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Cao, X.

Publications and source records attributed to Cao, X..

At least 55 records · Page 3Linked to original sources

Reconciling Cooperativity Definition in PROTACs and Molecular Glues: Thermodynamic Dissection into PPI and Ligand Entropic Contributions

Douglass Cooperativity and Ciullis Cooperativity in induced-proximity systems, remains controversial with paradoxes such as path-dependent metrics and apparent universal negative Cooperativity. We noticed that in "partial-embedded" model, a substantial portion of giant ligand remains exposed outside and does not engage with the host proteins force field. It incurs an entropic cost due to the restriction of translational/rotational degrees of freedom. This large, mass-dependent unfavorable ligand entropy penalty normally shifts binding affinity to 104[~]108-fold. ITC thermodynamic cycles analysis confirmed the dramatic entropy loss among reaction pair. This reconciles the conflicting Cooperativity definitions, yielding true path-independent positive PPI Cooperativity from observed entropy loss subtracting ligand entropy penalty. ITC data showed rigid linkers appear superior to flexible linkers with respect to both oral bioavailability and safety profile in PROTAC design. "ligand entropy barrier wall/Cooperativity ladder" pair is not only impact induced-proximity systems but also constitute the physical basis for all biosystems.

biochemistry↗

Cell type-specific proximity labeling of organ secretomes reveals energy balance-dependent proteomic remodeling.

Intercellular communication is critical for maintaining organismal metabolic homeostasis. Here, we present a new method enabling temporally controlled, cell type-specific labeling of secreted and membrane proteins in key metabolic tissues. The method employs a genetically encoded proximity-labeling strategy by targeting a Cre-dependent TurboID ligase to the endoplasmic reticulum (ER) in ES cell-derived mice. Expression of TurboID in liver, adipose tissue, and spleen enabled the characterization of organ-specific ER proteomes at baseline and in response to fasting, inflammation, and dietary obesity, revealing tissue-and perturbation-specific changes and augmenting our understanding of how the proteomes of individual tissues change to regulate systemic energy balance. This comprehensive resource represents an important advance toward understanding both how cell-to-cell communication changes in response to energy homeostasis and how it contributes to these alterations. This method is broadly applicable and provides a means for identifying biomarkers and therapeutic targets across a wide range of tissues.

physiology↗

Cross-species insights into placental evolution and diseases at the single-cell resolution

The placenta is a highly specialized organ in mammals, mediating the exchange of nutrients, gases, and waste between the mother and the fetus while orchestrating intricate immunological interactions to sustain a successful pregnancy. Despite its essential roles, the molecular evolution underlying the diversity of placentas across mammalian species remains largely elusive. Here, we constructed a comprehensive mammalian placental single-cell transcriptomic atlas from approximately 300,000 cells spanning ten species that could well represent the four primary placental types: (discoid, cotyledonary, diffuse, and zonary. Our cross-species analysis highlights trophoblast lineages as key drivers for placental evolution. By reconstructing differentiation trajectories, we elucidate the gene expression dynamics and regulatory networks shaping trophoblast development across diverse placental architectures. Besides, we propose that the association of human trophoblasts with conditions such as pre-eclampsia and miscarriage arises from their unique gene expression profile, which distinguishes them from trophoblasts of other species. The functional experiments further demonstrate that TGIF1 acts as an upstream regulator of key functional genes in extravillous trophoblast cells, modulating their growth, invasion, and migration. Additionally, TGIF1, along with its target genes, such as ADAM12, WNT3A, and ZNF831, is associated with preeclampsia and pregnancy loss. Collectively, these findings provide a high-resolution framework to understand the molecular evolution of the placenta and its role in reproductive success and diseases.

evolutionary biology↗

Ectopic engraftment of nociceptive neurons derived from hPSCs for pain relief and joint homeostasis

Chronic pain arises from the interplay of inflammatory signals that activate and sensitize nociceptors within injured tissues. Most analgesics fail clinically due to their mono-targeted mechanisms. Here, we apply human pluripotent stem cell-derived nociceptive neurons (hPSC-NNs) as therapeutic agents for osteoarthritis, targeting both pain and joint degeneration. We generated sensory neurons from hPSCs and identified CD200 as a nociceptor marker. Transcriptomic and functional profiling revealed that CD200highhPSC-NNs closely resemble human nociceptors, expressing pain-relevant receptors and ion channels. Strikingly, ectopic transplantation of CD200highhPSC-NNs into the knee joint of osteoarthritic mice reduced pain and promoted bone and cartilage repair, whereas CD200low cells exhibited no benefit. Mechanistically, human and mouse proteomics suggest that CD200highhPSC-NNs act as decoys by sequestering inflammatory ligands while secreting reparative factors in joint tissues. These findings uncover a fundamental role of nociceptors in tissue repair, providing a multi-targeted, disease-modifying strategy for OA and chronic pain. GRAPHIC ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=200 SRC="FIGDIR/small/694733v1_ufig1.gif" ALT="Figure 1"> View larger version (70K): org.highwire.dtl.DTLVardef@15f0948org.highwire.dtl.DTLVardef@5a59bforg.highwire.dtl.DTLVardef@1ba4439org.highwire.dtl.DTLVardef@1d518d1_HPS_FORMAT_FIGEXP M_FIG C_FIG HIGHLIGHTSO_LIhPSC-derived nociceptors (hPSC-NNs) as Decoy Engraftment for Cellular Interception and Repair (DECIR) when transplanted into the knee joint, extending beyond conventional regenerative strategies C_LIO_LICD200 serves as a clinically actionable surface marker for the purification of hPSC-NNs C_LIO_LIEctopic grafting of CD200high hPSC-NNs delivers dual benefits, alleviating pain and modulating the neuro-immune environment within joint tissues C_LIO_LIProteomic analyses reveal that CD200highhPSC-NNs sequester inflammatory mediators and secrete reparative factors to support joint homeostasis C_LI

neuroscience↗

Adapting Epigenetic Clocks for Cell-Free DNA High-Throughput Sequencing Data

Background.Circulating cell-free DNA (cfDNA or ccfDNA) methylation sequencing holds promise for developing epigenetic aging clocks in minimally invasive aging assessment applications. However, current clocks--primarily trained on array-based data--do not readily generalize to methylation profiles of cfDNA, due to stochasticity and uncertainty arising from the limited input amounts of cfDNA and technical characteristics of high-throughput sequencing (HTS) platform. Due to lack of training to correct this uncertainty, direct application of legacy clocks to HTS data will inevitably produce unreliable estimates, introduce predictive discordance and undermine the trustworthiness of epigenetic biomarkers. Despite this urgent challenge, a systematic, model-agnostic framework for adapting existing epigenetic clocks to HTS-based cfDNA data remains lacking. Methods.Here, we generated a dedicated benchmark dataset comprising paired cfDNA and genomic DNA (gDNA), which was replicated and profiled across two methylation arrays and two targeted HTS platforms. We evaluated 53 epigenetic clocks for CpG coverage, reproducibility, cross-platform consistency, and age prediction accuracy. Further, we systematically explored and tested multiple adaptation strategies including depth filtering, beta-value imputation, and transfer learning via model distillation aiming at improving performance and clinical concordance of legacy epigenetic clocks on cfDNA HTS datasets. Results.Our results show that inherent technical noise of HTS platforms compromises diagnostic precision, presenting as a significant burden for applying legacy clocks on cfDNA HTS data. However, this technical limitation can be systematically neutralized. By enforcing stringent sequencing depth protocols ([≥]10x ideally 20x), employing robust algorithmic stabilization (L2-heavy clocks and imputation) and transfer learning, we can effectively isolate genuine physiological aging signals from technical artifacts. Ultimately, an adaptation pipeline incorporating all these methods effectively improved age prediction accuracy and, closed the gap between epigenetically induced aging status and clinically assessed realities. Besides, the pipeline demonstrated improved diagnostic sensitivity for neurodegenerative conditions such as amyotrophic lateral sclerosis, establishing a reliable foundation for non-invasive clinical monitoring. Conclusions.This study provided a comprehensive framework and practical guidelines for adapting epigenetic clocks to HTS-based cfDNA data, paved the path for more general application of cfDNA-based aging assessment and liquid biopsies.

bioinformatics↗

Activation of IRF7/ISG15 axis in microglia inhibits NLRP3 Expression and Improves the Prognosis of Ischemia/Reperfusion in Mice

Ischemic stroke is a leading cause of disability and mortality, with neuroinflammation playing a key role in post-stroke injury. The molecular mechanisms remain incompletely defined. This study explored the functions of IRF7 and its downstream target ISG15 in stroke-associated neuroinflammation and prognosis of ischemic stroke. Bioinformatic analysis of transcriptomic datasets from microglia and ischemic brain tissues identified both molecules as hub genes. Their expression was validated in a mouse transient middle cerebral artery occlusion (tMCAO) model and in microglial cultures exposed to oxygen-glucose deprivation/reoxygenation (OGD/R). The effects of these molecules were assessed using siRNA knockdown, conditioned media assays with SY5Y neuronal cells, in vivo overexpression of ISG15, histological and functional assessments. Both IRF7 and ISG15 were significantly upregulated after stroke. IRF7 knockdown reduced ISG15 expression, whereas ISG15 knockdown did not affect IRF7, suggesting a unidirectional regulatory relationship. Conditioned media from microglia treated with siIRF7 or siISG15 increased SY5Y cell mortality, with a stronger effect in the siISG15 group, highlighting neuroprotective role of ISG15. ISG15 knockdown also enhanced microglial migration. Conversely, microglial ISG15 overexpression in vivo promoted a shift toward reduced neuroinflammation, improved neuronal survival, and enhanced functional recovery. Mechanistically, ISG15 stabilized NLRP3 protein but more strongly decreased its mRNA stability through accelerated degradation. These findings demonstrate that the activation of IRF7/ISG15 axis in microglia inhibits NLRP3 Expression and improve the prognosis of ischemia/reperfusion in mice, with ISG15 exerting stronger neuroprotective effects. Targeting microglial ISG15 may offer a promising therapeutic strategy for ischemic stroke. MAIN POINTSO_LIISG15 shows a stronger neuroprotective effect than IRF7 in ischemic stroke. C_LIO_LIISG15 stabilizes NLRP3 protein but more strongly decreases its mRNA stability. C_LIO_LIMicroglial ISG15 overexpression in vivo improves the prognosis of ischemic stroke in mice. C_LI

neuroscience↗

Cell cycle-driven epigenetic resetting maintains stem cell fate for shoot branching

Adult mammalian stem cells typically maintain stem cell identity through proliferative quiescence. In contrast, we demonstrate that stem cell maintenance in Arabidopsis bud precursor cells requires active cell-cycle progression. Inhibiting division silences the shoot meristem marker gene SHOOT MERISTEMLESS (STM) and promotes differentiation. Whereas proliferation dilutes H3K27me3 levels to counteract silencing. Meanwhile, we identified two classes of transcription factors recruiting polycomb repressive complex 2 (PRC2) to epigenetically silence STM. The balance between these forces establishes a cell cycle-coupled epigenetic "Sisyphus" mechanism that maintains pluripotency. This cell fate switch is bistable; modeling and experimental data confirm that prolonged quiescence triggers irreversible differentiation. We propose that sequence-dependent PRC2 recruitment in plants enables precise silencing of fate-determining genes, while cell proliferation sustains pluripotency by resetting epigenetic marks.

plant biology↗

Lymphatics unload VEGFR3 in response to the endothelial stress upon VEGFR2 insufficiency

Vascular endothelial growth factor receptor 2 (VEGFR2) is a key target for regulating the endothelial cell lineage and angiogenesis. It is also expressed by lymphatic endothelial cells (LEC) while its participation in the process of lymphangiogenesis remains inadequately characterized. We show in this study that VEGFR2 is highly expressed in dermal initial lymphatic vessels and valves. The induced deletion of pan-endothelial Vegfr2 at the neonatal stage produced a potent suppression of dermal lymphatic growth, including the thinner lymphatic diameter, the decrease of LEC number and lymphatic valves. Mechanistically, the VEGFR2 insufficiency led to a dramatic decrease of lymphatic VEGFR3, a key regulator mediating signals for lymphatic growth and remodeling. The RNA sequencing analysis revealed that GO terms enriched for the downregulated genes included biological processes related to the EC development while pathways related to the hematopoiesis and immune responses were upregulated in the skin of Vegfr2 mutants compared with the littermate controls. This was further confirmed by the RNA-seq analysis of dermal tissues 48 hours after the endothelial Vegfr2 deletion. Consistently, an inhibitory effect on the dermal lymphatic growth was also observed by targeting Vegfr2 in PROX1+ cells, manifesting a similarly altered transcriptome signature. The alteration of lymphatic gene expression was further validated by the siRNA mediated knockdown of Vegfr2 in primary lymphatic endothelial cells, showing a transcriptional trend of LEC to hematopoietic transition. Findings from this study imply that VEGFR2 is required for the maintenance of endothelial identity and its insufficiency may trigger the alteration of lymphatic transcriptional programs to diminish the VEGFR3-mediated lymphangiogenesis.

developmental biology↗

Intermediate tissue oxygen level is required to observe murine FLASH skin sparing

ObjectiveThis study evaluated the hypothesis that baseline tissue oxygen (pO2) would modulate FLASH toxicity sparing in murine skin, using a wide range of pO2 values, with ultra-high dose rate (UHDR) versus conventional dose rate (CDR) irradiation. ApproachMurine leg tissue pO2 was systematically varied and measured during irradiation from a FLASH Mobetron 9 MeV linac at 25 Gy, comparing UHDR ({approx}240 Gy/s) to CDR ({approx}0.16 Gy/s), for radiation induced skin toxicity outcomes. Baseline tissue pO2 was systematically modulated in 5 different treatment cohorts, using different ranges of inhaled gas (room air, 100% oxygen, or carbogen) and through varying limb vascular compression (partial or full). Radiolytic oxygen consumption, gO2 (mmHg/Gy), was quantified in vivo, and induced macroscopic skin toxicity was scored daily post treatment. Main ResultsFLASH skin sparing was observed at a fixed dose of 25 Gy in groups with partial leg clamping (pO2{approx}7{+/-}4mmHg), inhaled air (pO2{approx}12{+/-}6mmHg) and 100% oxygen (pO2{approx}16{+/-}4mmHg), while reduction in ulceration progression was significant only in the air inhalation group. No FLASH effect was observed under anoxic conditions, via complete blood flow occlusion (pO2{approx}0{+/-}1mmHg), or when modulated by inhaled carbogen (pO2{approx}21{+/-}7mmHg). In vivo measurements of radiolytic oxygen consumption, gO2, correlated to initial pO2 under UHDR conditions (pO2{approx}4-16mmHg), with ulceration predominantly occurring at pO2 values above 16mmHg. Inspired carbogen induced the highest pO2 at which point there was no FLASH sparing, for any dose groups between 25 to 15 Gy, despite having large changes in damage with dose. At the specific dose level of 25 Gy studied, the toxicity scores under anoxia for both UHDR and CDR were low (toxicity scores < 1) with no differences observed. SignificanceThese findings point to the fact that moderate and low tissue pO2 is associated with diminished oxygen-mediated damage at UHDR but not CDR, seen with inspired room air or 100% oxygen. Anoxic and hyperoxic murine skin are associated with minimal and maximal radiation damage respectively, but also exhibit no apparent FLASH toxicity sparing effect, with further investigation warranted into if the FLASH toxicity sparing effect persists at higher doses under anoxia.

cancer biology↗

Phosphatidylserine and RhoB connect phosphatidylinositol 4-phosphate and phosphatidic acid metabolism at the plasma membrane

Cells tightly control the homeostatic levels and subcellular localizations of membrane phospholipids through the regulation of the activities of numerous lipid-metabolizing enzymes and lipid transfer proteins. Yet, the mechanisms by which lipid imbalances are sensed and corrected to establish and maintain homeostasis are, in most cases, unknown. Here we present an expanded view of plasma membrane (PM) phosphoinositide metabolism by revealing an unexpected metabolic connection between two key anionic lipids in this membrane, phosphatidylinositol 4-phosphate (PI4P) and phosphatidic acid (PA). PM pools of PI4P are generated by PI 4-kinase Type III (PI4KIII/PI4KA), an essential enzyme whose partial dysfunction leads to numerous hereditary human diseases. We find that depletion of PI4P by pharmacological inhibition of PI4KA increases the activity of phospholipase Ds (PLDs) and the levels of their lipid product, PA, in the PM. Guided by RNA-seq analysis and proximity labeling proteomics, we elucidate how cells connect this PI4P decrease to a compensatory increase in PA levels. Loss of PM PI4P induces a concomitant decrease of phosphatidylserine (PS) levels, and this metabolic rewiring activates a reciprocal relationship between PS synthesis and PLD-mediated PA generation. These metabolic changes also lead to transcriptional and translational upregulation of the small GTPase RhoB, which enhances PLD-mediated PA synthesis and subsequent actin cytoskeletal remodeling. Our study reveals how disease-relevant perturbation of phosphoinositide synthesis induces an integrated response that ultimately boosts levels of PA, a key anionic lipid and metabolic intermediate in phosphoinositide resynthesis.

cell biology↗

Mapping disease critical spatially variable gene programs by integrating spatial transcriptomics with human genetics

Spatial gene expression patterns underlie tissue organization, development, and disease, yet current methods for detecting spatially variable genes (SVGs) lack the flexibility to capture multi-scale structure, ensure robustness across platforms, and integrate with genetic data to assess disease relevance. We present Spacelink, a unified framework that models spatial variability of a gene at both whole-tissue and cell-type resolution using an adaptive mixture of data-driven spatial kernels and summarizes it using an Effective Spatial Variability (ESV) metric. Spacelink achieved up to 3.2x higher detection power over eight existing global SVG and cell-type SVG methods while showing consistently superior FDR control across 34 different simulation settings and also showed superior cross-platform concordance in matched tissue Visium and CosMx datasets. Applied to 3 healthy CosMx human tissues (brain cortex, lymph node, liver), Spacelink revealed that SVGs are highly informative for 113 complex traits and diseases (average GWAS sample size = 340,406). Spacelink showed up to 2.2x higher disease informativeness over competing methods in tissue-relevant complex diseases and traits, conditional on putative non-spatial expression-level confounders. Applied to a mouse organogenesis Stereo-seq atlas (8 developmental stages), Spacelink identified 145 genes with stage-associated ESV within brain independent of mean expression, that are enriched in pathways like Wnt signaling and Rap1 signaling characterizing early and late development, respectively. Integration with in vivo Perturb-seq targeting 35 de novo ASD risk genes revealed that perturbations in excitatory neurons and astrocytes preferentially altered spatially structured downstream gene programs (1.7-2.2x higher average ESV across stages than other cell types), many of which were enriched for polygenic autism GWAS loci. In neurodegeneration, analysis of 32 Visium dorsolateral prefrontal cortex samples spanning Alzheimers disease (AD) pathology stages identified 334 genes with decreasing ESV along amyloid burden (enriched for glycolysis) and 216 genes with decreasing ESV along tau tangle accumulation (enriched for apoptotic pathways). Several AD risk genes (PKM, CLU, GPI) showed conserved reductions in spatial variability with AD pathology in both human and 5xFAD mouse, with PKM linking to a colocalized splicing QTL and amyloid burden QTL variant. These results highlight the utility of Spacelink in decoding spatially variable gene programs that connect tissue architecture to disease genetics.

genomics↗

ODC1 restricts meningeal B cell age-associated-like phenotype and function in multiple sclerosis: a human and experimental study

Meningeal inflammation, as a clinical feature of multiple sclerosis (MS), is associated with worse clinical disease outcomes. In both relapsing and secondary progressive MS and the experimental autoimmune encephalomyelitis (EAE) MS model, the meninges have been found to contain ectopic lymphoid follicles enriched with B cells. The metabolic requirement of meningeal B cell function in MS or EAE is not well elucidated. Using 7-Tesla MRI brain scans of MS patients and leptomeningeal enhancement (LME) as a marker, we found a correlation between meningeal inflammation and metabolites of the arginine/polyamine pathway, a finding recapitulated in the EAE model. Ornithine Decarboxylase (ODC1), the rate limiting enzyme for polyamine biosynthesis, as well as polyamine metabolism was diminished in the dura meningeal B cells from mice with MOG35-55 induced EAE mice as compared to naive controls. Pharmacological inhibition of ODC1 restricted meningeal T cells but promoted meningeal B cell proliferation. B cell-specific deletion of ODC1 resulted in expansion of B cells with age-associated B cell-like phenotype (CD11c+CD21/35-CD23-IgD-) and exacerbated disease in the MOG1-125 EAE model. Together, these findings demonstrate a divergent role of polyamines in regulating B and T cell responses in the meninges during autoimmunity. Significance StatementThis study identified the polyamine pathway to be associated with meningeal inflammation in multiple sclerosis, a clinical phenotype associated with worse disease outcomes and without targeted therapy. Using a mouse experimental model, we found that ODC1, the rate limiting enzyme of the polyamine biosynthesis pathway, was suppressed in meningeal B cells, restricted the development of age-associated B cells in the meninges and limited disease severity. This study elucidated a metabolic pathway regulating meningeal B cell function, informing its therapeutic applications in autoimmune diseases.

immunology↗

Post-inhibitory rebound firing drives hypothalamic activation for male mating

Many behaviorally relevant limbic circuits are dominated by inhibitory connections, raising the question of how neuronal activation arises in such contexts. In male mating, both activation of mPOA and its inhibitory inputs are essential--a paradox previously ascribed to disinhibition. Here, we show that the mPOA largely lacks local inhibitory circuits, arguing against disinhibition. Instead, in vivo recordings reveal that mount-active mPOA neurons are suppressed prior to behavioral onset, and this inhibition negatively correlates with subsequent activation, consistent with post- inhibitory rebound firing (PIR). A biologically plausible conductance-based model demonstrates that synaptic inhibition interacts with T-type Ca{superscript 2} currents -- the ionic basis of PIR -- to promote mPOA neuron firing. Experimentally, bidirectional manipulations of mPOA T-type Ca{superscript 2} channels confirm this mechanism: knockdown reduces PIR and impairs male mating, while overexpression enhances mating. Together, these results identify PIR as a critical mechanism by which inhibition promotes activation in limbic circuits to drive male mating.

neuroscience↗

MOH: a novel multilayer multi-omics heterogeneous graph for single-cell clustering

Cell clustering is crucial in single-cell multi-omics research for identifying distinct cellular populations. Although there has been progress in integrating multi-omics data for clustering, combining more than two types of omics data remains challenging due to the diversity and heterogeneity of these datasets. Traditional approaches typically use heterogeneous graphs that integrate only two types of omics data, constructing graphs with genes and cells as nodes and a single type of edge representing their relationships. However, this method has limitations as it overlooks cell-cell interactions and struggles to capture complex cellular dynamics. Additionally, the graph structure must be redesigned whenever new omics data are introduced, limiting the scalability of these models. To address these issues, we introduce MOH, a novel single-cell clustering algorithm based on a multilayer multi-omics heterogeneous graph. MOH integrates three key single-cell omics types: scRNA-seq, scATAC-seq, and spatial transcriptomics. It constructs a multilayer heterogeneous graph to simultaneously extract and enhance representations from all three omics layers, incorporating both intra-layer and inter-layer edges to capture association and similarity relationships. This enriched representation leads to an accurate clustering results. Extensive experiments show that MOH outperforms six state-of-the-art methods on unsupervised clustering metrics, offering a precise and comprehensive analysis with consistent improvements across all evaluation criteria. Moreover, downstream analyses validate the results, revealing novel biological insights into immune disorder complications in cancer, cancer drug repurposing, and new signaling pathways, which merit further investigation and validation.

bioinformatics↗

A high-quality bread wheat genome unravels adaptive evolution of wheat end-use quality

Understanding the genetics of superior dough performance is essential for improving wheat end-use quality. Here, we presented a de novo assembly of the genome of JM44, a Chinese wheat cultivar known for its exceptional end-use quality. The JM44 genome achieved reference-level quality (QV = 66.74), depicting a complete picture of complex regions containing gluten genes. Our microsynteny analysis across the Triticum-Aegilops complex showed that high-molecular-weight glutenin subunits (HMW-GSs) loci are highly conserved, while low-molecular-weight glutenin subunits (LMW-GSs) and -/{beta}-gliadins exhibited greater structural variation. These variable loci appear to have been preferentially selected by humans and contributed substantially to the evolution of wheat quality traits. Moreover, we observed that epistatic interactions between gluten genes are strong in modern cultivars, but markedly weaker in landraces, indicating the importance of epistatic selection during modern breeding. Our findings shed light on the genomics and evolution of wheat quality traits, providing valuable guidance for future breeding efforts.

genomics↗

Fragaria ananassa DAM4 expression correlates with vegetative growth during endodormancy breaking

Dormancy-Associated MADS-BOX (DAM)3 and DAM4 have been described as potential regulators of winter dormancy in cultivated strawberry (Fragaria x ananassa Duch.). These genes are upregulated under short day conditions and downregulated under chilling conditions. The aim of the current work is to test the hypothesis that the expression of DAM3 and DAM4 correlates negatively with vegetative growth during dormancy induction and breaking. The expression of DAM3 and DAM4 as well as plant morphology and physiology were analyzed during a period of semi-dormancy induction and breaking. Furthermore, DAM3 and DAM4 expression was compared between cultivars with different chill requirements. Lastly, the DAM1, DAM2, DAM3, and DAM4 expression of concurrently growing summer and winter leaves was compared at multiple stages of dormancy-breaking. DAM3 and DAM4 expression negatively correlated with leaf area and petiole length. We conclude that DAM3 and DAM4 expression patterns are consistent with that of regulators of semi-dormancy. DAM4 expression in particular correlates strongly with vegetative growth during semi-dormancy breaking. DAM3 or DAM4 expression were not found to correlate with the cultivar-specific chill requirements. Lastly, no relevant differences in DAM expression were found between summer and winter leaves.

plant biology↗

Development of a replication-defective MPXV platform for fundamental and therapeutic research

The recent global outbreaks of mpox highlight the urgent need for both fundamental research and antiviral development. However, studying monkeypox virus (MPXV), with its large and complex genome, remains challenging due to the requirement for high-containment facilities. Here, we describe a novel strategy for de novo assembly of MPXV clade IIb genomes in bacterial artificial chromosomes using transformation-associated recombination cloning. Leveraging CRISPR-Cas9 and Lambda Red recombination, we engineered replication-defective MPXV particles with dual deletions of OPG96 (M2R) and OPG158 (A32.5L)--genes essential for virion assembly, that are capable of recapitulating key stages of the viral life cycle. Our work demonstrates the utility of replication-defective MPXV particles as a reliable platform for high-throughput antiviral discovery, offering significant advantages for both fundamental virology studies and therapeutic development against orthopoxviruses.

microbiology↗

In vivo AAV9-SB-CRISPR screen identifies fatty acid elongase ELOVL5 as a pro-resolving mediator in lung inflammation

Timely resolution of inflammation is essential to prevent tissue damage and maintain homeostasis. Immunometabolism is critical for innate immunity and inflammation. However, how metabolic enzymes and metabolites contribute to inflammatory resolution remains largely unknown. To identify the key metabolic mediators of inflammation resolution, we generated an AAV9-Sleeping Beauty CRISPR library comprising 17090 sgRNAs targeting 2682 mouse metabolic genes. We then conducted an in vivo CRISPR screen in type II alveolar epithelial cells (AECIIs)-specifically expressing Cas9 mice and uncovered a very long chain fatty acid elongase, ELOVL5, that promoted the resolution of lung inflammation after influenza virus infection. Deficiency of Elovl5 in mouse lung epithelial cells impaired lung inflammation resolution and tissue repair phenotype both in vitro and in vivo. Mechanistically, ELOVL5 bound to STING, inhibiting TBK1 interaction and translocation to the Golgi. These effects ultimately reduced STING-mediated inflammation and promoted AKT1-mediated tissue repair. In addition, ELOVL5 decreased eicosanoid levels in AECIIs to promote lung inflammation resolution. Supplement with ELOVL5 downstream products reversed the increased expression of inflammatory cytokines caused by Elovl5 deficiency. These results support an unrevealed mechanism for polyunsaturated fatty acid metabolism in the resolution of innate inflammation and provide paths toward treating inflammatory diseases through manipulating cellular lipid metabolism.

immunology↗