Biology subjects

Cahn, D.

Publications and source records attributed to Cahn, D..

3 recordsLinked to original sources

bioRxiv2025

Barrier Function of the Extracellular Matrix in AAV Gene Therapy

PurposeThe extracellular matrix (ECM) is a major component of the tissue microenvironment which may pose a barrier to the distribution of AAV in target organs, preventing delivery of therapeutic cargo. We sought to address this potential barrier to AAV gene therapy by furthering our understanding of AAV-ECM interactions. We hypothesized that both the AAV serotype and ECM composition will impact AAV transport and gene delivery. MethodsAAV2, AAV6, and AAV8 viral vectors were fluorescently labeled to allow for visualization of their diffusion through the ECM. Lung, liver, and small intestinal submucosal dECM hydrogels were formulated as models of the ECM with tissue-specific biomolecular content. We then characterized AAV and nanoparticle diffusion within decellularized ECM using fluorescent video microscopy and multiple particle tracking. Additionally, we evaluated AAV transduction in dECM-incorporated 2D and 3D spheroid tissue culture models. ResultsAll AAV displayed reduced diffusivity through ECM as compared to similarly sized nanoparticles. AAV2 diffusion was least affected by the presence of ECM across tissue types as compared to AAV6 and AAV8. AAV transduction in dECM incorporated in vitro models was significantly reduced in both a 2D and 3D setting. ConclusionsThese results suggest binding of AAV to the ECM may decrease their therapeutic effect in target tissues throughout the body. The barrier function of the ECM should be considered in development of AAV for gene therapy applications.

bioengineering↗

bioRxiv2025

PEGylation strategies for enhanced nanoparticle delivery to tumor associated immune cells

Barriers to nanoparticle drug delivery to the tumor microenvironment such as ECM deposition and clearance by the mononuclear phagocyte system have necessitated strategies for more effective tumor penetration. Adding polyethylene glycol (PEG) chains to the surface of nanoparticles (PEGylation) has been widely used to both enhance accumulation at the tumor site and increase blood circulation time. Recent work has also shown that immune cells (e.g. macrophages, dendritic cells, neutrophils) play an important role in the ability of NPs to effectively target and spread within a tumor. PEG chain characteristics such as size and branching affects how nanoparticles interact with tissues; however, it is unclear how PEGylation type affects NP uptake and cellular distribution in the tumor microenvironment. In this study, we evaluated the influence of both linear and branched PEGylation on nanoparticle biodistribution and uptake in tumor cells as well as tumor-infiltrating immune cells. As compared to conventional surface coatings with linear PEG, we show that modifying PEG structure to a branched conformation increases nanoparticle accumulation in the spleen of tumor-bearing mice, primarily due to significantly enhanced uptake by leukocytes. As compared to uncoated particles, we also found that nanoparticles densely coated with linear or branched PEG accumulated to a greater extent in tumors showing [≥]8-fold increases in uptake by tumor-associated macrophages and dendritic cells. These studies provide insight into PEG architecture as a design parameter in nanomedicine that can facilitate the design of more effective cancer therapies. Translational ImpactThis work uncovers immune-mediated mechanisms and design strategies to enhance NP delivery to tumors via PEGylation which provide a foundation for clinical development of cancer therapeutics. The PEGylation strategies described could be readily integrated into clinically relevant nanoparticle delivery systems (e.g. lipid nanoparticles) with minimal effort making this a highly appealing approach to address the current limitations of cancer nanomedicine.

bioengineering↗

bioRxiv2024

The Extracellular Matrix Limits Nanoparticle Diffusion and Cellular Uptake in a Tissue-Specific Manner

Overexpression and remodeling of the extracellular matrix (ECM) in cancer and other diseases may significantly reduce the ability of nanoparticles to reach target sites, preventing effective delivery of therapeutic cargo. Here, we evaluate how tissue-specific properties of the ECM affect nanoparticle diffusion using fluorescence video microscopy and cellular uptake via flow cytometry. In addition, we determined how PEGylation chain size and branching influence the ability of nanoparticles to overcome the ECM barrier from different tissues. We found that purified collagen, in the absence of other ECM proteins and polysaccharides, presented a greater barrier to nanoparticle diffusion as compared to decellularized ECM from the liver, lung, and small intestine submucosa. Nanoparticles with dense PEG coatings achieved up to [~]2000-fold enhancements in diffusion rate and cellular uptake up to [~]5-fold greater than non-PEGylated nanoparticles in the presence of ECM. We also found nanoparticle mobility in the ECM varied significantly between tissue types and the optimal nanoparticle PEGylation strategy to enhance ECM penetration was strongly dependent on ECM concentration. Overall, our data supports the use of low molecular weight PEG coatings which provides an optimal balance of nanoparticle penetration through ECM and uptake in target cells. However, tissue-specific enhancements in ECM penetration and cellular uptake were observed for nanoparticles bearing a branched PEG coating. These studies provide new insight into tissue specific ECM barrier functions which can facilitate the design of nanoparticles that effectively transport through target tissues, improving their therapeutic efficacy.

bioengineering↗