Faculty Bibliography

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 T 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 in vivo and in 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.

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 5-12 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.

Tissue-resident macrophages are a diverse population of cells that perform specialized functions including sustaining tissue homeostasis and tissue surveillance. Here, we report an interstitial subset of CD169⁺ lung-resident macrophages that are transcriptionally and developmentally distinct from alveolar macrophages (AMs). They are primarily localized around the airways and are found in close proximity to the sympathetic nerves in the bronchovascular bundle. These nerve- and airway-associated macrophages (NAMs) are tissue resident, yolk sac derived, self-renewing, and do not require CCR2⁺ monocytes for development or maintenance. Unlike AMs, the development of NAMs requires CSF1 but not GM-CSF. Bulk population and single-cell transcriptome analysis indicated that NAMs are distinct from other lung-resident macrophage subsets and highly express immunoregulatory genes under steady-state and inflammatory conditions. NAMs proliferated robustly after influenza infection and activation with the TLR3 ligand poly(I:C), and in their absence, the inflammatory response was augmented, resulting in excessive production of inflammatory cytokines and innate immune cell infiltration. Overall, our study provides insights into a distinct subset of airway-associated pulmonary macrophages that function to maintain immune and tissue homeostasis.

Plasmacytoid dendritic cells (pDCs) are sensor cells with diverse immune functions, from type I interferon (IFN-I) production to antigen presentation, T cell activation, and tolerance. Regulation of these functions remains poorly understood but could be mediated by functionally specialized pDC subpopulations. We address pDC diversity using a high-dimensional single-cell approach: mass cytometry (CyTOF). Our analysis uncovers a murine pDC-like population that specializes in antigen presentation with limited capacity for IFN-I production. Using a multifaceted cross-species comparison, we show that this pDC-like population is the definitive murine equivalent of the recently described human AXL⁺ DCs, which we unify under the name transitional DCs (tDCs) given their continuum of pDC and cDC2 characteristics. tDCs share developmental traits with pDCs, as well as recruitment dynamics during viral infection. Altogether, we provide a framework for deciphering the function of pDCs and tDCs during diseases, which has the potential to open new avenues for therapeutic design.

This paper explores culturally-related concerns that arose during a multi-year study of obsessive-compulsive disorder (OCD) along the U.S.-Mexico border and describes adaptations made to better connect the research process to study participants. The purpose of this exploration is two-fold: (1) to offer suggestions for culturally sensitive borderland mental health research; and (2) to enhance dialog focused on culture, mental health research and the U.S.-Mexico border. Systematic coding of the written record of weekly research team meetings identified six recurring cultural concerns: emotionally charged and poorly understood terminology; differing meanings of ethnicity and acculturation; quality of life-regional variation and uncertainty; overlap of research and care; hopeful but hesitant; and fatalism. We conclude that diligence in the initial planning phase of a study is only part of the challenge in doing culturally sensitive research. Equally important is an ongoing process of evaluation to make explicit cultural concerns that arise during research, as well as a readiness to implement culturally sensitive research adaptations.

An IRF8-dependent subset of conventional dendritic cells (cDCs), termed cDC1, effectively cross-primes CD8⁺ T cells and facilitates tumor-specific T cell responses. Etv6 is an ETS family transcription factor that controls hematopoietic stem and progenitor cell (HSPC) function and thrombopoiesis. We report that like HSPCs, cDCs express Etv6, but not its antagonist, ETS1, whereas interferon-producing plasmacytoid dendritic cells (pDCs) express both factors. Deletion of Etv6 in the bone marrow impaired the generation of cDC1-like cells in vitro and abolished the expression of signature marker CD8α on cDC1 in vivo. Moreover, Etv6-deficient primary cDC1 showed a partial reduction of cDC-specific and cDC1-specific gene expression and chromatin signatures and an aberrant up-regulation of pDC-specific signatures. Accordingly, DC-specific Etv6 deletion impaired CD8⁺ T cell cross-priming and the generation of tumor antigen-specific CD8⁺ T cells. Thus, Etv6 optimizes the resolution of cDC1 and pDC expression programs and the functional fitness of cDC1, thereby facilitating T cell cross-priming and tumor-specific responses.

PURPOSE OF REVIEW:There is a growing evidence of the important role that fathers play in influencing their children's eating and other weight-related behaviors. Latino children are at high risk for obesity and associated medical conditions. Engaging Latino fathers is a potentially important and unique way to help promote healthy lifestyles for Latino children, but doing so requires a culturally sensitive understanding both of fathers' current role and the family perceptions of this role. RECENT FINDINGS:Here, we review recent data and argue that there are subtle but important differences between the qualitative and quantitative research conducted regarding the role Latino fathers may play in promoting healthy eating and physical activity for their children. We suggest how to synthesize these findings and also present qualitative results for ways to best engage Latino fathers in research studies with a focus on physical activity. Results from the review support that Latino fathers are important potential targets for child obesity prevention, but our findings stress the importance of considering cultural values when trying to recruit, engage and retain Latino fathers for such research.

The spleen is an important site for generating protective immune responses against pathogens. After infection, immune cells undergo rapid reorganization to initiate and maintain localized inflammatory responses; however, the mechanisms governing this spatial and temporal cellular reorganization remain unclear. We show that the strategic position of splenic marginal zone CD169⁺ macrophages is vital for rapid initiation of antibacterial responses. In addition to controlling initial bacterial growth, CD169⁺ macrophages orchestrate a second phase of innate protection by mediating the transport of bacteria to splenic T cell zones. This compartmentalization of bacteria within the spleen was essential for driving the reorganization of innate immune cells into hierarchical clusters and for local interferon-γ production near sites of bacterial replication foci. Our results show that both phases of the antimicrobial innate immune response were dependent on CD169⁺ macrophages, and, in their absence, the series of events needed for pathogen clearance and subsequent survival of the host was disrupted. Our study provides insight into how lymphoid organ structure and function are related at a fundamental level.

The presence of tumor-infiltrating CD8(+) T cells is associated with tumor regression and better prognosis. Cytomegalovirus (CMV) infection elicits a robust and long-lasting CD8(+) T-cell response, which makes CMV a potentially promising vaccine vector against cancer. In the current study, we used recombinant murine CMV (MCMV) strains as prophylactic and therapeutic vaccines in an aggressive B16 lung metastatic melanoma model. Immunization with MCMV-expressing ovalbumin (OVA) induced a potent OVA-specific CD8(+) T-cell response and was effective in protecting mice from OVA-expressing B16 melanoma in an antigen-dependent manner. We engineered MCMV to express a modified B16 melanoma antigen gp100 (MCMV-gp100KGP). Immunization with MCMV-gp100KGP was highly effective in overcoming immune tolerance to self-antigen and induced a strong, long-lasting gp100-specific CD8(+) T-cell response even in the presence of preexisting anti-CMV immunity. Furthermore, both prophylactic and therapeutic vaccinations of mice with MCMV-gp100KGP effectively protected mice from highly aggressive lung B16-F10 melanoma, and the protection was mediated by gp100-specific CD8(+) T cells. We showed that MCMV is a superior vaccine vector compared with a commonly used vesicular stomatitis virus vector. Collectively, our studies demonstrate that CMV is a promising vaccine vector to prevent and treat tumors.

Ixodes scapularis, the black-legged tick, vectors several human pathogens including Borrelia burgdorferi, the agent of Lyme disease in North America. Pathogen transmission to the vertebrate host occurs when infected ticks feed on the mammalian host to obtain a blood meal. Efforts to understand how the tick confronts host hemostatic mechanisms and imbibes a fluid blood meal have largely focused on the anticoagulation strategies of tick saliva. The blood meal that enters the tick gut remains in a fluid state for several days during the process of feeding, and the role of the tick gut in maintaining the blood-meal fluid is not understood. We now demonstrate that the tick gut produces a potent inhibitor of thrombin, a key enzyme in the mammalian coagulation cascade. Chromatographic fractionation of engorged tick gut proteins identified one predominant thrombin inhibitory activity associated with an approximately 18 kDa protein, henceforth referred to as Ixophilin. The ixophilin gene was preferentially transcribed in the guts of feeding nymphs. Expression began after 24 hours of feeding, coincident with the flow of host blood into the tick gut. Immunity against Ixophilin delayed tick feeding, and decreased feeding efficiency significantly. Surprisingly, immunity against Ixophilin resulted in increased Borrelia burgdorferi transmission to the host, possibly due to delayed feeding and increased transmission opportunity. These observations illuminate the potential drawbacks of targeting individual tick proteins in a functional suite. They also underscore the need to identify the "anticoagulome" of the tick gut, and to prioritize a critical subset of anticoagulants that could be targeted to efficiently thwart tick feeding, and block pathogen transmission to the vertebrate host.