Conditional Activin Receptor Type 1B (Acvr1b) Knockout Mice Reveal Hair Loss Abnormality

Researchers created mice with a conditional disruption of the activin A receptor type 1b (Acvr1b) to study its role in epithelial tissues. These Acvr1b(flox/flox); K14-Cre mice exhibited varying degrees of hairlessness starting at postnatal day 5, which worsened with age. Histological analyses revealed that hair follicles developed during morphogenesis but were later disrupted due to delays in hair cycle reentry, leading to severe hair loss. Additionally, these mice had a thicker epidermis due to persistent proliferation of skin epithelial cells, though no tumors were observed by 18 months. This study provided direct genetic evidence that Acvr1b signaling was essential for both hair follicle development and cycling.