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Macrophage inflammatory protein 3alpha is involved in the constitutive trafficking of epidermal langerhans cells.

Charbonnier AS, Kohrgruber N, Kriehuber E, Stingl G, Rot A, Maurer D - J. Exp. Med. (1999)

Bottom Line: LCs lose the migratory responsiveness to MIP-3alpha during their maturation, and non-LC DCs do not acquire MIP-3alpha sensitivity.The notion that MIP-3alpha may be responsible for selective LC recruitment into the epidermis is further supported by the following observations: (a) MIP-3alpha is expressed by keratinocytes and venular endothelial cells in clinically normal appearing human skin; (b) LCs express CC chemokine receptor (CCR)6, the sole MIP-3alpha receptor both in situ and in vitro; and (c) non-LC DCs that are not found in normal epidermis lack CCR6.One type, the LC, responds to MIP-3alpha and enters skin to screen the epidermis constitutively, whereas the other type, the "inflammatory" DC, migrates in response to a wide array of different chemokines and is involved in the amplification and modulation of the inflammatory tissue response.

View Article: PubMed Central - PubMed

Affiliation: Division of Immunology, Department of Dermatology, University of Vienna Medical School, A-1090 Vienna, Austria.

ABSTRACT
Certain types of dendritic cells (DCs) appear in inflammatory lesions of various etiologies, whereas other DCs, e.g., Langerhans cells (LCs), populate peripheral organs constitutively. Until now, the molecular mechanism behind such differential behavior has not been elucidated. Here, we show that CD1a(+) LC precursors respond selectively and specifically to the CC chemokine macrophage inflammatory protein (MIP)-3alpha. In contrast, CD14(+) precursors of DC and monocytes are not attracted by MIP-3alpha. LCs lose the migratory responsiveness to MIP-3alpha during their maturation, and non-LC DCs do not acquire MIP-3alpha sensitivity. The notion that MIP-3alpha may be responsible for selective LC recruitment into the epidermis is further supported by the following observations: (a) MIP-3alpha is expressed by keratinocytes and venular endothelial cells in clinically normal appearing human skin; (b) LCs express CC chemokine receptor (CCR)6, the sole MIP-3alpha receptor both in situ and in vitro; and (c) non-LC DCs that are not found in normal epidermis lack CCR6. The mature forms of LCs and non-LC DCs display comparable sensitivity for MIP-3beta, a CCR7 ligand, suggesting that DC subtype-specific chemokine responses are restricted to the committed precursor stage. Although LC precursors express primarily CCR6, non-LC DC precursors display a broad chemokine receptor repertoire. These findings reflect a scenario where the differential expression of chemokine receptors by two different subpopulations of DCs determines their functional behavior. One type, the LC, responds to MIP-3alpha and enters skin to screen the epidermis constitutively, whereas the other type, the "inflammatory" DC, migrates in response to a wide array of different chemokines and is involved in the amplification and modulation of the inflammatory tissue response.

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RT-PCR analysis of transcripts encoding chemokine receptors in different DC types generated in vitro and purified ex vivo. cDNAs from the following cell populations were prepared and subjected to PCR: (A) in vitro–generated LCs, derived from flow-sorted CD1a+ LC precursors of 6-d-old CD34+ HPC cultures, analyzed on day 12; (B) epidermal LCs, freshly isolated from skin and purified by FACS®; (C) flow-sorted epidermal LCs cultured for 48 h in the presence of GM-CSF/TNF-α; (D) bulk progeny of GM-CSF/TNF-α–stimulated CD34+ HPCs at day 6; (E) freshly isolated CD11c+ PB-DCs. RT, reverse transcription of mRNA; M, molecular size markers. For primer sequences, see Table .
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Figure 5: RT-PCR analysis of transcripts encoding chemokine receptors in different DC types generated in vitro and purified ex vivo. cDNAs from the following cell populations were prepared and subjected to PCR: (A) in vitro–generated LCs, derived from flow-sorted CD1a+ LC precursors of 6-d-old CD34+ HPC cultures, analyzed on day 12; (B) epidermal LCs, freshly isolated from skin and purified by FACS®; (C) flow-sorted epidermal LCs cultured for 48 h in the presence of GM-CSF/TNF-α; (D) bulk progeny of GM-CSF/TNF-α–stimulated CD34+ HPCs at day 6; (E) freshly isolated CD11c+ PB-DCs. RT, reverse transcription of mRNA; M, molecular size markers. For primer sequences, see Table .

Mentions: To see (a) whether a correlation exists between the chemokine expression pattern and the migratory properties of different types of DCs, and (b) whether our findings are relevant to the in vivo situation, we analyzed the chemokine receptor profile of in vitro–generated LCs and freshly isolated epidermal LCs. As shown in Fig. 5 B, epidermal LCs express mRNAs encoding CCR6, CCR7, and CXCR4, which are the receptors for MIP-3α, MIP-3β/SLC, and SDF-1, respectively. In contrast, these cells are virtually devoid of CCR1, CCR3, and CCR5 transcripts, and express only limited amounts of CCR2 mRNA. Although a similarly restricted set of chemokine receptor mRNAs was expressed by in vitro–generated LCs (Fig. 5 A), other types of immature DCs and DC precursors, i.e., the progeny of cytokine-stimulated CD34+ HPCs at day 6 (Fig. 5 D), blood DCs (Fig. 5 E), and monocyte and/or mdDCs 101331, express mRNA for a wide array of different chemokine receptors, including CCR1, CCR2, CCR3, CCR5, and CXCR4. These two different patterns were mirrored by the FACS® data of chemokine receptor expression on the surface of in vitro–generated LC versus non-LC DC precursors (Fig. 6 A). CCR6 was the only chemokine receptor among those studied that was present on the surface of CD1a+ LC precursors (Fig. 6 A). Curiously, CXCR4 was not detected on the surface of these cells, but was found in their cytoplasm (Fig. 6 A; data not shown). In contrast, CD14+ DC precursors expressed several chemokine receptors, including CCR1 and CCR5, thus suggesting that the migratory responses to MIP-1α seen in Fig. 2 are indeed confined to this subset.


Macrophage inflammatory protein 3alpha is involved in the constitutive trafficking of epidermal langerhans cells.

Charbonnier AS, Kohrgruber N, Kriehuber E, Stingl G, Rot A, Maurer D - J. Exp. Med. (1999)

RT-PCR analysis of transcripts encoding chemokine receptors in different DC types generated in vitro and purified ex vivo. cDNAs from the following cell populations were prepared and subjected to PCR: (A) in vitro–generated LCs, derived from flow-sorted CD1a+ LC precursors of 6-d-old CD34+ HPC cultures, analyzed on day 12; (B) epidermal LCs, freshly isolated from skin and purified by FACS®; (C) flow-sorted epidermal LCs cultured for 48 h in the presence of GM-CSF/TNF-α; (D) bulk progeny of GM-CSF/TNF-α–stimulated CD34+ HPCs at day 6; (E) freshly isolated CD11c+ PB-DCs. RT, reverse transcription of mRNA; M, molecular size markers. For primer sequences, see Table .
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Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2195721&req=5

Figure 5: RT-PCR analysis of transcripts encoding chemokine receptors in different DC types generated in vitro and purified ex vivo. cDNAs from the following cell populations were prepared and subjected to PCR: (A) in vitro–generated LCs, derived from flow-sorted CD1a+ LC precursors of 6-d-old CD34+ HPC cultures, analyzed on day 12; (B) epidermal LCs, freshly isolated from skin and purified by FACS®; (C) flow-sorted epidermal LCs cultured for 48 h in the presence of GM-CSF/TNF-α; (D) bulk progeny of GM-CSF/TNF-α–stimulated CD34+ HPCs at day 6; (E) freshly isolated CD11c+ PB-DCs. RT, reverse transcription of mRNA; M, molecular size markers. For primer sequences, see Table .
Mentions: To see (a) whether a correlation exists between the chemokine expression pattern and the migratory properties of different types of DCs, and (b) whether our findings are relevant to the in vivo situation, we analyzed the chemokine receptor profile of in vitro–generated LCs and freshly isolated epidermal LCs. As shown in Fig. 5 B, epidermal LCs express mRNAs encoding CCR6, CCR7, and CXCR4, which are the receptors for MIP-3α, MIP-3β/SLC, and SDF-1, respectively. In contrast, these cells are virtually devoid of CCR1, CCR3, and CCR5 transcripts, and express only limited amounts of CCR2 mRNA. Although a similarly restricted set of chemokine receptor mRNAs was expressed by in vitro–generated LCs (Fig. 5 A), other types of immature DCs and DC precursors, i.e., the progeny of cytokine-stimulated CD34+ HPCs at day 6 (Fig. 5 D), blood DCs (Fig. 5 E), and monocyte and/or mdDCs 101331, express mRNA for a wide array of different chemokine receptors, including CCR1, CCR2, CCR3, CCR5, and CXCR4. These two different patterns were mirrored by the FACS® data of chemokine receptor expression on the surface of in vitro–generated LC versus non-LC DC precursors (Fig. 6 A). CCR6 was the only chemokine receptor among those studied that was present on the surface of CD1a+ LC precursors (Fig. 6 A). Curiously, CXCR4 was not detected on the surface of these cells, but was found in their cytoplasm (Fig. 6 A; data not shown). In contrast, CD14+ DC precursors expressed several chemokine receptors, including CCR1 and CCR5, thus suggesting that the migratory responses to MIP-1α seen in Fig. 2 are indeed confined to this subset.

Bottom Line: LCs lose the migratory responsiveness to MIP-3alpha during their maturation, and non-LC DCs do not acquire MIP-3alpha sensitivity.The notion that MIP-3alpha may be responsible for selective LC recruitment into the epidermis is further supported by the following observations: (a) MIP-3alpha is expressed by keratinocytes and venular endothelial cells in clinically normal appearing human skin; (b) LCs express CC chemokine receptor (CCR)6, the sole MIP-3alpha receptor both in situ and in vitro; and (c) non-LC DCs that are not found in normal epidermis lack CCR6.One type, the LC, responds to MIP-3alpha and enters skin to screen the epidermis constitutively, whereas the other type, the "inflammatory" DC, migrates in response to a wide array of different chemokines and is involved in the amplification and modulation of the inflammatory tissue response.

View Article: PubMed Central - PubMed

Affiliation: Division of Immunology, Department of Dermatology, University of Vienna Medical School, A-1090 Vienna, Austria.

ABSTRACT
Certain types of dendritic cells (DCs) appear in inflammatory lesions of various etiologies, whereas other DCs, e.g., Langerhans cells (LCs), populate peripheral organs constitutively. Until now, the molecular mechanism behind such differential behavior has not been elucidated. Here, we show that CD1a(+) LC precursors respond selectively and specifically to the CC chemokine macrophage inflammatory protein (MIP)-3alpha. In contrast, CD14(+) precursors of DC and monocytes are not attracted by MIP-3alpha. LCs lose the migratory responsiveness to MIP-3alpha during their maturation, and non-LC DCs do not acquire MIP-3alpha sensitivity. The notion that MIP-3alpha may be responsible for selective LC recruitment into the epidermis is further supported by the following observations: (a) MIP-3alpha is expressed by keratinocytes and venular endothelial cells in clinically normal appearing human skin; (b) LCs express CC chemokine receptor (CCR)6, the sole MIP-3alpha receptor both in situ and in vitro; and (c) non-LC DCs that are not found in normal epidermis lack CCR6. The mature forms of LCs and non-LC DCs display comparable sensitivity for MIP-3beta, a CCR7 ligand, suggesting that DC subtype-specific chemokine responses are restricted to the committed precursor stage. Although LC precursors express primarily CCR6, non-LC DC precursors display a broad chemokine receptor repertoire. These findings reflect a scenario where the differential expression of chemokine receptors by two different subpopulations of DCs determines their functional behavior. One type, the LC, responds to MIP-3alpha and enters skin to screen the epidermis constitutively, whereas the other type, the "inflammatory" DC, migrates in response to a wide array of different chemokines and is involved in the amplification and modulation of the inflammatory tissue response.

Show MeSH
Related in: MedlinePlus