Long-Term Safety and Efficacy of Gene-Pulmonary Macrophage Transplantation Therapy of PAP in Csf2ra−/− Mice
Authors: Paritha Arumugam, Takuji Suzuki, Kenjiro Shima, Cormac McCarthy, Anthony Sallese, Matthew Wessendarp, Yan Ma, Johann Meyer, Diane Black, Claudia Chalk, Brenna Carey, Nico Lachmann, Thomas Moritz, Bruce C. Trapnell
Journal: Molecular Therapy (2019)

Hereditary pulmonary alveolar proteinosis (PAP) is a genetic lung disease characterized by surfactant accumulation and respiratory failure arising from disruption of GM-CSF signaling. While mutations in either CSF2RA or CSF2RB (encoding GM-CSF receptor α or β chains, respectively) can cause PAP, α chain mutations are responsible in most patients. Pulmonary macrophage transplantation (PMT) is a promising new cell therapy in development; however, no studies have evaluated this approach for hereditary PAP (hPAP) caused by Csf2ra mutations. Here, we report on the preclinical safety, tolerability, and efficacy of lentiviral-vector (LV)-mediated Csf2ra expression in macrophages and PMT of gene-corrected macrophages (gene-PMT therapy) in Csf2ra gene-ablated (Csf2ra−/−) mice. Gene-PMT therapy resulted in a stable transgene integration and correction of GM-CSF signaling and functions in Csf2ra−/− macrophages in vitro and in vivo and resulted in engraftment and long-term persistence of gene-corrected macrophages in alveoli; restoration of pulmonary surfactant homeostasis; correction of PAP-specific cytologic, histologic, and biomarker abnormalities; and reduced inflammation associated with disease progression in untreated mice. No adverse consequences of gene-PMT therapy in Csf2ra−/− mice were observed. Results demonstrate that gene-PMT therapy of hPAP in Csf2ra−/− mice was highly efficacious, durable, safe, and well tolerated. Hereditary pulmonary alveolar proteinosis (PAP) is a genetic lung disease characterized by surfactant accumulation and respiratory failure arising from disruption of GM-CSF signaling. While mutations in either CSF2RA or CSF2RB (encoding GM-CSF receptor α or β chains, respectively) can cause PAP, α chain mutations are responsible in most patients. Pulmonary macrophage transplantation (PMT) is a promising new cell therapy in development; however, no studies have evaluated this approach for hereditary PAP (hPAP) caused by Csf2ra mutations. Here, we report on the preclinical safety, tolerability, and efficacy of lentiviral-vector (LV)-mediated Csf2ra expression in macrophages and PMT of gene-corrected macrophages (gene-PMT therapy) in Csf2ra gene-ablated (Csf2ra−/−) mice. Gene-PMT therapy resulted in a stable transgene integration and correction of GM-CSF signaling and functions in Csf2ra−/− macrophages in vitro and in vivo and resulted in engraftment and long-term persistence of gene-corrected macrophages in alveoli; restoration of pulmonary surfactant homeostasis; correction of PAP-specific cytologic, histologic, and biomarker abnormalities; and reduced inflammation associated with disease progression in untreated mice. No adverse consequences of gene-PMT therapy in Csf2ra−/− mice were observed. Results demonstrate that gene-PMT therapy of hPAP in Csf2ra−/− mice was highly efficacious, durable, safe, and well tolerated.