Transcriptional suppression of sphingolipid catabolism controls pathogen resistance in C. elegans.

Sphingolipids are required for diverse biological functions and are degraded by specific catabolic enzymes. However, the mechanisms that regulate sphingolipid catabolism are not known. Here we characterize a transcriptional axis that regulates sphingolipid breakdown to control resistance against bacterial infection. From an RNAi screen for transcriptional regulators of pathogen resistance in the nematode C. elegans, we identified the nuclear hormone receptor nhr-66, a ligand-gated transcription factor homologous to human hepatocyte nuclear factor 4. Tandem chromatin immunoprecipitation-sequencing and RNA sequencing experiments revealed that NHR-66 is a transcriptional repressor, which directly targets sphingolipid catabolism genes. Transcriptional de-repression of two sphingolipid catabolic enzymes in nhr-66 loss-of-function mutants drives the breakdown of sphingolipids, which enhances host susceptibility to infection with the bacterial pathogen Pseudomonas aeruginosa. These data define transcriptional control of sphingolipid catabolism in the regulation of cellular sphingolipids, a process that is necessary for pathogen resistance.

Protocol to assess receptor-ligand binding in C. elegans using adapted thermal shift assays.

The Caenorhabditis elegans genome encodes a greatly expanded number of nuclear hormone receptors, many of which remain orphaned. Here, we present a protocol to assess ligand-receptor binding in C. elegans using an adapted cellular thermal shift assay and isothermal dose response. We describe steps for growing C. elegans and preparing lysates and compounds. We also detail how to perform and quantify these assays. This protocol can be used to study any soluble receptor. For complete details on the use and execution of this protocol, please refer to Peterson et al. (2023).1.

Non-canonical pattern recognition of a pathogen-derived metabolite by a nuclear hormone receptor identifies virulent bacteria in C. elegans.

Distinguishing infectious pathogens from harmless microorganisms is essential for animal health. The mechanisms used to identify infectious microbes are not fully understood, particularly in metazoan hosts that eat bacteria as their food source. Here, we characterized a non-canonical pattern-recognition system in Caenorhabditis elegans (C. elegans) that assesses the relative threat of virulent Pseudomonas aeruginosa (P. aeruginosa) to activate innate immunity. We discovered that the innate immune response in C. elegans was triggered by phenazine-1-carboxamide (PCN), a toxic metabolite produced by pathogenic strains of P. aeruginosa. We identified the nuclear hormone receptor NHR-86/HNF4 as the PCN sensor in C. elegans and validated that PCN bound to the ligand-binding domain of NHR-86/HNF4. Activation of NHR-86/HNF4 by PCN directly engaged a transcriptional program in intestinal epithelial cells that protected against P. aeruginosa. Thus, a bacterial metabolite is a pattern of pathogenesis surveilled by nematodes to identify a pathogen in its bacterial diet.

A Scoping Review of Treatment Outcome Measures for Vulvar Intraepithelial Neoplasia.

OBJECTIVE: The goal of this study is to identify a list of clinician-reported outcome measures (CROMs) and patient-reported outcome measures (PROMs) through a review of published studies reporting on any therapeutic interventions for vulvar intraepithelial neoplasia (VIN). MATERIALS AND METHODS: A systematic search of published studies reporting on any therapeutic interventions for VIN was performed on MEDLINE, Embase, Cochrane Database, PsychInfo, and CINAHL from inception to September 20, 2021, based on predetermined study selection criteria. Data were extracted and analyzed by 2 authors independently using Covidence software. RESULTS: Thirty two of 2386 studies identified met study selection criteria. None of the 32 studies provided an explicit definition of VIN treatment "success." The most common CROM was "clinical response to treatment." The most common scale used to measure this outcome was "complete response/partial response/no response"; however, 17 of 23 studies (73.9%) did not define these values. Laboratory CROMs were reported in 12/32 (37.5%) studies. Patient-reported outcome measures were reported in only 10 of 32 studies(31.3%) -the most common PROM was "symptoms." Only 2 of 32 studies measured PROMs related to "quality of life" domains. Adverse events/treatment-related adverse effects were reported in 24 of 32 studies (75%), although 71% of studies provided no details on how these data were collected. CONCLUSIONS: There is a large variation in outcome measures, instruments, and scales used for any clinician-reported treatment outcome such as "clinical response." Most studies do not include patient-reported outcome measures assessing quality of life domains. A Core Outcome Set for the treatment of VIN is needed to improve the quality of VIN research.

A Systematic Review of Risk Factors for Development, Recurrence, and Progression of Vulvar Intraepithelial Neoplasia.

OBJECTIVE: Vulvar intraepithelial neoplasia (VIN) is a premalignant condition with high recurrence rates despite treatment. Vulvar intraepithelial neoplasia develops through separate etiologic pathways relative to the presence or absence of human papillomavirus (HPV) and TP53 mutations. This systematic review was conducted (1) to identify historical risk factors for the development, recurrence, and progression of VIN and (2) to critique these risk factors in the context of advances made in the stratification of VIN based on HPV or TP53 status. MATERIALS AND METHODS: A systematic search was performed on MEDLINE, Embase, Cochrane Database, PsychInfo, and CINAHL from inception to July 5, 2021. Three gynecologic oncologists independently evaluated the eligibility of studies based on predetermined inclusion and exclusion criteria, abstracted data, and then analyzed the relevant data. RESULTS: A total of 1,969 studies (involving 6,983 patients) were identified. Twenty-nine studies met inclusion criteria. The quality of evidence was low; primarily level 2b (Oxford Centre for Evidence-Based Medicine). Risk factors associated with the development of VIN include: smoking and coexisting vulvar dermatoses. Risk factors associated with recurrence include: smoking, multifocal disease, and positive surgical margins. Recent studies identified the presence of differentiated VIN/TP53 mutation as the most significant risk factor for both VIN recurrence and malignant progression. CONCLUSIONS: The current body of evidence consists primarily of small retrospective observational studies. Well-designed retrospective case-control series and/or prospective observational studies are urgently needed. Ideally, future studies will collect standardized data regarding associated risk factors and stratify women with VIN based on HPV and TP53 status.

Pegylated Interferon-α-Induced Natural Killer Cell Activation Is Associated With Human Immunodeficiency Virus-1 DNA Decline in Antiretroviral Therapy-Treated HIV-1/Hepatitis C Virus-Coinfected Patients.

Background: Interferon alpha (IFN-α) can potently reduce human immunodeficiency virus type 1 (HIV-1) replication in tissue culture and animal models, but may also modulate residual viral reservoirs that persist despite suppressive antiretroviral combination therapy. However, mechanisms leading to viral reservoir reduction during IFN-α treatment are unclear. Methods: We analyzed HIV-1 gag DNA levels in CD4 T cells by digital droplet polymerase chain reaction and CD8 T-cell and natural killer (NK) cell phenotypes by flow cytometry in a cohort of antiretroviral therapy-treated HIV-1/hepatitis C virus-coinfected patients (n = 67) undergoing treatment for hepatitis C infection with pegylated IFN-α and ribavirin for an average of 11 months. Results: We observed that IFN-α treatment induced a significant decrease in CD4 T-cell counts (P < .0001), in CD4 T-cell-associated HIV-1 DNA copies (P = .002) and in HIV-1 DNA copies per microliter of blood (P < .0001) in our study patients. Notably, HIV-1 DNA levels were unrelated to HIV-1-specific CD8 T-cell responses. In contrast, proportions of total NK cells, CD56brightCD16- NK cells, and CD56brightCD16+ NK cells were significantly correlated with reduced levels of CD4 T-cell-associated HIV-1 DNA during IFN-α treatment, especially when coexpressing the activation markers NKG2D and NKp30. Conclusions: These data suggest that the reduction of viral reservoir cells during treatment with IFN-α is primarily attributable to antiviral activities of NK cells.

Transcriptional Changes during Naturally Acquired Zika Virus Infection Render Dendritic Cells Highly Conducive to Viral Replication.

Although dendritic cells are among the human cell population best equipped for cell-intrinsic antiviral immune defense, they seem highly susceptible to infection with the Zika virus (ZIKV). Using highly purified myeloid dendritic cells isolated from individuals with naturally acquired acute infection, we here show that ZIKV induces profound perturbations of transcriptional signatures relative to healthy donors. Interestingly, we noted a remarkable downregulation of antiviral interferon-stimulated genes and innate immune sensors, suggesting that ZIKV can actively suppress interferon-dependent immune responses. In contrast, several host factors known to support ZIKV infection were strongly upregulated during natural ZIKV infection; these transcripts included AXL, the main entry receptor for ZIKV; SOCS3, a negative regulator of ISG expression; and IDO-1, a recognized inducer of regulatory T cell responses. Thus, during in vivo infection, ZIKV can transform the transcriptome of dendritic cells in favor of the virus to render these cells highly conducive to ZIKV infection.

HLA-G+ HIV-1-specific CD8+ T cells are associated with HIV-1 immune control.

OBJECTIVE(S): To assess the frequency and function of HIV-1-specific HLA-G (histocompatibility antigen class I, G) CD8 T cells in HIV-1 controllers and progressors. DESIGN: We performed an observational cross-sectional cohort analysis in untreated (n = 47) and treated (n = 17) HIV-1 patients with different rates of disease progression and n = 14 healthy individuals. METHODS: We evaluated the frequency, the proportion and the function of total and virus-specific HLA-G CD8 T cells by tetramer or intracellular cytokine staining, followed by flow cytometric analysis. Cytokine secretion of sorted CD8 T-cell subsets was evaluated by Luminex assays. RESULTS: The proportion and the absolute frequency of HLA-G HIV-1-specific CD8 T cells were directly associated with CD4 T-cell counts and inversely correlated with viral loads, whereas total or HLA-G-negative HIV-1-specific CD8 T cells were not. In functional assays, HLA-G CD8 T cells from HIV-1-negative individuals had higher abilities to produce the antiviral (C-C chemokine receptor type 5) ligands MIP-1ß (macrophage inflammatory protein-1ß), MIP-1α and Rantes. CONCLUSION: HLA-G HIV-1-specific CD8 T cells may represent a previously unrecognized correlate of HIV-1 immune control.

Anti-α4 antibody treatment blocks virus traffic to the brain and gut early, and stabilizes CNS injury late in infection.

Four SIV-infected monkeys with high plasma virus and CNS injury were treated with an anti-α4 blocking antibody (natalizumab) once a week for three weeks beginning on 28 days post-infection (late). Infection in the brain and gut were quantified, and neuronal injury in the CNS was assessed by MR spectroscopy, and compared to controls with AIDS and SIV encephalitis. Treatment resulted in stabilization of ongoing neuronal injury (NAA/Cr by 1H MRS), and decreased numbers of monocytes/macrophages and productive infection (SIV p28+, RNA+) in brain and gut. Antibody treatment of six SIV infected monkeys at the time of infection (early) for 3 weeks blocked monocyte/macrophage traffic and infection in the CNS, and significantly decreased leukocyte traffic and infection in the gut. SIV - RNA and p28 was absent in the CNS and the gut. SIV DNA was undetectable in brains of five of six early treated macaques, but proviral DNA in guts of treated and control animals was equivalent. Early treated animals had low-to-no plasma LPS and sCD163. These results support the notion that monocyte/macrophage traffic late in infection drives neuronal injury and maintains CNS viral reservoirs and lesions. Leukocyte traffic early in infection seeds the CNS with virus and contributes to productive infection in the gut. Leukocyte traffic early contributes to gut pathology, bacterial translocation, and activation of innate immunity.