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Biology subjects

Högberg, B.

Publications and source records attributed to Högberg, B..

4 recordsLinked to original sources

A combinatorial DNA origami platform for biologically replicable, thermostable data storage and molecular authentication

DNA origami is becoming an attractive platform for data storage, yet current approaches rely on the limited stability of DNA hybridization, preventing them from fully utilizing the stability and cost-effective copying inherent to classical sequence-based storage. Here we introduce DNA Origami for Combinatorial data Storage (DOCS), where we encode information into the scaffold molecule using a combinatorial enzymatic approach. This enables text encoding that is biologically cloneable, stable at high temperatures, and randomly accessible. We further demonstrate the DOCS platforms combinatorial power by creating a stochastic molecular authentication system. Finally, we show using simulations that expanding the information capacity of data carriers allows for the storage and recovery of large files up to several hundred kilobytes in size. DOCS provides a robust, scalable strategy for molecular data storage and security that bridges the gap between classical DNA data storage strategies and DNA nanostructure-based methods.

bioengineering↗

Notch engagement by Jag1 nanoscale clusters indicates a force-independent mode of activation

The Notch signaling pathway is a cell-cell communication system with fundamental roles in embryonic development and the nervous system. The model of Notch receptor activation that is currently most accepted, involves a force-induced conformation change at the negative regulatory region of the receptor, the subsequent recruitment of ADAM metalloproteases and a cleavage cascade that releases the Notch intracellular domain. Here, we define conditions that enable force-independent Notch activation through the formation of soluble, long-lived, multivalent ligand-receptor complexes. To investigate how ligand valency affects activation of Notch receptors, we treated iPSc-derived neuroepithelial stem-like (lt-NES) cells with different spatially defined, molecularly precise ligand nanopatterns on DNA origami nanostructures. Our data indicate that Notch signaling is activated via stimulation with multivalent clusters of the ligand Jag1, and even multivalent chimeric structures where some Jag1 proteins are replaced by other binders that do not target Notch. The findings are corroborated by systematic elimination, through experimental control, of several confounding factors that potentially could generate forces, including electrostatic interactions, endocytosis and non-specific binding. Taken together, our data suggest a model where Jag1 ligands are able to activate Notch receptors upon prolonged binding, which subsequently triggers downstream signaling in a force independent manner. These findings reveal a distinct mode of activation of Notch and could lay the foundation for the development of soluble Notch agonists that currently remain elusive.

cell biology↗

Clustering of death receptor for apoptosis using nanoscale patterns of peptides

The nanoscale spatial organization of transmembrane tumor necrosis factor (TNF) receptors has been implied as a regulator of cellular fate. Accordingly, molecular tools that can induce specific arrangements of these receptors on cell surfaces would give us an opportunity to study these effects in detail. To achieve this, we introduce DNA origami nanostructures, that precisely scaffold the patterning of TNF-related apoptosis-inducing ligand (TRAIL)-mimicking peptides at nanoscale level. Stimulating human breast cancer cells with these patterns, we find that around 5 nm is the critical inter-ligand distance of hexagonally patterned peptides to induce death receptor clustering and a resulting apoptosis. We thus offer a strategy to reverse the non-efficacy of current ligand- and antibody-based methods for TNF superfamily (TNFRSF) activation.

bioengineering↗

The geometric determinants of programmed antibody migration and binding on multi-antigen substrates

Viruses and bacteria commonly exhibit spatial repetition of surface molecules that directly interface with the host immune system. However the complex interaction of patterned surfaces with multivalent immune molecules such as immunoglobulins and B-cell receptors is poorly understood, and standard characterization typically emphasizes the monovalent affinity. We developed a mechanistic model of multivalent antibody-antigen interactions as well as a pipeline for constructing such models from a minimal dataset of patterned surface plasmon resonance experiments in which antigen pattern geometries are precisely defined using DNA origami nanostructures. We modeled the change in binding enhancement due to multivalence and spatial tolerance,i.e. the strain-dependent interconversion of bound antibodies from monovalently bound to bivalently bound states at varying antigen separation distances. The parameterized model enables mechanistic post hoc characterization of binding behavior in patterned surface plasmon resonance experiments as well as de novo simulation of transient dynamics and equilibrium properties of arbitrary pattern geometries. Simulation on lattices shows that antigen spacing is a spatial control parameter that can be tuned to determine antibody residence time and migration speed. We found that gradients in antigen spacing are predicted to drive persistent, directed antibody migration toward favorable spacing. These results indicate that antigen pattern geometry can influence antibody interactions, a phenomenon that could be significant during the coevolution of pathogens and immunity in processes like pathogen neutralization or affinity maturation.

biophysics↗