Search Results (1,218)

Bluetongue virus (BTV), the prototype of the genus Orbivirus, infects livestock, causing high morbidity and mortality and impacting global trade. BTV is a non-enveloped, double-capsid virus, composed of seven structural proteins and a genome of 10 double-stranded RNA segments. This manuscript highlights our group’s recent findings on the molecular and structural mechanisms underlying BTV entry and assembly during replication. Viral entry is a stepwise, pH-dependent process. The outermost protein, VP2, attaches to sialic acids and senses the acidic pH of early endosomes, triggering their dissociation. Subsequently, the second outer capsid protein, VP5, undergoes major changes in late endosomes, forming a membrane-penetrating pore that releases the transcriptionally active inner core into the host cytoplasm. Core assembly also proceeds stepwise and requires the accurate packaging of 10 positive-sense RNA segments. These segments form an RNA–RNA interaction network independent of viral proteins, beginning with the smaller segments and guiding the complete genome assortment. The small capsid protein, VP6, interacts with VP3 to facilitate RNA encapsidation. While infectious cores assemble in vitro without non-structural proteins, NS2 is essential for the in vivo formation of viral inclusion bodies via liquid–liquid phase separation, concentrating viral components and promoting genome assembly. These comprehensive characterizations of BTV provide a foundation for future control strategies against related reoviruses. Full article

Hyperbranched poly(β-amino ester) (HPAE) is identified as a unique non-viral carrier capable of sustaining high-efficiency transfection under elevated plasmid concentrations, overcoming the aggregation and toxicity limitations of conventional lipid and PEI reagents. We demonstrate that transfection enhancement is driven by concentration-dependent synergism between membrane accumulation and endosomal escape. Guided by this mechanism, a half-volume transfection strategy was established to transiently elevate plasmid concentration without compromising cell viability, enabling superior lentivirus yield and purity. These findings define plasmid concentration as a previously overlooked regulatory axis in nanoparticle-mediated gene delivery and position HPAE as a high-performance platform for scalable therapeutic vector production. Full article

Lipid nanoparticles (LNPs) have become an important platform for the delivery of RNA therapeutics, including messenger RNA (mRNA) and small interfering RNA (siRNA). However, most clinically approved LNP formulations exhibit strong liver tropism following systemic administration, which limits efficient delivery to extrahepatic tissues. This inherent biodistribution profile has therefore been recognized as a key challenge for expanding the therapeutic applications of RNA nanomedicine. Recent efforts have focused on engineering functionalized LNP systems to improve delivery specificity beyond the liver. Surface modification with targeting ligands—such as antibodies, peptides, and nucleic acid aptamers—can promote receptor-mediated uptake by specific immune cell populations, including macrophages, dendritic cells and T lymphocytes. In parallel, advances in lipid design have improved intracellular RNA delivery by facilitating endosomal escape. These developments have broadened the potential use of RNA nanomedicine for inflammatory disorders, including autoimmune diseases, neuroinflammation, and cardiovascular inflammation. Functionalized LNPs are also being investigated for in vivo engineering of immune cells. This review summarizes current strategies for designing functionalized LNP systems, highlights their emerging applications in immune and inflammatory diseases, and discusses key challenges for clinical translation. Full article

While current influenza vaccines often lack broad protection against antigenically drifted strains, some modified hemagglutinin (HA) protein antigens have shown promise in eliciting broadly neutralizing antibodies against conserved epitopes. During infection, the mildly acidic environment of the late endosome triggers irreversible HA conformational changes resulting in a post-fusion structure with altered antigenicity. While enhancing the stability of other structural class I viral fusion protein antigens has been instrumental in improving the effectiveness of COVID-19 and RSV vaccines, the role of HA stability in influenza vaccine immunogenicity is relatively unclear. Here, we used the nucleoside-modified mRNA-LNP platform to test engineered HA antigens with specific acid-stabilizing mutations (E47K, K58I, R106K, and K153E) in the HA stalk. All mutations increased HA acid stability, but E47K and R106K did not increase immunogenicity. K153E and K58I, but not E47K and R106K, enhanced the cell-surface expression of the HA protein in vitro. In mice, K153E- and K58I-containing mRNA-LNP vaccines elicited increased neutralizing antibody titers against homologous virus. K153E conferred greater protection than wild-type vaccine against lethal heterologous A/PR/8/34 challenge at low doses (0.5–1.0 µg), despite the absence of neutralizing antibodies against the challenge strain. K153E also elicited greater expansion of antigen-specific antibody-secreting cells (ASCs) in the bone marrow, as well as cross-reactive T follicular helper (Tfh) cells in the spleen. For the vaccines studied, increased HA expression was a stronger correlate of mRNA-LNP enhancement than increased HA stability. Full article

Toxin A and B from Clostridioides difficile are the main pathogenicity factors for clinical symptoms of C. difficile infections. Receptor-mediated endocytosis and endosomal escape are required for targeting substrate proteins of the Rho-GTPase family. We previously reported that Toxin B (TcdB) affects endo-lysosomal transport and autophagic flux of target cells. These effects are independent from pathogenic Rho inhibition. Here, we aimed at further characterization of this event by immunofluorescent characterization of the vesicular structures that are affected. We found large aggregates of damaged endolysosomal structures positive for EEA1, LAMP1, CHMP4B and TcdB, as well as an increase in perinuclear concentration of non-mature autophagosomes (amphisomes) positive for SQSTM, Rab7, and LC3B. We investigated whether Rab7, a regulator of late endosome transport, is causative for decreased lysosome function. Although TcdB induced an increase in active Rab7, as tested by an RILP pull-down assay, inhibition of Rab7 did not prevent TcdB-induced decrease in cathepsin D as a surrogate for lysosome dysfunction. It also indicates that the observed increase in Rab7 positive amphisomes is secondary to lysosomal dysfunction. By applying an autoproteolytic deficient mutant of TcdB we proved that the release of the glucosyltransferase domain is mandatory for triggering all of these effects. This suggests that after membrane perforation the toxin remnants leave an open leak in endolysosomes affecting ion homeostasis. Investigation of all large clostridial glucosyltransferases and other toxins revealed lysosomal dysfunction as a general effect of many but not of all toxins that integrate into the endosome membrane. Full article

Background/Objectives: Lipid nanoparticles (LNPs) containing ionizable lipids represent the most advanced non-viral delivery vehicles and have become state-of-the-art carriers for RNA therapeutics. However, further improvements in endosomal escape efficiency and biodegradability are still needed, especially for nucleic acids with transient activity such as messenger RNA (mRNA) and transfer RNA (tRNA). Methods: In this study, a novel library of highly biodegradable ionizable lipids featuring thioester groups within the linker region was designed and synthesized, thereby expanding the chemical linker toolbox for future ionizable lipid development. Results: Comprehensive in vivo structure–activity relationship studies led to the identification of CP-LC-1272 as a lead candidate that markedly enhances endosomal escape and exhibits superior in vivo biodegradability, attributed to the high acid-lability of thioester bonds. LNPs containing CP-LC-1272 maintained in vivo activity after six months of storage in lyophilized form and demonstrated superior in vivo efficiency compared to SM-102 in mRNA expression studies, as well as similar protein restoration in a tRNA delivery model targeting premature stop-codon mutations. Conclusions: The rapid biodegradability of these thioester-activated ionizable lipids (TAILs) suggests a reduced risk of accumulation, with the potential to enable safe repeated dosing or high-dosage RNA therapies, positioning TAILs as a versatile and safe platform for next-generation RNA therapeutics. Full article

Gene therapy relies on safe and efficient delivery systems, yet traditional viral vectors and synthetic polymers often fail to meet these requirements due to immunogenicity and biocompatibility concerns. This review highlights self-assembling short peptides as a highly programmable and biocompatible non-viral platform uniquely positioned to overcome these translational bottlenecks. To provide a comprehensive overview of next-generation gene delivery, we systematically trace the trajectory from fundamental chemistry to clinical applications. First, we elucidate the supramolecular interactions and mechanisms driving peptide–nucleic acid co-assembly. Second, we outline concrete design strategies, detailing how sequence engineering and environmental responsiveness dictate the formation of optimized nanomorphologies. Third, we critically analyze how these nanocarriers navigate critical physiological and intracellular barriers, with a specific focus on cellular uptake, endosomal escape, and cargo release. Finally, we demonstrate the platform’s versatility in emerging frontiers, particularly mRNA vaccines and CRISPR/Cas9 gene editing. We conclude by identifying current obstacles to clinical translation and proposing future directions centered on multifunctional integration and stimuli-responsive design. Full article

The infection cycle of the Influenza A Virus (IAV) typically requires host factors to regulate replication and proliferation. However, the roles of these factors remain undiscovered. This study focuses on Sorting Nexin 10 (SNX10), which is involved in regulating membrane trafficking and endosomal stabilization. Our previous study identified that SNX10 facilitates the replication of human coronavirus OC43 through enhancing clathrin-mediated endocytosis. In our present study, we found that SNX10 significantly promoted IAV infection in host cells. The conditional knockout of Snx10 in mice lungs prolonged survival following IAV challenge. Mechanistically, SNX10 facilitated the production of acidic endosomal vesicles and promoted the accumulation of pro-viral autophagic structures, a process supported by the specific interaction between SNX10 and the viral NP and M2 protein of IAV. Blocking SNX10-mediated acidic endosomal vesicles and autophagosome formation demonstrated antiviral effects. Moreover, IAV infection increased SNX10 protein levels by suppressing its ubiquitination, suggesting that SNX10 could serve as a potential host-derived antiviral drug target. Full article

Two-pore channels (TPCs) are evolutionarily conserved intracellular cation channels found in both plants and animals, where they mediate ion fluxes across endomembrane compartments. While historically the plant channel was among the first plant ion channels to be characterized, thanks to the relative ease of applying the patch-clamp technique to isolated plant vacuoles, where it is localized, the functional properties of the two main human isoforms, HsTPC1 and HsTPC2, expressed in endosomal and lysosomal membranes, were elucidated much later. In plants, TPCs are typically represented by a single isoform, exemplified by AtTPC1 in the model plant Arabidopsis thaliana, which functions as a voltage-dependent, Ca²⁺-regulated channel. The physiological role of plant TPCs is not yet fully clarified, although evidence suggests that they may contribute to systemic signaling and stress responses. In humans, two main isoforms, HsTPC1 and HsTPC2, are expressed in endosomal and lysosomal membranes. Human TPCs are primarily regulated by the phosphoinositide PI(3,5)P₂ and display a high selectivity for Na⁺. However, these channels also appear as a non-selective cationic conductance when activated by the potent Ca²⁺-mobilizing messenger NAADP, likely through interaction with an accessory protein. Functionally, human TPCs are involved in endolysosomal trafficking, membrane fusion, and intracellular signaling, with emerging roles in immunity, metabolism, and disease. Overall, TPCs represent key components of intracellular ion homeostasis and cellular physiology; however, their precise regulatory mechanisms and integrated physiological roles remain only partially understood and, in several respects, are still elusive. Full article

Normal steps in uptake of non-heme iron by the gastrointestinal tract include ferrireduction and import across the apical enterocyte membrane by divalent metal transporter 1 (DMT1), responsible for the uptake of non-transferrin bound iron (NTBI). This metal import by the intestinal epithelium requires an acidic milieu generated by the proton pump H(+)/K(+) ATPase (ATP4). Gastrointestinal uptake of metal can be affected by altering the acid milieu (e.g., proton pump inhibitors). After metal uptake by enterocytes, ferroxidation and export of the metal by ferroportin (FPN) at the basolateral membrane leads to the export of iron bound to transferrin (Tf). In peripheral tissues, cellular uptake of circulating iron is mediated by receptor-mediated endocytosis of Tf-bound iron, with DMT1 transporting the metal out of the endosomal compartment under acidic conditions generated by the vacuolar H⁺-ATPase. Acidosis is frequently associated with inflammation. The two derangements have relevant consequences like improved solubilization of iron, increased expression of Dmt1, elevated Fe²⁺ uptake due to DMT1’s ability to cotransport H⁺, dissociation of Fe-Tf and hepcidin decreasing Fe export via FPN. These changes result in intracellular iron sequestration that frequently becomes noxious. Pharmacological strategies to inhibit NTBI transport are proposed to protect against iron overload associated with acidosis and inflammation. Full article

Exosomes, a major subpopulation of small extracellular vesicles (sEV), are conserved mediators of intercellular communication, yet the properties of their endosomal precursors, intraluminal vesicles (ILV), have not been systematically quantified across species or imaging modalities. This study systematically evaluates ILV sizes across diverse eukaryotic species and modalities while assessing their relationship to secreted sEV sizes. We carried out two complementary meta-analyses of ILV sizes based on transmission electron microscopy (TEM) and cryogenic electron microscopy (cryo-EM) data across species. This was followed by in situ assessment of sEVs secreted by HEK293T cells with TEM, nanoparticle tracking analysis and super-resolution microscopy characterization. Across species, imaging modalities, and cellular contexts, ILV sizes were under approximately 200 nm, with a mean diameter of 100.5 nm, overlapping with the size range of sEVs. This study addresses an existing knowledge gap by systematically evaluating ILV size across species and revealing an upper size limit of approximately 200 nm. Full article

siRNA, as a precise, specific, and highly effective gene-silencing therapy, has been extensively studied. Before reaching tumor cell targets, siRNA formulations must overcome multiple extracellular barriers, including clearance from the bloodstream, membrane impermeability, capture by the mononuclear phagocyte system (MPS), rapid renal excretion, endosomal escape, and precise recognition of target cells. These challenges limit siRNA’s clinical application. Consequently, various modifications have been applied to siRNA to enhance transfection efficiency, while researchers continue to pursue improved siRNA-targeting delivery systems. Nanotechnology offers a rational technical approach to address siRNA delivery. Nanoparticles can increase transfection efficiency while exhibiting lower cytotoxicity and reduced off-target effects. Various matrices have been employed to construct nanoparticles for targeted therapeutic delivery. This review briefly discusses siRNA nanoparticle delivery strategies, illustrates examples of various siRNA nanodelivery systems, such as lipid nanoparticles, polymeric siRNA nanoparticles, inorganic nanoparticles, hybrid nanoparticles, and conjugate-siRNA delivery systems, and introduces clinical trials of siRNA-loaded nanoparticles for cancer treatment, which can provide valuable references for further research and clinical application of siRNA nanoparticle delivery systems. Full article

Platelets are small circulating blood cells that mediate haemostasis and thrombosis. Platelets respond to vascular damage by adhesion, granule release, and aggregation. Healthy endothelial cells inhibit platelets through prostacyclin-induced cAMP signalling. Intracellular cAMP activates protein kinase A (PKA), a tetrameric kinase composed of two regulatory (R) and two catalytic (C) subunits. cAMP-binding triggers dissociation of C subunits from the PKA complex and phosphorylation of substrate proteins, which mediate platelet inhibition. The R subunits of PKA are known to be attached to A-kinase anchoring proteins (AKAPs), which enable subcellular compartmentalisation of cAMP signalling. Proteomics have identified 22 AKAPs in platelets, but only a few of these have been studied in detail. This review summarises current knowledge about platelet AKAPs, including studies done regarding other cells. Possible integration of AKAPs into platelet signalling is explored with a focus on subcellular localisation, interaction partners, and PKA-mediated substrate phosphorylation. As main platelet compartments, the plasma membrane, endosomes, mitochondria, the Golgi, the dense tubular system, and the cytoskeleton are considered. Potential roles of individual AKAPs in platelet inhibition are discussed, and open questions in the field are defined. Full article

Duchenne muscular dystrophy (DMD) is a severe X-linked neuromuscular disease (NMD) caused by loss-of-function mutations in the DMD gene. RNA-based therapies, especially antisense oligonucleotides (ASO)-mediated exon skipping and adenosine deaminase acting on RNA (ADAR)-guided RNA editing, have emerged as complementary approaches that modulate pre-mRNA splicing or correct transcripts without altering genomic DNA. Current phosphorodiamidate morpholino oligomer (PMO) drugs targeting exons 51, 53, and 45 provide mutation-class-specific benefit. At the same time, next-generation delivery strategies (e.g., peptide-conjugated PMOs (PPMOs), antibody–oligonucleotide conjugates (AOC), and endosomal-escape vehicles) aim to improve skeletal, cardiac, and diaphragm exposure. In parallel, RNA editing strategies offer a route to correct select nonsense or missense variants at the base level and may, in principle, restore near-native dystrophin expression. Meaningful translation of these modalities requires predictive large-animal models. A genome-edited microminipig (MMP) bearing DMD exon-23 mutations faithfully recapitulates hallmark features of human DMD. That includes early locomotor deficits, elevated serum creatine kinase (CK) and cardiac troponin T, progressive myocardial fibrosis, and a decline in left-ventricular ejection fraction (LVEF), while maintaining a manageable lifespan of approximately 30 months suitable for long-term studies. In particular, the MMP model provides a practical platform for addressing the persistent challenge of efficient therapeutic delivery to the heart and diaphragm through longitudinal dosing, imaging, and biopsy. In this review, we synthesize clinical progress in exon skipping, outline the promise of RNA editing, and integrate recent insights from Duchenne muscular dystrophy model for microminipigs (DMD-MMPs) as an advanced surrogate for preclinical development and translational evaluation. Full article

Neurodegenerative diseases share a mitochondrial–immune axis in which impaired oxidative phosphorylation reshapes neuronal metabolism and drives chronic inflammation. Complex I play a redox gatekeeper role at the coenzyme Q (CoQ) junction: catalytic defects, misassembly, or reverse electron transport over-reduce the CoQ pool, increase electron leak, and elevate ROS. How respiratory supercomplex plasticity (CI-CIII₂, CIII₂-CIV_n, or CI-CIII₂-CIV_n) modulates carrier channelling, flux control, and ROS propensity through dynamic reorganization of the electron transport chain is highlighted. Excess ROS damages lipids and mitochondrial DNA, promoting the release of mitochondrial damage-associated molecular patterns s that activate NLRP3 inflammasome signalling, cGAS-STING-dependent interferon programs, and endosomal TLR9 pathways, establishing feed-forward loops between mitochondrial injury and neuroinflammation. Disease-focused sections integrate evidence from Parkinson’s, Alzheimer’s, amyotrophic lateral sclerosis, and Huntington’s models, and map these mechanisms onto therapeutic opportunities spanning electron transport chain support, supercomplex stabilization, and consider mtDNA-sensing inflammatory nodes. Full article