Induction of heme oxygenase-1 contributes to survival of Mycobacterium abscessus in human macrophages-like THP-1 cells.

Abstract

Mycobacterium abscessus (M.abs) is a rapidly growing mycobacterial species that infects macrophages, and is an important pathogen in patients with cystic fibrosis. We studied the early stages of M.abs infection of macrophages, with emphasis on the role of heme-oxygenase-1 (HO-1) in this infection. THP-1 cells were activated using TPA into macrophage-like cells and infected with M.abs for different time points. M.abs infection robustly induced HO-1 expression in the THP-1 cells. Production of HO-1 was p38 MAPK-dependent, as p38 inhibitors suppressed HO-1 induction. Pretreatment with HO-1 inhibitors tin-protoporphyrin (SnPP) significantly inhibited M.abs growth inside macrophages. Furthermore, inhibiting HO-1 using HO-1 siRNA or the HO-1 upstream signaling molecule; Nrf2 using Nrf2 siRNA resulted in similar inhibition of M.abs. In contrast, inducing HO-1 did not increase M.abs intracellular growth above control. Products of HO-1 metabolism of heme are bilirubin, biliverdin, carbon monoxide (CO) and iron. The addition of either bilirubin or biliverdin, but not CO, completely restored the SnPP inhibitory effect and partially that with HO-1 siRNA. To understand the mechanisms, we used Syto-62 labeled M.abs to infect macrophages. Interestingly, HO-1 inhibition promoted M.abs-containing phagosome fusion with lysosomes, which should enhance M.abs killing. M.abs infection enhanced THP-1 ROS production as demonstrated by increased DHE, DCF fluorescence, and EPR signal. HO-1 inhibition further increased ROS production in infected macrophages. Our results indicate that HO-1 induction is important for M.abs growth during the early stages of infection, and that the HO-1 products bilirubin and biliverdin, perhaps through modulation of intracellular ROS levels, may be involved.

• Authors: Maher Y Abdalla, Iman M Ahmad, Barbara Switzer, Bradley E Britigan
• Journal: Redox biology (Redox Biol) Vol. 4 Pg. 328-39 ( 2015) ISSN: 2213-2317 [Electronic] Netherlands
• PMID: 25638774 (Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, U.S. Gov't, Non-P.H.S.)
• Copyright: Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.

Chemical References

• Metalloporphyrins
• NF-E2-Related Factor 2
• NFE2L2 protein, human
• Protein Kinase Inhibitors
• Protoporphyrins
• RNA, Small Interfering
• Reactive Oxygen Species
• tin protoporphyrin IX
• Heme Oxygenase-1
• p38 Mitogen-Activated Protein Kinases
• Tetradecanoylphorbol Acetate
• Biliverdine
• Bilirubin

Topics

• Bilirubin (pharmacology)
• Biliverdine (pharmacology)
• Cell Line, Tumor
• Enzyme Activation
• Gene Expression Regulation
• Heme Oxygenase-1 (genetics, metabolism)
• Host-Pathogen Interactions
• Humans
• Lysosomes (drug effects, metabolism)
• Macrophage Activation (drug effects)
• Macrophages (drug effects, enzymology, microbiology)
• Membrane Fusion (drug effects)
• Metalloporphyrins (pharmacology)
• Microbial Viability
• Mycobacterium (physiology)
• NF-E2-Related Factor 2 (antagonists & inhibitors, genetics, metabolism)
• Oxidative Stress
• Phagosomes (drug effects, metabolism)
• Protein Kinase Inhibitors (pharmacology)
• Protoporphyrins (pharmacology)
• RNA, Small Interfering (genetics, metabolism)
• Reactive Oxygen Species (metabolism)
• Signal Transduction
• Tetradecanoylphorbol Acetate (pharmacology)
• p38 Mitogen-Activated Protein Kinases (antagonists & inhibitors, genetics, metabolism)