Led by Professor Atsushi Iwama of The University of Tokyo, alongside collaborators from St. Jude Children’s Research Hospital and Nissan Chemical Corporation, the multi-institutional team employed genetically engineered mouse models to dissect YAP/TAZ’s role across BM niche cell types. Their findings, published in Blood (June 22, 2026), demonstrate that YAP/TAZ in MSCs is indispensable for maintaining HSC retention under normal conditions. Mice lacking YAP/TAZ specifically in MSCs exhibited a marked decrease in BM HSC numbers with increased stem cell egress into circulation.

Importantly, YAP/TAZ loss in MSCs impeded hematopoietic recovery after radiation injury, revealing its critical role in regenerative hematopoiesis. Concurrently, YAP/TAZ depletion in ECs caused abnormal dilation of BM blood vessels post-injury, underscoring their cooperative function in niche remodeling. Mechanistically, YAP/TAZ govern transcription factors such as Ebf1 and Ebf3 in MSCs, preserving their identity and enabling secretion of essential hematopoietic and angiogenic factors, including Cxcl12.

Capitalizing on this insight, the team identified GA-003, a small molecule inhibitor of LATS1/2 kinases, which activates YAP/TAZ signaling pharmacologically. Administering GA-003 to irradiated mice significantly enhanced BM niche restoration and hastened hematopoietic regeneration. Furthermore, GA-003 improved outcomes after HSC transplantation and synergized with granulocyte colony-stimulating factor (G-CSF), a standard neutropenia treatment, to boost white blood cell recovery.

This discovery paves the way for a novel therapeutic paradigm that targets the BM microenvironment rather than hematopoietic cells directly. Given the complexity of the niche and its influence on multi-lineage blood cell regeneration, enhancing YAP/TAZ activity offers a potent strategy to overcome current limitations in post-therapy hematopoietic recovery.

Prof. Iwama remarks, “Our study highlights the microenvironment’s central role in regeneration and provides a blueprint for developing niche-targeted therapies. This could revolutionize management of hematopoietic complications associated with chemotherapy, radiotherapy, and stem cell transplantation.”

Beyond hematology, these findings open new avenues in regenerative medicine by emphasizing the crosstalk between tissue niches and stem cell function. Pharmacological activation of YAP/TAZ might inspire therapeutic innovations in various organs, heralding a new era where manipulating the tissue microenvironment accelerates recovery after injury or disease.

Subject of Research: Animals
Article Title: Niche-targeted therapy via YAP/TAZ activation enhances hematopoietic regeneration
News Publication Date: June 2026
References: Uemura et al., Blood, 2026, DOI: 10.1182/blood.2025030831
Image Credits: Prof. Atsushi Iwama, The University of Tokyo; Dr. Taito Nishino, Nissan Chemical Corporation
Keywords: YAP, TAZ, bone marrow niche, hematopoietic stem cells, mesenchymal stromal cells, endothelial cells, hematopoietic regeneration, myelosuppression, GA-003, LATS1/2 kinase inhibitor, hematopoiesis, myeloablative therapy