coding RNAs (lncRNAs), have emerged as significant regulatory molecules. In this study, we identified the lncRNA PRDM16-DT as highly enriched in the human brain, where it is almost exclusively expressed in astrocytes. PRDM16-DT and its murine homolog, Prdm16os, are downregulated in the brains of AD patients and in AD models. In line with this, knockdown of PRDM16-DT and Prdm16os revealed its critical role in maintaining astrocyte homeostasis and supporting neuronal function by regulating genes essential for glutamate uptake, lactate release, and neuronal spine density through interactions with the RE1-Silencing Transcription factor (Rest) and Polycomb Repressive Complex 2 (PRC2). Notably, CRISPR-mediated overexpression of Prdm16os mitigated functional deficits in astrocytes induced by stimuli linked to AD pathogenesis. These findings underscore the importance of PRDM16-DT in astrocyte function and its potential as a novel therapeutic target for neurodegenerative disorders characterized by astrocyte dysfunction.

ST8SIA6-AS1, a novel lncRNA star in liver cancer

Liver cancer is one of the most lethal gastrointestinal malignancies. Emerging evidence has underscored the pivotal role of long non-coding RNAs (lncRNAs) in tumorigenesis, with ST8SIA6-AS1 identified as a novel oncogenic lncRNA contributing to liver cancer progression. ST8SIA6-AS1 is consistently upregulated in hepatic cancer tissues and is strongly associated with unfavorable prognosis. Moreover, it demonstrates high diagnostic efficacy in detecting HCC. ST8SIA6-AS1 is involved in various cellular processes including proliferation, migration, and invasion, primarily through its function as a competing endogenous RNA (ceRNA), thereby facilitating hepatocarcinogenesis and disease advancement. This review provides a detailed examination of the molecular functions and regulatory mechanisms of ST8SIA6-AS1 in hepatocellular carcinoma (HCC) and highlights its potential as a promising biomarker for liver cancer, aiming to propel the development of innovative therapeutic strategies for HCC management.

Spinal Cord Injury: From MicroRNAs to Exosomal MicroRNAs

Spinal cord injury (SCI) is an unfortunate experience that may generate extensive sensory and motor disabilities due to the destruction and passing of nerve cells. MicroRNAs are small RNA molecules that do not code for proteins but instead serve to regulate protein synthesis by targeting messenger RNA's expression. After SCI, secondary damage like apoptosis, oxidative stress, inflammation, and autophagy occurs, and differentially expressed microRNAs show a function in these procedures. Almost all animal and plant cells release exosomes, which are sophisticated formations of lipid membranes. These exosomes have the capacity to deliver significant materials, such as proteins, RNAs and lipids, to cells in need, regulating their functions and serving as a way of communication. This new method offers a fresh approach to treating spinal cord injury. Obviously, the exosome has the benefit of conveying the transported material across performing regulatory activities and the blood-brain barrier. Among the exosome cargoes, microRNAs, which modulate their mRNA targets, show considerable promise in the pathogenic diagnosis, process, and therapy of SCI. Herein, we describe the roles of microRNAs in SCI. Furthermore, we emphasize the importance of exosomal microRNAs in this disease.

Epigenetics of cerebrovascular diseases: an update review of clinical studies

Cerebrovascular diseases, especially stroke, are critical and heterogenous clinical conditions associated with high mortality and chronic disability. Genome-wide association studies reveal substantial stroke heritability, though specific genetic variants account for a minor fraction of stroke risk, suggesting an essential role for the epigenome. Epigenome-wide association studies and candidate gene approaches show that DNA methylation patterns significantly influence stroke susceptibility. Additionally, chromatin remodelers and non-coding RNA regulate gene expression in response to ischemic conditions. In this updated review, we summarized the progress of knowledge on epigenetics in the field of ischemic stroke underlying opportunities and challenges.

Sperm epigenetics and male infertility: unraveling the molecular puzzle

BACKGROUND

The prevalence of infertility among couples is estimated to range from 8 to 12%. A paradigm shift has occurred in understanding of infertility, challenging the notion that it predominantly affects women. It is now acknowledged that a significant proportion, if not the majority, of infertility cases can be attributed to male-related factors. Various elements contribute to male reproductive impairments, including aberrant sperm production caused by pituitary malfunction, testicular malignancies, aplastic germ cells, varicocele, and environmental factors.

MAIN BODY

The epigenetic profile of mammalian sperm is distinctive and specialized. Various epigenetic factors regulate genes across different levels in sperm, thereby affecting its function. Changes in sperm epigenetics, potentially influenced by factors such as environmental exposures, could contribute to the development of male infertility.

CONCLUSION

In conclusion, this review investigates the latest studies pertaining to the mechanisms of epigenetic changes that occur in sperm cells and their association with male reproductive issues.

KMT2C and KMT2D aberrations in breast cancer

KMT2C and KMT2D are histone lysine methyltransferases responsible for the monomethylation of histone 3 lysine 4 (H3K4) residues at gene enhancer sites. KMT2C/D are the most frequently mutated histone methyltransferases (HMTs) in breast cancer, occurring at frequencies of 10-20% collectively. Frequent damaging and truncating somatic mutations indicate a tumour-suppressive role of KMT2C/D in breast oncogenesis. Recent studies using cell lines and mouse models to replicate KMT2C/D loss show that these genes contribute to oestrogen receptor (ER)-driven transcription in ER+ breast cancers through the priming of gene enhancer regions. This review provides an overview of the functions of KMT2C/D and outlines the recent clinical and experimental evidence of the roles of KMT2C and KMT2D in breast cancer development.

Long noncoding RNA expression in acute lymphoblastic leukemia: A systematic review

Long noncoding RNAs (lncRNAs), as gene expression modulators, are potential players in Acute Lymphoblastic Leukemia (ALL) pathogenesis. We systematically explored current literature on lncRNA expression in ALL to identify lncRNAs consistently reported as differentially expressed (DE) either in ALL versus controls or between ALL subtypes. By comparing articles that provided global expression data for DE lncRNAs in the ETV6::RUNX1-positive ALL subtype, we identified four DE lncRNAs in three independent studies (two versus other subtypes and one versus controls), showing concordant expression of LINC01013, CRNDE and lnc-KLF7-1. Additionally, LINC01503 was consistently downregulated on ALL versus controls. Within RT-qPCR studies, twelve lncRNA were DE in more than one source. Thus, several lncRNAs were supported as DE in ALL by multiple sources, highlighting their potential role as candidate biomarkers or therapeutic targets. Finally, as lncRNA annotation is rapidly expanding, standardization of reporting and nomenclature is urgently needed to improve data verifiability and compilation.

Comprehensive analysis identifies long non-coding RNA RNASEH1-AS1 as a potential prognostic biomarker and oncogenic target in hepatocellular carcinoma

RNASEH1-AS1, a long non-coding RNA (lncRNA) divergently transcribed from the antisense strand of its neighboring protein-coding gene ribonuclease H1 (RNASEH1), has recently been demonstrated to be involved in tumor progression. However, the association between RNASEH1-AS1 and hepatocellular carcinoma (HCC) remains unclear. In the present study, first, the expression of RNASEH1-AS1 in HCC and its correlation with clinicopathological features, prognosis, diagnosis, immune cell infiltration of HCC patients was inspected using relevant R packages based on The Cancer Genome Atlas (TCGA) data. RNASEH1-AS1 was found to be up-regulated in most cancer types, including HCC, and its overexpression was significantly associated with histologic grade and AFP level as well as poor prognosis, and was an independent risk factor affecting overall survival with good diagnostic and prognostic values for HCC. RNASEH1-AS1 was inversely associated with the infiltration of most immune cell types, including plasmacytoid dendritic cells (pDC), B cells and neutrophils. Second, a total of 1109 positively co-expressed genes (PCEGs) of RNASEH1-AS1 were screened out in HCC by correlation analysis in batches (|Spearman's r| >0.4 and adjusted P value <0.01). GO and KEGG enrichment analysis indicated that PCEGs of RNASEH1-AS1 were mainly related to RNA processing, ribosome biogenesis, transcription and histone acetylation. The top 10 hub genes (EIF4A3, WDR43, WDR12, DKC1, NAT10, UTP18, DDX18, BYSL, DDX10, PDCD11) were identified by constructing the protein-protein interaction (PPI) network, and they were all highly expressed in HCC and positively correlated with histological grade. Third, a risk model was constructed based on four RNASEH1-AS1-related hub genes (EIF4A3, WDR12, DKC1, and NAT10) with good prognostic predictive potential via univariate Cox and the least absolute selection operator (LASSO) regression analysis. Fourth, experimental validation revealed that RNASEH1-AS1 was significantly elevated in HCC tissues and several cell lines, and its knockdown could suppress the proliferation, migration, and invasion of HCC cells. Finally, mechanistic studies demonstrated that the stability of RNASEH1-AS1 could be regulated by DKC1 via their direct interaction. Taken together, RNASEH1-AS1 may serve as a potential prognostic and diagnostic biomarker and oncogenic lncRNA for HCC.

Garlic-derived compounds: Epigenetic modulators and their antitumor effects

Cancer is a highly heterogeneous disease that poses a serious threat to human health worldwide. Despite significant advances in the diagnosis and treatment of cancer, the prognosis and survival rate of cancer remain poor due to late diagnosis, drug resistance, and adverse reactions. Therefore, it is very necessary to study the development mechanism of cancer and formulate effective therapeutic interventions. As widely available bioactive substances, natural products have shown obvious anticancer potential, especially by targeting abnormal epigenetic changes. The main active part of garlic is organic sulfur compounds, of which diallyl trisulfide (DATS) content is the highest, accounting for more than 40% of the total composition. The garlic-derived compounds have been recognized as an antioxidant for cancer prevention and treatment. However, the molecular mechanism of the antitumor effect of garlic-derived compounds remains unclear. Recent studies have identified garlic-derived compound DATS that plays critical roles in enhancing CpG demethylation or promoting histone acetylation as an epigenetic inhibitor. Here, we review the therapeutic progress of garlic-derived compounds against cancer through epigenetic pathways.

smFISH for Plants

Single-molecule fluorescence in situ hybridization (smFISH) is a powerful method for the visualization and quantification of individual RNA molecules within intact cells. With its ability to probe gene expression at the single cell and single-molecule level, the technique offers valuable insights into cellular processes and cell-to-cell heterogeneity. Although widely used in the animal field, its use in plants has been limited. Here, we present an experimental smFISH workflow that allows researchers to overcome hybridization and imaging challenges in plants, including sample preparation, probe hybridization, and signal detection. Overall, this protocol holds great promise for unraveling the intricacies of gene expression regulation and RNA dynamics at the single-molecule level in whole plants.

ELOVL2-AS1 suppresses tamoxifen resistance by sponging miR-1233-3p in breast cancer

Tamoxifen (Tam) has long been a top treatment option for breast cancer patients, but the challenge of eliminating cancer recurrence remains. Here, we identify a signalling pathway involving ELOVL2, ELOVL2-AS1, and miR-1233-3p, which contributes to drug resistance in Tam-resistant (TamR) breast cancer. ELOVL2-AS1, a long noncoding RNA, was significantly upregulated by its antisense gene, ELOVL2, which is known to be downregulated in TamR cells. Additionally, ELOVL2-AS1 underwent the most hypermethylation in MCF-7/TamR cells. Furthermore, patients with breast cancer who developed TamR during chemotherapy had significantly lower expression of ELOVL2-AS1 compared to those who responded to Tam. Ectopic downregulation of ELOVL2-AS1 by siRNA both stimulated cancer cell growth and deteriorated TamR. We also found that ELOVL2-AS1 sponges miR-1233-3p, which has pro-proliferative activity and elevates TamR, leading to the activation of potential target genes, such as MYEF2, NDST1, and PIK3R1. These findings suggest that ELOVL2-AS1, in association with ELOVL2, may contribute to the suppression of drug resistance by sponging miR-1233-3p in breast cancer.

Mutant FUS induces chromatin reorganization in the hippocampus and alters memory processes

Cytoplasmic mislocalization of the nuclear Fused in Sarcoma (FUS) protein is associated to amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Cytoplasmic FUS accumulation is recapitulated in the frontal cortex and spinal cord of heterozygous Fus∆NLS/+ mice. Yet, the mechanisms linking FUS mislocalization to hippocampal function and memory formation are still not characterized. Herein, we show that in these mice, the hippocampus paradoxically displays nuclear FUS accumulation. Multi-omic analyses showed that FUS binds to a set of genes characterized by the presence of an ETS/ELK-binding motifs, and involved in RNA metabolism, transcription, ribosome/mitochondria and chromatin organization. Importantly, hippocampal nuclei showed a decompaction of the neuronal chromatin at highly expressed genes and an inappropriate transcriptomic response was observed after spatial training of Fus∆NLS/+ mice. Furthermore, these mice lacked precision in a hippocampal-dependent spatial memory task and displayed decreased dendritic spine density. These studies shows that mutated FUS affects epigenetic regulation of the chromatin landscape in hippocampal neurons, which could participate in FTD/ALS pathogenic events. These data call for further investigation in the neurological phenotype of FUS-related diseases and open therapeutic strategies towards epigenetic drugs.

Epigenetic associations with adolescent grey matter maturation and cognitive development

Introduction: Adolescence, a critical phase of human neurodevelopment, is marked by a tremendous reorganization of the brain and accompanied by improved cognitive performance. This development is driven in part by gene expression, which in turn is partly regulated by DNA methylation (DNAm). Methods: We collected brain imaging, cognitive assessments, and DNAm in a longitudinal cohort of approximately 200 typically developing participants, aged 9-14. This data, from three time points roughly 1 year apart, was used to explore the relationships between seven cytosine-phosphate-guanine (CpG) sites in genes highly expressed in brain tissues (GRIN2D, GABRB3, KCNC1, SLC12A9, CHD5, STXBP5, and NFASC), seven networks of grey matter (GM) volume change, and scores from seven cognitive tests. Results: The demethylation of the CpGs as well as the rates of change in DNAm were significantly related to improvements in total, crystalized, and fluid cognition scores, executive function, episodic memory, and processing speed, as well as several networks of GM volume increases and decreases that highlight typical patterns of brain maturation. Discussion: Our study provides a first look at the DNAm of genes involved in myelination, excitatory and inhibitory receptors, and connectivity, how they are related to the large-scale changes occurring in the brain structure as well as cognition during adolescence.