# Investigating the mechanisms of a multi-state model of Wnt signaling

> **NIH NIH R01** · ARIZONA STATE UNIVERSITY-TEMPE CAMPUS · 2021 · $293,082

## Abstract

PROJECT SUMMARY ABSTRACT
The WNT signaling pathway regulates numerous developmental processes and plays a critical role in the
maintenance of healthy tissue and cells in adults. Moreover, dysfunction in WNT signaling has been implicated
in numerous developmental disorders, neurodegeneration, and tumorigenesis. Canonical WNT signaling is
typically described as a ‘binary’ system, the so-called ‘two-state’ model. In the ‘off’ state, a protein destruction
complex directs the continual proteolytic degradation of β-catenin. In the ‘on’ state, in the presence of a WNT
ligand, this protein complex is disassembled, allowing β-catenin to accumulate and translocate into the nucleus,
thereby altering gene transcription. However, this model does not fully explain how gradients of WNT signaling
activity that are present during the development and patterning of many tissues lead to precise changes in
transcriptional response and cell identity. In addition, this model does not adequately explain how different WNT
signaling thresholds lead to the manifestation of cancer and other pathological conditions. To better understand
the complex, multifaceted role of WNT signaling in human development and disease, we have engineered an in
vitro human pluripotent stem cell (hPSC)-based model that mimics the same early in vivo developmental effects
of the WNT signaling gradient on the anterior-posterior (A/P) patterning of the neural tube. Using this system we
will test our proposed model and hypothesis that specific levels of WNT activity are translated into precise
transcriptional responses and cell phenotypes through two complementary mechanisms: (i) directly through the
transcriptional regulation of genes related to A/P neural tube patterning and (ii) indirectly through the actions of
the transcriptional repressor SP5. In the first aim of the proposed research, we will use single cell gene
expression analysis, genome-wide expression analysis (RNA-seq), and DNA binding analysis (ChIP-seq) to
define the transcriptional mechanisms by which β-catenin regulates the A/P identity of hPSC-derived neural
cells. In the second aim, we will utilize a series of novel knockdown and overexpression hPSC lines in conjunction
with ChIP-seq analysis to investigate the role of individual TCF/LEF proteins in regulating the regional identity of
hPSC-derived neural cells. Finally, in the third aim, we will use engineered knockout and knockin hPSC lines
along with ChIP-seq to establish SP5 as a mediator of WNT signaling in specifying the A/P regional identity of
hPSC-derived neural cells. Overall, the new insights gained from this research will not only lead to a more
thorough understanding of how WNT signaling regulates early neurodevelopment but also will have significant
impact on our understanding of the role of WNT signaling in disease initiation and progression.

## Key facts

- **NIH application ID:** 10135103
- **Project number:** 5R01GM121698-05
- **Recipient organization:** ARIZONA STATE UNIVERSITY-TEMPE CAMPUS
- **Principal Investigator:** DAVID A BRAFMAN
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $293,082
- **Award type:** 5
- **Project period:** 2017-04-01 → 2023-03-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10135103

## Citation

> US National Institutes of Health, RePORTER application 10135103, Investigating the mechanisms of a multi-state model of Wnt signaling (5R01GM121698-05). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/10135103. Licensed CC0.

---

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