Biology subjects

Winkeljann, B.

Publications and source records attributed to Winkeljann, B..

3 recordsLinked to original sources

bioRxiv2026

Proton sponge or membrane fusion? Endosomal escape of siRNA polyplexes illuminated by molecular dynamics simulations

To achieve a therapeutic effect, nanoparticles delivering nucleic acids must facilitate endosomal escape (EE) of their cargo. Despite extensive research, the mechanisms that lead to an effective EE are not sufficiently understood. Herein, we utilized Molecular Dynamics (MD) simulations in All Atom (AA) and Coarse Grained (CG) resolutions to differentiate the interaction of four polymeric formulations (polyplexes) and one lipid nanoparticle (LNP) with endosomal membranes. On the one hand, the results emphasize the benefit of hydrophobic residues in the nanoparticles. On the other hand, the role of anionic lipids in the biological membranes is demonstrated. Furthermore, the identified interaction patterns were successfully correlated to the in vitro performance of the formulations. For the first time, different EE mechanisms of polyplex formulations are visualized in simulation and therefore distinguishable from one another. Hence, this work highlights the power of MD simulations for taking a big step towards better understanding EE efficiency. TOC O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=107 SRC="FIGDIR/small/711661v1_ufig1.gif" ALT="Figure 1"> View larger version (44K): org.highwire.dtl.DTLVardef@1d993forg.highwire.dtl.DTLVardef@1381f29org.highwire.dtl.DTLVardef@185faeborg.highwire.dtl.DTLVardef@11c8524_HPS_FORMAT_FIGEXP M_FIG C_FIG

bioengineering↗

bioRxiv2019

Mucin hydrogel glyco-modulation to investigate immune activity of mucin glycans

Mucins are multifunctional glycosylated proteins that are increasingly investigated as building blocks of novel biomaterials. Once assembled into hydrogels (Muc gels), mucins were shown to modulate the recruitment and activation of immune cells and avoid fibrous encapsulation in vivo. However, nothing is known about the early immune response to Muc gels. This study characterizes the response of macrophages, important orchestrators of the material-mediated immune response, over the first 7 days in contact with Muc gels. The role of mucin-bound sialic acid sugar residues was investigated by first enzymatically cleaving the sugar, then assembling the mucin variants into covalently crosslinked hydrogels with rheological and surface nanomechanical properties similar to non-modified Muc gels. Results with THP1 and human primary peripheral blood monocytes-derived macrophages were strikingly consistent and showed that Muc gels transiently activate the expression of both pro-inflammatory and anti-inflammatory cytokines and cell surface markers, with a maximum on the first day and loss of the effect after 7 days. The activation was sialic acid-dependent for a majority of the markers followed. The pattern of gene expression, protein expression, and functional measurements did not strictly correspond to M1 or M2 macrophage phenotypes. This study highlights the complex early events in macrophage activation in contact with mucin materials and the importance of sialic acid residues in such a response. The enzymatic glyco-modulation of Muc gels appears as a useful tool to help understand the biological functions of specific glycans on mucins which can further inform on their use in various biomedical applications.

bioengineering↗

bioRxiv2019

Immune-informed mucin hydrogels evade fibrotic foreign body response in vivo

The immune-mediated foreign body response to biomaterial implants can trigger the formation of insulating fibrotic capsules that can compromise implant function. To address this challenge, we leverage the intrinsic bioactivity of the mucin biopolymer, a heavily glycosylated protein that forms the protective mucus gel covering mucosal epithelia. By using a bioorthogonal inverse electron demand Diels-Alder reaction, we crosslink mucins into implantable hydrogels. We show that mucin hydrogels (Muc-gels) modulate the immune response driving biomaterial-induced fibrosis. Muc-gels did not elicit fibrosis 21 days after implantation in the peritoneal cavity of C57Bl/6 mice, whereas medical-grade alginate hydrogels (Alg-gels) were covered by fibrous tissues. Further, Muc-gels dampened the recruitment of innate and adaptive immune cells to the gel and triggered a pattern of very mild activation marked by a noticeably low expression of the fibrosis-stimulating TGF-{beta}1 cytokine. With this advance in mucin materials, we provide an essential tool to better understand mucin bioactivities and to initiate the development of new mucin-based and mucin-inspired immune-informed materials for implantable devices subject to fibrotic encapsulation.

bioengineering↗