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Niu, Y.

Publications and source records attributed to Niu, Y..

At least 19 recordsLinked to original sources

Structural Adaptability in HIV-2 Vif Drives Broad Antagonism of APOBEC3G

APOBEC3G (A3G), a restriction factor, is a barrier for zoonosis and targeted for degradation by the lentiviral protein Vif. Human Immunodeficiency Virus Type 1 (HIV-1) and HIV-2 arose from transmissions of lentiviruses from Old World monkeys to hominid primates. While HIV-1 Vif needed to adapt to specific residues in the arms race interface with A3G, HIV-2 Vif has greater tolerance for diversity there. Here, our cryo-EM structure of HIV-2 Vif and human A3G allows us to explore the mechanism underlying HIV-2 Vif broad specificity. While HIV-2 Vif does bind the arms race interface on A3G, HIV-2 Vif encodes tryptophans with low backbone stability to engage another interface on A3G. We propose a model where flexible loops in HIV-2 Vif undergo conformational selection to recognize diverse A3Gs, whereas the equivalent loops in HIV-1 Vif are preorganized to bind hA3G.

biophysics↗

FFPE-CUTAC: A Single Assay, Multiple Layers

Background: Archival biobanks of formalin-fixed paraffin-embedded (FFPE) specimens represent a vast and underused resource for retrospective molecular studies linked to clinical follow-up. However, fixation-induced chemical modification and nucleic acid fragmentation limit scalable genomic and transcriptomic profiling. FFPE-CUTAC (Cleavage Under Targeted Accessible Chromatin) is an RNA polymerase II-targeted DNA assay specifically designed to profile regulatory activity in FFPE tissue. Here, we assess its archival robustness, information content, compatibility with RNA-seq, and ability to recover copy-number alterations. Results: In meningioma and breast cancer cohorts, we benchmarked FFPE-CUTAC against matched fresh-frozen RNA-seq, FFPE RNA-seq and FFPE whole-genome sequencing. For FFPE specimens spanning up to 25 years, FFPE-CUTAC showed no systematic collection-year-associated decline in library yield or signal-quality metrics. In contrast, FFPE RNA-seq is more affected by the FFPE tissue degradation and specimen age on read composition, gene-body coverage, and gene detection. By measuring RNA polymerase II occupancy on chromatin rather than mature RNA abundance, FFPE-CUTAC is less constrained by transcript half-life, polyadenylation or transcript-capture design. FFPE-CUTAC extends beyond gene regions to non-coding regulatory elements, while the shared gene-level signals supported its integration with existing RNA-seq cohorts for large-scale, long-term clinical association study. FFPE-CUTAC libraries also retain DNA dosage information and can be used to recover chromosome-arm gain, loss and intact states with 96% concordance to matched whole-genome sequencing. Conclusions: By converting routinely preserved pathology sections into integrated regulatory and copy-number profiles, FFPE-CUTAC provides a practical foundation for constructing clinically annotated disease maps to support molecular stratification, prognostic modeling and treatment-association studies.

cancer biology↗

Structural characterization the LlaI anti-phage defense system reveals insights into the evolution of nucleotide specificity and the organization of DNA binding in McrBC restriction complexes

Canonical McrBC enzymes are nucleotide-powered, motor-driven endonucleases that bind and cleave modified bacteriophage DNA. Non-canonical McrBC homologs like LlaI and BsuMI are distinguished by a unique three-gene organization and the ability to target DNA site-specifically. Here, we report the atomic-resolution crystal structures of the DNA-binding module LlaI.R1 and AAA+ motor LlaI.R2 from the Lactococcus lactis LlaI anti-phage defense system. The crystallized LlaI.R2 hexamer traps two distinct active site conformations that correlate to different states of the nucleotide hydrolysis cycle and reveal that the organization of the critical catalytic machinery present in canonical McrB homologs is also conserved in non-canonical R2 proteins. Although canonical McrB homologs are strictly GTP-specific, we find that the R2 proteins from LlaI and BsuMI do not discriminate between different nucleotides, even when in complex with their respective R1 partners. Using mutagenesis, we define surfaces on the LlaI.R1 structure that are critical for DNA-binding and interaction with LlaI.R2. These observations support computational modelling of the assembled LlaI restriction system bound to DNA. Together, our data provide new insights into the evolution of nucleotide specificity in McrBC restriction complexes and the molecular mechanisms governing McrBC-catalyzed DNA translocation and cleavage.

biochemistry↗

Plasma membrane PI4P recruits SNAP47 to mediate SNARE-dependent AMPAR exocytosis during synaptic potentiation

The synaptic delivery of the AMPA-type glutamate receptors (AMPARs) is crucial for longterm potentiation (LTP) of excitatory synapses, yet the mechanisms underlying neuronal activity-dependent AMPAR exocytosis at the plasma membrane (PM) remain unclear. We previously demonstrated that the PM synthesis of the phosphoinositide PI4P is enhanced upon LTP induction and that PM PI4P, not PI(4,5)P2, is required for activity-induced AMPAR exocytic trafficking. Here, we show that AMPARs are exocytosed at PI4P-enriched dendritic PM microdomains in potentiated hippocampal neurons. The Q-SNARE SNAP47 binds PI4P via its pleckstrin homology (PH)-like domain. This interaction recruits SNAP47 to the PM, promoting the exocytic fusion of AMPAR vesicles through the SNAP47-Syntaxin-3-VAMP2 SNARE complex. In the hippocampus, the SNAP47-PI4P interaction is necessary for both LTP and long-term memory. Our findings reveal a mechanistic role for PI4P in mediating activity-dependent, SNARE-driven fusion of AMPAR exocytic vesicles with the PM.

neuroscience↗

The Capillary endothelial cell-governed niche sustains angiogenesis in proliferating infantile hemangioma via multilayer stromal support

Infantile hemangioma (IH), the most common benign vascular tumor in infants, is characterized by the aberrant proliferation of hemangioma endothelial cells (HemECs) and excessive angiogenesis. However, it is unclear how the tumor microenvironment sustains these active angiogenic signals. We performed single-cell RNA sequencing and spatial transcriptomic to profile 30 samples from proliferating IH, involuting IH, and normal skin. The results indicated that HemECs comprised distinct subpopulations. Among them, capillary endothelial cells (Cap.ECs) had an immature phenotype and functioned as the core drivers of IH. The endothelial-to-mesenchymal transition endothelial cells (endoMT-ECs) secreted collagen and engaged in CD44-mediated crosstalk with Cap.ECs to construct the angiogenesis-active niche in the tumor microenvironment (TME) of proliferating IH. Blockade of CD44-mediated intercellular communication effectively suppresses the angiogenesis of HemECs and promotes tumor regression. Beyond the endothelial layer, pericytes tightly enveloped Cap.ECs, with SERPINE2+ subtypes sustaining their angiogenic activity via ANGPT signaling. Pseudotime trajectory analysis revealed that the mesenchymal stem cells (MSCs)-enriched niche serves as a progenitor pool for Cap.ECs in proliferating IH. Our findings thus revealed that IH progression relies on CD44-mediated endoMT-EC-Cap.EC crosstalk and on both pericyte and MSC niches to sustain angiogenesis. HIGHLIGHTSO_LICapillary endothelial cells drive infantile hemangioma progression, with pericytes tightly ensheathing them. C_LIO_LICD44-mediated capillary and endoMT-derived endothelial cells crosstalk construct the angiogenic-active niche in the tumor microenvironment of proliferating infantile hemangioma. C_LIO_LIThe MSC-enriched niche provides a progenitor pool for the capillary endothelial cells in proliferating infantile hemangioma. C_LI

cancer biology↗

Imaging-Based Age- and Sex-specific Cardiovascular and Skeletal Phenotypes in Fbn1C1041G/+ Mice

Marfan syndrome is a multisystem connective tissue disorder with age-dependent and sex-dependent phenotypic variability. This study characterized early cardiovascular, valvular, transmitral flow, and skeletal changes in Fbn1C1041G/+ mice. Male and female wild-type and Fbn1C1041G/+ mice were examined from 4 to 20 weeks of age. Transthoracic echocardiography was used to measure aortic root and ascending aortic diameters, anterior mitral leaflet length, and mitral inflow Doppler parameters. Lateral X-ray imaging was used to quantify kyphosis angle. Fbn1C1041G/+ mice of both sexes developed progressive aortic dilation, with earlier and broader aortic root involvement in males and delayed annular dilation in females. Anterior mitral leaflet elongation was detected from 8 weeks in males and at 20 weeks in females. In contrast, reduced E-wave velocity and E/A ratio were present from 4 weeks in both sexes, without changes in A-wave velocity. Kyphosis was detectable earlier in females than in males. These findings show that early Fbn1-related phenotypes follow organ-specific and sex-dependent temporal patterns, supporting age-resolved and sex-stratified assessment in preclinical Marfan syndrome studies.

pathology↗

Charting Cervical Spinal Cord Morphometry Across the Lifespan

Spinal cord morphometry provides essential biomarkers of neurological health, but clinical interpretations are confounded by inter-subject variability and a lack of normative references across the full human lifespan. We address this gap by generating the first comprehensive lifespan charts for cervical spinal cord morphometry. We leveraged 30 population-based brain MRI datasets, aggregating 78,269 scans from 41,042 individuals (ages 0-100) whose imaging protocols included cervical cord coverage. To overcome contrast variability, we employed a state-of-the-art contrast-agnostic deep learning segmentation method, extracting cross-sectional area (CSA), anteroposterior (AP) and right-left (RL/transverse), and shape indices (compression ratio, eccentricity, and solidity) from C1 to C7. Normative trajectories were modeled using Generalized Additive Models for Location, Scale, and Shape (GAMLSS). The resulting charts reveal distinct non-linear lifespan changes: rapid growth through childhood and adolescence, peak maturation occurring in early-to-mid adulthood (e.g., mid-30s for CSA), followed by gradual decreases. Significant regional variations along the cervical cord and consistent sex differences (males > females for size metrics) were quantified. Spinal cord trajectories showed strong temporal coupling with brain white matter and brainstem volumes, suggesting integrated CNS development and aging. These lifespan charts provide a robust normative framework, enabling age- and sex-specific centile scoring of individual spinal cord morphometry. This resource offers a critical tool for differentiating typical variation from pathological changes, enhancing the clinical utility of spinal cord MRI in studies of development and neurodegeneration.

neuroscience↗

Hepatic HIF2α modulates extra-hepatic disease-associated phenotypes during metabolic dysfunction-associated steatotic liver disease

Metabolic dysfunction-associated steatotic liver disease (MASLD) afflicts more than one-third of adults globally, contributing significantly to an increased cardiovascular disease risk. Further, patients with severe liver disease experience muscle weakness (sarcopenic obesity) and fatigue. Hypoxia-inducible factor 2 (HIF2) accumulates in the livers of MASLD patients and has been implicated in disease progression. Here we sought to understand the role of hepatic HIF2 in mediating hepatic and extra-hepatic features of MASLD. Using a well-validated obese mouse model of MASLD, we investigated the impact of hepatocyte-specific HIF2 deletion (hHIF2-/-) on hepatic, cardiac and skeletal muscle metabolism, and cardiac function. Over 28 weeks, mice were exposed to a high-fat, high-fructose, high-cholesterol (GAN) diet, which induced obesity alongside hepatic steatosis, fibrosis and inflammation. In contrast to observations in lean mouse models of liver disease, hHIF2-/- did not protect against MASLD, despite greater hepatic NADH-supported mitochondrial respiration and higher intracellular sphingomyelin levels. Instead, in the hearts of GAN-fed mice, hHIF2-/- caused diacylglycerol accumulation independent of diet, accumulation of long-chain acyl-carnitines and exacerbation of ceramide accumulation. Langendorff-perfused hearts from hHIF2-/- mice showed systolic and diastolic dysfunction, including 24% lower left ventricular developed pressure and 34% lower maximal rate of relaxation (dP/dtmin). However, isolated hearts from hHIF2-/- mice were protected against MASLD-associated sympathetic dominance, determined using autonomic receptor agonist stimulation. Both GAN-feeding and hHIF2-/- were associated with lower lean mass (14% and 5.4% lower than respective controls), whilst hHIF2-/- enhanced OXPHOS-associated protein levels in gastrocnemius muscle. Overall, hHIF2-/- resulted in detrimental extra-hepatic effects, including myocardial lipid accumulation, impaired cardiac function, and loss of whole-body lean mass, with no apparent protection against MASLD disease progression.

physiology↗

ALKBH5 Promotes Hepatic Gluconeogenesis via m6A-mediated Stabilization of Ogt mRNA

Excessive hepatic glucose production is a hallmark of fasting hyperglycemia in type 2 diabetes mellitus, yet the epitranscriptomic mechanisms that sustain this dysregulation remain incompletely understood. Here, we show that dexamethasone/forskolin-induced gluconeogenic activation triggers widespread remodeling of RNA m6A methylation in mouse primary hepatocytes. Among the m6A regulators examined, the demethylase ALKBH5 is robustly induced both in vitro and in fasted livers. This induction is mediated by the glucocorticoid receptor, which binds to the Alkbh5 promoter and activates its transcription. Functionally, ALKBH5 overexpression enhances gluconeogenic gene expression and glucose production, whereas both global and hepatocyte-specific Alkbh5 knockout mice exhibit suppressed hepatic gluconeogenesis. Mechanistically, we identify Ogt as a primary downstream target, defining an ALKBH5-OGT epitranscriptomic axis in hepatocytes. ALKBH5 demethylates and stabilizes Ogt mRNA, thereby elevating OGT expression and promoting gluconeogenic gene expression. Consistently, the pro-gluconeogenic effects of ALKBH5 are largely abrogated by OGT knockdown. Finally, pharmacological inhibition of ALKBH5 with 18l effectively improves glucose tolerance and suppresses hepatic gluconeogenesis in both wild-type and db/db mice. Together, these findings reveal a glucocorticoid-responsive epitranscriptomic mechanism whereby ALKBH5 stabilizes Ogt mRNA to drive gluconeogenesis and highlight ALKBH5 as a promising therapeutic target for type 2 diabetes mellitus.

molecular biology↗

Super-resolution single-cell spatial atlas of plant de novo regeneration

Plant de novo regeneration, a capacity absent in animals, relies on stem-cell-niche formation rather than pre-existing reservoirs. Growth hormones such as auxin and cytokinin, together with numerous genetic regulators, participate in regeneration, but the architectural principles coordinating extensive cellular reprogramming at the individual-cell scale remain elusive. Using super-resolution multimodal spatial transcriptomics to 1.16 million cells, we tracked tomato regeneration across temporal intervals from wounding to organogenesis. Datasets are available at http://www.single-cell-spatial.com.

cell biology↗

Intra-annual precipitation variability mutes or magnifies the impact of wet and dry years on plant biomass.

As the atmosphere warms, both the amount and timing of precipitation are changing, but how those two trends interact to influence plant growth remains unresolved. Using 5-15 years of data from 48 globally distributed grassland sites, we quantified how the temporal distribution of precipitation within the year (evenness) interacts with annual precipitation amount and nutrient limitation to influence plant biomass. Annual precipitation anomalies had a large influence on plant biomass when intra-annual precipitation was more evenly distributed (frequent small events) and little impact when less even (infrequent large events). This relationship was consistent across aridity gradients and nutrient limitations and strongest in systems with warm wet seasons. Our work shows that the response of plant systems to changes in annual precipitation amount are largely dependent on how evenly it is temporally distributed.

ecology↗

Analytic Bounds on GAMLSS Model Variability of Normative White Matter Brain Charts

Brain charts, or normative models of quantitative neuroimaging measures, can identify trajectories of brain development and abnormalities in groups and individuals by leveraging large populations. Recent work has extended these brain charts to model microstructural and macrostructural features of white matter. Assessments of variance for these brain charts are necessary to determine whether the models being used for these data are stable. We implement an analytic approach to characterize variability of the parameters in previously released brain charts created using the generalized additive models for location, scale, and shape (GAMLSS) framework. Additionally, we empirically validate the accuracy of each analytic model through a comparison to a bootstrapping approach from 0.2 to 90 years of age. We find that across all models, the analytic coefficient of variation (COV) remains below 5% for ages greater than 0.25 years, with the maximum empirical observed COV reaching 7% at 0.2 years of age. Further, the empirical assessment shows high agreement with the analytic assessment, with COV estimates averaged across the lifespan for all models having a Pearson correlation coefficient of 0.776 and a mean difference of 4 x 10-4. Both methods exhibit volume and surface area as the features with the largest average COV for the majority of tracts. However, the analytic assessment yields axial diffusivity as the feature most frequently having the smallest COV, whereas the corresponding feature for the empirical assessment is average length. These results suggest that the analytic approach overestimates model stability for WM brain charts when the COV is low and that the validation method is suitable for assessing whether GAMLSS models are unstable.

bioengineering↗

Developmental Hypoxia Increases Susceptibility to Cardiac Ventricular Arrhythmias in Adult Offspring

Ventricular arrhythmias are the leading cause of sudden cardiac death. It is well-established that environmental factors contribute to the origin and penetrance of ventricular arrhythmic disorders. However, to our knowledge, no studies have considered the role of the intrauterine environment. In this study, we investigated the long-term effects of fetal hypoxia on ventricular arrhythmia susceptibility. Pregnant Wistar rats were assigned to normoxia (21% O2) or hypoxia (13% O2 between gestational days 6-20), and offspring were raised to 6 months. Hearts were isolated and loaded with the fluorescent calcium- and voltage-sensitive indicators, Rhod-2 and RH237, respectively. Optical mapping was performed while the left ventricle was burst paced (10-20hz) to induce arrhythmias. Hearts isolated from adult offspring exposed to fetal hypoxia were more susceptible to arrythmia during burst pacing, compared to controls. This phenotype was associated with prolonged Ca2+ transients and action potentials, an increased frequency of Ca2+ waves and delayed after depolarisations, as well as lower gene and protein expression of the sarcoplasmic reticulum Ca2+ ATPase. Collectively, our data shows that fetal hypoxia can programme ventricular arrhythmia sensitivity in adulthood, driven by abnormalities in excitation-contraction coupling. This is the first evidence that some ventricular arrhythmias may have a developmental origin, highlighting pregnancy as a potential window for early preventive intervention.

developmental biology↗

Maternal cardiometabolic dysfunction and fetal sex-specific alterations to uterine vascular reactivity in an ovine model of diet-induced obesity during pregnancy

Obesity during pregnancy is at pandemic proportions and predisposes women to pre- and postnatal cardiovascular dysfunction. The mechanisms underlying this maternal cardiovascular vulnerability remain unclear, partly due to a lack of translatable models capable of longitudinal in vivo cardiovascular monitoring. Here, we characterise a novel ovine model of maternal diet-induced obesity during pregnancy. Ewes were fed a control (CON) or obesogenic (OB; ad libitum concentrates) diet for 60 days pre-pregnancy and throughout gestation. Pregnant ewes were surgically instrumented with vascular catheters and Transonic flow probes using the wireless CamDAS system, which measured maternal cardiovascular function near term in free-moving ewes. Uterine artery vasoreactivity was assessed ex vivo by in vitro wire myography. OB ewes entered pregnancy 30% heavier than controls (P<0.003) and were hyperglycaemic, hyperinsulinemic, and hyperlipidaemic during pregnancy, relative to CON ewes (all P<0.05). OB ewes had elevated haematocrit and haemoglobin across pregnancy, and were hypertensive near term, with an increase in basal femoral artery blood flow, and elevated peripheral oxygen and glucose delivery (all P<0.05). OB mothers carrying a female fetus showed increased uterine artery vascular resistance in vivo (P<0.005) and reduced smooth muscle-dependent vasorelaxation ex vivo (P<0.05) relative to CON. Conversely, OB mothers carrying a male fetus showed greater NO-independent mechanisms mediating the uterine vasodilator response to methacholine ex vivo (P<0.001). Collectively, this study characterises a robust model of maternal obesity during pregnancy that offers clinical translational potential and highlights fetal sex-specific changes to uterine artery function. Key points summaryO_LIObesity during pregnancy is increasingly common and predisposes women to cardiovascular dysfunction during pregnancy and long after birth, but the specific mechanisms underlying this remain unclear. C_LIO_LIWe developed a novel ovine model of diet-induced obesity during pregnancy that displays maternal hypertension, elevated haemoglobin, metabolic dysfunction and alterations in uterine and peripheral blood flow and nutrient delivery near term. C_LIO_LIMothers with obesity carrying a female fetus had elevated uterine vascular resistance in vivo and reduced uterine artery smooth muscle-dependent vasodilator reactivity ex vivo. C_LIO_LIMothers with obesity carrying a male fetus showed no effect on uterine vascular resistance in vivo, but greater NO-independent mechanisms mediating the uterine vasodilator response to methacholine ex vivo. C_LIO_LIThese findings highlight that fetal sex may influence maternal cardiovascular function during obese pregnancy. C_LI

developmental biology↗

Elucidating Odorant Masking Effects in Food Matrices Through Olfactory Receptor-Based Profiling

Dynamic interactions among aroma compounds, especially odorant masking, constitute a key determinant of the intricate flavor profiles of thermally processed foods. However, the molecular and receptor-level mechanisms governing mutual odor suppression remain largely unclear. This study investigated the reciprocal sensory masking between 2,3,5-trimethylpyrazine and L-menthol via systematic sensory evaluation. Olfactory receptor screening identified OR5K1 as the responsive receptor for 2,3,5-trimethylpyrazine (EC50 = 27.67 {+/-} 2.02 mol/L) and OR2W1 as the functional receptor for L-menthol (EC50 = 22.69 {+/-} 3.85 mol/L). Consistently, quantitative cellular response assays further validated that 2,3,5-trimethylpyrazine and L-menthol exert mutual inhibitory effects on their respective receptors, as evidenced by the significant inhibition of receptor signaling. Moreover, molecular modeling predicted that 2,3,5-trimethylpyrazine and L-menthol competitively occupy the same orthosteric pocket via analogous binding conformations. These results provide novel receptor-level insights into odorant inhibitory effects, connecting sensory perception to molecular recognition, and deepen mechanistic understanding of flavor perception.

cell biology↗

Single-cell Tree-based Model for Genomic-Disease Association

The rapid maturation of single-cell multi-omics technologies has enabled unprecedented resolution for mapping disease states and identifying disease-associated biomarkers. In practice, biomarkers are often discovered through differential detection that treat genomic features as independent contributors to phenotypes, while the combinatorial interactions that drive clinical outcomes remain a practical challenge. We present scanCT (single-cell analysis of Clinical Tree), a tree-based framework that identifies groups of genomic features associated with distinct disease phenotypes in a highly interpretable manner. scanCT uses an unbiased, model-based variable-selection procedure for data-driven split selection, which is important for handling the diverse distributional properties of single-cell data across modalities. The tree architecture captures feature interaction effects, and the association modeling enables adjustment for confounding factors. We apply scanCT to longitudinal single-cell multi-omics COVID-19 datasets spanning diverse clinical outcomes and multiple time points per patient. scanCT identifies phenotype-specific gene and protein markers while accounting for age and sex, and it reveals interpretable synergistic marker combinations that help explain differences in patient clinical phenotypes.

bioinformatics↗

Lifespan Trajectories of Asymmetry in White Matter Tracts

Asymmetry in white matter is believed to give rise to the brains capacity for specialized processing and is involved in the lateralization of various cognitive processes, such as language and visuo-spatial reasoning. Although studies of white matter asymmetry have been previously documented, they have often been constrained by limited age ranges, sample sizes, or the scope of the tracts and structural features examined. While normative lifespan charts for brain structures are emerging, comprehensive charts detailing white matter asymmetries across numerous pathways and diverse structural measures have been notably absent. This study addresses this gap by leveraging a large-scale dataset of 35,120 typically developing and aging individuals, ranging from 0 to 100 years of age, from 50 primary neuroimaging studies. We generated comprehensive lifespan trajectories for 30 lateralized association and projection white matter tracts, examining 6 distinct microstructural and macrostructural features of these pathways. Our findings reveal that: (1) asymmetries are widespread across the brains white matter and are present in all 30 pathways; (2) for a given pathway, the degree and direction of asymmetry differ between features of tissue microstructure and pathway macrostructure; (3) asymmetries vary across and within pathway types (association and projection tracts); and (4) these asymmetries are not static, following unique trajectories across the lifespan, with distinct changes during development, and a general trend of becoming more asymmetric with increasing age (particularly in later adulthood) across pathways. This study represents the most extensive characterization of white matter asymmetry across the lifespan to date, charting how lateralization patterns emerge, mature, and change throughout life. It provides a foundational resource for understanding the principles of white matter organization from early to late life, its relation to functional specialization and inter-individual variability, and offers a key reference for interpreting deviations during healthy development and aging as well as those associated with clinical populations.

neuroscience↗

Programmable Aptamer-Embedded Circular RNAs for Targeted Antigen-Presenting Cells Immunotherapy

The targeted delivery of mRNA to specific cell types in vivo remains a major unmet need in mRNA-based therapeutics. Conventional strategies rely on nanocarriers engineered with various modifications. However, these exogenous materials could cause adverse reactions, and their complex manufacturing processes often hinder clinical application. By leveraging the innate programmability of RNA sequences, we herein report a carrier-free, scalable, and programmable aptamer-embedded circular RNAs (Apt-circRNAs) design that confers targeting capability through the strategic incorporation of different aptamers at varying densities, while retaining circular RNA stability and protein production capability. Experimental results show that antigen-loaded Apt-circRNAs enable targeted delivery to antigen-presenting cells (APCs), drive endogenous antigen expression, activate antigen-specific T cells, and elicit potent immune responses that mediate clearance of both early-and late-stage tumors in mouse models. In humanized models of colorectal cancer, the combination of Apt-circRNA and PD-1 blockade produced synergistic antitumor effects and significantly reshaped the tumor microenvironment. In a first-in-human (FIH) clinical trial, Apt-circRNA vaccine encoding KRAS G12D/G12V neoantigens exhibited a favorable safety profile and induced robust immune activation, T cell mobilization, and neoantigen-specific immune responses. With this study, we have established a new paradigm in carrier-free, APC-targeted RNA vaccine design, offering a safe and effective platform for next-generation cancer immunotherapy.

bioengineering↗