Biology subjects

Murthy, N.

Publications and source records attributed to Murthy, N..

13 recordsLinked to original sources

bioRxiv2026

Browning Lipid Nanoparticles Deliver Metabolic Benefits via Transient Conversion of White Adipose Tissue

Therapeutic strategies based on increasing uncoupled respiration (browning) in white adipose tissue (WAT) have great potential for treating obesity-related disorders such as diabetes and steatotic liver disease, but have not had a clinical impact because safe and efficient methods for browning WAT have not been developed. Lipid nanoparticles (LNPs) offer a promising platform for adipose-directed siRNA delivery; however, conventional formulations often exhibit limited activity in adipocytes and can induce inflammatory responses that may restrict repeated administration. Here we demonstrate that LNPs that contain ionizable lipids with three lipid tails and siRNAs targeting TLE3 and ZFP423 can efficiently transfect mature adipocytes and induce browning of WAT in vitro and in vivo while providing the biocompatibility needed for repeated subcutaneous injections. Repeated local administration of BLNPs in diet-induced obese mice resulted in sustained target gene silencing, increased expression of thermogenic markers, altered energy metabolism, and decreased hepatic lipid accumulation despite minimal effects on body weight relative to scramble siRNA controls. Collectively, these findings establish BLNPs as a promising platform for adipose-directed RNA delivery and targeted modulation of thermogenic pathways, providing a strategy for investigating how localized adipose tissue remodeling influences metabolic physiology.

bioengineering↗

bioRxiv2026

Chemically modified CRISPR enzymes for multi-organ genome editing in vivo

Delivery remains the main obstacle to the development of in vivo genome editing therapies. CRISPR ribonucleoproteins confer high editing activity with transient exposure but lack intrinsic cell entry and targeting. Here we introduce PERCEPT, a delivery platform featuring reversible, covalent modification of CRISPR enzymes. PERCEPT enables modular installation of shielding polymers, amphiphilic delivery peptides and targeting ligands, allowing traceless cytosolic release of the native editor. A formulation incorporating an amphiphilic delivery peptide and the neuron-targeting ligand TET1 edited approximately 56% of striatal volume and 78% of neurons within edited regions after local striatal administration. In the R6/2 Huntington's disease model, PERCEPT mediated targeted editing of the mutant human HTT transgene, reducing mutant huntingtin aggregate burden and shifting local transcriptional programs away from inflammatory and injury-associated states. Tissue-adapted formulations edited 53% of Muller glia following intravitreal delivery, increased skeletal muscle reporter fluorescence tenfold versus unconjugated control following intramuscular injection, and enabled lung airway epithelial cell that persisted for three months following intranasal delivery. Rapid screening revealed that local anatomical and cellular barriers require distinct surface display for optimal editing. These results establish reversible chemical modification as a general strategy for adapting CRISPR enzyme delivery across multiple target tissues in vivo.

bioengineering↗

bioRxiv2026

A lipid nanoparticle platform for high yield CRISPR-targeted homology directed repair enables fully non-viral CAR T cell generation

CRISPR-mediated homology directed repair (HDR) enables targeted CAR integration with improved fitness and therapeutic potential of CAR T cells. However, current methods for generating HDR-engineered CAR T cells rely on viral transduction or electroporation, approaches that limit global implementation and constrain patient access due to their cost, toxicity, and requirement for centralized manufacturing. Through a screen of ionizable lipids, we identified LNP systems that enable CRISPR-mediated gene knock-in (KI) in primary human T cells and are amenable to hand mixing by ethanol injection as a research tool or machine formulation for larger scale manufacturing. Modifying the linear dsDNA HDR template with truncated Cas9 target sequences (tCTS) enhanced HDR rates across multiple LNP systems. We optimized two LNP formulations capable of HDR-mediated KI of a large 4kB CD19 CAR-EGFR HDR template into the TRAC locus with rates of [≥]8% and >10x improved edited cell yields compared to electroporation. We demonstrate that LNP-generated CAR T cells exhibited similar growth kinetics, activation states, differentiation states, and killing capacity compared to electroporation-generated CAR T cells. Our LNP platform components are fully disclosed, commercially sourced, and enable efficient fully non-viral CRISPR-HDR cell engineering across diverse applications.

bioengineering↗

bioRxiv2026

Selective Elimination of TP53 Mutant Cells by Transcript-Activated Chromatin Shredding

Genetic mutations that drive cancer often occur in tumor suppressor proteins, including the p53 transcription factor which is altered in [~]40-50% of cases1,2. However, current therapies fail to target most such mutations because the mutant proteins typically lack defined drug-binding pockets, and restoring the endogenous function has proven challenging. Here, we programmed CRISPR-Cas12a2, an RNA-guided nuclease with trans-nucleolytic cleavage activities3,4, to selectively kill cancer cells by targeting cancer-specific transcripts. This approach eliminates cells by inducing trans chromatin cleavage, triggering DNA damage and cell death. Unlike existing methods, RNA-guided Cas12a2 senses cellular RNA signatures to shred chromatin, enabling precise targeting of undruggable mutations. Transcript-activated chromatin shredding provides an innovative paradigm to develop precision disease treatments for undruggable targets.

cell biology↗

bioRxiv2025

Efficient in vivo mammalian neuron editing using peptide-mediated CRISPR enzyme delivery

CRISPR-mediated genome editing of the central nervous system (CNS) has the potential to revolutionize the treatment of neurological disorders, including neurodegenerative disorders such as Huntingtons disease (HD). However, the development of CRISPR therapeutics for the CNS has been hindered by challenges associated with delivery, specifically the lack of a clinically compatible, non-viral delivery technology facilitating genome editing of neurons in vivo. For most indications, two key obstacles must be overcome before therapeutic genome editing of the brain is feasible: non-toxic intracellular delivery of CRISPR cargo into neurons and establishment of strategies enabling targeted brain regions to be edited efficiently. While viral vectors have shown promise in pre-clinical models, non-viral approaches present distinct advantages: ease of manufacture as well as the transient presence of CRISPR machinery, which tempers risks of genotoxicity and immunogenicity. Peptide-enabled ribonucleoprotein (RNP) delivery of CRISPR (PERC) has emerged as a promising non-viral delivery strategy for CRISPR enzymes with initial use in primary human immune cells. In this study, we report the development of Neuro-PERC, a streamlined and optimized approach for in vivo editing of mammalian neurons. Administration of Neuro-PERC reagents via convection-enhanced delivery (CED) mediated efficient and well-tolerated neuronal genome editing. Neuro-PERC enabled robust neuronal editing in the brain of both small and large animal reporter models, and increased survival in a severe murine model of Huntingtons disease. These results establish CED-administered Neuro-PERC as a candidate delivery technology to hasten clinical translation of CRISPR-based therapies for diseases of the CNS. SummaryNeuro-PERC, a peptide-mediated CRISPR enzyme delivery technology, enables efficient in vivo mammalian neuronal editing in the brain of mice and pigs, extending survival in a murine model of Huntingtons disease when administered via convection-enhanced delivery (CED).

neuroscience↗

bioRxiv2025

CRISPR-Cas13d-mediated targeting of a context-specific essential gene enables selective elimination of uveal melanoma

Uveal melanoma, the most common eye cancer in adults, remains limited to surgical intervention and chemotherapy, with a dismal survival rate that has not improved in over 50 years. To address this therapeutic impasse, we systematically analyzed public gene expression, RNAi, and CRISPR knockout datasets and identified RASGRP3 as an essential gene specifically for uveal melanoma. RasGRP3 is uniquely overexpressed and essential for survival in uveal melanoma cells, but dispensable in healthy cells. RasGRP3 remains "undruggable" due to its intracellular localization and lack of targetable binding pockets. To overcome this, we developed a CRISPR-Cas13d RNA-targeting therapeutic that specifically knocks down RasGRP3 mRNA. This Cas13d-based therapeutic mediates selective uveal melanoma killing through two synergistic mechanisms: (i) direct silencing of the essential RasGRP3 transcript, and (ii) collateral RNA degradation triggered by the cleavage of overexpressed RasGRP3. When delivered via optimized lipid nanoparticles encoding Cas13d mRNA and guide RNA, this strategy eliminated >97% of uveal melanoma cells while sparing healthy cells, including retinal pigment epithelial cells. This approach outperformed conventional Cas9 and siRNA methods in potency without inducing permanent genomic alterations. Our findings establish a RNA-targeting therapeutic for uveal melanoma and a framework for Cas13d-based interventions against broad "undruggable" cancers.

synthetic biology↗

bioRxiv2025

Swine reporter model for preclinical evaluation and characterization of gene delivery vectors

Delivery of gene therapy vectors targeted to any somatic cell remains a key barrier for the development of genetic medicines. While rodent models provide insights into vector biodistribution and cellular tropism, their anatomical and physiological differences from humans limit their translational potential and studies in large animal models are often required. In this study, we developed a swine reporter model (SRM-1) to evaluate both viral and nonviral vector delivery in a large animal system. The SRM-1 model harbors a Cre- and CRISPR-activated tdTomato reporter at the Rosa26 locus that allows for tracing of cell-specific delivery and expression of gene therapy vectors in vivo. To evaluate this model, we administered adeno-associated virus serotype 9 (AAV9) and lipid nanoparticles (LNPs) carrying mRNA systemically and found successful in vivo reporter activation across a variety of tissues. Intracerebroventricular (ICV) administration of LNP-Cre mRNA was also performed and demonstrated localized activation in cortical brain cells. In addition to biodistribution studies, this model has utility for testing safety and clinically relevant administration methods, surgical and non-surgical, of delivery vectors. Our findings support the SRM-1 model as a valuable tool for advancing gene therapies from preclinical testing to clinical application.

genetics↗

bioRxiv2025

A cardiac microphysiological system for screening lipid nanoparticle/mRNA complexes predicts in vivo efficacy for heart transfection

Lipid nanoparticle (LNP)/mRNA complexes have tremendous potential for treating cardiac diseases but lack the transfection efficiency required for successful heart therapeutics. A challenge preventing the development of cardiac LNPs is the lack of in vitro screening platforms that maximize transfection and predict efficacy. Here, we demonstrate that a phenotypic cardiac microphysiological system (MPS), constructed from a human induced pluripotent stem cell cardiomyocytes (hiPSC-CM) Cre-reporter line, can identify LNP/mRNA complexes that diffuse efficiently within 3D cardiac micromuscles and transfect cardiomyocytes with high efficiency. Successful LNP formulations contained an acid-degradable PEG (ADP)-lipid, where ADP-LNPs containing 10% PEG had enhanced diffusion and gene editing efficiency in the cardiac MPS. The in vivo delivery of LNP/mRNA complexes, including luciferase and CRE mRNA, into Ai6 mice confirmed the cardiac MPS screening outcomes. It revealed that ADP-LNPs achieved notably superior transfection in the heart with reduced off-target liver uptake compared to a standard LNP formulation. The cardiac MPS showed strong LNP transfection in vitro and pinpointed a promising formulation for in vivo mRNA delivery to the heart.

bioengineering↗

bioRxiv2024

Neuronal DNA repair reveals strategies to influence CRISPR editing outcomes

Genome editing is poised to revolutionize treatment of genetic diseases, but poor understanding and control of DNA repair outcomes hinders its therapeutic potential. DNA repair is especially understudied in nondividing cells like neurons, which must withstand decades of DNA damage without replicating. This lack of knowledge limits the efficiency and precision of genome editing in clinically relevant cells. To address this, we used induced pluripotent stem cells (iPSCs) and iPSC-derived neurons to examine how postmitotic human neurons repair Cas9-induced DNA damage. We discovered that neurons can take weeks to fully resolve this damage, compared to just days in isogenic iPSCs. Furthermore, Cas9-treated neurons upregulated unexpected DNA repair genes, including factors canonically associated with replication. Manipulating this response with chemical or genetic perturbations allowed us to direct neuronal repair toward desired editing outcomes. By studying DNA repair in postmitotic human cells, we uncovered unforeseen challenges and opportunities for precise therapeutic editing.

molecular biology↗

bioRxiv2024

Synthesis of ionizable lipopolymers using split-Ugi reaction for pulmonary delivery of various size RNAs and gene editing

We present an efficient approach for synthesizing cationic poly(ethylene imine) derivatives using the multicomponent split-Ugi reaction to rapidly create a library of complex functional ionizable lipopolymers. We synthesized a diverse library of 155 polymers, formulated them into polyplexes to establish structure-activity relationships crucial for endosomal escape and efficient transfection. After discovering a lead structure, lipopolymer-lipid hybrid nanoparticles are introduced to preferentially deliver to and elicit effective mRNA transfection in lung endothelium and immune cells, including T cells with low in vivo toxicity. The lipopolymer-lipid hybrid nanoparticles showed 300-fold improvement in systemic mRNA delivery to the lung compared to in vivo-JetPEI(R). Lipopolymer-lipid hybrid nanoparticles demonstrated efficient delivery of mRNA-based therapeutics for treatment of two different disease models. Lewis Lung cancer progression was significantly delayed after treatment with loaded IL-12 mRNA in U155@lipids after repeated i.v. administration. Systemic delivery of human CFTR (hCFTR) mRNA resulted in production of functional form of CFTR protein in the lungs. The functionality of hCFTR protein was confirmed by restoration of CFTR- mediated chloride secretion in conductive airway epithelia in CFTR knockout mice after nasal instillation of hCFTR mRNA loaded U155@lipids. We further showed that, U155@lipids nanoparticles can deliver complex CRISPR-Cas9 based RNA cargo to the lung, achieving 5.6 {+/-} 2.4 % gene editing in lung tissue. Moreover, we demonstrated successful PD-1 gene knockout of T cells in vivo. Our results highlight a versatile delivery platform for systemic delivering of mRNA of various sizes for gene therapy for a variety of therapeutics.

bioengineering↗

bioRxiv2023

Lung and liver editing by lipid nanoparticle delivery of a stable CRISPR-Cas9 RNP

Lipid nanoparticle (LNP) delivery of CRISPR ribonucleoproteins (RNPs) has the potential to enable high-efficiency in vivo genome editing with low toxicity and an easily manufactured technology, if RNP efficacy can be maintained during LNP production. In this study, we engineered a thermostable Cas9 from Geobacillus stearothermophilus (GeoCas9) using directed evolution to generate iGeoCas9 evolved variants capable of robust genome editing of cells and organs. iGeoCas9s were significantly better at editing cells than wild-type GeoCas9, with genome editing levels >100X greater than those induced by the native GeoCas9 enzyme. Furthermore, iGeoCas9 RNP:LNP complexes edited a variety of cell lines and induced homology-directed repair (HDR) in cells receiving co-delivered single-stranded DNA (ssDNA) templates. Using tissue-selective LNP formulations, we observed genome editing of 35-56% efficiency in the liver or lungs of mice that received intravenous injections of iGeoCas9 RNP:LNPs. In particular, iGeoCas9 complexed to acid-degradable LNPs edited lung tissue in vivo with an average of 35% efficiency, a significant improvement over editing efficiencies observed previously using viral or non-viral delivery strategies. These results show that thermostable Cas9 RNP:LNP complexes are a powerful alternative to mRNA:LNP delivery vehicles, expanding the therapeutic potential of genome editing.

bioengineering↗

bioRxiv2022

Non-viral gene editing in utero with lipid nanoparticles complexed to mRNA

Nanoparticle-based drug delivery systems have the potential to revolutionize medicine but their low vascular permeability and rapid clearance by phagocytic cells have limited their medical impact. Nanoparticles delivered at the in utero stage have the potential to overcome these key limitations, due to the high rate of angiogenesis and cell division in fetal tissue, and the under-developed immune system. However, very little is known about nanoparticle drug delivery at the fetal stage of development. In this report, using Ai9 CRE reporter mice, we demonstrate that lipid nanoparticle (LNP) mRNA complexes can deliver mRNA for gene editing enzymes in utero after an intrahepatic injection, and can access and edit major organs, such as the heart, the liver, kidneys, lungs and the gastrointestinal tract with remarkable efficiency and low toxicity. In addition, we show here that Cas9 mRNA and sgRNA complexed to LNPs were able to edit the fetal organs in utero after an intrahepatic injection. These experiments demonstrate the possibility of non-viral delivery of gene editing enzymes in utero and nanoparticle drug delivery has great potential for delivering macromolecules to organs outside of the liver in utero, which provides a promising strategy for treating a wide variety of devastating genetic diseases before birth.

genetics↗

bioRxiv2020

Screening a library of FDA-approved and bioactive compounds for antiviral activity against SARS-CoV-2

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of coronavirus disease 2019 (COVID-19), has emerged as a major global health threat. The COVID-19 pandemic has resulted in over 80 million cases and 1.7 million deaths to date while the number of cases continues to rise. With limited therapeutic options, the identification of safe and effective therapeutics is urgently needed. The repurposing of known clinical compounds holds the potential for rapid identification of drugs effective against SARS-CoV-2. Here we utilized a library of FDA-approved and well-studied preclinical and clinical compounds to screen for antivirals against SARS-CoV-2 in human pulmonary epithelial cells. We identified 13 compounds that exhibit potent antiviral activity across multiple orthogonal assays. Hits include known antivirals, compounds with anti-inflammatory activity, and compounds targeting host pathways such as kinases and proteases critical for SARS-CoV-2 replication. We identified seven compounds not previously reported to have activity against SARS-CoV-2, including B02, a human RAD51 inhibitor. We further demonstrated that B02 exhibits synergy with remdesivir, the only antiviral approved by the FDA to treat COVID-19, highlighting the potential for combination therapy. Taken together, our comparative compound screening strategy highlights the potential of drug repurposing screens to identify novel starting points for development of effective antiviral mono- or combination therapies to treat COVID-19.

microbiology↗