The alpha C protein mediates internalization of group B<i>Streptococcus</i>within human cervical epithelial cells

Bolduc, Gilles R.; Baron, Miriam J.; Gravekamp, Claudia; Lachenauer, Catherine S.; Madoff, Lawrence C.

doi:10.1046/j.1462-5822.2002.00227.x

Cited by 74 publications

(71 citation statements)

References 27 publications

(35 reference statements)

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“…Sample Preparation-The native and mutant recombinant NtACP were expressed in E. coli BL21(DE3) (Novagen) with a His 6 tag fused at their C-terminal end and purified as previously described (15). Selenomethionyl (SeMet) proteins were expressed overnight in E. coli BL21(DE3) at 25°C following a protocol previously described for the use of non-auxotrophic cells (25).…”

Section: Methodsmentioning

confidence: 99%

“…ACP consists of an Nterminal domain (174 amino acids), a variable number of tandem repeats of 82 amino acids each, and a 45-amino acid C-terminal domain containing a LPXTG peptidoglycan-binding motif. NtACP mediates GBS internalization within human epithelial cells (15). NtACP in association with a repeat domain is necessary to bind GAG (20).…”

mentioning

confidence: 99%

“…Four to six percent of all neonatal GBS infections result in death (6,9). In vitro, GBS adheres to (10,11), internalizes within (12)(13)(14), and translocates across (15) intact human epithelial and endothelial cells. Little is known about the bacterial components that allow this pathogen to adhere to and penetrate cellular membranes.…”

mentioning

confidence: 99%

“…Previous studies suggest that surface proteins are significantly involved in the process (11,16). The surface-expressed GBS alpha C protein (ACP) has been shown to act as an invasin (15). ACP is the prototype of a family of surface-expressed proteins containing long tandem repeats (alpha-like proteins (Alp)).…”

mentioning

confidence: 99%

“…Deletion of the ACP gene bca attenuates the virulence of GBS 5-7-fold and the internalization of GBS into cervical epithelial cells by 80% (19). Furthermore, the amount of internalized GBS within human cervical epithelial cells in vitro is inhibited by 75% in the presence of the N-terminal domain of ACP (NtACP) (15), suggesting that ACP is a major determinant of virulence. Recently, ACP has been reported to bind glycosaminoglycans (GAG) (20).…”

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confidence: 99%

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Crystal Structure of the N-terminal Domain of the Group B Streptococcus Alpha C Protein

Auperin

Bolduc

Baron

et al. 2005

Journal of Biological Chemistry

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Group B Streptococcus (GBS) is the leading cause of bacterial pneumonia, sepsis, and meningitis among neonates and an important cause of morbidity among pregnant women and immunocompromised adults. Invasive diseases due to GBS are attributed to the ability of the pathogen to translocate across human epithelial surfaces. The alpha C protein (ACP) has been identified as an invasin that plays a role in internalization and translocation of GBS across epithelial cells. The soluble N-terminal domain of ACP (NtACP) blocks the internalization of GBS. We determined the 1.86-Å resolution crystal structure of NtACP comprising residues Ser 52 through Leu 225 of the full-length ACP. NtACP has two domains, an N-terminal ␤-sandwich and a C-terminal three-helix bundle. Structural and topological alignments reveal that the ␤-sandwich shares structural elements with the type III fibronectin fold (FnIII), but includes structural elaborations that make it unique. We have identified a potential integrin-binding motif consisting of Lys-Thr-Asp 146 , Arg 110 , and Asp 118 . A similar arrangement of charged residues has been described in other invasins. ACP shows a heparin binding activity that requires NtACP. We propose a possible heparin-binding site, including one surface of the three-helix bundle, and nearby portions of the sandwich and repeat domains. We have validated this prediction using assays of the heparin binding and cell-adhesion properties of engineered fragments of ACP. This is the first crystal structure of a member of the highly conserved Gram-positive surface alpha-like protein family, and it will enable the internalization mechanism of GBS to be dissected at the atomic level.Group B Streptococcus (GBS) 1 (Streptococcus agalactiae) remains the leading cause of invasive bacterial diseases in neonates, despite its decline in prevalence during the last decade because of intrapartum chemoprophylatic therapy (1, 2). It is also an important cause of morbidity in pregnant women and non-pregnant adults with underlying medical conditions (3-5). GBS colonizes the human gastrointestinal and genitourinary tracts and may cause chorioamnionitis and urinary tract infection in pregnant women and a range of invasive infections in elderly and immunocompromised adults (1, 6 -8). During labor and delivery, GBS may be transmitted to neonates, causing pneumonia, sepsis, or meningitis. Four to six percent of all neonatal GBS infections result in death (6, 9). In vitro, GBS adheres to (10, 11), internalizes within (12-14), and translocates across (15) intact human epithelial and endothelial cells. Little is known about the bacterial components that allow this pathogen to adhere to and penetrate cellular membranes. Previous studies suggest that surface proteins are significantly involved in the process (11, 16). The surface-expressed GBS alpha C protein (ACP) has been shown to act as an invasin (15). ACP is the prototype of a family of surface-expressed proteins containing long tandem repeats (alpha-like proteins (Alp)). Members of this famil...

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Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Crystal Structure of the N-terminal Domain of the Group B Streptococcus Alpha C Protein

Auperin

Bolduc

Baron

et al. 2005

Journal of Biological Chemistry

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Oxidative Stress, Cytokine/Chemokine and Disruption of Blood–Brain Barrier in Neonate Rats After Meningitis by Streptococcus agalactiae

et al. 2011

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We verify the levels of cytokine/chemokine, myeloperoxidase activity, oxidative stress and disruption of BBB in hippocampus and cortex of the neonate Wistar rats after meningitis by S. agalactiae. In the hippocampus the levels were increased of CINC-1 at 6 h and 12 h, IL-1β at 6, 12 and 24 h, IL-6 at 6, 24 and 96 h, IL-10 at 24, 48 and 96 h and TNF-α at 24 h and 96 h. In the cortex the CINC-1 and IL-1β levels were found increased at 6 h. The MPO activity was significantly elevated at 24, 48 and 98 h in hippocampus and at 6, 12, 24, 48 and 96 h in the cortex. The breakdown of BBB started at 12 h.TBARS levels were elevated in the hippocampus at 6, 12, 24, 48, 72 and 96 h and cortex at 72 and 96 h. Protein carbonyls were elevated in the hippocampus and cortex at 6, 24, 48, 72 and 96 h. There was a decrease of SOD activity in hippocampus and in cortex. Catalase activity was elevated in hippocampus at 6 h and in the cortex at 12 and 96 h. Neonatal bacterial infections of the CNS are severe, the interference with the complex network of cytokines/chemokine, other inflammatory mediators and oxidants tend to aggravate the illness and can be involved in the breakdown of the BBB.

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A cytosol derived factor of Group B streptococcus prevent its invasion into human epithelial cells

Pai

Parashar

Pai

et al. 2018

World J Microbiol Biotechnol

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Group B streptococcus (GBS) or Streptococcus agalactiae, is an opportunistic pathogen causing a wide range of infections like pneumonia, sepsis, and meningitis in newborn, pregnant women and adults. While this bacterium has adapted well to asymptomatic colonization of adult humans, it still remains a potentially devastating pathogen to susceptible infants. Advances in molecular techniques and refinement of in vitro and in vivo model systems have elucidated key elements of the pathogenic process, from initial attachment to the maternal vaginal epithelium to penetration of the newborn blood-brain barrier. Still, the formidable array of GBS virulence factors makes this bacterium at the forefront of neonatal pathogens. The involvement of bacterial components in the host-pathogen interaction of GBS pathogenesis and its related diseases is not clearly understood. In this study we demonstrated the role of a 39 kDa factor from GBS which plays an important role in the process of its invasion. We found a homogeneous 39 kDa factor from the cytosol of GBS after following a combination of sequential purification steps involving molecular sieving and ion exchange chromatography using ACTA-FPLC system. Its N-terminal sequence showed a homology with xenobiotic response element type transcriptional regulator protein, a 40 kDa protein of Streptococcus. This factor leads to inhibition of GBS invasion in HeLa and A549 cells. This protein also showed sensitivity and specific cross reactivity with the antibodies raised against it in New Zealand white rabbits by western immunoblotting. This inhibitory factor was further confirmed tolerant for its cytotoxicity. These results add a novel aspect to bacterial pathogenesis where bacteria's own intracellular protein component can act as a potential therapeutic candidate by decreasing the severity of disease thus promoting its invasion inhibition.

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The alpha C protein mediates internalization of group BStreptococcuswithin human cervical epithelial cells

Cited by 74 publications

References 27 publications

Crystal Structure of the N-terminal Domain of the Group B Streptococcus Alpha C Protein

Crystal Structure of the N-terminal Domain of the Group B Streptococcus Alpha C Protein

Oxidative Stress, Cytokine/Chemokine and Disruption of Blood–Brain Barrier in Neonate Rats After Meningitis by Streptococcus agalactiae

A cytosol derived factor of Group B streptococcus prevent its invasion into human epithelial cells

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