Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 47
Filter
2.
Nat Commun ; 13(1): 4057, 2022 07 26.
Article in English | MEDLINE | ID: mdl-35882841

ABSTRACT

While many genetic diseases have effective treatments, they frequently progress rapidly to severe morbidity or mortality if those treatments are not implemented immediately. Since front-line physicians frequently lack familiarity with these diseases, timely molecular diagnosis may not improve outcomes. Herein we describe Genome-to-Treatment, an automated, virtual system for genetic disease diagnosis and acute management guidance. Diagnosis is achieved in 13.5 h by expedited whole genome sequencing, with superior analytic performance for structural and copy number variants. An expert panel adjudicated the indications, contraindications, efficacy, and evidence-of-efficacy of 9911 drug, device, dietary, and surgical interventions for 563 severe, childhood, genetic diseases. The 421 (75%) diseases and 1527 (15%) effective interventions retained are integrated with 13 genetic disease information resources and appended to diagnostic reports ( https://gtrx.radygenomiclab.com ). This system provided correct diagnoses in four retrospectively and two prospectively tested infants. The Genome-to-Treatment system facilitates optimal outcomes in children with rapidly progressive genetic diseases.


Subject(s)
DNA Copy Number Variations , Child , Humans , Infant , Retrospective Studies , Whole Genome Sequencing
3.
Nat Genet ; 54(8): 1214-1226, 2022 08.
Article in English | MEDLINE | ID: mdl-35864190

ABSTRACT

Cirrhosis is usually a late-onset and life-threatening disease characterized by fibrotic scarring and inflammation that disrupts liver architecture and function. While it is typically the result of alcoholism or hepatitis viral infection in adults, its etiology in infants is much less understood. In this study, we report 14 children from ten unrelated families presenting with a syndromic form of pediatric liver cirrhosis. By genome/exome sequencing, we found recessive variants in FOCAD segregating with the disease. Zebrafish lacking focad phenocopied the human disease, revealing a signature of altered messenger RNA (mRNA) degradation processes in the liver. Using patient's primary cells and CRISPR-Cas9-mediated inactivation in human hepatic cell lines, we found that FOCAD deficiency compromises the SKI mRNA surveillance pathway by reducing the levels of the RNA helicase SKIC2 and its cofactor SKIC3. FOCAD knockout hepatocytes exhibited lowered albumin expression and signs of persistent injury accompanied by CCL2 overproduction. Our results reveal the importance of FOCAD in maintaining liver homeostasis and disclose a possible therapeutic intervention point via inhibition of the CCL2/CCR2 signaling axis.


Subject(s)
Liver Cirrhosis , Tumor Suppressor Proteins , Adult , Animals , Child , Hepatocytes/metabolism , Humans , Liver/metabolism , Liver Cirrhosis/genetics , Liver Cirrhosis/metabolism , RNA, Messenger/genetics , RNA, Messenger/metabolism , Syndrome , Tumor Suppressor Proteins/genetics , Zebrafish/genetics
4.
BMC Infect Dis ; 22(1): 404, 2022 Apr 25.
Article in English | MEDLINE | ID: mdl-35468749

ABSTRACT

BACKGROUND: The Centers for Disease Control and Prevention contracted with laboratories to sequence the SARS-CoV-2 genome from positive samples across the United States to enable public health officials to investigate the impact of variants on disease severity as well as the effectiveness of vaccines and treatment. Herein we present the initial results correlating RT-PCR quality control metrics with sample collection and sequencing methods from full SARS-CoV-2 viral genomic sequencing of 24,441 positive patient samples between April and June 2021. METHODS: RT-PCR confirmed (N Gene Ct value < 30) positive patient samples, with nucleic acid extracted from saliva, nasopharyngeal and oropharyngeal swabs were selected for viral whole genome SARS-CoV-2 sequencing. Sequencing was performed using Illumina COVIDSeq™ protocol on either the NextSeq550 or NovaSeq6000 systems. Informatic variant calling, and lineage analysis were performed using DRAGEN COVID Lineage applications on Illumina's Basespace cloud analytical system. All sequence data and variant calls were uploaded to NCBI and GISAID. RESULTS: An association was observed between higher sequencing coverage, quality, and samples with a lower Ct value, with < 27 being optimal, across both sequencing platforms and sample collection methods. Both nasopharyngeal swabs and saliva samples were found to be optimal samples of choice for SARS-CoV-2 surveillance sequencing studies, both in terms of strain identification and sequencing depth of coverage, with NovaSeq 6000 providing higher coverage than the NextSeq 550. The most frequent variants identified were the B.1.617.2 Delta (India) and P.1 Gamma (Brazil) variants in the samples sequenced between April 2021 and June 2021. At the time of submission, the most common variant > 99% of positives sequenced was Omicron. CONCLUSION: These initial analyses highlight the importance of sequencing platform, sample collection methods, and RT-PCR Ct values in guiding surveillance efforts. These surveillance studies evaluating genetic changes of SARS-CoV-2 have been identified as critical by the CDC that can affect many aspects of public health including transmission, disease severity, diagnostics, therapeutics, and vaccines.


Subject(s)
COVID-19 , SARS-CoV-2 , COVID-19/diagnosis , COVID-19/epidemiology , COVID-19/prevention & control , Centers for Disease Control and Prevention, U.S. , Genomics , Humans , SARS-CoV-2/genetics , United States/epidemiology
6.
Mol Genet Genomic Med ; 9(7): e1623, 2021 07.
Article in English | MEDLINE | ID: mdl-34076366

ABSTRACT

BACKGROUND: Cockayne syndrome (CS) is a rare autosomal recessive disorder characterized by growth failure and multisystemic degeneration. Excision repair cross-complementation group 6 (ERCC6 OMIM: *609413) is the gene most frequently mutated in CS. METHODS: A child with pre and postnatal growth failure and progressive neurologic deterioration with multisystem involvement, and with nondiagnostic whole-exome sequencing, was screened for causal variants with whole-genome sequencing (WGS). RESULTS: WGS identified biallelic ERCC6 variants, including a previously unreported intronic variant. Pathogenicity of these variants was established by demonstrating reduced levels of ERCC6 mRNA and protein expression, normal unscheduled DNA synthesis, and impaired recovery of RNA synthesis in patient fibroblasts following UV-irradiation. CONCLUSION: The study confirms the pathogenicity of a previously undescribed upstream intronic variant, highlighting the power of genome sequencing to identify noncoding variants. In addition, this report provides evidence for the utility of a combination approach of genome sequencing plus functional studies to provide diagnosis in a child for whom a lengthy diagnostic odyssey, including exome sequencing, was previously unrevealing.


Subject(s)
Cockayne Syndrome/genetics , DNA Helicases/genetics , DNA Repair Enzymes/genetics , Introns , Poly-ADP-Ribose Binding Proteins/genetics , Whole Genome Sequencing/methods , Cells, Cultured , Child , Cockayne Syndrome/diagnosis , Female , Fibroblasts/metabolism , Humans
9.
NPJ Genom Med ; 6(1): 29, 2021 Apr 22.
Article in English | MEDLINE | ID: mdl-33888711

ABSTRACT

Congenital heart disease (CHD) is the most common congenital anomaly and a major cause of infant morbidity and mortality. While morbidity and mortality are highest in infants with underlying genetic conditions, molecular diagnoses are ascertained in only ~20% of cases using widely adopted genetic tests. Furthermore, cost of care for children and adults with CHD has increased dramatically. Rapid whole genome sequencing (rWGS) of newborns in intensive care units with suspected genetic diseases has been associated with increased rate of diagnosis and a net reduction in cost of care. In this study, we explored whether the clinical utility of rWGS extends to critically ill infants with structural CHD through a retrospective review of rWGS study data obtained from inpatient infants < 1 year with structural CHD at a regional children's hospital. rWGS diagnosed genetic disease in 46% of the enrolled infants. Moreover, genetic disease was identified five times more frequently with rWGS than microarray ± gene panel testing in 21 of these infants (rWGS diagnosed 43% versus 10% with microarray ± gene panels, p = 0.02). Molecular diagnoses ranged from syndromes affecting multiple organ systems to disorders limited to the cardiovascular system. The average daily hospital spending was lower in the time period post blood collection for rWGS compared to prior (p = 0.003) and further decreased after rWGS results (p = 0.000). The cost was not prohibitive to rWGS implementation in the care of this cohort of infants. rWGS provided timely actionable information that impacted care and there was evidence of decreased hospital spending around rWGS implementation.

10.
Cancer Res ; 80(23): 5393-5407, 2020 12 01.
Article in English | MEDLINE | ID: mdl-33046443

ABSTRACT

Medulloblastoma is among the most common malignant brain tumors in children. Recent studies have identified at least four subgroups of the disease that differ in terms of molecular characteristics and patient outcomes. Despite this heterogeneity, most patients with medulloblastoma receive similar therapies, including surgery, radiation, and intensive chemotherapy. Although these treatments prolong survival, many patients still die from the disease and survivors suffer severe long-term side effects from therapy. We hypothesize that each patient with medulloblastoma is sensitive to different therapies and that tailoring therapy based on the molecular and cellular characteristics of patients' tumors will improve outcomes. To test this, we assembled a panel of orthotopic patient-derived xenografts (PDX) and subjected them to DNA sequencing, gene expression profiling, and high-throughput drug screening. Analysis of DNA sequencing revealed that most medulloblastomas do not have actionable mutations that point to effective therapies. In contrast, gene expression and drug response data provided valuable information about potential therapies for every tumor. For example, drug screening demonstrated that actinomycin D, which is used for treatment of sarcoma but rarely for medulloblastoma, was active against PDXs representing Group 3 medulloblastoma, the most aggressive form of the disease. Functional analysis of tumor cells was successfully used in a clinical setting to identify more treatment options than sequencing alone. These studies suggest that it should be possible to move away from a one-size-fits-all approach and begin to treat each patient with therapies that are effective against their specific tumor. SIGNIFICANCE: These findings show that high-throughput drug screening identifies therapies for medulloblastoma that cannot be predicted by genomic or transcriptomic analysis.


Subject(s)
Antineoplastic Agents/pharmacology , Cerebellar Neoplasms/drug therapy , Medulloblastoma/drug therapy , Precision Medicine/methods , Animals , Cell Line, Tumor , Cerebellar Neoplasms/genetics , Child , Dactinomycin/pharmacology , Gene Expression Regulation, Neoplastic , High-Throughput Screening Assays , Humans , Male , Medulloblastoma/genetics , Mice, Inbred NOD , Mutation , Polymorphism, Single Nucleotide , Exome Sequencing , Xenograft Model Antitumor Assays
11.
Materials (Basel) ; 13(13)2020 Jul 07.
Article in English | MEDLINE | ID: mdl-32645924

ABSTRACT

The range of selective laser sintering (SLS) materials is currently limited, and the available materials are often of high cost. Moreover, the mechanical strength of wood-plastic SLS parts is low, which restricts the application of a SLS technology. A new composite material has been proposed to address these issues, while simultaneously valorizing agricultural and forestry waste. This composite presents several advantages, including reduced pollution associated with waste disposal and reduced CO2 emission with the SLS process in addition to good mechanical strength. In this article, a novel and low-cost Prosopis chilensis/polyethersulfone composite (PCPC) was used as a primary material for SLS. The formability of PCPC with various raw material ratios was investigated via single-layer experiments, while the mechanical properties and dimensional accuracy of the parts produced using the various PCPC ratios were evaluated. Further, the microstructure and particle distribution in the PCPC pieces were examined using scanning electron microscopy. The result showed that the SLS part produced via 10/90 (wt/wt) PCPC exhibited the best mechanical strength and forming quality compared to other ratios and pure polyethersulfone (PES), where bending and tensile strengths of 10.78 and 4.94 MPa were measured. To improve the mechanical strength, post-processing infiltration was used and the PCPC-waxed parts were enhanced to 12.38 MPa and 5.73 MPa for bending and tensile strength.

12.
Pediatr Crit Care Med ; 20(11): 1007-1020, 2019 11.
Article in English | MEDLINE | ID: mdl-31246743

ABSTRACT

OBJECTIVES: Genetic disorders are a leading contributor to mortality in the neonatal ICU and PICU in the United States. Although individually rare, there are over 6,200 single-gene diseases, which may preclude a genetic diagnosis prior to ICU admission. Rapid whole genome sequencing is an emerging method of diagnosing genetic conditions in time to affect ICU management of neonates; however, its clinical utility has yet to be adequately demonstrated in critically ill children. This study evaluates next-generation sequencing in pediatric critical care. DESIGN: Retrospective cohort study. SETTING: Single-center PICU in a tertiary children's hospital. PATIENTS: Children 4 months to 18 years admitted to the PICU who were nominated between July 2016 and May 2018. INTERVENTIONS: Rapid whole genome sequencing with targeted phenotype-driven analysis was performed on patients and their parents, when parental samples were available. MEASUREMENTS AND MAIN RESULTS: A molecular diagnosis was made by rapid whole genome sequencing in 17 of 38 children (45%). In four of the 17 patients (24%), the genetic diagnoses led to a change in management while in the PICU, including genome-informed changes in pharmacotherapy and transition to palliative care. Nine of the 17 diagnosed children (53%) had no dysmorphic features or developmental delay. Eighty-two percent of diagnoses affected the clinical management of the patient and/or family after PICU discharge, including avoidance of biopsy, administration of factor replacement, and surveillance for disorder-related sequelae. CONCLUSIONS: This study demonstrates a retrospective evaluation for undiagnosed genetic disease in the PICU and clinical utility of rapid whole genome sequencing in a portion of critically ill children. Further studies are needed to identify PICU patients who will benefit from rapid whole genome sequencing early in PICU admission when the underlying etiology is unclear.


Subject(s)
Genetic Diseases, Inborn/diagnosis , Whole Genome Sequencing , Adolescent , Child , Child, Preschool , Critical Illness/therapy , Female , Humans , Infant , Intensive Care Units, Pediatric/statistics & numerical data , Male , Precision Medicine/methods , Retrospective Studies
13.
Article in English | MEDLINE | ID: mdl-29549119

ABSTRACT

Congenital diaphragmatic hernia (CDH) results from incomplete formation of the diaphragm leading to herniation of abdominal organs into the thoracic cavity. CDH is associated with pulmonary hypoplasia, congenital heart disease, and pulmonary hypertension. Genetically, it is associated with aneuploidies, chromosomal copy-number variants, and single gene mutations. CDH is the most expensive noncardiac congenital defect. Management frequently requires implementation of extracorporeal membrane oxygenation (ECMO), which increases management expenditures 2.4-3.5-fold. The cost of management of CDH has been estimated to exceed $250 million per year. Despite in-hospital survival of 80%-90%, current management is imperfect, as a great proportion of surviving children have long-term functional deficits. We report the case of a premature infant prenatally diagnosed with CDH and congenital heart disease, who had a protracted and complicated course in the intensive care unit with multiple surgical interventions, including postcardiac surgery ECMO, gastrostomy tube placement with Nissen fundoplication, tracheostomy for respiratory failure, recurrent infections, and developmental delay. Rapid whole-genome sequencing (rWGS) identified a de novo, likely pathogenic, c.3096_ 3100delCAAAG (p.Lys1033Argfs*32) variant in ARID1B, providing a diagnosis of Coffin-Siris syndrome. Her parents elected palliative care and she died later that day.


Subject(s)
Abnormalities, Multiple/diagnosis , Abnormalities, Multiple/genetics , Critical Illness , Face/abnormalities , Hand Deformities, Congenital/diagnosis , Hand Deformities, Congenital/genetics , Intellectual Disability/diagnosis , Intellectual Disability/genetics , Micrognathism/diagnosis , Micrognathism/genetics , Neck/abnormalities , Phenotype , Whole Genome Sequencing , Abnormalities, Multiple/therapy , Delayed Diagnosis , Disease Management , Female , Genome-Wide Association Study , Genomics/methods , Hand Deformities, Congenital/therapy , Heart Defects, Congenital , Hernias, Diaphragmatic, Congenital , Humans , Infant , Infections , Intellectual Disability/therapy , Micrognathism/therapy
14.
Article in English | MEDLINE | ID: mdl-28864462

ABSTRACT

A 9-mo-old infant was admitted with infantile spasms that improved on administration of topiramate and steroids. He also had developmental delay, esotropia, and hypsarrhythmia on interictal electroencephalogram (EEG), and normal brain magnetic resonance imaging (MRI). West syndrome is the triad of infantile spasms, interictal hypsarrhythmia, and mental retardation. Rapid trio whole-genome sequencing (WGS) revealed a novel, likely pathogenic, de novo variant in the gene encoding γ-aminobutyric acid (GABA) type A receptor, α1 polypeptide (GABRA1 c.789G>A, p.Met263Ile) in the proband. GABRA1 mutations have been associated with early infantile epileptic encephalopathy type 19 (EIEE19). We suggest that GABRA1 p.Met263Ile is associated with a distinct West syndrome phenotype.


Subject(s)
Receptors, GABA-A/genetics , Spasms, Infantile/genetics , Brain/cytology , Brain/metabolism , Developmental Disabilities/complications , Developmental Disabilities/genetics , Electroencephalography , Genome/genetics , High-Throughput Nucleotide Sequencing/methods , Humans , Infant , Intellectual Disability/complications , Intellectual Disability/genetics , Magnetic Resonance Imaging , Male , Mutation , Receptors, GABA-A/metabolism , Spasms, Infantile/complications , Spasms, Infantile/metabolism , gamma-Aminobutyric Acid/genetics
15.
Blood ; 126(21): 2355-61, 2015 Nov 19.
Article in English | MEDLINE | ID: mdl-26429975

ABSTRACT

Establishing a diagnosis in patients suspected of having a myelodysplastic syndrome (MDS) can be challenging and could be informed by the identification of somatic mutations. We performed a prospective study to examine the frequency and types of mutations encountered in 144 patients with unexplained cytopenias. Based on bone marrow findings, 17% were diagnosed with MDS, 15% with idiopathic cytopenias of undetermined significance (ICUS) and some evidence of dysplasia, and 69% with ICUS and no dysplasia. Bone marrow DNA was sequenced for mutations in 22 frequently mutated myeloid malignancy genes. Somatic mutations were identified in 71% of MDS patients, 62% of patients with ICUS and some dysplasia, and 20% of ICUS patients and no dysplasia. In total, 35% of ICUS patients carried a somatic mutation or chromosomal abnormality indicative of clonal hematopoiesis. We validated these results in a cohort of 91 lower-risk MDS and 249 ICUS cases identified over a 6-month interval. Mutations were found in 79% of those with MDS, in 45% of those with ICUS with dysplasia, and in 17% of those with ICUS without dysplasia. The spectrum of mutated genes was similar with the exception of SF3B1 which was rarely mutated in patients without dysplasia. Variant allele fractions were comparable between clonal ICUS (CCUS) and MDS as were mean age and blood counts. We demonstrate that CCUS is a more frequent diagnosis than MDS in cytopenic patients. Clinical and mutational features are similar in these groups and may have diagnostic utility once outcomes in CCUS patients are better understood.


Subject(s)
Alleles , Chromosome Aberrations , Gene Frequency , Hematopoiesis/genetics , Mutation , Myelodysplastic Syndromes , Age Factors , Female , Humans , Male , Myelodysplastic Syndromes/genetics , Myelodysplastic Syndromes/metabolism , Myelodysplastic Syndromes/pathology , Prospective Studies , Retrospective Studies
16.
Afr Health Sci ; 14(3): 663-71, 2014 Sep.
Article in English | MEDLINE | ID: mdl-25352886

ABSTRACT

BACKGROUND: Immigrants to developed countries are a major source of TB. Therefore amongst strategies adopted for TB control in developed countries include; 1) Screening immigrants at ports of entry referred to as "Port of Arrival Screening" (PoA) and 2) Passive screening (PS) for TB which means screening immigrants through general practices, hospitals, chest-clinics and emergency departments. Evidence of the effectiveness and cost effectiveness of these strategies is not consistent. OBJECTIVE: Evaluate efficiency of active PoA TB screening for immigrants from TB endemic-regions compared with Passive Screening of immigrant-populations from TB endemic-regions. METHODS: Major electronic-databases and reference lists of relevant studies were searched. Experts of immigrants' TB screening were contacted for additional studies published or unpublished. Systematic search of major databases identified only retrospective cohort-studies. Their qualities were assessed using Scottish Intercollegiate Guidelines Network (SIGN) methodological checklist for comparative cohort-studies. RESULTS: Systematic electronic searches identified 1443 citations. Of these 74 studies were retrieved for evaluation against the review's inclusion/exclusion criteria (see study inclusion/exclusion criteria). Four studies met the inclusion criteria (figure 2) which were low in the evidence hierarchy of primary effectiveness studies and had heterogeneities between them. Thus descriptive data-synthesis was performed. Proportionately PoA screening had the lowest percentage of receipt of tuberculin skin test (TST) and the highest percentage of non-attendance for TST reading (table 2). Active PoA screening reduced infectiousness by 34% compared to 30% by passive screening and new entrants screened at PoA were 80% less likely to be hospitalised Odds ratio (OR) = 0.2 (95% confidence interval (CI) 0.1 - 0.2). [Table: see text]. ECONOMIC ANALYSIS: One cost effectiveness analysis was found that compared the costs of; active PoA screening, general practice screening and homeless screening groups. The cost of detecting a case of TB were; £1.26, £13.17 and £96.36 for PS, homeless screening and active PoA screening respectively. The cost of preventing a case of TB were; £6.32, £23.00 and £10.00 for PS, homeless screening and PoA screening respectively, showing there is little difference between the different strategies. CONCLUSION: Active PoA screening is worth doing with significant benefits including early identification of risk groups with possible timely treatment/chemoprophylaxis intervention, prevention of transmission by significantly reducing infectiousness with subsequent avoidance of hospitalisation in active PoA screening group.


Subject(s)
Emigrants and Immigrants/statistics & numerical data , Mass Screening/economics , Tuberculin Test/economics , Tuberculosis, Pulmonary/diagnosis , Tuberculosis, Pulmonary/economics , Cost-Benefit Analysis , Emigration and Immigration , Humans , Mass Screening/methods , Prevalence , Retrospective Studies , Tuberculosis, Pulmonary/epidemiology
17.
East Mediterr Health J ; 19 Suppl 3: S184-9, 2014 Jan 09.
Article in English | MEDLINE | ID: mdl-24995744

ABSTRACT

The objective of this study was to determine the outcome of patients treated with recombinant activated factor VII (rFVIIa) to promote haemostasis in intractable bleeding associated with trauma injury or other causes. The medical records of 44 consecutive patients treated with rFVIIa were retrospectively reviewed for blood product use before and after treatment. A statistically significant decrease in blood product transfusion was evident in 23 trauma patients and 21 patients with other causes of bleeding who survived more than 4 hours after rFVIIa infusion. Although 10/23 trauma patients and 12/21 other causes patients died, between 2 and 50 days after rFVIIa infusion, these deaths were due to causes other than haemorrhage. The early use of rFVIIa was associated with decreased 50-day mortality in patients with severe trauma requiring massive transfusion, but was not associated with increased risk of severe thrombotic events.

18.
PLoS Genet ; 9(5): e1003505, 2013 May.
Article in English | MEDLINE | ID: mdl-23696749

ABSTRACT

ATM plays a critical role in cellular responses to DNA double-strand breaks (DSBs). We describe a new ATM-mediated DSB-induced DNA damage response pathway involving microRNA (miRNA): irradiation (IR)-induced DSBs activate ATM, which leads to the downregulation of miR-335, a miRNA that targets CtIP, which is an important trigger of DNA end resection in homologous recombination repair (HRR). We demonstrate that CREB is responsible for a large portion of miR-335 expression by binding to the promoter region of miR-335. CREB binding is greatly reduced after IR, corroborating with previous studies that IR-activated ATM phosphorylates CREB to reduce its transcription activity. Overexpression of miR-335 in HeLa cells resulted in reduced CtIP levels and post-IR colony survival and BRCA1 foci formation. Further, in two patient-derived lymphoblastoid cell lines with decreased post-IR colony survival, a "radiosensitive" phenotype, we demonstrated elevated miR-335 expression, reduced CtIP levels, and reduced BRCA1 foci formation. Colony survival, BRCA1 foci, and CtIP levels were partially rescued by miRNA antisense AMO-miR-335 treatment. Taken together, these findings strongly suggest that an ATM-dependent CREB-miR-335-CtIP axis influences the selection of HRR for repair of certain DSB lesions.


Subject(s)
Carrier Proteins/genetics , Cell Cycle Proteins/genetics , DNA-Binding Proteins/genetics , MicroRNAs/genetics , Nuclear Proteins/genetics , Protein Serine-Threonine Kinases/genetics , Recombinational DNA Repair/genetics , Tumor Suppressor Proteins/genetics , Ataxia Telangiectasia Mutated Proteins , BRCA1 Protein/genetics , Cell Cycle Proteins/metabolism , DNA Breaks, Double-Stranded/drug effects , DNA Damage/radiation effects , DNA Repair/radiation effects , DNA-Binding Proteins/metabolism , Down-Regulation/radiation effects , Endodeoxyribonucleases , Gene Expression/radiation effects , HeLa Cells , Humans , MicroRNAs/metabolism , Protein Serine-Threonine Kinases/metabolism , Recombinational DNA Repair/radiation effects , Tumor Suppressor Proteins/metabolism
19.
Radiat Res ; 177(2): 176-86, 2012 Feb.
Article in English | MEDLINE | ID: mdl-21962002

ABSTRACT

In an effort to explore the possible causes of human radiosensitivity and identify more rapid assays for cellular radiosensitivity, we interrogated a set of assays that evaluate cellular functions involved in recognition and repair of DNA double-strand breaks: (1) neutral comet assay, (2) radiation-induced γ-H2AX focus formation, (3) the temporal kinetics of structural maintenance of chromosomes 1 phosphorylation, (4) intra-S-phase checkpoint integrity, and (5) mitochondrial respiration. We characterized a unique panel of 19 "radiosensitive" human lymphoblastoid cell lines from individuals with undiagnosed diseases suggestive of a DNA repair disorder. Radiosensitivity was defined by reduced cellular survival using a clonogenic survival assay. Each assay identified cell lines with defects in DNA damage response functions. The highest concordance rate observed, 89% (17/19), was between an abnormal neutral comet assay and reduced survival by the colony survival assay. Our data also suggested that the neutral comet assay would be a more rapid surrogate for analyzing DNA repair/processing disorders.


Subject(s)
Biological Assay/methods , Cell Line/physiology , Cell Line/radiation effects , Colony-Forming Units Assay/methods , Comet Assay/methods , DNA Damage , Radiation Tolerance/physiology , Dose-Response Relationship, Radiation , Humans , Radiation Dosage
20.
Arthritis Rheum ; 64(2): 568-78, 2012 Feb.
Article in English | MEDLINE | ID: mdl-21905016

ABSTRACT

OBJECTIVE: Previous reports of cells from patients with systemic lupus erythematosus (SLE) note that repair of single-strand breaks is delayed, and these lesions may be converted to double-strand breaks (DSBs) at DNA replication forks. We undertook this study to assess the integrity of DSB recognition, signaling, and repair mechanisms in B lymphoblastoid cell lines derived from patients with pediatric SLE. METHODS: Nine assays were used to interrogate DSB repair and recognition in lymphoblastoid cell lines from patients with pediatric SLE, including the neutral comet assay (NCA), colony survival assay (CSA), irradiation-induced foci formation for γ-H2AX and 53BP1 proteins, kinetics of phosphorylation of structural maintenance of chromosomes protein 1 (SMC1), postirradiation bromodeoxyuridine incorporation to evaluate S phase checkpoint integrity, monoubiquitination of Fanconi protein D2, ATM protein expression, and non-homologous DNA end joining protein expression and function. RESULTS: Three of the 9 assays revealed abnormal patterns of response to irradiation-induced DNA damage. The NCA and CSA yielded aberrant results in the majority of SLE lymphoblastoid cell lines. Abnormal prolongation of SMC1 phosphorylation was also noted in 2 of 16 SLE lymphoblastoid cell lines. CONCLUSION: Our data suggest that DSB repair is defective in some lymphoblastoid cell lines from pediatric patients with SLE, especially when assessed by both NCA and CSA. Since these studies are nonspecific, further studies of DNA repair and kinetics are indicated to further delineate the underlying pathogenesis of SLE and possibly identify therapeutic targets.


Subject(s)
DNA Breaks, Double-Stranded , DNA Repair , Lupus Erythematosus, Systemic/genetics , Adolescent , Cell Line , Child , Female , Humans , Male , S Phase Cell Cycle Checkpoints , Young Adult
SELECTION OF CITATIONS
SEARCH DETAIL
...