Biology subjects

Kroll, K. T.

Publications and source records attributed to Kroll, K. T..

3 recordsLinked to original sources

bioRxiv2025

Outer Membrane Vesicles Hijack TIM-1 for Cellular Uptake

Outer membrane vesicles (OMVs) are nanoscale proteoliposomes shed by Gram-negative bacteria that mediate host-pathogen interactions and hold promise as platforms for vaccines and targeted drug delivery. Despite their biological and translational significance, the cellular mechanisms governing OMV entry into host cells remain poorly understood. Here, we demonstrate that E. coli OMVs are internalized by epithelial cells via clathrin-mediated, receptor-dependent endocytosis. Using a high-throughput screen of over 1,500 human single-pass transmembrane proteins, we identify T-cell immunoglobulin and mucin-domain 1 (TIM-1) as a strong OMV-binding receptor. Functional validation revealed that TIM-1 overexpression markedly increased OMV uptake, whereas TIM-1 knockout and antibody-mediated blockade significantly impaired internalization across multiple cell lines. Mechanistic studies demonstrate that TIM-1 binds to lipopolysaccharide (LPS) on the OMV surface via its known phosphatidylserine-binding domain. Uptake of OMVs by TIM-1 triggers proinflammatory cytokine production which can be reduced by preventing this interaction. Additionally, OMVs from multiple bacterial species hijack TIM-1 for entry, making it an intriguing antivirulence strategy. Our findings establish TIM-1 as a critical host receptor mediating OMV uptake and provide a novel approach to modulate vesicle-driven pathogenesis and enhance OMV-based therapies.

microbiology↗

bioRxiv2025

Perfusable 3D models of ureteric bud and collecting duct tubules

Recent protocols have emerged to derive ureteric bud (UB) and collecting duct (CD) organoids directly from human induced pluripotent stem cells (hiPSCs). However, these 3D kidney tissues lack biophysical cues from luminal flow and a drainage outlet. To address these limitations, we have created perfusable 3D models of UB and CD tubules. UB organoids are first generated from hiPSCs followed by their dissociation into individual UB cells. Individual UB cells are then seeded onto a 3D perfusable channel embedded within an extracellular matrix composed of fragmented basement membrane matrix and collagen I, where they self-assemble into a confluent monolayer. During in vitro perfusion, these cells exhibit UB-like marker expression over several weeks, during which they undergo budding akin to early branching morphogenesis in developing kidneys. To further promote network formation, UB cells are bioprinted adjacent to a perfusable UB tubule, which form interconnections through luminal fusion. Finally, these 3D perfusable UB tubules are differentiated into collecting duct tubules under luminal flow. Our platform facilitates fundamental understanding of human collecting duct formation during renal development, while paving the way for using these physiologically relevant models for drug testing, disease modeling, and, ultimately, integration into bioprinted kidney tissues for therapeutic use.

bioengineering↗

bioRxiv2024

Embedding biomimetic vascular networks via coaxial sacrificial writing into functional tissue

Printing human tissue constructs replete with biomimetic vascular networks is of growing interest for tissue and organ engineering. While it is now possible to embed perfusable channels within acellular and densely cellular matrices, they lack either the branching or multilayer architecture of native vessels. Here, we report a generalizable method for printing hierarchical branching vascular networks within soft and living matrices. We embed biomimetic vessels into granular hydrogel matrices via coaxial embedded printing (co-EMB3DP) as well as into bulk cardiac tissues via coaxial sacrificial writing into functional tissues (co-SWIFT). Each method relies on an extended core-shell printhead that promote facile interconnections between printed branching vessels. Though careful optimization of multiple core-shell inks and matrices, we show that embedded biomimetic vessels can be coaxially printed, which possess a smooth muscle cell-laden shell that surrounds perfusable lumens. Upon seeding these vessels with a confluent layer of endothelial cells, they exhibit good barrier function. As a final demonstration, we construct biomimetic vascularized cardiac tissues composed of a densely cellular matrix of cardiac spheroids derived from human induced pluripotent stem cells. Importantly, these co-SWIFT cardiac tissues mature under perfusion, beat synchronously, and exhibit a cardio-effective drug response in vitro. This advance opens new avenues for the scalable biomanufacturing of organ-specific tissues for drug testing, disease modeling, and therapeutic use.

bioengineering↗