Limits...
Tumor necrosis factor-dependent segmental control of MIG expression by high endothelial venules in inflamed lymph nodes regulates monocyte recruitment.

Janatpour MJ, Hudak S, Sathe M, Sedgwick JD, McEvoy LM - J. Exp. Med. (2001)

Bottom Line: Quantitative PCR analyses revealed the upregulation of many chemokines in the inflamed lymph node, including MCP-1 and MIG.HEVs did not express detectable levels of MCP-1; however, a subset of HEVs in inflamed lymph nodes in wild-type (but not tumor necrosis factor [TNF] mice) expressed MIG and this subset of HEVs preferentially supported monocyte binding.Together, these results suggest that the lymph node microenvironment can dictate the nature of molecules expressed on HEV subsets in a TNF-dependent fashion and that inflammation-induced MIG expression by HEVs can mediate monocyte recruitment.

View Article: PubMed Central - PubMed

Affiliation: DNAX Research Institute, Inc., Palo Alto, CA 94304, USA.

ABSTRACT
Monocytes recruited from the blood are key contributors to the nature of an immune response. While monocyte recruitment in a subset of immunopathologies has been well studied and largely attributed to the chemokine monocyte chemoattractant protein (MCP)-1, mechanisms mediating such recruitment to other sites of inflammation remain elusive. Here, we showed that localized inflammation resulted in an increased binding of monocytes to perifollicular high endothelial venules (HEVs) of lymph nodes draining a local inflammatory site. Quantitative PCR analyses revealed the upregulation of many chemokines in the inflamed lymph node, including MCP-1 and MIG. HEVs did not express detectable levels of MCP-1; however, a subset of HEVs in inflamed lymph nodes in wild-type (but not tumor necrosis factor [TNF] mice) expressed MIG and this subset of HEVs preferentially supported monocyte binding. Expression of CXCR3, the receptor for MIG, was detected on a small subset of peripheral blood monocytes and on a significant percentage of recruited monocytes. Most importantly, in both ex vivo and in vivo assays, neutralizing anti-MIG antibodies blocked monocyte binding to inflamed lymph node HEVs. Together, these results suggest that the lymph node microenvironment can dictate the nature of molecules expressed on HEV subsets in a TNF-dependent fashion and that inflammation-induced MIG expression by HEVs can mediate monocyte recruitment.

Show MeSH

Related in: MedlinePlus

Recruitment of monocytes to lymph node HEVs is increased in wild-type mice, but not in TNF  mice, upon inflammation. 3 d after inducing inflammation, lymph nodes draining either inflamed footpads (black bars) or footpads that were not inflamed (white bars) were embedded in O.C.T., sectioned and subjected to the snapshot assay. Double-indirect immunohistochemistry was performed to identify all HEVs (red; see inset) and monocytes (green). The data is presented as percentage of total HEVs with at least one bound monocyte. Inducing inflammation in the footpads of wild-type mice results in nearly a threefold increase in monocyte recruitment to lymph node HEVs. TNF  mice have a reduced ability to recruit monocytes to HEVs upon inflammation, compared to wild-type mice. This experiment was repeated four times for wild-type mice and three times for TNF  mice. P value < 0.05.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC2195975&req=5

fig2: Recruitment of monocytes to lymph node HEVs is increased in wild-type mice, but not in TNF mice, upon inflammation. 3 d after inducing inflammation, lymph nodes draining either inflamed footpads (black bars) or footpads that were not inflamed (white bars) were embedded in O.C.T., sectioned and subjected to the snapshot assay. Double-indirect immunohistochemistry was performed to identify all HEVs (red; see inset) and monocytes (green). The data is presented as percentage of total HEVs with at least one bound monocyte. Inducing inflammation in the footpads of wild-type mice results in nearly a threefold increase in monocyte recruitment to lymph node HEVs. TNF mice have a reduced ability to recruit monocytes to HEVs upon inflammation, compared to wild-type mice. This experiment was repeated four times for wild-type mice and three times for TNF mice. P value < 0.05.

Mentions: We quantitated the increased monocyte recruitment across lymph node HEVs upon inflammation using an in vivo “snapshot” assay (Fig. 2) . 3 d after inducing inflammation, lymph nodes draining either inflamed footpads or footpads that were not inflamed were embedded in O.C.T. and sectioned. Double-indirect immunohistochemistry was performed to identify HEVs (PNAd+, red; Fig. 2 inset) and monocytes (CD11b-bright, green). These CD11b-bright cells are positive for CD68 and negative for CD3, CD19, and NK1.1 (data not shown). HEVs were counted and scored for the presence or absence of bound monocytes at the time of sacrifice and percentage of total HEVs with one or more monocytes bound was calculated.


Tumor necrosis factor-dependent segmental control of MIG expression by high endothelial venules in inflamed lymph nodes regulates monocyte recruitment.

Janatpour MJ, Hudak S, Sathe M, Sedgwick JD, McEvoy LM - J. Exp. Med. (2001)

Recruitment of monocytes to lymph node HEVs is increased in wild-type mice, but not in TNF  mice, upon inflammation. 3 d after inducing inflammation, lymph nodes draining either inflamed footpads (black bars) or footpads that were not inflamed (white bars) were embedded in O.C.T., sectioned and subjected to the snapshot assay. Double-indirect immunohistochemistry was performed to identify all HEVs (red; see inset) and monocytes (green). The data is presented as percentage of total HEVs with at least one bound monocyte. Inducing inflammation in the footpads of wild-type mice results in nearly a threefold increase in monocyte recruitment to lymph node HEVs. TNF  mice have a reduced ability to recruit monocytes to HEVs upon inflammation, compared to wild-type mice. This experiment was repeated four times for wild-type mice and three times for TNF  mice. P value < 0.05.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2195975&req=5

fig2: Recruitment of monocytes to lymph node HEVs is increased in wild-type mice, but not in TNF mice, upon inflammation. 3 d after inducing inflammation, lymph nodes draining either inflamed footpads (black bars) or footpads that were not inflamed (white bars) were embedded in O.C.T., sectioned and subjected to the snapshot assay. Double-indirect immunohistochemistry was performed to identify all HEVs (red; see inset) and monocytes (green). The data is presented as percentage of total HEVs with at least one bound monocyte. Inducing inflammation in the footpads of wild-type mice results in nearly a threefold increase in monocyte recruitment to lymph node HEVs. TNF mice have a reduced ability to recruit monocytes to HEVs upon inflammation, compared to wild-type mice. This experiment was repeated four times for wild-type mice and three times for TNF mice. P value < 0.05.
Mentions: We quantitated the increased monocyte recruitment across lymph node HEVs upon inflammation using an in vivo “snapshot” assay (Fig. 2) . 3 d after inducing inflammation, lymph nodes draining either inflamed footpads or footpads that were not inflamed were embedded in O.C.T. and sectioned. Double-indirect immunohistochemistry was performed to identify HEVs (PNAd+, red; Fig. 2 inset) and monocytes (CD11b-bright, green). These CD11b-bright cells are positive for CD68 and negative for CD3, CD19, and NK1.1 (data not shown). HEVs were counted and scored for the presence or absence of bound monocytes at the time of sacrifice and percentage of total HEVs with one or more monocytes bound was calculated.

Bottom Line: Quantitative PCR analyses revealed the upregulation of many chemokines in the inflamed lymph node, including MCP-1 and MIG.HEVs did not express detectable levels of MCP-1; however, a subset of HEVs in inflamed lymph nodes in wild-type (but not tumor necrosis factor [TNF] mice) expressed MIG and this subset of HEVs preferentially supported monocyte binding.Together, these results suggest that the lymph node microenvironment can dictate the nature of molecules expressed on HEV subsets in a TNF-dependent fashion and that inflammation-induced MIG expression by HEVs can mediate monocyte recruitment.

View Article: PubMed Central - PubMed

Affiliation: DNAX Research Institute, Inc., Palo Alto, CA 94304, USA.

ABSTRACT
Monocytes recruited from the blood are key contributors to the nature of an immune response. While monocyte recruitment in a subset of immunopathologies has been well studied and largely attributed to the chemokine monocyte chemoattractant protein (MCP)-1, mechanisms mediating such recruitment to other sites of inflammation remain elusive. Here, we showed that localized inflammation resulted in an increased binding of monocytes to perifollicular high endothelial venules (HEVs) of lymph nodes draining a local inflammatory site. Quantitative PCR analyses revealed the upregulation of many chemokines in the inflamed lymph node, including MCP-1 and MIG. HEVs did not express detectable levels of MCP-1; however, a subset of HEVs in inflamed lymph nodes in wild-type (but not tumor necrosis factor [TNF] mice) expressed MIG and this subset of HEVs preferentially supported monocyte binding. Expression of CXCR3, the receptor for MIG, was detected on a small subset of peripheral blood monocytes and on a significant percentage of recruited monocytes. Most importantly, in both ex vivo and in vivo assays, neutralizing anti-MIG antibodies blocked monocyte binding to inflamed lymph node HEVs. Together, these results suggest that the lymph node microenvironment can dictate the nature of molecules expressed on HEV subsets in a TNF-dependent fashion and that inflammation-induced MIG expression by HEVs can mediate monocyte recruitment.

Show MeSH
Related in: MedlinePlus