Critical involvement of the ATM-dependent DNA damage response in the apoptotic demise of HIV-1-elicited syncytia.
DNA damage can activate the oncosuppressor protein ataxia telangiectasia mutated (ATM), which phosphorylates the histone H2AX within characteristic DNA damage foci. Here, we show that ATM undergoes an activating phosphorylation in syncytia elicited by the envelope glycoprotein complex (Env) of human immunodeficiency virus-1 (HIV-1) in vitro. This was accompanied by aggregation of ATM in discrete nuclear foci that also contained phospho-histone H2AX. DNA damage foci containing phosphorylated ATM and H2AX were detectable in syncytia present in the brain or lymph nodes from patients with HIV-1 infection, as well as in a fraction of blood leukocytes, correlating with viral status. Knockdown of ATM or of its obligate activating factor NBS1 (Nijmegen breakage syndrome 1 protein), as well as pharmacological inhibition of ATM with KU-55933, inhibited H2AX phosphorylation and prevented Env-elicited syncytia from undergoing apoptosis. ATM was found indispensable for the activation of MAP kinase p38, which catalyzes the activating phosphorylation of p53 on serine 46, thereby causing p53 dependent apoptosis. Both wild type HIV-1 and an HIV-1 mutant lacking integrase activity induced syncytial apoptosis, which could be suppressed by inhibiting ATM. HIV-1-infected T lymphoblasts from patients with inactivating ATM or NBS1 mutations also exhibited reduced syncytial apoptosis. Altogether these results indicate that apoptosis induced by a fusogenic HIV-1 Env follows a pro-apoptotic pathway involving the sequential activation of ATM, p38MAPK and p53.
Perfettini
Jean-Luc
JL
INSERM U848, Institut Gustave Roussy, Villejuif, France.
Nardacci
Roberta
R
Bourouba
Mehdi
M
Subra
Frédéric
F
Gros
Laurent
L
Séror
Claire
C
Manic
Gwenola
G
Rosselli
Filippo
F
Amendola
Alessandra
A
Masdehors
Peggy
P
Chessa
Luciana
L
Novelli
Giuseppe
G
Ojcius
David M
DM
Siwicki
Jan Konrad
JK
Chechlinska
Magdalena
M
Auclair
Christian
C
Regueiro
José R
JR
de Thé
Hugues
H
Gougeon
Marie-Lise
ML
Piacentini
Mauro
M
Kroemer
Guido
G
D000328:Adult; D017209:Apoptosis / Q000502:physiology*; D064007:Ataxia Telangiectasia Mutated Proteins; D018797:Cell Cycle Proteins / Q000502:physiology*; D004249:DNA Damage; D004268:DNA-Binding Proteins / Q000502:physiology*; D005260:Female; D015726:Giant Cells / Q000821:virology*; D015497:HIV-1 / Q000502:physiology*; D006367:HeLa Cells; D006657:Histones / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000502:physiology*; D034622:RNA Interference; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism; D025521:Tumor Suppressor Proteins / Q000502:physiology*; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; D006657:Histones; D016159:Tumor Suppressor Protein p53; D025521:Tumor Suppressor Proteins; C576324:ATM protein, human; D064007:Ataxia Telangiectasia Mutated Proteins; D017346:Protein Serine-Threonine Kinases; D048051:p38 Mitogen-Activated Protein Kinases