Search Results (1,314)

Growth hormone (GH) signaling has been implicated in tumor progression and therapy resistance across multiple cancer types, yet its role in bladder cancer remains largely unexplored. In this study, we investigated the impact of GH and its receptor (GHR) on therapy resistance and disease progression in urothelial carcinoma (UC) through integrated transcriptomic and in vitro analyses. Transcriptomic profiling of The Cancer Genome Atlas bladder cancer cohort revealed that high tumoral GHR expression was associated with differential upregulation of genes involved in drug efflux, epithelial-to-mesenchymal transition (EMT), and extracellular matrix (ECM) remodeling. Notably, elevated GHR levels correlated with significantly reduced overall survival in patients with UC. In parallel, in vitro experiments demonstrated that GH promotes chemoresistance in UC cell lines via upregulation of ATP-binding cassette-containing (ABC) transporters and activation of EMT. GH also modulated ECM-remodeling-associated genes in a chemotherapy-dependent manner, including matrix metalloproteinases and tissue inhibitors of metalloproteinases. Importantly, these effects were abrogated by Pegvisomant, a GHR antagonist, indicating the functional relevance of GH/GHR signaling in the mediation of these phenotypes. Collectively, our findings support a mechanistic role for GH signaling in driving therapy resistance and tumor aggressiveness in bladder cancer and suggest GHR antagonism as a potential therapeutic strategy to improve treatment outcomes. Full article

Gingival inflammation compromises the integrity of the gingival epithelium and the underlying tissues, highlighting the need for adjuvant therapies with immunomodulatory and healing properties. Casearia sylvestris, a medicinal plant known as guaçatonga, is traditionally used to treat inflammatory lesions. This study aimed to investigate the effects of C. sylvestris on the synthesis of pro- and anti-inflammatory, proteolytic, and antioxidant molecules and on wound healing in epithelial cells. A human telomerase-immortalized gingival keratinocyte cell line (TIGKs) was used, and cells were exposed to Escherichia coli lipopolysaccharide (LPS) in the presence and absence of C. sylvestris extract, its diterpene-concentrated fraction, and its clerodane diterpene casearin J for 24 h and 48 h. Gene expression and protein synthesis were analyzed by RT-qPCR and ELISA, respectively. Nitric oxide (NO) and NF-κB activation were analyzed by Griess reaction and immunofluorescence, respectively. Additionally, cell viability was evaluated by alamarBlue^® assay, and an automated scratch assay was used for wound healing. LPS significantly increased the expression of cytokines (TNF-α, IL-1β, IL-6, IL-8, IL-10, IL-17), proteases (MMP-1 and MMP-13), iNOS as well as NO synthesis, and triggered NF-κB nuclear translocation. It also reduced IL-4 expression, cell viability, and cellular wound repopulation. Treatment with C. sylvestris derivatives significantly abrogated all aforementioned LPS-induced effects by 80–100%. Furthermore, even at higher concentrations, C. sylvestris did not affect cell viability, thus proving the safety of its derivatives. C. sylvestris exerts anti-inflammatory, antiproteolytic, and antioxidant effects on gingival keratinocytes, highlighting its potential as a valuable adjunct in the prevention and treatment of periodontal diseases. Full article

Dietary advanced glycation end-products (dAGEs) contained in high-sugar/fat and ultra-processed foods of the “Western diet” (WD) pattern predispose to several diseases by altering protein function or increasing oxidative stress and inflammation via RAGE (receptor for advanced glycation end-products). Although elevated endogenous AGEs are associated with loss of muscle mass and functionality (i.e., muscle wasting; MW), the impact of dAGEs on MW has not been elucidated. Here, we show that the most common dAGEs or their precursor, methylglyoxal (MGO), induce C2C12 myotube atrophy as endogenous AGE-derived BSA. ROS production, mitochondrial dysfunction, mitophagy, ubiquitin–proteasome activation, and inhibition of myogenic potential are common atrophying mechanisms used by MGO and AGE-BSA. Although of different origins, ROS are mainly responsible for AGE-induced myotube atrophy. However, while AGE-BSA activates the RAGE-myogenin axis, reduces anabolic mTOR, and causes mitochondrial damage, MGO induces glycolytic stress and STAT3 activation without affecting RAGE expression. Among thirty selected natural compounds, Vaccinium macrocarpon (VM), Camellia sinensis, and chlorophyll showed a surprising ability in counteracting in vitro AGE formation. However, only the standardized VM, containing anti-glycative metabolites as revealed by UHPLC-HRMS analysis, abrogates AGE-induced myotube atrophy. Collectively, our data suggest that WD-linked dAGE consumption predisposes to MW, which might be restricted by VM food supplements. Full article

Estrogens regulate many physiological processes in the human body, including the cardiovascular system. Importantly, Estradiol (E2) exerts its vascular protective actions, in part, by promoting endothelial repair via induction of endothelial cell (EC) proliferation, migration and angiogenesis. Recent evidence that microRNAs (miRNAs) play an important role in vascular health and disease as well as in regulating Estrogen actions in many cell types. We hypothesize that E2 may mediate its vascular protective actions via the regulation of miRNAs. Following initial screening, we found that E2 downregulates the levels of miR-193a-3p in ECs. Moreover, miR-193a-3p downregulation by miR-193a-3p-antimir mimicked the effects as E2 on EC growth, migration, and capillary formation. Restoring miR-193a-3p levels with mimics after E2 treatment abrogated the vasculogenic actions of E2, suggesting a key role of miR-193a-3p in E2-mediated EC-growth-promoting effects. We further investigated the cellular mechanisms involved and found that miR-193a-3p inhibits angiogenesis by blocking phosphoinositide-3-kinase (PI3K)/Akt-vascular endothelial growth factor (VEGF) and Activin receptor-like kinase 1 (ALK1)/SMAD1/5/8 signaling in ECs, both pathways that are important in E2-mediated vascular protection. Additionally, using reverse transcription polymerase chain reaction (RT-PCR), we demonstrate that E2 downregulates miR-193a-3p in ECs via Estrogen Receptor (ER)α, but not ERβ or G protein-coupled estrogen receptor (GPER). Moreover, these actions occur post-transcriptionally, as the expression of pri-miR-193a-3p was not affected. The anti-angiogenic actions of miR-193a-3p were also observed in in vivo Matrigel implant-based capillary formation studies in ovariectomized mice where E2 induced capillary formation, and these effects were abrogated in the presence of miR-193a-3p, but not in the control mimic. Assessment of miR-193a-3p levels in plasma collected from in vitro fertilization (IVF) subjects with low and high E2 levels showed significantly lower miR-193a-3p levels in responders during the high E2 period. Hence, our findings provide the first evidence that miR-193a-3p mimic inhibits angiogenesis whereas its antimir is angiogenic. Importantly, E2 mediates its regenerative actions on ECs/capillary formation by downregulating endogenous miR-193a-3p expression. Both miR-193a-3p mimic or antimir may represent important therapeutic molecules to prevent or to induce endothelial function in treating pathophysiologies associated with capillary growth. Full article

The abnormal growth of smooth muscle cells (SMCs) contributes to the vascular remodeling associated with coronary artery disease, a leading cause of death in women. Estradiol (E2) mediates cardiovascular protective actions, in part, by inhibiting the abnormal growth (proliferation and migration) of SMCs through various mechanism. Since microRNAs (miRNAs) play a major role in regulating cell growth and vascular remodeling, we hypothesize that miRNAs may mediate the protective actions of E2. Following preliminary leads from E2-regulated miRNAs, we found that platelet-derived growth factor (PDGF)-BB-induced miR-193a in SMCs is downregulated by E2 via estrogen receptor (ER)α, but not the ERβ or G-protein-coupled estrogen receptor (GPER). Importantly, miR-193a is actively involved in regulating SMC functions. The ectopic expression of miR-193a induced vascular SMC proliferation and migration, while its suppression with antimir abrogated PDGF-BB-induced growth, effects that were similar to E2. Importantly, the restoration of miR-193a abrogated the anti-mitogenic actions of E2 on PDGF-BB-induced growth, suggesting a key role of miR-193a in mediating the growth inhibitory actions of E2 in vascular SMCs. E2-abrogated PDGF-BB, but not miR-193a, induced SMC growth, suggesting that E2 blocks the PDGF-BB-induced miR-193a formation to mediate its anti-mitogenic actions. Interestingly, the PDGF-BB-induced miR-193a formation in SMCs was also abrogated by 2-methoxyestradiol (2ME), an endogenous E2 metabolite that inhibits SMC growth via an ER-independent mechanism. Furthermore, we found that miR-193a induces SMC growth by activating the phosphatidylinositol 3-kinases (PI3K)/Akt signaling pathway and promoting the G1 to S phase progression of the cell cycle, by inducing Cyclin D1, Cyclin Dependent Kinase 4 (CDK4), Cyclin E, and proliferating-cell-nuclear-antigen (PCNA) expression and Retinoblastoma-protein (RB) phosphorylation. Importantly, in mice, treatment with miR-193a antimir, but not its control, prevented cuff-induced vascular remodeling and significantly reducing the vessel-wall-to-lumen ratio in animal models. Taken together, our findings provide the first evidence that miR-193a promotes SMC proliferation and migration and may play a key role in PDGF-BB-induced vascular remodeling/occlusion. Importantly, E2 prevents PDGF-BB-induced SMC growth by downregulating miR-193a formation in SMCs. Since, miR-193a antimir prevents SMC growth as well as cuff-induced vascular remodeling, it may represent a promising therapeutic molecule against cardiovascular disease. Full article

Brain muscle ARNT-like1 (Bmal1) is a transcriptional factor, consisting of basic helix–loop–helix (bHLH) and PER-ARNT-SIM (PAS) domains, that plays a central role in circadian clock activity. However, the precise roles of the BMAL1-PAS domain, a circadian rhythm-regulating structure, remain unexplored in monocytes. Here, we highlight the BMAL1-PAS domain as a key structure in monocyte pleiotropic functions by using human monocytic cell line THP-1. THP-1 cells lacking the BMAL1-PAS-B domain (THP-1#207) abrogated the circadian expression of core clock genes. THP-1#207 cells exhibited less proliferation, glycolysis and oxidative phosphorylation activity, and LPS-induced IL-1β production, but exhibited more production of LPS-induced IL-10 than THP-1 cells. A quantitative proteomics analysis revealed significant expression changes in ~10% metabolic enzymes in THP-1#207 cells compared to THP-1 cells, including reduction in a rate-limiting enzyme hexokinase2 (HK2) in the glycolytic pathway. Importantly, treatment of THP-1 with 2-deoxy-D-glucose (2-DG), an HK2 inhibitor, largely recapitulated the phenotypes of THP-1#207 cells. These findings suggest that the BMAL1-PAS-B domain is an important structure for the regulation of proliferation, cellular energetics, and inflammatory response in THP-1 cells, at least in part, via the control of glycolytic activity. Thus, the BMAL1-PAS-B domain may become a promising pharmacological target to control inflammation. Full article

Immunotherapy targeting the immune functions of the tumor microenvironment (TME) is beneficial for colorectal cancer; however, the response rate is poor. Ciprofloxacin is a fluoroquinolone-class antibiotic that is used to treat bacterial infections. The purpose of this study is to assess the mechanism of ciprofloxacin that enhances anti-PD1 in colorectal cancer. We found that ciprofloxacin induced cytosolic DNA, including single-stranded and double-stranded DNA, formation in mouse CT26 colorectal adenocarcinoma cells. Molecules in DNA-sensing signaling such as cGAS, STING, and IFNβ mRNA and protein expression were elicited after ciprofloxacin treatment in CT26 cells. STING siRNA abrogated the cGAS-STING pathway activation by ciprofloxacin. In vivo, ciprofloxacin exhibited a synergistic effect with anti-PD1 to suppress tumor growth in a CT26 syngeneic animal model without biological toxicity. The examination of TME revealed that ciprofloxacin, alone and in combination therapy, induced M1 and red pulp macrophage production in the spleen. In tumors, M1 and M2 macrophage levels were increased by ciprofloxacin, and CD8⁺ T cell granzyme B expression was increased after combination therapy. STING showed the highest expression in tumor specimens after combination treatment. Ciprofloxacin may enhance the anti-PD1 efficacy and modulate the TME through the cGAS-STING pathway. Full article

Poloxamer (P) 188 attenuates myocardial ischemia/reperfusion injury through cell membrane stabilization. Cell–cell interactions between endothelial cells (ECs) and cardiomyocytes (CMs) further protect CMs: co-cultures showed that, at an optimal density, ECs protected CMs against hypoxia/reoxygenation (HR) injury. The mechanism of interaction with P188 still requires exploration. We examined if N(ω)-nitro-L-arginine methyl ester (LNAME), a non-specific nitric oxide (NO) synthase inhibitor, abolishes protection in the presence or absence of P188 and/or ECs. We co-cultured mouse coronary artery ECs in an insert atop mouse CMs plated at confluency on the bottom of a well. Normoxic controls remained in complete media while HR groups were exposed to 24 h hypoxia at 0.01% O₂ in serum- and glucose-free media, followed by 2 h reoxygenation in complete media. P188 (300 μM), LNAME (40 mM), or vehicle were administered upon reoxygenation. ECs at the used lower density did not decrease HR-triggered lactate dehydrogenase release or calcium overload in CMs by themselves. P188 reduced both indicators after HR by 16/18% without and by 22/25% with ECs, respectively. LNAME abrogated CM protection by P188. Neither intervention had an effect under normoxia. Our co-culture data indicates that P188 requires NO, not necessarily of endothelial origin, to elicit CM protection. Full article

Background. Metabolic dysfunction-associated steatotic liver disease (MASLD) affects more than 30% of the world population. Progression to its inflammatory state, MASH, is associated with increasing liver fibrosis, leading to end-stage liver disease (ESLD) and hepatocellular carcinoma (HCC). SW033291, an inhibitor of 15-PGDH (the PGE2 degradation enzyme), has been shown to increase in vivo regeneration of liver parenchyma, ameliorating oxidative stress and inflammation. We hypothesized that SW033291 abrogates MASH progression by inducing a paucity of the initial apoptotic switch and restoring physiological collagen’s microenvironment. Methods. The expression levels of the cell metabolic proteins FOXO1, mTOR, and SIRT7 were determined in a diet-induced MASH-mouse model at 16, 20, and 24 weeks. Non-targeted metabolomics in mouse plasma were measured by LC-MS/MS. Liver morphology and apoptotic activity were quantified by the NAS score and TUNEL assay, respectively. Statistical analyses between groups (NMC, HFD, and SW033291) were determined by ANOVA, t-test/Tukey’s post hoc test using GraphPad Prism. Metabolomics data were analyzed using R-lab. Results. The treated group showed significant decreases in total body fat, cellular oxidative stress, and inflammation and an increase in total lean mass with improved insulin resistance and favorable modulation of metabolic protein expressions (p < 0.05). SW033291 significantly decreased GS:SG, citric acid, and corticosterone, NAS scores (9.4 ± 0.2 vs. 6.2 ± 0.1, p < 0.05), liver fibrosis scores (1.3 ± 0.5 vs. 0.25 ± 0.1, p < 0.05), and apoptotic activity (43.9 ± 4.6 vs. 0.38 ± 0.1%, p < 0.05) compared with controls at 24W. Conclusions. The inhibition of 15-PGDH appears to normalize the metabolic and morphological disturbances during MASH progression with a paucity of the initial apoptotic switch, restoring normal collagen architecture. SW033291 warrants further investigation for its translation. Full article

Acetaminophen, or paracetamol (PCM), is a common painkiller used to treat aches, pain, and fever. Nevertheless, PCM has been reported to be hepatotoxic and nephrotoxic in humans. Thus, there is a need to identify how this side effect can be treated. Previous studies have shown that Leea species possess antioxidative, anthelmintic, anti-cytotoxic, hepatoprotective, and nephroprotective properties. However, the role of Leea guineensis (LG) in modulating PCM-induced hepatotoxicity or nephrotoxicity remains unknown. Herein, we investigate the possibility of Leea guineensis leaf extract (LGE) to ameliorate PCM toxic effects, evaluate hepatic and renal function, oxidative stress markers, and safety, and perform molecular docking to predict affinities of Leea guineensis extract compounds for their targets compared to PCM. An in vivo rat model was used for Leea guineensis extract or silymarin (SLM, standard drug) at various concentrations, and it was co-administered with PCM. We observed that Leea guineensis extract is rich in phytochemical constituents, and its treatment in rats did not significantly affect body weight. Our data showed that PCM increased bilirubin, creatinine, uric acid, Alanine aminotransferase (ALT), and cholesterol levels but decreased Aspartate aminotransferase (AST) in plasma. Moreover, it increased lipid peroxidation (MDA) levels in the liver and kidneys, while the total protein was elevated in the latter. Interestingly, Leea guineensis extract and SLM abrogated the elevated parameters due to PCM toxicity. Importantly, histopathological examination showed that Leea guineensis extract demonstrated the potential to ameliorate hepatic and renal lesions caused by PCM intoxication, thus demonstrating its safety. Furthermore, comparative molecular binding affinities of the study ligands binding the target corroborate the experimental findings. Our study shows that L. guineensis leaf extract, through its rich phytochemicals, can protect the liver and kidneys against the toxic effects of paracetamol in a dose-dependent manner. Full article

Background: Organic anion transporter 3 (OAT3) in the kidney proximal tubule cells plays a critical role in renal clearance of numerous endogenous metabolites and exogenous drugs and toxins. In this study, we discovered that epidermal growth factor (EGF) regulates the expression and activity of OAT3 through palmitoylation, a novel mechanism that has never been described in the OAT field. Methods/Results: Our results showed that treatment of OAT3-expressing cells with EGF led to a ~40% increase in OAT3 expression and OAT3-mediated transport of estrone sulfate, a prototypical substrate for OAT3. EGF-stimulated OAT3 transport activity was abrogated by H-89, a protein kinase A (PKA) inhibitor, indicating that an EGF-PKA signaling pathway is involved in the regulation of OAT3. We also showed that treatment of OAT3-expressing cells with EGF resulted in an enhancement of OAT3 palmitoylation, a novel type of post-translational modification for OATs, and such an enhancement was blocked by H-89, suggesting that the EGF-PKA signaling pathway participated in the modulation of OAT3 palmitoylation. Palmitoylation was catalyzed by a group of palmitoyltransfereases, and we showed that OAT3 palmitoylation and expression were inhibited by 2-BP, a general inhibitor for palmitoyltransfereases. We also explored the relationship among EGF/PKA signaling, OAT palmitoylation, and OAT transport activity. We treated OAT3-expressing cells with EGF or Bt2-cAMP, a PKA activator, in the presence and absence of 2-BP, followed by the measurement of OAT3-mediated transport of estrone sulfate. We showed that both EGF- and Bt2-cAMP-stimulated OAT3 transport activity were abolished by 2-BP, suggesting that palmitoylation mediates the regulation of EGF/PKA on OAT3. Finally, we showed that osimertinib, an anti-cancer drug/EGFR inhibitor, blocked EGF-stimulated OAT3 transport activity. Conclusions: In summary, we provided the first evidence that palmitoylation transduces the EGF/PKA signaling pathway to the modulation of OAT3 expression and function. Our study also provided an important implication that during comorbidity therapies, EGFR inhibitor drugs could potentially decrease the transport activity of renal OAT3, which would subsequently alter the therapeutic efficacy and toxicity of many co-medications that are OAT3 substrates. Full article

Background: Sepsis-induced acute lung injury (ALI) is a serious disease constituting a heavy burden on society due to high mortality and morbidity. Inflammation and oxidative stress constitute key pathological mechanisms in ALI caused by sepsis. LL-37 can improve the survival of septic mice. Nevertheless, its function and underlying mechanism in sepsis-evoked ALI is elusive. Methods: The human A549 alveolar epithelial cell line was treated with LL-37 or ZBP1 recombinant vector under LPS exposure. Then, the effects on cell oxidative stress injury, inflammatory response, and autophagy were analyzed. RNA-seq analysis was performed to detect the differentially expressed genes (DEGs) between the LPS and LPS/LL-37 groups. Furthermore, the effects of LL-37 on cecal ligation and the puncture (CLP)-constructed ALI model were explored. Results: LL-37 attenuated LPS-evoked oxidative injury in human alveolar epithelial cells by increasing cell viability and suppressing ROS, malondialdehyde, and lactate dehydrogenase levels and apoptosis. Moreover, LPS-induced releases of pro-inflammatory IL-18, TNF-α, and IL-1β were suppressed by LL-37. Furthermore, LPS’s impairment of autophagy was reversed by LL-37. RNA-seq analysis substantiated 1350 differentially expressed genes between the LPS and LPS/LL-37 groups. Among them was ZBP1, a significantly down-regulated gene with the largest fold change. Moreover, LL-37 suppressed LPS-increased ZBP1 expression. Importantly, ZBP1 elevation restrained LL-37-induced autophagy in LPS-treated cells and abrogated LL-37-mediated protection against LPS-evoked oxidative injury and inflammation. LL-37 ameliorated abnormal histopathological changes, tissue edema, the lung injury score, oxygenation index (PaO2/FiO2), and glycemia contents in the CLP-constructed ALI model, which were offset through ZBP1 elevation via its activator CBL0137. Additionally, LL-37 suppressed inflammation and oxidative stress in lung tissues, concomitant with autophagy elevation and ZBP1 down-regulation. Conclusions: LL-37 may alleviate the progression of sepsis-evoked ALI by attenuating pulmonary epithelial cell oxidative injury and inflammatory response via ZBP1-mediated autophagy activation, indicating a promising approach for the therapy of ALI patients. Full article

An experimental model of acute pulmonary damage was developed based on the intravenous injection of the phospholipase A₂ (PLA₂)-rich venom of Pseudechis papuanus (Papuan black snake) in mice. Venom caused pulmonary edema, with the accumulation of a protein-rich exudate, as observed histologically and by analysis of bronchoalveolar lavage fluid (BALF). In parallel, venom induced an increase in all of the pulmonary mechanical parameters evaluated, without causing major effects in terms of tracheal and bronchial reactivity. These effects were abrogated by incubating the venom with the PLA₂ inhibitor varespladib, indicating that this hydrolytic enzyme is responsible for these alterations. The venom was cytotoxic to endothelial cells in culture, hydrolyzed phospholipids of a pulmonary surfactant, and reduced the activity of angiotensin-converting enzyme in the lungs. The pretreatment of mice with the nitric oxide synthase inhibitor L-NAME reduced the protein concentration in the BALF, whereas no effect was observed when mice were pretreated with inhibitors of cyclooxygenase (COX), tumor necrosis factor-α (TNF-α), bradykinin, or neutrophils. Based on these findings, it is proposed that the rapid pathological effect of this venom in the lungs is mediated by (a) the direct cytotoxicity of venom PLA₂ on cells of the capillary–alveolar barrier, (b) the degradation of surfactant factor by PLA₂, (c) the deleterious action of nitric oxide in pulmonary tissue, and (d) the cytotoxic action of free hemoglobin that accumulates in the lungs as a consequence of venom-induced intravascular hemolysis. Our findings offer clues on the mechanisms of pathophysiological alterations induced by PLA₂s in a variety of pulmonary diseases, including acute respiratory distress syndrome (ARDS). Full article

The COVID-19 infection, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has evoked a worldwide pandemic. Even though vaccines have been developed on an enormous scale, but due to regular mutations in the viral gene and the emergence of new strains could pose a more significant problem for the population. Therefore, new treatments are always necessary to combat future pandemics. Utilizing an antiviral peptide as a model biomolecule, we trained a generative deep learning algorithm on a database of known antiviral peptides to design novel peptide sequences with antiviral activity. Using artificial intelligence (AI), specifically variational autoencoders (VAE) and Wasserstein autoencoders (WAE), we were able to generate a latent space plot that can be surveyed for peptides with known properties and interpolated across a predictive vector between two defined points to identify novel peptides that exhibit dose-responsive antiviral activity. Two hundred peptide sequences were generated from the trained latent space and the top peptides were subjected to a molecular docking study. The docking analysis revealed that the top four peptides (MSK-1, MSK-2, MSK-3, and MSK-4) exhibited the strongest binding affinity, with docking scores of −106.4, −126.2, −125.7, and −127.8, respectively. Molecular dynamics simulations lasting 500 ns were performed to assess their stability and binding interactions. Further analyses, including MMGBSA, RMSD, RMSF, and hydrogen bond analysis, confirmed the stability and strong binding interactions of the peptide–protein complexes, suggesting that MSK-4 is a promising therapeutic agent for further development. We believe that the peptides generated through AI and MD simulations in the current study could be potential inhibitors in natural systems that can be utilized in designing therapeutic strategies against SARS-CoV-2. Full article

The papers introduced in the Commentary present new insights and review aspects of current knowledge concerning the competition between viruses and their hosts for the cellular translation apparatus. Viruses depend on this apparatus and utilize diverse mechanisms to usurp it for the translation of viral mRNAs and to suppress synthesis of cellular proteins. Virus-induced modification of translation factors, selective abrogation of mRNA binding to ribosomes and degradation of cellular mRNAs all impair elements of the innate immune response, thereby undermining host defenses against infection. Various cellular mechanisms prevent translation of viral mRNAs, by modifying components of the translation apparatus to effect a generalized shut-off of translation or by binding of host proteins to viral mRNAs to induce their degradation or to prevent their engagement with the translation apparatus. Viruses have in turn evolved countermeasures to evade these defenses, for example by encoding proteins that impair the activity of host factors or via alterations in the sequence and structure of viral mRNAs. Such changes enable viral mRNAs to avoid recognition by host factors or to support translation initiation by specialized mechanisms that involve only a subset of the factors that are required by cellular mRNAs. Full article