Wendler, A. | Search bioRxiv

bioRxiv2021

Phagocytosed polyhedrin-cytokine co-crystal nanoparticles provide sustained secretion of bioactive cytokines from macrophages

Many cells possess the ability to engulf and incorporate particles by phagocytosis. This active process is characteristic of microorganisms as well as higher order species. In mammals, monocytes, macrophages and microglia are among so-called professional phagocytes. In addition, cells such as fibroblast and chondrocytes are classified as non-professional phagocytes. Professional phagocytes play important roles in both the innate and adaptive immune response, wound healing and tissue homeostasis. Consequently, these cells are increasingly studied as targets and vectors of therapeutic intervention to treat a range of diseases. Professional phagocytes are notoriously difficult to transfect limiting their study and manipulation. Consequently, efforts have shifted towards the development of nanoparticles to deliver a cargo to phagocytic cells via phagocytosis. However, this approach carries significant technical challenges, particularly for protein cargos. We have focused on the development of nanoscale co-crystalline protein depots, known as PODS(R), that contain protein cargos, including cytokines. Here, we show that PODS are readily phagocytosed by non-professional as well as professional phagocytic cells and have attributes, such as highly sustained release of cargo, that suggest potential utility for the study and exploitation of phagocytic cells for drug delivery. Monocytes and macrophages that ingest PODS retain normal characteristics including a robust chemotactic response. Moreover, the PODS-cytokine cargo is secreted by the loaded cell at a level sufficient to modulate the behavior of surrounding non-phagocytic cells. The results presented here demonstrate the potential of PODS nanoparticles as a novel molecular tool for the study and manipulation of phagocytic cells and for the development of Trojan horse immunotherapy strategies to treat cancer and other diseases.

bioengineering↗

bioRxiv2020

Spatial heterogeneity of cell-matrix adhesive forces predicts human glioblastoma migration

BackgroundGlioblastoma (GBM) is a highly aggressive incurable brain tumor. The main cause of mortality in GBM patients is the invasive rim of cells migrating away from the main tumor mass and invading healthy parts of the brain. Although motion is driven by forces, our current understanding of the physical factors involved in glioma infiltration remains limited. This study aims to investigate the adhesion properties within and between patients tumors on a cellular level and test whether these properties correlate with cell migration. MethodsNine tissue samples were taken from spatially separated sections during 5-aminolevulinic acid (5-ALA) fluorescence guided surgery. Navigated biopsy samples were collected from strongly fluorescent tumor cores, a weak fluorescent tumor rim, and non-fluorescent tumor margins. A microfluidics device was built to induce controlled shear forces to detach cells from monolayer cultures. Cells were cultured on low modulus polydimethylsiloxane representative of the stiffness of brain tissue. Cell migration and morphology were then obtained using time lapse microscopy. ResultsGBM cell populations from different tumor fractions of the same patient exhibited different migratory and adhesive behaviors. These differences were associated with sampling location and amount of 5-ALA fluorescence. Cells derived from weak- and non-fluorescent tumor tissue were smaller, adhered less well, and migrated quicker than cells derived from strongly fluorescent tumor mass. ConclusionGBM tumors are biomechanically heterogeneous. Selecting multiple populations and broad location sampling are therefore important to consider for drug testing. Key pointsGBM tumors are biomechanically heterogeneous GBM cell migration is inversely correlated with cell-matrix adhesion strength 5-ALA fluorescence intensity during surgery correlates with the motility properties of GBM cells Importance of the studyThis is the first study to compare single cell migration and cell-matrix adhesion strength of GBM, using cell lines derived from different tumors and from different regions within the same tumor. Not accounting for internal sampling location within each tumor obscures differences in cell morphology, motility and adhesion properties between patients. Peripherical and marginal tumor cells have different adhesion profiles and are highly migratory compared to those found in the core of the tumor. Aggressive regions of the tumor (highly motile) are linked to the spatial distribution of adhesion strength and are strongly associated with 5-ALA fluorescence intensity. Preclinical tests aimed at developing a treatment for GBM using anti-invasive drugs or adhesion inhibitors, would benefit from using cell lines derived from the tumor periphery (with low 5-ALA intensity) rather than cell lines derived from the tumor core.

biophysics↗