Transient Transfection of the Respiratory Epithelium with Gamma Interferon for Host-Directed Therapy in Pulmonary Tuberculosis

• Published in: Molecular therapy. Nucleic acids 2020-12, Vol.22, p.1121-1128
• Main Authors: Bharti, Reena, Srivastava, Ashish, Roy, Trisha, Verma, Khushboo, Reddy, D.V. Siva, Shafi, Hasham, Verma, Sonia, Raman, Sunil K., Singh, Amit K., Singh, Jyotsna, Ray, Lipika, Misra, Amit
• Format: Article
• Language: English
• Subjects: dry powder inhalation; gamma interferon; gene delivery; gene therapy; host-directed therapy; Original; preclinical proof of concept; pulmonary tuberculosis
• ISSN: 2162-2531; 2162-2531
• DOI: 10.1016/j.omtn.2020.10.023

Nebulized gamma interferon (IFN-γ) protein has been studied for clinical safety and efficacy against pulmonary tuberculosis (TB). The protein is expensive, requires a cold chain, and is difficult to deploy in limited-resource, high-incidence settings. We generated a preclinical proof of concept (PoC) for a dry powder inhalation (DPI) containing DNA constructs to transiently transfect the lung and airway epithelium of mice with murine IFN-γ. Bacterial colony-forming units (CFU) in the lungs of mice infected with Mycobacterium tuberculosis (Mtb) reduced from about 106/g of tissue to ~104 after four doses given once a week. Nodular inflammatory lesions in the lungs reduced significantly in number. Immunohistochemistry of infected lung sections for LC3-1 and LAMP-1 indicated autophagy induction between 18 and 48 h after inhalation. ELISA on bronchoalveolar lavage (BAL) fluid showed differences in kinetics of IFN-γ concentrations in the epithelial lining fluid of healthy versus infected mice. Uninfected mice receiving DNA constructs expressing a fluorescent protein were live-imaged. The fluorescence signals from the intracellular protein peaked at about 36 h after inhalation and declined by 48 h. These results establish preclinical PoC of the efficacy of a DPI and dosing regimen as a host-directed and transient gene therapy of experimental pulmonary TB in mice, justifying preclinical development. [Display omitted] Misra and colleagues present a preclinical proof of concept that transiently transfecting the lung epithelium by means of inhaled DNA encoding gamma interferon is efficacious in treating mice infected with Mycobacterium tuberculosis. They argue that their non-sterile, non-invasive, and potentially storage-stable dry powder inhalation formulation of plasmid DNA has advantages over nebulized protein.