research

Over the course of development, a single fertilized cell gives rise to trillions of cells organized into tissues, organs, and systems — a process that depends on progenitor populations that migrate, change identity, and build structures far from where they originated. Our lab focuses on one of the most important of these populations: the neural crest.

Neural crest cells are multipotent stem cells specific to vertebrate embryos, and they arise from the ectoderm but they don’t play by the ectoderm’s rules. Ectoderm classically gives rise to skin and the nervous system, while structures like bone, cartilage, and smooth muscle generally come from the mesoderm. Neural crest cells break that convention: after undergoing an epithelial-to-mesenchymal transition (EMT), delaminating, and migrating throughout the embryo, they go on to build much of our craniofacial skeleton and other typically-mesodermal tissues, alongside the peripheral nervous system, secretory cells of the adrenal gland, portions of the cardiovascular system, and even the melanocytes in our skin.

Because neural crest cells contribute to so many different structures, disruptions to their formation, migration, or differentiation are responsible for as many as 1 in 3 congenital anomalies — including cleft lip/palate, Hirschsprung disease, Waardenburg syndrome, and cancers such as neuroblastoma. We study normal neural crest development because understanding the normal program is what allows us to recognize, prevent, and eventually treat what happens when it goes wrong.

Neural crest cells undergo a classic EMT and make some of the longest cell migrations in the body, making them a powerful in vivo model for studying EMT and cell migration more generally. Many of the same EMT programs that neural crest cells use during normal development are redeployed by cancer cells during invasion and metastasis. We take advantage of this: our use of developmental and cancer cell model systems in parallel act as natural comparison points to better understand and treat normal development and disease states.

A growing body of work has linked dysregulated lipid metabolism to EMT and metastasis in cancer. We recently found that lipid metabolism is developmentally reprogrammed in neural crest cells as well — some of the same enzymes and lipid species implicated in cancer invasion turn out to be under precise developmental control during normal embryogenesis.

Our first two papers laid the foundation for this idea. We showed that nSMase2 (encoded by SMPD3) is selectively upregulated in the neural crest right at the onset of EMT, where it generates ceramide at the plasma membrane. This local shift in membrane lipid composition drives receptor-mediated endocytosis of cadherins and Wnt/BMP signaling complexes, which in turn activates the pro-EMT transcriptional program (SNAI2, SOX9) and enables migration (Piacentino et al., 2022). We then traced this back to the gene regulatory network controlling it: a SMPD3 enhancer (Enh3) is directly bound by SOX10, with SOX9 acting upstream through SOX10, linking a core neural crest transcription factor circuit directly to a lipid-metabolizing effector gene (Piacentino et al., 2024).

This finding shapes the questions that drive most of our current projects:

• How do developmental gene regulatory networks drive changes in lipid metabolism over time?
• What is the mechanistic role of specific, differentially regulated lipid species in development and disease?
• How does changing lipid content reshape membrane form and function — and how does that, in turn, feed back on cell behavior?

We’re pursuing these questions on multiple fronts, from a project on how the lipid-binding protein ApoD regulates otic placode specification, to differential lipidomic profiling comparing developmental and cancer EMT models. By integrating membrane biochemistry and biophysics — asking how altered lipid composition changes physical membrane properties like fluidity and curvature — with classic cell signaling and migration studies, we take a unique approach toward understanding fundamental questions in neural crest development.

We combine work in the chick embryo (Gallus gallus), our primary in vivo model system, with in vitro studies in cancer cell lines and human pluripotent stem cell-derived organoids and neural crest cells. Chick embryos are experimentally accessible and easily manipulated in ovo, letting us follow neural crest cells from neurulation through early migration with fine spatial and temporal control.

To ask these questions, we use a range of approaches:

• Embryonic microsurgery and electroporation to perturb gene regulatory network components and lipid-metabolizing enzymes directly in the embryo
• Live imaging of EMT and migration in whole mount and ex vivo, using fluorescent labels to track cell movements and biosensors to study molecular pathways of interest
• Lipidomic profiling to identify and track specific lipid species across development and disease
• Membrane biophysical characterization to link lipid composition to physical membrane properties
• Single-cell and bulk sequencing and computational analysis to define the transcriptional programs that regulate neural crest development
• In vitro modeling to test whether mechanisms uncovered in the embryo hold in human cellular contexts

Together, these approaches let us move from gene regulatory network to metabolic enzyme to membrane biophysics to cell behavior — and back to the congenital anomalies and cancers that result when any part of this chain breaks down.