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Exposure to heat stress triggers a well‐defined acute response marked by HSF1‐dependent transcriptional upregulation of heat shock proteins. Cells allowed to recover acquire thermotolerance, but this adaptation is poorly understood. By quantitative proteomics, we discovered selective upregulation of HSP70‐family chaperone HSPA1 and its co‐factors, HSPH1 and DNAJB1, in MCF7 breast cancer cells acquiring thermotolerance. HSPA1 was found to have dual function during heat stress response: (i) During acute stress, it promotes the recruitment of the 26S proteasome to translating ribosomes, thus poising cells for rapid protein degradation and resumption of protein synthesis upon recovery; (ii) during thermotolerance, HSPA1 together with HSPH1 maintains ubiquitylated nascent/newly synthesized proteins in a soluble state required for their efficient proteasomal clearance. Consistently, deletion of HSPH1 impedes thermotolerance and esophageal tumor growth in mice, thus providing a potential explanation for the poor prognosis of digestive tract cancers with high HSPH1 and nominating HSPH1 as a cancer drug target. We propose dual roles of HSPA1 either alone or in complex with HSPH1 and DNAJB1 in promoting quality control of nascent/newly synthesized proteins and cellular thermotolerance. Synopsis: How cells exposed to heat stress acquire thermotolerance is poorly understood. Here, quantitative proteomics identifies upregulation of HSP70‐family chaperone HSPA1, which fulfills dual function in quality control of nascent proteins at translating ribosomes. Proteotoxic stress causes translation arrest, ubiquitylation of nascent/newly synthesized proteins, and proteasome recruitment to ribosomes.Proteasome recruitment to ribosomes is augmented by HSP70 activity independently of nascent chain ubiquitylation.HSPA1 in complex with HSPH1‐DNAJB1 cofactors maintains solubility and proteasomal clearance of ubiquitylated proteins.Low HSPH1 expression impedes nascent‐protein quality control and tumor growth, correlating with favorable outcome. [ABSTRACT FROM AUTHOR]

Flumioxazin is a widely applied herbicide for the control of broadleaf weeds, including aquatic plants. Current evidence suggests that flumioxazin could induce cardiac defects (ventricular septal defects) in vertebrates, but the underlining mechanisms remain unclear. Because of the inhibitory effect of flumioxazin on polyphenol oxidase, the assumption is made that flumioxazin‐induced cardiotoxicity is caused by oxidative stress. To verify whether oxidative stress plays an important role in flumioxazin‐induced cardiotoxicity, we compared the differences in heart phenotype, oxidative stress level, apoptosis, and gene expression between flumioxazin exposure and a normal environment, and we also tested whether cardiotoxicity could be rescued with astaxanthin. The results showed that flumioxazin induced both cardiac malformations and the abnormal gene expression associated with cardiac development. Cardiac malformations included pericardial edema, cardiac linearization, elongated heart, cardiomegaly, cardiac wall hypocellularity, myocardial cell atrophy with a granular appearance, and a significant gap between the myocardial intima and the adventitia. An increase in oxidative stress and apoptosis was observed in the cardiac region of zebrafish after exposure to flumioxazin. The antioxidant astaxanthin reversed the cardiac malformations, excessive production of reactive oxygen species (ROS), and expression of genes for cardiac developmental and apoptosis regulation induced by flumioxazin. In addition, flumioxazin also activated aryl hydrocarbon receptor (AhR) signaling pathway genes (aryl hydrocarbon receptor 2 [ahr2], cytochrome p450 family subfamily a [cyp1a1], and b [cyp1b1]) and increased the concentration of porphyrins. The results suggest that excessive ROS production, which could be mediated through AhR, led to apoptosis, contributing to the cardiotoxicity of flumioxazin in zebrafish embryos. Environ Toxicol Chem 2023;42:2737–2746. © 2023 SETAC [ABSTRACT FROM AUTHOR]

eIF3, whose subunits are frequently overexpressed in cancer, regulates mRNA translation from initiation to termination, but mRNA‐selective functions of individual subunits remain poorly defined. Using multiomic profiling upon acute depletion of eIF3 subunits, we observed that while eIF3a, b, e, and f markedly differed in their impact on eIF3 holo‐complex formation and translation, they were each required for cancer cell proliferation and tumor growth. Remarkably, eIF3k showed the opposite pattern with depletion promoting global translation, cell proliferation, tumor growth, and stress resistance through repressing the synthesis of ribosomal proteins, especially RPS15A. Whereas ectopic expression of RPS15A mimicked the anabolic effects of eIF3k depletion, disruption of eIF3 binding to the 5′‐UTR of RSP15A mRNA negated them. eIF3k and eIF3l are selectively downregulated in response to endoplasmic reticulum and oxidative stress. Supported by mathematical modeling, our data uncover eIF3k‐l as a mRNA‐specific module which, through controlling RPS15A translation, serves as a rheostat of ribosome content, possibly to secure spare translational capacity that can be mobilized during stress. Are there mRNA‐selective functions of individual eIF3 subunits? Here, multiomic profiling upon acute depletion of eIF3 subunits uncovers eIF3k‐l as an mRNA‐specific module that serves as a rheostat of ribosome content, securing spare translational capacity that can be mobilized during stress. Acute depletion of eIF3 subunits has subunit‐selective impact on holo‐eIF3 architecture.eIF3k depletion uniquely causes increased tumor growth and ribosome content.eIF3k depletion boosts the translation of RPS15A mRNA through an eIF3‐binding site in the 5′‐UTR.eIF3k and eIF3l are selectively downregulated by cellular stress, thus promoting cell survival. [ABSTRACT FROM AUTHOR]

Newcastle disease virus (NDV) is an intrinsically tumor-specific virus, many researchers have reported that lentogenic NDV is a safe and effective agent for human cancer therapy. It had been demonstrated that the amino acid sequence of the fusion protein cleavage site is a major factor in the pathogenicity and anti-tumor efficacy of rNDV. However, the role of Hemagglutinin-Neuraminidase (HN) gene that contributes to virulence and anti-tumor efficacy remains undefined. To assess the role of HN gene in virus pathogenicity and anti-tumor efficacy, a reverse genetic system was developed using the lentogenic NDV Clone30 strain to provide backbone for gene exchange. Chimeric virus (rClone30-Anh(HN)) created by exchange of the HN gene of lentogenic strain Clone30 with HN gene of mesogenic strain produce no significant changes in virus pathogenicity as assessed by conducting the mean death time (MDT) and intracerebral pathogenicity index (ICPI) assays. In vitro , infection with chimeras could induce the formation of syncytium relative significantly in HepG2 cells. Furthermore, chimeras was shown to induce the cell apoptosis via MTT and Annexin V-PI assays, reduce mitochondrial membrane potential and increase the mRNA transcription level of caspase 3. In vivo , ICR mice carrying tumor of hepatoma H22 cells were treated via intratumoral injection of chimeric virus. The treatment of chimera shows an obvious suppression in tumor volume. These results suggest that it could be an ideal approach to enhance the antitumor ability of Newcastle disease virus and highlighted the potential therapeutic application of rClone30-Anh(HN) as a viral vector to deliver foreign genes for treatment of cancers. [ABSTRACT FROM AUTHOR]

Butylparaben, a common endocrine disruptor in the environment, is known to be toxic to the reproductive system, heart, and intestines, but its nephrotoxicity has rarely been reported. In order to study the nephrotoxicity and mechanism of butylparaben, we examined the acute and chronic effects on human embryonic kidney cells (HEK293T) and zebrafish. Additionally, we assessed the potential remedial effects of salidroside against butylparaben-induced nephrotoxicity. Our in vitro findings demonstrated oxidative stress and cytotoxicity to HEK293T cells caused by butylparaben. In the zebrafish model, the concentration of butylparaben exposure ranged from 0.5 to 15 μM. An assortment of experimental techniques was employed, including the assessment of kidney tissue morphology using Hematoxylin-Eosin staining, kidney function analysis via fluorescent dextran injection, and gene expression studies related to kidney injury, development, and function. Additionally, butylparaben caused lipid peroxidation in the kidney, thereby damaging glomeruli and renal tubules, which resulted from the downregulation of the PI3K-AKT signaling pathway. Furthermore, salidroside ameliorated butylparaben-induced nephrotoxicity through the PI3K-AKT signaling pathway. This study reveals the seldom-reported kidney toxicity of butylparaben and the protective effect of salidroside against toxicological reactions related to nephrotoxicity. It offers valuable insights into the risks to kidney health posed by environmental toxins. [Display omitted] • Butylparaben causes oxidative stress and toxicity in HEK293T cells. • Butylparaben can induce acute kidney injury in zebrafish larvae. • Butylparaben can inflict chronic nephrotoxicity in adult zebrafish. • Salidroside mitigates butylparaben-induced nephrotoxicity, potentially via the PI3K-AKT signaling pathway. [ABSTRACT FROM AUTHOR]

• BAAPE induced developmental defects in zebrafish embryos at early stages. • Embryos exposure to BAAPE with a lethal concentration 50 (LC50) of 140 mg/L at 72 hours post fertilization (hpf). • BAAPE caused cardiotoxicity and changed the expression levels of key genes in cardiac development in zebrafish larvae. • BAAPE exposure induced production and accumulation of ROS and enhanced oxidative stress levels. • BAAPE caused mitochondria-mediated apoptosis in zebrafish larvae. Ethyl 3-(N-butylacetamido) propanoate (EBAAP) is one of the most widely used mosquito repellents worldwide, and is also commonly used to produce cosmetics. Residues have recently been detected in surface and groundwater in many countries, and their potential to harm the environment is unknown. Therefore, more studies are needed to fully assess the toxicity of EBAAP. This is the first investigation into the developmental toxicity and cardiotoxicity of EBAAP on zebrafish embryos. EBAAP was toxic to zebrafish, with a lethal concentration 50 (LC50) of 140 mg/L at 72 hours post fertilization (hpf). EBAAP exposure also reduced body length, slowed the yolk absorption rate, induced spinal curvature and pericardial edema, decreased heart rate, promoted linear lengthening of the heart, and diminished cardiac pumping ability. The expression of heart developmental-related genes (nkx2.5, myh6, tbx5a, vmhc, gata4, tbx2b) was dysregulated, intracellular oxidative stress increased significantly, the activities of catalase (CAT) and superoxide dismutase (SOD) decreased, and malondialdehyde (MDA) content increased significantly. The expression of apoptosis-related genes (bax/bcl2, p53, caspase9, caspase3) was significantly upregulated. In conclusion, EBAAP induced abnormal morphology and heart defects during the early stages of zebrafish embryo development by potentially inducing the generation and accumulation of reactive oxygen species (ROS) in vivo and activating the oxidative stress response. These events dysregulate the expression of several genes and activate endogenous apoptosis pathways, eventually leading to developmental disorders and heart defects. [ABSTRACT FROM AUTHOR]

Nephrotoxicity of oxyfluorfen to vertebrates remains unclear despite its wide use as a herbicide. In order to further study its nephrotoxicity and its underlying mechanism, we used human embryonic kidney cells and zebrafish to explore. HEK293T cells were exposed to 2, 4, 6 μg/mL oxyfluorfen for 24 h in vitro, and zebrafish were exposed to 0.4, 0.8, 1.2 mg/L oxyfluorfen for 72 h in vivo. We found that oxyfluorfen inhibits cell migration and induces oxidative stress and apoptosis, causing kidney damage or nephrotoxicity in embryonic and adult zebrafish. Oxyfluorfen triggered inflammation in zebrafish and causing severe periorbital and body edema in embryos. Oxyfluorfen induced the secretion of kidney injury markers, including urea nitrogen (BUN), creatinine (CR), and β-n-acetyl-glucosaminidase (NAG) in zebrafish. Additionally, oxyfluorfen affected the homeostasis of oxidant and antioxidant systems, leading to reactive oxygen species (ROS) overload. Oxyfluorfen also damaged the glomerular podocytes and induced apoptosis of proximal tubules, which is harmful to normal body function and the renal filtration system. These results indicate that oxyfluorfen is a potential environmental hazard that can cause severe kidney injury and affect the health of organisms. [Display omitted] • Ultraviolet light will aggravate the toxicity of oxyfluorfen. • Oxyfluorfen exposure can affect embryogenesis of Zebrafish. • Oxyfluorfen causes nephrotoxicity in embryonic and adult zebrafish. • Oxyfluorfen induces oxidative stress and inflammation in HEK293T cell and zebrafish. [ABSTRACT FROM AUTHOR]

Fibroblast growth factor 21 (FGF21) is a hormone secreted predominantly in the liver, pancreas and adipose tissue. Recently, it has been reported that FGF21-Transgenic mice can extend their lifespan compared with wild type counterparts. Thus, we hypothesize that FGF21 may play some roles in aging of organisms. In this study d -galactose ( d -gal)-induced aging mice were used to study the mechanism that FGF21 protects mice from aging. The three-month-old Kunming mice were subcutaneously injected with d -gal (180 mg·kg − 1 ·d − 1 ) for 8 weeks and administered simultaneously with FGF21 (1, 2 or 5 mg·kg − 1 ·d − 1 ). Our results showed that administration of FGF21 significantly improved behavioral performance of d -gal-treated mice in water maze task and step-down test, reduced brain cell damage in the hippocampus, and attenuated the d -gal-induced production of MDA, ROS and advanced glycation end products (AGEs). At the same time, FGF21 also markedly renewed the activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and total anti-oxidation capability (T-AOC), and decreased the enhanced total cholinesterase (TChE) activity in the brain of d -gal-treated mice. The expression of aldose reductase (AR), sorbitol dehydrogenase (SDH) and member-anchored receptor for AGEs (RAGE) declined significantly after FGF21 treatment. Furthermore, FGF21 suppressed inflamm-aging by inhibiting IκBα degradation and NF-κB p65 nuclear translocation. The expression levels of pro-inflammatory cytokines, such as TNF-α and IL-6, decreased significantly. In conclusion, these results suggest that FGF21 protects the aging mice brain from d -gal-induced injury by attenuating oxidative stress damage and decreasing AGE formation. [ABSTRACT FROM AUTHOR]

It has been demonstrated that circulating FGF21 levels are elevated in the serum and synovial fluid of patients with rheumatoid arthritis (RA). The aim of this study is to investigate efficacy of FGF21 for treatment of RA and the molecular mechanisms of the therapeutic effect on collagen-induced arthritis (CIA). Mice with CIA were subcutaneously administered with FGF21 (5, 2 or 1 mg·kg − 1 ·d − 1 ), IL-1β antibody (5 mg·kg − 1 ·d − 1 ), IL-17A antibody (5 mg·kg − 1 ·d − 1 ) and dexamethasone (DEX) (1 mg·kg − 1 ·d − 1 ), respectively. The effects of treatment were determined by arthritis severity score, histological damage and cytokine production. The activation of NF-κB was analyzed by Western blotting. We also detected the levels of oxidative stress parameters. Our results showed that FGF21 had beneficial effects on clinical symptom and histological lesion of CIA mice. Similar to antibody and DEX, FGF21 treatment alleviated the severity of arthritis by reducing humoral and cellular immune responses and down-regulating the expression of pro-inflammatory cytokines. FGF21 treatment also reduced the expression of TNF-α, IL-1β, IL-6, IFN-γ and MMP-3 and increased level of IL-10 in the spleen tissue or the plasma of CIA mice in a dose-dependent manner. Furthermore, FGF21 inhibited IκBα degradation and NF-κB p65 nuclear translocation and induced significant changes of oxidative stress parameters (MDA, SOD, CAT, GSH-PX and GSH) in the plasma. FGF21 exerts therapeutic efficacy for RA through antioxidant reaction and inhibiting NF-κB inflammatory pathway. This study provides evidence that FGF21 may be a promising therapeutic agent for RA patients. [ABSTRACT FROM AUTHOR]

SMIP004-7 is a small molecule inhibitor of mitochondrial respiration with selective in vivo anti-cancer activity through an as-yet unknown molecular target. We demonstrate here that SMIP004-7 targets drug-resistant cancer cells with stem-like features by inhibiting mitochondrial respiration complex I (NADH:ubiquinone oxidoreductase, complex I [CI]). Instead of affecting the quinone-binding site targeted by most CI inhibitors, SMIP004-7 and its cytochrome P450-dependent activated metabolite(s) have an uncompetitive mechanism of inhibition involving a distinct N-terminal region of catalytic subunit NDUFS2 that leads to rapid disassembly of CI. SMIP004-7 and an improved chemical analog selectively engage NDUFS2 in vivo to inhibit the growth of triple-negative breast cancer transplants, a response mediated at least in part by boosting CD4+ and CD8+ T cell-mediated immune surveillance. Thus, SMIP004-7 defines an emerging class of ubiquinone uncompetitive CI inhibitors for cell autonomous and microenvironmental metabolic targeting of mitochondrial respiration in cancer. [Display omitted] • SMIP004 compounds inhibit NADH:ubiquinone oxidoreductase (complex I) • Unique ubiquinone uncompetitive mechanism of inhibition • In vivo target engagement involves complex I subunit NDUFS2 • Complex I inhibition reverses hypoxia and promotes cancer immune surveillance Mitochondrial complex I is identified as the target of cancer selective cytotoxic agent SMIP004-7. Jain et al. show that anti-tumor activity involves ubiquinone uncompetitive inhibition of complex I, leading to a reversal of tumor hypoxia and promotion of tumor immune surveillance. [ABSTRACT FROM AUTHOR]

eIF3, a multi-subunit complex with numerous functions in canonical translation initiation, is known to interact with 40S and 60S ribosomal proteins and translation elongation factors, but a direct involvement in translation elongation has never been demonstrated. We found that eIF3 deficiency reduced early ribosomal elongation speed between codons 25 and 75 on a set of ∼2,700 mRNAs encoding proteins associated with mitochondrial and membrane functions, resulting in defective synthesis of their encoded proteins. To promote elongation, eIF3 interacts with 80S ribosomes translating the first ∼60 codons and serves to recruit protein quality-control factors, functions required for normal mitochondrial physiology. Accordingly, eIF3e+/− mice accumulate defective mitochondria in skeletal muscle and show a progressive decline in muscle strength. Hence, eIF3 interacts with 80S ribosomes to enhance, at the level of early elongation, the synthesis of proteins with membrane-associated functions, an activity that is critical for mitochondrial physiology and muscle health. • eIF3—via eIF3e—promotes mRNA selective early translation elongation • eIF3e-dependent mRNAs encode membrane, secretory, and organelle targeted proteins • eIF3 travels with 80S ribosomes until nascent chains emerge for subcellular targeting • In vivo , eIF3e promotes mitochondrial function and skeletal muscle health Lin et al. discovered that, in addition to its function in canonical translation initiation, multi-subunit eIF3 migrates with post-initiation 80S ribosomes to promote early translation elongation of mRNAs encoding organellar, secretory, and membrane-targeted proteins. Loss of eIF3's elongation and subcellular targeting activity leads to mitochondrial and skeletal muscle dysfunction. [ABSTRACT FROM AUTHOR]