Biology subjects

Giunta, C.

Publications and source records attributed to Giunta, C..

3 recordsLinked to original sources

bioRxiv2026

A Modular Synthetic Hydrogel with Cell-scale Micropores Modulates Osteocyte-like Morphogenesis and Osteogenic Differentiation In Vitro

One crucial step during early osteogenesis is the embedding of osteoblasts within a collagen-rich extracellular matrix (osteoid), where they subsequently differentiate into a functional network of osteocytes. However, reconstructing 3D osteocyte networks in vitro remains a major challenge. We recently developed a synthetic microporous hydrogel to support the in vitro culture of 3D bone cell networks. Although matrix biodegradability facilitates cell-material interactions, the influence of micropores on bone tissue morphogenesis and differentiation remains poorly understood. Here, we investigate the effect of cell-scale micropores on bone cell morphogenesis and osteogenic differentiation in vitro. By exploiting polymerization-induced phase separation (PIPS) between 4-arm polyethylene glycol vinyl sulfones and dextran in the presence of hyaluronan, we generated matrix metalloproteinase-sensitive hydrogels with cell-scale micropores. Increasing the dextran concentration enlarged the average pore size from 4 m to 8 m, accompanied by a slight decrease in mechanical stiffness. Following encapsulation within these hydrogels, primary human osteoblasts remained highly viable. Hydrogels with larger pores supported extensive 3D cell network formation, whereas hydrogels with smaller pores exhibited enhanced osteogenic differentiation following 21 days of osteogenic culture. Together, these findings highlight that bone cells are sensitive to microporous physical cues and even minor changes over pore sizes can make an impact on osteocyte-like morphogenesis and differentiation in vitro.

bioengineering↗

bioRxiv2025

Engineering patient-derived organotypic bone models for skeletal disease and osteoanabolic therapy testing

Bone-forming therapies often fail in genetic skeletal disorders, highlighting critical gaps in mechanistic understanding and therapy evaluation. We developed 3D bioprinted organotypic bone models using primary cells from a patient with FKBP10-related osteogenesis imperfecta (OI) and from metabolically healthy controls obtained via femoral osteotomy (FO). Cyclic me-chanical loading and reseeding generated patient-derived bone-like tissue for structural, molecu-lar, and transcriptomic characterization of the engineered donor-specific tissue material. Dick-kopf-1 antibody (DKK1Ab) was then administered as a therapeutic perturbation. OI constructs showed a bidirectional interferon-stimulated gene (ISG) signature and hypermineralization with structural fragility, hallmark features of OI. Unlike FO constructs, DKK1Ab administration in OI resulted in a limited transcriptional response marked by ISG downregulation and increased MKI67 expression. Therapeutic perturbation with DKK1Ab increased early procollagen I se-cretion, and was associated with lower fracture scores, although the within-OI difference was not statistically significant. This proof-of-concept demonstrates multimodal donor-specific char-acterization of engineered patient-derived bone models following DKK1Ab perturbation.

bioengineering↗

bioRxiv2024

3D-bioprinted patient-specific organotypic bone model mimicking mineralization dysregulation in FKBP10-related osteogenesis imperfecta

Osteogenesis imperfecta (OI) is a heterogeneous group of rare genetic diseases characterized by increased bone fragility and deformities. The pathomechanisms of OI are poorly understood, hindering the development of disease-specific therapy. Addressing the limited understanding of OI and the lack of targeted treatments remains a challenge, given its varied symptoms and large clinical spectrum. Animal models have greatly advanced the understanding of the disease; however, the heterogeneity and subtype-specific symptoms are difficult to translate to humans. In vitro models offer a promising tool for translational medicine, as they have the potential to yield patient-specific insights in a controlled environment using patient derived-cells. We used mechanically loaded 3D-bioprinted patient-specific organotypic bone models and time-lapsed micro-computed tomography to demonstrate dysregulation of mineralization in FKBP10-related OI compared to healthy controls. In contrast to healthy controls, tissue mineral density and stiffness were decoupled, such that hypermineralization observed in OI samples did not lead to increased stiffness. Additionally, we were able to replicate experimental stiffness using sample specific micro-finite element analysis. This allowed us to show mineral formation in regions of high local strain, suggesting mechanoregulation in FKBP10-related OI organotypic bone models is comparable to healthy controls. Regional analysis of mineralization showed increased heterogeneous mineralization, microarchitectural inhomogeneities and scaffold microporosity of OI samples compared to healthy controls. Our results suggest that the observed dysregulation of mineralization is the main driver for the altered mineral-mechanics properties observed in FKBP10-related organotypic bone models. One Sentence SummaryOrganotypic bone models demonstrate dysregulated mineralization in osteogenesis imperfecta samples compared to healthy controls.

bioengineering↗