Angpt1, short for angiopoietin-1, is a cytokine crucial for developmental angiogenesis. It functions through the Tie2 receptor, regulating the vascular and hematopoietic systems. The Angpt1-Tie2 signaling pathway plays a vital role in preserving vascular integrity and is involved in multiple biological processes related to angiogenesis and cell differentiation [2].

In a study using conditionally inducible transgenic mice expressing a genetically engineered Angpt1 (COMP-Angpt1), enhanced Angpt1/Tie2 signaling was found to affect the differentiation capacity of hematopoietic lineages during development. Four-week-old Col1a1-Cre+/COMP-Angpt1+ mice had a lower percentage of circulating B cells and a higher percentage of myeloid cells compared to control mice. Also, LSK cells from 8-week-old Col1a1-Cre+/COMP-Angpt1+ mice showed better long-term bone marrow reconstitution ability, indicating increased stem cell activity of HSCs [2]. In lung adenocarcinoma, overexpression and knockout models of CCL28 were used to establish mouse models. It was shown that CCL28 could promote tumor vascular normalization through recruiting and metabolic reprogramming pericytes. Mechanistically, CCL28 modified the retinoic acid (RA) metabolism and increased ANGPT1 expression via RXRα in pericytes, enhancing the stability of endothelial cells [1].

In conclusion, Angpt1 is essential for angiogenesis and has a significant impact on hematopoietic stem cell differentiation and tumor-related vascular processes. Studies using mouse models, such as those with enhanced Angpt1 expression or related gene knockouts, have provided valuable insights into its functions in development and disease, especially in the context of angiogenesis-related diseases like lung adenocarcinoma.