Houser, S. R. | bioRxiv Science

bioRxiv2024

Thyroid Hormone Suppresses Medulloblastoma Progression Through Promoting Terminal Differentiation of Tumor Cells

Hypothyroidism is commonly detected in patients with medulloblastoma (MB). A possible link between thyroid hormone (TH) signaling and MB pathogenicity has not been reported. Here, we find that TH plays a critical role in promoting tumor cell differentiation. Reduction in TH levels frees the TH receptor, TR1, to bind to EZH2 and repress expression of NeuroD1, a transcription factor that drives tumor cell differentiation. Increased TH reverses EZH2-mediated repression of NeuroD1 by abrogating the binding of EZH2 and TR1, thereby stimulating tumor cell differentiation and reducing MB growth. Importantly, TH-induced differentiation of tumor cells is not restricted by the molecular subgroup of MB. These findings establish an unprecedented association between TH signaling and MB pathogenicity, providing solid evidence for TH as a promising modality for MB treatment.

cancer biology↗

bioRxiv2019

Abcg2-Expressing Side Population Cells Contribute to Cardiomyocyte Renewal through Fusion

The adult mammalian heart has a limited regenerative capacity. Therefore, identification of endogenous cells and mechanisms that contribute to cardiac regeneration is essential for the development of targeted regenerative therapies. The side population (SP) phenotype enriches for stem cells throughout the body, and SP cells have been identified in the heart. We generated a novel Abcg2-driven, genetic lineage-tracing mouse model and show efficient labeling of SP cells. Labeled SP cells give rise to terminally differentiated cells in bone marrow and intestines. In the heart, we find that Abcg2-expressing SP cells contribute to cardiomyocyte labeling, which is further enhanced in response to different forms of cardiac injury. We find that cardiac SP cells fuse with preexisting cardiomyocytes, which stimulates cardiomyocyte cell cycle entry and likely proliferation, instead of directly differentiating into cardiomyocytes. Our findings provide evidence that cardiac SP cells contribute to endogenous cardiac regeneration through cardiomyocyte fusion.

cell biology↗