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Search indexed bioRxiv preprints in genomics, neuroscience, cell biology and bioinformatics. Read source abstracts and check manuscript versions; preprints are not peer reviewed.

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RamiGlyph Captures Microglial Morphological Diversity and Predicts Functional States in Ischemia Reperfusion and Amyloid Pathology

Microglia are resident immune cells of the central nervous system, whose ramified processes rapidly remodel in response to injury. However, how to capture subtle morphological changes and whether functional state can be predicted from morphology remain open questions. Here, we present RamiGlyph, a contrastive learning framework integrating topological and structural features, trained on more than 20,000 reconstructed microglia. RamiGlyph not only distinguishes physiological and pathological states of microglia but also generalizes to neuronal cell type classification. Projection of microglia morphological embeddings revealed a continuum rather than discrete classes, from which a morphology score was derived to quantify dynamic process remodeling. To link morphology with function, Gromov Wasserstein optimal transport was used to align unpaired morphological and functional data across stages of ischemia reperfusion injury and amyloid pathology. These alignment results enable prediction of microglial functional states using RamiGlyph embeddings alone, with prediction reliability increasing upon cell aggregation. In summary, RamiGlyph provides a robust framework for resolving continuous microglial morphological variation and linking morphology to functional states across acute and chronic neuropathological contexts.

bioinformatics↗

Striatal cholinergic interneuron pathology and muscarinic signaling independently shape motor dysfunction in a DYT-TOR1A dystonia model

Antimuscarinic drugs are among the most effective pharmacological treatments for dystonia, yet the neural substrates underlying their therapeutic effects remain poorly understood. Striatal cholinergic interneurons (ChI) are strongly implicated in dystonia pathophysiology. In a symptomatic mouse model of DYT-TOR1A dystonia, torsinA loss from all striatal neurons causes selective ChI degeneration during juvenile maturation; surviving ChI exhibit persistent morphological, physiological, and connectivity abnormalities. Whether motor dysfunction arises from ChI degeneration, dysfunction of surviving ChI, or altered cholinergic signaling elsewhere in the striatal circuit remains unknown. Here, we distinguish these mechanisms using complementary genetic, pharmacological, and cell-ablation approaches. Surviving ChI became hyperactive coincident with the emergence of neurodegeneration and abnormal movements. Selective prenatal restoration of torsinA in ChI prevented their degeneration and reduced abnormal movements, identifying ChI as an important cellular locus of torsinA-dependent motor dysfunction. Systemic antimuscarinic treatment during juvenile striatal maturation produced persistent behavioral improvement outlasting treatment without preventing ChI degeneration. Direct intrastriatal antimuscarinic administration nearly abolished abnormal movements, identifying the striatum as a critical site of therapeutic action. Surprisingly, extensive ablation of the remaining dorsal striatal ChI neither prevented nor ameliorated abnormal movements and did not diminish the efficacy of systemic or intrastriatal antimuscarinic treatment. Thus, torsinA-dependent ChI pathology contributes causally to motor dysfunction, yet the continued presence of dorsal striatal ChI is not required for either expression of the motor phenotype or its suppression by muscarinic antagonists. These findings dissociate a developmental contribution of ChI pathology from the striatal mechanisms through which antimuscarinic drugs suppress dystonia-related movements.

neuroscience↗

AMPK reinforces mitochondrial metabolism and suppresses pathological remodeling in Complex V-deficient cardiomyocytes

TMEM70 variants represent the most common nuclear cause of mitochondrial ATP synthase (Complex V) deficiency and are associated with particularly severe cardiac manifestations. Yet, how TMEM70 deficiency disrupts cardiomyocyte metabolic maturation and function remains poorly understood, in part because suitable human disease models are lacking. Here, we model TMEM70-related Complex V deficiency using CRISPR-engineered human induced pluripotent stem cells differentiated into cardiomyocytes. While TMEM70-deficient pluripotent cells retain mitochondrial function, differentiated cardiomyocytes develop reduced mitochondrial membrane potential, impaired respiratory capacity, and pathological remodeling, revealing a differentiation-dependent failure of metabolic maturation. Chronic activation of AMP-activated protein kinase (AMPK) restores mitochondrial respiratory capacity despite persistent Complex V deficiency. Proteomic and metabolomic analyses reveal that AMPK activation in TMEM70-deficient cardiomyocytes reinforces mitochondrial and fatty-acid metabolism while suppressing pathological structural remodeling, accompanied by improved cardiac function. Together, these findings identify AMPK-dependent metabolic remodeling as a state-dependent mechanism of functional rescue in mitochondrial cardiomyopathy.

cell biology↗

Spatiotemporal atlas resolves the mesenchymal-epithelial stem cell axis governing human hair follicle aging and pathology

How adult stem cell populations coordinate tissue regeneration across physiological and pathological states remains unclear. Hair follicles contain epithelial and mesenchymal stem cells that codetermine hair regeneration. Here, we integrate a multimodal spatiotemporal atlas with functional validation to define the mesenchymal-epithelial stem cell dynamics governing human hair follicle homeostasis, aging, and androgenetic alopecia. Aging is characterized by passive depletion of hDSC-derived regenerative cues, whereas AGA involves a shift of hDSC toward an inhibitory signaling hub that promotes HFSC dysfunction. We further pinpoint hDSC-secreted PTN as a key regenerative factor that promotes hair growth and counteracts androgen-induced growth suppression. This study provides a holistic framework of adult stem cell crosstalk across physiological and pathological states, offering a mechanistic roadmap to reinstate tissue regeneration.

cell biology↗

Innate immune stress pathway activation underlies heterochromatin dysfunction pathology

Heterochromatin loss disrupts nuclear architecture, gene regulation and repetitive element silencing, and is associated with diverse human diseases. However, mechanisms linking heterochromatin dysfunction to pathological phenotypes remain unclear. Using genetic interaction screening and genomic analyses in C. elegans, we identify secondary activation of the Intracellular Pathogen Response (IPR), an innate immune stress pathway, as a major contributor to heterochromatin mutant phenotypes. Constitutive IPR activation phenocopies slow growth and indirect transcriptional changes observed in these mutants. Depletion of genetic enhancers further increased, whereas suppressor RNAi attenuated IPR activation, with direct heterochromatin targets remaining substantially deregulated. Notably, many suppressors encode active chromatin components, and mild reduction of RNA polymerase II activity ameliorates growth defects in C. elegans HP1 mutants and human HP1-deficient cells. Our findings reveal secondary stress response activation as an important mechanism linking heterochromatin dysfunction to pathology and identify transcriptional dampening as a potential therapeutic strategy for mitigating these effects.

genetics↗

A First-in-Class, Brain-Penetrant Small Molecule Inhibitor of the NOS1AP-Tau Interaction Rescues Tau Pathology In Vivo and Improves Cognition

NOS1AP is a genetically validated driver of tau pathology in Alzheimer's disease (AD), yet the NOS1AP-tau interaction itself has remained pharmacologically untargeted. We report CAPTOR-1, a first-in-class small molecule that disrupts this interaction by binding a pocket in the N-terminal region of NOS1AP (residues 1-126). A drug-resistant NOS1AP Y16A/F42A variant that retained tau binding but exhibited a 78-fold reduction in CAPTOR-1 affinity provides genetic evidence supporting an on-target mechanism. In human iPSC-derived neurons, CAPTOR-1 dose-dependently reduces endogenous NOS1AP-tau association, tau seeding activity, and pathogenic tau phosphorylation, phenocopying genetic NOS1AP knockdown; these effects extend to neurons from patients with sporadic AD. Orally dosed CAPTOR-1 crosses the blood-brain barrier and engages NOS1AP in brain dose-dependently. Chronic oral dosing rescues pathology, synaptic function, and memory in a tauopathy model (PS19) and an amyloidosis model (APP/PS1), sparing wild-type littermates in both. This work establishes pharmacological disruption of the NOS1AP-tau interaction as a viable, disease-modifying strategy for AD and positions CAPTOR-1 as a biomarker-ready chemical probe (pTau217, neurofilament light) for translational studies.

pharmacology and toxicology↗

ASC specks and α-synuclein amplify microglial NLRP3 inflammasome activation and co-localize with Lewy body pathology

Neuroinflammation is a hallmark of several chronic neurodegenerative disorders, including Parkinson's disease (PD) and other synucleinopathies, and is closely associated with microglial activation. The inflammasome adaptor protein apoptosis-associated speck-like protein containing a caspase activation and recruitment domain (ASC) undergoes oligomerization upon inflammasome activation, resulting in the formation of ASC specks. These structures are recognized by microglia as damage-associated molecular patterns (DAMPs), thereby promoting inflammatory signaling. Recent studies have demonstrated that extracellular ASC specks associate with amyloid-{beta} (A{beta}), and that uptake of ASC-A{beta} composites by microglia amplifies pro-inflammatory responses. Although ASC specks have also been shown to potentiate -synuclein (Syn) preformed fibril-induced pathology, their interaction with monomeric Syn and their effects on inflammasome activation remain poorly understood. Here, we co-stimulated murine SIM-A9 microglia with ASC-Syn assemblies and evaluated their effects on NLRP3 inflammasome activation. Electron microscopy revealed a close association between ASC fibrils and Syn monomers. Exposure of microglia to ASC-Syn enhanced NLRP3 inflammasome activation, as evidenced by increased ASC speck formation, caspase-1 activation, and secretion of IL-1{beta} and IL-18, when compared to ASC or Syn alone. In addition, immunohistochemical analyses of post mortem brain tissue from patients with dementia with Lewy bodies demonstrated ASC expression in regions exhibiting Syn pathology and showed ASC co-localization with Syn within Lewy bodies. Collectively, these findings identify ASC-Syn assemblies as potent amplifiers of NLRP3 inflammasome signaling and suggest a mechanism through which they may contribute to sustained neuroinflammation in synucleinopathies.

neuroscience↗

EEG Pathology Detection via Clinical Concept Bottleneck Models

Deep learning models for electroencephalography (EEG) pathology detection achieve competitive accuracy but offer limited interpretability. In this paper, we introduce concept bottleneck models (CBMs) for EEG pathology detection which use clinical EEG biomarkers computed analytically from the signal as a bottleneck to be used for prediction. Those concepts include band power, spectral ratios, alpha peak frequency and amplitude, hemispheric asymmetry and phase locking values. With the backbone based on shallow convolutional neural network (CNN), we compare a black box baseline with two variants of CBMs. The hybrid variant is a classifier receives a residual projection of the backbone features. The pure variant is a CBM where the classifier receives only the predicted concepts. Models are evaluated on abnormality detection and dementia classification followed by concept prediction quality and leakage analysis. Both CBMs approach the baseline on TUAB (82.7-82.9% vs 83.6%) and are 2-5 percentage points lower on CAUEEG (57.9-60.5% vs 62.7%). The pure CBM exhibits concept fidelity concern where the predicted concepts deviate from their ground truth values. Replacing them with their true values causes severe cost on accuracy by 26 and 22 points on TUAB and CAUEEG. The concept fidelity concern is mitigated by increasing the weight of the concept loss to match the ground truth concepts. the mitigation comes with small accuracy cost on TUAB but a relatively larger cost on CAUEEG. The code of the experiments and full logs are available at https://www.github.com/mhmdrdwn/cbm.

neuroscience↗

Pathological tau leads to network hyperexcitability through neuronal-subtype-specific functional impairment

Pathological tau disrupts neuronal activity and brain function in Alzheimer s disease and other tauopathies. However, the underlying mechanisms for neuronal network dysfunction remain largely unknown. Using human inducible pluripotent stem cell (iPSC) - derived neurons, we show that the familial MAPT P301L mutation leads to neuronal network hyperexcitability. Imbalanced excitation and inhibition were attributable to neuronal subtype-specific tau pathology that was associated with different alterations of tau interactomes in excitatory versus inhibitory neurons. Suppressing enhanced excitatory synaptic transmission or blocking Ca2+ influx resulting from enhanced P301L tau/AHNAK interaction in inhibitory neurons rescued the neuronal network hyperexcitability. This study expands our understanding on how disease-causing tau mutations alter the excitatory/inhibitory balance, leading to network dysfunction in human neurons.

neuroscience↗

Carbonic anhydrase inhibition rescues heart function in the Tg2576 Alzheimer's mouse model by ameliorating cardiac amyloid-β pathology and neurotrophic signaling impairment.

FDA-approved carbonic anhydrase inhibitors (CAIs) have shown robust efficacy in reducing amyloid- beta pathology, neurodegeneration, and cerebrovascular dysfunction in Alzheimer disease (AD) and cerebral amyloid angiopathy (CAA) models, highlighting carbonic anhydrases (CAs) as a promising, previously untapped therapeutic target for AD and the vascular contribution to dementia. We have recently shown that amyloid- beta aggregates disrupt neuro-signaling and deplete neurotrophic factors (particularly BDNF) in the heart of AD mouse models and human subjects. In this study, we present the first in-depth examination of CAI therapy (acetazolamide, ATZ) in Tg2576 mice, a well-established model of AD and CAA. We confirm that progressive cardiac fibrosis and amyloid- beta deposition in 13-month-old mice severely impair the cardiac neuro-signaling system, marked by a drastic decrease in BDNF and reductions in adrenergic fibers and regenerating nerve endings (TH and GAP-43 markers), leading to significant declines in ejection fraction and fractional shortening compared to age-matched WT littermates. Critically, this study demonstrates that long-term ATZ treatment in Tg2576 mice significantly reduces cardiac amyloid- beta burden, prevents adverse neuro-signaling remodeling, and restores heart physiological function, as assessed via speckle tracking strain echocardiography. These in vivo findings were corroborated in human cardiomyocytes, in which CA inhibition reduced human amyloid- beta40 oligomer-dependent disruption of CREB signaling, thus preserving BDNF expression. Together, these results reveal a previously unrecognized cardio-neuroprotective role for CAIs in preventing amyloid- beta-induced cardiovascular remodeling and neuro-signaling disruption in the Tg2576-AD model. Given the established benefits of CAIs on cerebrovascular function and cognition, our findings further support advancing repurposing efforts into clinical trials. CAIs such as ATZ could offer a dual-action therapy approach, addressing both the central nervous system and cardiac pathologies associated with AD and, potentially, the systemic effects of amyloidosis.

cell biology↗

Early Insulin Signaling Defects and Oxidative Stress Kinase Activation Precede Tau Pathology in PS19 Tau Transgenic Mice

Pathological tau accumulation is a hallmark of Alzheimers disease (AD), yet its relationship with impaired insulin signaling remains unclear. Previously, we reported altered IRS1 phosphorylation reduced p IR beta, and GLUT3 expression in young AD transgenic mice prior to overt pathology. Here, we investigated insulin signaling and oxidative stress pathways in the Tau P301S (PS19) mouse model. We found that alterations in phospho IRS1, phospho IR beta, and the glucose transporters GLUT3 and GLUT4 occur before pathogenic tau deposition. In stable tau expressing human neuronal cell lines, tau expression was similarly associated with impaired insulin signaling. Concurrent dysregulation of insulin signaling and activation of oxidative stress responsive kinases, accompanied by increased microglial abundance, were evident in 2 month old PS19 mice and persisted into adulthood. Together, these findings demonstrate that insulin signaling abnormalities and oxidative stress kinase activation are early and sustained features of PS19 tauopathy, preceding the onset of overt neuropathology.

neuroscience↗

BNIP3L/NIX-mediated mitophagy limits Alzheimer disease pathology and preserves neuronal function

Defective mitophagy is emerging as a key contributor to Alzheimer disease (AD), but the neuronal pathways governing mitochondrial clearance and their contribution to disease progression remain poorly understood. Here, we identify BNIP3L/NIX-dependent mitophagy as a conserved neuronal quality control pathway that maintains mitochondrial fitness and constrains AD-associated proteotoxicity. Loss of BNIP3L/NIX or its C. elegans orthologue DCT-1 impaired basal and stressed-induced mitophagy, disrupted mitochondrial homeostasis, enhanced Tau and Amyloid-beta pathology and compromised neuronal network, synaptic and behavioral function across human neuronal and in vivo models. Conversely, restoring BNIP3L/NIX and DCT-1 activity improved neuronal function under proteotoxic stress in vivo, reduced disease-associated Tau phosphorylation in human neurons and markedly suppressed seeded Tau aggregation in primary mouse neurons. Together, these findings identify BNIP3L/NIX-mediated mitophagy as a mechanistic link between mitochondrial quality control, proteostasis and neuronal function, and establish its restoration as a potential strategy for counteracting AD-associated pathology.

cell biology↗

A coordinated and reproducible multicellular response to AD pathology

While single-cell measurements of the Alzheimer's disease (AD) brain allow investigation of vulnerable cells in unprecedented depth, reported findings are heterogeneous, mostly descriptive and often ignore interdependence of cellular responses. Operationalization of these findings requires a multi-cellular model of AD that is robust and reproducible. Here, we utilize a coordinated multicellular community approach across 2.3 million nuclei from 427 ROSMAP donors to identify robust multicellular axes associated with AD pathology and sex. The AD signature comprised profound alteration to RORB-GABRG excitatory neurons and disrupted oligodendrocyte precursor cell signaling. A separate set of AD-related cell-type specific molecular processes with strong sexual dimorphism also emerged. Importantly, these signatures developed and ROSMAP predicted neuropathology and sex, respectively, in a completely independent dataset (SEA-AD). These findings altogether summarize a highly consistent multi-cellular response to AD pathology in the human brain, creating a baseline cellular model to which perturbation and treatment experiments can be compared.

neuroscience↗

Shared and distinct immunometabolic states link to divergent pathology in cutaneous mycobacterial infections

Cutaneous mycobacterial infections provide a common tissue setting in which related intracellular pathogens elicit distinct pathological responses, but the innate immune basis of this divergence remains incompletely understood. Here, we combined single-cell profiling from 33 individuals with histological and functional analyses, examining healthy skin and lesions from multibacillary leprosy (MB), paucibacillary leprosy (PB), cutaneous tuberculosis (CTB) and Mycobacterium marinum infection (Mari). All infections showed lower mononuclear phagocyte and higher natural killer (NK) cell proportions within the CD45 compartment, alongside shared and infection-associated dendritic cell, macrophage and NK cell programs. CTB and Mari displayed broader macrophage antimicrobial signatures, whereas MB showed lipid-associated programs and attenuated interferon-associated effector expression across multiple macrophage subsets. Reduced expression of fructose-1,6-bisphosphatase 1 (FBP1) was associated with the absence of Langhans giant cells in MB, and pharmacological FBP1 inhibition nearly abolished fusion of macrophages. Compared with NK cells from Mari, MB NK cells showed reduced central carbon and oxidative metabolism signatures alongside increased lipid-associated programs. Functional experiments showed that inhibition of glucose utilization, disruption of mitochondrial function, or co-culture with foamy macrophages abundant in MB lesions reduced NK cell IFN-{gamma} production. These findings identify shared and distinct innate immune programs and suggest that their interplay with local metabolic environments shapes divergent pathology across cutaneous mycobacterial infections.

immunology↗

Fine-Grained and Reliable Cell Classification from Pathology Images

Molecular assays such as spatial transcriptomics facilitate fine-grained identification of cell types for analyzing tumor microenvironments. However, they are expensive to acquire in routine clinical practice compared to hematoxylin and eosin (H&E) images. With molecular guidance, such images can distinguish cell lineages, yet often fail to resolve closely related subtypes. To overcome this, we introduce CellBridge, a multi-modal contrastive learning framework pretrained on 16M cells with paired H&E and spatial profiles, for transferring molecular information into morphological representations. CellBridge further incorporates a Cell-Ontology-aware conformal prediction module that assigns labels at different levels of specificity: leaf-level cell types when morphology alone provides sufficient evidence, and broader ancestor categories when distinguishing among more specific cell types would require molecular information. Across in-domain and out-of-domain benchmarks, CellBridge outperforms leading pathology foundation models in macro F1 by up to 16 percentage points, with the largest gains on the most fine-grained label spaces. It consistently achieves smaller prediction sets, while reducing class-wise coverage gaps. We envision CellBridge as a step toward extracting cellular information that currently requires costly molecular assays from routinely acquired pathology images, while explicitly identifying where such assays remain necessary. Our code is available at https://github.com/Lotfollahi-lab/cellbridge.

bioinformatics↗

Design of readers for pathological PTM proteoforms in Alzheimer's disease

Alzheimer's disease (AD) is characterized by heterogeneous Tau phosphorylation and aberrant amyloid-beta (Abeta) processing, yet molecular tools that distinguish closely related molecular states of tau and Abeta with predefined specificity remain difficult to develop. Here, we designed de novo protein readers targeting three disease-associated phospho-Tau regions and N-terminal pyroglutamate-modified Abeta (N3pG-Abeta). Screening 192 designs per target identified 51 modification-selective hits among 768 candidates (6.6%). Representative readers exhibited nanomolar to subnanomolar affinities for modified peptides, discriminated authentic modifications from unmodified or substitution-based controls, and preferentially recognized modified full-length targets. We further programmed local modification specificity by interface redesign, generating pT231 readers conditional on the phosphorylation state of neighboring S235 and S237. A 2.0-angstrom crystal structure of an N3pG-Abeta reader closely matched the computational design model (interface C-alpha RMSD = 0.52 angstrom), and redesign of pT231 readers tuned apparent binding affinities from greater than 1 uM to below 1 nM. In a human 3D neuronal culture with both pathological Abeta and tau, selective readers targeting N3pG-Abeta, Tau pT231, and Tau pT217 recognized disease-associated signals, exhibiting colocalization with related antibodies and much higher signal in the AD line than the control. Tau pT231 readers further quantitatively distinguish AD patients and control human brain lysates in dot-blot assays. Together, these results establish genetically encoded readers with programmable specificity for defined Tau and Abeta modification states, enabling molecular-state-resolved detection in human disease models and biological samples, and lay a foundation for controlled pathological molecular perturbation.

bioengineering↗

Anti-GABAB receptor autoimmunity causes cognitive decline by presynaptic pathology

The GABAB receptor is a central regulator of neuronal transmission and excitability by pre- and postsynaptic mechanisms. Its dysfunction causes severe neurological disease, but the underlying pathomechanisms remain elusive. Here, we exploit a distinct CNS autoimmune disorder in which patients develop specific autoantibodies against GABAB receptors causing autoimmune encephalitis with severe memory dysfunction and epilepsy. We demonstrate that human autoantibodies target the sushi-domains of the GABAB receptor B1a subunit and the B2 subunit and interfere with presynaptic signaling. This specific presynaptic pathology results from exclusive functional antagonism of the B1a subunit and disrupts short- and long-term synaptic plasticity, abnormally amplifies hippocampal network oscillations and coupling in vivo, and ultimately impairs memory consolidation. Our results demonstrate that autoimmune presynaptic pathomechanisms alone are sufficient to interfere with memory processing, thus defining a causal link between molecular GABAB receptor disturbance, synaptic pathology, circuit dysfunction, and dementia distinct from classical neurodegenerative processes.

neuroscience↗

Cortical pyramidal tract neurons constrain pathological dopaminergic motor responses

Pyramidal tract (PT) neurons constitute a major cortical output pathway to subcortical structures, yet their contribution to parkinsonian and dyskinetic motor states remains unclear. Here, we show that chemogenetic activation of motor cortical PT neurons selectively confines pathological dopaminergic motor responses. Unilateral PT chemogenetic activation suppressed spontaneous locomotion in healthy mice but did not improve motor deficits following an ipsilateral 6-hydroxydopamine lesion. Instead, it attenuated contraversive rotations provoked by pharmacological D1-receptor stimulation and selectively reduced axial levodopa-induced dyskinesia. Mechanistically, PT stimulation reduced acute D1-mediated c-Fos induction in the dopamine-depleted striatum, without affecting chronic {Delta}FosB accumulation induced by repeated levodopa exposure. These findings identify a functional interaction between cortical PT output and striatal D1-receptor signalling that limits maladaptive motor responses to dopaminergic stimulation. Our results uncover a previously unrecognised cortical mechanism regulating pathological motor behaviour and suggest PT neurons as a potential substrate for circuit-based therapies in Parkinson's disease.

neuroscience↗