Biology subjects

Guryev, V.

Publications and source records attributed to Guryev, V..

At least 19 recordsLinked to original sources

bioRxiv2026

PUMA: A Phenotypic Unsupervised Model of Aging Reveals Distinct Aging Dimensions

Aging is a multidimensional process, yet most aging models reduce it to a single score to estimate biological aging and predict health outcomes, disease risk, or mortality. Here, we introduce PUMA (Phenotypic Unsupervised Model of Aging), a framework that characterizes aging through multiple phenotypic dimensions. Applying PUMA to more than 1,000 traits spanning behavioral, psychological, social, physical, environmental, and biomedical domains in over 150,000 individuals from the Lifelines cohort, we identified seven distinct phenotypic aging dimensions. These dimensions were significantly associated with the future incidence of major age-related diseases--including cancer, diabetes, COPD, heart failure, stroke, and Parkinsons disease-- demonstrating the potential of PUMA to stratify individuals by disease risk and identify phenotypic domains for targeted intervention. Notably, dimensions reflecting psychosocial factors, particularly cumulative life stress, predicted disease risk as strongly as, or more strongly than, traditional biomedical risk factors, highlighting the importance of psychological and social influences in aging and disease risk. The observation that phenotypic aging dimensions are differentially associated with the future risk of age-related diseases supports a multidimensional model of aging, indicating that aging is not a single uniform process. Because PUMA relies on accessible phenotypic data, it provides an interpretable framework for disease risk stratification and targeted preventive strategies.

bioinformatics↗

bioRxiv2026

In garden dormouse cerebral cortex, specific transcriptional programs exist for all major phases of hibernation

Hibernators cycle between torpor, a state of profound metabolic and thermoregulatory suppression, and brief arousals during which metabolic rate and body temperature rapidly return to euthermic levels. These repeated physiological pressures require robust mechanisms to preserve brain integrity. Because the cerebral cortex is not thought to control hibernation directly yet must remain viable throughout torpor and recover rapidly during arousal, it provides a useful model for studying neural adaptation to hibernation. We therefore performed RNA sequencing of cerebral cortex from garden dormice (Eliomys quercinus) sampled during summer euthermia (SE), early torpor (TE), late torpor (TL), early arousal (AE), and late arousal (AL). Differential expression analysis revealed strongly stage-specific transcriptional remodeling across the hibernation cycle. Entry into torpor (SE-TE) and the transition from early to late arousal (AE-AL) showed minimal change, with 16 and 2 differentially expressed genes (DEGs), respectively. In contrast, extensive regulation was observed during torpor progression (TE-TL; 576 DEGs) and especially during the transition from late torpor to early arousal (TL-AE; 697 DEGs). Intermediate numbers of DEGs were detected in AL-TE (260) and AL-SE (50). Principal component and enrichment analyses indicated that the dominant axes of variation were associated with RNA processing and proteostatic control, metabolic and redox-related adaptation, and changes in intracellular trafficking and protein handling. In addition, comparison of adjacent contrasts revealed a marked opposite-direction transcriptional reversal between TE-TL and TL-AE, consistent with coordinated reactivation of torpor-associated programs during arousal. Together, these findings support a model in which cortex adaptation to hibernation involves transcriptional reprogramming consistent with metabolic suppression during torpor progression, especially in pathways related to carbohydrate and central carbon metabolism, redox homeostasis, and cellular signalling, followed by rapid reversal of these programs during early arousal.

molecular biology↗

bioRxiv2024

Single-cell X-chromosome inactivation analysis links biased chimerism to differential gene expression and epigenetic erosion

Female cells randomly inactivate one X-chromosome, resulting in cellular mosaicism. Determining the bias in X-chromosomal inactivation (XCI) at single cell level may be relevant for understanding diseases prevalent in females. Here, we introduce a computational method that determines XCI profiles at single-cell level using solely sc/snRNA-Seq data. XCI analysis of skin cells from hybrid mice validates our approach and reveals biased inactivation of X-chromosomes among cell types. In human lung and brain cells, XCI status can be determined in 33.8% and 23.6% of cells. Among the patients, cells with opposite inactivation patterns differently express members of specific gene families and pathways. Alzheimers disease patients show reversal of XCI in cortical microglia and regional increase in biallelic expression denoting epigenetic erosion. We provide a robust utility to explore the degree and impact of XCI in single cell expression data.

bioinformatics↗

bioRxiv2023

Ancestral genomes and population sequencing data reveal strand- and context-specificityof polymorphic G4 sites

Recent studies highlight the important functional roles of non-canonical DNA conformations. One of such structures, G-quadruplex (G4), was shown to be involved in multiple processes within a cell such as telomere maintenance, gene regulation, protein translation and alternative splicing. On the other hand, DNA in non-double stranded context can hinder replication and repair processes and, indeed, a higher rate of polymorphisms was reported at G4 sites. However, strand-specificity, positional and nucleotide contexts of nucleotide substitutions at G4 sites are under-investigated. Here, we combine ancestral genome data and DNA variants from large populational sequencing project to investigate substitution patterns within putative DNA quadruplexes. We confirm the overall elevated rate of base replacement except transitions at CpG sites, which are less likely than in the rest of the genome potentially due to hypomethylated status of G4s. Within G4 loops, there is a trend of replacing weak bases (A, T) with strong bases (G, C) that could promote DNA duplex stabilization. However, this trend is less pronounced when derived allele is rare in the human population. The most over-represented thymine to guanine replacement is about order of magnitude more frequent within G4 than in non-G4 regions. The analysis of nucleotide context of the substitutions shows clear difference between G-rich and C-rich of DNA quadruplexes implying that the strands of the quadruplex might have different mutation dynamics. Finally, we show that the observed deviations from random mutation accumulation result in a biased nucleotide composition of G4 loops rich in adenines. Future studies should reveal specific mutation and selection processes that shape the content of G4-associated DNA polymorphisms.

genomics↗

bioRxiv2023

A dynamic bias in chromatin protein deposition at G-quadruplex sites

Previous studies indicate that genomic loci harboring G-quadruplexes (G4s)--stacked structures that can form in single-stranded DNA--can be linked to epigenetic instability. However, the role of chromatin redistribution and the genome-wide nature of this process need further investigation. Here, we provide experimental evidence that connects G4s to alterations in the deposition of chromatin proteins. We have used metabolic labelling and immunoprecipitation of new and parental proteins in hRPE-1 cells to investigate global chromatin deposition dynamics. We identify a reciprocal, local bias in chromatin protein deposition at G4 sites favoring the association of parental proteins with the G4 and new proteins with the C4 DNA strand. The deposition bias at G4 sites does not depend on replication directionality and is strengthened by G4 stabilization. Slowing down replication forks upon hydroxyurea treatment reverses the bias, supposedly affected by decoupling between helicase and polymerase. Interestingly, upon combined G4 stabilization and slowing of the replication forks, new proteins exhibit a redistribution pattern similar to G4 stabilization alone, while parental protein redistribution more resembles one after hydroxyurea treatment, hinting at mechanistic differences between parental and new histone distribution. We also report that the genomic distribution of putative quadruplexes is not random and depends on loop size, where G4s with shorter loops have a preference for the DNA strand replicated by leading and G4s with longer loops by lagging strand replication. These findings provide insight into the mechanisms behind G4 occurrence and its role in epigenetic instability and help to improve our understanding of the factors influencing biases in global chromatin protein redeposition.

molecular biology↗

bioRxiv2023

Local G-quadruplexes are not a major determinant of altered gene expression in BLM-deficientcells

Mutations in the Blm gene can cause Bloom Syndrome, a genetic disorder characterized by genome instability and cancer predisposition. Blm encodes a helicase which was reported to resolve G-quadruplex DNA structures in vitro. The G-quadruplex resolving activity of the BLM helicase has been previously implicated in altering gene expression. However, the exact mechanisms of how G-quadruplex structures may affect gene expression remain to be elucidated. We employed experimentally defined G-quadruplex forming DNA sequences and generated transcriptomes for several Bloom Syndrome patient-derived cell lines and BLM-deficient mouse embryonic stem cells to further investigate the effect of G-quadruplexes on gene expression. Our results do not support the previous findings that G-quadruplexes located within a gene play a major role in altering its expression in BLM-deficient cells. We found concerted large-scale changes in transcript abundance, splicing, nucleosome occupancy, and phasing, that cannot be linked to the local presence of G-quadruplex sequences in either gene bodies or promotors. The investigation of genomic features associated with large-scale differences in nucleosome density highlights the rDNA locus and active enhancers as the most strongly affected regions. We hypothesize that global changes in chromatin structure rather than local G4s might mediate the transcriptome changes in the absence of BLM.

molecular biology↗

bioRxiv2023

Cellular Senescence Affects ECM Regulation in COPD Lung Tissue

IntroductionHigher levels of cellular senescence have been demonstrated in COPD patients, including severe early-onset (SEO)-COPD. Recently, we demonstrated that senescence induces extracellular matrix (ECM) dysregulation in lung fibroblasts. However, this in vitro observation has not been demonstrated in vivo yet. Therefore, we investigated whether cellular senescence can contribute to COPD-associated ECM changes in parenchymal lung tissue. MethodsTranscriptomic and proteomic analyses were performed on parenchymal lung tissue from 60 COPD patients (including 18 SEO-COPD patients) and 32 controls. Differential expression of ECM-related genes and proteins was compared between (SEO-)COPD and controls, followed by correlations with six senescence markers and four senescence signature scores. Significant ECM-senescence correlations were verified using histology and primary lung fibroblasts. ResultsWe identified 12 COPD- and 57 SEO-COPD-associated ECM genes and 4 COPD- and 9 SEO-COPD-associated ECM proteins of which the majority, 45 genes and 5 proteins, correlated with senescence. The correlations for COL6A1, COL6A2 and FBLN5 were confirmed in situ and correlations for 21 ECM genes were confirmed in primary lung fibroblasts at baseline. Four genes were successfully functionally validated in our senescence-induced lung fibroblast model, including increased protein levels of ADAMST1 and a non-functional FBLN5 protein. ConclusionsWe confirm a strong link between (SEO-)COPD-associated ECM changes and senescence in vivo in peripheral lung tissue from COPD patients. The strongest and most consistent senescence-associated ECM components include proteases, elastogenesis genes, and collagens 6. These results indicate a contributing role for senescence in disturbed ECM and elastic fiber organization, and protease-antiprotease imbalance in COPD.

pathology↗

bioRxiv2023

A revamped rat reference genome improves the discovery of genetic diversity in laboratory rats

The seventh iteration of the reference genome assembly for Rattus norvegicus-- mRatBN7.2--corrects numerous misplaced segments and reduces base-level errors by approximately 9-fold and increases contiguity by 290-fold compared to its predecessor. Gene annotations are now more complete, significantly improving the mapping precision of genomic, transcriptomic, and proteomics data sets. We jointly analyzed 163 short-read whole genome sequencing datasets representing 120 laboratory rat strains and substrains using mRatBN7.2. We defined [~]20.0 million sequence variations, of which 18.7 thousand are predicted to potentially impact the function of 6,677 genes. We also generated a new rat genetic map from 1,893 heterogeneous stock rats and annotated transcription start sites and alternative polyadenylation sites. The mRatBN7.2 assembly, along with the extensive analysis of genomic variations among rat strains, enhances our understanding of the rat genome, providing researchers with an expanded resource for studies involving rats.

genomics↗

bioRxiv2022

Liver transcriptomic and methylomic analyses identify transcriptional MAPK regulation in facultative hibernation of Syrian hamster

Hibernation consist of alternating torpor/arousal phases, during which animals cope with repetitive hypothermia and ischemia-reperfusion. Due to limited transcriptomic and methylomic information for facultative hibernators, we here conducted RNA and whole genome bisulfite sequencing in liver of hibernating Syrian hamster (Mesocricetus auratus). Gene Ontology analysis was performed on 844 differentially expressed genes (DEGs) and confirmed the shift in metabolic fuel utilization, inhibition of RNA transcription and cell cycle regulation as found in seasonal hibernators. We show a so far unreported suppression of MAPK and PP1 pathways. Notably, hibernating hamsters showed upregulation of MAPK inhibitors (DUSPs and SPRYs) and reduced levels of MAPK induced transcription factors. Promoter methylation was found to modulate the expression of genes targeted by these transcription factors. In conclusion, we document gene regulation between hibernation phases, which may aid the identification of pathways and targets to prevent organ damage in transplantation or ischemia-reperfusion.

genomics↗

bioRxiv2022

IL-33 induced gene expression in activated Th2 effector cells is dependent on IL-1RL1 haplotype and disease status

BackgroundIL-33 can activate Th2 cells after binding to the IL-1RL1/IL-1RAcP receptor. However, it is unknown whether disease or genetic make-up regulate IL33 responsiveness of Th2 cells. ObjectiveWe investigated whether IL-1RL1 asthma risk haplotypes or asthma status influence IL-33-induced Th2 transcriptomic responses in vitro. MethodsCD4+ T cells from 16 asthma patients and matched controls, stratified for IL-1RL1 haplotype, were differentiated into Th2 effector cells, and re-stimulated in the presence or absence of IL-33, followed by RNA-sequencing and differential gene expression analysis. Association of IL-33-induced gene signatures with clinical parameters was tested in U-BIOPRED sputum transcriptomic data. ResultsPresence of IL-33 during Th2 cell re-stimulation results in extensive changes in gene expression, affecting a large proportion of the activated Th2 cell transcriptome. IL-33 induced more genes in Th2 cells from donors with asthma than in controls. However, the IL-33 effects were strongest in Th2 cells carrying the IL-1RL1 risk haplotype, as evidenced by a significantly increased effect size compared to controls. A gene signature of IL-33 induced genes in Th2 cells showed a strong positive correlation with macrophage counts and pauci-granulocytic asthma in sputum transcriptomic data from the U-BIOPRED study. ConclusionThe risk IL-1RL1 haplotype strongly increases the sensitivity of Th2 effector cell for IL-33-mediated regulation of gene expression, while asthma status has an independent effect. The IL-33 gene signature was not associated with type-2 high or eosinophilic asthma in sputum transcriptomic data from U-BIOPRED. Clinical OutcomeCellular sensitivity to IL-33 depends on genetic makeup and asthma disease status. Capsule summaryIL-33 strongly alters gene expression of activated Th2 cells, dependent on asthma disease status and IL-1RL1 risk haplotype. IL-33 driven gene signature in sputum transcriptomic data identifies pauci-granulocytic asthma.

molecular biology↗

bioRxiv2022

FastCAR: Fast Correction for Ambient RNA to facilitate differential gene expression analysis in single-cell RNA-sequencing datasets

Cell type-specific differential gene expression analyses based on single-cell transcriptome datasets are sensitive to the presence of cell-free mRNA in the droplets containing single cells. This so-called ambient RNA contamination may differ between samples obtained from patients and healthy controls. Current ambient RNA correction methods were not developed specifically for single-cell differential gene expression (sc-DGE) analyses and might therefore not sufficiently correct for ambient RNA-derived signals. Here, we show that ambient RNA levels are highly sample-specific. We found that without ambient RNA correction, sc-DGE analyses erroneously identify transcripts originating from ambient RNA as cell type-specific disease-associated genes. We therefore developed a computationally lean and intuitive correction method, Fast Correction for Ambient RNA (FastCAR), optimized for sc-DGE analysis of scRNA-Seq datasets generated by droplet-based methods including the 10XGenomics Chromium platform. FastCAR uses the profile of transcripts observed in libraries that likely represent empty droplets to determine the level of ambient RNA in each individual sample, and then corrects for these ambient RNA gene expression values. FastCAR can be applied as part of the data pre-processing and QC in sc-DGE workflows comparing scRNA-Seq data in a health versus disease experimental design. We compared FastCAR with two methods previously developed to remove ambient RNA, SoupX and CellBender. All three methods identified additional genes in sc-DGE analyses that were not identified in the absence of ambient RNA correction. However, we show that FastCAR performs better at correcting gene expression values attributed to ambient RNA, resulting in a lower frequency of false-positive observations. Moreover, the use of FastCAR in a sc-DGE workflow increases the cell-type specificity of sc-DGE analyses across disease conditions.

bioinformatics↗

bioRxiv2021

Sister chromatid exchanges induced by perturbed replication are formed independently of homologous recombination factors

Sister chromatid exchanges (SCEs) are products of joint DNA molecule resolution, and are considered to form through homologous recombination (HR). Indeed, upon generation of irradiation-induced DNA breaks, SCE induction was compromised in cells deficient for canonical HR factors BRCA1, BRCA2 and RAD51. Contrarily, replication-blocking agents, including PARP inhibitors, induced SCEs independently of BRCA1, BRCA2 and RAD51. PARP inhibitor-induced SCEs were enriched at common fragile sites (CFSs), and were accompanied by post-replicative single-stranded DNA (ssDNA) gaps. Moreover, PARP inhibitor-induced replication lesions were transmitted into mitosis, suggesting that SCEs originate from mitotic processing of under-replicated DNA. We found that DNA polymerase theta (POLQ) was recruited to mitotic DNA lesions, and loss of POLQ resulted in reduced SCE numbers and severe chromosome fragmentation upon PARP inhibition in HR-deficient cells. Combined, our data show that PARP inhibition generates under-replicated DNA, which is transferred into mitosis and processed into SCEs, independently of canonical HR factors.

cancer biology↗

bioRxiv2021

Inversion of asymmetric histone deposition upon replication stress

Following DNA replication, equal amounts of histones are distributed over sister chromatids by re-deposition of parental histones and deposition of newly synthesized histones. Molecular mechanisms balancing the allocation of new and old histones remain largely unknown. Here, we studied the genome-wide distribution of new histones relative to parental DNA template strands and replication initiation zones using double-click-seq. In control conditions, new histones were preferentially found on DNA replicated by the lagging strand machinery. Strikingly, replication stress induced by hydroxyurea or curaxin treatment, and inhibition of ATR or p53 inactivation, inverted the observed histone deposition bias to the strand replicated by the leading strand polymerase in line with previously reported effects on RPA occupancy. We propose that asymmetric deposition of newly synthesized histones onto sister chromatids reflects differences in the processivity of leading and lagging strand synthesis.

cell biology↗

bioRxiv2021

Proteogenomics Reveals how Metastatic Melanoma Modulates the Immune System to Allow Immune Evasion

Malignant melanoma (MM) develops from the melanocytes and in its advanced stage is the most aggressive type of skin cancer. Here we report a comprehensive analysis on a prospective cohort study, including non-tumor, primary and metastasis tissues (n=77) with the corresponding plasma samples (n=56) from patients with malignant melanoma. The tumors and surrounding tissues were characterized with a combination of high-throughput analyses including quantitative proteomics, phosphoproteomics, acetylomics, and whole exome sequencing (WES) combined with in-depth histopathology analysis. Melanoma cell proliferation highly correlates with dysregulation at the proteome, at the posttranslational- and at the transcriptome level. Some of the changes were also verified in the plasma proteome. The metabolic reprogramming in melanoma includes upregulation of the glycolysis and the oxidative phosphorylation, and an increase in glutamine consumption, while downregulated proteins involved in the degradation of amino acids, fatty acids, and the extracellular matrix (ECM) receptor interaction. The pathways most dysregulated in MM including the MAP kinases-, the PI3K-AKT signaling, and the calcium homeostasis, are among the most affected by mutations, thus, dysregulation in these pathways can be manifested as drivers in melanoma development and progression. The phosphoproteome analysis combined with target-based prediction mapped 75% of the human kinome. Melanoma cell proliferation was driven by two key factors: i) metabolic reprogramming leading to upregulation of the glycolysis and oxidative phosphorylation, supported by HIF-1 signaling pathway and mitochondrial translation; and ii) a dysregulation of the immune system response, which was mirrored by immune system processes in the plasma proteome. Regulation of the melanoma acetylome and expression of deacetylase enzymes discriminated between groups based on tissue origin and proliferation, indicating a way to guide the successful use of HDAC inhibitors in melanoma. The disease progression toward metastasis is driven by the downregulation of the immune system response, including MHC class I and II, which allows tumors to evade immune surveillance. Altogether, new evidence is provided at different molecular levels to allow improved understanding of the melanoma progression, ultimately contributing to better treatment strategies. TOC figure O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=157 SRC="FIGDIR/small/439245v1_ufig1.gif" ALT="Figure 1"> View larger version (58K): org.highwire.dtl.DTLVardef@937db9org.highwire.dtl.DTLVardef@1230b57org.highwire.dtl.DTLVardef@1bd889eorg.highwire.dtl.DTLVardef@547d90_HPS_FORMAT_FIGEXP M_FIG C_FIG

cancer biology↗

bioRxiv2021

The developmental stage of the medulloblastoma cell-of-origin restricts Hedgehog pathway usage and drug sensitivity

Sonic Hedgehog (SHH) medulloblastoma originates from the cerebellar granule neuron progenitor (CGNP) lineage that depends on Hedgehog signaling for its perinatal expansion. While SHH tumors exhibit overall deregulation of this pathway, they also show patient age-specific aberrations. To investigate if the developmental stage of the CGNP can account for these age-specific lesions, we analyzed developing murine CGNP transcriptomes and observed highly dynamic gene expression as function of age. Cross-species comparison with human SHH medulloblastoma showed partial maintenance of these expression patterns, and highlighted low primary cilium expression as hallmark of infant medulloblastoma and early embryonic CGNPs. This coincided with reduced responsiveness to upstream Shh pathway component Smoothened, while sensitivity to downstream components Sufu and Gli was retained. Together, these findings can explain the preference for SUFU mutations in infant medulloblastoma and suggest that drugs targeting the downstream SHH pathway will be most appropriate for infant patients.

cancer biology↗

bioRxiv2020

Whole genome sequencing of nearly isogeneic WMI and WLI inbred rats identifies genes potentially involved in depression

BackgroundThe WMI and WLI inbred rat substrains were generated from the stress-prone, and not yet fully inbred, Wistar Kyoto (WKY) strain using bi-directional selection for immobility in the forced swim test followed by over 38 generations of inbreeding. Despite the low level of genetic diversity among WKY progenitors, the WMI substrain is more vulnerable to stress relative to its WLI control substrain. Here we quantify numbers and classes of sequence variants distinguishing these substrains and test the hypothesis that they are nearly isogenic. ResultsThe WLI and WMI genomic DNA were sequenced using Illumina xTen, IonTorrent and 10X Chromium technologies to obtain a combined coverage of over 100X. We identified 4,296 high quality homozygous SNPs and indels that differ between the WMI and WLI substrains. Gene ontology analysis of these variants showed an enrichment for neurogenesis related pathways. In addition, high impact variations were detected in genes previously implicated in depression (e.g. Gnat2), depression-like behavior (e.g. Prlr, Nlrp1a), other psychiatric disease (e.g. Pou6f2, Kdm5a, Reep3, Wdfy3) or stress response (e.g. Pigr). ConclusionsThe high coverage sequencing data confirms the near isogenic nature of the two substrains, which combined with the variants detected can lead to the identification of genetic factors underlying greater susceptibility for depression, stress reactivity, and addiction.

bioinformatics↗

bioRxiv2020

Whole-genome sequencing of 1,171 elderly admixed individuals from the largest Latin American metropolis (Sao Paulo, Brazil)

As whole-genome sequencing (WGS) becomes the gold standard tool for studying population genomics and medical applications, data on diverse non-European and admixed individuals are still scarce. Here, we present a high-coverage WGS dataset of 1,171 highly admixed elderly Brazilians from a census-based cohort, providing over 76 million variants, of which ~2 million are absent from large public databases. WGS enabled identifying ~2,000 novel mobile element insertions, nearly 5Mb of genomic segments absent from human genome reference, and over 140 novel alleles from HLA genes. We reclassified and curated nearly four hundred variant's pathogenicity assertions in genes associated with dominantly inherited Mendelian disorders and calculated the incidence for selected recessive disorders, demonstrating the clinical usefulness of the present study. Finally, we observed that whole-genome and HLA imputation could be significantly improved compared to available datasets since rare variation represents the largest proportion of input from WGS. These results demonstrate that even smaller sample sizes of underrepresented populations bring relevant data for genomic studies, especially when exploring analyses allowed only by WGS.

genomics↗

bioRxiv2020

Discovery of pharmaceutically-targetable pathways and prediction of survivorship for pneumonia and sepsis patients from the view point of ensemble gene noise

Finding novel biomarkers for human pathologies and predicting clinical outcomes for patients is rather challenging. This stems from the heterogenous response of individuals to disease which is also reflected in the inter-individual variability of gene expression responses. This in turn obscures differential gene expression analysis (DGE). In the midst of the COVID-19 pandemic, we wondered whether an alternative to DGE approaches could be applied to dissect the molecular nature of a host-response to infection exemplified here by an analysis of H1N1 influenza, community/hospital acquired pneumonia (CAP) and sepsis. To this end, we turned to the analysis of ensemble gene noise. Ensemble gene noise, as we defined it here, represents a variance within an individual for a collection of genes encoding for either members of known biological pathways or subunits of annotated protein complexes. From the law of total variance, ensemble gene noise depends on the stoichiometry of the ensemble genes expression and on their average noise (variance). Thus, rather than focusing on specific genes, ensemble gene noise allows for the holistic identification and interpretation of gene expression disbalance on the level of gene networks and systems. Comparing H1N1, CAP and sepsis patients we spotted common disturbances in a number of pathways/protein complexes relevant to the sepsis pathology which lead to an increase in the ensemble gene noise. Among others, these include mitochondrial respiratory chain complex I and peroxisomes which could be readily targeted for adjuvant treatment by methylene blue and 4-phenylbutyrate respectively. Finally, we showed that ensemble gene noise could be successfully applied for the prediction of clinical outcome, namely mortality, of CAP and sepsis patients. Thus, we conclude that ensemble gene noise represents a promising approach for the investigation of molecular mechanisms of a pathology through a prism of alterations in coherent expression of gene circuits.

bioinformatics↗