A150 DEVELOPMENT OF MIMETIC MATRICES AS INSTRUCTIVE ORGANOIDS MICROENVIRONMENT FOR THE STUDY OF COLONIC DISEASES
Bibliographic record
Abstract
Abstract Background The functional complexity of the colonic epithelium is dependent on its interaction with the microenvironment involving gradients of soluble factors, extracellular matrix (ECM) proteins and stiffness. The influence of dynamic changes in the ECM has been observed in tumours, with variations in protein expression and rigidity. Their biomolecular impacts on epithelial cell behaviour are less studied due to the structural complexity of the matrix. Organoids offers a novel approach for the study of ECM biodynamics, as they require a matrix (Matrigel) to develop. Previous work showed that it is possible to grow organoids in hydrogels other than Matrigel. To evaluate the effect of matrix composition alteration on cancer initiation, we developed biofunctionalized composite hydrogels that mimic the ECM changes (chemical and physical) observed in the BmpR1a-deficient telocytes Foxl1 + (Bmpr1a△Foxl1+) mouse model of colorectal cancer (CRC) initiation. Aims The development of mimetic matrices, in association with organoids, would enable us to uncover the impact of matrix deregulation on colonic cells behaviour in pathogenesis process. Methods These hydrogels were made of alginate and 8-arm polyethylene glycol- vinyl sulfone (PEG) macromers bearing cysteine residues (CYS) and peptides. Four peptides derived from fibronectin, laminin 111, collagen I and collagen IV were used to mimic the ECM changes in the Bmpr1a△Foxl1+ colon. The grafting of CYS on alginate or peptides on PEG macromers was first characterized by thiol quantification assays. The non-grafted peptides were also analysed by uHPLC. Stiffness of the hydrogels was then determined by dynamic mechanical analysis. Finally, normal mouse organoids were seeded on hydrogels and evaluated for survival by live/dead labeling and proliferation by Alamar blue assays. Matrigel was used as a control. Results Chemical characterization revealed that CYS were grafted onto the alginate chain at around 190 μmol/g alginate. The PEG macromers were functionalized with four peptides at concentration varying from 0.25 to 1.5 mM. Rigidity of the hydrogels depends on the concentration of alginate used where lower concentration leads to soft matrix (0.5 kPa, homeostasis) and high concentration produced a stiff matrix (4 kPa, diseased). Organoids seeded in these mimetic composite hydrogels survived and proliferated in comparison to alginate alone. Conclusions Our results indicate that we can develop mimetic composite hydrogels where colon organoids can survive and thrive. This is a breakthrough model for defining the roles of ECM mechanical and biochemical stimuli in epithelial behaviour during the initiation and development of CRC. Funding Agencies CIHR
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".