Immunohistochemical Detection of Toll-Like Receptor-2, -4 and -9 in Exocrine Glands Associated with Rat Alimentary Tract

Mantani

Masuda

et al. 2016

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The expressions of Toll-like receptor (TLR) -2, -4 and -9 were immunohistochemically investigated in the follicle-associated epithelium (FAE), and epithelia of the follicle-associated intestinal villus (FAIV) and ordinary intestinal villus (IV) in rat Peyer’s patch regions with no bacterial colonies on the mucous membranes. TLR-2 was expressed in the striated borders of microvillous columnar epithelial cells (MV) in both FAIV and IV except in the apices. However, TLR-2 expression in the striated borders was weaker in the epithelium of the follicular side of FAIV (f-FAIV) than in epithelia of IV and the anti-follicular side of FAIV. TLR-4 and -9 were not expressed in the FAIV and IV. In the FAE, TLR-2, -4 and -9 were not expressed in the striated borders of MV, but the roofs of some typical M-cells were immunopositive for all TLRs. Especially, no TLR-positive MV were found at the FAE sites where M-cells appeared most frequently. In the follicle-associated intestinal crypt (FAIC), immunopositivity for all TLRs was observed in the striated borders of MV and the luminal substances. In conclusion, the lower levels of TLR-2 in both FAE and the epithelium of f-FAIV probably reduce recognition of indigenous bacteria. TLR-2, -4 and -9 appear not to participate directly in differentiation of MV into M-cells, because TLRs were not expressed in any MV in the upstream region of M-cells in FAE with no settlement of indigenous bacteria in the rat Peyer’s patches.

Section: Discussionsupporting

confidence: 51%

Differential expression of Toll-like receptor-2, -4 and -9 in follicle-associated epithelium from epithelia of both follicle-associated intestinal villi and ordinary intestinal villi in rat Peyer’s patches

Mantani

Masuda

et al. 2016

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“…Intestinal IgA have been shown to bind lipopolysaccharide from indigenous bacteria [23]. Considering that Gram-negative bacteria are more abundant in deep portions of intervillous spaces of the rat small intestine than Gram-positive bacteria [24], an increase of IgA + cells—probably plasma cells—in the apical portion of the intestinal villus in response to the expansion of bacterial colonies into the intervillous spaces might contribute to the protection against or neutralization of absorbed bacterial constituents such as lipopolysaccharide from Gram-negative bacteria.…”

Section: Discussionmentioning

confidence: 99%

Effects of the expansion of bacterial colonies into the intervillous spaces on the localization of several lymphocyte lineages in the rat ileum

Mantani

Miyamoto

et al. 2019

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The effect of bacterial colonies expanded into the intervillous spaces on the localization of several lymphocyte lineages was immunohistochemically investigated in two types of mucosa: ordinary mucosa of rat ileum, which consists of mucosa without any mucosal lymphatic tissue; and follicle-associated mucosa (FAM), which accompanies the parafollicular area under the muscularis mucosae in the rat ileal Peyer’s patch. The results showed that bacterial colonies in the intervillous spaces induced increased populations of CD8 + cells in the epithelium of the intestinal villus in ordinary mucosa (IV) and intestinal villus in FAM (IV-FAM). Bacterial colonies in the intervillous spaces were also associated with increased numbers of IgA + cells, which were mainly localized in the lamina propria of basal portions of IV and IV-FAM, and with expanded localization of IgA + cells into the villous apex in both IV and IV-FAM. Moreover, IgA + cells around the intestinal crypts adjacent to IV or IV-FAM were also increased in response to bacterial colonies. In the IV-FAM, but not IV, L-selectin + cells, which were found to be immunopositive for TCRαβ or CD19, were drastically increased in the lamina propria from the crypt to middle portion of IV-FAM and in the lumen of central lymph vessel of IV-FAM in response to the bacterial colonies in the intervillous spaces. These findings revealed that the expansion of bacterial colonies into the intervillous spaces accompanies the change of histological localization of the lymphocyte lineage in both the ordinary mucosa and FAM.

“…Gram-negative bacteria possess lipopolysaccharides (LPS) [ 4 ], which are recognized and bound by Toll-like receptor-4 (TLR-4) [ 7 ]. The secretory form of TLR-4 (sTLR-4) is secreted from the intestinal crypts and other exocrine glands in the rat alimentary tract [ 25 ]. The sTLR-4 immunopositive minute vesicles, possibly sTLR-4-LPS complexes, exist in the villous columnar epithelial cells of villous apices in the rat duodenum [ 24 ].…”

Section: Discussionmentioning

confidence: 99%

“…The sTLR-4 immunopositive minute vesicles, possibly sTLR-4-LPS complexes, exist in the villous columnar epithelial cells of villous apices in the rat duodenum [ 24 ]. In the rat liver, the sTLR-4 immunopositive minute vesicles also exist in the perisinusoidal spaces and hepatocytes [ 25 ]. It is well known that LPS are present in the portal vein blood of various human patients, but no LPS are detected in the systemic circulation except in cases of liver disease [ 20 , 39 ].…”

Section: Discussionmentioning

confidence: 99%

Immunohistochemical and histoplanimetrical study on the endothelial receptor involved in transportation of minute chylomicrons into subepithelial portal blood in intestinal villi of the rat jejunum

Takahara

Nishida

et al. 2015

Self Cite

A portion of the minute chylomicrons less than 75 nm in diameter are transcytosed from the extravascular tissue into the subepithelial blood capillaries (sBC) in the villous apices of the rat jejunum. However, the details of the transportation mechanism have not been clarified. In this study, the endothelial receptor involved in the transportation of minute chylomicrons into the sBC’s lumina was immunohistochemically and histoplanimetrically examined in intestinal villi of the rat jejunum. Immunopositivity for very low density lipoprotein (VLDL) receptor was detected on the luminal and basal surfaces of the endothelial cells of sBC in approximately 68% of those apices of jejunal villi that possessed numerous chylomicrons in the lamina propria, while VLDL receptor was detected on the endothelial cells of sBC in only approximately 8% of intestinal villi that possessed few or no chylomicrons in the lamina propria. No immunopositivity for LDL receptor was detected in the sBC of all intestinal villi. These findings suggest that VLDL receptor is expressed by the endothelial cells of the sBC in conjunction with the filling of the lamina propria of jejunal villi with many chylomicrons produced by the villous columnar epithelial cells and that the VLDL receptor mediates the transportation of minute chylomicrons, maybe VLDL, into the subepithelial portal blood from the extravascular tissue of the rat jejunal villi.