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Zaslavsky ME, Craig E, Michuda JK, Sehgal N, Ram-Mohan N, Lee JY, Nguyen KD, Hoh RA, Pham TD, Röltgen K, Lam B, Parsons ES, Macwana SR, DeJager W, Drapeau EM, Roskin KM, Cunningham-Rundles C, Moody MA, Haynes BF, Goldman JD, Heath JR, Nadeau KC, Pinsky BA, Blish CA, Hensley SE, Jensen K, Meyer E, Balboni I, Utz PJ, Merrill JT, Guthridge JM, James JA, Yang S, Tibshirani R, Kundaje A, Boyd SD. Disease diagnostics using machine learning of immune receptors. bioRxiv 2024:2022.04.26.489314. [PMID: 35547855 PMCID: PMC9094102 DOI: 10.1101/2022.04.26.489314] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Clinical diagnosis typically incorporates physical examination, patient history, and various laboratory tests and imaging studies, but makes limited use of the human system's own record of antigen exposures encoded by receptors on B cells and T cells. We analyzed immune receptor datasets from 593 individuals to develop MAchine Learning for Immunological Diagnosis (Mal-ID) , an interpretive framework to screen for multiple illnesses simultaneously or precisely test for one condition. This approach detects specific infections, autoimmune disorders, vaccine responses, and disease severity differences. Human-interpretable features of the model recapitulate known immune responses to SARS-CoV-2, Influenza, and HIV, highlight antigen-specific receptors, and reveal distinct characteristics of Systemic Lupus Erythematosus and Type-1 Diabetes autoreactivity. This analysis framework has broad potential for scientific and clinical interpretation of human immune responses.
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2
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Abe R, Ram-Mohan N, Yang S. Re-visiting humoral constitutive antibacterial heterogeneity in bloodstream infections. Lancet Infect Dis 2024; 24:e245-e251. [PMID: 37944543 DOI: 10.1016/s1473-3099(23)00494-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Revised: 07/03/2023] [Accepted: 07/25/2023] [Indexed: 11/12/2023]
Abstract
Although cellular immunity has garnered much attention in the era of single-cell technologies, humoral innate immunity has receded in priority due to its presumed limited roles. Hence, despite the long-recognised bactericidal activity of serum-a functional characteristic of constitutive humoral immunity-much remains unclear regarding mechanisms underlying its inter-individual heterogeneity and clinical implications in bloodstream infections. Recent work suggests that the immediate antimicrobial effect of humoral innate immunity contributes to suppression of the excessive inflammatory responses to infection by reducing the amount of pathogen-associated molecular patterns. In this Personal View, we propose the need to re-explore factors underlying the inter-individual heterogeneity in serum antibacterial competence as a new approach to better understand humoral innate immunity and revisit the clinical use of measuring serum antibacterial activity in the management of bacterial bloodstream infections. Given the current emphasis on subtyping sepsis, a serum bactericidal assay might prove useful in defining a distinct sepsis endotype, to enable more personalised management.
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Affiliation(s)
- Ryuichiro Abe
- Department of Emergency Medicine, Stanford University School of Medicine, Palo Alto, CA, USA
| | - Nikhil Ram-Mohan
- Department of Emergency Medicine, Stanford University School of Medicine, Palo Alto, CA, USA
| | - Samuel Yang
- Department of Emergency Medicine, Stanford University School of Medicine, Palo Alto, CA, USA.
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3
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Ku TH, Ram-Mohan N, Zudock EJ, Abe R, Yang S. Neutrophil Extracellular Traps have DNAzyme activity that drives bactericidal potential. bioRxiv 2023:2023.10.23.563618. [PMID: 37961380 PMCID: PMC10634746 DOI: 10.1101/2023.10.23.563618] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
The mechanisms of bacterial killing by neutrophil extracellular traps (NETs) are unclear. DNA, the largest component of NETs is believed to merely be a scaffold with minimal antimicrobial activity through the charge of the backbone. Here, we report that NETs DNA is beyond a scaffold and produces hydroxyl free radicals through the spatially concentrated G-quadruplex/hemin DNAzyme complexes, driving bactericidal effects. Immunofluorescence staining showed colocalization of G-quadruplex and hemin in extruded NETs DNA, and Amplex UltraRed assay portrayed its peroxidase activity. Proximity labeling of bacteria revealed localized concentration of radicals resulting from NETs bacterial trapping. Ex vivo bactericidal assays revealed that G-quadruplex/hemin DNAzyme is the primary driver of bactericidal activity in NETs. NETs are DNAzymes that may have important biological consequences.
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Affiliation(s)
- Ti-Hsuan Ku
- Department of Emergency Medicine, Stanford University, Stanford, CA 94305, United States
| | - Nikhil Ram-Mohan
- Department of Emergency Medicine, Stanford University, Stanford, CA 94305, United States
| | - Elizabeth J Zudock
- Department of Emergency Medicine, Stanford University, Stanford, CA 94305, United States
| | - Ryuichiro Abe
- Department of Emergency Medicine, Stanford University, Stanford, CA 94305, United States
| | - Samuel Yang
- Department of Emergency Medicine, Stanford University, Stanford, CA 94305, United States
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4
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Haddock NL, Barkal LJ, Ram-Mohan N, Kaber G, Chiu CY, Bhatt AS, Yang S, Bollyky PL. Phage diversity in cell-free DNA identifies bacterial pathogens in human sepsis cases. Nat Microbiol 2023; 8:1495-1507. [PMID: 37308590 PMCID: PMC10911932 DOI: 10.1038/s41564-023-01406-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Accepted: 05/10/2023] [Indexed: 06/14/2023]
Abstract
Bacteriophages, viruses that infect bacteria, have great specificity for their bacterial hosts at the strain and species level. However, the relationship between the phageome and associated bacterial population dynamics is unclear. Here we generated a computational pipeline to identify sequences associated with bacteriophages and their bacterial hosts in cell-free DNA from plasma samples. Analysis of two independent cohorts, including a Stanford Cohort of 61 septic patients and 10 controls and the SeqStudy cohort of 224 septic patients and 167 controls, reveals a circulating phageome in the plasma of all sampled individuals. Moreover, infection is associated with overrepresentation of pathogen-specific phages, allowing for identification of bacterial pathogens. We find that information on phage diversity enables identification of the bacteria that produced these phages, including pathovariant strains of Escherichia coli. Phage sequences can likewise be used to distinguish between closely related bacterial species such as Staphylococcus aureus, a frequent pathogen, and coagulase-negative Staphylococcus, a frequent contaminant. Phage cell-free DNA may have utility in studying bacterial infections.
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Affiliation(s)
- Naomi L Haddock
- Immunology Program, School of Medicine, Stanford University, Stanford, CA, USA
| | - Layla J Barkal
- Division of Pulmonary, Allergy, and Critical Care Medicine, School of Medicine, Stanford University, Stanford, CA, USA
| | - Nikhil Ram-Mohan
- Department of Emergency Medicine, School of Medicine, Stanford University, Stanford, CA, USA
| | - Gernot Kaber
- Department of Pediatrics, School of Medicine, Stanford University, Stanford, CA, USA
| | - Charles Y Chiu
- Department of Medicine, Division of Infectious Diseases, University of California San Francisco, San Francisco, CA, USA
| | - Ami S Bhatt
- Division of Hematology, School of Medicine, Stanford University, Stanford, CA, USA
- Department of Genetics, Stanford University, Stanford, CA, USA
| | - Samuel Yang
- Department of Emergency Medicine, School of Medicine, Stanford University, Stanford, CA, USA
| | - Paul L Bollyky
- Division of Infectious Diseases and Geographic Medicine, School of Medicine, Stanford University, Stanford, CA, USA.
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5
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Tjandra KC, Ram-Mohan N, Abe R, Wang TH, Yang S. Rapid Molecular Phenotypic Antimicrobial Susceptibility Test for Neisseria gonorrhoeae Based on Propidium Monoazide Viability PCR. ACS Infect Dis 2023; 9:1160-1167. [PMID: 37115656 DOI: 10.1021/acsinfecdis.3c00096] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/29/2023]
Abstract
Neisseria gonorrhoeae (NG) is an urgent threat to antimicrobial resistance (AMR) worldwide. NG has acquired rapid resistance to all previously recommended treatments, leaving ceftriaxone monotherapy as the first and last line of therapy for uncomplicated NG. The ability to rapidly determine susceptibility, which is currently nonexistent for NG, has been proposed as a strategy to preserve ceftriaxone by using alternative treatments. Herein, we used a DNA-intercalating dye in combination with NG-specific primers/probes to generate qPCR cycle threshold (Ct) values at different concentrations of 2 NG-relevant antimicrobials. Our proof-of-concept dual-antimicrobial logistic regression model based on the differential Ct measurements achieved an AUC of 0.93 with a categorical agreement for the susceptibility of 84.6%. When surveying the performance against each antimicrobial separately, the model predicted 90 and 75% susceptible and resistant strains, respectively, to ceftriaxone and 66.7 and 83.3% susceptible and resistant strains, respectively, to ciprofloxacin. We further validated the model against the individual replicates and determined the accuracy of the model in classifying susceptibility agnostic of the inoculum size. We demonstrated a novel PCR-based approach to determine phenotypic ciprofloxacin and ceftriaxone susceptibility information for NG with reasonable accuracy within 30 min, a significant improvement compared to the conventional method which could take multiple days.
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Affiliation(s)
- Kristel C Tjandra
- Department of Emergency Medicine, Stanford University School of Medicine, Palo Alto, California 94305, United States
| | - Nikhil Ram-Mohan
- Department of Emergency Medicine, Stanford University School of Medicine, Palo Alto, California 94305, United States
| | - Ryuichiro Abe
- Department of Emergency Medicine, Stanford University School of Medicine, Palo Alto, California 94305, United States
| | - Tza-Huei Wang
- Departments of Mechanical Engineering and Biomedical Engineering, The Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Samuel Yang
- Department of Emergency Medicine, Stanford University School of Medicine, Palo Alto, California 94305, United States
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Tjandra KC, Ram-Mohan N, Abe R, Wang TH, Yang S. Rapid molecular phenotypic antimicrobial susceptibility test for Neisseria gonorrhoeae based on propidium monoazide viability PCR. bioRxiv 2023:2023.03.01.530513. [PMID: 36909582 PMCID: PMC10002740 DOI: 10.1101/2023.03.01.530513] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/06/2023]
Abstract
Neisseria gonorrhoeae (NG) is an urgent threat to antimicrobial resistance (AMR) worldwide. NG has acquired rapid resistance to all previously recommended treatments leaving ceftriaxone monotherapy as the first and last line of therapy for uncomplicated NG. The ability to rapidly determine susceptibility, which is currently nonexistent for NG, has been proposed as a strategy to preserve ceftriaxone by using alternative treatments. Herein, we used a DNA-intercalating dye in combination with NG-specific primers/probes to generate qPCR cycle threshold (Ct) values at different concentrations of 2 NG-relevant antimicrobials. Our proof of concept dual-antimicrobial logistic regression model based on the differential Ct measurements achieved an AUC of 0.93 with a categorical agreement for susceptibility of 84.6%. When surveying the performance against each antimicrobial separately, the model predicted 90% and 75% susceptible and resistant strains respectively to ceftriaxone and 66.7% and 83.3% susceptible and resistant strains respectively to ciprofloxacin. We further validated the model against the individual replicates and determined the accuracy of the model in classifying susceptibility agnostic of the inoculum size. We demonstrated a novel PCR-based approach to determine phenotypic ciprofloxacin and ceftriaxone susceptibility information for NG with reasonable accuracy in under 30 min, a significant improvement compared to the conventional method which takes 3 days. Table of Content Graphic
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Affiliation(s)
- Kristel C Tjandra
- Department of Emergency Medicine, Stanford University School of Medicine, Palo Alto, CA, USA
| | - Nikhil Ram-Mohan
- Department of Emergency Medicine, Stanford University School of Medicine, Palo Alto, CA, USA
| | - Ryuichiro Abe
- Department of Emergency Medicine, Stanford University School of Medicine, Palo Alto, CA, USA
| | - Tza-Huei Wang
- Departments of Mechanical Engineering and Biomedical Engineering, The Johns Hopkins University, Baltimore, Maryland, USA
| | - Samuel Yang
- Department of Emergency Medicine, Stanford University School of Medicine, Palo Alto, CA, USA
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Ram-Mohan N, Rogers AJ, Blish CA, Nadeau KC, Zudock EJ, Kim D, Quinn JV, Sun L, Liesenfeld O, Yang S. Using a 29-mRNA Host Response Classifier To Detect Bacterial Coinfections and Predict Outcomes in COVID-19 Patients Presenting to the Emergency Department. Microbiol Spectr 2022; 10:e0230522. [PMID: 36250865 PMCID: PMC9769905 DOI: 10.1128/spectrum.02305-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2022] [Accepted: 09/26/2022] [Indexed: 01/06/2023] Open
Abstract
Clinicians in the emergency department (ED) face challenges in concurrently assessing patients with suspected COVID-19 infection, detecting bacterial coinfection, and determining illness severity since current practices require separate workflows. Here, we explore the accuracy of the IMX-BVN-3/IMX-SEV-3 29 mRNA host response classifiers in simultaneously detecting severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and bacterial coinfections and predicting clinical severity of COVID-19. A total of 161 patients with PCR-confirmed COVID-19 (52.2% female; median age, 50.0 years; 51% hospitalized; 5.6% deaths) were enrolled at the Stanford Hospital ED. RNA was extracted (2.5 mL whole blood in PAXgene blood RNA), and 29 host mRNAs in response to the infection were quantified using Nanostring nCounter. The IMX-BVN-3 classifier identified SARS-CoV-2 infection in 151 patients with a sensitivity of 93.8%. Six of 10 patients undetected by the classifier had positive COVID tests more than 9 days prior to enrollment, and the remaining patients oscillated between positive and negative results in subsequent tests. The classifier also predicted that 6 (3.7%) patients had a bacterial coinfection. Clinical adjudication confirmed that 5/6 (83.3%) of the patients had bacterial infections, i.e., Clostridioides difficile colitis (n = 1), urinary tract infection (n = 1), and clinically diagnosed bacterial infections (n = 3), for a specificity of 99.4%. Two of 101 (2.8%) patients in the IMX-SEV-3 "Low" severity classification and 7/60 (11.7%) in the "Moderate" severity classification died within 30 days of enrollment. IMX-BVN-3/IMX-SEV-3 classifiers accurately identified patients with COVID-19 and bacterial coinfections and predicted patients' risk of death. A point-of-care version of these classifiers, under development, could improve ED patient management, including more accurate treatment decisions and optimized resource utilization. IMPORTANCE We assay the utility of the single-test IMX-BVN-3/IMX-SEV-3 classifiers that require just 2.5 mL of patient blood in concurrently detecting viral and bacterial infections as well as predicting the severity and 30-day outcome from the infection. A point-of-care device, in development, will circumvent the need for blood culturing and drastically reduce the time needed to detect an infection. This will negate the need for empirical use of broad-spectrum antibiotics and allow for antibiotic use stewardship. Additionally, accurate classification of the severity of infection and the prediction of 30-day severe outcomes will allow for appropriate allocation of hospital resources.
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Affiliation(s)
- Nikhil Ram-Mohan
- Department of Emergency Medicine, Stanford University School of Medicine, Stanford, California, USA
| | - Angela J. Rogers
- Department of Medicine—Pulmonary, Allergy & Critical Care Medicine, Stanford University School of Medicine, Stanford, California, USA
| | - Catherine A. Blish
- Department of Medicine/Infectious Diseases, Stanford University School of Medicine, Stanford, California, USA
| | - Kari C. Nadeau
- Department of Medicine—Pulmonary, Allergy & Critical Care Medicine, Stanford University School of Medicine, Stanford, California, USA
| | - Elizabeth J. Zudock
- Department of Emergency Medicine, Stanford University School of Medicine, Stanford, California, USA
| | - David Kim
- Department of Emergency Medicine, Stanford University School of Medicine, Stanford, California, USA
| | - James V. Quinn
- Department of Emergency Medicine, Stanford University School of Medicine, Stanford, California, USA
| | - Lixian Sun
- Inflammatix, Inc., Burlingame, California, USA
| | | | - The Stanford COVID-19 Biobank Study Group
- Department of Emergency Medicine, Stanford University School of Medicine, Stanford, California, USA
- Department of Medicine—Pulmonary, Allergy & Critical Care Medicine, Stanford University School of Medicine, Stanford, California, USA
- Department of Medicine/Infectious Diseases, Stanford University School of Medicine, Stanford, California, USA
- Inflammatix, Inc., Burlingame, California, USA
| | - Samuel Yang
- Department of Emergency Medicine, Stanford University School of Medicine, Stanford, California, USA
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Ram-Mohan N, Rogers AJ, Blish CA, Nadeau KC, Zudock EJ, Kim D, Quinn JV, Sun L, Liesenfeld O, Yang S. Detection of bacterial co-infections and prediction of fatal outcomes in COVID-19 patients presenting to the emergency department using a 29 mRNA host response classifier. medRxiv 2022:2022.03.14.22272394. [PMID: 35313598 PMCID: PMC8936113 DOI: 10.1101/2022.03.14.22272394] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Objective Clinicians in the emergency department (ED) face challenges in concurrently assessing patients with suspected COVID-19 infection, detecting bacterial co-infection, and determining illness severity since current practices require separate workflows. Here we explore the accuracy of the IMX-BVN-3/IMX-SEV-3 29 mRNA host response classifiers in simultaneously detecting SARS-CoV-2 infection, bacterial co-infections, and predicting clinical severity of COVID-19. Methods 161 patients with PCR-confirmed COVID-19 (52.2% female, median age 50.0 years, 51% hospitalized, 5.6% deaths) were enrolled at the Stanford Hospital ED. RNA was extracted (2.5 mL whole blood in PAXgene Blood RNA) and 29 host mRNAs in response to the infection were quantified using Nanostring nCounter. Results The IMX-BVN-3 classifier identified SARS-CoV-2 infection in 151 patients with a sensitivity of 93.8%. Six of 10 patients undetected by the classifier had positive COVID tests more than 9 days prior to enrolment and the remaining oscillated between positive and negative results in subsequent tests. The classifier also predicted that 6 (3.7%) patients had a bacterial co-infection. Clinical adjudication confirmed that 5/6 (83.3%) of the patients had bacterial infections, i.e. Clostridioides difficile colitis (n=1), urinary tract infection (n=1), and clinically diagnosed bacterial infections (n=3) for a specificity of 99.4%. 2/101 (2.8%) patients in the IMX-SEV-3 Low and 7/60 (11.7%) in the Moderate severity classifications died within thirty days of enrollment. Conclusions IMX-BVN-3/IMX-SEV-3 classifiers accurately identified patients with COVID-19, bacterial co-infections, and predicted patients’ risk of death. A point-of-care version of these classifiers, under development, could improve ED patient management including more accurate treatment decisions and optimized resource utilization.
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Affiliation(s)
- Nikhil Ram-Mohan
- Department of Emergency Medicine, Stanford University School of Medicine, Palo Alto, CA, USA
| | - Angela J. Rogers
- Department of Medicine-Pulmonary, Allergy & Critical Care Medicine, Stanford University School of Medicine, Palo Alto, CA, USA
| | - Catherine A. Blish
- Department of Medicine/Infectious Diseases, Stanford University School of Medicine, Palo Alto, CA, USA
| | - Kari C. Nadeau
- Department of Medicine-Pulmonary, Allergy & Critical Care Medicine, Stanford University School of Medicine, Palo Alto, CA, USA
| | - Elizabeth J Zudock
- Department of Emergency Medicine, Stanford University School of Medicine, Palo Alto, CA, USA
| | - David Kim
- Department of Emergency Medicine, Stanford University School of Medicine, Palo Alto, CA, USA
| | - James V. Quinn
- Department of Emergency Medicine, Stanford University School of Medicine, Palo Alto, CA, USA
| | | | | | | | - Samuel Yang
- Department of Emergency Medicine, Stanford University School of Medicine, Palo Alto, CA, USA
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Ram-Mohan N, Kim D, Rogers AJ, Blish CA, Nadeau K, Blomkalns AL, Yang S. Association Between SARS-CoV-2 RNAemia and Postacute Sequelae of COVID-19. Open Forum Infect Dis 2022; 9:ofab646. [PMID: 35111870 PMCID: PMC8802799 DOI: 10.1093/ofid/ofab646] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Accepted: 12/24/2021] [Indexed: 11/17/2022] Open
Abstract
Determinants of Post-Acute Sequelae of COVID-19 are not known. Here we show that 83.3% of patients with viral RNA in blood (RNAemia) at presentation were symptomatic in the post-acute phase. RNAemia at presentation successfully predicted PASC, independent of patient demographics, worst disease severity, and length of symptoms.
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Affiliation(s)
- Nikhil Ram-Mohan
- Department of Emergency Medicine, Stanford University School of Medicine, Palo Alto, California, USA
| | - David Kim
- Department of Emergency Medicine, Stanford University School of Medicine, Palo Alto, California, USA
| | - Angela J Rogers
- Department of Medicine—Pulmonary, Allergy & Critical Care Medicine, Stanford University School of Medicine, Palo Alto, California, USA
| | - Catherine A Blish
- Department of Medicine/Infectious Diseases, Stanford University School of Medicine, Palo Alto, California, USA
| | - Kari C Nadeau
- Department of Medicine—Pulmonary, Allergy & Critical Care Medicine, Stanford University School of Medicine, Palo Alto, California, USA
| | - Andra L Blomkalns
- Department of Emergency Medicine, Stanford University School of Medicine, Palo Alto, California, USA
| | - Samuel Yang
- Department of Emergency Medicine, Stanford University School of Medicine, Palo Alto, California, USA
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Ram-Mohan N, Kim D, Zudock EJ, Hashemi MM, Tjandra KC, Rogers AJ, Blish CA, Nadeau KC, Newberry JA, Quinn JV, O'Hara R, Ashley E, Nguyen H, Jiang L, Hung P, Blomkalns AL, Yang S. SARS-CoV-2 RNAemia Predicts Clinical Deterioration and Extrapulmonary Complications from COVID-19. Clin Infect Dis 2022; 74:218-226. [PMID: 33949665 PMCID: PMC8135992 DOI: 10.1093/cid/ciab394] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2021] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND The determinants of coronavirus disease 2019 (COVID-19) disease severity and extrapulmonary complications (EPCs) are poorly understood. We characterized relationships between severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNAemia and disease severity, clinical deterioration, and specific EPCs. METHODS We used quantitative and digital polymerase chain reaction (qPCR and dPCR) to quantify SARS-CoV-2 RNA from plasma in 191 patients presenting to the emergency department with COVID-19. We recorded patient symptoms, laboratory markers, and clinical outcomes, with a focus on oxygen requirements over time. We collected longitudinal plasma samples from a subset of patients. We characterized the role of RNAemia in predicting clinical severity and EPCs using elastic net regression. RESULTS Of SARS-CoV-2-positive patients, 23.0% (44 of 191) had viral RNA detected in plasma by dPCR, compared with 1.4% (2 of 147) by qPCR. Most patients with serial measurements had undetectable RNAemia within 10 days of symptom onset, reached maximum clinical severity within 16 days, and symptom resolution within 33 days. Initially RNAemic patients were more likely to manifest severe disease (odds ratio, 6.72 [95% confidence interval, 2.45-19.79]), worsening of disease severity (2.43 [1.07-5.38]), and EPCs (2.81 [1.26-6.36]). RNA loads were correlated with maximum severity (r = 0.47 [95% confidence interval, .20-.67]). CONCLUSIONS dPCR is more sensitive than qPCR for the detection of SARS-CoV-2 RNAemia, which is a robust predictor of eventual COVID-19 severity and oxygen requirements, as well as EPCs. Because many COVID-19 therapies are initiated on the basis of oxygen requirements, RNAemia on presentation might serve to direct early initiation of appropriate therapies for the patients most likely to deteriorate.
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Affiliation(s)
- Nikhil Ram-Mohan
- Department of Emergency Medicine, Stanford University School of Medicine, Palo Alto, California, USA
| | - David Kim
- Department of Emergency Medicine, Stanford University School of Medicine, Palo Alto, California, USA
| | - Elizabeth J Zudock
- Department of Emergency Medicine, Stanford University School of Medicine, Palo Alto, California, USA
| | - Marjan M Hashemi
- Department of Emergency Medicine, Stanford University School of Medicine, Palo Alto, California, USA
| | - Kristel C Tjandra
- Department of Emergency Medicine, Stanford University School of Medicine, Palo Alto, California, USA
| | - Angela J Rogers
- Department of Medicine-Pulmonary, Allergy & Critical Care Medicine, Stanford University School of Medicine, Palo Alto, California, USA
| | - Catherine A Blish
- Department of Medicine/Infectious Diseases, Stanford University School of Medicine, Palo Alto, California, USA
| | - Kari C Nadeau
- Department of Medicine-Pulmonary, Allergy & Critical Care Medicine, Stanford University School of Medicine, Palo Alto, California, USA
| | - Jennifer A Newberry
- Department of Emergency Medicine, Stanford University School of Medicine, Palo Alto, California, USA
| | - James V Quinn
- Department of Emergency Medicine, Stanford University School of Medicine, Palo Alto, California, USA
| | - Ruth O'Hara
- Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Palo Alto, California, USA
| | - Euan Ashley
- Department of Medicine-Cardiovascular Medicine, Stanford University School of Medicine, Palo Alto, California, USA
| | | | | | - Paul Hung
- Combinati Inc, Palo Alto, California, USA
| | - Andra L Blomkalns
- Department of Emergency Medicine, Stanford University School of Medicine, Palo Alto, California, USA
| | - Samuel Yang
- Department of Emergency Medicine, Stanford University School of Medicine, Palo Alto, California, USA
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Ram-Mohan N, Kim D, Rogers AJ, Blish CA, Nadeau KC, Blomkalns AL, Yang S. Association Between SARS-CoV-2 RNAemia and Post-Acute Sequelae of COVID-19. medRxiv 2021:2021.09.03.21262934. [PMID: 34518843 PMCID: PMC8437320 DOI: 10.1101/2021.09.03.21262934] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Determinants of Post-Acute Sequelae of COVID-19 are not known. Here we show that 75% of patients with viral RNA in blood (RNAemia) at presentation were symptomatic in the post-acute phase. RNAemia at presentation successfully predicted PASC, independent of patient demographics, initial disease severity, and length of symptoms.
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Affiliation(s)
- Nikhil Ram-Mohan
- Department of Emergency Medicine, Stanford University School of Medicine, Palo Alto CA 94305 USA
| | - David Kim
- Department of Emergency Medicine, Stanford University School of Medicine, Palo Alto CA 94305 USA
| | - Angela J Rogers
- Department of Medicine - Pulmonary, Allergy & Critical Care Medicine, Stanford University School of Medicine, Palo Alto CA 94305 USA
| | - Catherine A Blish
- Department of Medicine/Infectious Diseases, Stanford University School of Medicine, Palo Alto CA 94305 USA
| | - Kari C Nadeau
- Department of Medicine - Pulmonary, Allergy & Critical Care Medicine, Stanford University School of Medicine, Palo Alto CA 94305 USA
| | - Andra L Blomkalns
- Department of Emergency Medicine, Stanford University School of Medicine, Palo Alto CA 94305 USA
| | - Samuel Yang
- Department of Emergency Medicine, Stanford University School of Medicine, Palo Alto CA 94305 USA
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Ram-Mohan N, Thair SA, Litzenburger UM, Cogill S, Andini N, Yang X, Chang HY, Yang S. Profiling chromatin accessibility responses in human neutrophils with sensitive pathogen detection. Life Sci Alliance 2021; 4:4/8/e202000976. [PMID: 34145026 PMCID: PMC8321655 DOI: 10.26508/lsa.202000976] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Revised: 06/07/2021] [Accepted: 06/08/2021] [Indexed: 12/13/2022] Open
Abstract
ATAC-seq reveals unique neutrophil chromatin architecture changes in response to different stimuli before transcriptional activation, possibly regulating downstream gene expression. Sepsis, sequela of bloodstream infections and dysregulated host responses, is a leading cause of death globally. Neutrophils tightly regulate responses to pathogens to prevent organ damage. Profiling early host epigenetic responses in neutrophils may aid in disease recognition. We performed assay for transposase-accessible chromatin (ATAC)-seq of human neutrophils challenged with six toll-like receptor ligands and two organisms; and RNA-seq after Escherichia coli exposure for 1 and 4 h along with ATAC-seq. ATAC-seq of neutrophils facilitates detection of pathogen DNA. In addition, despite similarities in genomic distribution of differential chromatin changes across challenges, only a fraction overlaps between the challenges. Ligands depict shared signatures, but majority are unique in position, function, and challenge. Epigenomic changes are plastic, only ∼120 are shared by E. coli challenges over time, resulting in varied differential genes and associated processes. We identify three classes of gene regulation, chromatin access changes in the promoter; changes in the promoter and distal enhancers; and controlling expression through changes solely in distal enhancers. These and transcription factor footprinting reveal timely and challenge specific mechanisms of transcriptional regulation in neutrophils.
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Affiliation(s)
- Nikhil Ram-Mohan
- Department of Emergency Medicine, Stanford University School of Medicine, Stanford, CA, USA
| | - Simone A Thair
- Department of Emergency Medicine, Stanford University School of Medicine, Stanford, CA, USA
| | | | - Steven Cogill
- Department of Emergency Medicine, Stanford University School of Medicine, Stanford, CA, USA
| | - Nadya Andini
- Department of Emergency Medicine, Stanford University School of Medicine, Stanford, CA, USA
| | - Xi Yang
- Department of Emergency Medicine, Stanford University School of Medicine, Stanford, CA, USA
| | - Howard Y Chang
- Center for Personal Dynamic Regulomes, Stanford University, Stanford, CA, USA
| | - Samuel Yang
- Department of Emergency Medicine, Stanford University School of Medicine, Stanford, CA, USA
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Ram-Mohan N, Kim D, Zudock EJ, Hashemi MM, Tjandra KC, Rogers AJ, Blish CA, Nadeau KC, Newberry JA, Quinn JV, O’Hara R, Ashley E, Nguyen H, Jiang L, Hung P, Blomkalns AL, Yang S. SARS-CoV-2 RNAaemia predicts clinical deterioration and extrapulmonary complications from COVID-19. medRxiv 2020:2020.12.19.20248561. [PMID: 33398290 PMCID: PMC7781329 DOI: 10.1101/2020.12.19.20248561] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Background The determinants of COVID-19 disease severity and extrapulmonary complications (EPCs) are poorly understood. We characterise the relationships between SARS-CoV-2 RNAaemia and disease severity, clinical deterioration, and specific EPCs. Methods We used quantitative (qPCR) and digital (dPCR) PCR to quantify SARS-CoV-2 RNA from nasopharyngeal swabs and plasma in 191 patients presenting to the Emergency Department (ED) with COVID-19. We recorded patient symptoms, laboratory markers, and clinical outcomes, with a focus on oxygen requirements over time. We collected longitudinal plasma samples from a subset of patients. We characterised the role of RNAaemia in predicting clinical severity and EPCs using elastic net regression. Findings 23·0% (44/191) of SARS-CoV-2 positive patients had viral RNA detected in plasma by dPCR, compared to 1·4% (2/147) by qPCR. Most patients with serial measurements had undetectable RNAaemia 10 days after onset of symptoms, but took 16 days to reach maximum severity, and 33 days for symptoms to resolve. Initially RNAaemic patients were more likely to manifest severe disease (OR 6·72 [95% CI, 2·45 - 19·79]), worsening of disease severity (OR 2·43 [95% CI, 1·07 - 5·38]), and EPCs (OR 2·81 [95% CI, 1·26 - 6·36]). RNA load correlated with maximum severity (r = 0·47 [95% CI, 0·20 - 0·67]). Interpretation dPCR is more sensitive than qPCR for the detection of SARS-CoV-2 RNAaemia, which is a robust predictor of eventual COVID-19 severity and oxygen requirements, as well as EPCs. Since many COVID-19 therapies are initiated on the basis of oxygen requirements, RNAaemia on presentation might serve to direct early initiation of appropriate therapies for the patients most likely to deteriorate.
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Affiliation(s)
- Nikhil Ram-Mohan
- Department of Emergency Medicine, Stanford University School of Medicine, Palo Alto CA 94305
| | - David Kim
- Department of Emergency Medicine, Stanford University School of Medicine, Palo Alto CA 94305
| | - Elizabeth J Zudock
- Department of Emergency Medicine, Stanford University School of Medicine, Palo Alto CA 94305
| | - Marjan M Hashemi
- Department of Emergency Medicine, Stanford University School of Medicine, Palo Alto CA 94305
| | - Kristel C Tjandra
- Department of Emergency Medicine, Stanford University School of Medicine, Palo Alto CA 94305
| | - Angela J Rogers
- Department of Medicine - Pulmonary, Allergy & Critical Care Medicine, Stanford University School of Medicine, Palo Alto CA 94305
| | - Catherine A Blish
- Department of Medicine/Infectious Diseases, Stanford University School of Medicine, Palo Alto CA 94305
| | - Kari C. Nadeau
- Department of Medicine - Pulmonary, Allergy & Critical Care Medicine, Stanford University School of Medicine, Palo Alto CA 94305
| | - Jennifer A Newberry
- Department of Emergency Medicine, Stanford University School of Medicine, Palo Alto CA 94305
| | - James V Quinn
- Department of Emergency Medicine, Stanford University School of Medicine, Palo Alto CA 94305
| | - Ruth O’Hara
- Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Palo Alto CA 94305
| | - Euan Ashley
- Department of Medicine – Cardiovascular Medicine, Stanford University School of Medicine, Palo Alto CA 94305
| | - Hien Nguyen
- COMBiNATi Inc., 2450 Embarcadero Way, Palo Alto CA 94303
| | - Lingxia Jiang
- COMBiNATi Inc., 2450 Embarcadero Way, Palo Alto CA 94303
| | - Paul Hung
- COMBiNATi Inc., 2450 Embarcadero Way, Palo Alto CA 94303
| | | | - Andra L Blomkalns
- Department of Emergency Medicine, Stanford University School of Medicine, Palo Alto CA 94305
| | - Samuel Yang
- Department of Emergency Medicine, Stanford University School of Medicine, Palo Alto CA 94305
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Makkay AM, Louyakis AS, Ram-Mohan N, Gophna U, Gogarten JP, Papke RT. Insights into gene expression changes under conditions that facilitate horizontal gene transfer (mating) of a model archaeon. Sci Rep 2020; 10:22297. [PMID: 33339886 PMCID: PMC7749143 DOI: 10.1038/s41598-020-79296-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Accepted: 11/19/2020] [Indexed: 12/16/2022] Open
Abstract
Horizontal gene transfer is a means by which bacteria, archaea, and eukaryotes are able to trade DNA within and between species. While there are a variety of mechanisms through which this genetic exchange can take place, one means prevalent in the archaeon Haloferax volcanii involves the transient formation of cytoplasmic bridges between cells and is referred to as mating. This process can result in the exchange of very large fragments of DNA between the participating cells. Genes governing the process of mating, including triggers to initiate mating, mechanisms of cell fusion, and DNA exchange, have yet to be characterized. We used a transcriptomic approach to gain a more detailed knowledge of how mating might transpire. By examining the differential expression of genes expressed in cells harvested from mating conditions on a filter over time and comparing them to those expressed in a shaking culture, we were able to identify genes and pathways potentially associated with mating. These analyses provide new insights into both the mechanisms and barriers of mating in Hfx. volcanii.
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Affiliation(s)
- Andrea M Makkay
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT, USA
| | - Artemis S Louyakis
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT, USA
| | - Nikhil Ram-Mohan
- Department of Emergency Medicine, Stanford University School of Medicine, Stanford, CA, USA
| | - Uri Gophna
- The Shmunis School of Biomedicine and Cancer Research, Faculty of Life Sciences, Tel Aviv University, P.O. Box 39040, 6997801, Tel Aviv, Israel
| | - J Peter Gogarten
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT, USA.,Institute for Systems Genomics, University of Connecticut, Storrs, CT, USA
| | - R Thane Papke
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT, USA.
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15
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Ram-Mohan N, Meyer MM. Comparative Metatranscriptomics of Periodontitis Supports a Common Polymicrobial Shift in Metabolic Function and Identifies Novel Putative Disease-Associated ncRNAs. Front Microbiol 2020; 11:482. [PMID: 32328037 PMCID: PMC7160235 DOI: 10.3389/fmicb.2020.00482] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Accepted: 03/05/2020] [Indexed: 01/08/2023] Open
Abstract
Periodontitis is an inflammatory disease that deteriorates bone supporting teeth afflicting ∼743 million people worldwide. Bacterial communities associated with disease have been classified into red, orange, purple, blue, green, and yellow complexes based on their roles in the periodontal pocket. Previous metagenomic and metatranscriptomics analyses suggest a common shift in metabolic signatures in disease vs. healthy communities with up-regulated processes including pyruvate fermentation, histidine degradation, amino acid metabolism, TonB-dependent receptors. In this work, we examine existing metatranscriptome datasets to identify the commonly differentially expressed transcripts and potential underlying RNA regulatory mechanisms behind the metabolic shifts. Raw RNA-seq reads from three studies (including 49 healthy and 48 periodontitis samples) were assembled into transcripts de novo. Analyses revealed 859 differentially expressed (DE) transcripts, 675 more- and 174 less-expressed. Only ∼20% of the DE transcripts originate from the pathogenic red/orange complexes, and ∼50% originate from organisms unaffiliated with a complex. Comparison of expression profiles revealed variations among disease samples; while specific metabolic processes are commonly up-regulated, the underlying organisms are diverse both within and across disease associated communities. Surveying DE transcripts for known ncRNAs from the Rfam database identified a large number of tRNAs and tmRNAs as well as riboswitches (FMN, glycine, lysine, and SAM) in more prevalent transcripts and the cobalamin riboswitch in both more and less prevalent transcripts. In silico discovery identified many putative ncRNAs in DE transcripts. We report 15 such putative ncRNAs having promising covariation in the predicted secondary structure and interesting genomic context. Seven of these are antisense of ribosomal proteins that are novel and may involve maintaining ribosomal protein stoichiometry during the disease associated metabolic shift. Our findings describe the role of organisms previously unaffiliated with disease and identify the commonality in progression of disease across three metatranscriptomic studies. We find that although the communities are diverse between individuals, the switch in metabolic signatures characteristic of disease is typically achieved through the contributions of several community members. Furthermore, we identify many ncRNAs (both known and putative) which may facilitate the metabolic shifts associated with periodontitis.
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Affiliation(s)
- Nikhil Ram-Mohan
- Department of Biology, Boston College, Chestnut Hill, MA, United States
| | - Michelle M Meyer
- Department of Biology, Boston College, Chestnut Hill, MA, United States
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Crum M, Ram-Mohan N, Meyer MM. Regulatory context drives conservation of glycine riboswitch aptamers. PLoS Comput Biol 2019; 15:e1007564. [PMID: 31860665 PMCID: PMC6944388 DOI: 10.1371/journal.pcbi.1007564] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Revised: 01/06/2020] [Accepted: 11/25/2019] [Indexed: 12/13/2022] Open
Abstract
In comparison to protein coding sequences, the impact of mutation and natural selection on the sequence and function of non-coding (ncRNA) genes is not well understood. Many ncRNA genes are narrowly distributed to only a few organisms, and appear to be rapidly evolving. Compared to protein coding sequences, there are many challenges associated with assessment of ncRNAs that are not well addressed by conventional phylogenetic approaches, including: short sequence length, lack of primary sequence conservation, and the importance of secondary structure for biological function. Riboswitches are structured ncRNAs that directly interact with small molecules to regulate gene expression in bacteria. They typically consist of a ligand-binding domain (aptamer) whose folding changes drive changes in gene expression. The glycine riboswitch is among the most well-studied due to the widespread occurrence of a tandem aptamer arrangement (tandem), wherein two homologous aptamers interact with glycine and each other to regulate gene expression. However, a significant proportion of glycine riboswitches are comprised of single aptamers (singleton). Here we use graph clustering to circumvent the limitations of traditional phylogenetic analysis when studying the relationship between the tandem and singleton glycine aptamers. Graph clustering enables a broader range of pairwise comparison measures to be used to assess aptamer similarity. Using this approach, we show that one aptamer of the tandem glycine riboswitch pair is typically much more highly conserved, and that which aptamer is conserved depends on the regulated gene. Furthermore, our analysis also reveals that singleton aptamers are more similar to either the first or second tandem aptamer, again based on the regulated gene. Taken together, our findings suggest that tandem glycine riboswitches degrade into functional singletons, with the regulated gene(s) dictating which glycine-binding aptamer is conserved.
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Affiliation(s)
- Matt Crum
- Department of Biology, Boston College, Chestnut Hill, Massachusetts, United States of America
| | - Nikhil Ram-Mohan
- Department of Biology, Boston College, Chestnut Hill, Massachusetts, United States of America
| | - Michelle M. Meyer
- Department of Biology, Boston College, Chestnut Hill, Massachusetts, United States of America
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Warrier I, Ram-Mohan N, Zhu Z, Hazery A, Echlin H, Rosch J, Meyer MM, van Opijnen T. The Transcriptional landscape of Streptococcus pneumoniae TIGR4 reveals a complex operon architecture and abundant riboregulation critical for growth and virulence. PLoS Pathog 2018; 14:e1007461. [PMID: 30517198 PMCID: PMC6296669 DOI: 10.1371/journal.ppat.1007461] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2018] [Revised: 12/17/2018] [Accepted: 11/07/2018] [Indexed: 11/21/2022] Open
Abstract
Efficient and highly organized regulation of transcription is fundamental to an organism’s ability to survive, proliferate, and quickly respond to its environment. Therefore, precise mapping of transcriptional units and understanding their regulation is crucial to determining how pathogenic bacteria cause disease and how they may be inhibited. In this study, we map the transcriptional landscape of the bacterial pathogen Streptococcus pneumoniae TIGR4 by applying a combination of high-throughput RNA-sequencing techniques. We successfully map 1864 high confidence transcription termination sites (TTSs), 790 high confidence transcription start sites (TSSs) (742 primary, and 48 secondary), and 1360 low confidence TSSs (74 secondary and 1286 primary) to yield a total of 2150 TSSs. Furthermore, our study reveals a complex transcriptome wherein environment-respondent alternate transcriptional units are observed within operons stemming from internal TSSs and TTSs. Additionally, we identify many putative cis-regulatory RNA elements and riboswitches within 5’-untranslated regions (5’-UTR). By integrating TSSs and TTSs with independently collected RNA-Seq datasets from a variety of conditions, we establish the response of these regulators to changes in growth conditions and validate several of them. Furthermore, to demonstrate the importance of ribo-regulation by 5’-UTR elements for in vivo virulence, we show that the pyrR regulatory element is essential for survival, successful colonization and infection in mice suggesting that such RNA elements are potential drug targets. Importantly, we show that our approach of combining high-throughput sequencing with in vivo experiments can reconstruct a global understanding of regulation, but also pave the way for discovery of compounds that target (ribo-)regulators to mitigate virulence and antibiotic resistance. The canonical relationship between a bacterial operon and the mRNA transcript produced from the operon has become significantly more complex as numerous regulatory mechanisms that impact the stability, translational efficiency, and early termination rates for mRNA transcripts have been described. With the rise of antibiotic resistance, these mechanisms offer new potential targets for antibiotic development. In this study we used a combination of high-throughput sequencing technologies to assess genome-wide transcription start and stop sites, as well as determine condition specific global transcription patterns in the human pathogen Streptococcus pneumoniae. We find that the majority of multi-gene operons have alternative start and stop sites enabling condition specific regulation of genes within the same operon. Furthermore, we identified many putative RNA regulators that are widespread in the S. pneumoniae pan-genome. Finally, we show that separately collected RNA-Seq data enables identification of conditional triggers for regulatory RNAs, and experimentally demonstrate that our approach may be used to identify drug-able RNA targets by establishing that pyrR RNA functionality is critical for successful S. pneumoniae mouse colonization and infection. Thus, our study not only uses genome-wide high-throughput approaches to identify putative RNA regulators, but also establishes the importance of such regulators in S. pneumoniae virulence.
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Affiliation(s)
- Indu Warrier
- Biology Department, Boston College, Chestnut Hill, Massachusetts, United States of America
| | - Nikhil Ram-Mohan
- Biology Department, Boston College, Chestnut Hill, Massachusetts, United States of America
| | - Zeyu Zhu
- Biology Department, Boston College, Chestnut Hill, Massachusetts, United States of America
| | - Ariana Hazery
- Biology Department, Boston College, Chestnut Hill, Massachusetts, United States of America
| | - Haley Echlin
- Department of Infectious Diseases, St Jude Children’s Research Hospital, Memphis, Tennessee, United States of America
| | - Jason Rosch
- Department of Infectious Diseases, St Jude Children’s Research Hospital, Memphis, Tennessee, United States of America
| | - Michelle M. Meyer
- Biology Department, Boston College, Chestnut Hill, Massachusetts, United States of America
- * E-mail: (MMM); (TvO)
| | - Tim van Opijnen
- Biology Department, Boston College, Chestnut Hill, Massachusetts, United States of America
- * E-mail: (MMM); (TvO)
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Papke RT, Corral P, Ram-Mohan N, de la Haba RR, Sánchez-Porro C, Makkay A, Ventosa A. Horizontal gene transfer, dispersal and haloarchaeal speciation. Life (Basel) 2015; 5:1405-26. [PMID: 25997110 PMCID: PMC4500145 DOI: 10.3390/life5021405] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2015] [Revised: 05/08/2015] [Accepted: 05/11/2015] [Indexed: 11/28/2022] Open
Abstract
The Halobacteria are a well-studied archaeal class and numerous investigations are showing how their diversity is distributed amongst genomes and geographic locations. Evidence indicates that recombination between species continuously facilitates the arrival of new genes, and within species, it is frequent enough to spread acquired genes amongst all individuals in the population. To create permanent independent diversity and generate new species, barriers to recombination are probably required. The data support an interpretation that rates of evolution (e.g., horizontal gene transfer and mutation) are faster at creating geographically localized variation than dispersal and invasion are at homogenizing genetic differences between locations. Therefore, we suggest that recurrent episodes of dispersal followed by variable periods of endemism break the homogenizing forces of intrapopulation recombination and that this process might be the principal stimulus leading to divergence and speciation in Halobacteria.
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Affiliation(s)
- R. Thane Papke
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT 06269, USA; E-Mails: (N.R.-M.); (A.M.)
- Author to whom correspondence should be addressed; E-Mail:
| | - Paulina Corral
- Department of Microbiology and Parasitology, University of Seville, 41004 Seville, Spain; E-Mails: (P.C.); (R.R.H.); (C.S.-P.); (A.V.)
| | - Nikhil Ram-Mohan
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT 06269, USA; E-Mails: (N.R.-M.); (A.M.)
| | - Rafael R. de la Haba
- Department of Microbiology and Parasitology, University of Seville, 41004 Seville, Spain; E-Mails: (P.C.); (R.R.H.); (C.S.-P.); (A.V.)
| | - Cristina Sánchez-Porro
- Department of Microbiology and Parasitology, University of Seville, 41004 Seville, Spain; E-Mails: (P.C.); (R.R.H.); (C.S.-P.); (A.V.)
| | - Andrea Makkay
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT 06269, USA; E-Mails: (N.R.-M.); (A.M.)
| | - Antonio Ventosa
- Department of Microbiology and Parasitology, University of Seville, 41004 Seville, Spain; E-Mails: (P.C.); (R.R.H.); (C.S.-P.); (A.V.)
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