Gene Expression Patterns Research Articles

Identification of PANoptosis-related subtypes, construction of a prognosis signature, and tumor microenvironment landscape of hepatocellular carcinoma using bioinformatic analysis and experimental verification.

Hepatocellular carcinoma (HCC) is one of the most lethal malignancies worldwide. PANoptosis is a recently unveiled programmed cell death pathway, Nonetheless, the precise implications of PANoptosis within the context of HCC remain incompletely elucidated. We conducted a comprehensive bioinformatics analysis to evaluate both the expression and mutation patterns of PANoptosis-related genes (PRGs). We categorized HCC into two clusters and identified differentially expressed PANoptosis-related genes (DEPRGs). Next, a PANoptosis risk model was constructed using LASSO and multivariate Cox regression analyses. The relationship between PRGs, risk genes, the risk model, and the immune microenvironment was studies. In addition, drug sensitivity between high- and low-risk groups was examined. The expression profiles of these four risk genes were elucidate by qRT-PCR or immunohistochemical (IHC). Furthermore, the effect of CTSC knock down on HCC cell behavior was verified using in vitro experiments. We constructed a prognostic signature of four DEPRGs (CTSC, CDCA8, G6PD, and CXCL9). Receiver operating characteristic curve analyses underscored the superior prognostic capacity of this signature in assessing the outcomes of HCC patients. Subsequently, patients were stratified based on their risk scores, which revealed that the low-risk group had better prognosis than those in the high-risk group. High-risk group displayed a lower Stromal Score, Immune Score, ESTIMATE score, and higher cancer stem cell content, tumor mutation burden (TMB) values. Furthermore, a correlation was noted between the risk model and the sensitivity to 56 chemotherapeutic agents, as well as immunotherapy efficacy, in patient with. These findings provide valuable guidance for personalized clinical treatment strategies. The qRT-PCR analysis revealed that upregulated expression of CTSC, CDCA8, and G6PD, whereas downregulated expression of CXCL9 in HCC compared with adjacent tumor tissue and normal liver cell lines. The knockdown of CTSC significantly reduced both HCC cell proliferation and migration. Our study underscores the promise of PANoptosis-based molecular clustering and prognostic signatures in predicting patient survival and discerning the intricacies of the tumor microenvironment within the context of HCC. These insights hold the potential to advance our comprehension of the therapeutic contribution of PANoptosis plays in HCC and pave the way for generating more efficacious treatment strategies.

Transcriptomic insights into the dominance of two phototrophs throughout the water column of a tropical hypersaline-alkaline crater lake (Dziani Dzaha, Mayotte).

Saline-alkaline lakes often shelter high biomasses despite challenging conditions, owing to the occurrence of highly adapted phototrophs. Dziani Dzaha (Mayotte) is one such lake characterized by the stable co-dominance of the cyanobacterium Limnospira platensis and the picoeukaryote Picocystis salinarum throughout its water column. Despite light penetrating only into the uppermost meter, the prevailing co-dominance of these species persists even in light- and oxygen-deprived zones. Here, a depth profile of phototrophs metatranscriptomes, annotated using genomic data from isolated strains, is employed to identify expression patterns of genes related to carbon processing pathways including photosynthesis, transporters and fermentation. The findings indicate a prominence of gene expression associated with photosynthesis, with a peak of expression around 1 m below the surface, although the light intensity is very low and only red and dark red wavelengths can reach it, given the very high turbidity linked to the high biomass of L. platensis. Experiments on strains confirmed that both species do grow under these wavelengths, at rates comparable to those obtained under white light. A decrease in the expression of photosynthesis-related genes was observed in L. platensis with increasing depth, whereas P. salinarum maintained a very high pool of psbA transcripts down to the deepest point as a possible adaptation against photodamage, in the absence and/or very low levels of expression of genes involved in protection. In the aphotic/anoxic zone, expression of genes involved in fermentation pathways suggests active metabolism of reserve or available dissolved carbon compounds. Overall, L. platensis seems to be adapted to the uppermost water layer, where it is probably maintained thanks to gas vesicles, as evidenced by high expression of the gvpA gene. In contrast, P. salinarum occurs at similar densities throughout the water column, with a peak in abundance and gene expression levels which suggests a better adaptation to lower light intensities. These slight differences may contribute to limited inter-specific competition, favoring stable co-dominance of these two phototrophs.

Comparative Analysis of Maternal Gene Expression Patterns Unravels Evolutionary Signatures Across Reproductive Modes.

Maternal genes have a pivotal role in regulating metazoan early development. As such their functions have been extensively studied since the dawn of developmental biology. The temporal and spatial dynamics of their transcripts have been thoroughly described in model organisms and their functions have been undergoing heavy investigations. Yet, less is known about the evolutionary changes shaping their presence within diverse oocytes. Due to their unique maternal inheritance pattern, a high degree is predicted to be present when it comes to their expression. Insofar only limited and conflicting results have emerged around it. Here, we set out to elucidate which evolutionary changes could be detected in the maternal gene expression patterns using phylogenetic comparative methods on RNAseq data from 43 species. Using normalized gene expression values and fold change information throughout early development we set out to find the best-fitting evolutionary model. Through modeling, we find evidence supporting both the high degree of divergence and constraint on gene expression values, together with their temporal dynamics. Furthermore, we find that maternal gene expression alone can be used to explain the reproductive modes of different species. Together, these results suggest a highly dynamic evolutionary landscape of maternal gene expression. We also propose a possible functional dichotomy of maternal genes which is influenced by the reproductive strategy undertaken by examined species.

Validation of biomarkers and immunotherapy in head and neck squamous cell carcinoma using bioinformatics and Mendelian randomization

Background To promote carcinogenesis through diverse molecular pathways involving dysregulation of gene expression and abnormalities. Methods We employed Mendelian randomization (MR) to uncover causal relationships between genetic factors and HNSCC. We used the Inverse Variance Weighted (IVW) method as the primary MR analysis, and validated the results through complementary approaches like MR-Egger regression, weighted median, and mode analyses. Results Our analysis identified 2210 genes that are differentially expressed in head and neck cancer (HNSCC) compared to normal tissues. Within the protein interaction network, the genes IL1B, CXCL8, CXCL1, and CCL2 stood out as central hubs. Further investigation revealed that these key genes are involved in important biological processes like skin development, wound healing, and fat metabolism. Notably, our Mendelian randomization analysis provided evidence for a causal relationship between the expression of the IL1B gene and the development of HNSCC. Conclusions Our analysis identified 5 key genes - IL1B, CXCL8, CXCL1, CCL2, and IL1B - that show significant changes in expression in head and neck cancer. These genes could serve as important new biomarkers to help diagnose this disease and track how it progresses over time. Importantly, these genes are involved in regulating the immune system, suggesting that the body’s immune response plays a critical role in head and neck cancer. This provides new avenues for future research to better understand the complex gene expression patterns underlying this type of cancer. Further investigation of these key genes and their regulatory networks could lead to important insights and potential new treatment approaches.

Potential effects of sialic acid and 3′-Sialyllactose on intestinal health and anti-cardiovascular disease in mice fed with a high-fat diet

This study investigated the beneficial effects of sialic acid (SA) and 3′-Sialyllactose (3′-SL) on the intestinal and cardiovascular health of mice fed with a high-fat diet. Male C57BL/6J mice were administered 0.9 % NaCl, SA, or 3′-SL by gavage throughout the experiment. After eight weeks, the ability of glucose regulation increased, the blood lipid decreased, the serum inflammatory factors decreased, and the SA content of low-density lipoprotein increased in the intervention groups. Transcriptome analysis of the small intestine and colon revealed gene expression patterns related to digestion, absorption, immunity, and the circadian rhythm. Metabonomic analysis of colon contents corroborated the findings of colonic transcriptomics.. The gut microbiome was characterised by an increase in beneficial bacteria and a decrease in harmful bacteria, which correlated with the blood lipid concentration. This study highlights the potential effects of SA and 3′-SL on intestinal health and anti-cardiovascular disease.

SpatialSPM: statistical parametric mapping for the comparison of gene expression pattern images in multiple spatial transcriptomic datasets.

Spatial transcriptomic (ST) techniques help us understand the gene expression levels in specific parts of tissues and organs, providing insights into their biological functions. Even though ST dataset provides information on the gene expression and its location for each sample, it is challenging to compare spatial gene expression patterns across tissue samples with different shapes and coordinates. Here, we propose a method, SpatialSPM, that reconstructs ST data into multi-dimensional image matrices to ensure comparability across different samples through spatial registration process. We demonstrated the applicability of this method by kidney and mouse olfactory bulb datasets as well as mouse brain ST datasets to investigate and directly compare gene expression in a specific anatomical region of interest, pixel by pixel, across various biological statuses. Beyond traditional analyses, SpatialSPM is capable of generating statistical parametric maps, including T-scores and Pearson correlation coefficients. This feature enables the identification of specific regions exhibiting differentially expressed genes across tissue samples, enhancing the depth and specificity of ST studies. Our approach provides an efficient way to analyze ST datasets and may offer detailed insights into various biological conditions.

Genome‑wide identification and expression analysis of the UBC gene family in wheat (Triticum aestivum L.)

BackgroundUbiquitination is an important regulatory step of selective protein degradation in the plant UPS (ubiquitin–proteasome system), which is involved in various biological processes in eukaryotes. Ubiquitin-conjugating enzymes play an intermediate role in the process of protein ubiquitination reactions and thus play an essential role in regulating plant growth and response to adverse environmental conditions. However, a genome-wide analysis of the UBC gene family in wheat (Triticum aestivum L.) has not yet been performed.ResultsIn this study, the number, physiochemical properties, gene structure, collinearity, and phylogenetic relationships of TaUBC family members in wheat were analyzed using bioinformatics methods. The expression pattern of TaUBC genes in different tissues/organs and developmental periods, as well as the transcript levels under abiotic stress treatment, were analyzed using RNA-Seq data and qRT-PCR. Meanwhile, favorable haplotypes of TaUBC25 were investigated based on wheat resequencing data of 681 wheat cultivars from the Wheat Union Database. The analyses identified a total of 93 TaUBC family members containing a UBC domain in wheat genome. These genes were unevenly distributed across 21 chromosomes, and numerous duplication events were observed between gene members. Based on phylogenetic analysis, the TaUBC family was divided into 13 E2 groups and a separate UEV group. We investigated the expression of TaUBC family genes under different tissue/organ and stress conditions by quantitative real-time PCR (qRT-PCR) analysis. The results showed that some TaUBC genes were specifically expressed in certain tissues/organs and that most TaUBC genes responded to NaCl, PEG6000, and ABA treatment with different levels of expression. In addition, we performed association analysis for the two haplotypes based on key agronomic traits such as thousand-kernel weight (TKW), kernel length (KL), kernel weight (KW), and kernel thickness (KT), examining 122 wheat accessions at three environmental sites. The results showed that TaUBC25-Hap II had significantly higher TKW, KL, KW, and KT than TaUBC25-Hap I. The distribution analysis of haplotypes showed that TaUBC25-Hap II was preferred in the natural population of wheat.ConclusionOur results identified 93 members of the TaUBC family in wheat, and several genes involved in grain development and abiotic stress response. Based on the SNPs detected in the TaUBC sequence, two haplotypes, TaUBC25-Hap I and TaUBC25-Hap II, were identified among wheat cultivars, and their potential value for wheat breeding was validated by association analysis. The above results provide a theoretical basis for elucidating the evolutionary relationships of the TaUBC gene family and lay the foundation for studying the functions of family members in the future.

Unraveling the regulatory landscape of Parkinson disease: A molecular symphony of miRNAs, transcription factors, and high-risk genes

MicroRNAs (miRNAs) have emerged as critical regulators of post-transcriptional gene expression, impacting various biological processes (development, differentiation, and progression). In medicine, miRNAs are promising diagnostic biomarkers for neurodegenerative diseases, including Parkinson's disease (PD). The current study aims at exploring the role of miRNAs and transcription factors (TFs) in regulating genes-associated with PD. Deploying bioinformatics tools, the study identifies specific miRNAs and TFs involved in PD and their potential connections to the organ-disease junction. Notably, certain miRNAs are found to be highly expressed in brain, than compared to blood. Furthermore, the study explores the expression patterns of PD-related genes in different regions of the brain and attempts to construct complex network of interactions contributing to PD pathogenesis. Additionally, the regulatory relationship of two miRNAs namely hsa-miR-375-3p and hsa-miR-423-3p with TFs are well examined. Overall, the study provides a comprehensive moon-shot view of the molecular aspects of PD and their potential therapeutic targets which could be further used as diagnostic biomarkers in early detection, drug design and development attributing towards precision medicine.

Duplicate Gene Expression and Possible Mechanisms of Paralog Retention During Bacterial Genome Expansion.

Gene duplication contributes to the evolution of expression and the origin of new genes, but the relative importance of different patterns of duplicate gene expression and mechanisms of retention remains debated and particularly poorly understood in bacteria. Here, we investigated gene expression patterns for two lab strains of the cyanobacterium Acaryochloris marina with expanding genomes that contain about 10-fold more gene duplicates compared with most bacteria. Strikingly, we observed a generally stoichiometric pattern of greater combined duplicate transcript dosage with increased gene copy number, in contrast to the prevalence of expression reduction reported for many eukaryotes. We conclude that increased transcript dosage is likely an important mechanism of initial duplicate retention in these bacteria and may persist over long periods of evolutionary time. However, we also observed that paralog expression can diverge rapidly, including possible functional partitioning, for which different copies were respectively more highly expressed in at least one condition. Divergence may be promoted by the physical separation of most Acaryochloris duplicates on different genetic elements. In addition, expression pattern for ancestrally shared duplicates could differ between strains, emphasizing that duplicate expression fate need not be deterministic. We further observed evidence for context-dependent transcript dosage, where the aggregate expression of duplicates was either greater or lower than their single-copy homolog depending on physiological state. Finally, we illustrate how these different expression patterns of duplicated genes impact Acaryochloris biology for the innovation of a novel light-harvesting apparatus and for the regulation of recA paralogs in response to environmental change.

Orchestration Of Photosynthesis-associated Gene Expression And Galactolipid Biosynthesis During Chloroplast Differentiation In Plants.

The chloroplast thylakoid membrane is composed of membrane lipids and photosynthetic protein complexes, and orchestration of thylakoid lipid biosynthesis and photosynthesis-associated protein accumulation is considered important for thylakoid development. Galactolipids consist of ~80% of the thylakoid lipids and their biosynthesis is fundamental for chloroplast development. We previously reported that the suppression of galactolipid biosynthesis decreased the expression of photosynthesis-associated nuclear- and plastid-encoded genes (PhANGs and PhAPGs). However, the mechanism for coordinative regulation between galactolipid biosynthesis in plastids and expression of PhANGs and PhAPGs remains largely unknown. To elucidate this mechanism, we investigated the gene expression patterns in galactolipid-deficient Arabidopsis seedlings during the deetiolation process. We found that galactolipids are crucial for inducing both the transcript accumulation of PhANGs and PhAPGs and the accumulation of plastid-encoded photosynthesis-associated proteins in developing chloroplasts. Genetic analysis indicates the contribution of GENOMES UNCOUPLED1 (GUN1)-mediated plastid-to-nucleus signaling pathway for PhANG regulation in response to galactolipid levels. Previous studies suggested that the accumulation of GUN1 reflects the state of protein homeostasis in plastids and alters the PhANG expression level. Thus we propose a model that galactolipid biosynthesis determines the protein homeostasis in plastids at the initial phase of deetiolation and optimizes the GUN1-dependent signaling to regulate the PhANG expression. This mechanism might contribute to orchestrating the biosynthesis of lipids and proteins for the biogenesis of functional chloroplasts in plants.

Effect of metabolically divergent pig breeds and tissues on mesenchymal stem cell expression patterns during adipogenesis

BackgroundUnraveling the intricate and tightly regulated process of adipogenesis, involving coordinated activation of transcription factors and signaling pathways, is essential for addressing obesity and related metabolic disorders. The molecular pathways recruited by mesenchymal stem cells (MSCs) during adipogenesis are also dependent on the different sources of the cells and genetic backgrounds of donors, which contribute to the functional heterogeneity of the stem cells and consequently affect the developmental features and fate of the cells.MethodsIn this study, the alteration of transcripts during differentiation of synovial mesenchymal stem cells (SMSCs) derived from fibrous synovium (FS) and adipose synovial tissue (FP) of two pig breeds differing in growth performance (German Landrace (DL)) and fat deposition (Angeln Saddleback (AS)) was investigated. SMSCs from both tissues and breeds were stimulated to differentiate into adipocytes in vitro and sampled at four time points (day 1, day 4, day 7 and day 14) to obtain transcriptomic data.ResultsWe observed numerous signaling pathways related to the cell cycle, cell division, cell migration, or cell proliferation during early stages of adipogenesis. As the differentiation process progresses, cells begin to accumulate intracellular lipid droplets and changes in gene expression patterns in particular of adipocyte-specific markers occur. PI3K-Akt signaling and metabolic pathways changed most during adipogenesis, while p53 signaling and ferroptosis were affected late in adipogenesis. When comparing MSCs from FS and FP, only a limited number of differentially expressed genes (DEGs) and enriched signaling pathways were identified. Metabolic pathways, including fat, energy or amino acid metabolism, were highly enriched in the AS breed SMSCs compared to those of the DL breed, especially at day 7 of adipogenesis, suggesting retention of the characteristic metabolic features of their original source, demonstrating donor memory in culture. In contrast, the DL SMSCs were more enriched in immune signaling pathways.ConclusionsOur study has provided important insights into the dynamics of adipogenesis and revealed metabolic shifts in SMSCs associated with different cell sources and genetic backgrounds of donors. This emphasises the critical role of metabolic and genetic factors as important indications and criteria for donor stem cell selection.

Characterization of sequences, expression profiling, and natural allelic variation analysis of the MYC gene family in sorghum (Sorghum bicolor)

Sorghum aphid (Melanaphis sacchari) and head smut fungi (Sporisorium reilianum) infesting sorghum cause delayed growth and development, and reduce yield and quality. This study use bioinformatics and molecular biological approaches to profile the gene expression pattern during sorghum development and under pest infestation, and analyzed the natural allelic DNA variation of sorghum MYC gene family. The findings provide insights for potential application in breeding the stress resistant and high productivity sorghum varieties. The results indicated that there are 28 MYC genes identified in sorghum genome, distributed on 10 chromosomes. The bHLH_MYC_N and HLH domains are the conserved domains of the MYC gene in sorghum. Gene expression analysis showed that SbbHLH35.7g exhibited high expression levels in leaves, SbAbaIn showed strong expression in early grains, and SbMYC2.1g showed high expression levels in mature pollen. In anti-aphid strains at the 5-leaf stage, SbAbaIn, SbLHW.4g and SbLHW.2g were significantly induced in leaves, while SbbHLH35.7g displayed the highest expression level in panicle tissue, which was significantly induced by the infection of head smut. Promoter cis-element analysis identified methyl jasmonate (MJ), abscisic acid (ABA), salicylic acid (SA) and MYB-binding sites related to drought-stress inducibility. Furthermore, genomic resequencing data analysis revealed natural allelic DNA variations such as single nucleotide polymorphism (SNP) and insertion-deletion (INDEL) for the key SbMYCs. Protein interaction network analysis using STRING indicated that SbAbaIn interacts with TIFYdomain protein, and SbbHLH35.7g interacts with MDR and imporin. SbMYCs exhibited temporal and spatial expression patterns and played vital roles during the sorghum development. Infestation by sugarcane aphids and head smut fungi induced the expression of SbAbaIn and SbbHLH35.7g, respectively. SbAbaIn modulated the jasmonic acid (JA) pathway to regulate the expression of defensive genes, conferring resistance to insects. On the other hand, SbbHLH35.7g participated in detoxification reactions to defend against pathogens.

Establishment of a prognostic risk model for osteosarcoma and mechanistic investigation.

Objective: To investigate the immune mechanism of osteosarcoma (OS)-specific markers to mitigate bone destruction in the aggressive OS, prone to recurrence and metastasis. Methods: Gene expression patterns from the Gene Expression Omnibus (GEO) database (GSE126209) were analyzed using weighted gene co-expression network analysis (WGCNA), protein-protein interaction (PPI) analysis, least absolute shrinkage and selection operator (LASSO) modeling, and survival analysis to identify charged multivesicular body protein 4C (CHMP4C). Subsequently, its role in regulating the immune system and immune cell infiltration was explored. CHMP4C expression and signaling molecules in OS were assessed in osteosarcoma cell lines (MG63, U2OS, HOS) and hFOB1.19 cells using reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and immunofluorescence staining. The impact of CHMP4C upregulation and interference on OS-related signaling molecules in MG63 cells was studied. Functional validation of CHMP4C in MG63 OS cells was confirmed through cell counting Kit-8 (CCK-8), transwell, and colony formation assays. In vivo experiments were conducted using Specific Pathogen Free (SPF)-grade male BALB/C nude mice for OS xenograft studies. Results: Based on the gene expression profiles analysis of six osteosarcoma samples and six normal tissue samples, we identified 1,511 upregulated DEGs and 5,678 downregulated DEGs in normal tissue samples. A significant positive correlation between the "yellow-green" module and OS was found through WGCNA analysis. Expression levels of CHMP4C, phosphorylated Glycogen Synthase Kinase 3β (p-GSK3β), and β-catenin were notably higher in U2OS, HOS, and MG63 OS cells than in hFOB1.19 human osteoblasts. Overexpressing CHMP4C in MG63 OS cells upregulated CHMP4C, p-GSK3β, and β-catenin while downregulating GSK3β, leading to increased proliferation and migration of MG63 cells. Conversely, interrupting CHMP4C had the opposite effect. High expression of CHMP4C significantly accelerated the growth of OS in nude mice, resulting in substantial upregulation of CHMP4C, p-GSK3β, and β-catenin expression and suppression of Glycogen Synthase Kinase 3β (GSK3β) expression in OS tissues. Conclusion: CHMP4C may serve as a specific immunomodulatory gene for OS. Its activation of the Wnt/β-catenin signaling pathway, mainly by increasing the phosphorylation echelon of GSK3β, promotes the invasion and spread of OS.

Unraveling the dynamic transcriptomic changes during the dimorphic transition of Talaromyces marneffei through time-course analysis.

Systemic dimorphic fungi pose a significant public health challenge, causing over one million new infections annually. The dimorphic transition between saprophytic mycelia and pathogenic yeasts is strongly associated with the pathogenesis of dimorphic fungi. However, despite the dynamic nature of dimorphic transition, the current omics studies focused on dimorphic transition primarily employ static strategies, partly due to the lack of suitable dynamic analytical methods. We conducted time-course transcriptional profiling during the dimorphic transition of Talaromyces marneffei, a model organism for thermally dimorphic fungi. To capture non-uniform and nonlinear transcriptional changes, we developed DyGAM-NS (dynamic optimized generalized additive model with natural cubic smoothing). The performance of DyGAM-NS was evaluated by comparison with seven other commonly used time-course analysis methods. Based on dimorphic transition induced genes (DTIGs) identified by DyGAM-NS, cluster analysis was utilized to discern distinct gene expression patterns throughout dimorphic transitions of T. marneffei. Simultaneously, a gene expression regulatory network was constructed to probe pivotal regulatory elements governing the dimorphic transitions. By using DyGAM-NS, model, we identified 5,223 DTIGs of T. marneffei. Notably, the DyGAM-NS model showcases performance on par with or superior to other commonly used models, achieving the highest F1 score in our assessment. Moreover, the DyGAM-NS model also demonstrates potential in predicting gene expression levels throughout temporal processes. The cluster analysis of DTIGs suggests divergent gene expression patterns between mycelium-to-yeast and yeast-to-mycelium transitions, indicating the asymmetrical nature of two transition directions. Additionally, leveraging the identified DTIGs, we constructed a regulatory network for the dimorphic transition and identified two zinc finger-containing transcription factors that potentially regulate dimorphic transition in T. marneffei. Our study elucidates the dynamic transcriptional profile changes during the dimorphic transition of T. marneffei. Furthermore, it offers a novel perspective for unraveling the underlying mechanisms of fungal dimorphism, emphasizing the importance of dynamic analytical methods in understanding complex biological processes.

Conserved and specific gene expression patterns in the embryonic development of tardigrades.

Tardigrades, commonly known as water bears, are enigmatic organisms characterized by their remarkable resilience to extreme environments despite their simple and compact body structure. To date, there is still much to understand about their evolutionary and developmental features contributing to their special body plan and abilities. This research provides preliminary insights on the conserved and specific gene expression patterns during embryonic development of water bears, focusing on the species Hypsibius exemplaris. The developmental dynamic expression analysis of the genes with various evolutionary age grades indicated that the mid-conserved stage of H. exemplaris corresponds to the period of ganglia and midgut development, with the late embryonic stage showing a transition from non-conserved to conserved state. Additionally, a comparison with Drosophila melanogaster highlighted the absence of certain pathway nodes in development-related pathways, such as Maml and Hairless, which are respectively the transcriptional co-activator and co-repressor of NOTCH regulated genes. We also employed Weighted Gene Co-expression Network Analysis (WGCNA) to investigate the expression patterns of tardigrade-specific genes during embryo development. Our findings indicated that the module containing the highest proportion of tardigrade-specific genes (TSGs) exhibits high expression levels before the mid-conserved stage, potentially playing a role in glutathione and lipid metabolism. These functions may be associated to the ecdysone synthesis and storage cell formation, which is unique to tardigrades.

P155 Gene expression in hypermobility and the role of inflammation

Abstract Background/Aims Hypermobile conditions, including Ehlers-Danlos syndrome and joint hypermobility syndrome, encompass a broad spectrum of heterogenous clinical entities characterised by excessive range of joint movements and variable extra-articular features. The etiological basis of these conditions is thought to relate to abnormal collagen assembly, which impairs the structural integrity of connective tissue, although precise mechanisms remain both debated and incompletely understood. Despite the established strong heritability of hypermobility, a definitive genetic cause remains unidentifiable in most hypermobile patients, highlighting the need to further characterize the genetic landscape of hypermobile conditions. In this study, we therefore employ transcriptomic analysis as an alternate means of elucidating the genetic basis of hypermobility. Methods We tested for the effects of hypermobility on gene expression, at baseline and following an inflammatory challenge, by re-analysing existing transcriptomic data gathered from healthy subjects and patients with fibromyalgia and chronic fatigue using total RNA sequencing of blood samples (Illumina NextSeq 500). From each participant, two blood samples were taken on separate occasions: one after a saline injection and the other after an inflammatory challenge, the typhoid vaccination, in a cross-over design. Participants were assigned to hypermobile or non-hypermobile conditions in accordance with criterion 1: generalized joint hypermobility of the Diagnostic Criteria for Hypermobile Ehlers-Danlos Syndrome (hEDS) produced by the International Consortium on Ehlers-Danlos Syndromes & Related disorders. Differential gene expression analysis comparing hypermobile and non-hypermobile participants was performed using EdgeR software in R studio. Baseline differences were determined by comparing post-saline samples between groups. Differential responses to the inflammatory challenge were detected by comparison of post-typhoid samples between groups. Gene ontology on differentially expressed genes was performed using DAVID’s Functional Annotation Clustering tool. Results We found 288 differentially expressed genes post-saline (i.e at baseline) and 1113 post-typhoid at p < 0.05 although none passed false discovery rate. At baseline, differentially expressed genes were significantly enriched for nuclear, endoplasmic reticulum, and microtubular genes (enrichment score = 2.96, 2.02, 1.3 respectively); and post-typhoid, for 24 clusters, the three most significant being synaptic, ion transport, and plasma membrane genes (enrichment score = 11.34, 8.71, and 7.3 respectively). Conclusion These data demonstrate distinct patterns of gene expression, both at baseline and during inflammation, which implicate potential biological pathways in the pathophysiology of hypermobility. These results also contribute to a growing understanding of the genetic basis of hypermobility and may inform future higher-powered studies to validate our findings. Disclosure J. Porter: None. M. Amato: None. K. Themelis: None. H. Critchley: None. S. Newbury: None. K. Davies: None. N. Harrison: None. B. Towler: None. J. Eccles: Grants/research support; J.E. has received funding from Versus Arthritis, National Institute for Health Research and the Fibroduck Foundation.

Population-level immunologic variation in wild threespine stickleback (Gasterosteusaculeatus)

Wild organisms are regularly exposed to a wide range of parasites, requiring the management of an effective immune response while avoiding immunopathology. Currently, our knowledge of immunoparasitology primarily derives from controlled laboratory studies, neglecting the genetic and environmental diversity that contribute to immune phenotypes observed in wild populations. To gain insight into the immunologic variability in natural settings, we examined differences in immune gene expression of two Alaskan stickleback (Gasterosteus aculeatus) populations with varying susceptibility to infection by the cestode Schistocephalus solidus. Between these two populations, we found distinct immune gene expression patterns at the population level in response to infection with fish from the high-infection population displaying signs of parasite-driven immune manipulation. Further, we found significant differences in baseline immune gene profiles between the populations, with uninfected low-infection population fish showing signatures of inflammation compared to uninfected high-infection population fish. These results shed light on divergent responses of wild populations to the same parasite, providing valuable insights into host-parasite interactions in natural ecosystems.

The expansion of oligopeptide transporters in Melampsora larici-populina may reflect its adaptation to a phytoparasitic lifestyle

The acquisition of nutrients from host plants by phytopathogenic fungi is critically important for their invasion success. Melampsora larici-populina, an obligate biotrophic pathogenic fungus, causes the poplar leaf rust disease and can severely damage host poplar plants. Previously, we found that oligopeptide transporters (OPTs) have undergone a convergent expansion, which might reflect adaptation to a phytoparasitic lifestyle. Here, we used various methods to evaluate this hypothesis, including conserved motif identification, positive selection signal mining, expression pattern clustering analysis, and neutral selection tests. The motif composition of the five clades in the OPT family differed, and positive selection was observed during clade differentiation. This suggests that OPTs in these five clades may be functionally differentiated, which would increase the range of transported substrates and promote the absorption of more types of nitrogen compounds from the hosts. According to clustering analysis of gene expression patterns, the expression of most genes from the two expanded clades (clade 2 and 4) was up-regulated during the infection of poplar trees, indicating that the expansion of OPTs likely occurred to promote the uptake of oligopeptides from host poplar plants. The MellpOPT4g gene was determined to be under significant balancing selection based on the neutral selection tests, suggesting that it plays a role in the pathogenic process. In conclusion, these three observations provide preliminary evidence supporting our hypothesis, as they indicate that the expansion of OPTs in M. larici-populina has aided the ability of this pathogen to acquire nutrients from host plants.

P180 RNA sequencing of regulatory T cells sorted from Rheumatoid Arthritis peripheral blood

Abstract Background/Aims In the presence of an inflammatory environment, regulatory T cells (Tregs) have the ability to adopt an effector T helper(Th)-like phenotype, enabling them to produce pro-inflammatory cytokines, particularly IFN-γ (resembling Th1-like Tregs) and IL-17(resembling Th17-like Tregs). This adaptability of Tregs may be driven by the increased activation of effector pathways. In order to unveil distinct gene expression patterns while simultaneously characterizing Tregs based on their phenotype, we did RNA sequencing of sorted Tregs from the peripheral blood(PB) of individuals with rheumatoid arthritis(RA), osteoarthritis(OA), and healthy controls(HC). Methods Phenotyping of Tregs, Tregs expressing CXCR3(Th1-like Treg), CCR6(Th17-like Treg) from PB and synovial fluid(SF) of RA(n = 20 each), OA(n = 20 each) and HC (n = 20) was done using flow cytometry. Cell frequencies between the groups were compared using Student t test or one-way ANOVA (Tukey's post hoc Test) as appropriate; p < 0.05 was considered as statistically significant. RNA was extracted from the sorted PB Tregs of RA, OA and HC(n = 3 each) and was sequenced using Illumina Novaseq 6000 platform. Sample clustering was done using principal component analysis generated using DeSeq2. Genes were categorized as upregulated or downregulated based on their log2 fold change cut off of 2. Significantly upregulated and downregulated differentially expressed genes (DEGs) were shortlisted using a false discovery rate(FDR) corrected p-value cut-off of ≤ 0.05. Heatmaps and volcano plots were generated using R package. Functional pathway enrichment analysis was done using GO and KEGG software. Results Proportion of Tregs in the PB of RA was significantly lower than OA and HC. This difference was not observed in the SF. Both RA PB and SF exhibited higher percentages of Th1 and Th17-like Tregs when compared to OA and HC (Table 1A).DEG analysis revealed altered gene regulation in RA Tregs compared to Tregs from HC and OA. Compared to HC, genes related to TCR signaling, cytokine signaling, and chemokine signaling pathways were enriched in RA. In contrast, compared to OA, an upregulation of pathway genes such as NR4A1(PI3K-Akt signaling), and TNFRSF1B(TNF signaling) was noted in RA. Furthermore, genes associated with Th1 differentiation and activation (IFNGR1, IL12RB1, STAT4) and genes associated with Th17 profile(RORC, STAT3, IL6R, IL17B) were upregulated in RA relative to HC and but not in OA compared to to HC.(Table 1B). Additionally, genes involved in glucose metabolism, purine metabolism, oxidative phosphorylation, and pyrimidine metabolism exhibited distinct patterns of regulation in RA. Conclusion Our Treg phenotyping data shows that there is higher conversion of Tregs into Th1 and Th17 like Tregs in RA and transcriptome data indicates cytokine(IFNγ, IL-6, IL-12 & IL-17) mediated transcriptional changes likely drove the conversion of Tregs towards Th1 and Th17 phenotype. Our data also suggests a possible metabolic re-programming of Tregs towards an inflammatory phenotype affecting its stability. Disclosure V. Kommoju: None. C. mariaselvam: None. S. Vembar: None. S. Bulusu: None. C. Kavadichanda: None. M. Thabah: None. V. Negi: None.

Emergence of enhancers at late DNA replicating regions

Enhancers are fast-evolving genomic sequences that control spatiotemporal gene expression patterns. By examining enhancer turnover across mammalian species and in multiple tissue types, we uncover a relationship between the emergence of enhancers and genome organization as a function of germline DNA replication time. While enhancers are most abundant in euchromatic regions, enhancers emerge almost twice as often in late compared to early germline replicating regions, independent of transposable elements. Using a deep learning sequence model, we demonstrate that new enhancers are enriched for mutations that alter transcription factor (TF) binding. Recently evolved enhancers appear to be mostly neutrally evolving and enriched in eQTLs. They also show more tissue specificity than conserved enhancers, and the TFs that bind to these elements, as inferred by binding sequences, also show increased tissue-specific gene expression. We find a similar relationship with DNA replication time in cancer, suggesting that these observations may be time-invariant principles of genome evolution. Our work underscores that genome organization has a profound impact in shaping mammalian gene regulation.