Search Results (810)

The vast majority of viruses causing human and animal diseases are enveloped—their virions contain an outer lipid bilayer originating from a host cell. Small molecule antivirals targeting the lipid bilayer cover the broadest spectrum of viruses. In this context, we consider the chemical nature and mechanisms of action of membrane-targeting antivirals. They can affect virions by (1) physically modulating membrane properties to inhibit fusion of the viral envelope with the cell membrane, (2) physically affecting envelope lipids and proteins leading to membrane damage, pore formation and lysis, (3) causing photochemical damage of unsaturated membrane lipids resulting in integrity loss and fusion arrest. Other membrane-active compounds can target host cell membranes involved in virion’s maturation, coating, and egress (endoplasmic reticulum, Golgi apparatus, and outer membrane) affecting these last stages of viral reproduction. Both virion- and host-targeting membrane-active molecules are promising concepts for broad-spectrum antivirals. A panel of approved antivirals would be a superior weapon to respond to and control emerging disease outbreaks caused by new viral strains and variants. Full article

Background/Objectives: Ewing sarcoma (ES), a highly aggressive bone and soft tissue cancer occurring in children and young adults, is defined by the ETS fusion oncoprotein EWS::FLI1. Although event-free survival rates remain high in ES patients with localized disease, those with metastatic or relapsed disease face poor long-term survival odds. Topoisomerase 1 (TOP1) inhibitors are commonly used therapeutics in ES relapse regimens. Methods: In this work, we used a genome-wide CRISPR knockout library screen to identify the deletion of the TOP1 gene as a mechanism for resistance to topoisomerase 1 inhibitors. Using isogenic cell line models, we performed a high-throughput small-molecule screen to discover a small molecule, GNF-7, which had an IC50 that was 10-fold lower in TOP1-deficient cells when compared to the wild-type cells. Results: The characterization of GNF-7 demonstrated the molecule was highly active in the inhibition of CSK, p38α, EphA2, Lyn, and ZAK and specifically downregulated genes induced by the EWS::FLI1 fusion oncoprotein. Conclusions: Together, these results suggest that GNF-7 or small molecules with a similar kinase profile could be effective treatments for ES patients in combination with TOP1 inhibitors or for those patients who have developed resistance to TOP1 inhibitors. Full article

Adipose tissue macrophages (ATMs) play important roles in the progression of obesity-related severe acute pancreatitis (SAP). This study aimed to investigate the alterations of autophagic flux within ATMs, as well as the possible regulatory mechanisms. Obese mice were induced via high-fat diets. SAP was triggered using caerulein and lipopolysaccharide. Inflammatory injuries within pancreatic and adipose tissue were assessed. Autophagic flux, along with the expression of autophagosome-located soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins, were examined in ATMs. RNA-sequencing was performed to identify the possible regulatory factor, which was further validated. The results showed that obesity exacerbated inflammatory injuries. ATMs in obesity-related SAP exhibited impaired autophagic flux characterized by reduced autophagosome–lysosome fusion. Expression of autophagosome-located SNARE proteins decreased in ATMs. RNA-sequencing identified Forkhead box as the differentially expressed transcription factor associated with autophagy. The expression and transcriptional activity of Forkhead box O1 (FoxO1) decreased. The inhibition of FoxO1 exacerbated SNARE proteins’ suppression and autophagic flux impairment, while the activation of FoxO1 showed the opposite effect. In conclusion, obesity-induced impaired autophagic flux and autophagosome–lysosome fusion in ATMs are potentially regulated via autophagosome-located SNARE proteins and the transcription factor FoxO1. The impaired autophagic flux in ATMs aggravated inflammatory injuries of obesity-related SAP. Full article

The suppressive regulator of cell fusion, suppressyn, is specifically expressed in the human placenta and is thought to play a crucial role in trophoblast fusion or syncytialization. Previous studies have suggested that alterations in its expression are associated with aberrant placental development, such as the immature placental morphology observed in Down syndrome, and may contribute to the pathogenesis of fetal growth restriction. While syncytialization in trophoblasts is an essential process for normal placental development, the precise molecular causes of its dysregulation remain poorly understood. In the present study, we aimed to elucidate the potential contribution of genomic variation to the loss of suppressyn function, extending previous analyses of expression abnormalities in perinatal disorders. Through sequence analysis, (1) we identified six polymorphisms within the coding region of the suppressyn gene, and (2) discovered that certain deletions and specific amino acid substitutions result in a complete loss of suppressyn-mediated inhibition of cell fusion. Although these mutations have not yet been reported in disease-associated genomic databases, our findings suggest that comprehensive genomic studies of perinatal and other disorders may reveal pathogenic variants of suppressyn, thereby uncovering novel genetic contributions to placental dysfunction. It is also anticipated that these findings might direct the development of therapeutic strategies targeting loss-of-function mutations. Full article

Despite current vaccines and therapeutics targeting SARS-CoV-2, the causative agent of the COVID-19 pandemic, cases remain high causing a burden on health care systems. Spike-protein mediated membrane fusion of SARS-CoV-2 is a critical step in viral entry. Herein, we describe entry inhibitors identified by first screening a library of about 160 compounds and then analogue synthesis. Specifically, compound 261 was found to inhibit SARS-CoV-2 infection in a tissue model with IC₅₀ of 0.3 µM. Using NMR, we found that 261 interacts with key residues in the aromatic-rich region of the spike protein directly next to the transmembrane domain. Molecular dynamic simulations of the 261 binding pocket in the spike protein was also mapped to the transmembrane domain, consistent with NMR findings. The amino acids in the binding site are conserved among different coronaviruses known to infect humans; therefore, inhibitors targeting this conserved binding site could be a useful addition to current therapeutics and may have pan-coronavirus antiviral activities. Full article

The balance between cortical excitation and inhibition (E/I balance) in the cerebral cortex is critical for cognitive processing and neuroplasticity. Modulation of this balance has been linked to a wide range of neuropsychiatric and neurodegenerative disorders. The human visual system has well-differentiated magnocellular (M) and parvocellular (P) pathways, which provide a useful model to study cortical excitability using non-invasive visual flicker stimulation. We present an Arduino-driven non-image forming system to deliver controlled flickering light stimuli at different frequencies and wavelengths. By triggering the critical flicker fusion (CFF) frequency, we attempt to modulate the M-pathway activity and attenuate P-pathway responses, in parallel with induced optical scattering. EEG recordings were used to monitor cortical excitability and oscillatory dynamics during visual stimulation. Visual stimulation in the CFF, combined with induced optical scattering, selectively enhanced magnocellular activity and suppressed parvocellular input. EEG analysis showed a modulation of cortical oscillations, especially in the high frequency beta and gamma range. Our results support the hypothesis that visual flicker in the CFF, in addition to spatial degradation, initiates detectable neuroplasticity and regulates cortical excitation and inhibition. These findings suggest new avenues for therapeutic manipulation through visual pathways in diseases such as Alzheimer’s disease, epilepsy, severe depression, and schizophrenia. Full article

Background/Objectives: Lung cancer is a highly diverse disease, and reliable preclinical models that accurately reflect tumor characteristics are essential for studying lung cancer biology and testing new therapies. This study aimed to establish patient-derived tumor organoids (PDTOs) using small biopsy samples and surgical specimens to create a model system that preserves the genetic and histological features of the original tumors. Methods: PDTOs were generated from 163 lung cancer specimens, including 109 samples obtained using endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) or bronchoscopy, 52 surgical specimens, and 2 pleural fluid samples. The organoid establishment rate beyond passage three was assessed, and histological subtypes and genetic profiles were analyzed using immunohistochemical staining and targeted exome sequencing. Results: The overall PDTO establishment rate was 34.4% (56/163), and 44.6% (25/56) of these organoids retained the histological and genetic features of the parental tumors. Genetic analysis identified key mutations, including KRAS G12C, EGFR L858R, MET exon 14 skipping mutation, and ROS1 fusion. PDTOs successfully formed tumors in mice while maintaining the genetic characteristics of the original tumors. Co-culture of PDTOs with cancer-associated fibroblasts (CAFs) resulted in increased resistance to paclitaxel. In the co-culture model of PDTOs with immune cells, dose-dependent growth inhibition of PDTOs was observed in response to immune checkpoint inhibitors. Conclusions: PDTOs established from small biopsy and surgical specimens serve as a valuable model for studying lung cancer biology, tumor microenvironment interactions, and drug response. This model has the potential to improve personalized treatment strategies. Full article

Amyotrophic lateral sclerosis (ALS) is a progressive disease that degeneratively damages both upper and lower motor neurons, eventually resulting in muscular paralysis and death. Although ALS is broad in scope and commonly thought of as a motor neuron disease, more active research sheds light on the that role skeletal muscle plays in the development and progression of the disease. Muscle tissue in ALS patients and in animal models demonstrates severe regenerative deficits, including impaired myogenesis and impaired myoblast fusion. In ALS, muscle stem cells, known as satellite cells, show poor performance in activation, proliferation, and differentiation and thus contribute to ALS muscle wasting. Moreover, the pathological tissue environment that inhibits myoblast fusion is made up of proinflammatory cytokines, oxidative stress, and a lack of trophic signals from the neuromuscular junction, which greatly disrupts homeostatic regulation. It is likely that skeletal muscle is instead a dynamic player, fueling neuromuscular degeneration as opposed to a passive responder to denervation. One must appreciate the cellular and molecular changes that complicate muscle regeneration in ALS for effective treatment to be developed, permitting simultaneous interventions with both muscle and neurons. Full article

Respiratory syncytial virus (RSV) is a major human respiratory pathogen, particularly affecting infants, the elderly, and immunocompromised individuals. RSV exists in both spherical and filamentous forms, with the filamentous morphology associated with enhanced infectivity and cell-to-cell spread. Here, we demonstrate that RhoA, a small GTPase involved in cytoskeletal regulation, is essential for filamentous RSV morphogenesis through its role in organizing lipid raft microdomains. Rhosin, a selective RhoA inhibitor developed through structure-guided screening, disrupts GEF–RhoA interactions to block RhoA activation. The pharmacological inhibition of RhoA with Rhosin significantly reduced filamentous virion formation, disrupted RSV fusion (F) protein colocalization with lipid rafts, and diminished cell-to-cell fusion, without affecting overall viral replication. Scanning electron microscopy revealed that Rhosin-treated infected HEp-2 cells exhibited fewer and shorter filamentous projections compared to the extensive filament formation seen in untreated cells. β-galactosidase-based fusion assays confirmed that reduced filamentation corresponded with decreased cell-to-cell fusion. The biophysical separation of RSV spherical and filamentous particles by sucrose gradient velocity sedimentation, coupled with fluorescence and transmission electron microscopy, showed that Rhosin treatment shifted virion morphology toward spherical forms. This suggests that RhoA activity is critical for filamentous virion assembly, which may enhance viral spread. Immunofluorescence microscopy using lipid raft-selective dyes (DiIC₁₆) and fusion protein-specific antibodies revealed the strong co-localization of RSV proteins with lipid rafts. Importantly, the pharmacological inhibition of RhoA with Rhosin disrupted F protein partitioning into raft domains, underscoring the requirement for intact lipid rafts in assembly. These findings highlight a novel role for host RhoA signaling in regulating viral assembly through raft microdomain organization, offering a potential target for host-directed antiviral intervention aimed at altering RSV structural phenotypes and limiting pathogenesis. Full article

Mitochondria are dynamic in nature and depending on the energy demand they fuse and divide. This fusion-fission process is impaired in diabetic retinopathy and the promoter DNA of Mfn2, a fusion gene, is hypermethylated and its expression is downregulated. Long noncoding RNAs (RNAs with >200 nucleotides that do not encode proteins) can regulate gene expression by interacting with DNA, RNA, and proteins. Several LncRNAs are aberrantly expressed in diabetes, and among them, MALAT1 is upregulated in the retina, altering the expression of the genes associated with inflammation. Our aim was to investigate MALAT1’s role in mitochondrial dynamics in diabetic retinopathy. Using MALAT1-siRNA-transfected human retinal endothelial cells (HRECs) and human retinal Muller cells (RMCs) incubated in 20 mM D-glucose, Mfn2 expression and activity and its promoter DNA methylation were quantified. Mitochondrial integrity was evaluated by analyzing their fragmentation, ultrastructure, membrane potential, and oxygen consumption rate. Compared to normal glucose, high glucose upregulated MALAT1 expression and downregulated Mfn2 expression and activity in both HRECs and RMCs. MALAT1-siRNA ameliorated the glucose-induced increase in Mfn2 promoter DNA hypermethylation and its activity. MALAT1-siRNA also protected against mitochondrial fragmentation, structural damage, and reductions in the oxygen consumption rate. In conclusion, the upregulation of MALAT1 in diabetes facilitates Mfn2 promoter DNA hypermethylation in retinal vascular and nonvascular cells, leading to its suppression and the accumulation of the fragmented/damaged mitochondria. Thus, the regulation of MALAT1 has the potential to protect mitochondria and provide a possible new target to inhibit/prevent the blinding disease in diabetic patients. Full article

Background: Cancer vaccines represent a groundbreaking advancement in cancer immunotherapy, utilizing tumor antigens to induce tumor-specific immune responses. However, challenges like tumor-induced immune resistance and technical barriers limit the widespread application of predefined antigen vaccines. Here, we investigated the potential of viral protein R (Vpr) peptides as effective candidates for constructing anonymous antigen vaccines in situ by directly injecting at the tumor site and releasing whole-tumor antigens, inducing robust anti-tumor immune responses to overcome the limitations of predefined antigen vaccines. Methods: The cytotoxic effects of Vpr peptides were evaluated using the CCK8 reagent kit. Membrane penetration ability of Vpr peptides was observed using a confocal laser scanning microscope and quantitatively analyzed using flow cytometry. EGFR levels in the cell culture supernatants of cells treated with Vpr peptides were evaluated using an ELISA. Surface exposure of CRT on the tumor cell surface was observed using a confocal laser scanning microscope and quantitatively analyzed using flow cytometry. The secretion levels of ATP from tumor cells were evaluated using an ATP assay kit. HMGB1 release was evaluated using an ELISA. Mouse (Male C57BL/6 mice aged 4 weeks) MC38 and LLC bilateral subcutaneous tumor models were established to evaluate the therapeutic effects of Vpr peptides through in situ vaccination. Proteomic analysis was performed to explore the mechanism of anti-tumor activity of Vpr peptides. Results: Four Vpr peptides were designed and synthesized, with P1 and P4 exhibiting cytotoxic effects on tumor cells, inducing apoptosis and immunogenic cell death. In mouse tumor models, in situ vaccination with Vpr peptide significantly inhibited tumor growth and activated various immune cells. High-dose P1 monotherapy demonstrated potent anti-tumor effects, activating DCs, T cells, and macrophages. Combining ISV of P1 with a CD47 inhibitor SIRPαFc fusion protein showed potent distant tumor suppression effects. Proteomic analysis suggested that Vpr peptides exerted anti-tumor effects by disrupting tumor cell morphology, movement, and adhesion, and promoting immune cell infiltration. Conclusions: The designed Vpr peptides show promise as candidates for in situ vaccination, with significant anti-tumor effects, immune activation, and favorable safety profiles observed in mouse models. In situ vaccination with Vpr-derived peptides represents a potential approach for cancer immunotherapy. Full article

Background/Objectives: For viral entry into host cells, the spike (S) protein of coronavirus (CoV) uses its S1 domain to bind to the host receptor and S2 domain to mediate the fusion between virion and cellular membranes. The S1 domain acquired multiple mutations as the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) evolved to give rise to Variant of Concerns (VOCs) but the S2 domain has limited changes. In particular, the stem helix in S2 did not change significantly and it is fairly well-conserved across multiple beta-CoVs. In this study, we generated a murine mAb 7B2 binding to the stem helix of SARS-CoV-2. Methods: MAb 7B2 was isolated from immunized mouse and its neutralization activity was evaluated using microneutralization, plaque reduction and cell–cell fusion assays. Bio-layer interferometry was used to measure binding affinity and AlphaFold3 was used to model the antibody–antigen interface. Results: MAb 7B2 has lower virus neutralizing and membrane block activities when compared to a previously reported stem helix-binding human mAb S2P6. Alanine scanning and AlphaFold3 modeling reveals that residues K1149 and D1153 in S form a network of polar interactions with the heavy chain of 7B2. Conversely, S2P6 binding to S is not affected by alanine substitution at K1149 and D1153 as indicated by the high ipTM scores in the predicted S2P6-stem helix structure. Conclusions: Our detailed characterization of the mechanism of inhibition of 7B2 reveals its distinctive binding model from S2P6 and yields insights on multiple neutralizing and highly conserved epitopes in the S2 domain which could be key components for pan-CoV vaccine development. Full article

MiaA is responsible for the addition of the isopentyl modification to adenine 37 in the anticodon stem loop of specific tRNAs in Escherichia coli. Mutants in miaA have pleotropic effects on the cell in E. coli and play a role in virulence gene regulation. In addition, MiaA is necessary for stress response gene expression by promoting efficient decoding of UUX-leucine codons, and genes with elevated UUX-leucine codons may be a regulatory target for i⁶A-modified tRNAs. Understanding the temporal nature of the i⁶A modification status of tRNAs would help us determine the regulatory potential of MiaA and its potential interplay with leucine codon frequency. In this work, we set out to uncover additional information about the synthesis of the MiaA. MiaA synthesis is primarily driven at the transcriptional level from multiple promoters in a complex operon. However, very little is known about the post-transcriptional regulation of MiaA, including the role of sRNAs in its synthesis. To determine the role of small RNAs (sRNAs) in the regulation of miaA, we constructed a chromosomal miaA-lacZ translational fusion driven by the arabinose-responsive P_BAD promoter and used it to screen against an Escherichia coli sRNA library (containing sRNAs driven by the IPTG-inducible P_Lac promoter). Our genetic screen and quantitative β-galactosidase assays identified CsrB and its cognate protein CsrA as potential regulators of miaA expression in E. coli. Consistent with our hypothesis that CsrA regulates miaA post-transcriptional gene expression through binding to the miaA mRNA 5′ UTR, and CsrB binds and regulates miaA post-transcriptional gene expression through sequestration of CsrA levels, a deletion of csrA significantly reduced expression of the reporter fusion as well as reducing miaA mRNA levels. These results suggest that under conditions where CsrA is inhibited, miaA mRNA translation and thus MiaA-dependent tRNA modification may be limited. Full article

Choosing the optimal first-line treatment for patients with advanced non-small cell lung cancer (NSCLC) with anaplastic lymphoma kinase (ALK) rearrangements can be challenging in daily practice. Although clinical trials with next-generation ALK-tyrosine kinase inhibitors (TKIs) have played a key role in evaluating their efficacy and safety, which patients benefit from a specific ALK-TKI may still be questioned. The methodological inconsistencies in these trials, which led to the inclusion of different patient populations, appear to have been inadequately addressed. ALK-rearranged NSCLC is a heterogeneous disease, and co-existing molecular alterations may affect the outcome. The questions explored in these trials appear insufficient to support a personalized approach to the first-line treatment, while defining long-term responders and early progressors would be clinically useful. This narrative review presents several considerations from oncologists’ and pathologists’ perspectives. We propose defining favorable and unfavorable features, such as histology, type of ALK fusion, co-existing molecular alterations, plasma circulating tumor DNA (ctDNA, performance status, and brain metastases, to help identify patients with lower and higher risk of progression. Consequently, the most potent ALK-TKI to date, Lorlatinib, may be considered as the first-line treatment for high-risk patients with unfavorable features, while sequencing of ALK-TKIs may be appropriate for low-risk patients with favorable features. Although ALK signal inhibition is critical in this disease, it may not be sufficient for clinical control due to de novo co-alterations. A more personalized approach to first-line therapy requires consideration of risk factors for each patient. Full article

Phase-separated membraneless biomolecular condensates in the cytoplasm and nucleus are now recognized to play a major role in modulating diverse functions in mammalian cells, and contribute to cancer pathogenesis through dysregulated function of condensates of transcription factors such as STAT3 and fusion oncoproteins. Oral cancer, the sixth most prevalent malignancy worldwide, in the absence of overt causes such as tobacco or alcohol, most frequently occurs in a U-shaped zone (floor of mouth, side of tongue, anterior fauces and retromolar region) reflecting the path of liquid transit through the mouth. The cellular basis for this “high-risk” zone and the biochemical mechanisms used by oral cells to combat repetitive tonicity and temperature stresses are incompletely understood. We had previously observed that at 37 °C, in OECM1 oral carcinoma cells, cytoplasmic condensates of antiviral human GFP-MxA GTPase disassembled within 1–2 min of exposure of cells to saliva-like one-third hypotonicity, and underwent “spontaneous” reassembly in the next 5–7 min. Moreover, hypotonic beverages (water, tea, coffee), investigated at 37 °C, triggered this condensate cycling. In the present studies we investigated whether this process was temperature sensitive, representative of cold vs. warm drinks. We observed a slowing of this cycle at 5 °C, and speeding up at 50 °C. The involvement in this disassembly/reassembly process of WNK-SPAK/OSR1 serine-threonine kinase pathway, best studied for regulation of water and Na, K and Cl influx and efflux in kidney tubule cells, was evaluated by us in oral cells using pathway inhibitors WNK463, WNK-IN-11 and closantel. The pan-WNK inhibitor WNK463 inhibited hypotonicity-driven condensate disassembly, while the SPAK/OSR1 inhibitor closantel markedly slowed reassembly. Unexpectedly, the WNK1-selective inhibitor (WNK-IN-11), triggered a dramatic and rapid (within 1 h) spheroid to fibril transition of GFP-MxA condensates in live cells, but without affecting MxA antiviral function. The new data suggest a novel hypothesis for the anatomic localization of oral cancer in the U-shaped “high-risk” zone in the mouth: dysfunction of biomolecular condensates in oral cells along the beverage transit pathway through the mouth due to repetitive tonicity and temperature stresses that might underlie a prooncogenic progression. Full article