Biology subjects

Tsimbouri, M. P.

Publications and source records attributed to Tsimbouri, M. P..

3 recordsLinked to original sources

bioRxiv2025

Bioengineered bone marrows that can support stem cells and remodel to mimic human disease metabolism and chemotherapeutic effects

Blood cancer drug discovery is reliant on poorly predictive and costly animal models. Therefore, bioengineered, human cell containing, models are attractive to Pharma. Designing effective bone marrow (BM) models is complicated as they need to both regulate haematopoietic stem cell (HSC) phenotype and be able to undergo remodelling to mimic the blood cancer microenvironment. Here, we develop synthetic hybrid niches using poly(ethylacrylate) to organise laminin on hard, bone mimicking, surfaces and interface with soft, marrow mimicking, polyethylene glycol-fibronectin hydrogels. Optimisation of mesenchymal stromal cell (MSC) mechanobiology within the model offers both support for HSCs and remodelling in response to acute myeloid leukaemia derived cells. The remodelling has many parallels to in vivo and patient data including increased dependency on nestin+ve MSCs, enhanced cytoprotection and increased taurine metabolism. We also use the model to demonstrate, as has been seen in vivo, that targeting taurine enhances effects of chemotherapy.

bioengineering↗

bioRxiv2025

Synthetic peptide hydrogels as a model of the bone marrow niche demonstrate efficacy of a combined CRISPR-CAR T-cell therapy for acute myeloid leukaemia

Leukaemias, driven by mutations in hematopoietic stem cells (HSCs), rely on interactions with the bone marrow (BM) niche and other cell populations such as mesenchymal stromal cells (MSCs) for growth and survival. While chimeric antigen receptor (CAR) T-cell therapy shows promise for other hematological malignancies, its application to acute myeloid leukaemia (AML) is hindered by tumour heterogeneity and off-target toxicity. Combining CRISPR-Cas9 gene editing with CAR T-cell therapy has potential for selectively targeting AML cells while sparing healthy tissue. However, validating the efficacy of these treatments prior to clinical trial is hampered by the differences between humans and animal models typically used for pre-clinical testing. Furthermore, traditional in vitro models fail to replicate the complexity of the BM niche and often overestimate treatments efficacy. Here, we present a bioengineered human-cell containing BM niche model combining a fibronectin-presenting polymeric surface and a synthetic peptide hydrogel (PeptiGel) that mimics native BM tissues mechanical properties. This platform supports niche phenotypes in MSCs and HSCs and enables the evaluation of combined CRISPR-CAR T-cell therapy, demonstrating potential as a preclinical human model for testing novel therapies.

bioengineering↗

bioRxiv2019

Design, construction and characterisation of a novel nanovibrational bioreactor and cultureware for osteogenesis

In regenerative medicine, techniques which control stem cell lineage commitment are a rapidly expanding field of interest. Recently, nanoscale mechanical stimulation of mesenchymal stem cells (MSCs) has been shown to activate mechanotransduction pathways stimulating osteogenesis in 2D and 3D culture. This has the potential to revolutionise bone graft procedures by creating cellular graft material from autologous or allogeneic sources of MSCs without using chemical induction. With the increased interest in mechanical stimulation of cells and huge potential for clinical use, it is apparent that researchers and clinicians require a scalable bioreactor system that provides consistently reproducible results with a simple turnkey approach. A novel bioreactor system is presented that consists of: a bioreactor vibration plate, calibrated and optimised for nanometre vibrations at 1 kHz, a power supply unit, which supplies a 1 kHz sine wave signal necessary to generate approximately 30 nm of vibration amplitude, and custom 6-well cultureware with toroidal shaped magnets incorporated in the base of each well for conformal attachment to the bioreactors magnetic vibration plate. The cultureware and vibration plate were designed using finite element analysis to determine the modal and harmonic responses, and validated by interferometric measurement. This helps ensure that the vibration plate and cultureware, and thus collagen and MSCs, all move as a rigid body, avoiding large deformations close to the resonant frequency of the vibration plate and vibration damping beyond the resonance. Assessment of osteogenic protein expression was performed to confirm differentiation of MSCs after initial biological experiments with the system, as well as atomic force microscopy of the 3D gel constructs during vibrational stimulation to verify that strain hardening of the gel did not occur. This shows that cell differentiation was the result of the nanovibrational stimulation provided by the bioreactor alone, and that other cell differentiating factors, such as stiffening of the collagen gel, did not contribute.

cell biology↗