By contrast, PPE-treated mice with exogenously added Gal-9 showed significant inhibition of emphysema (Fig 1D) and a significantly smaller Lm (66.07 ± 3.27 μm; n = 10) than that of PPE-treated control mice, with a significant increase in alveoli number (Fig 1E). Here, LGALS9 is linked to pulmonary emphysema.