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Li, H.

Publications and source records attributed to Li, H..

At least 145 records · Page 8Linked to original sources

An oncolytic adenovirus armed with anticancer prodrug-activating enzyme offers enhanced tumor killing and antitumor immunity.

Oncolytic viruses are most commonly administered via intratumoral injection; however, their clinical efficacy in achieving tumor eradication remains limited by several challenges, including insufficient penetration into all tumor cells and the inability to elicit robust systemic antitumor immune responses capable of eliminating metastatic microtumors. Here, we report an oncolytic adenovirus, OAd-2B6, with an engineered adenoviral E1 region for tumor selectivity and carrying the prodrug- activating enzyme cytochrome P450 2B6 (CYP2B6) to activate the anticancer prodrug cyclophosphamide (Cytoxan, CTX). OAd-2B6 alone induced dose-dependent tumor cell killing across multiple human tumor cell lines and exhibited strong synergistic antitumor effects when combined with CTX. Importantly, OAd-2B6-mediated local activation of CTX resulted in a potent bystander killing effect that eliminated tumor cells not directly infected by the virus. In a H1299 lung cancer xenograft nude mouse model, intratumoral injection of OAd-2B6 combined with CTX significantly inhibited tumor growth and even achieved complete tumor regression, with markedly superior efficacy compared with monotherapy. In immunocompetent mice bearing 4T1 breast cancer xenografts, OAd-2B6 alone inhibited tumor growth and was accompanied by upregulation of IFN-{gamma} and GzmB expression in the tumor-infiltrated T cells. CTX combination therapy further enhances this anti-tumor immune response, promoting the activation of T cells to suppress non-injected tumors at a distal site. Collectively, this study demonstrates that OAd-2B6 exerts potent antitumor effects through multiple mechanisms, including direct oncolysis, intratumoral prodrug activation leading to bystander killing, and enhancement of systemic antitumor immunity. These findings provide a promising strategy for improving the therapeutic efficacy of oncolytic therapy.

cancer biology↗

Decoding Immune Reconstitution Failure in People Living with HIV through Single-cell Genomics

Immune non-responders (INRs), a subset of people living with HIV (PLWH), fail to achieve full immune reconstitution and remain at increased risk of morbidity, mortality, and non-AIDS-related illnesses. As the mechanisms underlying this impaired immune recovery remain poorly understood, we performed single-cell multi-omics profiling on peripheral blood mononuclear cells from 43 INRs, 47 immune responders and 53 healthy donors. Our dataset comprises 2,744,009 transcriptomes and 1,226,658 chromatin-accessibility profiles across 58 identified immune cell types. INRs exhibited markedly elevated inflammatory signaling, increased apoptotic activity, and dysregulation of immune-activating ligand-receptor interactions. Additionally, we identified 2,996 interaction cis-eGenes and 5,938 cis-caPeaks, and validated key cell type-specific cis-xQTL effects associated with immune reconstitution failure. Furthermore, we identified 3,551 sc-eQTLs and 872 cell-state interaction eQTLs (ieQTLs) in CD4+ T cells. A genotype-specific upregulation of OAS3 in INRs, likely regulated by STAT1, was identified based on these results. We developed scPRISM (single cell Predictive Reconstitution Immune Status Model), a multi-modal framework that integrates scRNA-seq and scATAC-seq data to perform the dual tasks of differentiating disease states and predicting gene expression from chromatin accessibility, thereby deciphering the cell type-specific cis-regulatory basis of the disease. Our study delineates the transcriptional and epigenomic landscape of immune dysregulation in INRs and provides new genetic insights into HIV-associated immune reconstitution failure. These findings offer a foundation for developing biomarkers and precision therapies to restore immune function in PLWH.

genetics↗

Force-regulated catch bonds and fusion peptide exposure drive coronavirus entry

Coronaviruses invade human cells within dynamic mechanical environments through endocytosis and membrane fusion, both mediated by the class I fusion protein spike. In SARS-CoV and SARS-CoV-2, the spike engages the human ACE2 receptor through a catch bond--an interaction whose lifetime increases under tensile force. Concurrently, mechanical pulling facilitates disruption of the S1/S2 subunits of spike, a critical step for membrane fusion. To elucidate how mechanical cues coordinate these processes, we developed a unified elastic-stochastic model that integrates theoretical analysis and computational simulations to trace viral entry. Our results identify the force-regulated catch bond between spike and ACE2 as a key determinant of successful invasion. This catch bond not only enhances receptor-mediated endocytosis but also increases the probability of S1/S2 disengagement, thereby promoting membrane fusion. Importantly, under conditions of strong catch bonding, the force-accelerated separation of S1 and S2 fine-tunes the balance between entry pathways. These findings uncover a potential mechanobiological mechanism that mediates viral cell entry by coupling receptor binding strength with spike disassembly under force. By characterizing these mechanical regulations, this work facilitates the assessment of emerging viral threats and inspires the design of drug delivery systems that leverage catch-bond kinetics for enhanced targeting.

biophysics↗

Widespread use of invalid statistical tests in biomedical machine learning

Cross-validation is routinely used to compare performance in biomedical artificial intelligence. Standard tests ignore correlation across cross-validation folds, inflating false-positive rates. In a PRISMA-guided meta-analysis of 184 studies (impact factor [≥] 15) across 30 biomedical fields, 97% use invalid tests. Among studies with abstract-level claims supported by invalid tests, 59% rely on a spurious comparison: one that loses significance after correcting for this correlation. On average, regaining significance requires a 43% larger effect. Extending these findings to the broader literature, we estimate that spurious comparisons occur in nearly two in three studies and support abstract-level claims in nearly one in three studies. Simulations confirm false-positive rates paradoxically approach 100% when cross-validation is repeated to improve stability. We introduce SHARP, a redesign of cross-validation, which best balances false-positive control and power among 13 benchmarked tests. These results reveal widespread fragility in biomedical artificial intelligence and offer a practical route to valid comparisons.

bioinformatics↗

From 3D Time-of-Flight Angiography to Accelerated 4D Arterial Spin Labeling Angiography: A Fast Few-Shot Transfer Learning Approach

PurposeTo develop a data-efficient deep learning framework for rapid reconstruction of highly accelerated 4D arterial spin labeling (ASL) magnetic resonance angiography (MRA) with robust generalization using extremely limited acquired data, addressing the challenges of prolonged acquisition and reconstruction time. MethodsA simulation-driven, few-shot transfer learning approach was adopted by leveraging publicly available 3D time-of-flight (TOF)-MRA data to generate realistic multi-coil complex-valued pseudo-ASL k-space datasets for large-scale pre-training. A 3D unrolled reconstruction network was trained on this simulated data using a histogram-weighted loss and subsequently extended to 4D using lightweight temporal fusion modules. Fine-tuning was performed using only two experimentally acquired 4D ASL-MRA datasets. The method was evaluated on retrospectively and prospectively undersampled Cartesian 4D ASL-MRA data acquired at 3T and compared with compressed sensing (CS) and locally low-rank (LLR) reconstructions. ResultsThe proposed method achieved superior reconstruction quality compared with CS and LLR, with improved vessel depiction, particularly in distal branches, and enhanced temporal fidelity. Quantitative evaluation demonstrated higher vessel-masked peak signal-to-noise ratio and structural similarity index measure, along with increased error entropy, indicating reduced noise and structured artifacts. The initial pre-trained model already outperformed conventional methods, while additional 4D fine-tuning further improved performance. Robust reconstruction was demonstrated in prospectively undersampled data and multi-slab acquisitions, enabling large-coverage, time-resolved angiography within clinically feasible scan times (4-6 min). ConclusionsSimulation-driven pre-training combined with few-shot fine-tuning enables accurate and rapid reconstruction of highly accelerated 4D ASL-MRA in data-limited settings. The proposed framework provides a practical pathway toward clinically feasible, non-contrast dynamic cerebrovascular imaging.

neuroscience↗

Extending structural surfaceomics to identify aberrant conformations of tumor surface proteins as potential immunotherapy targets

The complement of tumor cell surface proteins, or "surfaceome", is a rich source of potential immunotherapy targets. To move beyond expression-based target discovery, we previously described "structural surfaceomics," combining crosslinking mass spectrometry (XL-MS) with surface protein biotinylation to identify conformation-selective targets. In our prior work, we applied this method to a single model of acute myeloid leukemia (AML), identifying active integrin beta-2 as a promising target. Here, we expand structural surfaceomics to identify additional immunotherapy targets and surface protein biology across additional models of AML, multiple myeloma, and prostate cancer, as well as donor peripheral blood mononuclear cells. Utilizing these models and different chemical crosslinkers, we compile an extensive database of 5,209 crosslinks. We characterize both shared and unique crosslink-based features, identifying 1,612 disease model-specific crosslinks, including 212 potentially defining tumor-specific conformations based on distance constraint violations relative to AlphaFold predictions. We further implement a suite of emerging modeling tools to predict tumor-specific protein structures. We probe crosslinking patterns suggesting multiple myeloma-specific CD48 and AML-specific integrin 1/{beta}4 heterodimer conformations. This work establishes a resource for cancer structural biology by implementation of structural surfaceomics. Our findings also point toward more realistic protein design models, potentially enabling systematic detection of targetable cancer-specific epitopes for next-generation immunotherapies.

cancer biology↗

RT-nested and interfering-Primer PCR reveal prevalent isoform-specific A-to-I RNA editing in neuronal genes

BackgroundMetazoan adenosine-to-inosine (A-to-I) mRNA editing temporospatially diversifies the neuronal transcriptome and proteome. The limited read length from next-generation sequencing (NGS) constrains the quantification of the potentially differential editing levels across different splicing isoforms, restricting our understanding of the extent to which RNA editing contributes to molecular diversity and its interplay with splicing. MethodsWe employed reverse transcription nested PCR (RT-nPCR) and developed a novel interfering-Primer PCR (iPrimer PCR) technique to distinguish different transcripts of any gene. We selected multiple essential genes exhibiting RNA editing in coding sequences (CDSs) or untranslated regions (UTRs) for isoform-specific amplification and Sanger sequencing. ResultsNine different Adar isoforms together with pre-mRNA had distinct editing levels at the S>G auto-recoding site, which was predicted to have isoform-specific effects on catalytic activities. Although pre-mRNA editing might exert isoform-dependent promotion/suppression of splicing, closely located editing sites, such as those in neuronal genes qvr and stj, still exhibited high correlation in editing levels due to co-editing. iPrimer strategy further discovered differential recoding levels between the long/short 3UTR isoforms of gene jef. ConclusionsWe provide the first comprehensive solution for isoform-specific PCR amplification of any gene, enabling quantification of RNA editing level of different isoforms. Our results offer insights into how RNA editing interplays with splicing, and highlight its complicated role in expanding molecular diversity. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=79 SRC="FIGDIR/small/725286v1_ufig1.gif" ALT="Figure 1"> View larger version (17K): org.highwire.dtl.DTLVardef@3c4e61org.highwire.dtl.DTLVardef@13def88org.highwire.dtl.DTLVardef@138fa91org.highwire.dtl.DTLVardef@1ca7460_HPS_FORMAT_FIGEXP M_FIG C_FIG We developed isoform-specific PCR followed by Sanger sequencing, and achieved the quantification of differential RNA editing levels in different transcripts of a gene.

molecular biology↗

Tumor-derived mitochondria enhance CD8+ T cell cytotoxicity through SPHK2-dependent S1P signaling

Intercellular organelle exchange is increasingly recognized as a feature of the tumor microenvironment, but whether tumor-derived mitochondria functionally shape anti-tumor T cell immunity remains unclear. Here we show that tumor-infiltrating CD8+ T cells acquire functional mitochondria from tumor cells through a contact-dependent, TCR-independent mechanism requiring the mitochondrial trafficking machinery Trak1-Miro1. Transferred tumor mitochondria enhanced CD8+ T cell effector activity, increasing cytotoxic molecule expression and tumor-cell killing. Mechanistically, tumor-derived mitochondria carried sphingosine-1-phosphate (S1P), which engaged S1PR1 signaling in recipient T cells. Tumor-specific deletion of Sphk2 diminished mitochondrial transfer-associated T cell activation, impaired CD8+ T cell effector function, and accelerated tumor progression in vivo. These findings reveal tumor-to-T cell mitochondrial transfer as an unexpected immunostimulatory circuit in the TME and identify mitochondrial SPHK2-S1P signaling as a regulator of CD8+ T cell anti-tumor function.

cell biology↗

Microbiome-mediated lauric acid turnover contributes to colonization resistance against Ralstonia in the tomato rhizosphere

Host-associated lipids shape plant-microbiome interactions, but their microbiome-mediated turnover and role in pathogen exclusion are not fully understood. In tomato, lauric acid (C12:0) occurs across root-associated compartments, and its abundance at the root-soil interface is linked to soil-dependent differences in rhizosphere community composition and Ralstonia solanacearum colonization. Lauric acid promotes Ralstonia motility and virulence in vitro while inhibiting some beneficial lauric-acid-sensitive taxa, especially Gram-positive antagonists. In disease-suppressive soils, rhizosphere communities enriched in lauric-acid-degrading taxa are associated with lower local lauric acid levels and reduced pathogen colonization, suggesting community-dependent buffering of the rhizosphere lauric acid pool alongside other protective microbiome functions. Soil perturbation, microbiome transplantation, gnotobiotic SynCom reconstruction, and isotope tracing provide convergent evidence that microbiome-mediated lauric acid turnover contributes to colonization resistance and helps explain how rhizosphere lipid chemistry influences pathogen invasion outcomes in tomato, revealing an ecologically grounded protective mechanism for pathogen management.

microbiology↗

A compact Druantia defense clears phage infections via single-stranded DNA recognition and directional duplex unwinding

Bacteria encode diverse anti-phage defense systems triggered by invader-specific molecular cues. Here, we report that the compact type III-A Druantia system recognizes exposed single-stranded DNA to drive phage clearance. Using representative systems from Escherichia coli, we show that the two encoded proteins, DruE and DruH, together clear restriction-sensitive or recombination-prone phages without affecting cell growth or viability. DruE dimerizes and engages DNA at exposed single-stranded regions to unwind DNA with 3'-to-5' directionality, resorting to unique molecular lock, wedge, and clamp elements that aid strand separation and processive translocation. DruH is a monomer in isolation and indirectly interacts with DruE and other host proteins under uninfected conditions, with an infection resulting in the dissociation of the complex. Taken together, our results reveal that exposed single-stranded DNA can trigger bacterial immunity through the directional helicase activity of type III-A Druantia. HighlightsO_LIThe E. coli Druantia III-A defense, comprising DruE and DruH, clears infecting phages C_LIO_LIDruE dimers bind exposed single-stranded DNA and unwind the upstream DNA duplex C_LIO_LI3'-to-5' DNA unwinding is aided by molecular lock, wedge, and clamp elements C_LIO_LIDruE interacts with DruH and host proteins, which are displaced upon infection C_LI

microbiology↗

Reversible in vivo regulation of drug metabolizing enzyme CYP1A2 activity through a dTAG knock-in strategy

Drug-metabolizing enzymes determine therapeutic exposure, efficacy and toxicity, but defining their isoform-specific functions in vivo remains challenging. Cytochrome P450 enzymes (P450s) are central to drug metabolism and pharmacokinetics (DMPK) and mediate the phase I metabolism of [~]75% of all marketed drugs. However, conventional knockout models can induce develop-mental and compensatory adaptations, and selective inhibitors are unavailable for many P450 isoforms. Here, we report the use of an inducible chemical-genetic platform for acute and specific degradation of the endogenous P450 enzyme Cyp1a2 in mice. Using CRISPR-Cas9-mediated knock-in editing, we introduced an FKBP12F36V degron into the endogenous Cyp1a2 locus to generate Cyp1a2dTAG mice. Treatment with the dTAG degrader dTAG-13 recruited an E3 ubiquitin ligase to CYP1A2dTAG, resulting in rapid and reversible proteasomal depletion of CYP1A2dTAG in vivo. Temporally controlled CYP1A2dTAG loss altered caffeine pharmacokinetics as expected, validating this model as a functional tool for DMPK studies. By enabling reversible suppression of drug-metabolizing enzymes without permanent deletion or chronic inhibitor exposure, this work establishes targeted protein degradation as a broadly adaptable strategy for studying drug metabolism in vivo and provides a foundation for extending inducible DMPK control to other P450s, conjugating enzymes and transporters.

pharmacology and toxicology↗

NFIC-mediated CaSR endocytosis defines a hyperactive TOMM20highCHGAhigh oxyphil cell state as a pathological driver of autonomous secondary hyperparathyroidism

Secondary hyperparathyroidism (SHPT) is a debilitating complication of chronic kidney disease. Its clinical management is frequently compromised by calcimimetic resistance, a refractory state primarily driven by the progressive downregulation of the membrane calcium-sensing receptor (CaSR). Despite the centrality of CaSR as a therapeutic target, the mechanisms governing its aberrant expression and membrane localization remain incompletely elucidated. Here, we generated a single-cell transcriptomic atlas of human parathyroid tissues from SHPT and primary hyperparathyroidism (PHPT) patients, uncovering a unique stromal-immune niche that is specifically induced by uremic stress in SHPT. Our data also observed a striking dissociation between CaSR mRNA and its abundance as a membrane protein in SHPT tissues. Pseudotime trajectory analysis showed a progressive decline in CaSR pathway activity and a concomitant increase in endo-lysosomal activity along the trajectory, terminating in pathological oxyphil cells as the endpoint of chief cell differentiation in SHPT. Mechanistically, Nuclear Factor I C (NFIC) transcriptionally activated clathrin light chain B (CLTB) and Ras-related protein Rab7a (RAB7A) to trigger clathrin-mediated endocytosis and lysosomal degradation of CaSR, thus reducing its membrane abundance. This degradative program was further validated by multiplex immunofluorescence in TOMM20highCHGAhigh pathological oxyphil cells in human SHPT tissues. To translate these mechanistic findings into a clinically actionable strategy, we repurposed the clinically approved lysosomal inhibitor hydroxychloroquine (HCQ) to block this CaSR degradation pathway. In patient-derived xenograft (PDX) mouse models, co-administration of HCQ and cinacalcet acted synergistically to restore membrane CaSR expression, normalize serum PTH and calcium levels and suppress parathyroid tumor growth more effectively than monotherapies. Collectively, our single-cell-guided study identifies an NFIC-driven endo-lysosomal program as a previously unrecognized mechanism underlying CaSR downregulation and calcimimetic resistance in SHPT, and establishes HCQ repurposing as a clinically tractable therapeutic strategy for patients with refractory SHPT.

cell biology↗

Intrinsic regulation of intestinal stem cell fate and homeostasis by Tet

How developmental progenitors navigate divergent trajectories to either establish adult stem cell pools or undergo terminal differentiation remains a fundamental gap in stem cell biology. Here, we identify the well conserved Tet protein as an essential transcriptional regulator of intestinal stem cell (ISC) establishment. Developmental Tet depletion causes region-specific ISC loss and compromises adult lifespan, while adult-specific loss drives progressive stem cell exhaustion. Overexpression of Tet leads to ISC expansion in both developing and adult guts. Utilizing a comprehensive single-nucleus transcriptomic atlas spanning gut development, we demonstrate that Tet stabilizes progenitor identity by maintaining epithelial integrity, niche signaling, and fate maintenance. By defining this developmental trajectory, we reveal Tet as a critical factor that drives proper ISC maturation and maintains long-term adult epithelial homeostasis.

developmental biology↗

Evolution of Protein Regulation in the Vertebrate Glucose Sensor

Protein regulation is essential for cellular function and mis-regulation commonly causes disease. Despite this fact, we know little about how new regulatory strategies first emerge and how they evolve to act in concert to control complex physiological processes. Glucokinase (GCK), the bodys glucose sensor, lies at the heart of vertebrate glucose homeostasis and its activity is tightly controlled by multiple regulatory mechanisms. In the pancreas and liver, GCK is regulated by a unique form of monomeric allostery originating from the unliganded enzymes conformational dynamics. In the liver, GCK and GKRP form an inhibitory protein-protein interaction that sequesters GCK within the hepatocyte nucleus. Using a vertical, evolutionary approach, we resurrected extinct GCKs and GKRPs along correlated evolutionary trajectories. Using enzyme kinetics, limited proteolysis, hydrogen-deuterium exchange, high resolution NMR, and X-ray crystallography we determined the historical and molecular origins of protein regulation. Prior to the emergence of jawed vertebrates, a non-regulated GCK ancestor underwent a conformational expansion leading to monomeric allostery. This novel conformation includes an intrinsically disordered substrate binding loop. Paradoxically, the emergence of disorder did not require sequence change in the loop. The new GCK conformation also exposed a hydrophobic cleft. In the jawed vertebrate GKRP ancestor, a de novo loop insertion enabled exaptation of the pre-existing hydrophobic patch in GCK. Our results demonstrate how multiple, distinct regulatory strategies can arise at a central homeostatic control point through evolutionary addition of novel conformations. Additionally, our results provide a general mechanism for the emergence of heteromeric protein-protein interactions. Significance StatementGlucose homeostasis was a key innovation in vertebrate evolution. Here, we uncover the evolutionary basis of regulation in two key homeostatic proteins, glucokinase (GCK) and glucokinase regulatory protein (GKRP). We find that the unique cooperativity of vertebrate GCK resulted from an expansion of this enzymes conformational landscape. This expansion included sampling a new state and the emergence of intrinsic disorder, which did not require substitutions in the disordered region itself. We also discover that the GCK-GKRP interaction emerged when a pre-existing hydrophobic surface -- a structural spandrel resulting from prior conformational expansion -- was co-opted by loop insertion in GKRP, facilitating a new, inhibitory heteromeric interaction. Our results demonstrate how multiple, mechanistically distinct regulatory strategies arise from an ability to sample new protein conformations.

biochemistry↗

In vivo elastography of the human retina using light-evoked intrinsic actuation

The biomechanical properties of the retina govern its function, structural integrity, and susceptibility to disease, yet remain difficult to measure in vivo due to the lack of safe, spatially localized mechanical actuation. Here, we introduce a framework for probing retinal biomechanics in the living human eye by leveraging intrinsic optical actuation driven by phototransduction. Using phase-resolved optical coherence tomography with a local phase-referencing approach, we resolved signed, nanometer-scale displacements of the major outer retinal interfaces evoked by light. The resulting deformation field, originating in the photoreceptor outer segment, was distributed across retinal compartments in an eccentricity-dependent manner, with efficient axial transfer in the fovea and attenuated propagation in the parafovea. A hybrid analytical and finite-element framework was developed that retrieved the biomechanical properties of the retinal compartments based on their coordinated deformation and the anatomical variation in retinal structure versus eccentricity. In retinitis pigmentosa, the paradigm enabled the detection of light-evoked deformation in the transition zone despite the loss of native lamination, enabling a functional readout of the vulnerable photoreceptors at the leading edge of degeneration. Together, these results establish intrinsic optical stimulation as a basis for in vivo retinal elastography and enable the non-invasive, quantitative imaging of retinal biomechanics and function in the living human retina.

biophysics↗

Computational modeling of pro-inflammatory cytokine-enhanced blood coagulation

The interplay between inflammation and coagulation is a central driver of thrombotic risk across various diseases. While mathematical models of blood coagulation are well established, there remains a critical gap in quantitative frameworks that capture inflammation-induced hypercoagulability. In this study, we develop a mathematical model that explicitly simulates the interaction between pro-inflammatory cytokines and the coagulation cascade. The model incorporates key mechanisms, including: (i) upregulation of tissue factor (TF) by IL-1{beta}, IL-6, and TNF-; (ii) suppression of natural anticoagulants, namely antithrombin III (ATIII) and tissue factor pathway inhibitor (TFPI), by IL-6 and TNF-; and (iii) feedback amplification of proinflammatory cytokines by thrombin. By encoding the bidirectional feedback between inflammatory and coagulation pathways, the model captures essential features of inflammation-driven hypercoagulability and enables systematic quantification of how variability in inflammatory extent and duration results in heterogeneous thrombin generation (TG) dynamics. To evaluate its effectiveness, we integrate the model with TG assays and apply it to virtual patient cohorts representing four clinically distinct conditions: COVID-19, sickle cell disease (SCD), type 2 diabetes mellitus (T2DM) and Hemophilia A. Model simulations predict that disease-specific inflammatory environments induce distinct shifts in TG dynamics. In COVID-19 and T2DM, elevated cytokine levels lead to shortened lag times and increased thrombin peak, whereas in SCD, shortened lag times are accompanied by a reduced thrombin peak. These effects are strongly modulated by both cytokine concentration and duration of exposure. These results demonstrate that the proposed computational model augments conventional TG assays by mechanistically linking inflammatory signaling to disease-specific coagulation responses. Collectively, the proposed computational framework extends conventional TG assays by considering the interplay between inflammation and coagulation, thereby providing a potential tool for predicting disease progression and identifying disease-specific therapeutic targets to advance personalized management strategies in thrombo-inflammatory disorders.

biochemistry↗

NLRP3 inflammasome-related microglial pyroptosis in EcoHIV infected mice

HIV-associated neurocognitive disorders (HAND) have become a major clinical concern, particularly among the aging HIV-1-seropositive population, which is generally characterized by persistent viral reservoirs and a lower level of chronic inflammation. NLRP3 inflammasome activation exhibits its unique role in the progression of many chronic inflammatory diseases. Furthermore, pyroptosis, an inflammatory form of programmed cell death, has been implicated in numerous neurological diseases. However, the mechanisms linking EcoHIV infection, microglial pyroptosis, and NLRP3 inflammasome activation remain incompletely understood. In this study, EcoHIV was retro-orbitally injected into C57BL/6J wild-type mice and analyzed at 14-, 30-, 60-, and 90-days post-infection to establish a NeuroHIV model. Additionally, in vitro, BV2 microglial cell line was infected with EcoHIV and treated with MCC950, an inhibitor of the NLRP3 inflammasome, for three days. Pyroptosis marker GSDMD, NLRP3 inflammasome components, Caspase-1 (a marker of inflammasome activation), HLA-DR (an immune activation marker), Programmed-death 1 (PD-1, an immune checkpoint molecule), and Ki67 (a cellular proliferation marker) were assessed by immunofluorescence staining. Results showed that EcoHIV-infected mice showed a peak in NLRP3 expression at 14 days post-infection, compared with controls, followed by a modest decline at 30 days, while GSDMD expression increased progressively across 14 and 30 days. These findings demonstrate dynamic changes in microglial pyroptosis and NLRP3 inflammasome activation over the course of EcoHIV infection. In vitro, EcoHIV-infected BV2 cells exhibited significantly increased EcoHIV-eGFP fluorescence compared with controls, confirming the utility of BV2 cells as an in vitro model of microglial EcoHIV infection. Expression levels of GSDMD and NLRP3 were elevated following infection, indicating enhanced pyroptosis and neuroinflammation. Treatment with MCC950 significantly reduced the expression of GSDMD, NLRP3, HLA-DR, PD-1, and Ki67, suggesting that inhibition of NLRP3 inflammasome activity suppresses both pyroptosis and microglial activation and proliferation. Together, elucidating the interplay between microglial pyroptosis and NLRP3 inflammasome activation may provide new insights into the pathogenesis and potential therapeutic strategies for NeuroHIV in the aging HIV-1-seropositive population.

neuroscience↗

Decoding the BRCA2 reversion principles underlying PARP inhibitor resistance

Reversion mutations that restore BRCA2 function represent a major mechanism of resistance to poly(ADP-ribose) polymerase inhibitors (PARPi) in BRCA2-mutant cancers. Predicting these events could inform treatment strategies, identify patients at increased risk of acquiring PARPi resistance, and improve interpretation of secondary variants. Here, we use an isogenic cell system and CRISPR editing to define the principles governing BRCA2 reversion. We show that local sequence context dictates the spectrum of reversions, whereas domain architecture determines which events confer PARPi resistance. We characterize two routes of reversion that operate both within and across exons: DNA-level reading-frame restoration and transcript-level rescue via alternative splicing. Lastly, we identify distinct exon 11 reversion mechanisms, including large genomic deletions and recurrent splice isoforms predicted to remove all eight BRC repeats. These findings define a predictive code for BRCA2 reversion and PARPi resistance.

cancer biology↗