MicroRNA-155 Deficiency Attenuates Liver Steatosis and Fibrosis without Reducing Inflammation in a Mouse Model of Steatohepatitis
BACKGROUND and AIM: MicroRNAs (miRs) regulate hepatic steatosis, inflammation and fibrosis. Fibrosis is the consequence of chronic tissue damage and inflammation. We hypothesized that deficiency of miR-155, a master regulator of inflammation, attenuates steatohepatitis and fibrosis.
METHODS: Wild type (WT) and miR-155-deficient (KO) mice were fed methionine-choline-deficient (MCD) or -supplemented (MCS) control diet for 5 weeks. Liver injury, inflammation, steatosis and fibrosis were assessed.
RESULTS: MCD diet resulted in steatohepatitis and increased miR-155 expression in total liver, hepatocytes and Kupffer cells. Steatosis and expression of genes involved in fatty acid metabolism were attenuated in miR-155 KO mice after MCD feeding. In contrast, miR-155 deficiency failed to attenuate inflammatory cell infiltration, nuclear factor kappa beta (NF-kappaB) activation and enhanced the expression of the pro-inflammatory cytokines tumor necrosis factor alpha (TNFalpha) and monocyte chemoattractant protein-1 (MCP1) in MCD diet-fed mice. We found a significant attenuation of apoptosis (cleaved caspase-3) and reduction in collagen and alpha smooth muscle actin (alphaSMA) levels in miR-155 KO mice compared to WTs on MCD diet. In addition, we found attenuation of platelet derived growth factor (PDGF), a pro-fibrotic cytokine; SMAD family member 3 (Smad3), a protein involved in transforming growth factor-beta (TGFbeta) signal transduction and vimentin, a mesenchymal marker and indirect indicator of epithelial-to-mesenchymal transition (EMT) in miR-155 KO mice. Nuclear binding of CCAAT enhancer binding protein beta (C/EBPbeta) a miR-155 target involved in EMT was significantly increased in miR-155 KO compared to WT mice.
CONCLUSIONS: Our novel data demonstrate that miR-155 deficiency can reduce steatosis and fibrosis without decreasing inflammation in steatohepatitis.
The fungus Cryptococcus is a major cause of meningoencephalitis in HIV-infected as well as HIV-uninfected individuals with mortalities in developed countries of 20% and 30%, respectively. In HIV-related disease, defects in T-cell immunity are paramount, whereas there is little understanding of mechanisms of susceptibility in non-HIV related disease, especially that occurring in previously healthy adults. The present description is the first detailed immunological study of non-HIV-infected patients including those with severe central nervous system (s-CNS) disease to 1) identify mechanisms of susceptibility as well as 2) understand mechanisms underlying severe disease. Despite the expectation that, as in HIV, T-cell immunity would be deficient in such patients, cerebrospinal fluid (CSF) immunophenotyping, T-cell activation studies, soluble cytokine mapping and tissue cellular phenotyping demonstrated that patients with s-CNS disease had effective microbiological control, but displayed strong intrathecal expansion and activation of cells of both the innate and adaptive immunity including HLA-DR+ CD4+ and CD8+ cells and NK cells. These expanded CSF T cells were enriched for cryptococcal-antigen specific CD4+ cells and expressed high levels of IFN-gamma as well as a lack of elevated CSF levels of typical T-cell specific Th2 cytokines -- IL-4 and IL-13. This inflammatory response was accompanied by elevated levels of CSF NFL, a marker of axonal damage, consistent with ongoing neurological damage. However, while tissue macrophage recruitment to the site of infection was intact, polarization studies of brain biopsy and autopsy specimens demonstrated an M2 macrophage polarization and poor phagocytosis of fungal cells. These studies thus expand the paradigm for cryptococcal disease susceptibility to include a prominent role for macrophage activation defects and suggest a spectrum of disease whereby severe neurological disease is characterized by immune-mediated host cell damage.
High rate of subclinical chikungunya virus infection and association of neutralizing antibody with protection in a prospective cohort in the Philippines
BACKGROUND: Chikungunya virus (CHIKV) is a globally re-emerging arbovirus for which previous studies have indicated the majority of infections result in symptomatic febrile illness. We sought to characterize the proportion of subclinical and symptomatic CHIKV infections in a prospective cohort study in a country with known CHIKV circulation.
METHODS/FINDINGS: A prospective longitudinal cohort of subjects > /=6 months old underwent community-based active surveillance for acute febrile illness in Cebu City, Philippines from 2012-13. Subjects with fever history were clinically evaluated at acute, 2, 5, and 8 day visits, and at a 3-week convalescent visit. Blood was collected at the acute and 3-week convalescent visits. Symptomatic CHIKV infections were identified by positive CHIKV PCR in acute blood samples and/or CHIKV IgM/IgG ELISA seroconversion in paired acute/convalescent samples. Enrollment and 12-month blood samples underwent plaque reduction neutralization test (PRNT) using CHIKV attenuated strain 181/clone25. Subclinical CHIKV infections were identified by > /=8-fold rise from a baseline enrollment PRNT titer < 10 without symptomatic infection detected during the intervening surveillance period. Selected CHIKV PCR-positive samples underwent viral isolation and envelope protein-1 gene sequencing. Of 853 subjects who completed all study procedures at 12 months, 19 symptomatic infections (2.19 per 100 person-years) and 87 subclinical infections (10.03 per 100 person-years) occurred. The ratio of subclinical-to-symptomatic infections was 4.6:1 varying with age from 2:1 in 6 month-5 year olds to 12:1 in those > 50 years old. Baseline CHIKV PRNT titer > /=10 was associated with 100% (95%CI: 46.1, 100.0) protection from symptomatic CHIKV infection. Phylogenetic analysis demonstrated Asian genotype closely related to strains from Asia and the Caribbean.
CONCLUSIONS: Subclinical infections accounted for a majority of total CHIKV infections. A positive baseline CHIKV PRNT titer was associated with protection from symptomatic CHIKV infection. These findings have implications for assessing disease burden, understanding virus transmission, and supporting vaccine development.
Downregulation of the Host Gene jigr1 by miR-92 Is Essential for Neuroblast Self-Renewal in Drosophila
Intragenic microRNAs (miRNAs), located mostly in the introns of protein-coding genes, are often co-expressed with their host mRNAs. However, their functional interaction in development is largely unknown. Here we show that in Drosophila, miR-92a and miR-92b are embedded in the intron and 3'UTR of jigr1, respectively, and co-expressed with some jigr1 isoforms. miR-92a and miR-92b are highly expressed in neuroblasts of larval brain where Jigr1 expression is low. Genetic deletion of both miR-92a and miR-92b demonstrates an essential cell-autonomous role for these miRNAs in maintaining neuroblast self-renewal through inhibiting premature differentiation. We also show that miR-92a and miR-92b directly target jigr1 in vivo and that some phenotypes due to the absence of these miRNAs are partially rescued by reducing the level of jigr1. These results reveal a novel function of the miR-92 family in Drosophila neuroblasts and provide another example that local negative feedback regulation of host genes by intragenic miRNAs is essential for animal development.
Phosphorylation of the Peptidoglycan Synthase PonA1 Governs the Rate of Polar Elongation in Mycobacteria
Cell growth and division are required for the progression of bacterial infections. Most rod-shaped bacteria grow by inserting new cell wall along their mid-section. However, mycobacteria, including the human pathogen Mycobacterium tuberculosis, produce new cell wall material at their poles. How mycobacteria control this different mode of growth is incompletely understood. Here we find that PonA1, a penicillin binding protein (PBP) capable of transglycosylation and transpeptidation of cell wall peptidoglycan (PG), is a major governor of polar growth in mycobacteria. PonA1 is required for growth of Mycobacterium smegmatis and is critical for M. tuberculosis during infection. In both cases, PonA1's catalytic activities are both required for normal cell length, though loss of transglycosylase activity has a more pronounced effect than transpeptidation. Mutations that alter the amount or the activity of PonA1 result in abnormal formation of cell poles and changes in cell length. Moreover, altered PonA1 activity results in dramatic differences in antibiotic susceptibility, suggesting that a balance between the two enzymatic activities of PonA1 is critical for survival. We also find that phosphorylation of a cytoplasmic region of PonA1 is required for normal activity. Mutations in a critical phosphorylated residue affect transglycosylase activity and result in abnormal rates of cell elongation. Together, our data indicate that PonA1 is a central determinant of polar growth in mycobacteria, and its governance of cell elongation is required for robust cell fitness during both host-induced and antibiotic stress.
Article introduction: Life expectancy has dramatically increased in recent human history. As a result, neurodegenerative diseases have become a primary health issue. Circadian clocks are found in all mammalian tissues, including neurons and glia, and are, thus, likely to have an impact on the onset and progression of neurodegenerative diseases. However, the link between circadian clocks and neurodegeneration is poorly understood. ...
Time-locked sequences of neural activity can be found throughout the vertebrate forebrain in various species and behavioral contexts. From "time cells" in the hippocampus of rodents to cortical activity controlling movement, temporal sequence generation is integral to many forms of learned behavior. However, the mechanisms underlying sequence generation are not well known. Here, we describe a spatial and temporal organization of the songbird premotor cortical microcircuit that supports sparse sequences of neural activity. Multi-channel electrophysiology and calcium imaging reveal that neural activity in premotor cortex is correlated with a length scale of 100 microm. Within this length scale, basal-ganglia-projecting excitatory neurons, on average, fire at a specific phase of a local 30 Hz network rhythm. These results show that premotor cortical activity is inhomogeneous in time and space, and that a mesoscopic dynamical pattern underlies the generation of the neural sequences controlling song.
Manuscript abstract: Nonsense mutations promote premature translational termination and cause anywhere from 5-70% of the individual cases of most inherited diseases. Studies on nonsense-mediated cystic fibrosis have indicated that boosting specific protein synthesis from less than 1% to as little as 5% of normal levels may greatly reduce the severity or eliminate the principal manifestations of disease. To address the need for a drug capable of suppressing premature termination, we identified PTC124-a new chemical entity that selectively induces ribosomal readthrough of premature but not normal termination codons. PTC124 activity, optimized using nonsense-containing reporters, promoted dystrophin production in primary muscle cells from humans and mdx mice expressing dystrophin nonsense alleles, and rescued striated muscle function in mdx mice within 2-8 weeks of drug exposure. PTC124 was well tolerated in animals at plasma exposures substantially in excess of those required for nonsense suppression. The selectivity of PTC124 for premature termination codons, its well characterized activity profile, oral bioavailability and pharmacological properties indicate that this drug may have broad clinical potential for the treatment of a large group of genetic disorders with limited or no therapeutic options.
Influence of family, friend and coworker social support and social undermining on weight gain prevention among adults
OBJECTIVE: Examine longitudinal associations between sources of social support and social undermining for healthy eating and physical activity and weight change.
METHODS: Data are from 633 employed adults participating in a cluster-randomized multilevel weight gain prevention intervention. Primary predictors included social support and social undermining for two types of behaviors (healthy eating and physical activity) from three sources (family, friends, and coworkers) obtained via self-administered surveys. The primary outcome (weight in kg) was measured by trained staff. Data were collected at baseline, 12 months, and 24 months. Linear multivariable models examined the association of support and social undermining with weight over time, adjusting for intervention status, time, gender, age, education, and clustering of individuals within schools.
RESULTS: Adjusting for all primary predictors and covariates, friend support for healthy eating (beta = -0.15), coworker support for healthy eating (beta = -0.11), and family support for physical activity (beta = -0.032) were associated with weight reduction at 24 months (P-values < 0.05). Family social undermining for healthy eating was associated with weight gain at 24 months (beta = 0.12; P = 0.0019).
CONCLUSIONS: Among adult employees, friend and coworker support for healthy eating and family support for physical activity predicted improved weight management. Interventions that help adults navigate family social undermining of healthy eating are warranted.
Crosstalk between BRCA-Fanconi anemia and mismatch repair pathways prevents MSH2-dependent aberrant DNA damage responses
Several proteins in the BRCA-Fanconi anemia (FA) pathway, such as FANCJ, BRCA1, and FANCD2, interact with mismatch repair (MMR) pathway factors, but the significance of this link remains unknown. Unlike the BRCA-FA pathway, the MMR pathway is not essential for cells to survive toxic DNA interstrand crosslinks (ICLs), although MMR proteins bind ICLs and other DNA structures that form at stalled replication forks. We hypothesized that MMR proteins corrupt ICL repair in cells that lack crosstalk between BRCA-FA and MMR pathways. Here, we show that ICL sensitivity of cells lacking the interaction between FANCJ and the MMR protein MLH1 is suppressed by depletion of the upstream mismatch recognition factor MSH2. MSH2 depletion suppresses an aberrant DNA damage response, restores cell cycle progression, and promotes ICL resistance through a Rad18-dependent mechanism. MSH2 depletion also suppresses ICL sensitivity in cells deficient for BRCA1 or FANCD2, but not FANCA. Rescue by Msh2 loss was confirmed in Fancd2-null primary mouse cells. Thus, we propose that regulation of MSH2-dependent DNA damage response underlies the importance of interactions between BRCA-FA and MMR pathways.
Mismatch repair proteins and AID activity are required for the dominant negative function of C-terminally deleted AID in class switching
Activation-induced cytidine deaminase (AID) is essential for class-switch recombination (CSR) and somatic hypermutation (SHM) of Ig genes. The AID C terminus is required for CSR, but not for S-region DNA double-strand breaks (DSBs) during CSR, and it is not required for SHM. AID lacking the C terminus (DeltaAID) is a dominant negative (DN) mutant, because human patients heterozygous for this mutant fail to undergo CSR. In agreement, we show that DeltaAID is a DN mutant when expressed in AID-sufficient mouse splenic B cells. To have DN function, DeltaAID must have deaminase activity, suggesting that its ability to induce DSBs is important for the DN function. Supporting this hypothesis, Msh2-Msh6 have been shown to contribute to DSB formation in S regions, and we find in this study that Msh2 is required for the DN activity, because DeltaAID is not a DN mutant in msh2(-/-) cells. Our results suggest that the DNA DSBs induced by DeltaAID are unable to participate in CSR and might interfere with the ability of full-length AID to participate in CSR. We propose that DeltaAID is impaired in its ability to recruit nonhomologous end joining repair factors, resulting in accumulation of DSBs that undergo aberrant resection. Supporting this hypothesis, we find that the S-S junctions induced by DeltaAID have longer microhomologies than do those induced by full-length AID. In addition, our data suggest that AID binds Smu regions in vivo as a monomer.
BACKGROUND: Despite national guidelines recommending bone mineral density screening with dual-energy x-ray absorptiometry (DXA) in women aged 65 years and older, many women do not receive initial screening.
OBJECTIVE: To determine the effectiveness of health system and patient-level interventions designed to increase appropriate DXA testing and osteoporosis treatment through (1) an invitation to self-refer for DXA (self-referral); (2) self-referral plus patient educational materials; and (3) usual care (UC, physician referral).
RESEARCH DESIGN: Parallel, group-randomized, controlled trials performed at Kaiser Permanente Northwest (KPNW) and Kaiser Permanente Georgia (KPG). SUBJECTS: Women aged 65 years and older without a DXA in past 5 years.
MEASURES: DXA completion rates 90 days after intervention mailing and osteoporosis medication receipt 180 days after initial intervention mailing.
RESULTS: From > 12,000 eligible women, those randomized to self-referral were significantly more likely to receive a DXA than UC (13.0%-24.1% self-referral vs. 4.9%-5.9% UC, P < 0.05). DXA rates did not significantly increase with patient educational materials. Osteoporosis was detected in a greater proportion of self-referral women compared with UC (P < 0.001). The number needed to receive an invitation to result in a DXA in KPNW and KPG regions was approximately 5 and 12, respectively. New osteoporosis prescription rates were low (0.8%-3.4%) but significantly greater among self-referral versus UC in KPNW.
CONCLUSIONS: DXA rates significantly improved with a mailed invitation to schedule a scan without physician referral. Providing women the opportunity to self-refer may be an effective, low-cost strategy to increase access for recommended osteoporosis screening.
Physician profiling methods are envisioned as a means of promoting healthcare quality by recognizing the contributions of individual physicians. Developing methods that can reliably distinguish among physicians' performance is challenging because of small sample sizes, incomplete data, and physician panel differences. In this study, we developed a hierarchical, weighted composite model to reliably compare primary care physicians across domains of care, and we demonstrated its use within a clinical system. We evaluated 199 primary care physicians from a large integrated healthcare delivery system using 19 quality and two efficiency measures taken from the Healthcare Effectiveness Data and Information Set and existing pay-for-performance programs. Individual measures were calculated, compared to benchmarks, and grouped into two composites: one focused on quality and one on efficiency. Each composite was fitted to the model, assessed for reliability (signal-to-noise ratio), and weighted to create a single summary score for each primary care physician. The quality-of-care composite had a median reliability of .98, with 99.5% of all physician reliability estimates exceeding threshold. The efficiency composite had a median reliability of .97, with 94.9% of all physician reliability estimates exceeding threshold. Our results demonstrate that reliable physician profiling is possible across care domains using a hierarchical composite model based on multiple data. The model was used to distribute incentive payouts among primary care physicians but is adaptable to many settings.
PURPOSE: Encouraging dog walking may increase physical activity in dog owners. This cluster-randomized controlled trial investigated whether a social networking Web site (Meetup) could be used to deliver a multicomponent dog walking intervention to increase physical activity.
METHODS: Sedentary dog owners (n = 102) participated. Eight neighborhoods were randomly assigned to the Meetup condition (Meetup) or a condition where participants received monthly e-mails with content from the American Heart Association regarding increasing physical activity. The Meetup intervention was delivered over 6 months and consisted of newsletters, dog walks, community events, and an activity monitor. The primary outcome was steps; secondary outcomes included social support for walking, sense of community, perceived dog walking outcomes, barriers to dog walking, and feasibility of the intervention.
RESULTS: Mixed-model analyses examined change from baseline to postintervention (6 months) and whether change in outcomes differed by condition. Daily steps increased over time (P = 0.04, d = 0.28), with no differences by condition. The time-condition interaction was significant for the perceived outcomes of dog walking (P = 0.04, d = 0.40), such that the Meetup condition reported an increase in the perceived positive outcomes of dog walking, whereas the American Heart Association condition did not. Social support, sense of community, and dog walking barriers did not significantly change. Meetup logins averaged 58.38 per week (SD, 11.62). Within 2 months of the intervention ending, organization of the Meetup groups transitioned from the study staff to Meetup members.
CONCLUSIONS: Results suggest that a Meetup group is feasible for increasing physical activity in dog owners. Further research is needed to understand how to increase participation in the Meetup group and facilitate greater connection among dog owners.
Comparison of trends in US health-related quality of life over the 2000s using the SF-6D, HALex, EQ-5D, and EQ-5D visual analog scale versus a broader set of symptoms and impairments
BACKGROUND: A number of instruments have been developed to measure health-related quality of life (HRQoL), differing in the health domains covered and their scoring. Although few such measures have been consistently included in US national health surveys over time, the surveys have included data on a broad range of symptoms and impairments, which enables the tracking of population health trends.
OBJECTIVES: To compare trends in HRQoL as measured using existing instruments versus using a broader range of symptoms and impairments collected in multiple years of nationally representative data.
DATA AND MEASURES: Data were from the 2000-2010 Medical Expenditure Panel Survey, which is nationally representative of the noninstitutionalized US population. Level of and trends in HRQoL derived from a broad range of survey symptoms and impairments (SSI) was compared with HRQoL from the SF-6D, the HALex, and, between 2000 and 2003, the EuroQol-5D (EQ-5D) and EQ-5D Visual Analog Scale.
RESULTS: Trends in HRQoL were similar using different measures. The SSI scores correlated 0.66-0.80 with scores from other measures and mean SSI scores were between those of other measures. Scores from all HRQoL measures declined similarly with increasing age and with the presence of comorbid conditions.
CONCLUSIONS: Measuring HRQoL using a broader range of symptoms and impairments than those in a single instrument yields population health trends similar to those from other measures while making maximum use of existing data and providing rich detail on the factors underlying change.
Facilitators and barriers to the active participation of clients with serious mental illnesses in medication decision making: the perceptions of young adult clients
The active participation of young adults with serious mental illnesses (SMI) in making decisions about their psychotropic medications is beneficial to their care quality and overall health. Many however report not expressing treatment preferences to psychiatrists. Qualitative methods were used to interview 24 young adults with SMI about their experiences making medication decisions with their psychiatrists. An inductive analytic approach was taken to identifying conceptual themes in the transcripts. Respondents reported that the primary facilitators to active participation were the psychiatrist's openness to the client's perspective, the psychiatrist's availability outside of office hours, the support of other mental health providers, and personal growth and self-confidence of the young adults. The primary barriers to active participation reported were the resistance of the psychiatrist, the lack of time for consultations, and limited client self-efficacy. Young adults with SMI can be active participants in making decisions about their psychiatric treatment.
Several studies have found a link between health literacy and participation in cancer screening. Most, however, have relied on self-report to determine screening status. Further, until now, health literacy measures have assessed print literacy only. The purpose of this study was to examine the relationship between participation in cervical cancer screening (Papanicolaou [Pap] testing) and two forms of health literacy-reading and listening. A demographically diverse sample was recruited from a pool of insured women in Georgia, Massachusetts, Hawaii, and Colorado between June 2009 and April 2010. Health literacy was assessed using the Cancer Message Literacy Test-Listening and the Cancer Message Literacy Test-Reading. Adherence to cervical cancer screening was ascertained through electronic administrative data on Pap test utilization. The relationship between health literacy and adherence to evidence-based recommendations for Pap testing was examined using multivariate logistic regression models. Data from 527 women aged 40 to 65 were analyzed and are reported here. Of these 527 women, 397 (75 %) were up to date with Pap testing. Higher health literacy scores for listening but not reading predicted being up to date. The fact that health literacy listening was associated with screening behavior even in this insured population suggests that it has independent effects beyond those of access to care. Patients who have difficulty understanding spoken recommendations about cancer screening may be at risk for underutilizing screening as a result.
Characteristics of Contemporary Patients Discharged From the Hospital After an Acute Coronary Syndrome
BACKGROUND: Limited contemporary data compare the clinical and psychosocial characteristics and acute management of patients hospitalized with an initial vs a recurrent episode of acute coronary disease. We describe these factors in a cohort of patients recruited from 6 hospitals in Massachusetts and Georgia after an acute coronary syndrome.
MATERIALS AND METHODS: We performed structured baseline in-person interviews and medical record abstractions for 2174 eligible and consenting patients surviving hospitalization for an acute coronary syndrome between April 2011 and May 2013.
RESULTS: The average patient age was 61 years, 64% were men, and 47% had a high school education or less; 29% had a low general quality of life, and 1 in 5 were cognitively impaired. Patients with a recurrent coronary episode had a greater burden of previously diagnosed comorbidities. Overall, psychosocial burden was high, and more so in those with a recurrent vs those with an initial episode. Patients with an initial coronary episode were as likely to have been treated with all 4 effective cardiac medications (51.6%) as patients with a recurrent episode (52.3%), but were significantly more likely to have undergone cardiac catheterization (97.9% vs 92.9%) and a percutaneous coronary intervention (73.7% vs 60.9%) (P < .001) during their index hospitalization.
CONCLUSIONS: Patients with a first episode of acute coronary artery disease have a more favorable psychosocial profile, less comorbidity, and receive more invasive procedures but similar medical management, than patients with previously diagnosed coronary disease. Implications of the high psychosocial burden on various patient-related outcomes require investigation.
BACKGROUND: Patterns of adoption of acute care surgery (ACS) as a strategy for emergency general surgery (EGS) care are unknown.
METHODS: We conducted a qualitative study comprising face-to-face interviews with senior surgeons responsible for ACS at 18 teaching hospitals chosen to ensure diversity of opinions and practice environment (three practice types [community, public or charity, and university] in each of six geographic regions [Mid-Atlantic, Midwest, New England, Northeast, South, and West]). Interviews were recorded, transcribed, and analyzed using NVivo (QSR International, Melbourne, Australia). We applied the methods of investigator triangulation using an inductive approach to develop a final taxonomy of codes organized by themes related to respondents' views on the future of ACS as a strategy for EGS. We applied our findings to a conceptual model on diffusion of innovation.
RESULTS: We found a paradox between ACS viewed as a health care delivery innovation versus a rebranding of comprehensive general surgery. Optimism for the future of ACS because of increased desirability for trauma and critical care careers as well as improved EGS outcomes was tempered by fear over lack of continuity, poor institutional resources, and uncertainty regarding financial viability. Our analysis suggests that the implementation of ACS, whether a true health care delivery innovation or an innovative rebranding, fits into the Rogers' diffusion of innovation theory.
CONCLUSIONS: Despite concerns over resource allocation and the definition of the specialty, from the perspective of senior surgeons deeply entrenched in executing this care delivery model, ACS represents the new face of general surgery that will likely continue to diffuse from these early adopters.
The following work demonstrates that paternal diet controls medically important metabolic phenotypes in offspring. We observe transmission of dietary information to the zygote via sperm, and this information evades reprogramming that typically occurs after fertilization. Cytosine methylation is implicated as a major contributor to meiotic epigenetic inheritance in several transgenerational phenomena. Our extensive characterization of the sperm methylome reveals that diet does not significantly affect methylation patterns. However, we find that extensive epivariability in the sperm epigenome makes important contributions to offspring variation. Importantly, coordinate cytosine methylation and copy number changes over the ribosomal DNA locus contributes to variation in offspring metabolism. Thus, rDNA variability acts independently of postadolescent paternal diet to influence offspring metabolism. Therefore, at least two mechanisms exist for epigenetically controlling offspring metabolism: stochastic epivariation and diet acting by an unknown mechanism to further modulate metabolism. This work argues that an offspring's phenotype can no longer be viewed solely as the result of genetic interactions with the developmental environment - the additional influences of paternal environment and inherited epigenetic variability must also be considered. These findings reveal novel contributions to metabolism that could revolutionize how we think about the risk factors for human health and disease.