A phosphoramidon-sensitive metalloprotease induces apoptosis of human endothelial cells by Group B Streptococcus.
We explored Group B Streptococcus (GBS)-induced apoptosis in human umbilical vein endothelial cells (HUVEC) and the role of phosphoramidon, a zinc metalloprotease inhibitor, in this process. GBS 90186 strain (serotype V, a blood isolate) and concentrated supernatant (CS) were used to investigate the viability and morphological alterations in HUVEC by Trypan blue uptake, electrophoresis in 2 % agarose gel and scanning electron microscopy assays. Apoptosis before and after phosphoramidon-treatment were verified by flow cytometry using annexin V-FITC labeling. Differences were considered significant when P < 0.05 using unpaired Student's t test. GBS and CS induced HUVEC death by apoptosis (76.5 and 32 %, respectively) with an increasing pro-apoptotic Bax expression and decreasing anti-apoptotic Bcl-2 expression. Caspase-3 was activated during GBS-induced endothelial apoptosis. Phosphoramidon reduced 89.3 and 100 % of GBS and CS cell death by apoptosis, respectively. Some GBS strains may induce cell death by apoptosis with involvement of metalloproteases and signaling through the intrinsic pathway of apoptosis, which may contribute to GBS survival during sepsis of adults and neonates.
Departamento de Biologia Celular, Instituto de Biologia Roberto Alcantara Gomes, Universidade do Estado do Rio de Janeiro, R. São Francisco Xavier, 524 - PHLC, 5° andar, sala 501B, Maracanã, Rio de Janeiro, CEP 20.550-013, Brazil.
Michelle Hanthequeste Bittencourt
MH
dos Santos
Andréia Ferreira Eduardo
AF
da Costa
Beatriz Jandre
BJ
Ferreira
Simone Lima
SL
Souza
Pamella
P
da Silva Lannes
Gabriela Silva
GS
Santos
Ana Luiza
AL
Mattos-Guaraldi
Prescilla Emy
PE
Nagao
D017304:Annexin A5 / Q000032:analysis; D017209:Apoptosis; D002470:Cell Survival; D002478:Cells, Cultured; D004586:Electrophoresis; D042783:Endothelial Cells / Q000382:microbiology* / Q000502:physiology*; D006020:Glycopeptides / Q000378:metabolism*; D006801:Humans; D045726:Metalloproteases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D008854:Microscopy, Electron; D011480:Protease Inhibitors / Q000378:metabolism*; D013194:Staining and Labeling / Q000379:methods; D013292:Streptococcus agalactiae / Q000201:enzymology*; D014343:Trypan Blue / Q000378:metabolism
D017304:Annexin A5; D006020:Glycopeptides; D011480:Protease Inhibitors; D045726:Metalloproteases; D014343:Trypan Blue; C008890:phosphoramidon