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Xiong, Y.

Publications and source records attributed to Xiong, Y..

At least 73 records · Page 4Linked to original sources

ProStab: Prediction of protein stability change upon mutations by protein language and inverse folding models

Predicting protein stability change upon mutation is critical for protein engineering, yet remains limited by the modeling assumptions of physics-based methods and the generalization bottlenecks of data-driven approaches. We present ProStab, a deep learning framework that integrates sequence- and structure-based information, including the mutation-aware sequence embeddings from protein language models and the geometric features extracted via an inverse folding model. Trained on the large-scale Megascale dataset, ProStab demonstrates strong performance across diverse test sets and robust generalization across distribution shifts between the training and test sets. In head-to-head comparisons, ProStab outperforms all state-of-the-art methods with consistently higher Spearman correlation and precision. To evaluate its practical utility, we experimentally validated ProStab-predicted mutations on the model enzyme transaminase. Among the 16 successfully expressed variants, 4 exhibited improved thermal stability. Remarkably, the 1st top-ranked predicted mutation yielded the highest observed enzymatic activity, retaining three-fold that of the wild type after 10 minutes at 40 {degrees}C. To facilitate broader application, a publicly accessible web server has been developed. We envisage that ProStab provides a scalable and accurate platform for intelligent protein stability design.

bioinformatics↗

Myocyte Enhancer Factor 2A Orchestrates Vascular Redox Homeostasis via Direct Transcriptional Activation of SIRT1

Myocyte enhancer factor 2A (MEF2A), a transcription factor implicated in coronary artery disease, remains unexplored in vascular redox regulation. To address this gap and overcome limitations of current antioxidant therapies, we investigated MEF2As role in oxidative defense using human umbilical vein endothelial cells (HUVECs) and murine models. Adenoviral vectors encoding MEF2A-specific shRNA or mRNA were employed to silence or overexpress MEF2A in HUVECs. For in vivo validation, endothelial-targeted MEF2A knockdown was achieved via AAV1-shRNA delivery in mice fed a high-fat diet. Systemic redox status was assessed by measuring reactive oxygen species (ROS), glutathione homeostasis (GSH/GSSG ratio), NADH/NAD+ balance, mitochondrial membrane potential ({Delta}{Psi}m), and 8-hydroxy-2'-deoxyguanosine (8-OHdG). Mechanistic insights were derived from immunofluorescence, qPCR, western blotting, and dual-luciferase reporter assays. MEF2A silencing induced redox imbalance, characterized by elevated ROS, reduced GSH/GSSG ratio, and {Delta}{Psi}m collapse. Conversely, MEF2A overexpression synergized with SIRT1 to restore glutathione pools, maintain NAD+ homeostasis, and suppress ROS under oxidative stress. Chromatin immunoprecipitation confirmed direct MEF2A binding to two cis-elements in the SIRT1 promoter, driving transcriptional activation. In vivo, MEF2A-deficient mice exhibited amplified vascular oxidative damage, including elevated DNA damage marker (8-OHdG) and ROS levels. Downregulation of SIRT1/PGC-1 in MEF2A silenced cells was verified in vivo. Our findings establish MEF2A as a master regulator of endothelial redox defense via the SIRT1-PGC-1 axis, offering a mechanistic foundation for targeting oxidative cardiovascular disorders. This work suggests pharmacological MEF2A activation as a novel strategy for precision antioxidant therapy in vascular medicine.

molecular biology↗

Soluble E-cadherin Drives Brain Metastasis in Inflammatory Breast Cancer

The brain is a common site of relapse in inflammatory breast cancer (IBC), an E-cadherin positive, aggressive form of breast cancer. We found that elevated serum levels of soluble E-cadherin (sEcad), an 80-kDa fragment of E-cadherin, in patients with metastatic IBC correlated with poorer outcomes and increased rates of brain metastases. In our effort to understand the underlying mechanism, we discovered that sEcad binds to XIAP, an inhibitor of cell death, activating the pro-survival NF-k{beta} signaling in tumor cells. We also discovered that sEcad affects the tumor cell microenvironment by enhancing cancer cell adhesion to endothelial cells and inducing reactive astrocytosis in the brain. In addition, we found that sEcad-mediated reactive astrocytosis relies on the CXCL1/CXCL8-CXCR2 axis and treatment with a brain-permeable CXCR2 antagonist reduced brain metastatic burden and prolonged survival. These findings implicate sEcad in brain metastasis and provide new insights into potential therapeutic targets for IBC. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=148 SRC="FIGDIR/small/660428v1_ufig1.gif" ALT="Figure 1"> View larger version (69K): org.highwire.dtl.DTLVardef@10a7c47org.highwire.dtl.DTLVardef@1653278org.highwire.dtl.DTLVardef@d4787corg.highwire.dtl.DTLVardef@132489b_HPS_FORMAT_FIGEXP M_FIG C_FIG HighlightsO_LIHigh serum sEcad levels correlate clinically with poor survival outcomes and development of brain metastasis C_LIO_LIsEcad drives IBC brain metastasis growth in mouse models C_LIO_LIsEcad binds XIAP to activate NFkB and promote anoikis resistance and invasion of IBC cells C_LIO_LIsEcad activates reactive astrocytes and induces CXCR2 expression on tumor cells in vitro and in vivo C_LIO_LICXCR2-IN-1, a brain-permeable CXCR2 antagonist, reduces metastasis and improves survival in IBC brain metastasis models C_LI

cancer biology↗

Multimodal Validation of the Existence of Transitional Cerebellar Progenitors in the Human Fetal Cerebellum

The developing human cerebellum comprises a series of transient progenitor states that are essential for generating diverse neural subtypes, yet the identity and validation of intermediate cell populations bridging stem-like and lineage-committed neuronal precursors remain limited. In our previous single-cell transcriptomic study, we identified a distinct transitional cerebellar progenitor (TCP) population enriched in specific progenitor zones such as the rhombic lip during human fetal cerebellar development. To address the concerns raised in the Matters Arising regarding the existence of the TCP cells, we provide additional multimodal validations of this population. Rigorous reanalysis of our single-cell transcriptomic data, applying stringent quality control measures, validated the quality of TCP cells and their classification as a transcriptionally distinct population. Multiple orthogonal validations of TCP signature genes (SOX11 and HNRNPH1) using RNAscope in situ hybridization, Xenium-based spatial transcriptomics, and immunohistochemistry on additional fetal cerebellar samples across different stages demonstrated the consistent presence of TCPs in the rhombic lip, transitioning from PRTG+ stem-like zones in the ventricular zone at early developmental stages to the subventricular zone overlapping with EOMES+ unipolar brush cell precursors at later stages. TCP-like populations were also independently identified in two fetal cerebellar single-nucleus transcriptomic atlases, and their gene signature was enriched in a cell population associated with aggressive medulloblastomas. Collectively, these multimodal validations confirm the existence of a transitional progenitor population in the human fetal cerebellum, with implications for cerebellar lineage progression and medulloblastoma origin.

developmental biology↗

predicTox: An integrated database of clinical risk frequencies and human gene expression signatures for cardiotoxic drugs

We have used drug-induced transcriptomic responses and whole-genome sequences in healthy human induced pluripotent stem cells (iPSC)-derived cardiomyocyte lines to identify cellular functional pathways and genomic variants potentially associated with the cardiotoxic effects of tyrosine kinase inhibitors (TKIs) and other cancer drugs. Here, we describe predicTox.org, an interactive website that organizes our data and its integration with knowledge from cell pathways and genomic databases. DrugTox summary cards give results of these analyses and metadata for each drug. Fields include FDA Adverse Event Reporting System (FAERS) cardiotoxicity risk scores, cell pathways, and genomic variants potentially associated with drug-induced cardiotoxicity. At a detailed level, predicTox provides ranked lists of pathway signatures that are common for cardiotoxic TKIs, up- and downregulated pathways associated with cardiotoxicity induced by specific TKIs and TKI-regulated genes mapping to those pathways. predicTox provides downloadable lists of drug-induced differentially expressed genes (DEGs) and pathways, drug-related genomic variants associated with cardiotoxicity, all with their statistical metrics, and mathematical models to simulate drug effects on heart physiology. Building on the results of our algorithm for independent reidentification of the well-known rs2229774 variant for anthracycline-induced cardiotoxicity, we describe how our data can be queried to identify potential variants associated with drug-induced cardiotoxicity by affecting a drugs pharmacodynamics and pharmacokinetics.

cancer biology↗

The bivalent epigenetic regulator ULTRAPETALA1 promotes the Arabidopsis floral transition via recruitment of Polycomb histone methyltransferases for H3K27me3 deposition at the FLC locus

Floral induction is a major transition during the plant life cycle that contributes to reproductive fitness in annual and perennial plants. Flowering occurs in response to multiple environmental and endogenous cues. In Arabidopsis thaliana, many of these cues converge on the regulation of the FLOWERING LOCUS C (FLC) gene, which encodes a MADS domain transcription factor that functions as the main floral repressor. Here we demonstrate that the bivalent epigenetic regulator ULTRAPETALA1 (ULT1) is both necessary and sufficient to promote flowering. We identify ULT1 as a novel component of the autonomous pathway (AP) and show that it accelerates flowering by directly repressing FLC transcription. We demonstrate that ULT1 physically associates with the SWINGER (SWN) and CURLY LEAF (CLF) histone methyltransferase components of Polycomb Repressive Complex 2 (PRC2) to regulate FLC transcription by altering the accumulation of H3K27me3 marks. Our data indicate that ULT1 promotes the floral transition by interacting with SWN and CLF to recruit PRC2 to the FLC locus to deposit repressive histone methylation and reduce transcription of this key floral repressor.

plant biology↗

Schistosome exposure and diet induced effects on candidate immune gene expression in an African snail vector

Schistosoma mansoni is a parasitic helminth that is vectored through freshwater snails. While the anti-schistosome defense of the South American snail, Biomphalaria glabrata, is well studied, little is known about the immune response of the African snail, Biomphalaria sudanica. We measured expression of five candidate immune genes in B. sudanica 8, 24, and 72 hours post-exposure to S. mansoni using reverse transcription quantitative PCR. Expression patterns of resistant snails were compared to susceptible snails and those sham exposed. We also assessed how diet (lettuce vs. pellet) affected expression of three genes, given prior findings that pellet-fed snails were more susceptible to S. mansoni. Results indicated that resistant snails constitutively expressed higher levels of superoxide dismutase 1 (SOD1) than susceptible snails, consistent with expression patterns of resistant B. glabrata. Parasite-induced expression occurred at 8 hours in SOD1, biomphalysin, thioester protein 1 (TEP1), and granulin (GRN); however, for biomphalysin and TEP1, induced expression was only detected for susceptible snails. At 24 hours, biomphalysin expression increased in exposed resistant snails, and at 72 hours, all exposed snails decreased biomphalysin expression compared to controls. Parasite-induced expression of SOD1, biomphalysin, TEP1, and GRN supports the hypothesis that these genes play a role in B. sudanica anti-schistosome defense, however increased expression does not necessarily yield clearance of S. mansoni. SOD1 expression was higher in lettuce-fed snails at 8 and 24 hours, consistent with their greater resistance. Together, these results demonstrate the conserved and unique aspects of the B. sudanica anti-schistosome response.

microbiology↗

Oncogene SETDB1s Dual Role in Endometrial Cancer: Driving Tumor Progression and Immune Escape

Oncogene SETDB1, an H3K9 methyltransferase, drives tumorigenesis in various cancers. Using endometrial cancer (EC) as a model, we discovered SETDB1s dual mechanisms in driving EC tumorigenesis and mediating immune evasion. SETDB1 knockout (SETDB1-/-) tumor-bearing mice exhibited prolonged survival of up to 100 days. Transcriptomic profiling of SETDB1-/- EC cells revealed decreased expression of oncogenes (POLR2A, MSH6, FLNA) and increased expression of tumor suppressor genes (PGR, RERG, ZNF582), which indicates that SETDB1 intrinsically promotes EC tumor proliferation by regulating these downstream genes. SETDB1 repressed repeat elements and the interferon pathway, mediating immune evasion extrinsically by inhibiting anti-tumor macrophage infiltration. ChIP-seq analysis showed SETDB1 binding at pericentromeric regions on many chromosomes and numerous ZNFs. Loss of SETDB1 resulted in abnormal cell division. SETDB1-/- tumors displayed reduced proliferation markers (Ki67, pHH3) and increased macrophage infiltration. Mechanistically, SETDB1 promotes CD47 (a dont-eat-me signal) and represses CCL5 and CXCL9 (macrophage and T-cell recruiting chemokines), contributing to immune evasion. M1-like macrophages killed more SETDB1-/- cells in co-culture. Additionally, SETDB1 knockout in mouse EC cells reduced tumor growth in C57BL/6 mice, with increased macrophage and CD4+ T-cell infiltration. Our results indicates that elevated SETDB1 and its target genes can predict higher tumor grade and worse survival, suggesting that targeting SETDB1 could be a promising therapeutic strategy for EC.

cancer biology↗

Molecular and Epigenetic Pathways Underlying Epithelial Damage and Repair in Necrotizing Enterocolitis via Multi-omics Approach

IntroductionNeonatal necrotizing enterocolitis (NEC) is a severe gastrointestinal disorder with high mortality, characterized by epithelial cell injury and compromised epithelial repair. The mechanisms underlying defective epithelial regeneration remain poorly understood despite advances in single-cell omics. Addressing these challenges is essential for elucidating the pathogenesis of NEC and identifying therapeutic targets to restore epithelial regeneration and replace the damaged epithelial layer. MethodsMulti-omics approaches were employed to investigate molecular and spatial changes in experimental NEC at epigenetic and transcriptomic levels. These included bulk RNA sequencing, single-nucleus RNA sequencing (snRNA-seq), single-nucleus assay for transposase-accessible chromatin sequencing (snATAC-seq), and multiplexed error-robust fluorescence in situ hybridization (MERFISH) for spatial transcriptomics. Complementary in vitro experiments and in vivo mouse models were utilized to evaluate NEC phenotypes, intestinal tissue morphology, and organoid formation. ResultsChanges in cell type composition, transcriptional network remodeling, and chromatin accessibility were observed in the small intestine of neonatal mice with NEC. Chromatin accessibility significantly changed in epithelial cells, highlighting their pivotal roles in NEC. A marked reduction in intestinal stem cells (ISCs) and transit-amplifying cells, along with an increased proportion of enteroendocrine cells, indicates disrupted epithelial regeneration and functional differentiation. These changes correlated with disrupted WNT signaling and stem cell maintenance genes (e.g., Lgr5, Smoc2, Axin2) and activation of inflammatory and hypoxia-related pathways (e.g., Il6, Tnf). The epigenetic regulator Ezh2 was identified as a critical factor in maintaining LGR5+ ISCs and epithelial homeostasis. Knockdown of Ezh2 reduced stemness and proliferation-related gene expression and exacerbated inflammation. Reactivation of WNT signaling restored Ezh2 and Lgr5 expression, improving intestinal regeneration. ConclusionThis study reveals dynamic transcriptomic, epigenetic, and spatial changes in NEC and highlights Ezh2 as a key regulator of LGR5+ intestinal stem cell function and epithelial regeneration. These findings provide insights into NEC pathogenesis and a basis for therapies targeting Ezh2 and WNT signaling to restore intestinal integrity. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=194 SRC="FIGDIR/small/647851v1_ufig1.gif" ALT="Figure 1"> View larger version (53K): org.highwire.dtl.DTLVardef@1ad89eaorg.highwire.dtl.DTLVardef@396282org.highwire.dtl.DTLVardef@172596forg.highwire.dtl.DTLVardef@4daf28_HPS_FORMAT_FIGEXP M_FIG C_FIG

pathology↗

Obesity Increases Atherosclerosis Susceptibility via Inter-tissue miR-30e-SLC7A11 Axis

BackgroundWith obesity as a risk factor for atherosclerotic disease, recent research suggests that adipose tissue in obese animal models and humans can generate endocrine-like molecules that affect arterial health later on. Previous studies showed that microRNA-30e (miR-30e) level is elevated in atherosclerosis and solute carrier family 7 member 11 (SLC7A11), a cystine/glutamate transporter, is involved in atherogenesis. However, whether an endocrine-like link between the adipose-derived miR-30e-5p and SLC7A11 in the vascular endothelium can lead to obesity-caused atherosclerosis is unknown. MethodsMiRNA data mining and RT-PCR validations were used to demonstrate the positive association among serum level of miR-30e-5p, obesity, and coronary arterial disease in human patients. Transcriptomics (RNA-seq and single-nucleus RNA-seq), metabolomics, and in silico analysis were used to establish a miR-30e-5p-SLC7A11 regulation of central carbon metabolism, mitochondrial and endothelial cell (EC) function. Mouse models with EC-specific Slc7a11 knockout (EC-Slc7a11-/-) and gain or loss of function of miR-30e-5p were used to elucidate the detrimental role of this endocrine-like axis in obesity-related atherosclerosis. ResultsThe level of adipocyte-derived miR-30e-5p was significantly upregulated in obese humans with coronary artery disease and obese and atherosclerotic mice. Via serum exosomes, the adipocyte-generated miR-30e-5p targeted SLC7A11 mRNA in vascular ECs. SLC7A11 deficiency due to miR-30e-5p targeting dysregulated glutamate/cystine metabolism increased glycolysis, reduced oxidative phosphorylation, and impaired mitochondrial function. The EC dysfunction could be rectified by SLC7A11 overexpression or miR-30e-5p antagonism. Exogenously delivered miR-30e-5p phenocopied the increased atherosclerosis in EC-Slc7a11-/- mice. In contrast, miR-30e-5p antagomir treatment reduced atherosclerosis in Apoe-/- and ob/ob mice. ConclusionOur multi-omics approaches demonstrates that the adipose-derived miR-30e-5p downregulated SLC7A11 mRNA in ECs via tissue crosstalk. The resulting EC dysfunction led to obesity-related atherosclerosis in mice. These findings underscore a causality between obesity and atherosclerosis in the context of cardiovascular-kidney-metabolic syndrome.

molecular biology↗

Unbiased co-occurring mutational landscapes in tumorigenesis

Mutations with a synergistic effect on tumorigenesis were positively selected during tumor evolution, showing a tendency to co-occur in cancer genomes. To systematically gain insight of tumorigenic crosstalk at the mutation level, we utilized the FP-Growth algorithm in frequent pattern mining to create an unbiased map of co-occurring mutations from clinical genome sequencing data. We identified 100,933 frequent co-occurring mutation pairs across 22 cancer types. The co-mutation pairs involving cancer driver genes highlighted potential mechanisms for collaborative tumor formation, suggesting promising targets to disrupt tumorigenesis. Additionally, the large number of intra-gene co-mutations with strong dependencies indicated possible combinational effects on the oncogenic properties of specific proteins, which might be overlooked when individual mutations are not hotspots. Furthermore, our whole-genome mining strategy revealed a significant number of co-mutations in non-coding regions, with an enrichment of regulatory elements suggesting their potential role in modulating the co-expression of related genes. Finally, we demonstrated that our pipeline could systematically identify high-order co-mutations. In summary, our study provides the most extensive co-occurring mutations in tumor development, offering valuable insights into mechanisms and potential therapeutic targets.

bioinformatics↗

Hyperactive PLCG1 drives non-canonical signaling to promote cell survival

One of the long-standing questions in cell signaling field to identify and characterize key signaling nodes out of a complex network. Phospholipase C{gamma}1 (PLCG1) was identified as the most frequently mutated gene in adult T-cell leukemia/lymphoma, suggesting a critical function of PLCG1 in driving T cell activation. However, it remains unclear how these mutations regulate T cell physiology and pathology. Here we investigated three common leukemia/lymphoma associated mutations (R48W, S345F, and D1165H). We discovered that these mutations induced hyperactive T cell signaling and caused pro-survival phenotypes. PLCG1 mutants enhanced LAT condensation, calcium influx, and ERK activation. They promoted T cell proliferation, induced cell aggregation, and rendered resistance to vorinostat, an FDA-approved drug for cutaneous T-cell lymphoma. The resistance to vorinostat depended on ERK signaling and can be reversed with an ERK inhibitor. Mechanistically, alpha smooth muscle actin, which was specifically induced by PLCG1 mutants, directly bound PLCG1 to promote its activation. Together, these results demonstrated that hyperactive PLCG1 promoted T cell survival and drug resistance through inducing non-canonical signaling.

cell biology↗

Structural basis for aminoacylation of cellular modified tRNALys3 by human lysyl-tRNA synthetase

The average eukaryotic tRNA contains 13 posttranscriptional modifications; however, their functional impact is largely unknown. Our understanding of the complex tRNA aminoacylation machinery in metazoans also remains limited. Herein, using a series of high-resolution cryo-electron microscopy (cryo-EM) structures, we provide the mechanistic basis for recognition and aminoacylation of fully-modified cellular tRNALys3 by human lysyl-tRNA synthetase (h-LysRS). The tRNALys3 anticodon loop modifications S34 (mcm5s2U) and R37 (ms2t6A) play an integral role in recognition by h-LysRS. Modifications in the T-, variable-, and D-loops of tRNALys3 are critical for ordering the metazoan-specific N-terminal domain of LysRS. The two catalytic steps of tRNALys3 aminoacylation are structurally ordered; docking of the 3'-CCA end in the active site cannot proceed until the lysyl-adenylate intermediate is formed and the pyrophosphate byproduct is released. Association of the h-LysRS-tRNALys3 complex with a multi-tRNA synthetase complex-derived peptide shifts the equilibrium towards the 3'-CCA end docked conformation and allosterically enhances h-LysRS catalytic efficiency. The insights presented here have broad implications for understanding the role of tRNA modifications in protein synthesis, the human aminoacylation machinery, and the growing catalog of metabolic and neurological diseases linked to it.

biochemistry↗

An animal model for autoinflammation with infantile enterocolitis

Inflammasomes, particularly NLRC4, play a crucial role in immune responses to intracellular bacterial infections. However, gain-of-function mutations of NLRC4 are linked to severe autoinflammatory diseases, including autoinflammation with infantile enterocolitis (AIFEC). Existing mouse models do not adequately replicate the chronic, unprovoked inflammation observed in AIFEC patients. In this study, we developed a loxP-flanked NLRC4 V341A knock-in (KI) mouse model. Our global NLRC4 V341A KI mice exhibited symptoms closely mirroring those of human AIFEC. These mice demonstrated severe infantile enterocolitis, characterized by heightened intestinal inflammation, compromised intestinal barrier integrity, disrupted gut epithelium, and severe diarrhea, with high mortality within 10 days postnatally. Additionally, they displayed systemic autoinflammation marked by elevated levels of IL-1{beta}, IL-18, and IL-6, alongside cytopenia and hemophagocytosis. In contrast, adult NLRC4 conditional KI mice exhibited autoinflammation with only mild enterocolitis. Since AIFEC is characterized by life-threatening enterocolitis in infancy and recurrent severe autoinflammation throughout life, our conditional NLRC4 KI model effectively recapitulates the clinical features of human AIFEC. Moreover, the NLRC4 V341A-mediated monogenic infantile enterocolitis observed in our model resembles infantile-onset inflammatory bowel disease (IBD), positioning it as a valuable platform for research on very early-onset IBD.

immunology↗

Target-specific design of drug-like PPI inhibitors via hot-spot-guided generative deep learning

Protein-protein interactions (PPIs) are vital therapeutic targets. However, the large and flat PPI interfaces pose challenges for the development of small-molecule inhibitors. Traditional computer-aided drug design approaches typically rely on pre-existing libraries or expert knowledge, limiting the exploration of novel chemical spaces needed for effective PPI inhibition. To overcome these limitations, we introduce Hot2Mol, a deep learning framework for the de novo design of drug-like, target-specific PPI inhibitors. Hot2Mol generates small molecules by mimicking the pharmacophoric features of hot-spot residues, enabling precise targeting of PPI interfaces without the need for bioactive ligands. The framework integrates three key components: a conditional transformer for pharmacophore-guided, drug-likeness-constrained molecular generation; an E(n)-equivariant graph neural network for accurate alignment with PPI hot-spot pharmacophores; and a variational autoencoder for generating novel and diverse molecular structures. Experimental evaluations demonstrate that Hot2Mol outperforms baseline models across multiple metrics, including docking affinities, drug-likenesses, synthetic accessibility, validity, uniqueness, and novelty. Furthermore, molecular dynamics simulations confirm the good binding stability of the generated molecules. Case studies underscore Hot2Mols ability to design high-affinity and selective PPI inhibitors, demonstrating its potential to accelerate rational PPI drug discovery.

bioinformatics↗

Loss of KDM6A-mediated genomic instability and metabolic reprogramming differentially regulates responses to immune checkpoint therapy and chemotherapy in bladder cancer.

Mutations in genes encoding critical epigenetic regulators are frequently noted in bladder cancer, however, the impact of these mutations on therapeutic efficacy is unclear. One of the most common driver mutations in bladder cancer occurs in the KDM6A gene, which encodes a histone demethylase that promotes gene transcription. Retrospective analyses of patients with bladder cancer demonstrated that KDM6A mutations correlate with improved overall survival (OS) with immune checkpoint therapy (ICT), while they are associated with lower OS in patients undergoing cisplatin-based chemotherapy. Mechanistic studies utilizing CRISPR-Cas9 mediated deletion of Kdm6a showed reduced expression of DNA mismatch repair (MMR) and DNA double-stranded base repair (DSBR) genes in tumor cells with improved response to anti-PD-1 therapy and attenuated sensitivity to cisplatin-based chemotherapy in preclinical models of bladder cancer. Additionally, the loss of Kdm6a-mediated reduction in glycolysis and intratumoral lactate accumulation impaired histone 3 lysine 9 lactylation (H3K9la) and histone 3 lysine 18 lactylation (H3K18la) in Tregs with concurrent decrease in the expression of key genes including Foxp3, Tgfb and Pdcd1 and their immune-suppressive function. Further, reduced expansion of PD-1hi Tregs improved the ratio of cytotoxic T cells to Tregs and response to anti-PD-1 therapy in Kdm6a deficient tumor-bearing mice. Collectively, this study provided key insights into the role of KDM6A-mediated epigenetic regulation of DNA repair and metabolic reprogramming which potentially govern response to chemotherapy and ICT thus highlighting the utility of KDM6A mutation status for patient stratification and development of personalized treatment algorithms.

immunology↗

Altered renal vascular patterning reduces ischemic kidney injury and limits vascular loss associated with aging

The kidney vasculature has a complex arrangement, which runs in both series and parallel to perfuse the renal tissue and appropriately filter plasma. Recent studies have demonstrated that the development of this vascular pattern is dependent on netrin-1 secreted by renal stromal progenitors. Mice lacking netrin-1 develop an arterial tree with stochastic branching, particularly of the large interlobar vessels. The current study investigated whether abnormalities in renal vascular pattern altered kidney function or response to injury. To examine this, we analyzed kidney function at baseline as well as in response to recovery from a model of bilateral ischemic injury and measured vascular dynamics in aged mice. We found no differences in kidney function or morphology at baseline between mice with an abnormal arterial pattern compared to control. Interestingly, male and female mutant mice with stochastic vascular patterning showed a reduction in tubular injury in response to ischemia. Similarly, mutant mice also had a preservation of perfused vasculature with aging compared to a reduction in the control group. These results suggest that guided and organized patterning of the renal vasculature may not be required for normal kidney function; thus, modulating renal vascular patterning may represent an effective therapeutic strategy. Understanding how patterning and maturation of the arterial tree affects physiology and response to injury or aging has important implications for enhancing kidney regeneration and tissue engineering strategies.

cell biology↗

DNA nanodevice for analysis of force-activated protein extension and interactions

AbstractForce-induced changes in protein structure and function mediate cellular responses to mechanical stresses. Existing methods to study protein conformation under mechanical force are incompatible with biochemical and structural analysis. Taking advantage of DNA nanotechnology, including the well-defined geometry of DNA origami and programmable mechanics of DNA hairpins, we built a nanodevice to apply controlled forces to proteins. This device was used to study the R1-R2 segment of the talin1 rod domain as a model protein, which comprises two alpha-helical bundles that reversibly unfold under tension to expose binding sites for the cytoskeletal protein vinculin. Electron microscopy confirmed tension-dependent protein extension while biochemical analysis demonstrated enhanced vinculin binding under tension. The device could also be used in pull down assays with cell lysates, which identified filamins as novel tension-dependent talin binders. The DNA nanodevice is thus a valuable addition to the molecular toolbox for studying mechanosensitive proteins.

biophysics↗