SoxF factors induce Notch1 expression via direct transcriptional regulation during early arterial development.

Arterial specification and differentiation are influenced by a number of regulatory pathways. While it is known that the Vegfa-Notch cascade plays a central role, the transcriptional hierarchy controlling arterial specification has not been fully delineated. To elucidate the direct transcriptional regulators of Notch receptor expression in arterial endothelial cells, we used histone signatures, DNaseI hypersensitivity and ChIP-seq data to identify enhancers for the human NOTCH1 and zebrafish notch1b genes. These enhancers were able to direct arterial endothelial cell-restricted expression in transgenic models. Genetic disruption of SoxF binding sites established a clear requirement for members of this group of transcription factors (SOX7, SOX17 and SOX18) to drive the activity of these enhancers in vivo Endogenous deletion of the notch1b enhancer led to a significant loss of arterial connections to the dorsal aorta in Notch pathway-deficient zebrafish. Loss of SoxF function revealed that these factors are necessary for NOTCH1 and notch1b enhancer activity and for correct endogenous transcription of these genes. These findings position SoxF transcription factors directly upstream of Notch receptor expression during the acquisition of arterial identity in vertebrates.

Differential oestrogen receptor binding is associated with clinical outcome in breast cancer.

Oestrogen receptor-α (ER) is the defining and driving transcription factor in the majority of breast cancers and its target genes dictate cell growth and endocrine response, yet genomic understanding of ER function has been restricted to model systems. Here we map genome-wide ER-binding events, by chromatin immunoprecipitation followed by high-throughput sequencing (ChIP-seq), in primary breast cancers from patients with different clinical outcomes and in distant ER-positive metastases. We find that drug-resistant cancers still recruit ER to the chromatin, but that ER binding is a dynamic process, with the acquisition of unique ER-binding regions in tumours from patients that are likely to relapse. The acquired ER regulatory regions associated with poor clinical outcome observed in primary tumours reveal gene signatures that predict clinical outcome in ER-positive disease exclusively. We find that the differential ER-binding programme observed in tumours from patients with poor outcome is not due to the selection of a rare subpopulation of cells, but is due to the FOXA1-mediated reprogramming of ER binding on a rapid timescale. The parallel redistribution of ER and FOXA1 binding events in drug-resistant cellular contexts is supported by histological co-expression of ER and FOXA1 in metastatic samples. By establishing transcription-factor mapping in primary tumour material, we show that there is plasticity in ER-binding capacity, with distinct combinations of cis-regulatory elements linked with the different clinical outcomes.

Cooperative interaction between retinoic acid receptor-alpha and estrogen receptor in breast cancer.

Retinoic acid receptor-alpha (RAR alpha) is a known estrogen target gene in breast cancer cells. The consequence of RAR alpha induction by estrogen was previously unknown. We now show that RAR alpha is required for efficient estrogen receptor-alpha (ER)-mediated transcription and cell proliferation. RAR alpha can interact with ER-binding sites, but this occurs in an ER-dependent manner, providing a novel role for RAR alpha that is independent of its classic role. We show, on a genome-wide scale, that RAR alpha and ER can co-occupy regulatory regions together within the chromatin. This transcriptionally active co-occupancy and dependency occurs when exposed to the predominant breast cancer hormone, estrogen--an interaction that is promoted by the estrogen-ER induction of RAR alpha. These findings implicate RAR alpha as an essential component of the ER complex, potentially by maintaining ER-cofactor interactions, and suggest that different nuclear receptors can cooperate for effective transcriptional activity in breast cancer cells.

Transducin-like enhancer protein 1 mediates estrogen receptor binding and transcriptional activity in breast cancer cells.

Estrogen receptor (ER) binds to distal enhancers within the genome and requires additional factors, such as the Forkhead protein FoxA1, for mediating chromatin interactions. We now show that the human Groucho protein, Transducin-like enhancer protein 1 (TLE1), positively assists some ER-chromatin interactions, a role that is distinct from its general role as a transcriptional repressor. We show that specific silencing of TLE1 inhibits the ability of ER to bind to a subset of ER binding sites within the genome, a phenomenon that results in perturbations in phospho-RNA Pol II recruitment. Furthermore, TLE1 is essential for effective ER-mediated cell division. We have discovered a distinct role for TLE1, as a necessary transcriptional component of the ER complex, where it facilitates ER-chromatin interactions.

Regulation of ERBB2 by oestrogen receptor-PAX2 determines response to tamoxifen.

Crosstalk between the oestrogen receptor (ER) and ERBB2/HER-2 pathways has long been implicated in breast cancer aetiology and drug response, yet no direct connection at a transcriptional level has been shown. Here we show that oestrogen-ER and tamoxifen-ER complexes directly repress ERBB2 transcription by means of a cis-regulatory element within the ERBB2 gene in human cell lines. We implicate the paired box 2 gene product (PAX2), in a previously unrecognized role, as a crucial mediator of ER repression of ERBB2 by the anti-cancer drug tamoxifen. We show that PAX2 and the ER co-activator AIB-1/SRC-3 compete for binding and regulation of ERBB2 transcription, the outcome of which determines tamoxifen response in breast cancer cells. The repression of ERBB2 by ER-PAX2 links these two breast cancer subtypes and suggests that aggressive ERBB2-positive tumours can originate from ER-positive luminal tumours by circumventing this repressive mechanism. These data provide mechanistic insight into the molecular basis of endocrine resistance in breast cancer.

Enhancing infection preventionist certification success through a structured training program.

BACKGROUND: Certification in infection control (CIC) is a standardized indicator of the knowledge and competencies essential for effective infection prevention practice. Evidence measuring success of training programs for certfication in infection control is limited. METHODS: From 2017 through 2023, 51 novice infection preventionists (IPs) were enrolled in a training program that combined didactic learning, application of knowledge in practice, and mentorship from advanced-practice and near-peer IPs. Participants were tracked through completion of certification examination and pass rates were compared with rates for 2023 CIC candidates. RESULTS: All participants engaged in the training program attempted the CIC examination. The training group had a pass rate of 98%. This is 27% higher than the most recent rate published by Certification Board of Infection Control and Epidemiology (CBIC) of 71%. DISCUSSION: Participants were significantly more likely to pass the CIC exam on the first try, showing that a supported, competency-based training program can be successful in supporting novice IPs in certification success. CONCLUSIONS: Building foundational knowledge on key concepts in infection prevention and control and enhancing learning through supervised, direct application of skills improves CIC certification exam pass rates and supports progression of early career IPs to more independent practice.

Developing valid test bank of surveillance case study scenarios for inter-rater reliability.

Case studies are utilized for training on National Healthcare Safety Network (NHSN) healthcare associated infection surveillance definitions. Item discrimination and item analysis were applied to case studies to identify questions that most accurately assess infection preventionists (IPs) application of surveillance definitions.

Implementation of a pooled surveillance testing program for asymptomatic SARS-CoV-2 infections in K-12 schools and universities.

BACKGROUND: The negative impact of continued school closures during the height of the COVID-19 pandemic warrants the establishment of cost-effective strategies for surveillance and screening to safely reopen and monitor for potential in-school transmission. Here, we present a novel approach to increase the availability of repetitive and routine COVID-19 testing that may ultimately reduce the overall viral burden in the community. METHODS: We implemented a testing program using the SalivaClear࣪ pooled surveillance method that included students, faculty and staff from K-12 schools (student age range 5-18 years) and universities (student age range >18 years) across the country (Mirimus Clinical Labs, Brooklyn, NY). The data analysis was performed using descriptive statistics, kappa agreement, and outlier detection analysis. FINDINGS: From August 27, 2020 until January 13, 2021, 253,406 saliva specimens were self-collected from students, faculty and staff from 93 K-12 schools and 18 universities. Pool sizes of up to 24 samples were tested over a 20-week period. Pooled testing did not significantly alter the sensitivity of the molecular assay in terms of both qualitative (100% detection rate on both pooled and individual samples) and quantitative (comparable cycle threshold (Ct) values between pooled and individual samples) measures. The detection of SARS-CoV-2 in saliva was comparable to the nasopharyngeal swab. Pooling samples substantially reduced the costs associated with PCR testing and allowed schools to rapidly assess transmission and adjust prevention protocols as necessary. In one instance, in-school transmission of the virus was determined within the main office and led to review and revision of heating, ventilating and air-conditioning systems. INTERPRETATION: By establishing low-cost, weekly testing of students and faculty, pooled saliva analysis for the presence of SARS-CoV-2 enabled schools to determine whether transmission had occurred, make data-driven decisions, and adjust safety protocols. We provide strong evidence that pooled testing may be a fundamental component to the reopening of schools by minimizing the risk of in-school transmission among students and faculty. FUNDING: Skoll Foundation generously provided funding to Mobilizing Foundation and Mirimus for these studies.

Rabies in vaccinated dogs and cats in the United States, 1997-2001.

OBJECTIVE: To identify cases of rabies involving vaccinated dogs and cats in the United States. DESIGN: Retrospective data review. SAMPLE POPULATION: 41 states that reported >or= 1 rabid dog or cat between 1997 and 2001. PROCEDURES: States were contacted to request information on numbers of dogs and cats tested for rabies between 1997 and 2001. For animals with a history of rabies vaccination, respondents were asked to provide details of the vaccination history, age, history of exposure to rabid animals, time between exposure and onset of clinical signs, clinical signs, duration of clinical signs, and whether the animal had died or was euthanatized. RESULTS: 21 of the 41 (51%) states agreed to participate in the study. A total of 264 rabid dogs and 840 rabid cats were identified during the study period. Thirteen (4.9%) rabid dogs and 22 (2.6%) rabid cats had a history of rabies vaccination. Of these, 2 dogs and 3 cats were classified as currently vaccinated. Overall, 6 animals (1 dog and 5 cats) had a history of receiving 2 doses of rabies vaccine in their lifetime, including 2 cats that were classified as currently vaccinated. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that rabies is uncommon in vaccinated dogs and cats but can occur. Veterinarians should include rabies in the differential diagnosis for any dog or cat with clinical signs compatible with rabies regardless of vaccination history. Continued surveillance is imperative to document vaccination failure and identify trends related to vaccination failure.