Probing parathyroid organogenesis to instruct stem cell differentiation strategies - Project Summary The parathyroid glands are essential endocrine organs that regulate calcium and phosphate balance through secretion of parathyroid hormone (PTH). Loss or dysfunction of parathyroid tissue—commonly occurring after thyroid or neck surgery—leads to hypoparathyroidism, a debilitating condition for which current treatments rely on chronic calcium supplementation or hormone replacement. These therapies do not achieve the precise feedback regulation of calcium levels that native parathyroid tissue provides. Stem cell-derived parathyroid cells represent a potentially curative alternative. This project seeks to generate functional parathyroid-like cells from human induced pluripotent stem cells (iPSCs) through directed differentiation informed by principles of developmental biology and organogenesis. Our approach leverages recent progress in guiding iPSCs through definitive endoderm (DE), anterior foregut endoderm (AFE), and pharyngeal endoderm (PE) stages, alongside scRNA-seq data I have collected and analyzed from developing parathyroids to identify strategies to drive specification toward a parathyroid phenotype. In parallel, we will test the inductive capacity of transcription factor modules to forward program stem cells at pluripotent, DE, AFE, and PE stages to parathyroid identity. The differentiation protocol integrates small molecule modulation of key signaling pathways, such as BMP, WNT, and SHH, augmented by transcriptional cues derived from embryonic development. To validate lineage fidelity and functional capacity, we will assess expression of parathyroid-specific markers—including GCM2, PTH, and CASR—as well as calcium-responsive PTH secretion in vitro. Single-cell RNA sequencing will map lineage trajectories and dissect genetic programs governing parathyroid fate decisions. This work is enabled by the collaborative and resource-rich environment at Yale University. The project benefits interdisciplinary supervision of both Dr. Diane S. Krause, a leader in hematopoiesis as well as iPSC to parathyroid differentiation, and Dr. Zachary D. Smith. Together, their labs offer expertise in iPSC culture and parathyroid functional assessment embryonic development, germ layer specification, and embryo manipulation, offering key insight into developmental timing and patterning. Yale's core facilities for stem cell cultivation, flow cytometry, imaging, cluster computing, and high throughput sequencing will further accelerate progress and ensure technical rigor. By bridging stem cell biology with developmental genetics, this project aims to elucidate the regulatory networks that specify parathyroid identity and establish a platform for patient-specific cell therapies. The ultimate goal is to provide an autologous source of transplantable, functional parathyroid tissue to restore calcium homeostasis in individuals with hypoparathyroidism.
