Biology subjects

Omri, S.

Publications and source records attributed to Omri, S..

3 recordsLinked to original sources

bioRxiv2026

Fucoidan-Coated Layer-by-layer Lipid Nanoparticles for the Generation of CAR-Macrophages

Modulation of immune cells as therapeutic tools has gained significant clinical relevance in the treatment of cancer. Among them, macrophages represent a promising immunotherapeutic platform not only because they can internalize tumor material, but also because they profoundly shape the tumor microenvironment through cytokine production, antigen presentation, metabolic regulation, and modulation of other immune and stromal populations. Lipid Nanoparticles (LNPs) have enabled RNA therapies to the bedside and are thus considered the gold standard for gene delivery. However, optimizing LNPs for RNA delivery to macrophages remains an active area of investigation. Here, we propose the surface modification of unPEGylated LNPs using the Layer-by-Layer (LbL) approach for enhanced RNA delivery to macrophages. Specifically, we show that fucoidan, a sulfated polysaccharide, when at the outermost layer in the LbL process provides two physicochemical advantages to unPEGylated LNPs: (1) stability in PBS and (2) resistance to lyophilization in the presence of cryoprotectant. Additionally, fucoidan improves macrophage targeting and RNA transfection efficiency compared to previously synthesized hyaluronan-decorated LbL LNPs. Fucoidan LbL LNPs (Fuc-LNPs) preferentially accumulated in CD11b+ macrophages when co-cultured with U87 glioblastoma cells, which was not observed for control PEGylated LNPs. Furthermore, Fuc-LNPs induced a higher transfection of mRNA in primary human macrophages when compared to PEGylated control LNPs. Using the model mRNA encoding CAR@CD19, Fuc-LNPs generated CAR macrophages which mediated CD19 cell ablation in vitro. Altogether, these findings highlight the potential of the LbL strategy to modulate the targeting properties of LNPs, improving RNA delivery to human macrophages and encouraging further studies using LbL LNPs for the generation of CAR-Macrophages in the context of solid tumors.

bioengineering↗

bioRxiv2026

Clinically relevant AAV8-PEX1 gene therapy preserves retinal integrity and function long-term in a murine model of Zellweger spectrum disorder

Inherited retinal diseases (IRDs) are a heterogeneous group of genetic disorders that cause progressive vision loss. A subset of IRDs is associated with ubiquitously expressed genes involved in fundamental cellular processes, often resulting in multisystem disease. Among these is Zellweger spectrum disorder (ZSD), caused by pathogenic variants in PEX genes required for peroxisome biogenesis and function. There are no proven targeted disease-modifying treatments for ZSD, and it is unclear whether localized restoration of peroxisome function is sufficient to mitigate retinal degeneration. We previously demonstrated that HsPEX1 retinal gene augmentation therapy in a mouse model of mild ZSD homozygous for the murine equivalent (PEX1-p.[Gly844Asp]) of the most common deleterious allele in patients (PEX1-c.[2528G>A], PEX1-p.[Gly843Asp]), improved retinal electrophysiological response. Here, we present a comprehensive, dose-range evaluation of a re-designed, clinically relevant AAV8-delivered HsPEX1 subretinal gene therapy, employing expanded outcome measures. We observed a marked improvement in functional vision, retinal response, photoreceptor structure, retinal pigment epithelium integrity, subretinal inflammation, and peroxisomal metabolites, durable to the endpoint of 6 months post single subretinal injection. These studies provide preclinical proof-of-concept that localized retinal gene replacement can mitigate vision loss in peroxisome-mediated IRD.

genetics↗

bioRxiv2024

Geographic characterization of RPE structure and lipid changes in the PEX1-p.Gly844Asp mouse model for Zellweger spectrum disorder.

Peroxisome Biogenesis Disorders-Zellweger Spectrum (PBD-ZSD) are a heterogenous group of autosomal recessive disorders caused by defects in PEX genes whose proteins are required for peroxisome assembly and function. Peroxisomes are ubiquitous organelles that play a critical role in complex lipid metabolism. Dysfunctional peroxisomes in ZSD cause multisystem effects, with progressive retinal degeneration (RD) leading to childhood blindness being one of the most frequent clinical findings. Despite progress in understanding the role of peroxisomes in normal cellular functions, much remains unknown about how their deficiency causes RD, and there is no treatment. To study RD pathophysiology in this disease, we used the knock-in PEX1-p.GlyG844Asp (G844D) mouse model of milder ZSD, which represents the common human PEX1-p.Gly843Asp allele. We previously reported diminished retinal function, functional vision, and neural retina structural defects in this model. Beyond the neural retina, structural defects in retinal pigment epithelium (RPE) have been reported in ZSD patients and murine models with single peroxisome enzyme deficiency, suggesting that RPE degeneration may contribute to overall RD progression in this disease. Here, we investigate the RPE phenotype in our PEX1-G844D mouse model, observing morphological, inflammatory, and lipid changes at 1, 3, and 6 months of age. We report that RPE cell degeneration appears at 3 months of age and worsens with time, starts in the dorsal pole, and is accompanied by subretinal inflammatory cell infiltration. We match these events with lipid remodelling using imaging mass spectrometry which allowed regional analysis specific to the RPE cell layer. We identified 47 lipid alterations that precede structural changes, 10 of which are localized to the dorsal pole. 32 of these lipid alterations persist to 3 months, with remodelling of the lipid signature at the dorsal pole. 14 new alterations occur concurrent with histological changes. Changes in peroxisome-dependent lipids detected by liquid chromatography tandem mass spectrometry (reduced docosahexanoic acid and increased very long chain lysophosphatidylcholines) are exacerbated over time. This study represents the first characterization of RPE in any animal model of ZSD, and the first in situ lipid analysis in any peroxisome-deficient tissue. Our findings reveal candidate lipid drivers that could be targeted to alleviate RD progression in ZSD, as well as candidate biomarkers that could be used to evaluate retinopathy progression and response to therapy.

pathology↗