Coronavirus MHV-3-induced apoptosis in macrophages.
Infection with mouse hepatitis virus strain 3 (MHV-3) results in lethal fulminant hepatic necrosis in fully susceptible BALB/c mice compared to the minimal disease observed in resistant strain A/J mice. Macrophages play a central role in the pathogenesis of MHV-3-induced hepatitis. In the present study we have shown that MHV-3 infection of macrophages induces these cells to undergo apoptosis. Three methods to detect apoptosis were applied: flow cytometry analysis of nuclear DNA content, fluorescence microscopic visualization of apoptotic cells labeled by the TUNEL assay, and gel electrophoresis to detect DNA laddering. Apoptosis in A/J and BALB/c macrophages was first detected at 8 h postinfection (p.i.) and reached a maximum by 12 h p.i. The degree of MHV-3-induced apoptosis was much greater in A/J-derived macrophages than in BALB/c-derived cells. Apoptosis was inversely correlated with the development of typical MHV cytopathology, namely syncytia formation. Infected macrophages from A/J mice did not form synctia in contrast to the extensive synctia formation observed in BALB/c-derived macrophages. In MHV-3-infected BALB/c macrophage cultures, apoptotic cells were not incorporated into syncytia. Apoptosis was also inversely correlated with the expression of MHV-3-induced fgl2 prothrombinase in macrophages. These results add the murine coronavirus MHV-3 to the list of RNA-containing viruses capable of inducing apoptosis.
Belyavsky
M
M
Department of Pathology and Laboratory Medicine, Texas A&M University College of Medicine, 208 Reynolds Building, College Station, Texas, 77843-1114, USA.
Belyavskaya
E
E
Levy
G A
GA
Leibowitz
J L
JL
D000818:Animals; D017209:Apoptosis; D002478:Cells, Cultured; D004247:DNA / Q000032:analysis; D004587:Electrophoresis, Agar Gel; D005260:Female; D005340:Fibrinogen; D005434:Flow Cytometry; D015726:Giant Cells; D020287:In Situ Nick-End Labeling; D017737:Macrophages, Peritoneal / Q000166:cytology / Q000821:virology*; D051379:Mice; D008805:Mice, Inbred A; D008807:Mice, Inbred BALB C; D006517:Murine hepatitis virus / Q000502:physiology*; D012333:RNA, Messenger / Q000032:analysis; D013925:Thromboplastin / Q000235:genetics; D014779:Virus Replication
C490637:Fgl2 protein, mouse; D012333:RNA, Messenger; D005340:Fibrinogen; D004247:DNA; D013925:Thromboplastin