Publications by authors named "Karthik A Jagadeesh"

Both common and rare genetic variants influence complex traits and common diseases. Genome-wide association studies have identified thousands of common-variant associations, and more recently, large-scale exome sequencing studies have identified rare-variant associations in hundreds of genes. However, rare-variant genetic architecture is not well characterized, and the relationship between common-variant and rare-variant architecture is unclear.

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  • - We studied 1,130 E3 ligases and their roles in the inflammatory response of primary dendritic cells using Perturb-seq, revealing their significant impact on different types of dendritic cells and macrophages.
  • - E3 ligases and their adaptors work together but interact with different substrate recognition adaptors, influencing various processes in dendritic cell development and function.
  • - A deep learning model named comβVAE was developed to predict outcomes of new E3 ligase combinations, showing that the E3 regulatory network is linked to genetic variations and abnormal gene expression in immune-related human diseases.
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Pancreatic ductal adenocarcinoma (PDAC) is one of the most treatment refractory and lethal malignancies. The diversity of endothelial cell (EC) lineages in the tumor microenvironment (TME) impacts the efficacy of antineoplastic therapies, which in turn remodel EC states and distributions. Here, we present a single-cell resolution framework of diverse EC lineages in the PDAC TME in the context of neoadjuvant chemotherapy, radiotherapy, and losartan.

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  • Genome-wide association studies help identify genes linked to diseases, but the specific cell types involved are often unclear.
  • The study introduces sc-linker, a framework that combines single-cell RNA-sequencing data and genetic information to uncover how genes impact diseases through particular cell types.
  • Findings revealed important connections between specific cell types and diseases, such as certain neurons in depression and immune cell programs in autoimmune diseases, shedding light on potential therapeutic targets.
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Several biobanks, including UK Biobank (UKBB), are generating large-scale sequencing data. An existing method, SAIGE-GENE, performs well when testing variants with minor allele frequency (MAF) ≤ 1%, but inflation is observed in variance component set-based tests when restricting to variants with MAF ≤ 0.1% or 0.

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  • Single-cell RNA sequencing (scRNA-seq) has been enhanced by a new method called single-cell disease relevance score (scDRS), which connects genetic risk for diseases to individual cells without needing predefined cell types.
  • scDRS was tested on 74 diseases using 1.3 million single-cell profiles from various tissues, with results confirming existing cell-type-disease links while also revealing new subpopulations tied to specific diseases.
  • The analysis showed that genes linked to the scDRS score are significantly associated with important drug targets and genetic diseases, suggesting that this technique could help in drug development and understanding disease mechanisms.
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  • Pancreatic ductal adenocarcinoma (PDAC) is a deadly cancer with limited treatment options, and current methods for understanding its molecular characteristics are inadequate.
  • Researchers used advanced techniques, including single-nucleus RNA sequencing and digital spatial profiling, to analyze 43 PDAC tumors, revealing key cellular subtypes and their interactions.
  • They identified new malignant cell programs linked to poor outcomes and established three distinct multicellular communities, providing insights that could improve patient stratification in clinical trials and guide targeted therapies.
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  • - Disease-associated SNPs are mainly regulatory and often do not point directly to target genes, complicating the understanding of their effects on diseases.
  • - The researchers developed a heritability-based combined S2G strategy (cS2G) that merges results from seven different linking strategies, achieving better performance in predicting gene associations with common diseases compared to individual methods.
  • - The cS2G approach was applied to data from the UK Biobank to predict over 5,000 causal SNP-gene-disease connections and found that a small percentage of genes accounted for a significant portion of the SNP-related heritability across diseases.
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Genome-wide association studies (GWAS) provide a powerful means to identify loci and genes contributing to disease, but in many cases the related cell types/states through which genes confer disease risk remain unknown. Deciphering such relationships is important for identifying pathogenic processes and developing therapeutics. Here, we introduce sc-linker, a framework for integrating single-cell RNA-seq (scRNA-seq), epigenomic maps and GWAS summary statistics to infer the underlying cell types and processes by which genetic variants influence disease.

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  • This study examines the pathophysiology of COVID-19 by analyzing single-cell and spatial atlases from various organ autopsy samples of individuals who died from the virus.
  • Findings revealed significant changes in lung tissue, including impaired tissue regeneration and inflammation, indicating how SARS-CoV-2 affects different cell types.
  • The research provides crucial insights into the biological impact of severe COVID-19, aiding in the development of potential new treatments.
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DNA profiling has become an essential tool for crime solving and prevention, and CODIS (Combined DNA Index System) criminal investigation databases have flourished at the national, state and even local level. However, reports suggest that the DNA profiles of all suspects searched in these databases are often retained, which could result in racial profiling. Here, we devise an approach to both enable broad DNA profile searches and preserve exonerated citizens' privacy through a real-time privacy-preserving procedure to query CODIS databases.

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  • The SARS-CoV-2 pandemic has led to over 1 million deaths worldwide, primarily due to severe lung injuries and multiple organ failures, but there is limited understanding of the immune responses involved in COVID-19.
  • Researchers collected and analyzed over 420 tissue samples from various organs of 17 COVID-19 victims, utilizing advanced techniques like RNA sequencing to map out cellular changes related to their illness.
  • Significant findings include alterations in lung tissue cell types, such as the increase of specific progenitor cells and myofibroblasts, indicating impaired tissue repair and failed regenerative processes in severely damaged lungs.
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Angiotensin-converting enzyme 2 (ACE2) and accessory proteases (TMPRSS2 and CTSL) are needed for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) cellular entry, and their expression may shed light on viral tropism and impact across the body. We assessed the cell-type-specific expression of ACE2, TMPRSS2 and CTSL across 107 single-cell RNA-sequencing studies from different tissues. ACE2, TMPRSS2 and CTSL are coexpressed in specific subsets of respiratory epithelial cells in the nasal passages, airways and alveoli, and in cells from other organs associated with coronavirus disease 2019 (COVID-19) transmission or pathology.

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The diagnosis of Mendelian disorders requires labor-intensive literature research. Trained clinicians can spend hours looking for the right publication(s) supporting a single gene that best explains a patient's disease. AMELIE (Automatic Mendelian Literature Evaluation) greatly accelerates this process.

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Purpose: Both monogenic pathogenic variant cataloging and clinical patient diagnosis start with variant-level evidence retrieval followed by expert evidence integration in search of diagnostic variants and genes. Here, we try to accelerate pathogenic variant evidence retrieval by an automatic approach.

Methods: Automatic VAriant evidence DAtabase (AVADA) is a novel machine learning tool that uses natural language processing to automatically identify pathogenic genetic variant evidence in full-text primary literature about monogenic disease and convert it to genomic coordinates.

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Human neural stem cells (NSCs) offer therapeutic potential for neurodegenerative diseases, such as inherited monogenic nervous system disorders, and neural injuries. Gene editing in NSCs (GE-NSCs) could enhance their therapeutic potential. We show that NSCs are amenable to gene targeting at multiple loci using Cas9 mRNA with synthetic chemically modified guide RNAs along with DNA donor templates.

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Exome analysis of patients with a likely monogenic disease does not identify a causal variant in over half of cases. Splice-disrupting mutations make up the second largest class of known disease-causing mutations. Each individual (singleton) exome harbors over 500 rare variants of unknown significance (VUS) in the splicing region.

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  • - The human genome contains about 2% of protein-coding genes, but most disease-causing variants are found in exons or splice sites, making it essential to look beyond coding regions for causes of certain disorders.
  • - A case study of an Afghan male with Wilson Disease showed he had no harmful variants in the known causative gene ATP7B, yet examination revealed a variant in the ATP7B promoter that disrupts a site crucial for gene regulation.
  • - This discovery highlights the importance of investigating non-coding genetic variants and suggests that similar methods could be used to identify other non-coding variants linked to diseases. !*
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Purpose: Exome sequencing and diagnosis is beginning to spread across the medical establishment. The most time-consuming part of genome-based diagnosis is the manual step of matching the potentially long list of patient candidate genes to patient phenotypes to identify the causative disease.

Methods: We introduce Phrank (for phenotype ranking), an information theory-inspired method that utilizes a Bayesian network to prioritize candidate diseases or genes, as a stand-alone module that can be run with any underlying knowledgebase and any variant filtering scheme.

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Robinow syndrome (RS) is a well-recognized Mendelian disorder known to demonstrate both autosomal dominant and autosomal recessive inheritance. Typical manifestations include short stature, characteristic facies, and skeletal anomalies. Recessive inheritance has been associated with mutations in ROR2 while dominant inheritance has been observed for mutations in WNT5A, DVL1, and DVL3.

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Patient genomes are interpretable only in the context of other genomes; however, genome sharing enables discrimination. Thousands of monogenic diseases have yielded definitive genomic diagnoses and potential gene therapy targets. Here we show how to provide such diagnoses while preserving participant privacy through the use of secure multiparty computation.

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Variant pathogenicity classifiers such as SIFT, PolyPhen-2, CADD, and MetaLR assist in interpretation of the hundreds of rare, missense variants in the typical patient genome by deprioritizing some variants as likely benign. These widely used methods misclassify 26 to 38% of known pathogenic mutations, which could lead to missed diagnoses if the classifiers are trusted as definitive in a clinical setting. We developed M-CAP, a clinical pathogenicity classifier that outperforms existing methods at all thresholds and correctly dismisses 60% of rare, missense variants of uncertain significance in a typical genome at 95% sensitivity.

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