# Engineering developmentally-relevant Wnt signaling events to improve iPSC-derived blood-brain barrier models

> **NIH NIH R21** · VANDERBILT UNIVERSITY · 2024 · $237,750

## Abstract

Project summary
Mounting evidence indicates that vascular damage and blood-brain barrier (BBB) dysfunction contribute to the
progression of Alzheimer’s disease and related dementias (ADRDs). However, it remains challenging to study
and understand connections between BBB dysfunction and ADRDs. In vitro BBB models represent valuable
tools for investigating vascular contributions to ADRDs due to higher throughput and ease of manipulation.
Historically, in vitro BBB models were constructed from primary brain microvascular endothelial cells (BMECs)—
the principal functional component of the BBB—but after removal from the brain, BMECs rapidly de-differentiate
and lose BBB-specific properties that are crucial for studying ADRDs. Strategies have been developed to
differentiate human induced pluripotent stem cells (iPSCs) into endothelial cells with BBB attributes, but such
approaches remain imperfect even after a decade of refinement. For example, iPSC-derived cells with a strong
BBB phenotype lack robust endothelial character, but artificial reinforcement of endothelial identity via
transcription factor overexpression completely ablates BBB properties. Conversely, efforts to imbue endothelial
progenitors or mature endothelial cells with a BBB phenotype, through transgene overexpression or small
molecule and growth factor treatments, have been largely ineffective. In vivo, BBB development is driven
specifically by Wnt7a, and this Wnt ligand can only be transduced into active β-catenin signaling when membrane
receptors GPR124 and RECK are present on the endothelium—for example, deletion of Wnt7a, GPR124, or
RECK activity yields defects in BBB and neurovascular development. Given the importance of this pathway for
BBB development, we hypothesize that specific activation of Wnt7 signaling in naïve iPSC-derived endothelial
progenitors will impart representative BBB identity more effectively than prior efforts using generic activation of
Wnt/β-catenin signaling. We will investigate this hypothesis using CRISPR and synthetic biology approaches to
activate Wnt7 signaling in naïve iPSC-derived endothelial progenitors in simple two-dimensional models (Aim 1)
and more complex three-dimensional neurovascular assemblies (Aim 2). Outcomes from this project are
expected to yield improved in vitro human BBB models that are better suited for studying causes and impacts of
vascular disturbance in ADRDs.

## Key facts

- **NIH application ID:** 10900907
- **Project number:** 1R21NS137563-01
- **Recipient organization:** VANDERBILT UNIVERSITY
- **Principal Investigator:** Jonathan Matthew Brunger
- **Activity code:** R21 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $237,750
- **Award type:** 1
- **Project period:** 2024-03-01 → 2026-02-28

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10900907

## Citation

> US National Institutes of Health, RePORTER application 10900907, Engineering developmentally-relevant Wnt signaling events to improve iPSC-derived blood-brain barrier models (1R21NS137563-01). Retrieved via AI Analytics 2026-05-29 from https://api.ai-analytics.org/grant/nih/10900907. Licensed CC0.

---

*[NIH grants dataset](/datasets/nih-grants) · CC0 1.0*