Microparticles induce variable levels of activation in macrophages infected with Mycobacterium tuberculosis.
Activation of human macrophages infected with Mycobacterium tuberculosis was investigated following exposure to microparticles (MP) possessing high anti-tubercular efficacy in mice. A small set of innate responses (cytokine profiles, NO production, Annexin-V staining and caspase-8, caspase-9 and caspase-3 activities) of differentiated THP-1 cells or human monocyte-derived macrophages infected 1:10 in vitro were compared. Cytokines of THP-1 macrophages were comparable in trends, but not in magnitude, with five human genotypes studied. MP reversed suppression of tumor necrosis factor induced by infection, and transiently upregulated gamma-interferon. Drug-free MP surprisingly induced gamma-interferon, but not tumor necrosis factor. Primary cells responded to MP, regardless of drug content, by upregulation of NO; but THP-1 cells did not respond to drug-free MP. About 19% of infected cells exposed to MP underwent apoptosis compared to approximately 11% cells treated otherwise. Cell death induced by drug-free MP was caspase independent. Intracellular bacterial survival varied between individuals. Untreated infection resulted in survival of 900+/-141 cfu; exposure to soluble drugs, drug-containing and blank microparticles respectively, reduced CFU counts to <10, <10 and 102+/-139. These observations indicate that despite variations in magnitude between cells from different sources, innate responses conducive to killing intracellular bacteria were evoked by inhalable MP.
Yadav
Awadh B
AB
Pharmaceutics Division, Central Drug Research Institute, CSIR, Lucknow, India.
Muttil
Pavan
P
Singh
Amit K
AK
Verma
Rahul K
RK
Mohan
Mradul
M
Agrawal
Atul K
AK
Verma
Ajay S
AS
Sinha
Sudhir K
SK
Misra
Amit
A
D000818:Animals; D017304:Annexin A5 / Q000378:metabolism; D017209:Apoptosis; D020169:Caspases / Q000378:metabolism; D002460:Cell Line; D055252:Cell-Derived Microparticles / Q000276:immunology*; D016207:Cytokines / Q000276:immunology / Q000378:metabolism*; D007371:Interferon-gamma / Q000378:metabolism; D008262:Macrophage Activation / Q000276:immunology*; D008264:Macrophages / Q000382:microbiology*; D051379:Mice; D009169:Mycobacterium tuberculosis / Q000276:immunology / Q000472:pathogenicity; D009569:Nitric Oxide / Q000096:biosynthesis; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism; D015854:Up-Regulation
D017304:Annexin A5; D016207:Cytokines; D014409:Tumor Necrosis Factor-alpha; D009569:Nitric Oxide; D007371:Interferon-gamma; D020169:Caspases