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UBA1 is the primary E1 ubiquitin-activating enzyme responsible for generation of activated ubiquitin required for ubiquitination, a process that regulates stability and function of numerous proteins. Decreased or insufficient ubiquitination can cause or drive aging and many diseases. Therefore, a small-molecule enhancing UBA1 activity could have broad therapeutic potential. Here we report that auranofin, a drug approved for the treatment of rheumatoid arthritis, is a potent UBA1 activity enhancer. Auranofin binds to the UBA1’s ubiquitin fold domain and conjugates to Cys1039 residue. The binding enhances UBA1 interactions with at least 20 different E2 ubiquitin-conjugating enzymes, facilitating ubiquitin charging to E2 and increasing the activities of seven representative E3s in vitro. Auranofin promotes ubiquitination and degradation of misfolded ER proteins during ER-associated degradation in cells at low nanomolar concentrations. It also facilitates outer mitochondrial membrane-associated degradation. These findings suggest that auranofin can serve as a much-needed tool for UBA1 research and therapeutic exploration. Decreased activity of the E1 ubiquitin-activating enzyme UBA1 can contribute to aging and diseases like Alzheimer’s and VEXAS syndrome. Here, the authors found that auranofin, a rheumatoid arthritis drug, can significantly boost UBA1 activity.

Cadmium (Cd), one of the most toxic environmental and industrial pollutants, is known to exert gonadotoxic and spermiotoxic effects. In the present study, we examined the toxic effect of Cd on the testis of freshwater crab, Sinopotamon henanense. Crabs were exposed to different Cd concentrations (from 0 to 116.00 mg·L(-1)) for 7 d. Oxidative stress and apoptotic changes in the testes were detected. The activities of SOD, GPx and CAT initially increased and subsequently decreased with increasing Cd concentrations, which was accompanied with the increase in malondialdehyde (MDA) and H(2)O(2) content in a concentration-dependent manner. Typical morphological characteristic and physiological changes of apoptosis were observed using a variety of methods (HE staining, AO/EB double fluorescent staining, Transmission Electron Microscope observation and DNA fragmentation analysis), and the activities of caspase-3 and caspase-9 were increased in a concentration-dependent manner after Cd exposure. These results led to the conclusion that Cd could induced oxidative damage as well as apoptosis in the testis, and the apoptotic processes may be mediated via mitochondria-dependent apoptosis pathway by regulating the activities of caspase-3 and caspase-9.

Viral genome sequencing provides valuable information for antiviral development, yet its integration with machine learning for virtual screening remains underexplored. To bridge this gap, viral genome sequences were combined with structural data of approved and investigational antivirals to identify virus-selective agents. In parallel, quantitative structure-activity relationship (QSAR) models were built to predict pan-antivirals. Robust models were generated with the area under the receiver operating characteristic curve (AUC-ROC) >0.72 for virus-selective and >0.79 for pan-antiviral predictions. These models were applied to virtually screen ~360 K compounds for anti-SARS-CoV-2 activity. The 346 compounds identified by the models were tested using two in vitro assays, yielding hit rates of 9.4% (24/256) in the pseudotyped particle (PP) entry assay and 37% (47/128) in the RNA-dependent RNA polymerase (RdRp) assay. The top compounds showed potencies around 1 µM. This study provides a framework for virtual screening of virus-selective and pan- antivirals against emerging pathogens. Leveraging viral genome sequencing for antiviral drug development remains underexplored in machine learning applications. Here, the authors integrate viral genome sequences with drug structural data to create robust predictive models, identifying potential antivirals (e.g., anti-SARS-CoV-2 compounds).

Emerging evidence has shown that dioxin causes dysregulation of microRNAs (miRs) in a variety of tissues or cells. However, little is known about dioxin effects on neuronal miRs expression. In the present study, 277 differentially expressed miRs were identified by miRs microarray analysis in 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD, at 10 −10  M) treated SK-N-SH neuroblastoma cells. Among them, 53 miRs exhibited changes of more than 0.4-fold. Consistent with the microarray data, we verified the induction effect of TCDD on hsa-miR-608 expression, which is a primate-specific miR associated with brain functions. Bioinformatics analysis showed involvement of hsa-miR-608 in cytoskeleton organization, in which one of the hsa-miR-608 target genes, Cell Division Cycle 42 (CDC42), might play a role. We also confirmed induction of CDC42 expression by TCDD in SK-N-SH cells. TCDD induced the expression of CDC42 mRNA in hsa-miR-608 inhibitor transfected cells more obviously than in control cells, suggesting involvement of both transcriptional and post-transcriptional mechanisms in the TCDD-induced CDC42 regulation. Furthermore, CH223191, an antagonist of the aryl hydrocarbon receptor (AhR), counteracted TCDD-induced hsa-miR-608 and CDC42 expression. These results indicated that AhR not only mediates transcriptional induction of CDC42, but also hsa-miR-608-induced post-transcriptional regulation of CDC42 in dioxin treated neuroblastoma cells.

Cell–substrate interaction is important in tissue engineering. Vascular smooth muscle cells (VSMCs) cultured on the microgrooved surface of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx) showed a distinctive polarized morphology and a high expression level of let-7a compared with the flat substrates. LIMK2, a crucial regulator of actin dynamics, was identified as a new target of let-7a. F-Actin content on flat substrates was significantly higher than that on microgrooved ones. Either overexpression of let-7a on flat substrates or inhibited expression on microgrooved substrates can rescue the difference. In accord with actin dynamics, the expressions of contractile smooth muscle markers, such as SM22 and SMA, decreased in VSMCs cultured on microgrooved substrates compared to those on flat ones, though PHBHHx can induce the synthetic-to-contractile phenotype shift. These results indicate that microgrooved PHBHHx could enhance actin dynamics of VSMCs through let-7a-involved regulation and trigger a synthetic shift.

The data in Table 1 in this article originate from the same experiment and overlap with the results in the last columns (day 7) in Figures 4, 1 ,2 and 3 from the authors' previous publication in Sichuan Journal of Zoology titled 'Effects of Cadmium on Spermatic Antioxidant Enzyme Activities and Lipid Peroxidation in Freshwater Crab Sinopotamon yangtsekiense'. The publication in PLOS ONE focuses on cadmium-induced oxidative stress and apoptotic changes in the testis of freshwater crab Sinopotamon henanense, while the article published in Sichuan Journal of Zoology reported the effects of cadmium on antioxidant enzyme activities and lipid peroxidation in the same species.

To correlate medium parameters and pressure oscillation in SRM (Solid Rocket Motor) combustion chamber, a two-dimensional axisymmetric model was developed based on the typical VKI (Von Karman Institute for Fluid Dynamics) motor. Medium temperature and working pressure as the key parameters, LES (Large Eddy Simulation) was carried out for two groups of different models. Finally, pressure evolution and its FFT (Fast Fourier Transform) results were obtained. It indicates that for SRM with the same structure, medium temperature determines the frequency of pressure oscillation, and working pressure dictates its amplitude.

Toxicology in the 21 Century (Tox21) assay data provide a valuable resource for the prediction of toxicity using machine learning models. However, the performances of these models previously developed using the pre-existing Tox21 assay data were less than ideal, likely due to insufficient coverage of the biological response space by the assay targets. This study aimed to assess whether expanding the Tox21 portfolio with new assays that probe under-represented targets/pathways related to unanticipated adverse drug effects could improve the predictive capacity of assay data for toxicity such as drug induced liver injury (DILI) and cardiotoxicity (DICT). Models were constructed using data from the pre-existing panel of 36 assay targets and the expanded panel of 49 assay targets. A feature selection approach was used to determine the optimal number of assays needed for each model. The models were then applied to predict the potential hepatotoxicity and cardiotoxicity of compounds in the Tox21 10K compound library. For both DILI and DICT prediction, the best-performing models developed using the expanded assay panel required a smaller number of assays to achieve the same level of performance compared to those based on the pre-existing assays. Models constructed by combining both assay data (pre-existing + expanded) and chemical structure consistently outperformed those constructed based on assay data alone, but showed similar performance to those constructed based on chemical structure. The compounds predicted to have the highest toxic potential were experimentally verified to demonstrate the effectiveness of our models in identifying new potentially toxic compounds. The expansion of the Tox21 assay panel has significantly enhanced the predictive capacity of assay data for predicting DILI and DICT potential. This improvement underscores the importance of a diverse and comprehensive assay portfolio in advancing safety assessment. https://doi.org/10.1289/EHP16190.

Endoplasmic reticulum-associated degradation (ERAD) is a critical protein quality control mechanism that also regulates lipid metabolism and calcium homeostasis. Dysregulation of ERAD and unfolded protein response underlies diseases including cancer, neurodegenerative disorders, and metabolic syndromes. Small molecule modulators of ERAD could enable mechanistic discovery and therapeutic intervention, but few have been identified. Using a high-content screening, we discovered several ERAD-modulating compounds, including NCATS-SM0225, an ERAD inhibitor that unexpectedly binds all three isoforms of VDAC, outer mitochondrial membrane proteins enriched at mitochondria-associated membranes. This led us to discover an essential role for VDACs in ERAD and ER-phagy. NCATS-SM0225 elevates cytosolic, ER, and mitochondrial calcium through calcium influx and IP3R–MCU activity. This calcium imbalance strengthens VDAC1–IP3R coupling and activates PERK, which phosphorylates STIM1 and drives degradation of key ERAD regulators. Loss of these components amplifies PERK signaling and selectively kills cancer cells while sparing normal cells. These findings uncover a cancer-specific role of VDACs in ERAD regulation and calcium signaling, highlighting a therapeutically actionable vulnerability. Here the authors present NCATS-SM0225, a small molecule that inhibits ERAD and selectively kills cancer cells by binding VDACs, disrupting calcium homeostasis, and triggering the PERK-STIM1 pathway to degrade ERAD regulators.

Although the chlorinated flame retardant Dechlorane (Dec) 602 has been detected in food, human blood, and breast milk, there is limited information on potential health effects, including possible immunotoxicity. We determined the immunotoxic potential of Dec 602 in mice by examining the expression of phenotypic markers on thymocyte and splenic lymphocyte subsets, Th1/Th2 transcription factors, and the production of cytokines and antibodies. Adult male C57BL/6 mice were orally exposed to environmentally relevant doses of Dec 602 (1 and 10 μg/kg body weight per day) for 7 consecutive days. Thymocyte and splenic CD4 and CD8 subsets and splenocyte apoptosis were examined by flow cytometric analysis. Cytokine expression was measured at both the mRNA and the protein levels. Levels of the transcription factors Th1 (T-bet and STAT1) and Th2 (GATA3) were determined using quantitative real-time polymerase chain reaction (qPCR). Serum levels of immunoglobulins IgG1, IgG2a, IgG2b and IgE were measured by enzyme-linked immunosorbent assay (ELISA). Splenic CD4+ and CD8+ T cell subsets were decreased compared with vehicle controls, and apoptosis was significantly increased in splenic CD4+ T cells. Expression (mRNA and protein) of Th2 cytokines [interleukin (IL)-4, IL-10, and IL-13] increased, and that of Th1 cytokines [IL-2, interferon (IFN)-γ and tumor necrosis factor (TNF)-α] decreased. The Th2 transcriptional factor GATA3 increased, whereas the Th1 transcriptional factors T-bet and STAT1 decreased. As additional indicators of the Th2-Th1 imbalance, production of IgG1 was significantly increased, whereas IgG2a was reduced. To our knowledge, we are the first to report evidence of the effects of Dec 602 on immune function in mice, with findings indicating that Dec 602 exposure favored Th2 responses and reduced Th1 function. Feng Y, Tian J, Xie HQ, She J, Xu SL, Xu T, Tian W, Fu H, Li S, Tao W, Wang L, Chen Y, Zhang S, Zhang W, Guo TL, Zhao B. 2016. Effects of acute low-dose exposure to the chlorinated flame retardant dechlorane 602 and Th1 and Th2 immune responses in adult male mice. Environ Health Perspect 124:1406-1413; http://dx.doi.org/10.1289/ehp.1510314.