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Biology subjects

Sun, L.

Publications and source records attributed to Sun, L..

At least 127 records · Page 7Linked to original sources

SensitiveCancerGPT: Leveraging Generative Large Language Model on Structured Omics Data to Optimize Drug Sensitivity Prediction

ObjectiveThe fast accumulation of vast pharmacogenomics data of cancer cell lines provide unprecedented opportunities for drug sensitivity prediction (DSP), a crucial prerequisite for the advancement of precision oncology. Recently, Generative Large Language Models (LLM) have demonstrated performance and generalization prowess across diverse tasks in the field of natural language processing (NLP). However, the structured format of the pharmacogenomics data poses challenge for the utility of LLM in DSP. Therefore, the objective of this study is multi-fold: to adapt prompt engineering for structured pharmacogenomics data toward optimizing LLMs DSP performance, to evaluate LLMs generalization in real-world DSP scenarios, and to compare LLMs DSP performance against that of state-of-the-science baselines. MethodsWe systematically investigated the capability of the Generative Pre-trained Transformer (GPT) as a DSP model on four publicly available benchmark pharmacogenomics datasets, which are stratified by five cancer tissue types of cell lines and encompass both oncology and non-oncology drugs. Essentially, the predictive landscape of GPT is assessed for effectiveness on the DSP task via four learning paradigms: zero-shot learning, few-shot learning, fine-tuning and clustering pretrained embeddings. To facilitate GPT in seamlessly processing the structured pharmacogenomics data, domain-specific novel prompt engineering is employed by implementing three prompt templates (i.e., Instruction, Instruction-Prefix, Cloze) and integrating pharmacogenomics-related features into the prompt. We validated GPTs performance in diverse real-world DSP scenarios: cross-tissue generalization, blind tests, and analyses of drug-pathway associations and top sensitive/resistant cell lines. Furthermore, we conducted a comparative evaluation of GPT against multiple Transformer-based pretrained models and existing DSP baselines. ResultsExtensive experiments on the pharmacogenomics datasets across the five tissue cohorts demonstrate that fine-tuning GPT yields the best DSP performance (28% F1 increase, p-value= 0.0003) followed by clustering pretrained GPT embeddings (26% F1 increase, p-value= 0.0005), outperforming GPT in-context learning (i.e., few-shot). However, GPT in the zero-shot setting had a big F1 gap, resulting in the worst performance. Within the scope of prompt engineering, performance enhancement was achieved by directly instructing GPT about the DSP task and resorting to a concise context format (i.e., instruction-prefix), leading to F1 performance gain of 22% (p-value=0.02); while incorporation of drug-cell line prompt context derived from genomics and/or molecular features further boosted F1 score by 2%. Compared to state-of-the-science DSP baselines, GPT significantly asserted superior mean F1 performance (16% gain, p-value<0.05) on the GDSC dataset. In the crosstissue analysis, GPT showcased comparable generalizability to the within-tissue performances on the GDSC and PRISM datasets, while statistically significant F1 performance improvements on the CCLE (8%, p-value=0.001) and DrugComb (19%, p-value=0.009) datasets. Evaluation on the challenging blind tests suggests GPTs competitiveness on the CCLE and DrugComb datasets compared to random splitting. Furthermore, analyses of the drug-pathway associations and log probabilities provided valuable insights that align with previous DSP findings. ConclusionThe diverse experiment setups and in-depth analysis underscore the importance of generative LLM, such as GPT, as a viable in silico approach to guide precision oncology. Availabilityhttps://github.com/bioIKEA/SensitiveCancerGPT

bioinformatics↗

Proteome analysis of daily urine samples of pregnant rats unveils developmental processes of fetus as well as physiological changes of mother rats

Significant physiological changes occur in both fetus and mother during pregnancy. Urine proteins have been shown to reflect a wide range of physiological and pathological changes in the body. To comprehensively explore the daily changes in urine proteins during pregnancy, this study employed low-abundance protein-enriched magnetic nanobeads to conduct an in-depth analysis of the daily changes in urine proteins throughout the entire pregnancy of rats. Based on the 3,455 identified urine proteins, fetal and maternal dynamic changes were observed in the pregnancy group compared to the control group, including blastocyst formation and cell division in the early stage of pregnancy, embryonic development and organ morphogenesis in the intermediate and mid-to-late stages of pregnancy, and maternal-specific change such as lactation in the late stage of pregnancy. These results indicate that urine protein can reflect the fetal and maternal dynamic physiological alterations during pregnancy, which suggests the potential value of urine protein analysis in pregnancy health monitoring. It is emphasized that the analysis focuses on the daily variations in the urine proteins, as these daily changes are expected to reveal more dynamic and detailed information about the physiological processes during pregnancy.

developmental biology↗

Conditional success of adaptive therapy: the role of treatment-pausing thresholds revealed by mathematical modeling

Adaptive therapy improves cancer treatment by controlling the competition between sensitive and resistant cells through treatment holidays. This study highlights the critical role of treatmentholiday thresholds in adaptive therapy for tumors composed of drug-sensitive and resistant cells. Using a Lotka-Volterra model, adaptive therapy outcomes are compared with maximum tolerated dose therapy and intermittent therapy outcomes, showing that adaptive therapy success depends critically on the threshold for pausing and resuming treatment and on competitive interactions between cell populations. Three comparison scenarios between adaptive therapy and other therapies emerge: uniform-decline where adaptive therapy underperforms regardless of threshold, conditional-improve where efficacy requires threshold optimization, and uniform-improve where adaptive therapy consistently outperforms alternatives. Tumor composition including initial burden and resistant cell proportion influences outcomes. Threshold adjustments enable adaptive therapy to suppress resistant subclones while preserving sensitive cells, extending progression-free survival. Crucially, this work establishes an optimal control problem for time-to-progression and mathematically proves that under biological constraints like neutral competition or low initial burden, the theoretically optimal strategy is unrealizable as it requires infinitely many treatment holidays, rendering it clinically impractical. These findings emphasize personalized treatment strategies for enhancing long-term therapeutic outcomes. Mathematics Subject Classification92C50,92C42.

systems biology↗

Mapping Anhedonia-Related Damage Network: Insights for TMS Treatment

BackgroundMany studies have explored anhedonia-related functional connectivity (FC), but the findings remain inconsistent. There is a gap in identifying a consistent anhedonia-related damage network and applying it to TMS treatment. MethodsWe systematically reviewed studies on anhedonia-related functional connectivity and identified anhedonia-related brain damage locations. Using a novel functional connectivity network mapping approach applied to a large normative connectome dataset, we mapped these damage locations to anhedonia-related damage networks. Subsequently, transcriptomic analysis was conducted to uncover underlying molecular mechanisms. Additionally, we investigated the application of the anhedonia-related damage network in transcranial magnetic stimulation (TMS) treatment, focusing on changes in FC within this network following TMS treatment and its association with anhedonia improvement, as well as predicting TMS treatment efficacy based on baseline FC within the anhedonia-related damage network. ResultsA total of eight experiments from seven studies using the nucleus accumbens (NAc) as the seed were eligible for functional connectivity network mapping analysis. This study identified an anhedonia-related damage network, primarily characterized by disrupted functional connectivity between the NAc and the default mode network. Transcriptomic analysis revealed gene enrichment associated with synaptic signaling, neuronal development, ion transport, and actin cytoskeleton regulation. TMS treatment increased NAc functional connectivity within the anhedonia-related damage network in the response group, with these changes correlating with improvements in anhedonia. Furthermore, baseline NAc FC within this network demonstrated predictive potential for TMS treatment efficacy. ConclusionThe anhedonia-related damage network was identified, emphasizing its underlying mechanisms and predictive value for TMS in treating anhedonia.

neuroscience↗

A novel virus vB_PshM_Y4 with low similarity to both cultured and uncultured viruses

Viruses are the abundant and diverse biological entities on the Earth. During past decades, our knowledge about genomic diversity of viruses has been greatly expanded through high-throughput sequencing. However, whether traditional isolation method could detect virus that could not be identified by high-throughput sequencing is still unknown. In this study, a novel virus, vB_PshM_Y4, infecting Pseudoalteromonas shioyasakiensis, which is an opportunistic pathogen of economically important marine species, was isolated. After comparing vB_PshM_Y4 with the over 15 million genomes of both cultivated and uncultivated viruses in the NCBI and IMG/VR v4 datasets, no similar genome was identified. This suggests that viral isolation methods can detect novel viruses that may not be identified through high-throughput sequencing. Transmission electron microscopy showed that vB_PshM_Y4 exhibits the myoviral morphology. The virus possesses a double-stranded DNA genome that is 158,231 bp in length, with a G+C content of 30.92%, and contains 226 open reading frames (ORFs). Six ORFs were identified as putative auxiliary metabolic genes (AMGs). Phylogenetic tree and gene content-based network analyses indicated that vB_PshM_Y4 may represent a novel viral species within an unknown family of the Caudoviricetes class. Additionally, biogeographical distribution analysis showed that vB_PshM_Y4 were mainly detected in the Arctic and temperate and tropical epipelagic zones with low abundance. ImportanceThis study suggests that viral isolation could detect novel virus that could not be identified through high-throughput sequencing, contributed to a deeper understanding of the genetic diversity and distribution of Pseudoalteromonas viruses, and offered valuable insights into the prevention and control of opportunistic pathogenic bacteria affecting economically important marine organisms.

microbiology↗

Multiplexed CRISPRi Reveals a Transcriptional Switch Between KLF Activators and Repressors in the Maturing Neocortex

A critical phase of mammalian brain development takes place after birth. Neurons of the mouse neocortex undergo dramatic changes in their morphology, physiology, and synaptic connections during the first postnatal month, while properties of immature neurons, such as the capacity for robust axon outgrowth, are lost. The genetic and epigenetic programs controlling prenatal development are well studied, but our understanding of the transcriptional mechanisms that regulate postnatal neuronal maturation is comparatively lacking. By integrating chromatin accessibility and gene expression data from two subtypes of neocortical pyramidal neurons in the neonatal and maturing brain, we predicted a role for the Kruppel-Like Factor (KLF) family of Transcription Factors in the developmental regulation of neonatally expressed genes. Using a multiplexed CRISPR Interference (CRISPRi) knockdown strategy, we found that a shift in expression from KLF activators (Klf6, Klf7) to repressors (Klf9, Klf13) during early postnatal development functions as a transcriptional switch to first activate, then repress a set of shared targets with cytoskeletal functions including Tubb2b and Dpysl3. We demonstrate that this switch is buffered by redundancy between KLF paralogs, which our multiplexed CRISPRi strategy is equipped to overcome and study. Our results indicate that competition between activators and repressors within the KLF family regulates a conserved component of the postnatal maturation program that may underlie the loss of intrinsic axon growth in maturing neurons. This could facilitate the transition from axon growth to synaptic refinement required to stabilize mature circuits.

neuroscience↗

Reduced inter-subject functional connectivity during movies in autism: Replicability across cross-national fMRI datasets

BackgroundAutism is a neurodevelopmental disorder characterized by repetitive behaviors and difficulties in social communication and interaction. Previous research has shown that these symptoms are linked to idiosyncratic behavioral and brain activity patterns while viewing natural social events in movies. This study aimed to investigate the replicability of brain activity idiosyncrasy in autistic individuals by comparing their inter-subject functional connectivity (ISFC) with that of neurotypical individuals. MethodsWe tested for ISFC differences between autistic and neurotypical groups using functional magnetic resonance imaging (fMRI) data from two independent datasets from Germany (Nneurotypical = 25, 7 Males, 18 Females; Nautism = 22, 12 Males, 10 Females) and Finland (Nneurotypical = 19, Nautism = 18; All males). Participants watched short movie stimuli, and pairwise ISFCs were computed across 273 brain regions. Group differences were evaluated using subject-wise permutation tests for each dataset. ResultsIn both datasets, the autistic group showed lower ISFCs compared to the neurotypical group, specifically between visual regions (e.g., occipital gyrus, cuneus) and parietal regions (e.g., superior and inferior parietal lobules), as well as between visual regions and frontal regions (e.g., inferior frontal gyrus, precentral gyrus). ISFC was higher in the Finnish autistic group in temporal regions associated with sound and speech processing. ConclusionsThe study confirmed the replicability of reduced ISFCs in autistic individuals during naturalistic movie-watching, especially between visual and parietal/frontal brain regions. These findings reinforce the utility of ISFC and naturalistic movie-watching paradigm in studying neural connectivity alterations in autism.

neuroscience↗

Multiomics analysis revealed anti-freezing mechanism of Staphylococcus aureus in its anti-freezing strain

Frozen food is currently a common food type. However, the presence of Staphylococcus aureus contamination caused serious challenge to frozen food safety. In this study, we explored the differences between sensitive strains and anti-freeze strains through multiomics analysis such as proteomics, phosphorylated proteomics, and metabolomics studies to understand the anti-freezing mechanism of S. aureus. This study compared the proteomics, phosphorylated proteomics and metabolomic differences between anti-freeze strains and sensitive strains before and after freezing. pre- and post-freezing, antifreeze strains mainly responded to low temperatures by enhancing antioxidant capacity, energy metabolism and antibiotic synthesis before freezing, while after freezing, bacteria depended more on biofilm formation, nitrogen metabolism and amino acid metabolism to improve frost resistance and adaptability. The ket gene such as sucD and coaD in the energy metabolism and metabolic pathways, gapA1 and tpiA in glucose metabolism and energy balance, asd and gnd in the metabolic pathways of amino acid synthesis and protein synthesis, crtN in the context of protective mechanisms and stress response should be explored furthermore. In metabolomic research, the arginine synthesis pathway, biofilm formation pathway, Adenosine triphosphate-binding cassette transporters and other metabolic pathways deserve special attention and research. IMPORTANCEThis study highlights the importance of understanding the anti-freezing mechanisms of *Staphylococcus aureus* in frozen food safety. By analyzing proteomics, phosphorylated proteomics, and metabolomics, it identifies key pathways like energy metabolism, biofilm formation, and amino acid synthesis that enhance bacterial frost resistance, offering insights for improving food preservation and safety.

microbiology↗

Mutations adjacent to the nucleotide-binding cleft of Arabidopsis thaliana ACTIN7 confer resistance to the actin-disrupting compound latrunculin B

A forward genetic screen identified a dominant-negative Arabidopsis thaliana mutant resistant to growth inhibition caused by the actin-disrupting compound latrunculin B (LatB). Map-based cloning combined with whole-genome sequencing revealed that the mutant referred to here as lbr1 for LatB resistant1 had a point mutation in the AT5G09810 gene, which encodes the vegetative actin (ACT) isoform ACT7. The cytosine to thymine mutation in the second exon of ACT7 of lbr1 led to substitution of proline to serine at position 34 (P34S) adjacent to the nucleotide-binding cleft of the ACT7 protein. Confirmation that ACT7 is the causal gene for the lbr1 phenotype was achieved through transgenic complementation with ACT7 wild type (ACT7WT) and ACT7 P34S (ACT7P34S) constructs. ACT7P34 also rescued the seedling developmental defects and conferred partial resistance to LatB in the recessive act7-5 mutant. Furthermore, expressing a P34S mutation in ACT2 (ACT2P34S), another vegetative ACT isoform, conferred partial LatB resistance to wild type. Finally, site-directed mutagenesis of ACT7 amino acid residues forming putative hydrogen bonds with LatB, based on yeast and mammalian actin docking and structural analyses, reveals domains adjacent to the actin nucleotide-binding cleft crucial for LatBs effects on the plant actin cytoskeleton. HighlightCharacterization of the dominant-negative lbr1 mutant uncovers amino acid residues in the actin protein crucial for latrunculins mechanism of action in plants.

cell biology↗

Super-omics and PCAS reveal rheumatoid arthritis as a tumor-like disease

Rheumatoid arthritis (RA) is a debilitating systemic autoimmune disorder that significantly impairs quality of life. To elucidate the molecular alterations in RA progression, we performed comprehensive super-omics analyses on synovial tissues from patients with joint trauma, arthritis, and RA. These analyses included transcriptomics, proteomics, metabolomics, microbiomics, and fourteen PTMs (phosphorylation, acetylation, lactylation, O-GlcNAc glycosylation, arginine monomethylation, lysine monomethylation, lysine dimethylation, lysine trimethylation, succinylation, malonylation, glutarylation, tyrosine nitration, N-glycosylation, and O-glycosylation). Additionally, we developed a protein-centered association study (PCAS) method to integrate these complex datasets. Using this approach, we identified key proteins, such as STK17B, and its interactors, which may be crucial in RA pathogenesis. Tumor-like features, including aberrant angiogenesis and epithelial-mesenchymal transition, were observed in RA, alongside the potential involvement of oncogenes and tumor suppressor genes. Finally, we constructed a molecular interaction blueprint of RA, providing a comprehensive framework for advancing RA pathogenesis, diagnosis, and therapy.

immunology↗

Biochemical Profiling and Structural Basis of ADAR1-Mediated RNA Editing

ADAR1 is a pivotal regulator in RNA-induced immune responses by catalyzing the conversion of adenosine to inosine on double-stranded RNA. Mutations on ADAR1 are associated with human autoimmune disease, and targeting ADAR1 has been proposed for cancer immunotherapy. However, the molecular mechanisms governing ADAR1-mediated RNA editing remain enigmatic. Here, we provide detailed biochemical and structural characterizations of human ADAR1. Our biochemical profiling reveals that ADAR1 editing is both sequence and RNA duplex length-dependent, but can well tolerate mismatches near the editing site. Moreover, our high-resolution structures of ADAR1-RNA complexes, coupled with mutagenesis studies, revealed the molecular basis for RNA binding, substrate selection, dimerization, and the crucial role of the RNA-binding domain 3 for ADAR1 editing. The ADAR1 structures also help explain the potential defects of disease-associated mutations, where biochemical and RNA-sequencing analysis further indicate some of the mutations preferentially impact the editing of RNAs with short duplex. Our findings illustrate the molecular mechanism of ADAR1 editing and provide clues for deciphering its role in immune regulation and drug targeting. HIGHLIGHTSO_LIBiochemical profiling of ADAR1 RNA substrate preference C_LIO_LIAtomic resolution structures of ADAR1 with two physiological RNA substrates C_LIO_LIDisease-related mutations of ADAR1 preferentially impact RNA editing with short dsRNA. C_LIO_LIRNA-binding domain 3 is essential for ADAR1 RNA capture and editing C_LI

biochemistry↗

State-dependent modulation of spiny projection neurons controls levodopa-induced dyskinesia in a mouse model of Parkinson's disease

In the later stages of Parkinsons disease (PD), patients often manifest levodopa-induced dyskinesia (LID), compromising their quality of life. The pathophysiology underlying LID is poorly understood, and treatment options are limited. To move toward filling this treatment gap, the intrinsic and synaptic changes in striatal spiny projection neurons (SPNs) triggered by the sustained elevation of dopamine (DA) during dyskinesia were characterized using electrophysiological, pharmacological, molecular and behavioral approaches. Our studies revealed that the intrinsic excitability and functional corticostriatal connectivity of SPNs in dyskinetic mice oscillate between the on- and off-states of LID in a cell- and state-specific manner. Although triggered by levodopa, these rapid oscillations in SPN properties depended on both dopaminergic and cholinergic signaling. In a mouse PD model, disrupting M1 muscarinic receptor signaling specifically in iSPNs or deleting its downstream signaling partner CalDAG-GEFI blunted the levodopa-induced oscillation in functional connectivity, enhanced the beneficial effects of levodopa and attenuated LID severity.

neuroscience↗

Genetically Labeled Premyelinating Oligodendrocytes: Bridging Oligodendrogenesis and Neuronal Activity

To myelinate axons, oligodendrocyte precursor cells (OPCs) must stop dividing and differentiate into premyelinating oligodendrocytes (preOLs). PreOLs are thought to survey and begin ensheathing nearby axons, and their maturation is often stalled at human demyelinating lesions. Lack of genetic tools to visualize and manipulate preOLs has left this critical differentiation stage woefully understudied. Here, we generated a knock-in mouse line that specifically labels preOLs across the central nervous system. Genetically labeled preOLs exhibit distinct morphology, unique transcriptomic and electrophysiological features, and do not overlap with OPCs. PreOL lineage tracing revealed that subsets of them undergo prolonged maturation and that different brain regions initiate oligodendrogenesis with the spatiotemporal specificity. Lastly, by fate mapping preOLs under sensory deprivation, we find that neuronal activity functions within a narrow time window of preOL maturation to promote their survival and successful integration. Our work provides a new tool to probe this critical cell stage during axon ensheathment, allowing for fine dissection of axon-oligodendrocyte interactions.

neuroscience↗

Elastase mediated white matter damage in cerebral small vessel disease: Microglia - neutrophils pas de deux

Cerebral small vessel disease (CSVD) leads to an extensive white matter damage associated with cognitive decline, yet the underlying damaging mechanisms remain incompletely understood. Here we established a positive correlation between plasma levels of serine proteinase elastase ELANE and periventricular white matter hyperintensity (PV-WMH) in a cohort of CSVD patients. In a CSVD murine model induced by bilateral carotid artery stenosis (BCAS), upregulated ELANE was detected both in microglia and peripheral blood neutrophils. Genetic ELANE deficiency significantly alleviated oligodendrocyte loss, thereby reducing white matter lesions (WMLs) as well as ameliorating sensorimotor and cognitive impairments in BCAS mice. In vitro studies demonstrated that ELANE triggered time-dependent and dose-dependent oligodendrocyte lineage cell death. Bone marrow transplantation showed that ELANE from microglia and peripheral blood both contributed to WML development and BCAS-induced neurological deficits. Mechanistically, ELANE, accumulated by oligodendrocytes, cleaved the phosphodiesterase domain of 2',3'-cyclic nucleotide 3'-phosphodiesterase (CNPase). Pharmacological inhibition of ELANE with Sivelestat reduced oligodendrocyte loss and WMLs leading to the restoration of white matter integrity and neurological improvements in BCAS mice. In post-mortem brain specimens of CSVD patients ELANE accumulated within WMLs being predominantly localized in microglia (and hence defined as microglial ELANE) rather than in the brain-infiltrating neutrophils. We therefore posit microglial ELANE as an instigator of whiter matter injury in CSVD and suggest its potential therapeutic relevance.

neuroscience↗

The Septin Cytoskeleton is a Novel Regulator of Intestinal Epithelial Barrier Integrity and Mucosal Inflammation

Background and AimsIntestinal epithelial barrier-integrity is essential for human health, and its disruption induces and exacerbates intestinal inflammatory disorders. While the cytoskeleton is critical for maintaining gut barrier-integrity, the role of the septins- the newest family of cytoskeletal proteins- is unknown. To address this knowledge gap, we evaluate the role of SEPT9- a critical component of the septin-cytoskeleton- in intestinal epithelial cell (IEC) barrier permeability and inflammation. MethodsWe developed SEPT9-NeonGreen knockin mice, inducible intestinal epithelial cell (IEC)-specific SEPT9 knockout (KO) mice, and SEPT9-KO human IEC lines. SEPT9 localization was analyzed using super-resolution microscopy. Barrier-integrity was assessed via transepithelial electrical resistance, FITC-dextran flux, and visualization of tight junction (TJ) and adherens junction (AJ) proteins. Dextran sodium sulfate-induced experimental colitis was evaluated in control and KO mice through measuring cytokine expression, immune cell infiltration, and IEC death. SEPT9 expression was examined in intestinal tissue of IBD patients. ResultsSEPT9 overlapped with TJs and AJs at IEC apical junctions. SEPT9 loss resulted in a leaky epithelial barrier due to mislocalization of junctional proteins. SEPT9 interacted with non-muscle myosin IIC (NMIIC) at the IEC apical-junctional actomyosin belt, and its ablation displaced NMIIC from IEC junctions. Loss of NMIIC also caused barrier disruption. SEPT9 KO mice exhibited increased susceptibility to experimental-colitis. SEPT9 expression was significantly reduced in intestinal mucosa of IBD patients. ConclusionSEPT9 regulates intestinal barrier integrity, supporting TJ and AJ assembly through NMIIC recruitment to the actomyosin belt. SEPT9 safeguards the intestinal mucosa during acute inflammation, and its reduced expression in IBD suggests a loss of this protective function. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=126 SRC="FIGDIR/small/629767v1_ufig1.gif" ALT="Figure 1"> View larger version (39K): org.highwire.dtl.DTLVardef@5141dcorg.highwire.dtl.DTLVardef@bae524org.highwire.dtl.DTLVardef@19c8eaorg.highwire.dtl.DTLVardef@d5b218_HPS_FORMAT_FIGEXP M_FIG C_FIG

physiology↗

HCN1 channels in GABAergic amygdalar neurons underpin male-biased aggressive behaviors

Aggression behaviors typically vary between sexes, but the molecular mechanisms driving these disparities in neural coding are unclear. We found that aggression selectively activates GABAergic neurons in the posterior substantia innominata (pSI), an extend amygdala region critical for aggressive behaviors in both sexes of mice, with males exhibiting higher neuronal activity during the attack. Utilizing single-nucleus RNA sequencing, we characterized the diverse molecular landscape of pSI neurons, revealing significant differences in ion channels and hormone regulator genes that may underpin sex-specific aggression. Male GABAergic pSI neurons exhibited remarkable hyperexcitability due to increased Ih currents. Strikingly, modulating HCN1 expression not only adjusted this hyperexcitability but also influenced sexual dimorphism in aggression: silencing HCN1 in the GABAergic pSI neurons reduced male aggression, while its overexpression markedly heightened aggression in females. Furthermore, testosterone was shown to intensify aggression by upregulating HCN1 and remodeling pSI circuits. These findings provide detailed sex-specific molecular mechanisms underlying social behaviors.

neuroscience↗

High-efficiency genomic mapping of chromatin-associated targets with CUT&RUN

The precise regulation of chromatin composition is critical to gene expression and cellular identity, and thus a key component in development and disease. Robust assays to study chromatin features, including histone post-translational modifications (PTMs) and chromatin-associated proteins (e.g., transcription factors or PTM readers), are essential to understand their function and identify novel therapeutic strategies. To this end, Cleavage Under Targets and Release Using Nuclease (CUT&RUN) has emerged as a powerful tool for high-resolution epigenomic profiling. The approach has been successfully applied to numerous cell and tissue types, informing on target genomic distribution with unprecedented sensitivity and throughput. Here, we provide a detailed CUT&RUN protocol from sample collection through data analysis, including best practices and defined controls to ensure specific, efficient, and robust target profiling.

genomics↗

Replication stress marker phospho-RPA2 predicts response to platinum and PARP inhibitors in homologous recombination-proficient ovarian cancer

BackgroundOvarian cancer treatment includes cytoreductive surgery, platinum-based chemotherapy, and often poly (ADP-ribose) polymerase (PARP) inhibitors. Homologous recombination (HR)-deficiency is a well-established predictor of therapy sensitivity. However, over 50% of HR-proficient tumors also exhibit sensitivity to standard-of-care treatments. Currently, there are no biomarkers to identify which HR-proficient tumors will be sensitive to standard-of-care therapy. Replication stress may serve as a key determinant of response. MethodsWe evaluated phospho-RPA2-T21 (pRPA2) foci via immunofluorescence as a potential biomarker of replication stress in formalin-fixed, paraffin-embedded tumor samples collected at diagnosis from patients treated with platinum chemotherapy (discovery cohort: n = 31, validation cohort: n = 244) or PARP inhibitors (n = 87). Recurrent tumors (n = 37) were also analyzed. pRPA2 scores were calculated using automated imaging analysis. Samples were defined as pRPA2-High if > 16% of cells had [&ge;] 2 pRPA2 foci. ResultsIn the discovery cohort, HR-proficient, pRPA2-High tumors demonstrated significantly higher rates of pathologic complete response to platinum chemotherapy than HR-proficient, pRPA2-Low tumors. In the validation cohort, patients with HR-proficient, pRPA2-High tumors had significantly longer survival after platinum treatment than those with HR-proficient, pRPA2-Low tumors. Additionally, the pRPA2 assay effectively predicted survival outcomes in patients treated with PARP inhibitors and in recurrent tumor samples. ConclusionOur study underscores the importance of considering replication stress markers alongside HR status in therapeutic planning. Our work suggest that this assay could be used throughout a patients treatment course to expand the number of patients receiving effective therapy while reducing unnecessary toxicity.

cancer biology↗