Biology subjects

Singh, T.

Publications and source records attributed to Singh, T..

At least 19 recordsLinked to original sources

bioRxiv2026

Male Age and Sexual Maturity: Lipopolysaccharide-induced tumor necrosis factor influences sperm quality and reproduction in Anopheles culicifacies

Elucidating the biological and molecular mechanisms that govern male fertility and mating behavior in mosquitoes is critical for optimizing genetic and sterile insect technique-based vector control strategies. Here, we examined age-related changes in male reproductive capacity in Anopheles culicifacies, using female egg output as an indirect indicator of male fertility. Our results demonstrated that male reproductive age follows a non-linear pattern of fertility. Morphometric analysis from emergence to day 13 post-eclosion revealed a strong correlation between seminal vesicle capacity and female fecundity, suggesting that age-dependent gonadal development directly influences reproductive potential. At the molecular level, we identified AcLITAF6 as a key regulator of male reproductive homeostasis. RNAi-mediated knockdown of AcLITAF6 impaired apoptosis-associated and phagocytic clearance, reduced sperm viability, and decreased female productive outcomes. Conclusively, we reveal a previously unrecognized role of LITAF in sperm quality control and male reproductive fitness, highlighting AcLITAF6 as a potential target for mosquito population suppression strategies.

developmental biology↗

bioRxiv2026

Current challenges in GWAS integration and fine-mapping for variant interpretation

Over the past two decades, genome-wide association studies (GWAS) have identified thousands of trait- and disease-associated loci. However, the mechanistic understanding of these loci remains incomplete, which limits our ability to understand gene regulation and cellular programs underlying complex traits, predict disease risk, and develop therapeutics targeted to root causes. Here, we describe the current challenges for using GWAS to prioritize variants for functional follow-up experiments. These challenges span multiple domains, including limitations in data sharing and harmonization, limitations of statistical and functional fine-mapping, and the ambiguity in the added value of emerging deep learning frameworks for variant effect prediction as a complementary approach alongside traditional statistical genetics methods. We analyze these variant prioritization methods and suggest a multi-modal approach for resolving GWAS loci to a focused set of high-confidence variants for functional exploration. Fully realizing the potential of GWAS will require harmonized summary statistics and broader sharing of in-sample linkage disequilibrium (LD) data to enable robust and scalable causal variant prioritization.

genetics↗

bioRxiv2026

Adaptation to postural perturbations under fatigue produces persistent changes in neuromuscular coordination

Postural control depends on the ability to adapt motor responses to changing environmental and physiological conditions. Neuromuscular fatigue (NMF) is known to alter balance and muscle activation patterns, yet its effects on motor adaptation during whole-body postural tasks and on the persistence of learned strategies remain unclear. This study investigated whether localized NMF of the ankle dorsiflexors influences adaptation to a novel postural perturbation task and whether learning under fatigue induces persistent changes during subsequent re-exposure. Twenty-five healthy young adults were assigned to either a fatigue or no-fatigue group and completed two experimental sessions separated by 48-72 h allowing recovery from acute fatigue for fatigued group. Participants adapted to repeated mechanical perturbations while standing upright, while ground reaction forces and electromyographic activity of lower-limb muscles were recorded. NMF did not impair overall adaptation performance, as both groups exhibited similar reductions in performance error across practice. However, participants exposed to fatigue exhibited altered postural recovery dynamics, characterized by a reduced return toward the initial posture following perturbation release. These differences persisted during re-exposure on the subsequent day, despite the absence of acute fatigue. In parallel, NMF modified muscle activation and coactivation patterns involving both fatigued and non-fatigued muscles, several of which were retained during re-exposure. These findings indicate that the central nervous system preserves successful adaptation to postural perturbations under fatigue by reorganizing neuromuscular coordination and stabilization strategies. Learning under fatigue therefore influences not only immediate motor execution, but also shapes the next-session persistence of postural control strategies.

neuroscience↗

bioRxiv2026

Senataxin loss induces cGAS–STING-mediated mitochondrial dysfunction

Ataxia with oculomotor apraxia type 2 (AOA2) is a rare neurodegenerative disease caused by loss-of-function mutations in Senataxin, which encodes an RNA:DNA helicase. Many studies on Senataxin loss focus on its putative roles in regulating transcription and RNA transcript localization. However, several phenotypes remain underexplored, including metabolic dysregulation associated with ataxias. Using Senataxin-deficient mouse cells, we observed increased nuclear and genomic instability, as well as innate immune activation via the cGAS-STING axis. We also observed elevated ROS levels, decreased mitochondrial function, and hyperfused mitochondria. Importantly, mitochondrial dysfunction depends on cGAS/STING activity, indicating that the two phenotypes are functionally connected. Senataxin-deficient mice and AOA2 patient cells similarly exhibit spontaneous innate immune activation, and AOA2 patient cells also show decreased mitochondrial function. Our work identifies a previously unseen phenotype for AOA2 in which loss of Senataxin results in mitochondrial dysfunction promoted by cGAS and STING. SummaryThis study demonstrates a previously unidentified phenotype in AOA2 and Senataxin research in which cGAS-STING promotes mitochondrial dysregulation in Setx-/- MEFs. Further, these innate immune activation and mitochondrial dysregulated phenotypes are recapitulated in AOA2 patient cells.

Cell Biology↗

bioRxiv2026

Bright Probes, Blurred Metabolism: Navigating Fluorescent Protein Cross-Excitation in NADH FLIM

Fluorescence lifetime imaging microscopy (FLIM) of endogenous NAD(P)H enables the label-free assessment of cellular metabolic state. Although metabolic imaging is increasingly combined with fluorescent protein (FP) reporters to enhance biological specificity, the potential cross-talk between the intrinsic and extrinsic labels remain ill-defined. Here, we systematically evaluate cross-talk from FPs in metabolic FLIM using phasor analysis of two-photon fluorescence microscopy. The results clearly show that many widely used fluorescent proteins are excited under the conditions used for NADH imaging; they emit blue-shifted, short-lifetime fluorescence that can interfere with imaging NADH metabolic signatures. This overlap persists across excitation wavelengths and FP classes, posing a significant challenge for multiplexed metabolic imaging. This cautionary tale argues against unvalidated multiplexing strategies in metabolic FLIM studies. Our study aims to identify acceptable imaging partners, offer a pipeline for assaying potential cross-talk, and provide practical guidance for experimental design. SignificanceFluorescence lifetime imaging of NADH autofluorescence is a powerful, label-free approach to map cellular metabolism in living tissues. A growing number of studies combine NADH imaging with fluorescent protein (FP) reporters to simultaneously identify specific cell types or subcellular compartments. This study reveals that many FPs, spanning the visible spectrum, are unexpectedly excited under NADH conditions. Commonly used green, yellow, and red variants produce short-lifetime, blue-shifted fluorescence that directly overlaps with metabolic NADH signals. This cross-excitation can be falsely interpreted as a shift in cellular metabolic state, posing a significant risk for multiplexed metabolic imaging studies. Our studies establish a pipeline to assess and manage this risk. We identify StayGoldE138D and mNeonGreen as the most compatible FPs for co-imaging with NADH, and provide a practical framework to guide experimental design and control strategies for multiplexed metabolic FLIM.

biophysics↗

bioRxiv2026

Phosphorus-laden Mg/Fe Layered Double Hydroxide Dispersed on Douglas fir Biochar as a Controlled Release Fertilizer and its effect on the growth of bush beans (Phaseolus vurlagris).

Many agricultural soils are deficient in key macronutrients needed for healthy plant development. Relying on highly water-soluble commercial fertilizers for long durations can be costly and environmentally harmful. This study investigates a phosphorus-loaded Mg/Fe layered double hydroxide (LDH) dispersed on Douglas fir biochar (Mg/Fe-LDH biochar) as a controlled-release fertilizer and evaluates its impact on bush bean (Phaseolus vulgaris L.) growth. Emphasizing sustainability, the work integrates controlled-release fertilizers, biochar, and LDH modification to enhance nutrient use efficiency and mitigate environmental runoff. Mg/Fe-LDH was directly synthesized on biochar via a co-precipitation approach, loaded the composite with phosphate by anion exchange, and characterized the material using elemental analysis, N2 Brunauer-Emmett-Teller (BET) determinations surface area analysis, and x-ray photoelectron spectroscopy to confirm successful LDH modification on Douglas fir biochar, and high surface area with accessible active sites. The synthesis yielded a stable P-Mg/Fe-LDH biochar with enhanced dispersibility and phosphate-buffering capacity, enabling controlled-release fertilization. In greenhouse experiments, bush beans grown with the P-Mg/Fe-LDH biochar exhibited improved growth metrics, including increased yield (beans fresh weight of 31.7 g), biomass (plant dry weight of 6.3 g), plant height (32.8 cm), and improved nutrient uptakes (1.88 mg (P) g-1) at 100.88 kg (P2O5) ha-1 compared with unfertilized controls and conventional P fertilizers, indicating efficient, controlled-release phosphate delivery and sustained nutrient availability. The results demonstrate that integrating LDH-modified biochar can enhance P uptake and plant growth while reducing leaching losses. Overall, this study highlights the strategic significance of combining biochar, layered double hydroxides, and controlled-release formulations to advance sustainable nutrient management and improve crop performance in agroecosystems. The findings offer a promising pathway for environmentally conscious fertilizer design and soil amendment strategies that align with global goals for resource efficiency and food security. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=110 SRC="FIGDIR/small/727001v1_ufig1.gif" ALT="Figure 1"> View larger version (48K): org.highwire.dtl.DTLVardef@2ab2aforg.highwire.dtl.DTLVardef@139014corg.highwire.dtl.DTLVardef@1842c62org.highwire.dtl.DTLVardef@7e0b06_HPS_FORMAT_FIGEXP M_FIG C_FIG

plant biology↗

bioRxiv2026

Aging selectively impairs how peripheral vision calibrates anticipatory postural responses to object motion

Anticipatory postural adjustments (APAs) scale with velocity of approaching objects, with scaling magnitude depending on whether the moving object is actively foveated and tracked, processed through fixated peripheral vision, or processed through fixated central vision. Aging preferentially degrades the magnocellular pathway underlying peripheral motion processing while sparing the extraretinal signals available during smooth pursuit. We therefore asked whether the effect of aging on velocity-dependent APA scaling differs across these three visual pathways. Eighteen young and eighteen older adults stopped a virtual object approaching at four velocities (15-33 cm/s) under three gaze conditions: active foveation via smooth pursuit, central fixation, and peripheral fixation. We measured peak anticipatory force, rate of force development, and time to contact at force onset. Despite reduced smooth pursuit gain in older adults, velocity-dependent scaling was equivalent between age groups during active foveation, and minimal in both groups during central fixation. Critically, young adults scaled force rate during peripheral fixation nearly as steeply as during active foveation, whereas older adults slope was significantly lower -- a difference not observed during the other gaze conditions. Older adults achieved comparable peak force by initiating responses earlier. These results establish that age-related decline in anticipatory motor control is pathway-specific: aging selectively impairs peripheral motion processing for APAs, while extraretinal mechanisms remain capable of sustaining velocity-dependent scaling. More broadly, peripheral motion processing emerges as a candidate physiological locus of age-related postural vulnerability, raising the question of whether magnocellular-targeted training can restore APA scaling in older adults. Key PointsO_LIYoung and older adults stopped virtual objects under three visual conditions: active foveation via smooth pursuit eye movements, and stationary gaze with the object moving through either central or peripheral vision. C_LIO_LIVelocity-dependent force rate scaling was preserved during active foveation in both age groups, minimal during fixated central vision in both age groups, and selectively impaired in older adults during fixated peripheral vision. C_LIO_LIWe found an age-induced vulnerability in peripheral visual motion processing for anticipatory posture stabilization. C_LI

neuroscience↗

bioRxiv2026

XRRA1 acts as a molecular brake on radiation-induced DNA damage signaling and immunogenic cell death in tumor cells.

Radiotherapy kills cancer cells by inducing DNA damage, but adaptive responses that buffer injury and limit immunogenic signaling remain incompletely understood. Although ionizing radiation can activate cytosolic DNA sensing and immunogenic cell death, the tumor-intrinsic regulators linking these processes to radioresistance are not well defined. Here, we show that XRRA1 is a stress-adaptive determinant of radioresponse identified by integrating discovery proteomics into chronic myeloid leukemia with clinical tissue validation and functional studies across multiple tumor models. In peripheral-blood proteomes, XRRA1 was quantitatively reduced in chronic myeloid leukemia yet associated with a favorable prognosis and with networks enriched for RNA regulation, apoptosis, and DNA-repair biology. In human biopsy specimens, XRRA1 protein abundance was increased in radiation-exposed tissues, and in cultured cells, ionizing radiation induced XRRA1 more strongly and persistently in normal cells than in cancer cells. Silencing XRRA1 had little effect on basal growth but markedly enhanced radiation-induced loss of viability, apoptosis, spheroid disruption, and clonogenic failure, while increasing {gamma}H2AX- and DNA-PK-associated damage signaling and linking XRRA1 to non-homologous end joining factors. XRRA1 depletion also amplified cGAS-STING-TBK1-IRF3 activation, interferon-stimulated gene expression, extracellular ATP release, and cell-surface calreticulin exposure. These findings identify XRRA1 as a molecular brake that limits the conversion of radiation-induced DNA damage into immunogenic stress responses. XRRA1, therefore, represents a candidate biomarker of radioadaptive stress and a potential target for radiosensitization and radiotherapy-immunotherapy combinations.

cancer biology↗

bioRxiv2026

Disruption of PI3K/OxPhos Coupling by Trehalose Drives a BCAA to Lipid Metabolic Switch in Hormone Receptor Positive Breast Cancer

Cancer cells sustain proliferation through dynamic coordination between mitochondrial oxidative phosphorylation (OxPhos) and anabolic carbon metabolism. How this metabolic coupling can be selectively destabilized in subtype-specific contexts remains poorly defined. Here we identify trehalose, a disaccharide previously linked to autophagy modulation, as a regulator of mitochondrial-anabolic integration in breast cancer. Using high-resolution respirometry, untargeted metabolomics, and signalling analyses across estrogen/progesterone receptor-positive (ER) and triple-negative models, we show that trehalose preferentially impairs mitochondrial bioenergetics in OxPhos-dependent ER cells. Trehalose reduced electron transport system capacity, NADH-linked respiration, mitochondrial membrane potential, and coupling efficiency, while suppressing mitochondrial biogenesis markers. These bioenergetic effects coincided with attenuation of PI3K/Akt signalling and induction of p21-associated growth arrest. Metabolomic profiling revealed a coordinated redistribution of carbon flux characterized by depletion of branched-chain amino acids (BCAAs) and glycolytic intermediates alongside accumulation of long-chain fatty acids and cholesterol. Correlation network analysis uncovered a strong inverse relationship between BCAA-linked metabolism and lipid abundance, indicating a regulated metabolic trade-off rather than nonspecific stress. Functionally, trehalose enhanced the efficacy of mitochondrial-interfering agents such as tamoxifen and colchicine, while exerting minimal effects in metabolically flexible triple-negative cells. Together, these findings define trehalose as a metabolic modulator that constrains mitochondrial plasticity and enforces a lipid-buffered, growth-restrictive state in ER breast cancer, revealing a therapeutic vulnerability linked to mitochondrial dependency.

cancer biology↗

bioRxiv2026

Dengue virus-specific memory B cell subsets differ as a function of infection history

The four dengue virus serotypes (DENV1-4) are a major global health threat. Infection generates protective immunity over multiple exposures with different serotypes. Virus-specific memory B cells (MBCs) can contribute to lasting protection, yet their development over multiple DENV infections remains undefined. We comprehensively evaluated frequencies of nine DENV-specific B cell subsets in 58 samples from dengue cases, comparing groups with primary (1{degrees}) versus secondary (2{degrees}) DENV infection history. Longitudinal sampling from acute infection to 18 months post-symptom onset enabled assessment of DENV-specific MBC temporal dynamics. Critically, we found that DENV-specific B cell frequency differed substantially at the level of phenotypic subsets in 1{degrees} versus 2{degrees} immunity, despite no significant difference in total frequency of DENV-specific B cells. In particular, DENV-specific IgG+, IgM+, atypical, and class-switched IgD-MBCs were durable until 18 months and accumulated with multiple exposures, representing a bona fide memory compartment against DENV. Also, naive-like IgD+/IgM+ DENV-specific B cells were found. Interestingly, the peak of certain DENV-specific MBCs occurred >3-months post-symptom onset in 2{degrees} DENV immunity, suggesting potential for long-term MBC maturation. We demonstrate that DENV-specific MBC subsets differ as a function of infection history, suggesting that 2{degrees} DENV immunity does not simply generate a quantitative boost, but a qualitative reprogramming of the memory pool. Significance StatementThe four dengue virus serotypes (DENV1-4) cause the most prevalent human mosquito-borne viral disease. Dengue is a febrile disease that often results in debilitating body pain and can rapidly progress to severe disease involving shock. People are generally protected after multiple exposures to different serotypes. Memory B cells (MBCs) can contribute to lasting protection against subsequent dengue. To understand how these rare DENV-specific MBCs develop over multiple exposures, we compared samples from cases with primary versus secondary (i.e., multiple) DENV infections. We found that instead of a higher frequency of total DENV-specific MBCs, particular subsets of DENV-specific MBCs were higher and peaked later after multiple exposures. This suggests that a qualitative shift in DENV-specific MBCs may contribute to protective immunity.

immunology↗

bioRxiv2026

How Visual Context Influences Lateral Stepping Regulation While Walking on Winding Paths

Goal-directed walking involves regulating foot placements to achieve specific tasks. This requires visuomotor integration. Perceptual, cognitive, and contextual salience guide attention and motor planning for navigation. Here, we quantified how perceptual salience informs lateral foot placement while walking. Participants walked along prescribed virtual paths (straight or winding), thus keeping contextual salience (the task itself) constant. We manipulated perceptual salience by systematically altering environment richness (rich vs. sparse) and path color contrast (high vs. low). We thus tested the extent to which stepping control is determined only by the walking path (i.e. its shape), or is also influenced by task-relevant salience of the paths (only), and/or the salience of the surrounding environment. We quantified head pitch angle to approximate gaze direction. We quantified lateral stepping regulation from a Goal Equivalent Manifold framework. On winding (vs. straight) paths, participants looked down more (lower mean head pitch) and more consistently (less variable head pitch). They took narrower, more variable steps and corrected stepping errors more strongly. This confirmed the predominant influence of task (contextual salience) on stepping control. On low (vs. high) contrast paths, participants looked down more and exhibited greater variability in lateral position on their path with weaker error correction. Higher contrast paths elicited stronger and more consistent stepping control. Walking in sparse (vs. rich) environments yielded somewhat less consistent, but still significant changes in head pitch and stepping regulation. Salience manipulations affected stepping differently on straight versus winding paths. Therefore, perceptual salience influences step-to-step control during naturalistic walking.

neuroscience↗

bioRxiv2026

Visual Context Influences Lateral Balance While Walking on Winding Paths

Effectively navigating daily environments necessitates achieving adaptability while maintaining stability. This requires integrating sensory feedback, primarily from the visual system, to maintain balance and maneuverability as we walk. This study examined the impact of visual information salience on lateral balance and stepping. Twenty-eight healthy adults (16F/12M; 26.16{+/-}4.23 years) participated. Participants walked along each of two virtual paths (Straight vs. Winding), having each of two path color contrasts (High vs. Low), in each of two environments with differing visual richness (Rich vs. Sparse). We quantified stepping errors as the percentage of steps landing outside designated path boundaries. We computed means () and standard deviations ({sigma}) of the minimum mediolateral margins of stability (MoSL), and we computed lateral Probability of Instability (PoIL) to assess participants risk of taking unstable (MoSL < 0) steps. On Straight paths, participants made more stepping errors on Low (vs. High) contrast paths for both environments, and exhibited decreased{sigma} (MoSL) in Sparse (vs. Rich) environments on paths of both visual contrasts. On Winding paths, participants made the most stepping errors on Low Contrast paths in Sparse environments. They walked with smaller (MoSL) and exhibited higher PoIL on Low Contrast paths in both environments, and they exhibited higher PoIL in Sparse environments on paths of both visual contrasts. The effects of diminished visual information were far more pronounced on Winding paths (vs. Straight), hindering performance and balance maintenance, as these conditions challenged both mechanical and sensory mechanisms underlying balance control.

neuroscience↗

bioRxiv2025

Sexual dimorphism in zymosan-induced arthritis is linked with a higher IFN response in myeloid cell subsets that faithfully recapitulate RA synovial cell clusters

A key feature of rheumatoid arthritis (RA) is sexual dimorphism, with a higher incidence of RA in females. Myeloid cells are key drivers of the inflammatory effector phase of RA, but little is known about their contribution to a sexually dimorphic arthritis phenotype. We wished to utilize an arthritis model that recapitulates RA pathogenic myeloid cell subsets defined by single cell transcriptome analysis to investigate sex differences in human disease-relevant cell types and related molecular pathways. We developed a computational strategy that rigorously maps scRNAseq-defined mouse arthritis myeloid cells and clusters onto previously defined RA subsets. Synovial myeloid cells in the zymosan-induced arthritis (ZIA) model closely recapitulated four pathogenic RA myeloid cell subsets, strongly supporting the disease-relevance of the ZIA model. ZIA also effectively modeled myeloid cells in immune checkpoint inhibitor arthritis (ICI-A). These RA, ICI-A and ZIA myeloid cells express genes in TNF-NF-kB, PGE2, and IFN-STAT pathways. In ZIA, an induction phase dominated by cell clusters expressing NF-kB and PGE2 pathways transitioned to peak arthritis characterized by cell subsets co-expressing NF-kB and IFN pathways, as occurs in RA and various inflammatory diseases. Female mice exhibited increased arthritis linked with early induction of interferon-stimulated genes and increased expansion of IFN signature-expressing cell subsets. Our study identifies a computational strategy and animal model that enables investigation of recently described pathogenic myeloid cell subsets, and links increased arthritis in female mice with specific myeloid cell subsets that exhibit a stronger IFN response.

immunology↗

bioRxiv2025

DIET IMPACTS THE EFFECTS OF THERMAL STRESS ON INFECTION OUTCOMES

BackgroundClimate change can lead to warmer environments, facilitating higher pathogen growth and increasing disease burden. Climate change can also reduce the nutritional value of food resources, causing malnutrition, which can lead to impaired immunity and disease vulnerability. However, despite these associations, no experiments have tested how dietary manipulations and temperature variations interact to drive the effects of pathogenic infections. In this work, we conducted laboratory experiments with the model insect Drosophila melanogaster to test these effects. ResultsVirgin flies raised on low-carbohydrate diets exhibited improved post-infection survival rates and more resilience to pathogen burden compared to those reared on standard or high-carbohydrate diets. However, such a survival advantage of the low-carbohydrate diet was lost in mated individuals. Notably, temperature stress decreased survival rates in flies only when they were reared on a standard diet. This effect was not observed in flies raised on high- or low-carbohydrate diets, indicating that the impact of temperature on infection responses might depend on diet. Besides, flies developing on a low-carbohydrate diet showed greater fertility at ambient temperatures than those on other diets, indicating an apparent lack of fitness costs associated with improved post-infection response. Also, high-carbohydrate diets conferred greater resistance to starvation, suggesting differences in resource allocation among somatic maintenance tasks that could increase vulnerability to pathogens. ConclusionOverall, these findings imply a complex interaction between diet, temperature, and fitness traits that influences variation in infection responses. As many organisms around the world face environmental warming and poor diets, examining these patterns and processes can provide a deeper understanding of variations in health and disease responses amid a changing climate.

ecology↗

bioRxiv2025

Cerebrovascular response dynamics to hypercapnia in healthy aging

Cerebrovascular dysfunction is an early and underrecognized contributor to cognitive decline. Standard measures such as cerebrovascular reactivity (CVR) during hypercapnia capture only the amplitude of flow responses, providing limited insight into the timing of vascular adaptation. Temporal features, such as delay (onset latency) and time constant (rate of adjustment), together with gain (response amplitude) may serve as more sensitive indicators of vascular health, but cannot be directly obtained from conventional imaging. Here, we investigated cerebral blood flow (CBF), cerebral blood volume (CBV), and blood oxygenation level dependent (BOLD) signal dynamics during hypercapnic challenge in healthy aging. Using a physiologically validated computational model, we estimated delay, time constant, and gain by optimizing the mapping of end-tidal gases to their arterial counterparts in a region-of-interest framework. Once parametrized using CBF, the model successfully predicted CBV and BOLD responses in independent experimental sessions. Across subjects, aging was associated with widespread heterogeneous region-specific changes in delay and substantial reductions in gain and time constant, indicating that cerebrovascular responses become weaker and less adaptable with age. These results demonstrate that calibrated simulations have the ability to track vascular aging, allowing the extraction of parameters that may represent novel biomarkers of cerebrovascular dysfunction. Unlike conventional CVR, temporal hemodynamic parameters capture the dynamics of vascular adaptation, providing a complementary dimension for early detection and therapeutic monitoring in aging and disease.

neuroscience↗

bioRxiv2025

Non-neuronal signal fluctuations in Alzheimer's disease and in mild cognitive impairment

Blood oxygenation level dependent (BOLD) functional magnetic resonance imaging (fMRI) permits the investigation neural activity thanks to the neurovascular coupling mechanism. However, neural activity accounts for only a portion of the observed BOLD signal fluctuations, as the vasculature integrates multiple physiological inputs that contribute to the response. Research focusing on isolating the vascular components of the BOLD signal revealed that markers of cerebrovascular health, such as cerebrovascular reactivity (CVR), serve as valuable biomarkers for neurodegenerative diseases. This study examines the relationship between vascular metrics and noise in a cohort comprising individuals with Alzheimers disease (AD), mild cognitive impairment (MCI), and healthy controls (HC). Vascular responses were assessed using three functional contrasts during a hypercapnic challenge: arterial spin labeling (ASL) to measure cerebral blood flow (CBF) reactivity, vascular space occupancy (VASO) to quantify cerebral blood volume (CBV) reactivity, and BOLD imaging. Noise metrics were derived from multi-echo BOLD resting-state data by isolating the TE-independent components of the signal. Mean correlation coefficients for noise vs ASL-CVR are: (-0.12 {+/-} 0.06) for HC, (-0.14 {+/-} 0.08) for MCI, (-0.11 {+/-} 0.05) for AD. Mean correlation coefficients for noise vs BOLD-CVR are: (0.25 {+/-} 0.11) for HC, (0.24 {+/-} 0.07) for MCI, (0.23 {+/-} 0.11) for AD. Mean correlation coefficients for noise vs VASO-CVR are: (0.13 {+/-} 0.10) for HC, (0.13 {+/-} 0.07) for MCI, (0.12 {+/-} 0.12) for AD. These results suggest that TE-independent noise relates to the three vascular contrasts to varying extents and directions, with no significant differences across groups. Further analysis within specific functional networks revealed group differences in specific networks. The observed cortical correlations between noise and vascular features provide important insights into brain function and the progression of neurodegenerative diseases, offering a potential avenue to disentangle vascular and neural contributions in brain network and connectivity studies.

neuroscience↗

bioRxiv2025

Peripheral Neuropathy After Chronic Alcohol Exposure in Mice: Impact of sex, total intake and duration and alcohol metabolism.

Alcohol induced peripheral neuropathy (AIPN) is a neurodegenerative disease caused by chronic alcohol intake and is associated with peripheral nerve damage and somatosensory symptoms, such as allodynia. Current treatments lack efficacy and do not target underlying pathology emphasizing the need for preclinical models of AIPN to elucidate mechanisms and novel targets. Thus, we performed a detailed characterization of a mouse model of AIPN and candidate mechanistic associations including the role of neuroinflammation and acetaldehyde. Our studies showed chronic alcohol induced mechanical and cold hypersensitivity and deficits in spontaneous behaviors in EtOH concentration-, time- and sex-dependent manners. Female mice drank more alcohol and developed more rapid and severe hypersensitivity but less robust deficits of spontaneous behaviors. The grimace test demonstrated chronic alcohol promoted spontaneous pain independent of sex. Duration of intake impacted alcohol-induced deficits in peripheral nerve electrophysiology amplitude and intra-epidermal nerve fiber density. We characterized an extensive time-course of chronic alcohol-induced neuroinflammation in the DRG and spinal cord and found significant time, sex and tissue effects. Polymorphisms of ALDH2 have been associated with alcohol-induced neuroinflammation, alcohol-related pain, and alcohol-induced peripheral neuropathy. We investigated the role of acetaldehyde, via inhibition of ALDH2, in the development of AIPN and showed that ALDH2 inhibition accelerated and exacerbated development of chronic alcohol-induced hypersensitivity in male and female mice. Overall, our studies in a well-controlled model of AIPN strongly point to neuroinflammation and inflammatory modulators such as acetaldehyde as important mechanistic targets for possible intervention in AIPN.

pharmacology and toxicology↗

bioRxiv2025

Genetics-to-structure multiscale analysis identifies disrupted calcium homeostasis as a mechanism of psychiatric disease

Neuropsychiatric disorders are highly heritable, but the molecular mechanisms linking risk variants to disease remain unclear1. Linking genetics to biological mechanisms requires integrating evidence across scales, from sequence variation to gene regulation to protein function. Here we integrate genetic, transcriptomic, and structural evidence to identify dysregulation of neuronal Ca2+ dynamics as a contributing mechanism. We analyzed single-nucleus neuronal RNA-seq data together with genome-wide association study (GWAS) heritability in a new way to identify gene expression programs enriched for psychiatric risk; genes encoding Ca2+ flux pathway genes were implicated by this analysis, a result that was then confirmed by concentrations of rare coding variants in these same genes in persons with psychiatric disorders. A critical gene in this biology, ATP2B2, encodes a Ca2+-extruding ATPase pump2 linked to neuropsychiatric disorders primarily through missense variants. To recognize specific molecular functions affected by these missense variants, we developed a 3D-neighborhood-based method that maps missense variants onto AlphaFold3-predicted protein structures and tests clustering of protein-altering variants in three-dimensional space. This approach revealed clustering of these missense changes in the Ca2+ pore and ATP:Mg2+ coordination site of ATP2B2. To validate the structural predictions arising from the genetic analysis, we determined the structure of human Ca2+-bound ATP2B2 at 2.64 [A] resolution by cryogenic electron microscopy. The structure replicated the 3D mutational hotspots identified by the genetic analysis, supporting the observation that neuropsychiatric variants cluster near specific catalytic sites of ATP2B2. In vitro experiments revealed that missense variants prioritized by the structural clustering analysis impaired ATP2B2-mediated Ca2+ extrusion in cellular and biochemical assays. Together, these findings suggest that precise regulation of Ca2+ dynamics is a contributing mechanism in neuropsychiatric disorders and establish a structure-based framework for predicting the mechanistic impact of missense variants.

genetics↗