Transitional dendritic cells are distinct from conventional DC2 precursors and mediate proinflammatory antiviral responses
High-dimensional approaches have revealed heterogeneity amongst dendritic cells (DCs), including a population of transitional DCs (tDCs) in mice and humans. However, the origin and relationship of tDCs to other DC subsets has been unclear. Here we show that tDCs are distinct from other well-characterized DCs and conventional DC precursors (pre-cDCs). We demonstrate that tDCs originate from bone marrow progenitors shared with plasmacytoid DCs (pDCs). In the periphery, tDCs contribute to the pool of ESAM+ type 2 DCs (DC2s), and these DC2s have pDC-related developmental features. Different from pre-cDCs, tDCs have less turnover, capture antigen, respond to stimuli and activate antigen-specific naïve T cells, all characteristics of differentiated DCs. Different from pDCs, viral sensing by tDCs results in IL-1β secretion and fatal immune pathology in a murine coronavirus model. Our findings suggest that tDCs are a distinct pDC-related subset with a DC2 differentiation potential and unique proinflammatory function during viral infections.
Vision 2020: How Caregiving and Work Productivity Outlook Shifted for Academic Pediatric Faculty
An Objective System for Quantitative Assessment of Television Viewing Among Children (Family Level Assessment of Screen Use in the Home-Television): System Development Study
BACKGROUND:Television viewing among children is associated with developmental and health outcomes, yet measurement techniques for television viewing are prone to errors, biases, or both. OBJECTIVE:This study aims to develop a system to objectively and passively measure children's television viewing time. METHODS:The Family Level Assessment of Screen Use in the Home-Television (FLASH-TV) system includes three sequential algorithms applied to video data collected in front of a television screen: face detection, face verification, and gaze estimation. A total of 21 families of diverse race and ethnicity were enrolled in 1 of 4 design studies to train the algorithms and provide proof of concept testing for the integrated FLASH-TV system. Video data were collected from each family in a laboratory mimicking a living room or in the child's home. Staff coded the video data for the target child as the gold standard. The accuracy, sensitivity, specificity, positive predictive value, and negative predictive value were calculated for each algorithm, as compared with the gold standard. Prevalence and biased adjusted Îº scores and an intraclass correlation using a generalized linear mixed model compared FLASH-TV's estimation of television viewing duration to the gold standard. RESULTS:FLASH-TV demonstrated high sensitivity for detecting faces (95.5%-97.9%) and performed well on face verification when the child's gaze was on the television. Each of the metrics for estimating the child's gaze on the screen was moderate to good (range: 55.1% negative predictive value to 91.2% specificity). When combining the 3 sequential steps, FLASH-TV estimation of the child's screen viewing was overall good, with an intraclass correlation for an overall time watching television of 0.725 across conditions. CONCLUSIONS:FLASH-TV offers a critical step forward in improving the assessment of children's television viewing.
Autoantibody-mediated impairment of DNASE1L3 activity in sporadic systemic lupus erythematosus
Antibodies to double-stranded DNA (dsDNA) are prevalent in systemic lupus erythematosus (SLE), particularly in patients with lupus nephritis, yet the nature and regulation of antigenic cell-free DNA (cfDNA) are poorly understood. Null mutations in the secreted DNase DNASE1L3 cause human monogenic SLE with anti-dsDNA autoreactivity. We report that >50% of sporadic SLE patients with nephritis manifested reduced DNASE1L3 activity in circulation, which was associated with neutralizing autoantibodies to DNASE1L3. These patients had normal total plasma cfDNA levels but showed accumulation of cfDNA in circulating microparticles. Microparticle-associated cfDNA contained a higher fraction of longer polynucleosomal cfDNA fragments, which bound autoantibodies with higher affinity than mononucleosomal fragments. Autoantibodies to DNASE1L3-sensitive antigens on microparticles were prevalent in SLE nephritis patients and correlated with the accumulation of cfDNA in microparticles and with disease severity. DNASE1L3-sensitive antigens included DNA-associated proteins such as HMGB1. Our results reveal autoantibody-mediated impairment of DNASE1L3 activity as a common nongenetic mechanism facilitating anti-dsDNA autoreactivity in patients with severe sporadic SLE.
Human plasmacytoid dendritic cells mount a distinct antiviral response to virus-infected cells
Plasmacytoid dendritic cells (pDCs) can rapidly produce interferons and other soluble factors in response to extracellular viruses or virus mimics such as CpG-containing DNA. pDCs can also recognize live cells infected with certain RNA viruses, but the relevance and functional consequences of such recognition remain unclear. We studied the response of primary DCs to the prototypical persistent DNA virus, human cytomegalovirus (CMV). Human pDCs produced high amounts of type I interferon (IFN-I) when incubated with live CMV-infected fibroblasts but not with free CMV; the response involved integrin-mediated adhesion, transfer of DNA-containing virions to pDCs, and the recognition of DNA through TLR9. Compared with transient polyfunctional responses to CpG or free influenza virus, pDC response to CMV-infected cells was long-lasting, dominated by the production of IFN-I and IFN-III, and lacked diversification into functionally distinct populations. Similarly, pDC activation by influenza-infected lung epithelial cells was highly efficient, prolonged, and dominated by interferon production. Prolonged pDC activation by CMV-infected cells facilitated the activation of natural killer cells critical for CMV control. Last, patients with CMV viremia harbored phenotypically activated pDCs and increased circulating IFN-I and IFN-III. Thus, recognition of live infected cells is a mechanism of virus detection by pDCs that elicits a unique antiviral immune response.
PapÃ¡s Saludables, NiÃ±os Saludables: Perspectives From Hispanic Parents and Children in a Culturally Adapted Father-Focused Obesity Program
OBJECTIVE:Qualitatively assess culturally adapted lifestyle intervention, PapÃ¡s Saludables, NiÃ±os Saludables (PSNS; Healthy Dads, Healthy Kids), for Hispanic fathers and children. METHODS:Semistructured interviews of parents and children after participation in 10-week PSNS program for Hispanic fathers and children. Qualitative data double-coded inductively and deductively until consensus reached. RESULTS:Total of 26 fathers, 26 mothers, and 45 children interviewed. Parents and children had positive feedback about program content on culturally relevant nutrition and physical activity and reported improved father-child bonding. Mothers noted increased involvement among fathers in child's well-being. Participants suggested lengthening the program. CONCLUSIONS AND IMPLICATIONS:PapÃ¡s Saludables, NiÃ±os Saludables is an innovative approach with promise in engaging Hispanic fathers and children in a lifestyle program that emphasizes the role of fathers in children's lifestyle behaviors. Familism, respeto (respect), and promoting father-child relationships were important to engage fathers. Results from this study will inform future trials of PSNS and help identify ways to increase engagement of Hispanic men in other programs.
miR-29 Sustains B Cell Survival and Controls Terminal Differentiation via Regulation of PI3K Signaling
The phosphatidylinositol 3-kinase (PI3K) signaling cascade downstream of the B cell receptor (BCR) signalosome is essential for B cell maturation. Proper signaling strength is maintained through the PI3K negative regulator phosphatase and tensin homolog (PTEN). Although a role for microRNA (miRNA)-dependent control of the PTEN-PI3K axis has been described, the contribution of individual miRNAs to the regulation of this crucial signaling modality in mature B lymphocytes remains to be elucidated. Our analyses reveal that ablation of miR-29 specifically in B lymphocytes results in an increase in PTEN expression and dampening of the PI3K pathway in mature B cells. This dysregulation has a profound impact on the survival of B lymphocytes and results in increased class switch recombination and decreased plasma cell differentiation. Furthermore, we demonstrate that ablation of one copy of Pten is sufficient to ameliorate the phenotypes associated with miR-29 loss. Our data suggest a critical role for the miR-29-PTEN-PI3K regulatory axis in mature B lymphocytes.
Feasibility of Targeting Hispanic Fathers and Children in an Obesity Intervention: PapÃ¡s Saludables NiÃ±os Saludables
Plasmacytoid Dendritic Cells and Type I Interferon Promote Extrafollicular B Cell Responses to Extracellular Self-DNA
Class-switched antibodies to double-stranded DNA (dsDNA) are prevalent and pathogenic in systemic lupus erythematosus (SLE), yet mechanisms of their development remain poorly understood. Humans and mice lacking secreted DNase DNASE1L3 develop rapid anti-dsDNA antibody responses and SLE-like disease. We report that anti-DNA responses in Dnase1l3-/- mice require CD40L-mediated TÂ cell help, but proceed independently of germinal center formation via short-lived antibody-forming cells (AFCs) localized to extrafollicular regions. Type I interferon (IFN-I) signaling and IFN-I-producing plasmacytoid dendritic cells (pDCs) facilitate the differentiation of DNA-reactive AFCs inÂ vivo and inÂ vitro and are required for downstream manifestations of autoimmunity. Moreover, the endosomal DNA sensor TLR9 promotes anti-dsDNA responses and SLE-like disease in Dnase1l3-/- mice redundantly with another nucleic acid-sensing receptor, TLR7. These results establish extrafollicular B cell differentiation into short-lived AFCs as a key mechanism of anti-DNA autoreactivity and reveal a major contribution of pDCs, endosomal Toll-like receptors (TLRs), and IFN-I to this pathway.
Cultural adaptation of 'Healthy Dads, Healthy Kids' for Hispanic families: applying the ecological validity model
BACKGROUND:Healthy Dads Healthy Kids (HDHK) is a unique lifestyle obesity intervention for fathers and children that demonstrated weight loss among the fathers and behavior change among fathers and children in Australia. The program is gender-tailored to specifically target fathers for weight loss and 5-12â€‰year old children for obesity prevention. The aim of this formative study was to examine an Expert Panel's and Hispanic Family Panel's perceptions about the program and suggestions for the cultural adaptation of HDHK for Hispanic families in southwestern US. METHODS:Forty-four Hispanic participants (22 fathers, 13 mothers and 9 children) made up the Family Panel. They participated in 1-5 study contacts (focus groups, online survey, and/or interviews). The scripts and qualitative guides assessed participants' perceptions of the HDHK content and material using the Ecological Validity Model. Studies were conducted in English or Spanish, depending on the preference of the participant. Focus groups and interviews were audio-recorded, transcribed, translated, and thematically coded. Findings were reviewed with the Expert Panel who helped inform the cultural adaptation. RESULTS:80% of parents were foreign-born, 57% spoke only Spanish at home, and 60% did not graduate from high school. Several themes emerged to inform the cultural adaptation of the program. Parents agreed with the HDHK goals and recommended the program place greater emphasis on parenting and limiting children's screen time. Some mothers and fathers wanted greater mother engagement. Weekly videos and a Facebook group emerged as favorite alternative options to engage mothers. Greater promotion of familism (inclusion and impact on whole family) was recommended for the program goals and activities. Gender roles for mothers and fathers, and differences in how fathers interact with male and female children, emerged and should be considered in program activities. Several barriers to father engagement surfaced, including lack of time due to work schedules, physically demanding jobs, concerns of caring for children without mother, fathers' current fitness/weight, and lack of knowledge of how to eat more healthfully. The reading level of the HDHK materials was too high for some parents. CONCLUSION:Findings from these formative qualitative studies informed the cultural adaptation of HDHK for Hispanic families, to account for literacy level, cultural values, and barriers to participation and engagement.