Biology subjects

Nagapudi, K.

Publications and source records attributed to Nagapudi, K..

5 recordsLinked to original sources

bioRxiv2026

DSPE-PEG does not retain targeting antibodies on LNP surfaces in vivo; a higher molecular weight anchor is required

Extrahepatic delivery of lipid nanoparticles (LNPs) to non-phagocytic cells is a major challenge, with the leading strategy involving surface functionalization with target-specific monoclonal antibody (mAb) ligands. We investigate the stability of mAb-conjugated LNPs using two anchoring systems: the commonly used DSPE-PEG2kDa-maleimide and a block copolymer, PCL5kDa-b-PEG2kDa -maleimide, with the hypothesis that conjugation to a 150,000 Da antibody could overwhelm the relatively small [~]600 Da aliphatic anchor on the PEG-lipid in vivo. Shedding of the mAB would compromise targeting. Conjugation integrity following IV injection was assessed by tagging LNPs and mAbs with metal ion tracers that could be quantified by ICP-MS. Results show that DSPE-PEG-mAb rapidly (within 1h) dissociates from LNPs in blood, leading to accelerated LNP clearance. In contrast, mAbs conjugated using PCL-b-PEG remained stably associated with the LNP over the 24h circulation and clearance of the construct. Results are connected to a thermodynamic model that reproduces experimental findings for PEG-anchor(-mAb) shedding in vitro and in vivo. This study identifies anchoring strength as a critical, unconsidered parameter for in vivo performance when conjugating mAbs to LNPs for extrahepatic delivery. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=123 SRC="FIGDIR/small/736109v1_ufig1.gif" ALT="Figure 1"> View larger version (44K): org.highwire.dtl.DTLVardef@fd783eorg.highwire.dtl.DTLVardef@e1351borg.highwire.dtl.DTLVardef@165ab26org.highwire.dtl.DTLVardef@1c752a9_HPS_FORMAT_FIGEXP M_FIG C_FIG

pharmacology and toxicology↗

bioRxiv2024

Opto-Myomatrix: μLED integrated microelectrode arrays for optogenetic activation and electrical recording in muscle tissue

ObjectiveOptogenetics is a valuable and widely-used technique that allows precise perturbations of selected groups of cells with high temporal and spatial resolution by using optical systems and genetic engineering technologies. This study aims to develop Opto-Myomatrix, a novel optogenetic tool for precise muscle fiber control and high-resolution electrophysiological recording. MethodBased on a flexible and biocompatible polymer substrate, the device incorporates an integrated {micro}LED that delivers light at 465 nm for optogenetic stimulation and 32 PEDOT:PSS-coated electrodes for electromyography (EMG) recording. We also added a reflector to improve optical power output. ResultsThe fabricated Opto-Myomatrix device achieves an optical output intensity as high as 129.46 mW/mm2 in the direction of interest, which is enhanced by nearly 100%. The PEDOT:PSS-coated electrodes exhibit 85% lower impedance than uncoated contacts, enabling high signal-to-noise EMG acquisition. We investigated heat dissipation characteristics of the {micro}LED through measurements and finite element simulations, confirming that temperature changes remain within safe limits. The Opto-Myomatrix device was implanted in transgenetic mice and successfully stimulated targeted jaw muscles, inducing movement while simultaneously capturing EMG signals. ConclusionThe Opto-Myomatrix effectively combines precise optical stimulation and high-quality EMG recording in a flexible and biocompatible device, focusing on optogenetic applications in muscle. SignificanceWhile optogenetic tools are well-established for brain and central nervous system (CNS) research, the development of Opto-Myomatrix addresses a critical gap by enabling precise muscle fiber control and high-resolution recording for advancing neuromuscular studies.

bioengineering↗

bioRxiv2024

Engineering ERα degraders with pleiotropic ubiquitin ligase ligands maximizes therapeutic efficacy by co-opting distinct effector ligases

Proximity-inducing compounds that modulate target protein homeostasis are an emerging therapeutic strategy [1]. While the inherent complexity of these bifunctional compounds poses challenges for rational design and bioavailability, their composition also provides opportunities to co-opt specific cellular proteins to maximize therapeutic impact. Here, we systematically evaluate the cellular efficacy, biophysical mechanisms, and therapeutic benefits of a series of bifunctional degrader compounds, that are all engineered with the Estrogen Receptor-alpha (ER)-inhibitor endoxifen linked to different bioactive ubiquitin ligase ligands. Bifunctional ER degraders that incorporate CRL4-CRBN-binding ligands promoted the most potent ER degradation, whereas those incorporating either CRL2-VHL- or IAP-binding ligands maximized the depth of ER degradation. Notably, ER degraders containing pan-IAP antagonist ligands significantly decreased the proliferation of ER-dependent cells relative to clinical-stage ER-degraders, including the SERDs fulvestrant and GDC-9545 and the bifunctional degrader ARV-471. Mechanistic studies revealed that pan-IAP antagonist-based ER degraders uniquely promote TNF-dependent cell death, unlike the clinical-stage comparators. Remarkably, the pan-IAP antagonist-ER-degraders co-opt distinct effector ligases to achieve dual therapeutic effects: they harness XIAP within tumor cells to promote ER degradation, and activate cIAP1/2 within tumor and immune cells to induce TNF that drives tumor cell death. Our studies demonstrate a broader concept that co-opting the discrete functions of a selected set of cellular effectors, while simultaneously modulating therapeutic target protein homeostasis, are dual strategies that can be leveraged to maximize the efficacy of induced proximity therapeutics.

cancer biology↗

bioRxiv2023

Myomatrix arrays for high-definition muscle recording

Neurons coordinate their activity to produce an astonishing variety of motor behaviors. Our present understanding of motor control has grown rapidly thanks to new methods for recording and analyzing populations of many individual neurons over time. In contrast, current methods for recording the nervous systems actual motor output - the activation of muscle fibers by motor neurons - typically cannot detect the individual electrical events produced by muscle fibers during natural behaviors and scale poorly across species and muscle groups. Here we present a novel class of electrode devices ("Myomatrix arrays") that record muscle activity at unprecedented resolution across muscles and behaviors. High-density, flexible electrode arrays allow for stable recordings from the muscle fibers activated by a single motor neuron, called a "motor unit", during natural behaviors in many species, including mice, rats, primates, songbirds, frogs, and insects. This technology therefore allows the nervous systems motor output to be monitored in unprecedented detail during complex behaviors across species and muscle morphologies. We anticipate that this technology will allow rapid advances in understanding the neural control of behavior and in identifying pathologies of the motor system.

neuroscience↗

bioRxiv2022

Injectable polymer-nanoparticle hydrogel for the sustained intravitreal delivery of bimatoprost

Vision impairment resulting from chronic eye diseases, such as macular degeneration and glaucoma, severely impacts patients quality of life and poses an immense global financial burden. Current standard of care for such diseases includes daily eye drops or frequent intravitreal (ITV) injections, which are burdensome treatment modalities resulting in low patient compliance. There remains a growing need for easily administered long-acting delivery technologies for prolonging exposure of ocular therapeutics with each administration. Here, we deploy a supramolecular polymer-nanoparticle (PNP) hydrogel for ITV delivery of the glaucoma drug bimatoprost. PNP hydrogels are shear-thinning and self-healing, key properties for injectability, and enable slow release of molecular cargo in vitreous humor (VH) mimics. An in vivo study in New Zealand white rabbits demonstrated intravitreally injected PNP hydrogels form depots that degrade slowly over time, maintaining detectable levels of bimatoprost in the VH up to eight weeks following injection. Ophthalmic examinations and histopathology identified a mild foreign body response (FBR) to the hydrogel, characterized by rare clusters of foamy macrophages and giant cells associated with minimal, patchy fibroplasia. This work shows that PNP hydrogels exhibit numerous desirable traits for sustained drug delivery and further work will be necessary to optimize tolerability in the eye.

bioengineering↗