Biology subjects

Anikeeva, P.

Publications and source records attributed to Anikeeva, P..

16 recordsLinked to original sources

bioRxiv2026

Adrenal remodeling encodes stress axis memory to shape fentanyl seeking

The hypothalamic-pituitary-adrenal (HPA) axis is implicated in substance use disorders, yet the features of this circuit that contribute to addiction vulnerability remain unclear. Here, we show that fentanyl engages with different components of the HPA axis, and this engagement varies across timescales. Within minutes, fentanyl activated corticotropin-releasing hormone neurons in the paraventricular nucleus of the hypothalamus (PVNCRH) and transiently increased adrenocorticotropic hormone (ACTH) levels. Hours to days later, fentanyl suppressed PVN activity, reduced adrenal size, and impaired corticosterone release. Conversely, ACTH-induced adrenal hypertrophy, increased corticosterone, suppressed fentanyl-evoked PVNCRH activity, and elevated fentanyl-seeking behavior. These findings identify adrenal remodeling as a physiological record of stress history that shapes neuroendocrine and behavioral responses to fentanyl, mechanistically linking stress and addiction while revealing treatment targets for opioid dependence.

neuroscience↗

bioRxiv2026

Modelling prodromal Parkinson's disease- gastrointestinal pathology and early motor deficits in mice after transient rotenone exposure

Early gastrointestinal (GI) dysfunction is a hallmark feature of Parkinson's disease (PD), yet models capturing prodromal gut and brain pathology in PD remain limited. Motivated by the increased PD risk associated with pesticide exposure, we monitored motor behavior, brain pathology, and GI structure and function over 9 months following 5 daily doses of rotenone in mice. Transient rotenone exposure induced significant nigrostriatal pathology, including {approx}48% loss of dopaminergic neurons and increased -synuclein aggregation in the substantia nigra, without significant changes in gross motor function. Notably, we identified pronounced GI dysfunction including reduced colonic transit velocity, altered motility dynamics, and delayed whole-gut transit. These functional changes were accompanied by enteric dopaminergic neurodegeneration, increased colonic -synuclein accumulation, increased colonic crypt depth, goblet cell hyperplasia with elevated mucin content per goblet cell. The findings are consistent with prodromal PD, suggesting the utility of this model for investigating early disease mechanisms and intervention strategies.

neuroscience↗

bioRxiv2026

Attenuation of Inflammatory Cytokines by Selective Vagal Motor Stimulation via Silicone Spiral Nerve Cuff

ObjectivesTo determine how selective optogenetic vagus nerve stimulation (VNS) of distinct axonal subpopulations modulates systemic inflammatory cytokines in an acute model of endotoxemia. Materials and MethodsA silicone spiral nerve cuff with integrated custom probes including microscale light-emitting diodes (LEDs) was fabricated and implanted on the left cervical vagus nerve of anesthetized transgenic mice expressing ChR2 under cholinergic (ChAT) or glutamatergic (Vglut2) cell promoters. Lipopolysaccharide (3 mg/kg) was administered intraperitoneally to induce endotoxemia, and mice received optical VNS for 2 hours. Blood was collected 30 minutes after VNS termination and quantified via immunoassay for serum inflammatory cytokines (IL-6, IL-1{beta}, TNF-, IL-10) and C-reactive protein (CRP). ResultsChAT-selective optical VNS significantly reduced IL-6 (p = 0.027) and IL-1{beta} (p = 0.026) relative to Cre-negative sham controls. Vglut2-targeted stimulation did not significantly reduce IL-6, IL-1{beta}, or TNF- versus sham. Cytokine levels were significantly reduced with ChAT VNS compared to Vglut2 VNS in all pro-inflammatory cytokines (IL-6: p=0.024, IL-1{beta}: p=0.011, TNF-: p=0.030). The anti-inflammatory cytokine IL-10 was significantly decreased with ChAT versus Vglut2 VNS (p=0.033). CRP levels were not statistically different between groups. ConclusionsOptogenetic VNS targeting cholinergic neurons produced robust suppression of key pro-inflammatory cytokines IL-1{beta} and IL-6, whereas stimulation of glutamatergic neurons did not significantly alter inflammatory cytokine levels, highlighting the importance of pathway selectivity in the inflammatory effects of VNS. These findings highlight cell-type specific optogenetic neuromodulation as a valuable tool for assessing impact of vagal circuits and support preferential targeting of efferent cholinergic neurons in acute systemic inflammation.

bioengineering↗

bioRxiv2026

CHARIOT-AAV: Conjugation of diverse vectors to adeno-associated viruses for delivery of large genes

Systemic, tissue-specific delivery of large transgenes exceeding the packaging capacity of adeno-associated viruses (AAVs) remains a key translational challenge for molecular therapeutics. Vectors with larger capacities, such as lentiviral vectors (LVVs) and lipid nanoparticles (LNPs), often lack adjustable, tissue-specific tropisms. Here we report CHARIOT-AAV (Crosslinked Hybrid Architectures for Robust, Interchangeable, and Organ-specific Targeting with AAV), a platform where diverse delivery vectors are conjugated to AAVs, thereby achieving tissue-specific tropism of AAVs and expanded cargo capacity. AAV-AAV conjugates packaging split SpCas9 constructs in AAV.CAP-B10 capsids demonstrate a [~]2-fold increase in brain gene editing efficiency over unconjugated AAV cocktails after intravenous injection. In addition to AAV-AAV conjugates, AAV-LVV and AAV-LNP conjugates achieve AAV-guided delivery of genetic payloads to target cells. Furthermore, AAV-LNP conjugates enable systemic delivery of mRNAs to brain endothelial cells. CHARIOT-AAV thus provides a modular platform for systemic, tissue-specific delivery of diverse therapeutics beyond the limits of individual vectors.

bioengineering↗

bioRxiv2026

Wireless Magnetomechanical Stimulation of Targeted Vagal Gut-Brain Circuits

Causal manipulation of gut-brain neural circuits empowers studies of metabolism and interoception. However, the anatomy and cytoarchitecture of peripheral ganglia relaying gut-brain circuits pose challenges to deployment of optical or electrical stimulation probes. To enable implant-free, cell-type specific, and temporally precise control of defined gut-brain pathways, we develop a neuromodulation platform based on magnetic nanodiscs (MNDs) targeted to peripheral neurons via genetically delivered anchoring moieties. The anchored MNDs selectively transduce externally applied weak magnetic fields to mechanical torque, thereby activating endogenous mechanosensitive pathways in specified cell types with sub-second latency. When targeted to nodose ganglia neurons expressing oxytocin or glucagon-like peptide 1 receptors, MND-mediated stimulation enables robust and reversible activation of gut-brain signaling, which engages hindbrain satiety circuits and regulates feeding behavior. These findings establish MND-mediated stimulation as a genetically targetable, implant-free strategy for modulating gut-brain neural circuits and highlight its potential in studies of brain-body physiology and bioelectronic medicines.

bioengineering↗

bioRxiv2025

Stretchable thin-film metal electronics enabled by multilayered nanomembranes

Metallic thin films are indispensable in flexible electronics, yet their brittleness under tensile strain has impeded their use in intrinsically stretchable devices. Here, we overcome this barrier with a multilayer platform of alternating nanomembranes of metal and porous elastomer assembled via exponential stacking. The porous elastomer layers anchor adjacent metal layers and facilitate vertical percolation. Under strain, they dissipate stress and laterally misalign cracks within successive metal layers, forming crack-bridging conductive pathways. This architecture achieves synergistic scaling of electrical and mechanical performance with increasing layer number, demonstrating bulk-like conductance at strains exceeding 700% across a wide range of metals. Using nanomembrane stacks of gold and platinum, we fabricated stretchable electrode arrays that enabled high-fidelity recordings and electrical stimulation of murine colonic electrophysiology in vivo.

physiology↗

bioRxiv2025

Magnetoelectric nanodiscs diminish motor deficits in a model of Parkinson's disease

Magnetoelectric nanodiscs (MENDs) offer a wireless, minimally invasive route to neuromodulation by converting weak magnetic fields into electric polarization, but their therapeutic applications have remained unrealized. Here, we report the therapeutic development of MENDs for deep brain stimulation (DBS) in the subthalamic nucleus (STN) to alleviate motor deficits in a mouse model of Parkinsons disease. To quantitatively assess therapeutic outcomes, we introduce GaitPattern, a computational pipeline that extracts DBS-induced alterations in salient gait features. Using GaitPattern, we demonstrate that MEND-mediated STN DBS induces motor improvements with precision comparable to clinical electrode-based DBS, while minimizing inflammatory responses associated with the implanted hardware. Notably, MEND-mediated DBS reduces oxidative stress in the brain, a key contributor to neurodegeneration. These findings position MEND-mediated STN DBS as an effective and minimally invasive neuromodulation strategy.

neuroscience↗

bioRxiv2025

Adeno-associated viruses escort nanomaterials to specific cells and tissues

The delivery of nanotherapeutics to specific tissues relies on bespoke targeting strategies or invasive surgeries. Conversely, adeno-associated viruses (AAVs) can target specific tissues following intravenous injections. Here we show that cell-targeting properties of AAVs could be broadly conferred to nanomaterials. We develop a strategy to couple AAV capsids to nanoparticles that is invariant of viral serotype or nanomaterial chemistry and permits control over stoichiometry of the AAV-nanoparticle chimeras. The chimeras selectively escort nanoparticles into cell classes governed by AAV serotypes. When applied to magnetic nanoparticles, the AAV-nanoparticle chimeras enable magnetically localized gene delivery. In vivo, we show that leveraging the brain-targeting AAV serotype CAP-B10 achieves nanoparticle delivery to the parenchyma with [~]10% efficiency (% injected dose/g[brain]) while avoiding accumulation in the liver. The enhanced delivery efficiency and tissue specificity highlight the potential of AAV-chimeras as a versatile strategy to escort broad classes of nanotherapeutics to the brain and beyond.

bioengineering↗

bioRxiv2024

Fiber-based Probes for Electrophysiology, Photometry, Optical and Electrical Stimulation, Drug Delivery, and Fast-Scan Cyclic Voltammetry In Vivo

Recording and modulation of neuronal activity enables the study of brain function in health and disease. While translational neuroscience relies on electrical recording and modulation techniques, mechanistic studies in rodent models leverage genetic precision of optical methods, such as optogenetics and imaging of fluorescent indicators. In addition to electrical signal transduction, neurons produce and receive diverse chemical signals which motivate tools to probe and modulate neurochemistry. Although the past decade has delivered a wealth of technologies for electrophysiology, optogenetics, chemical sensing, and optical recording, combining these modalities within a single platform remains challenging. This work leverages materials selection and convergence fiber drawing to permit neural recording, electrical stimulation, optogenetics, fiber photometry, drug and gene delivery, and voltammetric recording of neurotransmitters within individual fibers. Composed of polymers and non-magnetic carbon-based conductors, these fibers are compatible with magnetic resonance imaging, enabling concurrent stimulation and whole-brain monitoring. Their utility is demonstrated in studies of the mesolimbic reward pathway by simultaneously interfacing with the ventral tegmental area and nucleus accumbens in mice and characterizing the neurophysiological effects of a stimulant drug. This study highlights the potential of these fibers to probe electrical, optical, and chemical signaling across multiple brain regions in both mechanistic and translational studies.

neuroscience↗

bioRxiv2023

Magnetoelectric Nanodiscs Enable Wireless Transgene-Free Neuromodulation

Deep-brain stimulation (DBS) with implanted electrodes revolutionized treatment of movement disorders and empowered neuroscience studies. Identifying less invasive alternatives to DBS may further extend its clinical and research applications. Nanomaterial-mediated transduction of magnetic fields into electric potentials offers an alternative to invasive DBS. Here, we synthesize magnetoelectric nanodiscs (MENDs) with a core-double shell Fe3O4-CoFe2O4-BaTiO3 architecture with efficient magnetoelectric coupling. We find robust responses to magnetic field stimulation in neurons decorated with MENDs at a density of 1 {micro}g/mm2 despite individual-particle potentials below the neuronal excitation threshold. We propose a model for repetitive subthreshold depolarization, which combined with cable theory, corroborates our findings in vitro and informs magnetoelectric stimulation in vivo. MENDs injected into the ventral tegmental area of genetically intact mice at concentrations of 1 mg/mL enable remote control of reward behavior, setting the stage for mechanistic optimization of magnetoelectric neuromodulation and inspiring its future applications in fundamental and translational neuroscience.

bioengineering↗

bioRxiv2022

Multifunctional fibers enable modulation of cortical and deep brain activity during cognitive behavior in macaques

Recording and modulating neural activity in vivo enables investigations of neural circuits during behavior. However, there is a dearth of tools for simultaneous recording and localized receptor modulation in large animal models. We address this limitation by translating multifunctional fiber-based neurotechnology previously only available for rodent studies to enable cortical and subcortical neural modulation in macaques. We record single unit and local field potential activity before, during, and after intracranial GABA infusions in the premotor cortex and putamen. We apply state-space models to characterize changes in neural activity and investigate how neural activity evoked by a working memory task varies in the presence of local inhibition. The recordings provide detailed insight into the electrophysiological effect of neurotransmitter receptor modulation in both cortical and subcortical structures in an awake, behaving macaque. Our results demonstrate a first-time translation of multifunctional fibers for causal studies in behaving non-human primates.

neuroscience↗

bioRxiv2022

Reprogramming brain immunosurveillance with engineered cytokines

Immune surveillance of the brain is regulated by resident non-neuronal cells and the blood-brain barrier.1 Dys-regulation of immunosurveillance is a hallmark feature of several diseases2-5 including brain tumors6 that interact with and rely heavily on immune cells,7 suggesting that disrupting the neuroimmunology of tumors could slow their progression. Yet few tools are available to control brain immunology in vivo with local precision, and fewer yet are used for therapeutic intervention. 2 Here, we propose engineered cytokines as a neuroimmune-modulation platform. We demonstrate that the residence time of cytokines in the brain can be tuned by binding them to the extracellular matrix or synthetic scaffolds. We then show that the aluminum hydroxide adjuvant (alum) is retained in the brain >2 weeks. Tethering of inflammatory cytokines such as interleukins (IL) 2 and 12 to alum yields extended neuroinflammation and brain immunosurveillance after intracranial administration, while avoiding systemic toxicity. In mouse models of both immunologically hot and cold brain tumors, the intracranial deposition of alum-tethered cytokines causes significant delay in tumor progression. RNA profiling reveals that engineered cytokines engage both innate and adaptive immunity in the brain. These findings suggest that engineered cytokines can reprogram brain immunosurveillance, informing the development of future therapies for neuroimmune diseases.

bioengineering↗

bioRxiv2021

Probing Neuro-Endocrine Interactions Through Wireless Magnetothermal Stimulation of Peripheral Organs

Exposure to stress alters hypothalamic-pituitary-adrenal (HPA) axis reactivity; however, it is unclear exactly how or where within the HPA pathway these changes occur. Dissecting these mechanisms requires tools to reliably probe HPA function, particularly the adrenal component, with temporal precision. We previously demonstrated magnetic nanoparticle (MNP) technology to remotely trigger adrenal hormone release by activating thermally sensitive ion channels. Here, we applied adrenal magnetothermal stimulation to probe stress-induced HPA axis changes. MNP and control nanoparticles were injected into the adrenal glands of outbred rats subjected to a tone-shock conditioning/extinction/recall paradigm. We measured MNP-triggered adrenal release before and after conditioning through physiologic (heart rate) and serum (epinephrine, corticosterone) markers. Aversive conditioning altered adrenal function, reducing corticosterone and blunting heart rate increases post-conditioning. MNP-based organ stimulation provides a novel approach to probing the function of HPA and other neuro-endocrine axes and could help elucidate changes across stress and disease models.

bioengineering↗

bioRxiv2021

Customizing Multifunctional Neural Interfaces through Thermal Drawing Process

Fiber drawing enables scalable fabrication of multifunctional flexible fibers that integrate electrical, optical and microfluidic modalities to record and modulate neural activity. Constraints on thermomechanical properties of materials, however, have prevented integrated drawing of metal electrodes with low-loss polymer waveguides for concurrent electrical recording and optical neuromodulation. Here we introduce two fabrication approaches: (1) an iterative thermal drawing with a soft, low melting temperature (Tm) metal indium, and (2) a metal convergence drawing with traditionally non-drawable high Tm metal tungsten. Both approaches deliver multifunctional flexible neural interfaces with low-impedance metallic electrodes and low-loss waveguides, capable of recording optically-evoked and spontaneous neural activity in mice over several weeks. We couple these fibers with a light-weight mechanical microdrive (1g) that enables depth-specific interrogation of neural circuits in mice following chronic implantation. Finally, we demonstrate the compatibility of these fibers with magnetic resonance imaging (MRI) and apply them to visualize the delivery of chemical payloads through the integrated channels in real time. Together, these advances expand the domains of application of the fiber-based neural probes in neuroscience and neuroengineering.

neuroscience↗

bioRxiv2020

In vivo photopharmacology enabled by multifunctional fibers

To reversibly manipulate neural circuits with increased spatial and temporal control, photoswitchable ligands can add an optical switch to a target receptor or signaling cascade. This approach, termed photopharmacology, has been enabling to molecular neuroscience, however, its application to behavioral experiments has been impeded by a lack of integrated hardware capable of delivering both light and compounds to deep brain regions in moving subjects. Here, we devise a hybrid photochemical genetic approach to target neurons using a photoswitchable agonist of capsaicin receptor (TRPV1), red-AzCA-4. Using the thermal drawing process we created multifunctional fibers that can deliver viruses, photoswitchable ligands, and light to deep brain regions in awake, freely moving mice. We implanted our fibers into the ventral tegmental area (VTA), a midbrain hub of the mesolimbic pathway, and used them to deliver a transgene coding for TRPV1. This sensitized excitatory VTA neurons to red-AzCA-4, and allowed us to optically control conditioned place preference using a mammalian ion-channel, thus extending applications of photopharmacology to behavioral experiments. Applied to endogenous receptors, our approach may accelerate studies of molecular mechanisms underlying animal behavior.

neuroscience↗

bioRxiv2020

A gut sensor for sugar preference

Summary Paragraph/AbstractAnimals innately prefer caloric sugars over non-caloric sweeteners. Such preference depends on the sugar entering the intestine.1-4 Although the brain is aware of the stimulus within seconds,5-8 how the gut discerns the caloric sugar to guide choice is unknown. Recently, we discovered an intestinal transducer, known as the neuropod cell.9,10 This cell synapses with the vagus to inform the brain about glucose in the gut in milliseconds.10 Here, we demonstrate that neuropod cells distinguish a caloric sugar from a non-caloric sweetener using the electrogenic sodium glucose co-transporter 1 (SGLT1) or sweet taste receptors. Activation of neuropod cells by non-caloric sucralose leads to ATP release, whereas the entry of caloric sucrose via SGLT1 stimulates glutamate release. To interrogate the contribution of the neuropod cell to sugar preference, we developed a method to record animal preferences in real time while using optogenetics to silence or excite neuropod cells. We discovered that silencing these cells, or blocking their glutamatergic signaling, renders the animals unable to recognize the caloric sugar. And, exciting neuropod cells leads the animal to consume the non-caloric sweetener as if it were caloric. By transducing the precise identity of the stimuli entering the gut, neuropod cells guide an animals internal preference toward the caloric sugar.

neuroscience↗