Project Overview
“Vascular pathology, such as loss of neurovascular coupling and disruption of the blood-brain barrier (BBB), has been documented in Huntington’s disease (HD). Loss of BBB integrity could lead to altered brain homeostasis and exacerbated neuroinflammation, which would aggravate neurodegenerative processes occurring over the course of HD onset and progression. Therefore, innovative preclinical BBB models are key to identifying
therapeutic candidates and enable the deep investigation of complex disease mechanisms.
Current efforts in the laboratory of Dr. de Rus Jacquet aim to establish a functional and perfusable vascularized organoid, and they are supported by a recent publication (de Rus Jacquet et al. 2023, Nature Communications) of a novel brain-chip model. One limitation of this brain chip is that vascular and brain microfluidic channels are built as two physically separate compartments. However, if the vasculature could freely grow and innervate a
brain organoid, it would enable further investigations of the BBB in a human tissue-like environment. Emerging microfluidic technologies enable the production of blood vessels that actively create new spouts via the process of angiogenesis. Vessel sprouting is then directed, via a gradient of angiogenic molecules, towards a central compartment of the chip (OrganoPlate Graft, Mimetas) that hosts an organoid. With time, the newly formed vessels will invade and irrigate the organoid, thus creating a highly complex and sophisticated model to study homeostatic and HD disease mechanisms.
We hypothesize that engineered vessels can be manipulated to produce angiogenic sprouts directed towards brain organoids located at the center of the microfluidic model. The objective of the summer project is to develop a control and HD-derived brain organoid that supports vascular innervation in the microfluidic platform.
Preliminary data generated in the de Rus Jacquet lab confirmed that HuVEC cells can form blood vessels in the microfluidic plate, and perfusion of a defined cocktail of pro-angiogenic molecules promoted vascular sprouting towards the central organoid chamber of the model. Initial experiments have been conducted to generate brain organoids according to existing protocols, however additional optimization steps are necessary and will be the
focus of the internship. We will build on the laboratory’s current protocols and expertise by (i) producing control and HD BBB cell types from human induced pluripotent stem cells (iPSCs), (ii) combining iPSC astrocytes, neurons and pericytes into an extracellular scaffolding matrix, and (iii) incubating the cell preparation for 72 h to allow for organoid formation. Then, the organoid will be transferred to the microfluidic graft chamber and
placed on the microvascular bed of HuVEC sprouts to enable innervation. Upon vascularization, organoid will be fixed in 4% PFA, flash-frozen and cryosectioned. Sections will be immunolabeled to identify cellular components of the BBB and production of a basal lamina.
We anticipate that this procedure will allow microvascular bed formation and innervation of a brain spheroid. Under these conditions, we expect that glial cells will self-organize to mimic a BBB architecture that includes pericyte coverage of the vessel walls, formation of astrocyte end-feet, and production of a basal lamina. Experiments will be assisted by an experienced laboratory technician.”
Partners and Donors
Huntington Society of Canada
