HIV induces airway basal progenitor cells to adopt an inflammatory phenotype

Despite the introduction of anti-retroviral therapy, chronic HIV infection is associated with an increased incidence of other comorbidities such as COPD. Based on the knowledge that binding of HIV to human airway basal stem/progenitor cells (BC) induces a destructive phenotype by increased MMP-9 expression through MAPK signaling pathways, we hypothesized that HIV induces the BC to express inflammatory mediators that contribute to the pathogenesis of emphysema. Our data demonstrate that airway BC isolated from HAART-treated HIV⁺ nonsmokers spontaneously release inflammatory mediators IL-8, IL-1β, ICAM-1 and GM-CSF. Similarly, exposure of normal BC to HIV in vitro up-regulates expression of the same inflammatory mediators. These HIV-BC derived mediators induce migration of alveolar macrophages (AM) and neutrophils and stimulate AM proliferation. This HIV-induced inflammatory phenotype likely contributes to lung inflammation in HIV⁺ individuals and provides explanation for the increased incidence of COPD in HIV⁺ individuals.