Postnatal Abrogation of VEGFR2 Blocks Terminal Cap2 Differentiation by Preventing the Developmental Progression from...

Area of Science:

• Pulmonary vascular biology
• Cellular differentiation
• Developmental biology

Background:

• Lung capillaries consist of proliferative Cap1 and gas-exchange Cap2 subsets.
• Mechanisms of capillary speciation and developmental plasticity are not fully understood.
• Alveolarization is critical for postnatal lung development and gas exchange.

Purpose of the Study:

• Investigate the molecular mechanisms of lung capillary differentiation post-birth.
• Identify the role of VEGFR2 and ERG in capillary speciation.
• Explore therapeutic targets for lung diseases affecting alveolarization.

Main Methods:

• Single-cell transcriptomics and ATAC-sequencing in mouse models.
• Genetic lineage tracing and inducible gene deletion (VEGFR2).
• Analysis of developing human and mouse lungs, including hyperoxia-induced lung injury models.

Main Results:

• Capillary subset 2 (Cap2) cells emerge and expand after birth.
• Capillary subset 1 (Cap1) progenitors transition through an intermediate state (Cap^INT) with high proliferation.
• VEGFR2 is essential for Cap^INT to Cap2 differentiation and proper alveolarization; its abrogation increases Cap^INT cells and impairs lung development.
• ERG is identified as a potential downstream mediator of VEGFR2 signaling in Cap^INT to Cap2 differentiation.

Conclusions:

• Lung capillary differentiation is a stepwise process involving an intermediate cell state.
• VEGFR2 signaling is critical for the second step of differentiation and lung development.
• Dysregulation of this process, particularly the Cap^INT state, is implicated in bronchopulmonary dysplasia (BPD).
• Targeting the Cap1-Cap^INT transition may offer novel therapeutic strategies for BPD and other lung diseases.