title: Treatment of Mycobacterium tuberculosis-Infected Macrophages with Poly(Lactic-Co-Glycolic Acid) Microparticles Drives NFκB and Autophagy Dependent Bacillary Killing.
abstract: The emergence of multiple-drug-resistant tuberculosis (MDR-TB) has pushed our available repertoire of anti-TB therapies to the limit of effectiveness. This has increased the urgency to develop novel treatment modalities, and inhalable microparticle (MP) formulations are a promising option to target the site of infection. We have engineered poly(lactic-co-glycolic acid) (PLGA) MPs which can carry a payload of anti-TB agents, and are successfully taken up by human alveolar macrophages. Even without a drug cargo, MPs can be potent immunogens; yet little is known about how they influence macrophage function in the setting of Mycobacterium tuberculosis (Mtb) infection. To address this issue we infected THP-1 macrophages with Mtb H37Ra or H37Rv and treated with MPs. In controlled experiments we saw a reproducible reduction in bacillary viability when THP-1 macrophages were treated with drug-free MPs. NFκB activity was increased in MP-treated macrophages, although cytokine secretion was unaltered. Confocal microscopy of immortalized murine bone marrow-derived macrophages expressing GFP-tagged LC3 demonstrated induction of autophagy. Inhibition of caspases did not influence the MP-induced restriction of bacillary growth, however, blockade of NFκB or autophagy with pharmacological inhibitors reversed this MP effect on macrophage function. These data support harnessing inhaled PLGA MP-drug delivery systems as an immunotherapeutic in addition to serving as a vehicle for targeted drug delivery. Such "added value" could be exploited in the generation of inhaled vaccines as well as inhaled MDR-TB therapeutics when used as an adjunct to existing treatments.
authors.affiliation: School of Pharmacy, Royal College of Surgeons in Ireland, Dublin 2, Ireland.|Department of Clinical Medicine, Institute of Molecular Medicine, Trinity College Dublin, and St. James' Hospital, Dublin, Ireland.
authors.forename: Ciaran
authors.initials: C
authors.lastname: Lawlor
authors.affiliation: School of Pharmacy, Royal College of Surgeons in Ireland, Dublin 2, Ireland.|Department of Clinical Medicine, Institute of Molecular Medicine, Trinity College Dublin, and St. James' Hospital, Dublin, Ireland.
authors.forename: Gemma
authors.initials: G
authors.lastname: O'Connor
authors.affiliation: Department of Clinical Medicine, Institute of Molecular Medicine, Trinity College Dublin, and St. James' Hospital, Dublin, Ireland.
authors.forename: Seonadh
authors.initials: S
authors.lastname: O'Leary
authors.affiliation: School of Pharmacy, Royal College of Surgeons in Ireland, Dublin 2, Ireland.
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Gallagher
authors.affiliation: School of Pharmacy, Royal College of Surgeons in Ireland, Dublin 2, Ireland.|Trinity Centre for Bioengineering, Trinity College Dublin, Dublin 2, Ireland.
authors.forename: Sally-Ann
authors.initials: SA
authors.lastname: Cryan
authors.affiliation: Department of Clinical Medicine, Institute of Molecular Medicine, Trinity College Dublin, and St. James' Hospital, Dublin, Ireland.
authors.forename: Joseph
authors.initials: J
authors.lastname: Keane
authors.affiliation: Department of Clinical Medicine, Institute of Molecular Medicine, Trinity College Dublin, and St. James' Hospital, Dublin, Ireland.
authors.forename: Mary P
authors.initials: MP
authors.lastname: O'Sullivan
mesh_terms: D000818:Animals; D001343:Autophagy / Q000187:drug effects*; D020169:Caspases / Q000378:metabolism; D016923:Cell Death / Q000187:drug effects / Q000276:immunology; D002460:Cell Line; D016207:Cytokines / Q000096:biosynthesis; D003602:Cytotoxicity, Immunologic / Q000187:drug effects*; D006801:Humans; D019344:Lactic Acid / Q000008:administration & dosage*; D008264:Macrophages / Q000187:drug effects* / Q000382:microbiology* / Q000502:physiology; D051379:Mice; D009169:Mycobacterium tuberculosis / Q000276:immunology*; D016328:NF-kappa B / Q000378:metabolism*; D010587:Phagocytosis; D011100:Polyglycolic Acid / Q000008:administration & dosage*; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer
chemical_list: D016207:Cytokines; D016328:NF-kappa B; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid; D020169:Caspases