RNA interference in J774 macrophages reveals a role for coronin 1 in mycobacterial trafficking but not in actin-dependent processes.
Macrophages are crucial for innate immunity, apoptosis, and tissue remodeling, processes that rely on the capacity of macrophages to internalize and process cargo through phagocytosis. Coronin 1, a member of the WD repeat protein family of coronins specifically expressed in leukocytes, was originally identified as a molecule that is recruited to mycobacterial phagosomes and prevents the delivery of mycobacteria to lysosomes, allowing these to survive within phagosomes. However, a role for coronin 1 in mycobacterial pathogenesis has been disputed in favor for its role in mediating phagocytosis and cell motility. In this study, a role for coronin 1 in actin-mediated cellular processes was addressed using RNA interference in the murine macrophage cell line J774. It is shown that the absence of coronin 1 in J774 macrophages expressing small interfering RNA constructs specific for coronin 1 does not affect phagocytosis, macropinocytosis, cell locomotion, or regulation of NADPH oxidase activity. However, in coronin 1-negative J774 cells, internalized mycobacteria were rapidly transferred to lysosomes and killed. Therefore, these results show that in J774 cells coronin 1 has a specific role in modulating phagosome-lysosome transport upon mycobacterial infection and that it is dispensable for most F-actin-mediated cytoskeletal rearrangements.
Jayachandran
Rajesh
R
Biozentrum, University of Basel, 4056 Basel, Switzerland.
Gatfield
John
J
Massner
Jan
J
Albrecht
Imke
I
Zanolari
Bettina
B
Pieters
Jean
J
D000199:Actins / Q000378:metabolism*; D000818:Animals; D002460:Cell Line; D002633:Chemotaxis / Q000187:drug effects; D002999:Clone Cells; D004815:Epidermal Growth Factor / Q000494:pharmacology; D004912:Erythrocytes / Q000166:cytology / Q000187:drug effects; D005786:Gene Expression Regulation / Q000187:drug effects; D008262:Macrophage Activation / Q000187:drug effects; D008264:Macrophages / Q000166:cytology* / Q000187:drug effects / Q000201:enzymology / Q000382:microbiology*; D051379:Mice; D050296:Microbial Viability / Q000187:drug effects; D008840:Microfilament Proteins / Q000235:genetics / Q000378:metabolism*; D009161:Mycobacterium / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D019255:NADPH Oxidases / Q000378:metabolism; D010587:Phagocytosis / Q000187:drug effects; D010873:Pinocytosis / Q000187:drug effects; D021381:Protein Transport / Q000187:drug effects; D011554:Pseudopodia / Q000187:drug effects / Q000378:metabolism; D034622:RNA Interference / Q000187:drug effects; D034741:RNA, Small Interfering / Q000378:metabolism; D012756:Sheep
D000199:Actins; D008840:Microfilament Proteins; D034741:RNA, Small Interfering; C072061:coronin proteins; D004815:Epidermal Growth Factor; D019255:NADPH Oxidases