Biology subjects

Singamaneni, S.

Publications and source records attributed to Singamaneni, S..

9 recordsLinked to original sources

bioRxiv2026

Hyperexcitable but seizure-free: hippocampal network dysfunction in a Wolfram syndrome model

Wolfram syndrome (WS) is a rare, life-limiting progressive neurodegenerative disorder caused by pathogenic variants in the WFS1 gene. It is a prototype endoplasmic reticulum (ER) stress disorder, and the mechanisms underlying neurological phenotypes in WS remain incompletely understood. Although WFS1 protein is abundant in the hippocampus, the role of this region in WS remains relatively understudied. Here we characterize hippocampal function across scales in mice carrying a patient orthologous Wfs1 variant (p.W542*) on both alleles. Male mutants lose excitatory synapses, and dissociated hippocampal neurons are markedly hyperexcitable yet generate no increase in network bursting and no shift in network criticality, indicating that their additional firing is not recruited into coordinated population activity. This finding translates in vivo wherein intracranial electroencephalogram (EEG) recordings show no epileptiform activity or seizures in either sex, with no hippocampal astrogliosis, alongside a male-specific reduction in hippocampal low-gamma power. Additionally, EEG demonstrates a sex-specific disruption of sleep, which parallels a sex-divergent synaptic phenotype. Mutant male mice show impaired hippocampus-dependent fear memory and reduced voluntary motor activity. Taken together, we propose that cellular hyperexcitability in the WS hippocampus does not translate into increased network bursting, potentially due to disproportionate loss of excitatory synapses. This dissociation may provide a functional substrate for the neurological features of WS.

neuroscience↗

bioRxiv2026

Palmitoylation calibrates mitochondrial transport of insulin across the endothelium in insulin resistance

Impaired insulin transport across the endothelium contributes to insulin resistance, a poorly understood condition implicated in diabetes and many other chronic diseases. Insulin has been reported to undergo non-receptor-mediated endocytosis resembling fluid-phase uptake through unclear mechanisms. Here we show in mice with diet-induced insulin resistance that endothelial-specific deletion of the depalmitoylase acyl-protein thioesterase 1 (APT1) improved glucose tolerance and insulin sensitivity without affecting chronic inflammation or capillary structure. Endothelial APT1 deficiency increased interstitial insulin levels in mice confirmed by in-situ microneedle-based sampling. In cultured human microvascular cells, APT1 inhibition enhanced cell transport of high-dose insulin independent of the insulin receptor and canonical endocytic machinery. Unexpectedly, live-cell imaging revealed insulin rapidly localizing to mitochondria prior to endolysosomal trafficking, even at physiological insulin concentrations. APT1 inhibition delayed mitochondrial discharge of insulin to lysosomes. Cyclosporin A, an immunosuppressant known to affect mitochondrial function, preserved mitochondrial insulin content and promoted insulin transport in cultured cells, and enhanced interstitial insulin delivery in mice. Proteomic analysis revealed two palmitoylated proteins, PACS1 and YTHDF2, required for APT1-mediated mitochondrial-endolysosomal trafficking of insulin. A mitochondrial insulin shuttle in endothelial cells may participate in the physiological adaptation to hyperinsulinemia and its regulation by palmitoylation suggests a novel approach to insulin resistance.

physiology↗

bioRxiv2026

MANF Clears Mutant Uromodulin in Human Kidney Organoids of Autosomal Dominant Tubulointerstitial Kidney Disease

Autosomal dominant tubulointerstitial kidney disease due to uromodulin mutations (ADTKD-UMOD) is one of the leading hereditary kidney diseases. Currently there is no targeted treatment. To illuminate human relevance of mesencephalic astrocyte-derived neurotrophic factor (MANF)-based therapy, we have established patient induced pluripotent stem cell (iPSC)-derived kidney organoid model carrying UMOD p.H177-R185del, the leading mutation causing ADTKD. We have discovered that MANF can directly bind and repress ER calcium release channel IP3R1, thus enhancing AMPK-induced autophagy in a TRIB3-dependent manner. The therapeutic implication of this finding may well be extended to other protein misfolding diseases.

genetics↗

bioRxiv2025

PEDOT:PSS Microparticles for Extrudable and Bioencapsulating Conducting Granular Hydrogel Bioelectronics

Conducting hydrogels are promising materials for forming physiomimetic bioelectronic interfaces to monitor and stimulate biological activity. However, most developed materials are non-microporous and possess fixed shapes, both of which can limit the integration of cells and tissues with devices. In non-conducting biomaterials, materials fabrication strategies imparting microporosity and dynamic mechanical properties have been shown to support cell infiltration and support biointerfaces of various geometries. Specifically, granular hydrogels have enabled encapsulating, conformal, and injectable interfaces through these features. However, granular hydrogels remain largely unexplored as conducting biomaterials. We present methods for fabricating spherical, poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) hydrogel microparticles. When densely packed, these microparticles form a conducting granular hydrogel with microporosity as well as shear-thinning and self-healing dynamic mechanical properties. The PEDOT:PSS granular hydrogel can be extruded and maintain structure post-3D printing. Modulating microparticle PSS content achieves high granular hydrogel conductivity (137 S/m), and microparticles exhibit excellent cytocompatibility (>98% viability). Finally, we demonstrate utility as bioencapsulating electrodes for electrophysiological monitoring. These results highlight the functionality of our PEDOT:PSS conducting granular hydrogel, suggesting its potential as 3D printed bioencapsulating electrodes, 3D tissue engineering scaffolds for monitoring encapsulated cells, and injectable therapies for enhanced cell recruitment and tissue regeneration combined with electronic stimulation.

bioengineering↗

bioRxiv2022

Photonic-Plasmonic Coupling Enhanced Fluorescence Enabling Digital-Resolution Ultrasensitive Protein Detection

Assays utilizing molecular fluorophores are common throughout life science research and diagnostic testing, although detection limits are generally limited by weak emission intensity, thus requiring many labeled target molecules to combine their output to achieve signal-to-noise greater than the background. Here, we describe how the synergistic coupling of plasmonic and photonic resonance modes can significantly boost the emission from fluorescent dye molecules without increasing the illumination intensity while utilizing a microscopy approach with a broad field of view. By optimally matching the resonant modes of a plasmonic fluor (PF) nanoparticle and a photonic crystal (PC) surface with the absorption and emission spectrum of the PFs fluorescent dye, we observe a 52-fold improvement in signal intensity, enabling individual PFs to be observed and digitally counted, using an approach in which one PF tag represents detection of one target molecule. The photonic amplification from the PF can be attributed to the strong near-field enhancement due to the cavity-induced activation of the PF, PC band structure-mediated improvement in collection efficiency of emitted photons, and increased rate of spontaneous emission. We demonstrate the applicability of the method by dose-response characterization of a sandwich immunoassay for human interleukin-6, a biomarker commonly used to assist diagnosis of cancer, inflammation, sepsis, and autoimmune disease. We achieve a limit of detection of 10 fg/ml, representing a capability three orders of magnitude lower than standard immunoassays.

bioengineering↗

bioRxiv2022

Neuronal Maturation-dependent Nano-Neuro Interaction and Modulation

Nanotechnology-enabled neuromodulation, a rapidly growing technique, is a promising minimally-invasive tool in neuroscience and engineering for both fundamental studies as well as clinical applications. However, the nano-neuro interactions at different stages of maturation of a neural network and its implications on the nano-neuromodulation remain unclear. Here, we report heterogeneous to homogenous transformation of neuromodulation in a progressively maturing neural network. Utilizing plasmonic fluors as ultrabright fluorescent nanolabels, we reveal that negative surface charge of the nanoparticles renders selective nano-neuro interaction with a strong correlation between the maturation stage of the individual neurons in the neural network and the density of the nanoparticles bound on the neurons. In stark contrast to homogeneous neuromodulation in a mature neural network reported so far, the maturation-dependent density of the nanoparticles bound to neurons in a developing neural network resulted in a heterogeneous optical neuromodulation (i.e., simultaneous excitation and inhibition of neural network activity). This study advances our understanding of nano-neuro interactions and nano-neuromodulation with potential applications in minimally-invasive technologies for treating neuronal disorders in parts of mammalian brain where neurogenesis persists throughout aging.

bioengineering↗

bioRxiv2022

Single cell preparations of Mycobacterium tuberculosis damage the mycobacterial envelope and disrupt macrophage interactions

For decades, investigators have studied the interaction of Mycobacterium tuberculosis (Mtb) with macrophages, which serve as a major cellular niche for the bacilli. Because Mtb are prone to aggregation, investigators rely on varied methods to disaggregate the bacteria for these studies. Here, we examined the impact of routinely used preparation methods on bacterial cell envelop integrity, macrophage inflammatory responses, and intracellular Mtb survival. We found that both gentle sonication and filtering damaged the mycobacterial cell envelope and markedly impacted the outcome of macrophage infections. Unexpectedly, sonicated bacilli were hyperinflammatory, eliciting dramatically higher TLR2-dependent gene expression and elevated secretion of IL-1{beta} and TNF-. Despite evoking enhanced inflammatory responses, sonicated bacilli replicated normally in macrophages. In contrast, Mtb that had been passed through a filter induced little inflammatory response, and they were attenuated in macrophages. Previous work suggests that the mycobacterial cell envelope lipid, phthiocerol dimycocerosate (PDIM), dampens macrophage inflammatory responses to Mtb. However, we found that the impact of PDIM depended on the method used to prepare Mtb. In conclusion, widely used methodologies to disaggregate Mtb may introduce experimental artifacts in Mtb-host interaction studies, including alteration of host inflammatory signaling, intracellular bacterial survival, and interpretation of bacterial mutants.

microbiology↗

bioRxiv2020

Explosive sensing with insect-based biorobots

Stand-off chemical sensing is an important capability with applications in several domains including homeland security. Engineered devices for this task, popularly referred to as electronic noses, have limited capacity compared to the broad-spectrum abilities of the biological olfactory system. Therefore, we propose a hybrid bio-electronic solution that directly takes advantage of the rich repertoire of olfactory sensors and sophisticated neural computational framework available in an insect olfactory system. We show that select subsets of neurons in the locust (Schistocerca americana) brain were activated upon exposure to various explosive chemical species (such as DNT and TNT). Responses from an ensemble of neurons provided a unique, multivariate fingerprint that allowed discrimination of explosive vapors from non-explosive chemical species and from each other. Notably, target chemical recognition could be achieved within a few hundred milliseconds of exposure. Finally, we developed a minimally-invasive surgical approach and mobile multi-unit electrophysiological recording system to tap into the neural signals in a locust brain and realize a biorobotic explosive sensing system. In sum, our study provides the first demonstration of how biological olfactory systems (sensors and computations) can be hijacked to develop a cyborg chemical sensing approach. SUMMARYWe demonstrate a bio-robotic chemical sensing approach where signals from an insect brain are directly utilized to detect and distinguish various explosive chemical vapors.

bioengineering↗

bioRxiv2020

Remote-controlled insect navigation using plasmonic nanotattoos

Developing insect cyborgs by integrating external components (optical, electrical or mechanical) with biological counterparts has a potential to offer elegant solutions for complex engineering problems.1 A key limiting step in the development of such biorobots arises at the nano-bio interface, i.e. between the organism and the nano implant that offers remote controllability.1,2 Often, invasive procedures are necessary that tend to severely compromise the navigation capabilities as well as the longevity of such biorobots. Therefore, we sought to develop a non-invasive solution using plasmonic nanostructures that can be photoexcited to generate heat with spatial and temporal control. We designed a nanotattoo using silk that can interface the plasmonic nanostructures with a biological tissue. Our results reveal that both structural and functional integrity of the biological tissues such as insect antenna, compound eyes and wings were preserved after the attachment of the nanotattoo. Finally, we demonstrate that insects with the plasmonic nanotattoos can be remote controlled using light and integrated with functional recognition elements to detect the chemical environment in the region of interest. In sum, we believe that the proposed technology will play a crucial role in the emerging fields of biorobotics and other nano-bio applications.

bioengineering↗