Search Results (1,422)

Zika virus (ZIKV) was first discovered in Uganda’s Zika Forest in 1947. The early African viruses posed little or no health risk to humans. Since then, ZIKV has undergone extensive genetic evolution and adapted to humans, and it now causes a range of human diseases, including neurologically related diseases in adults and congenital malformations such as microcephaly in newborns. This raises a critical question as to why ZIKV has become pathogenic to humans, and what virological changes have taken place and enabled it to cause these diseases? This review aims to address these questions. Specifically, we focus on the ZIKV envelope (E) protein, which is essential for initiating infection and plays a crucial role in viral entry. We compare various virologic attributes of E protein between the ancestral African strains, which presumably did not cause human diseases, with epidemic strains responsible for current human pathogenesis. First, we review the role of the ZIKV E protein in viral entry and endocytosis during the viral life cycle. We will then examine how the E protein interacts with host immune responses and evades host antiviral responses. Additionally, we will analyze key differences in the sequence, structure, and post-translational modifications between African and Asian lineages, and discuss their potential impacts on viral infection and pathogenesis. Finally, we will evaluate neutralizing antibodies, small molecule inhibitors, and natural compounds that target the E protein. This will provide insights into the development of potential vaccines and antiviral therapies to prevent or treat ZIKV infections and associated diseases. Full article

Extracellular vesicles (EVs) contain bioactive substances and mediate a multitude of physiological functions. EVs can be found in most body fluids and are particularly abundant in semen. EVs have the potential to become a biomarker for the quality of boar semen. In this study, EVs were isolated from the semen of relatively young (10 months of age, Y-EVs) and old (30 months of age, O-EVs) duroc boars using ultracentrifugation. The isolated EVs were characterized using a transmission electron microscope, nanoparticle tracking analysis, and Western blotting. MicroRNA (miRNA) profiles and metabolomes were analyzed using high-throughput sequencing and liquid chromatography–mass spectrometry, respectively. The median particle sizes of Y-EVs and O-EVs were 151.3 nm and 162.1 nm, respectively. miR-148a-3p, miR-10b, miR-21-5p, miR-10a-5p, let-7a, etc., were identified as highly enriched miRNAs in seminal EVs of boars. Comparative analysis revealed 41 differentially expressed miRNAs and 132 differential metabolites between Y-EVs and O-EVs. Notably, 18 miRNAs were upregulated in O-EVs, such as miR-339-5p, miR-125a, miR-423-3p, and miR-29c, which were mainly enriched in endocytosis, focal adhesion, and adherens junction. KEGG pathway analysis further indicated that differential metabolites were enriched in glycerophospholipid metabolism. These results provide an insight into the functional roles of seminal EVs. Full article

Delta-9-tetrahydrocannabinol (Δ-9-THC or THC), the primary psychoactive constituent of cannabis, can lead to adverse health conditions, including mental health issues, brain impairment, and cardiac and respiratory problems. The amount of THC in cannabis has steadily climbed over the past few decades, with today’s cannabis having three times the concentration of THC compared to 25 years ago. Inhalation is a major route of exposure, allowing substances to enter the body via the respiratory tract. THC exposure causes cell death in the airway epithelium; however, the molecular underpinning of THC exposure-induced bronchial epithelial cell death is not clearly understood. To address the mechanisms involved in this process, the present study examined the cell viability, oxidative stress, lipid peroxidation, and transcriptional alterations caused by various concentrations of Δ-9-THC (0, 800, 1000, 1200, and 1500 ng/mL) in a human bronchial epithelial cell line (BEAS-2B) in vitro. Δ-9-THC exposure caused a significant dose-dependent decrease in cell viability after 24 h exposure. Transcriptome analysis showed a distinct dose-dependent response. HIF-1 signaling, ferroptosis, AMPK signaling, and immunogenic pathways were activated by Δ-9-THC-upregulated genes. Glutathione and fatty acid metabolic pathways were significantly altered by Δ-9-THC-dependent downregulated genes. Ingenuity Pathway Analysis (IPA) revealed several top canonical pathways altered by Δ-9-THC exposure, including ferroptosis, NRF-2-mediated oxidative stress response, caveolar-mediated endocytosis (loss of cell adhesion to the substrate), tumor microenvironment, HIF1alpha signaling, and the unfolded protein response pathway. Δ-9-THC-induced cell death was ameliorated by inhibiting the ferroptosis pathway, whereas treatments with ferroptosis agonist exacerbated the cell death process, suggesting that Δ-9-THC-induced bronchial epithelial cell death potentially involves the ferroptosis pathway. Full article

Antibody–drug conjugates (ADCs) represent a novel approach to cancer treatment. Enfortumab vedotin (PADCEV), as a prominent example, has demonstrated remarkable clinical efficacy. However, its ocular toxicity has raised concerns. This study aimed to explore the molecular mechanisms underlying PADCEV—induced ocular toxicity. SD rats, whose ocular structures are similar to those of humans, were selected to establish an ocular toxicity model to mimic the human response. In vitro experiments were conducted using human primary corneal epithelial cells, HCE-T. The results confirmed that nectin-4 plays a crucial role in the cellular uptake of PADCEV, and non-specific pinocytosis is also involved. Additionally, a variant was obtained by introducing point mutations in the Fc region of PADCEV, which was found to reduce corneal epithelial toxicity. The findings of this study not only deepen our understanding of ADC-induced ocular toxicity but also provide new insights into optimizing ADC design and enhancing treatment safety. Full article

Infectious spleen and kidney necrosis virus (ISKNV) is an emerging viral pathogen with an expanding host range, posing a significant threat to economically important fish species. In this study, we isolated the ISKNV strain responsible for disease outbreaks in Asian seabass (Lates calcarifer) and analyzed the transcriptomic profile of spleen tissues from experimentally infected fish. The phylogenetic analysis confirmed that the virus belongs to clade I of ISKNV. Next-generation sequencing identified differentially expressed genes, providing a comprehensive overview of the transcriptional landscape in the spleen of ISKNV-infected fish. The pathway analysis revealed complex host–virus interactions, impacting immune regulation, endocytosis, cell communication, cell cycle arrest, and programmed cell death. To further investigate these interactions, we analyzed relevant pathways in the Reactome database for Asian seabass, humans, and zebrafish, constructed a protein–protein interaction (PPI) network using STRING database, and identified hub genes using six different algorithms. This analysis revealed 69 key genes, including 41 hub genes and 28 key genes that connect different pathways or clusters within the PPI network. These findings provide new insights into the molecular mechanisms driving ISKNV infection in Asian seabass. Future research should focus on elucidating the regulatory functions of these key genes and their roles in ISKNV pathogenesis. Full article

Endocytosis is a specialized transport mechanism in which the cell membrane folds inward to enclose large molecules, fluids, or particles, forming vesicles that are transported within the cell. It plays a crucial role in nutrient uptake, immune responses, and cellular communication. However, many pathogens exploit the endocytic pathway to invade and survive within host cells, allowing them to evade the immune system and establish infection. Endocytosis can be classified as clathrin-mediated (CME) or clathrin-independent (CIE), based on the mechanism of vesicle formation. Unlike CME, which involves the formation of clathrin-coated vesicles that bud from the plasma membrane, CIE does not rely on clathrin-coated vesicles. Instead, other mechanisms facilitate membrane invagination and vesicle formation. CIE encompasses a variety of pathways, including caveolin-mediated, Arf6-dependent, and flotillin-dependent pathways. In this review, we discuss key features of CIE pathways, including cargo selection, vesicle formation, routes taken by internalized cargo, and the regulatory mechanisms governing CIE. Many viruses and bacteria hijack host cell CIE mechanisms to facilitate intracellular trafficking and persistence. We also revisit the exploitation of CIE by bacterial and viral pathogens, highlighting recent discoveries in entry mechanisms, intracellular fate, and host-pathogen interactions. Understanding how pathogens manipulate CIE in host cells can inform the development of novel antimicrobial and immunomodulatory interventions, offering new avenues for disease prevention and treatment. Full article

Internalization of nanoparticles (NPs), including nanoplastic, is one of the key factors determining their toxicity. In this work, we studied the toxicity and mechanisms of the uptake of model fluorescent polystyrene NPs (PS NPs) of three different sizes (30, 50, and 100 nm) in three human cancer cells lines; two originated from gut tissue (HT-29 and Caco-2) and one originated from liver tissue (Hep G2). Toxicity was measured by Neutral Red Assay (NRU), whereas mechanisms of uptake were studied using flow cytometry and different uptake inhibitors. The toxicity of the studied NPs followed a general rule observed for NPs—the smaller ones were more toxic than the larger ones. This relationship was dose dependent; however, the overall toxicity of the studied NPs was very low, despite the significant uptake of PS NPs. Although clathrin- and caveolin-dependent uptake is generally accepted as a major route of NP uptake, the inhibition of both mechanisms did not affect PS NP uptake in the cell lines studied in this work. Further experiments revealed that the major route of PS NP uptake in these cells is a scavenger receptor-mediated uptake. Full article

Adaptor protein (AP) complexes are critical components of the cellular membrane transport machinery. They mediate cargo selection during endocytosis and intracellular vesicular trafficking. Five AP complexes have been characterized (AP1-5), and together their roles extend to diverse cellular processes including the homeostasis of membranous organelles, membrane protein turnover, and immune responses. Human Immunodeficiency Virus type 1 (HIV-1) and other lentiviruses co-opt these complexes to support immune evasion and the assembly of maximally infectious particles. HIV-1 Nef interacts with AP1 and AP2 to manipulate intracellular trafficking and downregulate immune-related proteins such as CD4 and MHC-I. Vpu also co-opts AP1 and AP2, modulating the innate defense protein BST2 (Tetherin) and facilitating the release of virions from infected cells. The envelope glycoprotein (Env) hijacks AP complexes to reduce its expression at the cell surface and potentially support incorporation into virus particles. Some data suggest that Gag co-opts AP3 to drive assembly at intracellular compartments. In principle, targeting the molecular interfaces between HIV-1 proteins and AP complexes is a promising therapeutic approach. Blocking these interactions should impair HIV-1’s ability to produce infectious particles and evade immune defenses, leading to novel antivirals and facilitating a cure. Full article

Receptor-mediated endocytosis (RME) is a commonly recognized receptor internalization process of receptor degradation or recycling. However, recent studies have supported that RME is closely related to signal propagation and amplification from the plasma membrane to the cytosol. Few studies have elucidated the role of H₂O₂, a mild oxidant among reactive oxygen species (ROS) in RME and second messenger of signal propagation. In the present study, we investigated the regulatory function of H₂O₂ in early endosomes during signaling throughout receptor-mediated endocytosis. In mammalian cells with a physiological amount of H₂O₂ generated during epidermal growth factor (EGF) activation, fluorescence imaging showed that the levels of two activating phosphorylations on Ser⁴⁷³ and Thr³⁰⁸ of Akt were transiently increased in the plasma membrane, but the predominant p-Akt on Ser⁴⁷³ appeared in early endosomes. To examine the role of endosomal H₂O₂ molecules as signaling mediators of Akt activation in endosomes, we modulated endosomal H₂O₂ through the ectopic expression of an endosomal-targeting catalase (Cat-Endo). The forced removal of endosomal H₂O₂ inhibited the Akt phosphorylation on Ser⁴⁷³ but not on Thr³⁰⁸. The levels of mSIN and rictor, two components of mTORC2 that work as a kinase in Akt phosphorylation on Ser⁴⁷³, were also selectively diminished in the early endosomes of Cat-Endo-expressing cells. We also observed a decrease in the endosomal level of the adaptor protein containing the PH domain, the PTB domain, and the Leucine zipper motif 1 (APPL1) protein, which is an effector of Rab5 and key player in the assembly of signaling complexes regulating the Akt pathway in Cat-Endo-expressing cells compared with those in normal cells. Therefore, the H₂O₂-dependent recruitment of the APPL1 adaptor protein into endosomes was required for full Akt activation. We proposed that endosomal H₂O₂ is a promoter of Akt signaling. Full article

According to the current dogma, ER–Golgi transport is mediated by COPII-coated vesicles. However, numerous contradictions have emerged in this field. In this study, we demonstrate that Saccharomyces cerevisiae contains three distinct types of membrane spheres, with diameters of approximately 35–45 nm, 47–52 nm, and over 65 nm, respectively. The first type is Sso1-positive and primary associated with clathrin-positive endocytosis invaginations, which may function as exit sites for secretory soluble cargos. The second population is GOS1-positive and COPI-dependent. The third population represents secretory granules. Furthermore, we propose that several cornerstone studies supporting the COPII-vesicle model can have alternative interpretations. Our findings suggest that the predominant model of intracellular transport in Saccharomyces cerevisiae is the “kiss-and-run” mechanism. Full article

Prostate cancer is the most common tumor in men in developed countries and it often responds poorly to conventional treatments. Monoclonal antibody (MoAb) therapy, for this pathology, has grown tremendously in the past decades, exploiting naked and conjugated antibodies to cytotoxic payloads to form antibody drug conjugates (ADCs). Several studies have been carried out conjugating biomolecules against prostate-specific membrane antigen (PSMA), highly expressed in this tumor, to cytotoxic drugs. Nano-based formulations show high potential in targeted drug delivery to enhance the bioavailability of drugs. Our research aimed to evaluate the feasibility of setting up a nanoparticle-based multimodal tool for targeted drug delivery, describing the step-by-step approach and to perform a first screening of these fluorescent PEGylated silica nanoparticles employed in selective cancer cell targeting and killing. These nanoparticles featured a core–shell structure to contemporarily conjugate the antibody and the cytotoxic payload monomethyl auristatin E (MMAE) using a step-by-step approach. We compared the cytotoxic effect of this multimodal nanotool near the antibody-MMAE and free MMAE. We found a lower cytotoxicity effect of the nanoparticle-based construct compared to free drugs, likely because of the preservation of the previously observed receptor-mediated endocytosis. Nanomedicine is confirmed as a powerful alternative to organic drug delivery systems, even if some aspects, such as drug loading efficacy, release, scalable manufacturing and long-term stability, need to be deepened. Full article

Alzheimer’s disease and other neurodegenerative disorders are characterized by the accumulation of misfolded proteins, such as amyloid-beta, tau, and α-synuclein, which disrupt neuronal function and contribute to cognitive decline. Heparan sulfate proteoglycans, particularly syndecans, play a pivotal role in the seeding, aggregation, and spreading of toxic protein aggregates through endocytic pathways. Among these, syndecan-3 is particularly critical in regulating the internalization of misfolded proteins, facilitating their propagation in a prion-like manner. This review examines the mechanisms by which syndecans, especially SDC3, contribute to the seeding and spreading of pathological protein aggregates in neurodegenerative diseases. Understanding these endocytic pathways provides valuable insights into the potential of syndecans as biomarkers and therapeutic targets for early intervention in Alzheimer’s disease and other related neurodegenerative disorders. Full article

Background: Cancer ranks as a leading cause of death worldwide. It is urgent to develop intelligent co-delivery systems for cancer chemotherapy to achieve reduced side-effects and enhanced therapeutic efficacy. Methods: We chose oligo-hyaluronic acid (oHA, a low molecular weight of HA) as the carrier, and adriamycin (ADM) and paclitaxel (PTX) as the co-delivered drugs. The oHA-ss-PTX macromolecular prodrug was synthesized by introducing glutathione-stimuli-responsive disulfide bonds through chemical reactions. Then, we constructed ADM-loading micelles (ADM/oHA-ss-PTX) in one step by microfluidic preparation. The delivery efficacy was evaluated comprehensively in vitro and in vivo. The biocompatibility of ADM/oHA-ss-PTX was assessed by hemolysis activity analysis, BSA adsorption testing, and cell viability assay in endothelial cells. Results: The resulting ADM/oHA-ss-PTX micelles possessed a dynamic size (127 ± 1.4 nm, zeta potential −9.0 mV), a high drug loading content of approximately 21.2% (PTX) and 7.6% (ADM). Compared with free ADM+PTX, ADM/oHA-ss-PTX showed enhanced blood stability and more efficiently inhibited cancer cell proliferation. Moreover, due to the CD44-mediated endocytosis pathway, a greater number of ADM/oHA-ss-PTX micelles were absorbed by A549 cells than by oHA-saturated A549 cells. In vivo experiments also showed that ADM/oHA-ss-PTX micelles had excellent therapeutic effects and targeting ability. These results show that ADM/oHA-ss-PTX micelles were a promising platform for co-delivery sequential therapy in CD44-positive cancer. Conclusions: In conclusion, these results convincingly demonstrate that ADM/oHA-ss-PTX micelles hold great promise as a novel platform for co-delivering multiple drugs. Their enhanced properties not only validate the potential of this approach for sequential cancer therapy in CD44-positive cancers but also pave the way for future clinical translation and further optimization in cancer treatment. Full article

Liver sinusoidal endothelial cells (LSECs) play a crucial role in hepatic homeostasis, clearance, and microcirculatory regulation. Their fenestrations—patent transcellular pores—are essential for proper liver function, yet disappear in pathological conditions such as liver fibrosis and inflammation through a process known as defenestration. Defenestrated sinusoids are often linked to the liver stiffening that occurs through mechanotransduction-regulated processes. We performed a detailed characterization of polyacrylamide (PAA) hydrogels using atomic force microscopy (AFM), rheometry, scanning electron microscopy, and fluorescence microscopy to assess their potential as biomimetic substrates for LSECs. We additionally implemented AFM; quantitative fluorescence microscopy, including high-resolution structured illumination microscopy (HR-SIM); and an endocytosis assay to characterize the morphology and function of LSECs. Our results revealed significant local variations in hydrogel stiffness and differences in pore sizes. The primary LSECs cultured on these substrates had a range of stiffnesses and were analyzed with regard to their number of fenestrations, cytoskeletal organization, and endocytic function. To explore mechanotransduction in inflammatory liver disease, we investigated LSECs from a genetic model of systemic inflammation triggered by the deletion of Mcpip1 in myeloid leukocytes and examined their ability to restore their fenestrations on soft substrates. Our study demonstrates the beneficial effect of soft hydrogels on LSECs. Control cells exhibited a similar fenestrated morphology and function compared to cells cultured on plastic substrates. However, the pathological LSECs from the genetic model of systemic inflammation regained their fenestrations when cultured on soft hydrogels. This observation supports previous findings on the beneficial effects of soft substrates on LSEC fenestration status. Full article

Nasal nanodrug delivery has gained prominence as a non-invasive method for administering therapeutic agents to the brain. However, the limited nasal cavity volume and the low drug loading capacity of nanoparticles contribute to a reduced accumulation of the drug within the brain tissue. Therefore, the aim of the present study was to investigate the role of the drug delivery combination “transnasal route + nanoparticle drug delivery system + chemical osmosis technology” in promoting drug accumulation in the brain. We constructed an in vitro olfactory sheath cell model based on the direct nose–brain pathway and a vascular endothelial cell model based on the indirect pathway, and investigated the transport behaviors and mechanisms of Poly(lactic-co-glycolicacid)-Nanoparticles (PLGA-NPs) in combination with two terpene aroma constituents (menthol and curcumol). Menthol and curcumol significantly improved the intracellular accumulation of PLGA-NPs, which may be related to changes in the endocytosis pathway and intercellular tight junction proteins. Meanwhile, the results of laser scanning confocal microscopy and atomic force microscopy showed that menthol and curcumol disrupted different tight junction proteins of vascular endothelial cells, and the biomechanical properties (e.g., rigidity and roughness) of the olfactory sheath cells and vascular endothelial cell cytomembranes were also greatly changed. The delivery system of “transnasal route + nanoparticle drug delivery system + chemical osmosis technology” has great potential for intranasal delivery of drugs for the treatment of brain diseases. Full article