Biology subjects

MACHILLOT, P.

Publications and source records attributed to MACHILLOT, P..

3 recordsLinked to original sources

bioRxiv2021

Differential bioactivity of four BMP-family members as function of biomaterial stiffness

Whereas soft biomaterial is not able to induce cell spreading, BMP-2 presented by a soft film has been described to be sufficient to trigger cell spreading, migration and downstream BMP-2 signaling. Based on thin polyelectrolyte films of controlled stiffness, we investigated whether the presentation of four BMP members (2, 4, 7, 9) in a matrix-bound manner may differentially impact cell adhesion and bone differentiation of skeletal progenitors. We performed high content and automated screening of cellular responses, including cell number, cell spreading area, SMAD phosphorylation and alkaline phosphatase activity. The basolateral presentation of the different BMPs allowed us to discriminate the specificity of cellular response and the role of BMP receptors type I, type II, as well as three {beta} integrins, in a BMP type and stiffness-dependent manner.

cell biology↗

bioRxiv2020

3D printed scaffold combined to 2D osteoinductive coatings to repair a critical-size mandibular bone defect

the reconstruction of large bone defects (12 cm3) remains a challenge for clinicians. We developed a new critical-size mandibular bone defect model on a mini-pig, close to human clinical issues. We analyzed the bone reconstruction obtained by a 3D printed scaffold made of clinical-grade PLA, coated with a polyelectrolyte film delivering an osteogenic bioactive molecule (BMP-2). We compared the results (CT-scan, CT, histology) to the gold standard solution, bone autograft. We demonstrated that the dose of BMP-2 delivered from the scaffold significantly influenced the amount of regenerated bone and the repair kinetics, with a clear BMP-2 dose-dependence. Bone was homogeneously formed inside the scaffold without ectopic bone formation. The bone repair was as good as for the bone autograft. The BMP-2 doses applied in our study were reduced 20 to 75-fold compared to the commercial collagen sponges used in the current clinical applications, without any adverse effects. 3D printed PLA scaffolds loaded with reduced doses of BMP-2 can be a safe and simple solution for large bone defects faced in the clinic.

bioengineering↗

bioRxiv2020

High throughput measurements of BMP/BMP receptors interactions using bio-layer interferometry

Bone morphogenetic proteins (BMP) are an important family of growth factors playing a role in a large number of physiological and pathological processes, including bone homeostasis, tissue regeneration and cancers. In vivo, BMPs bind successively to both BMP receptors (BMPR) of type I and type II, and a promiscuity has been reported. In this study, we used bio-layer interferometry to perform parallel real-time biosensing and to deduce the kinetic parameters (ka, kd) and the equilibrium constant (KD) for a large range of BMPs/BMPR combinations in similar experimental conditions. We selected four members of the BMP family (BMP-2, 4, 7, 9) known for their physiological relevance and studied their interactions with five type-I BMP receptors (ALK1, 2, 3, 5, 6) and three type-II BMP receptors (BMPR-II, ACTR-IIA, ACTR-IIB). We reveal that BMP-2 and BMP-4 behave differently, especially regarding their kinetic interactions and affinities with the type-II BMPR. We found that BMP-7 has a higher affinity for ACTR-IIA and a tenfold lower affinity with the type-I receptors. While BMP-9 has a high and similar affinity for all type-II receptors, it can interact with ALK5 and ALK2, in addition to ALK1. Interestingly, we also found that all BMPs can interact with ALK5. The interaction between BMPs and both type-I and type II receptors immobilized on the same surface did not reveal further cooperativity. Our work provides a synthetic view of the interactions of these BMPs with their receptors and paves the way for future studies on their cell-type and receptor specific signaling pathways.

biophysics↗