Research advances from the National Institutes of Health (NIH) Intramural Research Program (IRP) are often published in high-impact journals. Read some of our recent articles:
Authors: Karron RA, Luongo C, Thumar B, Loehr KM, Englund JA, Collins PL, Buchholz UJ.
Journal: Sci Transl Med. 2015 Nov 4;7(312):312ra175. doi: 10.1126/scitranslmed.aac8463.
Respiratory syncytial virus (RSV) is the leading viral cause of severe pediatric respiratory illness, and a safe and effective vaccine for use in infancy and early childhood is needed. We previously showed that deletion of the coding sequence for the viral M2-2 protein (ΔM2-2) down-regulated viral RNA replication and up-regulated gene transcription and antigen synthesis, raising the possibility of development of an attenuated vaccine with enhanced immunogenicity. RSV MEDI ΔM2-2 was therefore evaluated as a live intranasal vaccine in adults, RSV-seropositive children, and RSV-seronegative children. When results in RSV-seronegative children were compared to those achieved with the previous leading live attenuated RSV candidate vaccine, vaccine virus shedding was significantly more restricted, yet the postvaccination RSV-neutralizing serum antibody achieved [geometric mean titer (GMT) = 1:97] was significantly greater. Surveillance during the subsequent RSV season showed that several seronegative RSV MEDI ΔM2-2 recipients had substantial antibody rises without reported illness, suggesting that the vaccine was protective yet primed for anamnestic responses to RSV. Rational design appears to have yielded a candidate RSV vaccine that is intrinsically superior at eliciting protective antibody in RSV-naïve children and highlights an approach for the development of live attenuated RSV vaccines.
Copyright © 2015, American Association for the Advancement of Science.
Authors: Brehm A, Liu Y, Sheikh A, Marrero B, Omoyinmi E, Zhou Q, Montealegre G, Biancotto A, Reinhardt A, Almeida de Jesus A, Pelletier M, Tsai WL, Remmers EF, Kardava L, Hill S, Kim H, Lachmann HJ, Megarbane A, Chae JJ, Brady J, Castillo RD, Brown D, Casano AV, Gao L, Chapelle D, Huang Y, Stone D, Chen Y, Sotzny F, Lee CC, Kastner DL, Torrelo A, Zlotogorski A, Moir S, Gadina M, McCoy P, Wesley R, Rother K, Hildebrand PW, Brogan P, Krüger E, Aksentijevich I, Goldbach-Mansky R.
Journal: J Clin Invest. 2015 Nov 2;125(11):4196-211. doi: 10.1172/JCI81260. Epub 2015 Oct 20.
Autosomal recessive mutations in proteasome subunit β 8 (PSMB8), which encodes the inducible proteasome subunit β5i, cause the immune-dysregulatory disease chronic atypical neutrophilic dermatosis with lipodystrophy and elevated temperature (CANDLE), which is classified as a proteasome-associated autoinflammatory syndrome (PRAAS). Here, we identified 8 mutations in 4 proteasome genes, PSMA3 (encodes α7), PSMB4 (encodes β7), PSMB9 (encodes β1i), and proteasome maturation protein (POMP), that have not been previously associated with disease and 1 mutation in PSMB8 that has not been previously reported. One patient was compound heterozygous for PSMB4 mutations, 6 patients from 4 families were heterozygous for a missense mutation in 1 inducible proteasome subunit and a mutation in a constitutive proteasome subunit, and 1 patient was heterozygous for a POMP mutation, thus establishing a digenic and autosomal dominant inheritance pattern of PRAAS. Function evaluation revealed that these mutations variably affect transcription, protein expression, protein folding, proteasome assembly, and, ultimately, proteasome activity. Moreover, defects in proteasome formation and function were recapitulated by siRNA-mediated knockdown of the respective subunits in primary fibroblasts from healthy individuals. Patient-isolated hematopoietic and nonhematopoietic cells exhibited a strong IFN gene-expression signature, irrespective of genotype. Additionally, chemical proteasome inhibition or progressive depletion of proteasome subunit gene transcription with siRNA induced transcription of type I IFN genes in healthy control cells. Our results provide further insight into CANDLE genetics and link global proteasome dysfunction to increased type I IFN production.
Authors: Fitzhugh CD, Hsieh MM, Allen D, Coles WA, Seamon C, Ring M, Zhao X, Minniti CP, Rodgers GP, Schechter AN, Tisdale JF, Taylor JG
Journal: PLoS One. 2015 Nov 17;10(11):e0141706. doi: 10.1371/journal.pone.0141706.
BACKGROUND: Adults with sickle cell anemia (HbSS) are inconsistently treated with hydroxyurea.
OBJECTIVES: We retrospectively evaluated the effects of elevating fetal hemoglobin with hydroxyurea on organ damage and survival in patients enrolled in our screening study between 2001 and 2010.
METHODS: An electronic medical record facilitated development of a database for comparison of study parameters based on hydroxyurea exposure and dose. This study is registered with ClinicalTrials.gov, number NCT00011648.
RESULTS: Three hundred eighty-three adults with homozygous sickle cell disease were analyzed with 59 deaths during study follow-up. Cox regression analysis revealed deceased subjects had more hepatic dysfunction (elevated alkaline phosphatase, Hazard Ratio = 1.005, 95% CI 1.003-1.006, p<0.0.0001), kidney dysfunction (elevated creatinine, Hazard Ratio = 1.13, 95% CI 1.00-1.27, p = 0.043), and cardiopulmonary dysfunction (elevated tricuspid jet velocity on echocardiogram, Hazard Ratio = 2.22, 1.23-4.02, p = 0.0082). Sixty-six percent of subjects were treated with hydroxyurea, although only 66% of those received a dose within the recommended therapeutic range. Hydroxyurea use was associated with improved survival (Hazard Ratio = 0.58, 95% CI 0.34-0.97, p = 0.040). This effect was most pronounced in those taking the recommended dose of 15-35 mg/kg/day (Hazard Ratio 0.36, 95% CI 0.17-0.73, p = 0.0050). Hydroxyurea use was not associated with changes in organ function over time. Further, subjects with higher fetal hemoglobin responses to hydroxyurea were more likely to survive (p = 0.0004). While alkaline phosphatase was lowest in patients with the best fetal hemoglobin response (95.4 versus 123.6, p = 0.0065 and 96.1 versus 113.6U/L, p = 0.041 at first and last visits, respectively), other markers of organ damage were not consistently improved over time in patients with the highest fetal hemoglobin levels.
CONCLUSIONS: Our data suggest that adults should be treated with the maximum tolerated hydroxyurea dose, ideally before organ damage occurs. Prospective studies are indicated to validate these findings.
Authors: Meisel C, Schulze-Bonhage A, Freestone D, Cook MJ, Achermann P, Plenz D.
Journal: Proc Natl Acad Sci U S A. 2015 Nov 9. pii: 201513716.
Pathological changes in excitability of cortical tissue commonly underlie the initiation and spread of seizure activity in patients suffering from epilepsy. Accordingly, monitoring excitability and controlling its degree using antiepileptic drugs (AEDs) is of prime importance for clinical care and treatment. To date, adequate measures of excitability and action of AEDs have been difficult to identify. Recent insights into ongoing cortical activity have identified global levels of phase synchronization as measures that characterize normal levels of excitability and quantify any deviation therefrom. Here, we explore the usefulness of these intrinsic measures to quantify cortical excitability in humans. First, we observe a correlation of such markers with stimulation-evoked responses suggesting them to be viable excitability measures based on ongoing activity. Second, we report a significant covariation with the level of AED load and a wake-dependent modulation. Our results indicate that excitability in epileptic networks is effectively reduced by AEDs and suggest the proposed markers as useful candidates to quantify excitability in routine clinical conditions overcoming the limitations of electrical or magnetic stimulation. The wake-dependent time course of these metrics suggests a homeostatic role of sleep, to rebalance cortical excitability.
Authors: Palazzo E, Kellett M, Cataisson C, Gormley A, Bible PW, Pietroni V, Radoja N, Hwang J, Blumenberg M, Yuspa SH, Morasso MI.
Journal: Oncogene. 2015 Nov 2. doi: 10.1038/onc.2015.380.
Epidermal homeostasis depends on the coordinated control of keratinocyte cell cycle. Differentiation and the alteration of this balance can result in neoplastic development. Here we report on a novel DLX3-dependent network that constrains epidermal hyperplasia and squamous tumorigenesis. By integrating genetic and transcriptomic approaches, we demonstrate that DLX3 operates through a p53-regulated network. DLX3 and p53 physically interact on the p21 promoter to enhance p21 expression. Elevating DLX3 in keratinocytes produces a G1-S blockade associated with p53 signature transcriptional profiles. In contrast, DLX3 loss promotes a mitogenic phenotype associated with constitutive activation of ERK. DLX3 expression is lost in human skin cancers and is extinguished during progression of experimentally induced mouse squamous cell carcinoma (SCC). Reinstatement of DLX3 function is sufficient to attenuate the migration of SCC cells, leading to decreased wound closure. Our data establish the DLX3-p53 interplay as a major regulatory axis in epidermal differentiation and suggest that DLX3 is a modulator of skin carcinogenesis. Oncogene advance online publication, 2 November 2015; doi:10.1038/onc.2015.380.
Author: Grayson PC, Kaplan MJ
Journal: J Leukoc Biol. 2015 Oct 2. pii: jlb.5BT0615-247R.
The putative role of neutrophils in host defense against pathogens is a well-recognized aspect of neutrophil function. The discovery of neutrophil extracellular traps has expanded the known range of neutrophil defense mechanisms and catalyzed a discipline of research focused upon ways in which neutrophils can shape the immunologic landscape of certain autoimmune diseases, including systemic lupus erythematosus. Enhanced neutrophil extracellular trap formation and impaired neutrophil extracellular trap clearance may contribute to immunogenicity in systemic lupus erythematosus and other autoimmune diseases by promoting the externalization of modified autoantigens, inducing synthesis of type I IFNs, stimulating the inflammasome, and activating both the classic and alternative pathways of the complement system. Vasculopathy is a central feature of many autoimmune diseases, and neutrophil extracellular traps may contribute directly to endothelial cell dysfunction, atherosclerotic plaque burden, and thrombosis. The elucidation of the subcellular events of neutrophil extracellular trap formation may generate novel, therapeutic strategies that target the innate immune system in autoimmune and vascular diseases.
Authors: Freudenthal BD, Beard WA, Cuneo MJ, Dyrkheeva NS, Wilson SH
Journal: Nat Struct Mol Biol. 2015 Oct 12. doi: 10.1038/nsmb.3105. [Epub ahead of print]
DNA apurinic-apyrimidinic (AP) sites are prevalent noncoding threats to genomic stability and are processed by AP endonuclease 1 (APE1). APE1 incises the AP-site phosphodiester backbone, generating a DNA-repair intermediate that is potentially cytotoxic. The molecular events of the incision reaction remain elusive, owing in part to limited structural information. We report multiple high-resolution human APE1-DNA structures that divulge new features of the APE1 reaction, including the metal-binding site, the nucleophile and the arginine clamps that mediate product release. We also report APE1-DNA structures with a T-G mismatch 5' to the AP site, representing a clustered lesion occurring in methylated CpG dinucleotides. These structures reveal that APE1 molds the T-G mismatch into a unique Watson-Crick-like geometry that distorts the active site, thus reducing incision. These snapshots provide mechanistic clarity for APE1 while affording a rational framework to manipulate biological responses to DNA damage.
Authors: Alberstein R, Grey R, Zimmet A, Simmons DK, Mayer ML.
Journal: Proc Natl Acad Sci U S A. 2015 Oct 12. pii: 201513771. [Epub ahead of print]
Recent genome projects for ctenophores have revealed the presence of numerous ionotropic glutamate receptors (iGluRs) in Mnemiopsis leidyi and Pleurobrachia bachei, among our earliest metazoan ancestors. Sequence alignments and phylogenetic analysis show that these form a distinct clade from the well-characterized AMPA, kainate, and NMDA iGluR subtypes found in vertebrates. Although annotated as glutamate and kainate receptors, crystal structures of the ML032222a and PbiGluR3 ligand-binding domains (LBDs) reveal endogenous glycine in the binding pocket, whereas ligand-binding assays show that glycine binds with nanomolar affinity; biochemical assays and structural analysis establish that glutamate is occluded from the binding cavity. Further analysis reveals ctenophore-specific features, such as an interdomain Arg-Glu salt bridge, present only in subunits that bind glycine, but also a conserved disulfide in loop 1 of the LBD that is found in all vertebrate NMDA but not AMPA or kainate receptors. We hypothesize that ctenophore iGluRs are related to an early ancestor of NMDA receptors, suggesting a common evolutionary path for ctenophores and bilaterian species, and suggest that future work should consider both glycine and glutamate as candidate neurotransmitters in ctenophore species.
Authors: Tiniakou E, Mammen AL.
Journal: Clin Rev Allergy Immunol. 2015 Oct 1. [Epub ahead of print]
The idiopathic inflammatory myopathies (IIMs) are a heterogeneous group of autoimmune diseases (collectively known as myositis) affecting the skeletal muscles as well as other organ systems such as skin, lungs, and joints. The primary forms of myositis include polymyositis (PM), dermatomyositis (PM), and immune-mediated necrotizing myopathy (IMNM). Patients with these diseases experience progressive proximal muscle weakness, have characteristic muscle biopsy findings, and produce autoantibodies that are associated with unique clinical features. One distinguishing feature of these patients is that they are also known to have an increased risk of cancer. Since the first description of the association in 1916, it has been extensively reported in the medical literature. However, there have been significant variations between the different studies with regard to the degree of cancer risk in patients with IIM. These discrepancies can, in part, be attributed to differences in the definition of malignancy-associated myositis used in different studies. In recent years, significant advances have been made in defining specific features of IIM that are associated with the development of malignancy. One of these has been myositis-specific antibodies (MSAs), which are linked to distinct clinical phenotypes and categorize patients into groups with more homogeneous features. Indeed, patients with certain MSAs seem to be at particularly increased risk of malignancy. This review attempts a systematic evaluation of research regarding the association between malignancy and myositis.
Authors: Wasko MC, Dasgupta A, Ilse Sears G, Fries JF, Ward MM.
Journal: Arthritis Care Res (Hoboken). 2015 Sep 28. doi: 10.1002/acr.22722.
OBJECTIVE: Medications for rheumatoid arthritis (RA) may affect survival. However, studies often include limited follow-up and do not account for selection bias in treatment allocation. Using a large longitudinal database, we examined the association between prednisone use and mortality in RA, and whether this risk was modified with concomitant disease-modifying antirheumatic drug (DMARD) use, after controlling for propensity for treatment with prednisone and individual DMARDs.
METHODS: In a prospective study of 5,626 patients with RA followed for up to 25 years, we determined the risk of death associated with prednisone use alone and combined treatment of prednisone with methotrexate or sulfasalazine. We used the random forest method to generate propensity scores for prednisone use and each DMARD at study entry and during follow-up. Mortality risks were estimated using multivariate Cox models that included propensity scores.
RESULTS: During follow-up (median 4.97 years), 666 patients (11.8%) died. In a multivariate, propensity-adjusted model, prednisone use was associated with an increased risk of death (HR 2.83 [95% CI 1.03, 7.76]). However, there was a significant interaction between prednisone use and methotrexate use (p=0.03), so that risk was attenuated when patients were treated with both medications (HR 0.99 [95% CI 0.18, 5.36]). However, combination treatment also weakened the protective association of methotrexate with mortality. Results were similar for sulfasalazine.
CONCLUSION: Prednisone use was associated with a significantly increased risk of mortality in patients with RA. This association was mitigated by concomitant DMARD use, but combined treatment also negated the previously reported beneficial association of methotrexate with survival in RA. This article is protected by copyright. All rights reserved.