Biology subjects

Jang, H.

Publications and source records attributed to Jang, H..

At least 37 records · Page 2Linked to original sources

bioRxiv2025

Imaging Cellular Metabolic Rewiring with SuMMIT-SRS

Cells dynamically rewire their metabolic pathways in response to physiological and pathological cues. Such plasticity is particularly critical in neurons, stem cells, cancer cells, and immune cells, where biosynthetic demands can shift rapidly. However, current metabolic imaging techniques using isotope labeling typically track only one metabolite at a time, limiting their ability to capture the rapid dynamics of complex metabolic networks including coordinated precursor utilization, crosstalk, and turnover. Here, we present Subcellular Multiplexed Metabolic Isotope Tracing Stimulated Raman Scattering microscopy (SuMMIT-SRS), a platform that enables simultaneous visualization of multiple metabolic dynamics at subcellular resolution. By exploiting the distinct vibrational signatures of carbon-deuterium bonds derived from multiple deuterated amino acids, lipids, and monosaccharide tracers, SuMMIT-SRS maps co-regulated DNA, RNA, protein, and lipid synthesis at the same time and resolves various individual amino acid-mediated metabolic pathways within intact cells and tissues. We demonstrate SuMMITs broad utility across Drosophila fat body tissue and developing brain, tumor organoids, aged human neurons, and mouse liver, capturing cell type-specific metabolic rewiring under genetic and pathological perturbations. This approach extends SRS to multiplexed isotope tracing, offering a powerful tool to uncover dynamic and complex biosynthesis programs in development, health, and disease.

bioengineering↗

bioRxiv2025

Genome-wide screening reveals producer-cell modifications that improve virus-like particle production and delivery potency

Engineered virus-like particles (eVLPs) are promising vehicles for transient delivery of gene editing agents. While extensive particle engineering has yielded efficient eVLPs, it remains underexplored whether engineering the cells used to produce eVLPs could further improve eVLP properties. We developed a genome-wide screening approach to systematically investigate how genetic perturbations in producer cells influence eVLP production. This approach generates eVLPs loaded with guide RNAs that identify the genetic perturbation in the cell that produced a particular particle; the abundance of each guide RNA in eVLPs therefore reflects how the corresponding genetic perturbation influences eVLP production or cargo loading. We applied this approach to identify several genes that regulate eVLP cargo expression and loading into particles during the production process. Leveraging these insights, we engineered producer cells that support increased eVLP cargo packaging and a 2- to 9-fold increase in eVLP delivery potency across several cargo, particle, and target-cell types in cultured cells and in mice. Our findings suggest the potential of producer-cell engineering as a useful strategy for improving the utility of eVLPs and related delivery methods.

synthetic biology↗

bioRxiv2025

REV1 inhibition enhances trinucleotide repeat mutagenesis

Trinucleotide repeat (TNR) instability has been implicated in the pathogenesis of numerous neurodegenerative disorders. Because TNR instability causes mutagenesis of the underlying gene, we refer to the repeat instability phenomenon as TNR mutagenesis in this study. While germline expansions destabilize TNR to cause disease anticipation, somatic cell TNR instability drives earlier onset of symptoms and further disease progression. However, the drivers behind these repeat length changes remain unclear. Current models suggest that DNA replication slippage events and the action of genome instability pathways, such as DNA repair, cause TNR mutagenesis. Whether mutagenic polymerases from the translesion synthesis (TLS) pathway result in TNR instability is unclear. TLS polymerases are best at bypassing difficult-to-replicate DNA regions due to bulky lesions or gaps in DNA. While some effects of TLS polymerases on TNR instability have been explored in lower organisms, evidence in human cells is lacking. Using a quantitative GFP reporter with expanded CAG repeats, we show that inhibition of the TLS polymerase REV1 by its inhibitor, JH-RE-06, or siRNA knockdown increases TNR instability and the underlying mutability. These results suggest that REV1 protects Trinucleotide repeat length mutagenesis through potential continuous DNA synthesis when replicative polymerases stall ahead of repeat secondary structures. Collectively, we present evidence of the role of the TLS pathway in TNR instability, with potential implications for understanding mutability mechanisms, disease biology, and therapeutic targeting.

genetics↗

bioRxiv2025

The mechanism of oncogenic PI3K lipid kinase variants at the membrane and their cryptic pockets

Cancer-prone alleles exhibit single hotspot mutations. However, the combination of a cancer hotspot and a weak or moderate mutation (the one-two punch hypothesis) produces same-allele double variants with a significantly different and potentially graded clinical phenotypic spectrum. Oncogenic PI3K variants, which are also associated with benign tumors and neurodevelopmental disorders, offer statistical support for this model. Using atomistic molecular dynamics (MD) simulations, we revealed that PI3K variants with single and double mutations exhibit expanded conformational profiles. Double mutations significantly shift the conformational ensembles toward the active form--a more pronounced effect than a single mutation. These double mutants facilitate nSH2 release, iSH2 shift, and A-loop protrusion in solution, promoting PIP2 substrate recruitment at the membrane. We discovered that observable, potentially drug-targetable cryptic pockets are PI3K mutation-specific. Ab initio discovery of these pockets through simulations is essential for AI-aided virtual drug screening. A key challenge is that a single drug is often ineffective against PI3K variants due to their diverse conformational spectra. To address this, we propose a conformational selection strategy involving a combination of allosteric drugs for variants with graded conformational spectra, particularly those with strong double mutations; we identified such potentially targetable cryptic pockets in double mutants conformers.

biophysics↗

bioRxiv2025

Canagliflozin reprograms the aging hippocampus in genetically diverse UM-HET3 mice and attenuates Alzheimer's-like pathology

Aging is the strongest risk factor for cognitive decline and Alzheimers disease (AD), yet the mechanisms underlying brain aging and their modulation by pharmacological interventions remain poorly defined. The hippocampus, essential for learning and memory, is particularly vulnerable to metabolic stress and inflammation. Canagliflozin (Cana), an FDA-approved sodium-glucose co-transporter 2 inhibitor (SGLT2i) for type 2 diabetes, extends lifespan in male but not female mice, but its impact on brain aging is unknown. Here, we used a multi-omics strategy integrating transcriptomics, proteomics, and metabolomics to investigate how chronic Cana treatment reprograms brain aging in genetically diverse UM-HET3 mice. In males, Cana induced mitochondrial function, insulin and cGMP-PKG signaling, and suppressed neuroinflammatory networks across all molecular layers, resulting in improved hippocampal-dependent learning and memory. In females, transcriptional activation of neuroprotective pathways did not translate to protein or metabolite-level changes and failed to rescue cognition. In the 5xFAD AD model, Cana reduced amyloid plaque burden, microgliosis, and memory deficits in males only, despite comparable peripheral glucose improvements in both sexes. Our study reveals sex-specific remodeling of hippocampal aging by a clinically available SGLT2i, with implications for AD pathology and lifespan extension, and highlights Canas potential to combat brain aging and AD through sex-specific mechanisms.

neuroscience↗

bioRxiv2025

AT1R and Integrin β3 Synergize to Drive Aortic Dissection via Non-Canonical Wnt/β-Catenin Signaling

Aortic dissection (AD), a life-threatening cardiovascular emergency, continues to impose high mortality due to insufficient therapeutic options, as monotherapy targeting angiotensin II type 1 receptor (AT1R) demonstrates limited clinical efficacy. Utilizing single-cell RNA sequencing, we identified integrin {beta}3 as a critical driver of AD progression, with expression levels positively correlated with disease severity. Histopathological validation in human AD specimens and a murine angiotensin II (AngII)-infusion model confirmed marked upregulation of integrin {beta}3 activation. Pharmacological blockade of integrin {beta}3 with Cyclo(-RGDfK) significantly attenuated aortic pathogenesis in vivo, reducing dissection incidence and aortic degeneration. Mechanistically, AngII-mediated AT1R activation induced formation of a receptor complex with integrin {beta}3, triggering its conformational activation. Transcriptomic profiling revealed that activated integrin {beta}3 potentiates vascular endothelial dysfunction by binding glycogen synthase kinase 3{beta} (GSK3{beta}), which stabilizes {beta}-catenin via a non-canonical Wnt signaling axis. This pathway drives endothelial barrier disruption, hallmarks of aortic wall destabilization in AD. Our findings unveil a previously unrecognized synergy between AT1R and integrin {beta}3, implicating aberrant Wnt/{beta}-catenin signaling as a nexus of endothelial injury in AD pathogenesis. These results advocate for a paradigm-shifting dual-therapeutic strategy concurrently targeting AT1R and integrin {beta}3 to restore vascular homeostasis, offering a mechanistically grounded approach to mitigate this lethal disease. This work bridges critical gaps in understanding AD pathophysiology and provides a transformative framework for precision therapeutics.

pharmacology and toxicology↗

bioRxiv2025

Relationship between melanoma vemurafenib tolerance thresholds and metabolic pathway choice and Wnt signaling involvement

Vemurafenib constitutes an important therapeutic for BRAFV600 mutant melanomas, but despite high initial response rates, resistance to BRAF and MEK inhibitors quickly develops. Here, we performed an integrative analysis of metabolomic consequences and transcriptome alterations to uncover mechanisms involved in adaptive vemurafenib resistance (VemR) development and their relationship with vemurafenib tolerance thresholds. We developed BRAFV600E isogenic models of VemR utilizing M14 and A2058 lines, and patient-derived melanomas with V600E or normal BRAF to verify vemurafenib selectivity. MEK or PI3K inhibitors only partially inhibited VemR cell proliferation, indicating cross-resistance to these inhibitors. MITF and {beta}-catenin levels were induced and treatment with Wnt/{beta}-catenin inhibitor ICG-001 restored vemurafenib sensitivity with concomitant reductions in {beta}-catenin-regulated gene expressions, phospho-ERK1/2, and VemR-induced mitochondrial mass and respiration. Targeted metabolite, MitoPlate-S1, Mito-stress and transcriptome/metabolomic analysis showed that melanoma cells with elevated vemurafenib tolerance thresholds such as A2058 VemR cells utilize Wnt/{beta}-catenin signaling for mitochondrial metabolism while VemR cells with low tolerance such as M14 VemR cells rely on Wnt/{beta}-catenin signaling for pentose phosphate pathway. Pathways associated with cytokine-cytokine receptor, ECM receptor, and neuroactive ligand receptor interactions were similarly enriched in BRAFV600E patient-derived melanoma as M14 and A2058 cells whereas distinct pathways involving cell cycle, DNA replication, Fanconi anemia and DNA repair pathways are upregulated in wild type BRAF expressing patient derived melanoma. These data show for the first time that the metabolic pathway choices made by VemR BRAF mutant melanomas are controlled by vemurafenib tolerance and endurance thresholds and Wnt/{beta}-catenin signaling plays a central role in coordinating expression of genes controlling VemR and metabolic pathway shifts.

cancer biology↗

bioRxiv2025

Distinct allosteric networks in CDK4 and CDK6 in the cell cycle and in drug resistance

Cyclin-dependent kinases 4 and 6 (CDK4 and CDK6) are key regulators of the G1-S phase transition in the cell cycle. In cancer cells, CDK6 overexpression often outcompetes CDK4 in driving cell cycle progression, contributing to resistance against CDK4/6 inhibitors (CDK4/6i). This suggests distinct functional and conformational differences between these two kinases, despite their striking structural and sequence similarities. Understanding the mechanisms that differentiate CDK4 and CDK6 is crucial, as resistance to CDK4/6i--frequently linked to CDK6 overexpression--remains a significant therapeutic challenge. Notably, CDK6 is often upregulated in CDK4/6i-resistant cancers and rapidly proliferating hematopoietic stem cells, underscoring its unique regulatory roles. We hypothesize that their distinct conformational dynamics explain their differences in phosphorylation of retinoblastoma protein, Rb, inhibitor efficacy, and cell cycle control. This leads us to question how their dissimilar conformational dynamics encode their distinct actions. To elucidate their differential activities, molecular mechanisms, and inhibitor binding, we combine biochemical assays and molecular dynamics (MD) simulations. We discover that CDK4 and CDK6 have distinct allosteric networks connecting the {beta}3-C loop and the G-loop. CDK6 exhibits stronger coupling and shorter path lengths between these regions, resulting in higher kinase activity upon cyclin binding and impacting inhibitor specificity. We also discover an unrecognized role of the unstructured CDK6 C-terminus, which allosterically connects and stabilizes the R-spine, facilitating slightly higher activity. Our findings bridge the gap between the structural similarity and functional divergence of CDK4 and CDK6, advancing the understanding of kinase regulation in cancer biology. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=107 SRC="FIGDIR/small/640857v2_ufig1.gif" ALT="Figure 1"> View larger version (33K): org.highwire.dtl.DTLVardef@cbdc16org.highwire.dtl.DTLVardef@1de54deorg.highwire.dtl.DTLVardef@195ed04org.highwire.dtl.DTLVardef@1fbc860_HPS_FORMAT_FIGEXP M_FIG C_FIG

molecular biology↗

bioRxiv2025

ERK Allosteric Activation: The Importance of Two Ordered Phosphorylation Events

ERK, a coveted proliferation drug target, is a pivotal kinase in the Ras/ERK signaling cascade. Despite this, crucial questions about its activation have not been fully explored on the foundational, conformational level. Such questions include (i) Why ERKs activation demands dual phosphorylation; (ii) What is the role of each phosphorylation site in the activation loop; and (iii) Exactly how the (ordered) phosphorylation steps affect the conformational ensembles of the activation loop, their propensities and restriction to a narrower range favoring ERKs catalytic action. Here we used explicit molecular dynamics simulations to study ERKs stability and the conformational changes in different stages along the activation process. The initial monophosphorylation event elongates the activation loop to enable the successive phosphorylations, which reintroduce stability/compactness through newly formed salt bridges. The interactions formed by the monophosphorylation are site-dependent, with threonines phosphorylation presenting stronger electrostatic interactions compared to tyrosines. Dual phosphorylated ERKs revealed a compact kinase structure which allows the HRD catalytic motif to stabilize the ATP. We further observe that the hinge and the homodimerization binding site responded to a tri-state signaling code based solely on the phosphorylation degree (unphosphorylated, monophosphorylated, dual phosphorylated) of the activation loop, confirming that the activation loop can allosterically influence distant regions. Last, our findings indicate that threonine phosphorylation as the second step is necessary for ERK to become effectively activated and that activation depends on the phosphorylation order. Collectively, we offer ERKs dual allosteric phosphorylation code in activation and explain why the phosphorylation site order is crucial.

molecular biology↗

bioRxiv2025

LARP6 regulates the mRNA translation of fibrogenic genes in liver fibrosis

Metabolic syndrome and excessive alcohol consumption result in liver injury and fibrosis, which is characterized by increased collagen production by activated Hepatic Stellate Cells (HSCs). LARP6, an RNA-binding protein, was shown to facilitate collagen production. However, LARP6 expression and functionality as a regulator of fibrosis development in a disease relevant model remains elusive. By using snRNA-sequencing, we show that LARP6 is upregulated mainly in HSCs of liver fibrosis patients. Moreover, LARP6 knockdown in human HSCs suppresses fibrogenic gene expression. By integrating eCLIP analysis and ribosome profiling in HSCs, we show that LARP6 interacts with mature mRNAs comprising over 300 genes, including RNA structural elements within COL1A1, COL1A2, and COL3A1 to regulate mRNA expression and translation. Furthermore, LARP6 knockdown in HSC attenuates fibrosis development in human liver spheroids. Altogether, our results suggest that targeting LARP6 in human HSCs may provide new strategies for anti-fibrotic therapy. HighlightsO_LILARP6 is upregulated in liver fibrosis, mainly in HSCs. C_LIO_LILARP6 knockdown in human HSCs reduces liver fibrosis development. C_LIO_LIOf the hundreds of gene targets, LARP6 interacts most with collagen mRNAs. C_LIO_LILARP6 regulates mRNA translation via interaction with 5UTRs. C_LI

cell biology↗

bioRxiv2024

Integrative multiomics analysis of metabolic dysregulation induced by occupational benzene exposure in mice

Background: Type 2 Diabetes Mellitus (T2DM) is a significant public health burden. Emerging evidence links volatile organic compounds (VOCs), such as benzene to endocrine disruption and metabolic dysfunction. However, the effects of chronic environmentally relevant VOC exposures on metabolic health are still emerging. Objective: Building on our previous findings that benzene exposure at smoking levels (50 ppm) induces metabolic impairments in male mice, we investigated the effects of occupationally relevant, below OSHA approved, benzene exposure on metabolic health. Methods: Adult male C57BL/6 mice were exposed to 0.9ppm benzene 8 hours a day for 9 weeks. We assessed measures of metabolic homeostasis and conducted RNA and proteome sequencing on insulin-sensitive organs (liver, skeletal muscle, adipose tissue). Results: This low-dose exposure caused significant metabolic disruptions, including hyperglycemia, hyperinsulinemia, and insulin resistance. Transcriptomic analysis of liver, skeletal muscle, and adipose tissue identified key changes in metabolic and immune pathways especially in liver. Proteomic analysis of the liver revealed mitochondrial dysfunction as a shared feature, with disruptions in oxidative phosphorylation, mitophagy, and immune activation. Comparative analysis with high-dose (50 ppm) exposure showed both conserved and dose-specific transcriptomic changes in liver, particularly in metabolic and immune responses. Conclusions: Our study is the first to comprehensively assess the impacts of occupational benzene exposure on metabolic health, highlighting mitochondrial dysfunction as a central mechanism and the dose-dependent molecular pathways in insulin-sensitive organs driving benzene-induced metabolic imbalance. Our data indicate that current OSHA occupational exposure limits for benzene are insufficient, as they could result in adverse metabolic health in exposed workers, particularly men, following chronic exposure.

pharmacology and toxicology↗

bioRxiv2024

All-Optical Multimodal Mapping of Single Cell Type-Specific Metabolic Activities via REDCAT

Metabolism underlies cell growth, survival, and function, yet its activities vary widely across cell types and tissue environments. Spatially resolving these processes in situ at single-cell resolution is essential to advance our understanding of cellular function and tissue physiology in health and disease. However, existing approaches are limited by either destructive workflows, insufficient spatial resolution and biochemical specificity, or lack of direct linkage to cell identity. Here, we present Raman Enhanced Delineation of Cell Atlases in Tissues (REDCAT), a multimodal all-optical platform that integrates stimulated Raman scattering, autofluorescence redox imaging, second harmonic generation, and high-plex immunofluorescence to co-map metabolic activities and cell types within the same tissue section. REDCAT achieves subcellular resolution profiling of protein, lipid, redox, and nuclear acid metabolism, together with extracellular matrix composition, in both FFPE and fresh-frozen human tissues. Applied to normal lymph nodes, REDCAT delineated distinct redox and lipid remodeling programs across germinal center B-cell zones and immune subsets, highlighting cell-type-specific metabolic specialization. In lymphoma, it revealed profound metabolic reprogramming, including extensive lipid accumulation, nuclear metabolic heterogeneity, and a transitional metabolic state associated with transformation from chronic lymphocytic leukemia to diffuse large B-cell lymphoma, thereby illuminating tumor evolution in situ. In human liver, REDCAT resolved cell-type-specific lipid droplet diversity and zonation-dependent nuclear metabolic gradients, uncovering new principles of spatial metabolic organization. By directly linking cell identity with spatial metabolic states at single-cell or subcellular resolution, REDCAT establishes a broadly applicable framework for studying immune function, tumor progression, and tissue physiology, and offers a new path to deciphering the metabolic basis of health and disease.

cell biology↗

bioRxiv2024

Neural Correlates of Psychedelic, Sleep, and Sedated States Support Global Theories of Consciousness

Understanding neural mechanisms of consciousness remains a challenging question in neuroscience. A central debate in the field concerns whether consciousness arises from global interactions that involve multiple brain regions or focal neural activity, such as in sensory cortex. Additionally, global theories diverge between the Global Neuronal Workspace (GNW) hypothesis, which emphasizes frontal and parietal areas, and the Integrated Information Theory (IIT), which focuses on information integration within posterior cortical regions. To disentangle the global vs. local and frontoparietal vs. posterior dilemmas, we measured global functional connectivity and local neural synchrony with functional magnetic resonance imaging (fMRI) data across a spectrum of conscious states in humans induced by psychedelics, sleep, and deep sedation. We found that psychedelic states are associated with increased global functional connectivity and decreased local neural synchrony. In contrast, non-REM sleep and deep sedation displayed the opposite pattern, suggesting that consciousness arises from global brain network interactions rather than localized activity. This mirror-image pattern between enhanced and diminished states was observed in both anterior-posterior (A-P) and posterior-posterior (P-P) brain regions but not within the anterior part of the brain alone. Moreover, anterior transmodal regions played a key role in A-P connectivity, while both posterior transmodal and posterior unimodal regions were critical for P-P connectivity. Overall, these findings provide empirical evidence supporting global theories of consciousness in relation to varying states of consciousness. They also bridge the gap between two prominent theories, GNW and IIT, by demonstrating how different theories can converge on shared neuronal mechanisms.

neuroscience↗

bioRxiv2024

Anticancer Target Combinations: Network-Informed Signaling-Based Approach to Discovery

While anticancer drug discovery has seen dramatic innovations and successes, sequential single therapies are time-limited by resistance, and combinatorial strategies have been lagging. The number of possible drug combinations is vast. To select drug combinations the oncologist requires knowledge of the optimal combination of proteins to co-target. Currently, combinations that the oncologist considers are primarily from empirical observations and clinical praxis. Our aim is to develop a signaling-based method to discover optimal proteins for the oncologist to co-target with drug combinations, and test it on available, patient-derived data. To temper the expected resistance to single drug regimen, we offer a concept-based stratified pipeline aimed at selecting co-targets for drug combinations. Our strategy is unique in its co-target selection being based on signaling pathways. This is significant since in cancer, drug resistance commonly bypasses blocked proteins by wielding alternative, or complementary, routes to execute cell proliferation. Our network-informed signaling-based approach harnesses advanced network concepts and metrics, and our compiled, tissue-specific co-existing mutations. Co-existing driver mutations are common in resistance. Thus, to mimic cancer and counter drug resistance scenarios, our pipeline seeks co-targets that when targeted by drug combinations, can shut off cancers modus operandi. That is, its parallel or complementary signaling pathways would be blocked. Rotating through combinations could further lessen emerging resistance. We applied it to patient-derived breast and colorectal ESR1|PIK3CA and BRAF|PIK3CA subnetworks. Consistently, in breast cancer, our results suggest co-targeting proteins from the ESR1|PIK3CA subnetwork with an alpelisib-LJM716 combination. In colorectal cancer, they co-target BRAF|PIK3CA with alpelisib, cetuximab, and encorafenib combination. Collectively, our pipelines results are promising, and validated by patient-based xenografts. GRAPHICAL ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=200 SRC="FIGDIR/small/617918v1_ufig1.gif" ALT="Figure 1"> View larger version (65K): org.highwire.dtl.DTLVardef@81dc11org.highwire.dtl.DTLVardef@197012dorg.highwire.dtl.DTLVardef@ce3853org.highwire.dtl.DTLVardef@d3ec3a_HPS_FORMAT_FIGEXP M_FIG C_FIG

bioinformatics↗

bioRxiv2024

mTOR variants activation discovers PI3K-like cryptic pocket, expanding allosteric, mutant-selective inhibitor designs

mTOR plays a crucial role in PI3K/AKT/mTOR signaling. We hypothesized that mTOR activation mechanisms driving oncogenesis can advise effective therapeutic designs. To test this, we combined cancer genomic analysis with extensive molecular dynamics simulations of mTOR oncogenic variants. We observed that conformational changes within mTOR kinase domain are associated with multiple mutational activation events. The mutations disturb the -packing formed by the kAL, k3, k9, k9b, and k10 helices in the kinase domain creating cryptic pocket. Its opening correlates with opening of the catalytic cleft, including active site residues realignment, favoring catalysis. The cryptic pocket created by disrupted -packing coincides with the allosteric pocket in PI3K can be harmoniously fitted by the PI3K allosteric inhibitor RLY-2608, suggesting that analogous drugs designed based on RLY-2608 can restore the packed -structure, resulting in mTOR inactive conformation. Our results exemplify that knowledge of detailed kinase activation mechanisms can inform innovative allosteric inhibitor development.

cancer biology↗

bioRxiv2024

Inhibition of Androgen Receptor Exposes Replication Stress Vulnerability in Prostate Cancer

Standard initial systemic treatment for patients with metastatic prostate cancer includes agents that target androgen receptor (AR) signaling. Despite an initial positive response to these AR pathway inhibitors (ARPIs), acquired resistance remains a significant challenge. We show that treatment of AR-positive prostate cancer cells with the frontline ARPI enzalutamide induces DNA replication stress. Such stress is exacerbated by suppression of translesion DNA synthesis (TLS), leading to aberrant accumulation of single-stranded DNA (ssDNA) gaps and persistent DNA damage biomarkers. We further demonstrate that the TLS inhibitor, JH-RE-06, markedly sensitizes AR-positive prostate cancer cells, but not AR-negative benign cells, to enzalutamide in vitro. Combination therapy with enzalutamide and JH-RE-06 significantly suppresses cancer growth in a syngeneic murine tumor model over vehicle control or individual treatment groups. These findings suggest that AR inhibition broadly triggers DNA replication stress in hormone-sensitive prostate cancer, thereby exposing a unique vulnerability that can be exploited by a TLS-disrupting adjuvant for targeted therapy.

cancer biology↗

bioRxiv2024

Thalamic Roles in Conscious Perception Revealed by Low-Intensity Focused Ultrasound Neuromodulation

The neural basis of consciousness remains incompletely understood. While cortical mechanisms of conscious perception have been extensively investigated in humans, the role of subcortical structures, including the thalamus, remains less explored. Here, we elucidate the causal contributions of different thalamic regions to conscious perception using transcranial low-intensity focused ultrasound (LIFU) neuromodulation. We hypothesize that modulating distinct thalamic regions alters perceptual outcomes derived from Signal Detection Theory. We apply LIFU to healthy human anterior (transmodal-dominant) and posterior (unimodal-dominant) thalamic regions, further subdivided into ventral and dorsal regions, during a near-threshold visual perception task. We show that high duty cycle modulation of the ventral anterior (VA) part of thalamus enhances object recognition sensitivity. Sensitivity enhancement magnitude correlates with the core-matrix cell compositions of the stimulated thalamic region. Connectivity analysis of a large-scale functional magnetic resonance imaging dataset confirms strong transmodal connectivity of VA thalamus with frontoparietal and default-mode networks. We also demonstrate target-invariant effects of high duty cycle LIFU disrupting object categorization accuracy. These findings provide causal insight into the cytoarchitectural and functional organization of the thalamus that shapes human visual experience, especially the role of matrix cell-rich, transmodal-dominant VA thalamus.

neuroscience↗

bioRxiv2024

Dysregulation of the fluid homeostasis system by aging

Chronic dehydration is a leading cause of morbidity for the elderly, but how aging alters the fluid homeostasis system is not well understood. Here, we used a combination of physiologic, behavioral and circuit analyses to characterize how fluid balance is affected by aging in mice. We found that old mice have a primary defect in sensing and producing the anti-diuretic hormone vasopressin, which results in chronic dehydration. Recordings and manipulations of the thirst circuitry revealed that old mice retain the ability to sense systemic cues of dehydration but are impaired in detecting presystemic, likely oropharyngeal, cues generated during eating and drinking, resulting in disorganized drinking behavior on short timescales. Surprisingly, old mice had increased drinking and motivation after 24-hour water deprivation, indicating that aging does not result in a general impairment in the thirst circuit. These findings reveal how a homeostatic system undergoes coordinated changes during aging.

neuroscience↗