Добавил:
kiopkiopkiop18@yandex.ru t.me/Prokururor I Вовсе не секретарь, но почту проверяю Опубликованный материал нарушает ваши авторские права? Сообщите нам.
Вуз: Предмет: Файл:

Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_5529_Библиотеки_им_академика_М_И_Перельмана

.pdf
Скачиваний:
0
Добавлен:
31.08.2026
Размер:
26 Мб
Скачать
194 Bioinformatics of Autoimmune Diseases
FIGURE 5.6 RNA-Seq gene expression of GeneX: Positive versus negative anti-CCP.
molecular functions that are overrepresented. Rather than analyzing genes in isolation, functional enrichment looks for statistically signicant associations between input gene sets and annotated databases such as Gene Ontology (GO), KEGG pathways, and Reactome. These databases group genes based on shared biological processes, molecular functions, or cellular components, enabling researchers to understand the broader biological context of their ndings.
The analysis typically begins with a list of genes that are signicantly upregulated or downregu­lated in a condition of interest. Functional enrichment tools, such as g:Profiler, use statistical models to determine whether certain pathways or functions appear more frequently in the input list than would be expected by chance. These enriched terms can highlight common mechanisms shared among the genes, such as immune signaling, cytokine activity, apoptosis, or cell cycle regu­lation. The output helps to prioritize pathways for further investigation and can provide mechanistic insights that are not immediately apparent from the gene-level data alone.
In the context of autoimmune diseases, functional enrichment is particularly valuable because these conditions often involve complex and dysregulated immune pathways. Diseases such as rheu­matoid arthritis, lupus, or MS involve numerous genes that act together within signaling cascades, inammatory responses, or immune cell activation. Functional enrichment can reveal that differen­tially expressed genes in patient samples converge on pathways such as TNF signaling, interferon responses, or antigen processing. This not only enhances the understanding of disease mechanisms but also supports the identication of potential biomarkers or therapeutic targets. Furthermore, since autoimmune diseases may affect diverse tissues and cell types, enrichment analysis allows researchers to lter and interpret gene expression data through a systems biology lens, helping to make sense of the molecular heterogeneity that characterizes these conditions.
The run _ enrichment.py program is a standalone script designed to perform functional enrichment analysis using the g:Profile r A PI. It takes as input a le containing a list of gene symbols, typically generated from RNA-Seq differential expression analysis, and submits this list to the g:P rofile r service to identify overrepresented biological functions, pathways, or molecular annotations. The script is exible and designed to work with gene lists formatted as CSV or plain
195 RNA Sequencing
text les, where the genes are typically listed in the rst column. It supports enrichment across a range of biological sources, including Gene Ontology (GO), KEGG, and Reactome, and is set to query the human genome by default.
Upon execution, the script validates that the gene list is non-empty and proceeds to prepare a structured query for g:Proler’s REST API. It submits the gene list and receives a response contain­ing any enriched terms along with relevant metadata such as p-values, term size, and the number of overlapping genes. These results are parsed and saved in CSV format to a designated output le, making them easy to review or incorporate into downstream analyses. The script also provides summary feedback in the terminal, including the number of genes queried and a preview of the top enriched terms grouped by source. This helps users to quickly assess whether any meaningful biological patterns were detected.
The expected output from run_enrichment.py is a structured CSV le listing enriched pathways or functional terms, each accompanied by their associated p-value, term size, and intersection size. This output enables researchers to understand which biological processes or molecular mechanisms are most prominently represented among their genes of interest. In practice, this helps translate sta­tistical gene-level results into interpretable biological insights. For example, an analysis involving genes upregulated in rheumatoid arthritis might reveal enrichment in pathways such as cytokine signaling, interferon response, or antigen presentation, pointing to dysregulated immune activity at the systems level. The script’s design ensures that such insights are easily accessible and formatted in a way that is compatible with visualization tools or further statistical summarization.
Table 5.7 is a sample table that represents what the output of the run _ enrichment.py
script might look like after querying g:P rofile r with a list of human gene symbols. The table reects enriched terms from different biological databases, along with relevant statistical and bio­logical metadata.
Each row represents an enriched term, including the biological source (GO:BP for Biological Process, GO:MF for Molecular Function, KEGG, or Reactome), the term name, the associated p-value indicating statistical signicance, the total number of genes annotated to that term (term_ size), and how many of those genes were present in the input gene list (intersection_size).
This table helps the researcher interpret which biological themes are most relevant to the gene list being studied, making it a key component in translating raw RNA-Seq data into meaningful insights about cellular pathways or disease mechanisms.
For example, the rst row in the enrichment table indicates that the biological process “response to interferon-gamma” is signicantly overrepresented in the list of genes. Out of all the genes known to be involved in this process, which number 65 in the background set, 7 were found among the
TABLE 5.7 Functional Enrichment of RNA-Seq Top Expressed Genes
Source Name p-Value Term Size Intersection Size
GO:BP Response to interferon-gamma 0.000021 65 7 GO:BP Regulation of cytokine production 0.000134 120 9 GO:MF Chemokine receptor binding 0.000215 20 4 KEGG TNF signaling pathway 0.000742 95 6 REAC Interferon signaling 0.001102 88 5 GO:BP Leukocyte migration 0.0034 142 6 GO:MF Cytokine activity 0.004501 35 4 REAC Antigen processing and presentation 0.00911 53 3 GO:MF Nicotinamide-nucleotide adenylyltransferase activity 0.014936 3 2 GO:MF Protein ADP-ribosyltransferase-substrate adaptor activity 0.029815 4 2
196 Bioinformatics of Autoimmune Diseases
genes we submitted for enrichment analysis. The associated adjusted p-value is 0.000021, showing a very strong statistical signicance after correcting for multiple testing.
This result suggests that our gene set is highly involved in the cellular response to interferon­gamma, a cytokine that plays a central role in immune activation. Interferon-gamma is particularly important in the regulation of immune responses, especially in the context of inammation and host defense mechanisms. The enrichment of this term implies that the underlying biological condition we are studying may involve heightened interferon-gamma signaling.
Given that our RNA-Seq data is related to an autoimmune disease such as rheumatoid arthri­tis, this nding is biologically meaningful. Interferon-gamma has been implicated in autoimmune pathogenesis, where it can contribute to the activation of macrophages, upregulation of antigen pre­sentation, and the promotion of inammatory pathways. The presence of this enrichment strength­ens the interpretation that immune system dysregulation, particularly through interferon-gamma signaling, is a prominent feature in your dataset.
5.6 SMALL RNA DATA ANALYSIS
Small RNAs are a diverse class of non-coding RNAs, typically ranging in length from 18 to 30nucleotides, that play essential roles in regulating gene expression at both transcriptional and post-transcriptional levels. The most studied types include microRNAs (miRNAs), small interfering RNAs (siRNAs), and PIWI-interacting RNAs (piRNAs). Among these, miRNAs are particularly signicant in the context of human diseases, including autoimmune disorders. As illustrated in
Figure 5.7, the miRNA pathway begins with the transcription of a gene encoding a primary miRNA
(pri-miRNA). The nuclear enzyme Drosha processes the pri-miRNA into a precursor miRNA (pre-miRNA), which is then exported to the cytoplasm. There, the enzyme Dicer further cleaves the pre-miRNA into a mature miRNA duplex. One strand of this duplex is incorporated into the miRNA-induced silencing complex (miRISC). The mature miRNA guides the complex to target mRNAs through base pairing. Perfect complementarity typically results in mRNA degradation, while partial complementarity leads to translational repression.
In the immune system, miRNAs are critical regulators of immune cell development and func­tion. For example, specic miRNAs control the differentiation of T and B lymphocytes, the acti­vation of dendritic cells, and the production of cytokines. Dysregulation of these miRNAs can
FIGURE 5.7 M icroRNA pathway.
197 RNA Sequencing
disturb immune homeostasis, potentially leading to autoimmunity. In autoimmune diseases, aber­rant expression proles of miRNAs have been consistently observed. Certain miRNAs are over­expressed and act as pro-inammatory agents, enhancing the activation of immune cells and the production of inammatory cytokines. Others are under-expressed, leading to a failure in suppress­ing inappropriate immune responses. These changes contribute to the breakdown of self-tolerance and the development of chronic inammation characteristic of autoimmune conditions.
Emerging evidence suggests that miRNAs may also serve as biomarkers for diagnosis and prog­nosis in autoimmune diseases. For instance, altered levels of circulating miRNAs in patient plasma or serum can reect disease activity and therapeutic response, offering a non-invasive tool for moni­toring disease progression. Additionally, specic miRNAs have been shown to correlate with the severity of joint damage in rheumatoid arthritis or the presence of autoantibodies in lupus. Their stability in body uids and sensitivity to pathological changes make them attractive candidates for early detection and personalized treatment strategies.
From a therapeutic perspective, modulating miRNA expression is an exciting frontier. Strategies such as miRNA mimics to restore downregulated miRNAs, or antagomirs to inhibit overexpressed ones, are being explored in preclinical and clinical studies. However, challenges remain in ensur­ing the specicity, delivery, and safety of such approaches. Nonetheless, the ability of small RNAs to inuence key pathways in immune regulation offers a promising avenue for developing targeted therapies in autoimmune diseases, potentially shifting the paradigm from broad immunosuppres­sion to precision medicine.
5.6.1 SMALL RNA DIFFERENTIAL ANALYSIS
The above-discussed RNA-Seq pipelines were designed for standard transcriptome analysis, pri­marily focusing on mRNA. To adapt this pipeline for small RNA-Seq, several critical modica­tions can be implemented to accommodate the unique properties of small RNA molecules such as miRNAs, piRNAs, and other non-coding RNA species. Unlike mRNAs, which are typically hundreds to thousands of nucleotides in length and often spliced, small RNAs are short (18–30 nt) and unspliced. This necessitates changes in read processing, alignment strategies, and expression quantication methods.
One of the primary changes involved customizing the read trimming step. While mRNA pipe­lines often use fastp or Trimmomatic with generic adapter trimming, small RNA libraries require precise removal of 3 adapter sequences due to the short length of the reads. These adapters, if not removed accurately, can dominate the sequence and interfere with mapping. The pipeline therefore retains fastp but incorporates specic adapter sequences commonly used in small RNA library preparation, ensuring only high-quality and adapter-free reads are passed to the alignment step.
The alignment phase shifts from STAR, a spliced aligner optimized for long reads, to Bowtie1, which is tailored for short, unspliced sequences and allows for strict mismatch control. This is essential because small RNAs require exact or near-exact matches to reference sequences due to their short length; even a single mismatch can signicantly reduce mapping accuracy. The refer­ence genome used for alignment can be replaced or augmented with a specialized index, such as one built from miRbase (publicly accessible online database), depending on the small RNA species under study.
Gene-level quantication with tools like featureCounts, which rely on GTF annotations, is not suitable for small RNA. Instead, the pipeline performs sequence-based quantication by count­ing the frequency of each unique sequence mapped in the BAM les. This approach is critical for detecting small RNA expression since many small RNAs do not correspond to annotated genes, and their regulatory effects are sequence-specic rather than gene-specic. The sequence-level count matrix is then normalized using CPM, and genes with low expression across samples are ltered out to reduce noise and false positives in downstream analysis.
198 Bioinformatics of Autoimmune Diseases
Differential expression analysis remains similar in concept but is applied to unique sequences rather than annotated gene IDs. In srna _ pipeline _ ttest.py, statistical comparisons are performed using t-tests between biological groups, followed by p-value adjustment using the Benjamini-Hochberg method to control for false discovery rate. The interpretation of the results, however, focuses on identifying differentially expressed small RNA sequences that may correspond to functionally important non-coding RNAs, such as miRNAs that are known to regulate gene expression post-transcriptionally.
In srna _ pipeline _ 1wayA nova.py, the differential _ expression function was modied to accommodate the characteristics of small RNA-Seq data and support one-way ANOVA across multiple biological groups. Instead of comparing two groups using a t-test as in standard RNA-Seq analysis, the updated function performs an ANOVA test to evaluate expres­sion differences among more than two groups dened by a metadata column, such as ethnicity. This is essential in studies with more complex experimental designs. Additionally, the function was adapted to operate on unique small RNA sequences rather than gene identiers, reecting the sequence-centric nature of small RNA data. To aid in biological interpretation, log2 fold changes are calculated between either the top two most expressed groups or relative to a specied control group. The function returns a ranked table of sequences with raw and adjusted p-values, allowing for identication of differentially expressed small RNAs across diverse sample categories.
In srna _ pipeline _ 1wAnova _ ctrl.py, the differential _ expression func- tion was modied to analyze small RNA expression at the sequence level across multiple groups using one-way ANOVA, while also incorporating log2 fold change calculations. Instead of operat­ing on annotated gene symbols, the function now uses unique small RNA sequences as identiers, which is more appropriate given that many small RNAs do not correspond to known gene annota­tions. For each sequence, expression values are grouped by a metadata column such as ethnicity, and ANOVA is used to detect overall differences across the groups. If a control group is specied, the function computes log2 fold changes comparing each other group to the control, enabling targeted biological interpretation. If no control is provided, the log2 fold change is calculated between the two groups with the highest mean expression for each sequence. This structure enables ne-grained comparison of small RNA expression patterns across heterogeneous populations while preserving statistical rigor through multiple testing correction.
This modied pipeline reects a tailored approach that respects the biological and technical differences between mRNA and small RNA data. It enhances the accuracy of read processing and quantication, ensuring that the distinct characteristics of small RNAs are appropriately captured, ultimately leading to more biologically meaningful and reproducible results.
5.6.2 VISUALIZING DIFFERENTIAL SMALL RNA EXPRESSION
5.6.2.1 PCA Plot
In the sRNA _plot _pca.py program, the PCA plotting function was modied to suit small RNA-Seq data by shifting the input from gene-level expression proles to sequence-level normal­ized counts, which is more appropriate for small RNA analysis (Figure 5.8). While the overall struc­ture of the PCA computation remains the same (standardizing the data, performing dimensionality reduction with PCA, and visualizing sample clustering) the underlying biological entities are differ­ent. Instead of genes, the principal components now reect variance across short RNA sequences, many of which may correspond to miRNAs, piRNAs, or other non-coding RNAs. This shift affects interpretation: the clusters seen in the PCA plot represent similarities or differences in small RNA expression proles across samples, which could reect biological groupings like treatment or phe­notype, but at the regulatory RNA level rather than transcript abundance. As many small RNAs have precise and targeted regulatory roles, clustering patterns may reveal subtle yet biologically meaningful differences in post-transcriptional regulation that may not be captured by mRNA-level
199 RNA Sequencing
FIGURE 5.8 PCA plot of small RNA (rheumatoid arthritis).
PCA. Thus, while the visualization approach is technically the same, the biological interpretation focuses on regulatory signatures rather than transcriptomic structure.
5.6.2.2 Volcano Plot
In sR N A _ plot _ volc ano.p y, the volcano plot (Figure 5.9) was modied to reect the charac- teristics of small RNA-Seq data by replacing gene-level identiers with sequence-level identiers, typically referred to as “Sequence” in the differential expression output. In standard mRNA-Seq volcano plots, each point represents a gene, often annotated with gene symbols, and the plot high­lights genes with signicant changes in expression between conditions. For small RNA, however, many features of interest are not genes but short RNA sequences such as miRNAs, piRNAs, or other non-coding RNA fragments. The updated plot handles these by labeling and coloring points based on log2 fold change and adjusted p-value, exactly as in the original, but using sequence identi­ers instead of gene symbols.
This change ensures that the volcano plot remains informative and statistically rigorous while being biologically appropriate for small RNA studies. The overall structure of the plot remains the same (log2 fold change on the x-axis and negative log10 adjusted p-value on the y-axis) but the interpretation shifts from gene-level transcriptional regulation to sequence-level insights into regu­latory RNA dynamics. The labeled top sequences are the most statistically signicant small RNAs, and depending on annotation, they could represent miRNAs with known targets or novel regula­tory molecules. This makes the volcano plot a powerful tool not just for identifying differentially expressed RNAs but also for generating hypotheses about post-transcriptional regulation and small RNA-mediated pathways.
200 Bioinformatics of Autoimmune Diseases
FIGURE 5.9 Volcano plot of small RNA (rheumatoid arthritis).
5.6.2.3 MA Plot
In s R NA _ plot _ MA.py, the MA plot (Figure 5.10) was modied to accommodate the charac- teristics of small RNA-Seq data by shifting its focus from gene-level expression to sequence-level expression. In the original mRNA-Seq version, genes were used as identiers and the x-axis rep­resented the average log2 CPM of gene expression, while the y-axis showed the log2 fold change between groups. In the small RNA version, the same structure is preserved, but the identiers are unique small RNA sequences, which may or may not correspond to annotated genes. This change ensures that the plot reects the actual biology of small RNAs, many of which function as indi­vidual regulatory molecules and are not captured in standard gene annotations.
The interpretation of the MA plot in the small RNA context also shifts slightly. In mRNA analysis, differentially expressed genes often indicate changes in transcriptional output or shifts in broader functional pathways. In contrast, differentially expressed small RNAs may suggest changes in regulatory activity, such as miRNA-mediated repression or modulation of post-transcriptional networks. Therefore, while the visual interpretation remains the same (spotting sequences that are highly expressed and differentially regulated) the biological conclusions focus more on gene regulation and interaction networks rather than protein-coding functions. The use of small RNA sequences on the y-axis also means that additional care must be taken when annotating or inter­preting individual points, as these may correspond to miRNAs, piRNAs, or uncharacterized short RNAs with distinct biological roles.
5.6.2.4 Heatmap Plot
In sR NA _ plot _ he atm ap.p y, the heatmap plot (Figure 5.11) was adapted from an mRNA- based format to accommodate small RNA-Seq data by shifting from gene symbols to sequence­level identiers. In the original version, the heatmap displayed normalized expression levels of top differentially expressed genes using gene symbols as row labels. For small RNA-Seq, many features
201 RNA Sequencing
FIGURE 5.10 MA plot of small RNA (rheumatoid arthritis).
FIGURE 5.11 Heatmap plot of small RNA (rheumatoid arthritis).
202 Bioinformatics of Autoimmune Diseases
of interest are short RNA sequences that do not map directly to known genes. The updated version reads a list of top small RNA sequences, lters the normalized expression matrix accordingly, and uses these sequences as the row identiers in the heatmap. The expression values are standardized across samples, and the samples are annotated with group labels from the metadata, allowing for visual clustering of both small RNA expression and sample grouping.
The interpretation also shifts slightly. While an mRNA heatmap often highlights coordinated changes in gene expression related to specic biological pathways or cellular processes, a small RNA heatmap reects changes in post-transcriptional regulation and small RNA-mediated control mechanisms. The rows now represent individual small RNAs (such as miRNAs or other regulatory fragments) which may target multiple genes and inuence gene expression indirectly. Consequently, the heatmap allows researchers to visually assess patterns of regulatory RNA activity across experi­mental groups. This can reveal subtle regulatory shifts that may not be apparent in mRNA pro­les, especially in cases where transcriptional changes are minimal but regulatory mechanisms are actively altered through small RNA expression.
5.7 SUMMARY
This chapter provides a comprehensive overview of RNA sequencing (RNA-Seq) and its critical role in understanding gene expression in autoimmune diseases, with a particular emphasis on rheu­matoid arthritis (RA). It begins by exploring how tightly regulated gene expression governs immune responses and how its dysregulation contributes to autoimmune pathogenesis. The text illustrates how RNA-Seq enables the identication of gene signatures and pathways involved in diseases like SLE, RA, MS, and IBD, offering insights into mechanisms and guiding personalized therapeutic strategies. Examples such as the type I interferon signature in SLE and the synovial expression pro­les in RA underscore the utility of transcriptomic data in clinical contexts.
The chapter transitions into practical applications, detailing how to extract raw sequencing data and associated metadata from public repositories like the NCBI SRA. Using a specic RA study as a case example, it walks through the scripting and methodological process of retrieving and orga­nizing BioProject metadata. Clinical variables such as anti-CCP status, CRP, ESR, pathotype, and joint counts are explained in depth to underscore their biological relevance and role in shaping gene expression patterns.
A signicant portion is devoted to implementing a robust RNA-Seq data analysis pipeline using Python. It outlines every step from preprocessing raw FASTQ les, reference genome indexing, read alignment, and quantication to gene ltering and normalization. The chapter further delves into statistical analyses for differential expression, including t-tests, one-way and two-way ANOVA, and post hoc comparisons using Tukey’s HSD. Each statistical approach is framed with examples tailored to autoimmune disease research, emphasizing the importance of appropriate experimental design and interpretation.
Visualization techniques, such as PCA plots and volcano plots, are introduced as indispensable tools for interpreting differential gene expression results. These methods help to assess clustering, identify signicant genes, and communicate ndings effectively. Finally, the chapter underscores the power of integrating RNA-Seq with clinical and phenotypic metadata to uncover complex gene­environment interactions and supports the advancement of precision medicine in autoimmune diseases. Through a combination of theory, application, and coding practices, the chapter equips readers with a practical and intuitive foundation for RNA-Seq analysis in biomedical research.
BIBLIOGRAPHY
Anders, S., & Huber, W. (2010). Differential expression analysis for sequence count data. Genome Biology,
11(10), R106. https://doi.org/10.1186/gb-2010-11-10-r106
Bolger, A. M., Lohse, M., & Usadel, B. (2014). Trimmomatic: A exible trimmer for Illumina sequence data.
Bioinformatics, 30(15), 2114–2120. https://doi.org/10.1093/bioinformatics/btu170
203 RNA Sequencing
Chen, S., Zhou, Y., Chen, Y., & Gu, J. (2018). fastp: An ultra-fast all-in-one FASTQ preprocessor.
Bioinformatics, 34(17), i884–i890. https://doi.org/10.1093/bioinformatics/bty560
Cunningham, F., Allen, J. E., Allen, J., Alvarez-Jarreta, J., Amode, M. R., Armean, I. M., … Flicek, P. (2022).
Ensembl 2022. Nucleic Acids Research, 50(D1), D988–D995. https://doi.org/10.1093/nar/gkab1049
Dobin, A., Davis, C. A., Schlesinger, F., Drenkow, J., Zaleski, C., Jha, S., … Gingeras, T. R. (2013).
STAR: Ultrafast universal RNA-seq aligner. Bioinformatics, 29(1), 15–21. https://doi.org /10.1093/
bioinformatics/bts635
Frankish, A., Diekhans, M., Ferreira, A. M., Johnson, R., Jungreis, I., Loveland, J., … Flicek, P. (2021).
GENCODE reference annotation for the human and mouse genomes. Nucleic Acids Research, 49(D1), D916–D923. https://doi.org /10.1093/nar/gkaa1087
Fransen, J., & van Riel, P. L. C. M. (2009). The Disease Activity Score and the EULAR response criteria.
Rheumatic Disease Clinics of North America, 35(4), 745–757. https://doi.org/10.1016/j.rdc.2009.10.001
Heinz, S., Benner, C., Spann, N., Bertolino, E., Lin, Y. C., Laslo, P., … Glass, C. K. (2010). Simple combina-
tions of lineage-determining transcription factors prime cis-regulatory elements required for macro­phage and B cell identities. Molecular Cell, 38(4), 576–589. https://doi.org/10.1016/j.molcel.2010.05.004
Ismail, H. D. (2022). Bioinformatics: A practical guide to NCBI databases and sequence alignments (1st ed.).
Chapman and Hall/CRC. https://doi.org/10.1201/9781003226611
Ismail, H. D. (2023). Bioinformatics: A practical guide to next generation sequencing data analysis (1st ed.).
Chapman and Hall/CRC. https://doi.org/10.1201/9781003355205
Liao, Y., Smyth, G. K., & Shi, W. (2014). featureCounts: An efcient general purpose program for assign-
ing sequence reads to genomic features. Bioinformatics, 30(7), 923–930. https://doi.org/10.1093/
bioinformatics/btt656
Love, M. I., Huber, W., & Anders, S. (2014). Moderated estimation of fold change and dispersion for RNA-seq
data with DESeq2. Genome Biology, 15(12), 550. ht tps://do i.org /10.1186/s130 59- 014- 0550-8
McKinney, W. (2010). Data structures for statistical computing in Python. Proceedings of the 9th Python in
Science Conference, 51–56. https://doi.org/10.25080/Majora-92bf1922-00a
National Center for Biotechnology Information. (2022). BioProject PRJEB52174: RNA-seq of synovial biop-
sies from early rheumatoid arthritis patients before and after treatment [Data set]. NCBI Sequence Read Archive. https://www.ncbi.nlm.nih.gov/bioproject/PRJEB52174
NCBI Resource Coordinators. (2018). Database resources of the National Center for Biotechnology
Information. Nucleic Acids Research, 46(D1), D8–D13. https://doi.org/10.1093/nar/gkx1095
Prevoo, M. L. L., van ’t Hof, M. A., Kuper, H. H., van Leeuwen, M. A., van de Putte, L. B. A., & van Riel,
P.L. C. M. (1995). Modied disease activity scores that include twenty-eight-joint counts: Development and validation in a prospective longitudinal study of patients with rheumatoid arthritis. Arthritis & Rheumatism, 38(1), 44–48. https://doi.org/10.1002/art.1780380107
Robinson, M. D., McCarthy, D. J., & Smyth, G. K. (2010). edgeR: A Bioconductor package for differen-
tial expression analysis of digital gene expression data. Bioinformatics, 26(1), 139–140. https://doi.
org/10.1093/bioinformatics/ btp616
Subramanian, A., Tamayo, P., Mootha, V. K., Mukherjee, S., Ebert, B. L., Gillette, M. A., … Mesirov,
J. P. (2005). Gene set enrichment analysis: A knowledge-based approach for interpreting genome-wide expression proles. Proceedings of the National Academy of Sciences, 102(43), 15545–15550. https://
doi.org /10.1073/pnas.0506580102
Trapnell, C., Williams, B. A., Pertea, G., Mortazavi, A., Kwan, G., van Baren, M. J., … Pachter, L. (2010).
Transcript assembly and quantication by RNA-Seq reveals unannotated transcripts and isoform switch­ing during cell differentiation. Nature Biotechnology, 28(5), 511–515. https://doi.org/10.1038/nbt.1621
Wang, Z., Gerstein, M., & Snyder, M. (2009). RNA-Seq: A revolutionary tool for transcriptomics. Nature
Reviews Genetics, 10(1), 57–63. https://doi.org/10.1038/nrg2484
Zhang, B., Gaiteri, C., Bodea, L. G., Wang, Z., McElwee, J., Podtelezhnikov, A. A., … Emilsson, V. (2013).
Integrated systems approach identies genetic nodes and networks in late-onset Alzheimer’s disease. Cell, 153(3), 707–720. https://doi.org/10.1016/j.cell.2013.03.030
Zhang, Y., Parmigiani, G., & Johnson, W. E. (2020). ComBat-seq: Batch effect adjustment for RNA-seq count
data. NAR Genomics and Bioinformatics, 2(3), lqaa078. https://doi.org/10.1093/nargab/lqaa078