# The chondrocranium in craniofacial development and disease

> **NIH NIH R01** · PENNSYLVANIA STATE UNIVERSITY, THE · 2021 · $495,785

## Abstract

Most investigations of craniosynostosis focus on the dermatocranium, the second cranial skeleton to form
during embryogenesis that comprises the dermal bones of the cranial vault and facial skeleton. A completely
separate cranial skeleton, the chondrocranium, develops before the dermatocranium to support the embryonic
brain and other sense organs. Historically, the chondrocranium has been studied across the vertebrates and is
recognized as fundamental to craniofacial development, but it is not well known to craniofacial biologists and
has never been studied in the laboratory mouse until now. The chondrocranium is formed of cartilage and
though parts of it ossify endochondrally, other portions begin to degenerate by about embryonic day 15-16 in
the mouse. By careful analysis of whole mount and histological specimens, we have documented the
synchronized deterioration of select chondrocranial elements with the appearance and superimposition of
particular dermal bones of the growing dermatocranium. These observations signal the existence of a
mechanism for the coordinated, localized expansion (dermal bones) and resorption (cartilage) of two
developmentally and evolutionarily separate skeletal systems. Our project, supported by strong preliminary
data of the mouse chondrocranium, is designed to test a central hypothesis: that the chondrocranium serves
as a structural and functional scaffold for the later development of dermatocranial elements including the
formation of cranial vault sutures. Based on the common finding that boundaries between different cell
populations often serve as tissue organizers, we recognize the establishment and maintenance of stable
boundaries that restrict the mixing of different cell populations as critical to proper development, and propose a
research design that interrogates the chondrocranial/dermatocranial boundary as significant to the coordinated
development of the skull. We will interrogate cells at specific sites to determine the processes that function to
maintain the boundaries. Then using the Fgfr2c+/C342Y mouse model for craniosynostosis, we will investigate
relevant chondrocranial/dermatocranial boundaries operative in the development of two craniosynostosis
phenotypes: premature closure of the coronal suture and abnormal growth of the midface. That the
chondrocranium is composed of irregularly shaped cartilages, many of which are short-lived, requires that we
conceive new tools for analysis. We will complete development of an innovative system to dissect and
reconstruct the chondrocranium in silico from micro computed tomography images with tight temporal control,
precisely delineate chondrocranial anatomy in 3D over embryonic time, and establish the role of the
chondrocranium in development of the dermatocranium. Achieving our goals will enrich textbook knowledge of
craniofacial development by defining the role of the chondrocranium in the production of dermatocranial
phenotypes, provide information relative ...

## Key facts

- **NIH application ID:** 10087916
- **Project number:** 5R01DE027677-04
- **Recipient organization:** PENNSYLVANIA STATE UNIVERSITY, THE
- **Principal Investigator:** JOAN Therese RICHTSMEIER
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $495,785
- **Award type:** 5
- **Project period:** 2018-02-01 → 2023-01-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10087916

## Citation

> US National Institutes of Health, RePORTER application 10087916, The chondrocranium in craniofacial development and disease (5R01DE027677-04). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10087916. Licensed CC0.

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