Abstract
Lipopolysaccharide (LPS) and lipoteichoic acid (LTA), principal cell wall components of Gram-negative and Gram-positive bacteria, respectively, play a central role in altering the blood-brain barrier and facilitate bacterial infection of the host brain. Despite the significance of bacterial toxins in disease pathogenesis, mechanisms by which toxins impair the barrier are not yet known. This study, using an in vitro cell culture model, showed that LPS and LTA interacted with the endothelial cells and disrupted the tight junction between the cells that increased the barrier's permeability. Both toxins increased inducible nitric oxide synthase (iNOS) mRNA that is indicative of an increase in intracellular NO release, disrupted architecture of the tight junction proteins, suppressed zonula occludens-1 (ZO-1) and occludin (OCL) and junctional adhesive molecules (JAM) mRNA levels, and increased tumor necrosis factor alpha (TNFα) and interleukin-1 beta (IL-1β) mRNA levels. Anti-CD14 antibodies blocked the increase in TNFα and IL-1β mRNA levels but did not affect either changes in the tight junction or iNOS, ZO-1, OCL, and JAM mRNA levels in endothelial cells and astrocytes. Although both toxins did not cross the endothelial barrier, the abluminal neurons exhibited high inflammatory activity characterized by a sequential increase in TNFα, IL-1β, external receptor kinase (ERK), and RelA-p50 that induced inflammation, followed by an increase in anti-inflammatory/apoptotic factors including IL-10 and cysteine-aspartic acid protease-8 (CASPASE-8), which resolve inflammation and induce apoptosis. Anti-CD14 antibodies in luminal buffer blocked the pro- and anti-inflammatory effects of the toxins in neurons. Thus, the CD14-TLR cascade that participates in the inflammatory effects of toxins may not participate in the toxin-induced barrier disruption in vitro. Since the toxins did not cross the endothelial barrier, induction of inflammation in neurons was due to a release of proinflammatory cytokines in the abluminal fluid.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 331-347 |
| Number of pages | 17 |
| Journal | Toxicology Mechanisms and Methods |
| Volume | 17 |
| Issue number | 6 |
| DOIs | |
| State | Published - Jul 1 2007 |
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Keywords
- Apoptosis
- Blood-Brain Barrier
- Endothelial Tight Junction
- Lipopolysaccharide
- Lipoteichoic Acid
- NFκB
Cite this
Effects of bacterial toxins on endothelial tight junction in vitro : A mechanism-based investigation. / Singh, Ashok K; Jiang, Yin; Gupta, Shveta.
In: Toxicology Mechanisms and Methods, Vol. 17, No. 6, 01.07.2007, p. 331-347.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Effects of bacterial toxins on endothelial tight junction in vitro
T2 - A mechanism-based investigation
AU - Singh, Ashok K
AU - Jiang, Yin
AU - Gupta, Shveta
PY - 2007/7/1
Y1 - 2007/7/1
N2 - Lipopolysaccharide (LPS) and lipoteichoic acid (LTA), principal cell wall components of Gram-negative and Gram-positive bacteria, respectively, play a central role in altering the blood-brain barrier and facilitate bacterial infection of the host brain. Despite the significance of bacterial toxins in disease pathogenesis, mechanisms by which toxins impair the barrier are not yet known. This study, using an in vitro cell culture model, showed that LPS and LTA interacted with the endothelial cells and disrupted the tight junction between the cells that increased the barrier's permeability. Both toxins increased inducible nitric oxide synthase (iNOS) mRNA that is indicative of an increase in intracellular NO release, disrupted architecture of the tight junction proteins, suppressed zonula occludens-1 (ZO-1) and occludin (OCL) and junctional adhesive molecules (JAM) mRNA levels, and increased tumor necrosis factor alpha (TNFα) and interleukin-1 beta (IL-1β) mRNA levels. Anti-CD14 antibodies blocked the increase in TNFα and IL-1β mRNA levels but did not affect either changes in the tight junction or iNOS, ZO-1, OCL, and JAM mRNA levels in endothelial cells and astrocytes. Although both toxins did not cross the endothelial barrier, the abluminal neurons exhibited high inflammatory activity characterized by a sequential increase in TNFα, IL-1β, external receptor kinase (ERK), and RelA-p50 that induced inflammation, followed by an increase in anti-inflammatory/apoptotic factors including IL-10 and cysteine-aspartic acid protease-8 (CASPASE-8), which resolve inflammation and induce apoptosis. Anti-CD14 antibodies in luminal buffer blocked the pro- and anti-inflammatory effects of the toxins in neurons. Thus, the CD14-TLR cascade that participates in the inflammatory effects of toxins may not participate in the toxin-induced barrier disruption in vitro. Since the toxins did not cross the endothelial barrier, induction of inflammation in neurons was due to a release of proinflammatory cytokines in the abluminal fluid.
AB - Lipopolysaccharide (LPS) and lipoteichoic acid (LTA), principal cell wall components of Gram-negative and Gram-positive bacteria, respectively, play a central role in altering the blood-brain barrier and facilitate bacterial infection of the host brain. Despite the significance of bacterial toxins in disease pathogenesis, mechanisms by which toxins impair the barrier are not yet known. This study, using an in vitro cell culture model, showed that LPS and LTA interacted with the endothelial cells and disrupted the tight junction between the cells that increased the barrier's permeability. Both toxins increased inducible nitric oxide synthase (iNOS) mRNA that is indicative of an increase in intracellular NO release, disrupted architecture of the tight junction proteins, suppressed zonula occludens-1 (ZO-1) and occludin (OCL) and junctional adhesive molecules (JAM) mRNA levels, and increased tumor necrosis factor alpha (TNFα) and interleukin-1 beta (IL-1β) mRNA levels. Anti-CD14 antibodies blocked the increase in TNFα and IL-1β mRNA levels but did not affect either changes in the tight junction or iNOS, ZO-1, OCL, and JAM mRNA levels in endothelial cells and astrocytes. Although both toxins did not cross the endothelial barrier, the abluminal neurons exhibited high inflammatory activity characterized by a sequential increase in TNFα, IL-1β, external receptor kinase (ERK), and RelA-p50 that induced inflammation, followed by an increase in anti-inflammatory/apoptotic factors including IL-10 and cysteine-aspartic acid protease-8 (CASPASE-8), which resolve inflammation and induce apoptosis. Anti-CD14 antibodies in luminal buffer blocked the pro- and anti-inflammatory effects of the toxins in neurons. Thus, the CD14-TLR cascade that participates in the inflammatory effects of toxins may not participate in the toxin-induced barrier disruption in vitro. Since the toxins did not cross the endothelial barrier, induction of inflammation in neurons was due to a release of proinflammatory cytokines in the abluminal fluid.
KW - Apoptosis
KW - Blood-Brain Barrier
KW - Endothelial Tight Junction
KW - Lipopolysaccharide
KW - Lipoteichoic Acid
KW - NFκB
UR - http://www.scopus.com/inward/record.url?scp=34547155721&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=34547155721&partnerID=8YFLogxK
U2 - 10.1080/15376510601077029
DO - 10.1080/15376510601077029
M3 - Article
VL - 17
SP - 331
EP - 347
JO - Toxicology Mechanisms and Methods
JF - Toxicology Mechanisms and Methods
SN - 1537-6516
IS - 6
ER -