# Multifactorial environmental inhibition of Sonic hedgehog signaling: Impact of chemical interactions on pathway activity and craniofacial development

> **NIH NIH F31** · UNIVERSITY OF WISCONSIN-MADISON · 2022 · $34,945

## Abstract

PROJECT SUMMARY
Birth defects cause tremendous individual, familial, and societal burdens, and the development of targeted
prevention strategies has been stymied by biological and etiological complexity. Exemplary of multifactorial
birth defects thought to be substantially modulated by the environment are orofacial clefts (OFCs) and
holoprosencephaly (HPE), common human malformations of the face and brain. The pathogenesis of both
OFCs and HPE is directly linked to embryonic disruption of Sonic hedgehog (Shh) signaling in animal models,
supporting a pathway-based investigation of environmental contributions to birth defect etiology. That Shh
signaling comprises a multi-step process inherently sensitive to modulation across multiple steps of its
signaling cascade makes the pathway especially germane for examining the impact of co-exposures on
etiologically complex, multifactorial disease. The studies proposed in this application are designed to test the
central hypothesis that structurally diverse Shh inhibitors synergistically interact to reduce pathway activity at
the cellular level and exacerbate Shh-associated craniofacial malformations. To test this hypothesis, I have
leveraged NIEHS- and EPA-supported high-throughput chemical screens to create a prioritized list of
environmentally relevant, putative Shh pathway disruptors and developed a novel Shh pathway-complete cell
culture system that is sensitive to inhibition throughout the Shh pathway. I will utilize this system and other
mechanism-based in vitro assays to validate bona fide pathway antagonists, delineate molecular targets within
the Shh pathway, and evaluate additive and synergistic interactions resulting from co-exposure to compounds
with diverse pathway targets. The developmental toxicity of these compounds will then be examined, both
individually and in combination, by targeting dose administration to critical periods of Shh pathway activity
during craniofacial development. The known Shh antagonists cyclopamine, vismodegib, and piperonyl
butoxide will be used throughout the proposed studies as positive controls for pathway-specific effects. These
rigorously designed experiments are expected to reveal environmental factors that adversely impact
development and elucidate mechanisms of Shh pathway disruption that promote synergistic interactions. In
completing the proposed studies, the applicant’s professional development will be advanced through the
establishment of proficiency in experimental design, evaluating the toxicity of mixtures, utilizing animal
models of developmental toxicology, and effectively communicating scientific concepts and results. These
works will also facilitate the applicant’s goal of becoming an independent investigator at a government agency
within the United States.

## Key facts

- **NIH application ID:** 10535719
- **Project number:** 1F31ES034632-01
- **Recipient organization:** UNIVERSITY OF WISCONSIN-MADISON
- **Principal Investigator:** Tyler George Beames
- **Activity code:** F31 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $34,945
- **Award type:** 1
- **Project period:** 2022-09-01 → 2025-08-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10535719

## Citation

> US National Institutes of Health, RePORTER application 10535719, Multifactorial environmental inhibition of Sonic hedgehog signaling: Impact of chemical interactions on pathway activity and craniofacial development (1F31ES034632-01). Retrieved via AI Analytics 2026-05-25 from https://api.ai-analytics.org/grant/nih/10535719. Licensed CC0.

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