To determine the role of the SEMA3B-NRP1 axis in preclinical mouse models of pulmonary fibrosis, we quantified the expression of SEMA3B and NRP1 in the lungs of mice with severe fibrotic lung disease in two murine models of pulmonary fibrosis, bleomycin (BLM)-induced, and TGFα-induced lung fibrosis (23, 41). Here, SEMA3B is linked to pulmonary fibrosis.