Regulation of human beta-defensin-2 by Mycobacterium bovis bacillus Calmette-Guérin (BCG): involvement of PKC, JNK, and PI3K in human lung epithelial cell line (A549).
Human beta-defensin (HBD)-2 is an inducible antimicrobial peptide that plays an important role in innate immunity. Induction of this peptide by mycobacteria in epithelial cells has been reported. However, the mechanism(s) by which Mycobacterium bovis bacillus Calmette-Guérin (BCG) triggers gene transcription of HBD-2 remains poorly understood. In the present work we found that treatment of human epithelial cells with Ro32-0432 or Gö6976, two selective inhibitors of protein kinase C (PKC), significantly reduced the effect of M. bovis BCG on induced HBD-2 mRNA expression (65 and 80% inhibition by 10microM Ro32-0432, and 1microM Gö6976 as assessed by real-time PCR, respectively). Moreover, there was increased activation of c-Jun N-terminal kinase (JNK) and phosphatidylinositol-3-kinase (PI3K)/Akt in A549 cells infected with M. bovis BCG, and this JNK and PI3K activation was mediated through PKC. Finally, we found that M. bovis BCG-induced HBD-2 mRNA gene expression in A549 cells was dependent on JNK, and PI3K determined by real-time PCR analysis, which was attenuated by inhibitors of JNK (SP600125 and AG126), and PI3K (wortmannin and Ly294002). These studies are the first to show that M. bovis BCG-induced HBD-2 mRNA expression in A549 cells is regulated at least in part through activation of signaling proteins of PKC, JNK and PI3K.
Méndez-Samperio
Patricia
P
Departamento de Inmunología, Escuela Nacional de Ciencias Biológicas, D.F. 11340 México, Mexico. pmendezs@bios.encb.ipn.mx
Miranda
Elena
E
Trejo
Artemisa
A
D000890:Anti-Infective Agents / Q000378:metabolism*; D002460:Cell Line; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000378:metabolism; D004847:Epithelial Cells / Q000166:cytology / Q000378:metabolism*; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D006801:Humans; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism*; D009163:Mycobacterium bovis / Q000378:metabolism*; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D011493:Protein Kinase C / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology; D023083:beta-Defensins / Q000235:genetics / Q000378:metabolism*
D000890:Anti-Infective Agents; C106641:DEFB4A protein, human; D004791:Enzyme Inhibitors; D023083:beta-Defensins; D019869:Phosphatidylinositol 3-Kinases; D011493:Protein Kinase C; D048049:Extracellular Signal-Regulated MAP Kinases; D048031:JNK Mitogen-Activated Protein Kinases