Simultaneous Induction of Vasculature and Neuronal Network Formation on a Chip Reveals a Dynamic Interrelationship between Cell Types

While the vascular network provides oxygen, nutrients, and signaling molecules to tissues, neuronal networks receive and deliver information to regulate bodily functions. Thus, they form two vital network systems in the human body, which also align and reciprocally communicate with one another. These neurovascular interactions are vital for both tissue development and maintaining homeostasis.
There is a need for more relevant neurovascular in vitro models to study these interactions in more detailed manner. The current used in vitro neurovascular models are typically established as short-term (≤7 days) culture models, and they miss the supporting vascular mural cells1,2.
In this study, human induced pluripotent stem cell (hiPSC) -derived neurons, fluorescence tagged human umbilical vein endothelial cells (HUVECs), and either human bone marrow or adipose stem/stromal cells (BMSCs or ASCs) as the mural cell types3 were utilized to create a novel 3D neurovascular network-on-chip model. Collagen–fibrin hydrogel was used to establish long-term (≥14
days) 3D cell culture in a microphysiological environment.
Medium optimization revealed that aprotinin-supplemented endothelial cell growth medium-2 (EGM-2) supported the simultaneous formation of neurovascular networks, mural cell properties, and the stability of the hydrogel. Both neuronal and vascular networks that formed were also morphologically
and functionally characterized. Results revealed that vasculature formation was supported by the
neuronal networks by forming direct cell contacts and drastically increasing the secretion of angiogenesis-related factors in multicultures in contrast to cocultures without neurons. Both mural cell types utilized in the study supported the formation of neurovascular networks; however, the BMSCs seemed to enhance the neurovascular networks to greater extent.
Here, we provide a novel human neurovascular network-on-chip platform that is applicable for creating in vivo-like tissue models with intrinsic crosstalk between the cell types. This 3D neurovascular network model forms an initial tool for developing vascularized and innervated organ-on-chip and further body-on-chip concepts and offers the possibility for mechanistic studies on neurovascular interactions.

References
[1] Osaki, T., Sivathanu, V. & Kamm, R.D. Sci Rep. 8, 1 (2018)
[2] Bang, S., Lee, SR. et al. Sci Rep. 7, 8083 (2017).
[3] Mykuliak A, Yrjänäinen A et al. Front Bioeng Biotechnol. 10, 1 (2022)