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Toll-like receptor 2 mediates ischemia-reperfusion injury of the small intestine in adult mice.

Watanabe T, Tanigawa T, Kobata A, Takeda S, Nadatani Y, Otani K, Yamagami H, Shiba M, Tominaga K, Fujiwara Y, Arakawa T - PLoS ONE (2014)

Bottom Line: Toll-like receptor 2 (TLR2) recognizes conserved molecular patterns associated with both gram-negative and gram-positive bacteria, and detects some endogenous ligands.TLR2 deficiency significantly inhibited the I/R-induced increase in MPO activity and the expression of mRNAs for TNF-α and ICAM-1, but did not affect the expression of COX-2 mRNA.TLR2 proteins were found to be expressed in the epithelial cells, inflammatory cells, and endothelial cells.

View Article: PubMed Central - PubMed

Affiliation: Department of Gastroenterology, Osaka City University Graduate School of Medicine, Osaka, Japan.

ABSTRACT
Toll-like receptor 2 (TLR2) recognizes conserved molecular patterns associated with both gram-negative and gram-positive bacteria, and detects some endogenous ligands. Previous studies demonstrated that in ischemia-reperfusion (I/R) injury of the small intestine, the TLR2-dependent signaling exerted preventive effects on the damage in young mice, but did not have a significant effect in neonatal mice. We investigated the role of TLR2 in adult ischemia-reperfusion injury in the small intestine. Wild-type and TLR2 knockout mice at 16 weeks of age were subjected to intestinal I/R injury. Some wild-type mice received anti-Ly-6G antibodies to deplete circulating neutrophils. In wild-type mice, I/R induced severe small intestinal injury characterized by infiltration by inflammatory cells, disruption of the mucosal epithelium, and mucosal bleeding. Compared to wild-type mice, TLR2 knockout mice exhibited less severe mucosal injury induced by I/R, with a 35%, 33%, and 43% reduction in histological grading score and luminal concentration of hemoglobin, and the numbers of apoptotic epithelial cells, respectively. The I/R increased the activity of myeloperoxidase (MPO), a marker of neutrophil infiltration, and the levels of mRNA expression of tumor necrosis factor-α (TNF-α), intercellular adhesion molecule-1 (ICAM-1), and cyclooxygenase-2 (COX-2) in the small intestine of the wild-type mice by 3.3-, 3.2-, and 13.0-fold, respectively. TLR2 deficiency significantly inhibited the I/R-induced increase in MPO activity and the expression of mRNAs for TNF-α and ICAM-1, but did not affect the expression of COX-2 mRNA. I/R also enhanced TLR2 mRNA expression by 2.9-fold. TLR2 proteins were found to be expressed in the epithelial cells, inflammatory cells, and endothelial cells. Neutrophil depletion prevented intestinal I/R injury in wild-type mice. These findings suggest that TLR2 may mediate I/R injury of the small intestine in adult mice via induction of inflammatory mediators such as TNF-α and ICAM-1.

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Roles of neutrophils in the intestinal ischemia-reperfusion injury.Wild-type mice that were intraperitoneally administered either rat anti-mouse Ly-6G antibodies or the vehicle (control rat IgG2a) 24 h before were subjected to 45 min of ischemia followed by 60 min of reperfusion. After removal of the small intestine, an assay of myeloperoxidase (MPO) activity (a marker of neutrophil infiltration, A), assessment of the intestinal injury by using the histological grading system (B), measuring the luminal hemoglobin concentration (C), and counting apoptotic epithelial cells with an antibody to ssDNA (D) were each performed. Each column represents the mean ± SD. N = 6–9. **P<0.01, * P<0.05 vs mice with sham operation, ##P<0.01, #P<0.05 vs mice that were subjected to the ischemia-reperfusion injury and given the vehicle. I/R; ischemia/reperfusion.
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pone-0110441-g003: Roles of neutrophils in the intestinal ischemia-reperfusion injury.Wild-type mice that were intraperitoneally administered either rat anti-mouse Ly-6G antibodies or the vehicle (control rat IgG2a) 24 h before were subjected to 45 min of ischemia followed by 60 min of reperfusion. After removal of the small intestine, an assay of myeloperoxidase (MPO) activity (a marker of neutrophil infiltration, A), assessment of the intestinal injury by using the histological grading system (B), measuring the luminal hemoglobin concentration (C), and counting apoptotic epithelial cells with an antibody to ssDNA (D) were each performed. Each column represents the mean ± SD. N = 6–9. **P<0.01, * P<0.05 vs mice with sham operation, ##P<0.01, #P<0.05 vs mice that were subjected to the ischemia-reperfusion injury and given the vehicle. I/R; ischemia/reperfusion.

Mentions: Neutrophil depletion by rat anti-mouse anti-Ly-6G antibodies inhibited the I/R-induced increase in MPO activity by 47% (Figure 3A), and resulted in prevention of the intestinal I/R injury. The histological grading score (Figure 3B), luminal concentration of hemoglobin (Figure 3C), and apoptotic indices (Figure 3D) in mice treated anti-Ly-6G antibodies were reduced by 53%, 64%, and 52%, respectively.


Toll-like receptor 2 mediates ischemia-reperfusion injury of the small intestine in adult mice.

Watanabe T, Tanigawa T, Kobata A, Takeda S, Nadatani Y, Otani K, Yamagami H, Shiba M, Tominaga K, Fujiwara Y, Arakawa T - PLoS ONE (2014)

Roles of neutrophils in the intestinal ischemia-reperfusion injury.Wild-type mice that were intraperitoneally administered either rat anti-mouse Ly-6G antibodies or the vehicle (control rat IgG2a) 24 h before were subjected to 45 min of ischemia followed by 60 min of reperfusion. After removal of the small intestine, an assay of myeloperoxidase (MPO) activity (a marker of neutrophil infiltration, A), assessment of the intestinal injury by using the histological grading system (B), measuring the luminal hemoglobin concentration (C), and counting apoptotic epithelial cells with an antibody to ssDNA (D) were each performed. Each column represents the mean ± SD. N = 6–9. **P<0.01, * P<0.05 vs mice with sham operation, ##P<0.01, #P<0.05 vs mice that were subjected to the ischemia-reperfusion injury and given the vehicle. I/R; ischemia/reperfusion.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4199713&req=5

pone-0110441-g003: Roles of neutrophils in the intestinal ischemia-reperfusion injury.Wild-type mice that were intraperitoneally administered either rat anti-mouse Ly-6G antibodies or the vehicle (control rat IgG2a) 24 h before were subjected to 45 min of ischemia followed by 60 min of reperfusion. After removal of the small intestine, an assay of myeloperoxidase (MPO) activity (a marker of neutrophil infiltration, A), assessment of the intestinal injury by using the histological grading system (B), measuring the luminal hemoglobin concentration (C), and counting apoptotic epithelial cells with an antibody to ssDNA (D) were each performed. Each column represents the mean ± SD. N = 6–9. **P<0.01, * P<0.05 vs mice with sham operation, ##P<0.01, #P<0.05 vs mice that were subjected to the ischemia-reperfusion injury and given the vehicle. I/R; ischemia/reperfusion.
Mentions: Neutrophil depletion by rat anti-mouse anti-Ly-6G antibodies inhibited the I/R-induced increase in MPO activity by 47% (Figure 3A), and resulted in prevention of the intestinal I/R injury. The histological grading score (Figure 3B), luminal concentration of hemoglobin (Figure 3C), and apoptotic indices (Figure 3D) in mice treated anti-Ly-6G antibodies were reduced by 53%, 64%, and 52%, respectively.

Bottom Line: Toll-like receptor 2 (TLR2) recognizes conserved molecular patterns associated with both gram-negative and gram-positive bacteria, and detects some endogenous ligands.TLR2 deficiency significantly inhibited the I/R-induced increase in MPO activity and the expression of mRNAs for TNF-α and ICAM-1, but did not affect the expression of COX-2 mRNA.TLR2 proteins were found to be expressed in the epithelial cells, inflammatory cells, and endothelial cells.

View Article: PubMed Central - PubMed

Affiliation: Department of Gastroenterology, Osaka City University Graduate School of Medicine, Osaka, Japan.

ABSTRACT
Toll-like receptor 2 (TLR2) recognizes conserved molecular patterns associated with both gram-negative and gram-positive bacteria, and detects some endogenous ligands. Previous studies demonstrated that in ischemia-reperfusion (I/R) injury of the small intestine, the TLR2-dependent signaling exerted preventive effects on the damage in young mice, but did not have a significant effect in neonatal mice. We investigated the role of TLR2 in adult ischemia-reperfusion injury in the small intestine. Wild-type and TLR2 knockout mice at 16 weeks of age were subjected to intestinal I/R injury. Some wild-type mice received anti-Ly-6G antibodies to deplete circulating neutrophils. In wild-type mice, I/R induced severe small intestinal injury characterized by infiltration by inflammatory cells, disruption of the mucosal epithelium, and mucosal bleeding. Compared to wild-type mice, TLR2 knockout mice exhibited less severe mucosal injury induced by I/R, with a 35%, 33%, and 43% reduction in histological grading score and luminal concentration of hemoglobin, and the numbers of apoptotic epithelial cells, respectively. The I/R increased the activity of myeloperoxidase (MPO), a marker of neutrophil infiltration, and the levels of mRNA expression of tumor necrosis factor-α (TNF-α), intercellular adhesion molecule-1 (ICAM-1), and cyclooxygenase-2 (COX-2) in the small intestine of the wild-type mice by 3.3-, 3.2-, and 13.0-fold, respectively. TLR2 deficiency significantly inhibited the I/R-induced increase in MPO activity and the expression of mRNAs for TNF-α and ICAM-1, but did not affect the expression of COX-2 mRNA. I/R also enhanced TLR2 mRNA expression by 2.9-fold. TLR2 proteins were found to be expressed in the epithelial cells, inflammatory cells, and endothelial cells. Neutrophil depletion prevented intestinal I/R injury in wild-type mice. These findings suggest that TLR2 may mediate I/R injury of the small intestine in adult mice via induction of inflammatory mediators such as TNF-α and ICAM-1.

Show MeSH
Related in: MedlinePlus