Abstract Background Inherited cardiomyopathies frequently arise from rare, highly penetrant coding variants with variable clinical expressivity. Recent biobank-scale genome-wide association studies (GWAS) suggest significant polygenic contributions to cardiovascular diseases, including cardiomyopathy. Most GWAS loci map to noncoding regions, which are poorly conserved across species, requiring a human genome context for experimental validation. Methods We created engineered heart tissues (EHTs) from human induced pluripotent stem cell (hiPSC)-derived cardiomyocytes and primary cardiac fibroblasts. We assayed single-cell gene expression and chromatin accessibility to generate comprehensive genome-wide regulatory maps. Open chromatin regions (OCRs) were integrated with chromatin contact information and used to functionally fine-map single nucleotide polymorphisms (SNPs) in cardiomyopathy GWAS. SNPs and their associated regulatory regions were assessed using reporter assays, genome editing, and expression profiling. Results Single-cell RNA-seq of EHTs confirmed populations recapitulating major cell types found in hearts, with advanced cardiomyocyte maturation compared to monolayer hiPSC-cardiomyocytes. More than 400,000 OCRs were resolved to cell type and assayed for canonical transcription factor footprints. Functional fine-mapping of GWAS loci prioritized 5817 variants, and reporter assays on select variants validated allele-specific enhancer activity. We identified a locus harboring significant GWAS signals from both dilated cardiomyopathy and left ventricle ejection fraction in an intergenic region at chr3p25.1. Several of these variants lie in OCRs participating in long range chromatin interactions with SLC6A6 and GRIP2 . Haplotype-resolved and synthetic reporter assays confirmed enhancer activity and narrowed candidate SNPs. CRISPR-deletion of this region reduced expression of both SLC6A6 and GRIP2 , indicating the enhancer regulates the expression of more than one gene. Conclusions EHTs derived from hiPSCs are an experimentally tractable platform for testing the function of noncoding variants as modifiers of cardiomyopathy. Variants fine-mapped from cardiomyopathies using EHT regulatory maps have functional consequences and provide a set of prioritized sites to advance the study of polygenic heart failure liability.

Abstract The efficacy and tissue specificity of RNA therapeutics are critical for clinical translation. Here, by large-scale profiling of the dynamic RNA structurome across four cell lines, we systematically characterized the impact of in vivo target RNA structure and RNA-protein interactions on CRISPR/Cas13d gRNA activity. We identified the structural patterns of high-efficacy gRNA targets and observed that structural differences can lead to variations in efficacy across different cellular contexts. By stabilizing single-stranded structure, RNA-binding proteins also enhanced gRNA efficacy. Leveraging this cell context information, along with approximately 290,000 RfxCas13d screening data, we developed SCALPEL, a deep learning model that predicts gRNA performance across various cellular environments. SCALPEL outperforms existing state-of-the-art models, and most importantly, it enables cell type-specific predictions of gRNA activity. Validation screens across multiple cell lines demonstrate that cellular context significantly influences gRNA performance, even for identical targeting sequences, underscoring the feasibility of cell type-specific knockdown by targeting structural dynamic regions. SCALPEL can also facilitate designing highly efficient virus-targeting gRNAs and gRNAs that robustly knockdown maternal transcripts essential for early zebrafish development. Our method offers a novel approach to develop context-specific gRNAs, with potential to advance tissue- or organ-specific RNA therapies.

ABSTRACT Adaptation to fluctuating nutrient supply is essential for organismal survival, but how cells sense and respond to changes in the abundance of many critical nutrients remains undefined. One such example is the amino acid cysteine, whose reactive thiol group is exploited for diverse cellular functions. Here, by characterizing the machinery required for the conditional degradation of cysteine dioxygenase type I (CDO1), the critical enzyme responsible for cysteine catabolism, we identify a Cul2 E3 ligase complex containing the uncharacterized substrate adaptor LRRC58 that is sensitive to cysteine abundance. When cysteine is replete, LRRC58 activity is restrained through auto-ubiquitination and proteasomal degradation; upon cysteine deprivation, LRRC58 is stabilized to permit CDO1 degradation. Through saturation mutagenesis stability profiling, we systematically validate a structural model of the CDO1-LRRC58 interaction and identify residues at the LRRC58 C-terminus required for cysteine-dependent instability. The LRRC58-mediated degradation of CDO1 is essential to prevent ferroptotic cell death under conditions of cysteine scarcity, and mutations in CDO1 which cause neurodevelopmental defects in humans encode dominant-active proteins refractory to LRRC58 recognition. Altogether, these data reveal the CDO1-LRRC58 axis as a critical regulator of cysteine homeostasis that safeguards neural development.

The population of kisspeptin neurons located in the rostral periventricular area of the third ventricle (RP3V) is thought to have a key role in generating the GnRH surge that triggers ovulation. Using a modified GCaMP fibre photometry procedure, we have been able to record the in vivo population activity of RP3V KISS neurons across the estrous cycle of female mice. A marked increase in GCaMP activity was detected beginning on the afternoon of proestrus that lasted in total for 13±1 hours. This was comprised of slow baseline oscillations with a period of 91±4 min and associated with high frequency rapid transients. Very little oscillating baseline or transient activity was detected at other stages of the estrous cycle. Concurrent blood sampling showed that the peak of the LH surge occurred 3.5±1.1 h after the first baseline RP3V KISS neuron baseline oscillation on the afternoon of proestrus. The time of onset of RP3V KISS neuron oscillations varied between mice and across subsequent proestrous stages in the same mice. To assess the impact of estradiol on RP3V KISS neuron activity, mice were ovariectomized and given an incremental estradiol replacement regimen. Minimal patterned GCaMP activity was found in OVX mice, and this was not changed acutely by any of the estradiol treatments. However, on the afternoon of the expected LH surge, the same oscillating baseline activity with associated transients occurred for 7.1±0.5 h. These observations reveal an unexpected prolonged oscillatory pattern of RP3V KISS neuron activity that is dependent on estrogen and underlies the preovulatory LH surge as well as potentially other facets of reproductive behavior.

Abstract Lipid metabolic reprogramming in the hepatocellular carcinoma (HCC) tumor microenvironment (TME) drives immunosuppression, yet the critical mediators orchestrating tumor-immune crosstalk remain elusive. Here, we identify arachidonic acid (ARA), synthesized via the rate-limiting enzyme FADS1, as a novel oncometabolite that accumulates in TME and fuels hepatocarcinogenesis. Genetic or pharmacological inhibition of FADS1 attenuates ARA level, thereby enhancing CD8+ T cell infiltration and cytotoxicity. Using CRISPR-Cas9 screening of metabolic genes in T cell differentiation, we uncover the ARA pathway as a negative regulator of liver-resident memory CD8+ T cells (TRM). These CXCR6+ TRM exhibit antigen specificity but are impaired by FADS1 overexpression or ARA exposure, compromising anti-tumor immunity during tumor rechallenge. Mechanistically, ARA specifically disrupts IL-15-dependent metabolic fitness in CXCR6+ TRM. Therapeutically, targeting the FADS1-ARA axis synergizes with anti-PD-1 and GPC3-CAR-T therapies. Thus, our study identifies a promising target for ARA-enriched immunosuppressive TME, aiming to improve the effectiveness of immunotherapies in HCC.

Large-scale CRISPR screening in human T cells holds significant promise for identifying genetic modifications that can enhance cellular immunotherapy. However, many genetic regulators of T cell performance in solid tumors may not be readily revealed in vitro. In vivo screening in tumor-bearing mice offers greater physiological relevance, but has historically been limited by low intratumoral T cell recovery. Here, we developed a new model system that achieves significantly higher human T cell recovery from tumors, enabling genome-wide in vivo screens with small numbers of mice. Tumor-infiltrating T cells in this model exhibit hallmarks of dysfunction compared to matched splenic T cells, creating an ideal context for screening for genetic modifiers of T cell activity in the tumor microenvironment. Using this platform, we performed two genome-wide CRISPR knockout screens to identify genes regulating T cell intratumoral abundance and effector function (e.g., IFN-γ production). The intratumoral abundance screen uncovered the P2RY8-Gα13 GPCR signaling pathway as a negative regulator of human T cell infiltration into tumors. The effector function screen identified GNAS (Gαs), a central signaling mediator downstream of multiple GPCRs that sense different suppressive ligands, as a key regulator of T cell dysfunction in tumors. Targeted GNAS knockout rendered T cells resistant to multiple suppressive cues and significantly improved therapeutic performance across diverse solid tumor models. Moreover, combinatorial knockout of P2RY8 (trafficking) and GNAS (effector function) further enhanced overall tumor control, demonstrating that genetic modifications targeting distinct T cell phenotypes can be combined to improve therapeutic potency. This flexible and scalable in vivo screening platform can be adapted to diverse tumor models and pooled CRISPR libraries, enabling future discovery of genetic strategies that equip T cell therapies to overcome barriers imposed by solid tumors.

Synthetic biology aims to engineer or re-engineer living systems. To achieve increasingly complex functionalities, it is beneficial to use higher-level building blocks. In this study, we focus on oscillators as such building blocks, propose novel oscillator-based circuit designs and model the interactions of intracellularly coupled oscillators. We classify these oscillators on the basis of coupling strength: independent, weakly or strongly, and deeply coupled. We predict a range of fascinating dynamic behaviours to arise in these systems, such as the beat phenomenon, amplitude and frequency modulation, period doubling, higher-period oscillations, chaos, resonance, and synchronization, with the aim of guiding future experimental work in bacterial synthetic biology. Finally, we outline potential applications, including oscillator-based computing that integrates processing and memory functions, offering multistate and nonlinear processing capabilities.

The urgent need for decentralized, rapid, and affordable point-of-care (POC) diagnostic tools has been starkly highlighted by recent global health crises, underscoring their critical role in achieving health equity. Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)-Cas systems, repurposed from their revolutionary gene-editing origins, have emerged as a transformative platform technology for molecular diagnostics, offering unparalleled programmability, specificity, and sensitivity for nucleic acid detection. The core of these diagnostics lies in the unique catalytic mechanisms of specific Cas effectors, notably the target-activated, non-specific trans-cleavage activity of Cas12 and Cas13 proteins. This collateral cleavage of reporter molecules provides a powerful intrinsic mechanism for signal amplification, enabling sensitive detection. This review critically examines the rapid evolution of CRISPR-based diagnostics, from their fundamental molecular principles to their real-world applications. Key applications in infectious disease surveillance and management are summarized, including the rapid development of assays for SARS-CoV-2, HIV, and tuberculosis, with a particular focus on adaptations for field-deployable formats such as lateral flow assays. As the technology continues to mature, overcoming remaining hurdles in sample preparation, multiplexing, and reagent stability will be paramount. Ultimately, CRISPR-based diagnostics are poised to become an indispensable and democratizing component of the global health toolkit, empowering frontline healthcare workers and transforming disease control on a global scale.

Acidocalcisomes are evolutionarily conserved acidic organelles that are rich in cations and inorganic phosphate, primarily polyphosphates. In kinetoplastid parasites, acidocalcisomes and their polyphosphate content are essential for osmoregulation and environmental adaptation during host switching. In this organelle, polyphosphate is synthesised and transported to the lumen by the vacuolar transporter chaperone (VTC) complex. Interestingly, unlike yeast VTC, which has five components, only two have been observed in kinetoplastids: Vtc1, which contains only a transmembrane domain and Vtc4, which, in addition to a transmembrane domain, also consists of SPX and catalytic domains. In this study, we used proximity-dependent biotinylation (BioID) in Leishmania tarentolae to identify proteins located close to the VTC complex. The complex was found near several known acidocalcisomal proteins, including membrane-bound pyrophosphatase (mPPase), vacuolar-type H⁺-ATPase (V-H + -ATPase), Ca²⁺-transporting P-type ATPase (Ca 2+ -ATPase), zinc transporter (ZnT), and palmitoyl acyltransferase 2 (PAT2). Importantly, this approach revealed three novel VTC binding partners (VBPs) that colocalise and interact with the complex in acidocalcisomes, as confirmed by confocal microscopy, pulldown assays, and AlphaFold 3 structural predictions. Together, our results expand the acidocalcisome interactome and suggest that the newly identified VBPs may contribute to the structural organisation and regulatory function of the VTC complex in phosphate homeostasis of kinetoplastid parasites. Author summary Protozoan parasites such as Leishmania and Trypanosoma cause serious diseases affecting millions of people worldwide. To better understand how these parasites survive environmental changes during transmission between hosts, we studied a specialised organelle called the acidocalcisome, which stores polyphosphates and helps regulate stress responses. In this work, we used the non-pathogenic Leishmania tarentolae as a safe and cost-effective model that shares key cellular features with disease-causing species. Using a combination of CRISPR-Cas9 genome editing, proximity-based labelling (BioID), confocal microscopy, pulldown assays and AlphaFold 3 structure prediction, we investigated the vacuolar transporter chaperone (VTC) complex, which synthesises and transports polyphosphate into the acidocalcisome lumen. Proximity proteomics identified several known proteins located near the VTC complex, and importantly, led us to discover three novel proteins that interact with it. These findings open new directions for exploring the organisation and regulation of the VTC complex in protozoan parasites. By revealing novel protein interactions, our study contributes to a deeper understanding of parasite biology and may help identify therapeutic targets for treating neglected tropical diseases.

MicroRNAs are small non-coding RNAs that mediate post-transcriptional silencing of most mammalian genes. They are generated in a multi-step process initiated by the Microprocessor, a protein complex composed of DROSHA and DGCR8. Recent studies have described the phenomenon of “cluster assistance”, in which a prototypic primary miRNA hairpin can license the Microprocessor-mediated processing of a clustered suboptimal hairpin in cis . Genetic screening and mechanistic analyses led to the identification of two critical factors for this process, SAFB2 (scaffold attachment factor B2) and ERH (enhancer of rudimentary homolog), which have been shown to associate with the N-termini of DROSHA and DGCR8, respectively, but also form a complex with each other. However, it remains unclear how SAFB2 and ERH can alter the Microprocessor substrate specificity, and whether the described protein-protein interactions are required for cluster assistance. In this study, we determined the crystal structure of the SAFB2-ERH complex, revealing the interaction interface and show that mutation of critical residues weakens complex formation but does not affect cluster assistance. Accordingly, loss of SAFB1 and 2 or of ERH results in overlapping, but not identical defects in primary miRNA biogenesis, suggesting that both factors confer also unique roles in this process. Moreover, our data indicate that SAFB1/2 and ERH are required for efficient Microprocessor feedback regulation, uncovering a clear physiological function of cluster assistance impacting global miRNA abundance. Most importantly, we demonstrate that ERH-mediated cluster assistance does not require its described association with DGCR8, and show that its disruption affects only a small subset of cluster assistance-unrelated pri-miRNAs. Thus, this study reveals dual roles of ERH in primary miRNA biogenesis, one driven by its direct binding to DGCR8, and the other in cluster assistance that does not require DGCR8 binding. Highlights SAFB2 and ERH interact through a defined motif, but formation of this complex is largely dispensable for miRNA cluster assistance. Loss of SAFB1/2 and ERH, respectively, induces overlapping, but not identical defects in primary miRNA biogenesis. Both SAFB2 and ERH are involved in Microprocessor feedback regulation. Processing of suboptimal Microprocessor substrates requires SAFB2 and ERH, suggesting their direct involvement. ERH-mediated cluster assistance does not require its binding to the DGCR8 N-terminus.

SUMMARY AMPK (5′-AMP-activated protein kinase) is an energetic sensor for metabolic regulation and integration. Here, we employed CRISPR/Cas9 to generate non-activatable Ampkα knock-in (KI) mice with mutation of threonine 172 phosphorylation site to alanine, circumventing the limitations of previous genetic interventions that disrupt the protein stoichiometry. KI mice of Ampkα2, but not Ampkα1, demonstrated phenotypic changes with increased fat-to-lean mass, impaired endurance exercise capacity, and diminished mitochondrial maximal respiration and conductance in skeletal muscle. Integrated temporal multi-omic analysis (proteomics/phosphoproteomics/metabolomics) in skeletal muscle at rest and during exercise establishes a pleiotropic yet imperative role of Ampkα2 T172 activation for glycolytic and oxidative metabolism, mitochondrial respiration, and contractile function. Importantly, there is a significant overlap of skeletal muscle proteomic changes in Ampkα2 T172A KI mice with that of type 2 diabetic patients. Our findings suggest that Ampkα2 T172 activation is critical for exercise performance and energy transduction in skeletal muscle and may serve as a therapeutic target for type 2 diabetes.

Abstract Genomic imprinting secures parent-specific gene expression through differential DNA methylation at imprinted control regions (ICRs). However, how unmethylated imprinted alleles resist de novo methylation remains unclear. Using an allelic methylation reporter at the Dlk1-Dio3 ICR and a genome-wide loss-of-function screen, we identify that the zinc finger protein GZF1 specifically binds the unmethylated maternal ICR and protects it from de novo methylation in mouse embryonic stem cells, early development, and oocytes. We further show that this protection occurs independently of Tet-mediated demethylation. A regulatory element containing GZF1 and ZFP57 motifs mediates mutually exclusive, methylation-dependent binding. Loss of either factor causes reciprocal imprinting failure: Gzf1 loss induces maternal allele methylation, H3K4me3 depletion, and silencing of maternal transcripts, whereas Zfp57 loss erases paternal methylation, causing locus maternalization. Gzf1-null mice exhibit postnatal growth retardation, contextualizing cis-deletions of this region and illustrating how imprinting phenotypes may differ when studied through epigenetic perturbation versus genetic deletion. Together, our findings define a reciprocal mechanism by which sequence- and methylation-sensitive factors actively memorize parental epigenetic asymmetry through opposing waves of developmental reprogramming.

Abstract Staphylococcus aureus Cas9 (SaCas9) is smaller than the widely used Streptococcus pyogenes Cas9 (SpCas9) and has been harnessed for gene therapy using an adeno-associated virus vector. However, SaCas9 requires a longer NNGRRT (where N is any nucleotide and R is A or G) protospacer adjacent motif (PAM) for target DNA recognition, thereby restricting the targeting range. Furthermore, the precise nuclease activation mechanism of SaCas9 remains elusive. Here, we rationally engineered a SaCas9 variant (eSaCas9-NNG) with an expanded target scope and reduced off-target activity. The eSaCas9-NNG induced indels and base conversions at endogenous sites bearing NNG PAMs in human cells and mice. We further determined the cryo-electron microscopy structures of eSaCas9-NNG in five distinct functional states, revealing the structural basis for the improved specificity and illuminating notable differences in the activation mechanisms between the small SaCas9 and the larger SpCas9. Overall, our findings demonstrate that eSaCas9-NNG could be used as a versatile genome editing tool for in vivo gene therapy, and improve our mechanistic understanding of the diverse CRISPR-Cas9 nucleases.

Efficient purification remains one of the major bottlenecks in the development of plant-based systems for recombinant protein production. The complex metabolites, particularly polyphenols, which usually cause recombinant protein aggregation during purification. In this study, we identified two key polyphenol oxidase genes, PPOa and PPOb from N.benthamiana as responsible for these effects. Using CRISPR/Cas9, we generated two ppoa;ppob double knockout lines that significantly improved the purification of functional proteins like SARS-CoV-2 Spike trimer and influenza HA trimer. These lines showed reduced polyphenol-protein interactions, minimized aggregation, and higher purification yields. Our work establishes a clean, high-efficiency N. benthamiana chassis for scalable recombinant protein production.

ABSTRACT The mitochondrial disulphide relay is the key machinery for import and oxidative protein folding in the mitochondrial intermembrane space. Among IMS proteins with unknown function, we identified FAM136A as a new substrate of the mitochondrial disulphide relay. We demonstrate a transient interaction between FAM136A and MIA40, and that MIA40 introduces four disulphide bonds in two twin-CX 3 C motifs of FAM136A. Consequently, IMS import of FAM136A requires these cysteines and its steady state levels in intact cells are strongly dependent on MIA40 and AIFM1 levels. Furthermore, we show that FAM136A forms non-covalent homodimers as a mature protein. Acute deletion of FAM136A curtails cellular proliferation capacity and elicits a robust induction of the integrated stress response, coincident with the aggregation and/or depletion of selected IMS proteins including HAX1 and CLPB. Together, this establishes FAM136A as a pivotal component of the IMS proteostasis network, with implications for overall cellular function and health.

Mutations in the ATRX chromatin remodeller predispose to a developmental genetic disorder and cancer, but how it safeguards genome and telomere stability remains unresolved. Here, we uncover critical dependencies for the CTC1-STN1-TEN1 (CST) complex and RAD9A-HUS1-RAD1 (9-1-1) clamp in ATRX deficient cells. ATRX:CST synthetic lethality manifests following accumulation of telomeric G-rich ssDNA, which results in telomere loss and cell death. Conversely, we attribute ATRX:9-1-1 synthetic lethality to genome-wide ssDNA lesions, which compromise DNA replication. We further show ATRX suppresses DNA damage during replication stress by counteracting the activity of the FAM111A protease. We demonstrate that roles of ATRX in telomere maintenance and replication are genetically separable requiring its ATPase activity and PIP-box, respectively, and independently of its DAXX interaction. Collectively, functions of ATRX in suppressing toxic ssDNA lesions are context-dependent and are key to global DNA replication and telomere integrity.

Skeletal muscle formation involves the fusion of myocytes into precisely aligned, multinucleated myofibres. These fibres continue to grow through reiterative rounds of myocyte fusion, incorporating new myonuclei and supporting muscle growth, repair and regeneration over organismal life span. The vertebrate-specific myocyte fusogens, Myomaker (Mymk) and Myomixer (Mymx), are crucial for generating multinucleated skeletal muscles. While the role of the transmembrane protein Mymk is well established, expression dynamics of mymx and the function of the Mymx micropeptide is less well understood. Here, using quantitative imaging and a mymx knockout strain, we explored the impact on myogenesis at different life stages of the zebrafish. We demonstrate that during the initial phase of muscle formation, mymx has a spatiotemporally varied expression across all axes of the developing myotome. On Mymx loss, myotome morphogenesis is disrupted, with both cell and tissue structure impacted. Moreover, we could show differential effects of Mymk versus Mymx loss on myocyte fusion and muscle growth. Finally, we report that perturbation to adult muscle multinucleation and size impacted bone development, again with different phenotypic severities among the two fusogen mutants. Together, our work provides key insights into the interplay between myocyte fusion, myotome morphogenesis and acquisition of final adult form.

Parkinson’s disease (PD) is characterized by α-synuclein accumulation and dopaminergic neuron degeneration, with dopamine (DA) oxidation emerging as a key pathological driver. However, the mechanisms underlying this neurotoxic process remain unclear. Using PD patient-derived and CRISPR-engineered iPSC midbrain dopaminergic neurons lacking DJ-1, we identified defective sequestration of cytosolic DA into synaptic vesicles, which culminated in DA oxidation and α-synuclein accumulation. In-depth proteomics, state-of-the-art imaging, and ultrasensitive DA probes uncovered that decreased VMAT2 protein and function impaired vesicular DA uptake, resulting in reduced vesicle availability and abnormal vesicle morphology. Furthermore, VMAT2 activity and vesicle endocytosis are processes dependent on ATP, which is notably reduced in DJ-1-deficient dopaminergic neurons. ATP supplementation restored vesicular function and alleviated DA-related pathologies in mutant dopaminergic neurons. This study reveals an ATP-sensitive mechanism that regulates DA homeostasis through VMAT2 and vesicle dynamics in midbrain dopaminergic neurons, highlighting enhanced DA sequestration as a promising therapeutic strategy for PD. Teaser Loss of DJ-1 interferes with VMAT2 function and vesicle dynamics, leading to DA oxidation and α-synuclein pathology in PD neurons.

Summary Opioids are potent analgesics often prescribed for the treatment of chronic pain, a condition affecting millions worldwide. Although pain states increase vulnerability to opioid use disorders, the neural mechanisms underlying this interaction remain incompletely understood. The ventral tegmental area (VTA) is a key site for opioid actions, and emerging evidence suggests that pain states and opioid experience both induce transcriptional, molecular, and circuit adaptations in the VTA that contribute to motivated behaviors. However, the transcriptional responses of distinct VTA cell types to each of these factors (alone or in combination) have not been identified. Here, we employed single-nucleus RNA sequencing to comprehensively define transcriptional alterations in the rat VTA to acute morphine administration in a chronic inflammatory pain model. We report that morphine induces gene expression changes primarily in glial cells and dopamine neurons, with minimal effects in other neuronal cell types. Surprisingly, VTA astrocytes and oligodendrocytes exhibited the most robust transcriptional responses to opioid exposure, despite lacking detectable opioid receptor expression. Among the most highly regulated glial genes was Fkbp5 , which encodes a co-chaperone protein that acts in concert with heat shock proteins to modulate stress responses. Using pharmacological and CRISPR-based approaches in rat glial cells and human astrocytes, we demonstrate that regulation of Fkbp5 is mediated indirectly through glucocorticoid signaling rather than direct opioid receptor activation. These findings reveal that glial cells within reward circuits undergo profound transcriptional reprogramming in response to opioids through indirect, stress-hormone mediated mechanisms, highlighting a previously unappreciated non-neuronal contribution to opioid-induced neural adaptations.

The clinical deployment of antibiotics is undermined by antimicrobial resistance. Without new agents to treat antibiotic resistant bacterial infections, mortality rates are predicted to reach 10 million people per year by 2050. Most antibiotics are derived from natural products (NPs) produced by bacteria; however, this resource was abandoned by industry because of high rediscovery rates. We are amid a natural product renaissance fuelled by inexpensive access to genome sequencing and sophisticated bioinformatic tools, which have highlighted that most of the biosynthetic pathways for NPs are not expressed in the laboratory. Here, we engineered the expression of a silent biosynthetic gene cluster harboured by an environmental isolate of Streptomyces albidoflavus . By using a bioinformatics-guided approach, we isolated and structurally characterised a novel glycopeptide antibiotic (GPA) named biffamycin A, which is the smallest GPA known and harbours unprecedented 5-chloro-4-methoxy tryptophan and 3-hydroxy(α- d -mannoysl)- d -lysine moieties. Biffamycin A possesses antimycobacterial and antistaphylococcal bioactivity, including methicillin-vancomycin-resistant Staphylococcus aureus .

Replication and segregation of the nucleus and kinetoplast, the mitochondrial DNA, are tightly coordinated in trypanosomatid parasites, but the signalling pathways that govern this process are unknown. Here, we characterise the mitotic spindle kinase (MSK), a key regulator of this coordination in Leishmania . Using chemical genetics, we engineered an analog-sensitive MSK to inhibit its activity. We show that inhibition of MSK impairs mitotic spindle elongation and blocks both nuclear and kinetoplast segregation, halting cell cycle progression and leading to cell death. We combined chemical genetics with proximity-based phosphoproteomics to identify four substrates: two GTPase-activating proteins, a nuclear segregation protein, and a hypothetical protein. We demonstrate that MSK co-localises with these four proteins in the nucleus, mitotic spindle, kinetoplast, and cytoplasm. Our findings establish MSK as a critical kinase that controls the co-ordinated segregation of the nucleus and kinetoplast, providing a new avenue for understanding cell cycle regulation in Leishmania .

Maintenance of genome integrity is essential for cellular homeostasis, and its perturbation leads to tumorigenesis. Here, we uncover an unanticipated somatic role for the synaptonemal complex protein SYCP1—previously regarded as strictly meiosis-specific—in a broad spectrum of human cancers including breast cancer. Through integrative genomic, proteomic, and functional analyses, we demonstrate that SYCP1 is aberrantly re-expressed in tumor cells, where it actively promotes DNA damage repair, cell cycle progression, and malignant growth. SYCP1 binds chromatin at regulatory elements and directly controls transcriptional programs governing genome maintenance, including key effectors such as CCNB1 , PCNA , RAD51C , and H2AX . Loss of SYCP1 impairs DNA repair kinetics, attenuates tumor cell proliferation and migration, and increases sensitivity to chemotherapeutics cisplatin and gemcitabine. Mechanistically, SYCP1 interfaces with chromatin remodeling complexes and transcription factors SP1 and SP2, modulating their genomic occupancy and facilitating oncogenic transcriptional outputs. Clinically, high SYCP1 expression stratifies patients with poor prognosis and therapy resistance across multiple cancer types. Our findings illuminate a previously unrecognized moonlighting function of SYCP1 in somatic cancer cells and position it as a critical chromatin-associated regulator of genome stability, with implications for biomarker development and therapeutic targeting.

ABSTRACT Background Bcl-2-associated athanogene 3 (BAG3) is a mediator of chaperone assisted selective autophagy, and in the brain, most highly expressed in astrocytes. However, its role in astrocytes remains poorly defined. Given the genetic and pathological links of BAG3 to proteostasis and neurodegenerative diseases, we investigated how BAG3 contributes to astrocyte function and Alzheimer’s disease (AD). Methods SnRNA-seq of the human brain determined cell type expression of BAG3. CRISPR/Cas9 gene editing in human iPSCs, followed by tandem mass tag-mass spectrometry and RNA-sequencing was performed to assess proteomic and transcriptomic changes following BAG3 loss. Co-immunoprecipitation of BAG3 in human astrocytes defined the interactome, with top interactors being validated by western blot (WB), AlphaFold modeling, and proximity ligation assays. In astrocytes, autophagic flux, lysosomal phenotypes, proteasome activity, and endocytic uptake were measured in BAG3 KO and BAG3 WT. Finally, BAG3 expression was assessed in postmortem AD brain by WB and snRNA-seq, and its functional relevance to amyloid-β (Aβ) degradation was tested in co-cultures of BAG3 KO iAs with familial AD neurons. Results In human brain and iPSC models, BAG3 was most highly expressed in astrocytes. Further, BAG3 loss caused greater proteomic disruption in astrocytes than in neurons. In the absence of BAG3, astrocytes showed reduced autophagy, diminished lysosome abundance and activity, and decreased proteasome function. To uncover molecular binding partners of BAG3 that might influence these phenotypes, we performed co-immunoprecipitation, revealing interactions with HSPB8 and other heat shock proteins, proteasome regulators (PSMD5, PSMF1), and the retromer component, VPS35. Integration of BAG3 KO transcriptomic and proteomic datasets pinpointed AD-relevant proteins under post-translational control of BAG3, which included GFAP, BIN1, and HSPB8. HSPB8 levels were markedly reduced in BAG3-deficient astrocytes with overexpression partially rescuing its levels. Loss of astrocytic BAG3 impaired Aβ clearance in co-culture with APP/PSEN1 mutant neurons, directly linking BAG3 to a disease-relevant astrocyte function. Finally, analysis of postmortem brain tissue revealed BAG3 marks a stress-responsive astrocyte subtype in the brain of aged individuals with AD. Conclusions BAG3 binds to key regulators of autophagy, proteasome activity, and retromer function to coordinate astrocyte proteostasis, lysosomal function, and Aβ clearance. These findings position BAG3 as a potential therapeutic target and coordinator of glial protein quality control in neurodegeneration.

CRISPR-based gene drive can address ecological problems by biasing their inheritance coupled with an effector for either population modification of suppression. However, the risk of uncontrolled spread impedes some applications of gene drive. Daisy chain drives have received much attention as a potential approach to overcome this problem. They potentially allow efficient spread in a target population but are ultimately self-limiting. This is achieved by splitting a standard gene drive into multiple dependent elements, where each element can bias the inheritance of another, except one non-driving element. With the successive loss of each chain link, spread of transgenic elements will slow down and eventually stop. Here, we use modelling to assess the population dynamics of suppression daisy chain drives in both panmictic and continuous space models. We find that achieving population elimination through a single release of daisy chain gene drives is possible but difficult, with relatively high requirements for drive performance and release size. These effects are substantially amplified in spatial models. We also constructed two configurations of daisy chain gene drives in Drosophila melanogaster as a proof-of-principle. One is a rescue drive for population modification, and the other aims for population suppression by targeting a female fertility gene. Both functioned within expectations at moderate efficiency in individual crosses. However, the system failed to spread in cage populations because of higher than expected fitness costs. Overall, our study demonstrates that daisy chain systems may be promising candidates for both modification and suppression, but challenges remain in both construction and potential deployment in large regions.

ABSTRACT Genome-wide association studies have identified >1,000 loci associated with clinically important red blood cell (RBC) traits, such as hemoglobin concentration and cell volume. However, few of these associations have been characterized at the molecular level such that most causal genes and variants remain elusive. Here, we performed pooled CRISPR screens in an erythroid cell line to identify genes and regulatory non-coding sequences that control RBC density. We perturbed 556 candidate genes and genomic sequences near 2,114 GWAS variants. We used a density gradient to detect the impact of these CRISPR perturbations on cell density. After validation, we found 17 genes and 13 regions near GWAS variants that regulate cell density. Some of these genes have previously been implicated in RBC biology (e.g. ATP2B4 , CCND3 , EPOR ) although many are novel (e.g. CHTF8 , CTU2 , DNASE2 ). We confirmed that deletions in the osmotic stress response kinase gene OXSR1 increase cell density, and a phosphoproteome analysis in OXSR1-depleted cells indicated that this phenotype is accompanied with a dephosphorylation of the upstream kinase WNK1 and the downstream target KCC3 ( SLC12A6 ). We also combined CRISPR perturbations and RNA-sequencing to show how a non-coding genomic sequence near rs13255015 regulates the expression of the transcription factor ZFAT in cis and SLC4A1 in trans . SLC4A1 encodes Band3, a known regulator of RBC hydration and volume. Our results suggest experimental strategies to characterize GWAS findings and provide new molecular insights into the regulation of complex RBC traits.