Early Epigenetic Regulation of the Adaptive Immune Response Gene CIITA

The precise regulation of Major Histocompatibility class II (MHC-II) genes plays an important role in the control of the adaptive immune response. MHC-II genes are expressed constitutively in only a few cell types, but their expression can be induced by the inflammatory response cytokine interferon gamma (INF-γ). The regulation of MHC-II is controlled by a Master Regulator, the class II transactivator (CIITA). Multiple studies have shown that CIITA regulated expression of MHC-II is controlled and induced by INF-γ. It has been also shown that a functional CIITA gene is necessary for the expression of MHC-II genes. CIITA is thus a general regulator of both constitutive and inducible MHC-II expression. Although much is known about the transcription factors necessary for CIITA expression, there is little information as to the epigenetic modifications and the requisite enzymes needed to provide these transcription factors access to DNA. Previous studies in the Greer lab have shown that increased levels of acetylation of histones H3 upon INF-γ stimulation, as does tri-methylation of H3K4 upon prolonged cytokine stimulation. Similar observations were made at early time points post IFN-γ stimulation, where there is an instantaneous increase in the levels of H3K18ac and H3K4me3. In contrast to this, the levels of silencing modifications begin to drop with in the first 20 minutes of IFN-γ stimulation. The binding of STAT1 reaches its peak at about 60 minutes and the first transcripts for the protein start to appear as early as 40 minutes post the cytokines stimulation. Our study is the first to link the rapidly occurring epigenetic changes at the CIITA promoter pIV to EZH

Ectromelia virus encodes an anti-apoptotic protein that regulates cell death

AbstractApoptosis serves as a powerful defense against damaged or pathogen-infected cells. Since apoptosis is an effective defense against viral infection, many viruses including poxviruses, encode proteins to prevent or delay apoptosis. Here we show that ectromelia virus, the causative agent of mousepox encodes an anti-apoptotic protein EVM025. Here we demonstrate that expression of functional EVM025 is crucial to prevent apoptosis triggered by virus infection and staurosporine. We demonstrate that the expression of EVM025 prevents the conformational activation of the pro-apoptotic proteins Bak and Bax, allowing the maintenance of mitochondrial membrane integrity upon infection with ECTV. Additionally, EVM025 interacted with intracellular Bak. We were able to demonstrate that EVM025 ability to inhibit Bax activation is a function of its ability to inhibit the activity of an upstream BH3 only protein Bim. Collectively, our data indicates that EVM025 inhibits apoptosis by sequestering Bak and inhibiting the activity of Bak and Bax

Roles for common MLL/COMPASS subunits and the 19S proteasome in regulating CIITA pIV and MHC class II gene expression and promoter methylation

<p>Abstract</p> <p>Background</p> <p>Studies indicate that the 19S proteasome contributes to chromatin reorganization, independent of the role the proteasome plays in protein degradation. We have previously shown that components of the 19S proteasome are crucial for regulating inducible histone activation events in mammalian cells. The 19S ATPase Sug1 binds to histone-remodeling enzymes, and in the absence of Sug1, a subset of activating epigenetic modifications including histone H3 acetylation, H3 lysine 4 trimethylation and H3 arginine 17 dimethylation are inhibited at cytokine-inducible major histocompatibilty complex (MHC)-II and class II transactivator (CIITA) promoters, implicating Sug1 in events required to initiate mammalian transcription.</p> <p>Results</p> <p>Our previous studies indicate that H3 lysine 4 trimethylation at cytokine-inducible MHC-II and CIITA promoters is dependent on proteolytic-independent functions of 19S ATPases. In this report, we show that multiple common subunits of the mixed lineage leukemia (MLL)/complex of proteins associated with Set I (COMPASS) complexes bind to the inducible MHC-II and CIITA promoters; that overexpressing a single common MLL/COMPASS subunit significantly enhances promoter activity and MHC-II <it>HLA-DRA </it>expression; and that these common subunits are important for H3 lysine 4 trimethylation at MHC-II and CIITA promoters. In addition, we show that H3 lysine 27 trimethylation, which is inversely correlated with H3 lysine 4 trimethylation, is significantly elevated in the presence of diminished 19S ATPase Sug1.</p> <p>Conclusion</p> <p>Taken together, these experiments suggest that the 19S proteasome plays a crucial role in the initial reorganization of events enabling the relaxation of the repressive chromatin structure surrounding inducible promoters.</p

When Should Asymptomatic Persons Be Tested for COVID-19?

On August 24, 2020, the Centers for Disease Control and Prevention (CDC) updated its website to highlight that asymptomatic individuals, even those with exposure to a COVID-19 positive contact, do not necessarily need to be tested unless they have medical conditions associated with increased risk of severe illness from COVID-19. The CDC subsequently updated its guidance on September 19, 2020 to support testing of asymptomatic persons, including close contacts of persons with documented SARS-CoV-2 infection. In this editorial, the American Society for Microbiology Clinical and Public Health Microbiology Committee's Subcommittee on Laboratory Practices comments on testing of asymptomatic individuals relative to current medical knowledge of the virus and mitigation measures. Specific points are provided concerning such testing when undertaking contact tracing and routine surveillance. Limitations to consider when testing asymptomatic persons are covered, including the need to prioritize testing of contacts of positive COVID-19 cases. We urge the CDC to consult with primary stakeholders of COVID-19 testing when making such impactful changes in testing guidance

A deep learning based approach to segment exudates in retinal fundus images using Recurrent Residual U-Net

Diabetic Retinopathy (DR) is a severe medical concern, and early detection of DR can prevent blindness. Manually examining fundus images to detect lesions is time-consuming and requires expertise. Segmenting exudates from fundus images using Deep Learning methods provides an automated high precision solution to this problem. Our work proposes the Residual Recurrent U-Net (R2 U-Net) for segmenting exudates in retinal fundus images. The network consists of recurrent units with feedback connections leveraging local spatial information from neighboring pixels. There are multiple stacked recurrent units in each layer of the U-Net. Residual skip connections were introduced between different layers of the network to train deeper architectures. The model was trained on the publicly available IDRiD dataset and tested on IDRiD, E-Ophtha, and DiaretDB1 dataset. The metrics were computed at the pixel, exudate (or lesion), and image level. The model achieved a state-of-the-art 93.20% sensitivity and 99.80% specificity on the E-Ophtha at the exudate level, which is better than existing literature. An automated DR detection system would help not only people but also Ophthalmologists to treat Diabetic Retinopathy effectively.</p

Investigating The Impact Of Distance On Object Detection Accuracy in Unmanned Aerial Vehicle Systems Using MobileNetV3

This study investigates the feasibility of using Raspberry Pi-equipped Unmanned Aerial Vehicles (UAVs) for object detection. The research focuses on analyzing the impact of the distance between the UAV and the target person on the accuracy of object detection. Experimental results reveal a decrease in detection accuracy as the distance between the UAV and the target person increases, emphasizing the critical role of distance in efficient object detection systems. By combining drones, Raspberry Pi, and machine learning algorithms, this research showcases the potential of advanced object detection systems. The findings contribute to the growing application of UAV technology by refining and optimizing UAV-based object detection systems.</p

Trends in hospitalizations and epidemiological characteristics of adults Moyamoya disorder in the United States

There has been an increasing prevalence of Moyamoya disorder (MMD) reported from recent US literature. There is a paucity of data available regarding trends of prevalence and epidemiological factors in the United States. To goal of this study was to test the hypotheses that racial-, sex-specific MMD hospitalizations and epidemiological factors have been increasing in the United States over the last decade. In this retrospective observational study, using the National Inpatient Sample (NIS) database from 2005 to 2016, MMD-related hospitalizations in patients aged ≥18 years were identified. Trends of epidemiological factors were analyzed over time using the linear regression model with the significance of differences in trend over time assessed using the Wald test. Sex- and race-specific burden of MMD were calculated using the annual US Census data. Joinpoint regression model was used to evaluate trends of hospitalizations over time. A total of 24,484 adult hospitalizations were identified from January 2005 to September 2015 after excluding <18 years. Among them, approximately ~90% were aged ≤60 years, and 73.5% were females. The most common vascular and non-vascular presentations were ischemic stroke (17.3%) and seizures (21%), respectively. The trend of antithrombotic therapy has increased, while extracranial-intracranial bypass has remained stagnant. The actual average hospitalizations of MMD was 10.4 cases/ million population/year (range 4.1–17.9) and varied significantly by sex (females 14.7 [range 6.2–23.6] and males 5.9 [range 1.8–11.9]) over the 2005 to 2016 study period. The burden of hospitalizations also differed by race (African Americans 40.6 [range 32.8–63.7], Asians 24.8 [15.4–34.8], Non-Hispanic Whites 8.1 [range 6.4–11.5], and Hispanics 8.4 [2.8–12.8]) over the 2010 to 2016 study period. Joinpoint regression analysis showed an increasing overall MMD trend across the study period (+11.7%; P < 0.001), which was higher in males (+14.5% vs. +10.7%; P < 0.001). The Hispanic group had significantly increased hospitalizations over the years (+20.2%; P < 0.001). Although overall more prevalent in females, MMD-related hospitalizations are increasing more rapidly in males. Among the racial subpopulations, African Americans had the highest MMD-related hospitalizations, even higher than Asian Americans. MMD-related hospitalizations have increased quicker in Hispanics than in any other racial group. •Moyamoya disorder (MMD) is an increasingly recognized cause for stroke in the US. reka•African Americans have the highest MMD-related hospitalization rate among all racial groups.•Although overall higher in females, the rate of MMD-related hospitalizations are rising faster in males.•MMD presents more often as ischemic rather than hemorrhagic stroke in the Western population.•The use of antithrombotics has increased over the years; EC-IC bypass procedure performance rates have remained static

EVM005: An Ectromelia-Encoded Protein with Dual Roles in NF-κB Inhibition and Virulence

<div><p>Poxviruses contain large dsDNA genomes encoding numerous open reading frames that manipulate cellular signalling pathways and interfere with the host immune response. The NF-κB signalling cascade is an important mediator of innate immunity and inflammation, and is tightly regulated by ubiquitination at several key points. A critical step in NF-κB activation is the ubiquitination and degradation of the inhibitor of kappaB (IκBα), by the cellular SCF^β-TRCP ubiquitin ligase complex. We show here that upon stimulation with TNFα or IL-1β, <i>Orthopoxvirus</i>-infected cells displayed an accumulation of phosphorylated IκBα, indicating that NF-κB activation was inhibited during poxvirus infection. Ectromelia virus is the causative agent of lethal mousepox, a natural disease that is fatal in mice. Previously, we identified a family of four ectromelia virus genes (EVM002, EVM005, EVM154 and EVM165) that contain N-terminal ankyrin repeats and C-terminal F-box domains that interact with the cellular SCF ubiquitin ligase complex. Since degradation of IκBα is catalyzed by the SCF^β-TRCP ubiquitin ligase, we investigated the role of the ectromelia virus ankyrin/F-box protein, EVM005, in the regulation of NF-κB. Expression of Flag-EVM005 inhibited both TNFα- and IL-1β-stimulated IκBα degradation and p65 nuclear translocation. Inhibition of the NF-κB pathway by EVM005 was dependent on the F-box domain, and interaction with the SCF complex. Additionally, ectromelia virus devoid of EVM005 was shown to inhibit NF-κB activation, despite lacking the EVM005 open reading frame. Finally, ectromelia virus devoid of EVM005 was attenuated in both A/NCR and C57BL/6 mouse models, indicating that EVM005 is required for virulence and immune regulation <i>in vivo</i>.</p></div