Poxviruses deploy genomic accordions to adapt rapidly against host antiviral defenses.

In contrast to RNA viruses, double-stranded DNA viruses have low mutation rates yet must still adapt rapidly in response to changing host defenses. To determine mechanisms of adaptation, we subjected the model poxvirus vaccinia to serial propagation in human cells, where its antihost factor K3L is maladapted against the antiviral protein kinase R (PKR). Viruses rapidly acquired higher fitness via recurrent K3L gene amplifications, incurring up to 7%-10% increases in genome size. These transient gene expansions were necessary and sufficient to counteract human PKR and facilitated the gain of an adaptive amino acid substitution in K3L that also defeats PKR. Subsequent reductions in gene amplifications offset the costs associated with larger genome size while retaining adaptive substitutions. Our discovery of viral "gene-accordions" explains how poxviruses can rapidly adapt to defeat different host defenses despite low mutation rates and reveals how classical Red Queen conflicts can progress through unrecognized intermediates.

The AIM2-like Receptors Are Dispensable for the Interferon Response to Intracellular DNA.

Detection of intracellular DNA triggers activation of the STING-dependent interferon-stimulatory DNA (ISD) pathway, which is essential for antiviral responses. Multiple DNA sensors have been proposed to activate this pathway, including AIM2-like receptors (ALRs). Whether the ALRs are essential for activation of this pathway remains unknown. To rigorously explore the function of ALRs, we generated mice lacking all 13 ALR genes. We found that ALRs are dispensable for the type I interferon (IFN) response to transfected DNA ligands, DNA virus infection, and lentivirus infection. We also found that ALRs do not contribute to autoimmune disease in the Trex1(-/-) mouse model of Aicardi-Goutières Syndrome. Finally, CRISPR-mediated disruption of the human AIM2-like receptor IFI16 in primary fibroblasts revealed that IFI16 is not essential for the IFN response to human cytomegalovirus infection. Our findings indicate that ALRs are dispensable for the ISD response and suggest that alternative functions for these receptors should be explored.

A single polymorphic residue in humans underlies species-specific restriction of HSV-1 by the antiviral protein MxB.

IMPORTANCE: Herpesviruses present a major global disease burden. Understanding the host cell mechanisms that block viral infections, as well as how viruses can evolve to counteract these host defenses, is critically important for understanding viral disease pathogenesis. This study reveals that the major human variant of the antiviral protein myxovirus resistance protein B (MxB) inhibits the human pathogen herpes simplex virus (HSV-1), whereas a minor human variant and orthologous MxB genes from even closely related primates do not. Thus, in contrast to the many antagonistic virus-host interactions in which the virus is successful in thwarting the host's defense systems, here the human gene appears to be at least temporarily winning at this interface of the primate-herpesvirus evolutionary arms race. Our findings further show that a polymorphism at amino acid 83 in a small fraction of the human population is sufficient to abrogate MxB's ability to inhibit HSV-1, which could have important implications for human susceptibility to HSV-1 pathogenesis.

Rapid adaptation to human protein kinase R by a unique genomic rearrangement in rhesus cytomegalovirus.

Cytomegaloviruses (CMVs) are generally unable to cross species barriers, in part because prolonged coevolution with one host species limits their ability to evade restriction factors in other species. However, the limitation in host range is incomplete. For example, rhesus CMV (RhCMV) can replicate in human cells, albeit much less efficiently than in rhesus cells. Previously we reported that the protein kinase R (PKR) antagonist encoded by RhCMV, rTRS1, has limited activity against human PKR but is nonetheless necessary and sufficient to enable RhCMV replication in human fibroblasts (HF). We now show that knockout of PKR in human cells or treatment with the eIF2B agonist ISRIB, which overcomes the translational inhibition resulting from PKR activation, augments RhCMV replication in HF, indicating that human PKR contributes to the inefficiency of RhCMV replication in HF. Serial passage of RhCMV in HF reproducibly selected for viruses with improved ability to replicate in human cells. The evolved viruses contain an inverted duplication of the terminal 6.8 kb of the genome, including rTRS1. The duplication replaces ~11.8 kb just downstream of an internal sequence element, pac1-like, which is very similar to the pac1 cleavage and packaging signal found near the terminus of the genome. Plaque-purified evolved viruses produced at least twice as much rTRS1 as the parental RhCMV and blocked the PKR pathway more effectively in HF. Southern blots revealed that unlike the parental RhCMV, viruses with the inverted duplication isomerize in a manner similar to HCMV and other herpesviruses that have internal repeat sequences. The apparent ease with which this duplication event occurs raises the possibility that the pac1-like site, which is conserved in Old World monkey CMV genomes, may serve a function in facilitating rapid adaptation to evolutionary obstacles.

Direct and Moderating Causal Effects of Network Support on Sleep Quality: Findings From the UC Berkeley Social Network Study.

BACKGROUND: Sleep is an important, restorative behavior for health, yet many adults report troubled sleep. The existence of a support network may be beneficial for sleep quality, including as a buffer for stressful events, yet few studies have examined these relationships longitudinally. PURPOSE: To examine the causal effect of changes in personal network support on sleep quality both directly and as a buffer of negative life events among young and older adults. METHODS: The UC Berkeley Social Network survey collected data from young (21-30 year old, n = 475) and late middle-age (50-70 year old, n = 637) adults across three waves between 2015 and 2018. Participants reported on personal network characteristics, negative life events, and number of nights with trouble falling and staying asleep. Fixed effects models are used to examine causal relationships among each age cohort. RESULTS: Direct effects of network support on sleep quality were observed among older adults. Insufficient practical support predicted higher rates of trouble falling asleep (incident rate ratio [IRR] = 1.40, p < .01), while a desire for more social companions predicted lower rates of trouble staying asleep (IRR = 0.81, p < .01). Buffering effects of network support on sleep quality were observed among young adults. Changes in partnership status buffer the negative effects of the death of a close tie on trouble falling asleep (IRR = 0.75, p < .01) and persistent difficulties paying bills on trouble staying asleep (IRR = 0.45, p < 0.001) among young adults. CONCLUSIONS: This study provides evidence for the direct and buffering role of network support on sleep quality. Our results indicate that efforts to improve sleep quality should address personal networks and the support they provide, perhaps especially during times of stress for younger adults.

Antagonism of the Protein Kinase R Pathway in Human Cells by Rhesus Cytomegalovirus.

While cytomegalovirus (CMV) infections are often limited in host range by lengthy coevolution with a single host species, a few CMVs are known to deviate from this rule. For example, rhesus macaque CMV (RhCMV), a model for human CMV (HCMV) pathogenesis and vaccine development, can replicate in human cells, as well as in rhesus cells. Both HCMV and RhCMV encode species-specific antagonists of the broadly acting host cell restriction factor protein kinase R (PKR). Although the RhCMV antagonist of PKR, rTRS1, has very limited activity against human PKR, here, we show it is essential for RhCMV replication in human cells because it prevents human PKR from phosphorylating the translation initiation factor eIF2α, thereby allowing continued translation and viral replication. Although rTRS1 is necessary for RhCMV replication, it is not sufficient to rescue replication of HCMV lacking its own PKR antagonists in human fibroblasts. However, overexpression of rTRS1 in human fibroblasts enabled HCMV expressing rTRS1 to replicate, indicating that elevated levels or early expression of a weak antagonist can counteract a resistant restriction factor like human PKR. Exploring potential mechanisms that might allow RhCMV to replicate in human cells revealed that RhCMV makes no less double-stranded RNA than HCMV. Rather, in human cells, RhCMV expresses rTRS1 at levels 2 to 3 times higher than those of the HCMV-encoded PKR antagonists during HCMV infection. These data suggest that even a modest increase in expression of this weak PKR antagonist is sufficient to enable RhCMV replication in human cells.IMPORTANCE Rhesus macaque cytomegalovirus (RhCMV) offers a valuable model for studying congenital human cytomegalovirus (HCMV) pathogenesis and vaccine development. Therefore, it is critical to understand variations in how each virus infects and affects its host species to be able to apply insights gained from the RhCMV model to HCMV. While HCMV is capable only of infecting cells from humans and very closely related species, RhCMV displays a wider host range, including human as well as rhesus cells. RhCMV expresses an antagonist of a broadly acting antiviral factor present in all mammalian cells, and its ability to counter both the rhesus and human versions of this host factor is a key component of RhCMV's ability to cross species barriers. Here, we examine the molecular mechanisms that allow this RhCMV antagonist to function against a human restriction factor.

Personal network characteristics and body mass index: the role of education among Black Americans.

BACKGROUND: Personal (i.e. egocentric) network characteristics are associated with health outcomes, including overweight and obesity. Previous research suggests educational attainment may interact with network characteristics to buffer these relationships. Limited research has examined the personal network characteristics of Black Americans, who have increased risk of overweight and obesity. The purpose of the current study was to examine associations between network characteristics and body mass index (BMI), and whether educational attainment modified these associations among Black Americans. METHODS: In 2014, using respondent-driven sampling, we recruited 430 adult residents of eight low-income neighborhoods in Greenville, SC. Self-administered questionnaires assessed structural and compositional characteristics (i.e. size, density) of respondents' personal networks, socio-demographic characteristics, and health-related behaviors and conditions. Multilevel regression models with robust sandwich estimation accounted for clustering within respondent chains. RESULTS: Among Black adults overall, network density-the number of connections among network members-was positively associated with BMI. Higher education moderated this relationship; among Black adults with a college degree, higher network density was inversely associated with BMI. CONCLUSIONS: Our data suggest low educational attainment may reflect more homogenous and less resourceful networks. Multiple pathways are discussed for how education interacts with network density on BMI among Black Americans.

'We need a safe, walkable way to connect our sisters and brothers': a qualitative study of opportunities and challenges for neighborhood-based physical activity among residents of low-income African-American communities.

OBJECTIVE: The purpose of this study was to explore perceptions of the benefits of and influencing factors for neighborhood-based physical activity (PA), and elicit suggestions for increasing neighborhood-based PA among primarily Black residents living in lower income neighborhoods. DESIGN: Eight focus groups were conducted in low-income, predominantly Black neighborhoods (n = 8) in Greenville, SC during Spring 2014. Using a semi-structured focus group guide with open-ended questions, residents were asked to describe benefits of PA, neighborhood factors associated with PA, and ways to increase PA within their neighborhoods. Trained research assistants transcribed audio recordings verbatim. Using grounded theory and an ecological perspective, emergent coding was employed to generate initial categories with open and axial coding used to achieve consensus on themes. RESULTS: Primarily Black (95%), female (72%), and older (M = 61.5 years) residents (N = 76) participated in the study. Seven themes were identified across the three main focus group topics: physical and mental health benefits of neighborhood PA, safety/hazards and social factors as influencing neighborhood PA, and improving safety, structural opportunities, and programing support to improve neighborhood PA. Most participants reported walking within their communities, despite describing several community-level barriers (e.g. drugs, safety). Residents desired structured neighborhood-based opportunities for increasing PA, including walking tracks and walking groups, and reported social benefits to being active, including increased awareness within the community and trust. Participants conveyed that walking strengthened the social environment of their community as well as the health of residents. CONCLUSION: Few studies of contextual factors and PA have focused on African-American, low-income neighborhoods. Despite diverse environmental constraints, residents reported walking within their communities as part of a healthy lifestyle. Social ecological interventions tailored to promote PA and reduce health disparities among residents of low-income communities should highlight neighborhood-based opportunities for PA, focusing on personal and collective social benefits of neighborhood walking.

Loneliness and social isolation among young and late middle-age adults: Associations with personal networks and social participation.

OBJECTIVE: Associations between social networks and loneliness or social isolation are well established among older adults. Yet, limited research examines personal networks and participation on perceived loneliness and social isolation as distinct experiences among younger adults. Accordingly, we explore relationships among objective and subjective measures of personal networks with loneliness and isolation, comparing a younger and older cohort. METHODS: The UC Berkeley Social Networks Study offers unique cohort data on young (21-30 years old, n = 472) and late middle-age adults' (50-70 years old, n = 637) personal network characteristics, social participation, network satisfaction, relationship status, and days lonely and isolated via online survey or in-person interview. Negative binomial regression models were used to examine associations between social network characteristics, loneliness, and isolation by age group. RESULTS: Young adults reported twice as many days lonely and isolated than late middle-age adults, despite, paradoxically, having larger networks. For young adults, informal social participation and weekly religious attendance were associated with fewer days isolated. Among late middle-age adults, number of close kin and relationship status were associated with loneliness. Network satisfaction was associated with fewer days lonely or isolated among both age groups. CONCLUSION: Distinct network characteristics were associated with either loneliness or isolation for each cohort, suggesting network factors are independently associated with each outcome, and may fluctuate over time. Network satisfaction was associated with either loneliness or isolation among both cohorts, suggesting perceptions of social networks may be equally important as objective measures, and remain salient for loneliness and isolation throughout the life course.

A Single Amino Acid Dictates Protein Kinase R Susceptibility to Unrelated Viral Antagonists.

During millions of years of coevolution with their hosts, cytomegaloviruses (CMVs) have succeeded in adapting to overcome host-specific immune defenses, including the protein kinase R (PKR) pathway. Consequently, these adaptations may also contribute to the inability of CMVs to cross species barriers. Here, we provide evidence that the evolutionary arms race between the antiviral factor PKR and its CMV antagonist TRS1 has led to extensive differences in the species-specificity of primate CMV TRS1 proteins. Moreover, we identify a single residue in human PKR that when mutated to the amino acid present in African green monkey (Agm) PKR (F489S) is sufficient to confer resistance to HCMVTRS1. Notably, this precise molecular determinant of PKR resistance has evolved under strong positive selection among primate PKR alleles and is positioned within the αG helix, which mediates the direct interaction of PKR with its substrate eIF2α. Remarkably, this same residue also impacts sensitivity to K3L, a poxvirus-encoded pseudosubstrate that structurally mimics eIF2α. Unlike K3L, TRS1 has no homology to eIF2α, suggesting that unrelated viral genes have convergently evolved to target this critical region of PKR. Despite its functional importance, the αG helix exhibits extraordinary plasticity, enabling adaptations that allow PKR to evade diverse viral antagonists while still maintaining its critical interaction with eIF2α.

Green and lean: Is neighborhood park and playground availability associated with youth obesity? Variations by gender, socioeconomic status, and race/ethnicity.

Parks and park features are important for promoting physical activity and healthy weight, especially for low-income and racial/ethnic minority youth who have disproportionately high obesity rates. This study 1) examined associations between neighborhood park and playground availability and youth obesity, and 2) assessed whether these associations were moderated by youth race/ethnicity and socioeconomic status (SES). In 2013, objectively measured height and weight were collected for all 3rd-5th grade youth (n=13.469) in a southeastern US county to determine body mass index (BMI) percentiles. Enumeration and audits of the county's parks (n=103) were concurrently conducted. Neighborhood park and playground availability were calculated as the number of each facility within or intersecting each youth's Census block group. Multilevel linear regression models were utilized to examine study objectives. For boys, no main effects were detected; however, SES moderated associations such that higher park availability was associated with lower BMI percentile for low-SES youth but higher BMI percentile for high-SES youth. For girls, the number of parks and playgrounds were significantly associated with lower BMI (b=-2.2, b=-1.1, p<0.05, respectively) and race/ethnicity and SES moderated associations between playground availability and BMI percentile. Higher playground availability was associated with lower BMI percentile for White and high-SES girls but higher BMI percentile for African American and low-SES girls. Considerable variation was detected in associations between park and playground availability and youth obesity by SES and race/ethnicity, highlighting the importance of studying the intersection of these characteristics when exploring associations between built environment features and obesity.

Femoral neck-shaft angle and climate-induced body proportions.

OBJECTIVES: Declination in femoral neck-shaft angle (NSA) is commonly linked to an increased level of physical activity during life. More recently, however, research suggests that lower NSA might also be explained, in part, as the mechanical consequence of differences in ecogeographic body proportions. This study tests the proposed link between NSA and climatic-induced body proportions, using relative body mass (RBM), throughout the course of development. MATERIALS AND METHODS: NSA and RBM were collected for 445 immature remains from five geographic locations. NSA and RBM were standardized for age-effects. ANOVA was used to examine when population differences emerged in both NSA and RBM. Regression analyses were used to examine the pattern of relationship between NSA and RBM. RESULTS: Populations differ significantly in NSA and RBM before skeletal maturity, and these differences occur early in life. While both NSA and RBM change over the course of development, no significant relationship was found between NSA and RBM for any sample, or any age category (p = .244). DISCUSSION: Individuals who have relatively greater relative body mass do not necessarily have lower NSA. Population differences in NSA were found to be variable, while differences in RBM remained consistent across the developmental span. Taken together, these results suggest that regardless of body proportions, the degree of declination of NSA is presumed to be similar among individuals with similar gait and ambulatory behaviors. Conversely, populations differ in RBM from birth, and these differences are consistent throughout development. These two measures likely are responsive to diffing stimuli, and any potential relationship is likely complex and multifactorial.

The Influence of Neighborhood Aesthetics, Safety, and Social Cohesion on Perceived Stress in Disadvantaged Communities.

Limited research has explored how specific elements of physical and social environments influence mental health indicators such as perceived stress, or whether such associations are moderated by gender. This study examined the relationship between selected neighborhood characteristics and perceived stress levels within a primarily low-income, older, African-American population in a mid-sized city in the Southeastern U.S. Residents (n = 394; mean age=55.3 years, 70.9% female, 89.3% African American) from eight historically disadvantaged neighborhoods completed surveys measuring perceptions of neighborhood safety, social cohesion, aesthetics, and stress. Multivariate linear regression models examined the association between each of the three neighborhood characteristics and perceived stress. Greater perceived safety, improved neighborhood aesthetics, and social cohesion were significantly associated with lower perceived stress. These associations were not moderated by gender. These findings suggest that improving social attributes of neighborhoods may have positive impacts on stress and related benefits for population health. Future research should examine how neighborhood characteristics influence stress over time.

Longitudinal associations with changes in outdoor recreation area use for physical activity during a community-based intervention.

Outdoor recreation areas (ORA) are important resources for physical activity (PA) and health promotion. While past research has identified correlates of ORA use, few studies have examined predictors of longitudinal changes in park- and trail-based PA in community settings. Using data from a 6-month community-based walking intervention study, we examined cross-sectional and longitudinal predictors of PA in ORAs. Data were collected from baseline and 6-month assessments from participants (n=295) in a group walking intervention in South Carolina; participants enrolled from January 2012-May 2013. A decomposition scheme was used to examine the cross-sectional and longitudinal predictors of average group ORA use for PA, including social support, self-efficacy for PA, perceptions of neighborhood environment, and accelerometer-based PA, adjusting for gender. On average, participants were 49.4+13.3years old, 66.1% were Black, and the majority were women. There was a mean increase in group ORA use of 2.1+0.4days/month from baseline to 6months. Cross-sectionally, higher levels of the percentage of time in MVPA, self-efficacy, and social support were associated with greater group-average ORA use. Longitudinally, increased social support from friends and rating of lighter motorized traffic were associated with increased group ORA use. Additionally, longitudinal increases in percentage of MVPA and more favorable rating of the neighborhood as a place to walk were both associated with decreased group ORA use. Better understanding how social and physical environmental characteristics impact ORA use for PA can lead to more effective intervention strategies and warrants greater attention in future research and public health promotion efforts.

Protein kinase R reveals an evolutionary model for defeating viral mimicry.

Distinguishing self from non-self is a fundamental biological challenge. Many pathogens exploit the challenge of self discrimination by employing mimicry to subvert key cellular processes including the cell cycle, apoptosis and cytoskeletal dynamics. Other mimics interfere with immunity. Poxviruses encode K3L, a mimic of eIF2alpha, which is the substrate of protein kinase R (PKR), an important component of innate immunity in vertebrates. The PKR-K3L interaction exemplifies the conundrum imposed by viral mimicry. To be effective, PKR must recognize a conserved substrate (eIF2alpha) while avoiding rapidly evolving substrate mimics such as K3L. Using the PKR-K3L system and a combination of phylogenetic and functional analyses, we uncover evolutionary strategies by which host proteins can overcome mimicry. We find that PKR has evolved under intense episodes of positive selection in primates. The ability of PKR to evade viral mimics is partly due to positive selection at sites most intimately involved in eIF2alpha recognition. We also find that adaptive changes on multiple surfaces of PKR produce combinations of substitutions that increase the odds of defeating mimicry. Thus, although it can seem that pathogens gain insurmountable advantages by mimicking cellular components, host factors such as PKR can compete in molecular 'arms races' with mimics because of evolutionary flexibility at protein interaction interfaces challenged by mimicry.

Predicting outdoor recreation area use in a Southeastern US county: a signal detection analysis.

Use of outdoor recreation areas (ORAs) is correlated with physical activity (PA) in community-dwelling adults. Additionally, the wide spread availability of ORAs, including their placement in disadvantaged neighborhoods, make them an especially promising venue through which to promote PA. The purpose of this study was to examine the combination of individual-level factors associated with ORA use in a socioeconomically diverse Southeastern US county. A 2011 random digit-dial survey included 829 adults aged 18+ years with complete data; questions assessed PA level and use/perceived safety of ORAs. Signal detection analysis, a non-parametric recursive partitioning technique, identified cutpoints for defining subgroups of respondents based on ORA use. Seven subgroups were defined ranging from 77.2 % ORA use (younger, met PA recommendations) to 31.8 % ORA use (older, perceived ORAs to be less safe). Signal detection did not identify gender or race as important for defining subgroups. Results suggest that gendered and ethnically-focused ORA promotion campaigns might be unnecessary. Instead, efforts could focus on increasing awareness of ORA facilities among older, less active adults.

Factors associated with active commuting to work among women.

Active commuting (AC), the act of walking or biking to work, has notable health benefits though rates of AC remain low among women. This study used a social-ecological framework to examine the factors associated with AC among women. A convenience sample of employed, working women (n = 709) completed an online survey about their mode of travel to work. Individual, interpersonal, institutional, community, and environmental influences were assessed. Basic descriptive statistics and frequencies described the sample. Simple logistic regression models examined associations with the independent variables with AC participation and multiple logistic regression analysis determined the relative influence of social ecological factors on AC participation. The sample was primarily middle-aged (44.09±11.38 years) and non-Hispanic White (92%). Univariate analyses revealed several individual, interpersonal, institutional, community and environmental factors significantly associated with AC. The multivariable logistic regression analysis results indicated that significant factors associated with AC included number of children, income, perceived behavioral control, coworker AC, coworker AC normative beliefs, employer and community supports for AC, and traffic. The results of this study contribute to the limited body of knowledge on AC participation for women and may help to inform gender-tailored interventions to enhance AC behavior and improve health.

Species specificity of protein kinase r antagonism by cytomegalovirus TRS1 genes.

The host antiviral protein kinase R (PKR) has rapidly evolved during primate evolution, likely in response to challenges posed by many different viral antagonists, such as the TRS1 gene of cytomegaloviruses (CMVs). In turn, viral antagonists have adapted to changes in PKR. As a result of this "arms race," modern TRS1 alleles in CMVs may function differently in cells derived from alternative species. We have previously shown that human CMV TRS1 (HuTRS1) blocks the PKR pathway and rescues replication of a vaccinia virus mutant lacking its major PKR antagonist in human cells. We now demonstrate that HuTRS1 does not have these activities in Old World monkey cells. Conversely, the rhesus cytomegalovirus homologue of HuTRS1 (RhTRS1) fulfills these functions in African green monkey cells, but not rhesus or human cells. Both TRS1 proteins bind to double-stranded RNA and, in the cell types in which they can rescue VVΔE3L replication, they also bind to PKR and prevent phosphorylation of the α-subunit of eukaryotic initiation factor 2. However, while HuTRS1 binds to inactive human PKR and prevents its autophosphorylation, RhTRS1 binds to phosphorylated African green monkey PKR. These studies reveal that evolutionary adaptations in this critical host defense protein have altered its binding interface in a way that has resulted in a qualitatively altered mechanism of PKR antagonism by viral TRS1 alleles from different CMVs. These results suggest that PKR antagonism is likely one of the factors that contributes to species specificity of cytomegalovirus replication.

Differences in youth and adult physical activity in park settings by sex and race/ethnicity.

We examined differences by sex and race/ethnicity in the observed moderate- to vigorous-intensity physical activity (MVPA) of youth and adults in diverse areas of 4 parks in Kansas City, Missouri, in 2009. Male youth were more active on playgrounds and pools or splashpads than female youth. White youth were less active than nonwhite youth in open spaces and on paved trails. Male adults were more active in open spaces than female adults, and white adults were more active on paved trails than nonwhite adults. Understanding variations in MVPA between user groups can inform park design efforts to foster increased activity among all visitors.