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Differential gene expression profiling in genetic and multifactorial cardiovascular diseases.

Gene expression profiling by microarray technologies has been successfully applied to study the transcriptional changes that occur in tissues such as heart, vessels and blood cells in different cardiovascular disorders. Such studies have been performed in human cardiovascular syndromes and in animal models with the aim of unraveling the complex molecular pictures underlying human pathophysiology. As already observed in cancer research, gene expression studies in humans may provide a finer molecular classification of patients with cardiovascular diseases and indicate new markers useful for prognostic and therapeutic strategies. In this paper, we present the findings obtained with microarray platforms to explore transcriptome alterations in cardiovascular diseases. To describe the potential of global expression profiling approach in this field, we have chosen to review the genomic findings obtained in some classic heart diseases with genetic transmission such as hyperthrophic cardiomyopathy and Fabry disease, together with findings obtained in common multifactorial cardiovascular disorders such as heart failure, atherosclerosis and infarction. Wherever feasible, we present the results obtained in patients together with those obtained in the corresponding animal and cellular models.

Animals↗

Comparative transcriptome analysis of Qinchuan and Wagyu cattle reveals lnc11599 as a negative regulator of intramuscular fat deposition.

BACKGROUND: Intramuscular fat (IMF) content is a critical factor determining beef quality, influenced by various factors including breed and age. However, the regulatory role of long non-coding RNAs (lncRNAs) in IMF deposition remains unclear. METHODS: This study investigated IMF deposition in the longissimus dorsi muscle of one- and two-year-old Qinchuan and Wagyu cattle through histological examination and fat content measurement. Based on transcriptome sequencing data of intramuscular fat tissue, differential expression analysis and weighted gene co-expression network analysis (WGCNA) were performed to identify lncRNAs associated with IMF deposition. The effects of a key candidate lncRNA on the adipogenic differentiation of cattle intramuscular preadipocytes were further examined. RESULTS: Results showed that Wagyu cattle exhibited stronger IMF deposition capacity than Qinchuan cattle across all age groups, with IMF content increasing with age in both breeds. We identified 7,910 lncRNAs from intramuscular fat tissue transcriptome data, including 6,455 novel lncRNAs. Through integrated differential expression analysis and WGCNA, 88 lncRNAs closely associated with IMF deposition were screened from two-year-old Qinchuan and Wagyu cattle. Notably, lnc11599 was significantly upregulated in Qinchuan cattle intramuscular fat tissue, but its expression decreased during intramuscular preadipocyte differentiation. Functional experiments demonstrated that lnc11599 knockdown enhanced adipogenic differentiation capacity, manifested as a highly significant increase in lipid accumulation, upregulation of key adipogenic genes at the mRNA level, together with increases in total fatty acid content and unsaturated fatty acid proportion. CONCLUSIONS: This study established the lncRNA expression profiles in intramuscular fat tissue of Qinchuan and Wagyu cattle across different developmental stages, and demonstrated that lnc11599 acts as a negative regulator of intramuscular fat deposition. These findings provide new directions for elucidating the mechanisms of cattle IMF deposition and offer potential targets for genetic improvement of beef quality.

Animals↗

Gene expression profiling of the tetrapyrrole metabolic pathway in Arabidopsis with a mini-array system.

Tetrapyrrole compounds, such as chlorophylls, hemes, and phycobilins, are synthesized in many enzymatic steps. For regulation of the tetrapyrrole metabolic pathway, it is generally considered that several specific isoforms catalyzing particular enzymatic steps control the flow of tetrapyrrole intermediates by differential regulation of gene expression depending on environmental and developmental factors. However, the coordination of such regulatory steps and orchestration of the overall tetrapyrrole metabolic pathway are still poorly understood. In this study, we developed an original mini-array system, which enables the expression profiling of each gene involved in tetrapyrrole biosynthesis simultaneously with high sensitivity. With this system, we performed a transcriptome analysis of Arabidopsis seedlings in terms of the onset of greening, endogenous rhythm, and developmental control. Data presented here clearly showed that based on their expression profiles at the onset of greening, genes involved in tetrapyrrole biosynthesis can be classified into four categories, in which genes are coordinately regulated to control the biosynthesis. Moreover, genes in the same group were similarly controlled in an endogenous rhythmic manner but also by a developmental program. The physiological significance of these gene clusters is discussed.

Arabidopsis↗

Epigenetics and In Silico Transcriptome Analysis of Pediatric Acute Myeloid Leukemia.

Pediatric acute myeloid leukemia (AML) is a heterogeneous hematologic malignancy that accounts for about 15%-20% of childhood leukemias. Despite therapeutic advances, relapses remain common, and survival for high-risk patients is below 60%. Unlike adult AML, pediatric AML displays distinct genetic mutations, including FLT3-ITD, NPM1, KMT2A rearrangements, and core-binding factors (CBF) fusions, as well as extensive epigenetic dysregulation. Aberrant DNA methylation, histone modifications, and altered non-coding RNA expressions disrupt hematopoietic differentiation and activate oncogenic transcriptional networks. Recent advances in silico transcriptomic analysis have transformed the study of pediatric AML by integrating gene expression and epigenetic data to identify molecular drivers and regulatory networks. Computational RNA-seq pipelines and pathway analyses have highlighted key epigenetic regulators, including DNMT3A, TET2, and HDACs, as potential therapeutic targets. Multi-omics approaches combining transcriptomic, methylomic, and chromatin accessibility data are increasingly used to define biomarkers for diagnosis, prognosis, and therapeutic response. This review provides a comprehensive overview of the molecular and epigenetic landscape of pediatric AML, emphasizing the power of in silico transcriptome analysis to uncover disease mechanisms, refine patient stratification, and guide the development of precision-based epigenetic therapies aimed at improving long-term outcomes in children with AML.

Humans↗

De novo transcriptome meta-analysis reveals candidate genes involved in life-stage transitions for RNAi-mediated management of the citrus root weevil (Diaprepes abbreviatus).

BACKGROUND: The citrus root weevil, Diaprepes abbreviatus, is a destructive agricultural pest for which molecular control options remain limited due to historically sparse genomic resources. Leveraging a comprehensive de novo transcriptome, we investigated developmental gene regulation across larval, pupal, and adult stages and identified essential targets for RNA interference (RNAi)-based intervention. RESULTS: Stage-resolved transcriptomic analyses revealed extensive transcriptional reprogramming associated with metabolism, detoxification, cuticle biosynthesis, endocrine signaling, and sensory perception. Among these, chitin synthase (DaCHS) emerged as a critical developmental gene, exhibiting pronounced up-regulation during late larval and pupal stages corresponding to intensive cuticle synthesis. Phylogenetic and structural analyses demonstrated that DaCHS is highly conserved among insects and retains canonical catalytic domains and transmembrane topology. Alpha Fold-based structural modeling and molecular docking confirmed stable interaction of DaCHS with its substrate, N-acetylglucosamine, supporting functional conservation of enzymatic activity. Oral delivery of DaCHS double-stranded RNA induced robust transcript suppression, leading to significant mortality and severe developmental defects, including larval and pupal abnormalities, and adults with disrupted wing and abdominal morphogenesis. CONCLUSION: These findings establish DaCHS as an indispensable gene for D. abbreviates development and validate transcriptome-guided RNAi as a powerful framework for target discovery. This work provides a strong molecular foundation for developing RNAi-based strategies that can be integrated into sustainable management programs for citrus root weevil control. © 2026 Society of Chemical Industry.

Animals↗

Transcriptomic and RNAi analyses reveal chloride channel 3-associated osmoregulation in Litopenaeus vannamei under low-salinity stress.

Chloride channels and transporters are important for cellular volume regulation and salinity adaptation in euryhaline crustaceans, yet the intestinal transcriptional relationship between plasma-membrane and intracellular chloride pathways remains unclear in Litopenaeus vannamei. In this study, RNA interference of anoctamin 1 (ANO1) was combined with intestinal transcriptome sequencing under the production-relevant low-salinity condition of salinity 3. ANO1 silencing produced a focused transcriptional response, with 16 differentially expressed genes (DEGs) identified (11 upregulated and 5 downregulated). Functional enrichment indicated that these genes were associated with transporter activity, cytoskeletal organization, extracellular matrix-receptor interaction, membrane lipid metabolism, and vesicular processes. Notably, a transcript encoding chloride channel protein 3 (CLC-3) was significantly upregulated following ANO1 knockdown, suggesting a potential transcriptional relationship between ANO1 and CLC-3 in chloride homeostasis. Based on this finding, CLC-3 was selected for full-length cDNA cloning, sequence characterization, salinity-gradient expression analysis, and RNAi-based functional assessment. The cloned CLC-3 cDNA was 2883 bp in length and encoded an 850 amino acid protein containing a conserved voltage-gated chloride channel (Voltage-CLC) domain and two cystathionine β-synthase domains. Phylogenetic analysis placed LvCLC-3 within the intracellular CLC-c clade, and tissue distribution analysis showed the highest CLC-3 expression in the intestine. Intestinal CLC-3 expression responded nonlinearly to salinity variation, peaking at salinity 20. Under salinity 3, CLC-3 knockdown reduced ANO1, Na+/K+-ATPase alpha subunit, and Na+-K+-2Cl- cotransporter transcript levels, whereas glutamate-gated chloride channel expression increased. Mild hepatopancreatic structural alterations were also observed after CLC-3 knockdown. These findings suggest that CLC-3 is a salinity-responsive intracellular chloride-transporter candidate associated with intestinal ion-transport-related transcriptional responses after ANO1 suppression in L. vannamei, although the underlying physiological mechanism requires further validation.

Animals↗

scGPA: an LLM-assisted workflow for directional virtual gene perturbation analysis from single-cell transcriptomes.

BACKGROUND: Existing virtual perturbation methods can often infer directional changes by comparing predicted post-perturbation expression profiles with control cells. However, workflows that directly return direction-specific downstream candidate genes together with confidence scores, evidence support and interpretable summaries remain limited. We developed scGPA, an LLM-assisted workflow system for directional single-cell virtual gene perturbation analysis. METHODS: scGPA starts from raw single-cell RNA sequencing data and performs quality control, normalization, dimensionality reduction, clustering and cell-group selection. It then constructs cell-group-specific wild-type regulatory networks using repeated subsampling, principal component regression (PCR)/Ridge-based network inference and CP tensor denoising. Based on these networks, scGPA simulates dose-aware virtual knockdown of the target gene and applies signed perturbation propagation to estimate the magnitude and direction of downstream transcriptional responses. LLM assistance is used for marker-based cell-type annotation, evidence-guided candidate prioritization and user-facing biological summarization. RESULTS: We benchmarked scGPA across five public Perturb-seq datasets and compared its performance with GEARS, scGPT and a random baseline. The overall correct prediction rate of scGPA was 23.0%, exceeding those of GEARS (20.7%), scGPT (15.1%) and the random baseline (13.6%). These results indicate that scGPA achieved a higher correct prediction rate than the two comparator models and the random baseline. We subsequently evaluated scGPA using a public osteosarcoma single-cell dataset and performed qRT-PCR validation in 143B osteosarcoma cells. Among genes with significant experimental changes, scGPA achieved a directional concordance of 76.9%. When all tested downstream genes were counted, 37.0% were directionally correct, 51.9% showed no significant change and 11.1% changed in the opposite direction. CONCLUSIONS: scGPA provides a practical workflow system for predicting and prioritizing direction-specific downstream transcriptional responses after target-gene perturbation. By integrating single-cell regulatory network inference, signed virtual perturbation and LLM-assisted interpretation, scGPA supports target-gene function inference and downstream mechanistic investigation from single-cell transcriptomic data.

Single-Cell Gene Expression Analysis↗

Drug repurposing using transcriptomics: principles and unmet needs in cardiovascular disease.

Although cardiovascular disease is the leading cause of death globally, therapeutic development in this field is slow. Given the high cost of developing new drugs and running clinical trials for cardiovascular disease, repurposing of drugs with approved safety profiles is an attractive strategy for therapeutic development that can significantly reduce the time and cost investment before phase II clinical trials. In the era of "Omics," various new methods and several large databases have been developed to enable the use of transcriptomics data for drug repurposing. This review summarizes the principles and workflow of signature mapping, which forms the foundation of statistical models used for transcriptome-based drug repurposing. We highlight the features of different analysis pipelines and databases that have been developed for signature mapping. These analysis pipelines prioritize genes that are statistically important, an approach that fundamentally differs from the pharmacological approach of identifying disease-driving and therapeutically targetable pathways. Outcomes of signature mapping pipelines are sensitive to the quality of input data, and results are not always reproducible. Moreover, all widely used RNA-seq databases are derived from cancer research and lack high-quality molecular data for cardiovascular disease. These unmet needs call for interdisciplinary collaboration and large networks of cardiovascular research-oriented biobanks to create the databases needed for transcriptomic-based signature mapping for drug repurposing efforts.

Drug Repositioning↗

Circadian oscillation of gene expression in murine calvarial bone.

UNLABELLED: The genes encoding the core circadian transcription factors display an oscillating expression profile in murine calvarial bone. More than 26% of the calvarial bone transcriptome exhibits a circadian rhythm, comparable with that observed in brown and white adipose tissues and liver. Thus, circadian mechanisms may directly modulate oxidative phosphorylation and multiple metabolic pathways in bone homeostasis. INTRODUCTION: Although circadian rhythms have been associated historically with central regulatory mechanisms, there is emerging evidence that the circadian transcriptional apparatus exists in peripheral tissues. The aim of this study was to determine the presence and extent of circadian oscillation in the transcriptome of murine calvarial bone. MATERIALS AND METHODS: Cohorts of 8-week-old male AKR/J mice were maintained in a controlled 12-h light:12-h dark cycle on an ad libitum diet for 2 weeks. Groups of three mice were killed every 4 h over a 48-h period. The level of gene expression at successive times-points was determined by quantitative RT-PCR and Affymetrix microarray. Data were analyzed using multiple statistical time series algorithms, including Cosinor, Fisher g-test, and the permutation time test. RESULTS: Both the positive (Bmal1, Npas2) and negative (Cry1, Cry2, Per1, Per2, Per3) elements of the circadian transcriptional apparatus and their immediate downstream targets and mediators (Dbp, Rev-erbalpha, Rev-erbbeta) exhibited oscillatory expression profiles. Consistent with findings in other tissues, the positive and negative elements were in antiphase relative to each other. More than 26% of the genes present on the microarray displayed an oscillatory profile in calvarial bone, comparable with the levels observed in brown and white adipose tissues and liver; however, only a subset of 174 oscillating genes were shared among all four tissues. CONCLUSIONS: Our findings show that the components of the circadian transcriptional apparatus are represented in calvarial bone and display coordinated oscillatory behavior. However, these are not the only genes to display an oscillatory expression profile, which is seen in multiple pathways involving oxidative phosphorylation and lipid, protein, and carbohydrate metabolism.

Adipose Tissue, Brown↗

Genome-wide analysis of mRNAs regulated by the THO complex in Drosophila melanogaster.

In yeast cells, the THO complex has been implicated in mitotic recombination, transcription elongation and mRNA nuclear export. The stable core of THO consists of Tho2p, Hpr1p, Mft1p and Thp2p. Whether a complex with similar functions assembles in metazoa has not yet been established. Here we report that Drosophila melanogaster THO consists of THO2, HPR1 and three proteins, THOC5-THOC7, which have no orthologs in budding yeast. Gene expression profiling in cells depleted of THO components revealed that <20% of the transcriptome was regulated by THO. Nonetheless, export of heat-shock mRNAs under heat stress was strictly dependent on THO function. Notably, 8% of upregulated genes encode proteins involved in DNA repair. Thus, although THO function seems to be conserved, the vast majority of mRNAs are transcribed and exported independently of THO in D. melanogaster.

Active Transport, Cell Nucleus↗

Laser-controlled microdissection of tissues opens a window of new opportunities.

Gene expression analysis using total RNA of bulk tissue usually cannot assign specific messages to particular cell types. Cell-specific RNA expression profiling, though, may be crucial for a better understanding ofthe role of each distinct cell type within a physiological or pathophysiological setting. RNA profiling based on laser-controlled microdissection (LCM) of defined cells of a tissue now provides a useful tool for studying molecular crosstalk between different cell types within a tissue. The LCM technique allows for efficient isolation of single cells with no or very low contamination of surrounding tissue components, simultaneously leaving the intracellular structure and molecules intact. In this review, different issues of the LCM technique and the RNA amplification procedure for microarray analysis are discussed. An exemplary summary of results obtained from gene profiling of epithelial and stromal cells from human prostate tumors is presented, demonstrating the power of LCM-based molecular analysis. Finally, we discuss the potential use of the LCM technique i) to study the transcriptome of distinct cells from formalin-fixed and paraffin-embedded tissues in subcellular RNA profiling and ii) high resolution proteomic and metabolistic studies.

Dissection↗

Action and reaction: Chlamydophila pneumoniae proteome alteration in a persistent infection induced by iron deficiency.

Chlamydophila pneumoniae is an obligate intracellular pathogen implicated in a variety of acute and chronic diseases. Long-term infections are associated with a persistent life stage, in which bacteria can stay for years. They are less accessible to antibiotic treatment but still prone to sustain an inflammatory response. Different in vitro models have been established to mimic and characterize chlamydial persistency. For C. pneumoniae and Chlamydia trachomatis, altered metabolic activities and changed antigenic profiles compared to acute infections have been reported. Most studies including transcriptome and proteome analyses describe persistency induced by IFNgamma treatment. Here, we use iron depletion of the infected cell culture that also leads into persistent infection. We describe differently regulated proteins found by subtractive proteome analysis comparing two early stages of infection with and without addition of the iron chelator deferoxamine-mesylate. While only one bacterial protein was up-regulated during iron deficiency up to 24 h post infection (p.i.), 11 were found to be up-regulated and eight to be down-regulated from 24-48 h p.i. Two down-regulated proteins could be identified by peptide mass fingerprinting as thioredoxin reductase and chromosome partitioning protein (ParB). The latter is involved in chromosome segregation. Thus, using a comparative approach we identified on a proteome level down-regulation of ParB in persistent chlamydial forms, which is in agreement with previous results describing changes in cell division and atypical altered morphology of persistent Chlamydiae.

Amino Acid Sequence↗

Study of Arabidopsis thaliana resistome in response to cucumber mosaic virus infection using whole genome microarray.

The plant innate immune response is mediated by resistance (R) genes and involves hypersensitive response (HR) cell death. During resistance responses, the host undergoes net changes in the transcriptome. To understand these changes, we generated a whole genome transcript profile for RCY1-mediated resistance to cucumber mosaic virus strain Y (CMV-Y) in Arabidopsis. Using a very stringent selection criterion, we identified 444 putative factors belonging to nine different functional classes that show significant transcript regulation during Arabidopsis-CMV-Y interaction. Genes with unknown function formed the largest class. Other functional classes represented in the resistome include kinases and phosphatases, protein degradation machinery/proteases, transcriptional regulators, and others. Interestingly, several of the unknown function genes possess well characterized domains and secondly many genes encode small peptides with less than 100 amino acids. Analysis of 1.1 kb promoter regions of the 444 genes revealed that 9 out of the 12 known cis-binding elements are significantly associated with pathogen responsive cluster. Location and distribution of five prominent binding elements for select group of disease resistance related and unknown function genes is presented. The analysis also revealed 80 defense-responsive genes that might participate in R gene-mediated defense against both viral and bacterial pathogens. In addition, chromosome distribution of genes that respond to bacterial and viral pathogens suggests that they are located in small gene clusters and may be transcriptionally co-regulated. Exploring the precise function of the new genes identified in this analysis will offer new insights into plant defense.

Analysis of Variance↗

Survey of current protein family databases and their application in comparative, structural and functional genomics.

The last two decades have witnessed significant expansions in the databases storing information on the sequences and structures of proteins. This has led to the creation of many excellent protein family resources, which classify proteins according to their evolutionary relationship. These have allowed extensive insights into evolution and particularly how protein function mutates and evolves over time. Such analyses have greatly assisted the inheritance of functional annotations between experimentally characterised and uncharacterised genes. Moreover, the development of bioinformatics tools acts as a companion to the new technologies emerging in biology, such as transcriptomics and proteomics. The latter enable researchers to analyse gene expression profiles and interactions on a genome-wide scale, generating vast datasets of proteins, many of which include experimentally uncharacterised proteins. Protein family/function databases can be used to help interpret this data and allow us to benefit more fully from these technologies. This review aims to summarise the most popular sequence- and structure-based protein family databases. We also cover their application to comparative genomics and the functional annotation of the genomes.

Biological Evolution↗

How can toxicogenomics inform risk assessment?

Technologies that generate information about the genome are being used to explore changes in gene expression and related proteins following exposure to chemicals. Conceptually, this information allows a greater understanding of genomic level mRNA expression (transcriptomics), cell and tissue protein expression (proteomics) and information about metabolite profiles (metabonomics). Having a greater understanding of this information alongside, empirical toxicological reference data provide for the continued evolution in our ability to understand toxicological modes of action, thereby providing a more scientific basis for extrapolation of toxicological information from animals to humans. Toxicogenomics also provides specific opportunities for improvements at different stages of the risk assessment process such as the development of new predictive models for identifying human health hazards and the identification of more precise molecular biomarkers of exposure. One possibility is that molecular fingerprinting in vivo or in vitro can be used to categorize chemicals and mixtures of chemicals into different mode of action groups. As there is indication that molecular signals differ at dose levels, it is hoped that toxicogenomic information can also contribute to the understanding and interpretation of effects seen with low dose exposure. Several gene polymorphisms have already been identified which play a role in the differing intra-species response to chemicals thus providing explanation for the observed differences in effects. It is therefore likely that a better understanding of genomic expression will enable a greater insight into the factors behind the observed variability in susceptibility to chemical exposure that can be seen in human populations.

Genomics↗

Phytotoxicity and innate immune responses induced by Nep1-like proteins.

We show that oomycete-derived Nep1 (for necrosis and ethylene-inducing peptide1)-like proteins (NLPs) trigger a comprehensive immune response in Arabidopsis thaliana, comprising posttranslational activation of mitogen-activated protein kinase activity, deposition of callose, production of nitric oxide, reactive oxygen intermediates, ethylene, and the phytoalexin camalexin, as well as cell death. Transcript profiling experiments revealed that NLPs trigger extensive reprogramming of the Arabidopsis transcriptome closely resembling that evoked by bacteria-derived flagellin. NLP-induced cell death is an active, light-dependent process requiring HSP90 but not caspase activity, salicylic acid, jasmonic acid, ethylene, or functional SGT1a/SGT1b. Studies on animal, yeast, moss, and plant cells revealed that sensitivity to NLPs is not a general characteristic of phospholipid bilayer systems but appears to be restricted to dicot plants. NLP-induced cell death does not require an intact plant cell wall, and ectopic expression of NLP in dicot plants resulted in cell death only when the protein was delivered to the apoplast. Our findings strongly suggest that NLP-induced necrosis requires interaction with a target site that is unique to the extracytoplasmic side of dicot plant plasma membranes. We propose that NLPs play dual roles in plant pathogen interactions as toxin-like virulence factors and as triggers of plant innate immune responses.

Arabidopsis↗

RNA Virus Diversity, Cross-Species Transmission, and Molecular Constraints in Two Closely Related Rat Species.

Viral infection involves co-evolution with hosts, yet the molecular determinants that constrain viral cross-species transmission remain poorly understood. Here, we established conspecific and heterospecific co-housing models for two closely related rat species, Rattus norvegicus (RN) and Rattus tanezumi (RT), both maintained in laboratory settings for over 10 generations, together with wild-caught RT individuals. Using meta-transcriptomic sequencing and population genomic analyses, we compared their RNA virus profiles and investigated the potential molecular constraints on cross-species viral transmission. From 63 rats, we characterized an extensive RNA virome comprising more than 600 viruses, including 7 zoonotic viruses, 29 viruses with cross-species transmission potential, and 335 novel viruses. Notably, the prevalence of Seoul orthohantavirus (SEOV) was significantly higher in RN than in RT. Population genomic analysis revealed that RN exhibited higher heterozygosity in Itgb3 (the gene encoding the SEOV receptor, &#x3b2;3-integrin) and Tlr7 (the gene encoding the receptor for viral ssRNA, Toll-like receptor 7) compared to RT. These genetic variations likely represent the molecular determinants responsible for the differential susceptibility to SEOV between the two species. Our findings clarify the diversity and prevalence of RNA viruses in closely related rodent species and highlight host genetic barriers that may influence zoonotic spillover risk.

Animals↗

Stochastic epigenetic mutation profiles as biomarkers of clinical activity in juvenile idiopathic arthritis: a multi-omic machine learning approach for gene prioritization.

BACKGROUND: Juvenile idiopathic arthritis (JIA) is a rare autoimmune disease arising from a complex interplay between genetic and environmental factors. Epigenetic modifications such as DNA methylation (DNAm) have been described as potential mediators in gene-environment interactions, contributing to immune system dysregulation. Emerging evidence suggests that DNAm profiles also predict therapeutic responses in autoimmune diseases. This study aims to identify epigenetic biomarkers and epigenetic-driven gene expression changes associated with JIA clinical activity. METHODS: We reanalyzed a publicly available dataset of 44 JIA patients, with whole-genome DNAm and gene expression from CD4&#x2009;+&#x2009;T cells measured at two points: at anti-TNF therapy withdrawal (T0) and eight months later (Tend). At Tend, 30 patients maintained inactive disease (ID) while 14 did not (NO ID). We investigated differences between ID and NO ID patients in the epigenetic mutation load and various epigenetic clocks through linear regression models, and prioritized genomic regions with significantly higher number of epimutations in NO ID patients through machine learning. RESULTS: We found a higher mutation load in NO ID than ID patients, both at T0 and at Tend, with the differences at Tend reaching statistical significance (p&#x2009;=&#x2009;0.02). In contrast, we found no evidence of association between epigenetic clocks and JIA clinical activity. Using a multi-omic approach, we identified a List of candidate epigenetically-driven differentially expressed genes, 80 up-regulated and 77 down-regulated, in NO ID patients. Finally, comparing our candidate gene list with the Connectivity Map database, we identified new candidate potential therapeutic targets. Key findings were validated in independent datasets: DNAm profiles from CD4&#x2009;+&#x2009;T cells (56 JIA patients, 57 controls) and transcriptomic data from PBMCs of JIA patients with active or inactive disease, confirming dysregulation of pathways such as TNF-&#x3b1; signaling via NF-kB and TGF-&#x3b2; signaling among others. CONCLUSIONS: We described a significant association of epigenetic mutations with JIA clinical activity, indicating that epigenetic changes might precede clinical symptoms and may serve as biomarkers for early disease monitoring. Further, our results shed light on biomolecular mechanisms of JIA, supporting the development of more effective treatments.

Humans↗