Implantation of engineered human microvasculature to study human infectious diseases in mouse models

Multiscale Imaging to Monitor Functional SHED-Supported Engineered Vessels

Regeneration of orofacial tissues is hampered by the lack of adequate vascular supply. Implantation of in vitro engineered, prevascularized constructs has emerged as a strategy to allow the rapid vascularization of the entire graft. Given the angiogenic properties of dental pulp stem cells, we hereby established a preclinical model of prevascularized constructs loaded with stem cells from human exfoliating deciduous teeth (SHED) in a 3-dimensional-printed material and provided a functional analysis of their in vivo angiogenesis, vascular perfusion, and permeability. Three different cell-loaded collagen hydrogels (SHED-human umbilical vein endothelial cell [HUVEC], HUVEC with SHED-conditioned medium, and SHED alone) were cast in polylactic acid (PLA) grids and ectopically implanted in athymic mice. At day 10, in vivo positron emission tomography (PETscan) revealed a significantly increased uptake of radiotracer targeting activated endothelial cells in the SHED-HUVEC group compared to the other groups. At day 30, ex vivo micro-computed tomography imaging confirmed that SHED-HUVEC constructs had a significantly increased vascular volume compared to the other ones. Injection of species-specific lectins analyzed by 2-photon microscopy demonstrated blood perfusion of the engineered human vessels in both prevascularized groups. However, in vivo quantification showed increased vessel density in the SHED-HUVEC group. In addition, coinjection of fluorescent lectin and dextran revealed that prevascularization with SHED prevented vascular leakage, demonstrating the active role of SHED in the maturation of human-engineered microvascular networks. This preclinical study introduces a novel PLA prevascularized and implantable construct, along with an array of imaging techniques, to validate the ability of SHED to promote functional human-engineered vessels, further highlighting the interest of SHED for orofacial tissue engineering. Furthermore, this study validates the use of PETscan for the early detection of in vivo angiogenesis, which may be applied in the clinic to monitor the performance of prevascularized grafts.

Microfluidic model of the alternative vasculature in neuroblastoma

Neuroblastoma (NB) is a highly vascularized pediatric tumor arising from undifferentiated neural crest cells early in life, exhibiting both traditional endothelial-cell-driven vasculature and an intriguing alternative vasculature. The alternative vasculature can arise from cancer cells undergoing transdifferentiation into tumor-derived endothelial cells (TEC), a trait associated with drug resistance and tumor relapse. The lack of effective treatments targeting NB vasculature primarily arises from the challenge of establishing predictive in vitro models that faithfully replicate the alternative vasculature phenomenon. In this study, we aim to recreate the intricate vascular system of NB in an in vitro context, encompassing both types of vascularization, by developing a novel neuroblastoma-on-a-chip model. We designed a collagen I/fibrin-based hydrogel closely mirroring NB's physiological composition and tumor stiffness. This biomaterial created a supportive environment for the viability of NB and endothelial cells. Implementing a physiological shear stress value, aligned with the observed range in arteries and capillaries, within the microfluidic chip facilitated the successful development of vessel-like structures and triggered transdifferentiation of NB cells into TECs. The vascularized neuroblastoma-on-a-chip model introduced here presents a promising and complementary strategy to animal-based research with a significant capacity for delving into NB tumor biology and vascular targeting therapy.

Supplementary Information

The online version contains supplementary material available at 10.1007/s44164-023-00064-x.

Airway environment drives the selection of quorum sensing mutants and promote Staphylococcus aureus chronic lifestyle

Staphylococcus aureus is a predominant cause of chronic lung infections. While the airway environment is rich in highly sialylated mucins, the interaction of S. aureus with sialic acid is poorly characterized. Using S. aureus USA300 as well as clinical isolates, we demonstrate that quorum-sensing dysfunction, a hallmark of S. aureus adaptation, correlates with a greater ability to consume free sialic acid, providing a growth advantage in an air-liquid interface model and in vivo. Furthermore, RNA-seq experiment reveals that free sialic acid triggers transcriptional reprogramming promoting S. aureus chronic lifestyle. To support the clinical relevance of our results, we show the co-occurrence of S. aureus, sialidase-producing microbiota and free sialic acid in the airway of patients with cystic fibrosis. Our findings suggest a dual role for sialic acid in S. aureus airway infection, triggering virulence reprogramming and driving S. aureus adaptive strategies through the selection of quorum-sensing dysfunctional strains.