scholarly journals Estimating the rate of cell type degeneration from epigenetic sequencing of cell-free DNA

2020 ◽  
Author(s):  
Christa Caggiano ◽  
Barbara Celona ◽  
Fleur Garton ◽  
Joel Mefford ◽  
Brian Black ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Pregnant Women ◽  
Reference Data ◽  
Cell Types ◽  
The Body ◽  
Cell Type ◽  
Cell Free Dna ◽  
Free Dna ◽  
Als Patients ◽  
Low Coverage

AbstractCirculating cell-free DNA (cfDNA) in the bloodstream originates from dying cells and is a promising non-invasive biomarker for cell death. Here, we develop a method to accurately estimate the relative abundances of cell types contributing to cfDNA. We leverage the distinct DNA methylation profile of each cell type throughout the body. Decomposing the cfDNA mixture is difficult, as fragments from relevant cell types may only be present in a small amount. We propose an algorithm, CelFiE, that estimates cell type proportion from both whole genome cfDNA input and reference data. CelFiE accommodates low coverage data, does not rely on CpG site curation, and estimates contributions from multiple unknown cell types that are not available in reference data. In simulations we show that CelFiE can accurately estimate known and unknown cell type of origin of cfDNA mixtures in low coverage and noisy data. Simulations also demonstrate that we can effectively estimate cfDNA originating from rare cell types composing less than 0.01% of the total cfDNA. To validate CelFiE, we use a positive control: cfDNA extracted from pregnant and non-pregnant women. CelFiE estimates a large placenta component specifically in pregnant women (p = 9.1 × 10−5). Finally, we use CelFiE to decompose cfDNA from ALS patients and age matched controls. We find increased cfDNA concentrations in ALS patients (p = 3.0 × 10−3). Specifically, CelFiE estimates increased skeletal muscle component in the cfDNA of ALS patients (p = 2.6 × 10−3), which is consistent with muscle impairment characterizing ALS. Quantification of skeletal muscle death in ALS is novel, and overall suggests that CelFiE may be a useful tool for biomarker discovery and monitoring of disease progression.

scholarly journals Comprehensive cell type decomposition of circulating cell-free DNA with CelFiE

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Christa Caggiano ◽  
Barbara Celona ◽  
Fleur Garton ◽  
Joel Mefford ◽  
Brian L. Black ◽  
...  
Keyword(s):  
Biomarker Discovery ◽  
Cell Types ◽  
Cell Type ◽  
Cell Free Dna ◽  
Free Dna ◽  
Noninvasive Biomarker ◽  
Dying Cells ◽  
Als Patients ◽  
Low Coverage ◽  
Circulating Cell Free Dna

AbstractCirculating cell-free DNA (cfDNA) in the bloodstream originates from dying cells and is a promising noninvasive biomarker for cell death. Here, we propose an algorithm, CelFiE, to accurately estimate the relative abundances of cell types and tissues contributing to cfDNA from epigenetic cfDNA sequencing. In contrast to previous work, CelFiE accommodates low coverage data, does not require CpG site curation, and estimates contributions from multiple unknown cell types that are not available in external reference data. In simulations, CelFiE accurately estimates known and unknown cell type proportions from low coverage and noisy cfDNA mixtures, including from cell types composing less than 1% of the total mixture. When used in two clinically-relevant situations, CelFiE correctly estimates a large placenta component in pregnant women, and an elevated skeletal muscle component in amyotrophic lateral sclerosis (ALS) patients, consistent with the occurrence of muscle wasting typical in these patients. Together, these results show how CelFiE could be a useful tool for biomarker discovery and monitoring the progression of degenerative disease.

scholarly journals Comprehensive human cell-type methylation atlas reveals origins of circulating cell-free DNA in health and disease

2018 ◽  
Author(s):  
Joshua Moss ◽  
Judith Magenheim ◽  
Daniel Neiman ◽  
Hai Zemmour ◽  
Netanel Loyfer ◽  
...  
Keyword(s):  
Vascular Endothelial Cells ◽  
White Blood Cells ◽  
Cell Types ◽  
Clinical Findings ◽  
The Body ◽  
Unknown Primary ◽  
Cell Free Dna ◽  
Free Dna ◽  
Circulating Cell Free Dna

AbstractMethylation patterns of circulating cell-free DNA (cfDNA) contain rich information about recent cell death events in the body. Here, we present an approach for unbiased determination of the tissue origins of cfDNA, using a reference methylation atlas of 25 human tissues and cell types. The method is validated usingin silicosimulations as well asin vitromixes of DNA from different tissue sources at known proportions. We show that plasma cfDNA of healthy donors originates from white blood cells (55%), erythrocyte progenitors (30%), vascular endothelial cells (10%) and hepatocytes (1%). Deconvolution of cfDNA from patients reveals tissue contributions that agree with clinical findings in sepsis, islet transplantation, cancer of the colon, lung, breast and prostate, and cancer of unknown primary. We propose a procedure which can be easily adapted to study the cellular contributors to cfDNA in many settings, opening a broad window into healthy and pathologic human tissue dynamics.

scholarly journals Physical activity specifically evokes release of cell-free DNA from granulocytes thereby affecting liquid biopsy

2021 ◽  
Author(s):  
Elmo WI Neuberger ◽  
Stephanie Sontag ◽  
Alexandra Brahmer ◽  
Keito F.A. Philippi ◽  
Markus P. Radsak ◽  
...  
Keyword(s):  
Liquid Biopsy ◽  
Hematological Malignancies ◽  
Cell Types ◽  
Immune Homeostasis ◽  
Cell Type ◽  
Cell Free Dna ◽  
Free Dna ◽  
Myeloid Neoplasms ◽  
Cell Type Specific ◽  
Exercise Induced

Cell-free DNA (cfDNA) methylation-based diagnostics is a promising approach in oncology and hematooncology. Exercise impacts immune homeostasis and leads to a rapid and marked increase of cfDNA levels in blood. Since the origin of cfDNA during exercise remains elusive, the implications for liquid biopsy are unknown. In this study, we identified the source of cfDNA in 10 healthy untrained individuals before, immediately after, and 30 min after exercise, and in 6 patients with myeloid neoplasms or acute leukemia under resting conditions. A pyrosequencing assay was used to analyze the methylation levels of four CpGs, representing DNA from granulocytes, lymphocytes, monocytes, and non-hematopoietic cells. After exercise, cfDNA was almost exclusively released from granulocytes, with cell type specific proportions increasing significantly from 54.1% to 90.2%. Exercise did not trigger the release of cfDNA from lymphocytes or other analyzed cell types, whereas a small amount of cfDNA was released from monocytes. Compared to healthy people, patients with hematological malignancies show significantly higher cfDNA levels at rest with 48.1 (19.1; 78) vs. 8.5 (8.2; 9.5) ng/ml, data expressed as median (25th; 75th percentiles), and considerably higher levels of lymphocyte specific hypomethylated cg17587997 (P<.001). Hence, exercise-induced cfDNA elevations can compromise diagnostic accuracy.

Modeling cell-free DNA fragment size densities for non-invasive detection of cancer.

2021 ◽  
Vol 39 (15_suppl) ◽  
pp. 3058-3058
Author(s):  
Jacob Carey ◽  
Bryan Chesnick ◽  
Denise Butler ◽  
Michael Rongione ◽  
Giovanni Parmigiani ◽  
...  
Keyword(s):  
Fragment Size ◽  
Length Distribution ◽  
Mixture Component ◽  
Base Pairs ◽  
Machine Model ◽  
Cell Free Dna ◽  
Non Invasive ◽  
Free Dna ◽  
Genome Wide ◽  
Low Coverage

3058 Background: Circulating cell-free DNA (cfDNA) is largely nucleosomal in origin with typical fragment lengths of 167 base-pairs reflecting the length of DNA wrapped around-the histone and H1 linker. Given the nucleosomal origin of cfDNA, we have previously used low coverage whole genome sequencing to evaluate DNA fragmentation profiles to sensitively and specifically detect tumor-derived DNA with altered fragment lengths or coverage. Methods: Here we evaluate the use of Bayesian finite mixtures to model the fragment length distribution and demonstrate how the parameters from these models can be useful to distinguish between individuals with and without cancer. We examined the number of cfDNA fragments by size ranging from 100-220bp and approximated the mixture component location, scale, and weight using Markov Chain Monte Carlo. The performance of the method was determined using a ten-fold, ten repeat cross-validation of Gradient Boosted Machine model using 1) our previously described genome-wide fragmentation profile approach, 2) the parameters from the mixture model and 3) a combination of approaches 1) and 2) as features. Results: In this study of 215 cancer patients and 208 cancer-free individuals, we observed cross-validated AUCs of 1) 0.94, 2) 0.95, and 3) 0.97 among the three approaches. Conclusions: Our findings indicate that parsimonious mixture models may improve detection of cancer in conjunction with fragmentation profile analyses across the genome.

scholarly journals Numerous uncharacterized and highly divergent microbes which colonize humans are revealed by circulating cell-free DNA

2017 ◽  
Vol 114 (36) ◽  
pp. 9623-9628 ◽  
Author(s):  
Mark Kowarsky ◽  
Joan Camunas-Soler ◽  
Michael Kertesz ◽  
Iwijn De Vlaminck ◽  
Winston Koh ◽  
...  
Keyword(s):  
Human Body ◽  
Sequence Data ◽  
Human Microbiome ◽  
Pcr Amplification ◽  
The Body ◽  
Direct Pcr ◽  
Cell Free Dna ◽  
Free Dna ◽  
Novel Taxa ◽  
Circulating Cell Free Dna

Blood circulates throughout the human body and contains molecules drawn from virtually every tissue, including the microbes and viruses which colonize the body. Through massive shotgun sequencing of circulating cell-free DNA from the blood, we identified hundreds of new bacteria and viruses which represent previously unidentified members of the human microbiome. Analyzing cumulative sequence data from 1,351 blood samples collected from 188 patients enabled us to assemble 7,190 contiguous regions (contigs) larger than 1 kbp, of which 3,761 are novel with little or no sequence homology in any existing databases. The vast majority of these novel contigs possess coding sequences, and we have validated their existence both by finding their presence in independent experiments and by performing direct PCR amplification. When their nearest neighbors are located in the tree of life, many of the organisms represent entirely novel taxa, showing that microbial diversity within the human body is substantially broader than previously appreciated.

scholarly journals Th2 Cytokine Modulates Herpesvirus Reactivation in a Cell Type Specific Manner

2021 ◽  
Author(s):  
Guoxun Wang ◽  
Christina Zarek ◽  
Tyron Chang ◽  
Lili Tao ◽  
Alexandria Lowe ◽  
...  
Keyword(s):  
B Cells ◽  
Cell Types ◽  
The Body ◽  
Receptor Expression ◽  
Conditional Knockout ◽  
Interleukin 4 ◽  
Virus Reactivation ◽  
Cell Type ◽  
Murine Gammaherpesvirus ◽  
Cell Type Specific

Gammaherpesviruses, such as Epstein-Barr virus (EBV), Kaposi’s sarcoma associated virus (KSHV), and murine γ-herpesvirus 68 (MHV68), establish latent infection in B cells, macrophages, and non-lymphoid cells, and can induce both lymphoid and non-lymphoid cancers. Research on these viruses has relied heavily on immortalized B cell and endothelial cell lines. Therefore, we know very little about the cell type specific regulation of virus infection. We have previously shown that treatment of MHV68-infected macrophages with the cytokine interleukin-4 (IL-4) or challenge of MHV68-infected mice with an IL-4-inducing parasite leads to virus reactivation. However, we do not know if all latent reservoirs of the virus, including B cells, reactivate the virus in response to IL-4. Here we used an in vivo approach to address the question of whether all latently infected cell types reactivate MHV68 in response to a particular stimulus. We found that IL-4 receptor expression on macrophages was required for IL-4 to induce virus reactivation, but that it was dispensable on B cells. We further demonstrated that the transcription factor, STAT6, which is downstream of the IL-4 receptor and binds virus gene 50 N4/N5 promoter in macrophages, did not bind to the virus gene 50 N4/N5 promoter in B cells. These data suggest that stimuli that promote herpesvirus reactivation may only affect latent virus in particular cell types, but not in others. Importance Herpesviruses establish life-long quiescent infections in specific cells in the body, and only reactivate to produce infectious virus when precise signals induce them to do so. The signals that induce herpesvirus reactivation are often studied only in one particular cell type infected with the virus. However, herpesviruses establish latency in multiple cell types in their hosts. Using murine gammaherpesvirus-68 (MHV68) and conditional knockout mice, we examined the cell type specificity of a particular reactivation signal, interleukin-4 (IL-4). We found that IL-4 only induced herpesvirus reactivation from macrophages, but not from B cells. This work indicates that regulation of virus latency and reactivation is cell type specific. This has important implications for therapies aimed at either promoting or inhibiting reactivation for the control or elimination of chronic viral infections.

scholarly journals A community-based transcriptomics classification and nomenclature of neocortical cell types

2020 ◽  
Vol 23 (12) ◽  
pp. 1456-1468 ◽  
Author(s):  
Rafael Yuste ◽  
Michael Hawrylycz ◽  
Nadia Aalling ◽  
Argel Aguilar-Valles ◽  
Detlev Arendt ◽  
...  
Keyword(s):  
Data Aggregation ◽  
Developmental Stages ◽  
Cell Types ◽  
The Body ◽  
Cortical Circuits ◽  
Cell Type ◽  
Community Based ◽  
Cortical Cells ◽  
Molecular Features ◽  
Definition Of

AbstractTo understand the function of cortical circuits, it is necessary to catalog their cellular diversity. Past attempts to do so using anatomical, physiological or molecular features of cortical cells have not resulted in a unified taxonomy of neuronal or glial cell types, partly due to limited data. Single-cell transcriptomics is enabling, for the first time, systematic high-throughput measurements of cortical cells and generation of datasets that hold the promise of being complete, accurate and permanent. Statistical analyses of these data reveal clusters that often correspond to cell types previously defined by morphological or physiological criteria and that appear conserved across cortical areas and species. To capitalize on these new methods, we propose the adoption of a transcriptome-based taxonomy of cell types for mammalian neocortex. This classification should be hierarchical and use a standardized nomenclature. It should be based on a probabilistic definition of a cell type and incorporate data from different approaches, developmental stages and species. A community-based classification and data aggregation model, such as a knowledge graph, could provide a common foundation for the study of cortical circuits. This community-based classification, nomenclature and data aggregation could serve as an example for cell type atlases in other parts of the body.

scholarly journals Cell-Free DNA Plasma Levels Differ in Age-Specific Pattern in Healthy Rats and Castrates with Testosterone-Induced Benign Prostatic Hyperplasia

2019 ◽  
Vol 2019 ◽  
pp. 1-6 ◽  
Author(s):  
I. N. Vasilyeva ◽  
V. G. Bespalov ◽  
J. D. Von ◽  
A. L. Semenov ◽  
G. V. Tochilnikov ◽  
...  
Keyword(s):  
Benign Prostatic Hyperplasia ◽  
Wistar Rats ◽  
Specific Pattern ◽  
Prostatic Hyperplasia ◽  
The Body ◽  
Cell Free Dna ◽  
Young Rats ◽  
Free Dna ◽  
Male Wistar Rats ◽  
Old Rats

The purpose of this work was to study changes in the level of cell-free DNA (cfDNA) in the blood of young and old rats in the normal state and with induced benign prostatic hyperplasia (BPH). Male Wistar rats were divided into 4 groups—young (3 months), old (20 months), intact, or with testosterone-induced BPH. Groups with BPH were subjected to surgical castration and administration of testosterone esters at a dose of 25 mg/kg for a total of 7 injections for 20 days. In intact animals, the level of cfDNA in old rats (2.00±0.14 ng/μl) was significantly higher than that in the young (1.02±0.30 ng/μl). The body and the prostate weights of old rats were 1.6 and 1.4 times larger than those of the young, without an increase in the prostate index (PI). The testosterone level in the blood of young rats was 1.6 times higher than that of old (6.20±0.93 nmol/l vs. 3.77±0.55 nmol/l; NS). In animals with BPH, the level of cfDNA in old rats (3.14±0.76 ng/μl) was significantly higher than that in young rats (0.80±0.14 ng/μl). The body and the prostate weights in old rats were 1.8 and 2.3 times larger, than those in young rats, with an increase in the PI. The level of testosterone in the blood of young (15.76±0.51 nmol/l) and old (16.99±1.1 nmol/l) rats was not significantly different. Morphological signs of BPH were observed in the prostate of both young and old rats. During the induction of BPH in the experiment, according to the level of cfDNA, cell death processes have not changed significantly in young rats but significantly increased in old rats. A similar trend was observed in the group of intact animals. The obtained data indicate that apoptosis processes are enhanced during the development of BPH despite the growth of tissues in the prostate itself.

Genome-wide detection of additional fetal chromosomal abnormalities by cell-free DNA testing of 15,626 consecutive pregnant women

2018 ◽  
Vol 62 (2) ◽  
pp. 215-224 ◽  
Author(s):  
Hong Yao ◽  
Ya Gao ◽  
Jia Zhao ◽  
Rong Zhang ◽  
Huixin Xu ◽  
...  
Keyword(s):  
Pregnant Women ◽  
Chromosomal Abnormalities ◽  
Dna Testing ◽  
Cell Free Dna ◽  
Free Dna ◽  
Genome Wide

scholarly journals CHETAH: a selective, hierarchical cell type identification method for single-cell RNA sequencing

2019 ◽  
Vol 47 (16) ◽  
pp. e95-e95 ◽  
Author(s):  
Jurrian K de Kanter ◽  
Philip Lijnzaad ◽  
Tito Candelli ◽  
Thanasis Margaritis ◽  
Frank C P Holstege
Keyword(s):  
Single Cell ◽  
Rna Sequencing ◽  
Reference Data ◽  
Classification Tree ◽  
Cell Types ◽  
Biological Information ◽  
Identification Algorithm ◽  
Intermediate Cell ◽  
Cell Type ◽  
Single Cell Rna Sequencing

Abstract Cell type identification is essential for single-cell RNA sequencing (scRNA-seq) studies, currently transforming the life sciences. CHETAH (CHaracterization of cEll Types Aided by Hierarchical classification) is an accurate cell type identification algorithm that is rapid and selective, including the possibility of intermediate or unassigned categories. Evidence for assignment is based on a classification tree of previously available scRNA-seq reference data and includes a confidence score based on the variance in gene expression per cell type. For cell types represented in the reference data, CHETAH’s accuracy is as good as existing methods. Its specificity is superior when cells of an unknown type are encountered, such as malignant cells in tumor samples which it pinpoints as intermediate or unassigned. Although designed for tumor samples in particular, the use of unassigned and intermediate types is also valuable in other exploratory studies. This is exemplified in pancreas datasets where CHETAH highlights cell populations not well represented in the reference dataset, including cells with profiles that lie on a continuum between that of acinar and ductal cell types. Having the possibility of unassigned and intermediate cell types is pivotal for preventing misclassification and can yield important biological information for previously unexplored tissues.

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