Biology subjects

Kaur, G.

Publications and source records attributed to Kaur, G..

At least 19 recordsLinked to original sources

bioRxiv2026

A male-specific neural circuit for appetitive thirst in Drosophila

Thirst is the brain representation of the need to restore water balance. While environmental and interoceptive sensory neurons that assess water availability and status are known, the central brain representation of thirst that determines behavior in Drosophila is less well understood. We identified a male-specific appetitive thirst circuit in Drosophila using circuit mapping, connectomics, and behavior measurements. Male-specific NPF-M neurons receive thirsty seeking information via Allatostatin A (AstA) neuropeptide released from the Janu-AstA projection neuron. In turn, NPF-M neurons release the neuropeptides sNPF, NPF, and DH31 to promote thirsty water seeking and the neurotransmitter acetylcholine to inhibit it. NPF-M neurons regulate multiple motivated behaviors, including appetitive and consummatory thirst, food foraging, and courtship, driven by distinct input neurons. NPF-M neurons output to appetitive and aversive dopaminergic, mushroom body ongoing behavior integration center, and navigation circuits. This circuit exhibits similarities to those for hungry food foraging and courtship. NPF-M and Janu-AstA form a network with OviIN hub neurons that are sex-independent thirst neurons. We suggest that NPF-M neurons form a circuit branch that funnels male-specific information to tune motivated behavior.

neuroscience↗

bioRxiv2026

Frequency-Domain Analysis Links Autonomic Disruption to Renal Autoregulatory Failure after Spinal Cord Injury

Spinal cord injury (SCI) disrupts supraspinal autonomic pathways that regulate cardiovascular function, producing marked blood pressure instability and contributing to secondary injury in peripheral organs. The kidney is particularly vulnerable to these disturbances because renal blood flow (RBF) depends on tightly regulated interactions between neural, myogenic, and vascular control mechanisms. However, how SCI level and chronicity alter dynamic renal autoregulation remains poorly defined. Here, we investigated the effects of high- and low-thoracic SCI on renal hemodynamic control using in vivo blood pressure and RBF recordings in female mice. Hemodynamics were assessed at baseline and during acute sympathetic stimulation induced by norepinephrine (NE; 10 {micro}g/kg, i.v.) at 24 h and 4 wk following spinal cord transection at thoracic level 3 (T3) or thoracic level 10 (T10). Time-domain analyses quantified systolic blood pressure recovery, while frequency-domain analyses were used to resolve myogenic and sympathetic contributions to RBF regulation. High-thoracic SCI caused marked disruption of renal vascular responses to acute hypertension, producing paradoxical increases in RBF during NE-induced pressure elevations and sustained reductions in baseline and evoked RBF activity within frequency ranges associated with myogenic and sympathetic vasomotion. These impairments were most pronounced during the chronic phase of injury, consistent with loss of dynamic autoregulatory control and vascular remodeling. In contrast, low-thoracic SCI preserved baseline renal vasomotor activity and demonstrated recovery of dynamic autoregulatory responses over time. These findings identify SCI level and chronicity as critical determinants of renal microvascular regulation and demonstrate that high-thoracic SCI produces persistent autonomic-vascular uncoupling. This disruption of dynamic renal autoregulation represents a previously underappreciated mechanism of secondary organ vulnerability following neurotrauma. VISUAL ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=109 SRC="FIGDIR/small/735393v1_ufig1.gif" ALT="Figure 1"> View larger version (58K): org.highwire.dtl.DTLVardef@3c8452org.highwire.dtl.DTLVardef@11358f4org.highwire.dtl.DTLVardef@1352ae9org.highwire.dtl.DTLVardef@1943807_HPS_FORMAT_FIGEXP M_FIG C_FIG New & NoteworthyThis study introduces a frequency-domain analytical framework to quantify dynamic renal blood flow regulation after spinal cord injury (SCI). By resolving myogenic and sympathetic vasomotor activity across physiologically relevant frequency bands, we reveal that high-thoracic SCI causes a sustained, broadband loss of renal vasomotion and impaired autoregulatory responses to acute hypertension. In contrast, low-thoracic SCI preserves baseline spectral activity and permits recovery over time. This approach provides a mechanistic link between autonomic disruption and renal vascular dysfunction following SCI.

physiology↗

bioRxiv2026

Neuraminidase1 Activity Contributes to Vasopressin Receptor-mediated Augmentation of Water and Electrolyte Retention by the Kidney in Eln Haploinsufficient Mice

Elastin haploinsufficiency is a primary determinant of arteriopathy and hypertension that hallmark Williams syndrome (WS), a rare genetic disorder resulting from microdeletion of genes on human chromosome 7, including the elastin gene (ELN). Accumulating evidence suggests renal dysfunction, including enhanced sodium and water retention as an underlying cause of blood pressure elevation resulting from heterozygous deletion of Eln (Eln+/-) in mice that recapitulates the cardiovascular phenotype of WS. However, the underlying pathophysiological mechanisms are poorly understood. Here, we determined whether the activity of neuraminidase-1 (NEU1) of the elastin receptor complex (ERC) contributes to abnormal handling of water and electrolytes by the kidney in Eln haploinsufficiency. Adult male and female Eln+/+ and Eln+/- mice were subjected to acute extracellular fluid volume expansion with normal saline, combined with pharmacological intervention targeting vasopressin V2 receptor (V2R), NEU1, ENaC, and NKCC2. In male Eln+/+ mice, V2R blockade induced a dose-dependent increase in urine flow rate without affecting sodium excretion. Conversely, V2R stimulation with desmopressin markedly increased urinary sodium excretion in male Eln+/+ but not Eln+/- mice, while both sexes of Eln+/- mice exhibited marked suppression of urine flow rate. Abrogation of ERC signaling through NEU1 inhibition produced a modest increase in urinary sodium excretion in male mice of both genotypes but augmented urine flow rate only in male Eln+/+mice. NEU1 blockade strikingly enhanced the natriuretic effect of furosemide and amiloride in male Eln+/+ and modestly in Eln+/-mice. Taken together, we conclude that Eln haploinsufficiency disrupts vasopressin-dependent modulation of sodium and water reabsorption by sex-dependently altering ERC-mediated modulation of NKCC2 and ENaC. These findings reveal a novel mechanism by which abnormal ERC activity due to Eln haploinsufficiency potentially contributes to renal dysfunction and hypertension. GRAPHICAL ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=120 SRC="FIGDIR/small/731713v1_ufig1.gif" ALT="Figure 1"> View larger version (50K): org.highwire.dtl.DTLVardef@13264fdorg.highwire.dtl.DTLVardef@18453fforg.highwire.dtl.DTLVardef@a6c17eorg.highwire.dtl.DTLVardef@1e9564d_HPS_FORMAT_FIGEXP M_FIG C_FIG AC, adenylyl cyclase; AQP2, aquaporin 2; CD, collecting duct; CNT, connecting tubule; DCT, distal convoluted tubule; EBP, elastin binding protein; Eln, elastin allele; ENaC, epithelial sodium channel; ERC, elastin receptor complex; Gs, stimulatory G subunit; NEU1, neuroaminidase1; NKCC2, sodium-potassium-chloride cotransporter; PPCA, protective protein/ cathepsin A; TAL, loop of Henle thick ascending limb; V2R, vasopressin receptor type 2

physiology↗

bioRxiv2026

Single-cell learning in Stentor coeruleus is governed by a fractional-order low-pass filter

Single cells display a range of complex behaviors normally associated with a nervous system, including basic forms of learning like habituation. The giant ciliate Stentor coeruleus habituates to mechanical stimuli and shows many of the hallmark features characteristic of habituation in animal cells. When Stentor cells are mechanically stimulated by a predator or other stimuli, an action potential fires and leads to calcium-dependent contraction. When the same cell is repeatedly stimulated, it becomes less likely to respond, thus showing habituation. While the molecular basis of habituation in Stentor is not yet known, it has been shown to involve CaMKII, which also plays a key role in learning in neurons. The presence of an action potential, the role of calcium in the response, and the involvement of CaMKII in habituation, all suggest a potential deep conservation of learning mechanisms between single-celled protists and the neurons of animals. A number of different models have been proposed to explain habituation in a single cell but existing data in Stentor are unable to clearly rule out any of these models or favor others. Here we report a frequency domain analysis of habituation in which we measure the response probability of Stentor cells to pulsatile stimuli delivered at a range of frequencies. We find that the Bode plot of the frequency response resembles a classic low pass filter, with a flat passband at low frequencies, a clear corner frequency, and a linear roll-off. However, unlike standard low pass filter, the roll-off occurs with a slope of -30dB/decade, thus showing a fractional-order behavior. None of the existing models for habituation in Stentor, at least in their current form, predict this form of the frequency response, leading us to look for other explanations. We tested, and ruled out, a model based on a refractory period associated with the re-extension of cells following contraction. Inspired by methods used in analog circuit design to approximate fractional order systems using conventional lumped devices, we developed a model in which a series of distinct molecular species, such as different multimeric complexes of CaMKII, acting in parallel to inhibit the response, produce a fractional-order effect. The fractional order behavior of habituation in Stentor resembles the fractional-order behavior of adaptation in neurons, further supporting the idea that neurons may employ similar mechanisms for learning as were already present in unicellular eukaryotes prior to the evolution of metazoa.

cell biology↗

bioRxiv2026

Antioxidant properties of Rhodiola rosea

Rhodiola rosea is a traditional medicinal plant often classified as an adaptogen, with reported effects in supporting the bodys response to physical, environmental, and emotional stressors. The present study investigated the antioxidant properties of Rhodiola rosea extract and its major chemical constituents to provide insight into their potential mechanisms of action. Through in vitro biochemical assays, we demonstrated that Rhodiola rosea extract has the capacity to reduce hydrogen peroxide (H2O2) levels. Among its primary chemical components, rosavin significantly decreased H2O2, whereas salidroside had no effect. Neither compound affected superoxide levels. Structural analysis revealed that the intact phenylpropanoid glycoside architecture of rosavin is required for activity, as its individual components, arabinose and rosin, showed no inhibitory effect. Further investigation demonstrated that rosavin attenuates H2O2-mediated oxidation of thiol groups, supporting a role in cellular redox regulation. In cultured human cells, rosavin mitigated reductions in cell viability induced by exposure to H2O2, indicating cytoprotective effects under oxidative stress conditions. Finally, in an in vivo model, administration of SARS-CoV-2 spike protein increased circulating levels of H2O2, which were subsequently reduced following rosavin treatment. Collectively, these findings identify rosavin as a structurally dependent antioxidant component of Rhodiola rosea that modulates H2O2-associated oxidative stress and supports further investigation of phenylpropanoid glycosides as adaptogens.

biochemistry↗

bioRxiv2026

Nuclear blebs are composed of variable chromatin states but consistently enrich transcription initiation relative to elongation

Nuclear blebs are herniations of the nucleus that occur in many human conditions including aging, heart disease, muscular dystrophy, and many cancers. Nuclear blebbing causes nuclear rupture and cellular dysfunction. However, understanding the formation, stability, and identification of nuclear blebs remains an ongoing challenge. Our previous studies reveal that nuclear blebs are best hallmarked by decreased DNA density. To determine if chromatin decompaction underlies decreased DNA density in nuclear blebs, we investigated the histone composition of nuclear blebs across multiple cell lines. Time lapse and immunofluorescence imaging revealed that global histone H2B and H3 levels are decreased in the nuclear bleb relative to the nuclear body. Next, we imaged histone modification states of euchromatin and heterochromatin, which respectively track decompact and compact states of chromatin. Overall, we find that nuclear blebs display variable histone modification state across cell lines, as euchromatin does not consistently enrich nor is heterochromatin consistently depleted. Nuclear blebs did consistently show active RNA Pol II initiation is enriched relative to elongation. Thus, we find that the local histone modification state is not an essential component of nuclear blebs while transcription initiation enrichment over elongation is reproducible across cell lines and conditions. Summary statementWe measured histones and their modification states in nuclear blebs. We find that chromatin state is variable while transcription initiation is consistently enriched relative to elongation in nuclear blebs.

cell biology↗

bioRxiv2026

Phylogeny and morphology of novel Labyrinthulomycetes in Nova Scotia, Canada

Labyrinthulomycetes are ubiquitous marine decomposers and include the thraustochytrids, a lineage known for their extensive production of polyunsaturated fatty acids and biotechnology applications. Despite historical taxonomic confusion, environmental surveys have begun to expand the known diversity within labyrinthulomycetes. Here we present 18S ribosomal DNA (rDNA) sequences from 17 novel labyrinthulomycetes strains established as axenic cultures from natural samples taken from three locations in Nova Scotia, Canada. We also present light and transmission electron microscopic analysis for three of these isolates. The combination of phylogenetic and morphological analysis suggests that these isolates belong to three different genera, Thraustochytrium, Ulkenia and Oblongichytrium. Our results expand the known genetic diversity of labyrinthulomycetes in Atlantic Canadian waters, contributing new strains to understudied genera for future comparative genomic investigations, including Ulkenia and Oblongichytrium for which very few genomic resources are available.

evolutionary biology↗

bioRxiv2025

Modeling the phage properties best for therapy

The phages used to treat bacterial infections in phage therapy are commonly chosen based on their abilities to form plaques on the infecting bacterium - on host range. In practice, phage therapy is not always successful, leaving room for improvement. Here we use computational models to investigate whether some standard phage properties (burst size, lysis, adsorption, decay rate, growth rate) might serve as predictors of treatment success. As our measure of treatment success, we deviate from many other approaches by calculating the number of phage needed to suppress bacterial densities 100-fold in the short term, given that the patients immune system is expected to regain control once bacterial numbers are reduced. Numerical analysis of 2400 combinations of different values of phage phenotypes reveals that, on average, adsorption rate and growth rate provide the most useful predictive values, decay rate provides some value, whereas burst size and lysis time offer essentially little or no value. Bacterial density is especially informative of the number of phage required for treatment. There is nonetheless often considerable variation around average behavior for a single phenotype. These results raise the possibility that adsorption rate and growth rate may be especially important in phage therapy performance for both high and low bacterial densities. Given that therapeutic phages are often evolved in vitro for broad host ranges rather than for individual hosts, it should be considered that selection for broad host range may have a downside of compromising adsorption to and growth rate on individual bacterial hosts.

microbiology↗

bioRxiv2025

Structure of human lymphoid-specific helicase HELLS in its autoinhibitory state

Helicase, Lymphoid Specific (HELLS), also known as Lymphoid-Specific Helicase (LSH), is a member of the SNF2 chromatin-remodeling family that regulates DNA methylation and heterochromatin organization. Unlike most chromatin remodelers, HELLS is catalytically inactive in its apo form and requires the DNA-binding protein CDCA7 for activation, though the underlying mechanism has remained unclear. Here, we combine biochemical, biophysical and cryo-electron microscopy analyses to define the structural basis of HELLS autoinhibition. HELLS alone assembles into a hexameric (trimer of dimers) architecture stabilized by interactions between its N-terminal coiled-coil (CC) domain and ATPase Lobe-1, while ATPase Lobe-2 remains flexible and disengaged. The CC domain functions both as an oligomerization scaffold and as an autoinhibitory module that restricts catalytic activity. Binding of CDCA7 and DNA promotes formation of an active HELLS-CDCA7-DNA ternary complex. CDCA7 recognizes hemimethylated CpG dinucleotides in both B-form and non-B-form DNA and stimulates HELLS ATPase activity. Together, these findings reveal the mechanism of HELLS autoinhibition and its activation by CDCA7 and DNA, providing new insight into how the HELLS-CDCA7-DNA ternary complex maintains DNA methylation and heterochromatin integrity. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=78 SRC="FIGDIR/small/692698v1_ufig1.gif" ALT="Figure 1"> View larger version (26K): org.highwire.dtl.DTLVardef@106b73borg.highwire.dtl.DTLVardef@1e7b33aorg.highwire.dtl.DTLVardef@a7be6eorg.highwire.dtl.DTLVardef@c75a5b_HPS_FORMAT_FIGEXP M_FIG C_FIG O_LIHELLS alone assembles into an inactive hexameric trimer-of-dimers C_LIO_LIThe N-terminal coiled-coil mediates oligomerization C_LIO_LICDCA7 and DNA binding activate the HELLS-CDCA7-DNA complex C_LIO_LIThe complex recognizes hemimethylated CpG in non-B-form DNA C_LI

molecular biology↗

bioRxiv2025

Deposition of microplastics associated with bioaccumulation of heavy metals in human lungs of smokers: Implications of adsorption and mobilization of metals via microplastics

BackgroundAirborne micro- and nano plastics (MNPs), generated from synthetic textiles, vehicle tires and plastic wastes, are omnipresent in the environment and known to deposit in human lungs. Bioaccumulation of MNPs in lung tissues has been studied, but effect of tobacco smoking on deposition is not well understood. Tobacco smoke is known to contain heavy metals which can get adsorbed to the MNP surface, leading to increased environmental bioavailability. We hypothesized that smoking leads to enhanced chelation of heavy metals with airborne MNPs leading to accentuated lung bioaccumulation, thereby leading to lung pathologies. MethodsAge (20-75 years) and sex-matched archival lung tissue samples from smokers (n = 9) and non-smokers (n = 10) were procured and quantified to assess: (a) the levels of MNPs by pyro-GC/MS and (b) heavy metals by ICP-MS. Furthermore, to establish if there exists a correlation between MNP deposition and disease occurrence in current smokers, tissue samples from age-matched patients with COPD (n = 4) and IPF (n = 4) underwent pyro-GC/MS analyses. ResultsA relatively higher level of MNPs were found in the lungs of smokers (43.67 mcg/gm) as compared to non-smoker (34.53 mcg/gm) upon pyro-GC/MS analyses. We observed a marked increase in the levels of polyethylene (PE; p< 0.0076), polycarbonate (PC; p< 0.0947) and nylon6 (N6; p < 0.0653) polymers in the lungs of smokers as compared to non-smokers. Metal analyses showed a significant (p <0.0001) increase in the levels of cadmium (Cd) in the lungs of smokers with the levels of deposited Cd being more pronounced for female smokers. Importantly, we observed a strong correlation (p < 0.05) between the amounts of accumulated PE and levels of Cd in the lungs. Pyro-GC/MS analyses did not reveal any relation between MNP deposition and disease occurrence in our study. Furthermore, little to no change in the level of deposited MNPs was observed in the lungs of current versus ex-smokers in disease cohorts. ConclusionsOverall, our results show that smoking promotes bioaccumulation of certain MNPs (PE) with heavy metals (Cd) which may lead to adverse lung effects in smokers.

pharmacology and toxicology↗

bioRxiv2025

Ovarian Hormones Moderate Hypertension in Female Eln Haploinsufficient Mice

Hypertension is a hallmark of cardiovascular abnormalities associated with Williams syndrome (WS), a rare genetic disorder involving microdeletion of genes on human chromosome 7, including the elastin gene (ELN). Heterozygous deletion of Eln (Eln+/-) in mice recapitulates hypertension and arteriopathy associated with WS. Previously, differences in blood pressure elevation and sensitivity to dietary sodium were found to be less profound in female Eln+/- mice. Here, we determined whether ovarian hormones play a role in sex-related difference in blood pressure elevation resulting from Eln haploinsufficiency. Female Eln+/+ and Eln+/- mice instrumented with radiotelemetry devices were subjected to sham surgery or ovariectomy (OVX). We found that OVX lowered diastolic but not systolic blood pressure (SBP) in Eln+/- mice, resulting in increased pulse pressure. In Eln+/- mice, diuresis induced by acute volume expansion was blunted, while anti-natriuresis was exaggerated. Furthermore, amiloride lowered SBP and increased urinary Na+ excretion, suggesting that Eln+/--induced hypertension may be Na+-dependent. We conclude that increased Na+ and water retention by the kidney contribute to hypertension resulting from Eln haploinsufficiency. The underlying mechanism involves the alteration of ovarian hormone effects in the kidney and sustained signaling downstream of the V2 receptor, leading to increased ENaC activity and water reabsorption. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=103 SRC="FIGDIR/small/689164v1_ufig1.gif" ALT="Figure 1"> View larger version (15K): org.highwire.dtl.DTLVardef@1ccfa15org.highwire.dtl.DTLVardef@369344org.highwire.dtl.DTLVardef@fe8194org.highwire.dtl.DTLVardef@ed285d_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOGraphical AbstractC_FLOATNO CDPC, cortical duct principal cell; ER, estrogen receptor; PR, progesterone receptor; ENaC, epithelial sodium channel; AQP2, aquaporin 2; V2R, vasopressin V2 receptor; ELN, elastin; PKA, protein kinase A; AC, adenylyl cyclase; Gs, stimulatory G protein; ATP, Adenosine triphosphate; cAMP, cyclic AMP; {oplus}, activating; {ominus}, inhibiting C_FIG

physiology↗

bioRxiv2025

Modeling Asthma Burden in India Using Physics-Informed Neural Networks with Time-Varying Parameters Driven by Pollution Dynamics

Asthma is a chronic respiratory condition exacerbated by environmental pollution, particularly in rapidly urbanizing regions such as India. Accurate modeling of asthma dynamics in response to pollution is challenging due to the presence of un-measured, time-varying parameters. In this study, we develop a seven-compartment asthma-pollution model incorporating susceptible, carrier, exposed, undiagnosed infected, diagnosed infected, recovered, and pollutant burden compartments. We employ a physics-informed neural network (PINN) framework to infer the hidden temporal profiles of key parameters, including the pollution-driven transmission rate ({xi}(t)), environmental progression rate ({lambda}1(t)), pollutant accumulation rate (A(t)), and pollutant depletion rate ({tau}t(t)), from synthetically generated noisy data. The PINN approach integrates the compartmental ODE system via a fourth-order Runge-Kutta solver and minimizes a combined loss function capturing both state fidelity and parameter consistency. Evaluation of model performance demonstrates excellent agreement with ground-truth trajectories, achieving mean squared errors below 10-4 for all compartments and sub-2% deviation for inferred parameters. These results highlight the utility of PINNs for reverse function discovery in complex epidemiological systems and provide a framework for quantitatively linking environmental pollution to asthma burden in settings with limited observational data.

bioinformatics↗

bioRxiv2025

Alzheimer's disease risk factor APOE4 exerts dimorphic effects on female bone

Individuals diagnosed with Alzheimers disease (AD) are at an increased risk of bone fractures. Conversely, a diagnosis of osteoporosis in women is the earliest known predictor for AD. However, mechanisms responsible for the coupled decline in cognitive and skeletal health remain unclear. Proteomic analysis of cortical bone from aged mice revealed neurological disease-associated proteins that are highly enriched in aged mouse bones, including apolipoprotein E (Apoe) and amyloid precursor protein. Further, Apoe localized specifically to bone-embedded osteocytes with expression twice as high in aged female bone as in young or male counterparts. In humans, APOE allele variants carry differing AD risk with age. To investigate APOE allelic roles in bone, we utilized a humanized APOE knock-in mouse model that expresses either the protective APOE2, the neutral APOE3, or the AD risk factor APOE4, and analyzed bone and hippocampus from the same mice. APOE4 exerted strong sex-specific effects on the bone transcriptome and proteome, relative to APOE2 or APOE3. Interestingly, the APOE4-associated perturbation in the female bone proteome was more pronounced than the corresponding alterations observed in the hippocampus. APOE4 protein causes bone fragility in females, but not males, even without changes in cortical bone structure. These bone quality deficits arose from suppression of osteocyte perilacunocanalicular remodeling. We find that APOE4 is a new molecular culprit capable of disrupting osteocyte maintenance of bone quality as early as midlife in a manner that disproportionately affects females. These findings highlight osteocytes as potential targets for early diagnosis of age-related cognitive impairment, and treatment for bone fragility, in females.

molecular biology↗

bioRxiv2025

TRIM62 promotes lipid raft-mediated entry of influenza A virus by regulating WASH localization

Viruses employ diverse strategies to gain entry into cells to reach their replication sites. Influenza A virus (IAV), a respiratory pathogen, takes advantage of clathrin-dependent endocytosis or macropinocytosis for its internalization. Here, we report that TRIM62, a member of the tripartite motif (TRIM) protein family, is required for IAV entry, independent of its E3 ubiquitin ligase activity. We find that TRIM62 specifically functions in a clathrin-independent, lipid raft-mediated pathway, which IAV exploits to enter the endocytic network. Additionally, we reveal the involvement of the WASH complex and the retromer component VPS35 in this pathway beyond their canonical functions in endosomal sorting. We observe that a pool of WASH and VPS35 localize to the plasma membrane and associate with lipid rafts, in addition to their typical endosomal presence. While WASH subunits except FAM21 play a proviral role in IAV endocytosis and intracellular trafficking, VPS35 acts antagonistically. We show that TRIM62 counteracts the antiviral function of VPS35 by limiting FAM21-VPS35 interaction. By directly binding WASH in the cytosol, TRIM62 restricts its VPS35-mediated endosomal recruitment and thereby enhances its surface availability to facilitate IAV entry. Together, this study uncovers previously unrecognized roles of TRIM62 and endosomal sorting machinery in IAV entry, offering new antiviral targets.

cell biology↗

bioRxiv2025

Immunologic insights into the critical epitopes of HIV-1 and structure-based characterization of cross-reactive antibodies

HIV-1 escape from neutralizing antibodies even in the presence of strong host immunity is associated with variations in envelope proteins that drive antigenic diversification. The virus exploits the error-prone nature of reverse transcriptase and the high mutation rate as key survival strategies. However, the rate of production of new variations occurs at relatively slow pace. Interestingly, the immune system often produces cross-reactive antibodies, with anticipated role in neutralizing point mutations in HIV surface proteins by cross-reacting with mutants and tolerating them. In light of this paradox, we explored the mystery of immune evasion and antibody promiscuity by screening single chain variable fragment (scFvs) antibodies against several crucial HIV-1 gp41 epitopes using a phage display library. These findings underscore the broader significance of cross-reactive antibodies. Here, high-affinity cross-reactive scFvs showed physiologically relevant affinities with peptide epitopes, their analogs, and the native HIV-1 gp41 protein. We determined the crystal structure of a high-affinity cross-reactive scFv, DE94, and obtained insights into the molecular interactions of scFv antibodies with peptide epitopes and its natural mutants using molecular docking studies. This analysis of cross-reactive antibodies could contribute to the therapeutic development against immune-evading pathogens and paves the way for innovative strategies for combating viral infections, including emerging global threats.

biophysics↗

bioRxiv2025

A single NPFR neuropeptide F receptor neuron that regulates thirst behaviors in Drosophila

Thirst is a strongly motivated internal state that is represented in central brain circuits that are only partially understood. Water seeking is a discrete step of the thirst behavioral sequence that is amenable to uncovering the mechanisms for motivational properties such as goal-oriented behavior, value encoding, and behavioral competition. In Drosophila water seeking is regulated by the NPY-like neuropeptide NPF, however the circuitry for NPF-dependent water seeking is unknown. To uncover the downstream circuitry, we identified the NPF receptor NPFR and the neurons it is expressed in as being acutely critical for thirsty water seeking. Refinement of the NPFR pattern uncovered a role for a single neuron, the L1-l, in promoting thirsty water seeking. The L1-l neuron increases its activity in thirsty flies and is involved in the regulation of dopaminergic neurons in long-term memory formation. Thus, NPFR and its ligand NPF, already known for its role in feeding behavior, are also important for a second ingestive behavior. Significance StatementUnderstanding how a single motivated behavior is represented in the neural circuitry of the brain will help uncover drive-specific and universal encoding mechanisms for motivation. Thirst is useful because it is relatively simple compared to feeding behavior and it is strongly motivated. The fly Drosophila, with its straightforward genetics and complete connectome, is helpful in determining a complete circuit for thirsty water seeking. Here we discover a single neuron in the fly brain, the L1-l, that actively receives input from the NPY-like neuropeptide NPF to promote water seeking. Prior findings suggest that the L1-l modulates valence inputs into sensory processing centers, suggesting a similar function in thirsty seeking. Visual Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=135 SRC="FIGDIR/small/662850v1_ufig1.gif" ALT="Figure 1"> View larger version (70K): org.highwire.dtl.DTLVardef@685da2org.highwire.dtl.DTLVardef@1db60f2org.highwire.dtl.DTLVardef@1b9d1a5org.highwire.dtl.DTLVardef@72bd09_HPS_FORMAT_FIGEXP M_FIG C_FIG

neuroscience↗

bioRxiv2025

Overcoming host restrictions to enable continuous passaging of human noroviruses in human intestinal enteroids

Human noroviruses (HuNoVs), the leading cause of viral gastroenteritis, can now be cultivated in human intestinal enteroids (HIEs). However, indefinite passaging of HuNoVs in HIEs remained a challenge, necessitating the use of patient stool samples as viral inocula. Using RNA-seq, we identified host restriction factors that might limit viral passaging. CXCL10, CXCL11, and CCL5 were among the most upregulated chemokines, suggesting their potential as host restriction factors. TAK-779, a CXCR3/CCR5/CCR2 antagonist, enhanced GII.3 HuNoV replication and viral spread in a dose- and time-dependent manner, enabling successful passaging of GII.3 HuNoV in two different HIE lines and generation of viral stocks. TAK-779 also enhanced replication of GI.1 and GII.17 strains, but not GII.4, suggesting strain-specific host interactions or immune evasion. This breakthrough in passaging provides critical insight into HuNoV-host interactions, establishes a scalable in vitro system for virus propagation, and opens avenues for structural, biochemical and therapeutic studies.

microbiology↗

bioRxiv2025

Proteomic profiling of primary cilia in the developing brain uncovers newregulators of cortical development

In the developing brain, the primary cilia of radial glial cells extend from the surface of the lateral ventricle, serving as the signaling hub to integrate environmental cues critical for brain formation. Dysfunctions in ciliary proteins contribute to a wide range of brain structural abnormalities in ciliopathies, yet identifying the bona fide ciliary protein components in the brain remains a significant challenge. Here, using proximity labeling and quantitative proteomics, we systematically charted proteins localized to the cilia of radial glial cells in the dorsal and ventral regions of the embryonic brain. From this dataset, we identified cohorts of new molecules intrinsic to the cilia at distinct regions of the developing brain. We validated the cilium localization of several components of the translation machinery and studied the mechanistic roles of ciliary candidates previously linked to brain malformation, including Marcks, a key regulator of radial glial polarity, and Ckap2l, a protein associated with Filippi syndrome. These results revealed previously unrecognized ciliary mechanisms that regulate brain development. Thus, our brain proteomic dataset provides a unique resource for understanding ciliary functions in brain development and the molecular etiology of developmental disorders.

developmental biology↗