Authors: Bauler TJ, Starr T, Nagy TA, Sridhar S, Scott D, Winkler CW, Steele-Mortimer O, Detweiler CS, Peterson KE
Journal: Am J Pathol. 2016 Dec 7. pii: S0002-9440(16)30405-9. doi: 10.1016/j.ajpath.2016.09.002.
In the current study, we examined the ability of Salmonella enterica serovar Typhimurium to infect the central nervous system and cause meningitis following the natural route of infection in mice. C57BL/6J mice are extremely susceptible to systemic infection by Salmonella Typhimurium because of loss-of-function mutations in Nramp1 (SLC11A1), a phagosomal membrane protein that controls iron export from vacuoles and inhibits Salmonella growth in macrophages. Therefore, we assessed the ability of Salmonella to disseminate to the central nervous system (CNS) after oral infection in C57BL/6J mice expressing either wild-type (resistant) or mutant (susceptible) alleles of Nramp1. In both strains, oral infection resulted in focal meningitis and ventriculitis with recruitment of inflammatory monocytes to the CNS. In susceptible Nramp1-/- mice, there was a direct correlation between bacteremia and the number of bacteria in the brain, which was not observed in resistant Nramp1+/+ mice. A small percentage of Nramp1+/+ mice developed severe ataxia, which was associated with high bacterial loads in the CNS as well as clear histopathology of necrotizing vasculitis and hemorrhage in the brain. Thus, Nramp1 is not essential for Salmonella entry into the CNS or neuroinflammation, but may influence the mechanisms of CNS entry as well as the severity of meningitis.
Authors: Nash SH, Liao LM, Harris TB, Freedman ND
Journal: Am J Prev Med. 2016 Nov 22. pii: S0749-3797(16)30517-7. doi: 10.1016/j.amepre.2016.09.036. [Epub ahead of print]
INTRODUCTION: Tobacco use remains a leading modifiable cause of cancer incidence and premature mortality in the U.S. and globally. Despite increasing life expectancy worldwide, less is known about the effects of cigarette smoking on older populations. This study sought to determine the effects of smoking on mortality in older age.
METHODS: Associations of mortality with self-reported age at smoking cessation, age at smoking initiation, and amount smoked after age 70years were examined in 160,113 participants of the NIH-AARP Diet and Health Study aged >70 years. Participants completed a questionnaire detailing their smoking use in 2004-2005, and were followed for mortality through December 31, 2011. Analyses were conducted between 2014 and 2016.
RESULTS: Relative to never smokers, current smokers were more likely to die during follow-up (hazard ratio, 3.18; 95% CI=3.04, 3.31). Furthermore, former smokers had lower risks than current smokers (hazard ratios for quitting between ages 30-39, 40-49, 50-59, and 60-69 years were 0.41 [95% CI=0.39, 0.43], 0.51 [95% CI=0.49, 0.54], 0.64 [95% CI=0.61, 0.67], and 0.77 [95% CI=0.73, 0.81], respectively). Among current smokers, mortality was inversely associated with age at initiation, but directly associated with the number of cigarettes smoked per day at age >70 years.
CONCLUSIONS: As among younger people, lifetime cigarette smoking history is a key determinant of mortality after age 70 years.
Authors: House JS, Wyss AB, Hoppin JA, Richards M, Long S, Umbach DM, Henneberger PK, Beane Freeman LE, Sandler DP, Long O'Connell E, Barker-Cummings C, London SJ
Journal: J Allergy Clin Immunol. 2016 Nov 12. pii: S0091-6749(16)31284-2. doi: 10.1016/j.jaci.2016.09.036. [Epub ahead of print]
BACKGROUND: Previous studies, mostly from Europe, suggest that early-life farming exposures protect against childhood asthma and allergy; few data exist on asthma and allergy in adults.
OBJECTIVE: We sought to examine associations between early-life farming exposures and current asthma and atopy in an older adult US farming population.
METHODS: We analyzed data from 1746 farmers and 1555 spouses (mean age, 63) from a case-control study nested within the AgriculturalHealth Study. Current asthma and early-life farming exposures were assessed via questionnaires. We defined atopy based on specific IgE > 0.70 IU/mL to at least 1 of 10 allergens measured in blood. We used logistic regression, adjusted for age, sex, race, state (Iowa or North Carolina), and smoking (pack years), to estimate associations between early-life exposures and asthma (1198 cases and 2031 noncases) or atopy (578 cases and 2526 noncases).
RESULTS: Exposure to the farming environment in utero and in early childhood had little or no association with asthma but was associated with reduced odds of atopy. The strongest association was seen for having a mother who performed farm activities while pregnant (odds ratio, 0.60; 95% CI, 0.48-0.74) and remained significant in models with correlated early-life exposures including early childhood farm animal contact and raw milk consumption.
CONCLUSIONS: In a large US farming population, early-life farm exposures, particularly maternal farming activities while pregnant, were strongly associated with reduced risk of atopy in adults. These results extend previous work done primarily on childhood outcomes and suggest that protective associations of early-life farming exposures on atopy endure across the life course.
Authors: Sudre G, Choudhuri S, Szekely E, Bonner T, Goduni E, Sharp W, Shaw P
Journal: JAMA Psychiatry. 2016 Nov 16. doi: 10.1001/jamapsychiatry.2016.3072
IMPORTANCE: Despite its high heritability, few risk genes have been identified for attention-deficit/hyperactivity disorder (ADHD). Brain-based phenotypes could aid gene discovery. There is a myriad of structural and functional connections that support cognition. Disruption of such connectivity is a key pathophysiologic mechanism for ADHD, and identifying heritable phenotypes within these connections could provide candidates for genomic studies.
OBJECTIVE: To identify the structural and functional connections that are heritable and pertinent to ADHD.
DESIGN, SETTING, AND PARTICIPANTS: Members of extended multigenerational families enriched for ADHD were evaluated. Structuralconnectivity was defined by diffusion tensor imaging (DTI) of white matter tract microstructure and functional connectivity through resting-state functional magnetic resonance imaging (rsfMRI). Heritability and association with ADHD symptoms were estimated in 24 extended multigenerational families enriched for ADHD (305 members with clinical phenotyping, 213 with DTI, and 193 with rsfMRI data). Findings were confirmed in 52 nuclear families (132 members with clinical phenotypes, 119 with DTI, and 84 with rsfMRI). The study and data analysis were conducted from April 1, 2010, to September 1, 2016.
RESULTS: In the 52 nuclear families, 86 individuals (65.2%) were male and the mean (SD) age at imaging was 20.9 (15.0) years; in the 24 multigenerational extended families, 145 individuals (47.5%) were male and mean age at imaging was 30.4 (19.7) years. Microstructural properties of white matter tracts connecting ipsilateral cortical regions and the corpus callosum were significantly heritable, ranging from total additive genetic heritability (h2) = 0.69 (SE, 0.13; P = .0000002) for radial diffusivity of the right superior longitudinal fasciculus to h2 = 0.46 (SE, 0.15; P = .0009) for fractional anisotropy of the right inferior fronto-occipital fasciculus. Association with ADHD symptoms was found in several tracts, most strongly for the right superior longitudinal fasciculus (t = -3.05; P = .003). Heritable patterns of functional connectivity were detected within the default mode (h2 = 0.36; SE, 0.16; cluster level significance, P < .002), cognitive control (h2 = 0.32; SE, 0.15; P < .002), and ventral attention networks (h2 = 0.36; SE, 0.16; P < .002). In all cases, subregions within each network showed heritable functional connectivity with the rest of that network. More symptoms of hyperactivity/impulsivity (t = -2.63; P = .008) and inattention (t = -2.34; P = .02) were associated with decreased functional connectivitywithin the default mode network. Some cross-modal correlations were purely phenotypic, such as that between axial diffusivity of the right superior longitudinal fasciculus and heritable aspects of the default mode network (phenotypic correlation, ρp = -0.12; P = .03). A genetic cross-modal correlation was seen between the ventral attention network and radial diffusivity of the right inferior fronto-occipital fasciculus (genetic correlation, ρg = -0.45, P = .02).
CONCLUSIONS: Analysis of data on multigenerational extended and nuclear families identified the features of structural and functionalconnectivity that are both significantly heritable and associated with ADHD. In addition, shared genetic factors account for some phenotypic correlations between functional and structural connections. Such work helps to prioritize the facets of the brain's connectivityfor future genomic studies.
Authors: Lui JC, Garrison P, Nguyen Q, Ad M, Keembiyehetty C, Chen W, Jee YH, Landman E, Nilsson O, Barnes KM, Baron J
Journal: Nat Commun. 2016 Nov 29;7:13685. doi: 10.1038/ncomms13685.
Histone methyltransferases EZH1 and EZH2 catalyse the trimethylation of histone H3 at lysine 27 (H3K27), which serves as an epigenetic signal for chromatin condensation and transcriptional repression. Genome-wide associated studies have implicated EZH2 in the control of height and mutations in EZH2 cause Weaver syndrome, which includes skeletal overgrowth. Here we show that the combined loss of Ezh1 and Ezh2 in chondrocytes severely impairs skeletal growth in mice. Both of the principal processes underlying growth plate chondrogenesis, chondrocyte proliferation and hypertrophy, are compromised. The decrease in chondrocyte proliferation is due in part to derepression of cyclin-dependent kinase inhibitors Ink4a/b, while ineffective chondrocyte hypertrophy is due to the suppression of IGF signalling by the increased expression of IGF-binding proteins. Collectively, our findings reveal a critical role for H3K27 methylation in the regulation of chondrocyte proliferation and hypertrophy in the growth plate, which are the central determinants of skeletal growth.
Authors: Huang J, Kang BH, Ishida E, Zhou T, Griesman T, Sheng Z, Wu F, Doria-Rose NA, Zhang B, McKee K, O'Dell S, Chuang GY, Druz A, Georgiev IS, Schramm CA, Zheng A, Joyce MG, Asokan M, Ransier A, Darko S, Migueles SA, Bailer RT, Louder MK, Alam SM, Parks R, Kelsoe G, Von Holle T, Haynes BF, Douek DC, Hirsch V, Seaman MS, Shapiro L, Mascola JR, Kwong PD, Connors M
Journal: Immunity. 2016 Nov 15;45(5):1108-1121. doi: 10.1016/j.immuni.2016.10.027
Detailed studies of the broadly neutralizing antibodies (bNAbs) that underlie the best available examples of the humoral immune response to HIV are providing important information for the development of therapies and prophylaxis for HIV-1 infection. Here, we report a CD4-bindingsite (CD4bs) antibody, named N6, that potently neutralized 98% of HIV-1 isolates, including 16 of 20 that were resistant to other members of its class. N6 evolved a mode of recognition such that its binding was not impacted by the loss of individual contacts across the immunoglobulin heavy chain. In addition, structural analysis revealed that the orientation of N6 permitted it to avoid steric clashes with glycans, which is a common mechanism of resistance. Thus, an HIV-1-specific bNAb can achieve potent, near-pan neutralization of HIV-1, making it an attractive candidate for use in therapy and prophylaxis.
Authors: Bennuru S, Cotton JA, Ribeiro JM, Grote A, Harsha B, Holroyd N, Mhashilkar A, Molina DM, Randall AZ, Shandling AD, Unnasch TR, Ghedin E, Berriman M, Lustigman S, Nutman TB
Journal: MBio. 2016 Nov 23;7(6). pii: e02028-16. doi: 10.1128/mBio.02028-16.
Onchocerciasis (river blindness) is a neglected tropical disease that has been successfully targeted by mass drug treatment programs in the Americas and small parts of Africa. Achieving the long-term goal of elimination of onchocerciasis, however, requires additional tools, including drugs, vaccines, and biomarkers of infection. Here, we describe the transcriptome and proteome profiles of the major vector and the human host stages (L1, L2, L3, molting L3, L4, adult male, and adult female) of Onchocerca volvulus along with the proteome of each parasitic stage and of its Wolbachia endosymbiont (wOv). In so doing, we have identified stage-specific pathways important to the parasite's adaptation to its human host during its early development. Further, we generated a protein array that, when screened with well-characterized human samples, identified novel diagnostic biomarkers of O. volvulus infection and new potential vaccine candidates. This immunomic approach not only demonstrates the power of this postgenomic discovery platform but also provides additional tools for onchocerciasis control programs.
IMPORTANCE: The global onchocerciasis (river blindness) elimination program will have to rely on the development of new tools (drugs, vaccines, biomarkers) to achieve its goals by 2025. As an adjunct to the completed genomic sequencing of O. volvulus, we used a comprehensive proteomic and transcriptomic profiling strategy to gain a comprehensive understanding of both the vector-derived and human host-derived parasite stages. In so doing, we have identified proteins and pathways that enable novel drug targeting studies and the discovery of novel vaccine candidates, as well as useful biomarkers of active infection.
Authors: Lu Y, Biancotto A, Cheung F, Remmers E, Shah N, McCoy JP, Tsang JS
Journal: Immunity. 2016 Nov 15;45(5):1162-1175. doi: 10.1016/j.immuni.2016.10.025
Cell-to-cell expression variation (CEV) is a prevalent feature of even well-defined cell populations, but its functions, particularly at the organismal level, are not well understood. Using single-cell data obtained via high-dimensional flow cytometry of T cells as a model, we introduce an analysis framework for quantifying CEV in primary cell populations and studying its functional associations in human cohorts. Analyses of 840 CEV phenotypes spanning multiple baseline measurements of 14 proteins in 28 T cell subpopulations suggest that the quantitative extent of CEV can exhibit substantial subject-to-subject differences and yet remain stable within healthy individuals over months. We linked CEV to age and disease-associated genetic polymorphisms, thus implicating CEV as a biomarker of aging and disease susceptibility and suggesting that it might play an important role in health and disease. Our dataset, interactive figures, and software for computing CEV with flow cytometry data provide a resource for exploring CEV functions.
Authors: Ogburn RN, Randall TA, Xu Y, Roberts JH, Mebrahtu B, Karnuta JM, Rider SD, Kissling GE, London RE, Pomés A, Arlian L, Fitzgerald MC, Mueller GA
Journal: J Allergy Clin Immunol. 2016 Oct 13. pii: S0091-6749(16)30963-0. doi: 10.1016/j.jaci.2016.08.016. [Epub ahead of print]
Letter to the Editor
Authors: Gierach GL, Curtis RE, Pfeiffer RM, Mullooly M, Ntowe EA, Hoover RN, Nyante SJ, Feigelson HS, Glass AG, Berrington de Gonzalez A
Journal: JAMA Oncol. 2016 Oct 6. doi: 10.1001/jamaoncol.2016.3340. [Epub ahead of print]
IMPORTANCE: Within 10 years after breast cancer diagnosis, roughly 5% of patients develop contralateral breast cancer (CBC). Randomized trials have found that therapy including tamoxifen citrate and aromatase inhibitors (AIs) reduces CBC risk. But little is known about the magnitude and duration of protective associations within the context of real-world clinical management settings, where varying durations of and gaps in treatment are common.
OBJECTIVE: To determine the association between adjuvant tamoxifen and AI therapy and CBC risk within a general community setting.
DESIGN, SETTING, AND PARTICIPANTS: A retrospective cohort study of CBC risk among 7541 patients diagnosed with a first primary unilateral invasive breast cancer at Kaiser Permanente Institute for Health Research (Colorado) or Kaiser Permanente Northwest Center for Health Research (Oregon) between January 1, 1990, and December 31, 2008. Data were analyzed from 1 year after diagnosis of the first breast cancer through the earliest of the following events: CBC diagnosis, other second cancer diagnosis, death, last tumor registry follow-up, exit from the Kaiser Permanente health care plan, or end of study follow-up (December 31, 2010, for Oregon and December 31, 2011, for Colorado).
EXPOSURES: Adjuvant tamoxifen use and AI therapy were treated as time-dependent exposures, assessed using electronic prescription records.
MAIN OUTCOMES AND MEASURES: Incident CBC based on long-term systematic follow-up.
RESULTS: Among 7541 women with invasive breast cancer, median age at initial breast cancer diagnosis was 60.6 years (age range, 24.9-84.9 years). Women were predominantly (92.9% [7009 of 7541]) of white race. During a median of 6.3 years (range, 1-20.9 years) of follow-up, 248 women developed CBC (45 in situ and 203 invasive). Contralateral breast cancer risk decreased significantly with increasing tamoxifen therapy duration. In current users, the relative risk (RR) per year of tamoxifen use was 0.76 (95% CI, 0.64-0.89), with an estimated 66% (RR, 0.34; 95% CI, 0.29-0.40) RR reduction for 4 years of use compared with nonusers. Risk reductions were slightly smaller for past users but were still significant at least 5 years after stopping tamoxifen therapy (RR per year of use, 0.85; 95% CI, 0.71-0.995). In addition, AI use without tamoxifen therapy was associated with reduced CBC risk (RR for AI users compared with nonusers, 0.48; 95% CI, 0.22-0.97). Risk reductions were most apparent among women whose primary and CBCs were estrogen receptor positive.
CONCLUSIONS AND RELEVANCE: Tamoxifen therapy was associated with reduced CBC risk during treatment and after its cessation, with risk progressively decreasing as tamoxifen therapy duration increased. Among those surviving at least 5 years, tamoxifen use for at least 4 years was estimated to prevent 3 CBCs per 100 women by 10 years after an estrogen receptor-positive first breast cancer, an absolute risk reduction that is consistent with findings from clinical trials. If adjuvant endocrine therapy is indicated for breast cancer treatment, these findings in concert with trial data suggest that women should be encouraged to complete the full course.